1 583 97 BEHAVIORAL DIFFERENCES OF MALE WISTAR RATS FROM DIFFERENT VENDORS IN VULNERABILITY AND RESILIENCE TO CHRONIC MILD STRESS ARE REFLECTED IN EPIGENETIC REGULATION AND EXPRESSION OF P11. OUTBRED RAT LINES SUCH AS WISTAR RATS ARE COMMONLY USED FOR MODELS OF DEPRESSIVE DISORDERS. SUCH RATS ARISE FROM RANDOM MATING SCHEDULES. HENCE, GENETIC DRIFT OCCURS IN OUTBRED POPULATIONS WHICH COULD LEAD TO GENOTYPIC AND PHENOTYPIC HETEROGENEITY BETWEEN RATS FROM DIFFERENT VENDORS. ADDITIONALLY, VENDOR SPECIFIC REARING CONDITIONS COULD CONTRIBUTE TO INTRASTRAIN VARIABILITY. IN THE PRESENT STUDY DIFFERENCES IN BEHAVIORAL RESPONSES TO THE CHRONIC MILD STRESS (CMS) MODEL OF DEPRESSION WITHIN WISTAR RAT STRAINS FROM DIFFERENT VENDORS ARE DESCRIBED. DNA METHYLATION STUDIES AND MRNA EXPRESSION ANALYSIS OF P11 REVEALED THAT THE BEHAVIORAL DIFFERENCES BETWEEN THE SUBSTRAINS ARE REFLECTED AT THE EPIGENETIC AND GENETIC LEVEL. THE RESULTS SUGGEST THAT THERE ARE BREEDER-DEPENDENT DIFFERENCES IN VULNERABILITY TO STRESS IN THE CMS MODEL OF DEPRESSION, WHICH MIGHT BEAR ON THE VALIDITY OF THE MODEL AND CONTRIBUTE TO CONTRADICTORY FINDINGS AND DIFFICULTIES OF REPLICATION BETWEEN LABORATORIES. P11 MRNA EXPRESSION SEEMS TO BE DIFFERENTLY REGULATED DEPENDING ON THE QUALITY OF THE STRESS RESPONSE EVOKED BY CMS EXPOSURE. 2016 2 5467 34 RESILIENT PHENOTYPE IN CHRONIC MILD STRESS PARADIGM IS ASSOCIATED WITH ALTERED EXPRESSION LEVELS OF MIR-18A-5P AND SEROTONIN 5-HT(1A) RECEPTOR IN DORSAL PART OF THE HIPPOCAMPUS. DISTURBED SEROTONERGIC SIGNALING IN THE HIPPOCAMPUS OBSERVED IN MANY INDIVIDUALS VULNERABLE TO STRESS HAS BEEN SUGGESTED AS ONE OF THE PRIMARY FACTORS CONTRIBUTING TO THE DEVELOPMENT OF DEPRESSION. HOWEVER, LITTLE IS KNOWN ABOUT THE PHYSIOLOGY OF THE BRAIN IN THE RESILIENT PHENOTYPE. RESILIENT SUBJECTS MAINTAIN A POSITIVE MOOD AND PSYCHOLOGICAL BALANCE DESPITE BEING UNDER THE STRESS INFLUENCE. IN OUR STUDY, WE GENERATED STRESS-VULNERABLE AND RESILIENT RATS BY USING A CHRONIC MILD STRESS (CMS) PARADIGM. USING DIFFERENT MOLECULAR APPROACHES, WE REVEALED THAT RESILIENT ANIMALS EXHIBITED A SIGNIFICANTLY DECREASED EXPRESSION LEVEL OF MIR-18A-5P AND, IN THE SAME TIME, AN ELEVATED LEVEL OF 5-HT1AR IN DORSAL, BUT NOT VENTRAL, PART OF THE HIPPOCAMPUS. DESCRIBED BIOCHEMICAL CHANGES WERE NOT OBSERVED IN ANIMALS BEHAVIORALLY VULNERABLE TO STRESS. FURTHER, IN VITRO ANALYSIS SHOWED THAT MIR-18A-5P MAY BE A NEGATIVE EPIGENETIC REGULATOR OF 5-HT1AR SINCE THE TREATMENT OF ADULT HIPPOCAMPAL NEURONS WITH MIR-18A-5P MIMIC SIGNIFICANTLY LOWERED THE EXPRESSION LEVEL OF MRNA ENCODING 5-HT1AR. MOREOVER, BIOINFORMATIC ANALYSIS OF POTENTIAL TARGET GENES EXPRESSED IN THE HIPPOCAMPUS AND BEING REGULATED BY MIR-18A-5P SHOWED THAT THIS MICRORNA MAY REGULATE BIOLOGICAL PROCESSES, SUCH AS AXONOGENESIS, WHICH ARE IMPORTANT IN THE FUNCTIONING OF THE HIPPOCAMPUS IN BOTH RATS AND HUMANS. ALL THESE MOLECULAR FEATURES MAY CONTRIBUTE TO SEROTONERGIC HOMEOSTATIC BALANCE AT THE LEVEL OF SEROTONIN TURNOVER OBSERVED IN HIPPOCAMPI OF RESILIENT BUT NOT STRESS-VULNERABLE RATS. DELINEATION OF FURTHER MOLECULAR AND BIOCHEMICAL MARKERS UNDERLYING RESILIENCE TO STRESS MAY CONTRIBUTE TO THE DEVELOPMENT OF NEW ANTIDEPRESSANT STRATEGIES WHICH WILL RESTORE RESILIENT PHENOTYPE IN DEPRESSED PATIENTS. 2019 3 989 25 CHRONIC SOCIAL DEFEAT STRESS DIFFERENTIALLY REGULATES THE EXPRESSION OF BDNF TRANSCRIPTS AND EPIGENETIC MODIFYING ENZYMES IN SUSCEPTIBLE AND RESILIENT MICE. OBJECTIVES: ALTHOUGH STRESS IS CONSIDERED A PRIMARY RISK FACTOR FOR NEUROPSYCHIATRIC DISORDERS, A MAJORITY OF INDIVIDUALS ARE RESILIENT TO THE EFFECTS OF STRESS EXPOSURE AND SUCCESSFULLY ADAPT TO ADVERSE LIFE EVENTS, WHILE OTHERS, THE SO-CALLED SUSCEPTIBLE INDIVIDUALS, MAY HAVE PROBLEMS TO PROPERLY ADAPT TO ENVIRONMENTAL CHANGES. HOWEVER, THE MECHANISMS UNDERLYING THESE DIFFERENT RESPONSES TO STRESS EXPOSURE ARE POORLY UNDERSTOOD.METHODS: ADULT MALE C57BL/6J MICE WERE EXPOSED TO CHRONIC SOCIAL DEFEAT STRESS PROTOCOL AND LEVELS OF BRAIN DERIVED NEUROTROPHIC FACTOR (BDNF) TRANSCRIPTS AND EPIGENETIC MODIFYING ENZYMES WERE ANALYSED BY REAL-TIME PCR IN THE HIPPOCAMPUS (HPC) AND PREFRONTAL CORTEX (PFC) OF SUSCEPTIBLE AND RESILIENT MICE.RESULTS: WE FOUND A SELECTIVE REDUCTION OF BDNF-6 TRANSCRIPT IN THE HPC AND AN INCREASE OF BDNF-4 TRANSCRIPT IN THE PFC OF SUSCEPTIBLE MICE. MOREOVER, SUSCEPTIBLE MICE SHOWED A SELECTIVE REDUCTION OF THE G9A MRNA LEVELS IN THE HPC, WHILE HDAC-5 AND DNMT3A MRNA LEVELS WERE SPECIFICALLY REDUCED IN THE PFC.CONCLUSIONS: OVERALL, OUR RESULTS, SHOWING A DIFFERENT EXPRESSION OF BDNF TRANSCRIPTS AND EPIGENETIC MODIFYING ENZYMES IN SUSCEPTIBLE AND RESILIENT MICE, SUGGEST THAT STRESS RESILIENCE IS NOT SIMPLY A LACK OF ACTIVATION OF STRESS-RELATED PATHWAYS, BUT IS RELATED TO THE ACTIVATION OF ADDITIONAL DIFFERENT SPECIFIC MECHANISMS. 