1 2490 101 EPIGENETICALLY REGULATED INFLAMMATION IN VASCULAR SENESCENCE AND RENAL PROGRESSION OF CHRONIC KIDNEY DISEASE. CHRONIC KIDNEY DISEASE (CKD) AND ITS COMPLICATIONS, INCLUDING VASCULAR SENESCENCE AND PROGRESSIVE RENAL FIBROSIS, ARE ASSOCIATED WITH INFLAMMATION. VASCULAR SENESCENCE, IN PARTICULAR, HAS EMERGED AS AN INSTRUMENTAL MEDIATOR OF VASCULAR INFLAMMATION THAT POTENTIALLY WORSENS RENAL FUNCTION. EPIGENETICALLY REGULATED INFLAMMATION INVOLVING HISTONE MODIFICATION, DNA METHYLATION, ACTIONS OF MICRORNAS AND OTHER NON-CODING RNAS, AND THEIR RECIPROCAL REACTIONS DURING VASCULAR SENESCENCE AND INFLAMMAGING ARE UNDERAPPRECIATED. THEIR SYNERGISTIC EFFECTS CAN CONTRIBUTE TO CKD PROGRESSION. VASCULAR SENOTHERAPEUTICS OR PHARMACOLOGICAL ANTI-SENESCENT THERAPIES BASED ON EPIGENETIC MACHINERIES CAN THEREFORE BE PLAUSIBLE OPTIONS FOR AMELIORATING VASCULAR AGING AND EVEN HALTING THE WORSENING OF RENAL FIBROSIS. THESE INCLUDE HISTONE DEACETYLASE MODULATORS, HISTONE METHYLTRANSFERASE MODULATORS, OTHER HISTONE MODIFICATION EFFECTORS, DNA METHYLTRANSFERASE INHIBITORS, TELOMERASE REVERSE TRANSCRIPTASE ENHANCERS, MICRORNA MIMIC DELIVERY, AND SMALL MOLECULES WITH MICRORNA-REGULATING POTENTIALS. SOME OF THESE MOLECULES HAVE ALREADY BEEN TESTED AND HAVE SHOWN ANECDOTAL EVIDENCE FOR TREATING UREMIC VASCULOPATHY AND RENAL FIBROSIS, SUPPORTING THE FEASIBILITY OF THIS APPROACH. 2022 2 2195 35 EPIGENETIC MODIFICATION MECHANISMS INVOLVED IN INFLAMMATION AND FIBROSIS IN RENAL PATHOLOGY. THE GROWING INCIDENCE OF OBESITY, HYPERTENSION, AND DIABETES, COUPLED WITH THE AGING OF THE POPULATION, IS INCREASING THE PREVALENCE OF RENAL DISEASES IN OUR SOCIETY. CHRONIC KIDNEY DISEASE (CKD) IS CHARACTERIZED BY PERSISTENT INFLAMMATION, FIBROSIS, AND LOSS OF RENAL FUNCTION LEADING TO END-STAGE RENAL DISEASE. NOWADAYS, CKD TREATMENT HAS LIMITED EFFECTIVENESS UNDERSCORING THE IMPORTANCE OF THE DEVELOPMENT OF INNOVATIVE THERAPEUTIC OPTIONS. RECENT STUDIES HAVE IDENTIFIED HOW EPIGENETIC MODIFICATIONS PARTICIPATE IN THE SUSCEPTIBILITY TO CKD AND HAVE EXPLAINED HOW THE ENVIRONMENT INTERACTS WITH THE RENAL CELL EPIGENOME TO CONTRIBUTE TO RENAL DAMAGE. EPIGENETIC MECHANISMS REGULATE CRITICAL PROCESSES INVOLVED IN GENE REGULATION AND DOWNSTREAM CELLULAR RESPONSES. THE MOST RELEVANT EPIGENETIC MODIFICATIONS THAT PLAY A CRITICAL ROLE IN RENAL DAMAGE INCLUDE DNA METHYLATION, HISTONE MODIFICATIONS, AND CHANGES IN MIRNA LEVELS. IMPORTANTLY, THESE EPIGENETIC MODIFICATIONS ARE REVERSIBLE AND, THEREFORE, A SOURCE OF POTENTIAL THERAPEUTIC TARGETS. HERE, WE WILL EXPLAIN HOW EPIGENETIC MECHANISMS MAY REGULATE ESSENTIAL PROCESSES INVOLVED IN RENAL PATHOLOGY AND HIGHLIGHT SOME POSSIBLE EPIGENETIC THERAPEUTIC STRATEGIES FOR CKD TREATMENT. 2018 3 607 36 BEYOND GENETICS: EPIGENETIC CODE IN CHRONIC KIDNEY DISEASE. EPIGENETICS REFERS TO A HERITABLE CHANGE IN THE PATTERN OF GENE EXPRESSION THAT IS MEDIATED BY A MECHANISM SPECIFICALLY NOT DUE TO ALTERATIONS IN THE PRIMARY NUCLEOTIDE SEQUENCE. WELL-KNOWN EPIGENETIC MECHANISMS ENCOMPASS DNA METHYLATION, CHROMATIN REMODELING (HISTONE MODIFICATIONS), AND RNA INTERFERENCE. FUNCTIONALLY, EPIGENETICS PROVIDES AN EXTRA LAYER OF TRANSCRIPTIONAL CONTROL AND PLAYS A CRUCIAL ROLE IN NORMAL PHYSIOLOGICAL DEVELOPMENT, AS WELL AS IN PATHOLOGICAL CONDITIONS. ABERRANT DNA METHYLATION IS IMPLICATED IN IMMUNE DYSFUNCTION, INFLAMMATION, AND INSULIN RESISTANCE. EPIGENETIC CHANGES MAY BE RESPONSIBLE FOR 'METABOLIC MEMORY' AND DEVELOPMENT OF MICRO- AND MACROVASCULAR COMPLICATIONS OF DIABETES. MICRORNAS ARE CRITICAL IN THE MAINTENANCE OF GLOMERULAR