1 3887 58 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 2 6665 26 UPSTREAM AND DOWNSTREAM REGULATORS OF KLOTHO EXPRESSION IN CHRONIC KIDNEY DISEASE. KLOTHO IS A CRITICAL PROTEIN THAT PROTECTS THE KIDNEY. KLOTHO IS SEVERELY DOWNREGULATED IN CHRONIC KIDNEY DISEASE (CKD), AND ITS DEFICIENCY IS IMPLICATED IN THE PATHOGENESIS AND PROGRESSION OF CKD. CONVERSELY, AN INCREASE IN KLOTHO LEVELS RESULTS IN IMPROVED KIDNEY FUNCTION AND DELAYS CKD PROGRESSION, SUPPORTING THE NOTION THAT MODULATING KLOTHO LEVELS COULD REPRESENT A POSSIBLE THERAPEUTIC STRATEGY FOR CKD TREATMENT. NEVERTHELESS, THE REGULATORY MECHANISMS RESPONSIBLE FOR THE LOSS OF KLOTHO REMAIN ELUSIVE. PREVIOUS STUDIES HAVE DEMONSTRATED THAT OXIDATIVE STRESS, INFLAMMATION, AND EPIGENETIC MODIFICATIONS CAN MODULATE KLOTHO LEVELS. THESE MECHANISMS RESULT IN A DECREASE IN KLOTHO MRNA TRANSCRIPT LEVELS AND REDUCED TRANSLATION, THUS CAN BE GROUPED TOGETHER AS UPSTREAM REGULATORY MECHANISMS. HOWEVER, THERAPEUTIC STRATEGIES THAT AIM TO RESCUE KLOTHO LEVELS BY TARGETING THESE UPSTREAM MECHANISMS DO NOT ALWAYS RESULT IN INCREASED KLOTHO, INDICATING THE INVOLVEMENT OF OTHER REGULATORY MECHANISMS. EMERGING EVIDENCE HAS SHOWN THAT ENDOPLASMIC RETICULUM (ER) STRESS, THE UNFOLDED PROTEIN RESPONSE, AND ER-ASSOCIATED DEGRADATION ALSO AFFECT THE MODIFICATION, TRANSLOCATION, AND DEGRADATION OF KLOTHO, AND THUS ARE PROPOSED TO BE DOWNSTREAM REGULATORY MECHANISMS. HERE, WE DISCUSS THE CURRENT UNDERSTANDING OF UPSTREAM AND DOWNSTREAM REGULATORY MECHANISMS OF KLOTHO AND EXAMINE POTENTIAL THERAPEUTIC STRATEGIES TO UPREGULATE KLOTHO EXPRESSION FOR CKD TREATMENT. 2023 3 2001 19 EPIGENETIC AND NON-EPIGENETIC REGULATION OF KLOTHO IN KIDNEY DISEASE. KLOTHO IS A NOVEL RENOPROTECTIVE ANTI-AGING PROTEIN AVAILABLE IN MEMBRANE-BOUND OR SOLUBLE FORM. KLOTHO IS EXPRESSED IN BRAIN, PANCREAS, AND OTHER SOLID ORGANS BUT SHOWS HIGHEST EXPRESSION LEVELS IN THE KIDNEY. KLOTHO SUSTAINS NORMAL KIDNEY PHYSIOLOGY BUT KLOTHO REGULATION ALSO CONTRIBUTES TO THE PROGRESSION OF KIDNEY DISEASE. SYSTEMIC AND INTRARENAL LEVELS OF KLOTHO FALL DRASTICALLY DURING ACUTE KIDNEY INJURY, KIDNEY FIBROSIS, DIABETIC NEPHROPATHY, AND OTHER FORMS OF CHRONIC KIDNEY DISEASE, ETC. MOREOVER, EXOGENOUS SUPPLEMENTATION OR OVEREXPRESSION OF ENDOGENOUS KLOTHO ATTENUATES KIDNEY DISEASE. THE REGULATION OF ENDOGENOUS KLOTHO EXPRESSION INVOLVES EPIGENETIC AS WELL AS NON-EPIGENETIC MECHANISMS. THE EPIGENETIC MODIFICATIONS SUCH AS DNA METHYLATION, POST-TRANSLATIONAL HISTONE MODIFICATIONS, MIRNAS REGULATE THE CHANGE IN KLOTHO EXPRESSION IN KIDNEY