The 100 most-cited articles in The FASEB Journal, 2019

Severe acute respiratory syndrome coronavirus (SARS-CoV) is capable of inducing a storm of proinflammatory cytokines. In this study, we show that the SARS-CoV open reading frame 3a (ORF3a) accessory protein activates the NLRP3 inflammasome by promoting TNF receptor-associated factor 3 (TRAF3)-mediated ubiquitination of apoptosis-associated speck-like protein containing a caspase recruitment domain (ASC). SARS-CoV and its ORF3a protein were found to be potent activators of pro-IL-1β gene transcription and protein maturation, the 2 signals required for activation of the NLRP3 inflammasome. ORF3a induced pro-IL-1β transcription through activation of NF-κB, which was mediated by TRAF3-dependent ubiquitination and processing of p105. ORF3a-induced elevation of IL-1β secretion was independent of its ion channel activity or absent in melanoma 2 but required NLRP3, ASC, and TRAF3. ORF3a interacted with TRAF3 and ASC, colocalized with them in discrete punctate structures in the cytoplasm, and facilitated ASC speck formation. TRAF3-dependent K63-linked ubiquitination of ASC was more…

Diabetes mellitus (DM) affects bone metabolism and leads to osteoporosis; however, its pathogenetic mechanisms remain unknown. We found that high glucose (HG) conditions induced the production of reactive oxygen species (ROS) and the expression of proteins related to MAPKs [phosphorylated (p)‐ERK, p‐JNK, and p‐p38], NF‐ κ B(NF‐ κ B, p‐IαB, and IKK), and NACHT‐LRR‐PYD domains‐containing protein 3 (NALP3) (NLRP3) [apoptosis‐associated speck‐like protein containing a caspase activation and recruitment domain (ASC), caspase‐1, IL‐18, IL‐1β, and NLRP3] in osteoclasts (OCs) in vitro . Further analysis showed that in HG‐induced OCs, ROS is an upstream signal for MAPKs, NF‐ κ B, and the NLRP3 inflammasome. Moreover, MAPKs mediated the activation of NF‐ κ B and NLRP3, whereas NF‐ κ B up‐regulated the NLRP3 inflammasome response. Interestingly, HG inducement enhanced the bone resorption of OCs but inhibited their efferocytosis, whereas insulin and lipoxin A4 (4) treatment reversed this phenomenon. In streptozotocin‐induced diabetic rats in vivo , the numbers and the bone‐resorption capacity…

Hydrogen sulfide can signal through 3 distinct mechanisms: 1) reduction and/or direct binding of metalloprotein heme centers, 2) serving as a potent antioxidant through reactive oxygen species/reactive nitrogen species scavenging, or 3) post‐translational modification of proteins by addition of a thiol (‐SH) group onto reactive cysteine residues: a process known as persulfidation. Below toxic levels, hydrogen sulfide promotes mitochondrial biogenesis and function, thereby conferring protection against cellular stress. For these reasons, increases in hydrogen sulfide and hydrogen sulfide‐producing enzymes have been implicated in several human disease states. This review will first summarize our current understanding of hydrogen sulfide production and metabolism, as well as its signaling mechanisms; second, this work will detail the known mechanisms of hydrogen sulfide in the mitochondria and the implications of its mitochondrial‐specific impacts in several pathologic conditions.—Murphy, B., Bhattacharya, R., Mukherjee, P. Hydrogen sulfide signaling in mitochondria and disease. FASEB…

ABSTRACT Acute kidney injury is a common complication of rhabdomyolysis. A better understanding of this syndrome may be useful to identify novel therapeutic targets because there is no specific treatment so far. Ferroptosis is an iron‐dependent form of regulated nonapoptotic cell death that is involved in renal injury. In this study, we investigated whether ferroptosis is associated with rhabdomyolysis‐mediated renal damage, and we studied the therapeutic effect of curcumin, a powerful antioxidant with renoprotective properties. Induction of rhabdomyolysis in mice increased serum creatinine levels, endothelial damage, inflammatory chemokines, and cytokine expression, alteration of redox balance (increased lipid peroxidation and decreased antioxidant defenses), and tubular cell death. Treatment with curcumin initiated before or after rhabdomyolysis induction ameliorated all these pathologic and molecular alterations. Although apoptosis or receptor‐interacting protein kinase (RIPK)3‐mediated necroptosis were activated in rhabdomyolysis, our results suggest a key role of ferroptosis.…

Among the main bacteria implicated in the pathology of periodontal disease, Aggregatibacter actinomycetemcomitans (Aa) is well known for causing loss of periodontal attachment and systemic disease. Recent studies have suggested that secreted extracellular RNAs (exRNAs) from several bacteria may be important in periodontitis, although their role is unclear. Emerging evidence indicates that exRNAs circulate in nanosized bilayered and membranous extracellular vesicles (EVs) known as outer membrane vesicles (OMVs) in gram‐negative bacteria. In this study, we analyzed the small RNA expression profiles in activated human macrophage‐like cells (U937) infected with OMVs from Aa and investigated whether these cells can harbor exRNAs of bacterial origin that have been loaded into the host RNA‐induced silencing complex, thus regulating host target transcripts. Our results provide evidence for the cytoplasmic delivery and activity of microbial EV‐derived small exRNAs in host gene regulation. The production of TNF‐α was promoted by exRNAs via the TLR‐8 and NF‐κB signaling pathways. Numerous…

ABSTRACT Apolipoprotein E ( APOE ) genotype is the strongest prevalent genetic risk factor for Alzheimer's disease (AD). Numerous studies have provided insights into the pathologic mechanisms. However, a comprehensive understanding of the impact of APOE genotype on microflora speciation and metabolism is completely lacking. In this study, we investigated the association between APOE genotype and the gut microbiome composition in human and APOE–targeted replacement (TR) transgenic mice. Fecal microbiota amplicon sequencing from matched individuals with different APOE genotypes revealed no significant differences in overall microbiota diversity in group‐aggregated human APOE genotypes. However, several bacterial taxa showed significantly different relative abundance between APOE genotypes. Notably, we detected an association of Prevotellaceae and Ruminococcaceae and several butyrate‐producing genera abundances with APOE genotypes. These findings were confirmed by comparing the gut microbiota of APOE ‐TR mice. Furthermore, metabolomic analysis of murine fecal water detected significant…

ABSTRACT During hypoxia, a cellular adaptive response activates hypoxia‐inducible factors (HIFs; HIF‐1 and HIF‐2) that respond to low tissue‐oxygen levels and induce the expression of a number of genes that promote angiogenesis, energy metabolism, and cell survival. HIF‐1 and HIF‐2 regulate endothelial cell (EC) adaptation by activating genesignaling cascades that promote endothelial migration, growth, and differentiation. An HIF‐1 to HIF‐2 transition or switch governs this process from acute to prolonged hypoxia. In the present study, we evaluated the mechanisms governing the HIF switch in 10 different primary human ECs from different vascular beds during the early stages of hypoxia. The studies demonstrate that the switch from HIF‐1 to HIF‐2 constitutes a universal mechanism of cellular adaptation to hypoxic stress and that HIF1A and HIF2A mRNA stability differences contribute to HIF switch. Furthermore, using 4 genome‐wide mRNA expression arrays of HUVECs during normoxia and after 2, 8, and 16 h of hypoxia, we show using bioinformatics analyses that, although a number of genes…

ABSTRACT Blockade of immune‐checkpoint programmed cell death protein 1 (PD‐1) or programmed cell death ligand 1 can enhance effector T‐cell responses. However, the lack of response in many patients to checkpoint‐inhibitor therapies emphasizes the need for combination immunotherapies to pursue maximal antitumor efficacy. We have previously demonstrated that antagonism of C‐X‐C chemokine receptor type 4 (CXCR4) by plerixafor (AMD3100) can decrease regulatory T (T reg )‐cell intratumoral infiltration. Therefore, a combination of these 2 therapies might increase antitumor effects. Here, we evaluated the antitumor efficacy of AMD3100 and anti‐PD‐1 (αPD‐1) antibody alone or in combination in an immunocompetent syngeneic mouse model of ovarian cancer. We found that AMD3100, a highly specific CXCR4 antagonist, directly down‐regulated the expression of both C‐X‐C motif chemokine 12 (CXCL12) and CXCR4 in vitro and in vivo in tumor cells. AMD3100 and αPD‐1 significantly inhibited tumor growth and prolonged the survival of tumor‐bearing mice when given as monotherapy. Combination of these 2…

ABSTRACT Endometriosis is a common incurable inflammatory disorder that is associated with debilitating pelvic pain in women. Macrophages are central to the pathophysiology of endometriosis: they dictate the growth and vascularization of endometriosis lesions and more recently have been shown to promote lesion innervation. The aim of this study was to determine the mechanistic role of macrophages in producing pain associated with endometriosis. Herein, we show that macrophage depletion in a mouse model of endometriosis can reverse abnormal changes in pain behavior. We identified that disease‐modified macrophages exhibit increased expression of IGF‐1 in an in vitro model of endometriosis‐associated macrophages and confirmed expression by lesion‐resident macrophages in mice and women. Concentrations of IGF‐1 were elevated in peritoneal fluid from women with endometriosis and positively correlate with their pain scores. Mechanistically, we demonstrate that macrophage‐derived IGF‐1 promotes sprouting neurogenesis and nerve sensitization in vitro . Finally, we show that the Igf‐1…

Doxorubicin (Dox) is a widely used antineoplastic agent that can cause heart failure. Dox cardiotoxicity is closely associated with mitochondrial damage. Mitochondrial fission and mitophagy are quality control mechanisms that normally help maintain a pool of healthy mitochondria. However, unchecked mitochondrial fission and mitophagy may compromise the viability of cardiomyocytes, predisposing them to cell death. Here, we tested this possibility by using Dox-treated H9c2 cardiac myoblast cells expressing either the mitochondria-targeted fluorescent protein MitoDsRed or the novel dual-fluorescent mitophagy reporter mt-Rosella. Dox induced mitochondrial fragmentation as shown by reduced form factor, aspect ratio, and mean mitochondrial size. This effect was abolished by short interference RNA-mediated knockdown of dynamin-related protein 1 (DRP1), a major regulator of fission. Importantly, DRP1 knockdown decreased cell death as indicated by the reduced number of propidium iodide-positive cells and the cleavage of caspase-3 and poly (ADP-ribose) polymerase. Moreover, DRP1-deficient…

Parkinson's disease (PD) is a neurodegenerative disorder characterized by motor and nonmotor symptoms due to the selective loss of midbrain dopaminergic neurons. The evidence for a chronic inflammatory reaction mediated by microglial cells in the brain is particularly strong in PD. In our previous study, we have shown that brain-specific microRNA-124 (miR-124) is significantly down-regulated in the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced mouse model of PD and that it can also inhibit neuroinflammation during the development of PD. However, further investigation is required to understand whether the abnormal expression of miR-124 regulates microglial activation. In this study, we found that the expression of sequestosome 1 (p62) and phospho-p38 mitogen-activated protein kinases (p-p38) showed a significant increase in LPS-treated immortalized murine microglial cell line BV2 cells in an MPTP-induced mouse model of PD. Knockdown of p62 could suppress the secretion of proinflammatory cytokines and p-p38 of microglia. Besides, inhibition of p38 suppressed the…

ABSTRACT The gastric pathogen Helicobacter pylori activates the NF‐κB pathway in human epithelial cells via the recently discovered α‐kinase 1 TRAF‐interacting protein with forkhead‐associated domain (TIFA) axis. We and others showed that this pathway can be triggered by heptose 1,7‐bisphosphate (HBP), an LPS intermediate produced in gram‐negative bacteria that represents a new pathogen‐associated molecular pattern (PAMP). Here, we report that our attempts to identify HBP in lysates of H. pylori revealed surprisingly low amounts, failing to explain NF‐κB activation. Instead, we identified ADP ‐glycero‐ β‐D‐ manno‐ heptose (ADP heptose), a derivative of HBP, as the predominant PAMP in lysates of H. pylori and other gram‐negative bacteria. ADP heptose exhibits significantly higher activity than HBP, and cells specifically sensed the presence of the β‐form, even when the compound was added extracellularly. The data lead us to conclude that ADP heptose not only constitutes the key PAMP responsible for H. pylori –induced NF‐κB activation in epithelial cells, but it acts as a general…

