1 2286 81 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 2 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 3 2542 36 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 4 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 5 4668 36 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 3826 34 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 7 5660 31 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 8 1880 31 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 9 2579 23 EPIGENETICS OF KIDNEY DISEASE. DNA METHYLATION AND HISTONE MODIFICATIONS DETERMINE RENAL PROGRAMMING AND THE DEVELOPMENT AND PROGRESSION OF RENAL DISEASE. THE IDENTIFICATION OF THE WAY IN WHICH THE RENAL CELL EPIGENOME IS ALTERED BY ENVIRONMENTAL MODIFIERS DRIVING THE ONSET AND PROGRESSION OF RENAL DISEASES HAS EXTENDED OUR UNDERSTANDING OF THE PATHOPHYSIOLOGY OF KIDNEY DISEASE PROGRESSION. IN THIS REVIEW, WE FOCUS ON CURRENT KNOWLEDGE CONCERNING THE IMPLICATIONS OF EPIGENETIC MODIFICATIONS DURING RENAL DISEASE FROM EARLY DEVELOPMENT TO CHRONIC KIDNEY DISEASE PROGRESSION INCLUDING RENAL FIBROSIS, DIABETIC NEPHROPATHY AND THE TRANSLATIONAL POTENTIAL OF IDENTIFYING NEW BIOMARKERS AND TREATMENTS FOR THE PREVENTION AND THERAPY OF CHRONIC KIDNEY DISEASE AND END-STAGE KIDNEY DISEASE. 2017 10 607 31 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 11 2193 38 EPIGENETIC MODIFICATION DRIVES ACUTE KIDNEY INJURY-TO-CHRONIC KIDNEY DISEASE PROGRESSION. ACUTE KIDNEY INJURY (AKI) IS A COMMON CLINICAL CRITICAL DISEASE. DUE TO ITS HIGH MORBIDITY, INCREASING RISK OF COMPLICATIONS, HIGH MORTALITY RATE, AND HIGH MEDICAL COSTS, IT HAS BECOME A GLOBAL CONCERN FOR HUMAN HEALTH PROBLEMS. INITIALLY, RESEARCHERS BELIEVED THAT KIDNEYS HAVE A STRONG ABILITY TO REGENERATE AND REPAIR, BUT STUDIES OVER THE PAST 20 YEARS HAVE FOUND THAT KIDNEYS DAMAGED BY AKI ARE OFTEN INCOMPLETE OR EVEN UNABLE TO REPAIR. EVEN WHEN SERUM CREATININE RETURNS TO BASELINE LEVELS, RENAL STRUCTURAL DAMAGE PERSISTS FOR A LONG TIME, LEADING TO THE DEVELOPMENT OF CHRONIC KIDNEY DISEASE (CKD). THE MECHANISM OF AKI-TO-CKD TRANSITION HAS NOT BEEN FULLY ELUCIDATED. AS AN IMPORTANT REGULATOR OF GENE EXPRESSION, EPIGENETIC MODIFICATIONS, SUCH AS HISTONE MODIFICATION, DNA METHYLATION, AND NONCODING RNAS, MAY PLAY AN IMPORTANT ROLE IN THIS PROCESS. ALTERATIONS IN EPIGENETIC MODIFICATION ARE INDUCED BY HYPOXIA, THUS PROMOTING