1 351 149 ALTERED ENDOTHELIAL DYSFUNCTION-RELATED MIRS IN PLASMA FROM ME/CFS PATIENTS. MYALGIC ENCEPHALOMYELITIS/CHRONIC FATIGUE SYNDROME (ME/CFS) IS A COMPLEX DISEASE CHARACTERIZED BY UNEXPLAINED DEBILITATING FATIGUE. ALTHOUGH THE ETIOLOGY IS UNKNOWN, EVIDENCE SUPPORTS IMMUNOLOGICAL ABNORMALITIES, SUCH AS PERSISTENT INFLAMMATION AND IMMUNE-CELL ACTIVATION, IN A SUBSET OF PATIENTS. SINCE THE INTERPLAY BETWEEN INFLAMMATION AND VASCULAR ALTERATIONS IS WELL-ESTABLISHED IN OTHER DISEASES, ENDOTHELIAL DYSFUNCTION HAS EMERGED AS ANOTHER PLAYER IN ME/CFS PATHOGENESIS. ENDOTHELIAL NITRIC OXIDE SYNTHASE (ENOS) GENERATES NITRIC OXIDE (NO) THAT MAINTAINS ENDOTHELIAL HOMEOSTASIS. ENOS IS ACTIVATED BY SILENT INFORMATION REGULATOR 1 (SIRT1), AN ANTI-INFLAMMATORY PROTEIN. DESPITE ITS RELEVANCE, NO STUDY HAS ADDRESSED THE SIRT1/ENOS AXIS IN ME/CFS. THE INTEREST IN CIRCULATING MICRORNAS (MIRS) AS POTENTIAL BIOMARKERS IN ME/CFS HAS INCREASED IN RECENT YEARS. ACCORDINGLY, WE ANALYZE A SET OF MIRS REPORTED TO MODULATE THE SIRT1/ENOS AXIS USING PLASMA FROM ME/CFS PATIENTS. OUR RESULTS SHOW THAT MIR-21, MIR-34A, MIR-92A, MIR-126, AND MIR-200C ARE JOINTLY INCREASED IN ME/CFS PATIENTS COMPARED TO HEALTHY CONTROLS. A SIMILAR FINDING WAS OBTAINED WHEN ANALYZING PUBLIC MIR DATA ON PERIPHERAL BLOOD MONONUCLEAR CELLS. BIOINFORMATICS ANALYSIS SHOWS THAT ENDOTHELIAL FUNCTION-RELATED SIGNALING PATHWAYS ARE ASSOCIATED WITH THESE MIRS, INCLUDING OXIDATIVE STRESS AND OXYGEN REGULATION. INTERESTINGLY, HISTONE DEACETYLASE 1, A PROTEIN RESPONSIBLE FOR EPIGENETIC REGULATIONS, REPRESENTED THE MOST RELEVANT NODE WITHIN THE NETWORK. IN CONCLUSION, OUR STUDY PROVIDES A BASIS TO FIND ENDOTHELIAL DYSFUNCTION-RELATED BIOMARKERS AND EXPLORE NOVEL TARGETS IN ME/CFS. 2021 2 3041 35 GENOME-EPIGENOME INTERACTIONS ASSOCIATED WITH MYALGIC ENCEPHALOMYELITIS/CHRONIC FATIGUE SYNDROME. MYALGIC ENCEPHALOMYELITIS/CHRONIC FATIGUE SYNDROME (ME/CFS) IS A COMPLEX DISEASE OF UNKNOWN ETIOLOGY. MULTIPLE STUDIES POINT TO DISRUPTIONS IN IMMUNE FUNCTIONING IN ME/CFS PATIENTS AS WELL AS SPECIFIC GENETIC POLYMORPHISMS AND ALTERATIONS OF THE DNA METHYLOME IN LYMPHOCYTES. HOWEVER, POTENTIAL INTERACTIONS BETWEEN DNA METHYLATION AND GENETIC BACKGROUND IN RELATION TO ME/CFS HAVE NOT BEEN EXAMINED. IN THIS STUDY WE EXPLORED THIS ASSOCIATION BY CHARACTERIZING THE EPIGENETIC (~480 THOUSAND CPG LOCI) AND GENETIC (~4.3 MILLION SNPS) VARIATION BETWEEN COHORTS OF ME/CFS PATIENTS AND HEALTHY CONTROLS. WE FOUND SIGNIFICANT ASSOCIATIONS OF DNA METHYLATION STATES IN T-LYMPHOCYTES AT SEVERAL CPG LOCI AND REGIONS WITH ME/CFS PHENOTYPE. THESE METHYLATION ANOMALIES ARE IN CLOSE PROXIMITY TO GENES INVOLVED WITH IMMUNE FUNCTION AND CELLULAR METABOLISM. FINALLY, WE FOUND SIGNIFICANT CORRELATIONS OF GENOTYPES WITH METHYLATION MODIFICATIONS ASSOCIATED WITH ME/CFS. THE FINDINGS FROM THIS STUDY HIGHLIGHT THE ROLE OF EPIGENETIC AND GENETIC INTERACTIONS IN COMPLEX DISEASES, AND SUGGEST SEVERAL GENETIC AND EPIGENETIC ELEMENTS POTENTIALLY INVOLVED IN THE MECHANISMS OF DISEASE IN ME/CFS. 2018 3 2207 52 EPIGENETIC MODIFICATIONS AND GLUCOCORTICOID SENSITIVITY IN MYALGIC ENCEPHALOMYELITIS/CHRONIC FATIGUE SYNDROME (ME/CFS). BACKGROUND: MYALGIC ENCEPHALOMYELITIS/CHRONIC FATIGUE SYNDROME (ME/CFS) IS A DEBILITATING IDIOPATHIC DISEASE CHARACTERIZED BY UNEXPLAINED FATIGUE THAT FAILS TO RESOLVE WITH SUFFICIENT REST. DIAGNOSIS IS BASED ON A LIST OF SYMPTOMS AND EXCLUSION OF OTHER FATIGUE-RELATED HEALTH CONDITIONS. DESPITE A HETEROGENEOUS PATIENT POPULATION, IMMUNE AND HYPOTHALAMIC-PITUITARY-ADRENAL (HPA) AXIS FUNCTION DIFFERENCES, SUCH AS ENHANCED NEGATIVE FEEDBACK TO GLUCOCORTICOIDS, ARE RECURRING FINDINGS IN ME/CFS STUDIES. EPIGENETIC MODIFICATIONS, SUCH AS CPG METHYLATION, ARE KNOWN TO REGULATE LONG-TERM PHENOTYPIC DIFFERENCES AND PREVIOUS WORK BY OUR GROUP FOUND DNA METHYLOME DIFFERENCES IN ME/CFS, HOWEVER THE RELATIONSHIP BETWEEN DNA METHYLOME MODIFICATIONS, CLINICAL AND FUNCTIONAL CHARACTERISTICS ASSOCIATED WITH ME/CFS HAS NOT BEEN EXAMINED. METHODS: WE EXAMINED THE DNA METHYLOME IN PERIPHERAL BLOOD MONONUCLEAR CELLS (PBMCS) OF A LARGER COHORT OF FEMALE ME/CFS PATIENTS USING THE ILLUMINA HUMANMETHYLATION450 BEADCHIP ARRAY. IN PARALLEL TO THE DNA METHYLOME ANALYSIS, WE INVESTIGATED IN VITRO GLUCOCORTICOID SENSITIVITY DIFFERENCES BY STIMULATING PBMCS WITH PHYTOHAEMAGGLUTININ AND SUPPRESSED GROWTH WITH DEXAMETHASONE. WE EXPLORED DNA METHYLATION DIFFERENCES USING BISULFITE PYROSEQUENCING AND STATISTICAL PERMUTATION. LINEAR REGRESSION WAS IMPLEMENTED TO DISCOVER EPIGENOMIC REGIONS ASSOCIATED WITH SELF-REPORTED QUALITY OF LIFE AND NETWORK ANALYSIS OF GENE ONTOLOGY TERMS TO BIOLOGICALLY CONTEXTUALIZE RESULTS. RESULTS: WE DETECTED 12,608 DIFFERENTIALLY METHYLATED SITES BETWEEN ME/CFS PATIENTS