1 6012 98 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 2 984 27 CHRONIC PSYCHOLOGICAL STRESS ALTERS GENE EXPRESSION IN RAT COLON EPITHELIAL CELLS PROMOTING CHROMATIN REMODELING, BARRIER DYSFUNCTION AND INFLAMMATION. CHRONIC STRESS IS COMMONLY ASSOCIATED WITH ENHANCED ABDOMINAL PAIN (VISCERAL HYPERSENSITIVITY), BUT THE CELLULAR MECHANISMS UNDERLYING HOW CHRONIC STRESS INDUCES VISCERAL HYPERSENSITIVITY ARE POORLY UNDERSTOOD. IN THIS STUDY, WE EXAMINED CHANGES IN GENE EXPRESSION IN COLON EPITHELIAL CELLS FROM A RAT MODEL USING RNA-SEQUENCING TO EXAMINE STRESS-INDUCED CHANGES TO THE TRANSCRIPTOME. FOLLOWING CHRONIC STRESS, THE MOST SIGNIFICANTLY UP-REGULATED GENES INCLUDED ATG16L1, COQ10B, DCAF13, NAT2, PTBP2, RRAS2, SPINK4 AND DOWN-REGULATED GENES INCLUDING ABAT, CITED2, CNNM2, DAB2IP, PLEKHM1, SCD2, AND TAB2. THE PRIMARY ALTERED BIOLOGICAL PROCESSES REVEALED BY NETWORK ENRICHMENT ANALYSIS WERE INFLAMMATION/IMMUNE RESPONSE, TISSUE MORPHOGENESIS AND DEVELOPMENT, AND NUCLEOSOME/CHROMATIN ASSEMBLY. THE MOST SIGNIFICANTLY DOWN-REGULATED PROCESS WAS THE DIGESTIVE SYSTEM DEVELOPMENT/FUNCTION, WHEREAS THE MOST SIGNIFICANTLY UP-REGULATED PROCESSES WERE INFLAMMATORY RESPONSE, ORGANISMAL INJURY, AND CHROMATIN REMODELING MEDIATED BY H3K9 METHYLATION. FURTHERMORE, A SUBPOPULATION OF STRESSED RATS DEMONSTRATED VERY SIGNIFICANTLY ALTERED GENE EXPRESSION AND TRANSCRIPT ISOFORMS, ENRICHED FOR THE DIFFERENTIAL EXPRESSION OF GENES INVOLVED IN THE INFLAMMATORY RESPONSE, INCLUDING UPREGULATION OF CYTOKINE AND CHEMOKINE RECEPTOR GENE EXPRESSION COUPLED WITH DOWNREGULATION OF EPITHELIAL ADHERENS AND TIGHT JUNCTION MRNAS. IN SUMMARY, THESE FINDINGS SUPPORT THAT CHRONIC STRESS IS ASSOCIATED WITH INCREASED LEVELS OF CYTOKINES AND CHEMOKINES, THEIR DOWNSTREAM SIGNALING PATHWAYS COUPLED TO DYSREGULATION OF INTESTINAL CELL DEVELOPMENT AND FUNCTION. EPIGENETIC REGULATION OF CHROMATIN REMODELING LIKELY PLAYS A PROMINENT ROLE IN THIS PROCESS. RESULTS ALSO SUGGEST THAT SUPER ENHANCERS PLAY A PRIMARY ROLE IN CHRONIC STRESS-ASSOCIATED INTESTINAL BARRIER DYSFUNCTION. 2022 3 5153 16 PPP2R2B HYPERMETHYLATION CAUSES ACQUIRED APOPTOSIS DEFICIENCY IN SYSTEMIC AUTOIMMUNE DISEASES. CHRONIC INFLAMMATION CAUSES TARGET ORGAN DAMAGE IN PATIENTS WITH SYSTEMIC AUTOIMMUNE DISEASES. THE FACTORS THAT ALLOW THIS PROTRACTED RESPONSE ARE POORLY UNDERSTOOD. WE ANALYZED THE TRANSCRIPTIONAL REGULATION OF PPP2R2B (B55SS), A MOLECULE NECESSARY FOR THE TERMINATION OF THE IMMUNE RESPONSE, IN PATIENTS WITH AUTOIMMUNE DISEASES. ALTERED EXPRESSION OF B55SS CONDITIONED RESISTANCE TO CYTOKINE WITHDRAWAL-INDUCED DEATH (CWID) IN PATIENTS WITH AUTOIMMUNE DISEASES. THE IMPAIRED UPREGULATION OF B55SS WAS CAUSED BY INFLAMMATION-DRIVEN HYPERMETHYLATION OF SPECIFIC CYTOSINES LOCATED WITHIN A REGULATORY ELEMENT OF PPP2R2B PREVENTING CTCF BINDING. THIS PHENOTYPE COULD BE INDUCED IN HEALTHY T CELLS BY EXPOSURE TO TNF-ALPHA. OUR RESULTS REVEAL A GENE WHOSE EXPRESSION IS AFFECTED BY AN ACQUIRED DEFECT, THROUGH AN EPIGENETIC MECHANISM, IN THE SETTING OF SYSTEMIC AUTOIMMUNITY. BECAUSE FAILURE TO REMOVE ACTIVATED T CELLS THROUGH CWID COULD CONTRIBUTE TO AUTOIMMUNE PATHOLOGY, THIS MECHANISM ILLUSTRATES A VICIOUS CYCLE THROUGH WHICH AUTOIMMUNE INFLAMMATION CONTRIBUTES TO ITS OWN PERPETUATION. 