Psoriasis is a chronic inflammatory skin disease that severely affects patients physiologically and psychologically. The pathogenesis involving communication between psoriatic keratinocytes and infiltrated immune cells such as neutrophils remains unclear. Exosomes are emerging mediators of intercellular communication. Herein we aim to investigate the release and function of psoriatic keratinocyte exosomes, which have not been illustrated to any extent. We first isolated exosomes from both healthy and psoriasis‐like keratinocytes treated with psoriatic cytokine cocktail. These exosomes were observed to be endocytosed by neutrophils. Unlike non‐cytokine‐treated keratinocyte exosomes, cytokine‐treated keratinocyte exosomes significantly induced NETosis (the process by which neutrophils produce and release neutrophil extracellular traps) and the expressions of IL‐6, IL‐8, and TNF‐α in neutrophils. Proteomic analysis showed that cytokine‐treated keratinocyte exosomes exhibited a specific protein profile with proteins enriched in immune‐related pathways. We then confirmed that NF‐κB and…

ABSTRACT Bone marrow stem cells (BMSCs) are multipotent stem cells that can regenerate mesenchymal tissues, such as adipose tissue, bone, and muscle. Recent studies have shown that N 6 ‐methyladenosine (m 6 A) methylation, one of the most prevalent epigenetic modifications, is involved in the development process. However, whether it plays roles in BMSC differentiation is still elusive. Here, we found that the deletion of m 6 A “writer” protein methyltransferase‐like (METTL)3 in porcine BMSCs (pBMSCs) could promote adipogenesis and janus kinase (JAK)1 protein expression via an m 6 A‐dependent way. Knockdown of METTL3 decreased mRNA m 6 A levels of JAK1, leading to enhanced YTH m 6 A RNA binding protein 2 (YTHDF2)‐dependent JAK1 mRNA stability. We further demonstrated that JAK1 activated signal transducer and activator of transcription (STAT) 5 through regulation of its phosphorylation to bind to the promoter of CCAAT/enhancer binding protein (C/EBP) β, which could ultimately lead to a modulated adipogenic process. Collectively, our results reveal an orchestrated network linking the m…

ABSTRACT Nonsteroidal anti‐inflammatory drugs interfere with the metabolism of arachidonic acid to proinflammatory prostaglandins and leukotrienes by targeting cyclooxygenases (COXs), 5‐lipoxygenase (LOX), or the 5‐LOX–activating protein (FLAP). These and related enzymes act in conjunction with marked crosstalk within a complex lipid mediator (LM) network where also specialized proresolving LMs (SPMs) are formed. Here, we present how prominent LM pathways can be differentially modulated in human proinflammatory M1 and proresolving M2 macrophage phenotypes that, upon exposure to Escherichia coli , produce either abundant prostaglandins and leukotrienes (M1) or SPMs (M2). Targeted liquid chromatography–tandem mass spectrometry–based metabololipidomics was applied to analyze and quantify the specific LM profiles. Besides expected on‐target actions, we found that: 1 ) COX or 15‐LOX‐1 inhibitors elevate inflammatory leukotriene levels, 2 ) FLAP and 5‐LOX inhibitors reduce leukotrienes in M1 but less so in M2 macrophages, 3 ) zileuton blocks resolution‐initiating SPM biosynthesis, whereas…

The gastrointestinal microbiota is emerging as a unique and inexhaustible source for metabolites with potential to modulate G‐protein coupled receptors (GPCRs). The ghrelin receptor [growth hormone secretagogue receptor (GHSR)‐1a] is a GPCR expressed throughout both the gut and the brain and plays a crucial role in maintaining energy balance, metabolism, and the central modulation of food intake, motivation, reward, and mood. To date, few studies have investigated the potential of the gastrointestinal microbiota and its metabolites to modulate GPCR signaling. Here we investigate the ability of short‐chain fatty acids (SCFAs), lactate, and different bacterial strains, including Bifidobacterium and Lactobacillus genera, to modulate GHSR‐1a signaling. We identify, for what is to our knowledge the first time, a potent effect of microbiota‐derived metabolites on GHSR‐1a signaling with potential significant consequences for host metabolism and physiology. We show that SCFAs, lactate, and bacterial supernatants are able to attenuate ghrelin‐mediated signaling through the GHSR‐1a. We…

ABSTRACT Omega‐3 (n‐3) fatty acid supplementation enhances muscle protein synthesis and muscle size. Whether n‐3 fatty acid supplementation attenuates human muscle disuse atrophy is unknown. We determined the influence of n‐3 fatty acid supplementation on muscle size, mass, and integrated rates of myofibrillar protein synthesis (MyoPS) following 2 wk of muscle disuse and recovery in women. Twenty women (BMI = 23.0 ± 2.3 kg/m 2 , age = 22 ± 3 yr) underwent 2 wk of unilateral limb immobilization followed by 2 wk of return to normal activity. Starting 4 wk prior to immobilization, participants consumed either 5 g/d of n‐3 fatty acid or an isoenergetic quantity of sunflower oil (control). Muscle size and mass were measured pre‐ and postimmobilization, and after recovery. Serial muscle biopsies were obtained to measure integrated (daily) MyoPS. Following immobilization, the decline in muscle volume was greater in the control group compared to the n‐3 fatty acid group (14 vs . 8%, P < 0.05) and was not different from preimmobilization at recovery in the n‐3 fatty acid group; however, it…

Blood‐retinal barrier (BRB) breakdown is a typical event in the early stage of diabetic retinopathy (DR). This study aims to elucidate the protection of erianin, a natural compound isolated from Dendrobium chrysotoxum Lindl, against DR development. Erianin alleviated BRB breakdown and rescued the reduced claudin1 and occludin expression in retinas from streptozotocin‐induced diabetic mice. Erianin reduced microglial activation, ERK1/2 phosphorylation, NF‐κB transcriptional activation, and the elevated TNF‐α expression both in vitro and in vivo. ERK1/2 inhibitor U0126 abrogated NF‐κB activation in D‐glucose‐treated BV2 cells. Erianin reduced cellular glucose uptake, and molecular docking analysis indicated the potential interaction of erianin with glucose transporter (GLUT)1. GLUT1 inhibitor (STF31) reduced the activation of the ERK1/2‐NF‐κB signaling pathway. Coculture with D‐glucose‐stimulated microglial BV2 cells and with TNF‐α stimulation both induced inner BRB and outer BRB damage in human retinal endothelial cells and APRE19 cells, but erianin improved all these damages. In…

ABSTRACT The C57BL/10ScSn‐ Dmd mdx /J (BL10 ‐mdx ) mouse has been the most commonly used model for Duchenne muscular dystrophy (DMD) for decades. Their muscle dysfunction and pathology is, however, less severe than in patients with DMD, which complicates preclinical studies. Recent discoveries indicate that disease severity is exacerbated when muscular dystrophy mouse models are generated on a DBA2/J genetic background. Knowledge on the natural history of animal models is pivotal for high‐quality preclinical testing. However, for BL10 ‐mdx mice on a DBA2/J background (D2 ‐mdx ), limited data are available. We addressed this gap in the natural history knowledge. First, we compared histopathological aspects in skeletal muscles of young D2 ‐mdx , BL10 ‐mdx , and wild‐type mice. Pathology was more pronounced in D2 ‐mdx mice and differed in severity between muscles within individuals. Secondly, we subjected D2‐ mdx mice to a functional test regime for 34 weeks and identified that female D2‐ mdx mice outperform severely impaired males, making females less useful for functional preclinical…

Loss-of-function genetic variants of triggering receptor expressed on myeloid cells 2 (TREM2) are linked with an enhanced risk of developing dementias. Microglia, the resident immune cell of the brain, express TREM2, and microglial responses are implicated in dementia pathways. In a normal surveillance state, microglia use oxidative phosphorylation for their energy supply, but rely on the ability to undergo a metabolic switch to glycolysis to allow them to perform rapid plastic responses. We investigated the role of TREM2 on the microglial metabolic function in human patient iPSC-derived microglia expressing loss of function variants in TREM2. We show that these TREM2 variant iPSC-microglia, including the Alzheimer's disease R47H risk variant, exhibit significant metabolic deficits including a reduced mitochondrial respiratory capacity and an inability to perform a glycolytic immunometabolic switch. We determined that dysregulated PPARγ/p38MAPK signaling underlies the observed phenotypic deficits in TREM2 variants and that activation of these pathways can ameliorate the metabolic…

Abstract Changes in mitochondrial size and shape have been implicated in several physiological processes, but their role in mitochondrial Ca 2+ uptake regulation and overall cellular Ca 2+ homeostasis is largely unknown. Here we show that modulating mitochondrial dynamics towards increased fusion through expression of a dominant negative form of the fission protein DRP1 (DRP1‐DN) markedly increased both mitochondrial Ca 2+ retention capacity and Ca 2+ uptake rates in permeabilized C2C12 cells. Similar results were seen using the pharmacological fusion‐promoting M1 molecule. Conversely, promoting a fission phenotype through the knockdown of the fusion protein mitofusin 2 (MFN2) strongly reduced mitochondrial Ca 2+ uptake speed and capacity in these cells. These changes were not dependent on modifications in inner membrane potentials or the mitochondrial permeability transition. Implications of mitochondrial morphology modulation on cellular calcium homeostasis were measured in intact cells; mitochondrial fission promoted lower basal cellular calcium levels and lower endoplasmic…

Adipose tissue–secreted extracellular vesicles (EVs) containing microRNAs (miRNAs) convey intercellular message signaling. The biogenesis of EV‐miRNAs from perivascular adipose tissue (PVAT) and their roles in intercellular communication in response to obesity‐associated inflammation have not yet been fully explored. By feeding mice a high‐fat diet for 16 wk, we established obesity‐associated, chronic low‐grade inflammation in PVAT, characterized as hypertrophy of perivascular adipocytes, decreased adipogenesis, and proinflammatory macrophage infiltration. We show that PVAT‐derived EVs and their encapsulated miRNAs can be taken up into vascular smooth muscle cells (VSMCs) in vivo and in vitro . miR‐221‐3p is one of the highly enriched miRNAs in obese PVAT and PVAT‐derived EVs. Transfer and direct overexpression of miR‐221‐3p dramatically enhances VSMC proliferation and migration. Peroxisome proliferator–activated receptor γ coactivator 1α is identified as a miR‐221‐3p target in VSMC phenotypic modulation. Obese mice secrete abundant miRNA‐containing EVs, evoking inflammatory…

ABSTRACT The mechanism of exosomes derived from activated hepatic stellate cells (HSCs) involved in liver fibrosis is poorly understood. We previously reported that hypoxia‐inducible factor 1 (Hif‐1) regulated HSC activation, and, therefore, we investigated in current work whether Hif‐1 regulates exosome secretion and the metabolic switch of HSCs, thus affecting the metabolism of liver nonparenchymal cells. In this study, the characteristics of exosomes from HSCs were assessed via electron microscopy, Western blot analysis, and acetylcholinesterase activity. Confocal microscopy was used to measure the uptake of exosomes by quiescent HSCs, Kupffer cells (KCs), and liver sinusoidal endothelial cells (LSECs). Hif‐1α was inhibited via 2‐ME or specific small interfering RNAs to investigate its role in exosomes derived from HSCs. It was determined that glucose transporter 1 and pyruvate kinase M2 were increasingly expressed in fibrotic liver samples, cell lysates, and exosomes derived from activated HSCs. Exosomes released from HSCs were associated with activation and glucose uptake of…

The gut microbiota plays a critical role in various physiologic processes; however, maternal microbial and metabolic changes during pregnancy and lactation remain elusive. Using pigs as an animal model, we conducted comparative analyses of gut microbiota and short-chain fatty acid (SCFA) profiles across different stages of gestation, lactation, and the empty (nonpregnancy) phase in 2 distinct breeds of sow, Rongchang (RS) and Landrace (LS). Coriobacteriaceae were found to gradually increase over gestational time irrespective of breed, which was further validated in an independent cohort of sows, indicating that Coriobacteriaceae are likely associated with the progression of pregnancy. Escherichia increased as well. Relative to empty and gestation, lactation was associated with an increase in SCFA producers and a concomitant augmentation in SCFA production in both breeds. A comparison between the 2 breeds revealed that Ruminococcaceae were more abundant in RSs than in LSs, consistent with the strong ability of Rongchang pigs to digest highly fibrous feedstuffs. Taken together, we…

Beyond their contribution as fundamental building blocks of life, branched-chain amino acids (BCAAs) play a critical role in physiologic and pathologic processes. Importantly, BCAAs are associated with insulin resistance, obesity, cardiovascular disease, and genetic disorders. However, several metabolome-wide studies in recent years could not attribute alterations in systemic BCAAs as the sole driver of endocrine perturbations, suggesting that a snapshot of global BCAA changes does not always reveal the underlying modifications. Because enzymes catabolizing BCAAs have a unique distribution, it is plausible that the tissue-specific roles of BCAA-catabolic enzymes could precipitate changes in systemic BCAA levels, flux, and action. We review the genetic and pharmacological approaches dissecting the role of BCAA-catabolic enzyme dysfunctions. We summarized emerging evidence on BCAA metabolic intermediates, tissue specificity of BCAA-catabolizing enzymes, and crosstalk between different metabolites in driving metabolic maladaptation in health and pathology. This review substantiates the…