AND HEALTHY CONTROLS PREDOMINANTLY LOCALIZED TO CELLULAR METABOLISM GENES, SOME OF WHICH WERE ALSO RELATED TO SELF-REPORTED QUALITY OF LIFE HEALTH SCORES. AMONG ME/CFS PATIENTS, GLUCOCORTICOID SENSITIVITY WAS ASSOCIATED WITH DIFFERENTIAL METHYLATION AT 13 LOCI. CONCLUSIONS: OUR RESULTS INDICATE DNA METHYLATION MODIFICATIONS IN CELLULAR METABOLISM IN ME/CFS DESPITE A HETEROGENEOUS PATIENT POPULATION, IMPLICATING THESE PROCESSES IN IMMUNE AND HPA AXIS DYSFUNCTION IN ME/CFS. MODIFICATIONS TO EPIGENETIC LOCI ASSOCIATED WITH DIFFERENCES IN GLUCOCORTICOID SENSITIVITY MAY BE IMPORTANT AS BIOMARKERS FOR FUTURE CLINICAL TESTING. OVERALL, THESE FINDINGS ALIGN WITH RECENT ME/CFS WORK THAT POINT TOWARDS IMPAIRMENT IN CELLULAR ENERGY PRODUCTION IN THIS PATIENT POPULATION. 2017 4 1026 48 CIRCULATING MIRNAS EXPRESSION IN MYALGIC ENCEPHALOMYELITIS/CHRONIC FATIGUE SYNDROME. MYALGIC ENCEPHALOMYELITIS/CHRONIC FATIGUE SYNDROME (ME/CFS) IS A COMPLEX MULTIFACTORIAL DISEASE THAT CAUSES INCREASING MORBIDITY WORLDWIDE, AND MANY INDIVIDUALS WITH ME/CFS SYMPTOMS REMAIN UNDIAGNOSED DUE TO THE LACK OF DIAGNOSTIC BIOMARKERS. ITS ETIOLOGY IS STILL UNKNOWN, BUT INCREASING EVIDENCE SUPPORTS A ROLE OF HERPESVIRUSES (INCLUDING HHV-6A AND HHV-6B) AS POTENTIAL TRIGGERS. INTERESTINGLY, THE INFECTION BY THESE VIRUSES HAS BEEN REPORTED TO IMPACT THE EXPRESSION OF MICRORNAS (MIRNAS), SHORT NON-CODING RNA SEQUENCES WHICH HAVE BEEN SUGGESTED TO BE EPIGENETIC FACTORS MODULATING ME/CFS PATHOGENIC MECHANISMS. NOTABLY, THE PRESENCE OF CIRCULATING MIRNAS IN PLASMA HAS RAISED THE POSSIBILITY TO USE THEM AS VALUABLE BIOMARKERS FOR DISTINGUISHING ME/CFS PATIENTS FROM HEALTHY CONTROLS. THUS, THIS STUDY AIMED AT DETERMINING THE ROLE OF EIGHT MIRNAS, WHICH WERE SELECTED FOR THEIR PREVIOUS ASSOCIATION WITH ME/CFS, AS POTENTIAL CIRCULATING BIOMARKERS OF THE DISEASE. THEIR PRESENCE WAS QUANTITATIVELY EVALUATED IN PLASMA FROM 40 ME/CFS PATIENTS AND 20 HEALTHY CONTROLS BY SPECIFIC TAQMAN ASSAYS, AND THE RESULTS SHOWED THAT SIX OUT OF THE EIGHT OF THE SELECTED MIRNAS WERE DIFFERENTLY EXPRESSED IN PATIENTS COMPARED TO CONTROLS; MORE SPECIFICALLY, FIVE MIRNAS WERE SIGNIFICANTLY UPREGULATED (MIR-127-3P, MIR-142-5P, MIR-143-3P, MIR-150-5P, AND MIR-448), AND ONE WAS DOWNMODULATED (MIR-140-5P). MIRNA LEVELS DIRECTLY CORRELATED WITH DISEASE SEVERITY, WHEREAS NO SIGNIFICANT CORRELATIONS WERE OBSERVED WITH THE PLASMA LEVELS OF SEVEN PRO-INFLAMMATORY CYTOKINES OR WITH THE PRESENCE/LOAD OF HHV-6A/6B GENOME, AS JUDGED BY SPECIFIC PCR AMPLIFICATION. THE RESULTS MAY OPEN THE WAY FOR FURTHER VALIDATION OF MIRNAS AS NEW POTENTIAL BIOMARKERS IN ME/CFS AND INCREASE THE KNOWLEDGE OF THE COMPLEX PATHWAYS INVOLVED IN THE ME/CFS DEVELOPMENT. 2023 5 3496 50 IDENTIFICATION OF MYALGIC ENCEPHALOMYELITIS/CHRONIC FATIGUE SYNDROME-ASSOCIATED DNA METHYLATION PATTERNS. BACKGROUND: MYALGIC ENCEPHALOMYELITIS/CHRONIC FATIGUE SYNDROME (ME/CFS) IS A COMPLEX CONDITION INVOLVING MULTIPLE ORGAN SYSTEMS AND CHARACTERIZED BY PERSISTENT/RELAPSING DEBILITATING FATIGUE, IMMUNE DYSFUNCTION, NEUROLOGICAL PROBLEMS, AND OTHER SYMPTOMS NOT CURABLE FOR AT LEAST 6 MONTHS. DISRUPTION OF DNA METHYLATION PATTERNS HAS BEEN TIED TO VARIOUS IMMUNE AND NEUROLOGICAL DISEASES; HOWEVER, ITS STATUS IN ME/CFS REMAINS UNCERTAIN. OUR STUDY AIMED AT IDENTIFYING CHANGES IN THE DNA METHYLATION PATTERNS THAT ASSOCIATE WITH ME/CFS. METHODS: WE EXTRACTED GENOMIC DNA FROM PERIPHERAL BLOOD MONONUCLEAR CELLS FROM 13 ME/CFS STUDY SUBJECTS AND 12 HEALTHY CONTROLS AND MEASURED GLOBAL DNA METHYLATION BY ELISA-LIKE METHOD AND SITE-SPECIFIC METHYLATION STATUS USING ILLUMINA METHYLATIONEPIC MICROARRAYS. PYROSEQUENCING VALIDATION INCLUDED 33 ME/CFS CASES AND 31 CONTROLS FROM TWO GEOGRAPHICALLY DISTANT COHORTS. RESULTS: GLOBAL DNA METHYLATION LEVELS OF ME/CFS CASES WERE SIMILAR TO THOSE OF CONTROLS. HOWEVER, MICROARRAY-BASED APPROACH ALLOWED DETECTION OF 17,296 DIFFERENTIALLY METHYLATED CPG SITES IN 6,368 GENES ACROSS REGULATORY ELEMENTS AND WITHIN CODING REGIONS OF GENES. ANALYSIS OF DNA METHYLATION IN PROMOTER REGIONS REVEALED 307 DIFFERENTIALLY METHYLATED PROMOTERS. INGENUITY PATHWAY ANALYSIS INDICATED THAT GENES ASSOCIATED WITH DIFFERENTIALLY METHYLATED PROMOTERS PARTICIPATED IN AT LEAST 15 DIFFERENT PATHWAYS MOSTLY RELATED TO CELL SIGNALING WITH A STRONG IMMUNE COMPONENT. CONCLUSIONS: THIS IS THE FIRST STUDY THAT HAS EXPLORED GENOME-WIDE EPIGENETIC CHANGES ASSOCIATED WITH ME/CFS USING THE ADVANCED ILLUMINA METHYLATIONEPIC MICROARRAYS COVERING ABOUT 850,000 CPG SITES IN TWO GEOGRAPHICALLY DISTANT COHORTS OF ME/CFS CASES AND MATCHED CONTROLS. OUR RESULTS ARE ALIGNED WITH PREVIOUS STUDIES THAT INDICATE A DYSREGULATION OF THE IMMUNE SYSTEM IN ME/CFS. THEY ALSO SUGGEST A POTENTIAL ROLE OF EPIGENETIC DE-REGULATION IN THE PATHOBIOLOGY OF ME/CFS. WE PROPOSE SCREENING OF LARGER COHORTS OF ME/CFS CASES TO DETERMINE THE EXTERNAL VALIDITY OF THESE EPIGENETIC CHANGES IN ORDER TO IMPLEMENT THEM AS POSSIBLE DIAGNOSTIC MARKERS IN CLINICAL SETTING. 