THE EXPRESSION OF INFLAMMATORY FACTOR-RELATED GENES AND COLLAGEN SECRETION. THIS REVIEW ELABORATED THE ROLE OF EPIGENETIC MODIFICATIONS IN AKI-TO-CKD PROGRESSION, THE DIAGNOSTIC VALUE OF EPIGENETIC MODIFICATIONS BIOMARKERS IN AKI CHRONIC OUTCOME, AND THE POTENTIAL ROLE OF TARGETING EPIGENETIC MODIFICATIONS IN THE PREVENTION AND TREATMENT OF AKI TO CKD, IN ORDER TO PROVIDE IDEAS FOR THE SUBSEQUENT ESTABLISHMENT OF TARGETED THERAPEUTIC STRATEGIES TO PREVENT THE PROGRESSION OF RENAL TUBULAR-INTERSTITIAL FIBROSIS. 2021 12 6377 31 THE ROLE OF NON-CODING RNAS IN DIABETIC NEPHROPATHY: POTENTIAL APPLICATIONS AS BIOMARKERS FOR DISEASE DEVELOPMENT AND PROGRESSION. DIABETIC NEPHROPATHY, A PROGRESSIVE KIDNEY DISEASE THAT DEVELOPS SECONDARY TO DIABETES, IS THE MAJOR CAUSE OF CHRONIC KIDNEY DISEASE IN DEVELOPED COUNTRIES, AND CONTRIBUTES SIGNIFICANTLY TO INCREASED MORBIDITY AND MORTALITY AMONG INDIVIDUALS WITH DIABETES. ALTHOUGH THE CAUSES OF DIABETIC NEPHROPATHY ARE NOT FULLY UNDERSTOOD, RECENT STUDIES DEMONSTRATE A ROLE FOR EPIGENETIC FACTORS IN THE DEVELOPMENT OF THE DISEASE. FOR EXAMPLE, NON-CODING RNA (NCRNA) MOLECULES, INCLUDING MICRORNAS (MIRNAS), HAVE BEEN SHOWN TO BE FUNCTIONALLY IMPORTANT IN MODULATING RENAL RESPONSE TO HYPERGLYCEMIA AND PROGRESSION OF DIABETIC NEPHROPATHY. CHARACTERIZATION OF MIRNA EXPRESSION IN DIABETIC NEPHROPATHY FROM STUDIES OF ANIMAL MODELS OF DIABETES, AND IN VITRO INVESTIGATIONS USING DIFFERENT TYPES OF KIDNEY CELLS ALSO SUPPORT THIS ROLE. THE GOAL OF THIS REVIEW, THEREFORE, IS TO SUMMARIZE THE CURRENT STATE OF KNOWLEDGE OF SPECIFIC NCRNAS INVOLVED IN THE DEVELOPMENT OF DIABETIC NEPHROPATHY, WITH A FOCUS ON THE POTENTIAL ROLE OF MIRNAS TO SERVE AS SENSITIVE, NON-INVASIVE BIOMARKERS OF KIDNEY DISEASE AND PROGRESSION. NON-CODING RNAS ARE CURRENTLY RECOGNIZED AS POTENTIALLY IMPORTANT REGULATORS OF GENES INVOLVED IN PROCESSES RELATED TO THE DEVELOPMENT OF DIABETIC NEPHROPATHY, AND AS SUCH, REPRESENT VIABLE TARGETS FOR BOTH CLINICAL DIAGNOSTIC STRATEGIES AND THERAPEUTIC INTERVENTION. 2013 13 5258 24 PROGRESSION OF TUBULOINTERSTITIAL FIBROSIS AND THE CHRONIC KIDNEY DISEASE PHENOTYPE - ROLE OF RISK FACTORS AND EPIGENETICS. ALTHOUGH THE KIDNEY HAS CAPACITY TO REPAIR AFTER MILD INJURY, ONGOING OR SEVERE DAMAGE RESULTS IN SCARRING (FIBROSIS) AND AN ASSOCIATED PROGRESSIVE LOSS OF KIDNEY FUNCTION. HOWEVER, DESPITE ITS UNIVERSAL SIGNIFICANCE, EVIDENCE