2019 4 1790 32 EFFECT OF CHRONIC MILD STRESS ON HIPPOCAMPAL TRANSCRIPTOME IN MICE SELECTED FOR HIGH AND LOW STRESS-INDUCED ANALGESIA AND DISPLAYING DIFFERENT EMOTIONAL BEHAVIORS. THERE IS INCREASING EVIDENCE THAT MOOD DISORDERS MAY DERIVE FROM THE IMPACT OF ENVIRONMENTAL PRESSURE ON GENETICALLY SUSCEPTIBLE INDIVIDUALS. STRESS-INDUCED HIPPOCAMPAL PLASTICITY HAS BEEN IMPLICATED IN DEPRESSION. WE STUDIED HIPPOCAMPAL TRANSCRIPTOMES IN STRAINS OF MICE THAT DISPLAY HIGH (HA) AND LOW (LA) SWIM STRESS-INDUCED ANALGESIA AND THAT DIFFER IN EMOTIONAL BEHAVIORS AND RESPONSES TO DIFFERENT CLASSES OF ANTIDEPRESSANTS. CHRONIC MILD STRESS (CMS) AFFECTED EXPRESSION OF A NUMBER OF GENES COMMON FOR BOTH STRAINS. CMS ALSO PRODUCED STRAIN SPECIFIC CHANGES IN EXPRESSION SUGGESTING THAT HIPPOCAMPAL RESPONSES TO STRESS DEPEND ON GENOTYPE. CONSIDERABLY LARGER NUMBER OF GENES, BIOLOGICAL PROCESSES, MOLECULAR FUNCTIONS, BIOCHEMICAL PATHWAYS, AND GENE NETWORKS WERE AFFECTED BY CMS IN LA THAN IN HA MICE. THE RESULTS SUGGEST THAT POTENTIAL DRUG TARGETS AGAINST DETRIMENTAL EFFECTS OF STRESS INCLUDE GLUTAMATE TRANSPORTERS, AND CHOLINERGIC, CHOLECYSTOKININ (CCK), GLUCOCORTICOIDS, AND THYROID HORMONES RECEPTORS. FURTHERMORE, SOME BIOLOGICAL PROCESSES EVOKED BY STRESS AND DIFFERENT BETWEEN THE STRAINS, SUCH AS APOPTOSIS, NEUROGENESIS AND CHROMATIN MODIFICATIONS, MAY BE RESPONSIBLE FOR THE LONG-TERM, IRREVERSIBLE EFFECTS OF STRESS AND SUGGEST A ROLE FOR EPIGENETIC REGULATION OF MOOD RELATED STRESS RESPONSES. 2011 5 432 26 ANTIDEPRESSANT TREATMENT IS ASSOCIATED WITH EPIGENETIC ALTERATIONS IN THE PROMOTER OF P11 IN A GENETIC MODEL OF DEPRESSION. P11 (S100A10) HAS BEEN ASSOCIATED WITH THE PATHOPHYSIOLOGY OF DEPRESSION BOTH IN HUMAN AND RODENT MODELS. DIFFERENT TYPES OF ANTIDEPRESSANTS HAVE BEEN SHOWN TO INCREASE P11 LEVELS IN DISTINCT BRAIN REGIONS AND P11 GENE THERAPY WAS RECENTLY PROVEN EFFECTIVE IN REVERSING DEPRESSIVE-LIKE BEHAVIOURS IN MICE. HOWEVER, THE MOLECULAR MECHANISMS THAT GOVERN P11 GENE EXPRESSION IN RESPONSE TO ANTIDEPRESSANTS STILL REMAIN ELUSIVE. IN THIS STUDY WE REPORT DECREASED LEVELS OF P11, ASSOCIATED WITH HIGHER DNA METHYLATION IN THE PROMOTER REGION, IN THE PREFRONTAL CORTEX OF THE FLINDERS SENSITIVE LINE (FSL) GENETIC RODENT MODEL OF DEPRESSION. THIS HYPERMETHYLATED PATTERN WAS REVERSED TO NORMAL, AS INDICATED BY THE CONTROL LINE, AFTER CHRONIC ADMINISTRATION OF ESCITALOPRAM (A SELECTIVE SEROTONIN REUPTAKE INHIBITOR; SSRI). THE ESCITALOPRAM-INDUCED HYPOMETHYLATION WAS ASSOCIATED WITH BOTH AN INCREASE IN P11 GENE EXPRESSION AND A REDUCTION IN MRNA LEVELS OF TWO DNA METHYLTRANSFERASES THAT HAVE BEEN SHOWN TO MAINTAIN DNA METHYLATION IN ADULT FOREBRAIN NEURONS (DNMT1 AND DNMT3A). IN CONCLUSION, OUR DATA FURTHER SUPPORT A ROLE FOR P11 IN DEPRESSION-LIKE STATES AND SUGGEST THAT THIS GENE IS CONTROLLED BY EPIGENETIC MECHANISMS THAT CAN BE AFFECTED BY ANTIDEPRESSANT TREATMENT. 2012 6 4093 32 MATERNAL SEPARATION FOLLOWED BY CHRONIC MILD STRESS IN ADULTHOOD IS ASSOCIATED WITH CONCERTED EPIGENETIC REGULATION OF AP-1 COMPLEX GENES. DEPRESSION IS ONE OF THE MOST PREVALENT MENTAL DISEASES WORLDWIDE. PATIENTS WITH PSYCHIATRIC DISEASES OFTEN HAVE A HISTORY OF CHILDHOOD NEGLECT, INDICATING THAT EARLY-LIFE EXPERIENCES PREDISPOSE TO PSYCHIATRIC DISEASES IN ADULTHOOD. TWO STRONG MODELS WERE USED IN THE PRESENT STUDY: THE MATERNAL SEPARATION/EARLY DEPRIVATION MODEL (MS) AND THE CHRONIC MILD STRESS MODEL (CMS). IN BOTH MODELS, WE FOUND CHANGES IN THE EXPRESSION OF A NUMBER OF GENES SUCH AS CREB AND NPY. STRIKINGLY, THERE WAS A CLEAR REGULATION OF EXPRESSION OF FOUR GENES INVOLVED IN THE AP-1 COMPLEX: C-FOS, C-JUN, FOSB, AND JUN-B. INTERESTINGLY, DIFFERENT EXPRESSION LEVELS WERE OBSERVED DEPENDING ON THE MODEL, WHEREAS THE COMBINATION OF THE MODELS RESULTED IN A NORMAL LEVEL OF GENE EXPRESSION. THE EFFECTS OF MS AND CMS ON GENE EXPRESSION WERE ASSOCIATED WITH DISTINCT HISTONE METHYLATION/ACETYLATION PATTERNS OF ALL FOUR GENES. THE EPIGENETIC CHANGES, LIKE GENE EXPRESSION, WERE ALSO DEPENDENT ON THE SPECIFIC STRESSOR OR THEIR COMBINATION. THE OBTAINED RESULTS SUGGEST THAT SINGLE LIFE EVENTS LEAVE A MARK ON GENE EXPRESSION AND THE EPIGENETIC SIGNATURE OF GENE PROMOTERS, BUT A COMBINATION OF DIFFERENT STRESSORS AT DIFFERENT LIFE STAGES CAN FURTHER CHANGE GENE EXPRESSION THROUGH EPIGENETIC FACTORS, POSSIBLY CAUSING THE LONG-LASTING ADVERSE EFFECTS OF STRESS. 