1 3807 149 INTRACELLULAR PROTONS ACCELERATE AGING AND SWITCH ON AGING HALLMARKS IN MICE. DIET-INDUCED METABOLIC ACIDOSIS IS ASSOCIATED WITH THE IMPAIRMENT OF BONE METABOLISM AND AN INCREASED RISK OF A NUMBER OF CHRONIC NONCOMMUNICABLE DISEASES, SUCH AS TYPE 2 DIABETES MELLITUS AND HYPERTENSION. THE SERUM BICARBONATE LEVEL IS AN INDEPENDENT PREDICTOR OF CHRONIC KIDNEY DISEASE PROGRESSION. WE INVESTIGATED WHETHER PROTON ACCELERATES AGING BY ANALYZING BOTH COUPLING FACTOR 6-OVEREXPRESSING TRANSGENIC (TG) AND HIGH SALT-FED MICE WHICH DISPLAY SUSTAINED INTRACELLULAR ACIDOSIS, DUE TO ENHANCED PROTON IMPORT THROUGH ECTO-F(1) F(O) COMPLEX AND/OR REDUCED PROTON EXPORT THROUGH NA(+) -K(+) ATPASE INHIBITION. BOTH TYPES OF MICE DISPLAYED SHORTENED LIFESPAN AND EARLY SENESCENCE-ASSOCIATED PHENOTYPES SUCH AS SIGNS OF HAIR GREYING AND ALOPECIA, WEIGHT LOSS, AND/OR REDUCED ORGAN MASS. IN CHRONIC INTRACELLULAR ACIDOSIS MICE, AUTOPHAGY WAS IMPAIRED BY REGRESSION OF ATG7, AN INCREASE IN NUCLEAR ACETYLATED LC3 II, AND ACETYLATION OF ATG7. THE INCREASE IN HISTONE 3 TRIMETHYLATION AT LYSINE 4 (H3K4ME3) AND H4K20ME3 AND THE DECREASE IN H3K9ME3 AND H3K27ME3 WERE OBSERVED IN THE HEART AND KIDNEY OBTAINED FROM BOTH TG AND HIGH SALT-FED MICE. THE DECREASE IN LAMIN A/C, EMERIN, AND HETEROCHROMATIN PROTEIN 1ALPHA WITHOUT CHANGES IN BARRIER-TO-AUTOINTEGRATION FACTOR AND HIGH-MOBILITY GROUP BOX 1 WAS CONFIRMED IN TG AND HIGH SALT-FED MICE. SUPPRESSION OF NUCLEAR HISTONE DEACETYLASE 3-EMERIN SYSTEM IS ATTRIBUTABLE TO EPIGENETIC REGRESSION OF ATG7 AND H4K5 ACETYLATION. THESE FINDINGS WILL SHED LIGHT ON NOVEL AGING AND IMPAIRED AUTOPHAGY MECHANISM, AND PROVIDE IMPLICATIONS IN A TARGET FOR ANTIAGING THERAPY. 2018 2 4731 103 NOVEL ANTI-AGING GENE NM_026333 CONTRIBUTES TO PROTON-INDUCED AGING VIA NCX1-PATHWAY. DIET-INDUCED METABOLIC ACIDOSIS IS ASSOCIATED WITH THE IMPAIRMENT OF BONE METABOLISM AND AN INCREASED RISK OF A NUMBER OF CHRONIC NONCOMMUNICABLE DISEASES, SUCH AS TYPE 2 DIABETES MELLITUS AND HYPERTENSION. LOW SERUM BICARBONATE IS ASSOCIATED WITH HIGH MORTALITY IN HEALTHY OLDER INDIVIDUALS. RECENTLY, WE DEMONSTRATED THAT BOTH COUPLING FACTOR 6 (CF6)-OVEREXPRESSING TRANSGENIC (TG) AND HIGH SALT-FED MICE WHICH HAD SUSTAINED INTRACELLULAR ACIDOSIS, DUE TO ENHANCED PROTON IMPORT THROUGH ECTO-F(1)F(O) COMPLEX AND/OR REDUCED PROTON EXPORT THROUGH NA(+)-K(+) ATPASE INHIBITION, DISPLAYED SHORTENED LIFESPAN AND EARLY SENESCENCE-ASSOCIATED PHENOTYPES SUCH AS SIGNS OF HAIR GREYING AND ALOPECIA, WEIGHT LOSS, AND/OR REDUCED ORGAN MASS. IN THIS STUDY, WE SEARCHED CAUSATIVE GENES OF PROTON-INDUCED AGING IN CF6-OVEREXPRESSING TG AND HIGH SALT-FED MICE. WE DISCOVERED NM_026333 AS A NOVEL ANTI-AGING GENE WHICH WAS DOWNREGULATED IN THE HEART AND KIDNEY IN BOTH TYPES OF MICE. NM_026333 PROTEIN CONSISTS OF 269 AMINO ACIDS WITH TRANSMEMBRANE REGION (90-193AA). INDUCTION OF NM_026333 OR RECOMBINANT PROTEIN RESCUED TG CELLS AND CF6-TREATED HUMAN CELLS FROM AGING HALLMARKS OF IMPAIRED AUTOPHAGY, GENOMIC INSTABILITY, AND EPIGENETIC ALTERATION. NM_026333 PROTEIN DIRECTLY BOUND PLASMA MEMBRANE NA(+)-CA(2+) EXCHANGER 1 (NCX1) TO SUPPRESS ITS REVERSE MODE, AND CANCELLED PROTON-INDUCED EPIGENETIC REGRESSION OF ATG7 THAT WAS CAUSED BY H3K4 AND H4K20 TRI-METHYLATION VIA SUPPRESSION OF DEMETHYLASE AND H4K5 ACETYLATION VIA SUPPRESSION OF NUCLEAR HDAC3-HDAC4-EMERIN SYSTEM. NM_026333 ALSO ATTENUATED PROTON-INDUCED IMPAIRED FORMATION OF AUTOLYSOSOME, AN INCREASE IN NUCLEAR ACETYLATED LC3 II, AND ACETYLATION OF ATG7. THESE EFFECTS REAPPEARED BY NCX1 INHIBITOR. FURTHERMORE, NCX1 INHIBITOR EXTENDED LIFESPAN COMPARED WITH VEHICLE-TREATMENT IN TG MICE. THIS STUDY WILL SHED LIGHT ON NOVEL AGING MECHANISM AND PROVIDE IMPLICATIONS IN A TARGET FOR ANTI-AGING THERAPY. 