HIGHLIGHTS A POPULATION BASED HETEROGENEITY IN THE TRAJECTORY OF CHRONIC KIDNEY DISEASE (CKD) IN THESE PATIENTS. TO EXPLAIN THE HETEROGENEITY OF THE CKD PHENOTYPE REQUIRES AN UNDERSTANDING OF THE RELEVANT RISK FACTORS FOR FIBROSIS. THESE FACTORS INCLUDE BOTH THE EXTRINSIC NATURE OF INJURY, AND INTRINSIC FACTORS SUCH AS AGE, GENDER, GENETICS, AND PERPETUAL ACTIVATION OF FIBROBLASTS THROUGH PRIMING. IN MANY CASES AN ADDITIONAL LEVEL OF REGULATION IS PROVIDED BY EPIGENETIC MECHANISMS WHICH INTEGRATE THE VARIOUS PRO-FIBROTIC AND ANTI-FIBROTIC TRIGGERS IN FIBROGENESIS. IN THIS REVIEW WE THEREFORE EXAMINE THE VARIOUS MOLECULAR AND STRUCTURAL CHANGES OF FIBROSIS, AND HOW THEY ARE INFLUENCED BY EXTRINSIC AND INTRINSIC FACTORS. OUR AIM IS TO PROVIDE A UNIFYING HYPOTHESIS TO HELP EXPLAIN THE TRANSITION FROM ACUTE TO CKD. 2017 14 5364 37 RECENT ADVANCES IN EPIGENETICS OF AGE-RELATED KIDNEY DISEASES. RENAL AGING HAS ATTRACTED INCREASING ATTENTION IN TODAY'S AGING SOCIETY, AS ELDERLY PEOPLE WITH ADVANCED AGE ARE MORE SUSCEPTIBLE TO VARIOUS KIDNEY DISORDERS SUCH AS ACUTE KIDNEY INJURY (AKI) AND CHRONIC KIDNEY DISEASE (CKD). THERE IS NO CLEAR-CUT UNIVERSAL MECHANISM FOR IDENTIFYING AGE-RELATED KIDNEY DISEASES, AND THEREFORE, THEY POSE A CONSIDERABLE MEDICAL AND PUBLIC HEALTH CHALLENGE. EPIGENETICS REFERS TO THE STUDY OF HERITABLE MODIFICATIONS IN THE REGULATION OF GENE EXPRESSION THAT DO NOT REQUIRE CHANGES IN THE UNDERLYING GENOMIC DNA SEQUENCE. A VARIETY OF EPIGENETIC MODIFIERS SUCH AS HISTONE DEACETYLASES (HDAC) INHIBITORS AND DNA METHYLTRANSFERASE (DNMT) INHIBITORS HAVE BEEN PROPOSED AS POTENTIAL BIOMARKERS AND THERAPEUTIC TARGETS IN NUMEROUS FIELDS INCLUDING CARDIOVASCULAR DISEASES, IMMUNE SYSTEM DISEASE, NERVOUS SYSTEM DISEASES, AND NEOPLASMS. ACCUMULATING EVIDENCE IN RECENT YEARS INDICATES THAT EPIGENETIC MODIFICATIONS HAVE BEEN IMPLICATED IN RENAL AGING. HOWEVER, NO PREVIOUS SYSTEMATIC REVIEW HAS BEEN PERFORMED TO SYSTEMATICALLY GENERALIZE THE RELATIONSHIP BETWEEN EPIGENETICS AND AGE-RELATED KIDNEY DISEASES. IN THIS REVIEW, WE AIM TO SUMMARIZE THE RECENT ADVANCES IN EPIGENETIC MECHANISMS OF AGE-RELATED KIDNEY DISEASES AS WELL AS DISCUSS THE APPLICATION OF EPIGENETIC MODIFIERS AS POTENTIAL BIOMARKERS AND THERAPEUTIC TARGETS IN THE FIELD OF AGE-RELATED KIDNEY DISEASES. IN SUMMARY, THE MAIN TYPES OF EPIGENETIC PROCESSES INCLUDING DNA METHYLATION, HISTONE MODIFICATIONS, NON-CODING RNA (NCRNA) MODULATION HAVE ALL BEEN IMPLICATED IN THE PROGRESSION OF AGE-RELATED KIDNEY DISEASES, AND THERAPEUTIC TARGETING OF THESE PROCESSES WILL YIELD NOVEL THERAPEUTIC STRATEGIES FOR THE PREVENTION AND/OR TREATMENT OF AGE-RELATED KIDNEY DISEASES. 