1 3088 135 GENOMEWIDE HISTONE H3 LYSINE 9 ACETYLATION PROFILING IN CD4+ T CELLS REVEALED ENDOPLASMIC RETICULUM STRESS DEFICIENCY IN PATIENTS WITH ACUTE-ON-CHRONIC LIVER FAILURE. ACUTE-ON-CHRONIC LIVER FAILURE (ACLF) DISPLAYED 'SEPSIS-LIKE' IMMUNE PARALYSIS. LITTLE IS KNOWN ABOUT THE ROLE OF CD4+ T LYMPHOCYTES, THE PRIMARY REGULATOR OF INNATE AND ADOPTED IMMUNE SYSTEM, PLAYED IN ACLF. ACETYLATION OF HISTONE H3 LYSINE 9 (H3K9AC), A KEY EPIGENETIC MODIFICATION, TIGHTLY CONTROLS GENE TRANSCRIPTION. WHETHER AND HOW DOES H3K9AC MODIFICATION REGULATE CD4+ T CELLS IN ACLF REMAINS UNCLEAR. PBMCS WERE ISOLATED FROM PATIENTS WITH ACLF, IMMUNE TOLERANCE OF CHRONIC HEPATITIS B (CHB-T) AND IMMUNE ACTIVE OF CHRONIC HEPATITIS B (CHB-A). THEN, CD4+ T LYMPHOCYTES WERE PURIFIED BY MAGNETIC MICROBEADS, AND THE PURITY WAS CONFIRMED BY FLOW CYTOMETRY. H3K9AC VARIATIONS WERE ANALYSED IN CD4+ T CELLS USING CHROMATIN IMMUNOPRECIPITATION MICROARRAY AND THEN CONFIRMED BY QUANTITATIVE PCR. WHOLE-GENOME H3K9 ACETYLATION ANALYSES WERE CONDUCTED BY BIOINFORMATICS. A TOTAL OF 70 GENES WERE DIFFERENTLY MODIFIED IN H3K9AC BETWEEN CHB-A AND ACLF GROUPS, WHILE 44 GENES WERE DIFFERENTLY MODIFIED IN H3K9AC BETWEEN CHB-T AND ACLF GROUPS. CLUSTERING ALGORITHM ANALYSIS SHOWED PATIENTS WITH ACLF DISPLAYED 'SEPSIS-LIKE' IMMUNE PARALYSIS. FUNCTIONAL ANALYSIS SHOWED ENDOPLASMIC RETICULUM (ER) STRESS, OR DOWNSTREAM PATHWAY-RELATED GENES, SUCH AS BIP, ATF4, PER1, CSNK1D, IRF3, BNIP1, AKT1 AND UBC, WERE DIFFERENTIALLY MODIFIED IN ACLF. WE PROFILED H3K9 ACETYL MODIFICATION IN CD4+ T LYMPHOCYTES FROM HBV-INFECTED PATIENTS WITH THREE DIFFERENT IMMUNE STATES, THAT IS ACLF, IMMUNE TOLERANCE AND IMMUNE ACTIVE PHASES. ACLF DISPLAYED 'SEPSIS-LIKE' IMMUNE PARALYSIS. ER STRESS IN CD4+ T LYMPHOCYTES ATTRIBUTED TO ACLF. THIS STUDY PROVIDES SOME USEFUL CLUES FOR REVEALING THE MECHANISMS UNDERLYING ACLF. 2015 2 2395 37 EPIGENETIC REPROGRAMMING IN MIST1(-/-) MICE PREDICTS THE MOLECULAR RESPONSE TO CERULEIN-INDUCED PANCREATITIS. GENE EXPRESSION IS AFFECTED BY MODIFICATIONS TO HISTONE CORE PROTEINS WITHIN CHROMATIN. CHANGES IN THESE MODIFICATIONS, OR EPIGENETIC REPROGRAMMING, CAN DICTATE CELL FATE AND PROMOTE SUSCEPTIBILITY TO DISEASE. THE GOAL OF THIS STUDY WAS TO DETERMINE THE EXTENT OF EPIGENETIC REPROGRAMMING IN RESPONSE TO CHRONIC STRESS THAT OCCURS FOLLOWING ABLATION OF MIST1 (MIST1(-/-) ), WHICH IS REPRESSED IN PANCREATIC DISEASE. CHROMATIN IMMUNOPRECIPITATION FOR TRIMETHYLATION OF LYSINE RESIDUE 