2018 3 3894 21 LAMIN B1 REGULATES SOMATIC MUTATIONS AND PROGRESSION OF B-CELL MALIGNANCIES. SOMATIC HYPERMUTATION (SHM) IS A PIVOTAL PROCESS IN ADAPTIVE IMMUNITY THAT OCCURS IN THE GERMINAL CENTRE AND ALLOWS B CELLS TO CHANGE THEIR PRIMARY DNA SEQUENCE AND DIVERSIFY THEIR ANTIGEN RECEPTORS. HERE, WE REPORT THAT GENOME BINDING OF LAMIN B1, A COMPONENT OF THE NUCLEAR ENVELOPE INVOLVED IN EPIGENETIC CHROMATIN REGULATION, IS REDUCED DURING B-CELL ACTIVATION AND FORMATION OF LYMPHOID GERMINAL CENTRES. CHROMATIN IMMUNOPRECIPITATION-SEQ ANALYSIS SHOWED THAT KAPPA AND HEAVY VARIABLE IMMUNOGLOBULIN DOMAINS WERE RELEASED FROM THE LAMIN B1 SUPPRESSIVE ENVIRONMENT WHEN SHM WAS INDUCED IN B CELLS. RNA INTERFERENCE-MEDIATED REDUCTION OF LAMIN B1 RESULTED IN SPONTANEOUS SHM AS WELL AS KAPPA-LIGHT CHAIN ABERRANT SURFACE EXPRESSION. FINALLY, LAMIN B1 EXPRESSION LEVEL CORRELATED WITH PROGRESSION-FREE AND OVERALL SURVIVAL IN CHRONIC LYMPHOCYTIC LEUKAEMIA, AND WAS STRONGLY INVOLVED IN THE TRANSFORMATION OF FOLLICULAR LYMPHOMA. IN SUMMARY, HERE WE REPORT THAT LAMIN B1 IS A NEGATIVE EPIGENETIC REGULATOR OF SHM IN NORMAL B-CELLS AND A 'MUTATIONAL GATEKEEPER', SUPPRESSING THE ABERRANT MUTATIONS THAT DRIVE LYMPHOID MALIGNANCY. 2018 4 5449 26 REPRESSION OF THE ANTIOXIDANT NRF2 PATHWAY IN PREMATURE AGING. HUTCHINSON-GILFORD PROGERIA SYNDROME (HGPS) IS A RARE, INVARIABLY FATAL PREMATURE AGING DISORDER. THE DISEASE IS CAUSED BY CONSTITUTIVE PRODUCTION OF PROGERIN, A MUTANT FORM OF THE NUCLEAR ARCHITECTURAL PROTEIN LAMIN A, LEADING, THROUGH UNKNOWN MECHANISMS, TO DIVERSE MORPHOLOGICAL, EPIGENETIC, AND GENOMIC DAMAGE AND TO MESENCHYMAL STEM CELL (MSC) ATTRITION IN VIVO. USING A HIGH-THROUGHPUT SIRNA SCREEN, WE IDENTIFY THE NRF2 ANTIOXIDANT PATHWAY AS A DRIVER MECHANISM IN HGPS. PROGERIN SEQUESTERS NRF2 AND THEREBY CAUSES ITS SUBNUCLEAR MISLOCALIZATION, RESULTING IN IMPAIRED NRF2 TRANSCRIPTIONAL ACTIVITY AND CONSEQUENTLY INCREASED CHRONIC OXIDATIVE STRESS. SUPPRESSED NRF2 ACTIVITY OR INCREASED OXIDATIVE STRESS IS SUFFICIENT TO RECAPITULATE HGPS AGING DEFECTS, WHEREAS REACTIVATION OF NRF2 ACTIVITY IN HGPS PATIENT CELLS REVERSES PROGERIN-ASSOCIATED NUCLEAR AGING DEFECTS AND RESTORES IN VIVO VIABILITY OF MSCS IN AN ANIMAL MODEL. THESE FINDINGS IDENTIFY REPRESSION OF THE NRF2-MEDIATED ANTIOXIDATIVE RESPONSE AS A KEY CONTRIBUTOR TO THE PREMATURE AGING PHENOTYPE. 2016 5 1274 32 DACH1 PROTECTS PODOCYTES FROM EXPERIMENTAL DIABETIC INJURY AND MODULATES PTIP-H3K4ME3 ACTIVITY. DACHSHUND HOMOLOG 1 (DACH1), A KEY CELL-FATE DETERMINANT, REGULATES TRANSCRIPTION BY DNA SEQUENCE-SPECIFIC BINDING. WE IDENTIFIED DIMINISHED DACH1 EXPRESSION IN A LARGE-SCALE SCREEN FOR MUTATIONS THAT CONVERT INJURY-RESISTANT PODOCYTES INTO INJURY-SUSCEPTIBLE PODOCYTES. IN DIABETIC KIDNEY DISEASE (DKD) PATIENTS, PODOCYTE DACH1 EXPRESSION LEVELS ARE DIMINISHED, A CONDITION THAT STRONGLY CORRELATES WITH POOR CLINICAL OUTCOMES. GLOBAL DACH1 KO MICE MANIFEST RENAL HYPOPLASIA AND DIE PERINATALLY. PODOCYTE-SPECIFIC DACH1 KO MICE, HOWEVER, MAINTAIN NORMAL GLOMERULAR ARCHITECTURE AT BASELINE, BUT RAPIDLY EXHIBIT PODOCYTE INJURY AFTER DIABETES ONSET. FURTHERMORE, PODOCYTE-SPECIFIC AUGMENTATION OF DACH1 EXPRESSION IN MICE PROTECTS FROM DKD. COMBINED RNA SEQUENCING AND IN SILICO PROMOTER ANALYSIS REVEAL CONVERSELY OVERLAPPING GLOMERULAR TRANSCRIPTOMIC SIGNATURES BETWEEN PODOCYTE-SPECIFIC DACH1 AND PAX TRANSACTIVATION-DOMAIN INTERACTING PROTEIN (PTIP) KO MICE, WITH UPREGULATED GENES POSSESSING HIGHER-THAN-EXPECTED NUMBERS OF PROMOTER DACH1-BINDING SITES. PTIP, AN ESSENTIAL COMPONENT OF THE ACTIVATING HISTONE H3 LYSINE 4 TRIMETHYLATION (H3K4ME3) COMPLEX, INTERACTS WITH DACH1 AND IS RECRUITED BY DACH1 TO ITS PROMOTER-BINDING SITES. DACH1-PTIP RECRUITMENT REPRESSES TRANSCRIPTION AND REDUCES PROMOTER H3K4ME3 LEVELS. DACH1 KNOCKDOWN IN PODOCYTES COMBINED WITH HYPERGLYCEMIA TRIGGERS TARGET GENE UPREGULATION AND INCREASES PROMOTER H3K4ME3. THESE FINDINGS REVEAL THAT IN DKD, DIMINISHED DACH1 EXPRESSION ENHANCES PODOCYTE INJURY VULNERABILITY VIA EPIGENETIC DEREPRESSION OF ITS TARGET GENES. 