ABSTRACT Although the role of the Hippo signaling pathway in development and tumorigenesis has been extensively studied in multiple organs, its role in ovarian follicle development remains largely unknown. Here, we report that Yes‐Associated Protein 1 (YAP1), the major effector of Hippo signaling, is spatiotemporally expressed in ovarian granulosa cells and plays a critical role in the regulation of follicle development. We found that the active form of YAP1 (nuclear YAP1) was predominantly expressed in proliferative granulosa cells, whereas the inactive form of YAP1 (cytoplasmic YAP1) was mainly detected in luteal cells (terminally differentiated granulosa cells). Pharmacological inhibition of YAP1 activity disrupted mouse ovarian follicle development in vitro and in vivo. Foxl2 promoter–driven knockout of Yap1 in ovarian granulosa cells resulted in increased apoptosis of granulosa cells, decreased number of corpora lutea, reduced ovarian size, and subfertility in transgenic mice. However, Cyp19a1 promoter–driven knockout of Yap1 in differentiated granulosa cells of preovulatory…

ABSTRACT Bisphosphonate‐related osteonecrosis of the jaw (BRONJ) is a detrimental side effect of the long‐term administration of bisphosphonates. Although macrophages were reported to be an important mediator of BRONJ, the detailed potential mechanism of BRONJ remains unclear. Here, we reported an elevated TLR‐4 expression in macrophages under action of zoledronic acid (ZA), resulting in enhanced M1 macrophage polarization and decreased M2 macrophage polarization both in vitro and in vivo . After inhibiting the TLR‐4 signaling pathway, the activation of the TLR‐4/NF‐κB signaling pathway and the induction of NF‐κB nuclear translocation and production of proinflammatory cytokines by ZA were suppressed in macrophages, thereby inhibiting M1 macrophage polarization. By utilizing the TLR‐4 −/− mice, development of BRONJ was markedly ameliorated, and M1 macrophages were significantly attenuated in the extraction socket tissues in the TLR‐4 −/− mice. Importantly, the systemic administration of the TLR‐4 inhibitor TAK‐242 improved the wound healing of the extraction socket and decreased the…

Increased pro-inflammatory cytokine levels and proliferation of activated microglia have been found in Parkinson's disease (PD) patients and animal models of PD, suggesting that targeting of the microglial inflammatory response may result in neuroprotection in PD. Microglial proliferation is regulated by many factors, but colony stimulating factor-1 receptor (CSF1R) has emerged as a primary factor. Using data mining techniques on existing microarray data, we found that mRNA expression of the CSF1R ligand, CSF-1, is increased in the brain of PD patients compared to controls. In two different neurotoxic mouse models of PD, acute MPTP and sub-chronic LPS treatment, mRNA and protein levels of CSF1R and CSF-1 were significantly increased. Treatment with the CSF1R inhibitor GW2580 significantly attenuated MPTP-induced CSF1R activation and Iba1-positive cell proliferation, without a reduction of the basal Iba1-positive population in the substantia nigra. GW2580 treatment also significantly decreased mRNA levels of pro-inflammatory factors, without alteration of anti-inflammatory mediators,…

Mitochondrial fission is important in physiological processes, including coordination of mitochondrial and nuclear division during mitosis, and pathologic processes, such as the production of reactive oxygen species (ROS) during cardiac ischemia-reperfusion injury (IR). Mitochondrial fission is mainly mediated by dynamin-related protein 1 (Drp1), a large GTPase. The GTPase activity of Drp1 is essential for its fissogenic activity. Therefore, we aimed to identify Drp1 inhibitors and evaluate their anti-neoplastic and cardioprotective properties in five cancer cell lines (A549, SK-MES-1, SK-LU-1, SW 900, and MCF7) and an experimental cardiac IR injury model. Virtual screening of a chemical library revealed 17 compounds with high predicted affinity to the GTPase domain of Drp1. In silico screening identified an ellipticine compound, Drpitor1, as a putative, potent Drp1 inhibitor. We also synthesized a congener of Drpitor1 to remove the methoxymethyl group and reduce hydrolytic lability (Drpitor1a). Drpitor1 and Drpitor1a inhibited the GTPase activity of Drp1 without inhibiting the…

ABSTRACT Short‐chain fatty acids (SCFAs) are gut microbiota‐derived products that participate in maintaining the gut barrier integrity and host's immune response. We hypothesize that reduced SCFA levels are associated with systemic inflammation, endotoxemia, and more severe hemodynamic alterations in cirrhosis. Patients with cirrhosis referred for a hepatic venous pressure gradient (HVPG) measurement ( n = 62) or a transjugular intrahepatic portosystemic shunt placement ( n = 12) were included. SCFAs were measured in portal (when available), hepatic, and peripheral blood samples by GC‐MS. Serum endotoxins, proinflammatory cytokines, and NO levels were quantified. SCFA levels were significantly higher in portal vs . hepatic and peripheral blood. There were inverse relationships between SCFAs and the severity of disease. SCFAs (mainly butyric acid) inversely correlated with the model for end‐stage liver disease score and were further reduced in patients with history of ascites, hepatic encephalopathy, and spontaneous bacterial peritonitis. There was an inverse relationship between…

ABSTRACT Sorafenib is a multikinase inhibitor that is effective in treating advanced liver cancer. Although its mechanism of action through several established cancer‐related protein kinase targets is well‐characterized, sorafenib induces variable responses among human tumors, and the cause for this variation is yet unknown. To investigate the underlying mechanisms, we applied mass spectrometry‐based proteomic analysis to Huh7.5 human liver cancer cells and found that sorafenib significantly affected the expression of the key lipogenic enzymes, especially stearoyl coenzyme A desaturase 1 (SCD1), in these cells. Given that SCD1 catalyzes the most crucial and rate‐limiting step in the synthesis of monounsaturated fatty acids (FAs), we performed a lipidomic analysis, which showed a dramatically altered lipid profile in sorafenib‐treated cells. Detection and analysis of free FAs showed that the levels of monounsaturated FAs, including oleate, were significantly decreased in those cells treated by sorafenib. Addition of oleate protected liver cancer cells from sorafenib‐induced death and…

ABSTRACT Amyloid β‐protein (Aβ) molecules tend to aggregate and subsequently form low MW (LMW) oligomers, high MW (HMW) aggregates such as protofibrils, and ultimately fibrils. These Aβ species can generally form amyloid plaques implicated in the neurodegeneration of Alzheimer disease (AD), but therapies designed to reduce plaque load have not demonstrated clinical efficacy. Recent evidence implicates amyloid oligomers in AD neuropathology, but the precise mechanisms are uncertain. We examined the mechanisms of neuronal dysfunction from HMW‐Aβ 1‐42 exposure by measuring membrane integrity, reactive oxygen species (ROS) generation, membrane lipid peroxidation, membrane fluidity, intracellular calcium regulation, passive membrane electrophysiological properties, and long‐term potentiation (LTP). HMW‐Aβ 1‐42 disturbed membrane integrity by inducing ROS generation and lipid peroxidation, resulting in decreased membrane fluidity, intracellular calcium dysregulation, depolarization, and impaired LTP. The damaging effects of HMW‐Aβ 1‐42 were significantly greater than those of LMW‐Aβ 1‐42…

ABSTRACT Recent reports attribute numerous regulatory functions to the nuclear paraspeckle‐forming long non‐coding RNA, nuclear enriched assembly transcript 1 (NEAT1), but the implications of its involvement in Parkinson's disease (PD) remain controversial. To address this issue, we assessed NEAT1 expression levels and cell type patterns in the substantia nigra (SN) from 53 donors with and without PD, as well as in interference tissue culture tests followed by multiple in‐house and web‐available models of PD. PCR quantification identified elevated levels of NEAT1 expression in the PD SN compared with control brains, an elevation that was reproducible across a multitude of disease models. In situ RNA hybridization supported neuron‐specific formation of NEATl‐based para‐speckles at the SN and demonstrated coincreases of NEAT1 and paraspeckles in cultured cells under paraquat (PQ)‐induced oxidative stress. Furthermore, neuroprotective agents, including fenofibrate and simvastatin, induced NEAT1 up‐regulation, whereas RNA interference—mediated depletion of NEAT1 exacerbated death of…

The hypoglycemic effect of Phellinus linteus polysaccharide extract (PLPE) has been documented in several previous studies, but the functional interactions among PLPE, gut microbiota, and the hypoglycemic effect remain unclear. We examined the regulatory effect of PLPE on gut microbiota, and the molecular mechanism underlying improvement of insulin resistance, using a type 2 diabetic rat model. Here, 24 male Sprague-Dawley rats were randomly divided into four groups that were subjected to intervention of saline (normal and model control group), metformin (120 mg/kg.bw), and PLPE (600 mg/kg.bw) by oral administration. After 8 weeks of treatment, PLPE increased levels of short-chain fatty acids (SCFAs) by enhancing abundance of SCFA-producing bacteria. SCFAs maintained intestinal barrier function and reduced lipopolysaccharides content in blood, thereby helping to reduce systemic inflammation and reverse insulin resistance. Our findings suggest that PLPE (in which polysaccharides are the major component) has potential application as a prebiotic for regulating gut microbiota…

Chemotherapy resistance is one of the most common causes of death among patients with ovarian cancer, and identifying novel antitumor agents is a priority. Here, we report that the novel molecule 2‐(anaphthoyl)ethyl‐trimethylammonium iodide (α‐NETA) induces epithelial ovarian cancer (EOC) cell pyroptosis through the gesdermin‐d (GSDMD)/caspase‐4 pathway. Furthermore, Cell Counting Kit‐8 fluorescence‐activated cell sorting analysis showed that α‐NETA treatment led to cell death in different ovarian cancer cell lines, including Ho8910, Ho8910PM, and A2780. Morphologic examination by electron microscopy indicated that cells treated with α‐NETA produced multiple microbubbles, typical of cells undergoing pyroptosis. α‐NETA also significantly increased expression of pyroptosis‐associated molecules including caspase‐4 and GSDMD in EOC cells. Knockdown of either caspase‐4 or GSDMD in ovarian cancer cells strongly interfered with α‐NETA cell‐killing activity, indicating that α‐NETA acts through the pyroptosis pathway. In vivo , α‐NETA treatment dramatically decreased the size of EOC tumors…

Abstract Inflammation‐resolution is mediated by the balance between specialized pro‐resolving mediators (SPMs) like resolvin D1 (RvD1) and pro‐inflammatory factors, like leukotriene B 4 (LTB 4 ). A key cellular process of inflammation‐resolution is efferocytosis. Aging is associated with defective inflammation‐resolution and the accumulation of pro‐inflammatory senescent cells (SCs). Therefore, understanding mechanism(s) that underpin this impairment is a critical gap. Here, using a model of hind limb ischemia‐reperfusion (I/R) remote lung injury, we present evidence that aging is associated with heightened inflammation, impaired SPM:LT ratio, defective efferocytosis, and a decrease in MerTK levels in injured lungs. Treatment with RvD1 mitigated I/R lung injury in aging, promoted efferocytosis, and prevented the decrease of MerTK in injured lungs from old mice. Old MerTK cleavage‐resistant mice (MerTK CR ) exhibited less neutrophils or polymorpho nuclear cells infiltration and had improved efferocytosis compared with old WT controls. Mechanistically, macrophages that were treated…

Butyrate is a short‐chain fatty acid derived from the metabolism of indigestible carbohydrates by the gut microbiota. Butyrate contributes to gut homeostasis, but it may also control inflammatory responses and host physiology in other tissues. Butyrate inhibits histone deacetylases, thereby affecting gene transcription, and also signals through the metabolite‐sensing G protein receptor (GPR)109a. We produced an mAb to mouse GPR109a and found high expression on podocytes in the kidney. Wild‐type and Gpr109a –/– mice were induced to develop nephropathy by a single injection of Adriamycin and treated with sodium butyrate or high butyrate‐releasing high‐amylose maize starch diet. Butyrate improved proteinuria by preserving podocyte at glomerular basement membrane and attenuated glomerulosclerosis and tissue inflammation. This protective phenotype was associated with increased podocyte‐related proteins and a normalized pattern of acetylation and methylation at promoter sites of genes essential for podocyte function. We found that GPR109a is expressed by podocytes, and the use of Gpr109a…

