1 542 126 ATP-CITRATE LYASE IS AN EPIGENETIC REGULATOR TO PROMOTE OBESITY-RELATED KIDNEY INJURY. OBESITY IS A LEADING CAUSE OF CHRONIC KIDNEY DISEASE (CKD), BUT HOW OBESITY PROMOTES RENAL INJURY REMAINS POORLY UNDERSTOOD. HERE WE SHOWED THAT ATP-CITRATE LYASE (ACL), AN ENZYME CONVERTING CITRATE TO ACETYL-COA, IS HIGHLY INDUCED IN THE KIDNEY OF OVERWEIGHT OR OBESE PATIENTS WITH CKD AND OB/OB BTBR MICE. ACL INDUCTION IS ASSOCIATED WITH INCREASED ECTOPIC LIPID ACCUMULATION (ELA), GLOMERULOSCLEROSIS, AND ALBUMINURIA. ACETYL-COA IS THE SUBSTRATE FOR DE NOVO LIPOGENESIS AS WELL AS FOR HISTONE ACETYLATION. BY RAISING ACETYL-COA CONCENTRATION ACL PROMOTES H3K9/14 AND H3K27 HYPERACETYLATION LEADING TO UP-REGULATION OF SEVERAL RATE-LIMITING LIPOGENIC ENZYMES AND FIBROGENIC FACTORS. ON THE OTHER HAND, THE EXCESS ACETYL-COA GENERATED AS A RESULT OF ACL INDUCTION PROVIDES THE SUBSTRATE FOR THESE LIPOGENIC ENZYMES TO DRIVE DE NOVO LIPOGENESIS LEADING TO ELA, A DETRIMENTAL EVENT TOWARD RENAL INJURY. IN MESANGIAL CELLS, ACL IS SYNERGISTICALLY INDUCED BY HIGH GLUCOSE, PALMITATE, AND TNF-ALPHA VIA NF-KAPPAB AND PKA PATHWAYS. UNDER THESE CONDITIONS, H3K9/14 AND H3K27 HYPERACETYLATION, AS WELL AS THE INDUCTION OF THE LIPOGENIC AND FIBROGENIC PROTEINS, ARE COMPLETELY BLOCKED IN THE PRESENCE OF AN ACL INHIBITOR. COLLECTIVELY, THESE DATA SUGGEST THAT ACL IS AN EPIGENETIC REGULATOR THAT PROMOTES RENAL ELA AND FIBROGENESIS LEADING TO RENAL INJURY IN OBESITY.-CHEN, Y., DEB, D. K., FU, X., YI, B., LIANG, Y., DU, J., HE, L., LI, Y. C. ATP-CITRATE LYASE IS AN EPIGENETIC REGULATOR TO PROMOTE OBESITY-RELATED KIDNEY INJURY. 2019 2 1536 29 DNA METHYLATION ENZYMES IN THE KIDNEYS OF MALE AND FEMALE BTBR OB/OB MICE. DIABETIC KIDNEY DISEASE (DKD) IS THE LEADING CAUSE OF THE END-STAGE RENAL DISEASE. RECENT STUDIES HAVE SHOWN THAT EPIGENETIC MODIFICATIONS CONTRIBUTE TO ALTERATIONS IN GENE EXPRESSION AND THE DEVELOPMENT OF DKD. THIS STUDY AIMED TO SHOW AN EXPRESSION PROFILE OF KEY DNA (DE)METHYLATION ENZYMES (DNMT, TET PROTEINS) AND THEIR DIFFERENCES BETWEEN SEXES UNDER OBESITY AND DIABETIC CONDITION. MALE AND FEMALE BLACK AND TAN BRACHYURY (BTBR) OB/OB MICE AND THEIR CORRESPONDING WILD-TYPE LITTERMATES (BTBR WT) WERE STUDIED UNTIL 16 WEEKS OF AGE. METABOLIC PARAMETERS, KIDNEY MORPHOPHYSIOLOGY AND THE EXPRESSION OF FIBROTIC MARKERS AND EPIGENETIC ENZYMES WERE STUDIED IN WHOLE KIDNEY TISSUE OR SPECIFICALLY IN THE GLOMERULUS. THE RESULTS SHOWED SEXUAL DIMORPHISM IN THE DEVELOPMENT OF METABOLIC DISEASE AND IN KIDNEY MORPHOPHYSIOLOGY. FEMALE MICE HAVE A DIFFERENT PROFILE OF DNMTS EXPRESSION IN BOTH WT AND OBESE/DIABETIC CONDITION. FURTHERMORE, METABOLIC CONDITION NEGATIVELY MODULATED THE GLOMERULAR EXPRESSION OF TET1 AND TET3 ONLY IN FEMALES. TO OUR KNOWLEDGE, THIS IS THE FIRST STUDY THAT SHOWS A KIDNEY PROFILE OF THE EXPRESSION OF KEY (DE)METHYLATION ENZYMES, DNMTS AND TETS, IN THE BTBR OB/OB EXPERIMENTAL MODEL OF DKD AND ITS ASSOCIATION WITH SEX. THE KNOWLEDGE OF THIS EPIGENETIC PROFILE MAY HELP FUTURE RESEARCH TO UNDERSTAND THE PATHOPHYSIOLOGY OF DKD IN MALES AND FEMALES. 2023 3 222 26 ACUTE LIVER STEATOSIS TRANSLATIONALLY CONTROLS THE EPIGENETIC REGULATOR MIER1 TO PROMOTE LIVER REGENERATION IN A STUDY WITH MALE MICE. THE EARLY PHASE LIPID ACCUMULATION IS ESSENTIAL FOR LIVER REGENERATION. HOWEVER, WHETHER THIS ACUTE LIPID ACCUMULATION CAN SERVE AS SIGNALS TO DIRECT LIVER REGENERATION RATHER THAN SIMPLY PROVIDING BUILDING BLOCKS FOR CELL PROLIFERATION REMAINS UNCLEAR. THROUGH IN VIVO CRISPR SCREENING, WE IDENTIFY MIER1 (MESODERM INDUCTION EARLY RESPONSE 1) AS A KEY EPIGENETIC REGULATOR THAT BRIDGES THE ACUTE LIPID ACCUMULATION AND CELL CYCLE GENE EXPRESSION DURING LIVER REGENERATION IN MALE ANIMALS. PHYSIOLOGICALLY, LIVER ACUTE LIPID ACCUMULATION INDUCES THE PHOSPHORYLATION OF EIF2S1(EUKARYOTIC TRANSLATION INITIATION FACTOR 2), WHICH CONSEQUENTLY ATTENUATED MIER1 TRANSLATION. MIER1 DOWNREGULATION IN TURN PROMOTES CELL CYCLE GENE EXPRESSION AND REGENERATION THROUGH CHROMATIN REMODELING. IMPORTANTLY, THE LIPIDS-EIF2S1-MIER1 PATHWAY IS IMPAIRED IN ANIMALS WITH CHRONIC LIVER STEATOSIS; WHEREAS MIER1 DEPLETION SIGNIFICANTLY IMPROVES REGENERATION IN THESE ANIMALS. TAKEN TOGETHER, OUR STUDIES IDENTIFY AN EPIGENETIC MECHANISM BY WHICH THE EARLY PHASE LIPID REDISTRIBUTION FROM ADIPOSE TISSUE TO LIVER DURING REGENERATION IMPACTS HEPATOCYTE PROLIFERATION, AND SUGGEST A POTENTIAL STRATEGY TO BOOST LIVER REGENERATION. 