2019 4 3327 25 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 5 3096 23 GENOMIC CHARACTERIZATION REVEALS NOVEL MECHANISMS UNDERLYING THE VALOSIN-CONTAINING PROTEIN-MEDIATED CARDIAC PROTECTION AGAINST HEART FAILURE. CHRONIC HYPERTENSION IS A KEY RISK FACTOR FOR HEART FAILURE. HOWEVER, THE UNDERLYING MOLECULAR MECHANISMS ARE NOT FULLY UNDERSTOOD. OUR PREVIOUS STUDIES FOUND THAT THE VALOSIN-CONTAINING PROTEIN (VCP), AN ATPASE-ASSOCIATED PROTEIN, WAS SIGNIFICANTLY DECREASED IN THE HYPERTENSIVE HEART TISSUES. IN THIS STUDY, WE TESTED THE HYPOTHESIS THAT RESTORATION OF VCP PROTECTED THE HEART AGAINST PRESSURE OVERLOAD-INDUCED HEART FAILURE. WITH A CARDIAC-SPECIFIC TRANSGENIC (TG) MOUSE MODEL, WE SHOWED THAT A MODERATE INCREASE OF VCP WAS ABLE TO ATTENUATE CHRONIC PRESSURE OVERLOAD-INDUCED MALADAPTIVE CARDIAC HYPERTROPHY AND DYSFUNCTION. RNA SEQUENCING AND A COMPREHENSIVE BIOINFORMATIC ANALYSIS FURTHER DEMONSTRATED THAT OVEREXPRESSION OF VCP IN THE HEART NORMALIZED THE PRESSURE OVERLOAD-STIMULATED HYPERTROPHIC SIGNALS AND REPRESSED THE STRESS-INDUCED INFLAMMATORY RESPONSE. IN ADDITION, VCP OVEREXPRESSION PROMOTED CELL SURVIVAL BY ENHANCING THE MITOCHONDRIA RESISTANCE TO THE OXIDATIVE STRESS VIA ACTIVATING THE RICTOR-MEDIATED-GENE NETWORKS. VCP WAS ALSO FOUND TO BE INVOLVED IN THE REGULATION OF THE ALTERNATIVE SPLICING AND DIFFERENTIAL ISOFORM EXPRESSION FOR SOME GENES THAT ARE RELATED TO ATP PRODUCTION AND PROTEIN SYNTHESIS BY INTERACTING WITH LONG NO-CODING RNAS AND HISTONE DEACETYLASES, INDICATING A NOVEL EPIGENETIC REGULATION OF VCP IN INTEGRATING CODING AND NONCODING GENOMIC NETWORK IN THE STRESSED HEART. IN SUMMARY, OUR STUDY DEMONSTRATED THAT THE RESCUING OF A DEFICIENT VCP IN THE HEART COULD PREVENT PRESSURE OVERLOAD-INDUCED HEART FAILURE BY RECTIFYING CARDIAC HYPERTROPHIC AND INFLAMMATORY SIGNALING AND ENHANCING THE CARDIAC RESISTANCE TO OXIDATIVE STRESS, WHICH BROUGHT IN NOVEL INSIGHTS INTO THE UNDERSTANDING OF THE MECHANISM OF VCP IN PROTECTING PATIENTS FROM HYPERTENSIVE HEART FAILURE. 2020 6 3390 25 HOPX PLAYS A CRITICAL ROLE IN ANTIRETROVIRAL DRUGS INDUCED EPIGENETIC MODIFICATION AND CARDIAC HYPERTROPHY. PEOPLE LIVING WITH HIV (PLWH) HAVE TO TAKE AN ANTIRETROVIRAL THERAPY (ART) FOR LIFE AND SHOW NONCOMMUNICABLE ILLNESSES SUCH AS CHRONIC INFLAMMATION, IMMUNE ACTIVATION, AND MULTIORGAN DYSREGULATION. RECENT STUDIES SUGGEST THAT LONG-TERM USE OF ART INDUCES COMORBID CONDITIONS AND IS ONE OF THE LEADING CAUSES OF HEART FAILURE IN PLWH. HOWEVER, THE MOLECULAR MECHANISM OF ANTIRETROVIRAL DRUGS (ARVS) INDUCED HEART FAILURE IS UNCLEAR. TO DETERMINE THE MECHANISM OF ARVS INDUCED CARDIAC DYSFUNCTION, WE PERFORMED GLOBAL TRANSCRIPTOMIC PROFILING OF ARVS TREATED NEONATAL RAT VENTRICULAR CARDIOMYOCYTES IN CULTURE. DIFFERENTIALLY EXPRESSED GENES WERE IDENTIFIED BY RNA-SEQUENCING. OUR DATA SHOW THAT ARVS TREATMENT CAUSES UPREGULATION OF SEVERAL BIOLOGICAL FUNCTIONS ASSOCIATED WITH CARDIOTOXICITY, HYPERTROPHY, AND HEART FAILURE. GLOBAL GENE EXPRESSION DATA WERE VALIDATED IN CARDIAC TISSUE ISOLATED FROM HIV PATIENTS HAVING A HISTORY OF ART. INTERESTINGLY, WE FOUND THAT HOMEODOMAIN-ONLY PROTEIN HOMEOBOX (HOPX) EXPRESSION WAS SIGNIFICANTLY INCREASED IN CARDIOMYOCYTES TREATED WITH ARVS AND IN THE HEART TISSUE OF HIV PATIENTS. FURTHERMORE, WE FOUND THAT HOPX PLAYS A CRUCIAL ROLE IN ARVS MEDIATED CELLULAR HYPERTROPHY. MECHANISTICALLY, WE FOUND THAT HOPX PLAYS A CRITICAL ROLE IN EPIGENETIC REGULATION, THROUGH DEACETYLATION OF HISTONE, WHILE THE HDAC INHIBITOR, TRICHOSTATIN A, CAN RESTORE THE ACETYLATION LEVEL OF HISTONE 3 IN THE PRESENCE OF ARVS. 2021 7 3465 22 HYPOTHESIS: REGULATION OF NEUROPLASTICITY MAY INVOLVE I-MOTIF AND G-QUADRUPLEX DNA FORMATION MODULATED BY EPIGENETIC MECHANISMS. RECENT STUDIES DEMONSTRATED THE EXISTENCE IN VIVO OF VARIOUS FUNCTIONAL DNA STRUCTURES THAT DIFFER FROM THE DOUBLE HELIX. THE G-QUADRUPLEX (G4) AND INTERCALATED MOTIF (I-MOTIF OR IM) DNA STRUCTURES ARE FORMED AS KNOTS