HOMEOSTASIS AND HENCE RNA INTERFERENCE MAY BE IMPORTANT IN THE PROGRESSION OF RENAL DISEASE. RECENT STUDIES HAVE SHOWN THAT EPIGENETIC MODIFICATIONS ORCHESTRATE THE EPITHELIAL-MESENCHYMAL TRANSITION AND EVENTUALLY FIBROSIS OF THE RENAL TISSUE. OXIDATIVE STRESS, INFLAMMATION, HYPERHOMOCYSTEINEMIA, AND UREMIC TOXINS COULD INDUCE EPIMUTATIONS IN CHRONIC KIDNEY DISEASE. EPIGENETIC ALTERATIONS ARE ASSOCIATED WITH INFLAMMATION AND CARDIOVASCULAR DISEASE IN PATIENTS WITH CHRONIC KIDNEY DISEASE. REVERSIBLE NATURE OF THE EPIGENETIC CHANGES GIVES A UNIQUE OPPORTUNITY TO HALT OR EVEN REVERSE THE DISEASE PROCESS THROUGH TARGETED THERAPEUTIC STRATEGIES. 2011 4 5660 35 SEX-SPECIFIC EPIGENETIC PROGRAMMING IN RENAL FIBROSIS AND INFLAMMATION. THE GROWING PREVALENCE OF HYPERTENSION, HEART DISEASE, DIABETES, AND OBESITY ALONG WITH AN AGING POPULATION, IS LEADING TO HIGHER INCIDENCE OF RENAL DISEASES IN THE SOCIETY. CHRONIC KIDNEY DISEASE (CKD) IS CHARACTERIZED MAINLY BY PERSISTENT INFLAMMATION, FIBROSIS, AND GRADUAL LOSS OF RENAL FUNCTION LEADING TO RENAL FAILURE. SEX IS A KNOWN CONTRIBUTOR TO THE DIFFERENCES IN INCIDENCE AND PROGRESSION OF CKD. EPIGENETIC PROGRAMMING IS AN ESSENTIAL REGULATOR OF RENAL PHYSIOLOGY AND IS CRITICALLY INVOLVED IN THE PATHOPHYSIOLOGY OF RENAL INJURY AND FIBROSIS. EPIGENETIC SIGNALING INTEGRATES INTRINSIC AND EXTRINSIC SIGNALS ONTO THE GENOME, AND VARIOUS ENVIRONMENTAL AND HORMONAL STIMULI, INCLUDING SEX HORMONES, WHICH REGULATE GENE EXPRESSION AND DOWNSTREAM CELLULAR RESPONSES. THE MOST EXTENSIVELY STUDIED EPIGENETIC ALTERATIONS THAT PLAY A CRITICAL ROLE IN RENAL DAMAGE INCLUDE HISTONE MODIFICATIONS AND DNA METHYLATION. NOTABLY, THESE EPIGENETIC ALTERATIONS ARE REVERSIBLE, MAKING THEM CANDIDATES FOR POTENTIAL THERAPEUTIC TARGETS FOR THE TREATMENT OF RENAL DISEASES. HERE, WE WILL SUMMARIZE THE CURRENT KNOWLEDGE ON SEX-DIFFERENCES IN EPIGENETIC MODULATION OF RENAL FIBROSIS AND INFLAMMATION AND HIGHLIGHT SOME POSSIBLE EPIGENETIC THERAPEUTIC STRATEGIES FOR CKD TREATMENT. 2023 5 4668 35 NEW INSIGHTS INTO MOLECULAR MECHANISMS OF EPIGENETIC REGULATION IN KIDNEY DISEASE. THE NUMBER OF PATIENTS WITH KIDNEY FAILURE HAS INCREASED IN RECENT YEARS. DIFFERENT FACTORS CONTRIBUTE TO THE PROGRESSION OF CHRONIC KIDNEY DISEASE, INCLUDING GLOMERULAR SCLEROSIS, ATHEROSCLEROSIS OF THE RENAL ARTERIES AND TUBULOINTERSTITIAL FIBROSIS. TUBULOINTERSTITIAL INJURY IS INDUCED BY HYPOXIA AND OTHER INFLAMMATORY SIGNALS, LEADING TO FIBROBLAST ACTIVATION. TECHNOLOGICAL ADVANCES USING HIGH-THROUGHPUT SEQUENCING HAS ENABLED THE DETERMINATION OF THE EXPRESSION PROFILE OF ALMOST ALL GENES, REVEALING THAT GENE EXPRESSION IS INTRICATELY REGULATED BY DNA METHYLATION, HISTONE MODIFICATION, CHANGES IN CHROMOSOME CONFORMATION, LONG NON-CODING RNAS AND MICRORNAS. THESE EPIGENETIC MODIFICATIONS ARE STORED AS CELLULAR EPIGENETIC MEMORY. EPIGENETIC MEMORY LEADS TO ADULT-ONSET DISEASE OR AGEING IN THE LONG TERM AND MAY POSSIBLY PLAY AN IMPORTANT ROLE IN THE KIDNEY DISEASE PROCESS. HEREIN WE EMPHASIZE THE IMPORTANCE OF CLARIFYING THE MOLECULAR MECHANISMS UNDERLYING EPIGENETIC MODIFICATIONS BECAUSE THIS MAY LEAD TO THE DEVELOPMENT OF NEW THERAPEUTIC TARGETS IN KIDNEY DISEASE. 