1 2254 100 EPIGENETIC MODULATION: RESEARCH PROGRESS ON HISTONE ACETYLATION LEVELS IN MAJOR DEPRESSIVE DISORDERS. DEPRESSION IS A SERIOUS MENTAL ILLNESS AND A PREVALENT CONDITION WITH MULTIPLE AETIOLOGIES. THE IMPACT OF THE CURRENT THERAPEUTIC STRATEGIES IS LIMITED AND THE PATHOGENESIS OF THE ILLNESS IS NOT WELL UNDERSTOOD. ACCORDING TO PREVIOUS STUDIES, DEPRESSION ONSET IS INFLUENCED BY A VARIETY OF ENVIRONMENTAL AND GENETIC FACTORS, INCLUDING CHRONIC STRESS, ABERRANT CHANGES IN GENE EXPRESSION, AND HEREDITARY PREDISPOSITION. TRANSCRIPTIONAL REGULATION IN EUKARYOTES IS CLOSELY RELATED TO CHROMOSOME PACKING AND IS CONTROLLED BY HISTONE POST-TRANSLATIONAL MODIFICATIONS. THE DEVELOPMENT OF NEW ANTIDEPRESSANTS MAY PROCEED ALONG A NEW PATH WITH MEDICATIONS THAT TARGET EPIGENETICS. HISTONE DEACETYLASE INHIBITORS (HDACIS) ARE A CLASS OF COMPOUNDS THAT INTERFERE WITH THE FUNCTION OF HISTONE DEACETYLASES (HDACS). THIS REVIEW EXPLORES THE RELATIONSHIP BETWEEN HDACS AND DEPRESSION AND FOCUSES ON THE CURRENT KNOWLEDGE ON THEIR REGULATORY MECHANISM IN DEPRESSION AND THE POTENTIAL THERAPEUTIC USE OF HDACIS WITH ANTIDEPRESSANT EFFICACY IN PRECLINICAL RESEARCH. FUTURE RESEARCH ON INHIBITORS IS ALSO PROPOSED AND DISCUSSED. 2023 2 5926 35 TARGETING EPIGENETIC MECHANISMS FOR CHRONIC PAIN: A VALID APPROACH FOR THE DEVELOPMENT OF NOVEL THERAPEUTICS. CHRONIC PAIN IS A MULTIFACETED AND COMPLEX CONDITION. BROADLY CLASSIFIED INTO SOMATIC, VISCERAL, OR NEUROPATHIC PAIN, IT IS POORLY MANAGED DESPITE ITS PREVALENCE. CURRENT DRUGS USED FOR THE TREATMENT OF CHRONIC PAIN ARE LIMITED BY TOLERANCE WITH LONG-TERM USE, ABUSE POTENTIAL, AND MULTIPLE ADVERSE SIDE EFFECTS. THE PERSISTENT NATURE OF PAIN SUGGESTS THAT EPIGENETIC MACHINERY MAY BE A CRITICAL FACTOR DRIVING CHRONIC PAIN. IN THIS REVIEW, WE DISCUSS THE LATEST INSIGHTS INTO EPIGENETIC PROCESSES, INCLUDING DNA METHYLATION, HISTONE MODIFICATIONS, AND MICRORNAS, AND WE DESCRIBE THEIR INVOLVEMENT IN THE PATHOPHYSIOLOGY OF CHRONIC PAIN AND WHETHER EPIGENETIC MODIFICATIONS COULD BE APPLIED AS FUTURE THERAPEUTIC TARGETS FOR CHRONIC PAIN. WE PROVIDE EVIDENCE FROM EXPERIMENTAL MODELS AND TRANSLATIONAL RESEARCH IN HUMAN TISSUE THAT HAVE ENHANCED OUR UNDERSTANDING OF EPIGENETIC PROCESSES MEDIATING NOCICEPTION, AND WE THEN SPECULATE ON THE POTENTIAL FUTURE USE OF MORE SPECIFIC AND SELECTIVE AGENTS THAT TARGET EPIGENETIC MECHANISMS TO ATTENUATE PAIN. 2016 3 3855 26 IS THERE ANY THERAPEUTIC VALUE FOR THE USE OF HISTONE DEACETYLASE INHIBITORS FOR CHRONIC PAIN? CHRONIC PAIN IS A COMPLEX CLINICAL CONDITION THAT REDUCES THE QUALITY OF LIFE FOR BILLIONS OF PEOPLE. IN RECENT YEARS, THE ROLE OF EPIGENETIC MODULATION IN THE CONTROL OF LONG-TERM NEURONAL PLASTICITY HAS ATTRACTED THE ATTENTION OF PAIN RESEARCHERS. THE EPIGENETIC MECHANISMS INCLUDE COVALENT MODIFICATIONS OF DNA AND/OR HISTONE PROTEINS. MOUNTING EVIDENCE SUGGESTS THAT THE ACTIVITY OF HISTONE DEACETYLASES (HDACS) AND LEVELS OF HISTONE ACETYLATION ARE DYNAMIC AND THAT THESE ENZYMES MODULATE PAIN-RELATED SYNAPTIC PLASTICITY. THEREFORE, HDACS PLAY ESSENTIAL ROLES IN CHRONIC PAIN DEVELOPMENT AND MAINTENANCE. IN THIS MINI REVIEW, WE WILL DISCUSS THE ROLE OF HDACS IN THE PATHOGENESIS OF CHRONIC PAIN AND WILL CONSIDER THE THERAPEUTIC VALUE OF HDAC INHIBITORS IN TREATING CHRONIC PAIN. 2016 4 2551 34 EPIGENETICS