2021 7 3328 29 HISTONE DEACETYLASE 5 MODULATES THE EFFECTS OF SOCIAL ADVERSITY IN EARLY LIFE ON COCAINE-INDUCED BEHAVIOR. PSYCHOSTIMULANTS INDUCE STABLE CHANGES IN NEURAL PLASTICITY AND BEHAVIOR IN A TRANSCRIPTION-DEPENDENT MANNER. FURTHER, STABLE CELLULAR CHANGES REQUIRE TRANSCRIPTION THAT IS REGULATED BY EPIGENETIC MECHANISMS THAT ALTER CHROMATIN STRUCTURE, SUCH AS HISTONE ACETYLATION. THIS MECHANISM IS TYPICALLY CATALYZED BY ENZYMES WITH HISTONE ACETYLTRANSFERASE OR HISTONE DEACETYLASE (HDAC) ACTIVITY. CLASS IIA HDACS ARE NOTABLE FOR THEIR HIGH EXPRESSION IN IMPORTANT REGIONS OF THE BRAIN REWARD CIRCUITRY AND THEIR NEURAL ACTIVITY-DEPENDENT SHUTTLING IN AND OUT OF THE CELL NUCLEUS. IN PARTICULAR, HDAC5 HAS AN IMPORTANT MODULATORY FUNCTION IN COCAINE-INDUCED BEHAVIORS AND SOCIAL DEFEAT STRESS-INDUCED EFFECTS. ALTHOUGH A MUTATION IN HDAC5 HAS BEEN SHOWN TO CAUSE HYPERSENSITIVE RESPONSES TO CHRONIC COCAINE USE WHETHER THIS RESPONSE WORSENS DURING CHRONIC EARLY LIFE STRESS HAS NOT BEEN EXAMINED YET. IN THIS STUDY, WE EXPOSED MOUSE PUPS TO TWO DIFFERENT EARLY LIFE STRESS PARADIGMS (SOCIAL ISOLATION, ESI, AND SOCIAL THREAT, EST) TO DETERMINE WHETHER THE HETEROZYGOUS NULL MUTATION IN HDAC5 (HDAC5+/-) MODERATED THE EFFECTS OF EXPOSURE TO STRESS IN EARLY LIFE ON ADULT COCAINE-INDUCED CONDITIONED PLACE PREFERENCE (CPP). NOTABLY, HDAC5+/- MICE THAT HAD BEEN EXPOSED TO ESI WERE MORE SUSCEPTIBLE TO DEVELOPING COCAINE-INDUCED CPP AND MORE RESISTANT TO EXTINGUISHING THIS BEHAVIOR. THE SAME EFFECT WAS NOT OBSERVED FOR HDAC5+/- MICE EXPERIENCING EST, SUGGESTING THAT ONLY ESI INDUCES BEHAVIORAL CHANGES BY ACTING PRECISELY THROUGH HDAC5-RELATED BIOLOGICAL PATHWAYS. FINALLY, AN ANALYSIS OF C-FOS EXPRESSION PERFORMED TO DISCOVER THE NEUROBIOLOGICAL SUBSTRATES THAT MEDIATED THIS PHENOTYPE, IDENTIFIED THE DORSOLATERAL STRIATUM AS AN IMPORTANT STRUCTURE THAT MEDIATES THE INTERACTION BETWEEN HDAC5 MUTATION AND ESI. OUR DATA DEMONSTRATE THAT DECREASED HDAC5 FUNCTION IS ABLE TO EXACERBATE THE LONG-TERM BEHAVIORAL EFFECTS OF ADVERSE REARING ENVIRONMENT IN MOUSE. 2017 8 3093 25 GENOMIC AND EPIGENOMIC RESPONSES TO CHRONIC STRESS INVOLVE MIRNA-MEDIATED PROGRAMMING. STRESS REPRESENTS A CRITICAL INFLUENCE ON MOTOR SYSTEM FUNCTION AND HAS BEEN SHOWN TO IMPAIR MOVEMENT PERFORMANCE. WE HYPOTHESIZED THAT STRESS-INDUCED MOTOR IMPAIRMENTS ARE DUE TO BRAIN-SPECIFIC CHANGES IN MIRNA AND PROTEIN-ENCODING GENE EXPRESSION. HERE WE SHOW A CAUSAL LINK BETWEEN STRESS-INDUCED MOTOR IMPAIRMENT AND ASSOCIATED GENETIC AND EPIGENETIC RESPONSES IN RELEVANT CENTRAL MOTOR AREAS IN A RAT MODEL. EXPOSURE TO TWO WEEKS OF MILD RESTRAINT STRESS ALTERED THE EXPRESSION OF 39 GENES AND NINE MIRNAS IN THE CEREBELLUM. IN LINE WITH PERSISTENT BEHAVIOURAL IMPAIRMENTS, SOME CHANGES IN GENE AND MIRNA EXPRESSION WERE RESISTANT TO RECOVERY FROM STRESS. INTERESTINGLY, STRESS UP-REGULATED THE EXPRESSION OF ADIPOQ AND PROLACTIN RECEPTOR MRNAS IN THE CEREBELLUM. STRESS ALSO ALTERED THE EXPRESSION OF PRLR, MIR-186, AND MIR-709 IN HIPPOCAMPUS AND PREFRONTAL CORTEX. IN ADDITION, OUR FINDINGS DEMONSTRATE THAT MIR-186 TARGETS THE GENE EPS15. FURTHERMORE, WE FOUND AN AGE-DEPENDENT INCREASE IN EPHRINB3 AND GABAA4 RECEPTORS. THESE DATA SHOW THAT EVEN MILD STRESS RESULTS IN SUBSTANTIAL GENOMIC AND EPIGENOMIC CHANGES INVOLVING MIRNA EXPRESSION AND ASSOCIATED GENE TARGETS IN THE MOTOR SYSTEM. THESE FINDINGS SUGGEST A CENTRAL ROLE OF MIRNA-REGULATED GENE EXPRESSION IN THE STRESS RESPONSE AND IN ASSOCIATED NEUROLOGICAL FUNCTION. 