2021 6 1104 29 COMBINED EXPOSURE TO PROTONS AND (56)FE LEADS TO OVEREXPRESSION OF IL13 AND REACTIVATION OF REPETITIVE ELEMENTS IN THE MOUSE LUNG. INTEREST IN DEEP SPACE EXPLORATION UNDERLINES THE NEEDS TO INVESTIGATE THE EFFECTS OF EXPOSURE TO COMBINED SOURCES OF SPACE RADIATION. THE LUNG IS A TARGET ORGAN FOR RADIATION, AND EXPOSURE TO PROTONS AND HEAVY IONS AS RADIATION SOURCES MAY LEAD TO THE DEVELOPMENT OF DEGENERATIVE DISEASE AND CANCER. IN THIS STUDY, WE EVALUATED THE PRO-FIBROTIC AND EPIGENETIC EFFECTS OF EXPOSURE TO PROTONS (150 MEV/NUCLEON, 0.1 GY) AND HEAVY IRON IONS ((56)FE, 600 MEV/NUCLEON, 0.5 GY) ALONE OR IN COMBINATION (PROTONS ON DAY 1 AND (56)FE ON DAY 2) IN C57BL/6 MALE MICE 4 WEEKS AFTER IRRADIATION. EXPOSURE TO (56)FE, PROTON OR IN COMBINATION, DID NOT RESULT IN HISTOPATHOLOGICAL CHANGES IN THE MURINE LUNG. AT THE SAME TIME, COMBINED EXPOSURE TO PROTONS AND (56)FE RESULTED IN PRONOUNCED MOLECULAR ALTERATIONS IN COMPARISON WITH EITHER SOURCE OF RADIATION ALONE. SPECIFICALLY, WE OBSERVED A SUBSTANTIAL INCREASE IN THE EXPRESSION OF CYTOKINE IL13, LOSS OF EXPRESSION OF DNA METHYLTRANSFERASE DNMT1, AND REACTIVATION OF LINE-1, SINE B1 RETROTRANSPOSONS, AND MAJOR AND MINOR SATELLITES. GIVEN THE DELETERIOUS POTENTIAL OF THE OBSERVED EFFECTS THAT MAY LEAD TO DEVELOPMENT OF CHRONIC LUNG INJURY, PULMONARY FIBROSIS, AND CANCER, FUTURE STUDIES DEVOTED TO THE INVESTIGATION OF THE LONG-TERM EFFECTS OF COMBINED EXPOSURES TO PROTON AND HEAVY IONS ARE CLEARLY NEEDED. 2015 7 3526 42 IL-6 AND SIL-6R INDUCES STAT3-DEPENDENT DIFFERENTIATION OF HUMAN VSMCS INTO OSTEOBLAST-LIKE CELLS THROUGH JMJD2B-MEDIATED HISTONE DEMETHYLATION OF RUNX2. INFLAMMATION AND VASCULAR CALCIFICATION ARE INDEPENDENT RISK FACTORS OF CARDIOVASCULAR EVENTS. VASCULAR SMOOTH MUSCLE CELLS (VSMCS) EXHIBIT OSTEOBLAST-LIKE CHARACTERISTICS IN RESPONSE TO VARIOUS STIMULI SUCH AS OXIDIZED CHOLESTEROL AND INFLAMMATION. HOWEVER THE PRECISE MECHANISM OF TRANSCRIPTIONAL REGULATION OF VSMCS BY INFLAMMATORY STIMULI REMAINS UNCLEAR. WE INVESTIGATED THE PROCESS AND MECHANISMS OF INFLAMMATORY CYTOKINE-INDUCED TRANSFORMATION OF HUMAN VSMCS (HVSMCS) INTO OSTEOBLAST-LIKE CELLS, WITH A SPECIAL FOCUS ON EPIGENETIC CHANGES. OUR RESULTS DEMONSTRATED: (1) INTERLEUKIN-6 (IL-6)/SOLUBLE INTERLEUKIN-6 RECEPTOR (SIL-6R) INDUCED TRANSFORMATION OF HVSMCS INTO AN OSTEOBLAST PHENOTYPE, WITH SUBSEQUENT VASCULAR CALCIFICATION, BASED ON THE RESULTS OF ALIZARIN RED S STAINING AND O-CRESOLPHTHALEIN COMPLEXONE METHOD; (2) IL-6/SIL-6R ACCELERATED THE EXPRESSION OF RUNT-RELATED TRANSCRIPTION FACTOR 2 (RUNX2) BASED ON THE RESULTS OF QUANTITATIVE REAL-TIME POLYMERASE CHAIN REACTION; (3) KNOCKDOWN OF SIGNAL TRANSDUCER AND ACTIVATOR OF TRANSCRIPTION (STAT) 3 REDUCED IL-6/SIL-6R-INDUCED RUNX2 MRNA EXPRESSION AND OSTEOBLAST TRANSDIFFERENTIATION OF HVSMCS; (4) CHROMATIN IMMUNOPRECIPITATION (CHIP) COUPLED WITH PCR (CHIP-PCR) IDENTIFIED A STAT-BINDING SITE IN RUNX2 PROMOTER REGION CONTAINING TRIMETHYLATED HISTONE 3 LYSINE 9 (H3K9ME3), A TRANSCRIPTIONAL REPRESSOR, AND H3K4ME3, A TRANSCRIPTIONAL ENHANCER. STIMULATION WITH IL-6/SIL-6R SUPPRESSED H3K9ME3 BUT NOT H3K4ME3 THROUGH THE RECRUITMENT OF JUMONJI DOMAIN-CONTAINING PROTEIN (JMJD) 2B, A HISTONE LYSINE DEMETHYLASE, AT THE STAT-BINDING SITE IN RUNX2 PROMOTER REGION; (5) IL-6/SIL-6R-INDUCED RUNX2 GENE EXPRESSION WAS INHIBITED IN HVSMCS PRETREATED WITH JIB04, JMJD2 INHIBITOR, AND THE INHIBITORY EFFECT WAS JIB04 DOSE-DEPENDENT. OUR RESULTS INDICATE THAT THE IL-6/STAT3/JMJD2B PATHWAY REGULATES HVSMCS DIFFERENTIATION INTO OSTEOBLAST-LIKE CELLS, WHICH SUGGEST ITS PATHOGENIC ROLE IN VASCULAR CALCIFICATION ASSOCIATED WITH CHRONIC INFLAMMATION. 2019 8 3622 29 IN VIVO ANTAGONISTIC ROLE OF THE HUMAN T-CELL LEUKEMIA VIRUS TYPE 1 REGULATORY PROTEINS TAX AND HBZ. ADULT T CELL LEUKEMIA (ATL) IS AN AGGRESSIVE MALIGNANCY SECONDARY TO CHRONIC INFECTION BY THE HUMAN T-CELL LEUKEMIA VIRUS TYPE 1 (HTLV-1) INFECTION. TWO VIRAL PROTEINS, TAX AND HBZ, PLAY CENTRAL ROLES IN ATL LEUKEMOGENESIS. TAX EXPRESSION TRANSFORMS T CELLS IN VITRO AND INDUCES ATL-LIKE DISEASE IN MICE. TAX ALSO INDUCES A ROUGH EYE PHENOTYPE AND INCREASES HEMOCYTE COUNT IN DROSOPHILA MELANOGASTER, INDICATIVE OF TRANSFORMATION. AMONG MULTIPLE FUNCTIONS, TAX MODULATES THE EXPRESSION OF THE ENHANCER OF ZESTE HOMOLOG 2 (EZH2), A METHYLTRANSFERASE OF THE POLYCOMB REPRESSIVE COMPLEX 2 (PRC2), LEADING TO H3K27ME3-DEPENDENT REPROGRAMMING OF AROUND HALF OF CELLULAR GENES. HBZ IS A NEGATIVE REGULATOR OF TAX-MEDIATED VIRAL TRANSCRIPTION. HBZ EFFECTS ON EPIGENETIC SIGNATURES ARE UNDEREXPLORED. HERE, WE ESTABLISHED AN HBZ TRANSGENIC FLY MODEL, AND DEMONSTRATED THAT, UNLIKE TAX, WHICH INDUCES NF-KAPPAB ACTIVATION AND ENHANCED PRC2 ACTIVITY CREATING AN ACTIVATION LOOP, HBZ NEITHER INDUCES TRANSFORMATION NOR NF-KAPPAB ACTIVATION IN VIVO. HOWEVER, OVEREXPRESSION OF TAX OR HBZ INCREASES THE PRC2 ACTIVITY AND BOTH PROTEINS DIRECTLY INTERACT WITH PRC2 COMPLEX CORE COMPONENTS. IMPORTANTLY, OVEREXPRESSION OF HBZ IN TAX TRANSGENIC FLIES PREVENTS TAX-INDUCED NF-KAPPAB OR PRC2 ACTIVATION AND TOTALLY RESCUES TAX-INDUCED TRANSFORMATION AND SENESCENCE. OUR RESULTS ESTABLISH THE IN VIVO ANTAGONISTIC EFFECT OF HBZ ON TAX-INDUCED TRANSFORMATION AND CELLULAR EFFECTS. THIS STUDY HELPS UNDERSTANDING LONG-TERM HTLV-1 PERSISTENCE AND CELLULAR TRANSFORMATION AND OPENS PERSPECTIVES FOR NEW THERAPEUTIC STRATEGIES TARGETING THE EPIGENETIC MACHINERY IN ATL. 2021 9 216 29 ACUTE BETA-ADRENERGIC ACTIVATION TRIGGERS NUCLEAR IMPORT OF HISTONE DEACETYLASE 5 AND DELAYS G(Q)-INDUCED TRANSCRIPTIONAL ACTIVATION. DURING HEMODYNAMIC STRESS, CATECHOLAMINES AND NEUROHUMORAL STIMULI MAY INDUCE CO-ACTIVATION OF G(Q)-COUPLED RECEPTORS AND BETA-ADRENERGIC RECEPTORS (BETA-AR), LEADING TO CARDIAC REMODELING. DYNAMIC REGULATION OF HISTONE DEACETYLASE 5 (HDAC5), A TRANSCRIPTIONAL REPRESSOR, IS CRUCIAL DURING STRESS SIGNALING DUE TO ITS ROLE IN EPIGENETIC CONTROL OF FETAL GENE MARKERS. LITTLE IS KNOWN ABOUT ITS REGULATION DURING ACUTE AND CHRONIC BETA-AR STIMULATION AND ITS CROSS-INTERACTION WITH G(Q) SIGNALING IN ADULT CARDIAC MYOCYTES. HERE, WE EVALUATE THE POTENTIAL CROSS-TALK BETWEEN G(Q)-DRIVEN AND BETA-AR MEDIATED SIGNALING AT THE LEVEL OF NUCLEOCYTOPLASMIC SHUTTLING OF HDAC5. WE SHOW THE TRANSLOCATION OF GFP-TAGGED WILD TYPE HDAC5 OR MUTANTS (S279A AND S279D) IN RESPONSE TO BETA-AR OR G(Q) AGONISTS. ISOPROTERENOL (ISO) OR PKA ACTIVATION RESULTS IN STRONG NUCLEAR ACCUMULATION OF HDAC5 IN CONTRAST TO NUCLEAR EXPORT DRIVEN BY CA(2+)-CALMODULIN PROTEIN KINASE II AND PROTEIN KINASE D. MOREOVER, NUCLEAR ACCUMULATION OF HDAC5 UNDER ACUTE ISO/PKA SIGNALING IS DEPENDENT ON PHOSPHORYLATION OF SER-279 AND CAN BLOCK SUBSEQUENT G(Q)-MEDIATED NUCLEAR HDAC5 EXPORT. INTRIGUINGLY, THE ATTENUATION OF G(Q)-INDUCED EXPORT IS ABOLISHED AFTER CHRONIC PKA ACTIVATION, YET NUCLEAR HDAC5 REMAINS ELEVATED. LAST, THE EFFECT OF CHRONIC BETA-AR SIGNALING ON HDAC5 TRANSLOCATION WAS EXAMINED IN ADULT MYOCYTES FROM A RABBIT MODEL OF HEART FAILURE, WHERE ISO-INDUCED NUCLEAR IMPORT IS ABLATED, BUT G(Q)-AGONIST MEDIATED EXPORT IS PRESERVED. ACUTE BETA-AR/PKA ACTIVATION PROTECTS AGAINST HYPERTROPHIC SIGNALING BY DELAYING G(Q)-MEDIATED TRANSCRIPTIONAL ACTIVATION. THIS SERVES AS A KEY PHYSIOLOGICAL CONTROL SWITCH BEFORE ALLOWING GENETIC REPROGRAMMING VIA HDAC5 NUCLEAR EXPORT DURING MORE SEVERE STRESS, SUCH AS HEART FAILURE. 2013 10 5504 28 RHEIN REVERSAL OF DNA HYPERMETHYLATION-ASSOCIATED KLOTHO SUPPRESSION AMELIORATES RENAL FIBROSIS IN MICE. RENAL FIBROSIS IS THE HALLMARK OF CHRONIC KIDNEY DISEASES (CKD) AND ITS DEVELOPMENT AND PROGRESSION ARE SIGNIFICANTLY AFFECTED BY EPIGENETIC MODIFICATIONS. RHEIN, A PLANT-DERIVED ANTHRAQUINONE, DISPLAYS STRONG ANTI-FIBROSIS PROPERTIES, BUT ITS PROTECTIVE MODE OF ACTION REMAINS INCOMPLETELY UNDERSTOOD. HERE WE EXPLORE THE MECHANISM OF RHEIN ANTI-RENAL FIBROSIS BY INVESTIGATING ITS REGULATION OF KLOTHO, A KNOWN RENAL ANTI-FIBROTIC PROTEIN WHOSE SUPPRESSION AFTER RENAL INJURY REPORTEDLY INVOLVES ABERRANT DNA METHYLATION. WE REPORT THAT RHEIN IS AN IMPRESSIVE UP-REGULATOR OF KLOTHO AND IT MARKEDLY REVERSED KLOTHO DOWN-REGULATION IN UNILATERAL URETERAL OCCLUSION-INDUCED FIBROTIC KIDNEY. FURTHER EXAMINATIONS REVEALED THAT KLOTHO LOSS IN FIBROTIC KIDNEY IS ASSOCIATED WITH KLOTHO PROMOTER HYPERMETHYLATION DUE TO ABERRANT METHYLTRANSFERASE 1 AND 3A EXPRESSIONS. HOWEVER, RHEIN SIGNIFICANTLY CORRECTED ALL THESE EPIGENETIC ALTERATIONS AND SUBSEQUENTLY ALLEVIATED PRO-FIBROTIC PROTEIN EXPRESSION AND RENAL FIBROSIS, WHEREAS KLOTHO KNOCKDOWN VIA RNA INTERFERENCES LARGELY ABROGATED THE ANTI-RENAL FIBROTIC EFFECTS OF RHEIN, SUGGESTING THAT RHEIN EPIGENETIC REVERSAL OF KLOTHO LOSS REPRESENTS A CRITICAL MODE OF ACTION THAT CONFERS RHEIN'S ANTI- RENAL FIBROTIC FUNCTIONS. ALTOGETHER OUR STUDIES UNCOVER A NOVEL HYPOMETHYLATING CHARACTER OF RHEIN IN PREVENTING KLOTHO LOSS AND RENAL FIBROSIS, AND DEMONSTRATE THE EFFICACY OF KLOTHO-TARGETED EPIGENETIC INTERVENTION IN POTENTIAL TREATMENT OF RENAL FIBROSIS-ASSOCIATED KIDNEY DISEASES. 