IN PAIN AND ANALGESIA: AN IMMINENT RESEARCH FIELD. HERITABLE PHENOTYPES RESULTING FROM ENVIRONMENT-CAUSED CHANGES IN A CHROMOSOME WITHOUT ALTERATIONS IN THE DNA SEQUENCE ARE INCREASINGLY RECOGNIZED AS A BASIS OF PERSONALIZED THERAPY. EPIGENETIC MECHANISMS INCLUDE COVALENT MODIFICATIONS OF THE DNA (METHYLATION) OR OF THE DNA-PACKAGING HISTONES (E.G., DEACETYLATION OR PHOSPHORYLATION). IN ADDITION, REGULATORY NON-CODING RNA MOLECULES (MICRO-RNAS) EXERT EPIGENETIC ACTIONS. THIS LEADS TO DISRUPTION OR OTHERWISE MODIFIED EXPRESSION OF GENES. ENVIRONMENTAL INFLUENCES SUCH AS NUTRITIONAL FACTORS, EXPOSURE TO CHEMICALS OR DRUGS, BUT ALSO SOCIAL FACTORS APPEAR TO EXERT EPIGENETIC ACTIONS. HISTONE MODIFICATIONS AND DNA METHYLATION ARE ASSOCIATED WITH THE SUBJECT'S AGE. EPIGENETIC MECHANISMS CAN SILENCE THE EXPRESSION OF PRO- OR ANTINOCICEPTIVE GENES. TO THE EPIGENETIC CONTROL OF NOCICEPTION ADDS ITS CONTROL OF THE PHARMACODYNAMICS OR PHARMACOKINETICS OF ANALGESICS BY EPIGENETIC CONTROL OF DRUG TARGETS AND ANALGESICS METABOLIZING ENZYMES. ALTHOUGH EPIGENETICS-BASED STRATEGIES FOR PAIN THERAPY ARE NOT YET AVAILABLE, EXPERIMENTS IN RODENTS SUGGEST THAT RNA INTERFERENCE MAY BECOME A NEW THERAPY APPROACH FOR NEUROPATHIC AND OTHER PAIN. ANOTHER EPIGENETIC APPROACH TO ANALGESIC TREATMENT EMPLOYS INHIBITORS OF HISTONE DEACETYLASE THAT ACT ON THE EPIGENOME BY INDIRECTLY REMODELING THE SPATIAL CONFORMATION OF THE CHROMATIN. FINALLY, EPIGENETIC TECHNIQUES SUCH AS RNA INTERFERENCE HAVE BEEN EMPLOYED IN PAIN RESEARCH TO PROOF THE CONTRIBUTION OF CERTAIN PROTEINS TO NOCICEPTION. THUS, THE NEW FIELD OF EPIGENETICS BECOMES INCREASINGLY USED IN RESEARCH AND MANAGEMENT OF PAIN AND WILL COMPLEMENT GENETICS. THIS ARTICLE INTRODUCES EPIGENETICS TO PAIN AND SUMMARIZES THE CURRENT AND FUTURE UTILITY. 2011 5 6886 30 [ROLE OF EPIGENETIC MODIFICATION IN HIGHER BRAIN DYSFUNCTION AND AGING]. EPIGENETIC MECHANISMS TYPICALLY INVOLVE HERITABLE ALTERATIONS IN CHROMATIN STRUCTURE, WHICH, IN TURN, REGULATE GENE EXPRESSION. FUNDAMENTAL INSIGHTS ABOUT EPIGENETIC HERITABILITY HAVE COME FROM STUDIES OF CELL DIVISION AND DEVELOPMENT. HOWEVER, THERE IS INCREASING EVIDENCE THAT THE REGULATION OF CHROMATIN STRUCTURE THROUGH HISTONE MODIFICATIONS AND DNA METHYLATION MIGHT MEDIATE THE EXPRESSION OF KEY GENES INVOLVED IN ACQUIRED CHRONIC DISORDERS. THIS IDEA IS FASCINATING BECAUSE SIMILAR MECHANISMS ARE USED FOR TRIGGERING AND STORING LONG-TERM MEMORIES AT THE CELLULAR LEVEL DURING, FOR EXAMPLE, HIGHER-BRAIN DYSFUNCTION, STRESS DISEASE, DRUG DEPENDENCE, AGING, AND CHRONIC PAIN. THIS REVIEW WILL EXPLORE THE MOST CURRENT ISSUES IN THE FIELD OF EPIGENETICS, WITH A FOCUS ON NEXT LEVELS OF TRANSCRIPTIONAL MECHANISMS UNDERLYING AGING, ENRICHED ENVIRONMENT AND DRUG ADDICTION. EPIGENETIC MECHANISMS, WHICH ARE KEY CELLULAR AND MOLECULAR PROCESSES THAT INTEGRATE DIVERSE ENVIRONMENTAL STIMULI TO EXERT POTENT AND OFTEN LONG-LASTING CHANGES IN GENE EXPRESSION THROUGH THE REGULATION OF CHROMATIN STRUCTURE, CONTRIBUTE TO TRANSCRIPTIONAL AND BEHAVIORAL CHANGES. 