2018 6 812 49 CHANGES IN DNA METHYLATION PROFILES OF MYALGIC ENCEPHALOMYELITIS/CHRONIC FATIGUE SYNDROME PATIENTS REFLECT SYSTEMIC DYSFUNCTIONS. BACKGROUND: MYALGIC ENCEPHALOMYELITIS/CHRONIC FATIGUE SYNDROME (ME/CFS) IS A LIFELONG DEBILITATING DISEASE WITH A COMPLEX PATHOLOGY NOT YET CLEARLY DEFINED. SUSCEPTIBILITY TO ME/CFS INVOLVES GENETIC PREDISPOSITION AND EXPOSURE TO ENVIRONMENTAL FACTORS, SUGGESTING AN EPIGENETIC ASSOCIATION. EPIGENETIC STUDIES WITH OTHER ME/CFS COHORTS HAVE USED ARRAY-BASED TECHNOLOGY TO IDENTIFY DIFFERENTIALLY METHYLATED INDIVIDUAL SITES. CHANGES IN RNA QUANTITIES AND PROTEIN ABUNDANCE HAVE BEEN DOCUMENTED IN OUR PREVIOUS INVESTIGATIONS WITH THE SAME ME/CFS COHORT USED FOR THIS STUDY. RESULTS: DNA FROM A WELL-CHARACTERISED NEW ZEALAND COHORT OF 10 ME/CFS PATIENTS AND 10 AGE-/SEX-MATCHED HEALTHY CONTROLS WAS ISOLATED FROM PERIPHERAL BLOOD MONONUCLEAR (PBMC) CELLS, AND USED TO GENERATE REDUCED GENOME-SCALE DNA METHYLATION MAPS USING REDUCED REPRESENTATION BISULPHITE SEQUENCING (RRBS). THE SEQUENCING DATA WERE ANALYSED UTILISING THE DMAP ANALYSIS PIPELINE TO IDENTIFY DIFFERENTIALLY METHYLATED FRAGMENTS, AND THE METHYLKIT PIPELINE WAS USED TO QUANTIFY METHYLATION DIFFERENCES AT INDIVIDUAL CPG SITES. DMAP IDENTIFIED 76 DIFFERENTIALLY METHYLATED FRAGMENTS AND METHYLKIT IDENTIFIED 394 DIFFERENTIALLY METHYLATED CYTOSINES THAT INCLUDED BOTH HYPER- AND HYPO-METHYLATION. FOUR CLUSTERS WERE IDENTIFIED WHERE DIFFERENTIALLY METHYLATED DNA FRAGMENTS OVERLAPPED WITH OR WERE WITHIN CLOSE PROXIMITY TO MULTIPLE DIFFERENTIALLY METHYLATED INDIVIDUAL CYTOSINES. THESE CLUSTERS IDENTIFIED REGULATORY REGIONS FOR 17 PROTEIN ENCODING GENES RELATED TO METABOLIC AND IMMUNE ACTIVITY. ANALYSIS OF DIFFERENTIALLY METHYLATED GENE BODIES (EXONS/INTRONS) IDENTIFIED 122 UNIQUE GENES. COMPARISON WITH OTHER STUDIES ON PBMCS FROM ME/CFS PATIENTS AND CONTROLS WITH ARRAY TECHNOLOGY SHOWED 59% OF THE GENES IDENTIFIED IN THIS STUDY WERE ALSO FOUND IN ONE OR MORE OF THESE STUDIES. FUNCTIONAL PATHWAY ENRICHMENT ANALYSIS IDENTIFIED 30 ASSOCIATED PATHWAYS. THESE INCLUDED IMMUNE, METABOLIC AND NEUROLOGICAL-RELATED FUNCTIONS DIFFERENTIALLY REGULATED IN ME/CFS PATIENTS COMPARED TO THE MATCHED HEALTHY CONTROLS. CONCLUSIONS: MAJOR DIFFERENCES WERE IDENTIFIED IN THE DNA METHYLATION PATTERNS OF ME/CFS PATIENTS THAT CLEARLY DISTINGUISHED THEM FROM THE HEALTHY CONTROLS. OVER HALF FOUND IN GENE BODIES WITH RRBS IN THIS STUDY HAD BEEN IDENTIFIED IN OTHER ME/CFS STUDIES USING THE SAME CELLS BUT WITH ARRAY TECHNOLOGY. WITHIN THE ENRICHED FUNCTIONAL IMMUNE, METABOLIC AND NEUROLOGICAL PATHWAYS, A NUMBER OF ENRICHED NEUROTRANSMITTER AND NEUROPEPTIDE REACTOME PATHWAYS HIGHLIGHTED A DISTURBED NEUROLOGICAL PATHOPHYSIOLOGY WITHIN THE PATIENT GROUP. 2020 7 2050 37 EPIGENETIC COMPONENTS OF MYALGIC ENCEPHALOMYELITIS/CHRONIC FATIGUE SYNDROME UNCOVER POTENTIAL TRANSPOSABLE ELEMENT ACTIVATION. PURPOSE: STUDIES TO DETERMINE EPIGENETIC CHANGES ASSOCIATED WITH MYALGIC ENCEPHALOMYELITIS/CHRONIC FATIGUE SYNDROME (ME/CFS) REMAIN SCARCE; HOWEVER, CURRENT EVIDENCE CLEARLY SHOWS THAT METHYLATION PATTERNS OF GENOMIC DNA AND NONCODING RNA PROFILES OF IMMUNE CELLS DIFFER BETWEEN PATIENTS AND HEALTHY SUBJECTS, SUGGESTING AN ACTIVE ROLE OF THESE EPIGENETIC MECHANISMS IN THE DISEASE. THE PRESENT STUDY COMPARES AND CONTRASTS THE AVAILABLE ME/CFS EPIGENETIC DATA IN AN EFFORT TO EVIDENCE OVERLAPPING PATHWAYS CAPABLE OF EXPLAINING AT LEAST SOME OF THE DYSFUNCTIONAL IMMUNE PARAMETERS LINKED TO THIS DISEASE. METHODS: A SYSTEMATIC SEARCH OF THE LITERATURE EVALUATING THE ME/CFS EPIGENOME LANDSCAPE WAS PERFORMED FOLLOWING THE PREFERRED REPORTING ITEMS FOR SYSTEMATIC REVIEWS AND META-ANALYSES CRITERIA. DIFFERENTIAL DNA METHYLATION AND NONCODING RNA DIFFERENTIAL EXPRESSION PATTERNS ASSOCIATED WITH ME/CFS WERE USED TO SCREEN FOR THE PRESENCE OF TRANSPOSABLE ELEMENTS USING THE DFAM BROWSER, A SEARCH PROGRAM NURTURED WITH THE REPBASE REPETITIVE SEQUENCE DATABASE AND THE REPEATMASKER ANNOTATION TOOL. FINDINGS: UNEXPECTEDLY, PARTICULAR ASSOCIATIONS OF TRANSPOSABLE ELEMENTS AND ME/CFS EPIGENETIC HALLMARKS WERE UNCOVERED. A MODEL FOR THE DISEASE EMERGED INVOLVING TRANSCRIPTIONAL INDUCTION OF ENDOGENOUS DORMANT TRANSPOSONS AND STRUCTURED CELLULAR RNA INTERACTIONS, TRIGGERING THE ACTIVATION OF THE INNATE IMMUNE SYSTEM WITHOUT A CONCOMITANT ACTIVE INFECTION. IMPLICATIONS: REPETITIVE SEQUENCE FILTERS (IE, REPEATMASKER) SHOULD BE AVOIDED WHEN ANALYZING TRANSCRIPTOMIC DATA TO ASSESS THE POTENTIAL PARTICIPATION OF REPETITIVE SEQUENCES ("JUNK REPETITIVE DNA"), REPRESENTING >45% OF THE HUMAN GENOME, IN THE ONSET AND EVOLUTION OF ME/CFS. IN ADDITION, TRANSPOSABLE ELEMENT SCREENINGS AIMED AT DESIGNING COST-EFFECTIVE, FOCUSED EMPIRICAL ASSAYS THAT CAN CONFIRM OR DISPROVE THE SUSPECTED INVOLVEMENT OF TRANSPOSON TRANSCRIPTIONAL ACTIVATION IN THIS DISEASE, FOLLOWING THE PILOT STRATEGY PRESENTED HERE, WILL REQUIRE DATABASES GATHERING LARGE ME/CFS EPIGENETIC DATASETS. 