1 5716 120 SIRT6 PROTECTS VASCULAR SMOOTH MUSCLE CELLS FROM OSTEOGENIC TRANSDIFFERENTIATION VIA RUNX2 IN CHRONIC KIDNEY DISEASE. VASCULAR CALCIFICATION (VC) IS REGARDED AS AN IMPORTANT PATHOLOGICAL CHANGE LACKING EFFECTIVE TREATMENT AND ASSOCIATED WITH HIGH MORTALITY. SIRTUIN 6 (SIRT6) IS A MEMBER OF THE SIRTUIN FAMILY, A CLASS III HISTONE DEACETYLASE AND A KEY EPIGENETIC REGULATOR. SIRT6 HAS A PROTECTIVE ROLE IN PATIENTS WITH CHRONIC KIDNEY DISEASE (CKD). HOWEVER, THE EXACT ROLE AND MOLECULAR MECHANISM OF SIRT6 IN VC IN PATIENTS WITH CKD REMAIN UNCLEAR. HERE, WE DEMONSTRATED THAT SIRT6 WAS MARKEDLY DOWNREGULATED IN PERIPHERAL BLOOD MONONUCLEAR CELLS (PBMCS) AND IN THE RADIAL ARTERY TISSUE OF PATIENTS WITH CKD WITH VC. SIRT6-TRANSGENIC (SIRT6-TG) MICE SHOWED ALLEVIATED VC, WHILE VASCULAR SMOOTH MUSCLE CELL-SPECIFIC (VSMC-SPECIFIC) SIRT6 KNOCKED-DOWN MICE SHOWED SEVERE VC IN CKD. SIRT6 SUPPRESSED THE OSTEOGENIC TRANSDIFFERENTIATION OF VSMCS VIA REGULATION OF RUNT-RELATED TRANSCRIPTION FACTOR 2 (RUNX2). COIMMUNOPRECIPITATION (CO-IP) AND IMMUNOPRECIPITATION (IP) ASSAYS CONFIRMED THAT SIRT6 BOUND TO RUNX2. MOREOVER, RUNX2 WAS DEACETYLATED BY SIRT6 AND FURTHER PROMOTED NUCLEAR EXPORT VIA EXPORTIN 1 (XPO1), WHICH IN TURN CAUSED DEGRADATION OF RUNX2 THROUGH THE UBIQUITIN-PROTEASOME SYSTEM. THESE RESULTS DEMONSTRATED THAT SIRT6 PREVENTED VC BY SUPPRESSING THE OSTEOGENIC TRANSDIFFERENTIATION OF VSMCS, AND AS SUCH TARGETING SIRT6 MAY BE AN APPEALING THERAPEUTIC TARGET FOR VC IN CKD. 2022 2 6658 44 UPREGULATED LNCRNA H19 SPONGES MIR-106A-5P AND CONTRIBUTES TO ALDOSTERONE-INDUCED VASCULAR CALCIFICATION VIA ACTIVATING THE RUNX2-DEPENDENT PATHWAY. BACKGROUND: EXCESS ALDOSTERONE IS IMPLICATED IN VASCULAR CALCIFICATION (VC), BUT THE MECHANISM BY WHICH ALDOSTERONE-MR (MINERALOCORTICOID RECEPTOR) COMPLEX PROMOTES VC IS UNCLEAR. EMERGING EVIDENCE INDICATES THAT LONG-NONCODING RNA H19 (H19) PLAYS A CRITICAL ROLE IN VC. WE EXAMINED WHETHER ALDOSTERONE-INDUCED OSTEOGENIC DIFFERENTIATION OF VASCULAR SMOOTH MUSCLE CELLS (VSMCS) THROUGH H19 EPIGENETIC MODIFICATION OF RUNX2 (RUNT-RELATED TRANSCRIPTION FACTOR-2) IN A MR-DEPENDENT MANNER. METHODS: WE INDUCED IN VIVO RAT MODEL OF CHRONIC KIDNEY DISEASE USING A HIGH ADENINE AND PHOSPHATE DIET TO EXPLORE THE RELATIONSHIP AMONG ALDOSTERONE, MR, H19, AND VC. WE ALSO CULTURED HUMAN AORTIC VSMCS TO EXPLORE THE ROLES OF H19 IN ALDOSTERONE-MR COMPLEX-INDUCED OSTEOGENIC DIFFERENTIATION AND CALCIFICATION OF VSMCS. RESULTS: H19 AND RUNX2 WERE SIGNIFICANTLY INCREASED IN ALDOSTERONE-INDUCED VSMC OSTEOGENIC DIFFERENTIATION AND VC, BOTH IN VITRO AND IN VIVO, WHICH WERE SIGNIFICANTLY BLOCKED BY THE MR ANTAGONIST SPIRONOLACTONE. MECHANISTICALLY, OUR FINDINGS REVEAL THAT THE ALDOSTERONE-ACTIVATED MR BOUND TO H19 PROMOTER AND INCREASED ITS TRANSCRIPTIONAL ACTIVITY, AS DETERMINED BY CHROMATIN IMMUNOPRECIPITATION, ELECTROPHORETIC MOBILITY SHIFT ASSAY, AND LUCIFERASE REPORTER ASSAY. SILENCING H19 INCREASED MICRORNA-106A-5P (MIR-106A-5P) EXPRESSION, WHICH SUBSEQUENTLY INHIBITED ALDOSTERONE-INDUCED RUNX2 EXPRESSION AT THE POSTTRANSCRIPTIONAL LEVEL. IMPORTANTLY, WE OBSERVED A DIRECT INTERACTION BETWEEN H19 AND MIR-106A-5P, AND DOWNREGULATION OF MIR-106A-5P EFFICIENTLY REVERSED THE SUPPRESSION OF RUNX2 INDUCED BY H19 SILENCING. CONCLUSIONS: OUR STUDY CLARIFIES A NOVEL MECHANISM BY WHICH UPREGULATION OF H19 CONTRIBUTES TO ALDOSTERONE-MR COMPLEX-PROMOTED RUNX2-DEPENDENT VSMC OSTEOGENIC DIFFERENTIATION AND VC THROUGH SPONGING MIR-106A-5P. THESE FINDINGS HIGHLIGHT A POTENTIAL THERAPEUTIC TARGET FOR ALDOSTERONE-INDUCED VC. 2023 3 364 44 AMELIORATION OF UREMIC TOXIN INDOXYL SULFATE-INDUCED OSTEOBLASTIC CALCIFICATION BY SET DOMAIN CONTAINING LYSINE METHYLTRANSFERASE 7/9 PROTEIN. BACKGROUND: VASCULAR CALCIFICATION (VC) IS A VERY COMMON PHENOMENON IN PATIENTS WITH CHRONIC KIDNEY DISEASE (CKD). IT HAS BEEN REPORTED THAT SOME HISTONE METHYLATION PLAY A ROLE IN VC AS AN EPIGENETIC REGULATOR. INDOXYL SULFATE (IS) IS A PROTEIN-BOUND UREMIC TOXIN THAT HAS BEEN PROVEN AS ONE OF THE