2012 6 5928 21 TARGETING EPIGENETIC MECHANISMS FOR PAIN RELIEF. EPIGENETIC CHANGES ARE CHEMICAL MODIFICATIONS TO CHROMATIN THAT MODULATE GENE ACTIVITY WITHOUT ALTERING THE DNA SEQUENCE. WHILE RESEARCH ON EPIGENETICS HAS GROWN EXPONENTIALLY OVER THE PAST FEW YEARS, VERY FEW STUDIES HAVE INVESTIGATED EPIGENETIC MECHANISMS IN RELATION TO PAIN STATES. HOWEVER, EPIGENETIC MECHANISMS ARE CRUCIAL TO MEMORY FORMATION THAT REQUIRES SIMILAR SYNAPTIC PLASTICITY TO PAIN PROCESSING, INDICATING THAT THEY MAY PLAY A KEY ROLE IN THE CONTROL OF PAIN STATES. THIS ARTICLE REVIEWS THE EARLY EVIDENCE SUGGESTING THAT EPIGENETIC MECHANISMS ARE ENGAGED AFTER INJURY AND IN CHRONIC PAIN STATES, AND THAT DRUGS USED CLINICALLY TO TARGET THE EPIGENETIC MACHINERY FOR THE TREATMENT OF CANCER MIGHT BE USEFUL FOR THE MANAGEMENT OF CHRONIC PAIN. 2012 7 6802 19 [EPIGENETIC MECHANISMS IN MODELS OF CHRONIC PAIN - A TARGET FOR NOVEL THERAPY?]. EVIDENCE OF EPIGENETICS' ROLE IN PAIN RESPONSE IS ACCUMULATING IN RECENT YEARS. TIGHTLY REGULATED EPIGENETIC ALTERATIONS ON DNA AND HISTONES IN THE SENSORY CIRCUIT SHAPE THE PHYSIOLOGICAL RESPONSE TO INJURY. ALTERING THOSE EPIGENETIC PROCESSES HINDERS THERAPEUTIC POTENTIAL IN PAIN. THIS REVIEW PROVIDES AN OVERVIEW OF EPIGENOMIC MODIFICATION IN THE DEVELOPMENT OF CHRONIC PAIN, AND SUMMARIZES THE THERAPEUTIC POTENTIAL TO ALTER EPIGENETIC PROCESSES. 2018 8 2598 31 EPIGENETICS OF THE DEPRESSED BRAIN: ROLE OF HISTONE ACETYLATION AND METHYLATION. MAJOR DEPRESSIVE DISORDER IS A CHRONIC, REMITTING SYNDROME INVOLVING WIDELY DISTRIBUTED CIRCUITS IN THE BRAIN. STABLE ALTERATIONS IN GENE EXPRESSION THAT CONTRIBUTE TO STRUCTURAL AND FUNCTIONAL CHANGES IN MULTIPLE BRAIN REGIONS ARE IMPLICATED IN THE HETEROGENEITY AND PATHOGENESIS OF THE ILLNESS. EPIGENETIC EVENTS THAT ALTER CHROMATIN STRUCTURE TO REGULATE PROGRAMS OF GENE EXPRESSION HAVE BEEN ASSOCIATED WITH DEPRESSION-RELATED BEHAVIOR, ANTIDEPRESSANT ACTION, AND RESISTANCE TO DEPRESSION OR 'RESILIENCE' IN ANIMAL MODELS, WITH INCREASING EVIDENCE FOR SIMILAR MECHANISMS OCCURRING IN POSTMORTEM BRAINS OF DEPRESSED HUMANS. IN THIS REVIEW, WE DISCUSS RECENT ADVANCES IN OUR UNDERSTANDING OF EPIGENETIC CONTRIBUTIONS TO DEPRESSION, IN PARTICULAR THE ROLE OF HISTONE ACETYLATION AND METHYLATION, WHICH ARE REVEALING NOVEL MECHANISTIC INSIGHT INTO THE SYNDROME THAT MAY AID IN THE DEVELOPMENT OF NOVEL TARGETS FOR DEPRESSION TREATMENT. 2013 9 2523 37 EPIGENETICS AND THE TRANSITION FROM ACUTE TO CHRONIC PAIN. OBJECTIVE: THE OBJECTIVE OF THIS STUDY WAS TO REVIEW THE EPIGENETIC MODIFICATIONS INVOLVED IN THE TRANSITION FROM ACUTE TO CHRONIC PAIN AND TO IDENTIFY POTENTIAL TARGETS FOR THE DEVELOPMENT OF NOVEL, INDIVIDUALIZED PAIN THERAPEUTICS. BACKGROUND: EPIGENETICS IS THE STUDY OF HERITABLE MODIFICATIONS IN GENE EXPRESSION AND PHENOTYPE THAT DO NOT REQUIRE A CHANGE IN GENETIC SEQUENCE TO MANIFEST THEIR EFFECTS. ENVIRONMENTAL TOXINS, MEDICATIONS, DIET, AND PSYCHOLOGICAL STRESSES CAN ALTER EPIGENETIC PROCESSES SUCH AS DNA METHYLATION, HISTONE ACETYLATION, AND RNA INTERFERENCE. AS EPIGENETIC MODIFICATIONS POTENTIALLY PLAY AN IMPORTANT ROLE IN INFLAMMATORY CYTOKINE METABOLISM, STEROID RESPONSIVENESS, AND OPIOID SENSITIVITY, THEY ARE LIKELY KEY FACTORS IN THE DEVELOPMENT OF CHRONIC PAIN. ALTHOUGH OUR KNOWLEDGE OF THE HUMAN GENETIC CODE AND DISEASE-ASSOCIATED POLYMORPHISMS HAS GROWN SIGNIFICANTLY IN THE PAST DECADE, WE HAVE NOT YET BEEN ABLE TO ELUCIDATE THE MECHANISMS THAT LEAD TO THE DEVELOPMENT OF PERSISTENT PAIN AFTER NERVE INJURY OR SURGERY. DESIGN: THIS IS A FOCUSED LITERATURE REVIEW OF EPIGENETIC SCIENCE