ABSTRACT Diabetes nephropathy (DN) is characterized by abnormal interactions between kidney‐infiltrating macrophages and glomerular mesangial cells. Recently, a novel cell‐cell communication mediated by exosomes has gained attention. Exosomes are membrane‐bound vesicles that contain a variety of molecules such as proteins, lipids, DNA, mRNA, and microRNAs. Exosomes play an important role in the pathogenesis of DN. In this study, we show that high glucose (HG) led to increased excretion of exosomes from macrophages. Mesangial cells took up exosomes in vitro , which resulted in the activation and proliferation of mesangial cells and the secretion of extracellular matrix and inflammatory cytokines. In addition, C57BL/6 mice injected with exosomes from HG‐treated macrophages showed morphologic and functional changes. We then showed that exosomes from HG‐treated TGF‐β1 knockdown macrophages induced less extracellular matrix and fewer inflammatory factors in mesangial cells compared with vector control. Our findings suggest that TGF‐β1 mRNA in exosomes serves a role between macrophages…

Background: Sepsis is defined as a life-threatening organ dysfunction caused by a dysregulated host response to microbial infection. For decades, the gut microbiota was thought to play an important role in sepsis pathogenesis. However, the systemic and functional link between gut microbiota and sepsis has remained unexplored. Methods: To address this gap in knowledge, for the first time, we carried out systematic analyses on clinical stool samples from septic patients, including 16S rDNA sequencing, metabolomics and metaproteomics analyses. In addition, we performed fecal microbiota transplantation from human to mice to validate the roles of gut microbiota in sepsis progression. Findings: We found the composition of gut microbiota was significantly disrupted in septic patients compared with healthy individuals. Besides, the microbial functions were significantly altered in septic feces as identified by metabolomics and metaproteomics analyses. Interestingly, mice that received septic feces exhibited more severe hepatic inflammation and injury than mice that received healthy feces…

In hypertrophic scar (HS) formation, the type 2 immune response induces the alternatively activated macrophages (M2), which manipulate fibroblasts to differentiate into myofibroblasts with active biologic functions and proliferation. Myofibroblasts express α‐smooth muscle actin (α‐SMA) and synthesize and produce additional collagen type I and collagen type III, inducing HS formation. However, studies on the mechanism of M2 macrophage modulation are only based on the recognition of profibrotic factors such as TGF‐β1 secreted by macrophages. The influence of exosomes from M2 macrophages on scar formation is still unknown. Both M2 macrophages and myofibroblasts highly express glutaminases (GLSs). GLS is a critical enzyme in glutaminolysis and is important for M2 macrophage and fibroblast polarization. In this study, we found that in a TGF‐β1‐stimulated coculture system, a long noncoding RNA (lncRNA) named lncRNA‐ASLNCS5088 was enriched in M2 macrophage‐derived exosomes. This lncRNA could be transferred with high efficiency to fibroblasts and acted as an endogenous sponge to adsorb…

While great interest in health effects of natural product (NP) including dietary supplements and foods persists, promising preclinical NP research is not consistently translating into actionable clinical trial (CT) outcomes. Generally considered the gold standard for assessing safety and efficacy, CTs, especially phase III CTs, are costly and require rigorous planning to optimize the value of the information obtained. More effective bridging from NP research to CT was the goal of a September, 2018 transdisciplinary workshop. Participants emphasized that replicability and likelihood of successful translation depend on rigor in experimental design, interpretation, and reporting across the continuum of NP research. Discussions spanned good practices for NP characterization and quality control; use and interpretation of models (computational through in vivo) with strong clinical predictive validity; controls for experimental artefacts, especially for in vitro interrogation of bioactivity and mechanisms of action; rigorous assessment and interpretation of prior research; transparency in…

Neuron-derived exosomes (NDEs) were enriched by anti-L1CAM antibody immunoabsorption from plasmas of subjects ages 18-26 yr within 1 wk after a sports-related mild traumatic brain injury (acute mTBI) ( n = 18), 3 mo or longer after the last of 2-4 mTBIs (chronic mTBI) ( n = 14) and with no recent history of TBI (controls) ( n = 21). Plasma concentrations of NDEs, assessed by counts and levels of extracted exosome marker CD81, were significantly depressed by a mean of 45% in acute mTBI ( P < 0.0001), but not chronic mTBI, compared with controls. Mean CD81-normalized NDE levels of a range of functional brain proteins were significantly abnormal relative to those of controls in acute but not chronic mTBI, including ras-related small GTPase 10, 73% decrease; annexin VII, 8.8-fold increase; ubiquitin C-terminal hydrolase L1, 2.5-fold increase; AII spectrin fragments, 1.9-fold increase; claudin-5, 2.7-fold increase; sodium-potassium-chloride cotransporter-1, 2.8-fold increase; aquaporin 4, 8.9-fold increase (3.6-fold increase in chronic mTBI); and synaptogyrin-3, 3.1-fold increase…

Streptococcus pneumoniae is a major cause of community-acquired pneumonia leading to high mortality rates. Inflammation triggered by pneumococcal infection is necessary for bacterial clearance but must be spatially and temporally regulated to prevent further tissue damage and bacterial dissemination. Annexin A1 (AnxA1) mainly acts through Formyl Peptide Receptor 2 (FPR2) inducing the resolution of inflammation. Here, we have evaluated the role of AnxA1 and FPR2 during pneumococcal pneumonia in mice. For that, AnxA1, Fpr2/3 knockout (KO) mice and wild-type (WT) controls were infected intranasally with S pneumoniae. AnxA1 and Fpr2/3 KO mice were highly susceptible to infection, displaying uncontrolled inflammation, increased bacterial dissemination, and pulmonary dysfunction compared to WT animals. Mechanistically, the absence of AnxA1 resulted in the loss of lung barrier integrity and increased neutrophil activation upon S pneumoniae stimulation. Importantly, treatment of WT or AnxA1 KO-infected mice with Ac2-26 decreased inflammation, lung damage, and bacterial burden in the airways…

ABSTRACT Dietary methionine restriction (MR) is well known to reduce body weight by increasing energy expenditure (EE) and insulin sensitivity. An elevated concentration of circulating fibroblast growth factor 21 (FGF21) has been implicated as a potential underlying mechanism. The aims of our study were to test whether dietary MR in the context of a high‐fat regimen protects against type 2 diabetes in mice and to investigate whether vegan and vegetarian diets, which have naturally low methionine levels, modulate circulating FGF21 in humans. New Zealand obese (NZO) mice, a model for polygenic obesity and type 2 diabetes, were placed on isocaloric high‐fat diets (protein, 16 kcal%; carbohydrate, 52 kcal%; fat, 32 kcal%) that provided methionine at control (Con; 0.86% methionine) or low levels (0.17%) for 9 wk. Markers of glucose homeostasis and insulin sensitivity were analyzed. Among humans, low methionine intake and circulating FGF21 levels were investigated by comparing a vegan and a vegetarian diet to an omnivore diet and evaluating the effect of a short‐term vegetarian diet on…

Cancer cachexia is a multifactorial syndrome characterized by anorexia, body wasting, and muscle and adipose tissue loss, impairing patient's tolerance to anticancer treatments and survival. The aim of the present study was to compare the effects induced in mice by tumor growth alone (C26) or in combination with chemotherapy [C26 oxaliplatin and 5-fluorouracil (oxfu)] and to evaluate the potential of moderate exercise. Oxfu administration to C26 mice exacerbated muscle wasting and triggered autophagy or mitophagy, decreased protein synthesis, and induced mitochondrial alterations. Exercise in C26 oxfu mice counteracted the loss of muscle mass and strength, partially rescuing autophagy and mitochondrial function. Nevertheless, exercise worsened survival in C26 oxfu mice in late stages of cachexia. In summary, chemotherapy further impinges on cancer-induced alterations, worsening muscle wasting. An ideal multifactorial and early intervention to prevent cancer cachexia could take advantage of exercise, improving patient's energy metabolism, mobility, and quality of life.-Ballarò, R.,…

Although a high marine food intake is considered cardioprotective, randomized trials of ω-3 fatty acids initially generated conflicting results in terms of the role of ω-3 supplementation in cardiovascular prevention. This work demonstrates the results of the 3 most recent clinical trials with ω-3 fatty acids are put into the context of possible mechanisms mediating their beneficial cardiovascular effects. In particular, the randomized Reduction of Cardiovascular Events with EPA Intervention Trial (REDUCE-IT) showed that icosapent ethyl, which is the ethyl ester form of the ω-3 fatty acid eicosapentaenoic acid (EPA), induced a significant reduction of cardiovascular events. Importantly, EPA serves as a substrate for the formation of the specialized proresolving mediator resolvin E1 (RvE1), which stimulates the resolution of inflammation. RvE1 reduces atherosclerosis and intimal hyperplasia by means of its specific receptor ERV1/ChemR23. The decreased levels of proinflammatory and proatherosclerotic leukotrienes by ω-3 fatty acids may further contribute to a beneficial inflammatory…

Sirtuins (Sirts) are implicated in regulating a myriad of biologic functions ranging from cell growth and metabolism to longevity. Here, we show that nuclear Sirt, Sirt6, and mitochondrial Sirt, Sirt3, regulate each other's activity and protect the heart from developing diabetic cardiomyopathy. We found that expression of both Sirt6 and Sirt3 was reduced in cardiomyocytes treated with palmitate and in hearts of mice fed with a high-fat, high-sucrose (HF-HS) diet to develop obesity and diabetes. Conversely, whole-body overexpressing Sirt6 transgenic (Tg.Sirt6) mice were protected from developing obesity and insulin resistance when fed with the same HF-HS diet. The hearts of Tg.Sirt6 mice were also protected from mitochondrial fragmentation and decline of Sirt3, resulting otherwise from HF-HS diet feeding. Mechanistic studies showed that Sirt3 preserves Sirt6 levels by reducing oxidative stress, whereas Sirt6 maintains Sirt3 levels by up-regulating nuclear respiratory factor 2 (Nrf2)-dependent Sirt3 gene transcription. We found that Sirt6 regulates Nrf2-mediated cardiac gene…

ABSTRACT The microbiome is increasingly implicated in immune regulation and mortality from sepsis. Mice with identical genetic backgrounds but distinct microbiomes were obtained from different vendors and analyzed following cecal ligation and puncture (CLP), β diversity of the microbiome measured from feces demonstrated significant differences between The Jackson Laboratory (Jax; Bar Harbor, ME, USA) and Charles River Laboratories (CR; Wilmington, MA, USA) C57/B6 mice. Jax mice had 7‐d mortality of 90% following CLP, whereas CR mice had a mortality of 53%. Differences in vendor were associated with altered immunophenotype with increased splenic IFN‐γ + CD4 + T cells, effector memory CD4 + T cells, and central memory CD4 + T cells and increased Peyer's patch effector memory CD4 + T cells in septic CR mice. To determine whether differences in the microbiome were responsible for these differences, Jax and CR mice were cohoused for 3 wk, after which they assumed a similar microbiota composition. Cohoused mice had improved survival following CLP compared to Jax mice and had similar…

Histone deacetylases 3 (HDAC3) modulates the acetylation state of histone and non-histone proteins and could be a powerful regulator of the inflammatory process in stroke. Inflammasome activation is a ubiquitous but poorly understood consequence of acute ischemic stroke. Here, we investigated the potential contributions of HDAC3 to inflammasome activation in primary cultured microglia and experimental stroke models. In this study, we documented that HDAC3 expression was increased in microglia of mouse experimental stroke model. Intraperitoneal injection of RGFP966 (a selective inhibitor of HDAC3) decreased infarct size and alleviated neurological deficits after the onset of middle cerebral artery occlusion (MCAO). In vitro data indicated that LPS stimulation evoked a time-dependent increase of HDAC3 and absent in melanoma 2 (AIM2) inflammasome in primary cultured microglia. Interestingly, AIM2 was subjected to spatiotemporal regulation by RGFP966. The ability of RGFP966 to inhibit the AIM2 inflammasome was confirmed in an experimental mouse model of stroke. As expected, AIM2…

tRNA‐derived fragments (tRFs) have been defined as a novel class of small noncoding RNAs. tRFs have been reported to be deregulated in cancer, but their biologic function remains to be fully understood. We have identified a new tRF (named tRF3E), derived from mature tRNA Glu , that is specifically expressed in healthy mammary glands but not in breast cancer (BC). Consistently, tRF3E levels significantly decrease in the blood of patients with epidermal growth factor receptor 2 (HER2)‐positive BC reflecting tumor status (control > early cancer > meta‐static cancer). tRF3E down‐regulation was recapitulated in Δ16HER2 transgenic mice, representing a BC preclinical model. Pulldown assays, used to search for proteins capable to selectively bind tRF3E, have shown that this tRF specifically interacts with nucleolin (NCL), an RNA‐binding protein overexpressed in BC and able to repress the translation of p53 mRNA. The binding properties of NCL‐tRF3E complex, predicted in silico and analyzed by EMSA assays, are congruent with a competitive displacement of p53 mRNA by tRF3E, leading to an…