2022 15 2283 25 EPIGENETIC REGULATION IN FIBROSIS PROGRESS. FIBROSIS, A COMMON PROCESS OF CHRONIC INFLAMMATORY DISEASES, IS DEFINED AS A REPAIR RESPONSE DISORDER WHEN ORGANS UNDERGO CONTINUOUS DAMAGE, ULTIMATELY LEADING TO SCAR FORMATION AND FUNCTIONAL FAILURE. AROUND THE WORLD, FIBROTIC DISEASES CAUSE HIGH MORTALITY, UNFORTUNATELY, WITH LIMITED TREATMENT MEANS IN CLINICAL PRACTICE. WITH THE DEVELOPMENT AND APPLICATION OF DEEP SEQUENCING TECHNOLOGY, COMPREHENSIVELY EXPLORING THE EPIGENETIC MECHANISM IN FIBROSIS HAS BEEN ALLOWED. EXTENSIVE REMODELING OF EPIGENETICS CONTROLLING VARIOUS CELLS PHENOTYPE AND MOLECULAR MECHANISMS INVOLVED IN FIBROGENESIS WAS SUBSEQUENTLY VERIFIED. IN THIS REVIEW, WE SUMMARIZE THE REGULATORY MECHANISMS OF DNA METHYLATION, HISTONE MODIFICATION, NONCODING RNAS (NCRNAS) AND N6-METHYLADENOSINE (M6A) MODIFICATION IN ORGAN FIBROSIS, FOCUSING ON HEART, LIVER, LUNG AND KIDNEY. ADDITIONALLY, WE EMPHASIZE THE DIVERSITY OF EPIGENETICS IN THE CELLULAR AND MOLECULAR MECHANISMS RELATED TO FIBROSIS. FINALLY, THE POTENTIAL AND PROSPECT OF TARGETED THERAPY FOR FIBROSIS BASED ON EPIGENETIC IS DISCUSSED. 2021 16 3960 42 LONG NON-CODING RNAS: A DOUBLE-EDGED SWORD IN AGING KIDNEY AND RENAL DISEASE. AGING AS ONE OF INTRINSIC BIOLOGICAL PROCESSES IS A RISK FACTOR FOR MANY CHRONIC DISEASES. KIDNEY DISEASE IS A GLOBAL PROBLEM AND HEALTH CARE BURDEN WORLDWIDE. THE DIAGNOSIS OF KIDNEY DISEASE IS CURRENTLY BASED ON SERUM CREATININE AND UREA LEVELS. NOVEL BIOMARKERS MAY IMPROVE DIAGNOSTIC ACCURACY, THEREBY ALLOWING EARLY PREVENTION AND TREATMENT. OVER THE PAST FEW YEARS, ADVANCES IN GENOME ANALYSES HAVE IDENTIFIED AN EMERGING CLASS OF NONCODING RNAS THAT PLAY CRITICAL ROLES IN THE REGULATION OF GENE EXPRESSION AND EPIGENETIC REPROGRAMMING. LONG NONCODING RNAS (LNCRNAS) ARE PERVASIVELY TRANSCRIBED IN THE GENOME AND COULD BIND DNA, RNA AND PROTEIN. EMERGING EVIDENCE HAS DEMONSTRATED THAT LNCRNAS PLAYED AN IMPORTANT ROLE IN ALL STAGES OF KIDNEY DISEASE. TO DATE, ONLY SOME LNCRNAS WERE WELL IDENTIFIED AND CHARACTERIZED, BUT THE COMPLEXITY OF MULTILEVEL REGULATION OF TRANSCRIPTIONAL PROGRAMS INVOLVED