1 1908 163 ENRICHMENT OF GENOMIC PATHWAYS BASED ON DIFFERENTIAL DNA METHYLATION ASSOCIATED WITH CHRONIC POSTSURGICAL PAIN AND ANXIETY IN CHILDREN: A PROSPECTIVE, PILOT STUDY. WE HAVE REPORTED CHILD ANXIETY SENSITIVITY (CHILD ANXIETY SENSITIVITY INDEX [CASI]) PREDICTS CHRONIC POSTSURGICAL PAIN (CPSP). HEREIN, WE EVALUATED DNA METHYLATION PROFILES TO UNDERSTAND THE GENE-ENVIRONMENT INTERACTIONS UNDERLYING CPSP AND CASI, TO IDENTIFY SHARED, ENRICHED, GENOMIC PATHWAYS. IN 73 PROSPECTIVELY RECRUITED ADOLESCENTS UNDERGOING SPINE FUSION, PREOPERATIVE CASI AND PAIN DATA OVER 12 MONTHS AFTER SURGERY WERE COLLECTED. DNA FROM THE PERIPHERAL BLOOD OF EVALUABLE SUBJECTS WITH (N = 16) AND WITHOUT CPSP (N = 40) WERE ANALYZED USING METHYLATIONEPIC ARRAYS. WE IDENTIFIED 637 AND 2,445 DIFFERENTIALLY DNA METHYLATED POSITIONS (DMPS) ASSOCIATED WITH CPSP AND CASI, RESPECTIVELY (P 350 MILLION PEOPLE WORLDWIDE, AND EXERTS SUBSTANTIAL PUBLIC HEALTH AND FINANCIAL COSTS TO SOCIETY. THUS, THERE IS A SIGNIFICANT NEED TO DISCOVER INNOVATIVE THERAPEUTICS TO TREAT DEPRESSION EFFICIENTLY. STRESS-INDUCED DYSFUNCTION IN THE SUBTYPE OF NEURONAL CELLS AND THE CHANGE OF SYNAPTIC PLASTICITY AND STRUCTURAL PLASTICITY OF NUCLEUS ACCUMBENS (NAC) ARE IMPLICATED IN DEPRESSION SYMPTOMOLOGY. HOWEVER, THE MOLECULAR AND EPIGENETIC MECHANISMS AND STRESSES TO THE NAC PATHOLOGICAL CHANGES IN DEPRESSION REMAIN ELUSIVE. MATERIALS AND METHODS: IN THIS STUDY, TREATMENT GROUP MICE WERE TREATED CONTINUALLY WITH THE CHRONIC UNPREDICTABLE MILD STRESS (CUMS) UNTIL EXPRESSION OF DEPRESSION-LIKE BEHAVIORS WERE FOUND. DEPRESSION WAS CONFIRMED WITH SUCROSE PREFERENCE, NOVELTY-SUPPRESSED FEEDING, FORCED SWIMMING, AND TAIL SUSPENSION TESTS. WE APPLIED HIGH-THROUGHPUT RNA SEQUENCING TO ASSESS MICRORNA EXPRESSION AND TRANSCRIPTIONAL PROFILES IN THE NAC TISSUE FROM DEPRESSION-LIKE BEHAVIORS MICE AND CONTROL MICE. THE REGULATORY NETWORK OF MIRNAS/MRNAS WAS CONSTRUCTED BASED ON THE HIGH-THROUGHPUT RNA SEQUENCE AND BIOINFORMATICS SOFTWARE PREDICTIONS. RESULTS: A TOTAL OF 17 MIRNAS AND 10 MRNAS WERE SIGNIFICANTLY UPREGULATED IN THE NAC OF CUMS-INDUCED MICE WITH DEPRESSION-LIKE BEHAVIORS, AND 12 MIRNAS AND 29 MRNAS WERE DOWNREGULATED. A SERIES OF BIOINFORMATICS ANALYSES SHOWED THAT THESE ALTERED MIRNAS PREDICTED TARGET MRNA AND DIFFERENTIALLY EXPRESSED MRNAS WERE SIGNIFICANTLY ENRICHED IN THE MAPK SIGNALING PATHWAY, GABAERGIC SYNAPSE, DOPAMINERGIC SYNAPSE, CYTOKINE-CYTOKINE RECEPTOR INTERACTION, AXON GUIDANCE, REGULATION OF AUTOPHAGY, AND SO ON. FURTHERMORE, DUAL LUCIFERASE REPORT ASSAY AND QRT-PCR RESULTS VALIDATED THE MIRNA/MRNA REGULATORY NETWORK. CONCLUSION: THE DETERIORATIONS OF GABAERGIC SYNAPSES, DOPAMINERGIC SYNAPSES, NEUROTRANSMITTER SYNTHESIS, AS WELL AS AUTOPHAGY-ASSOCIATED APOPTOTIC PATHWAY ARE ASSOCIATED WITH THE MOLECULAR PATHOLOGICAL MECHANISM OF CUMS-INDUCED DEPRESSION. 