AND ITS RELATIONSHIP TO CHRONIC PAIN. RESULTS: SIGNIFICANT LABORATORY AND CLINICAL DATA SUPPORT THE NOTION THAT EPIGENETIC MODIFICATIONS ARE AFFECTED BY THE ENVIRONMENT AND LEAD TO DIFFERENTIAL GENE EXPRESSION. SIMILAR TO MECHANISMS INVOLVED IN THE DEVELOPMENT OF CANCER, NEURODEGENERATIVE DISEASE, AND INFLAMMATORY DISORDERS, THE LITERATURE ENDORSES AN IMPORTANT POTENTIAL ROLE FOR EPIGENETICS IN CHRONIC PAIN. CONCLUSIONS: EPIGENETIC ANALYSIS MAY IDENTIFY MECHANISMS CRITICAL TO THE DEVELOPMENT OF CHRONIC PAIN AFTER INJURY, AND MAY PROVIDE NEW PATHWAYS AND TARGET MECHANISMS FOR FUTURE DRUG DEVELOPMENT AND INDIVIDUALIZED MEDICINE. 2012 10 1686 34 DRUGGING THE PAIN EPIGENOME. MORE THAN 20% OF ADULTS WORLDWIDE EXPERIENCE DIFFERENT TYPES OF CHRONIC PAIN, WHICH ARE FREQUENTLY ASSOCIATED WITH SEVERAL COMORBIDITIES AND A DECREASE IN QUALITY OF LIFE. SEVERAL APPROVED PAINKILLERS ARE AVAILABLE, BUT CURRENT ANALGESICS ARE OFTEN HAMPERED BY INSUFFICIENT EFFICACY AND/OR SEVERE ADVERSE EFFECTS. CONSEQUENTLY, NOVEL STRATEGIES FOR SAFE, HIGHLY EFFICACIOUS TREATMENTS ARE HIGHLY DESIRABLE, PARTICULARLY FOR CHRONIC PAIN. EPIGENETIC MECHANISMS SUCH AS DNA METHYLATION, HISTONE MODIFICATIONS AND MICRORNAS (MIRNAS) STRONGLY AFFECT THE REGULATION OF GENE EXPRESSION, POTENTIALLY FOR LONG PERIODS OVER YEARS OR EVEN GENERATIONS, AND HAVE BEEN ASSOCIATED WITH PATHOPHYSIOLOGICAL PAIN. SEVERAL STUDIES, MOSTLY IN ANIMALS, REVEALED THAT INHIBITORS OF DNA METHYLATION, ACTIVATORS AND INHIBITORS OF HISTONE MODIFICATION AND MODULATORS OF MIRNAS REVERSE A NUMBER OF PATHOLOGICAL CHANGES IN THE PAIN EPIGENOME, WHICH ARE ASSOCIATED WITH ALTERED EXPRESSION OF PAIN-RELEVANT GENES. THIS EPIGENETIC MODULATION MIGHT THEN REDUCE THE NOCICEPTIVE RESPONSE AND PROVIDE NOVEL THERAPEUTIC OPTIONS FOR ANALGESIC THERAPY OF CHRONIC PAIN STATES. HOWEVER, A NUMBER OF CHALLENGES, SUCH AS NONSPECIFIC EFFECTS AND POOR DELIVERY TO TARGET CELLS AND TISSUES, HINDER THE RAPID DEVELOPMENT OF SUCH ANALGESICS. IN THIS REVIEW, WE CRITICALLY SUMMARIZE DATA ON EPIGENETICS AND PAIN, FOCUSING ON CHALLENGES IN CLINICAL DEVELOPMENT AS WELL AS POSSIBLE NEW APPROACHES TO THE DRUG MODULATION OF THE PAIN EPIGENOME. 2017 11 2611 28 EPIGENETICS: A PROMISING PARADIGM FOR BETTER UNDERSTANDING AND MANAGING PAIN. EPIGENETIC REGULATION OF GENE EXPRESSION IS A RAPIDLY GROWING AREA OF RESEARCH. CONSIDERING THE LONGEVITY AND PLASTICITY OF NEURONS, THE STUDIES ON EPIGENETIC PATHWAYS IN THE NERVOUS SYSTEM SHOULD BE OF SPECIAL INTEREST FOR BOTH EPIGENETICISTS AND NEUROSCIENTISTS. ACTIVATION OR INACTIVATION OF DIFFERENT EPIGENETIC PATHWAYS BECOMES MORE PRONOUNCED WHEN THE CELLS EXPERIENCE RAPID CHANGES IN THEIR ENVIRONMENT, AND SUCH CHANGES CAN BE EASILY CAUSED BY INJURY AND INFLAMMATION, RESULTING IN PAIN PERCEPTION OR DISTORTION OF PAIN PERCEPTION (EG, HYPERALGESIA). THEREFORE, IN THIS REGARD, THE FIELD OF PAIN IS AT AN ADVANTAGE TO STUDY THE EPIGENETIC PATHWAYS. MORE IMPORTANTLY, UNDERSTANDING PAIN FROM AN EPIGENETICS POINT OF VIEW WOULD PROVIDE A NEW PARADIGM FOR DEVELOPING DRUGS OR STRATEGIES FOR PAIN MANAGEMENT. IN THIS REVIEW, WE INTRODUCE BASIC CONCEPTS OF EPIGENETICS, INCLUDING CHROMATIN DYNAMICS, HISTONE MODIFICATIONS, DNA METHYLATION, AND RNA-INDUCED GENE SILENCING. IN ADDITION, WE PROVIDE EVIDENCE FROM PUBLISHED STUDIES SUGGESTING WIDE