2023 4 5571 35 ROLE OF MICRORNA 1207-5P AND ITS HOST GENE, THE LONG NON-CODING RNA PVT1, AS MEDIATORS OF EXTRACELLULAR MATRIX ACCUMULATION IN THE KIDNEY: IMPLICATIONS FOR DIABETIC NEPHROPATHY. DIABETIC NEPHROPATHY IS THE MOST COMMON CAUSE OF CHRONIC KIDNEY FAILURE AND END-STAGE RENAL DISEASE IN THE WESTERN WORLD. ONE OF THE MAJOR CHARACTERISTICS OF THIS DISEASE IS THE EXCESSIVE ACCUMULATION OF EXTRACELLULAR MATRIX (ECM) IN THE KIDNEY GLOMERULI. WHILE BOTH ENVIRONMENTAL AND GENETIC DETERMINANTS ARE RECOGNIZED FOR THEIR ROLE IN THE DEVELOPMENT OF DIABETIC NEPHROPATHY, EPIGENETIC FACTORS, SUCH AS DNA METHYLATION, LONG NON-CODING RNAS, AND MICRORNAS, HAVE ALSO RECENTLY BEEN FOUND TO UNDERLIE SOME OF THE BIOLOGICAL MECHANISMS, INCLUDING ECM ACCUMULATION, LEADING TO THE DISEASE. WE PREVIOUSLY FOUND THAT A LONG NON-CODING RNA, THE PLASMACYTOMA VARIANT TRANSLOCATION 1 (PVT1), INCREASES PLASMINOGEN ACTIVATOR INHIBITOR 1 (PAI-1) AND TRANSFORMING GROWTH FACTOR BETA 1 (TGF-BETA1) IN MESANGIAL CELLS, THE TWO MAIN CONTRIBUTORS TO ECM ACCUMULATION IN THE GLOMERULI UNDER HYPERGLYCEMIC CONDITIONS, AS WELL AS FIBRONECTIN 1 (FN1), A MAJOR ECM COMPONENT. HERE, WE REPORT THAT MIR-1207-5P, A PVT1-DERIVED MICRORNA, IS ABUNDANTLY EXPRESSED IN KIDNEY CELLS, AND IS UPREGULATED BY GLUCOSE AND TGF-BETA1. WE ALSO FOUND THAT LIKE PVT1, MIR-1207-5P INCREASES EXPRESSION OF TGF-BETA1, PAI-1, AND FN1 BUT IN A MANNER THAT IS INDEPENDENT OF ITS HOST GENE. IN ADDITION, REGULATION OF MIR-1207-5P EXPRESSION BY GLUCOSE AND TGFBETA1 IS INDEPENDENT OF PVT1. THESE RESULTS PROVIDE EVIDENCE SUPPORTING IMPORTANT ROLES FOR MIR-1207-5P AND ITS HOST GENE IN THE COMPLEX PATHOGENESIS OF DIABETIC NEPHROPATHY. 2013 5 3152 27 GLUCOSE VARIABILITY: HOW DOES IT WORK? A GROWING BODY OF EVIDENCE POINTS TO THE ROLE OF GLUCOSE VARIABILITY (GV) IN THE DEVELOPMENT OF THE MICROVASCULAR AND MACROVASCULAR COMPLICATIONS OF DIABETES. IN THIS REVIEW, WE SUMMARIZE DATA ON GV-INDUCED BIOCHEMICAL, CELLULAR AND MOLECULAR EVENTS INVOLVED IN THE PATHOGENESIS OF DIABETIC COMPLICATIONS. CURRENT DATA INDICATE THAT THE DETERIORATING EFFECT OF GV ON TARGET ORGANS CAN BE REALIZED THROUGH OXIDATIVE STRESS, GLYCATION, CHRONIC LOW-GRADE INFLAMMATION, ENDOTHELIAL DYSFUNCTION, PLATELET ACTIVATION, IMPAIRED ANGIOGENESIS AND RENAL FIBROSIS. THE EFFECTS OF GV ON OXIDATIVE STRESS, INFLAMMATION, ENDOTHELIAL DYSFUNCTION AND HYPERCOAGULABILITY COULD BE AGGRAVATED BY HYPOGLYCEMIA, ASSOCIATED WITH HIGH GV. OSCILLATING HYPERGLYCEMIA CONTRIBUTES TO BETA CELL DYSFUNCTION, WHICH LEADS TO A FURTHER INCREASE IN GV AND COMPLETES THE VICIOUS CIRCLE. IN CELLS, THE GV-INDUCED CYTOTOXIC EFFECT INCLUDES MITOCHONDRIAL DYSFUNCTION, ENDOPLASMIC RETICULUM STRESS AND DISTURBANCES IN AUTOPHAGIC FLUX, WHICH ARE ACCOMPANIED BY REDUCED VIABILITY, ACTIVATION OF APOPTOSIS AND ABNORMALITIES IN CELL PROLIFERATION. THESE EFFECTS ARE REALIZED THROUGH THE UP- AND DOWN-REGULATION OF A LARGE NUMBER OF GENES AND THE ACTIVITY OF SIGNALING PATHWAYS SUCH AS PI3K/AKT, NF-KAPPAB, MAPK (ERK), JNK AND TGF-BETA/SMAD. EPIGENETIC MODIFICATIONS MEDIATE THE POSTPONED EFFECTS OF GLUCOSE FLUCTUATIONS. THE MULTIPLE DETERIORATIVE EFFECTS OF GV PROVIDE FURTHER SUPPORT FOR CONSIDERING IT AS A THERAPEUTIC TARGET IN DIABETES. 