2016 11 4146 24 MECHANISMS REGULATING MUSCLE PROTEIN SYNTHESIS IN CKD. BACKGROUND: CKD INDUCES LOSS OF MUSCLE PROTEINS PARTLY BY SUPPRESSING MUSCLE PROTEIN SYNTHESIS. MUSCLES OF MICE WITH CKD HAVE INCREASED EXPRESSION OF NUCLEOLAR PROTEIN 66 (NO66), AS DO MUSCLE BIOPSY SPECIMENS FROM PATIENTS WITH CKD OR THOSE UNDERGOING HEMODIALYSIS. INFLAMMATION STIMULATES NO66 EXPRESSION AND CHANGES IN NF-KAPPAB MEDIATE THE RESPONSE. METHODS: SUBTOTAL NEPHRECTOMY CREATED A MOUSE MODEL OF CKD WITH BUN >80 MG/DL. CROSSING NO66(FLOX/FLOX) WITH MCK-CRE MICE BRED MUSCLE-SPECIFIC NO66 (MCK-NO66) KNOCKOUT MICE. EXPERIMENTS ASSESSED THE EFFECT OF REMOVING NO66. RESULTS: MUSCLE-SPECIFIC NO66 KNOCKOUT IN MICE BLOCKS CKD-INDUCED LOSS OF MUSCLE MASS AND IMPROVES PROTEIN SYNTHESIS. NO66 SUPPRESSION OF RIBOSOMAL BIOGENESIS VIA DEMETHYLASE ACTIVITY IS THE MECHANISM BEHIND THESE RESPONSES. IN MUSCLE CELLS, EXPRESSION OF NO66, BUT NOT OF DEMETHYLASE-DEAD MUTANT NO66, DECREASED H3K4ME3 AND H3K36ME3 AND SUPPRESSED PRE-RRNA EXPRESSION. KNOCKING OUT NO66 INCREASED THE ENRICHMENT OF H3K4ME3 AND H3K36ME3 ON RIBOSOMAL DNA. IN PRIMARY MUSCLE CELLS AND IN MUSCLES OF MICE WITHOUT NO66, RIBOSOMAL RNA, PRE-RRNA, AND PROTEIN SYNTHESIS ALL INCREASED. CONCLUSIONS: CKD SUPPRESSES MUSCLE PROTEIN SYNTHESIS VIA EPIGENETIC MECHANISMS THAT NO66 MEDIATES. BLOCKING NO66 COULD SUGGEST STRATEGIES THAT COUNTER CKD-INDUCED ABNORMAL MUSCLE PROTEIN CATABOLISM. 2020 12 3306 31 HIGH-PHOSPHATE-INDUCED CALCIFICATION IS RELATED TO SM22ALPHA PROMOTER METHYLATION IN VASCULAR SMOOTH MUSCLE CELLS. HYPERPHOSPHATEMIA IS CLOSELY RELATED TO VASCULAR CALCIFICATION IN PATIENTS WITH CHRONIC KIDNEY DISEASE. VASCULAR SMOOTH MUSCLE CELLS (VSMCS) EXPOSED TO HIGH PHOSPHATE CONCENTRATIONS IN VITRO UNDERGO PHENOTYPIC TRANSITION TO OSTEOBLAST-LIKE CELLS. MECHANISMS UNDERLYING THIS TRANSDIFFERENTIATION ARE NOT CLEAR. IN THIS STUDY WE USED TWO IN VITRO MODELS, HUMAN AORTIC SMOOTH MUSCLE CELLS AND RAT AORTIC RINGS, TO INVESTIGATE THE PHENOTYPIC TRANSITION OF VSMCS INDUCED BY HIGH PHOSPHATE. WE FOUND THAT HIGH PHOSPHATE CONCENTRATION (3.3 MMOL/L) IN THE MEDIUM WAS ASSOCIATED WITH INCREASED DNA METHYLTRANSFERASE ACTIVITY AND METHYLATION OF THE PROMOTER REGION OF SM22ALPHA. THIS WAS ACCOMPANIED BY LOSS OF THE SMOOTH MUSCLE CELL-SPECIFIC PROTEIN SM22ALPHA, GAIN OF THE OSTEOBLAST TRANSCRIPTION FACTOR CBFA1, AND INCREASED ALKALINE PHOSPHATASE ACTIVITY WITH THE SUBSEQUENT IN VITRO CALCIFICATION. THE ADDITION OF A DEMETHYLATING AGENT (PROCAINE) TO THE HIGH-PHOSPHATE MEDIUM REDUCED DNA METHYLTRANSFERASE ACTIVITY AND PREVENTED METHYLATION OF THE SM22ALPHA PROMOTER, WHICH WAS ACCOMPANIED BY AN INCREASE IN SM22ALPHA EXPRESSION AND LESS CALCIFICATION. ADDITIONALLY, DOWNREGULATION OF SM22ALPHA, EITHER BY SIRNA OR BY A METHYL GROUP DONOR (S-ADENOSYL METHIONINE), RESULTED IN OVEREXPRESSION OF CBFA1. IN CONCLUSION, WE DEMONSTRATE THAT METHYLATION OF SM22ALPHA PROMOTER IS AN IMPORTANT EVENT IN VASCULAR SMOOTH MUSCLE CELL CALCIFICATION AND THAT HIGH PHOSPHATE INDUCES THIS EPIGENETIC MODIFICATION. THESE FINDINGS UNCOVER A NEW INSIGHT INTO MECHANISMS BY WHICH HIGH PHOSPHATE CONCENTRATION PROMOTES VASCULAR CALCIFICATION. 