1 510 122 ASSOCIATION OF RASGRF1 METHYLATION WITH EPILEPTIC SEIZURES. DNA METHYLATION, ONE OF THE MECHANISMS OF EPIGENETIC REGULATION, HAS BEEN SUGGESTED TO BE RELATED WITH EPILEPSY. RASGRF1 IS A PATERNALLY IMPRINTED GENE AND HAS A DIFFERENTIALLY METHYLATED REGION (DMR) AT THE PROMOTER THAT CAN SILENCE GENE EXPRESSION. WE HAVE PREVIOUSLY OBSERVED THE DOWN-REGULATION OF RASGRF1 IN THE TEMPORAL NEOCORTEX OF EPILEPSY PATIENTS AND IN THE HIPPOCAMPUS OF EPILEPTIC ANIMALS. HERE, WE FURTHER EXPLORED THE DYNAMIC CHANGE (1-DAY ACUTE PERIOD, 10-DAY LATENT PERIOD AND 45-DAY CHRONIC PHASE) OF DNA METHYLATION AND RASGRF1 EXPRESSION AFTER ACUTE EPILEPTIC SEIZURES IN KAINIC ACID (KA)-TREATED MICE, AND WE OBSERVED THE IMPACT OF N-PHTHALYL-L-TRYPTOPHAN (RG108), A DNA METHYLTRANSFERASE (DNMT) INHIBITOR, ON AN ACUTE EPILEPTIC MODEL BY POLYMERASE CHAIN REACTION (PCR), WESTERN BLOTTING, AND BISULFITE SEQUENCING PCR (BSP). THE RESULTS DIRECTLY SHOWED THAT THE METHYLATION OF THE RASGRF1 PROMOTER GRADUALLY INCREASED AND REACHED A MAXIMAL LEVEL AT THE LATENT PERIOD, WITH SUBSEQUENT SUPPRESSION OF RASGRF1 MRNA AND PROTEIN EXPRESSION LEVELS, WHICH REACHED A MINIMUM LEVEL IN THE CHRONIC PHASE. RG108 INHIBITED THE INCREASED METHYLATION OF THE RASGRF1 GENE, WITH SIGNIFICANT INHIBITION OCCURRING AT THE LATENT PERIOD, AND RESTORED RASGRF1 EXPRESSION LEVELS IN THE CHRONIC PHASE. IN ADDITION, WE DEMONSTRATED THAT RG108 COULD SUPPRESS ACUTE EPILEPTIC SEIZURES IN KA-TREATED MICE AND EPILEPTIC DISCHARGES IN 4-AMINOPYRIDINE (4-AP)-TREATED HIPPOCAMPAL SLICES. THESE FINDINGS DEMONSTRATE THAT RASGRF1 IS CLOSELY ASSOCIATED WITH EPILEPSY VIA THE ABERRANT METHYLATION OF RASGRF1, AND REGULATING THE METHYLATION STATUS OF RELEVANT GENES MIGHT BE AN INTRIGUING TOPIC IN FUTURE RESEARCH ON EPILEPSY. 2017 2 5348 64 RASGRF1, A POTENTIAL METHYLATIC MEDIATOR OF ANTI-EPILEPTOGENESIS? EPILEPTOGENESIS, INDUCED BY STATUS EPILEPTICUS (SE), IS A CHRONIC PROCESS, AND INTERVENTION IN THIS PROGRESS MAY PREVENT CHRONIC EPILEPSY. IT HAS BEEN PROPOSED THAT DNA METHYLATION MIGHT BE RELATED WITH EPILEPTOGENESIS. RASGRF1 HAS A DIFFERENTIALLY METHYLATED REGION AT THE PROMOTER WHICH CAN SILENCE GENE EXPRESSION. WE HAVE PREVIOUSLY OBSERVED THE DOWN-REGULATION OF RASGRF1 IN EPILEPSY PATIENTS AND PROVED THAT HYPERMETHYLATION OF RASGRF1 REACHES MAXIMAL LEVEL AT THE LATENT PERIOD IN MICE AFTER KAINATE-INDUCED SE (KA MICE), WITH CORRESPONDING ALTERATION OF RASGRF1 EXPRESSION. IN THE PRESENT STUDY, N-PHTHALYL-L-TRYPTOPHAN (RG108), A DNA METHYLTRANSFERASE INHIBITOR, WAS APPLIED IN KA MICE AT LATENT PHASE AND THE BEHAVIOR, ELECTROENCEPHALOGRAM AND PATHOLOGICAL CHANGES WERE OBSERVED IN CHRONIC PHASE. METHYLATION AND EXPRESSION OF RASGRF1 WERE DETERMINED BY POLYMERASE CHAIN REACTION (PCR), WESTERN BLOTTING, AND BISULFITE SEQUENCING PCR. THE RESULTS SHOWED THAT THE INCIDENCE OF SPONTANEOUS RECURRENT SEIZURES (SRS) WAS SIGNIFICANTLY LOWER IN THE RG108 GROUP THAN THE NORMAL SALINE (NS) GROUP. SUBGROUP ANALYSIS SHOWED SIGNIFICANT HYPERMETHYLATION AND LOWER EXPRESSION OF RASGRF1 IN THE RG108-SRS SUBGROUP AND THE NS-SRS SUBGROUP BUT NOT IN THE RG108-NSRS (NO SRS) SUBGROUP AND THE NS-NSRS SUBGROUP COMPARED WITH THE CONTROL GROUP. NO SIGNIFICANT DIFFERENCE WAS FOUND BETWEEN THE RG108-SRS AND NS-SRS SUBGROUPS. MEANWHILE, HIPPOCAMPAL NEURONAL LOSS WAS OBSERVED IN RG108-SRS AND NS-SRS SUBGROUPS. WE THUS DEMONSTRATED THAT RG108 COULD MODIFY THE PROGRESSION OF EPILEPTOGENESIS AFTER KA INDUCED SE AND PREVENT CHRONIC EPILEPSY. MEANWHILE, HYPERMETHYLATION OF RASGRF1 AFTER KA INDUCED SE COULD BE REVERSED WITH CORRESPONDING CHANGES OF RASGRF1 EXPRESSION. ADDITIONALLY, WE SPECULATED THAT RASGRF1 MIGHT BE A POTENTIAL EPIGENETIC MEDIATOR IN EPILEPTOGENESIS AND CHRONIC EPILEPSY. 