2012 9 2740 26 EXPOSURE TO EARLY LIFE STRESS RESULTS IN EPIGENETIC CHANGES IN NEUROTROPHIC FACTOR GENE EXPRESSION IN A PARKINSONIAN RAT MODEL. EARLY LIFE ADVERSITY INCREASES THE RISK OF MENTAL DISORDERS LATER IN LIFE. CHRONIC EARLY LIFE STRESS MAY ALTER NEUROTROPHIC FACTOR GENE EXPRESSION INCLUDING THOSE FOR BRAIN DERIVED NEUROTROPHIC FACTOR (BDNF) AND GLIAL CELL DERIVED NEUROTROPHIC FACTOR (GDNF) THAT ARE IMPORTANT IN NEURONAL GROWTH, SURVIVAL, AND MAINTENANCE. MATERNAL SEPARATION WAS USED IN THIS STUDY TO MODEL EARLY LIFE STRESS. FOLLOWING UNILATERAL INJECTION OF A MILD DOSE OF 6-HYDROXYDOPAMINE (6-OHDA), WE MEASURED CORTICOSTERONE (CORT) IN THE BLOOD AND STRIATUM OF STRESSED AND NONSTRESSED RATS; WE ALSO MEASURED DNA METHYLATION AND BDNF AND GDNF GENE EXPRESSION IN THE STRIATUM USING REAL TIME PCR. IN THE PRESENCE OF STRESS, WE FOUND THAT THERE WAS INCREASED CORTICOSTERONE CONCENTRATION IN BOTH BLOOD AND STRIATAL TISSUE. FURTHER TO THIS, WE FOUND HIGHER DNA METHYLATION AND DECREASED NEUROTROPHIC FACTOR GENE EXPRESSION. 6-OHDA LESION INCREASED NEUROTROPHIC FACTOR GENE EXPRESSION IN BOTH STRESSED AND NONSTRESSED RATS BUT THIS INCREASE WAS HIGHER IN THE NONSTRESSED RATS. OUR RESULTS SUGGEST THAT EXPOSURE TO EARLY POSTNATAL STRESS INCREASES CORTICOSTERONE CONCENTRATION WHICH LEADS TO INCREASED DNA METHYLATION. THIS EFFECT RESULTS IN DECREASED BDNF AND GDNF GENE EXPRESSION IN THE STRIATUM LEADING TO DECREASED PROTECTION AGAINST SUBSEQUENT INSULTS LATER IN LIFE. 2016 10 1823 23 EFFECTS OF EARLY-LIFE STRESS AND HDAC INHIBITION ON MATERNAL BEHAVIOR IN MICE. DESPITE THE WELL-ESTABLISHED FACT THAT MATERNAL CARE PLAYS A PIVOTAL ROLE IN THE OFFSPRING DEVELOPMENT, LITTLE IS KNOWN ABOUT THE EFFECTS OF DISRUPTION OF MATERNAL CARE EARLY IN LIFE ON THE DEVELOPMENT OF THIS BEHAVIOR IN THE OFFSPRING. USING BRIEF REPEATED MATERNAL SEPARATION (45 MIN/DAY ON POSTNATAL DAYS 3-6), WHICH REPRESENTS A MODEL OF EARLY LIFE STRESS, WE FOUND BEHAVIORAL CHANGES IN ADULT FEMALE MICE OFFSPRING. THE DECREASE IN HOME CAGE EXPLORATORY BEHAVIOR (BOTH PUP-DIRECTED AND NONPUP-DIRECTED) WAS REVEALED LATER IN ADULTHOOD WITHOUT CHANGES IN MATERNAL CARE LEVEL. MATERNAL SEPARATION COUPLED WITH PAIN EXPOSURE CAUSED BY SUBCUTANEOUS SALINE INJECTION PROCEDURE HAD A CUMULATIVE RESULTING EFFECT, WHICH WAS MANIFESTED IN THE DECREASED LEVEL OF NURSING ASSOCIATED WITH LICKING-GROOMING IN ADULT FEMALES. THE BEHAVIORAL CHANGES FOUND IN ADULT FEMALE OFFSPRING COULD BE TRIGGERED BY IDENTIFIED CHANGES IN THE BEHAVIOR OF THEIR MOTHERS, WHILE ALTERATIONS OF THE LEVEL OF HISTONE H3 ACETYLATION IN THE NEONATAL BRAIN WERE NOT DETECTED. HISTONE DEACETYLASE INHIBITOR SODIUM VALPROATE WAS USED IN ORDER TO STUDY THE POSSIBILITY OF PREVENTING THE EFFECTS OF EARLY LIFE STRESS THROUGH INVOLVEMENT OF EPIGENETIC MECHANISMS. DESPITE THE INCREASE IN THE LEVEL OF HISTONE H3 ACETYLATION IN THE NEONATAL BRAIN CAUSED BY VALPROATE, ITS BEHAVIORAL EFFECTS WERE BARELY DETECTABLE. THESE EFFECTS WERE REFLECTED IN PREVENTION OF THE REDUCTION OF NURSING ASSOCIATED WITH LICKING-GROOMING INDUCED BY MATERNAL SEPARATION, ACCOMPANIED BY PAIN EXPOSURE. THE DATA ARE DISCUSSED IN TERMS OF THE POSSIBLE APPLICATION TO THE STUDIES OF MECHANISMS UNDERLYING LONG-TERM EFFECTS OF HUMAN EARLY LIFE TRAUMA. (PSYCINFO DATABASE RECORD (C) 2019 APA, ALL RIGHTS RESERVED). 2019 11 6804 33 [EPIGENETIC REGULATION IN DEPRESSION]. RECENT RESEARCH HAS RAISED THE NOTION THAT EPIGENETIC MECHANISMS (E.G., DNA METHYLATION AND HISTONE MODIFICATIONS), WHICH EXERT LASTING CONTROL OVER GENE EXPRESSION WITHOUT ALTERING THE GENETIC CODE, COULD MEDIATE STABLE CHANGES IN BRAIN FUNCTION. HOWEVER, THE ROLE OF ENVIRONMENTAL FACTORS ALONG WITH GENETIC FACTORS IN THE EPIGENETIC REGULATION OF THE PATHOGENESIS OF DEPRESSION IS LARGELY UNKNOWN. TWO GENETICALLY DISTINCT MICE STRAINS, BALB/C (BALB) AND C57BL/6 (B6), EXHIBIT DIFFERENT BEHAVIORAL RESPONSES TO CHRONIC STRESS. WITH CHRONIC STRESS, BALB MICE SHOWED DEPRESSIVE-LIKE BEHAVIORS, BUT NOT B6 MICE, AND GLIAL CELL-DERIVED NEUROTROPHIC FACTOR (GDNF) EXPRESSION LEVEL WAS DECREASED IN THE VENTRAL STRIATUM OF BALB MICE BUT INCREASED IN B6 MICE. IN BALB MICE, DEPRESSIVE-LIKE BEHAVIORS AND DECREASED GDNF EXPRESSION WERE RECOVERED BY CHRONIC ANTIDEPRESSANT TREATMENT. THEREFORE, WE USED THESE TWO MICE STRAINS TO INVESTIGATE HOW THE EPIGENETIC STATUS OF THE GDNF GENE IN THE VENTRAL STRIATUM MODULATES STRESS VULNERABILITY. BOTH MICE STRAINS SHOWED INCREASED DNA METHYLATION LEVELS AND MECP2 RECRUITMENT IN THE GDNF PROMOTER REGION. HOWEVER, HISTONE H3 ACETYLATION LEVEL WAS DECREASED IN BALB MICE, BUT INCREASED IN B6 MICE. FURTHERMORE, BALB MICE SHOWED INCREASED HISTONE DEACETYLASE2 (HDAC2) EXPRESSION LEVEL AND RE-CHIP ASSAY REVEALED HDAC2-MECP2 COMPLEX IN BALB MICE. OUR RESULTS INDICATE THE CRUCIAL ROLE OF HISTONE