1 1198 189 CORTICOSTERONE-MEDIATED REGULATION AND FUNCTIONS OF MIR-218-5P IN RAT BRAIN. CHRONIC STRESS IS ONE OF THE KEY PRECIPITATING FACTORS IN MAJOR DEPRESSIVE DISORDER (MDD). STRESS ASSOCIATED STUDIES HAVE UNDERSCORED THE MECHANISTIC ROLE OF EPIGENETIC MASTER PLAYERS LIKE MICRORNAS (MIRNAS) IN DEPRESSION PATHOPHYSIOLOGY AT BOTH PRECLINICAL AND CLINICAL LEVELS. PREVIOUSLY, WE HAD REPORTED CHANGES IN MIR-218-5P EXPRESSION IN RESPONSE TO CORTICOSTERONE (CORT) INDUCED CHRONIC STRESS. MIR-218-5P WAS ONE OF THE MOST SIGNIFICANTLY INDUCED MIRNAS IN THE PREFRONTAL CORTEX (PFC) OF RATS UNDER CHRONIC STRESS. IN THE PRESENT REPORT, WE HAVE INVESTIGATED HOW CHRONIC CORT EXPOSURE MECHANISTICALLY AFFECTED MIR-218-5P EXPRESSION IN THE RAT BRAIN AND HOW MIR-218 COULD TRIGGER MOLECULAR CHANGES ON ITS DOWNSTREAM REGULATORY PATHWAYS. ELEVATED EXPRESSION OF MIR-218-5P WAS FOUND IN THE PFC OF CORT-TREATED RATS. A GLUCOCORTICOID RECEPTOR (GR) TARGETED CHROMATIN-IMMUNOPRECIPITATION (CHIP) ASSAY REVEALED HIGH GR OCCUPANCY ON THE PROMOTER REGION OF SLIT3 GENE HOSTING MIR-218-2 IN ITS 3RD INTRON. RNA-SEQUENCING DATA BASED ON RNA INDUCED SILENCING COMPLEX IMMUNOPRECIPITATION (RISC-IP) WITH AGO2 IN SH-SY5Y CELLS DETECTED SIX CONSISTENT TARGET GENES OF MIR-218-5P (APOL4, DTWD1, BNIP1, METTL22, SNAPC1, AND HDAC6). THE EXPRESSION OF ALL FIVE GENES, EXCEPT APOL4, WAS SUCCESSFULLY VALIDATED WITH QPCR IN CORT-TREATED RAT PFC. FURTHER, HDAC6-BASED CHIP-SEQ EXPERIMENT HELPED IN MAPPING MAJOR GENOMIC LOCI ENRICHED FOR INTERGENIC REGIONS IN THE PFC OF CORT-TREATED RAT. A PROXIMITY-BASED GENE ONTOLOGY (GO) ANALYSIS REVEALED A MAJORITY OF THE INTERGENIC SITES TO BE PART OF KEY GENES IMPLICATED IN CENTRAL NERVOUS SYSTEM FUNCTIONS, NOTABLY SYNAPSE ORGANIZATION, NEURON PROJECTION MORPHOGENESIS, AND AXONOGENESIS. OUR RESULTS SUGGEST THAT THE UPREGULATION OF MIR-218-5P IN PFC OF CORT-TREATED RATS POSSIBLY RESULTED FROM GR BIDING IN THE PROMOTER REGION OF SLIT3 GENE. INTERESTINGLY, HDAC6 WAS ONE OF THE CONSISTENT TARGET GENES POTENTIALLY FOUND TO REGULATE CNS RELATED GENES BY CHROMATIN MODIFICATION. COLLECTIVELY, THESE FINDINGS ESTABLISH THE ROLE OF MIR-218-5P IN CHRONIC STRESS AND THE EPIGENETIC FUNCTION IT PLAYS TO INDUCE CHROMATIN-BASED TRANSCRIPTIONAL CHANGES OF SEVERAL CNS GENES IN TRIGGERING STRESS-INDUCED DISORDERS, INCLUDING DEPRESSION. THIS ALSO OPENS UP THE SCOPE TO UNDERSTAND THE ROLE OF MIR-218-5P AS A POTENTIAL TARGET FOR NONCODING RNA THERAPEUTICS IN CLINICAL DEPRESSION. 2022 2 3093 41 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 3 5467 47 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 4 2442 39 EPIGENETIC STABILITY IN THE ADULT MOUSE CORTEX UNDER CONDITIONS OF PHARMACOLOGICALLY INDUCED HISTONE ACETYLATION. HISTONE ACETYLATION IS CONSIDERED A MAJOR EPIGENETIC PROCESS THAT AFFECTS BRAIN DEVELOPMENT AND SYNAPTIC PLASTICITY, AS WELL AS LEARNING AND MEMORY. THE TRANSCRIPTIONAL EFFECTORS AND MORPHOLOGICAL CHANGES RESPONSIBLE FOR PLASTICITY AS A RESULT OF LONG-TERM MODIFICATIONS TO HISTONE ACETYLATION ARE NOT FULLY UNDERSTOOD. TO THIS END, WE