WHERE, CORRESPONDINGLY, GUANINES OR CYTOSINES ON THE SAME STRAND OF DNA BIND TO EACH OTHER. THERE ARE GROUNDS TO BELIEVE THAT G4 AND IM SEQUENCES PLAY A SIGNIFICANT ROLE IN REGULATING GENE EXPRESSION CONSIDERING THEIR TENDENCY TO BE FOUND IN OR NEAR REGULATORY SITES (SUCH AS PROMOTERS, ENHANCERS, AND TELOMERES) AS WELL AS THE CORRELATION BETWEEN THE PREVALENCE OF G4 OR IM CONFORMATIONS AND SPECIFIC PHASES OF CELL CYCLE. NOTABLY, G4 AND IM CAPABLE SEQUENCES TEND TO BE FOUND ON THE OPPOSITE STRANDS OF THE SAME DNA SITE WITH AT MOST ONE OF THE TWO STRUCTURES FORMED AT ANY GIVEN TIME. THE RECENT EVIDENCE THAT K(+), MG(2+) CONCENTRATIONS DIRECTLY AFFECT IM FORMATION (AND LIKELY G4 FORMATION INDIRECTLY) LEAD US TO BELIEVE THAT THESE STRUCTURES MAY PLAY A MAJOR ROLE IN SYNAPTIC PLASTICITY OF NEURONS, AND, THEREFORE, IN A VARIETY OF CENTRAL NERVOUS SYSTEM (CNS) FUNCTIONS INCLUDING MEMORY, LEARNING, HABITUAL BEHAVIORS, PAIN PERCEPTION AND OTHERS. FURTHERMORE, EPIGENETIC MECHANISMS, WHICH HAVE AN IMPORTANT ROLE IN SYNAPTIC PLASTICITY AND MEMORY FORMATION, WERE ALSO SHOWN TO INFLUENCE FORMATION AND STABILITY OF G4S AND IMS. OUR HYPOTHESIS IS THAT NON-CANONICAL DNA AND RNA STRUCTURES COULD BE AN INTEGRAL PART OF NEUROPLASTICITY CONTROL VIA GENE EXPRESSION REGULATION AT THE LEVEL OF TRANSCRIPTION, TRANSLATION AND SPLICING. WE PROPOSE THAT THE REGULATORY ACTIVITY OF DNA IM AND G4 STRUCTURES IS MODULATED BY DNA METHYLATION/DEMETHYLATION OF THE IM AND/OR G4 SEQUENCES, WHICH FACILITATES THE SWITCH BETWEEN CANONICAL AND NON-CANONICAL CONFORMATION. OTHER NEURONAL MECHANISMS INTERACTING WITH THE FORMATION AND REGULATORY ACTIVITY OF NON-CANONICAL DNA AND RNA STRUCTURES, PARTICULARLY G4, IM AND TRIPLEXES, MAY INVOLVE MICRORNAS AS WELL AS ION AND PROTON FLUXES. WE ARE PROPOSING EXPERIMENTS IN ACUTE BRAIN SLICES AND IN VIVO TO TEST OUR HYPOTHESIS. THE PROPOSED STUDIES WOULD PROVIDE NEW INSIGHTS INTO FUNDAMENTAL NEURONAL MECHANISMS IN HEALTH AND DISEASE AND POTENTIALLY OPEN NEW AVENUES FOR TREATING MENTAL HEALTH DISORDERS. 2019 8 669 28 BONE MARROW STROMAL CELL ANTIGEN-1 (CD157) REGULATED BY SPHINGOSINE KINASE 2 MEDIATES KIDNEY FIBROSIS. CHRONIC KIDNEY DISEASE IS A PROGRESSIVE DISEASE THAT MAY LEAD TO END-STAGE RENAL DISEASE. INTERSTITIAL FIBROSIS DEVELOPS AS THE DISEASE PROGRESSES. THERAPIES THAT FOCUS ON FIBROSIS TO DELAY OR REVERSE PROGRESSIVE RENAL FAILURE ARE LIMITED. WE AND OTHERS SHOWED THAT SPHINGOSINE KINASE 2-DEFICIENT MICE (SPHK2 (-/-)) DEVELOP LESS FIBROSIS IN MOUSE MODELS OF KIDNEY FIBROSIS. SPHINGOSINE KINASE2 (SPHK2), ONE OF TWO SPHINGOSINE KINASES THAT PRODUCE SPHINGOSINE 1-PHOSPHATE (S1P), IS PRIMARILY LOCATED IN THE NUCLEUS. S1P PRODUCED BY SPHK2 INHIBITS HISTONE DEACETYLASE (HDAC) AND CHANGES HISTONE ACETYLATION STATUS, WHICH CAN LEAD TO ALTERED TARGET GENE EXPRESSION. WE HYPOTHESIZED THAT SPHK2 EPIGENETICALLY REGULATES DOWNSTREAM GENES TO INDUCE FIBROSIS, AND WE PERFORMED A COMPREHENSIVE ANALYSIS USING THE COMBINATION OF RNA-SEQ AND CHIP-SEQ. BST1/CD157 WAS IDENTIFIED AS A GENE THAT IS REGULATED BY SPHK2 THROUGH A CHANGE IN HISTONE ACETYLATION LEVEL, AND BST1 (-/-) MICE WERE FOUND TO DEVELOP LESS RENAL FIBROSIS AFTER UNILATERAL ISCHEMIA-REPERFUSION INJURY, A MOUSE MODEL OF KIDNEY FIBROSIS. ALTHOUGH BST1 IS A CELL-SURFACE MOLECULE THAT HAS A WIDE VARIETY OF FUNCTIONS THROUGH ITS VARIED ENZYMATIC ACTIVITIES AND DOWNSTREAM INTRACELLULAR SIGNALING PATHWAYS, NO STUDIES ON THE ROLE OF BST1 IN KIDNEY DISEASES HAVE BEEN REPORTED PREVIOUSLY. IN THE CURRENT STUDY, WE DEMONSTRATED THAT BST1 IS A GENE THAT IS REGULATED BY SPHK2 THROUGH EPIGENETIC CHANGE AND IS CRITICAL IN KIDNEY FIBROSIS. 