Variants in the gene encoding the triggering receptor expressed on myeloid cells 2 (TREM2) are known to increase the risk of developing Alzheimer disease and Parkinson's disease (PD). However, the potential role of TREM2 effect on synucleinopathy has not been characterized. In this study, we investigated whether loss of TREM2 function affects α‐synucleinopathy both in vitro and in vivo. In vitro , BV2 microglial cells were exposed to α‐synuclein (α‐syn) in the presence or absence of TREM2 small interference RNA. For in vivo studies, wild‐type controls and TREM2 gene knockout mice were intracranially injected in the substantia nigra with adeno‐associated viral vectors expressing human α‐syn (AAV‐SYN) to induce PD. Our results revealed that knockdown of TREM2 aggravated α‐syn‐induced inflammatory responses in BV2 cells and caused greater apoptosis in SH‐SY5Y cells treated with BV2‐conditioned medium. In mice, TREM2 knockout exacerbated dopaminergic neuron loss in response to AAV‐SYN. Moreover, both in vitro and in vivo TREM2 deficiency induced a shift from an anti‐inflammatory toward…

Bone marrow-derived mesenchymal stem cells (BMSCs) have been recently reported to play a variety of vital roles in organ and tissue damage repair, mainly via potent paracrine activity, including secreting extracellular vesicles, such as exosomes, that serve as mediators facilitating intercellular communication and reprogramming recipient cells by delivering their contents to target cells. However, the underlying mechanisms are diverse and complex, and the influencing characteristics have rarely been studied. Accordingly, we designed this study to explore the time dependence of the effects of exosomes derived from BMSCs (BMexos) on renal ischemia-reperfusion (I/R) injury and the underlying mechanisms associated with the reperfusion time. Impressively, our study is the first to find that BMexos protected against renal I/R injury in vitro and in vivo at the very early reperfusion stages, especially 4-8 h after reperfusion in vitro and 8-16 h after reperfusion in vivo. Interestingly, we simultaneously found that endoplasmic reticulum (ER) stress was significantly suppressed following…

ABSTRACT Emerging evidence indicates that Ca 2+ is a vital factor in modulating the pathogenesis of Alzheimer's disease (AD). In healthy neurons, Ca 2+ concentration is balanced to maintain a lower level in the cytosol than in the extracellular space or certain intracellular compartments such as endoplasmic reticulum (ER) and the lysosome, whereas this homeostasis is broken in AD. On the plasma membrane, the AD hallmarks amyloid‐β (Aβ) and tau interact with ligand‐gated or voltage‐gated Ca 2+ ‐influx channels and inhibit the Ca 2+ ‐efflux ATPase or exchangers, leading to an elevated intracellular Ca 2+ level and disrupted Ca 2+ signal. In the ER, the disabled presenilin “Ca 2+ leak” function and the direct implications of Aβ and presenilin mutants contribute to Ca 2+ ‐signal disorder. The enhanced ryanodine receptor (RyR)—mediated and inositol 1,4,5‐trisphosphate receptor (IP 3 R)—mediated Ca 2+ release from the ER aggravates cytosolic Ca 2+ disorder and triggers apoptosis; the down‐regulated ER Ca 2+ sensor, stromal interaction molecule (STIM), alleviates store‐operated Ca 2+ entry…

Myosteatosis is the pathologic accumulation of lipid that can occur in conjunction with atrophy and fibrosis following skeletal muscle injury. Little is known about the mechanisms by which lipid accumulates in myosteatosis, but many clinical studies have demonstrated that the degree of lipid infiltration negatively correlates with muscle function and regeneration. Our objective was to determine the pathologic changes that result in lipid accumulation in injured muscle fibers. We used a rat model of rotator cuff injury in this study because the rotator cuff muscle group is particularly prone to the development of myosteatosis after injury. Muscles were collected from uninjured controls or 10, 30, or 60 d after injury and analyzed using a combination of muscle fiber contractility assessments, RNA sequencing, and undirected metabolomics, lipidomics, and proteomics, along with bioinformatics techniques to identify potential pathways and cellular processes that are dysregulated after rotator cuff tear. Bioinformatics analyses indicated that mitochondrial function was likely disrupted…

ABSTRACT Generalized pustular psoriasis (GPP) is a rare and severe inflammatory skin disease that can be life‐threatening. Gene mutations are found in some cases, but its immune pathogenesis is largely unknown. Here, we observed that the neutrophil:lymphocyte ratio in patients with GPP was higher than that in healthy controls and decreased after effective treatment. Neutrophils isolated from patients with GPP induced higher expressions of inflammatory genes including IL‐1β, IL‐36G, IL‐18, TNF‐α , and C‐X‐C motif chemokine ligands in keratinocytes than normal neutrophils did. Moreover, neutrophils from patients with GPP secreted more exosomes than controls, which were then rapidly internalized by keratinocytes, increasing the expression of these inflammatory molecules via activating NF‐κB and MAPK signaling pathways. The proteomic profiles in neutrophil exosomes further characterized functional proteins and identified olfactomedin 4 as the critical differentially expressed protein that mediates the autoimmune inflammatory responses of GPP. These results demonstrate that neutrophil…

Transforming growth factor-beta (TGFβ) is an enigmatic protein with various roles in healthy tissue homeostasis/development as well as the development or progression of cancer, wound healing, fibrotic disorders, and immune modulation, to name a few. As TGFβ is causal to various fibroproliferative disorders featuring localized or systemic tissue/organ fibrosis as well as the activated stroma observed in various malignancies, characterizing the pathways and players mediating its action is fundamental. In the current study, we found that TGFβ induces the expression of the immunoinhibitory molecule Programed death-ligand 1 (PD-L1) in human and murine fibroblasts in a Smad2/3- and YAP/TAZ-dependent manner. Furthermore, PD-L1 knockdown decreased the TGFβ-dependent induction of extracellular matrix proteins, including collagen Iα1 (colIα1) and alpha-smooth muscle actin (α-SMA), and cell migration/wound healing. In addition to an endogenous role for PD-L1 in profibrotic TGFβ signaling, TGFβ stimulated-human lung fibroblast-derived PD-L1 into extracellular vesicles (EVs) capable of…

Historically neurodegenerative diseases, Alzheimer's disease (AD) in particular, have been viewed to be primarily caused and driven by neuronal mechanisms. Very recently, due to experimental, genetic, and epidemiologic evidence, immune mechanisms have entered the central stage and are now believed to contribute significantly to risk, onset, and disease progression of this class of disorders. Although immune activation of microglial cells may over time engage various signal transduction pathways, inflammasome activation, which represents a canonical and initiating pathway, seems to be one of the first responses to extracellular β-amyloid (Aβ) accumulation. Here we review the current understanding of inflammasome activation in AD.-Venegas, C., Heneka, M. T. Inflammasome-mediated innate immunity in Alzheimer's disease.

Activation of platelets and neutrophils in septic shock results in the formation of microvascular clots containing an intricate scaffold of fibrin with neutrophil extracellular traps (NETs) DNA. NETs contain multiple components that might impact endogenous fibrinolysis, resulting in failure to lyse clots in the microcirculation and residual systemic microthrombosis. We propose herein that the reservoir of human neutrophil elastase (HNE) on NETs may directly interfere with the fibrinolytic mechanism via a plasminogen proteolytic pathway. To investigate this mechanism, we constructed fibrin‐NETs matrices by seeding and activating neutrophils onto a fibrin surface and monitored plasminogen activation or degradation. We demonstrate that the elastase activity of HNE‐DNA complexes is protected from inhibition by plasma antiproteases and sustains its ability to degrade plasminogen. Using mass spectrometry proteomic analysis, we identified plasminogen fragments composed of kringle (K) domains (K 1+2+3 , k 1+2+3+4 ) and the serine protease (SP) region (K 5 ‐SP). We further demonstrate that…

Recent data suggested a causative role of uric acid (UA) in the development of renal disease, in which endothelial dysfunction is regarded as the key mechanism. Endothelial‐to‐mesenchymal transition (EndoMT) and shedding of the glycocalyx are early changes of endothelial dysfunction. We investigated whether UA induced EndoMT in HUVECs and an animal model of hyperuricemia fed with 2% oxonic acid for 4 wk. UA induced EndoMT in HUVECs with a generation of reactive oxygen species via the activation of membranous NADPH oxidase (from 15 min) and mitochondria (from 6 h) along with glycocalyx shedding (from 6 h), which were blocked by probenecid. GM6001, an inhibitor of matrix metalloproteinase, alleviated UA‐induced glycocalyx shedding and EndoMT. Antioxidants including N ‐acetyl cysteine, apocynin, and mitotempo ameliorated EndoMT; however, they did not change glycocalyx shedding in HUVECs. In the kidney of hyperuricemic rats, endothelial staining in peritubular capillaries (PTCs) was substantially decreased with a de novo expression of α‐smooth muscle actin in PTCs. Plasma level of…

Cells of the adult nucleus pulposus (NP) are critically important in maintaining overall disc health and function. NP cells reside in a soft, gelatinous matrix that dehydrates and becomes increasingly fibrotic with age. Such changes result in physical cues of matrix stiffness that may be potent regulators of NP cell phenotype and may contribute to a transition toward a senescent and fibroblastic NP cell with a limited capacity for repair. Here, we investigate the mechanosignaling cues generated from changes in matrix stiffness in directing NP cell phenotype and identify mechanisms that can potentially preserve a biosynthetically active, juvenile NP cell phenotype. Using a laminin-functionalized polyethylene glycol hydrogel, we show that when NP cells form rounded, multicell clusters, they are able to maintain cytosolic localization of myocardin-related transcription factor (MRTF)-A, a coactivator of serum-response factor (SRF), known to promote fibroblast-like behaviors in many cells. Upon preservation of a rounded shape, human NP cells similarly showed cytosolic retention of…

Intracerebral hemorrhage (ICH) remains a devastating type of stroke that lacks an effective treatment. Recent evidence has demonstrated that CCL2 is involved in the blood-brain barrier (BBB) disruption and propagermanium (PG) as a CCL2 receptor inhibitor is neuroprotective in ischemic stroke. However, whether PG therapy exert effective role in acute ICH still unclear. In this study, our goal was to investigate the potential role of CCL2 and the effects of PG in ICH. Differentially expressed RNAs including CCL2 were detected in human ICH. CCL2 and the activation of p-p38 MAPK and AQP4 expression were analyzed in rats after ICH. Brain water content and BBB integrity as well as neurological function were also examined after PG administration. In addition, the mechanism by which CCL2-mediated BBB injury was further investigated by cell coculture. Our findings showed that PG could effectively reduce brain edema and improve neurobehavioral functions. p-p38 MAPK and AQP4 expression were significantly inhibited by PG in vivo and in vitro. To the best of our knowledge, this is the first…

Mumps virus (MuV) has high tropism to the testis and may lead to male infertility. Sertoli cells are the major targets of MuV infection. However, the mechanisms by which MuV infection impairs male fertility and Sertoli cell function remain unclear. The present study elucidated the effect of MuV infection on the blood‐testis barrier (BTB). The transepithelial electrical resistance of MuV‐infected mouse Sertoli cells was monitored, and the expression of major proteins of the BTB was examined. We demonstrated that MuV infection disrupted the BTB by reducing the levels of occludin and zonula occludens 1. Sertoli cells derived from Tlr2 –/– and Tnfa –/– mice were analyzed for mediating MuV‐induced impairment. TLR2‐mediated TNF‐α production by Sertoli cells in response to MuV infection impaired BTB integrity. MuV‐impaired BTB was not observed in Tlr2 –/– and Tnfa –/– Sertoli cells. Moreover, an inhibitor of TNF‐α, pomalidomide, prevents the disruption of BTB in response to MuV infection. FITC‐labeled biotin tracing assay confirmed that BTB permeability and spermatogenesis were transiently…