MAJOR RISK FACTORS OF CARDIOVASCULAR DISEASE IN CKD. SET DOMAIN CONTAINING LYSINE METHYLTRANSFERASE 7/9 (SET7/9) IS ONE OF THE IMPORTANT HISTONE METHYLTRANSFERASES. OBJECTIVES: THIS STUDY AIMED TO DETERMINE THE EFFECT OF IS ON THE EXPRESSION OF SET7/9 AND THE ROLE OF SET7/9 IN IS-INDUCED OSTEOBLASTIC DIFFERENTIATION AND CALCIFICATION OF VASCULAR SMOOTH MUSCLE CELLS (VSMCS). METHODS: VSMCS WERE INCUBATED WITH VARIOUS CONCENTRATIONS OF IS FOR DIFFERENT DURATIONS TO ASSESS OSTEOBLASTIC DIFFERENTIATION AND EXPRESSION OF SET7/9. WESTERN BLOT ANALYSIS AND QUANTITATIVE REAL-TIME POLYMERASE CHAIN REACTION WERE PERFORMED TO ASSESS THE PROTEIN AND MRNA LEVELS OF SET7/9 RESPECTIVELY. THE CALCIUM CONTENT WAS MEASURED TO EVALUATE CALCIFICATION. RESULTS: OSTEOBLASTIC DIFFERENTIATION AND CALCIFICATION OF VSMCS AND DOWNREGULATION OF THE EXPRESSION OF SET7/9 WERE OBSERVED AFTER IS TREATMENT. THE AUTOPHAGY WAS ACTIVATED AFTER TREATMENT WITH IS, WHEREAS THE INHIBITION OF THE AUTOPHAGY PARTIALLY ATTENUATED THE EFFECT OF IS ON BOTH THE STIMULATION OF THE EXPRESSION OF RUNT-RELATED TRANSCRIPTION FACTOR 2 AND CALCIUM DEPOSITION. CONCLUSIONS: OUR DATA DEMONSTRATED THAT SET7/9 DOWNREGULATION AND AUTOPHAGY ACTIVATION MAY BE THE KEY MECHANISM OF IS-INDUCED VC IN CKD. 2019 4 3654 45 INDOXYL SULFATE ACCELERATES VASCULAR SMOOTH MUSCLE CELL CALCIFICATION VIA MICRORNA-29B DEPENDENT REGULATION OF WNT/BETA-CATENIN SIGNALING. VASCULAR CALCIFICATION (VC) IS A VERY COMMON PHENOMENON IN PATIENTS WITH CHRONIC KIDNEY DISEASE(CKD) AND IT INCREASES THE INCIDENCE OF CARDIOVASCULAR DISEASE AND LEADS TO HIGH MORTALITY IN CKD PATIENTS. IT HAS BEEN REPORTED THAT SOME MICRORNAS (MIRS) PLAY ROLES IN VASCULAR CALCIFICATION AS AN EPIGENETIC REGULATOR. INDOXYL SULFATE (IS) IS A PROTEIN-BOUND UREMIC TOXIN WHICH HAS BEEN PROVEN AS ONE OF THE MAJOR RISK FACTORS OF CARDIOVASCULAR DISEASE IN CKD. HERE WE INVESTIGATED WHETHER MICRORNA-29B (MIR-29B) IS INVOLVED IN IS-INDUCED VASCULAR CALCIFICATION. WE FOUND THAT VASCULAR MIR-29B WAS DOWN-REGULATED IN RADIAL ARTERIES OF PATIENTS WITH END-STAGE RENAL DISEASE. CONSISTENTLY, IS ALSO DECREASED MIR-29B EXPRESSION IN HUMAN AORTIC SMOOTH MUSCLE CELLS (HASMCS) AND POTENTIATED THEIR CALCIFICATION. MIR-29B MIMICS SIGNIFICANTLY SUPPRESSED, WHILE MIR-29B ANTI-MIR MARKEDLY ENHANCED, IS-INDUCED RUNT-RELATED TRANSCRIPTION FACTOR 2 AND OSTEOPONTIN EXPRESSION. THE EXPRESSION OF WNT7B/BETA-CATENIN IN RADIAL ARTERIES WAS HIGHER IN END STAGE RENAL DISEASE THAN IN CONTROL GROUP, AND IS INCREASED WNT7B/BETA-CATENIN EXPRESSION IN HASMCS AS EARLY AS 3DAYS AFTER STIMULATION. FURTHERMORE, MIR-29B MIMICS POTENTLY REPRESSED WNT7B/BETA-CATENIN PROTEIN EXPRESSION IN HASMCS, WHEREAS MIR-29B ANTI-MIR INCREASED THEIR EXPRESSION, INDICATING MIR-29B INDEED NEGATIVELY REGULATES WNT7B/BETA-CATENIN SIGNALING. DICKKOPF-1 PROTEIN, THE WNT/BETA-CATENIN SIGNALING INHIBITOR, SUPPRESSED ANTI-MIR-29B-ENHANCED HASMCS CALCIFICATION. OUR DATA THUS INDICATE THAT MIR-29B DOWNREGULATION AND WNT/BETA-CATENIN SIGNALING ACTIVATION MAY BE THE KEY MECHANISM OF IS INDUCED VASCULAR CALCIFICATION IN CHRONIC KIDNEY DISEASE. 2018 5 5596 36 ROLES OF HISTONE ACETYLATION MODIFIERS AND OTHER EPIGENETIC REGULATORS IN VASCULAR CALCIFICATION. VASCULAR CALCIFICATION (VC) IS CHARACTERIZED BY CALCIUM DEPOSITION INSIDE ARTERIES AND IS CLOSELY ASSOCIATED WITH THE MORBIDITY AND MORTALITY OF ATHEROSCLEROSIS, CHRONIC KIDNEY DISEASE, DIABETES, AND OTHER CARDIOVASCULAR DISEASES (CVDS). VC IS NOW WIDELY KNOWN TO BE AN ACTIVE PROCESS OCCURRING IN VASCULAR SMOOTH MUSCLE CELLS (VSMCS) INVOLVING MULTIPLE MECHANISMS AND FACTORS. THESE MECHANISMS SHARE FEATURES WITH THE PROCESS OF BONE FORMATION, SINCE THE PHENOTYPE SWITCHING FROM THE CONTRACTILE TO THE OSTEOCHONDROGENIC PHENOTYPE ALSO OCCURS IN VSMCS DURING VC. IN ADDITION, VC CAN BE REGULATED BY EPIGENETIC FACTORS, INCLUDING DNA METHYLATION, HISTONE MODIFICATION, AND NONCODING RNAS. ALTHOUGH VC IS COMMONLY OBSERVED IN PATIENTS WITH CHRONIC KIDNEY DISEASE AND CVD, SPECIFIC DRUGS FOR VC HAVE NOT BEEN