2010 13 2887 28 GADD45A TRANSCRIPTIONAL INDUCTION ELICITED BY THE AURORA KINASE INHIBITOR MK-0457 IN BCR-ABL-EXPRESSING CELLS IS DRIVEN BY OCT-1 TRANSCRIPTION FACTOR. THE ADVANTAGE OF AURORA KINASE (AK) INHIBITORS IN CHRONIC MYELOID LEUKEMIA (CML) THERAPY MOSTLY ARISES FROM "OFF-TARGET" EFFECTS ON TYROSINE KINASE (TK) ACTIVITY OF WILD TYPE (WT) OR MUTATED BCR-ABL PROTEINS WHICH DRIVE THE DISEASE RESISTANCE TO IMATINIB (IM). WE PROVED THAT THE AK INHIBITOR MK-0457 INDUCES THE GROWTH ARREST DNA DAMAGE-INDUCIBLE (GADD) 45A THROUGH RECRUITMENT OF OCTAMER-BINDING (OCT)-1 TRANSCRIPTION FACTOR AT A CRITICAL PROMOTER REGION FOR GENE TRANSCRIPTION AND COVALENT MODIFICATIONS OF HISTONE H3 (LYSINE 14 ACETYLATION, LYSINE 9 DE-METHYLATION). SUCH EPIGENETIC CHROMATIN MODIFICATIONS MAY DEPICT A GENERAL MECHANISM PROMOTING THE RE-ACTIVATION OF TUMOR SUPPRESSOR GENES SILENCED BY BCR-ABL. 2012 14 6012 21 THE APKC-CBP PATHWAY REGULATES POST-STROKE NEUROVASCULAR REMODELING AND FUNCTIONAL RECOVERY. EPIGENETIC MODIFICATIONS HAVE EMERGED AS ATTRACTIVE MOLECULAR SUBSTRATES THAT INTEGRATE EXTRINSIC CHANGES INTO THE DETERMINATION OF CELL IDENTITY. SINCE STROKE-RELATED BRAIN DAMAGE RELEASES MICRO-ENVIRONMENTAL CUES, WE EXAMINED THE ROLE OF A SIGNALING-INDUCED EPIGENETIC PATHWAY, AN ATYPICAL PROTEIN KINASE C (APKC)-MEDIATED PHOSPHORYLATION OF CREB-BINDING PROTEIN (CBP), IN POST-STROKE NEUROVASCULAR REMODELING. USING A KNOCKIN MOUSE STRAIN (CBPS436A) WHERE THE APKC-CBP PATHWAY WAS DEFECTIVE, WE SHOW THAT DISRUPTION OF THE APKC-CBP PATHWAY IN A MURINE FOCAL ISCHEMIC STROKE MODEL INCREASES THE REPROGRAMMING EFFICIENCY OF ISCHEMIA-ACTIVATED PERICYTES (I-PERICYTES) TO NEURAL PRECURSORS. AS A CONSEQUENCE OF ENHANCED CELLULAR REPROGRAMMING, CBPS436A MICE SHOW AN INCREASED TRANSIENT POPULATION OF LOCALLY DERIVED NEURAL PRECURSORS AFTER STROKE, WHILE DISPLAYING A REDUCED NUMBER OF I-PERICYTES, IMPAIRED VASCULAR REMODELING, AND PERTURBED MOTOR RECOVERY DURING THE CHRONIC PHASE OF STROKE. TOGETHER, THIS STUDY ELUCIDATES THE ROLE OF THE APKC-CBP PATHWAY IN MODULATING NEUROVASCULAR REMODELING AND FUNCTIONAL RECOVERY FOLLOWING FOCAL ISCHEMIC STROKE. 2017 15 3237 37 HEPATIC COX-2 EXPRESSION PROTECTS MICE FROM AN ALCOHOL-HIGH FAT DIET-INDUCED METABOLIC DISORDER BY INVOLVING PROTEIN ACETYLATION RELATED ENERGY METABOLISM. PURPOSE: A DIET HIGH IN FAT AND ETHANOL OFTEN RESULTS IN CHRONIC METABOLIC DISORDER, HEPATIC STEATOSIS, AND LIVER INFLAMMATION. CONSTITUTIVE HEPATIC CYCLOOXYGENASE-2 (COX-2) EXPRESSION COULD PROTECT FROM HIGH FAT-INDUCED METABOLISM DISTURBANCE IN A MURINE MODEL. IN THIS STUDY, WE EXPLORED THE INFLUENCE OF HCOX-2 TRANSGENIC [TG] TO HIGH FAT WITH ETHANOL-INDUCED METABOLIC DISORDER AND LIVER INJURY USING A MOUSE ANIMAL MODEL. METHODS: 12-WEEK-OLD MALE HEPATIC HCOX-2 TRANSGENIC (TG) OR WILD TYPE MICE (WT) WERE FED EITHER A HIGH FAT AND ETHANOL LIQUID DIET (HF+ETH) OR A REGULAR CONTROL DIET (RCD) FOR 5 WEEKS (FOUR GROUPS: RCD/WT, RCD/TG; HF+ETH/TG, HF+ETH/WT). WE ASSESSED METABOLIC BIOMARKERS, CYTOKINE PROFILES, HISTOMORPHOLOGY, AND GENE EXPRESSION TO STUDY THE IMPACT OF PERSISTENT HEPATIC COX-2 EXPRESSION ON DIET-INDUCED LIVER INJURY. RESULTS: IN THE HF+ETH DIET, CONSTITUTIVELY HEPATIC HUMAN COX-2 EXPRESSION PROTECTS MICE FROM BODY WEIGHT GAIN AND WHITE ADIPOSE TISSUE ACCUMULATION, ACCOMPANIED BY IMPROVED IPGTT RESPONSE, SERUM TRIGLYCERIDE/CHOLESTEROL LEVELS, AND LOWER LEVELS OF SERUM AND LIVER INFLAMMATORY CYTOKINES. HISTOLOGICALLY, HCOX-2 MICE SHOWED DECREASED HEPATIC LIPID DROPLETS ACCUMULATION, DECREASED HEPATOCYTE BALLOONING, AND IMPROVED STEATOSIS SCORES. HEPATIC HCOX-2 OVEREXPRESSION ENHANCED AKT INSULIN SIGNALING AND INCREASED FATTY ACID SYNTHESIS IN BOTH RCD AND HF+ETH DIET GROUPS. THE ANTI-LIPOGENIC EFFECT OF HCOX-2 TG IN THE HF+ETH DIET ANIMALS WAS MEDIATED BY INCREASING LIPID DISPOSAL THROUGH ENHANCED BETA-OXIDATION VIA ELEVATIONS IN THE EXPRESSION OF PPARALPHA AND PPARGAMMA, AND INCREASED HEPATIC AUTOPHAGY AS ASSESSED BY THE RATIO OF AUTOPHAGY MARKERS LC3 II/I IN HEPATIC TISSUE. VARIOUS PROTEIN ACETYLATION PATHWAY COMPONENTS, INCLUDING HAT, HDAC1, SIRT1, AND SNAIL1, WERE MODULATED IN HCOX-2 TG MICE IN EITHER RCD OR HF+ETH DIET. CONCLUSIONS: HEPATIC HUMAN COX-2 EXPRESSION PROTECTED MICE FROM THE METABOLIC DISORDER AND LIVER INJURY INDUCED BY A HIGH FAT AND ETHANOL DIET BY ENHANCING HEPATIC LIPID EXPENDITURE. EPIGENETIC REPROGRAMMING OF DIVERSE METABOLIC GENES MIGHT BE INVOLVED IN THE ANTI-LIPOGENIC EFFECT OF COX-2. 