2018 3 5345 47 RAPID CHANGES IN EXPRESSION OF CLASS I AND IV HISTONE DEACETYLASES DURING EPILEPTOGENESIS IN MOUSE MODELS OF TEMPORAL LOBE EPILEPSY. A PROMINENT ROLE OF EPIGENETIC MECHANISMS IN MANIFESTATION OF EPILEPSY HAS BEEN PROPOSED. THUS ALTERED HISTONE H3 AND H4 ACETYLATION HAS BEEN DEMONSTRATED IN EXPERIMENTAL MODELS OF TEMPORAL LOBE EPILEPSY (TLE). WE NOW INVESTIGATED CHANGES IN THE EXPRESSION OF THE CLASS I AND CLASS IV HISTONE DEACETYLASES (HDAC) IN TWO COMPLEMENTARY MOUSE TLE MODELS. UNILATERAL INTRAHIPPOCAMPAL INJECTION OF KAINIC ACID (KA) INDUCED A STATUS EPILEPTICUS LASTING 6 TO 24H, DEVELOPMENT OF SPONTANEOUS LIMBIC SEIZURES (2 TO 3 DAYS AFTER KA INJECTION) AND CHRONIC EPILEPSY, AS REVEALED BY TELEMETRIC RECORDINGS OF THE EEGS. MICE WERE KILLED AT DIFFERENT INTERVALS AFTER KA INJECTION AND EXPRESSION OF HDAC MRNAS WAS INVESTIGATED BY IN SITU HYBRIDIZATION. WE OBSERVED MARKED DECREASES IN THE EXPRESSION OF HDACS 1, 2 AND 11 (BY UP TO 75%) IN THE GRANULE CELL AND PYRAMIDAL CELL LAYERS OF THE HIPPOCAMPUS DURING THE ACUTE STATUS EPILEPTICUS (2 TO 6H AFTER KA INJECTION). THIS WAS FOLLOWED BY INCREASED EXPRESSION OF ALL CLASS I HDAC MRNAS IN ALL PRINCIPAL CELL LAYERS OF THE HIPPOCAMPUS AFTER 12 TO 48 H. IN THE CHRONIC PHASE, 14 AND 28 DAYS AFTER KA, ONLY MODEST INCREASES IN THE EXPRESSION OF HDAC1 MRNA WERE OBSERVED IN GRANULE AND PYRAMIDAL CELLS. IMMUNOHISTOCHEMISTRY USING AN ANTIBODY DETECTING HDAC2 REVEALED RESULTS CONSISTENT WITH THE MRNA DATA AND INDICATES ALSO EXPRESSION IN GLIAL CELLS ON THE INJECTION SIDE. SIMILAR CHANGES AS SEEN IN THE KA MODEL WERE OBSERVED AFTER A PILOCARPINE-INDUCED STATUS EPILEPTICUS EXCEPT THAT DECREASES IN HDACS 2, 3 AND 8 WERE ALSO SEEN AT THE CHRONIC 28 DAY INTERVAL. THE PROMINENT DECREASES IN HDAC EXPRESSION DURING STATUS EPILEPTICUS ARE CONSISTENT WITH THE PREVIOUSLY DEMONSTRATED INCREASED EXPRESSION OF NUMEROUS PROTEINS AND WITH THE AUGMENTED ACETYLATION OF HISTONE H4. IT IS SUGGESTED THAT RESPECTIVE PUTATIVE GENE PRODUCTS COULD FACILITATE PROCONVULSIVE AS WELL AS ANTICONVULSIVE MECHANISMS. THE INCREASED EXPRESSION OF ALL CLASS I HDACS DURING THE "SILENT PHASE", ON THE OTHER HAND, MAY BE RELATED TO DECREASED HISTONE ACETYLATION, WHICH COULD CAUSE A DECREASE IN EXPRESSION OF CERTAIN PROTEINS, A MECHANISM THAT COULD ALSO PROMOTE EPILEPTOGENESIS. THUS, ADDRESSING HDAC EXPRESSION MAY HAVE A THERAPEUTIC POTENTIAL IN INTERFERING WITH A STATUS EPILEPTICUS AND WITH THE MANIFESTATION OF TLE. 2015 4 5617 42 SARCOSINE SUPPRESSES EPILEPTOGENESIS IN RATS WITH EFFECTS ON HIPPOCAMPAL DNA METHYLATION. EPILEPTOGENESIS IS A COMMON CONSEQUENCE OF BRAIN INSULTS, HOWEVER, THE PREVENTION OR DELAY OF THE EPILEPTOGENIC PROCESS REMAINS AN IMPORTANT UNMET MEDICAL CHALLENGE. OVEREXPRESSION OF GLYCINE TRANSPORTER 1 (GLYT1) IS PROPOSED AS A PATHOLOGICAL HALLMARK IN THE HIPPOCAMPUS OF PATIENTS WITH TEMPORAL LOBE EPILEPSY (TLE), AND WE PREVIOUSLY DEMONSTRATED IN RODENT EPILEPSY MODELS THAT AUGMENTATION OF GLYCINE SUPPRESSED CHRONIC SEIZURES AND ALTERED ACUTE SEIZURE THRESHOLDS. IN THE PRESENT STUDY WE EVALUATED THE EFFECT OF THE GLYT1 INHIBITOR, SARCOSINE (AKA N-METHYLGLYCINE), ON EPILEPTOGENESIS AND ALSO INVESTIGATED POSSIBLE MECHANISMS. WE DEVELOPED A MODIFIED RAPID KINDLING MODEL OF EPILEPTOGENESIS IN RATS COMBINED WITH SEIZURE SCORE MONITORING TO EVALUATE THE ANTIEPILEPTOGENIC EFFECT OF SARCOSINE. WE USED IMMUNOHISTOCHEMISTRY AND WESTERN BLOT ANALYSIS FOR THE EVALUATION OF GLYT1 EXPRESSION AND EPIGENETIC CHANGES OF 5-METHYLCYTOSINE (5MC) AND 5-HYDROXYMETHYLCYTOSINE (5HMC) IN THE EPILEPTOGENIC HIPPOCAMPI OF RATS, AND FURTHER EVALUATED EXPRESSION CHANGES IN ENZYMES INVOLVED IN THE REGULATION OF DNA METHYLATION, TEN-ELEVEN TRANSLOCATION METHYLCYTOSINE DIOXYGENASE 1 (TET1), DNA-METHYLTRANSFERASE 1 (DNMT1), AND DNMT3A. OUR RESULTS DEMONSTRATED: (I) EXPERIMENTAL EVIDENCE THAT SARCOSINE (3 G/KG, I.P. DAILY) SUPPRESSED KINDLING EPILEPTOGENESIS IN RATS; (II) THE SARCOSINE-INDUCED ANTIEPILEPTOGENIC EFFECT WAS ACCOMPANIED BY A SUPPRESSED HIPPOCAMPAL GLYT1 EXPRESSION AS WELL AS A REDUCTION OF HIPPOCAMPAL 5MC LEVELS AND A CORRESPONDING INCREASE IN 5HMC; AND (III) SARCOSINE TREATMENT CAUSED DIFFERENTIAL EXPRESSION CHANGES OF TET1 AND DNMTS. TOGETHER, THESE FINDINGS SUGGEST THAT SARCOSINE HAS UNPRECEDENTED DISEASE-MODIFYING PROPERTIES IN A KINDLING MODEL OF EPILEPTOGENESIS IN RATS, WHICH WAS ASSOCIATED WITH ALTERED HIPPOCAMPAL DNA METHYLATION. THUS, MANIPULATION OF THE GLYCINE SYSTEM IS A POTENTIAL THERAPEUTIC APPROACH TO ATTENUATE THE DEVELOPMENT OF EPILEPSY. 