2019 8 1699 35 DYNAMIC EPIGENETIC CHANGES DURING A RELAPSE AND RECOVERY CYCLE IN MYALGIC ENCEPHALOMYELITIS/CHRONIC FATIGUE SYNDROME. MYALGIC ENCEPHALOMYELITIS/CHRONIC FATIGUE SYNDROME (ME/CFS) IS A COMPLEX DISEASE WITH VARIABLE SEVERITY. PATIENTS EXPERIENCE FREQUENT RELAPSES WHERE SYMPTOMS INCREASE IN SEVERITY, LEAVING THEM WITH A MARKED REDUCTION IN QUALITY OF LIFE. PREVIOUS WORK HAS INVESTIGATED MOLECULAR DIFFERENCES BETWEEN ME/CFS PATIENTS AND HEALTHY CONTROLS, BUT NOT THE DYNAMIC CHANGES SPECIFIC TO EACH INDIVIDUAL PATIENT. WE APPLIED PRECISION MEDICINE HERE TO MAP GENOMIC CHANGES IN TWO SELECTED ME/CFS PATIENTS THROUGH A PERIOD THAT CONTAINED A RELAPSE RECOVERY CYCLE. DNA WAS ISOLATED FROM TWO PATIENTS AND A HEALTHY AGE/GENDER MATCHED CONTROL AT REGULAR INTERVALS AND CAPTURED THE PATIENT RELAPSE IN EACH CASE. REDUCED REPRESENTATION DNA METHYLATION SEQUENCING PROFILES WERE OBTAINED SPANNING THE RELAPSE RECOVERY CYCLE. BOTH PATIENTS SHOWED A SIGNIFICANTLY LARGER METHYLOME VARIABILITY (10-20-FOLD) THROUGH THE PERIOD OF SAMPLING COMPARED WITH THE CONTROL. DURING THE RELAPSE, CHANGES IN THE METHYLOME PROFILES OF THE TWO PATIENTS WERE DETECTED IN REGULATORY-ACTIVE REGIONS OF THE GENOME THAT WERE ASSOCIATED, RESPECTIVELY, WITH 157 AND 127 DOWNSTREAM GENES, INDICATING DISTURBED METABOLIC, IMMUNE AND INFLAMMATORY FUNCTIONS. SEVERE HEALTH RELAPSES IN THE ME/CFS PATIENTS RESULTED IN FUNCTIONALLY IMPORTANT CHANGES IN THEIR DNA METHYLOMES THAT, WHILE DIFFERING BETWEEN THE TWO PATIENTS, LED TO VERY SIMILAR COMPROMISED PHYSIOLOGY. DNA METHYLATION AS A SIGNATURE OF DISEASE VARIABILITY IN ONGOING ME/CFS MAY HAVE PRACTICAL APPLICATIONS FOR STRATEGIES TO DECREASE RELAPSE FREQUENCY. 2022 9 639 43 BIOMARKERS FOR MYALGIC ENCEPHALOMYELITIS/CHRONIC FATIGUE SYNDROME (ME/CFS): A SYSTEMATIC REVIEW. BACKGROUND: MYALGIC ENCEPHALOMYELITIS/CHRONIC FATIGUE SYNDROME (ME/CFS) IS A MULTIFACETED CONDITION THAT AFFECTS MOST BODY SYSTEMS. THERE IS CURRENTLY NO KNOWN DIAGNOSTIC BIOMARKER; INSTEAD, DIAGNOSIS IS DEPENDENT ON APPLICATION OF SYMPTOM-BASED CASE CRITERIA FOLLOWING EXCLUSION OF ANY OTHER POTENTIAL MEDICAL CONDITIONS. WHILE THERE ARE SOME STUDIES THAT REPORT POTENTIAL BIOMARKERS FOR ME/CFS, THEIR EFFICACY HAS NOT BEEN VALIDATED. THE AIM OF THIS SYSTEMATIC REVIEW IS TO COLLATE AND APPRAISE LITERATURE PERTAINING TO A POTENTIAL BIOMARKER(S) WHICH MAY EFFECTIVELY DIFFERENTIATE ME/CFS PATIENTS FROM HEALTHY CONTROLS. METHODS: THIS SYSTEMATIC REVIEW WAS CONDUCTED ACCORDING TO THE PREFERRED REPORTING ITEMS FOR SYSTEMATIC REVIEWS AND META-ANALYSES AND COCHRANE REVIEW GUIDELINES. PUBMED, EMBASE AND SCOPUS WERE SYSTEMATICALLY SEARCHED FOR ARTICLES CONTAINING "BIOMARKER" AND "ME/CFS" KEYWORDS IN THE ABSTRACT OR TITLE AND IF THEY INCLUDED THE FOLLOWING CRITERIA: (1) WERE OBSERVATIONAL STUDIES PUBLISHED BETWEEN DECEMBER 1994 AND APRIL 2022; (2) INVOLVED ADULT HUMAN PARTICIPANTS; (3) FULL TEXT IS AVAILABLE IN ENGLISH (4) ORIGINAL RESEARCH; (5) DIAGNOSIS OF ME/CFS PATIENTS MADE ACCORDING TO THE FUKUDA CRITERIA (1994), CANADIAN CONSENSUS CRITERIA (2003), INTERNATIONAL CONSENSUS CRITERIA (2011) OR INSTITUTE OF MEDICINE CRITERIA (2015); (6) STUDY INVESTIGATED POTENTIAL BIOMARKERS OF ME/CFS COMPARED TO HEALTHY CONTROLS. QUALITY AND BIAS WERE ASSESSED USING THE JOANNA BRIGGS INSTITUTE CRITICAL APPRAISAL CHECKLIST FOR CASE CONTROL STUDIES. RESULTS: A TOTAL OF 101 PUBLICATIONS WERE INCLUDED IN THIS SYSTEMATIC REVIEW. POTENTIAL BIOMARKERS RANGED FROM GENETIC/EPIGENETIC (19.8%), IMMUNOLOGICAL (29.7%), METABOLOMICS/MITOCHONDRIAL/MICROBIOME (14.85%), ENDOVASCULAR/CIRCULATORY (17.82%), NEUROLOGICAL (7.92%), ION CHANNEL (8.91%) AND PHYSICAL DYSFUNCTION BIOMARKERS (8.91%). MOST OF THE POTENTIAL BIOMARKERS REPORTED WERE BLOOD-BASED (79.2%). USE OF LYMPHOCYTES AS A MODEL TO INVESTIGATE ME/CFS PATHOLOGY WAS PROMINENT AMONG IMMUNE-BASED BIOMARKERS. MOST BIOMARKERS HAD SECONDARY (43.56%) OR TERTIARY (54.47%) SELECTIVITY, WHICH IS THE ABILITY FOR THE BIOMARKER TO IDENTIFY A DISEASE-CAUSING AGENT, AND A MODERATE (59.40%) TO COMPLEX (39.60%) EASE-OF-DETECTION, INCLUDING THE REQUIREMENT OF SPECIALISED EQUIPMENT. CONCLUSIONS: ALL POTENTIAL ME/CFS BIOMARKERS DIFFERED IN EFFICIENCY, QUALITY, AND TRANSLATABILITY AS A DIAGNOSTIC MARKER. REPRODUCIBILITY OF FINDINGS BETWEEN THE INCLUDED PUBLICATIONS WERE LIMITED, HOWEVER, SEVERAL STUDIES VALIDATED THE INVOLVEMENT OF IMMUNE DYSFUNCTION IN THE PATHOLOGY OF ME/CFS AND THE USE OF LYMPHOCYTES AS A MODEL TO INVESTIGATE THE PATHOMECHANISM OF ILLNESS. THE HETEROGENEITY SHOWN ACROSS MANY OF THE INCLUDED STUDIES HIGHLIGHTS THE NEED FOR MULTIDISCIPLINARY RESEARCH AND UNIFORM PROTOCOLS IN ME/CFS BIOMARKER RESEARCH. 