MODIFICATION BY HDAC2 AND MECP2 COMPLEX FOR THE CONTROL OF GDNF EXPRESSION AND SUBSEQUENT BEHAVIORAL RESPONSES TO CHRONIC STRESS, IN OTHER WORDS, THE SUSCEPTIBILITY TO STRESS. IN ADDITION, WE INVESTIGATED THE EFFECT OF ANTIDEPRESSANTS ON THE EPIGENETIC REGULATION OF GDNF EXPRESSION. WE FOUND A REDUCED LEVEL OF HDAC4 RECRUITMENT AT THE GDNF PROMOTER REGION WITH ANTIDEPRESSANTS. THUS, OUR DATA SUGGEST THAT ANTIDEPRESSANTS INCREASE TRANSCRIPTIONAL ACTIVITY OF THE GDNF GENE THROUGH THE MODULATION OF HISTONE ACETYLATION BY HDAC4. FINALLY, WE EXAMINED THE EXPRESSIONS OF GDNF AND EPIGENETIC-RELATED MOLECULES MRNAS WITH MAJOR DEPRESSIVE AND BIPOLAR DISORDER PATIENTS BY USING QUANTITATIVE REAL-TIME PCR. WE FOUND THE ABERRANT EXPRESSION OF GDNF AND EPIGENETIC-RELATED GENES INCLUDING HDAC2 AND HDAC4 IN MOOD DISORDER PATIENTS. THUS, OUR DATA PROVIDE NOVEL INSIGHTS SUGGESTING THAT EPIGENETIC MECHANISMS OF GDNF EXPRESSION ARE INVOLVED IN THE PATHOGENESIS OR PATHOPHYSIOLOGY OF DEPRESSION. 2012 12 1418 32 DIFFERENCES IN DNA METHYLATION REPROGRAMMING UNDERLIE THE SEXUAL DIMORPHISM OF BEHAVIORAL DISORDER CAUSED BY PRENATAL STRESS IN RATS. PRENATAL STRESS (PS) CAN LEAD TO NEUROENDOCRINE AND EMOTIONAL DISORDERS LATER IN ADOLESCENCE. SEXUAL DIMORPHISM IN THESE NEURODEVELOPMENTAL OUTCOMES HAVE BEEN OBSERVED; HOWEVER, THE UNDERLYING MECHANISMS ARE NOT FULLY UNDERSTOOD. TO ADDRESS THIS ISSUE, WE INVESTIGATED WHETHER THERE ARE SEX DIFFERENCES IN EPIGENETIC REPROGRAMMING IN RATS EXPOSED TO PS. PREGNANT FEMALE RATS WERE SUBJECTED TO CHRONIC RESTRAINT STRESS FROM GESTATIONAL DAY (G)12 TO G18. FROM POSTNATAL DAY (P)38 TO P45, SUBGROUPS OF OFFSPRING INCLUDING BOTH MALES AND FEMALES WERE SUBJECTED TO BEHAVIORAL TESTING AND BRAIN TISSUE SPECIMENS WERE ANALYZED BY DNA PYROSEQUENCING, WESTERN BLOTTING, AND GOLGI STAINING TO ASSESS CHANGES IN METHYLATION PATTERN OF GLUCOCORTICOID RECEPTOR (GR) GENE, EXPRESSION OF DNA METHYLTRANSFERASE (DNMT) AND DNA DEMETHYLASE, AND DENDRITE MORPHOLOGY, RESPECTIVELY. THE DNA METHYLTRANSFERASE INHIBITOR DECITABINE WAS ADMINISTERED TO RATS PRIOR TO PS TO FURTHER EVALUATE THE ROLE OF METHYLATION IN THE SEXUALLY DIMORPHIC EFFECTS OF PS. THE RESULTS SHOWED THAT PS INCREASED ANXIETY-LIKE BEHAVIOR IN OFFSPRING, ESPECIALLY IN FEMALES, WHILE DEPRESSION-LIKE BEHAVIOR WAS INCREASED IN MALE OFFSPRING COMPARED TO CONTROL LITTERMATES. THE METHYLATION PATTERN IN THE PROMOTER REGION OF THE GR GENE DIFFERED BETWEEN MALES AND FEMALES. SEX-SPECIFIC CHANGES IN THE EXPRESSION OF DNMTS (DNMT1 AND DNMT3A) AND DNA DEMETHYLASE (TET METHYLCYTOSINE DIOXYGENASE 2) WERE ALSO OBSERVED. INTERESTINGLY, DECITABINE ALLEVIATED THE BEHAVIORAL DISORDER CAUSED BY PS AND RESTORED DENDRITE DENSITY AND MORPHOLOGY IN FEMALE BUT NOT MALE RATS. THESE FINDINGS SUGGEST THAT DIFFERENT CHANGE PATTERNS OF DNMT AND DEMETHYLASE IN THE TWO SEXES AFTER PS ARE RESPONSIBLE FOR THE SEXUALLY DIMORPHISM, WHICH COULD HAVE IMPLICATIONS FOR THE CLINICAL MANAGEMENT OF STRESS-RELATED DISORDERS. 2020 13 6895 19 [SYSTEMIC CONTROL OF THE MOLECULAR, CELL, AND EPIGENETIC MECHANISMS OF LONG-LASTING CONSEQUENCES OF STRESS]. BASED ON M.E. LOBASHEV'S VIEWS OF THE SYSTEMIC CONTROL OF GENETIC AND CYTOGENEITC PROCESSES AND A SUBSTANTIAL EFFECT OF EXCITABILITY ON PLASTIC CHANGES IN THE CENTRAL NERVOUS SYSTEM (CNS), THE EFFECT OF PROLONGED EMOTIONAL AND PAIN STRESS (PEPS) ON THE MOLECULAR, CELL, AND EPIGENETIC MECHANISMS OF INJURY MEMORY WAS STUDIED IN RAT STRAINS BRED FOR A CERTAIN EXCITABILITY OF THE NERVOUS SYSTEM. PEPS WAS FOR THE FIRST TIME FOUND TO CAUSE LONG-LASTING (2 MONTHS) MORPHOLOGICAL ALTERATIONS OF THE CA3 REGION OF THE HIPPOCAMPUS AND TO MODIFY THE GENOME ACTIVITY OF ITS PYRAMIDAL NEURONS. THE TWO PHENOMENA WERE POTENTIATED BY A GENETICALLY DETERMINED LOW FUNCTIONAL STATE OF THE CNS. THE POST-STRESS REGULATION OF THE GENOME FUNCTION IN HIPPOCAMPAL NEURONS WAS MEDIATED BY CHANGES IN HETEROCHROMATIN CONFORMATION, ACTIVATION OF METHYL-CPG-BINDING PROTEIN (MECP2) SYNTHESIS, AND SUBSEQUENT CHANGES IN ACETYLATION OF HISTONE H4. GENETICALLY DETERMINED HIGH EXCITABILITY OF THE NERVOUS SYSTEM PROVED TO BE A RISK FACTOR THAT AFFECTS THE SPECIFICS AND TIME COURSE OF THE OBSERVED MOLECULAR, CELL, AND GENETIC TRANSFORMATIONS OF NEURONS. THE RESULTS PROVIDE FOR A BETTER UNDERSTANDING OF THE EPIGENETIC MECHANISMS OF INJURY MEMORY, WHICH FORMS A PATHOGENETIC BASIS FOR POSTTRAUMATIC STRESS DISORDER AND OTHER HUMAN PSYCHOGENIC CONDITIONS CHARACTERIZED BY A PROLONGED DURATION. 