IN THESE PROCESSES REMAINS UNDEFINED. IN THIS REVIEW, WE SUMMARIZED THE LNCRNA EXPRESSION PROFILING OF LARGE-SCALE IDENTIFIED LNCRNAS ON KIDNEY DISEASES INCLUDING ACUTE KIDNEY INJURY, CHRONIC KIDNEY DISEASE, DIABETIC NEPHROPATHY AND KIDNEY TRANSPLANTATION. WE FURTHER DISCUSSED A NUMBER OF ANNOTATED LNCRNAS LINKING WITH COMPLEX ETIOLOGY OF KIDNEY DISEASES. FINALLY, SEVERAL LNCRNAS WERE HIGHLIGHTED AS DIAGNOSTIC BIOMARKERS AND THERAPEUTIC TARGETS. TARGETING LNCRNAS MAY REPRESENT A PRECISE THERAPEUTIC STRATEGY FOR PROGRESSIVE RENAL FIBROSIS. 2021 17 2609 31 EPIGENETICS: A POTENTIAL KEY MECHANISM INVOLVED IN THE PATHOGENESIS OF CARDIORENAL SYNDROMES. EPIGENETICS IS DEFINED AS THE HERITABLE CHANGES IN GENE EXPRESSION PATTERNS WHICH ARE NOT DIRECTLY ENCODED BY MODIFICATIONS IN THE NUCLEOTIDE DNA SEQUENCE OF THE GENOME, INCLUDING HIGHER ORDER CHROMATIN ORGANIZATION, DNA METHYLATION, CYTOSINE MODIFICATIONS, COVALENT HISTONE TAIL MODIFICATIONS, AND SHORT NON-CODING RNA MOLECULES. RECENTLY, MUCH ATTENTION HAS BEEN PAID TO THE ROLE AND THE FUNCTION OF EPIGENETICS AND EPIMUTATIONS IN THE CELLULAR AND SUBCELLULAR PATHWAYS AND IN THE REGULATION OF GENES IN THE SETTING OF BOTH KIDNEY AND CARDIOVASCULAR DISEASE. INDEED, DEREGULATION OF HISTONE ALTERATIONS HAS BEEN HIGHLIGHTED IN A LARGE SPECTRUM OF RENAL AND CARDIAC DISEASE, INCLUDING CHRONIC AND ACUTE RENAL INJURY, RENAL AND CARDIAC FIBROSIS, CARDIAC HYPERTROPHY AND FAILURE, KIDNEY CONGENITAL ANOMALIES, RENAL HYPOXIA, AND DIABETIC RENAL COMPLICATIONS. NEVERTHELESS, THE ROLE OF EPIGENETICS IN THE PATHOGENESIS AND PATHOPHYSIOLOGY OF CARDIORENAL SYNDROMES IS CURRENTLY UNDEREXPLORED. GIVEN THE SIGNIFICANT CLINICAL RELEVANCE OF HEART-KIDNEY CROSSTALK, EFFORTS IN THE RESEARCH FOR NEW ACTION MECHANISMS CONCURRENTLY OPERATING IN BOTH PATHOLOGIES ARE THUS OF MAXIMUM INTEREST. THIS REVIEW FOCUSES ON EPIGENETIC MECHANISMS INVOLVED IN HEART AND KIDNEY DISEASE, AND THEIR POSSIBLE ROLE IN THE SETTING OF CARDIORENAL SYNDROMES. 2018 18 1604 29 DNA METHYLATION SUSTAINS "INFLAMED" MEMORY OF PERIPHERAL IMMUNE CELLS AGGRAVATING KIDNEY INFLAMMATORY RESPONSE IN CHRONIC KIDNEY DISEASE. THE INCIDENCE OF CHRONIC KIDNEY DISEASE (CKD) HAS RAPIDLY INCREASED IN THE PAST DECADES. A PROGRESSIVE LOSS OF KIDNEY FUNCTION CHARACTERIZES A PART OF CKD EVEN WITH INTENSIVE SUPPORTIVE TREATMENT. IRRESPECTIVE OF ITS ETIOLOGY, CKD PROGRESSION IS GENERALLY ACCOMPANIED