2016 6 4463 28 MOLECULAR MECHANISMS OF HISTONE DEACETYLASES AND INHIBITORS IN RENAL FIBROSIS PROGRESSION. RENAL FIBROSIS IS A COMMON PROGRESSIVE MANIFESTATION OF CHRONIC KIDNEY DISEASE. THIS PHENOMENON OF SELF-REPAIR IN RESPONSE TO KIDNEY DAMAGE SERIOUSLY AFFECTS THE NORMAL FILTRATION FUNCTION OF THE KIDNEY. YET, THERE ARE NO SPECIFIC TREATMENTS FOR THE CONDITION, WHICH MARKS FIBROSIS AS AN IRREVERSIBLE PATHOLOGICAL SEQUELA. AS SUCH, THERE IS A PRESSING NEED TO IMPROVE OUR UNDERSTANDING OF HOW FIBROSIS DEVELOPS AT THE CELLULAR AND MOLECULAR LEVELS AND EXPLORE SPECIFIC TARGETED THERAPIES FOR THESE PATHOGENIC MECHANISMS. IT IS NOW GENERALLY ACCEPTED THAT RENAL FIBROSIS IS A PATHOLOGICAL TRANSITION MEDIATED BY EXTRACELLULAR MATRIX (ECM) DEPOSITION, ABNORMAL ACTIVATION OF MYOFIBROBLASTS, AND EPITHELIAL-MESENCHYMAL TRANSITION (EMT) OF RENAL TUBULAR EPITHELIAL CELLS UNDER THE REGULATION OF TGF-BETA. HISTONE DEACETYLASES (HDACS) APPEAR TO PLAY AN ESSENTIAL ROLE IN PROMOTING RENAL FIBROSIS THROUGH NON-HISTONE EPIGENETIC MODIFICATIONS. IN THIS REVIEW, WE SUMMARIZE THE MECHANISMS OF RENAL FIBROSIS AND THE SIGNALING PATHWAYS THAT MIGHT BE INVOLVED IN HDACS IN RENAL FIBROSIS, AND THE SPECIFIC MECHANISMS OF ACTION OF VARIOUS HDAC INHIBITORS (HDACI) IN THE ANTI-FIBROTIC PROCESS TO ELUCIDATE HDACI AS A NOVEL THERAPEUTIC TOOL TO SLOW DOWN THE PROGRESSION OF RENAL FIBROSIS. 2022 7 2542 35 EPIGENETICS IN KIDNEY DISEASES. EPIGENETICS EXAMINES HERITABLE CHANGES IN DNA AND ITS ASSOCIATED PROTEINS EXCEPT MUTATIONS IN GENE SEQUENCE. EPIGENETIC REGULATION PLAYS FUNDAMENTAL ROLES IN KIDNEY CELL BIOLOGY THROUGH THE ACTION OF DNA METHYLATION, CHROMATIN MODIFICATION VIA EPIGENETIC REGULATORS AND NON-CODING RNA SPECIES. KIDNEY DISEASES, INCLUDING ACUTE KIDNEY INJURY, CHRONIC KIDNEY DISEASE, DIABETIC KIDNEY DISEASE AND RENAL FIBROSIS ARE MULTISTEP PROCESSES ASSOCIATED WITH NUMEROUS MOLECULAR ALTERATIONS EVEN IN INDIVIDUAL KIDNEY CELLS. EPIGENETIC ALTERATIONS, INCLUDING ANOMALOUS DNA METHYLATION, ABERRANT HISTONE ALTERATIONS AND CHANGES OF MICRORNA EXPRESSION ALL CONTRIBUTE TO KIDNEY PATHOGENESIS. THESE CHANGES ALTER THE GENOME-WIDE EPIGENETIC SIGNATURES AND DISRUPT ESSENTIAL PATHWAYS THAT PROTECT RENAL CELLS FROM UNCONTROLLED GROWTH, APOPTOSIS AND DEVELOPMENT OF OTHER RENAL ASSOCIATED SYNDROMES. MOLECULAR CHANGES IMPACT CELLULAR FUNCTION WITHIN KIDNEY CELLS AND ITS MICROENVIRONMENT TO DRIVE AND MAINTAIN DISEASE PHENOTYPE. IN THIS CHAPTER, WE BRIEFLY SUMMARIZE EPIGENETIC MECHANISMS IN FOUR KIDNEY DISEASES INCLUDING ACUTE KIDNEY INJURY, CHRONIC KIDNEY DISEASE, DIABETIC KIDNEY DISEASE AND RENAL FIBROSIS. WE PRIMARILY FOCUS ON CURRENT KNOWLEDGE ABOUT THE GENOME-WIDE PROFILING OF DNA METHYLATION AND HISTONE MODIFICATION, AND EPIGENETIC REGULATION ON SPECIFIC GENE(S) IN THE PATHOPHYSIOLOGY OF THESE DISEASES AND THE TRANSLATIONAL POTENTIAL OF IDENTIFYING NEW BIOMARKERS AND TREATMENT FOR PREVENTION AND THERAPY. INCORPORATING EPIGENOMIC TESTING INTO CLINICAL RESEARCH IS ESSENTIAL TO ELUCIDATE NOVEL EPIGENETIC BIOMARKERS AND DEVELOP PRECISION MEDICINE USING EMERGING THERAPIES. 2021 8 5950 35 TARGETING THE PROGRESSION OF CHRONIC KIDNEY DISEASE. CHRONIC KIDNEY DISEASE (CKD) IS A DEVASTATING CONDITION THAT IS REACHING EPIDEMIC LEVELS OWING TO THE INCREASING PREVALENCE OF DIABETES MELLITUS, HYPERTENSION AND OBESITY, AS WELL AS AGEING OF THE POPULATION. REGARDLESS OF THE UNDERLYING AETIOLOGY, CKD IS SLOWLY PROGRESSIVE AND LEADS TO IRREVERSIBLE NEPHRON LOSS, END-STAGE RENAL DISEASE AND/OR PREMATURE DEATH. FACTORS THAT CONTRIBUTE TO CKD PROGRESSION INCLUDE PARENCHYMAL CELL LOSS, CHRONIC INFLAMMATION, FIBROSIS AND REDUCED REGENERATIVE CAPACITY OF THE KIDNEY. CURRENT THERAPIES HAVE LIMITED EFFECTIVENESS AND ONLY DELAY DISEASE PROGRESSION, UNDERSCORING THE NEED TO DEVELOP NOVEL THERAPEUTIC APPROACHES TO EITHER STOP OR REVERSE PROGRESSION. PRECLINICAL STUDIES HAVE IDENTIFIED SEVERAL APPROACHES THAT REDUCE FIBROSIS IN EXPERIMENTAL MODELS, INCLUDING