DEVELOPED. THUS, DISCOVERING NOVEL THERAPEUTIC TARGETS MAY BE NECESSARY. IN THIS REVIEW, WE SUMMARIZE THE CURRENT EXPERIMENTAL EVIDENCE REGARDING THE ROLE OF EPIGENETIC REGULATORS INCLUDING HISTONE DEACETYLASES AND PROPOSE THE THERAPEUTIC IMPLICATION OF THESE REGULATORS IN THE TREATMENT OF VC. 2020 6 6700 39 VASCULAR CALCIFICATION MECHANISMS: UPDATES AND RENEWED INSIGHT INTO SIGNALING PATHWAYS INVOLVED IN HIGH PHOSPHATE-MEDIATED VASCULAR SMOOTH MUSCLE CELL CALCIFICATION. VASCULAR CALCIFICATION (VC) IS ASSOCIATED WITH AGING, CARDIOVASCULAR AND RENAL DISEASES AND RESULTS IN POOR MORBIDITY AND INCREASED MORTALITY. VC OCCURS IN PATIENTS WITH CHRONIC KIDNEY DISEASE (CKD), A CONDITION THAT IS ASSOCIATED WITH HIGH SERUM PHOSPHATE (PI) AND SEVERE CARDIOVASCULAR CONSEQUENCES. HIGH SERUM PI LEVEL IS RELATED TO SOME PATHOLOGIES WHICH AFFECT THE BEHAVIOUR OF VASCULAR CELLS, INCLUDING PLATELETS, ENDOTHELIAL CELLS (ECS) AND SMOOTH MUSCLE CELLS (SMCS), AND PLAYS A CENTRAL ROLE IN PROMOTING VC. VC IS A COMPLEX, ACTIVE AND CELL-MEDIATED PROCESS INVOLVING THE TRANSDIFFERENTIATION OF VASCULAR SMCS TO A BONE-LIKE PHENOTYPE, SYSTEMIC INFLAMMATION, DECREASED ANTI-CALCIFIC EVENTS (LOSS OF CALCIFICATION INHIBITORS), LOSS IN SMC LINEAGE MARKERS AND ENHANCED PRO-CALCIFIC MICRORNAS (MIRS), AN INCREASED INTRACELLULAR CALCIUM LEVEL, APOPTOSIS, ABERRANT DNA DAMAGE RESPONSE (DDR) AND SENESCENCE OF VASCULAR SMCS. THIS REVIEW GIVES A BRIEF OVERVIEW OF THE CURRENT KNOWLEDGE OF VC MECHANISMS WITH A PARTICULAR FOCUS ON PI-INDUCED CHANGES IN THE VASCULAR WALL IMPORTANT IN PROMOTING CALCIFICATION. IN ADDITION TO REVIEWING THE MAIN FINDINGS, THIS REVIEW ALSO SHEDS LIGHT ON DIRECTIONS FOR FUTURE RESEARCH IN THIS AREA AND DISCUSSES EMERGING PATHWAYS SUCH AS PI-REGULATED INTRACELLULAR CALCIUM SIGNALING, EPIGENETICS, OXIDATIVE DNA DAMAGE AND SENESCENCE-MEDIATED MECHANISMS THAT MAY PLAY CRITICAL, YET TO BE EXPLORED, REGULATORY AND DRUGGABLE ROLES IN LIMITING VC. 2021 7 6699 38 VASCULAR CALCIFICATION IN CKD: NEW INSIGHTS INTO ITS MECHANISMS. VASCULAR CALCIFICATION (VC) IS A COMMON COMPLICATION OF CHRONIC KIDNEY DISEASE (CKD) AND CONTRIBUTES TO AN INCREASED RISK OF CARDIOVASCULAR MORBIDITY AND MORTALITY. HOWEVER, EFFECTIVE THERAPIES ARE STILL UNAVAILABLE AT PRESENT. IT HAS BEEN WELL ESTABLISHED THAT VC ASSOCIATED WITH CKD IS NOT A PASSIVE PROCESS OF CALCIUM PHOSPHATE DEPOSITION, BUT AN ACTIVELY REGULATED AND CELL-MEDIATED PROCESS THAT SHARES MANY SIMILARITIES WITH BONE FORMATION. ADDITIONALLY, NUMEROUS STUDIES HAVE SUGGESTED THAT CKD PATIENTS HAVE SPECIFIC RISK FACTORS AND CONTRIBUTORS TO THE DEVELOPMENT OF VC, SUCH AS HYPERPHOSPHATEMIA, UREMIC TOXINS, OXIDATIVE STRESS AND INFLAMMATION. ALTHOUGH RESEARCH EFFORTS IN THE PAST DECADE HAVE GREATLY IMPROVED OUR KNOWLEDGE OF THE MULTIPLE FACTORS AND MECHANISMS INVOLVED IN CKD-RELATED VC, MANY QUESTIONS REMAIN UNANSWERED. MOREOVER, STUDIES FROM THE PAST DECADE HAVE DEMONSTRATED THAT EPIGENETIC MODIFICATIONS ABNORMALITIES, SUCH AS DNA METHYLATION, HISTONE MODIFICATIONS AND NONCODING RNAS, PLAY AN IMPORTANT ROLE IN THE REGULATION OF VC. THIS REVIEW SEEKS TO PROVIDE AN OVERVIEW OF THE PATHOPHYSIOLOGICAL AND MOLECULAR MECHANISMS OF VC ASSOCIATED WITH CKD, MAINLY FOCUSING ON THE INVOLVEMENT OF EPIGENETIC MODIFICATIONS IN THE INITIATION AND PROGRESSION OF UREMIC VC, WITH THE AIM TO DEVELOP PROMISING THERAPIES FOR CKD-RELATED CARDIOVASCULAR EVENTS IN THE FUTURE. 2023 8 3655 38 INDOXYL SULFATE ENHANCE THE HYPERMETHYLATION OF KLOTHO AND PROMOTE THE PROCESS OF VASCULAR CALCIFICATION IN CHRONIC KIDNEY DISEASE. CHRONIC KIDNEY DISEASE (CKD) IS A STATE OF KLOTHO DEFICIENCY. THE KLOTHO EXPRESSION MAY BE SUPPRESSED DUE TO DNA HYPERMETHYLATION IN CANCER CELLS SO WE HAVE INVESTIGATED THE EFFECTS AND POSSIBLE MECHANISMS BY WHICH KLOTHO EXPRESSION IS REGULATED IN HUMAN AORTIC SMOOTH MUSCLE CELLS (HASMCS). THE VASCULAR KLOTHO HYPERMETHYLATION IN RADIAL ARTERIES OF PATIENTS WITH END-STAGE RENAL DISEASE WAS DESCRIBED. CULTURED HASMCS AND 5/6-NEPHRECTOMIZED SPRAGUE DAWLEY (SD) RATS TREATED