2023 10 950 27 CHRONIC MILD STRESS EXACERBATES SEVERITY OF EXPERIMENTAL AUTOIMMUNE ENCEPHALOMYELITIS IN ASSOCIATION WITH ALTERED NON-CODING RNA AND METABOLIC BIOMARKERS. THE CAUSAL FACTORS DETERMINING THE ONSET AND SEVERITY OF MULTIPLE SCLEROSIS (MS) ARE NOT WELL UNDERSTOOD. HERE, WE INVESTIGATED THE INFLUENCE OF CHRONIC STRESS ON CLINICAL SYMPTOMS, METABOLIC AND EPIGENETIC MANIFESTATIONS OF EXPERIMENTAL AUTOIMMUNE ENCEPHALOMYELITIS (EAE), A COMMON ANIMAL MODEL OF MS. LEWIS RATS WERE IMMUNIZED FOR MONOPHASIC EAE WITH MBP(69-88) AND WERE EXPOSED TO CHRONIC STRESS FOR 37DAYS STARTING 7DAYS PRIOR TO IMMUNIZATION. THE EXPOSURE TO STRESS ACCELERATED AND EXACERBATED THE CLINICAL SYMPTOMS OF EAE. BOTH STRESS AND EAE ALSO DISRUPTED METABOLIC STATUS AS INDICATED BY TRACE ELEMENTAL ANALYSIS IN BODY HAIR. STRESS PARTICULARLY EXACERBATED CHLORINE DEPOSITION IN EAE ANIMALS. MOREOVER, DEEP SEQUENCING REVEALED A CONSIDERABLE IMPACT OF STRESS ON MICRORNA EXPRESSION IN EAE. EAE BY ITSELF UPREGULATED MICRORNA EXPRESSION IN LUMBAR SPINAL CORD, INCLUDING MIR-21, MIR-142-3P, MIR-142-5P, MIR-146A, AND MIR-155. STRESS IN EAE FURTHER UP-REGULATED MIR-16, MIR-146A AND MIR-155 LEVELS. THE LATTER TWO MICRORNAS ARE RECOGNIZED BIOMARKERS OF HUMAN MS. THUS, STRESS MAY SYNERGISTICALLY EXACERBATE SEVERITY OF EAE BY ALTERING EPIGENETIC REGULATORY PATHWAYS. THE FINDINGS SUGGEST THAT STRESS MAY REPRESENT A SIGNIFICANT RISK FACTOR FOR SYMPTOMATIC DETERIORATION IN MS. STRESS-RELATED METABOLIC AND MICRORNA SIGNATURES SUPPORT THEIR VALUE AS BIOMARKERS FOR PREDICTING THE RISK AND SEVERITY OF MS. 2017 11 488 49 ASSESSING DIAGNOSTIC VALUE OF MICRORNAS FROM PERIPHERAL BLOOD MONONUCLEAR CELLS AND EXTRACELLULAR VESICLES IN MYALGIC ENCEPHALOMYELITIS/CHRONIC FATIGUE SYNDROME. MYALGIC ENCEPHALOMYELITIS/CHRONIC FATIGUE SYNDROME (ME/CFS) IS A DEBILITATING MULTISYSTEMIC DISEASE OF UNKNOWN ETIOLOGY, AFFECTING THOUSANDS OF INDIVIDUALS WORLDWIDE. ITS DIAGNOSIS STILL RELIES ON RULING OUT MEDICAL PROBLEMS LEADING TO UNEXPLAINED FATIGUE DUE TO A COMPLETE LACK OF DISEASE-SPECIFIC BIOMARKERS. OUR GROUP AND OTHERS HAVE EXPLORED THE POTENTIAL VALUE OF MICRORNA PROFILES (MIRNOMES) AS DIAGNOSTIC TOOLS FOR THIS DISEASE. HOWEVER, HETEROGENEITY OF PARTICIPANTS, LOW NUMBERS, THE VARIETY OF SAMPLES ASSAYED, AND OTHER PRE-ANALYTICAL VARIABLES, HAVE HAMPERED THE IDENTIFICATION OF DISEASE-ASSOCIATED MIRNOMES. IN THIS STUDY, OUR TEAM HAS EVALUATED, FOR THE FIRST TIME, ME/CFS MIRNOMES IN PERIPHERAL BLOOD MONONUCLEAR CELLS (PBMCS) AND EXTRACELLULAR VESICLES (EVS) FROM SEVERELY ILL PATIENTS RECRUITED AT THE MONOGRAPHIC UK ME BIOBANK TO ASSESS, USING STANDARD OPERATING PROCEDURES (SOPS), BLOOD FRACTIONS WITH OPTIMAL DIAGNOSTIC POWER FOR A RAPID TRANSLATION OF A MIR-BASED DIAGNOSTIC METHOD INTO THE CLINIC. OUR RESULTS SHOW THAT ROUTINE CREATINE KINASE (CK) BLOOD VALUES, PLASMA EVS PHYSICAL CHARACTERISTICS (INCLUDING COUNTS, SIZE AND ZETA-POTENTIAL), AND A LIMITED NUMBER OF DIFFERENTIALLY EXPRESSED PBMC AND EV MIRNAS APPEAR SIGNIFICANTLY ASSOCIATED WITH SEVERE ME/CFS (P < 0.05). GENE ENRICHMENT ANALYSIS POINTS TO EPIGENETIC AND NEUROIMMUNE DYSREGULATED PATHWAYS, IN AGREEMENT WITH PREVIOUS REPORTS. POPULATION VALIDATION BY A COST-EFFECTIVE APPROACH LIMITED TO THESE FEW POTENTIALLY DISCRIMINATING VARIABLES IS GRANTED. 2020 12 41 27 A COMPARISON OF NEUROIMAGING ABNORMALITIES IN MULTIPLE SCLEROSIS, MAJOR DEPRESSION AND CHRONIC FATIGUE SYNDROME (MYALGIC ENCEPHALOMYELITIS): IS THERE A COMMON CAUSE? THERE IS COPIOUS EVIDENCE OF ABNORMALITIES IN RESTING-STATE FUNCTIONAL NETWORK CONNECTIVITY STATES, GREY AND WHITE MATTER PATHOLOGY AND IMPAIRED CEREBRAL PERFUSION IN PATIENTS AFFORDED A DIAGNOSIS OF MULTIPLE SCLEROSIS, MAJOR DEPRESSION OR CHRONIC FATIGUE SYNDROME (CFS) (MYALGIC ENCEPHALOMYELITIS). SYSTEMIC INFLAMMATION MAY WELL BE A MAJOR ELEMENT EXPLAINING SUCH FINDINGS. INTER-PATIENT AND INTER-ILLNESS VARIATIONS IN NEUROIMAGING FINDINGS MAY ARISE AT LEAST IN PART FROM REGIONAL GENETIC, EPIGENETIC AND ENVIRONMENTAL VARIATIONS IN THE FUNCTIONS OF MICROGLIA AND ASTROCYTES. REGIONAL DIFFERENCES IN NEURONAL RESISTANCE TO OXIDATIVE AND INFLAMMATORY INSULTS AND IN THE PERFORMANCE OF ANTIOXIDANT DEFENCES IN THE CENTRAL NERVOUS SYSTEM MAY ALSO PLAY A ROLE. IMPORTANTLY, REPLICATED EXPERIMENTAL FINDINGS SUGGEST THAT THE USE OF HIGH-RESOLUTION SPECT IMAGING MAY HAVE THE CAPACITY TO DIFFERENTIATE PATIENTS AFFORDED A DIAGNOSIS OF CFS FROM THOSE WITH A DIAGNOSIS OF