TARGETING CYTOKINES, TRANSCRIPTION FACTORS, DEVELOPMENTAL AND SIGNALLING PATHWAYS AND EPIGENETIC MODULATORS, PARTICULARLY MICRORNAS. SOME OF THESE NEPHROPROTECTIVE STRATEGIES ARE NOW BEING TESTED IN CLINICAL TRIALS. LESSONS LEARNED FROM THE FAILURE OF CLINICAL STUDIES OF TRANSFORMING GROWTH FACTOR BETA1 (TGFBETA1) BLOCKADE UNDERSCORE THE NEED FOR ALTERNATIVE APPROACHES TO CKD THERAPY, AS STRATEGIES THAT TARGET A SINGLE PATHOGENIC PROCESS MAY RESULT IN UNEXPECTED NEGATIVE EFFECTS ON SIMULTANEOUSLY OCCURRING PROCESSES. ADDITIONAL PROMISING AVENUES INCLUDE PREVENTING TUBULAR CELL INJURY AND ANTI-FIBROTIC THERAPIES THAT TARGET ACTIVATED MYOFIBROBLASTS, THE MAIN COLLAGEN-PRODUCING CELLS. 2020 9 2286 30 EPIGENETIC REGULATION IN KIDNEY TRANSPLANTATION. KIDNEY TRANSPLANTATION IS A STANDARD CARE FOR END STAGE RENAL DISEASE, BUT IT IS ALSO ASSOCIATED WITH A COMPLEX PATHOGENESIS INCLUDING ISCHEMIA-REPERFUSION INJURY, INFLAMMATION, AND DEVELOPMENT OF FIBROSIS. OVER THE PAST DECADE, ACCUMULATING EVIDENCE HAS SUGGESTED A ROLE OF EPIGENETIC REGULATION IN KIDNEY TRANSPLANTATION, INVOLVING DNA METHYLATION, HISTONE MODIFICATION, AND VARIOUS KINDS OF NON-CODING RNAS. HERE, WE ANALYZE THESE RECENT STUDIES SUPPORTING THE ROLE OF EPIGENETIC REGULATION IN DIFFERENT PATHOLOGICAL PROCESSES OF KIDNEY TRANSPLANTATION, I.E., ISCHEMIA-REPERFUSION INJURY, ACUTE REJECTION, AND CHRONIC GRAFT PATHOLOGIES INCLUDING RENAL INTERSTITIAL FIBROSIS. FURTHER INVESTIGATION OF EPIGENETIC ALTERATIONS, THEIR PATHOLOGICAL ROLES AND UNDERLYING MECHANISMS IN KIDNEY TRANSPLANTATION MAY LEAD TO NEW STRATEGIES FOR THE DISCOVERY OF NOVEL DIAGNOSTIC BIOMARKERS AND THERAPEUTIC INTERVENTIONS. 2022 10 3349 33 HISTONE DEACETYLASES TAKE CENTER STAGE ON REGULATION OF PODOCYTE FUNCTION. BACKGROUND: PODOCYTES (HIGHLY SPECIALIZED AND TERMINALLY DIFFERENTIATED EPITHELIAL CELLS) ARE INTEGRAL COMPONENTS OF THE GLOMERULAR FILTRATION BARRIER THAT ARE VULNERABLE TO A VARIETY OF INJURIES AND, AS A RESULT, THEY UNDERGO A SERIES OF CHANGES RANGING FROM HYPERTROPHY TO DETACHMENT AND APOPTOSIS. PODOCYTE INJURY IS A MAJOR DETERMINANT IN PROTEINURIC KIDNEY DISEASE AND IDENTIFICATION OF POTENTIAL THERAPEUTIC TARGETS FOR PREVENTING PODOCYTE INJURY HAS CLINICAL IMPORTANCE. ALTHOUGH NUMEROUS STUDIES HAVE ACHIEVED DRAMATIC ADVANCES IN THE UNDERSTANDING OF PODOCYTE BIOLOGY AND ITS RELEVANCE TO RENAL INJURY, FEW EFFECTIVE AND SPECIFIC THERAPIES ARE AVAILABLE. SUMMARY: EPIGENETIC MODIFICATIONS HAVE BEEN PROVEN TO PLAY IMPORTANT ROLES IN THE PATHOGENESIS OF KIDNEY DISEASES. AMONG THEM, HISTONE DEACETYLASE (HDAC)-MEDIATED EPIGENETIC ACETYLATION IN THE KIDNEY HAS ATTRACTED MUCH ATTENTION, WHICH MAY PLAY MULTIPLE ROLES IN BOTH KIDNEY DEVELOPMENT AND THE PATHOGENESIS OF KIDNEY DISEASE. RECENT STUDIES HAVE DEMONSTRATED THAT HDAC PROTECT AGAINST PODOCYTE INJURY BY REGULATION OF INFLAMMATION, APOPTOSIS, AUTOPHAGY, MITOCHONDRIAL FUNCTION, AND INSULIN RESISTANCE. IN THIS REVIEW, WE SUMMARIZE RECENT ADVANCES IN THE UNDERSTANDING OF THE FUNCTIONS AND REGULATORY MECHANISMS OF HDAC IN PODOCYTES AND ASSOCIATED PROTEINURIC KIDNEY DISEASES. IN ADDITION, WE PROVIDE EVIDENCE OF THE POTENTIAL THERAPEUTIC EFFECTS OF HDAC INHIBITORS FOR PROTEINURIC KIDNEY DISEASE. KEY MESSAGES: PHARMACOLOGICAL TARGETING OF HDAC-MEDIATED EPIGENETIC PROCESSES MAY OPEN NEW THERAPEUTIC AVENUES FOR CHRONIC KIDNEY DISEASE. 