IMPLICATION OF DIFFERENT EPIGENETIC PATHWAYS WITHIN PAIN PATHWAYS. PERSPECTIVE: THIS ARTICLE PROVIDES A BRIEF OVERVIEW OF EPIGENETIC PATHWAYS FOR GENE REGULATION AND HIGHLIGHTS THEIR INVOLVEMENT IN PAIN. OUR GOAL IS TO EXPOSE THE READERS TO THESE CONCEPTS SO THAT PAIN-RELATED PHENOTYPES CAN BE INVESTIGATED FROM THE EPIGENETIC POINT OF VIEW. 2013 12 2586 31 EPIGENETICS OF PAIN MEDIATORS. PURPOSE OF REVIEW: THE FIELD OF EPIGENETICS CONTINUES ITS INFLUENTIAL RISE AS A MEANS TO BETTER UNDERSTAND AN ORGANISM'S UNIQUE DEVELOPMENTAL IDENTITY OVER A LIFESPAN. WHEREAS A GENOME IS CONSTANT AND UNCHANGING, AN EPIGENOME IS DYNAMIC AND ALTERABLE. EPIGENETIC CHANGES ARE IN RESPONSE TO INNUMERABLE INTERNAL AND EXTERNAL INFLUENCES INCLUDING ENVIRONMENTAL CHANGES SUCH AS DIET, EXERCISE, DISEASE, TOXINS, AND STRESS. EPIGENETICS IS OF PARTICULAR INTEREST IN THE MEDICAL RESEARCH COMMUNITY BOTH FOR THE POTENTIAL TO CAUSE DISEASE AND AS A TARGET FOR THERAPEUTIC INTERVENTIONS. THIS ARTICLE PROVIDES A SUCCINCT EXPLANATION OF THE POTENTIAL FOR EPIGENETICS TO INFLUENCE THE UNDERSTANDING OF PAIN AS WELL AS A REVIEW OF RELEVANT RESEARCH ON THE TOPIC. RECENT FINDINGS: STUDIES ON EPIGENETICS AND PAIN REMAIN LARGELY PRECLINICAL AND INVESTIGATE THE THEORETICAL ABILITY OF EPIGENETICS TO ALTER THE NOCICEPTIVE PATHWAYS BOTH IN THE PERIPHERY AND CENTRALLY. SIGNIFICANT EVIDENCE NOW EXISTS FOR THE ABILITY OF EPIGENETICS TO MODIFY BROADLY CATEGORIZED PAIN TYPES, INCLUDING INFLAMMATORY, NEUROPATHIC, VISCERAL, AND CANCER RELATED. SUMMARY: BOTH PATIENTS AND PROVIDERS RECOGNIZE THAT NOVEL MEDICATIONS FOR THE TREATMENT OF BOTH ACUTE AND CHRONIC PAIN CONDITIONS ARE SORELY NEEDED. THE UNDERSTANDING OF EPIGENETICS AND ITS INFLUENCE ON NOCICEPTION REMAINS IN RELATIVE INFANCY BUT EARLY EVIDENCE IS STRONG FOR POTENTIAL THERAPEUTIC BENEFITS TO TREAT THESE CONDITIONS. 2018 13 6124 33 THE EPIGENETIC MECHANISMS INVOLVED IN CHRONIC PAIN IN RODENTS: A MINI- REVIEW. CHRONIC PAIN IS A COMMON DISTRESSING NEUROLOGICAL DISORDER AND ABOUT 30% OF THE GLOBAL POPULATION SUFFERS FROM IT. IN ADDITION TO BEING HIGHLY PREVALENT, CHRONIC PAIN CAUSES A HEAVY ECONOMIC AND SOCIAL BURDEN. ALTHOUGH SUBSTANTIAL PROGRESS HAS BEEN ACHIEVED TO DISSECT THE UNDERLYING MECHANISM OF CHRONIC PAIN IN THE PAST FEW DECADES, THE INCIDENCE AND TREATMENT OF THIS NEUROLOGICAL ILLNESS IS YET NOT PROPERLY MANAGED IN CLINICAL PRACTICE. WHILE NERVE INJURY-, CHEMOTHERAPY- OR INFLAMMATION-INDUCED FUNCTIONAL REGULATION OF GENE EXPRESSION IN THE DORSAL ROOT GANGLION AND SPINAL CORD ARE EXTENSIVELY REPORTED TO BE INVOLVED IN THE PATHOGENIC PROCESS OF CHRONIC PAIN, THE SPECIFIC MECHANISM OF THESE ALTERED TRANSCRIPTIONAL PROFILE STILL REMAINS UNCLEAR. RECENT STUDIES HAVE SHOWN THAT EPIGENETIC MECHANISMS, INCLUDING DNA/RNA METHYLATION, HISTONE MODIFICATION AND CIRCULAR RNAS REGULATION, ARE INVOLVED IN THE OCCURRENCE AND DEVELOPMENT OF CHRONIC PAIN. IN THIS REVIEW, WE PROVIDE A DESCRIPTION OF RESEARCH ON THE ROLE OF EPIGENETIC MECHANISM IN CHRONIC PAIN, SUMMARIZE THE LATEST CLINICAL AND PRECLINICAL ADVANCE IN THIS FIELD, AND PROPOSE THE POTENTIAL DIRECTIONS FOR FURTHER RESEARCH TO ELUCIDATE THE MOLECULAR MECHANISM UNDERLYING THE PATHOGENESIS OF CHRONIC PAIN. 2022 14 2235 30 EPIGENETIC MODIFICATIONS, ALCOHOLIC BRAIN AND POTENTIAL DRUG TARGETS. ACUTE AND CHRONIC ALCOHOL