PHARMACOLOGICALLY INHIBITED HISTONE DEACETYLATION USING TRICHOSTATIN A IN ADULT (6-MONTH-OLD) MICE AND FOUND SIGNIFICANT INCREASES IN THE LEVELS OF THE ACETYLATED HISTONE MARKS H3LYS9, H3LYS14 AND H4LYS12. HIGH-RESOLUTION TRANSCRIPTOME ANALYSIS OF DIVERSE BRAIN REGIONS UNCOVERED FEW DIFFERENCES IN GENE EXPRESSION BETWEEN TREATED AND CONTROL ANIMALS, NONE OF WHICH WERE PLASTICITY RELATED. INSTEAD, AFTER INCREASED HISTONE ACETYLATION, WE DETECTED A LARGE NUMBER OF NOVEL TRANSCRIPTIONALLY ACTIVE REGIONS, WHICH CORRESPOND TO LONG NON-CODING RNAS (LNCRNAS). WE ALSO SURPRISINGLY FOUND NO SIGNIFICANT CHANGES IN DENDRITIC SPINE PLASTICITY IN LAYERS 1 AND 2/3 OF THE VISUAL CORTEX USING LONG-TERM IN VIVO TWO-PHOTON IMAGING. OUR RESULTS INDICATE THAT CHRONIC PHARMACOLOGICALLY INDUCED HISTONE ACETYLATION CAN BE DECOUPLED FROM GENE EXPRESSION AND INSTEAD, MAY POTENTIALLY EXERT A POST-TRANSCRIPTIONAL EFFECT THROUGH THE DIFFERENTIAL PRODUCTION OF LNCRNAS. 2016 5 3141 51 GLOBAL GENE EXPRESSION AND CHROMATIN ACCESSIBILITY OF THE PERIPHERAL NERVOUS SYSTEM IN ANIMAL MODELS OF PERSISTENT PAIN. BACKGROUND: EFFORTS TO UNDERSTAND GENETIC VARIABILITY INVOLVED IN AN INDIVIDUAL'S SUSCEPTIBILITY TO CHRONIC PAIN SUPPORT A ROLE FOR UPSTREAM REGULATION BY EPIGENETIC MECHANISMS. METHODS: TO EXAMINE THE TRANSCRIPTOMIC AND EPIGENETIC BASIS OF CHRONIC PAIN THAT RESIDES IN THE PERIPHERAL NERVOUS SYSTEM, WE USED RNA-SEQ AND ATAC-SEQ OF THE RAT DORSAL ROOT GANGLION (DRG) TO IDENTIFY NOVEL MOLECULAR PATHWAYS ASSOCIATED WITH PAIN HYPERSENSITIVITY IN TWO WELL-STUDIED PERSISTENT PAIN MODELS INDUCED BY CHRONIC CONSTRICTION INJURY (CCI) OF THE SCIATIC NERVE AND INTRA-PLANTAR INJECTION OF COMPLETE FREUND'S ADJUVANT (CFA) IN RATS. RESULTS: OUR RNA-SEQ STUDIES IDENTIFY A VARIETY OF BIOLOGICAL PROCESS RELATED TO SYNAPSE ORGANIZATION, MEMBRANE POTENTIAL, TRANSMEMBRANE TRANSPORT, AND ION BINDING. INTERESTINGLY, GENES THAT ENCODE TRANSCRIPTIONAL REGULATORS WERE DISPROPORTIONATELY DOWNREGULATED IN BOTH MODELS. OUR ATAC-SEQ DATA PROVIDE A COMPREHENSIVE MAP OF CHROMATIN ACCESSIBILITY CHANGES IN THE DRG. A TOTAL OF 1123 REGIONS SHOWED CHANGES IN CHROMATIN ACCESSIBILITY IN ONE OR BOTH MODELS WHEN COMPARED TO THE NAIVE AND 31 SHARED DIFFERENTIALLY ACCESSIBLE REGIONS (DAR)S. FUNCTIONAL ANNOTATION OF THE DARS IDENTIFIED DISPARATE MOLECULAR FUNCTIONS ENRICHED FOR EACH PAIN MODEL WHICH SUGGESTS THAT CHROMATIN STRUCTURE MAY BE ALTERED DIFFERENTLY FOLLOWING SCIATIC NERVE INJURY AND HIND PAW INFLAMMATION. MOTIF ANALYSIS IDENTIFIED 17 DNA SEQUENCES KNOWN TO BIND TRANSCRIPTION FACTORS IN THE CCI DARS AND 33 IN THE CFA DARS. TWO MOTIFS WERE SIGNIFICANTLY ENRICHED IN BOTH MODELS. CONCLUSIONS: OUR IMPROVED UNDERSTANDING OF THE CHANGES IN CHROMATIN ACCESSIBILITY THAT OCCUR IN CHRONIC PAIN STATES MAY IDENTIFY REGULATORY GENOMIC ELEMENTS THAT PLAY ESSENTIAL ROLES IN MODULATING GENE EXPRESSION IN THE DRG. 2021 6 6804 53 [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 7 989 38 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 8 4405 44 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 