2020 5 1425 31 DIFFERENTIAL DNA METHYLATION PROFILES OF CODING AND NON-CODING GENES DEFINE HIPPOCAMPAL SCLEROSIS IN HUMAN TEMPORAL LOBE EPILEPSY. TEMPORAL LOBE EPILEPSY IS ASSOCIATED WITH LARGE-SCALE, WIDE-RANGING CHANGES IN GENE EXPRESSION IN THE HIPPOCAMPUS. EPIGENETIC CHANGES TO DNA ARE ATTRACTIVE MECHANISMS TO EXPLAIN THE SUSTAINED HYPEREXCITABILITY OF CHRONIC EPILEPSY. HERE, THROUGH METHYLATION ANALYSIS OF ALL ANNOTATED C-PHOSPHATE-G ISLANDS AND PROMOTER REGIONS IN THE HUMAN GENOME, WE REPORT A PILOT STUDY OF THE METHYLATION PROFILES OF TEMPORAL LOBE EPILEPSY WITH OR WITHOUT HIPPOCAMPAL SCLEROSIS. FURTHERMORE, BY COMPARATIVE ANALYSIS OF EXPRESSION AND PROMOTER METHYLATION, WE IDENTIFY METHYLATION SENSITIVE NON-CODING RNA IN HUMAN TEMPORAL LOBE EPILEPSY. A TOTAL OF 146 PROTEIN-CODING GENES EXHIBITED ALTERED DNA METHYLATION IN TEMPORAL LOBE EPILEPSY HIPPOCAMPUS (N = 9) WHEN COMPARED TO CONTROL (N = 5), WITH 81.5% OF THE PROMOTERS OF THESE GENES DISPLAYING HYPERMETHYLATION. UNIQUE METHYLATION PROFILES WERE EVIDENT IN TEMPORAL LOBE EPILEPSY WITH OR WITHOUT HIPPOCAMPAL SCLEROSIS, IN ADDITION TO A COMMON METHYLATION PROFILE REGARDLESS OF PATHOLOGY GRADE. GENE ONTOLOGY TERMS ASSOCIATED WITH DEVELOPMENT, NEURON REMODELLING AND NEURON MATURATION WERE OVER-REPRESENTED IN THE METHYLATION PROFILE OF WATSON GRADE 1 SAMPLES (MILD HIPPOCAMPAL SCLEROSIS). IN ADDITION TO GENES ASSOCIATED WITH NEURONAL, NEUROTRANSMITTER/SYNAPTIC TRANSMISSION AND CELL DEATH FUNCTIONS, DIFFERENTIAL HYPERMETHYLATION OF GENES ASSOCIATED WITH TRANSCRIPTIONAL REGULATION WAS EVIDENT IN TEMPORAL LOBE EPILEPSY, BUT OVERALL FEW GENES PREVIOUSLY ASSOCIATED WITH EPILEPSY WERE AMONG THE DIFFERENTIALLY METHYLATED. FINALLY, A PANEL OF 13, METHYLATION-SENSITIVE MICRORNA WERE IDENTIFIED IN TEMPORAL LOBE EPILEPSY INCLUDING MIR27A, MIR-193A-5P (MIR193A) AND MIR-876-3P (MIR876), AND THE DIFFERENTIAL METHYLATION OF LONG NON-CODING RNA DOCUMENTED FOR THE FIRST TIME. THE PRESENT STUDY THEREFORE REPORTS SELECT, GENOME-WIDE DNA METHYLATION CHANGES IN HUMAN TEMPORAL LOBE EPILEPSY THAT MAY CONTRIBUTE TO THE MOLECULAR ARCHITECTURE OF THE EPILEPTIC BRAIN. 2015 6 2654 34 EPILEPSY PROGRESSION IS ASSOCIATED WITH CUMULATIVE DNA METHYLATION CHANGES IN INFLAMMATORY GENES. MESIAL TEMPORAL LOBE EPILEPSY WITH HIPPOCAMPAL SCLEROSIS (MTLE-HS) IS THE MOST COMMON FOCAL EPILEPSY IN ADULTS. IT IS CHARACTERIZED BY ALARMING RATES OF PHARMACORESISTANCE. EPILEPTOGENESIS IS ASSOCIATED WITH THE OCCURRENCE OF EPIGENETIC ALTERATIONS, AND THE FEW EPIGENETIC STUDIES CARRIED OUT IN MTLE-HS HAVE MAINLY FOCUSED ON THE HIPPOCAMPUS. IN THIS STUDY, WE OBTAINED THE DNA METHYLATION PROFILES FROM BOTH THE HIPPOCAMPUS AND ANTERIOR TEMPORAL NEOCORTEX OF MTLE-HS PATIENTS SUBJECTED TO RESECTIVE EPILEPSY SURGERY AND AUTOPSIED NON-EPILEPTIC CONTROLS. WE ASSESSED THE PROGRESSIVE NATURE OF DNA METHYLATION CHANGES IN RELATION TO EPILEPSY DURATION. WE IDENTIFIED SIGNIFICANTLY ALTERED HIPPOCAMPAL DNA METHYLATION PATTERNS ENCOMPASSING MULTIPLE PATHWAYS KNOWN TO BE INVOLVED IN EPILEPTOGENESIS. DNA METHYLATION CHANGES WERE EVEN MORE STRIKING IN THE NEOCORTEX, WHEREIN PATHOGENIC PATHWAYS AND GENES WERE COMMON TO BOTH TISSUES. MOST IMPORTANTLY, DNA METHYLATION CHANGES AT MANY GENOMIC SITES VARIED SIGNIFICANTLY WITH EPILEPSY DURATION. SUCH PROGRESSIVE CHANGES WERE ASSOCIATED WITH INFLAMMATION-RELATED GENES IN THE HIPPOCAMPUS. OUR RESULTS SUGGEST THAT THE NEOCORTEX, RELATIVELY SPARED OF EXTENSIVE HISTOPATHOLOGICAL DAMAGE, MAY ALSO BE INVOLVED IN EPILEPSY DEVELOPMENT. THESE RESULTS ALSO OPEN THE POSSIBILITY THAT THE OBSERVED NEOCORTICAL IMPAIRMENT COULD REPRESENT A PRELIMINARY STAGE OF EPILEPTOGENESIS BEFORE THE ESTABLISHMENT OF CHRONIC LESIONS OR A CONSEQUENCE OF PROLONGED SEIZURE EXPOSURE. OUR TWO-TISSUE MULTI-LEVEL CHARACTERIZATION OF THE MTLE-HS DNA METHYLOME SUGGESTS THE OCCURRENCE OF A SELF-PROPAGATING INFLAMMATORY WAVE OF EPIGENETIC DYSREGULATION. 