EXPOSURE EVIDENTLY INFLUENCES EPIGENETIC CHANGES, BOTH TRANSIENTLY AND PERMANENTLY, AND THESE CHANGES IN TURN INFLUENCE A VARIETY OF CELLS AND ORGAN SYSTEMS THROUGHOUT THE BODY. MANY OF THE ALCOHOL-INDUCED EPIGENETIC MODIFICATIONS CAN CONTRIBUTE TO CELLULAR ADAPTATIONS THAT ULTIMATELY LEAD TO BEHAVIORAL TOLERANCE AND ALCOHOL DEPENDENCE. THE PERSISTENCE OF BEHAVIORAL CHANGES DEMONSTRATES THAT LONG-LASTING CHANGES IN GENE EXPRESSION, WITHIN PARTICULAR REGIONS OF THE BRAIN, MAY CONTRIBUTE IMPORTANTLY TO THE ADDICTION PHENOTYPE. THE RESEARCH ACTIVITIES OVER THE PAST YEARS HAVE DEMONSTRATED A CRUCIAL ROLE OF EPIGENETIC MECHANISMS IN CAUSING LONG LASTING AND TRANSIENT CHANGES IN THE EXPRESSION OF SEVERAL GENES IN DIVERSE TISSUES, INCLUDING BRAIN. THIS HAS STIMULATED RECENT RESEARCH WORK THAT IS AIMED AT CHARACTERIZING THE INFLUENCE OF EPIGENETIC REGULATORY EVENTS IN MEDIATING THE LONG LASTING AND TRANSIENT EFFECTS OF ALCOHOL ABUSE ON THE BRAIN IN HUMANS AND ANIMAL MODELS OF ALCOHOL ADDICTION. IN THIS STUDY, WE UPDATE OUR CURRENT UNDERSTANDING OF THE IMPACT OF ALCOHOL EXPOSURE ON EPIGENETIC MECHANISMS IN THE BRAIN AND REFURBISH THE KNOWLEDGE OF EPIGENETICS IN THE DIRECTION OF NEW DRUGS DEVELOPMENT. 2016 15 2550 32 EPIGENETICS IN OSTEOARTHRITIS: POTENTIAL OF HDAC INHIBITORS AS THERAPEUTICS. OSTEOARTHRITIS (OA) IS THE MOST COMMON JOINT DISEASE AND THE LEADING CAUSE OF CHRONIC DISABILITY IN MIDDLE-AGED AND OLDER POPULATIONS WORLDWIDE. THE DEVELOPMENT OF DISEASE MODIFYING THERAPY FOR OA IS IN ITS INFANCY LARGELY BECAUSE THE REGULATORY MECHANISMS FOR THE MOLECULAR EFFECTORS OF OA PATHOGENESIS ARE POORLY UNDERSTOOD. RECENT STUDIES IDENTIFIED EPIGENETIC EVENTS AS A CRITICAL REGULATOR OF MOLECULAR PLAYERS INVOLVED IN THE INDUCTION AND DEVELOPMENT OF OA. EPIGENETIC MECHANISMS INCLUDE DNA METHYLATION, NON-CODING RNA AND HISTONE MODIFICATIONS. THE AIM OF THIS REVIEW IS TO BRIEFLY HIGHLIGHT THE RECENT ADVANCES IN THE EPIGENETICS OF CARTILAGE AND POTENTIAL OF HDACS (HISTONE DEACETYLASES) INHIBITORS IN THE THERAPEUTIC MANAGEMENT OF OA. WE SUMMARIZE THE RECENT STUDIES UTILIZING HDAC INHIBITORS AS POTENTIAL THERAPEUTICS FOR INHIBITING DISEASE PROGRESSION AND PREVENTING THE CARTILAGE DESTRUCTION IN OA. HDACS CONTROL NORMAL CARTILAGE DEVELOPMENT AND HOMEOSTASIS AND UNDERSTANDING THE IMPACT OF HDACS INHIBITORS ON THE DISEASE PATHOGENESIS IS OF INTEREST BECAUSE OF ITS IMPORTANCE IN AFFECTING OVERALL CARTILAGE HEALTH AND HOMEOSTASIS. THESE FINDINGS ALSO SHED NEW LIGHT ON CARTILAGE DISEASE PATHOPHYSIOLOGY AND PROVIDE SUBSTANTIAL EVIDENCE THAT HDACS MAY BE POTENTIAL NOVEL THERAPEUTIC TARGETS IN OA. 2018 16 4321 26 MICRORNAS IN MAJOR DEPRESSIVE DISORDER. MAJOR DEPRESSIVE DISORDER (MDD) IS A SEVERE AND CHRONIC PSYCHIATRIC DISORDER WITH A HIGH PREVALENCE IN THE POPULATION. ALTHOUGH OUR UNDERSTANDING OF ITS PATHOPHYSIOLOGICAL MECHANISMS HAS SIGNIFICANTLY INCREASED OVER THE YEARS, AVAILABLE TREATMENTS STILL PRESENT SEVERAL LIMITATIONS AND ARE NOT EFFECTIVE TO ALL MDD PATIENTS. EPIGENETIC MECHANISMS HAVE RECENTLY BEEN SUGGESTED TO PLAY KEY ROLES IN MDD PATHOGENESIS AND TREATMENT, INCLUDING THE EFFECTS OF SMALL NONCODING RNAS KNOWN AS MICRORNAS (MIRNAS). MIRNAS CAN MODULATE GENE EXPRESSION POSTTRANSCRIPTIONALLY BY INTERFERING WITH THE STABILITY AND TRANSLATION OF MESSENGER RNA MOLECULES AND ARE ALSO KNOWN TO CROSS-TALK WITH OTHER EPIGENETIC MECHANISMS. IN THIS REVIEW, WE WILL SUMMARIZE AND DISCUSS RECENT FINDINGS OF ALTERATIONS IN MIRNAS IN TISSUES OF PATIENTS WITH MDD AND EVIDENCE OF TREATMENT-INDUCED EFFECTS IN THESE MOLECULES. 