WITH INDOXYL SULFATE (IS) WERE USED AS IN VITRO AND IN VIVO MODELS, RESPECTIVELY. IS INCREASED CPG HYPERMETHYLATION OF THE KLOTHO GENE AND DECREASED KLOTHO EXPRESSION IN HASMCS, AND POTENTIATED HASMCS CALCIFICATION. THE EXPRESSION OF DNA METHYLTRANSFERASE (DNMT) 1 AND 3A IN HASMCS TREATED WITH IS WAS SIGNIFICANTLY INCREASED AND SPECIFIC INHIBITION OF DNA METHYLTRANSFERASE 1 BY 5-AZA-2'-DEOXYCYTIDINE(5AZA-2DC) CAUSED DEMETHYLATION OF THE KLOTHO GENE AND INCREASED KLOTHO EXPRESSION. IN RATS, INJECTION OF IS POTENTIATED VASCULAR CALCIFICATION, INCREASED CPG HYPERMETHYLATION OF THE KLOTHO GENE AND DECREASED KLOTHO EXPRESSION IN THE AORTIC MEDIAL LAYER AND ALL OF THESE CHANGES COULD BE REVERTED BY 5AZA-2DC TREATMENT. TRANSCRIPTIONAL SUPPRESSION OF VASCULAR KLOTHO GENE EXPRESSION BY IS AND EPIGENETIC MODIFICATION OF KLOTHO BY IS MAY BE AN IMPORTANT PATHOLOGICAL MECHANISM OF VASCULAR CALCIFICATION IN CKD. 2016 9 3295 49 HIGH PHOSPHATE-INDUCED DOWNREGULATION OF PPARGAMMA CONTRIBUTES TO CKD-ASSOCIATED VASCULAR CALCIFICATION. MEDIAL ARTERIAL CALCIFICATION ASSOCIATED WITH HYPERPHOSPHATEMIA IS A MAIN CAUSE OF CARDIOVASCULAR MORTALITY IN PATIENTS WITH CHRONIC KIDNEY DISEASE (CKD), BUT THE MECHANISMS UNDERLYING HIGH PHOSPHATE-INDUCED VASCULAR CALCIFICATION REMAIN LARGELY UNKNOWN. HERE, WE OBSERVED A SIGNIFICANT DECREASE IN THE EXPRESSION OF PEROXISOME PROLIFERATOR-ACTIVATED RECEPTOR-GAMMA (PPARGAMMA) IN CALCIFIED ARTERIES BOTH IN CKD PATIENTS AND IN A MOUSE MODEL OF CKD WITH HYPERPHOSPHATEMIA. IN VITRO, HIGH PHOSPHATE TREATMENT LED TO A DECREASED EXPRESSION OF PPARGAMMA IN MOUSE VASCULAR SMOOTH MUSCLE CELLS (VMSCS), ACCOMPANIED BY APPARENT OSTEOGENIC DIFFERENTIATION AND CALCIFICATION. PRETREATMENT WITH PPARGAMMA AGONIST ROSIGLITAZONE SIGNIFICANTLY REVERSED HIGH PHOSPHATE-INDUCED VSMCS CALCIFICATION. FURTHER INVESTIGATION SHOWED THAT METHYL-CPG BINDING PROTEIN 2 (MECP2)-MEDIATED EPIGENETIC REPRESSION WAS INVOLVED IN HIGH PHOSPHATE-INDUCED PPARGAMMA DOWNREGULATION. MOREOVER, THE EXPRESSION OF KLOTHO THAT HAS THE ABILITY TO INHIBIT VASCULAR CALCIFICATION BY REGULATING PHOSPHATE UPTAKE DECREASED WITH THE PPARGAMMA REDUCTION IN VSMCS AFTER HIGH PHOSPHATE TREATMENT, AND ROSIGLITAZONE FAILED TO INHIBIT HIGH PHOSPHATE-INDUCED CALCIFICATION IN VSMCS WITH KNOCKDOWN OF KLOTHO OR IN AORTIC RINGS FROM KLOTHO-DEFICIENT (KL/KL) MICE. FINALLY, AN IN VIVO STUDY DEMONSTRATED THAT ORAL ADMINISTRATION OF ROSIGLITAZONE COULD INCREASE KLOTHO EXPRESSION AND PROTECT AGAINST HIGH PHOSPHATE-INDUCED VASCULAR CALCIFICATION IN CKD MICE. THESE FINDINGS SUGGEST THAT THE INHIBITION OF PPARGAMMA EXPRESSION MAY CONTRIBUTE TO THE PATHOGENESIS OF HIGH PHOSPHATE-INDUCED VASCULAR CALCIFICATION, WHICH MAY PROVIDE A NEW THERAPEUTIC TARGET FOR VASCULAR CALCIFICATION IN CKD PATIENTS. 2018 10 6122 27 THE EPIGENETIC LANDSCAPE OF VASCULAR CALCIFICATION: AN INTEGRATIVE PERSPECTIVE. VASCULAR CALCIFICATION (VC) IS AN IMPORTANT COMPLICATION AMONG PATIENTS OF ADVANCED AGE, THOSE WITH CHRONIC KIDNEY DISEASE, AND THOSE WITH DIABETES MELLITUS. THE PATHOPHYSIOLOGY OF VC ENCOMPASSES PASSIVE OCCURRENCE OF PHYSICO-CHEMICAL CALCIUM DEPOSITION, ACTIVE CELLULAR SECRETION OF OSTEOID MATRIX UPON EXPOSURE TO METABOLICALLY NOXIOUS STIMULI, OR A VARIABLE COMBINATION OF BOTH PROCESSES. EPIGENETIC ALTERATIONS HAVE BEEN SHOWN TO PARTICIPATE IN THIS COMPLEX ENVIRONMENT, THROUGH MECHANISMS INCLUDING DNA METHYLATION, NON-CODING RNAS, HISTONE MODIFICATIONS, AND CHROMATIN CHANGES. DESPITE SUCH IMPORTANCE, EXISTING REVIEWS FAIL TO PROVIDE A COMPREHENSIVE VIEW OF ALL RELEVANT REPORTS ADDRESSING EPIGENETIC PROCESSES IN VC, AND CROSS-TALK BETWEEN DIFFERENT EPIGENETIC MACHINERIES IS RARELY EXAMINED. WE CONDUCTED A SYSTEMATIC REVIEW BASED ON PUBMED AND MEDLINE DATABASES UP TO 30 SEPTEMBER 2019, TO IDENTIFY CLINICAL, TRANSLATIONAL, AND EXPERIMENTAL REPORTS ADDRESSING EPIGENETIC PROCESSES IN VC; WE RETRIEVED 66 ORIGINAL STUDIES, AMONG WHICH 60.6% LOOKED INTO THE PATHOGENIC ROLE OF NON-CODING RNA, FOLLOWED BY DNA METHYLATION (12.1%), HISTONE MODIFICATION (9.1%), AND CHROMATIN CHANGES (4.5%). NINE (13.6%) REPORTS EXAMINED THE DISCREPANCY OF EPIGENETIC SIGNATURES BETWEEN SUBJECTS OR TISSUES WITH AND WITHOUT VC, SUPPORTING THEIR APPLICABILITY AS BIOMARKERS. ASSISTED BY BIOINFORMATIC ANALYSES BLENDING IN EACH EPIGENETIC COMPONENT, WE DISCOVERED PROMINENT INTERACTIONS BETWEEN MICRORNAS, DNA METHYLATION, AND HISTONE MODIFICATION REGARDING POTENTIAL INFLUENCES ON VC RISK. 2020 11 4415 37 MOLECULAR AND CELLULAR MECHANISMS THAT INDUCE ARTERIAL CALCIFICATION BY INDOXYL SULFATE AND P-CRESYL SULFATE. THE PROTEIN-BOUND UREMIC TOXINS, INDOXYL SULFATE (IS) AND P-CRESYL SULFATE (PCS), ARE CONSIDERED TO BE HARMFUL VASCULAR TOXINS. ARTERIAL MEDIA CALCIFICATION, OR THE DEPOSITION OF CALCIUM PHOSPHATE CRYSTALS IN THE ARTERIES, CONTRIBUTES SIGNIFICANTLY TO CARDIOVASCULAR COMPLICATIONS, INCLUDING LEFT VENTRICULAR HYPERTROPHY, HYPERTENSION, AND IMPAIRED CORONARY PERFUSION IN THE ELDERLY AND PATIENTS WITH CHRONIC KIDNEY DISEASE (CKD) AND DIABETES. RECENTLY, WE REPORTED THAT BOTH IS AND PCS TRIGGER MODERATE TO SEVERE CALCIFICATION IN THE AORTA AND PERIPHERAL VESSELS OF CKD RATS. THIS REVIEW DESCRIBES THE MOLECULAR AND CELLULAR MECHANISMS BY WHICH THESE UREMIC TOXINS INDUCE ARTERIAL MEDIA CALCIFICATION. A COMPLEX INTERPLAY BETWEEN INFLAMMATION, COAGULATION, AND LIPID METABOLISM PATHWAYS, INFLUENCED BY EPIGENETIC FACTORS, IS CRUCIAL IN IS/PCS-INDUCED ARTERIAL MEDIA CALCIFICATION. HIGH LEVELS OF GLUCOSE ARE LINKED TO THESE EVENTS, SUGGESTING THAT A GOOD BALANCE BETWEEN GLUCOSE AND LIPID LEVELS MIGHT BE IMPORTANT. ON THE CELLULAR LEVEL, EFFECTS ON ENDOTHELIAL CELLS, WHICH ACT AS THE PRIMARY SENSORS OF CIRCULATING PATHOLOGICAL TRIGGERS, MIGHT BE AS IMPORTANT AS THOSE ON VASCULAR SMOOTH MUSCLE CELLS. ENDOTHELIAL DYSFUNCTION, PROVOKED BY IS AND PCS TRIGGERED OXIDATIVE STRESS, MAY BE CONSIDERED A KEY EVENT IN THE ONSET AND DEVELOPMENT OF ARTERIAL MEDIA CALCIFICATION. IN THIS REVIEW A NUMBER OF IMPORTANT OUTSTANDING QUESTIONS SUCH AS THE ROLE OF MIRNA'S, PHENOTYPIC SWITCHING OF BOTH ENDOTHELIAL AND VASCULAR SMOOTH MUSCLE CELLS AND NEW TYPES OF PROGRAMMED CELL DEATH IN ARTERIAL MEDIA CALCIFICATION RELATED TO PROTEIN-BOUND UREMIC TOXINS ARE PUT FORWARD AND DISCUSSED. 2020 12 3656 43 INDUCIBLE PRMT1 ABLATION IN ADULT VASCULAR SMOOTH MUSCLE LEADS TO CONTRACTILE DYSFUNCTION AND AORTIC DISSECTION. VASCULAR SMOOTH MUSCLE CELLS (VSMCS) HAVE REMARKABLE PLASTICITY IN RESPONSE TO DIVERSE ENVIRONMENTAL CUES. ALTHOUGH THESE CELLS ARE VERSATILE, CHRONIC STRESS CAN TRIGGER VSMC DYSFUNCTION, WHICH ULTIMATELY LEADS TO VASCULAR DISEASES SUCH AS AORTIC ANEURYSM AND ATHEROSCLEROSIS. PROTEIN ARGININE METHYLTRANSFERASE 1 (PRMT1) IS A MAJOR ENZYME CATALYZING ASYMMETRIC ARGININE DIMETHYLATION OF PROTEINS THAT ARE SOURCES OF ASYMMETRIC DIMETHYLARGININE (ADMA), AN ENDOGENOUS INHIBITOR OF NITRIC OXIDE SYNTHASE. ALTHOUGH A POTENTIAL ROLE OF PRMT1 IN VASCULAR PATHOGENESIS HAS BEEN PROPOSED, ITS ROLE IN VASCULAR FUNCTION HAS YET TO BE CLARIFIED. HERE, WE INVESTIGATED THE ROLE AND UNDERLYING MECHANISM OF PRMT1 IN VASCULAR SMOOTH MUSCLE CONTRACTILITY AND FUNCTION. THE EXPRESSION OF PRMT1 AND CONTRACTILE-RELATED GENES WAS SIGNIFICANTLY DECREASED IN THE AORTAS OF ELDERLY HUMANS AND PATIENTS WITH AORTIC ANEURYSMS. MICE WITH VSMC-SPECIFIC PRMT1 ABLATION (SMKO) EXHIBITED PARTIAL LETHALITY, LOW BLOOD PRESSURE AND AORTIC DILATION. THE PRMT1-ABLATED AORTAS SHOWED AORTIC DISSECTION WITH ELASTIC FIBER DEGENERATION AND CELL DEATH. EX VIVO AND IN VITRO ANALYSES INDICATED THAT PRMT1 ABLATION SIGNIFICANTLY DECREASED THE CONTRACTILITY OF THE AORTA AND TRACTION FORCES OF VSMCS. PRMT1 ABLATION DOWNREGULATED THE EXPRESSION OF CONTRACTILE GENES SUCH AS MYOCARDIN WHILE UPREGULATING THE EXPRESSION OF SYNTHETIC GENES, THUS CAUSING THE CONTRACTILE TO SYNTHETIC PHENOTYPIC SWITCH OF VSMCS. IN ADDITION, MECHANISTIC STUDIES DEMONSTRATED THAT PRMT1 DIRECTLY REGULATES MYOCARDIN GENE ACTIVATION BY MODULATING EPIGENETIC HISTONE MODIFICATIONS IN THE MYOCARDIN PROMOTER REGION. THUS, OUR STUDY DEMONSTRATES THAT VSMC PRMT1 IS ESSENTIAL FOR VASCULAR HOMEOSTASIS AND THAT ITS ABLATION CAUSES AORTIC DILATION/DISSECTION THROUGH IMPAIRED MYOCARDIN EXPRESSION. 