DISEASE. NON-EPIGENETIC MECHANISMS SUCH AS ER STRESS, WNT SIGNALING, ACTIVATION OF THE RENIN ANGIOTENSIN SYSTEM (RAS), EXCESSIVE REACTIVE OXYGEN SPECIES AND CYTOKINE GENERATION, ALBUMIN OVERLOAD, AND PPAR-GAMMA SIGNALING ALSO CONTRIBUTE TO KLOTHO REGULATION. EVOLVING EVIDENCE HIGHLIGHT THE CAPACITY OF NATURAL PRODUCTS TO REGULATE KLOTHO EXPRESSION IN KIDNEY DISEASE. ALL THESE PRECLINICAL DATA SUGGEST THAT KLOTHO COULD BE A NOVEL BIOMARKER AS WELL AS THERAPEUTIC TARGET. HERE WE REVIEW THE DIFFERENT MECHANISMS OF KLOTHO REGULATION IN THE CONTEXT OF KLOTHO AS A BIOMARKER AND POTENTIAL THERAPEUTIC AGENT. 2021 4 2230 25 EPIGENETIC MODIFICATIONS OF KLOTHO EXPRESSION IN KIDNEY DISEASES. DEVELOPMENTS OF MANY RENAL DISEASES ARE SUBSTANTIALLY INFLUENCED BY EPIGENETIC MODIFICATIONS OF NUMEROUS GENES, MAINLY MEDIATED BY DNA METHYLATIONS, HISTONE MODIFICATIONS, AND MICRORNA INTERFERENCE; HOWEVER, NOT ALL GENE MODIFICATIONS CAUSALLY AFFECT THE DISEASE ONSET OR PROGRESSION. KLOTHO IS A CRITICAL GENE WHOSE REPRESSIONS IN VARIOUS PATHOLOGICAL CONDITIONS REPORTEDLY INVOLVE EPIGENETIC REGULATORY MECHANISMS. KLOTHO IS ALMOST UNEXCEPTIONALLY REPRESSED EARLY AFTER ACUTE OR CHRONIC RENAL INJURIES AND ITS LEVELS INVERSELY CORRELATED WITH THE DISEASE PROGRESSION AND SEVERITY. MOREOVER, THE STRATEGIES OF KLOTHO DEREPRESSION VIA EPIGENETIC MODULATIONS BENEFICIALLY CHANGE THE PATHOLOGICAL COURSES BOTH IN VITRO AND IN VIVO. HENCE, KLOTHO IS NOT ONLY CONSIDERED A BIOMARKER OF THE RENAL DISEASE BUT ALSO A POTENTIAL OR EVEN AN IDEAL TARGET OF THERAPEUTIC EPIGENETIC INTERVENTION. HERE, WE SUMMARIZE AND DISCUSS STUDIES THAT INVESTIGATE THE KLOTHO REPRESSION AND INTERVENTION IN RENAL DISEASES FROM AN EPIGENETIC POINT OF VIEW. THESE INFORMATION MIGHT SHED NEW SIGHTS INTO THE EFFECTIVE THERAPEUTIC STRATEGIES TO PREVENT AND TREAT VARIOUS RENAL DISORDERS. 2021 5 1665 26 DOWNREGULATION OF KIDNEY PROTECTIVE FACTORS BY INFLAMMATION: ROLE OF TRANSCRIPTION FACTORS AND EPIGENETIC MECHANISMS. CHRONIC KIDNEY DISEASE (CKD) IS ASSOCIATED TO AN INCREASED RISK OF DEATH, CKD PROGRESSION, AND ACUTE KIDNEY INJURY (AKI) EVEN FROM EARLY STAGES, WHEN GLOMERULAR FILTRATION RATE (GFR) IS PRESERVED. THE LINK BETWEEN EARLY CKD AND THESE RISKS IS UNCLEAR, SINCE THERE IS NO ACCUMULATION OF UREMIC TOXINS. HOWEVER, PATHOLOGICAL ALBUMINURIA AND KIDNEY INFLAMMATION ARE FREQUENT FEATURES OF EARLY CKD, AND THE PRODUCTION OF KIDNEY PROTECTIVE FACTORS MAY BE DECREASED. INDEED, KLOTHO EXPRESSION IS ALREADY DECREASED IN CKD CATEGORY G1 (NORMAL GFR). KLOTHO HAS ANTI-AGING AND NEPHROPROTECTIVE PROPERTIES, AND DECREASED