2021 6 4210 27 METFORMIN AND VITAMIN D MODULATE INFLAMMATION AND AUTOPHAGY DURING ADIPOSE-DERIVED STEM CELL DIFFERENTIATION. ADIPOSE-DERIVED STEM CELLS (ADSCS) CAME OUT FROM THE REGENERATIVE MEDICINE LANDSCAPE FOR THEIR ABILITY TO DIFFERENTIATE INTO SEVERAL PHENOTYPES, CONTRIBUTING TO TISSUE REGENERATION BOTH IN VITRO AND IN VIVO. DYSREGULATION IN STEM CELL RECRUITMENT AND DIFFERENTIATION DURING ADIPOGENESIS IS LINKED TO A CHRONIC LOW-GRADE INFLAMMATION AND MACROPHAGE INFILTRATION INSIDE THE ADIPOSE TISSUE, INSULIN RESISTANCE, CARDIOVASCULAR DISEASE AND OBESITY. IN THE PRESENT PAPER WE AIMED TO EVALUATE THE ROLE OF METFORMIN AND VITAMIN D, ALONE OR IN COMBINATION, IN MODULATING INFLAMMATION AND AUTOPHAGY IN ADSCS DURING ADIPOGENIC COMMITMENT. ADSCS WERE CULTURED FOR 21 DAYS IN THE PRESENCE OF A SPECIFIC ADIPOGENIC DIFFERENTIATION MEDIUM, TOGETHER WITH METFORMIN, OR VITAMIN D, OR BOTH. WE THEN ANALYZED THE EXPRESSION OF FOXO1 AND HEAT SHOCK PROTEINS (HSP) AND THE SECRETION OF PROINFLAMMATORY CYTOKINES IL-6 AND TNF-ALPHA BY ELISA. AUTOPHAGY WAS ALSO ASSESSED BY SPECIFIC WESTERN BLOT ANALYSIS OF ATG12, LC3B I, AND LC3B II EXPRESSION. OUR RESULTS SHOWED THE ABILITY OF THE CONDITIONED MEDIA TO MODULATE ADIPOGENIC DIFFERENTIATION, FINELY TUNING THE INFLAMMATORY RESPONSE AND AUTOPHAGY. WE OBSERVED A MODULATION IN HSP MRNA LEVELS, AND A SIGNIFICANT DOWNREGULATION IN CYTOKINE SECRETION. TAKEN TOGETHER, OUR FINDINGS SUGGEST THE POSSIBLE APPLICATION OF THESE MOLECULES IN CLINICAL PRACTICE TO COUNTERACT UNCONTROLLED LIPOGENESIS AND PREVENT OBESITY AND OBESITY-RELATED METABOLIC DISORDERS. 2021 7 3243 34 HEPATIC STEATOSIS IN HEPATITIS C IS A STORAGE DISEASE DUE TO HCV INTERACTION WITH MICROSOMAL TRIGLYCERIDE TRANSFER PROTEIN (MTP). LIVER STEATOSIS IS A FREQUENT HISTOLOGICAL FEATURE IN PATIENTS CHRONICALLY INFECTED WITH HEPATITIS C VIRUS (HCV). THE RELATIONSHIP BETWEEN HCV AND HEPATIC STEATOSIS SEEMS TO BE THE RESULT OF BOTH EPIGENETIC AND GENETIC FACTORS. IN VIVO AND IN VITRO STUDIES HAVE SHOWN THAT HCV CAN ALTER INTRAHEPATIC LIPID METABOLISM BY AFFECTING LIPID SYNTHESIS, OXIDATIVE STRESS, LIPID PEROXIDATION, INSULIN RESISTANCE AND THE ASSEMBLY AND SECRETION OF VLDL. MANY STUDIES SUGGEST THAT HCV-RELATED STEATOSIS MIGHT BE THE RESULT OF A DIRECT INTERACTION BETWEEN THE VIRUS AND MTP. IT HAS BEEN DEMONSTRATED THAT MTP IS CRITICAL FOR THE SECRETION OF HCV PARTICLES AND THAT INHIBITION OF ITS LIPID TRANSFER ACTIVITY REDUCES HCV PRODUCTION. HOWEVER, HIGHER DEGREES OF HEPATIC STEATOSIS WERE FOUND IN CHRONIC HEPATITIS C PATIENTS CARRYING THE T ALLELE OF MTP -493G/T POLYMORPHISM THAT SEEMS TO BE ASSOCIATED WITH INCREASED MTP TRANSCRIPTION. WE PROPOSE HERE THAT LIVER STEATOSIS IN HEPATITIS C COULD BE A STORAGE DISEASE INDUCED BY THE EFFECTS OF THE VIRUS AND OF ITS PROTEINS ON THE INTRACELLULAR LIPID MACHINERY AND ON MTP. AVAILABLE DATA SUPPORT THE HYPOTHESIS THAT HCV MAY MODULATE MTP EXPRESSION AND ACTIVITY THROUGH A NUMBER OF MECHANISMS SUCH AS INHIBITION OF ITS ACTIVITY AND TRANSCRIPTIONAL CONTROL. INITIAL UP REGULATION COULD FAVOUR PROPAGATION OF HCV WHILE DOWN REGULATION IN CHRONIC PHASE COULD CAUSE IMPAIRMENT OF TRIGLYCERIDE SECRETION AND EXCESSIVE LIPID ACCUMULATION, WITH ABNORMAL LIPID DROPLETS FACILITATING THE "STORAGE" OF VIRUS PARTICLES FOR PERSISTENT INFECTION. 2010 8 5474 23 RESTORATION OF HISTONE ACETYLATION AMELIORATES DISEASE AND METABOLIC ABNORMALITIES IN A FUS MOUSE MODEL. DYSREGULATION OF EPIGENETIC MECHANISMS IS EMERGING AS A CENTRAL EVENT IN NEURODEGENERATIVE DISORDERS, INCLUDING AMYOTROPHIC LATERAL SCLEROSIS (ALS). IN MANY MODELS OF NEURODEGENERATION, GLOBAL HISTONE ACETYLATION IS DECREASED IN THE AFFECTED NEURONAL TISSUES. HISTONE ACETYLATION IS CONTROLLED BY THE ANTAGONISTIC ACTIONS OF TWO PROTEIN FAMILIES -THE HISTONE ACETYLTRANSFERASES (HATS) AND THE HISTONE DEACETYLASES (HDACS). DRUGS INHIBITING HDAC ACTIVITY ARE ALREADY USED IN THE CLINIC AS ANTI-CANCER AGENTS. THE AIM OF THIS STUDY WAS TO EXPLORE THE THERAPEUTIC POTENTIAL OF HDAC INHIBITION IN THE CONTEXT OF ALS. WE DISCOVERED THAT TRANSGENIC MICE OVEREXPRESSING WILD-TYPE FUS ("TG FUS+/+"), WHICH RECAPITULATE MANY ASPECTS OF HUMAN ALS, SHOWED REDUCED GLOBAL HISTONE ACETYLATION AND ALTERATIONS IN METABOLIC GENE EXPRESSION, RESULTING IN A DYSREGULATED METABOLIC HOMEOSTASIS. CHRONIC TREATMENT OF TG FUS+/+ MICE WITH ACY-738, A POTENT HDAC INHIBITOR THAT CAN CROSS THE BLOOD-BRAIN BARRIER, AMELIORATED THE MOTOR PHENOTYPE AND SUBSTANTIALLY EXTENDED THE LIFE SPAN OF THE TG FUS+/+ MICE. AT THE MOLECULAR LEVEL, ACY-738 RESTORED GLOBAL HISTONE ACETYLATION AND METABOLIC GENE EXPRESSION, THEREBY RE-ESTABLISHING METABOLITE LEVELS IN THE SPINAL CORD. TAKEN TOGETHER, OUR FINDINGS LINK EPIGENETIC ALTERATIONS TO METABOLIC DYSREGULATION IN ALS PATHOLOGY, AND HIGHLIGHT ACY-738 AS A POTENTIAL THERAPEUTIC STRATEGY TO TREAT THIS DEVASTATING DISEASE. 