2009 14 5219 29 PREVIOUS HISTORY OF CHRONIC STRESS CHANGES THE TRANSCRIPTIONAL RESPONSE TO GLUCOCORTICOID CHALLENGE IN THE DENTATE GYRUS REGION OF THE MALE RAT HIPPOCAMPUS. CHRONIC STRESS IS A RISK FACTOR FOR SEVERAL NEUROPSYCHIATRIC DISEASES, SUCH AS DEPRESSION AND PSYCHOSIS. IN RESPONSE TO STRESS GLUCOCORTICOIDS (GCS) ARE SECRETED THAT BIND TO MINERALOCORTICOID AND GLUCOCORTICOID RECEPTORS, LIGAND-ACTIVATED TRANSCRIPTION FACTORS THAT REGULATE THE TRANSCRIPTION OF GENE NETWORKS IN THE BRAIN NECESSARY FOR COPING WITH STRESS, RECOVERY, AND ADAPTATION. CHRONIC STRESS PARTICULARLY AFFECTS THE DENTATE GYRUS (DG) SUBREGION OF THE HIPPOCAMPUS, CAUSING SEVERAL FUNCTIONAL AND MORPHOLOGICAL CHANGES WITH CONSEQUENCES FOR LEARNING AND MEMORY, WHICH ARE LIKELY ADAPTIVE BUT AT THE SAME TIME MAKE DG NEURONS MORE VULNERABLE TO SUBSEQUENT CHALLENGES. THE AIM OF THIS STUDY WAS TO INVESTIGATE THE TRANSCRIPTIONAL RESPONSE OF DG NEURONS TO A GC CHALLENGE IN MALE RATS PREVIOUSLY EXPOSED TO CHRONIC RESTRAINT STRESS (CRS). AN INTRIGUING FINDING OF THE CURRENT STUDY WAS THAT HAVING A HISTORY OF CRS HAD PROFOUND CONSEQUENCES FOR THE SUBSEQUENT RESPONSE TO ACUTE GC CHALLENGE, DIFFERENTIALLY AFFECTING THE EXPRESSION OF SEVERAL HUNDREDS OF GENES IN THE DG COMPARED WITH CHALLENGED NONSTRESSED CONTROL ANIMALS. THIS ENDURING EFFECT OF PREVIOUS STRESS EXPOSURE SUGGESTS THAT EPIGENETIC PROCESSES MAY BE INVOLVED. IN LINE WITH THIS, CRS INDEED AFFECTED THE EXPRESSION OF SEVERAL GENES INVOLVED IN CHROMATIN STRUCTURE AND EPIGENETIC PROCESSES, INCLUDING ASF1, ASH1L, HIST1H3F, AND TP63. THE DATA PRESENTED HERE INDICATE THAT CRS ALTERS THE TRANSCRIPTIONAL RESPONSE TO A SUBSEQUENT GC INJECTION. WE PROPOSE THAT THIS ALTERED TRANSCRIPTIONAL POTENTIAL FORMS PART OF THE MOLECULAR MECHANISM UNDERLYING THE ENHANCED VULNERABILITY FOR STRESS-RELATED DISORDERS LIKE DEPRESSION CAUSED BY CHRONIC STRESS. 2013 15 3714 28 INHERITANCE OF SOCIAL DOMINANCE IS ASSOCIATED WITH GLOBAL SPERM DNA METHYLATION IN INBRED MALE MICE. DOMINANCE RELATIONSHIPS BETWEEN MALES AND THEIR ASSOCIATED TRAITS ARE USUALLY HERITABLE AND HAVE IMPLICATIONS FOR SEXUAL SELECTION IN ANIMALS. IN PARTICULAR, SOCIAL DOMINANCE AND ITS RELATED MALE PHEROMONES ARE HERITABLE IN INBRED MICE; THUS, WE WONDERED WHETHER EPIGENETIC CHANGES DUE TO ALTERED LEVELS OF DNA METHYLATION DETERMINE INHERITANCE. HERE, WE USED C57BL/6 MALE MICE TO ESTABLISH A SOCIAL DOMINANCE-SUBORDINATION RELATIONSHIP THROUGH CHRONIC DYADIC ENCOUNTERS, AND THIS RELATIONSHIP AND PHEROMONE COVARIATION OCCURRED IN THEIR OFFSPRING, INDICATIVE OF HERITABILITY. THROUGH TRANSCRIPTOME SEQUENCING AND WHOLE-GENOME DNA METHYLATION PROFILING OF THE SPERM OF BOTH GENERATIONS, WE FOUND THAT DIFFERENTIAL METHYLATION OF MANY GENES WAS INDUCED BY SOCIAL DOMINANCE-SUBORDINATION IN SIRES AND COULD BE PASSED ON TO THE OFFSPRING. THESE METHYLATED GENES WERE MAINLY RELATED TO GROWTH AND DEVELOPMENT PROCESSES, NEURODEVELOPMENT, AND CELLULAR TRANSPORTATION. THE EXPRESSION OF THE GENES WITH SIMILAR FUNCTIONS IN WHOLE-GENOME METHYLATION/BISULFITE SEQUENCING WAS ALSO DIFFERENTIATED BY SOCIAL DOMINANCE-SUBORDINATION, AS REVEALED BY RNA-SEQ. IN PARTICULAR, THE GENE DENND1A, WHICH REGULATES NEURAL SIGNALING, WAS DIFFERENTIALLY METHYLATED AND EXPRESSED IN THE SPERM AND MEDIAL PREFRONTAL CORTEX IN PAIRED MALES BEFORE AND AFTER DOMINANCE-SUBORDINATION ESTABLISHMENT, SUGGESTING THE POTENTIAL EPIGENETIC CONTROL AND INHERITANCE OF SOCIAL DOMINANCE-RELATED AGGRESSION. WE SUGGEST THAT SOCIAL DOMINANCE MIGHT BE PASSED ON TO MALE OFFSPRING THROUGH SPERM DNA METHYLATION AND THAT THE DIFFERENCES COULD POTENTIALLY AFFECT MALE COMPETITION IN OFFSPRING BY AFFECTING THE DEVELOPMENT OF THE NERVOUS SYSTEM. 