KLOTHO LEVELS MAY CONTRIBUTE TO INCREASE THE RISK OF DEATH, CKD PROGRESSION, AND AKI. IN THIS REVIEW, WE DISCUSS THE DOWNREGULATION BY MEDIATORS OF INFLAMMATION OF MOLECULES WITH SYSTEMIC AND/OR RENAL LOCAL PROTECTIVE FUNCTIONS, EXEMPLIFIED BY KLOTHO AND PEROXISOME PROLIFERATOR-ACTIVATED RECEPTOR GAMMA COACTIVATOR-1ALPHA (PGC-1ALPHA), A TRANSCRIPTION FACTOR THAT PROMOTES MITOCHONDRIAL BIOGENESIS. CYTOKINES SUCH AS TWEAK, TNF-ALPHA, OR TRANSFORMING GROWTH FACTOR -BETA1 PRODUCED LOCALLY DURING KIDNEY INJURY OR RELEASED FROM INFLAMMATORY SITES AT OTHER ORGANS MAY DECREASE KIDNEY EXPRESSION OF KLOTHO AND PGC-1ALPHA OR LEAD TO SUBOPTIMAL RECRUITMENT OF THESE NEPHROPROTECTIVE PROTEINS. TRANSCRIPTION FACTORS (E.G., SMAD3 AND NF-KAPPAB) AND EPIGENETIC MECHANISMS (E.G., HISTONE ACETYLATION OR METHYLATION) CONTRIBUTE TO DOWNREGULATE THE EXPRESSION OF KLOTHO AND/OR PGC-1ALPHA, WHILE HISTONE CROTONYLATION PROMOTES PGC-1ALPHA EXPRESSION. NF-KAPPABIZ FACILITATES THE REPRESSIVE EFFECT OF NF-KAPPAB ON KLOTHO EXPRESSION. A DETAILED UNDERSTANDING OF THESE MEDIATORS MAY CONTRIBUTE TO THE DEVELOPMENT OF NOVEL THERAPEUTIC APPROACHES TO PREVENT CKD PROGRESSION AND ITS NEGATIVE IMPACT ON MORTALITY AND AKI. 2016 6 2589 20 EPIGENETICS OF PROGRESSION OF CHRONIC KIDNEY DISEASE: FACT OR FANTASY? EPIGENETIC MODIFICATIONS ARE IMPORTANT IN THE NORMAL FUNCTIONING OF THE CELL, FROM REGULATING DYNAMIC EXPRESSION OF ESSENTIAL GENES AND ASSOCIATED PROTEINS TO REPRESSING THOSE THAT ARE UNNEEDED. EPIGENETIC CHANGES ARE ESSENTIAL FOR DEVELOPMENT AND FUNCTIONING OF THE KIDNEY, AND ABERRANT METHYLATION, HISTONE MODIFICATIONS, AND EXPRESSION OF MICRORNA COULD LEAD TO CHRONIC KIDNEY DISEASE (CKD). HERE, EPIGENETIC MODIFICATIONS MODULATE TRANSFORMING GROWTH FACTOR BETA SIGNALING, INFLAMMATION, PROFIBROTIC GENES, AND THE EPITHELIAL-TO-MESENCHYMAL TRANSITION, PROMOTING RENAL FIBROSIS AND PROGRESSION OF CKD. IDENTIFICATION OF THESE EPIGENETIC CHANGES IS IMPORTANT BECAUSE THEY ARE POTENTIALLY REVERSIBLE AND MAY SERVE AS THERAPEUTIC TARGETS IN THE FUTURE TO PREVENT SUBSEQUENT RENAL FIBROSIS AND CKD. IN THIS REVIEW WE DISCUSS THE DIFFERENT TYPES OF EPIGENETIC CONTROL, METHODS TO STUDY EPIGENETIC MODIFICATIONS, AND HOW EPIGENETICS PROMOTES PROGRESSION OF CKD. 2013 7 3890 21 KLOTHO, PHOSPHATE AND INFLAMMATION/AGEING IN CHRONIC KIDNEY DISEASE. EVIDENCE IS EMERGING FOR THE INFLAMMATORY NATURE OF MANY AGEING-ASSOCIATED DISEASES, INCLUDING ATHEROSCLEROSIS, VASCULAR CALCIFICATION, DIABETES AND CHRONIC KIDNEY DISEASE (CKD), AMONG OTHERS. AGEING ITSELF RESULTS IN CHRONIC LOW-GRADE INFLAMMATION