9 4299 36 MICRORNA-15B CONTRIBUTES TO DEPRESSION-LIKE BEHAVIOR IN MICE BY AFFECTING SYNAPTIC PROTEIN LEVELS AND FUNCTION IN THE NUCLEUS ACCUMBENS. MAJOR DEPRESSION IS A PREVALENT AFFECTIVE DISORDER CHARACTERIZED BY RECURRENT LOW MOOD. IT PRESUMABLY RESULTS FROM STRESS-INDUCED DETERIORATIONS OF MOLECULAR NETWORKS AND SYNAPTIC FUNCTIONS IN BRAIN REWARD CIRCUITS OF GENETICALLY-SUSCEPTIBLE INDIVIDUALS THROUGH EPIGENETIC PROCESSES. EPIGENETIC REGULATOR MICRORNA-15B INHIBITS NEURONAL PROGENITOR PROLIFERATION AND IS UP-REGULATED IN THE MEDIAL PREFRONTAL CORTEX OF MICE THAT DEMONSTRATE DEPRESSION-LIKE BEHAVIOR, INDICATING THE CONTRIBUTION OF MICRORNA-15 TO MAJOR DEPRESSION. USING A MOUSE MODEL OF MAJOR DEPRESSION INDUCED BY CHRONIC UNPREDICTABLE MILD STRESS (CUMS), HERE WE EXAMINED THE EFFECTS OF MICRORNA-15B ON SYNAPSES AND SYNAPTIC PROTEINS IN THE NUCLEUS ACCUMBENS OF THESE MICE. THE APPLICATION OF A MICRORNA-15B ANTAGOMIR INTO THE NUCLEUS ACCUMBENS SIGNIFICANTLY REDUCED THE INCIDENCE OF CUMS-INDUCED DEPRESSION AND REVERSED THE ATTENUATIONS OF EXCITATORY SYNAPSE AND SYNTAXIN-BINDING PROTEIN 3 (STXBP3A)/VESICLE-ASSOCIATED PROTEIN 1 (VAMP1) EXPRESSION. IN CONTRAST, THE INJECTION OF A MICRORNA-15B ANALOG INTO THE NUCLEUS ACCUMBENS INDUCED DEPRESSION-LIKE BEHAVIOR AS WELL AS ATTENUATED EXCITATORY SYNAPSES AND STXBP3A/VAMP1 EXPRESSION SIMILAR TO THE DOWN-REGULATION OF THESE PROCESSES INDUCED BY THE CUMS. WE CONCLUDE THAT MICRORNA-15B-5P MAY PLAY A CRITICAL ROLE IN CHRONIC STRESS-INDUCED DEPRESSION BY DECREASING SYNAPTIC PROTEINS, INNERVATIONS, AND ACTIVITIES IN THE NUCLEUS ACCUMBENS. WE PROPOSE THAT THE TREATMENT OF ANTI-MICRORNA-15B-5P MAY CONVERT STRESS-INDUCED DEPRESSION INTO RESILIENCE. 2020 10 6895 33 [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 11 345 50 ALTERED BRAIN EXPRESSION OF DNA METHYLATION AND HYDROXYMETHYLATION EPIGENETIC ENZYMES IN A RAT MODEL OF NEUROPATHIC PAIN. THE ROLE OF EPIGENETICS IN CHRONIC PAIN AT THE SUPRASPINAL LEVEL IS YET TO BE FULLY CHARACTERIZED. DNA HISTONE METHYLATION IS CRUCIALLY REGULATED BY DE NOVO METHYLTRANSFERASES (DNMT1-3) AND TEN-ELEVEN TRANSLOCATION DIOXYGENASES (TET1-3). EVIDENCE HAS SHOWN THAT METHYLATION MARKERS ARE ALTERED IN DIFFERENT CNS REGIONS RELATED TO NOCICEPTION, NAMELY THE DORSAL ROOT GANGLIA, THE SPINAL CORD, AND DIFFERENT BRAIN AREAS. DECREASED GLOBAL METHYLATION WAS FOUND IN THE DRG, THE PREFRONTAL CORTEX, AND THE AMYGDALA, WHICH WAS ASSOCIATED WITH DECREASED DNMT1/3A EXPRESSION. IN CONTRAST, INCREASED METHYLATION LEVELS AND MRNA LEVELS OF TET1 AND TET3 WERE LINKED TO AUGMENTED PAIN HYPERSENSITIVITY AND ALLODYNIA IN INFLAMMATORY AND NEUROPATHIC PAIN MODELS. SINCE EPIGENETIC MECHANISMS MAY BE RESPONSIBLE FOR THE REGULATION AND COORDINATION OF VARIOUS TRANSCRIPTIONAL MODIFICATIONS DESCRIBED IN CHRONIC PAIN STATES, WITH THIS STUDY, WE AIMED TO EVALUATE THE FUNCTIONAL ROLE OF TET1-3 AND DNMT1/3A GENES IN NEUROPATHIC PAIN IN SEVERAL BRAIN AREAS. IN A SPARED NERVE INJURY RAT MODEL OF NEUROPATHIC PAIN, 21 DAYS AFTER SURGERY, WE FOUND INCREASED TET1 EXPRESSION IN