2022 9 5636 28 SERELAXIN ALLEVIATES CARDIAC FIBROSIS THROUGH INHIBITING ENDOTHELIAL-TO-MESENCHYMAL TRANSITION VIA RXFP1. RATIONALE: CARDIAC FIBROSIS IS AN INTEGRAL CONSTITUENT OF EVERY FORM OF CHRONIC HEART DISEASE, AND PERSISTENCE OF FIBROSIS REDUCES TISSUE COMPLIANCE AND ACCELERATES THE PROGRESSION TO HEART FAILURE. RELAXIN-2 IS A HUMAN HORMONE, WHICH HAS VARIOUS PHYSIOLOGICAL FUNCTIONS SUCH AS MEDIATING RENAL VASODILATION IN PREGNANCY. ITS RECOMBINANT FORM SERELAXIN HAS RECENTLY BEEN TESTED IN CLINICAL TRIALS AS A THERAPY FOR ACUTE HEART FAILURE BUT DID NOT MEET ITS PRIMARY ENDPOINTS. THE AIM OF THIS STUDY IS TO EXAMINE WHETHER SERELAXIN HAS AN ANTI-FIBROTIC EFFECT IN THE HEART AND THEREFORE COULD BE BENEFICIAL IN CHRONIC HEART FAILURE. METHODS: WE UTILIZED TWO DIFFERENT CARDIAC FIBROSIS MOUSE MODELS (ASCENDING AORTIC CONSTRICTION (AAC) AND ANGIOTENSIN II (ATII) ADMINISTRATION VIA OSMOTIC MINIPUMPS) TO ASSESS THE ANTI-FIBROTIC POTENTIAL OF SERELAXIN. HISTOLOGICAL ANALYSIS, IMMUNOFLUORESCENCE STAINING AND MOLECULAR ANALYSIS WERE PERFORMED TO ASSESS THE FIBROSIS LEVEL AND INDICATE ENDOTHELIAL CELLS WHICH ARE UNDERGOING ENDMT. IN VITRO TGFBETA1-INDUCED ENDOTHELIAL-TO-MESENCHYMAL TRANSITION (ENDMT) ASSAYS WERE PERFORMED IN HUMAN CORONARY ARTERY ENDOTHELIAL CELLS AND MOUSE CARDIAC ENDOTHELIAL CELLS (MCECS) AND WERE EXAMINED USING MOLECULAR METHODS. CHROMATIN IMMUNOPRECIPITATION-QPCR ASSAY WAS UTILIZED TO IDENTIFY THE SERELAXIN EFFECT ON CHROMATIN REMODELING IN THE RXFP1 PROMOTER REGION IN MCECS. RESULTS: OUR RESULTS DEMONSTRATE A SIGNIFICANT AND DOSE-DEPENDENT ANTI-FIBROTIC EFFECT OF SERELAXIN IN THE HEART IN BOTH MODELS. WE FURTHER SHOW THAT SERELAXIN MEDIATES THIS EFFECT, AT LEAST IN PART, THROUGH INHIBITION OF ENDMT THROUGH THE ENDOTHELIAL RELAXIN FAMILY PEPTIDE RECEPTOR 1 (RXFP1). WE FURTHER DEMONSTRATE THAT SERELAXIN ADMINISTRATION IS ABLE TO INCREASE ITS OWN RECEPTOR EXPRESSION (RXFP1) THROUGH EPIGENETIC REGULATION IN FORM OF HISTONE MODIFICATIONS BY ATTENUATING TGFBETA-PSMAD2/3 SIGNALING IN ENDOTHELIAL CELLS. CONCLUSIONS: THIS STUDY IS THE FIRST TO IDENTIFY THAT SERELAXIN INCREASES THE EXPRESSION OF ITS OWN RECEPTOR RXFP1 AND THAT THIS MEDIATES THE INHIBITION OF ENDMT AND CARDIAC FIBROSIS, SUGGESTING THAT SERELAXIN MAY HAVE A BENEFICIAL EFFECT AS ANTI-FIBROTIC THERAPY IN CHRONIC HEART FAILURE. 2020 10 5503 23 RGS9-2--CONTROLLED ADAPTATIONS IN THE STRIATUM DETERMINE THE ONSET OF ACTION AND EFFICACY OF ANTIDEPRESSANTS IN NEUROPATHIC PAIN STATES. THE STRIATAL PROTEIN REGULATOR OF G-PROTEIN SIGNALING 9-2 (RGS9-2) PLAYS A KEY MODULATORY ROLE IN OPIOID, MONOAMINE, AND OTHER G-PROTEIN-COUPLED RECEPTOR RESPONSES. HERE, WE USE THE MURINE SPARED-NERVE INJURY MODEL OF NEUROPATHIC PAIN TO INVESTIGATE THE MECHANISM BY WHICH RGS9-2 IN THE NUCLEUS ACCUMBENS (NAC), A BRAIN REGION INVOLVED IN MOOD, REWARD, AND MOTIVATION, MODULATES THE ACTIONS OF TRICYCLIC ANTIDEPRESSANTS (TCAS). PREVENTION OF RGS9-2 ACTION IN THE NAC INCREASES THE EFFICACY OF THE TCA DESIPRAMINE AND DRAMATICALLY ACCELERATES ITS ONSET OF ACTION. BY CONTROLLING THE ACTIVATION OF EFFECTOR MOLECULES BY G PROTEIN ALPHA AND BETAGAMMA SUBUNITS, RGS9-2 AFFECTS SEVERAL PROTEIN INTERACTIONS, PHOSPHOPROTEIN LEVELS, AND THE FUNCTION OF THE EPIGENETIC MODIFIER HISTONE DEACETYLASE 5, WHICH ARE IMPORTANT FOR TCA RESPONSIVENESS. FURTHERMORE, INFORMATION FROM RNA-SEQUENCING ANALYSIS REVEALS THAT RGS9-2 IN THE NAC AFFECTS THE EXPRESSION OF MANY GENES KNOWN TO BE INVOLVED IN NOCICEPTION, ANALGESIA, AND ANTIDEPRESSANT DRUG ACTIONS. OUR FINDINGS PROVIDE NOVEL INFORMATION ON NAC-SPECIFIC CELLULAR MECHANISMS THAT MEDIATE THE ACTIONS OF TCAS IN NEUROPATHIC PAIN STATES. 