THAT PROMOTES END-ORGAN DAMAGE. INFLAMMATORY ORGAN DAMAGE, IN TURN, MAY CONTRIBUTE TO INFLAMMATION. RECENT RESEARCH HAS IDENTIFIED THE KIDNEY-SECRETED HORMONE KLOTHO AS A CENTRAL PLAYER AT THE AGEING-INFLAMMATION INTERFACE. THUS, SYSTEMIC OR LOCAL RENAL INFLAMMATION DECREASES KIDNEY KLOTHO EXPRESSION. KLOTHO DOWN-REGULATION MAY BE INDUCED BY SPECIFIC CYTOKINES SUCH AS TUMOUR NECROSIS FACTOR-ALPHA OR TWEAK THROUGH THE CANONICAL ACTIVATION OF THE INFLAMMATORY TRANSCRIPTION FACTOR NUCLEAR FACTOR KAPPA B (NFKAPPAB) AND, SPECIFICALLY RELA. IN ADDITION, INFLAMMATORY CYTOKINES LEAD TO THE EPIGENETIC INACTIVATION OF KLOTHO TRANSCRIPTION. KLOTHO ITSELF HAS ANTIOXIDANT AND ANTI-INFLAMMATORY PROPERTIES AND THE CANONICAL NFKAPPAB COMPONENT RELA IS ONE OF ITS TARGETS. KLOTHO IS A KEY REGULATOR OF PHOSPHATE BALANCE AND A ROLE OF PHOSPHATE IN AGEING HAS BEEN SHOWN. HOWEVER, THE POTENTIAL RELATIONSHIP BETWEEN PHOSPHATE AND INFLAMMATION REQUIRES FURTHER CLARIFICATION. A CORRECT UNDERSTANDING OF THESE INTERACTIONS MAY LEAD TO THE DESIGN OF NOVEL THERAPEUTIC APPROACHES TO CKD AND CKD-RELATED INFLAMMATORY AND AGEING FEATURES AS WELL AS TO INFLAMMATION/AGEING IN GENERAL. 2012 8 6510 24 TRANSCRIPTION FACTORS AND EPIGENETIC MODULATION: ITS THERAPEUTIC IMPLICATION IN CHRONIC KIDNEY DISEASE. RECENTLY EMERGING EVIDENCE HAS SHOWN THAT EPIGENETIC MECHANISMS ARE INVOLVED IN INITIATION AND PROGRESSION OF VARIOUS DISEASES, INCLUDING KIDNEY DISEASES. IN THE PRESENT ARTICLE, WE REVIEW THE CURRENT DATA REGARDING THE ROLE OF EPIGENETIC MODULATION IN CHRONIC KIDNEY DISEASE (CKD) AND KIDNEY FIBROSIS, INCLUDING DNA METHYLATION AND HISTONE MODIFICATION. ESPECIALLY WE FOCUSED ON THE ROLE OF TRANSCRIPTION FACTORS IN EPIGENETIC MODULATION AND THE POSSIBILITY OF THERAPEUTIC TARGET OF CKD. WE HAVE RECENTLY REPORTED THAT TRANSCRIPTION FACTOR KRUPPEL-LIKE FACTOR 4 (ALSO KNOWN AS GUT-ENRICHED KRUPPEL-LIKE FACTOR) IS EXPRESSED IN KIDNEY PODOCYTES (VISCERAL EPITHELIAL CELLS) AND MODULATES PODOCYTE PHENOTYPE BY GENE-SELECTIVE EPIGENETIC CONTROL. TARGETING TRANSCRIPTION FACTORS FOR EPIGENETIC MODIFICATION MAY BE A GOOD CANDIDATE FOR REMISSION AND REGRESSION OF CKD. IT IS NECESSARY FOR THE THERAPY OF CKD WITH AN EPIGENETIC-BASED APPROACH TO INVESTIGATE ORGAN-, TISSUE-, OR GENE-SPECIFIC TREATMENT METHODS FOR REDUCTION OF SIDE EFFECTS. 