2022 7 2057 32 EPIGENETIC CONTROL OF EPILEPSY TARGET GENES CONTRIBUTES TO A CELLULAR MEMORY OF EPILEPTOGENESIS IN CULTURED RAT HIPPOCAMPAL NEURONS. HYPERSYNCHRONOUS NEURONAL EXCITATION MANIFESTS CLINICALLY AS SEIZURE (ICTOGENESIS), AND MAY RECUR SPONTANEOUSLY AND REPETITIVELY AFTER A VARIABLE LATENCY PERIOD (EPILEPTOGENESIS). DESPITE TREMENDOUS RESEARCH EFFORTS TO DESCRIBE MOLECULAR PATHWAYS AND SIGNATURES OF EPILEPTOGENESIS, MOLECULAR PATHOMECHANISMS LEADING TO CHRONIC EPILEPSY REMAIN TO BE CLARIFIED. WE HYPOTHESIZED THAT EPIGENETIC MODIFICATIONS MAY FORM THE BASIS FOR A CELLULAR MEMORY OF EPILEPTOGENESIS, AND USED A PRIMARY NEURONAL CELL CULTURE MODEL OF THE RAT HIPPOCAMPUS TO STUDY THE TRANSLATION OF MASSIVE NEURONAL EXCITATION INTO PERSISTING CHANGES OF EPIGENETIC SIGNATURES AND PRO-EPILEPTOGENIC TARGET GENE EXPRESSION. INCREASED SPONTANEOUS ACTIVATION OF CULTURED NEURONS WAS DETECTED 3 AND 7 DAYS AFTER STIMULATION WITH 10 MUM GLUTAMATE WHEN COMPARED TO SHAM-TREATED TIME-MATCHED CONTROLS USING CALCIUM-IMAGING IN VITRO. CHROMATIN-IMMUNOPRECIPITATION EXPERIMENTS REVEALED SHORT-TERM (3 H, 7 H, AND 24 H) AND LONG-TERM (3 D AND 2 WEEKS) CHANGES IN HISTONE MODIFICATIONS, WHICH WERE DIRECTLY LINKED TO DECREASED EXPRESSION OF TWO SELECTED EPILEPSY TARGET GENES, E.G. EXCITATORY GLUTAMATE RECEPTOR GENES GRIA2 AND GRIN2A. INCREASED PROMOTER METHYLATION OBSERVED 4 WEEKS AFTER GLUTAMATE STIMULATION AT RESPECTIVE GENES SUGGESTED LONG-TERM REPRESSION OF GRIA2 AND GRIN2A GENES. INHIBITION OF GLUTAMATERGIC ACTIVATION OR BLOCKING THE PROPAGATION OF ACTION POTENTIALS IN CULTURED NEURONS RESCUED ALTERED GENE EXPRESSION AND REGULATORY EPIGENETIC MODIFICATIONS. OUR DATA SUPPORT THE CONCEPT OF A CELLULAR MEMORY OF EPILEPTOGENESIS AND PERSISTING EPIGENETIC MODIFICATIONS OF EPILEPSY TARGET GENES, WHICH ARE ABLE TO TURN NORMAL INTO PRO-EPILEPTIC NEURONS AND CIRCUITS. 2017 8 213 32 ACUTE AND CHRONIC ELECTROCONVULSIVE SEIZURES (ECS) DIFFERENTIALLY REGULATE THE EXPRESSION OF EPIGENETIC MACHINERY IN THE ADULT RAT HIPPOCAMPUS. BACKGROUND: ELECTROCONVULSIVE SEIZURE TREATMENT IS A FAST-ACTING ANTIDEPRESSANT THERAPY THAT EVOKES RAPID TRANSCRIPTIONAL, NEUROGENIC, AND BEHAVIORAL CHANGES. EPIGENETIC MECHANISMS CONTRIBUTE TO ALTERED GENE REGULATION, WHICH UNDERLIES THE NEUROGENIC AND BEHAVIORAL EFFECTS OF ELECTROCONVULSIVE SEIZURE. WE HYPOTHESIZED THAT ELECTROCONVULSIVE SEIZURE MAY MODULATE THE EXPRESSION OF EPIGENETIC MACHINERY, THUS ESTABLISHING POTENTIAL ALTERATIONS IN THE EPIGENETIC LANDSCAPE. METHODS: WE EXAMINED THE INFLUENCE OF ACUTE AND CHRONIC ELECTROCONVULSIVE SEIZURE ON THE GENE EXPRESSION OF HISTONE MODIFIERS, NAMELY HISTONE ACETYLTRANSFERASES, HISTONE DEACETYLASES, HISTONE METHYLTRANSFERASES, AND HISTONE (LYSINE) DEMETHYLASES AS WELL AS DNA MODIFYING ENZYMES, INCLUDING DNA METHYLTRANSFERASES, DNA DEMETHYLASES, AND METHYL-CPG-BINDING PROTEINS IN THE HIPPOCAMPI OF ADULT MALE WISTAR RATS USING QUANTITATIVE REAL TIME-PCR ANALYSIS. FURTHER, WE EXAMINED THE INFLUENCE OF ACUTE AND CHRONIC ELECTROCONVULSIVE SEIZURE ON GLOBAL AND RESIDUE-SPECIFIC HISTONE ACETYLATION AND METHYLATION LEVELS WITHIN THE HIPPOCAMPUS, A BRAIN REGION IMPLICATED IN THE CELLULAR AND BEHAVIORAL EFFECTS OF ELECTROCONVULSIVE SEIZURE. RESULTS: ACUTE AND CHRONIC ELECTROCONVULSIVE SEIZURE INDUCED A PRIMARILY UNIQUE, AND IN CERTAIN CASES BIDIRECTIONAL, REGULATION OF HISTONE AND DNA MODIFIERS, AND METHYL-CPG-BINDING PROTEINS, WITH AN OVERLAPPING PATTERN OF GENE REGULATION RESTRICTED TO SIRT4, MLL3, JMJD3, GADD45B, TET2, AND TET3. GLOBAL HISTONE ACETYLATION AND METHYLATION LEVELS WERE PREDOMINANTLY UNCHANGED, WITH THE EXCEPTION OF A SIGNIFICANT DECLINE IN H3K9 ACETYLATION IN THE HIPPOCAMPUS FOLLOWING CHRONIC ELECTROCONVULSIVE SEIZURE. CONCLUSIONS: ELECTROCONVULSIVE SEIZURE TREATMENT EVOKES THE TRANSCRIPTIONAL REGULATION OF SEVERAL HISTONE AND DNA MODIFIERS, AND METHYL-CPG-BINDING PROTEINS WITHIN THE HIPPOCAMPUS, WITH A PREDOMINANTLY DISTINCT PATTERN OF REGULATION INDUCED BY ACUTE AND CHRONIC ELECTROCONVULSIVE SEIZURE. 