THE MEDIAL PREFRONTAL CORTEX AND DECREASED EXPRESSION IN THE CAUDATE-PUTAMEN AND THE AMYGDALA; TET2 WAS UPREGULATED IN THE MEDIAL THALAMUS; TET3 MRNA LEVELS WERE REDUCED IN THE MEDIAL PREFRONTAL CORTEX AND THE CAUDATE-PUTAMEN; AND DNMT1 WAS DOWNREGULATED IN THE CAUDATE-PUTAMEN AND THE MEDIAL THALAMUS. NO STATISTICALLY SIGNIFICANT CHANGES IN EXPRESSION WERE OBSERVED WITH DNMT3A. OUR RESULTS SUGGEST A COMPLEX FUNCTIONAL ROLE FOR THESE GENES IN DIFFERENT BRAIN AREAS IN THE CONTEXT OF NEUROPATHIC PAIN. THE NOTION OF DNA METHYLATION AND HYDROXYMETHYLATION BEING CELL-TYPE SPECIFIC AND NOT TISSUE SPECIFIC, AS WELL AS THE POSSIBILITY OF CHRONOLOGICALLY DIFFERENTIAL GENE EXPRESSION AFTER THE ESTABLISHMENT OF NEUROPATHIC OR INFLAMMATORY PAIN MODELS, OUGHT TO BE ADDRESSED IN FUTURE STUDIES. 2023 12 2119 40 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 13 2297 37 EPIGENETIC REGULATION OF ACUTE INFLAMMATORY PAIN. ACUTE PAIN IS ASSOCIATED WITH TISSUE DAMAGE, WHICH RESULTS IN THE RELEASE OF INFLAMMATORY MEDIATORS. RECENT STUDIES POINT TO THE INVOLVEMENT OF EPIGENETIC MECHANISMS (DNA METHYLATION) IN THE DEVELOPMENT OF PAIN. WE HAVE FOUND THAT DURING ACUTE INFLAMMATORY PAIN INDUCED BY THE APPLICATION OF 10% MUSTARD OIL ON THE TONGUES OF RATS, LEVELS OF DNMT3A AND 3B WERE ELEVATED MARKEDLY (36 AND 42 % RESPECTIVELY), WHEREAS THE LEVEL OF DNMT1 WAS NOT CHANGED SIGNIFICANTLY. PREVIOUS INJECTION OF XEFOCAM WITH 0,4 MG/KG DOSE DECREASED LEVELS OF DNMT3A AND 3B (25 AND 24% RESPECTIVELY). THE LEVEL OF DNMT1 WAS NOT CHANGED SIGNIFICANTLY COMPARED TO THE CONTROL GROUP. THE FINDINGS SUPPORT THE IDEA THAT INHIBITORS OF DNA-METHYLTRANSFERASES COULD BE USEFUL FOR PAIN MANAGEMENT. OUR DATA SUGGEST THAT NSAIDS (ALONE OR IN COMBINATION WITH DNMT INHIBITORS) MAY BE PROPOSED AS POSSIBLE EPIGENETIC REGULATORY AGENTS, WHICH MAY PLAY A ROLE IN EPIGENETIC MECHANISMS INDIRECTLY THROUGH ALTERING THE ACTIVITY OF INFLAMMATORY MEDIATORS INVOLVED IN PAIN DEVELOPMENT. 2014 14 3370 54 HISTONE MODIFICATION OF NEDD4 UBIQUITIN LIGASE CONTROLS THE LOSS OF AMPA RECEPTORS AND COGNITIVE IMPAIRMENT INDUCED BY REPEATED STRESS. STRESS AND THE MAJOR STRESS HORMONE CORTICOSTERONE INDUCE PROFOUND INFLUENCES IN THE BRAIN. ALTERED HISTONE MODIFICATION AND TRANSCRIPTIONAL DYSFUNCTION HAVE BEEN IMPLICATED IN STRESS-RELATED MENTAL DISORDERS. WE PREVIOUSLY FOUND THAT REPEATED STRESS CAUSED AN IMPAIRMENT OF PREFRONTAL CORTEX (PFC)-MEDIATED COGNITIVE FUNCTIONS BY INCREASING THE UBIQUITINATION AND DEGRADATION OF AMPA-TYPE GLUTAMATE RECEPTORS VIA A MECHANISM DEPENDING ON THE E3 UBIQUITIN LIGASE NEDD4. HERE, WE DEMONSTRATED THAT IN PFC OF REPEATEDLY STRESSED RATS, ACTIVE GLUCOCORTICOID RECEPTOR HAD THE INCREASED BINDING TO THE GLUCOCORTICOID RESPONSE ELEMENT OF HISTONE DEACETYLASE 2 (HDAC2) PROMOTER, RESULTING IN THE UPREGULATION OF HDAC2. INHIBITION OR KNOCK-DOWN OF HDAC2 BLOCKED THE STRESS-INDUCED IMPAIRMENT OF SYNAPTIC TRANSMISSION, AMPAR EXPRESSION, AND RECOGNITION MEMORY. FURTHERMORE, WE FOUND THAT, IN STRESSED ANIMALS, THE HDAC2-DEPENDENT DOWNREGULATION OF HISTONE METHYLTRANSFERASE