2019 9 2373 31 EPIGENETIC REGULATION OF THE N-TERMINAL TRUNCATED ISOFORM OF MATRIX METALLOPROTEINASE-2 (NTT-MMP-2) AND ITS PRESENCE IN RENAL AND CARDIAC DISEASES. SEVERAL CLINICAL AND EXPERIMENTAL STUDIES HAVE DOCUMENTED A COMPELLING AND CRITICAL ROLE FOR THE FULL-LENGTH MATRIX METALLOPROTEINASE-2 (FL-MMP-2) IN ISCHEMIC RENAL INJURY, PROGRESSIVE RENAL FIBROSIS, AND DIABETIC NEPHROPATHY. A NOVEL N-TERMINAL TRUNCATED ISOFORM OF MMP-2 (NTT-MMP-2) WAS RECENTLY DISCOVERED, WHICH IS INDUCED BY HYPOXIA AND OXIDATIVE STRESS BY THE ACTIVATION OF A LATENT PROMOTER LOCATED IN THE FIRST INTRON OF THE MMP2 GENE. THIS NTT-MMP-2 ISOFORM IS ENZYMATICALLY ACTIVE BUT REMAINS INTRACELLULAR IN OR NEAR THE MITOCHONDRIA. IN THIS PERSPECTIVE ARTICLE, WE FIRST PRESENT THE FINDINGS ABOUT THE DISCOVERY OF THE NTT-MMP-2 ISOFORM, AND ITS FUNCTIONAL AND STRUCTURAL DIFFERENCES AS COMPARED WITH THE FL-MMP-2 ISOFORM. BASED ON PUBLICLY AVAILABLE EPIGENOMICS DATA FROM THE ENCYCLOPEDIA OF DNA ELEMENTS (ENCODE) PROJECT, WE PROVIDE INSIGHTS INTO THE EPIGENETIC REGULATION OF THE LATENT PROMOTER LOCATED IN THE FIRST INTRON OF THE MMP2 GENE, WHICH SUPPORT THE ACTIVATION OF THE NTT-MMP-2 ISOFORM. WE THEN FOCUS ON ITS FUNCTIONAL ASSESSMENT BY COVERING THE ALTERATIONS FOUND IN THE KIDNEY OF TRANSGENIC MICE EXPRESSING THE NTT-MMP-2 ISOFORM. NEXT, WE HIGHLIGHT RECENT FINDINGS REGARDING THE PRESENCE OF THE NTT-MMP-2 ISOFORM IN RENAL DYSFUNCTION, IN KIDNEY AND CARDIAC DISEASES, INCLUDING DAMAGE OBSERVED IN AGING, ACUTE ISCHEMIA-REPERFUSION INJURY (IRI), CHRONIC KIDNEY DISEASE, DIABETIC NEPHROPATHY, AND HUMAN RENAL TRANSPLANTS WITH DELAYED GRAFT FUNCTION. FINALLY, WE BRIEFLY DISCUSS HOW OUR INSIGHTS MAY GUIDE FURTHER EXPERIMENTAL AND CLINICAL STUDIES THAT ARE NEEDED TO ELUCIDATE THE UNDERLYING MECHANISMS AND THE ROLE OF THE NTT-MMP-2 ISOFORM IN RENAL DYSFUNCTION, WHICH MAY HELP TO ESTABLISH IT AS A POTENTIAL THERAPEUTIC TARGET IN KIDNEY DISEASES. 2021 10 595 27 BET PROTEINS REGULATE EXPRESSION OF OSR1 IN EARLY KIDNEY DEVELOPMENT. IN UTERO RENAL DEVELOPMENT IS SUBJECT TO MATERNAL METABOLIC AND ENVIRONMENTAL INFLUENCES AFFECTING LONG-TERM RENAL FUNCTION AND THE RISK OF DEVELOPING CHRONIC KIDNEY FAILURE AND CARDIOVASCULAR DISEASE. EPIGENETIC PROCESSES HAVE BEEN IMPLICATED IN THE ORCHESTRATION OF RENAL DEVELOPMENT AND PRENATAL PROGRAMMING OF NEPHRON NUMBER. HOWEVER, THE ROLE OF MANY EPIGENETIC MODIFIERS FOR KIDNEY DEVELOPMENT IS STILL UNCLEAR. BROMODOMAIN AND EXTRA-TERMINAL DOMAIN (BET) PROTEINS ACT AS HISTONE ACETYLATION READER MOLECULES AND PROMOTE GENE TRANSCRIPTION. BET FAMILY MEMBERS BRD2, BRD3 AND BRD4 ARE EXPRESSED IN THE NEPHROGENIC ZONE DURING KIDNEY DEVELOPMENT. HERE, THE EFFECT OF THE BET INHIBITOR JQ1 ON RENAL DEVELOPMENT IS EVALUATED. INHIBITION OF BET PROTEINS VIA JQ1 LEADS TO REDUCED GROWTH OF METANEPHRIC KIDNEY CULTURES, LOSS OF THE NEPHRON PROGENITOR CELL POPULATION, AND PREMATURE AND DISTURBED NEPHRON DIFFERENTIATION. GENE EXPRESSION OF KEY NEPHRON PROGENITOR TRANSCRIPTION FACTOR OSR1 IS DOWNREGULATED AFTER 24 H BET INHIBITION, WHILE LHX1 AND PAX8 EXPRESSION IS INCREASED. MINING OF BRD4 CHIP-SEQ AND GENE EXPRESSION DATA IDENTIFY OSR1 AS A KEY FACTOR REGULATED BY BRD4-CONTROLLED GENE ACTIVATION. INHIBITION OF BRD4 BY BET INHIBITOR JQ1 LEADS TO DOWNREGULATION OF OSR1, THEREBY CAUSING A DISTURBANCE IN THE BALANCE OF NEPHRON PROGENITOR CELL SELF-RENEWAL AND PREMATURE DIFFERENTIATION OF THE NEPHRON, WHICH ULTIMATELY LEADS TO KIDNEY HYPOPLASIA AND DISTURBED NEPHRON DEVELOPMENT. THIS RAISES QUESTIONS ABOUT THE POTENTIAL TERATOGENIC EFFECTS OF BET INHIBITORS FOR EMBRYONIC DEVELOPMENT. IN SUMMARY, OUR WORK HIGHLIGHTS THE ROLE OF BET PROTEINS FOR PRENATAL PROGRAMMING OF NEPHROGENESIS AND IDENTIFIES OSR1 AS A POTENTIAL TARGET OF BET PROTEINS. 