4 ON HISTONE 3 (H3K4ME3) IN PURIFIED ACINAR CELLS FROM WILD TYPE AND MIST1(-/-) MICE WAS FOLLOWED BY NEXT GENERATION SEQUENCING (CHIP-SEQ) OR CHIP-QPCR. H3K4ME3-ENRICHED GENES WERE ASSESSED FOR EXPRESSION BY QRT-PCR IN PANCREATIC TISSUE BEFORE AND AFTER INDUCTION OF CERULEIN-INDUCED PANCREATITIS. WHILE MOST OF H3K4ME3-ENRICHMENT IS RESTRICTED TO TRANSCRIPTIONAL START SITES, >25% OF ENRICHMENT SITES ARE FOUND WITHIN, DOWNSTREAM OR BETWEEN ANNOTATED GENES. LESS THAN 10% OF THESE SITES WERE ALTERED IN MIST1(-/-) ACINI, WITH MOST CHANGES IN H3K4ME3 ENRICHMENT NOT REFLECTING ALTERED GENE EXPRESSION. INGENUITY PATHWAY ANALYSIS OF GENES DIFFERENTIALLY-ENRICHED FOR H3K4ME3 REVEALED AN ASSOCIATION WITH PANCREATITIS AND PANCREATIC DUCTAL ADENOCARCINOMA IN MIST1(-/-) TISSUE. MOST OF THESE GENES WERE NOT DIFFERENTIALLY EXPRESSED BUT SEVERAL WERE READILY INDUCED BY ACUTE EXPERIMENTAL PANCREATITIS, WITH SIGNIFICANTLY INCREASED EXPRESSION IN MIST1(-/-) TISSUE RELATIVE TO WILD TYPE MICE. WE SUGGEST THAT THE CHRONIC CELL STRESS OBSERVED IN THE ABSENCE OF MIST1 RESULTS IN EPIGENETIC REPROGRAMMING OF GENES INVOLVED IN PROMOTING PANCREATITIS TO A POISED STATE, THEREBY INCREASING THE SENSITIVITY TO EVENTS THAT PROMOTE DISEASE. 2014 3 2200 35 EPIGENETIC MODIFICATION OF FOXP3 IN PATIENTS WITH CHRONIC HIV INFECTION. OBJECTIVES: HIV-1 MODULATES HOST CELL EPIGENETIC MACHINERY TO CONTROL ITS OWN REPLICATION AND INDUCE IMMUNE SUPPRESSION. HIV-1 INFECTION LEADS TO ACTIVATION OF T REGULATORY CELL (T(REG)), BUT THE MECHANISM UNDERLYING THIS IMMUNE MODULATION IS UNCLEAR. T(REG) PLAYS A PROMINENT ROLE IN GUT-MUCOSAL IMMUNE TOLERANCE BY RESTRAINING EXCESSIVE EFFECTOR T-CELL RESPONSES, A MECHANISM THAT IS KNOWN TO BE DISTURBED IN CHRONIC HIV-1 INFECTION. DNA METHYLATION PLAYS A MAJOR ROLE IN T(REG) LINEAGE COMMITMENT AND IMMUNE HOMEOSTASIS, WHICH MAY BE REGULATED BY HIV. TO INVESTIGATE THE MECHANISMS OF ABERRANT METHYLATION OF THE T(REG) MARKER FOXP3 IN HIV-1 INFECTION, WE EVALUATED THE EXPRESSION PATTERN OF METHYLATION-RELATED ENZYMES AND ITS CORRELATION TO FOXP3 METHYLATION. METHODS: FOXP3 PROMOTER METHYLATION IN THE COLON MUCOSA AND PERIPHERAL BLOOD FROM HIV-INFECTED PATIENTS AND CONTROL SUBJECTS WAS MEASURED USING PYROSEQUENCING. GENE EXPRESSION PATTERN OF DNA METHYLATION ENZYMES IN THE COLON MUCOSA WAS INVESTIGATED BY MICROARRAY AND QUANTITATIVE REVERSE TRANSCRIPTASE-POLYMERASE CHAIN REACTION ANALYSIS IN THE SAME SUBJECTS. RESULTS: FOXP3 PROMOTER WAS SIGNIFICANTLY (P