2020 11 3326 36 HISTONE DEACETYLASE 3 (HDAC3) AS AN IMPORTANT EPIGENETIC REGULATOR OF KIDNEY DISEASES. DEVELOPMENT AND PROGRESSION OF MANY KIDNEY DISEASES ARE SUBSTANTIALLY INFLUENCED BY ABERRANT PROTEIN ACETYLATION MODIFICATIONS OF GENE EXPRESSION CRUCIAL FOR KIDNEY FUNCTIONS. HISTONE DEACETYLASE (HDAC) EXPRESSION ALTERATIONS ARE DETECTED FROM RENAL SAMPLES OF PATIENTS AND ANIMAL MODELS OF VARIOUS KIDNEY DISEASES, AND THE ADMINISTRATIONS OF HDAC INHIBITORS DISPLAY IMPRESSIVE RENAL PROTECTIVE EFFECTS IN VITRO AND IN VIVO. HOWEVER, WHEN THE EXPRESSION ALTERATIONS OF MULTIPLE HDACS OCCUR, NOT ALL THE HDACS CAUSALLY AFFECT THE DISEASE ONSET OR PROGRESSION. IDENTIFICATION OF A SINGLE HDAC AS A DISEASE-CAUSING FACTOR WILL ALLOW SUBTYPE-TARGETED INTERVENTION WITH LESS SIDE EFFECT. HDAC3 IS A UNIQUE HDAC WITH DISTINCT STRUCTURAL AND SUBCELLULAR DISTRIBUTION FEATURES AND CO-REPRESSOR DEPENDENCY. HDAC3 IS REQUIRED FOR KIDNEY DEVELOPMENT AND ITS ABERRATIONS ACTIVELY PARTICIPATE IN MANY PATHOLOGICAL PROCESSES, SUCH AS CANCER, CARDIOVASCULAR DISEASES, DIABETES, AND NEURODEGENERATIVE DISORDERS, AND CONTRIBUTE SIGNIFICANTLY TO THE PATHOGENESIS OF KIDNEY DISEASES. THIS REVIEW WILL DISCUSS THE RECENT STUDIES THAT INVESTIGATE THE CRITICAL ROLES OF HDAC3 ABERRATIONS IN KIDNEY DEVELOPMENT, RENAL AGING, RENAL CELL CARCINOMA, RENAL FIBROSIS, CHRONIC KIDNEY DISEASE, POLYCYSTIC KIDNEY DISEASE, GLOMERULAR PODOCYTE INJURY, AND DIABETIC NEPHROPATHY. THESE STUDIES REVEAL THE DISTINCT CHARACTERS OF HDAC3 ABERRATIONS THAT ACT ON DIFFERENT MOLECULES/SIGNALING PATHWAYS UNDER VARIOUS RENAL PATHOLOGICAL CONDITIONS, WHICH MIGHT SHED LIGHTS INTO THE EPIGENETIC MECHANISMS OF RENAL DISEASES AND THE POTENTIALLY THERAPEUTIC STRATEGIES. 2022 12 6409 29 THE SIGNALING OF CELLULAR SENESCENCE IN DIABETIC NEPHROPATHY. DIABETIC NEPHROPATHY IS THE LEADING CAUSE OF CHRONIC KIDNEY DISEASE (CKD) IN WESTERN COUNTRIES. NOTABLY, IT HAS A RAPIDLY RISING PREVALENCE IN CHINA. THE PATIENTS, COMMONLY COMPLICATED WITH CARDIOVASCULAR DISEASES AND NEUROLOGIC DISORDERS, ARE AT HIGH RISK TO PROGRESS INTO END-STAGE RENAL DISEASE (ESRD) AND DEATH. HOWEVER, THE PATHOGENIC MECHANISMS OF DIABETIC NEPHROPATHY HAVE NOT BEEN DETERMINED. CELLULAR SENESCENCE, WHICH RECENTLY HAS GAINED BROAD ATTENTION, IS THOUGHT TO BE AN IMPORTANT PLAYER IN THE ONSET AND DEVELOPMENT OF DIABETIC NEPHROPATHY. IN THIS ISSUE, WE GENERALLY REVIEW THE MECHANISMS OF CELLULAR SENESCENCE IN DIABETIC NEPHROPATHY, WHICH INVOLVE TELOMERE ATTRITION, DNA DAMAGE, EPIGENETIC ALTERATIONS, MITOCHONDRIAL DYSFUNCTION, LOSS OF KLOTHO, WNT/BETA-CATENIN SIGNALING ACTIVATION, PERSISTENT INFLAMMATION, AND ACCUMULATION OF UREMIC TOXINS. MOREOVER, WE HIGHLIGHT THE POTENTIAL THERAPEUTIC TARGETS OF CELLULAR SENESCENCE IN DIABETIC NEPHROPATHY AND PROVIDE IMPORTANT CLUES FOR CLINICAL STRATEGIES. 2019 13 1880 34 EMERGING STRATEGIES TO DISRUPT THE CENTRAL TGF-BETA AXIS IN KIDNEY FIBROSIS. CHRONIC KIDNEY DISEASE (CKD) AFFECTS MORE THAN 20 MILLION PEOPLE IN THE UNITED STATES AND THE GLOBAL BURDEN OF THIS DISORDER IS INCREASING. MANY AFFECTED INDIVIDUALS WILL PROGRESS TO END STAGE KIDNEY DISEASE NECESSITATING DIALYSIS OR TRANSPLANTATION. CKD IS ALSO A MAJOR INDEPENDENT CONTRIBUTOR TO THE RISK OF CARDIOVASCULAR MORBIDITY AND MORTALITY. TUBULOINTERSTITIAL FIBROSIS IS A FINAL COMMON PATHWAY FOR MOST CAUSES OF PROGRESSIVE CKD. CURRENTLY, THERE ARE NO CLINICALLY AVAILABLE THERAPIES TARGETING FIBROSIS THAT CAN SLOW THE DECLINE IN KIDNEY FUNCTION. ALTHOUGH IT HAS LONG BEEN KNOWN THAT TGF-BETA SIGNALING IS A CRITICAL MEDIATOR OF KIDNEY FIBROSIS, TRANSLATING THIS KNOWLEDGE TO THE CLINIC HAS BEEN CHALLENGING. IN THIS REVIEW, WE HIGHLIGHT SOME RECENT INSIGHTS INTO THE MECHANISMS OF TGF-BETA SIGNALING THAT TARGET ACTIVATION OF THIS CYTOKINE AT THE SITE OF INJURY