DEPRESSION. FURTHER RESEARCH INVOLVING THIS FORM OF NEUROIMAGING APPEARS WARRANTED IN AN ATTEMPT TO OVERCOME THE PROBLEM OF AETIOLOGICALLY HETEROGENEOUS COHORTS WHICH PROBABLY EXPLAIN CONFLICTING FINDINGS PRODUCED BY INVESTIGATIVE TEAMS ACTIVE IN THIS FIELD. HOWEVER, THE IONISING RADIATION AND RELATIVE LACK OF SENSITIVITY INVOLVED PROBABLY PRECLUDE ITS USE AS A ROUTINE DIAGNOSTIC TOOL. 2018 13 5426 35 REGULATION OF SIRTUIN EXPRESSION IN AUTOIMMUNE NEUROINFLAMMATION: INDUCTION OF SIRT1 IN OLIGODENDROCYTE PROGENITOR CELLS. IN MULTIPLE SCLEROSIS (MS) REGENERATION OF OLIGODENDROCYTES FOLLOWING INFLAMMATORY DEMYELINATION IS LIMITED BY THE COMPROMISED ABILITY OF PROGENITORS TO REPOPULATE LESIONED AREAS AND TRANSITION TO FUNCTIONALLY COMPETENT OLIGODENDROCYTES. REGARDING UNDERLYING MECHANISMS, THE INVOLVEMENT OF EPIGENETIC PROCESSES HAS BEEN SUGGESTED, E.G. THE CONTRIBUTION OF HISTONE DEACETYLASES (HDAC) KNOWN TO REGULATE OLIGODENDROCYTE PROGENITOR CELL (OPC) DIFFERENTIATION. HOWEVER, THEIR PRECISE EXPRESSION PATTERNS, PARTICULAR OF REDOX-SENSITIVE NAD(+) HDACS, REMAINS LARGELY UNKNOWN. IN THIS STUDY, WE DETERMINED THE EXPRESSION AND ACTIVITY OF SIRTUINS, MEMBERS OF THE HDAC CLASS III FAMILY WITH A SPECIFIC FOCUS ON SIRT1, PREVIOUSLY ASSOCIATED WITH NEURODEGENERATIVE, INFLAMMATORY AND DEMYELINATING DISORDERS OF THE CENTRAL NERVOUS SYSTEM (CNS). BY INVESTIGATING MOUSE EXPERIMENTAL AUTOIMMUNE ENCEPHALOMYELITIS (EAE), A MODEL FOR MS, WE FOUND THAT TRANSCRIPTION OF SIRT1, SIRT2 AND SIRT6 WAS SIGNIFICANTLY INCREASED IN THE CNS DURING CHRONIC DISEASE STAGES. WE CONFIRMED THIS FINDING FOR SIRT1 PROTEIN EXPRESSION AND WERE ABLE TO LOCALIZE UPREGULATED SIRT1 IN NUCLEI OF NG2(+) OR PDGFRALPHA(+) OPCS IN DEMYELINATED BRAIN LESIONS. IN CULTURED MOUSE A2B5(+) OPCS BLOCKADE OF SIRT1 ACTIVITY BY THE SMALL MOLECULE COMPOUND EX527 ENHANCED MITOTIC ACTIVITY BUT DID NOT AFFECT THE CAPACITY TO DIFFERENTIATE. A SIMILAR PATTERN WAS DETECTABLE IN OPCS DERIVED FROM SIRT1-DEFICIENT ANIMALS. TAKEN TOGETHER, OUR DATA SUGGEST THAT SIRT1 INHIBITION MAY HELP TO EXPAND THE ENDOGENOUS POOL OF OPCS WITHOUT AFFECTING THEIR DIFFERENTIATION. 2019 14 4304 34 MICRORNA-223 PROTECTS NEURONS FROM DEGENERATION IN EXPERIMENTAL AUTOIMMUNE ENCEPHALOMYELITIS. MULTIPLE SCLEROSIS IS A CHRONIC INFLAMMATORY, DEMYELINATING, AND NEURODEGENERATIVE DISEASE AFFECTING THE BRAIN, SPINAL CORD AND OPTIC NERVES. NEURONAL DAMAGE IS TRIGGERED BY VARIOUS HARMFUL FACTORS THAT ENGAGE DIVERSE SIGNALLING CASCADES IN NEURONS; THUS, THERAPEUTIC APPROACHES TO PROTECT NEURONS WILL NEED TO FOCUS ON AGENTS THAT CAN TARGET MULTIPLE BIOLOGICAL PROCESSES. WE HAVE THEREFORE FOCUSED OUR ATTENTION ON MICRORNAS: SMALL NON-CODING RNAS THAT PRIMARILY FUNCTION AS POST-TRANSCRIPTIONAL REGULATORS THAT TARGET MESSENGER RNAS AND REPRESS THEIR TRANSLATION INTO PROTEINS. A SINGLE MICRORNA CAN TARGET MANY FUNCTIONALLY RELATED MESSENGER RNAS MAKING MICRORNAS POWERFUL EPIGENETIC REGULATORS. DYSREGULATION OF MICRORNAS HAS BEEN DESCRIBED IN MANY NEURODEGENERATIVE DISEASES INCLUDING MULTIPLE SCLEROSIS. HERE, WE REPORT THAT TWO MICRORNAS, MIR-223-3P AND MIR-27A-3P, ARE UPREGULATED IN NEURONS IN THE EXPERIMENTAL AUTOIMMUNE ENCEPHALOMYELITIS MOUSE MODEL OF CNS INFLAMMATION AND IN GREY MATTER-CONTAINING MULTIPLE SCLEROSIS LESIONS. PRIOR WORK HAS SHOWN PERIPHERAL BLOOD MONONUCLEAR CELL CONDITIONED MEDIA CAUSES SUBLETHAL DEGENERATION OF NEURONS IN CULTURE. WE FIND OVEREXPRESSION OF MIR-27A-3P OR MIR-223-3P PROTECTS DISSOCIATED CORTICAL NEURONS FROM CONDITION MEDIA MEDIATED DEGENERATION. INTRODUCTION OF MIR-223-3P IN VIVO IN MOUSE RETINAL GANGLION CELLS PROTECTS THEIR AXONS FROM DEGENERATION IN EXPERIMENTAL AUTOIMMUNE ENCEPHALOMYELITIS. IN SILICO ANALYSIS REVEALED THAT MESSENGER RNAS INVOLVED IN GLUTAMATE RECEPTOR SIGNALLING ARE ENRICHED AS MIR-27A-3P AND MIR-223-3P TARGETS. WE OBSERVE THAT ANTAGONISM OF NMDA AND AMPA TYPE GLUTAMATE RECEPTORS PROTECTS NEURONS FROM CONDITION MEDIA DEPENDENT DEGENERATION. OUR RESULTS SUGGEST THAT MIR-223-3P AND MIR-27A-3P ARE UPREGULATED IN RESPONSE TO INFLAMMATION TO MEDIATE A COMPENSATORY NEUROPROTECTIVE GENE EXPRESSION PROGRAM THAT DESENSITIZES NEURONS TO GLUTAMATE BY TARGETING MESSENGER RNAS INVOLVED IN GLUTAMATE RECEPTOR SIGNALLING. 