2021 11 2002 22 EPIGENETIC AND POST-TRANSCRIPTIONAL REPRESSION SUPPORT METABOLIC SUPPRESSION IN CHRONICALLY HYPOXIC GOLDFISH. GOLDFISH ENTER A HYPOMETABOLIC STATE TO SURVIVE CHRONIC HYPOXIA. WE RECENTLY DESCRIBED TISSUE-SPECIFIC CONTRIBUTIONS OF MEMBRANE LIPID COMPOSITION REMODELING AND MITOCHONDRIAL FUNCTION TO METABOLIC SUPPRESSION ACROSS DIFFERENT GOLDFISH TISSUES. HOWEVER, THE MOLECULAR AND ESPECIALLY EPIGENETIC FOUNDATIONS OF HYPOXIA TOLERANCE IN GOLDFISH UNDER METABOLIC SUPPRESSION ARE NOT WELL UNDERSTOOD. HERE WE SHOW THAT COMPONENTS OF THE MOLECULAR OXYGEN-SENSING MACHINERY ARE ROBUSTLY ACTIVATED ACROSS TISSUES IRRESPECTIVE OF HYPOXIA DURATION. INDUCTION OF GENE EXPRESSION OF ENZYMES INVOLVED IN DNA METHYLATION TURNOVER AND MICRORNA BIOGENESIS SUGGEST A ROLE FOR EPIGENETIC TRANSCRIPTIONAL AND POST-TRANSCRIPTIONAL SUPPRESSION OF GENE EXPRESSION IN THE HYPOXIA-ACCLIMATED BRAIN. CONVERSELY, MECHANISTIC TARGET OF RAPAMYCIN-DEPENDENT TRANSLATIONAL MACHINERY ACTIVITY IS NOT REDUCED IN LIVER AND WHITE MUSCLE, SUGGESTING THIS PATHWAY DOES NOT CONTRIBUTE TO LOWERING CELLULAR ENERGY EXPENDITURE. FINALLY, MOLECULAR EVIDENCE SUPPORTS PREVIOUSLY REPORTED CHRONIC HYPOXIA-DEPENDENT CHANGES IN MEMBRANE CHOLESTEROL, LIPID METABOLISM AND MITOCHONDRIAL FUNCTION VIA CHANGES IN TRANSCRIPTS INVOLVED IN CHOLESTEROL BIOSYNTHESIS, BETA-OXIDATION, AND MITOCHONDRIAL FUSION IN MULTIPLE TISSUES. OVERALL, THIS STUDY SHOWS THAT CHRONIC HYPOXIA ROBUSTLY INDUCES EXPRESSION OF OXYGEN-SENSING MACHINERY ACROSS TISSUES, INDUCES REPRESSIVE TRANSCRIPTIONAL AND POST-TRANSCRIPTIONAL EPIGENETIC MARKS ESPECIALLY IN THE CHRONIC HYPOXIA-ACCLIMATED BRAIN AND SUPPORTS A ROLE FOR MEMBRANE REMODELING AND MITOCHONDRIAL FUNCTION AND DYNAMICS IN PROMOTING METABOLIC SUPPRESSION. 2022 12 1824 26 EFFECTS OF ENVIRONMENTAL CONDITIONS ON NEPHRON NUMBER: MODELING MATERNAL DISEASE AND EPIGENETIC REGULATION IN RENAL DEVELOPMENT. A GROWING BODY OF EVIDENCE SUGGESTS THAT LOW NEPHRON NUMBERS AT BIRTH CAN INCREASE THE RISK OF CHRONIC KIDNEY DISEASE OR HYPERTENSION LATER IN LIFE. ENVIRONMENTAL STRESSORS, SUCH AS MATERNAL MALNUTRITION, MEDICATION AND SMOKING, CAN INFLUENCE RENAL SIZE AT BIRTH. USING METANEPHRIC ORGAN CULTURES TO MODEL SINGLE-VARIABLE ENVIRONMENTAL CONDITIONS, MODELS OF MATERNAL DISEASE WERE EVALUATED FOR PATTERNS OF DEVELOPMENTAL IMPAIRMENT. WHILE HYPERTHERMIA HAD LIMITED EFFECTS ON RENAL DEVELOPMENT, FETAL IRON DEFICIENCY WAS ASSOCIATED WITH SEVERE IMPAIRMENT OF RENAL GROWTH AND NEPHROGENESIS WITH AN ALL-PROXIMAL PHENOTYPE. CULTURING KIDNEY EXPLANTS UNDER HIGH GLUCOSE CONDITIONS LED TO CELLULAR AND TRANSCRIPTOMIC CHANGES RESEMBLING HUMAN DIABETIC NEPHROPATHY. SHORT-TERM HIGH GLUCOSE CULTURE CONDITIONS WERE SUFFICIENT FOR LONG-TERM ALTERATIONS IN DNA METHYLATION-ASSOCIATED EPIGENETIC MEMORY. FINALLY, THE ROLE OF EPIGENETIC MODIFIERS IN RENAL DEVELOPMENT WAS TESTED USING A SMALL COMPOUND LIBRARY. AMONG THE SELECTED EPIGENETIC INHIBITORS, VARIOUS COMPOUNDS ELICITED AN EFFECT ON RENAL GROWTH, SUCH AS HDAC (ENTINOSTAT, TH39), HISTONE DEMETHYLASE (DEFERASIROX, DEFEROXAMINE) AND HISTONE METHYLTRANSFERASE (CYPROHEPTADINE) INHIBITORS. THUS, METANEPHRIC ORGAN CULTURES PROVIDE A VALUABLE SYSTEM FOR STUDYING METABOLIC CONDITIONS AND A TOOL FOR SCREENING FOR EPIGENETIC MODIFIERS IN RENAL DEVELOPMENT. 