2015 9 5994 28 TGFBETA-INCURRED EPIGENETIC ABERRATIONS OF MIRNA AND DNA METHYLTRANSFERASE SUPPRESS KLOTHO AND POTENTIATE RENAL FIBROSIS. RENAL FIBROSIS IS A COMMON PATHOLOGICAL FEATURE OF CHRONIC KIDNEY DISEASES (CKD) AND ITS DEVELOPMENT AND PROGRESSION ARE SIGNIFICANTLY AFFECTED BY EPIGENETIC MODIFICATIONS SUCH AS ABERRANT MIRNA AND DNA METHYLATION. KLOTHO IS AN ANTI-AGING AND ANTI-FIBROTIC PROTEIN AND ITS EARLY DECLINE AFTER RENAL INJURY IS REPORTEDLY ASSOCIATED WITH ABERRANT DNA METHYLATION. HOWEVER, THE KEY UPSTREAM PATHOLOGICAL MEDIATORS AND THE MOLECULAR CASCADE LEADING TO EPIGENETIC KLOTHO SUPPRESSION ARE NOT EXCLUSIVELY ESTABLISHED. HERE WE INVESTIGATE THE EPIGENETIC MECHANISM OF KLOTHO DEFICIENCY AND ITS FUNCTIONAL RELEVANCE IN RENAL FIBROGENESIS. FIBROTIC KIDNEYS INDUCED BY UNILATERAL URETERAL OCCLUSION (UUO) DISPLAYED MARKED KLOTHO SUPPRESSION AND THE PROMOTER HYPERMETHYLATION. THESE ABNORMALITIES WERE LIKELY DUE TO DEREGULATED TRANSFORMING GROWTH FACTOR-BETA (TGFBETA) SINCE TGFBETA ALONE CAUSED THE SIMILAR EPIGENETIC ABERRATIONS IN CULTURED RENAL CELLS AND TGFBETA BLOCKADE PREVENTED THE ALTERATIONS IN UUO KIDNEY. FURTHER INVESTIGATION REVEALED THAT TGFBETA ENHANCED DNA METHYLTRANSFERASE (DNMT) 1 AND DNMT3A VIA INHIBITING MIR-152 AND MIR-30A IN BOTH RENAL CELLS AND FIBROTIC KIDNEYS. ACCORDINGLY THE BLOCKADE OF EITHER TGFBETA SIGNALING OR DNMT1/3A ACTIVITIES SIGNIFICANTLY RECOVERED THE KLOTHO LOSS AND ATTENUATED PRO-FIBROTIC PROTEIN EXPRESSION AND RENAL FIBROSIS. MOREOVER, KLOTHO KNOCKDOWN BY RNA INTERFERENCES ABOLISHED THE ANTI-FIBROTIC EFFECTS OF DNMT INHIBITION IN BOTH TGFBETA-TREATED RENAL CELL AND UUO KIDNEY, INDICATING THAT TGFBETA-MEDIATED MIR-152/30A INHIBITIONS, DNMT1/3A ABERRATIONS AND SUBSEQUENT KLOTHO LOSS CONSTITUTE A CRITICAL REGULATORY LOOP THAT ELIMINATES KLOTHO'S ANTI-FIBROTIC ACTIVITIES AND POTENTIATES RENAL FIBROGENESIS. THUS, OUR STUDY ELABORATES A NOVEL EPIGENETIC CASCADE OF RENAL FIBROGENESIS AND REVEALS THE POTENTIAL THERAPEUTIC TARGETS FOR TREATING THE RENAL FIBROSIS-ASSOCIATED KIDNEY DISEASES. 2017 10 3367 20 HISTONE METHYLTRANSFERASE EZH2: A POTENTIAL THERAPEUTIC TARGET FOR KIDNEY DISEASES. ENHANCER OF ZESTE HOMOLOG 2 (EZH2) IS A HISTONE-LYSINE N-METHYLTRANSFERASE ENZYME THAT CATALYZES THE ADDITION OF METHYL GROUPS TO HISTONE H3 AT LYSINE 27, LEADING TO GENE SILENCING. MUTATION OR OVER-EXPRESSION OF EZH2 HAS BEEN LINKED TO MANY CANCERS INCLUDING RENAL CARCINOMA. RECENT STUDIES HAVE SHOWN THAT EZH2 EXPRESSION AND ACTIVITY ARE ALSO INCREASED IN SEVERAL ANIMAL MODELS OF KIDNEY INJURY, SUCH AS ACUTE KIDNEY INJURY (AKI), RENAL FIBROSIS, DIABETIC NEPHROPATHY, LUPUS NEPHRITIS (LN), AND RENAL TRANSPLANTATION REJECTION. THE PHARMACOLOGICAL AND/OR GENETIC INHIBITION OF EZH2 CAN ALLEVIATE AKI, RENAL FIBROSIS, AND LN, BUT POTENTIATE PODOCYTE INJURY IN ANIMAL MODELS, SUGGESTING THAT THE FUNCTIONAL ROLE OF EZH2 VARIES WITH RENAL CELL TYPE AND DISEASE MODEL. IN THIS ARTICLE, WE SUMMARIZE THE ROLE OF EZH2 IN THE PATHOLOGY OF RENAL INJURY AND RELEVANT MECHANISMS AND HIGHLIGHT EZH2 AS A POTENTIAL THERAPEUTIC TARGET FOR KIDNEY DISEASES. 