2021 16 5990 24 TGF-BETA1 PROMOTES EXPRESSION OF FIBROSIS-RELATED GENES THROUGH THE INDUCTION OF HISTONE VARIANT H3.3 AND HISTONE CHAPERONE HIRA. RENAL FIBROSIS IS A HISTOLOGICAL MANIFESTATION THAT OCCURS IN ALMOST EVERY TYPE OF CHRONIC KIDNEY DISEASE. HISTONE VARIANT H3.3 AND ITS CHAPERONE, HISTONE CELL CYCLE REGULATION DEFECTIVE HOMOLOG A (HIRA), SERVE AS EPIGENETIC MARKS THAT REGULATE TRANSCRIPTIONAL ACTIVITY. IN THIS STUDY, WE ASSESSED THE ROLES OF HISTONE H3.3 AND HIRA IN UNILATERAL URETERAL-OBSTRUCTION (UUO) MICE. IN UUO MICE, THE LEVELS OF HISTONE H3.3 AND HIRA WERE SIGNIFICANTLY UPREGULATED IN THE KIDNEYS. THESE UPREGULATED LEVELS WERE DECREASED BY A TGF-BETA1 NEUTRALIZING ANTIBODY. TGF-BETA1 INDUCED HISTONE H3.3 AND HIRA EXPRESSION IN VITRO VIA A SMAD3-DEPENDENT PATHWAY IN NORMAL RAT KIDNEY (NRK)-52E CELLS. ADDITIONALLY, KNOCKDOWN OF HIRA EXPRESSION DECREASED HISTONE H3.3 EXPRESSION AND FIBROGENESIS IN NRK-52E CELLS AFTER TGF-BETA1 STIMULATION. CHROMATIN IMMUNOPRECIPITATION ANALYSIS REVEALED THAT PROMOTERS OF FIBROSIS-RELATED GENES WERE IMMUNOPRECIPITATED WITH BOTH HISTONE H3.3 AND HIRA IN NRK-52E CELLS. LASTLY, IN HUMAN KIDNEY BIOPSIES FROM PATIENTS DIAGNOSED WITH IGA NEPHROPATHY, HISTONE H3.3 AND HIRA IMMUNOSTAINING CORRELATED POSITIVELY WITH AREAS OF FIBROSIS AND ESTIMATED GLOMERULAR FILTRATION RATE. IN CONCLUSION, TGF-BETA1 INDUCES EXPRESSION OF HISTONE H3.3 AND HIRA, WHICH REGULATES EXPRESSION OF FIBROSIS-RELATED GENES. 2018 17 5096 24 PLASMODIUM FALCIPARUM SET2 DOMAIN IS ALLOSTERICALLY REGULATED BY ITS PHD-LIKE DOMAIN TO METHYLATE AT H3K36. THE ANTIGENIC VARIATION IS AN ESSENTIAL MECHANISM EMPLOYED BY THE MALARIA PARASITE TO ESTABLISH A CHRONIC INFECTION IN HUMANS. THREE MAJOR VIRULENT PROTEINS EMP1, RIFINS, AND STEVOR HAVE BEEN IMPLICATED IN CONTRIBUTING TO THE ANTIGENIC VARIATION PROCESS AND ARE ENCODED BY MULTIGENE FAMILIES IN PLASMODIUM SPP. THE KEY VIRULENCE FACTOR PFEMP1 IS ENCODED BY VAR GENES, AND IT EXHIBITS A MUTUALLY EXCLUSIVE TRANSCRIPTIONAL SWITCHING BETWEEN VAR GENES, ENSURING AN INDIVIDUAL PARASITE ONLY TRANSCRIBES A SINGLE VAR GENE AT A TIME. EXPRESSION OF VAR GENES IS TIGHTLY REGULATED BY TWO HISTONE EPIGENETIC METHYLATION MARKS H3K36ME3 AND H3K9ME3, OF WHICH THE H3K36ME3 MARK IS HIGHLY ENRICHED ON TRANSCRIPTION START SITES (TSSS) OF SUPPRESSED VAR GENES IN P. FALCIPARUM. HOWEVER, THE MECHANISMS OF H3K36ME3 MARK PROPAGATION ON ALL THE 59 VAR GENES OF P. FALCIPARUM ARE NOT KNOWN. HERE, WE HAVE IDENTIFIED A PHD (PLANT HOMEODOMAIN-LIKE DOMAIN) LIKE DOMAIN PRESENT WITHIN THE PFSET2 PROTEIN THAT SPECIFICALLY BINDS TO THE H3K36ME2 MARK, AN INTERMEDIATE PRODUCT OF THE H3K36ME3 MARK FORMATION ON THE NUCLEOSOME. SURPRISINGLY, WE HAVE FOUND THAT PHD - H3K36ME2 INTERACTION LEADS TO STIMULATION OF SET2 DOMAIN ACTIVITY ON THE NUCLEOSOME SUBSTRATES. THE ALLOSTERIC STIMULATION OF THE PFSET2 DOMAIN BY PHD-LIKE DOMAIN PRESENT WITHIN THE SAME PROTEIN SUGGESTS A NOVEL MECHANISM OF H3K36ME3 MARK PROPAGATION ON VAR GENES OF P. FALCIPARUM. THIS STUDY PROPOSES ALLOSTERIC REGULATION OF PFSET2 PROTEIN BY H3K36ME2 MARK AS AN ESSENTIAL MECHANISM OF VAR GENES SUPPRESSION TO ENSURE SUCCESSFUL ANTIGENIC VARIATION BY THE MALARIA PARASITE. 2021 18 4226 19 METHYLATION IN PERICYTES AFTER ACUTE INJURY PROMOTES CHRONIC KIDNEY DISEASE. THE ORIGIN AND FATE OF RENAL MYOFIBROBLASTS IS NOT CLEAR AFTER ACUTE KIDNEY INJURY (AKI). HERE, WE DEMONSTRATE THAT MYOFIBROBLASTS WERE ACTIVATED FROM QUIESCENT PERICYTES (QPERICYTES) AND THE CELL NUMBERS INCREASED AFTER ISCHEMIA/REPERFUSION INJURY-INDUCED AKI (IRI-AKI). MYOFIBROBLASTS UNDERWENT APOPTOSIS DURING RENAL RECOVERY BUT ONE-FIFTH OF THEM SURVIVED IN THE RECOVERED KIDNEYS ON DAY 28 AFTER IRI-AKI AND THEIR CELL NUMBERS INCREASED AGAIN AFTER DAY 56. MICROARRAY DATA SHOWED THE DISTINCTIVE GENE EXPRESSION PATTERNS OF QPERICYTES, ACTIVATED PERICYTES (APERICYTES, MYOFIBROBLASTS), AND INACTIVATED PERICYTES (IPERICYTES) ISOLATED FROM KIDNEYS BEFORE, ON DAY 7, AND ON DAY 28 AFTER