2019 15 5591 33 ROLE OF THE EPIGENETIC FACTOR SIRT7 IN NEUROINFLAMMATION AND NEUROGENESIS. EPIGENETIC REGULATORS ARE INCREASINGLY RECOGNIZED AS RELEVANT MODULATORS IN THE IMMUNE AND NERVOUS SYSTEM. THE CLASS OF SIRTUINS CONSISTS OF NAD(+)-DEPENDENT HISTONE DEACETYLASES THAT REGULATE TRANSCRIPTION. SIRTUIN FAMILY MEMBER SIRT1 HAS ALREADY BEEN SHOWN TO INFLUENCE THE DISEASE COURSE IN AN ANIMAL MODEL OF AUTOIMMUNE NEUROINFLAMMATION (EXPERIMENTAL AUTOIMMUNE ENCEPHALOMYELITIS (EAE). A ROLE OF SIRT7, A RELATED EPIGENETIC REGULATOR, ON IMMUNE SYSTEM REGULATION HAS BEEN PROPOSED BEFORE, AS THESE MICE ARE MORE SUSCEPTIBLE TO DEVELOP INFLAMMATORY CARDIOMYOPATHY. SIRT7(-/-) ANIMALS SHOWED NO DIFFERENCES IN CLINICAL SCORE COMPARED TO WILD-TYPE LITTERMATES AFTER EAE INDUCTION WITH MYELIN OLIGODENDROCYTE GLYCOPROTEIN (MOG) PEPTIDE (35-55), ALTHOUGH WE FOUND SUBTLE IMMUNE ALTERATIONS AT DIFFERENT PHASES OF EAE AND DECREASED SURVIVAL OF NEWLY GENERATED NEURONS IN THE HIPPOCAMPUS. OUR DATA INDICATE THAT SIRT7 HAS A SLIGHT PROTECTIVE IMPACT ON BOTH THE ADAPTIVE IMMUNE SYSTEM AND NEUROGENESIS. HOWEVER, OVERALL THIS EPIGENETIC FACTOR IS NOT CAPABLE OF IMPACTING THE ACUTE OR CHRONIC PHASE OF NEUROINFLAMMATION. 2018 16 4590 29 NANOPORE SEQUENCING IDENTIFIES DIFFERENTIALLY METHYLATED GENES IN THE CENTRAL NERVOUS SYSTEM IN EXPERIMENTAL AUTOIMMUNE ENCEPHALOMYELITIS. MULTIPLE SCLEROSIS (MS) IS A CHRONIC AUTOIMMUNE-MEDIATED DEMYELINATING DISEASE OF THE CENTRAL NERVOUS SYSTEM (CNS) THAT MIGHT BE TRIGGERED BY ABERRANT EPIGENETIC CHANGES IN THE GENOME. DNA METHYLATION IS THE MOST STUDIED EPIGENETIC MECHANISM THAT PARTICIPATES IN MS PATHOGENESIS. HOWEVER, THE OVERALL METHYLATION LEVEL IN THE CNS OF MS PATIENTS REMAINS ELUSIVE. WE USED DIRECT LONG-READ NANOPORE DNA SEQUENCING AND CHARACTERIZED THE DIFFERENTIALLY METHYLATED GENES IN THE BRAIN FROM MICE WITH EXPERIMENTAL AUTOIMMUNE ENCEPHALOMYELITIS (EAE), AN ANIMAL MODEL OF MS. WE IDENTIFIED 163 HYPOMETHYLATED PROMOTERS AND 327 HYPERMETHYLATED PROMOTERS. THESE GENOMIC ALTERATIONS WERE LINKED TO VARIOUS BIOLOGICAL PROCESSES INCLUDING METABOLISM, IMMUNE RESPONSES, NEURAL ACTIVITIES, AND MITOCHONDRIAL DYNAMICS, ALL OF WHICH ARE VITAL FOR EAE DEVELOPMENT. OUR RESULTS INDICATE A GREAT POTENTIAL OF NANOPORE SEQUENCING IN IDENTIFYING GENOMIC DNA METHYLATION IN EAE AND PROVIDE IMPORTANT GUIDANCE FOR FUTURE STUDIES INVESTIGATING THE MS/EAE PATHOLOGY. 2023 17 1556 54 DNA METHYLATION MODIFICATIONS ASSOCIATED WITH CHRONIC FATIGUE SYNDROME. CHRONIC FATIGUE SYNDROME (CFS), ALSO KNOWN AS MYALGIC ENCEPHALOMYELITIS, IS A COMPLEX MULTIFACTORIAL DISEASE THAT IS CHARACTERIZED BY THE PERSISTENT PRESENCE OF FATIGUE AND OTHER PARTICULAR SYMPTOMS FOR A MINIMUM OF 6 MONTHS. SYMPTOMS FAIL TO DISSIPATE AFTER SUFFICIENT REST AND HAVE MAJOR EFFECTS ON THE DAILY FUNCTIONING OF CFS SUFFERERS. CFS IS A MULTI-SYSTEM DISEASE WITH A HETEROGENEOUS PATIENT POPULATION SHOWING A WIDE VARIETY OF FUNCTIONAL DISABILITIES AND ITS BIOLOGICAL BASIS REMAINS POORLY UNDERSTOOD. STABLE ALTERATIONS IN GENE FUNCTION IN THE IMMUNE SYSTEM HAVE BEEN REPORTED IN SEVERAL STUDIES OF CFS. EPIGENETIC MODIFICATIONS HAVE BEEN IMPLICATED IN LONG-TERM EFFECTS ON GENE FUNCTION, HOWEVER, TO OUR KNOWLEDGE, GENOME-WIDE EPIGENETIC MODIFICATIONS ASSOCIATED WITH CFS HAVE NOT BEEN EXPLORED. WE EXAMINED THE DNA METHYLOME IN PERIPHERAL BLOOD MONONUCLEAR CELLS ISOLATED FROM CFS PATIENTS AND HEALTHY CONTROLS USING THE ILLUMINA HUMANMETHYLATION450 BEADCHIP ARRAY, CONTROLLING FOR INVARIANT PROBES AND PROBES OVERLAPPING POLYMORPHIC SEQUENCES. GENE ONTOLOGY (GO) AND NETWORK ANALYSIS OF DIFFERENTIALLY METHYLATED GENES WAS PERFORMED TO DETERMINE POTENTIAL BIOLOGICAL PATHWAYS SHOWING CHANGES IN DNA METHYLATION IN CFS. WE FOUND AN INCREASED ABUNDANCE OF DIFFERENTIALLY METHYLATED GENES RELATED TO THE IMMUNE RESPONSE, CELLULAR METABOLISM, AND KINASE ACTIVITY. GENES ASSOCIATED WITH IMMUNE CELL REGULATION, THE LARGEST COORDINATED ENRICHMENT OF DIFFERENTIALLY METHYLATED PATHWAYS, SHOWED HYPOMETHYLATION WITHIN PROMOTERS AND OTHER GENE REGULATORY ELEMENTS IN CFS. THESE DATA ARE CONSISTENT WITH EVIDENCE OF MULTISYSTEM DYSREGULATION IN CFS AND IMPLICATE THE INVOLVEMENT OF DNA MODIFICATIONS IN CFS PATHOLOGY. 2014 18 6117 33 THE EPIGENETIC DRUG TRICHOSTATIN A AMELIORATES EXPERIMENTAL AUTOIMMUNE ENCEPHALOMYELITIS VIA T CELL TOLERANCE INDUCTION AND IMPAIRED INFLUX OF T CELLS INTO THE SPINAL CORD. MULTIPLE SCLEROSIS IS A T CELL MEDIATED CHRONIC DEMYELINATING DISEASE OF THE CENTRAL NERVOUS SYSTEM. ALTHOUGH CURRENTLY AVAILABLE THERAPIES REDUCE RELAPSES, THEY DO NOT FACILITATE TOLERIZATION OF MYELIN ANTIGEN-SPECIFIC T LYMPHOCYTES TO ENSURE PROLONGED PROTECTION AGAINST MULTIPLE SCLEROSIS. HERE, WE SHOW THAT TREATMENT OF NOD MICE WITH THE HISTONE DEACETYLASE INHIBITOR, TRICHOSTATIN A AFFORDS ROBUST PROTECTION AGAINST MYELIN PEPTIDE INDUCED EXPERIMENTAL AUTOIMMUNE ENCEPHALOMYELITIS, A MOUSE MODEL OF MULTIPLE SCLEROSIS. PROTECTION WAS ACCOMPANIED BY HISTONE HYPERACETYLATION, AND REDUCED INFLAMMATION AND AXONAL DAMAGE IN THE SPINAL CORD. DRUG TREATMENT DIMINISHED THE GENERATION OF CD4(+) MEMORY T CELLS AND INDUCED TOLERANCE IN CD4(+) T CELLS RECOGNIZING THE IMMUNIZING MYELIN PEPTIDE. DURING THE EARLY IMMUNIZATION PERIOD, CD4(+) T CELLS PRODUCING GM-CSF+IFN-GAMMA, GM-CSF+IL-17A, AS WELL AS