2015 11 5009 25 PERK IS A CRITICAL METABOLIC HUB FOR IMMUNOSUPPRESSIVE FUNCTION IN MACROPHAGES. CHRONIC INFLAMMATION TRIGGERS COMPENSATORY IMMUNOSUPPRESSION TO STOP INFLAMMATION AND MINIMIZE TISSUE DAMAGE. STUDIES HAVE DEMONSTRATED THAT ENDOPLASMIC RETICULUM (ER) STRESS AUGMENTS THE SUPPRESSIVE PHENOTYPES OF IMMUNE CELLS; HOWEVER, THE MOLECULAR MECHANISMS UNDERPINNING THIS PROCESS AND HOW IT LINKS TO THE METABOLIC REPROGRAMMING OF IMMUNOSUPPRESSIVE MACROPHAGES REMAIN ELUSIVE. IN THE PRESENT STUDY, WE REPORT THAT THE HELPER T CELL 2 CYTOKINE INTERLEUKIN-4 AND THE TUMOR MICROENVIRONMENT INCREASE THE ACTIVITY OF A PROTEIN KINASE RNA-LIKE ER KINASE (PERK)-SIGNALING CASCADE IN MACROPHAGES AND PROMOTE IMMUNOSUPPRESSIVE M2 ACTIVATION AND PROLIFERATION. LOSS OF PERK SIGNALING IMPEDED MITOCHONDRIAL RESPIRATION AND LIPID OXIDATION CRITICAL FOR M2 MACROPHAGES. PERK ACTIVATION MEDIATED THE UPREGULATION OF PHOSPHOSERINE AMINOTRANSFERASE 1 (PSAT1) AND SERINE BIOSYNTHESIS VIA THE DOWNSTREAM TRANSCRIPTION FACTOR ATF-4. INCREASED SERINE BIOSYNTHESIS RESULTED IN ENHANCED MITOCHONDRIAL FUNCTION AND ALPHA-KETOGLUTARATE PRODUCTION REQUIRED FOR JMJD3-DEPENDENT EPIGENETIC MODIFICATION. INHIBITION OF PERK SUPPRESSED MACROPHAGE IMMUNOSUPPRESSIVE ACTIVITY AND COULD ENHANCE THE EFFICACY OF IMMUNE CHECKPOINT PROGRAMMED CELL DEATH PROTEIN 1 INHIBITION IN MELANOMA. OUR FINDINGS DELINEATE A PREVIOUSLY UNDESCRIBED CONNECTION BETWEEN PERK SIGNALING AND PSAT1-MEDIATED SERINE METABOLISM CRITICAL FOR PROMOTING IMMUNOSUPPRESSIVE FUNCTION IN M2 MACROPHAGES. 2022 12 3049 24 GENOME-WIDE ANALYSIS REVEALS ZINC TRANSPORTER ZIP9 REGULATED BY DNA METHYLATION PROMOTES RADIATION-INDUCED SKIN FIBROSIS VIA THE TGF-BETA SIGNALING PATHWAY. RADIATION-INDUCED SKIN FIBROSIS IS A DETRIMENTAL AND CHRONIC DISORDER THAT OCCURS AFTER RADIATION EXPOSURE. DNA METHYLATION HAS BEEN CHARACTERIZED AS AN IMPORTANT REGULATORY MECHANISM OF MULTIPLE PATHOLOGICAL PROCESSES. IN THIS STUDY, WE COMPARED THE GENOME-WIDE DNA METHYLATION STATUS IN RADIATION-INDUCED FIBROTIC SKIN AND ADJACENT NORMAL TISSUES OF RATS BY METHYLATED DNA IMMUNOPRECIPITATION SEQUENCING. RADIATION-INDUCED FIBROTIC SKIN SHOWED DIFFERENTIALLY METHYLATED REGIONS ASSOCIATED WITH 3,650 PROTEIN-CODING GENES, 72 MICRORNAS, 5,836 LONG NONCODING RNAS AND 3 PIWI-INTERACTING RNAS. BY INTEGRATING THE MRNA AND METHYLATION PROFILES, THE ZINC TRANSPORTER SLC39A9/ZIP9 WAS INVESTIGATED IN GREATER DETAIL. THE PROTEIN LEVEL OF ZIP9 WAS INCREASED IN IRRADIATED SKIN TISSUES OF HUMANS, MONKEYS, AND RATS, ESPECIALLY IN RADIOGENIC FIBROTIC SKIN TISSUES. RADIATION INDUCED THE DEMETHYLATION OF A CPG DINUCLEOTIDE IN EXON 1 OF ZIP9 THAT RESULTED IN RECRUITMENT OF THE TRANSCRIPTIONAL FACTOR SP1 AND INCREASED ZIP9 EXPRESSION. OVEREXPRESSION OF ZIP9 RESULTED IN ACTIVATION OF THE PROFIBROTIC TRANSFORMING GROWTH FACTOR-BETA SIGNALING PATHWAY THROUGH PROTEIN KINASE B IN HUMAN FIBROBLASTS. IN ADDITION, RADIATION-INDUCED SKIN FIBROSIS WAS ASSOCIATED WITH INCREASED ZINC ACCUMULATION. THE ZINC CHELATOR N,N,N',N'-TETRAKIS(2-PYRIDYLMETHYL)-1,2-ETHYLENEDIAMINE ABROGATED ZIP9-INDUCED ACTIVATION OF THE TRANSFORMING GROWTH FACTOR-BETA SIGNALING PATHWAY AND ATTENUATED RADIATION-INDUCED SKIN FIBROSIS IN A RAT MODEL. IN SUMMARY, OUR FINDINGS ILLUSTRATE EPIGENETIC REGULATION OF ZIP9 AND ITS CRITICAL ROLE IN PROMOTING RADIATION-INDUCED SKIN FIBROSIS. 