EHMT2 (G9A) LED TO THE LOSS OF REPRESSIVE HISTONE METHYLATION AT THE NEDD4-1 PROMOTER AND THE TRANSCRIPTIONAL ACTIVATION OF NEDD4. THESE RESULTS HAVE PROVIDED AN EPIGENETIC MECHANISM AND A POTENTIAL TREATMENT STRATEGY FOR THE DETRIMENTAL EFFECTS OF CHRONIC STRESS. SIGNIFICANCE STATEMENT: PROLONGED STRESS EXPOSURE CAN INDUCE ALTERED HISTONE MODIFICATION AND TRANSCRIPTIONAL DYSFUNCTION, WHICH MAY UNDERLIE THE PROFOUND INFLUENCE OF STRESS IN REGULATING BRAIN FUNCTIONS. WE REPORT AN IMPORTANT FINDING ABOUT THE EPIGENETIC MECHANISM CONTROLLING THE DETRIMENTAL EFFECTS OF REPEATED STRESS ON SYNAPTIC TRANSMISSION AND COGNITIVE FUNCTION. FIRST, IT HAS REVEALED THE STRESS-INDUCED ALTERATION OF KEY EPIGENETIC REGULATORS HDAC2 AND EHMT2, WHICH DETERMINES THE SYNAPTIC AND BEHAVIORAL EFFECTS OF REPEATED STRESS. SECOND, IT HAS UNCOVERED THE STRESS-INDUCED HISTONE MODIFICATION OF THE TARGET GENE NEDD4, AN E3 LIGASE THAT IS CRITICALLY INVOLVED IN THE UBIQUITINATION AND DEGRADATION OF AMPA RECEPTORS AND COGNITION. THIRD, IT HAS PROVIDED THE EPIGENETIC APPROACH, HDAC2 INHIBITION OR KNOCK-DOWN, TO RESCUE SYNAPTIC AND COGNITIVE FUNCTIONS IN STRESSED ANIMALS. 2016 15 226 40 ACUTE TRANSCRIPTOMIC AND EPIGENETIC ALTERATIONS AT T12 AFTER RAT T10 SPINAL CORD CONTUSIVE INJURY. SPINAL CORD INJURY IS A SEVERELY DEBILITATING CONDITION AFFECTING A SIGNIFICANT POPULATION IN THE USA. SPINAL CORD INJURY PATIENTS OFTEN HAVE INCREASED RISK OF DEVELOPING PERSISTENT NEUROPATHIC PAIN AND OTHER NEURODEGENERATIVE CONDITIONS BEYOND THE PRIMARY LESION CENTER LATER IN THEIR LIFE. THE MOLECULAR MECHANISM CONFERRING TO THE "LATENT" DAMAGES AT DISTAL TISSUES, HOWEVER, REMAINS ELUSIVE. HERE, WE STUDIED MOLECULAR CHANGES CONFERRING ABNORMAL FUNCTIONALITY AT DISTAL SPINAL CORD (T12) BEYOND THE LESION CENTER (T10) BY COMBINING NEXT-GENERATION SEQUENCING (RNA- AND BISULFITE SEQUENCING), SUPER-RESOLUTION MICROSCOPY, AND IMMUNOFLUORESCENCE STAINING AT 7 DAYS POST INJURY. WE OBSERVED SIGNIFICANT TRANSCRIPTOMIC CHANGES PRIMARILY ENRICHED IN NEUROINFLAMMATION AND SYNAPTOGENESIS ASSOCIATED PATHWAYS. TRANSCRIPTION FACTORS (TFS) THAT REGULATE NEUROGENESIS AND NEURON PLASTICITY, INCLUDING EGR1, KLF4, AND MYC, ARE SIGNIFICANTLY UPREGULATED. ALONG WITH GLOBAL CHANGES IN CHROMATIN ARRANGEMENTS AND DNA METHYLATION, INCLUDING 5-METHYLCYTOSINE (5MC) AND 5-HYDROXYMETHYLCYTOSINE (5HMC), BISULFITE SEQUENCING FURTHER REVEALS THE INVOLVEMENT OF DNA METHYLATION CHANGES IN REGULATING CYTOKINE, GROWTH FACTOR, AND ION CHANNEL EXPRESSION. COLLECTIVELY, OUR RESULTS PAVE THE WAY TOWARDS UNDERSTANDING TRANSCRIPTOMIC AND EPIGENOMIC MECHANISM IN CONFERRING LONG-TERM DISEASE RISKS AT DISTAL TISSUES AWAY FROM THE PRIMARY LESION CENTER AND SHED LIGHT ON POTENTIAL MOLECULAR TARGETS THAT GOVERN THE REGULATORY MECHANISM AT DISTAL SPINAL CORD TISSUES. 