2023 16 1820 27 EFFECTS OF CHRONIC RESTRAINT STRESS ON THE GLOBAL DNA METHYLATION PROFILE OF RAT LUNG CELLS: MODULATION BY PHYSICAL EXERCISE. THE POTENTIAL OF BEHAVIORAL STRESS TO AFFECT EPIGENETIC MECHANISMS OF NON-ENCEPHALIC TISSUES IS STILL UNDERESTIMATED. IN THE PRESENT STUDY WE EVALUATED THE EFFECTS OF CHRONIC BEHAVIORAL STRESS ON THE DNA METHYLATION PROFILE OF RAT LUNG CELLS. FURTHERMORE, WE EVALUATED THE POTENTIAL OF PHYSICAL EXERCISE TO MODULATE THE CHANGES EVOKED BY BEHAVIORAL STRESS IN LUNG CELLS. MALE WISTAR RATS WERE DIVIDED INTO FOUR EXPERIMENTAL GROUPS: (1) ANIMALS SUBMITTED TO CHRONIC RESTRAINT STRESS (CRS) (ST GROUP) DURING THE PERIOD OF THE 67TH-80TH POSTNATAL DAY (PND); (2) ANIMALS SUBMITTED TO PHYSICAL EXERCISE (EX GROUP) DURING THE 53RD-79TH PND; (3) ANIMALS SUBMITTED TO SWIMMING DURING THE 53RD-79TH PND AND TO CRS DURING THE 67TH-80TH PND (EX-ST GROUP); AND (4) ANIMALS NOT SUBMITTED TO STRESS OR SWIMMING PROTOCOLS (CTL). GLOBAL DNA METHYLATION WAS QUANTIFIED USING AN ELISA-BASED APPROACH AND GENE EXPRESSION WAS EVALUATED BY REAL TIME PCR. A DECREASED GLOBAL DNA METHYLATION PROFILE WAS OBSERVED IN THE ST GROUP, HOWEVER PHYSICAL EXERCISE DEMONSTRATED PROTECTION OF LUNG CELLS FROM THIS STRESS-RELATED HYPOMETHYLATION. INCREASED EXPRESSION OF THE DNMT1 GENE WAS EVIDENCED IN THE ST GROUP, WHEREAS PHYSICAL EXERCISE WAS SHOWN TO PROTECT LUNG CELLS FROM THIS STRESS-RELATED EFFECT IN THE EX-ST GROUP. COMPARATIVE ANALYSIS OF THE ST AND EX GROUPS REVEALED OPPOSITE EFFECTS ON THE EXPRESSION OF DNMT3A AND DNMT3B; HOWEVER, A STRESS-RELATED INCREASE IN EXPRESSION OF DNMT3A AND DNMT3B WAS NOT SEEN IN THE EX-ST GROUP. OUR DATA SHOWED THAT BEHAVIORAL STRESS INDUCED SIGNIFICANT CHANGES IN THE DNA METHYLATION PROFILE OF RAT LUNG CELLS AND THAT THIS COULD BE MODULATED BY PHYSICAL EXERCISE. 2017 17 4405 30 MOLECULAR ADAPTATIONS OF THE BLOOD-BRAIN BARRIER PROMOTE STRESS RESILIENCE VS. DEPRESSION. PRECLINICAL AND CLINICAL STUDIES SUGGEST THAT INFLAMMATION AND VASCULAR DYSFUNCTION CONTRIBUTE TO THE PATHOGENESIS OF MAJOR DEPRESSIVE DISORDER (MDD). CHRONIC SOCIAL STRESS ALTERS BLOOD-BRAIN BARRIER (BBB) INTEGRITY THROUGH LOSS OF TIGHT JUNCTION PROTEIN CLAUDIN-5 (CLDN5) IN MALE MICE, PROMOTING PASSAGE OF CIRCULATING PROINFLAMMATORY CYTOKINES AND DEPRESSION-LIKE BEHAVIORS. THIS EFFECT IS PROMINENT WITHIN THE NUCLEUS ACCUMBENS, A BRAIN REGION ASSOCIATED WITH MOOD REGULATION; HOWEVER, THE MECHANISMS INVOLVED ARE UNCLEAR. MOREOVER, COMPENSATORY RESPONSES LEADING TO PROPER BEHAVIORAL STRATEGIES AND ACTIVE RESILIENCE ARE UNKNOWN. HERE WE IDENTIFY ACTIVE MOLECULAR CHANGES WITHIN THE BBB ASSOCIATED WITH STRESS RESILIENCE THAT MIGHT SERVE A PROTECTIVE ROLE FOR THE NEUROVASCULATURE. WE ALSO CONFIRM THE RELEVANCE OF SUCH CHANGES TO HUMAN DEPRESSION AND ANTIDEPRESSANT TREATMENT. WE SHOW THAT PERMISSIVE EPIGENETIC REGULATION OF CLDN5 EXPRESSION AND LOW ENDOTHELIUM EXPRESSION OF REPRESSIVE CLDN5-RELATED TRANSCRIPTION FACTOR FOXO1 ARE ASSOCIATED WITH STRESS RESILIENCE. REGION- AND ENDOTHELIAL CELL-SPECIFIC WHOLE TRANSCRIPTOMIC ANALYSES REVEALED MOLECULAR SIGNATURES ASSOCIATED WITH STRESS VULNERABILITY VS. RESILIENCE. WE IDENTIFIED PROINFLAMMATORY TNFALPHA/NFKAPPAB SIGNALING AND HDAC1 AS MEDIATORS OF STRESS SUSCEPTIBILITY. PHARMACOLOGICAL INHIBITION OF STRESS-INDUCED INCREASE IN HDAC1 ACTIVITY RESCUED CLDN5 EXPRESSION IN THE NAC AND PROMOTED RESILIENCE. IMPORTANTLY, WE CONFIRMED CHANGES IN HDAC1 EXPRESSION IN THE NAC OF DEPRESSED PATIENTS WITHOUT ANTIDEPRESSANT TREATMENT IN LINE WITH CLDN5 LOSS. CONVERSELY, MANY OF THESE DELETERIOUS CLDN5-RELATED MOLECULAR CHANGES WERE REDUCED IN POSTMORTEM NAC FROM ANTIDEPRESSANT-TREATED SUBJECTS. THESE FINDINGS REINFORCE THE IMPORTANCE OF CONSIDERING STRESS-INDUCED NEUROVASCULAR PATHOLOGY IN DEPRESSION AND PROVIDE THERAPEUTIC TARGETS TO TREAT THIS MOOD DISORDER AND PROMOTE RESILIENCE. 2020 18 2119 26 EPIGENETIC HISTONE MODIFICATION REGULATES DEVELOPMENTAL LEAD EXPOSURE INDUCED HYPERACTIVITY IN RATS. LEAD (PB) EXPOSURE WAS COMMONLY CONSIDERED AS A HIGH ENVIRONMENTAL RISK FACTOR FOR THE DEVELOPMENT OF ATTENTION-DEFICIT/HYPERACTIVITY DISORDER (ADHD). HOWEVER, THE MOLECULAR BASIS OF THIS PATHOLOGICAL PROCESS STILL REMAINS ELUSIVE. IN LIGHT OF THE ROLE OF EPIGENETICS IN MODULATING THE NEUROLOGICAL DISEASE AND THE CAUSATIVE ENVIRONMENT, THE ALTERATIONS OF HISTONE MODIFICATIONS IN THE HIPPOCAMPUS OF RATS EXPOSED BY VARIOUS DOSES OF LEAD, ALONG WITH CONCOMITANT BEHAVIORAL DEFICITS, WERE INVESTIGATED IN THIS STUDY. ACCORDING TO THE FREE AND FORCED OPEN FIELD TEST, THERE SHOWED THAT IN A DOSAGE-DEPENDENT MANNER, LEAD EXPOSURE COULD RESULT IN THE INCREASED LOCOMOTOR ACTIVITY OF RATS, THAT IS, HYPERACTIVITY: A SUBTYPE OF ADHD. WESTERN BLOTTING ASSAYS REVEALED THAT THE LEVELS OF HISTONE ACETYLATION INCREASED SIGNIFICANTLY IN THE HIPPOCAMPUS BY CHRONIC LEAD EXPOSURE, WHILE NO DRAMATIC CHANGES WERE DETECTED IN TERMS OF EXPRESSION YIELDS OF ADHD-RELATED DOPAMINERGIC PROTEINS, INDICATING