2020 13 5433 15 REL/NF-KAPPA B/I KAPPA B SIGNAL TRANSDUCTION IN THE GENERATION AND TREATMENT OF HUMAN CANCER. THE REL/NF-KAPPA B FAMILY IS A GROUP OF STRUCTURALLY-RELATED, TIGHTLY-REGULATED TRANSCRIPTION FACTORS THAT CONTROL THE EXPRESSION OF A MULTITUDE OF GENES INVOLVED IN KEY CELLULAR AND ORGANISMAL PROCESSES. THE REL/NF-KAPPA B SIGNAL TRANSDUCTION PATHWAY IS MISREGULATED IN A VARIETY OF HUMAN CANCERS, ESPECIALLY ONES OF LYMPHOID CELL ORIGIN, DUE EITHER TO GENETIC CHANGES (SUCH AS CHROMOSOMAL REARRANGEMENTS, AMPLIFICATIONS, AND MUTATIONS) OR TO CHRONIC ACTIVATION OF THE PATHWAY BY EPIGENETIC MECHANISMS. CONSTITUTIVE ACTIVATION OF THE REL/NF-KAPPA B PATHWAY CAN CONTRIBUTE TO THE ONCOGENIC STATE IN SEVERAL WAYS, FOR EXAMPLE, BY DRIVING PROLIFERATION, BY ENHANCING CELL SURVIVAL, OR BY PROMOTING ANGIOGENESIS OR METASTASIS. IN MANY CASES, INHIBITION OF REL/NF-KAPPA B ACTIVITY REVERSES ALL OR PART OF THE MALIGNANT STATE. THUS, THE REL/NF-KAPPA B PATHWAY HAS RECEIVED MUCH ATTENTION AS A FOCAL POINT FOR CLINICAL INTERVENTION. 2002 14 662 17 BLOOD MONOCYTE TRANSCRIPTOME AND EPIGENOME ANALYSES REVEAL LOCI ASSOCIATED WITH HUMAN ATHEROSCLEROSIS. LITTLE IS KNOWN REGARDING THE EPIGENETIC BASIS OF ATHEROSCLEROSIS. HERE WE PRESENT THE CD14+ BLOOD MONOCYTE TRANSCRIPTOME AND EPIGENOME SIGNATURES ASSOCIATED WITH HUMAN ATHEROSCLEROSIS. THE TRANSCRIPTOME SIGNATURE INCLUDES TRANSCRIPTION COACTIVATOR, ARID5B, WHICH IS KNOWN TO FORM A CHROMATIN DEREPRESSOR COMPLEX WITH A HISTONE H3K9ME2-SPECIFIC DEMETHYLASE AND PROMOTE ADIPOGENESIS AND SMOOTH MUSCLE DEVELOPMENT. ARID5B CPG (CG25953130) METHYLATION IS INVERSELY ASSOCIATED WITH BOTH ARID5B EXPRESSION AND ATHEROSCLEROSIS, CONSISTENT WITH THIS CPG RESIDING IN AN ARID5B ENHANCER REGION, BASED ON CHROMATIN CAPTURE AND HISTONE MARKS DATA. MEDIATION ANALYSIS SUPPORTS ASSUMPTIONS THAT ARID5B EXPRESSION MEDIATES EFFECTS OF CG25953130 METHYLATION AND SEVERAL CARDIOVASCULAR DISEASE RISK FACTORS ON ATHEROSCLEROTIC BURDEN. IN LIPOPOLYSACCHARIDE-STIMULATED HUMAN THP1 MONOCYTES, ARID5B KNOCKDOWN REDUCED EXPRESSION OF GENES INVOLVED IN ATHEROSCLEROSIS-RELATED INFLAMMATORY AND LIPID METABOLISM PATHWAYS, AND INHIBITED CELL MIGRATION AND PHAGOCYTOSIS. THESE DATA SUGGEST THAT ARID5B EXPRESSION, POSSIBLY REGULATED BY AN EPIGENETICALLY CONTROLLED ENHANCER, PROMOTES ATHEROSCLEROSIS BY DYSREGULATING IMMUNOMETABOLISM TOWARDS A CHRONIC INFLAMMATORY PHENOTYPE.THE MOLECULAR MECHANISMS MEDIATING THE IMPACT OF ENVIRONMENTAL FACTORS IN ATHEROSCLEROSIS ARE UNCLEAR. HERE, THE AUTHORS EXAMINE CD14+ BLOOD MONOCYTE'S TRANSCRIPTOME AND EPIGENOME SIGNATURES TO FIND DIFFERENTIAL METHYLATION AND EXPRESSION OF ARID5B TO BE ASSOCIATED WITH HUMAN ATHEROSCLEROSIS. 2017 15 2818 14 FIBROSIS UNDER ARREST. APPROXIMATELY 5% OF PEOPLE THAT ARE HOSPITALIZED FOR ANY REASON DEVELOP ACUTE KIDNEY FAILURE, WHICH, IN SOME CASES, PROGRESSES TO A CHRONIC CONDITION RESULTING IN FIBROSIS OF THE KIDNEY AND PERMANENT CHANGES IN THE ORGAN'S FUNCTION. TWO NEW STUDIES SUGGEST THAT CELL CYCLE ARREST OF EPITHELIAL CELLS AND EPIGENETIC MODIFICATIONS HAVE KEY ROLES IN THE SWITCH TO CHRONIC DISEASE (PAGES 535-543 AND 544-550). 2010 16 370 24 AN APICOMPLEXAN BROMODOMAIN PROTEIN, TGBDP1, ASSOCIATES WITH DIVERSE EPIGENETIC FACTORS TO REGULATE ESSENTIAL TRANSCRIPTIONAL PROCESSES IN TOXOPLASMA GONDII. THE PROTOZOAN PATHOGEN TOXOPLASMA GONDII RELIES ON TIGHT REGULATION OF GENE EXPRESSION TO INVADE AND ESTABLISH INFECTION IN ITS HOST. THE DIVERGENT GENE REGULATORY MECHANISMS OF TOXOPLASMA AND RELATED APICOMPLEXAN PATHOGENS RELY HEAVILY ON REGULATORS OF CHROMATIN STRUCTURE AND HISTONE MODIFICATIONS. THE IMPORTANT CONTRIBUTION OF HISTONE ACETYLATION FOR TOXOPLASMA IN BOTH ACUTE AND CHRONIC INFECTION HAS BEEN DEMONSTRATED, WHERE HISTONE ACETYLATION INCREASES AT ACTIVE GENE LOCI. HOWEVER, THE DIRECT