2016 9 3647 32 INCREASED REELIN PROMOTER METHYLATION IS ASSOCIATED WITH GRANULE CELL DISPERSION IN HUMAN TEMPORAL LOBE EPILEPSY. MESIAL TEMPORAL SCLEROSIS (MTS) IS THE MOST COMMON LESION IN CHRONIC, INTRACTABLE TEMPORAL LOBE EPILEPSIES (TLE) AND CHARACTERIZED BY SEGMENTAL NEURONAL CELL LOSS IN MAJOR HIPPOCAMPAL SEGMENTS. ANOTHER HISTOPATHOLOGICAL HALLMARK INCLUDES GRANULE CELL DISPERSION (GCD), AN ARCHITECTURAL DISTURBANCE OF THE DENTATE GYRUS ENCOUNTERED IN APPROXIMATELY 50% OF PATIENTS WITH MESIAL TEMPORAL SCLEROSIS. REELIN, WHICH PLAYS A KEY ROLE DURING HIPPOCAMPAL DEVELOPMENT AND MAINTENANCE OF LAMINAR ORGANIZATION, IS SYNTHESIZED AND RELEASED BY CAJAL-RETZIUS CELLS OF THE DENTATE MOLECULAR LAYER, AND PREVIOUS STUDIES HAVE SHOWN THAT REELIN TRANSCRIPT LEVELS ARE DOWNREGULATED IN HUMAN TEMPORAL LOBE EPILEPSIES SPECIMENS. TO INVESTIGATE WHETHER EPIGENETIC SILENCING BY REELIN PROMOTER METHYLATION MAY BE AN UNDERLYING PATHOGENETIC MECHANISM OF GCD, DNA WAS HARVESTED FROM 3 MICRODISSECTED HIPPOCAMPAL SUBREGIONS (I.E. MOLECULAR AND GRANULE CELL LAYERS OF THE DENTATE GYRUS AND PRESUBICULUM) FROM 8 MTS SPECIMENS WITH GCD, 5 TLE SAMPLES WITHOUT GCD, AND 3 AUTOPSY CONTROLS. PROMOTER METHYLATION WAS ANALYZED AFTER BISULFITE TREATMENT, CLONING, AND DIRECT SEQUENCING; IMMUNOHISTOCHEMISTRY WAS PERFORMED TO IDENTIFY CAJAL-RETZIUS CELLS. REELIN PROMOTER METHYLATION WAS FOUND TO BE GREATER IN TLE SPECIMENS THAN IN CONTROLS; PROMOTER METHYLATION CORRELATED WITH GCD AMONG TLE SPECIMENS (P < 0.0002). NO OTHER CLINICAL OR HISTOPATHOLOGICAL PARAMETER (I.E. SEX, AGE, SEIZURE DURATION, MEDICATION OR EXTENT, OF MTS) CORRELATED WITH PROMOTER METHYLATION. THESE DATA SUPPORT A COMPROMISED REELIN-SIGNALING PATHWAY AND IDENTIFY PROMOTER METHYLATION AS AN EPIGENETIC MECHANISM IN THE PATHOGENESIS OF TLE. 2009 10 2297 31 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 11 1301 34 DEEP SEQUENCING REVEALS INCREASED DNA METHYLATION IN CHRONIC RAT EPILEPSY. EPILEPSY IS A FREQUENT NEUROLOGICAL DISORDER, ALTHOUGH ONSET AND PROGRESSION OF SEIZURES REMAIN DIFFICULT TO PREDICT IN AFFECTED PATIENTS, IRRESPECTIVE OF THEIR EPILEPTOGENIC CONDITION. PREVIOUS STUDIES IN ANIMAL MODELS AS WELL AS HUMAN EPILEPTIC BRAIN TISSUE REVEALED A REMARKABLY DIVERSE PATTERN OF GENE EXPRESSION IMPLICATING EPIGENETIC CHANGES TO CONTRIBUTE TO DISEASE PROGRESSION. HERE WE MAPPED FOR THE FIRST TIME GLOBAL DNA METHYLATION PATTERNS IN CHRONIC EPILEPTIC RATS AND CONTROLS. USING METHYL-CPG CAPTURE ASSOCIATED WITH MASSIVE PARALLEL SEQUENCING (METHYL-SEQ) WE REPORT THE GENOMIC METHYLATION SIGNATURE OF THE CHRONIC EPILEPTIC STATE. WE OBSERVED A PREDOMINANT INCREASE, RATHER THAN LOSS OF DNA METHYLATION IN CHRONIC RAT EPILEPSY. ABERRANT METHYLATION PATTERNS WERE INVERSELY CORRELATED WITH GENE EXPRESSION CHANGES USING MRNA SEQUENCING FROM SAME ANIMALS AND TISSUE SPECIMENS. ADMINISTRATION OF A KETOGENIC, HIGH-FAT, LOW-CARBOHYDRATE DIET ATTENUATED SEIZURE PROGRESSION AND AMELIORATED DNA METHYLATION MEDIATED CHANGES IN GENE EXPRESSION. THIS IS THE FIRST REPORT OF UNSUPERVISED CLUSTERING OF AN EPIGENETIC MARK BEING USED IN EPILEPSY RESEARCH TO SEPARATE EPILEPTIC FROM NON-EPILEPTIC ANIMALS AS WELL AS FROM ANIMALS RECEIVING ANTI-CONVULSIVE DIETARY TREATMENT. WE FURTHER DISCUSS THE POTENTIAL IMPACT OF EPIGENETIC CHANGES AS A PATHOGENIC MECHANISM OF EPILEPTOGENESIS. 2013 12 6411 36 THE SITE SPECIFIC DEMETHYLATION IN THE 5'-REGULATORY AREA OF NMDA RECEPTOR 2B SUBUNIT GENE ASSOCIATED WITH CIE-INDUCED UP-REGULATION OF TRANSCRIPTION. BACKGROUND: THE NMDA RECEPTOR REPRESENTS A PARTICULARLY IMPORTANT SITE OF ETHANOL ACTION IN THE CNS. WE RECENTLY REPORTED THAT NMDA RECEPTOR 2B (NR2B) GENE EXPRESSION WAS PERSISTENTLY UP-REGULATED FOLLOWING CHRONIC INTERMITTENT ETHANOL (CIE) TREATMENT. INCREASING EVIDENCE THAT EPIGENETIC MECHANISMS ARE INVOLVED IN DYNAMIC AND LONG-LASTING REGULATION OF GENE EXPRESSION IN MULTIPLE NEUROADAPTIVE PROCESSES PROMPTED US TO INVESTIGATE THE ROLE OF DNA METHYLATION IN MEDIATING CIE-INDUCED UP-REGULATION OF NR2B GENE TRANSCRIPTION. TO DISSECT THE CHANGES OF DNA METHYLATION IN THE NR2B GENE, WE HAVE SCREENED A LARGE NUMBER OF CPG SITES WITHIN ITS 5'-REGULATORY AREA FOLLOWING CIE TREATMENT. METHODS: PRIMARY CORTICAL CULTURED NEURONS WERE SUBJECTED TO ETHANOL TREATMENT IN A CIE PARADIGM. BISULFITE CONVERSION FOLLOWED BY PYROSEQUENCING WAS USED FOR