2019 17 2454 28 EPIGENETIC TARGETING OF HISTONE DEACETYLASES IN DIAGNOSTICS AND TREATMENT OF DEPRESSION. DEPRESSION IS A HIGHLY PREVALENT, DISABLING, AND OFTEN CHRONIC ILLNESS THAT PLACES SUBSTANTIAL BURDENS ON PATIENTS, FAMILIES, HEALTHCARE SYSTEMS, AND THE ECONOMY. A SUBSTANTIAL MINORITY OF PATIENTS ARE UNRESPONSIVE TO CURRENT THERAPIES, SO THERE IS AN URGENT NEED TO DEVELOP MORE BROADLY EFFECTIVE, ACCESSIBLE, AND TOLERABLE THERAPIES. PHARMACOLOGICAL REGULATION OF HISTONE ACETYLATION LEVEL HAS BEEN INVESTIGATED AS ONE POTENTIAL CLINICAL STRATEGY. HISTONE ACETYLATION STATUS IS CONSIDERED A POTENTIAL DIAGNOSTIC BIOMARKER FOR DEPRESSION, WHILE INHIBITORS OF HISTONE DEACETYLASES (HDACS) HAVE GARNERED INTEREST AS NOVEL THERAPEUTICS. THIS REVIEW DESCRIBES RECENT ADVANCES IN OUR KNOWLEDGE OF HISTONE ACETYLATION STATUS IN DEPRESSION AND THE THERAPEUTIC POTENTIAL OF HDAC INHIBITORS. 2021 18 2412 38 EPIGENETIC SIDE-EFFECTS OF COMMON PHARMACEUTICALS: A POTENTIAL NEW FIELD IN MEDICINE AND PHARMACOLOGY. THE TERM "EPIGENETICS" REFERS TO DNA AND CHROMATIN MODIFICATIONS THAT PERSIST FROM ONE CELL DIVISION TO THE NEXT, DESPITE A LACK OF CHANGE IN THE UNDERLYING DNA SEQUENCE. THE "EPIGENOME" REFERS TO THE OVERALL EPIGENETIC STATE OF A CELL, AND SERVES AS AN INTERFACE BETWEEN THE ENVIRONMENT AND THE GENOME. THE EPIGENOME IS DYNAMIC AND RESPONSIVE TO ENVIRONMENTAL SIGNALS NOT ONLY DURING DEVELOPMENT, BUT ALSO THROUGHOUT LIFE; AND IT IS BECOMING INCREASINGLY APPARENT THAT CHEMICALS CAN CAUSE CHANGES IN GENE EXPRESSION THAT PERSIST LONG AFTER EXPOSURE HAS CEASED. HERE WE PRESENT THE HYPOTHESIS THAT COMMONLY-USED PHARMACEUTICAL DRUGS CAN CAUSE SUCH PERSISTENT EPIGENETIC CHANGES. DRUGS MAY ALTER EPIGENETIC HOMEOSTASIS BY DIRECT OR INDIRECT MECHANISMS. DIRECT EFFECTS MAY BE CAUSED BY DRUGS WHICH AFFECT CHROMATIN ARCHITECTURE OR DNA METHYLATION. FOR EXAMPLE THE ANTIHYPERTENSIVE HYDRALAZINE INHIBITS DNA METHYLATION. AN EXAMPLE OF AN INDIRECTLY ACTING DRUG IS ISOTRETINOIN, WHICH HAS TRANSCRIPTION FACTOR ACTIVITY. A TWO-TIER MECHANISM IS POSTULATED FOR INDIRECT EFFECTS IN WHICH ACUTE EXPOSURE TO A DRUG INFLUENCES SIGNALING PATHWAYS THAT MAY LEAD TO AN ALTERATION OF TRANSCRIPTION FACTOR ACTIVITY AT GENE PROMOTERS. THIS STIMULATION RESULTS IN THE ALTERED EXPRESSION OF RECEPTORS, SIGNALING MOLECULES, AND OTHER PROTEINS NECESSARY TO ALTER GENETIC REGULATORY CIRCUITS. WITH MORE CHRONIC EXPOSURE, CELLS ADAPT BY AN UNKNOWN HYPOTHETICAL PROCESS THAT RESULTS IN MORE PERMANENT MODIFICATIONS TO DNA METHYLATION AND CHROMATIN STRUCTURE, LEADING TO ENDURING ALTERATION OF A GIVEN EPIGENETIC NETWORK. THEREFORE, ANY EPIGENETIC SIDE-EFFECT CAUSED BY A DRUG MAY PERSIST AFTER THE DRUG IS DISCONTINUED. IT IS FURTHER PROPOSED THAT SOME IATROGENIC DISEASES SUCH AS TARDIVE DYSKINESIA AND DRUG-INDUCED SLE ARE EPIGENETIC IN NATURE. IF THIS HYPOTHESIS IS CORRECT THE CONSEQUENCES FOR MODERN MEDICINE ARE PROFOUND, SINCE IT WOULD IMPLY THAT OUR CURRENT UNDERSTANDING OF PHARMACOLOGY IS AN OVERSIMPLIFICATION. WE PROPOSE THAT EPIGENETIC SIDE-EFFECTS OF PHARMACEUTICALS MAY BE INVOLVED IN