Accumulation of amyloid β (Aβ) peptide, inflammation, and oxidative stress contribute to Alzheimer's disease (AD) and trigger complex pathogenesis. The ketone body β-hydroxybutyrate (BHBA) is an endogenous metabolic intermediate that protects against stroke and neurodegenerative diseases, but the underlying mechanisms are unclear. The present study aims to elucidate the protective effects of BHBA in the early stage of AD model and investigate the underlying molecular mechanisms. Three-and-half-month-old double-transgenic mice (5XFAD) overexpressing β-amyloid precursor protein (APP) and presenilin-1 (PS1) were used as the AD model. The 5XFAD mice received 1.5 mmol/kg/d BHBA subcutaneously for 28 days. Morris water maze test, nest construction, and passive avoidance experiments were performed to assess the therapeutic effects on AD prevention in vivo, and brain pathology of 5XFAD mice including amyloid plaque deposition and microglia activation were assessed. Gene expression profiles in the cortexes of 5XFAD- and BHBA-treated 5XFAD mice were performed with high-throughput sequencing…

ABSTRACT Berberine (BBR) shows promising effects in the treatment of nonalcoholic fatty liver disease (NAFLD) by influencing various metabolic aspects. Inhibition of mitochondrial β‐oxidation (β‐OX) participates in the pathogenesis of NAFLD. Silent mating‐type information regulation 2 homolog 3 (SIRT3) has been reported to regulate mitochondrial β‐OX by deacetylating its substrate, long‐chain acyl—coenzyme A dehydrogenase (LCAD). This study aimed to explore whether BBR can promote mitochondrial β‐OX and the role of SIRT3 as well as the mechanisms underlying the effects of BBR on hepatic lipid metabolism in mice fed a high‐fat diet (HFD). BBR can significantly improve systematic and hepatic lipid metabolism in HFD‐fed mice. Metabolomics analysis revealed that β‐OX was inhibited in HFD‐induced mice, as indicated by the reduced production of short and medium carbon chain acylcarnitines, the activated form of free fatty acids, via β‐OX, which was reversed by BBR intervention. Exploration of the mechanism found that BBR intervention reversed the down‐regulation of SIRT3 and decreased the…

Metabolic reprogramming is a hallmark of cancer. Stromal cells could function as providers of energy metabolites for tumor cells by undergoing the "reverse Warburg effect," but the mechanism has not been fully elucidated. The interaction between the tumoral microvesicles (TMVs) and stroma in the tumor microenvironment plays a critical role in facilitating cancer progression. In this study, we demonstrated a novel mechanism for the TMV-mediated glycometabolic reprogramming of stromal cells. After being incubated with TMVs, normal human gingival fibroblasts exhibited a phenotype switch to cancer-associated fibroblasts and underwent a degradation of caveolin 1 (CAV1) through the ERK1/2-activation pathway. CAV1 degradation further induced the metabolic switch to aerobic glycolysis in the fibroblasts. The microvesicle-activated fibroblasts absorbed more glucose and produced more lactate. The migration and invasion of oral squamous cell carcinoma (OSCC) were promoted after being cocultured with the activated fibroblasts. Fibroblast-cancer cell glycometabolic coupling ring mediated by…

ABSTRACT Mitophagy has been implicated in mitochondrial quality control and in various human diseases. However, the study of in vivo mitophagy remains limited. We previously explored in vivo mitophagy using a transgenic mouse expressing the mitochondria‐targeted fluorescent protein Keima (mt‐Keima). Here, we generated mt‐Keima Drosophila to extend our efforts to study mitophagy in vivo . A series of experiments confirmed that mitophagy can be faithfully and quantitatively measured in mt‐Keima Drosophila . We also showed that alterations in mitophagy upon environmental and genetic perturbation can be measured in mt‐Keima Drosophila . Analysis of different tissues revealed a variation in basal mitophagy levels in Drosophila tissues. In addition, we found a significant increase in mitophagy levels during Drosophila embryogenesis. Importantly, loss‐of‐function genetic analysis demonstrated that the phosphatase and tensin homolog‐induced putative kinase 1 (PINK1)‐Parkin pathway is essential for the induction of mitophagy in vivo in response to hypoxic exposure and rotenone treatment.…

Balanced differentiation of mesenchymal stromal cells (MSCs) into osteoblasts and adipocytes is essential for healthy bone and fat homeostasis. A disturbed balance of MSC differentiation results in bone loss and increased adipogenesis as observed in several human conditions, such as osteoporosis, obesity, and aging. This reflects the importance of MSC fate decision. Therefore, it is important to identify factors that regulate the balance between osteogenic and adipogenic differentiation of MSCs so as to identify new targets to improve bone formation in osteoporosis and control adipose tissue development. There is accumulating evidence that thymus cell antigen 1 (Thy-1), also known as CD90, expressed on MSCs, plays a critical role in the fate decision of MSCs. Recently, Thy-1 has been shown to promote osteogenic differentiation of MSCs and thus bone formation while inhibiting adipogenic differentiation and restricting adipose tissue accumulation. The clinical importance of these findings was validated by the detection of reduced serum soluble Thy-1 in patients with disturbed bone…

Chronic activation of the IL‐1β system in adipose tissue on metabolic disorders is well demonstrated. However, a mechanism for its expression and activation in the tissue has remained unexplored. Here, we demonstrate that IL‐1β transcript was enriched in neutrophils of white adipose tissue (WAT) from lean mice. Mechanistically, the interaction of neutrophils with adipocytes induced IL‐1β expression via NF‐κB pathway. Lipolysis of adipocytes accumulated neutrophils prior to macrophages in WAT and produced high levels of IL‐1β via an inflammasome pathway. Leukotriene B 4 (LTB 4 ) production in WAT also contributed to neutrophil accumulation. Furthermore, an LTB 4 ‐inflammasome axis contributed to the expression of chemotactic molecules involved in high‐fat diet‐induced macrophage infiltration into WAT. We have identified previously unappreciated roles for neutrophils in the development of adipose tissue inflammation: robust IL‐1β production and infiltration of macrophages to initiate chronic inflammation.—Watanabe, Y., Nagai, Y., Honda, H., Okamoto, N., Yanagibashi, T., Ogasawara, M.,…

ABSTRACT Various studies demonstrate that long noncoding RNAs (IncRNAs) act as oncogenes or tumor suppressors in cancer. However, the function of IncRNAs in bladder cancer still remains largely unknown. In this study, we identified an IncRNA, gastric cancer–associated IncRNA1 (GClnc1), which was in high abundance in bladder cancer tissues and its expression was related to poor survival rates in patients with bladder cancer. In vitro and in vivo assays showed that GClnc1 significantly promoted cell proliferation, metastasis, and invasiveness in bladder cancer. Mechanistically, we first found that GClnc1 bound to LIN28B and promoted the expression of myelocytomatosis proto‐oncogene (MYC) through the LIN28B/let‐7a/MYC pathway. In short, GClnc1 is clinically, functionally, and mechanistically oncogenic in bladder cancer. GClnc1 may be a potential target for treating patients with bladder cancer.—Zhuang, C., Ma, Q., Zhuang, C., Ye, J., Zhang, F., Gui, Y. LncRNA GClnc1 promotes proliferation and invasion of bladder cancer through activation of MYC. FASEB J. 33, 11045–11059 (2019).…

ABSTRACT Hepatocellular carcinoma (HCC) is a common and deadly cancer with limited treatment options. Through genome‐wide growth depletion screens using clustered regularly interspaced short palindromic repeats and expression profiling of primary HCC tumors, we identified 13 clinically relevant target genes with therapeutic potential. Subsequent functional annotation analysis revealed significant enrichment of these 13 genes in the cell cycle, cell death, and survival pathways. Non–structural maintenance of chromosomes condensin I complex subunit G (NCAPG) was ranked the highest among the depletion screens and multiple HCC expression datasets. Transient inhibition of NCAPG using specific small interfering RNAs resulted in a significant reduction in cell growth, migration, and the down‐regulation of mitochondrial gene expression in vitro . Small homologous RNA–mediated knockdown of NCAPG significantly impaired cell viability, caused aberrant mitotic division, fragmented the mitochondrial network, and increased cell death in vitro . HCC cells with a reduced expression of NCAPG formed…

Abstract Ginsenoside Rg3 is one of the main constituents of Panax ginseng . Compelling evidence has demonstrated that ginsenoside Rg3 is capable of inhibiting inflammation. However, the mechanism mediating its anti‐inflammatory effects remain unclear. Here we show that ginsenoside Rg3 blocks IL‐1β secretion and caspase‐1 activation through inhibiting LPS priming and the NLRP3 inflammasome activation in human and mouse macrophages. Rg3 specifically inhibits activation of NLRP3 but not the NLRC4 or AIM2 inflammasomes. In addition, Rg3 has no effect on upstream regulation of NLRP3 inflammasome, such as K + efflux, ROS production, or mitochondrial membrane potential. Mechanistically, Rg3 abrogates NEK7‐NLRP3 interaction, and subsequently inhibits NLRP3‐ASC interaction, ASC oligomerization, and speckle formation. More importantly, Rg3 can reduce IL‐1β secretion induced by LPS in mice and protect mice from lethal endotoxic shock. Thus, our findings reveal an anti‐inflammatory mechanism for Rg3 and suggest its potential use in NLRP3‐driven diseases.

Abstract MTF1 is a conserved metal-binding transcription factor in eukaryotes that binds to conserved DNA sequence motifs, termed metal response elements (MREs). MTF1 responds to metal excess and deprivation, protects cells from oxidative and hypoxic stresses, and is required for embryonic development in vertebrates. We used multiple strategies to identify an unappreciated role for MTF1 and copper (Cu) in cell differentiation. Upon initiation of myogenesis from primary myoblasts, MTF1 expression increased, as did nuclear localization. Mtf1 knockdown impaired differentiation, while addition of non-toxic concentrations of Cu + enhanced MTF1 expression and promoted myogenesis. Cu + bound stoichiometrically to a C-terminus tetra-cysteine of MTF1. MTF1 bound to chromatin at the promoter regions of myogenic genes and binding was stimulated by copper. MTF1 formed a complex with MyoD at myogenic promoters, the master transcriptional regulator of the myogenic lineage. These studies establish novel mechanisms by which copper and MTF1 regulate gene expression in myoblast differentiation.

ABSTRACT The aim of the present study was to examine whether the immune‐modulatory bacteria Lactobacillus fermentum CECT5716 (LC40) ameliorates disease activity and cardiovascular complications in a female mouse model of lupus. Eighteen‐week‐old NZBWF1 [systemic lupus erythematosus (SLE)] and NZW/LacJ (control) mice were treated with vehicle or LC40 (5 × 10 8 colony‐forming units/d) for 15 wk. LC40 treatment reduced lupus disease activity, blood pressure, cardiac and renal hypertrophy, and splenomegaly in SLE mice. LC40 reduced the elevated T, B, regulatory T cells (T reg ), and T helper (T h )‐1 cells in mesenteric lymph nodes of lupus mice. LC40 lowered the higher plasma concentration of proinflammatory cytokines observed in lupus mice. Aortas from SLE mice showed reduced endothelium‐dependent vasodilator responses to acetylcholine. Endothelial dysfunction found in SLE is related to an increase of both NADPH oxidase‐driven superoxide production and eNOS phosphorylation at the inhibitory Thr 495 . These activities returned to normal values after a treatment with LC40. Probiotic…

Cachexia is frequently accompanied by severe metabolic derangements, although the mechanisms responsible for this debilitating condition remain unclear. Pyruvate dehydrogenase kinase (PDK)4, a critical regulator of cellular energetic metabolism, was found elevated in experimental models of cancer, starvation, diabetes, and sepsis. Here we aimed to investigate the link between PDK4 and the changes in muscle size in cancer cachexia. High PDK4 and abnormal energetic metabolism were found in the skeletal muscle of colon-26 tumor hosts, as well as in mice fed a diet enriched in Pirinixic acid, previously shown to increase PDK4 levels. Viral-mediated PDK4 overexpression in myotube cultures was sufficient to promote myofiber shrinkage, consistent with enhanced protein catabolism and mitochondrial abnormalities. On the contrary, blockade of PDK4 was sufficient to restore myotube size in C2C12 cultures exposed to tumor media. Our data support, for the first time, a direct role for PDK4 in promoting cancer-associated muscle metabolic alterations and skeletal muscle atrophy.-Pin, F., Novinger,…

Endometriosis is a chronic inflammatory, gynecological disease characterized by the presence of endometrial-like tissue lesions outside of the uterus. Neutrophils are elevated in the systemic circulation and peritoneal fluid of endometriosis patients; however, whether and how neutrophils contribute to endometriosis pathophysiology remain poorly understood. With emerging roles for neutrophils in chronic and sterile inflammatory conditions, we sought to provide in-depth characterization of neutrophil involvement in endometriosis. We demonstrate that neutrophils reside within patient endometriotic lesions and that patient lesions possess a microenvironment that may influence neutrophil recruitment and function. We also provide the first evidence that systemic circulating neutrophils from endometriosis patients display distinct transcriptomic differences compared neutrophils from healthy control subjects. Time course characterization of our syngeneic, immunocompetent mouse model of endometriosis revealed that neutrophils are rapidly recruited to the peritoneal environment early after…