QUANTITATIVE MEASUREMENT AND ANALYSIS OF CPG METHYLATION STATUS WITHIN THE 5'-REGULATORY AREA OF THE NR2B GENE; CHROMATIN IMMUNOPRECIPITATION (CHIP) ASSAY WAS USED TO EXAMINE DNA LEVELS ASSOCIATED WITH METHYLATION AND TRANSCRIPTION FACTOR BINDING. ELECTROPHORETIC MOBILITY SHIFT ASSAY (EMSA) AND IN VITRO DNA METHYLATION ASSAYS WERE PERFORMED TO DETERMINE THE DIRECT IMPACT OF DNA METHYLATION ON THE INTERACTION BETWEEN DNA AND TRANSCRIPTION FACTOR AND PROMOTER ACTIVITY. RESULTS: ANALYSIS OF INDIVIDUAL CPG METHYLATION SITES WITHIN THE NR2B 5'REGULATORY AREA REVEALED THREE REGIONS WITH CLUSTERS OF SITE-SPECIFIC CPG DEMETHYLATION FOLLOWING CIE TREATMENT AND WITHDRAWAL. THIS WAS CONFIRMED BY CHIP SHOWING SIMILAR DECREASES OF METHYLATED DNA IN THE SAME REGIONS. THE CIE-INDUCED DEMETHYLATION IS CHARACTERIZED BY BEING LOCATED NEAR CERTAIN TRANSCRIPTION FACTOR BINDING SEQUENCES, AP-1 AND CRE, AND OCCURRED DURING TREATMENT AS WELL AS AFTER ETHANOL WITHDRAWAL. FURTHERMORE, THE INCREASE IN VITRO OF METHYLATED DNA DECREASED TRANSCRIPTION FACTOR BINDING ACTIVITY AND PROMOTER ACTIVITY. AN ADDITIONAL CHIP ASSAY INDICATED THAT THE CIE-INDUCED DNA DEMETHYLATION IS ACCOMPANIED BY INCREASED OCCUPATION BY TRANSCRIPTION FACTORS. CONCLUSIONS: THESE RESULTS SUGGEST AN IMPORTANT ROLE OF DNA DEMETHYLATION IN MEDIATING CIE-INDUCED NR2B GENE UP-REGULATION, THUS IMPLICATING A NOVEL MOLECULAR SITE OF ALCOHOL ACTION. 2010 13 2755 35 EXPRESSION OF CLASS II HISTONE DEACETYLASES IN TWO MOUSE MODELS OF TEMPORAL LOBE EPILEPSY. EPIGENETIC MECHANISMS LIKE ALTERED HISTONE ACETYLATION MAY HAVE A CRUCIAL ROLE IN EPILEPTOGENESIS. IN TWO MOUSE MODELS OF TEMPORAL LOBE EPILEPSY, WE INVESTIGATED CHANGES IN THE EXPRESSION OF CLASS II HISTONE DEACETYLASES (HDAC), A GROUP OF SIGNAL TRANSDUCERS THAT SHUTTLE BETWEEN NUCLEUS AND CYTOPLASM. INTRAHIPPOCAMPAL INJECTION OF KAINIC ACID (KA) INDUCED A STATUS EPILEPTICUS, DEVELOPMENT OF SPONTANEOUS SEIZURES (AFTER 3 DAYS), AND FINALLY CHRONIC EPILEPSY AND GRANULE CELL DISPERSION. EXPRESSION OF CLASS II HDAC MRNAS WAS INVESTIGATED AT DIFFERENT TIME INTERVALS AFTER KA INJECTION IN THE GRANULE CELL LAYERS AND IN SECTORS CA1 AND CA3 CONTRALATERAL TO THE SITE OF KA INJECTION LACKING NEURODEGENERATION. INCREASED EXPRESSION OF HDAC5 AND 9 MRNAS COINCIDED WITH PRONOUNCED GRANULE CELL DISPERSION IN THE KA-INJECTED HIPPOCAMPUS AT LATE INTERVALS (14-28 DAYS AFTER KA) AND EQUALLY AFFECTED BOTH HDAC9 SPLICE VARIANTS. IN CONTRAST, IN THE PILOCARPINE MODEL (SHOWING NO GRANULE CELL DISPERSION), WE OBSERVED DECREASES IN THE EXPRESSION OF HDAC5 AND 9 AT THE SAME TIME INTERVALS. BEYOND THIS, STRIKING SIMILARITIES BETWEEN BOTH TEMPORAL LOBE EPILEPSY MODELS SUCH AS FAST DECREASES IN HDAC7 AND 10 MRNAS DURING THE ACUTE STATUS EPILEPTICUS WERE OBSERVED, NOTABLY ALSO IN THE CONTRALATERAL HIPPOCAMPUS NOT AFFECTED BY NEURODEGENERATION. THE PARTICULAR PATTERNS OF HDAC MRNA EXPRESSION SUGGEST A ROLE IN EPILEPTOGENESIS AND GRANULE CELL DISPERSION. REDUCED EXPRESSION OF HDACS MAY RESULT IN INCREASED EXPRESSION OF PRO- AND ANTICONVULSIVE PROTEINS. ON THE OTHER HAND, EXPORT OF HDACS FROM THE NUCLEUS INTO THE CYTOPLASM COULD ALLOW FOR DEACETYLATION OF CYTOPLASMATIC PROTEINS INVOLVED IN AXONAL AND DENDRITIC REMODELING, LIKE GRANULE CELL DISPERSION. HDAC 5 AND HDAC 9 EXPRESSION IS HIGHLY INCREASED IN GRANULE CELLS OF THE KA-INJECTED HIPPOCAMPUS AND PARALLELS GRANULE CELL DISPERSION. BOTH HDACS ARE THOUGHT TO BE TARGETED TO THE CYTOPLASM AND TO ACT THERE BY DEACETYLATING CYTOPLASMATIC (E.G. CYTOSCELETON-RELATED) PROTEINS. 