2021 13 3306 38 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 14 6043 29 THE COMBINED PROGNOSTIC SIGNIFICANCE OF ALKALINE PHOSPHATASE AND INTRACRANIAL ARTERIAL CALCIFICATIONS IN HEMODIALYSIS PATIENTS. INTRODUCTION: THE PREVALENCE OF INTRACRANIAL ARTERIAL CALCIFICATION (ICAC) IN MAINTENANCE HEMODIALYSIS (MHD) PATIENTS IS ABOUT 90%, AND ITS SEVERITY IS CORRELATED WITH AGE, HEMODIALYSIS VINTAGE, AND MINERAL BONE DISEASE. ELEVATED CONCENTRATIONS OF CALCIUM AND PHOSPHORUS ARE NOT SUFFICIENT FOR MEDIAL CALCIFICATION BECAUSE OF INHIBITION BY PYROPHOSPHATE. ALKALINE PHOSPHATASE (ALP) PROMOTES CALCIFICATION BY HYDROLYZING EXTRACELLULAR PYROPHOSPHATE. EPIGENETIC MECHANISMS INVOLVING ALP INHIBITION BY APABETALONE WERE INVESTIGATED AS A POTENTIAL TARGET FOR PREVENTING VASCULAR CALCIFICATIONS (VCS). THIS STUDY ASSESSED THE COMBINED IMPACT OF VCS AND ELEVATED SERUM ALP ON MORTALITY AMONG CHRONIC HD PATIENTS. METHODS: VCS REPRESENTED BY ICAC WERE MEASURED SIMULTANEOUSLY WITH MINERAL BONE DISEASE PARAMETERS INCLUDING SERUM ALP OF MHD PATIENTS WHO UNDERWENT NONCONTRAST BRAIN COMPUTED TOMOGRAPHY FROM 2015 TO 2018 IN OUR INSTITUTION. RESULTS: THIS RETROSPECTIVE STUDY INCLUDED 150 MHD PATIENTS (MEAN AGE 71.3 +/- 12.1 YEARS, 60.1% MALE). OF THE TOTAL COHORT, 12 (7.8%) HAD NO BRAIN CALCIFICATIONS AND 69 (45.1%) HAD MULTIPLE INTRACRANIAL CALCIFICATIONS. CONSIDERING THE PATIENTS WITH NORMAL ALP AND NO CALCIFICATION AS THE REFERENCE GROUP YIELDED ADJUSTED ODDS RATIOS FOR ALL-CAUSE MORTALITY OF 4.6 (95% CI: 1.7-12.7) AMONG PATIENTS WITH BRAIN CALCIFICATIONS AND NORMAL ALP (P = 0.003) AND ODDS RATIOS FOR ALL-CAUSE MORTALITY OF 6.1 (95% CI: 2.1-17.7) AMONG PATIENTS WITH BRAIN CALCIFICATIONS AND ELEVATED ALP (P= 0.001). CONCLUSION: WE FOUND AN INDEPENDENT ASSOCIATION BETWEEN ICAC AND THE RISK OF DEATH AMONG MHD PATIENTS. THE COMBINED EFFECT OF ICAC AND ELEVATED ALP WAS ASSOCIATED WITH A HIGHER ODDS RATIO FOR ALL-CAUSE MORTALITY IN MHD PATIENTS AND MAY CONTRIBUTE TO THE RISK STRATIFICATION OF THESE PATIENTS. 2021 15 5536 33 ROLE OF C-MIR-21, C-MIR-126, REDOX STATUS, AND INFLAMMATORY CONDITIONS AS POTENTIAL PREDICTORS OF VASCULAR DAMAGE IN T2DM PATIENTS. THE DEVELOPMENT OF TYPE 2 DIABETES MELLITUS (T2DM) VASCULAR COMPLICATIONS (VCS) IS ASSOCIATED WITH OXIDATIVE STRESS AND CHRONIC INFLAMMATION AND CAN RESULT IN ENDOTHELIAL DYSFUNCTIONS. CIRCULATING MICRORNAS PLAY AN IMPORTANT ROLE IN EPIGENETIC REGULATION OF THE ETIOLOGY OF T2DM. WE STUDIED 30 HEALTHY VOLUNTEERS, 26 T2DM PATIENTS WITH NO COMPLICATIONS, AND 26 T2DM PATIENTS WITH VCS, TO LOOK FOR NEW BIOMARKERS INDICATING A RISK OF DEVELOPING VCS IN T2DM PATIENTS. PERIPHERAL BLOOD SAMPLES WERE USED TO DETERMINE REDOX STATE, BY MEASURING THE ENDOGENOUS ANTIOXIDANT DEFENSE SYSTEM (SUPEROXIDE DISMUTASE, SOD; CATALASE, CAT; GLUTATHIONE REDUCTASE, GRD; GLUTATHIONE PEROXIDASE, GPX; AND GLUCOSE-6-PHOSPHATE DEHYDROGENASE, G6DP) AND MARKERS OF OXIDATIVE DAMAGE (ADVANCED OXIDATION PROTEIN PRODUCTS, AOPP; LIPID PEROXIDATION, LPO). ADDITIONALLY, INFLAMMATORY MARKER LEVELS (IL-1, IL-6, IL-18, AND TNF-ALPHA), C-MIR-21, AND C-MIR-126 EXPRESSION WERE ANALYZED. T2DM PATIENTS SHOWED THE HIGHEST OXIDATIVE DAMAGE WITH INCREASED GSSG/GSH RATIOS, LPO, AND AOPP LEVELS. IN BOTH DIABETIC GROUPS, WE FOUND THAT DIMINISHED SOD ACTIVITY WAS ACCOMPANIED BY INCREASED CAT AND DECREASED GRD AND G6PD ACTIVITIES. DIABETIC PATIENTS PRESENTED WITH INCREASED RELATIVE EXPRESSION OF C-MIR-21 AND DECREASED RELATIVE EXPRESSION OF C-MIR-126. OVERALL, C-MIR-21, SOD, CAT, AND IL-6 HAD HIGH PREDICTIVE VALUES FOR DIABETES DIAGNOSES. FINALLY, OUR DATA DEMONSTRATED THAT IL-6 EXHIBITED PREDICTIVE VALUE FOR VC DEVELOPMENT IN THE STUDIED POPULATION. MOREOVER, C-MIR-21 AND C-MIR-126, ALONG WITH GPX AND AOPP LEVELS, SHOULD BE CONSIDERED POSSIBLE MARKERS FOR VC DEVELOPMENT IN FUTURE STUDIES. 