OR SELECTIVELY INHIBIT PRO-FIBROTIC GENE EXPRESSION. MOLECULES DIRECTED AT THESE TARGETS HOLD THE PROMISE OF ATTAINING THERAPEUTIC EFFICACY WHILE LIMITING TOXICITY SEEN WITH GLOBAL INHIBITION OF TGF-BETA. KIDNEY INJURY HAS PROFOUND EPIGENETIC EFFECTS LEADING TO ALTERED EXPRESSION OF MORE THAN A THOUSAND GENES. WE DISCUSS HOW DRUGS TARGETING EPIGENETIC MODIFICATIONS, SOME OF WHICH ARE IN USE FOR CANCER THERAPY, HAVE THE POTENTIAL TO REPROGRAM GENE REGULATORY NETWORKS TO FAVOR ADAPTIVE REPAIR AND PREVENT FIBROSIS. THE LACK OF RELIABLE BIOMARKERS OF KIDNEY FIBROSIS IS A MAJOR LIMITATION IN DESIGNING CLINICAL TRIALS FOR TESTING CKD TREATMENTS. WE CONCLUDE BY REVIEWING RECENT ADVANCES IN FIBROSIS BIOMARKER DEVELOPMENT. 2019 14 5988 27 TGF-BETA/SMAD AND RENAL FIBROSIS. RENAL FIBROSIS IS CHARACTERIZED BY EXCESSIVE DEPOSITION OF EXTRACELLULAR MATRIX (ECM) THAT DISRUPTS AND REPLACES FUNCTIONAL PARENCHYMA, WHICH LEADS TO ORGAN FAILURE. IT IS KNOWN AS THE MAJOR PATHOLOGICAL MECHANISM OF CHRONIC KIDNEY DISEASE (CKD). ALTHOUGH CKD HAS AN IMPACT ON NO LESS THAN 10% OF THE WORLD POPULATION, THERAPEUTIC OPTIONS ARE STILL LIMITED. REGARDLESS OF ETIOLOGY, ELEVATED TGF-BETA LEVELS ARE HIGHLY CORRELATED WITH THE ACTIVATED PRO-FIBROTIC PATHWAYS AND DISEASE PROGRESSION. TGF-BETA, THE KEY DRIVER OF RENAL FIBROSIS, IS INVOLVED IN A DYNAMIC PATHOPHYSIOLOGICAL PROCESS THAT LEADS TO CKD AND END-STAGE RENAL DISEASE (ESRD). IT IS BECOMING CLEAR THAT EPIGENETICS REGULATES RENAL PROGRAMMING, AND THEREFORE, THE DEVELOPMENT AND PROGRESSION OF RENAL DISEASE. INDEED, RECENT EVIDENCE SHOWS TGF-BETA1/SMAD SIGNALING REGULATES RENAL FIBROSIS VIA EPIGENETIC-CORRELATED MECHANISMS. THIS REVIEW FOCUSES ON THE FUNCTION OF TGF-BETA/SMADS IN RENAL FIBROGENESIS, AND THE ROLE OF EPIGENETICS AS A REGULATOR OF PRO-FIBROTIC GENE EXPRESSION. 2019 15 1487 28 DNA DAMAGE AND EPIGENETIC CHANGES IN KIDNEY DISEASES - FOCUSED ON TRANSCRIPTION FACTORS IN PODOCYTES. RECENTLY IT HAS BEEN SHOWN THAT EPIGENETIC MECHANISMS ARE INVOLVED IN INITIATION AND PROGRESSION OF CARIDIOVASCULAR AND METABOLIC DISEASES, INCLUDING DIABETES, OBESITY, ATHEROSCLEROSIS, HEART FAILURE, HYPERTENSION AND KIDNEY DISEASES. IN THESE CHRONIC DISEASES, VARIOUS EXOGENOUS AND ENDOGENOUS STRESSES CAUSE DNA DAMAGE, FOLLOWED BY DNA REPAIR PROCESS. ACCUMULATION OF DNA DAMAGES AND IMPAIRED REPAIR PROCESS CAN LEAD TO EPIGENETIC CHANGES, WHICH MAY CONTRIBUTE TO ONSET AND PROGRESSION OF DISEASES. RECENTLY WE HAVE SHOWN THAT THERAPEUTIC EFFECT OF TRANSCRIPTION FACTOR KLF4 (KRUPPEL-LIKE FACTOR 4) IN KIDNEY GLOMERULAR EPITHELIAL CELLS (PODOCYTES) ON PROTEINURIC KIDNEY DISEASES THROUGH EPIGENETIC MECHANISMS. OUR RESULT SUGGESTS THE POSSIBILITY OF TRANSCRIPTION FACTORS AS A TARGET OF SELECTIVE EPIGENETIC THERAPY. MOREOVER, WE HAVE REPORTED THAT RENIN-ANGIOTENSIN SYSTEM (RAS) BLOCKERS, WHICH ARE WIDELY PRESCRIBED FOR THE TREATMENT OF CARDIOVASCULAR DISEASES, CAN RESTORE EPIGENETIC CHANGES THROUGH KLF4 IN PART. THESE RESULTS SUGGEST THAT ACTIVATION OF RAS CAUSES EPIGENETIC CHANGES IN DISEASE STATES, AND ELUCIDATION OF THE PRECISE MECHANISM MAY LEAD TO ESTABLISHMENT OF NOVEL THERAPEUTIC TARGET OF KIDNEY DISEASES. IN THIS REVIEW WE FOCUS ON DNA DAMAGE REPAIR SYSTEM AND EPIGENETIC MODULATORS IN DISEASE STATES, AND SPECULATE A CANDIDATE FOR EPIGENETIC THERAPY OF KIDNEY DISEASES. 