THOSE EXPRESSING BOTH IL-17A+IFN-GAMMA (DOUBLE-PRODUCERS) WERE DETECTED IN THE SECONDARY LYMPHOID ORGANS FOLLOWED BY THE APPEARANCE OF CELLS PRODUCING IFN-GAMMA AND GM-CSF. ON THE OTHER HAND, IFN-GAMMA PRODUCING TH1 CELLS APPEAR FIRST IN THE SPINAL CORD FOLLOWED BY CELLS PRODUCING IL-17A AND GM-CSF. TREATMENT WITH TRICHOSTATIN A SUBSTANTIALLY REDUCED THE FREQUENCIES OF ALL T CELLS SECRETING VARIOUS LYMPHOKINES BOTH IN THE PERIPHERY AND IN THE SPINAL CORD. THESE DATA INDICATE THAT EPIGENETIC MODIFICATIONS INDUCED BY HISTONE HYPERACETYLATION FACILITATES T CELL TOLERANCE INDUCTION IN THE PERIPHERY LEADING TO REDUCED MIGRATION OF T CELLS TO THE SPINAL CORD AND MITIGATION OF NEURONAL DAMAGE AND IMPROVED CLINICAL OUTCOME. THESE RESULTS SUGGEST THAT EPIGENETIC MODULATION OF THE GENOME MAY SIMILARLY OFFER BENEFITS TO MULTIPLE SCLEROSIS PATIENTS VIA ABROGATING THE FUNCTION OF ENCEPHALITOGENIC T LYMPHOCYTES WITHOUT EXERTING SEVERE SIDE EFFECTS ASSOCIATED WITH CURRENTLY USED DISEASE-MODIFYING THERAPIES. 2017 19 6405 48 THE SARS-COV-2 RECEPTOR ANGIOTENSIN-CONVERTING ENZYME 2 (ACE2) IN MYALGIC ENCEPHALOMYELITIS/CHRONIC FATIGUE SYNDROME: ANALYSIS OF HIGH-THROUGHPUT EPIGENETIC AND GENE EXPRESSION STUDIES. PATIENTS AFFECTED BY MYALGIC ENCEPHALOMYELITIS/CHRONIC FATIGUE SYNDROME (ME/CFS) SHOW SPECIFIC EPIGENETIC AND GENE EXPRESSION SIGNATURES OF THE DISEASE. HOWEVER, IT IS UNKNOWN WHETHER THESE SIGNATURES INCLUDE ABNORMAL LEVELS OF THE HUMAN ANGIOTENSIN-CONVERTING ENZYMES, ACE AND ACE2, THE LATTER BEING THE MAIN RECEPTOR DESCRIBED FOR THE HOST-CELL INVASION BY SARS-COV-2. TO INVESTIGATE THAT, WE FIRST RE-ANALYZED AVAILABLE CASE-CONTROL EPIGENOME-WIDE ASSOCIATION STUDIES BASED ON DNA METHYLATION DATA, AND CASE-CONTROL GENE EXPRESSION STUDIES BASED ON MICROARRAY DATA. FROM THESE PUBLISHED STUDIES, WE FOUND AN ASSOCIATION BETWEEN ME/CFS AND 4 POTENTIALLY HYPOMETHYLATED PROBES LOCATED IN THE ACE LOCUS. WE ALSO FOUND ANOTHER DISEASE ASSOCIATION WITH ONE HYPOMETHYLATED PROBE LOCATED IN THE TRANSCRIPTION START SITE OF ACE2. THE SAME DISEASE ASSOCIATIONS WERE OBTAINED FOR WOMEN BUT NOT FOR MEN AFTER PERFORMING SEX-SPECIFIC ANALYSES. IN CONTRAST, A META-ANALYSIS OF GENE EXPRESSION LEVELS COULD NOT PROVIDE EVIDENCE FOR A DIFFERENTIALLY EXPRESSION OF ACE AND ACE2 IN AFFECTED PATIENTS WHEN COMPARED TO HEALTHY CONTROLS. IN LINE WITH THIS NEGATIVE FINDING, THE ANALYSIS OF A NEW DATA SET ON THE GENE EXPRESSION OF ACE AND ACE2 IN PERIPHERAL BLOOD MONONUCLEAR CELLS DID NOT FIND ANY DIFFERENCES BETWEEN A FEMALE COHORT OF 37 PATIENTS AND 34 AGE-MATCHED HEALTHY CONTROLS. FUTURE STUDIES SHOULD BE CONDUCTED TO EXTEND THIS INVESTIGATION TO OTHER POTENTIAL RECEPTORS USED BY SARS-COV-2. THESE STUDIES WILL HELP RESEARCHERS AND CLINICIANS TO IMPROVE THE UNDERSTANDING OF THE HEALTH RISK IMPOSED BY THIS VIRUS WHEN INFECTING PATIENTS AFFECTED BY THIS DEBILITATING DISEASE. 2021 20 3736 32 INNATE IMMUNE TOLERANCE IN MICROGLIA DOES NOT IMPACT ON CENTRAL NERVOUS SYSTEM PRION DISEASE. PRION DISEASES SUCH AS CREUTZFELDT-JAKOB DISEASE IN HUMANS, BOVINE SPONGIFORM ENCEPHALOPATHY IN CATTLE, AND SCRAPIE IN SHEEP, ARE INFECTIOUS AND CHRONIC NEURODEGENERATIVE DISEASES TO WHICH THERE ARE NO CURES. INFECTION WITH PRIONS IN THE CENTRAL NERVOUS SYSTEM (CNS) ULTIMATELY CAUSES EXTENSIVE NEURODEGENERATION, AND THIS IS ACCOMPANIED BY PROMINENT MICROGLIAL AND ASTROCYTIC ACTIVATION IN AFFECTED REGIONS. THE MICROGLIA ARE THE CNS MACROPHAGES AND HELP MAINTAIN NEURONAL HOMEOSTASIS, CLEAR DEAD OR DYING CELLS AND PROVIDE DEFENSE AGAINST PATHOGENS. THE MICROGLIA ALSO PROVIDE NEUROPROTECTION DURING CNS PRION DISEASE, BUT THEIR PRO-INFLAMMATORY ACTIVATION MAY EXACERBATE THE DEVELOPMENT OF THE NEUROPATHOLOGY. INNATE IMMUNE TOLERANCE INDUCED BY CONSECUTIVE SYSTEMIC BACTERIAL LIPOPOLYSACCHARIDE (LPS) TREATMENT CAN INDUCE LONG-TERM EPIGENETIC CHANGES IN THE MICROGLIA IN THE BRAIN THAT SEVERAL MONTHS LATER CAN DAMPEN THEIR RESPONSIVENESS TO SUBSEQUENT LPS TREATMENT AND IMPEDE THE DEVELOPMENT OF NEURITIC DAMAGE IN A TRANSGENIC MOUSE MODEL OF ALZHEIMER'S DISEASE-LIKE PATHOLOGY. WE THEREFORE REASONED THAT INNATE IMMUNE TOLERANCE IN MICROGLIA MIGHT SIMILARLY IMPEDE THE SUBSEQUENT DEVELOPMENT OF CNS PRION DISEASE. TO TEST THIS HYPOTHESIS GROUPS OF MICE WERE FIRST INFECTED WITH PRIONS BY INTRACEREBRAL INJECTION, AND 35 DAYS LATER GIVEN FOUR CONSECUTIVE SYSTEMIC INJECTIONS WITH LPS TO INDUCE INNATE IMMUNE TOLERANCE. OUR DATA SHOW THAT CONSECUTIVE SYSTEMIC LPS TREATMENT DID NOT AFFECT THE SUBSEQUENT DEVELOPMENT OF CNS PRION DISEASE. OUR DATA SUGGESTS INNATE IMMUNE TOLERANCE IN MICROGLIA DOES NOT INFLUENCE THE SUBSEQUENT ONSET OF PRION DISEASE-INDUCED NEUROPATHOLOGY IN MICE, DESPITE PREVIOUSLY PUBLISHED EVIDENCE OF THIS EFFECT IN AN ALZHEIMER'S DISEASE MOUSE MODEL. 2022