THAT HISTONE ACETYLATION PLAYS ESSENTIAL ROLES IN THIS TOXICANT-INVOLVED PATHOGENESIS. IN ADDITION, THE INCREASED LEVEL OF HISTONE ACETYLATION MIGHT BE ATTRIBUTED TO THE ENZYMATIC ACTIVITY OF P300, A TYPICAL HISTONE ACETYLTRANSFERASE, AS THE TRANSCRIPTIONAL LEVEL OF P300 WAS SIGNIFICANTLY INCREASED UPON HIGHER-DOSE PB EXPOSURE. IN SUMMARY, THIS STUDY FIRST DISCOVERED THE EPIGENETIC MECHANISM BRIDGING THE ENVIRONMENTAL INFLUENCE (PB) AND THE DISEASE ITSELF (ADHD) IN THE HISTONE MODIFICATION LEVEL, PAVING THE WAY FOR THE COMPREHENSIVE UNDERSTANDING OF ADHD'S ETIOLOGY AND IN FURTHER STEPS, ESTABLISHING THE THERAPY STRATEGY OF THIS WIDESPREAD NEUROLOGICAL DISORDER. 2014 19 4578 31 N(6) -METHYLADENOSINE MODIFICATION IN CHRONIC STRESS RESPONSE DUE TO SOCIAL HIERARCHY POSITIONING OF MICE. APPROPRIATELY RESPONDING TO STRESSFUL EVENTS IS ESSENTIAL FOR MAINTAINING HEALTH AND WELL-BEING OF ANY ORGANISM. CONCERNING SOCIAL STRESS, THE RESPONSE IS NOT ALWAYS AS STRAIGHTFORWARD AS REACTING TO PHYSICAL STRESSORS, E.G., EXTREME HEAT, AND THUS HAS TO BE BALANCED SUBTLY. PARTICULARLY, REGULATORY MECHANISMS CONTRIBUTING TO GAINING RESILIENCE IN THE FACE OF MILD SOCIAL STRESS ARE NOT FULLY DECIPHERED YET. WE EMPLOYED AN INTRINSIC SOCIAL HIERARCHY STRESS PARADIGM IN MICE OF BOTH SEXES TO IDENTIFY CRITICAL FACTORS FOR POTENTIAL COPING STRATEGIES. WHILE GLOBAL TRANSCRIPTOMIC CHANGES COULD NOT BE OBSERVED IN MALE MICE, SEVERAL GENES PREVIOUSLY REPORTED TO BE INVOLVED IN SYNAPTIC PLASTICITY, LEARNING, AND ANXIETY-LIKE BEHAVIOR WERE DIFFERENTIALLY REGULATED IN FEMALE MICE. MOREOVER, CHANGES IN N(6)-METHYLADENOSINE (M(6)A)-MODIFICATION OF MRNA OCCURRED ASSOCIATED WITH CORTICOSTERONE LEVEL IN BOTH SEXES WITH, E.G., INCREASED GLOBAL AMOUNT IN SUBMISSIVE FEMALE MICE. IN ACCORDANCE WITH THIS, METTL14 AND WTAP, SUBUNITS OF THE METHYLTRANSFERASE COMPLEX, SHOWED ELEVATED LEVELS IN SUBMISSIVE FEMALE MICE. N(6)-ADENOSYL-METHYLATION IS THE MOST PROMINENT TYPE OF MRNA METHYLATION AND PLAYS A CRUCIAL ROLE IN PROCESSES SUCH AS METABOLISM, BUT ALSO RESPONSE TO PHYSICAL STRESS. OUR FINDINGS UNDERPIN ITS ESSENTIAL ROLE BY ALSO PROVIDING A LINK TO SOCIAL STRESS EVOKED BY HIERARCHY BUILDING WITHIN SAME-SEX GROUPS. AS RECENTLY, SEARCH FOR SMALL MOLECULE MODIFIERS FOR THE RESPECTIVE CLASS OF RNA MODIFYING ENZYMES HAS STARTED, THIS MIGHT EVEN LEAD TO NEW THERAPEUTIC APPROACHES AGAINST STRESS DISORDERS. 2021 20 5874 29 SWIMMING EXERCISE REVERSES CUMS-INDUCED CHANGES IN DEPRESSION-LIKE BEHAVIORS AND HIPPOCAMPAL PLASTICITY-RELATED PROTEINS. BACKGROUND: STRESS-INDUCED FAILED RESILIENCE OF BRAIN PLASTICITY CAN CONTRIBUTE TO THE ONSET AND RECURRENCE OF DEPRESSION. CHRONIC STRESS HAS BEEN REPORTED TO OPEN WINDOWS OF EPIGENETIC PLASTICITY IN HIPPOCAMPUS. HOWEVER, HOW HIPPOCAMPAL PLASTICITY UNDERLIES DEPRESSION-LIKE BEHAVIORS AND HOW IT ADAPTS IN RESPONSE TO STRESS HAS NOT BEEN ADDRESSED. THE PRESENT STUDY AIMED TO INVESTIGATE THE SIGNALING MECHANISMS OF CUMS AFFECTING HIPPOCAMPAL PLASTICITY-RELATED PROTEINS EXPRESSION AND THE REGULATION OF SWIMMING EXERCISE IN MICE. METHODS: MALE C57BL/6 MICE WERE SUBJECTED TO CHRONIC UNPREDICTABLE MILD STRESS (CUMS) FOR 7 WEEKS. FROM THE 4TH WEEK, CUMS MICE WERE TRAINED IN A MODERATE SWIMMING PROGRAM FOR A TOTAL OF 4 WEEKS. A VIDEOCOMPUTERIZED TRACKING SYSTEM WAS USED TO RECORD BEHAVIORS OF ANIMALS FOR A 5-MIN SESSION. REAL-TIME PCR AND WESTERN BLOTTING WERE USED TO EXAMINE GENE EXPRESSION IN MOUSE HIPPOCAMPUS. RESULTS: OUR RESULTS DEMONSTRATED THAT CUMS INDUCED DEPRESSION-LIKE BEHAVIORS, WHICH WERE REVERSED BY SWIMMING EXERCISE. MOREOVER, THE BEHAVIORAL CHANGES INDUCED BY CUMS AND EXERCISE WERE CORRELATED WITH HIPPOCAMPAL PLASTICITY-RELATED PROTEINS EXPRESSION OF GROWTH-ASSOCIATED PROTEIN-43 (GAP-43) AND SYNAPTOPHYSIN (SYN). THE MOLECULAR MECHANISMS REGULATING THIS PLASTICITY MAY INCLUDE SIRT1/MIRCORNA, CREB/BDNF, AND AKT/GSK-3BETA SIGNALING PATHWAYS. LIMITATIONS: WE DID NOT ESTABLISH A CORRELATION BETWEEN DEPRESSION-LIKE BEHAVIORS INDUCED BY CHRONIC STRESS AND EPIGENETIC CHANGES OF HIPPOCAMPAL PLASTICITY, EITHER A CAUSAL MOLECULAR SIGNALING UNDERLING THIS PLASTICITY. CONCLUSIONS: OUR FINDINGS HAVE IDENTIFIED SWIMMING EXERCISE EFFECTS ON CUMS-INDUCED CHANGES IN DEPRESSION-LIKE BEHAVIORS AND HIPPOCAMPAL PLASTICITY-RELATED PROTEINS, WHICH PROVIDE A FRAMEWORK FOR DEVELOPING NEW STRATEGIES TO TREAT STRESS-INDUCED DEPRESSION. 2018