ABSTRACT During tendon healing, it is postulated that tendon cells drive tissue regeneration, whereas extrinsic cells drive pathologic scar formation. Tendon cells are frequently described as a homogenous, fibroblast population that is positive for the marker Scleraxis (Scx). It is controversial whether tendon cells localize within the forming scar tissue during adult tendon healing. We have previously demonstrated that S100 calcium‐binding protein A4 (S100a4) is a driver of tendon scar formation and marks a subset of tendon cells. The relationship between Scx and S100a4 has not been explored. In this study, we assessed the localization of Scx lineage cells (Scx Lin ) following adult murine flexor tendon repair and established the relationship between Scx and S100a4 throughout both homeostasis and healing. We showed that adult Scx Lin localize within the scar tissue and organize into a cellular bridge during tendon healing. Additionally, we demonstrate that markers Scx and S100a4 label distinct populations in tendon during homeostasis and healing, with Scx found in the organized…

Mitochondrial quality control maintains mitochondrial function by regulating mitochondrial dynamics and mitophagy. Despite the identification of mitochondrial quality control factors, little is known about the crucial regulators coordinating both mitochondrial fission and mitophagy. Through a cell-based functional screening assay, FK506 binding protein 8 (FKBP8) was identified to target microtubule-associated protein 1 light chain 3 (LC3) to the mitochondria and to change mitochondrial morphology. Microscopy analysis revealed that the formation of tubular and enlarged mitochondria was observed in FKBP8 knockdown HeLa cells and the cortex of Fkbp8 heterozygote-knockout mouse embryos. Under iron depletion-induced stress, FKBP8 was recruited to the site of mitochondrial division through budding and colocalized with LC3. FKBP8 was also found to be required for mitochondrial fragmentation and mitophagy under hypoxic stress. Conversely, FKBP8 overexpression induced mitochondrial fragmentation in HeLa cells, human fibroblasts and mouse embryo fibroblasts (MEFs), and this fragmentation…

RNA-binding proteins like human antigen R (HuR) are key regulators in post-transcriptional control of gene expression in several pathophysiological conditions. Diabetes adversely affects monocyte/macrophage biology and function. It is not known whether diabetic milieu affects cellular/exosome-HuR and its implications on cardiac inflammation and fibrosis. Here, we evaluate in vitro and in vivo effects of diabetic milieu on macrophage cellular/exosome-HuR, alterations in intercellular cross talk with fibroblasts, and its impact on cardiac remodeling. Human failing hearts show higher HuR levels. Diabetic milieu activates HuR expression in cardiac- and cultured bone marrow-derived macrophages (BMMØ) and stimulates HuR nuclear-to-cytoplasmic translocation and exosome transfer. Exosomes from macrophages exposed to diabetic milieu (high glucose or db/db mice) significantly increase inflammatory and profibrogenic responses in fibroblast (in vitro) and cardiac fibrosis in mice. Intriguingly, Exo-HuR deficiency (HuR knockdown in macrophage) abrogates the above effects. In diabetic mice,…

Triggering receptor expressed in myeloid cells (TREM)2 is a genetic high-risk factor for sporadic Alzheimer's disease (AD) and is considered a potential target for AD diagnosis and therapy, although its role in the different stages of AD remains controversial. We generated an embryonic deletion of Trem2 (whole body deletion) and induced hippocampal- and cortical-specific knockdown of microglial Trem2 at different stages of the AD process in amyloid precursor protein/Psen1 mice by adeno-associated virus (AAV) infection. AAV infection induced microglial Trem2 overexpression in the hippocampus of wild-type (WT) and thymus cell antigen 1-enhanced green fluorescent protein mice. Mice were subjected to ethological and pathologic tests. Whole body genetic deletion of Trem2 exerted different electrophysiological outcomes between different AD pathologic stages, which results from a complex integration of synaptic loss and amyloid aggregation. Interestingly, knockdown of Trem2 at the early-middle stage of AD (2-6 mo) prevents synaptic loss through directly inhibiting microglial phagocytosis,…

ABSTRACT Schwann cells are the main supportive cells of the peripheral nerves. Schwann cells suffer inhibition of autophagy under hyperglycemia treatment in diabetic peripheral neuropathy (DPN). However, the exact mechanism is still not fully elucidated. We first observed the decrease of autophagy markers (LC3‐II/LC3‐I, P62) in the sciatic nerves of diabetic mice vs . normal mice, accompanied with the loss of myelinated nerve fibers and abnormal myelin sheath. In line with this, LC3‐II/LC3‐I and P62 were also significantly reduced in high glucose—treated rat Schwann cell 96 (RSC96) cells compared with normal glucose—treated cells. Furthermore, we found that trichostatin A [an inhibitor of histone deacetylase (HDAC)] evidently improved LC3‐II/LC3‐I in high glucose—treated RSC96 cells, without an effect on P62 expression. Again, HDAC1 and HDAC5 were revealed to be increased in RSC96 cells stimulated with high glucose. Inhibition of HDAC1 but not HDAC5 by small hairpin RNA vector enhanced LC3‐II/LC3‐I in high glucose—cultured RSC96 cells. In addition, LC3‐II conversion regulators…

Recombinant antimicrobial peptide microcin J25 (MccJ25) causes potent antimicrobial activity against enterotoxigenic Escherichia coli (ETEC) in vitro; however, independently of this activity, its role in suppressing intestinal inflammation and epithelial barrier injury in vivo remains unclear. We investigated the therapeutic effects of MccJ25 on intestinal inflammation and epithelial barrier dysfunction and the underlying mechanism, using gentamicin for comparison. In a mouse model of intestinal inflammation, therapeutic administration of either MccJ25 or gentamicin after ETEC K88 infection attenuated clinical symptoms, reduced intestinal pathogen colonization, improved intestinal morphology, and decreased inflammatory pathologies and intestinal permeability, ultimately improving the hosts' health. MccJ25 also attenuated ETEC-induced mouse intestinal barrier dysfunction by enhancing tight junction proteins (TJPs). Using the human epithelial cell line Caco-2, we verified the epithelial barrier-strengthening and mucosal injury-alleviating effects of MccJ25 on ETEC infection: increased…

The nuclear factor erythroid 2-related factor 2 (Nrf2) signaling axis is a target of covalent drugs and bioactive native electrophiles. However, much of our understanding of Nrf2 regulation has been focused at the protein level. Here we report a post-transcriptional modality to directly regulate Nrf2-mRNA. Our initial studies focused on the effects of the key mRNA-binding protein (mRBP) HuR on global transcriptomic changes incurred upon oxidant or electrophile stimulation. These RNA-sequencing data and subsequent mechanistic analyses led us to discover a novel role of HuR in regulating Nrf2 activity, and in the process, we further identified the related mRBP AUF1 as an additional novel Nrf2 regulator. Both mRBPs regulate Nrf2 activity by direct interaction with the Nrf2 transcript. Our data showed that HuR enhances Nrf2-mRNA maturation and promotes its nuclear export, whereas AUF1 stabilizes Nrf2-mRNA. Both mRBPs target the 3'-UTR of Nrf2-mRNA. Using a Nrf2 activity-reporter zebrafish strain, we document that this post-transcriptional control of Nrf2 activity is conserved at the…

Kidney fibrosis occurs in almost every type of chronic kidney disease. We found that microRNA (miR)-26a was decreased in the kidney, muscle, and exosomes of unilateral ureteral obstruction (UUO) mice. We hypothesized that exogenous miR-26 could suppresses renal fibrosis and muscle wasting in obstructive kidney disease. For this purpose, we generated exosomes that encapsulated miR-26, then injected these into skeletal muscle of UUO mice. The expression of miR-26a was elevated in serum exosomes from UUO mice following exosome-miR-26a injection. In these mice, muscle wasting has been ameliorated as evidenced by increased muscle weights. In addition, a muscle atrophy marker, myostatin, is increased in UUO muscle; provision of miR-26a abolished this increase. We detected a remote effect of exosomes containing miR-26a in UUO-induced renal fibrosis. The intervention of miR-26a attenuated UUO-induced renal fibrosis as determined by immunohistological assessment of α-smooth muscle actin and Masson's trichrome staining. Furthermore, exogenous miR-26a decreased the protein levels of 2…

The commensal microbiota is one of the environmental triggers of rheumatoid arthritis (RA). Recent studies have identified the characteristics of the gut microbiota in patients with RA. However, it is still unclear how the microbiota can be modulated to slow down disease progression. In the present study, berberine, a modulator of gut microbiota with substantial anti‐RA effect, was chosen to explore the mechanisms by which the microbiota modulators ameliorate RA. The results showed that oral administration of berberine alleviated collagen‐induced arthritis (CIA) in rats in a gut microbiota‐dependent manner. Berberine down‐regulated the diversity and richness of the gut bacteria, reduced the abundance of Prevotella , and elevated the abundance of butyrate‐producing bacteria in CIA rats as determined by the 16S rRNA gene sequence, which might function through limiting the generation of nitrate and stabilizing the physiologic hypoxia in the intestine. Moreover, berberine treatment significantly increased the intestinal butyrate level and promoted the expression and activity of…

The human gut is colonized by commensal microorganisms, predominately bacteria that have coevolved in symbiosis with their host. The gut microbiota has been extensively studied in recent years, and many important findings on how it can regulate host metabolism have been unraveled. In healthy individuals, feeding timing and type of food can influence not only the composition but also the circadian oscillation of the gut microbiota. Host feeding habits thus influence the type of microbe-derived metabolites produced and their concentrations throughout the day. These microbe-derived metabolites influence many aspects of host physiology, including energy metabolism and circadian rhythm. Peroxisome proliferator-activated receptors (PPARs) are a group of ligand-activated transcription factors that regulate various metabolic processes such as fatty acid metabolism. Similar to the gut microbiota, PPAR expression in various organs oscillates diurnally, and studies have shown that the gut microbiota can influence PPAR activities in various metabolic organs. For example, short-chain fatty…

ABSTRACT We recently described myonectin (also known as erythroferrone) as a novel skeletal muscle‐derived myokine with metabolic functions. Here, we use a genetic mouse model to determine myonectin's requirement for metabolic homeostasis. Female myonectin‐deficient mice had larger gonadal fat pads and developed mild insulin resistance when fed a high‐fat diet (HFD) and had reduced food intake during refeeding after an unfed period but were otherwise indistinguishable from wild‐type littermates. Male mice lacking myonectin, however, had reduced physical activity when fed ad libitum and in the postprandial state but not during the unfed period. When stressed with an HFD, myonectin‐knockout male mice had significantly elevated VLDL‐triglyceride (TG) and strikingly impaired lipid clearance from circulation following an oral lipid load. Fat distribution between adipose and liver was also altered in myonectin‐deficient male mice fed an HFD. Greater fat storage resulted in significantly enlarged adipocytes and was associated with increased postprandial lipoprotein lipase activity in…

Lysyl oxidases (LOXs) play a central role in extracellular matrix remodeling during development and tumor growth and fibrosis through cross-linking of collagens and elastin. We have limited knowledge of the structure and substrate specificity of these secreted enzymes. LOXs share a conserved C-terminal catalytic domain but differ in their N-terminal region, which is composed of 4 repeats of scavenger receptor cysteine-rich (SRCR) domains in LOX-like (LOXL) 2. We investigated by X-ray scattering and electron microscopy the low-resolution structure of the full-length enzyme and the structure of a shorter form lacking the catalytic domain. Our data demonstrate that LOXL2 has a rod-like structure with a stalk composed of the SRCR domains and the catalytic domain at its tip. We detected direct interaction between LOXL2 and tropoelastin (TE) and also LOXL2-mediated deamination of TE. Using proteomics, we identified several allysines together with cross-linked TE peptides. The elastin-like material generated was resistant to trypsin proteolysis and displayed mechanical properties similar…

Sodium valproate (VPA), an antiepileptic drug, may cause dose- and time-dependent hepatotoxicity. However, its iatrogenic molecular mechanism and the rescue therapy are disregarded. Recently, it has been demonstrated that sodium butyrate (NaB) reduces hepatic steatosis, improving respiratory capacity and mitochondrial dysfunction in obese mice. Here, we investigated the protective effect of NaB in counteracting VPA-induced hepatotoxicity using in vitro and in vivo models. Human HepG2 cells and primary rat hepatocytes were exposed to high VPA concentration and treated with NaB. Mitochondrial function, lipid metabolism, and oxidative stress were evaluated, using Seahorse analyzer, spectrophotometric, and biochemical determinations. Liver protection by NaB was also evaluated in VPA-treated epileptic WAG/Rij rats, receiving NaB for 6 months. NaB prevented VPA toxicity, limiting cell oxidative and mitochondrial damage (ROS, malondialdehyde, SOD activity, mitochondrial bioenergetics), and restoring fatty acid oxidation (peroxisome proliferator-activated receptor α expression and carnitine…