2021 13 19 24 5-AZACYTYDINE AND RESVERATROL REVERSE SENESCENCE AND AGEING OF ADIPOSE STEM CELLS VIA MODULATION OF MITOCHONDRIAL DYNAMICS AND AUTOPHAGY. OBESITY AND ENDOCRINE DISORDERS HAVE BECOME PREVALENT ISSUES IN THE FIELD OF BOTH HUMAN AND VETERINARY MEDICINE. EQUINE METABOLIC SYNDROME IS A COMPLEX DISORDER INVOLVING ALTERNATION IN METABOLISM AND CHRONIC SYSTEMIC INFLAMMATION. IT HAS BEEN SHOWN THAT UNFAVOURABLE MICROENVIRONMENT OF INFLAMED ADIPOSE TISSUE NEGATIVELY AFFECTS ADIPOSE STEM CELL POPULATION (ASC) RESIDING WITHIN, MARKEDLY LIMITING THEIR THERAPEUTIC POTENTIAL. ASCS(EMS) ARE CHARACTERIZED BY INCREASED SENESCENCE APOPTOSIS, EXCESSIVE ACCUMULATION OF REACTIVE OXYGEN SPECIES (ROS), MITOCHONDRIA DETERIORATION AND "AUTOPHAGIC FLUX." THE AIM OF THE PRESENT STUDY WAS TO EVALUATE WHETHER TREATMENT OF ASCS(EMS) WITH A COMBINATION OF 5-AZACYTYDINE (AZA) AND RESVERATROL (RES) WOULD REVERSE AGED PHENOTYPE OF THESE CELLS. FOR THIS REASON, WE PERFORMED THE FOLLOWING ANALYZES: MOLECULAR BIOLOGY (RT-PCR), MICROSCOPIC (IMMUNOFLUORESCENCE, TEM) AND FLOW CYTOMETRY (JC-1, ROS, KI67). WE EVALUATED THE MITOCHONDRIAL STATUS, DYNAMICS AND CLEARANCE AS WELL AS AUTOPHAGIC PATHWAYS. FURTHERMORE, WE INVESTIGATED EPIGENETIC ALTERNATIONS IN TREATED CELLS BY MEASURING THE EXPRESSION OF TET GENES AND ANALYSIS OF DNA METHYLATION STATUS. WE HAVE DEMONSTRATED THAT AZA/RES TREATMENT OF ASCS(EMS) IS ABLE TO REJUVENATE THESE CELLS BY MODULATING MITOCHONDRIAL DYNAMICS, IN PARTICULAR BY PROMOTING MITOCHONDRIAL FUSION OVER FISSION. AFTER AZA/RES TREATMENT, ASCS(EMS) WERE CHARACTERIZED BY INCREASED PROLIFERATION RATE, DECREASED APOPTOSIS AND SENESCENCE AND LOWER ROS ACCUMULATION. OUR FINDINGS OFFER A NOVEL APPROACH AND POTENTIAL TARGETS FOR THE BENEFICIAL EFFECTS OF AZA/RES IN AMELIORATING STEM CELL DYSFUNCTIONS. 2019 14 2791 27 FAT-FREE P300 IS GOOD FOR SCAR-FREE TISSUE REPAIR. FIBROSIS, THE DEADLY PATHOLOGICAL MANIFESTATION OF AN ABNORMAL TISSUE REMODELING IN ANY ORGAN DUE TO EXCESSIVE COLLAGEN DEPOSITION, IS ASSOCIATED WITH A WIDE VARIETY OF ORGAN FAILURE-RELATED HUMAN DISEASES. CHRONIC STRESS OR REPEATED INJURY IN A PARTICULAR ORGAN INDUCES ABNORMAL MOLECULAR SIGNALS THAT LEAD TO SUPER-ACTIVATION OF MATRIX PROTEIN PRODUCING FIBROBLASTS, EXCESSIVE MATRIX PROTEINS ACCUMULATION, LOSS OF PHYSIOLOGICAL TISSUE ARCHITECTURE OR ELASTICITY, AND ULTIMATELY LEADING TO ORGAN FAILURE. THERE IS NO EFFECTIVE THERAPY FOR FIBROSIS. FACTOR ACETYLTRANSFERASE P300 (FATP300), A MAJOR EPIGENETIC REGULATOR THAT ACETYLATES SPECIFIC LYSINES IN HISTONES AND TRANSCRIPTION FACTORS, IS ESSENTIAL FOR ELEVATED COLLAGEN SYNTHESIS AND THE LEVELS OF FATP300 ARE SIGNIFICANTLY ELEVATED IN DIFFERENT FIBROTIC TISSUES. PHARMACOLOGICAL INHIBITION OF FAT ACTIVITY OF P300 IS ASSOCIATED WITH DECREASED COLLAGEN SYNTHESIS BY FIBROBLASTS IN TISSUES AND AMELIORATION OF ORGAN FIBROSIS. THEREFORE, FAT-FREE P300 IS SUPERIOR FOR PHYSIOLOGICAL TISSUE REPAIR AND MUST BE EXPLOITED AS A VIABLE THERAPEUTIC TARGET AGAINST MULTI-ORGAN FIBROSIS. 2014 15 3327 36 HISTONE DEACETYLASE 4 PROMOTES CHOLESTATIC LIVER INJURY IN THE ABSENCE OF PROHIBITIN-1. PROHIBITIN-1 (PHB1) IS AN EVOLUTIONARILY CONSERVED PLEIOTROPIC PROTEIN THAT PARTICIPATES IN DIVERSE PROCESSES DEPENDING ON ITS SUBCELLULAR LOCALIZATION AND INTERACTOME. RECENT DATA HAVE INDICATED A DIVERSE ROLE FOR PHB1 IN THE PATHOGENESIS OF OBESITY, CANCER, AND INFLAMMATORY BOWEL DISEASE, AMONG OTHERS. DATA PRESENTED HERE SUGGEST THAT PHB1 IS ALSO LINKED TO CHOLESTATIC LIVER DISEASE. EXPRESSION OF PHB1 IS MARKEDLY REDUCED IN PATIENTS WITH PRIMARY BILIARY CIRRHOSIS AND BILIARY ATRESIA OR WITH ALAGILLE SYNDROME, TWO MAJOR PEDIATRIC CHOLESTATIC CONDITIONS. IN THE EXPERIMENTAL MODEL OF BILE DUCT LIGATION, SILENCING OF PHB1 INDUCED LIVER FIBROSIS, REDUCED ANIMAL SURVIVAL, AND INDUCED BILE DUCT PROLIFERATION. IMPORTANTLY, THE MODULATORY EFFECT OF PHB1 IS NOT DEPENDENT ON ITS KNOWN MITOCHONDRIAL FUNCTION. ALSO, PHB1 INTERACTS WITH HISTONE DEACETYLASE 4 (HDAC4) IN THE PRESENCE OF BILE ACIDS. HENCE, PHB1 DEPLETION LEADS TO INCREASED NUCLEAR HDAC4 CONTENT AND ITS ASSOCIATED EPIGENETIC CHANGES. REMARKABLY, HDAC4 SILENCING AND THE ADMINISTRATION OF THE HDAC INHIBITOR PARTHENOLIDE DURING OBSTRUCTIVE CHOLESTASIS IN VIVO PROMOTE GENOMIC REPROGRAMMING, LEADING TO REGRESSION OF THE FIBROTIC PHENOTYPE IN LIVER-SPECIFIC PHB1 KNOCKOUT MICE. CONCLUSION: PHB1 IS AN IMPORTANT MEDIATOR OF CHOLESTATIC LIVER INJURY THAT REGULATES THE ACTIVITY OF HDAC4, WHICH CONTROLS SPECIFIC EPIGENETIC MARKERS; THESE RESULTS IDENTIFY POTENTIAL NOVEL STRATEGIES TO TREAT LIVER INJURY AND FIBROSIS, PARTICULARLY AS A CONSEQUENCE OF CHRONIC CHOLESTASIS. 