IRI-AKI. HYPERMETHYLATION OF THE ACTA2 REPRESSOR YBX2 DURING IRI-AKI RESULTED IN EPIGENETIC MODIFICATION OF IPERICYTES TO PROMOTE THE TRANSITION TO CHRONIC KIDNEY DISEASE (CKD) AND AGGRAVATED FIBROGENESIS INDUCED BY A SECOND AKI INDUCED BY ADENINE. MECHANISTICALLY, TRANSFORMING GROWTH FACTOR-BETA1 DECREASED THE BINDING OF YBX2 TO THE PROMOTER OF ACTA2 AND INDUCED YBX2 HYPERMETHYLATION, THEREBY INCREASING ALPHA-SMOOTH MUSCLE ACTIN EXPRESSION IN APERICYTES. DEMETHYLATION BY 5-AZACYTIDINE RECOVERED THE MICROVASCULAR STABILIZING FUNCTION OF APERICYTES, REVERSED THE PROFIBROTIC PROPERTY OF IPERICYTES, PREVENTED AKI-CKD TRANSITION, AND ATTENUATED FIBROGENESIS INDUCED BY A SECOND ADENINE-AKI. IN CONCLUSION, INTERVENTION TO ERASE HYPERMETHYLATION OF PERICYTES AFTER AKI PROVIDES A STRATEGY TO STOP THE TRANSITION TO CKD. 2020 19 1675 31 DRP1-MEDIATED MITOCHONDRIAL FISSION PROMOTES RENAL FIBROBLAST ACTIVATION AND FIBROGENESIS. EXCESSIVE MITOCHONDRIAL FISSION ACTS AS A PRO-PROLIFERATIVE MARKER IN SOME CANCERS AND ORGAN FIBROSIS; ITS POTENTIAL ROLE IN RENAL FIBROBLAST ACTIVATION AND FIBROGENESIS HAS NEVER BEEN INVESTIGATED. HERE, WE SHOWED MORE PRONOUNCED FRAGMENTED MITOCHONDRIA IN FIBROTIC THAN IN NON-FIBROTIC RENAL FIBROBLAST IN HUMANS AND MICE. IN A MOUSE MODEL OF OBSTRUCTIVE NEPHROPATHY, PHOSPHORYLATION OF DRP1 AT SERINE 616 (P-DRP1S616) AND ACETYLATION OF H3K27(H3K27AC) WAS INCREASED IN FIBROTIC KIDNEYS; PHARMACOLOGICAL INHIBITION OF MITOCHONDRIAL FISSION BY MDIVI-1 SUBSTANTIALLY REDUCED H3K27AC LEVELS, FIBROBLASTS ACCUMULATION, AND INTERSTITIAL FIBROSIS. MOREOVER, MDIVI-1 TREATMENT WAS ABLE TO ATTENUATE THE ESTABLISHED RENAL FIBROSIS. IN CULTURED RENAL INTERSTITIAL FIBROBLASTS, TARGETING DRP1 USING PHARMACOLOGICAL INHIBITOR OR SIRNA SUPPRESSED TGF-BETA1-ELICITED CELL ACTIVATION AND PROLIFERATION, AS EVIDENCED BY INHIBITING EXPRESSION OF ALPHA-SMOOTH MUSCLE ACTIN (ALPHA-SMA) AND COLLAGEN I, AS WELL AS BY REDUCING DNA SYNTHESIS. IN CONTRAST, DRP1 DELETION ENHANCED CELL APOPTOSIS, ALONG WITH DECREASED MITOCHONDRIAL FRAGMENTATION, MTROS ELEVATION, AND GLYCOLYTIC SHIFT UPON TGF-BETA1 STIMULATION. IN DRP1 DELETION FIBROBLASTS, RE-EXPRESSION OF WILD-TYPE DRP1 RATHER THAN DRP1S616A MUTANT RESTORES THE REDUCTION OF TGF-BETA-INDUCED-DRP1 PHOSPHORYLATION, H3K27AC, AND CELL ACTIVATION. MOREOVER, TGF-BETA1 TREATMENT INCREASED THE ENRICHMENT OF H3K27AC AT THE PROMOTERS OF ALPHA-SMA AND PCNA, WHICH WAS REVERSED IN DRP1-KNOCKDOWN FIBROBLASTS CO-TRANSFECTED WITH EMPTY VECTOR OR DRP1S616A, BUT NOT WILD-TYPE DRP1. COLLECTIVELY, OUR RESULTS IMPLY THAT INHIBITING P-DRP1S616-MEDIATED MITOCHONDRIAL FISSION ATTENUATES FIBROBLAST ACTIVATION AND PROLIFERATION IN RENAL FIBROSIS THROUGH EPIGENETIC REGULATION OF FIBROSIS-RELATED GENES TRANSCRIPTION AND MAY SERVE AS A THERAPEUTIC TARGET FOR RETARDING PROGRESSION OF CHRONIC KIDNEY DISEASE. 2020 20 6037 20 THE CHD6 CHROMATIN REMODELER IS AN OXIDATIVE DNA DAMAGE RESPONSE FACTOR. CELL SURVIVAL AFTER OXIDATIVE DNA DAMAGE REQUIRES SIGNALING, REPAIR AND TRANSCRIPTIONAL EVENTS OFTEN ENABLED BY NUCLEOSOME DISPLACEMENT, EXCHANGE OR REMOVAL BY CHROMATIN REMODELING ENZYMES. HERE, WE SHOW THAT CHROMODOMAIN HELICASE DNA-BINDING PROTEIN 6 (CHD6), DISTINCT TO OTHER CHD ENZYMES, IS STABILIZED DURING OXIDATIVE STRESS VIA REDUCED DEGRADATION. CHD6 RELOCATES RAPIDLY TO DNA DAMAGE IN A MANNER DEPENDENT UPON OXIDATIVE LESIONS AND A CONSERVED N-TERMINAL POLY(ADP-RIBOSE)-DEPENDENT RECRUITMENT MOTIF, WITH LATER RETENTION REQUIRING THE DOUBLE CHROMODOMAIN AND CENTRAL CORE. CHD6 ABLATION INCREASES REACTIVE OXYGEN SPECIES PERSISTENCE AND IMPAIRS ANTI-OXIDANT TRANSCRIPTIONAL RESPONSES, LEADING TO ELEVATED DNA BREAKAGE AND POLY(ADP-RIBOSE) INDUCTION THAT CANNOT BE RESCUED BY CATALYTIC OR DOUBLE CHROMODOMAIN MUTANTS. DESPITE NO OVERT EPIGENETIC OR DNA REPAIR ABNORMALITIES, CHD6 LOSS LEADS TO IMPAIRED CELL SURVIVAL AFTER CHRONIC OXIDATIVE STRESS, ABNORMAL CHROMATIN RELAXATION, AMPLIFIED DNA DAMAGE SIGNALING AND CHECKPOINT HYPERSENSITIVITY. WE SUGGEST THAT CHD6 IS A KEY REGULATOR OF THE OXIDATIVE DNA DAMAGE RESPONSE. 2019