2021 11 6511 21 TRANSCRIPTION FACTORS AS THERAPEUTIC TARGETS IN CHRONIC KIDNEY DISEASE. THE GROWING NUMBER OF PATIENTS WITH CHRONIC KIDNEY DISEASE (CKD) IS RECOGNIZED AS AN EMERGING PROBLEM WORLDWIDE. RECENT STUDIES HAVE INDICATED THAT DEREGULATION OF TRANSCRIPTION FACTORS IS ASSOCIATED WITH THE ONSET OR PROGRESSION OF KIDNEY DISEASE. SEVERAL CLINICAL TRIALS INDICATED THAT REGRESSION OF CKD MAY BE FEASIBLE VIA ACTIVATION OF THE TRANSCRIPTION FACTOR NUCLEAR FACTOR ERYTHROID-2 RELATED FACTOR 2 (NRF2), WHICH SUGGESTS THAT TRANSCRIPTION FACTORS MAY BE POTENTIAL DRUG TARGETS FOR CKD. AGENTS STABILIZING HYPOXIA-INDUCIBLE FACTOR (HIF), WHICH MAY BE BENEFICIAL FOR RENAL ANEMIA AND RENAL PROTECTION, ARE ALSO NOW UNDER CLINICAL TRIAL. RECENTLY, WE HAVE REPORTED THAT THE TRANSCRIPTION FACTOR KRUPPEL-LIKE FACTOR 4 (KLF4) REGULATES THE GLOMERULAR PODOCYTE EPIGENOME, AND THAT THE ANTIPROTEINURIC EFFECT OF THE RENIN(-)ANGIOTENSIN SYSTEM BLOCKADE MAY BE PARTIALLY MEDIATED BY KLF4. KLF4 IS ONE OF THE YAMANAKA FACTORS THAT INDUCES IPS CELLS AND IS REPORTED TO BE INVOLVED IN EPIGENETIC REMODELING. IN THIS ARTICLE, WE SUMMARIZE THE TRANSCRIPTION FACTORS ASSOCIATED WITH CKD AND PARTICULARLY FOCUS ON THE POSSIBILITY OF TRANSCRIPTION FACTORS BEING NOVEL DRUG TARGETS FOR CKD THROUGH EPIGENETIC MODULATION. 2018 12 347 25 ALTERED DNA METHYLATION IN KIDNEY DISEASE: USEFUL MARKERS AND THERAPEUTIC TARGETS. RECENT STUDIES HAVE DEMONSTRATED THE ASSOCIATION OF ALTERED EPIGENOMES WITH LIFESTYLE-RELATED DISEASES. EPIGENETIC REGULATION PROMOTES BIOLOGICAL PLASTICITY IN RESPONSE TO ENVIRONMENTAL CHANGES, AND SUCH PLASTICITY MAY CAUSE A 'MEMORY EFFECT', A SUSTAINED EFFECT OF TRANSIENT TREATMENT OR AN INSULT IN THE COURSE OF LIFESTYLE-RELATED DISEASES. WE INVESTIGATED THE SIGNIFICANCE OF EPIGENETIC CHANGES IN SEVERAL GENES REQUIRED FOR RENAL INTEGRITY, INCLUDING THE NEPHRIN GENE IN PODOCYTES, AND THE SUSTAINED ANTI-PROTEINURIC EFFECT, FOCUSING ON THE TRANSCRIPTION FACTOR KRUPPEL-LIKE FACTOR 4 (KLF4). WE FURTHER REPORTED THE ROLE OF THE DNA REPAIR FACTOR LYSINE-ACETYL TRANSFERASE 5 (KAT5), WHICH ACTS COORDINATELY WITH KLF4, IN PODOCYTE INJURY CAUSED BY A HYPERGLYCEMIC STATE THROUGH THE ACCELERATION OF DNA DAMAGE AND EPIGENETIC ALTERATION. IN CONTRAST, KAT5 IN PROXIMAL TUBULAR CELLS PREVENTS ACUTE KIDNEY