CONSEQUENCES OF SPECIFIC HISTONE ACETYLATION MARKS AND THE CHROMATIN PATHWAY THAT INFLUENCES TRANSCRIPTIONAL REGULATION IN RESPONSE TO THE MODIFICATION ARE UNCLEAR. AS A READER OF LYSINE ACETYLATION, THE BROMODOMAIN SERVES AS A MEDIATOR BETWEEN THE ACETYLATED HISTONE AND TRANSCRIPTIONAL REGULATORS. HERE WE SHOW THAT THE BROMODOMAIN PROTEIN, TGBDP1, WHICH IS CONSERVED AMONG APICOMPLEXA AND WITHIN THE ALVEOLATA SUPERPHYLUM, IS ESSENTIAL FOR TOXOPLASMA ASEXUAL PROLIFERATION. USING CLEAVAGE UNDER TARGETS AND TAGMENTATION, WE DEMONSTRATE THAT TGBDP1 IS RECRUITED TO TRANSCRIPTIONAL START SITES OF A LARGE PROPORTION OF PARASITE GENES. TRANSCRIPTIONAL PROFILING DURING TGBDP1 KNOCKDOWN REVEALED THAT LOSS OF TGBDP1 LEADS TO MAJOR DYSREGULATION OF GENE EXPRESSION, IMPLYING MULTIPLE ROLES FOR TGBDP1 IN BOTH GENE ACTIVATION AND REPRESSION. THIS IS SUPPORTED BY INTERACTOME ANALYSIS OF TGBDP1 DEMONSTRATING THAT TGBDP1 FORMS A CORE COMPLEX WITH TWO OTHER BROMODOMAIN PROTEINS AND AN APIAP2 FACTOR. THIS CORE COMPLEX APPEARS TO INTERACT WITH OTHER EPIGENETIC FACTORS SUCH AS NUCLEOSOME REMODELING COMPLEXES. WE CONCLUDE THAT TGBDP1 INTERACTS WITH DIVERSE EPIGENETIC REGULATORS TO EXERT OPPOSING INFLUENCES ON GENE EXPRESSION IN THE TOXOPLASMA TACHYZOITE. IMPORTANCE HISTONE ACETYLATION IS CRITICAL FOR PROPER REGULATION OF GENE EXPRESSION IN THE SINGLE-CELLED EUKARYOTIC PATHOGEN TOXOPLASMA GONDII. BROMODOMAIN PROTEINS ARE "READERS" OF HISTONE ACETYLATION AND MAY LINK THE MODIFIED CHROMATIN TO TRANSCRIPTION FACTORS. HERE, WE SHOW THAT THE BROMODOMAIN PROTEIN TGBDP1 IS ESSENTIAL FOR PARASITE SURVIVAL AND THAT LOSS OF TGBDP1 RESULTS IN GLOBAL DYSREGULATION OF GENE EXPRESSION. TGBDP1 IS RECRUITED TO THE PROMOTER REGION OF A LARGE PROPORTION OF PARASITE GENES, FORMS A CORE COMPLEX WITH TWO OTHER BROMODOMAIN PROTEINS, AND INTERACTS WITH DIFFERENT TRANSCRIPTIONAL REGULATORY COMPLEXES. WE CONCLUDE THAT TGBDP1 IS A KEY FACTOR FOR SENSING SPECIFIC HISTONE MODIFICATIONS TO INFLUENCE MULTIPLE FACETS OF TRANSCRIPTIONAL REGULATION IN TOXOPLASMA GONDII. 2023 17 3962 26 LONG NONCODING RNA LEENE PROMOTES ANGIOGENESIS AND ISCHEMIC RECOVERY IN DIABETES MODELS. IMPAIRED ANGIOGENESIS IN DIABETES IS A KEY PROCESS CONTRIBUTING TO ISCHEMIC DISEASES SUCH AS PERIPHERAL ARTERIAL DISEASE. EPIGENETIC MECHANISMS, INCLUDING THOSE MEDIATED BY LONG NONCODING RNAS (LNCRNAS), ARE CRUCIAL LINKS CONNECTING DIABETES AND THE RELATED CHRONIC TISSUE ISCHEMIA. HERE WE IDENTIFY THE LNCRNA THAT ENHANCES ENDOTHELIAL NITRIC OXIDE SYNTHASE (ENOS) EXPRESSION (LEENE) AS A REGULATOR OF ANGIOGENESIS AND ISCHEMIC RESPONSE. LEENE EXPRESSION WAS DECREASED IN DIABETIC CONDITIONS IN CULTURED ENDOTHELIAL CELLS (ECS), MOUSE HIND LIMB MUSCLES, AND HUMAN ARTERIES. INHIBITION OF LEENE IN HUMAN MICROVASCULAR ECS REDUCED THEIR ANGIOGENIC CAPACITY WITH A DYSREGULATED ANGIOGENIC GENE PROGRAM. DIABETIC MICE DEFICIENT IN LEENE DEMONSTRATED IMPAIRED ANGIOGENESIS AND PERFUSION FOLLOWING HIND LIMB ISCHEMIA. IMPORTANTLY, OVEREXPRESSION OF HUMAN LEENE RESCUED THE IMPAIRED ISCHEMIC RESPONSE IN LEENE-KNOCKOUT MICE AT TISSUE FUNCTIONAL AND SINGLE-CELL TRANSCRIPTOMIC LEVELS. MECHANISTICALLY, LEENE RNA PROMOTED TRANSCRIPTION OF PROANGIOGENIC GENES IN ECS, SUCH AS KDR (ENCODING VEGFR2) AND NOS3 (ENCODING ENOS), POTENTIALLY BY INTERACTING WITH LEO1, A KEY COMPONENT OF THE RNA POLYMERASE II-ASSOCIATED FACTOR COMPLEX AND MYC, A CRUCIAL TRANSCRIPTION FACTOR FOR ANGIOGENESIS. TAKEN TOGETHER, OUR FINDINGS DEMONSTRATE AN ESSENTIAL ROLE FOR LEENE IN THE REGULATION OF ANGIOGENESIS AND TISSUE PERFUSION. FUNCTIONAL ENHANCEMENT OF LEENE TO RESTORE ANGIOGENESIS FOR TISSUE REPAIR AND REGENERATION MAY REPRESENT A POTENTIAL STRATEGY TO TACKLE ISCHEMIC VASCULAR DISEASES. 