2023 16 6794 43 [EFFECT OF BENZO(A)PYRENE ON THE EXPRESSION OF AHR-REGULATED MICRORNA IN FEMALE AND MALE RAT LUNGS]. SMOKING IS THE MAIN RISK FACTOR FOR LUNG CANCER, MAINLY DUE TO PRESENCE OF NITROSAMINES AND POLYCYCLIC AROMATIC HYDROCARBONS, INCLUDING BENZO[A]PYRENE (BP) IN TOBACCO SMOKE COMPOSITION. THE GENOTOXIC EFFECT OF BP IS BASED ON THE HIGH DNA-BINDING ABILITY OF ITS METABOLITES, WHILE THE EPIGENETIC EFFECTS ARE MEDIATED BY A CHANGE IN THE EXPRESSION OF CANCER RELATED GENES OR REGULATORY RNAS. IT HAS BEEN SHOWN THAT WOMEN HAVE A HIGHER RISK TO DEVELOP LUNG CANCER UPON SMOKING RATHER THAN MEN. WE HYPOTHESIZED THAT CROSSTALK BETWEEN SIGNALING PATHWAYS ACTIVATED BY BP AND ESTROGENS COULD UNDERLIE THE SEX-DEPENDENT DIFFERENCES IN MIRNAS EXPRESSION. TO TEST THIS HYPOTHESIS, MALE AND FEMALE RATS WERE SUBJECTED TO SHORT-TERM OR LONG-TERM BP EXPOSURE. USING IN SILICO ANALYSIS, MIRNAS CONTAINING THE ER- AND AHR-BINDING SITES IN THE PROMOTERS OF THE GENES (OR HOST GENES) WERE SELECTED. DURING CHRONIC EXPOSURE OF BP THE EXPRESSION OF MIR-22-3P, -29A-3P, -126A-3P, -193B-5P IN THE LUNGS OF MALE RATS WERE SIGNIFICANTLY INCREASED, WHILE THE LEVEL OF MIRNA-483-3P WERE DECREASED. EXPRESSION OF MIRNA-483-3P WAS UP-REGULATED DURING CHRONIC BP EXPOSURE IN THE LUNGS OF FEMALE RATS AND THE LEVELS OF OTHER STUDIED MIRNAS WERE UNCHANGED. IN TURN, CHANGES IN THE EXPRESSION OF MIRNAS WERE FOLLOWED BY CHANGES IN THE EXPRESSION OF THEIR TARGET GENES, INCLUDING PTEN, EMP2, IGF1, ITGA6, SLC34A2, AND THE OBSERVED CHANGES IN FEMALE AND MALE RAT LUNGS WERE VARIED. THUS, OUR RESULTS SUGGEST THAT SEX-DEPENDENT EPIGENETIC EFFECTS OF BP MAY BE BASED ON DIFFERENT EXPRESSION OF AHR- AND ER- REGULATED MIRNAS. 2020 17 5579 49 ROLE OF MORPHINE, MIR-212/132 AND MU OPIOID RECEPTOR IN THE REGULATION OF BDNF IN ZEBRAFISH EMBRYOS. BACKGROUND: MORPHINE IS ONE OF THE FIRST-LINE THERAPIES FOR THE TREATMENT OF PAIN DESPITE ITS SECONDARY EFFECTS. IT MODIFIES THE EXPRESSION OF EPIGENETIC FACTORS LIKE MIRNAS. IN THE PRESENT STUDY, WE ANALYZED MIR-212 AND MIR-132 AND THEIR IMPLICATION IN MORPHINE EFFECTS IN THE ZEBRAFISH CENTRAL NERVOUS SYSTEM (CNS) THROUGH THE REGULATION OF BDNF EXPRESSION. METHODS: WE USED CONTROL AND KNOCK-DOWN ZEBRAFISH EMBRYOS TO ASSESS THE EFFECTS OF MORPHINE IN MIRNAS 212/132 AND MITOTIC OR APOPTOTIC CELLS BY QPCR, IMMUNOHISTOCHEMISTRY AND TUNEL ASSAY, RESPECTIVELY. BDNF AND TRKB WERE STUDIED BY WESTERN BLOT AND THROUGH A PRIMARY NEURON CULTURE. A LUCIFERASE ASSAY WAS PERFORMED TO CONFIRM THE BINDING OF MIRNAS 212/132 TO MECP2. RESULTS: MORPHINE EXPOSURE DECREASES MIR-212 BUT UPREGULATES MIR-132, AS WELLS AS BDNF AND TRKB, AND CHANGES THE LOCALIZATION OF PROLIFERATIVE CELLS. HOWEVER, BDNF EXPRESSION WAS DOWNREGULATED WHEN MIRNAS 212/132 AND OPRM1 WERE KNOCKED-DOWN. FURTHERMORE, WE PROVED THAT THESE MIRNAS INHIBIT MECP2 EXPRESSION BY BINDING TO ITS MRNA SEQUENCE. THE DESCRIBED EFFECTS WERE CORROBORATED IN A PRIMARY NEURON CULTURE FROM ZEBRAFISH EMBRYOS. CONCLUSIONS: WE PROPOSE A MECHANISM IN WHICH MORPHINE ALTERS THE LEVELS OF MIRNAS 212/132 INCREASING BDNF EXPRESSION THROUGH MECP2 INHIBITION. OPRM1 IS ALSO DIRECTLY INVOLVED IN THIS REGULATION. THE PRESENT WORK CONFIRMS A RELATIONSHIP BETWEEN THE OPIOID SYSTEM AND NEUROTROPHINS AND SHOWS A KEY ROLE OF MIR-212 AND MIR-132 ON MORPHINE EFFECTS THROUGH