2016 14 5273 32 PROMOTER METHYLATION AND BDNF AND DAT1 GENE EXPRESSION PROFILES IN PATIENTS WITH DRUG ADDICTION. BACKGROUND: DRUG ADDICTION IS A BRAIN DISORDER THAT HAS NEGATIVE CONSEQUENCES FOR INDIVIDUALS AND SOCIETY. ADDICTIONS ARE CHRONIC RELAPSING DISEASES OF THE BRAIN THAT ARE CAUSED BY DIRECT DRUG-INDUCED EFFECTS AND PERSEVERING NEUROADAPTATIONS AT THE EPIGENETIC, NEUROPEPTIDE AND NEUROTRANSMITTER LEVELS. BECAUSE THE DOPAMINERGIC SYSTEM HAS A SIGNIFICANT ROLE IN DRUG ABUSE, THE PURPOSE OF THIS STUDY WAS TO ANALYZE THE METHYLATION AND EXPRESSION PROFILE OF BRAIN-DERIVED NEUROTROPHIC FACTOR (BDNF) AND DOPAMINE TRANSPORTER (DAT1) GENES IN INDIVIDUALS WITH DRUG ADDICTION. MATERIALS AND METHODS: BDNF AND DAT1 PROMOTER METHYLATION WERE INVESTIGATED WITH A METHYLATION-SPECIFIC POLYMERASE CHAIN REACTION (PCR) TECHNIQUE IN BLOOD SAMPLES FROM 75 INDIVIDUALS WITH DRUG ADDICTION AND 65 HEALTHY CONTROLS. THE EXPRESSION LEVELS OF BDNF AND DAT1 WERE ASSESSED IN 12 MRNA SAMPLES FROM THE BLOOD OF PATIENTS AND COMPARED TO THE SAMPLES OF HEALTHY CONTROLS (N = 12) WITH REAL-TIME QUANTITATIVE REVERSE TRANSCRIPTION PCR. RESULTS: NO SIGNIFICANT DIFFERENCES WERE FOUND IN THE METHYLATION OF BDNF AND DAT1 BETWEEN PATIENTS AND CONTROLS, BUT THE RELATIVE LEVELS OF EXPRESSION OF BDNF AND DAT1 MRNA DIFFERED SIGNIFICANTLY IN THE PATIENTS COMPARED TO CONTROLS (P < 0.0001). CONCLUSION: THESE RESULTS SHOWED THAT THE METHYLATION STATUS OF THE BDNF AND DAT1 GENES HAD NO SIGNIFICANT FUNCTION IN THE PROCESSES OF DRUG ADDICTION. 2015 15 4014 35 LOW-DOSE CD INDUCES HEPATIC GENE HYPERMETHYLATION, ALONG WITH THE PERSISTENT REDUCTION OF CELL DEATH AND INCREASE OF CELL PROLIFERATION IN RATS AND MICE. BACKGROUND: CADMIUM (CD) IS CLASSIFIED AS A HUMAN CARCINOGEN PROBABLY ASSOCIATED WITH EPIGENETIC CHANGES. DNA METHYLATION IS ONE OF EPIGENETIC MECHANISMS BY WHICH CELLS CONTROL GENE EXPRESSION. THEREFORE, THE PRESENT STUDY GENOME-WIDELY SCREENED THE METHYLATION-ALTERED GENES IN THE LIVER OF RATS PREVIOUSLY EXPOSED TO LOW-DOSE CD. METHODOLOGY PRINCIPAL FINDINGS: RATS WERE EXPOSED TO CD AT 20 NMOL/KG EVERY OTHER DAY FOR 4 WEEKS AND GENE METHYLATION WAS ANALYZED AT THE 48(TH) WEEK WITH METHYLATED DNA IMMUNOPRECIPITATION-CPG ISLAND MICROARRAY. AMONG THE 1629 ALTERED GENES, THERE WERE 675 GENES WHOSE PROMOTER CPG ISLANDS (CGIS) WERE HYPERMETHYLATED, 899 GENES WHOSE PROMOTER CGIS WERE HYPOMETHYLATED, AND 55 GENES WHOSE PROMOTER CGIS WERE MIXED WITH HYPER- AND HYPO-METHYLATION. CASPASE-8 GENE PROMOTER CGIS AND TNF GENE PROMOTER CGIS WERE HYPERMETHYLATED AND HYPOMETHYLATED, RESPECTIVELY, ALONG WITH A LOW APOPTOSIS RATE IN CD-TREATED RAT LIVERS. TO LINK THE ABERRANT METHYLATION OF CASPASE-8 AND TNF GENES TO THE LOW APOPTOSIS INDUCED BY LOW-DOSE CD, MICE WERE GIVEN CHRONIC EXPOSURE TO LOW-DOSE CD WITH AND WITHOUT METHYLATION INHIBITOR (5-AZA-2'-DEOXYCTIDENE, 5-AZA). AT THE 48(TH) WEEK AFTER CD EXPOSURE, LIVERS FROM CD-TREATED MICE DISPLAYED THE INCREASED CASPASE-8 CGI METHYLATION AND DECREASED CASPASE-8 PROTEIN EXPRESSION, ALONG WITH SIGNIFICANT INCREASES IN CELL PROLIFERATION AND OVEREXPRESSION OF TGF-BETA1 AND CYTOKERATIN 8/18 (THE LATTER IS A NEW MARKER OF MOUSE LIVER PRENEOPLASTIC LESIONS), ALL WHICH WERE PREVENTED BY 5-AZA TREATMENT. CONCLUSION/SIGNIFICANCE: THESE RESULTS SUGGEST THAT CD-INDUCED GLOBAL GENE HYPERMETHYLATION, MOST LIKELY CASPASE-8 GENE PROMOTER HYPERMETHYLATION THAT DOWN-REGULATED ITS EXPRESSION, LEADING TO THE DECREASED HEPATIC APOPTOSIS AND INCREASED PRENEOPLASTIC LESIONS. 2012 16 1718 30 DYSREGULATED LONG NON-CODING RNAS IN THE TEMPORAL LOBE EPILEPSY MOUSE MODEL. PURPOSE: TO PERFORM COMPREHENSIVE PROFILING OF LONG NON-CODING RNAS (LNCRNAS) IN TEMPORAL LOBE EPILEPSY. METHODS: WE PERFORMED EXTENSIVE PROFILING OF LNCRNAS AND MRNAS IN THE MOUSE PILOCARPINE MODEL IN SPECIFIC BRAIN REGIONS, THE HIPPOCAMPUS AND CORTEX, AND COMPARED THE RESULTS TO THOSE OF THE CONTROL MOUSE. DIFFERENTIALLY EXPRESSED LNCRNAS AND MRNAS WERE IDENTIFIED WITH A MICROARRAY ANALYSIS (ARRAYSTAR MOUSE LNCRNA EXPRESSION MICROARRAY V3.0). THEN, GENE ONTOLOGY (GO) AND PATHWAY ANALYSIS WERE PERFORMED TO INVESTIGATE THE POTENTIAL ROLES OF THE DIFFERENTIALLY EXPRESSED MRNAS IN THE PILOCARPINE MODEL. PROTEIN-PROTEIN INTERACTIONS TRANSCRIBED BY DYSREGULATED MRNAS WITH/WITHOUT CO-DYSREGULATED LNCRNAS WERE ANALYZED USING STRING V10 (HTTP://STRING-DB.ORG/). RESULTS: A TOTAL OF 22 AND 83 LNCRNAS WERE UP- AND DOWN-REGULATED (>/=2.0-FOLD, ALL P < .05), RESPECTIVELY, IN THE HIPPOCAMPUS OF THE EPILEPSY MODEL, WHILE 46 AND 659 LNCRNAS WERE UP- AND DOWN-REGULATED, RESPECTIVELY, IN THE CORTEX OF THE EPILEPSY MODEL. GO AND PATHWAY ANALYSIS REVEALED THAT THE DYSREGULATED MRNAS WERE CLOSELY