2022 16 4303 37 MICRORNA-223 INHIBITS TISSUE FACTOR EXPRESSION IN VASCULAR ENDOTHELIAL CELLS. OBJECTIVE: ATHEROSCLEROSIS IS A CHRONIC INFLAMMATORY PROCESS, IN WHICH VASCULAR ENDOTHELIAL CELLS (ECS) BECOME DYSFUNCTIONAL OWING TO THE EFFECTS OF CHEMICAL SUBSTANCES, SUCH AS INFLAMMATORY FACTOR AND GROWTH FACTORS. TISSUE FACTOR (TF) EXPRESSION IS INDUCED BY THE ABOVE CHEMICAL SUBSTANCES IN ACTIVATED ECS. TF INITIATES THROMBOSIS ON DISRUPTED ATHEROSCLEROTIC PLAQUES WHICH PLAYS AN ESSENTIAL ROLE DURING THE ONSET OF ACUTE CORONARY SYNDROMES (ACS). INCREASING EVIDENCES SUGGEST THE IMPORTANT ROLE OF MICRORNAS AS EPIGENETIC REGULATORS OF ATHEROSCLEROTIC DISEASE. THE AIM OF OUR STUDY IS TO IDENTIFY IF MICRORNA-223 (MIR-223) TARGETS TF IN ECS. METHODS AND RESULTS: BIOINFORMATIC ANALYSIS SHOWED THAT TF IS A TARGET CANDIDATE OF MIR-223. WESTERN BLOTTING ANALYSIS REVEALED THAT TUMOR NECROSIS FACTOR ALPHA (TNF-ALPHA) INCREASED TF EXPRESSION IN AORTA OF C57BL/6J MICE AND CULTURED ECS (EA.HY926 CELLS AND HUVEC) AFTER 4 H TREATMENT. IN TNF-ALPHA TREATED ECS, TF MRNA WAS ALSO INCREASED MEASURED BY REAL-TIME PCR. REAL-TIME PCR RESULTS SHOWED THAT MIR-223 LEVELS WERE DOWNREGULATED IN TNF-ALPHA-TREATED AORTA OF C57BL/6J MICE AND CULTURED ECS. TRANSFECTION OF ECS WITH MIR-223 MIMIC OR MIR-223 INHIBITOR MODIFIED TF EXPRESSION BOTH IN MRNA AND PROTEIN LEVELS. LUCIFERASE ASSAYS CONFIRMED THAT MIR-223 SUPPRESSED TF EXPRESSION BY BINDING TO THE SEQUENCE OF TF 3'-UNTRANSLATED REGIONS (3'UTR). TF PROCOAGULANT ACTIVITY WAS INHIBITED BY OVEREXPRESSING MIR-223 WITH OR WITHOUT TNF-ALPHA STIMULATION. CONCLUSIONS: MIR-223-MEDIATED SUPPRESSION OF TF EXPRESSION PROVIDES A NOVEL MOLECULAR MECHANISM FOR THE REGULATION OF COAGULATION CASCADE, AND SUGGESTS A CLUE AGAINST THROMBOGENESIS DURING THE PROCESS OF ATHEROSCLEROTIC PLAQUE RUPTURE. 2014 17 446 35 APABETALONE DOWNREGULATES FIBROTIC, INFLAMMATORY AND CALCIFIC PROCESSES IN RENAL MESANGIAL CELLS AND PATIENTS WITH RENAL IMPAIRMENT. EPIGENETIC MECHANISMS ARE IMPLICATED IN TRANSCRIPTIONAL PROGRAMS DRIVING CHRONIC KIDNEY DISEASE (CKD). APABETALONE IS AN ORALLY AVAILABLE INHIBITOR OF BROMODOMAIN AND EXTRATERMINAL (BET) PROTEINS, WHICH ARE EPIGENETIC READERS THAT MODULATE GENE EXPRESSION. IN THE PHASE 3 BETONMACE TRIAL, APABETALONE REDUCED RISK OF MAJOR ADVERSE CARDIAC EVENTS (MACE) BY 50% IN THE CKD SUBPOPULATION, INDICATING FAVORABLE EFFECTS ALONG THE KIDNEY-HEART AXIS. ACTIVATION OF HUMAN RENAL MESANGIAL CELLS (HRMCS) TO A CONTRACTILE PHENOTYPE THAT OVERPRODUCES EXTRACELLULAR MATRIX (ECM) AND INFLAMMATORY CYTOKINES, AND PROMOTES CALCIFICATION, FREQUENTLY ACCOMPANIES CKD TO DRIVE PATHOLOGY. HERE, WE SHOW APABETALONE DOWNREGULATED HRMC ACTIVATION WITH TGF-BETA1 STIMULATION BY SUPPRESSING TGF-BETA1-INDUCED ALPHA-SMOOTH MUSCLE ACTIN (ALPHA-SMA) EXPRESSION, ALPHA-SMA ASSEMBLY INTO STRESS FIBERS, ENHANCED CONTRACTION, COLLAGEN OVERPRODUCTION, AND EXPRESSION OF KEY DRIVERS OF FIBROSIS, INFLAMMATION, OR CALCIFICATION INCLUDING THROMBOSPONDIN, FIBRONECTIN, PERIOSTIN, SPARC, INTERLEUKIN 6, AND ALKALINE PHOSPHATASE. LIPOPOLYSACCHARIDE-STIMULATED EXPRESSION OF INFLAMMATORY GENES IL6, IL1B, AND PTGS2 WAS ALSO SUPPRESSED. TRANSCRIPTOMICS CONFIRMED APABETALONE AFFECTED GENE SETS OF ECM REMODELING AND INTEGRINS. CLINICAL TRANSLATION OF IN VITRO RESULTS WAS INDICATED IN CKD PATIENTS WHERE A SINGLE DOSE OF APABETALONE REDUCED PLASMA LEVELS OF KEY PRO-FIBROTIC AND INFLAMMATORY MARKERS, AND INDICATED INHIBITION OF TGF-BETA1 SIGNALING. WHILE PLASMA PROTEINS CANNOT BE TRACED TO THE KIDNEY ALONE, ANTI-FIBROTIC AND ANTI-INFLAMMATORY EFFECTS OF APABETALONE IDENTIFIED IN THIS STUDY ARE CONSISTENT WITH THE OBSERVED DECREASE IN CARDIOVASCULAR RISK IN CKD PATIENTS. 