THE REGULATION OF BDNF PATHWAY. GENERAL SIGNIFICANCE: MIRNAS 212/132 ARE NOVEL REGULATORS OF MORPHINE EFFECTS ON CNS. OPRM1 CONTROLS THE NORMAL EXPRESSION OF BDNF. 2016 18 5007 41 PERIPHERAL NERVE INJURY IS ASSOCIATED WITH CHRONIC, REVERSIBLE CHANGES IN GLOBAL DNA METHYLATION IN THE MOUSE PREFRONTAL CORTEX. CHANGES IN BRAIN STRUCTURE AND CORTICAL FUNCTION ARE ASSOCIATED WITH MANY CHRONIC PAIN CONDITIONS INCLUDING LOW BACK PAIN AND FIBROMYALGIA. THE MAGNITUDE OF THESE CHANGES CORRELATES WITH THE DURATION AND/OR THE INTENSITY OF CHRONIC PAIN. MOST STUDIES REPORT CHANGES IN COMMON AREAS INVOLVED IN PAIN MODULATION, INCLUDING THE PREFRONTAL CORTEX (PFC), AND PAIN-RELATED PATHOLOGICAL CHANGES IN THE PFC CAN BE REVERSED WITH EFFECTIVE TREATMENT. WHILE THE MECHANISMS UNDERLYING THESE CHANGES ARE UNKNOWN, THEY MUST BE DYNAMICALLY REGULATED. EPIGENETIC MODULATION OF GENE EXPRESSION IN RESPONSE TO EXPERIENCE AND ENVIRONMENT IS REVERSIBLE AND DYNAMIC. EPIGENETIC MODULATION BY DNA METHYLATION IS ASSOCIATED WITH ABNORMAL BEHAVIOR AND PATHOLOGICAL GENE EXPRESSION IN THE CENTRAL NERVOUS SYSTEM. DNA METHYLATION MIGHT ALSO BE INVOLVED IN MEDIATING THE PATHOLOGIES ASSOCIATED WITH CHRONIC PAIN IN THE BRAIN. WE THEREFORE TESTED A) WHETHER ALTERATIONS IN DNA METHYLATION ARE FOUND IN THE BRAIN LONG AFTER CHRONIC NEUROPATHIC PAIN IS INDUCED IN THE PERIPHERY USING THE SPARED NERVE INJURY MODAL AND B) WHETHER THESE INJURY-ASSOCIATED CHANGES ARE REVERSIBLE BY INTERVENTIONS THAT REVERSE THE PATHOLOGIES ASSOCIATED WITH CHRONIC PAIN. SIX MONTHS FOLLOWING PERIPHERAL NERVE INJURY, ABNORMAL SENSORY THRESHOLDS AND INCREASED ANXIETY WERE ACCOMPANIED BY DECREASED GLOBAL METHYLATION IN THE PFC AND THE AMYGDALA BUT NOT IN THE VISUAL CORTEX OR THE THALAMUS. ENVIRONMENTAL ENRICHMENT ATTENUATED NERVE INJURY-INDUCED HYPERSENSITIVITY AND REVERSED THE CHANGES IN GLOBAL PFC METHYLATION. FURTHERMORE, GLOBAL PFC METHYLATION CORRELATED WITH MECHANICAL AND THERMAL SENSITIVITY IN NEUROPATHIC MICE. IN SUMMARY, INDUCTION OF CHRONIC PAIN BY PERIPHERAL NERVE INJURY IS ASSOCIATED WITH EPIGENETIC CHANGES IN THE BRAIN. THESE CHANGES ARE DETECTED LONG AFTER THE ORIGINAL INJURY, AT A LONG DISTANCE FROM THE SITE OF INJURY AND ARE REVERSIBLE WITH ENVIRONMENTAL MANIPULATION. CHANGES IN BRAIN STRUCTURE AND CORTICAL FUNCTION THAT ARE ASSOCIATED WITH CHRONIC PAIN CONDITIONS MAY THEREFORE BE MEDIATED BY EPIGENETIC MECHANISMS. 2013 19 3076 36 GENOME-WIDE EPIGENOMIC ANALYSES IN PATIENTS WITH NOCICEPTIVE AND NEUROPATHIC CHRONIC PAIN SUBTYPES REVEALS ALTERATIONS IN METHYLATION OF GENES INVOLVED IN THE NEURO-MUSCULOSKELETAL SYSTEM. NOCICEPTIVE PAIN INVOLVES THE ACTIVATION OF NOCICEPTORS WITHOUT DAMAGE TO THE NERVOUS SYSTEM, WHEREAS NEUROPATHIC PAIN IS RELATED TO AN ALTERATION IN THE CENTRAL OR PERIPHERAL NERVOUS SYSTEM. CHRONIC PAIN ITSELF AND THE TRANSITION FROM ACUTE TO CHRONIC PAIN MAY BE EPIGENETICALLY CONTROLLED. IN THIS CROSS-SECTIONAL STUDY, A GENOME-WIDE DNA METHYLATION ANALYSIS WAS PERFORMED USING THE BLOOD DNA REDUCED REPRESENTATION BISULFITE SEQUENCING (RRBS) TECHNIQUE. THREE