2016 16 2211 26 EPIGENETIC MODIFICATIONS AND THE DEVELOPMENT OF KIDNEY GRAFT FIBROSIS. PURPOSE OF REVIEW: TO OUTLINE RECENT DISCOVERIES IN EPIGENETIC REGULATORY MECHANISMS THAT HAVE POTENTIAL IMPLICATIONS IN THE DEVELOPMENT OF RENAL FIBROSIS FOLLOWING KIDNEY TRANSPLANTATION. RECENT FINDINGS: THE CHARACTERIZATION OF RENAL FIBROSIS FOLLOWING KIDNEY TRANSPLANTATION HAS SHOWN TGFBETA/SMAD SIGNALING TO PLAY A MAJOR ROLE IN THE PROGRESSION TO CHRONIC ALLOGRAFT DYSFUNCTION. THE ONSET OF UNREGULATED PROINFLAMMATORY PATHWAYS ARE ONLY EXACERBATED BY THE DECLINE IN REGULATORY MECHANISMS LOST WITH PROGRESSIVE PATIENT AGE AND COMORBIDITIES SUCH AS HYPERTENSION AND DIABETES. HOWEVER, SIGNIFICANT DEVELOPMENTS IN THE RECOGNITION OF EPIGENETIC REGULATORY MARKERS UPSTREAM OF ABERRANT TGFBETA-SIGNALING HAS SIGNIFICANT CLINICAL POTENTIAL TO PROVIDE THERAPEUTIC TARGETS FOR THE TREATMENT OF RENAL FIBROSIS. IN ADDITION, DISCOVERIES IN EXTRACELLULAR VESICLES AND THE CHARACTERIZATION OF THEIR CARGO HAS LAID NEW FRAMEWORK FOR THE POTENTIAL TO EVALUATE PATIENT OUTCOMES INDEPENDENT OF INVASIVE BIOPSIES. SUMMARY: THE CURRENT REVIEW SUMMARIZES THE MAIN FINDINGS IN EPIGENETIC MACHINERY SPECIFIC TO THE DEVELOPMENT OF RENAL FIBROSIS AND HIGHLIGHTS THERAPEUTIC OPTIONS THAT HAVE SIGNIFICANT POTENTIAL TO TRANSLATE INTO CLINICAL PRACTICE. 2021 17 3826 39 INVESTIGATION OF EPIGENETICS IN KIDNEY CELL BIOLOGY. EPIGENETICS IS THE STUDY OF HERITABLE CHANGES IN DNA OR ITS ASSOCIATED PROTEINS EXCEPT MUTATIONS IN GENE SEQUENCE. EPIGENETIC REGULATION PLAYS FUNDAMENTAL ROLES IN THE PROCESSES OF KIDNEY CELL BIOLOGY THROUGH THE ACTION OF DNA METHYLATION, CHROMATIN MODIFICATIONS VIA EPIGENETIC REGULATORS AND INTERACTION VIA TRANSCRIPTION FACTORS, AND NONCODING RNA SPECIES. KIDNEY DISEASES, INCLUDING ACUTE KIDNEY INJURY, CHRONIC KIDNEY DISEASE, NEPHRITIC AND NEPHROTIC SYNDROMES, PYELONEPHRITIS AND POLYCYSTIC KIDNEY DISEASES ARE DRIVEN BY ABERRANT ACTIVITY IN NUMEROUS SIGNALING PATHWAYS IN EVEN INDIVIDUAL KIDNEY CELL. EPIGENETIC ALTERATIONS, INCLUDING DNA METHYLATION, HISTONE ACETYLATION AND METHYLATION, NONCODING RNAS, AND PROTEIN POSTTRANSLATIONAL MODIFICATIONS, COULD DISRUPT ESSENTIAL PATHWAYS THAT PROTECT THE RENAL CELLS FROM UNCONTROLLED GROWTH, APOPTOSIS AND ESTABLISHMENT OF OTHER RENAL ASSOCIATED SYNDROMES, WHICH HAVE BEEN RECOGNIZED AS ONE OF THE CRITICAL MECHANISMS FOR REGULATING FUNCTIONAL CHANGES THAT DRIVE AND MAINTAIN THE KIDNEY DISEASE PHENOTYPE. IN THIS CHAPTER, WE BRIEFLY SUMMARIZE THE EPIGENETIC MECHANISMS IN KIDNEY CELL BIOLOGY AND EPIGENETIC BASIS OF KIDNEY DEVELOPMENT, AND INTRODUCE EPIGENETIC TECHNIQUES THAT CAN BE USED IN INVESTIGATING THE MOLECULAR MECHANISM OF KIDNEY CELL BIOLOGY AND KIDNEYS DISEASES, PRIMARILY FOCUSING ON THE INTEGRATION OF DNA METHYLATION AND CHROMATIN IMMUNOPRECIPITATION TECHNOLOGIES INTO KIDNEY DISEASE ASSOCIATED STUDIES. FUTURE STUDIES USING THESE EMERGING TECHNOLOGIES WILL ELUCIDATE HOW ALTERATIONS IN THE RENAL CELL EPIGENOME COOPERATE WITH GENETIC ABERRATIONS FOR KIDNEY DISEASE INITIATION AND PROGRESSION. INCORPORATING EPIGENOMIC TESTING INTO THE CLINICAL RESEARCH IS ESSENTIAL TO FUTURE STUDIES WITH EPIGENETICS BIOMARKERS AND PRECISION MEDICINE USING EMERGING EPIGENETIC THERAPIES. 2019 18 3640 23 INCREASED EXTRACELLULAR MATRIX PROTEIN PRODUCTION IN CHRONIC DIABETIC COMPLICATIONS: IMPLICATIONS OF NON-CODING RNAS. MANAGEMENT OF CHRONIC DIABETIC COMPLICATIONS REMAINS A MAJOR MEDICAL CHALLENGE WORLDWIDE. ONE OF THE CHARACTERISTIC FEATURES OF ALL CHRONIC DIABETIC COMPLICATIONS IS AUGMENTED PRODUCTION OF EXTRACELLULAR MATRIX (ECM) PROTEINS. SUCH ECM PROTEINS ARE DEPOSITED IN ALL TISSUES AFFECTED BY CHRONIC COMPLICATIONS, ULTIMATELY CAUSING ORGAN DAMAGE AND DYSFUNCTION. A CONTRIBUTING FACTOR TO THIS PATHOGENETIC PROCESS IS GLUCOSE-INDUCED ENDOTHELIAL DAMAGE, WHICH INVOLVES