ASSOCIATED WITH A PROCESS ALREADY KNOWN TO BE INVOLVED IN EPILEPTOGENESIS: ACUTE INFLAMMATION, CALCIUM ION REGULATION, EXTRACELLULAR MATRIX REMODELING, AND NEURONAL DIFFERENTIATION. AMONG THE LNCRNAS, WE IDENTIFIED 10 LNCRNAS COMMONLY DYSREGULATED WITH CORRESPONDING MRNAS IN THE CORTEX. THE STRING ANALYSIS SHOWED THAT THE DYSREGULATED MRNAS WERE INTERCONNECTED AROUND TWO CENTERS: THE MTOR PATHWAY-RELATED GENES AND REST PATHWAY-RELATED GENES. CONCLUSION: LNCRNAS WERE DYSREGULATED IN THE PILOCARPINE MOUSE MODEL ACCORDING TO THE BRAIN REGIONS OF THE HIPPOCAMPUS AND CORTEX. THE DYSREGULATED LNCRNAS WITH CO-DYSREGULATED MRNAS MIGHT BE POSSIBLE THERAPEUTIC TARGETS FOR THE EPIGENETIC REGULATION OF CHRONIC EPILEPSY. 2018 17 345 39 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 18 6419 31 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 19 433 37 ANTIDEPRESSANT TREATMENT IS ASSOCIATED WITH EPIGENETIC ALTERATIONS OF HOMER1 PROMOTER IN A MOUSE MODEL OF CHRONIC DEPRESSION. BACKGROUND: UNDERSTANDING THE NEUROBIOLOGY OF DEPRESSION AND THE MECHANISM OF ACTION OF THERAPEUTIC MEASURES IS CURRENTLY A RESEARCH PRIORITY. WE HAVE SHOWN THAT THE EXPRESSION OF THE SYNAPTIC PROTEIN HOMER1A CORRELATES WITH DEPRESSION-LIKE BEHAVIOR AND ITS INDUCTION IS A COMMON MECHANISM OF ACTION OF DIFFERENT ANTIDEPRESSANT TREATMENTS. HOWEVER, THE MECHANISM OF HOMER1A REGULATION IS STILL UNKNOWN. METHODS: WE COMBINED THE CHRONIC DESPAIR MOUSE MODEL (CDM) OF CHRONIC DEPRESSION WITH DIFFERENT ANTIDEPRESSANT TREATMENTS. DEPRESSION-LIKE BEHAVIOR WAS CHARACTERIZED BY FORCED SWIM AND TAIL SUSPENSION TESTS, AND VIA AUTOMATIC MEASUREMENT OF SUCROSE PREFERENCE IN INTELLICAGE. THE HOMER1 MRNA EXPRESSION AND PROMOTER DNA METHYLATION WERE ANALYZED IN CORTEX AND PERIPHERAL BLOOD BY QRT-PCR AND PYROSEQUENCING. RESULTS: CDM MICE SHOW DECREASED HOMER1A AND HOMER1B/C MRNA EXPRESSION IN CORTEX AND BLOOD SAMPLES, WHILE CHRONIC TREATMENT WITH IMIPRAMINE AND FLUOXETINE OR ACUTE KETAMINE APPLICATION INCREASES THEIR LEVEL ONLY IN THE CORTEX. THE QUANTITATIVE ANALYSES OF THE METHYLATION OF 7 CPG SITES, LOCATED ON THE HOMER1 PROMOTER REGION CONTAINING SEVERAL CRE BINDING SITES, SHOW A SIGNIFICANT INCREASE IN DNA METHYLATION IN THE CORTEX OF CDM MICE. IN CONTRAST, ANTIDEPRESSANT TREATMENTS REDUCE THE METHYLATION LEVEL. LIMITATIONS: HOMER1 EXPRESSION AND PROMOTOR METHYLATION WERE NOT ANALYZED IN DIFFERENT BLOOD CELL TYPES. OTHER CPG SITES OF HOMER1 PROMOTER SHOULD BE INVESTIGATED IN FUTURE STUDIES. OUR EXPERIMENTAL APPROACH DOES NOT DISTINGUISH BETWEEN METHYLATION AND HYDROXYMETHYLATION. CONCLUSIONS: WE DEMONSTRATE THAT STRESS-INDUCED DEPRESSION-LIKE BEHAVIOR AND ANTIDEPRESSANT TREATMENTS ARE ASSOCIATED WITH EPIGENETIC ALTERATIONS OF HOMER1 PROMOTER, PROVIDING NEW INSIGHTS INTO THE MECHANISM OF ANTIDEPRESSANT TREATMENT. 2021 20 5972 25 TET REPRESSION AND INCREASED DNMT ACTIVITY SYNERGISTICALLY INDUCE ABERRANT DNA METHYLATION. CHRONIC INFLAMMATION IS DEEPLY INVOLVED IN VARIOUS HUMAN DISORDERS, SUCH AS CANCER, NEURODEGENERATIVE DISORDERS, AND METABOLIC DISORDERS. INDUCTION OF EPIGENETIC ALTERATIONS, ESPECIALLY ABERRANT DNA METHYLATION, IS ONE OF THE MAJOR MECHANISMS, BUT HOW IT IS INDUCED IS STILL UNCLEAR. HERE, WE FOUND THAT EXPRESSION OF TET GENES, METHYLATION ERASERS, WAS DOWNREGULATED IN INFLAMED MOUSE AND HUMAN TISSUES, AND THAT THIS WAS CAUSED BY UPREGULATION OF TET-TARGETING MIRNAS SUCH AS MIR20A, MIR26B, AND MIR29C, LIKELY DUE TO ACTIVATION OF NF-KAPPAB SIGNALING DOWNSTREAM OF IL-1BETA AND TNF-ALPHA. HOWEVER, TET KNOCKDOWN INDUCED ONLY MILD ABERRANT METHYLATION. NITRIC OXIDE (NO), PRODUCED BY NOS2, ENHANCED ENZYMATIC ACTIVITY OF DNA METHYLTRANSFERASES (DNMTS), METHYLATION WRITERS, AND NO EXPOSURE INDUCED MINIMAL ABERRANT METHYLATION. IN CONTRAST, A COMBINATION OF TET KNOCKDOWN AND NO EXPOSURE SYNERGISTICALLY INDUCED ABERRANT METHYLATION, INVOLVING GENOMIC REGIONS NOT METHYLATED BY EITHER ALONE. THE RESULTS SHOWED THAT A VICIOUS COMBINATION OF TET REPRESSION, DUE TO NF-KAPPAB ACTIVATION, AND DNMT ACTIVATION, DUE TO NO PRODUCTION, IS RESPONSIBLE FOR ABERRANT METHYLATION INDUCTION IN HUMAN TISSUES. 2020