THE ETIOLOGY OF HEART DISEASE, CANCER, NEUROLOGICAL AND COGNITIVE DISORDERS, OBESITY, DIABETES, INFERTILITY, AND SEXUAL DYSFUNCTION. IT IS SUGGESTED THAT A SYSTEMS BIOLOGY APPROACH EMPLOYING MICROARRAY ANALYSES OF GENE EXPRESSION AND METHYLATION PATTERNS CAN LEAD TO A BETTER UNDERSTANDING OF LONG-TERM SIDE-EFFECTS OF DRUGS, AND THAT IN THE FUTURE, EPIGENETIC ASSAYS SHOULD BE INCORPORATED INTO THE SAFETY ASSESSMENT OF ALL PHARMACEUTICAL DRUGS. THIS NEW APPROACH TO PHARMACOLOGY HAS BEEN TERMED "PHAMACOEPIGENOMICS", THE IMPACT OF WHICH MAY BE EQUAL TO OR GREATER THAN THAT OF PHARMACOGENETICS. WE PROVIDE HERE AN OVERVIEW OF THIS POTENTIALLY MAJOR NEW FIELD IN PHARMACOLOGY AND MEDICINE. 2009 19 1199 30 CORTICOTROPIN RELEASING FACTOR-BINDING PROTEIN (CRF-BP) AS A POTENTIAL NEW THERAPEUTIC TARGET IN ALZHEIMER'S DISEASE AND STRESS DISORDERS. ALZHEIMER'S DISEASE IS THE MOST COMMON CAUSE OF DEMENTIA AND ONE OF THE MOST COMPLEX HUMAN NEURODEGENERATIVE DISEASES. NUMEROUS STUDIES HAVE DEMONSTRATED A CRITICAL ROLE OF THE ENVIRONMENT IN THE PATHOGENESIS AND PATHOPHYSIOLOGY OF THE DISEASE, WHERE DAILY LIFE STRESS PLAYS AN IMPORTANT ROLE. A LOT OF EPIGENETIC STUDIES HAVE LED TO THE CONCLUSION THAT CHRONIC STRESS AND STRESS-RELATED DISORDERS PLAY AN IMPORTANT PART IN THE ONSET OF NEURODEGENERATIVE DISORDERS, AND AN ENORMOUS AMOUNT OF RESEARCH YIELDED VALUABLE DISCOVERIES BUT HAS SO FAR NOT LED TO THE DEVELOPMENT OF EFFECTIVE TREATMENT STRATEGIES FOR ALZHEIMER'S DISEASE. CORTICOTROPIN-RELEASING FACTOR (CRF) IS ONE OF THE MAJOR HORMONES AND AT THE SAME TIME A NEUROPEPTIDE ACTING IN STRESS RESPONSE. DEREGULATION OF PROTEIN LEVELS OF CRF IS INVOLVED IN THE PATHOGENESIS OF ALZHEIMER'S DISEASE, BUT LITTLE IS KNOWN ABOUT THE PRECISE ROLES OF CRF AND ITS BINDING PROTEIN, CRF-BP, IN NEURODEGENERATIVE DISEASES. IN THIS REVIEW, WE SUMMARIZE THE KEY EVIDENCE FOR AND AGAINST THE INVOLVEMENT OF STRESS-ASSOCIATED MODULATION OF THE CRF SYSTEM IN THE PATHOGENESIS OF ALZHEIMER'S DISEASE AND DISCUSS HOW RECENT FINDINGS COULD LEAD TO NEW POTENTIAL TREATMENT POSSIBILITIES IN ALZHEIMER'S DISEASE BY USING CRF-BP AS A THERAPEUTIC TARGET. 2019 20 6061 26 THE DEVELOPMENT PROSPECTION OF HDAC INHIBITORS AS A POTENTIAL THERAPEUTIC DIRECTION IN ALZHEIMER'S DISEASE. ALZHEIMER'S DISEASE (AD) IS A CHRONIC NEURODEGENERATIVE DISEASE, WHICH IS ASSOCIATED WITH LEARNING AND MEMORY IMPAIRMENT IN THE ELDERLY. RECENT STUDIES HAVE FOUND THAT TREATING AD IN THE WAY OF CHROMATIN REMODELING VIA HISTONE ACETYLATION IS A PROMISING THERAPEUTIC REGIMEN. IN A NUMBER OF RECENT STUDIES, INHIBITORS OF HISTONE DEACETYLASE (HDACS) HAVE BEEN FOUND TO BE A NOVEL PROMISING THERAPEUTIC AGENTS FOR NEUROLOGICAL DISORDERS, PARTICULARLY FOR AD AND OTHER NEURODEGENERATIVE DISEASES. ALTHOUGH HDAC INHIBITORS HAVE THE ABILITY TO AMELIORATE COGNITIVE IMPAIRMENT, SUCCESSFUL TREATMENTS IN THE CLASSIC AD ANIMAL MODEL ARE RARELY TRANSLATED INTO CLINICAL TRIALS. AS FOR THE REDUCTION OF UNWANTED SIDE EFFECTS, THE DEVELOPMENT OF HDAC INHIBITORS WITH INCREASED ISOFORM SELECTIVITY OR SEEKING OTHER DIRECTIONS IS A KEY ISSUE THAT NEEDS TO BE ADDRESSED. THE REVIEW FOCUSED ON LITERATURES ON EPIGENETIC MECHANISMS IN RECENT YEARS, ESPECIALLY ON HISTONE ACETYLATION IN TERMS OF THE ENHANCEMENT OF SPECIFICITY, EFFICACY AND AVOIDING SIDE EFFECTS FOR TREATING AD. 2017