2015 16 26 28 A 6-ALKYLSALICYLATE HISTONE ACETYLTRANSFERASE INHIBITOR INHIBITS HISTONE ACETYLATION AND PRO-INFLAMMATORY GENE EXPRESSION IN MURINE PRECISION-CUT LUNG SLICES. LYSINE ACETYLATIONS ARE POST-TRANSLATIONAL MODIFICATIONS OF CELLULAR PROTEINS, THAT ARE CRUCIAL IN THE REGULATION OF MANY CELLULAR PROCESSES. LYSINE ACETYLATIONS ON HISTONE PROTEINS ARE PART OF THE EPIGENETIC CODE REGULATING GENE EXPRESSION AND ARE INSTALLED BY HISTONE ACETYLTRANSFERASES. OBSERVATIONS THAT INFLAMMATORY LUNG DISEASES, SUCH AS ASTHMA AND CHRONIC OBSTRUCTIVE PULMONARY DISEASE, ARE CHARACTERIZED BY INCREASED HISTONE ACETYLTRANSFERASE ACTIVITY INDICATE THAT DEVELOPMENT OF SMALL MOLECULE INHIBITORS FOR THESE ENZYMES MIGHT BE A VALUABLE APPROACH TOWARDS NEW THERAPIES FOR THESE DISEASES. THE 6-ALKYLSALICYLATE MG149 IS A CANDIDATE TO EXPLORE THIS HYPOTHESIS BECAUSE IT HAS BEEN DEMONSTRATED TO INHIBIT THE MYST TYPE HISTONE ACETYLTRANSFERASES. IN THIS STUDY, WE DETERMINED THE K(I) VALUE FOR INHIBITION OF THE MYST TYPE HISTONE ACETYLTRANSFERASE KAT8 BY MG149 TO BE 39 +/- 7.7 MUM. UPON INVESTIGATING WHETHER THE INHIBITION OF HISTONE ACETYLTRANSFERASES BY MG149 CORRELATES WITH INHIBITION OF HISTONE ACETYLATION IN MURINE PRECISION-CUT LUNG SLICES, INHIBITION OF ACETYLATION WAS OBSERVED USING AN LC-MS/MS BASED ASSAY ON HISTONE H4 RES 4-17, WHICH CONTAINS THE TARGET LYSINE OF KAT8. FOLLOWING UP ON THIS, UPON TREATMENT WITH MG149, REDUCED PRO-INFLAMMATORY GENE EXPRESSION WAS OBSERVED IN LIPOPOLYSACCHARIDE AND INTERFERON GAMMA STIMULATED MURINE PRECISION-CUT LUNG SLICES. BASED ON THIS, WE PROPOSE THAT 6-ALKYLSALICYLATES SUCH AS MG149 HAVE POTENTIAL FOR DEVELOPMENT TOWARDS APPLICATIONS IN THE TREATMENT OF INFLAMMATORY LUNG DISEASES. 2017 17 1902 24 ENHANCED EXPRESSION OF THE NUCLEAR ENVELOPE LAP2 TRANSCRIPTIONAL REPRESSORS IN NORMAL AND MALIGNANT ACTIVATED LYMPHOCYTES. EXTENSIVE RESEARCH IN RECENT YEARS HAS BROADENED THE FUNCTIONS OF NUCLEAR ENVELOPE PROTEINS BEYOND SIMPLY STABILIZING THE NUCLEUS ARCHITECTURE. PARTICULARLY, INTEGRAL NUCLEAR MEMBRANE PROTEINS, SUCH AS THE ALTERNATIVE SPLICED ISOFORMS OF LAMINA-ASSOCIATED POLYPEPTIDE 2 (LAP2), HAVE BEEN SHOWN TO BE IMPORTANT FOR THE INITIATION OF REPLICATION AND REPRESSION OF TRANSCRIPTION. THE LATTER IS REGULATED BY EPIGENETIC CHANGES, INDUCED BY THE BINDING OF LAP2BETA TO HISTONE DEACETYLASE-3 (HDAC3), RESULTING IN HISTONE H4 DEACETYLATION. INVOLVEMENT OF NUCLEAR ENVELOPE PROTEINS IN PATHOLOGICAL PROLIFERATIVE CONDITIONS, MAINLY THOSE INVOLVING ABNORMAL RECRUITMENT AND ACTIVATION OF HDACS, IS STILL UNKNOWN. IN THIS PAPER, WE SHOW THAT VARIOUS NUCLEAR ENVELOPE PROTEINS ARE HIGHLY EXPRESSED IN NORMAL AND MALIGNANT ACTIVATED LYMPHOCYTES. SPECIFICALLY, RAPIDLY REPLICATING CELLS OF VARIOUS HEMATOLOGICAL MALIGNANCIES HIGHLY EXPRESS LAP2BETA, WHILE SLOWLY PROLIFERATING MALIGNANT CELLS OF CHRONIC MALIGNANT HEMATOLOGICAL DISEASES DO NOT. TAKING TOGETHER THE ELEVATED EXPRESSION OF LAP2BETA IN HIGHLY PROLIFERATIVE MALIGNANT CELLS WITH ITS KNOWN ABILITY TO MODIFY HISTONES THROUGH BINDING WITH HDAC3 RAISES THE POSSIBILITY OF ITS ROLE IN HEMATOLOGICAL MALIGNANCIES INVOLVING ABERRANT ACTIVITY OF HDAC3. BASED ON OUR PRESENTED RESULTS, WE BELIEVE THAT THE LAP2-HDAC REGULATORY PATHWAY SHOULD BE STUDIED AS A NEW TARGET FOR RATIONAL THERAPY. 2007 18 85 27 A NOVEL INDOLE COMPOUND MA-35 ATTENUATES RENAL FIBROSIS BY INHIBITING BOTH TNF-ALPHA AND TGF-BETA(1) PATHWAYS. RENAL FIBROSIS IS CLOSELY RELATED TO CHRONIC INFLAMMATION AND IS UNDER THE CONTROL OF EPIGENETIC REGULATIONS. BECAUSE THE SIGNALING OF TRANSFORMING GROWTH FACTOR-BETA(1) (TGF-BETA(1)) AND TUMOR NECROSIS FACTOR-ALPHA (TNF-ALPHA) PLAY KEY ROLES IN PROGRESSION OF RENAL FIBROSIS, DUAL BLOCKADE OF TGF-BETA(1) AND TNF-ALPHA IS DESIRED AS ITS THERAPEUTIC APPROACH. HERE WE SCREENED SMALL MOLECULES SHOWING ANTI-TNF-ALPHA ACTIVITY IN THE COMPOUND LIBRARY OF INDOLE DERIVATIVES. 