PHENOTYPIC TRANSFORMATION OF ENDOTHELIAL CELLS (ECS). THIS PHENOTYPIC TRANSITION OF ECS, FROM A QUIESCENT STATE TO AN ACTIVATED DYSFUNCTIONAL STATE, CAN BE MEDIATED THROUGH ALTERATIONS IN THE SYNTHESIS OF CELLULAR PROTEINS. IN THIS REVIEW, WE DISCUSSED THE ROLES OF NON-CODING RNAS, SPECIFICALLY MICRORNAS (MIRNAS) AND LONG NON-CODING RNAS (LNCRNAS), IN SUCH PROCESSES. WE FURTHER OUTLINED OTHER EPIGENETIC MECHANISMS REGULATING THE BIOGENESIS AND/OR FUNCTION OF NON-CODING RNAS. OVERALL, WE BELIEVE THAT BETTER UNDERSTANDING OF SUCH MOLECULAR PROCESSES MAY LEAD TO THE DEVELOPMENT OF NOVEL BIOMARKERS AND THERAPEUTIC STRATEGIES IN THE FUTURE. 2019 19 4336 27 MICRORNAS: THE UNDERLYING MEDIATORS OF PATHOGENETIC PROCESSES IN VASCULAR COMPLICATIONS OF DIABETES. DIABETES MELLITUS CAUSES CHRONIC COMPLICATIONS PRIMARILY AFFECTING THE VASCULATURE OF VARIOUS ORGANS, RISKING PATIENTS FOR RENAL FAILURE, VISION LOSS AND HEART FAILURE. A NEWLY DISCOVERED CLASS OF MOLECULES, MICRORNAS, MAY BE IMPORTANT IN THE GENESIS OF THESE PATHOLOGIC PROCESSES. MICRORNAS REGULATE GENE EXPRESSION AT THE POST-TRANSCRIPTIONAL LEVEL BY INHIBITING TARGET MESSENGER RNA TRANSLATION. IN DISEASE STATES, HOWEVER, THE EXPRESSION OF MICRORNAS OFTEN IS ALTERED, RESULTING IN FURTHER ALTERED EXPRESSION (MOSTLY OVEREXPRESSION) OF DOWNSTREAM TARGET GENES. INTERESTINGLY, RESTORING MICRORNA EXPRESSION TO NORMAL LEVELS CAN CORRECT DOWNSTREAM EFFECTS AND PREVENT DIABETES-ASSOCIATED CHANGES. INVESTIGATIONS INTO MICRORNA INVOLVED IN VARIOUS PATHOGENETIC PROCESSES MEDIATING DIABETIC NEPHROPATHY, RETINOPATHY AND CARDIOMYOPATHY ARE HIGHLIGHTED IN THIS REVIEW. FUTURE DIRECTIONS OF MICRORNA IN THERAPEUTICS AND DIAGNOSTICS ARE ALSO DISCUSSED. IT IS OUR INTENT TO HELP THE READER APPRECIATE THE DIVERSE INTERACTIONS MICRORNAS HAVE IN CELLULAR SIGNALLING AND HOW UNDERSTANDING EPIGENETIC ELEMENTS, SUCH AS MICRORNAS, POTENTIALLY CAN YIELD NEW THERAPEUTIC STRATEGIES. 2013 20 1597 32 DNA METHYLATION REGULATED GENE EXPRESSION IN ORGAN FIBROSIS. DNA METHYLATION IS A MAJOR EPIGENETIC MECHANISM TO REGULATE GENE EXPRESSION. EPIGENETIC REGULATION, INCLUDING DNA METHYLATION, HISTONE MODIFICATIONS AND RNA INTERFERENCE, RESULTS IN HERITABLE CHANGES IN GENE EXPRESSION INDEPENDENT OF ALTERATIONS IN DNA SEQUENCE. EPIGENETIC REGULATION OFTEN OCCURS IN RESPONSE TO AGING AND ENVIRONMENT STIMULI, INCLUDING EXPOSURES AND DIET. STUDIES HAVE SHOWN THAT DNA METHYLATION IS CRITICAL IN THE PATHOGENESIS OF FIBROSIS INVOLVING MULTIPLE ORGAN SYSTEMS, CONTRIBUTING TO SIGNIFICANT MORBIDITY AND MORTALITY. ABERRANT DNA METHYLATION CAN SILENCE OR ACTIVATE GENE EXPRESSION PATTERNS THAT DRIVE THE FIBROSIS PROCESS. FIBROSIS IS A PATHOLOGICAL WOUND HEALING PROCESS IN RESPONSE TO CHRONIC INJURY. IT IS CHARACTERIZED BY EXCESSIVE EXTRACELLULAR MATRIX PRODUCTION AND ACCUMULATION, WHICH EVENTUALLY AFFECTS ORGAN ARCHITECTURE AND RESULTS IN ORGAN FAILURE. FIBROSIS CAN AFFECT A WIDE RANGE OF ORGANS, INCLUDING THE HEART AND LUNGS, AND HAVE LIMITED THERAPEUTIC OPTIONS. DNA METHYLATION, LIKE OTHER EPIGENETIC PROCESS, IS REVERSIBLE, THEREFORE REGARDED AS ATTRACTIVE THERAPEUTIC INTERVENTIONS. ALTHOUGH EPIGENETIC MECHANISMS ARE HIGHLY INTERACTIVE AND OFTEN REINFORCING, THIS REVIEW DISCUSSES DNA METHYLATION-DEPENDENT MECHANISMS IN THE PATHOGENESIS OF ORGAN FIBROSIS, WITH FOCUS ON CARDIAC AND PULMONARY FIBROSIS. WE DISCUSS SPECIFIC PRO- AND ANTI-FIBROTIC GENES AND PATHWAYS REGULATED BY DNA METHYLATION IN ORGAN FIBROSIS; WE FURTHER HIGHLIGHT THE POTENTIAL BENEFITS AND SIDE-EFFECTS OF EPIGENETIC THERAPIES IN FIBROTIC DISORDERS. 2017