2023 18 3002 15 GENETIC, EPIGENETIC AND POSTTRANSCRIPTIONAL MECHANISMS FOR TREATMENT OF MAJOR DEPRESSION: THE 5-HT1A RECEPTOR GENE AS A PARADIGM. MAJOR DEPRESSION AND ANXIETY ARE HIGHLY PREVALENT AND INVOLVE CHRONIC DYSREGULATION OF SEROTONIN, BUT THEY REMAIN POORLY UNDERSTOOD. HERE, WE REVIEW NOVEL TRANSCRIPTIONAL (GENETIC, EPIGENETIC) AND POSTTRANSCRIPTIONAL (MICRORNA, ALTERNATIVE SPLICING) MECHANISMS IMPLICATED IN MENTAL ILLNESS, FOCUSING ON A KEY SEROTONIN-RELATED REGULATOR, THE SEROTONIN 1A (5-HT1A) RECEPTOR. FUNCTIONAL SINGLE-NUCLEOTIDE POLYMORPHISMS AND STRESS-INDUCED DNA METHYLATION OF THE 5-HT1A PROMOTER CONVERGE TO DIFFERENTIALLY ALTER PRE- AND POSTSYNAPTIC 5-HT1A RECEPTOR EXPRESSION ASSOCIATED WITH MAJOR DEPRESSION AND REDUCED THERAPEUTIC RESPONSE TO SEROTONERGIC ANTIDEPRESSANTS. MAJOR DEPRESSION IS ALSO ASSOCIATED WITH ALTERED LEVELS OF SPLICE FACTORS AND MICRORNA, POSTTRANSCRIPTIONAL MECHANISMS THAT REGULATE RNA STABILITY. THE HUMAN 5-HT1A 3'-UNTRANSLATED REGION IS ALTERNATIVELY SPLICED, REMOVING MICRORNA SITES AND INCREASING 5-HT1A EXPRESSION, WHICH IS REDUCED IN MAJOR DEPRESSION AND MAY BE GENOTYPE-DEPENDENT. THUS, THE 5-HT1A RECEPTOR GENE ILLUSTRATES THE CONVERGENCE OF GENETIC, EPIGENETIC AND POSTTRANSCRIPTIONAL MECHANISMS IN GENE EXPRESSION, NEURODEVELOPMENT AND NEUROPLASTICITY, AND MAJOR DEPRESSION. UNDERSTANDING GENE REGULATORY MECHANISMS COULD ENHANCE THE DETECTION, CATEGORIZATION AND PERSONALIZED TREATMENT OF MAJOR DEPRESSION. 2019 19 5449 20 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 20 6690 19 VALPROIC ACID SILENCING OF ASCL1B/ASCL1 RESULTS IN THE FAILURE OF SEROTONERGIC DIFFERENTIATION IN A ZEBRAFISH MODEL OF FETAL VALPROATE SYNDROME. FETAL VALPROATE SYNDROME (FVS) IS CAUSED BY IN UTERO EXPOSURE TO THE DRUG SODIUM VALPROATE. VALPROATE IS USED WORLDWIDE FOR THE TREATMENT OF EPILEPSY, AS A MOOD STABILISER AND FOR ITS PAIN-RELIEVING PROPERTIES. IN ADDITION TO BIRTH DEFECTS, FVS IS ASSOCIATED WITH AN INCREASED RISK OF AUTISM SPECTRUM DISORDER (ASD), WHICH IS CHARACTERISED BY ABNORMAL BEHAVIOURS. VALPROATE PERTURBS MULTIPLE BIOCHEMICAL PATHWAYS AND ALTERS GENE EXPRESSION THROUGH ITS INHIBITION OF HISTONE DEACETYLASES. WHICH, IF ANY, OF THESE MECHANISMS IS RELEVANT TO THE GENESIS OF ITS BEHAVIOURAL SIDE EFFECTS IS UNCLEAR. NEUROANATOMICAL CHANGES ASSOCIATED WITH FVS HAVE BEEN REPORTED AND, AMONG THESE, ALTERED SEROTONERGIC NEURONAL DIFFERENTIATION IS A CONSISTENT FINDING. ALTERED SEROTONIN HOMEOSTASIS IS ALSO ASSOCIATED WITH AUTISM. HERE WE HAVE USED A CHEMICAL-GENETICS APPROACH TO INVESTIGATE THE UNDERLYING MOLECULAR DEFECT IN A ZEBRAFISH FVS MODEL. VALPROATE CAUSES THE SELECTIVE FAILURE OF ZEBRAFISH CENTRAL SEROTONIN EXPRESSION. IT DOES SO BY DOWNREGULATING THE PRONEURAL GENE ASCL1B, AN ORTHOLOG OF MAMMALIAN ASCL1, WHICH IS A KNOWN DETERMINANT OF SEROTONERGIC IDENTITY IN THE MAMMALIAN BRAINSTEM. ASCL1B IS SUFFICIENT TO RESCUE SEROTONIN EXPRESSION IN VALPROATE-TREATED EMBRYOS. CHEMICAL AND GENETIC BLOCKADE OF THE HISTONE DEACETYLASE HDAC1 DOWNREGULATES ASCL1B, CONSISTENT WITH THE HDAC1-MEDIATED SILENCING OF ASCL1B EXPRESSION BY VALPROATE. MOREOVER, TONIC NOTCH SIGNALLING IS CRUCIAL FOR ASCL1B REPRESSION BY VALPROATE. CONCOMITANT BLOCKADE OF NOTCH SIGNALLING RESTORES ASCL1B EXPRESSION AND SEROTONIN EXPRESSION IN BOTH VALPROATE-EXPOSED AND HDAC1 MUTANT EMBRYOS. TOGETHER, THESE DATA PROVIDE A MOLECULAR EXPLANATION FOR SEROTONERGIC DEFECTS IN FVS AND HIGHLIGHT AN EPIGENETIC MECHANISM FOR GENOME-ENVIRONMENT INTERACTION IN DISEASE. 2014