WITH THE DEVELOPMENT OF CHRONIC KIDNEY INFLAMMATION THAT IS PATHOLOGICALLY FEATURED BY THE LOW-GRADE BUT CHRONIC ACTIVATION OF RECRUITED IMMUNE CELLS. CUMULATIVE EVIDENCE SUPPORT THAT ABERRANT DNA METHYLATION PATTERN OF DIVERSE PERIPHERAL IMMUNE CELLS, INCLUDING T CELLS AND MONOCYTES, IS CLOSELY ASSOCIATED WITH CKD DEVELOPMENT IN MANY CHRONIC DISEASE SETTINGS. THE CHANGE OF DNA METHYLATION PROFILE CAN SUSTAIN FOR A LONG TIME AND AFFECT THE FUTURE GENES EXPRESSION IN THE CIRCULATING IMMUNE CELLS EVEN AFTER THEY MIGRATE FROM THE CIRCULATION INTO THE INVOLVED KIDNEY. IT IS OF CLINICAL INTEREST TO REVEAL THE UNDERLYING MECHANISM OF HOW ALTERED DNA METHYLATION REGULATES THE INTENSITY AND THE TIME LENGTH OF THE INFLAMMATORY RESPONSE IN THE RECRUITED EFFECTOR CELLS. WE AND OTHERS RECENTLY DEMONSTRATED THAT ALTERED DNA METHYLATION OCCURS IN PERIPHERAL IMMUNE CELLS AND PROFOUNDLY CONTRIBUTES TO CKD DEVELOPMENT IN SYSTEMIC CHRONIC DISEASES, SUCH AS DIABETES AND HYPERTENSION. THIS REVIEW WILL SUMMARIZE THE CURRENT FINDINGS ABOUT THE INFLUENCE OF ABERRANT DNA METHYLATION ON CIRCULATING IMMUNE CELLS AND HOW IT POTENTIALLY DETERMINES THE OUTCOME OF CKD. 2021 19 1597 30 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 20 859 24 CHROMATIN DYNAMICS IN KIDNEY DEVELOPMENT AND FUNCTION. EPIGENETIC MECHANISMS ARE FUNDAMENTAL KEY FEATURES OF DEVELOPING CELLS CONNECTING DEVELOPMENTAL REGULATORY FACTORS TO CHROMATIN MODIFICATION. CHANGES IN THE ENVIRONMENT DURING RENAL DEVELOPMENT CAN HAVE LONG-LASTING EFFECTS ON THE PERMANENT TISSUE STRUCTURE AND THE LEVEL OF EXPRESSION OF IMPORTANT FUNCTIONAL GENES. THESE CHANGES ARE BELIEVED TO CONTRIBUTE TO KIDNEY DISEASE OCCURRENCE AND PROGRESSION. ALTHOUGH THE MECHANISMS OF EARLY PATTERNING AND CELL FATE HAVE BEEN WELL DESCRIBED FOR RENAL DEVELOPMENT, LITTLE IS KNOWN ABOUT ASSOCIATED EPIGENETIC MODIFICATIONS AND THEIR IMPACT ON HOW GENES INTERACT TO SPECIFY THE RENAL EPITHELIAL CELLS OF NEPHRONS AND HOW THIS SPECIFICATION IS RELEVANT TO MAINTAINING NORMAL RENAL FUNCTION. A BETTER UNDERSTANDING OF THE RENAL CELL-SPECIFIC EPIGENETIC MODIFICATIONS AND THE INTERACTION OF DIFFERENT CELL TYPES TO FORM THIS HIGHLY COMPLEX ORGAN WILL NOT ONLY HELP TO BETTER UNDERSTAND DEVELOPMENTAL DEFECTS AND EARLY LOSS OF KIDNEY FUNCTION IN CHILDREN, BUT ALSO HELP TO UNDERSTAND AND IMPROVE CHRONIC DISEASE PROGRESSION, CELL REGENERATION AND RENAL AGING. 2014