11 OUT OF 41 INDOLE DERIVATIVES INHIBITED THE TNF-ALPHA EFFECT. AMONG THEM, MITOCHONIC ACID 35 (MA-35), 5-(3, 5-DIMETHOXYBENZYLOXY)-3-INDOLEACETIC ACID, SHOWED THE POTENT EFFECT. THE ANTI-TNF-ALPHA ACTIVITY WAS MEDIATED BY INHIBITING IKAPPAB KINASE PHOSPHORYLATION, WHICH ATTENUATED THE LPS/GAIN-INDUCED HEPATIC INFLAMMATION IN THE MICE. ADDITIONALLY, MA-35 CONCURRENTLY SHOWED AN ANTI-TGF-BETA(1) EFFECT BY INHIBITING SMAD3 PHOSPHORYLATION, RESULTING IN THE DOWNREGULATION OF TGF-BETA(1)-INDUCED FIBROTIC GENE EXPRESSION. IN UNILATERAL URETER OBSTRUCTED MOUSE KIDNEY, WHICH IS A RENAL FIBROSIS MODEL, MA-35 ATTENUATED RENAL INFLAMMATION AND FIBROSIS WITH THE DOWNREGULATION OF INFLAMMATORY CYTOKINES AND FIBROTIC GENE EXPRESSIONS. FURTHERMORE, MA-35 INHIBITED TGF-BETA(1)-INDUCED H3K4ME1 HISTONE MODIFICATION OF THE FIBROTIC GENE PROMOTER, LEADING TO A DECREASE IN THE FIBROTIC GENE EXPRESSION. MA-35 AFFECTS MULTIPLE SIGNALING PATHWAYS INVOLVED IN THE FIBROSIS AND MAY RECOVER EPIGENETIC MODIFICATION; THEREFORE, IT COULD POSSIBLY BE A NOVEL THERAPEUTIC DRUG FOR FIBROSIS. 2017 19 4861 24 ORGANIC ANION TRANSPORTER 1 IS AN HDAC4-REGULATED MEDIATOR OF NOCICEPTIVE HYPERSENSITIVITY IN MICE. PERSISTENT PAIN IS SUSTAINED BY MALADAPTIVE CHANGES IN GENE TRANSCRIPTION RESULTING IN ALTERED FUNCTION OF THE RELEVANT CIRCUITS; THERAPIES ARE STILL UNSATISFACTORY. THE EPIGENETIC MECHANISMS AND AFFECTED GENES LINKING NOCICEPTIVE ACTIVITY TO TRANSCRIPTIONAL CHANGES AND PATHOLOGICAL SENSITIVITY ARE UNCLEAR. HERE, WE FOUND THAT, AMONG SEVERAL HISTONE DEACETYLASES (HDACS), SYNAPTIC ACTIVITY SPECIFICALLY AFFECTS HDAC4 IN MURINE SPINAL CORD DORSAL HORN NEURONS. NOXIOUS STIMULI THAT INDUCE LONG-LASTING INFLAMMATORY HYPERSENSITIVITY CAUSE NUCLEAR EXPORT AND INACTIVATION OF HDAC4. THE DEVELOPMENT OF INFLAMMATION-ASSOCIATED MECHANICAL HYPERSENSITIVITY, BUT NEITHER ACUTE NOR BASAL SENSITIVITY, IS IMPAIRED BY THE EXPRESSION OF A CONSTITUTIVELY NUCLEAR LOCALIZED HDAC4 MUTANT. NEXT GENERATION RNA-SEQUENCING REVEALED AN HDAC4-REGULATED GENE PROGRAM COMPRISING MEDIATORS OF SENSITIZATION INCLUDING THE ORGANIC ANION TRANSPORTER OAT1, KNOWN FOR ITS RENAL TRANSPORT FUNCTION. USING PHARMACOLOGICAL AND MOLECULAR TOOLS TO MODULATE OAT1 ACTIVITY OR EXPRESSION, WE CAUSALLY LINK OAT1 TO PERSISTENT INFLAMMATORY HYPERSENSITIVITY IN MICE. THUS, HDAC4 IS A KEY EPIGENETIC REGULATOR THAT TRANSLATES NOCICEPTIVE ACTIVITY INTO SENSITIZATION BY REGULATING OAT1, WHICH IS A POTENTIAL TARGET FOR PAIN-RELIEVING THERAPIES. 2022 20 4507 24 MRTF: BASIC BIOLOGY AND ROLE IN KIDNEY DISEASE. A LESSER KNOWN BUT CRUCIALLY IMPORTANT DOWNSTREAM EFFECT OF RHO FAMILY GTPASES IS THE REGULATION OF GENE EXPRESSION. THIS MAJOR ROLE IS MEDIATED VIA THE CYTOSKELETON, THE ORGANIZATION OF WHICH DICTATES THE NUCLEOCYTOPLASMIC SHUTTLING OF A SET OF TRANSCRIPTION FACTORS. CENTRAL AMONG THESE IS MYOCARDIN-RELATED TRANSCRIPTION FACTOR (MRTF), WHICH UPON ACTIN POLYMERIZATION TRANSLOCATES TO THE NUCLEUS AND BINDS TO ITS COGNATE PARTNER, SERUM RESPONSE FACTOR (SRF). THE MRTF/SRF COMPLEX THEN DRIVES A LARGE COHORT OF GENES INVOLVED IN CYTOSKELETON REMODELING, CONTRACTILITY, EXTRACELLULAR MATRIX ORGANIZATION AND MANY OTHER PROCESSES. ACCORDINGLY, MRTF, ACTIVATED BY A VARIETY OF MECHANICAL AND CHEMICAL STIMULI, AFFECTS A PLETHORA OF FUNCTIONS WITH PHYSIOLOGICAL AND PATHOLOGICAL RELEVANCE. THESE INCLUDE CELL MOTILITY, DEVELOPMENT, METABOLISM AND THUS METASTASIS FORMATION, INFLAMMATORY RESPONSES AND-PREDOMINANTLY-ORGAN FIBROSIS. THE AIM OF THIS REVIEW IS TWOFOLD: TO PROVIDE AN UP-TO-DATE SUMMARY ABOUT THE BASIC BIOLOGY AND REGULATION OF THIS VERSATILE TRANSCRIPTIONAL COACTIVATOR; AND TO HIGHLIGHT ITS PRINCIPAL INVOLVEMENT IN THE PATHOBIOLOGY OF KIDNEY DISEASE. ACTING THROUGH BOTH DIRECT TRANSCRIPTIONAL AND EPIGENETIC MECHANISMS, MRTF PLAYS A KEY (YET NOT FULLY APPRECIATED) ROLE IN THE INDUCTION OF A PROFIBROTIC EPITHELIAL PHENOTYPE (PEP) AS WELL AS IN FIBROBLAST-MYOFIBROBLAST TRANSITION, PRIME PATHOMECHANISMS IN CHRONIC KIDNEY DISEASE AND RENAL FIBROSIS. 2021