PROSPECTIVE COHORTS INCLUDING 20 HEALTHY CONTROLS (CTL), 18 PATIENTS WITH CHRONIC NOCICEPTIVE PAIN (NOCI), AND 19 PATIENTS WITH CHRONIC NEUROPATHIC PAIN (NEURO) WERE COMPARED AT BOTH THE SINGLE CPG AND DIFFERENTIALLY METHYLATED REGION (DMR) LEVELS. GENES WITH DMRS WERE SEEN IN THE NOCI AND NEURO GROUPS BELONGED TO THE NEURO-MUSCULOSKELETAL SYSTEM AND DIFFERED BETWEEN NOCI AND NEURO PATIENTS. OUR RESULTS DEMONSTRATE THAT THE EPIGENETIC DISTURBANCES ACCOMPANYING NOCICEPTIVE PAIN ARE VERY DIFFERENT FROM THOSE ACCOMPANYING NEUROPATHIC PAIN. IN THE FORMER, AMONG OTHERS, THE EPIGENETIC DISTURBANCE OBSERVED WOULD AFFECT THE FUNCTION OF THE OPIOID ANALGESIC SYSTEM, WHEREAS IN THE LATTER IT WOULD AFFECT THAT OF THE GABAERGIC REWARD SYSTEM. THIS STUDY PRESENTS BIOLOGICAL FINDINGS THAT HELP TO CHARACTERIZE NOCI- AND NEURO-AFFECTED PATHWAYS AND OPENS THE POSSIBILITY OF DEVELOPING EPIGENETIC DIAGNOSTIC ASSAYS. PERSPECTIVE: OUR RESULTS HELP TO EXPLAIN THE VARIOUS BIOLOGICAL PATHWAYS MODIFICATIONS UNDERLYING THE DIFFERENT CLINICAL MANIFESTATIONS OF NOCICEPTIVE AND NEUROPATHIC PAINS. FURTHERMORE, THE NEW TARGETS IDENTIFIED IN OUR STUDY MIGHT HELP TO DISCOVER MORE SPECIFIC TREATMENTS FOR NOCICEPTIVE OR NEUROPATHIC PAINS. 2022 20 6419 45 THE TET2-UPF1 COMPLEX MODULATES MRNA STABILITY UNDER STRESS CONDITIONS. INTRODUCTION: ENVIRONMENTAL STRESS PROMOTES EPIGENETIC ALTERATIONS THAT IMPACT GENE EXPRESSION AND SUBSEQUENTLY PARTICIPATE IN THE PATHOLOGICAL PROCESSES OF THE DISORDER. AMONG EPIGENETIC REGULATIONS, TEN-ELEVEN TRANSLOCATION (TET) ENZYMES OXIDIZE 5-METHYLCYTOSINE (5MC) TO 5-HYDROXYMETHYLCYTOSINE (5HMC) IN DNA AND RNA AND FUNCTION AS CRITICAL PLAYERS IN THE PATHOGENESIS OF DISEASES. OUR PREVIOUS RESULTS SHOWED THAT CHRONIC STRESS INCREASES THE EXPRESSION OF CYTOPLASMIC TET2 IN THE HIPPOCAMPUS OF MICE EXPOSED TO CHRONIC MILD STRESS (CMS). WHETHER THE CYTOPLASMIC TET2 ALTERS RNA 5HMC MODIFICATION IN CHRONIC STRESS-RELATED PROCESSES REMAINS LARGELY UNKNOWN. METHODS: TO EXPLORE THE ROLE OF CYTOPLASMIC TET2 UNDER CMS CONDITIONS, WE ESTABLISHED CMS MICE MODEL AND DETECTED THE EXPRESSION OF RNA 5HMC BY DOT BLOT. WE VERIFIED THE INTERACTION OF TET2 AND ITS INTERACTING PROTEIN BY CO-IMMUNOPRECIPITATION COMBINED WITH MASS SPECTROMETRY AND SCREENED DOWNSTREAM TARGET GENES BY CLUSTER ANALYSIS OF TET2 AND UPSTREAM FRAMESHIFT 1 (UPF1) INTERACTING RNA. THE EXPRESSION OF PROTEIN WAS DETECTED BY WESTERN BLOT AND THE EXPRESSION OF THE SCREENED TARGET GENES WAS DETECTED BY QRT-PCR. RESULTS: IN THIS STUDY, WE FOUND THAT INCREASED CYTOPLASMIC TET2 EXPRESSION UNDER CMS CONDITIONS LEADS TO INCREASE IN TOTAL RNA 5HMC MODIFICATION. TET2 INTERACTED WITH THE KEY NON-SENSE-MEDIATED MRNA DECAY (NMD) FACTOR UPF1, REGULATED THE STABILITY OF STRESS-RELATED GENES SUCH AS UNC5B MRNA, AND MIGHT THEREBY AFFECT NEURODEVELOPMENT. DISCUSSION: IN SUMMARY, THIS STUDY REVEALED THAT TET2-MEDIATED RNA 5HMC MODIFICATION IS INVOLVED IN STRESS-RELATED MRNA STABILITY REGULATION AND MAY SERVE AS A POTENTIAL THERAPEUTIC TARGET FOR CHRONIC STRESS-RELATED DISEASES SUCH AS DEPRESSION. 2023