INJURY VIA GLOMERULAR FILTRATION REGULATION BY AN EPIGENETIC MECHANISM AS WELL AS PROMOTION OF DNA REPAIR, INDICATING THE CELL TYPE-SPECIFIC ACTION AND ROLES OF DNA REPAIR FACTORS. THIS REVIEW SUMMARIZES EPIGENETIC ALTERATIONS IN KIDNEY DISEASES, ESPECIALLY DNA METHYLATION, AND THEIR UTILITY AS MARKERS AND POTENTIAL THERAPEUTIC TARGETS. FOCUSING ON TRANSCRIPTION FACTORS OR DNA DAMAGE REPAIR FACTORS ASSOCIATED WITH EPIGENETIC CHANGES MAY BE MEANINGFUL DUE TO THEIR CELL-SPECIFIC EXPRESSION OR ACTION. WE BELIEVE THAT A BETTER UNDERSTANDING OF EPIGENETIC ALTERATIONS IN THE KIDNEY WILL LEAD TO THE DEVELOPMENT OF A NOVEL STRATEGY FOR CHRONIC KIDNEY DISEASE (CKD) TREATMENT. 2022 13 3326 22 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 14 1487 20 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 15 2542 21 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 16 4463 23 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 17 607 28 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 18 2293 22 EPIGENETIC REGULATION IN THE ACUTE KIDNEY INJURY TO CHRONIC KIDNEY DISEASE TRANSITION. EPIGENETIC MODIFICATIONS HAVE EMERGED AS A NEW, IMPORTANT CONTRIBUTOR TO GENE EXPRESSION REGULATION IN BOTH NORMAL AND PATHOPHYSIOLOGICAL CONDITIONS. EPIGENETICS HAVE BEEN STUDIED IN MANY DISEASES AND CONDITIONS SUCH AS ACUTE KIDNEY INJURY (AKI), A SYNDROME WITH A HIGH PREVALENCE THAT CARRIES A POOR PROGNOSIS WITH INCREASED MORBIDITY AND MORTALITY. IN ADDITION, IT HAS RECENTLY BEEN SHOWN THAT AKI INCREASES THE RISK FOR THE DEVELOPMENT OF CHRONIC KIDNEY DISEASE (CKD). THE SPECIFIC MOLECULAR MECHANISMS BY WHICH AKI INCREASES THE RISK OF CKD AND END STAGE RENAL DISEASE (ESRD) REMAIN UNKNOWN, ALTHOUGH THERE IS NEW EVIDENCE SUPPORTING A ROLE OF EPIGENETIC CHANGES. THE MOST STUDIED EPIGENETIC REGULATIONS IN AKI ARE CHROMATIN COMPACTION, DNA METHYLATION, AND HISTONE ACETYLATION/DEACETYLATION. THESE MODIFICATIONS PREDOMINANTLY INCREASE THE PRODUCTION OF PRO-INFLAMMATORY AND PROFIBROTIC CYTOKINES SUCH AS: MONOCYTE CHEMOATTRACTANT PROTEIN-1 (MCP-1), COMPLEMENT PROTEIN 3 (C3), TRANSFORMING GROWTH FACTOR BETA (TGF-BETA) THAT HAVE BEEN SHOWN FOR PERPETUATING INFLAMMATION, PROMOTING EPITHELIAL-TO-MESENCHYMAL TRANSITION (EMT) AND ULTIMATELY CAUSING RENAL FIBROSIS. A REVIEW OF EPIGENETIC MECHANISMS, THE PATHOPHYSIOLOGY OF AKI AND RECENT STUDIES THAT IMPLICATE EPIGENETIC MODIFICATIONS IN AKI AND IN THE TRANSITION TO CKD ARE DISCUSSED BELOW. 2015 19 3826 22 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 20 2195 24 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