2023 18 3887 24 KLOTHO METHYLATION IS LINKED TO UREMIC TOXINS AND CHRONIC KIDNEY DISEASE. EPIGENETIC REGULATION PLAYS A MAJOR ROLE IN UREMIC TOXIN-INDUCED CHRONIC KIDNEY DISEASE (CKD) PROGRESSION. THE KLOTHO PROTEIN IS A KEY MODULATOR OF HOMEOSTASIS IN RENAL FUNCTION. UREMIC TOXIN ACCUMULATION CAN INDUCE DNA METHYLTRANSFERASE (DNMT) PROTEIN EXPRESSION, WHICH IS INVOLVED IN THE SILENCING OF KLOTHO THROUGH HYPERMETHYLATION. TREATMENT WITH DNMT INHIBITORS CAN INDUCE A HYPERMETHYLATED STATUS OF KLOTHO AND SUPPRESS MRNA AND PROTEIN EXPRESSION. EPIGENETIC TARGETING OF SPECIFIC GENES MAY BECOME AN EFFECTIVE STRATEGY TO PREVENT PROGRESSION OF UREMIA-RELATED CKD. 2012 19 444 35 AORTIC AND CAROTID ARTERIAL STIFFNESS AND EPIGENETIC REGULATOR GENE EXPRESSION CHANGES PRECEDE BLOOD PRESSURE RISE IN STROKE-PRONE DAHL SALT-SENSITIVE HYPERTENSIVE RATS. MULTIPLE CLINICAL STUDIES SHOW THAT ARTERIAL STIFFNESS, MEASURED AS PULSE WAVE VELOCITY (PWV), PRECEDES HYPERTENSION AND IS AN INDEPENDENT PREDICTOR OF HYPERTENSION END ORGAN DISEASES INCLUDING STROKE, CARDIOVASCULAR DISEASE AND CHRONIC KIDNEY DISEASE. RISK FACTOR STUDIES FOR ARTERIAL STIFFNESS IMPLICATE AGE, HYPERTENSION AND SODIUM. HOWEVER, CAUSAL MECHANISMS LINKING RISK FACTOR TO ARTERIAL STIFFNESS REMAIN TO BE ELUCIDATED. HERE, WE STUDIED THE CAUSAL RELATIONSHIP OF ARTERIAL STIFFNESS AND HYPERTENSION IN THE NA-INDUCED, STROKE-PRONE DAHL SALT-SENSITIVE (S) HYPERTENSIVE RAT MODEL, AND ANALYZED PUTATIVE MOLECULAR MECHANISMS. STROKE-PRONE AND NON-STROKE-PRONE MALE AND FEMALE RATS WERE STUDIED AT 3- AND 6-WEEKS OF AGE FOR ARTERIAL STIFFNESS (PWV, STRAIN), BLOOD PRESSURE, VESSEL WALL HISTOLOGY, AND GENE EXPRESSION CHANGES. STUDIES SHOWED THAT INCREASED LEFT CAROTID AND AORTIC ARTERIAL STIFFNESS PRECEDED HYPERTENSION, PULSE PRESSURE WIDENING, AND STRUCTURAL WALL CHANGES AT THE 6-WEEK TIME-POINT. INSTEAD, DIFFERENTIAL GENE INDUCTION WAS DETECTED IMPLICATING MOLECULAR-FUNCTIONAL CHANGES IN EXTRACELLULAR MATRIX (ECM) STRUCTURAL CONSTITUENTS, MODIFIERS, CELL ADHESION, AND MATRICELLULAR PROTEINS, AS WELL AS IN ENDOTHELIAL FUNCTION, APOPTOSIS BALANCE, AND EPIGENETIC REGULATORS. IMMUNOSTAINING TESTING HISTONE MODIFIERS EP300, HDAC3, AND PRMT5 LEVELS CONFIRMED CAROTID ARTERY-UPREGULATION IN ALL THREE LAYERS: ENDOTHELIAL, SMOOTH MUSCLE AND ADVENTITIAL CELLS. OUR STUDY RECAPITULATES OBSERVATIONS IN HUMANS THAT GIVEN SALT-SENSITIVITY, INCREASED NA-INTAKE INDUCED ARTERIAL STIFFNESS BEFORE HYPERTENSION, INCREASED PULSE PRESSURE, AND STRUCTURAL VESSEL WALL CHANGES. DIFFERENTIAL GENE EXPRESSION CHANGES ASSOCIATED WITH ARTERIAL STIFFNESS SUGGEST A MOLECULAR MECHANISM LINKING SODIUM TO FULL-VESSEL WALL RESPONSE AFFECTING GENE-NETWORKS INVOLVED IN VASCULAR ECM STRUCTURE-FUNCTION, APOPTOSIS BALANCE, AND EPIGENETIC REGULATION. 2014 20 6453 29 THIOREDOXIN INTERACTING PROTEIN (TXNIP) INDUCES INFLAMMATION THROUGH CHROMATIN MODIFICATION IN RETINAL CAPILLARY ENDOTHELIAL CELLS UNDER DIABETIC CONDITIONS. CHRONIC HYPERGLYCEMIA AND ACTIVATION OF RECEPTOR FOR ADVANCED GLYCATION END PRODUCTS (RAGE) ARE KNOWN RISK FACTORS FOR MICROVASCULAR DISEASE DEVELOPMENT IN DIABETIC RETINOPATHY. THIOREDOXIN-INTERACTING PROTEIN (TXNIP), AN ENDOGENOUS INHIBITOR OF ANTIOXIDANT THIOREDOXIN (TRX), PLAYS A CAUSATIVE ROLE IN DIABETES AND ITS VASCULAR COMPLICATIONS. HEREIN WE INVESTIGATE WHETHER HG AND RAGE INDUCE INFLAMMATION IN RAT RETINAL ENDOTHELIAL CELLS (EC) UNDER DIABETIC CONDITIONS IN CULTURE THROUGH TXNIP ACTIVATION AND WHETHER EPIGENETIC MECHANISMS PLAY A ROLE IN INFLAMMATORY GENE EXPRESSION. WE SHOW THAT RAGE ACTIVATION BY ITS LIGAND S100B OR HG TREATMENT OF RETINAL EC INDUCES THE EXPRESSION OF TXNIP AND INFLAMMATORY GENES SUCH AS COX2, VEGF-A, AND ICAM1. TXNIP SILENCING BY SIRNA IMPEDES RAGE AND HG EFFECTS WHILE STABLE OVER-EXPRESSION OF A CDNA FOR HUMAN TXNIP IN EC ELEVATES INFLAMMATION. P38 MAPK-NF-KAPPAB SIGNALING PATHWAY AND HISTONE H3 LYSINE (K) NINE MODIFICATIONS ARE INVOLVED IN TXNIP-INDUCED INFLAMMATION. CHROMATIN IMMUNOPRECIPITATION (CHIP) ASSAYS REVEAL THAT TXNIP OVER-EXPRESSION IN EC ABOLISHES H3K9 TRI-METHYLATION, A MARKER FOR GENE INACTIVATION, AND INCREASES H3K9 ACETYLATION, AN INDICATOR OF GENE INDUCTION, AT PROXIMAL COX2 PROMOTER BEARING THE NF-KAPPAB-BINDING SITE. THESE FINDINGS HAVE IMPORTANT IMPLICATIONS TOWARD UNDERSTANDING THE MOLECULAR MECHANISMS OF OCULAR INFLAMMATION AND ENDOTHELIAL DYSFUNCTION IN DIABETIC RETINOPATHY. 2009