ABSTRACT Rac‐GTPases are major regulators of cytoskeletal remodeling and their deregulation contributes to numerous pathologies. Whether or how Rac promotes tubulointerstitial fibrosis and chronic kidney disease (CKD) is currently unknown. We showed that the major profibrotic cytokine, TGF‐β1 promoted rapid Rac1‐GTP loading in human kidney 2 (HK‐2) human renal epithelial cells. A Rac‐specific chemical inhibitor, EHT 1864, blocked TGF‐β1‐induced fibrotic reprogramming in kidney epithelial cells and fibroblasts. Stable Rac1 depletion in HK‐2 cells, moreover, eliminated TGF‐β1‐mediated non‐SMAD pathway activation [ e.g ., Src, epidermal growth factor receptor (EGFR), p53] and subsequent plasminogen activator inhibitor‐1 (PAI‐1), connective tissue growth factor, fibronectin, and p21 induction. Rac1 and p22 phox knockdown abrogated free radical generation by TGF‐β1 in HK‐2 cells, consistent with the role of Rac1 in NAPD(H). TGF‐β1‐induced renal epithelial cytostasis was also completely bypassed by Rac1, p22 phox , p47 phox , and PAI‐1 silencing. Rac1b isoform expression was robustly…

Nonalcoholic fatty liver disease (NAFLD) is one of the most prevalent diseases worldwide. Exercise is a first‐line therapy and an important preventive measure for patients with NAFLD, but the underlying mechanisms are not clear. C57BL/6 mice were fed a high‐fat diet (HFD) and subjected to 12 wk swimming exercise. Exercise protected against hepatic lipid accumulation and alleviated hepatocyte damage in HFD mice. Tandem mass tag—based quantitative proteomic analyses and ingenuity pathway analysis revealed that exercise down‐regulated fatty acid‐binding protein (FABP) 1 signaling pathway, which was most closely associated with lipid metabolism. Moreover, exercise significantly decreased FABP1 expression, and liver‐specific overexpression of FABP1 abolished the protective effect of exercise in NAFLD mice. Specifically, exercise significantly increased autophagic flux via restoring lysosomal function, including lysosomal proteolysis and lysosomal acidification maintenance, contributing to enhancement in autophagic clearance and subsequently alleviation of hepatic steatosis. Conversely,…

Bone fracture healing is a complex, dynamic process that involves various cell types, with osteoclasts and osteoblasts playing indispensable roles. In this study, we found that psoralen, the main active ingredient in Psoralea corylifolia L. fruit extract, enhanced bone fracture healing through activation of osteoclast and osteoblast activity via the ERK signaling pathway. In detail, psoralen promoted receptor activator of nuclear factor-κB ligand-induced osteoclastogenesis, mRNA expression of osteoclast-specific genes, and osteoclastic bone resorption in primary bone marrow-derived macrophages. Meanwhile, psoralen induced osteogenic differentiation by promoting the mRNA expression of the osteoblast differentiation markers alkaline phosphatase, runt-related transcription factor 2, osterix, and osteocalcin. At the molecular level, psoralen preferentially activated ERK1/2 but not JNK or p38 MAPKs. Further experiments revealed that psoralen-induced osteoclast and osteoblast differentiation was abrogated by a specific inhibitor of phosphorylated ERK. In addition, psoralen accelerated…

Activation of the NACHT, leucine-rich repeat, and pyrin domains-containing protein 3 (collectively known as NLRP3) inflammasome plays a key role in host immune response, which is the first line of defense against cellular stresses and pathogen infections. However, excessive inflammasome activation damages host cells, and therefore it must be precisely controlled. Here, we discover that Cullin1 (CUL1), a key component of the Skp1-Cullin1-F-box E3 ligase, plays a critical role in controlling the NLRP3 inflammasome. CUL1 represses inflammasome assembly in cultured cells, suppresses NLRP3 function in human monocytic cell line macrophages, and attenuates inflammatory responses in mouse model. Detailed studies demonstrate that CUL1 interacts with NLRP3 and promotes NLRP3 ubiquitination, but not protein degradation, to repress the NLRP3 inflammasome activation. Moreover, upon inflammatory stimuli, including ATP and nigericin treatments, CUL1 disassociates from NLRP3 to release the repression of the NLRP3 inflammasome. Thus, this study reveals a distinct and unique mechanism underlying the…

MicroRNAs (miRNAs) regulate gene expression posttranscriptionally and control biological processes (BPs), including fibrogenesis. Kidney fibrosis remains a clinical challenge and miRNAs may represent a valid therapeutic avenue. We show that miR-9-5p protected from renal fibrosis in the mouse model of unilateral ureteral obstruction (UUO). This was reflected in reduced expression of pro-fibrotic markers, decreased number of infiltrating monocytes/macrophages, and diminished tubular epithelial cell injury and transforming growth factor-beta 1 (TGF-β1)-dependent de-differentiation in human kidney proximal tubular (HKC-8) cells. RNA-sequencing (RNA-Seq) studies in the UUO model revealed that treatment with miR-9-5p prevented the downregulation of genes related to key metabolic pathways, including mitochondrial function, oxidative phosphorylation (OXPHOS), fatty acid oxidation (FAO), and glycolysis. Studies in human tubular epithelial cells demonstrated that miR-9-5p impeded TGF-β1-induced bioenergetics derangement. The expression of the FAO-related axis peroxisome proliferator-activated…

ABSTRACT Ischemic spinal cord injury (ISCI) results in the motor sensory dysfunction of the limbs below the injury site. In response to the injury, astrocytes develop into neuroprotective astrocytes [(neurotrophic reactive astrocytes (A2s)] to mitigate the damage. MicroRNA (miR)‐21 can promote the development of neuroinflammation in previous studies. Our aim was to investigate the effect of miR‐21 on its polarization. We used the abdominal aortic occlusion model in vivo . Immunohistochemistry was used to detect the distribution of A2s in the spinal cord. We used an oxygen glucose deprivation method to model astrocytes ischemia in vitro and tested proliferation, migration, and excitability of A2s using an 5‐ethynyl ‐2′‐deoxyuridine kit, wound scratch assay, and calcium‐ion probe. After adjustment, we detected the model and target genes of A2s using PCR Western blot, immunofluorescence, and chromatin immunoprecipitation. We demonstrated in vivo that naive astrocytes were transformed into A2s by ischemia. And in vitro miR‐21, which can regulate the signal transducer and activator of…

ABSTRACT Obesity increases the risk of developing insulin resistance and diabetes and is a major public health concern. Our previous study shows that dietary β‐hydroxy‐β‐methylbutyrate (HMB) improves lipid metabolism in a pig model. However, it remains unclear whether HMB blocks obesity through gut microbiota. In this study, we found that HMB reduced body weight, alleviated the whitening of brown adipose tissue, and improved insulin resistance in mice fed a high‐fat diet (HFD). High‐throughput pyrosequencing of the 16S rRNA demonstrated that HMB administration significantly reversed the gut microbiota dysbiosis in HFD‐fed mice, including the diversity of gut microbiota and relative abundances of Bacteroidetes and Firmicutes . Moreover, microbiota transplantation from HMB‐treated mice attenuated HFD‐induced lipid metabolic disorders. Furthermore, HFD‐fed mice showed lower short‐chain fatty acids, whereas administration of HMB increased the propionic acid production. Correlation analysis identified a significant correlation between propionic acid production and the relative…

Cellular senescence acts as an important barrier to tumorigenesis by eliminating precancerous cells. Previous studies have shown an essential role of the tumor suppressor p53 in cellular senescence, but how p53 induces cellular senescence is not fully understood. We found that p53 promoted the formation of highly interconnected and elongated mitochondria prior to the onset of cellular senescence. The inhibition of mitochondrial elongation upon p53 expression suppressed cellular senescence, suggesting that mitochondrial elongation is required for the induction of p53-dependent senescence. p53-induced mitochondrial elongation resulted in mitochondrial dysfunction and subsequent increases in intracellular reactive oxygen species (ROS) levels, an important mediator of cellular senescence. Mechanistically, the inhibitory phosphorylation of Drp1 Ser637 increased upon p53 expression, suppressing the translocation of Drp1 into mitochondria. The transcriptional function of p53 was crucial for controlling the inhibitory phosphorylation of Drp1, whereas p21 was nonessential. Protein kinase A…

Patients with chronic kidney disease (CKD) exhibit reduced exercise capacity, poor physical function and symptoms of fatigue. The mechanisms that contribute to this are not clearly defined but may involve reductions in mitochondrial function, mass and biogenesis. Here we report on the effect of non-dialysis dependent CKD (NDD-CKD) on mitochondrial mass and basal expression of transcription factors involved in mitochondrial biogenesis compared to a healthy control cohort (HC). In addition, we sought to investigate the effect of a 12-week exercise-training programme on these aspects of mitochondrial dysfunction in a NDD-CKD cohort.For the comparison between NDD-CKD and HC populations, skeletal muscle biopsies were collected from the vastus lateralis (VL) of n=16 non-dialysis dependent CKD patient's stage 3b-5 (NDD-CKD) and n=16 healthy controls matched for age, gender and physical activity (HC). To investigate the effect of exercise training, VL biopsies were collected from n=17 NDD-CKD patients before and after a 12-week exercise intervention that was comprised of aerobic exercise…

AMP-activated protein kinase (AMPK) is a central energy sensor and master regulator of energy homeostasis. AMPK not only elicits acute metabolic responses, but also promotes metabolic reprogramming and adaptions in the long-term through regulation of specific transcription factors/co-activators. We performed a whole-genome transcriptome profiling in wild-type and AMPK-deficient mouse embryonic fibroblasts (MEF) and primary hepatocytes that had been treated with two distinct classes of small-molecule AMPK activators, namely 5-aminoimidazole-4-carboxamide ribonucleotide (AICAR) or 991. This led to the identification of distinct compound-dependent gene expression signatures and to the discovery of several AMPK-regulated genes, including Flcn encoding a tumor suppressor and nutrient sensor folliculin (FLCN). Gene set enrichment and pathway analyses identified the lysosomal pathway and the associated transcription factor EB (TFEB) as key transcriptional mediator responsible for AMPK-dependent gene expression changes. AMPK-induced Flcn expression was abolished in TFEB/TFE3 double knockout…

Maslinic acid is a pentacyclic triterpenoid that is distributed in the peel of olives. Previous studies found that maslinic acid inhibited inflammatory response and antioxidant effects. We investigated whether maslinic acid ameliorates nonalcoholic fatty liver disease in mice with high‐fat‐diet (HFD)‐induced obesity and evaluated the regulation of lipogenesis in hepatocytes. Male C57BL/6 mice fed a normal diet or HFD (60% fat, w/w) were tested for 16 wk. After the fourth week, mice were injected intraperitoneally with maslinic acid for 12 wk. In another experiment, HepG2 cells were treated with oleic acid to induce lipid accumulation or maslinic acid to evaluate lipogenesis. Maslinic acid significantly reduced body weight compared with HFD‐fed mice. Maslinic acid reduced liver weight and liver lipid accumulation and improved hepatocyte steatosis. Furthermore, serum glucose, leptin, and free fatty acid concentrations significantly reduced, but the serum adiponectin concentration was higher, in the maslinic acid group than in the HFD group. In liver tissue, maslinic acid suppressed…

Abstract For protection from inhaled pathogens many strategies have evolved in the airways such as mucociliary clearance and cough. We have previously shown that protective respiratory reflexes to locally released bacterial bitter “taste” substances are most probably initiated by tracheal brush cells (BC). Our single‐cell RNA‐seq analysis of murine BC revealed high expression levels of cholinergic and bitter taste signaling transcripts ( Tas2r108 , Gnat3 , Trpm5 ). We directly demonstrate the secretion of acetylcholine (ACh) from BC upon stimulation with the Tas2R agonist denatonium. Inhibition of the taste transduction cascade abolished the increase in [Ca 2+ ] i in BC and subsequent ACh‐release. ACh‐release is regulated in an autocrine manner. While the muscarinic ACh‐receptors M3R and M1R are activating, M2R is inhibitory. Paracrine effects of ACh released in response to denatonium included increased [Ca 2+ ] i in ciliated cells. Stimulation by denatonium or with Pseudomonas quinolone signaling molecules led to an increase in mucociliary clearance in explanted tracheae that was…