2019 14 1580 40 DNA METHYLATION PROFILES ARE ASSOCIATED WITH COMPLEX REGIONAL PAIN SYNDROME AFTER TRAUMATIC INJURY. FACTORS CONTRIBUTING TO DEVELOPMENT OF COMPLEX REGIONAL PAIN SYNDROME (CRPS) ARE NOT FULLY UNDERSTOOD. THIS STUDY EXAMINED POSSIBLE EPIGENETIC MECHANISMS THAT MAY CONTRIBUTE TO CRPS AFTER TRAUMATIC INJURY. DNA METHYLATION PROFILES WERE COMPARED BETWEEN INDIVIDUALS DEVELOPING CRPS (N = 9) AND THOSE DEVELOPING NON-CRPS NEUROPATHIC PAIN (N = 38) AFTER UNDERGOING AMPUTATION FOLLOWING MILITARY TRAUMA. LINEAR MODELS FOR MICROARRAY (LIMMA) ANALYSES REVEALED 48 DIFFERENTIALLY METHYLATED CYTOSINE-PHOSPHATE-GUANINE DINUCLEOTIDE (CPG) SITES BETWEEN GROUPS (UNADJUSTED P'S < 0.005), WITH THE TOP GENE COL11A1 MEETING BONFERRONI-ADJUSTED P < 0.05. THE SECOND LARGEST DIFFERENTIAL METHYLATION WAS OBSERVED FOR THE HLA-DRB6 GENE, AN IMMUNE-RELATED GENE LINKED PREVIOUSLY TO CRPS IN A SMALL GENE EXPRESSION STUDY. FOR ALL BUT 7 OF THE SIGNIFICANT CPG SITES, THE CRPS GROUP WAS HYPOMETHYLATED. NUMEROUS FUNCTIONAL GENE ONTOLOGY-BIOLOGICAL PROCESS CATEGORIES WERE SIGNIFICANTLY ENRICHED (FALSE DISCOVERY RATE-ADJUSTED Q VALUE <0.15), INCLUDING MULTIPLE IMMUNE-RELATED CATEGORIES (EG, ACTIVATION OF IMMUNE RESPONSE, IMMUNE SYSTEM DEVELOPMENT, REGULATION OF IMMUNE SYSTEM PROCESSES, AND ANTIGEN PROCESSING AND PRESENTATION). DIFFERENTIALLY METHYLATED GENES WERE MORE HIGHLY CONNECTED IN HUMAN PROTEIN-PROTEIN NETWORKS THAN EXPECTED BY CHANCE (P < 0.05), SUPPORTING THE BIOLOGICAL RELEVANCE OF THE FINDINGS. RESULTS WERE VALIDATED IN AN INDEPENDENT SAMPLE LINKING A DNA BIOBANK WITH ELECTRONIC HEALTH RECORDS (N = 126 CRPS PHENOTYPE, N = 19,768 NON-CRPS CHRONIC PAIN PHENOTYPE). ANALYSES USING PREDIXCAN METHODOLOGY INDICATED DIFFERENCES IN THE GENETICALLY DETERMINED COMPONENT OF GENE EXPRESSION IN 7 OF 48 GENES IDENTIFIED IN METHYLATION ANALYSES (P'S < 0.02). RESULTS SUGGEST THAT IMMUNE- AND INFLAMMATORY-RELATED FACTORS MIGHT CONFER RISK OF DEVELOPING CRPS AFTER TRAUMATIC INJURY. VALIDATION FINDINGS DEMONSTRATE THE POTENTIAL OF USING ELECTRONIC HEALTH RECORDS LINKED TO DNA FOR GENOMIC STUDIES OF CRPS. 2019 15 89 47 A PILOT INVESTIGATION OF DIFFERENTIAL HYDROXYMETHYLATION LEVELS IN PATIENT-DERIVED NEURAL STEM CELLS IMPLICATES ALTERED CORTICAL DEVELOPMENT IN BIPOLAR DISORDER. INTRODUCTION: BIPOLAR DISORDER (BD) IS A CHRONIC MENTAL ILLNESS CHARACTERIZED BY RECURRENT EPISODES OF MANIA AND DEPRESSION AND ASSOCIATED WITH SOCIAL AND COGNITIVE DISTURBANCES. ENVIRONMENTAL FACTORS, SUCH AS MATERNAL SMOKING AND CHILDHOOD TRAUMA, ARE BELIEVED TO MODULATE RISK GENOTYPES AND CONTRIBUTE TO THE PATHOGENESIS OF BD, SUGGESTING A KEY ROLE IN EPIGENETIC REGULATION DURING NEURODEVELOPMENT. 5-HYDROXYMETHYLCYTOSINE (5HMC) IS AN EPIGENETIC VARIANT OF PARTICULAR INTEREST, AS IT IS HIGHLY EXPRESSED IN THE BRAIN AND IS IMPLICATED IN NEURODEVELOPMENT, AND PSYCHIATRIC AND NEUROLOGICAL DISORDERS. METHODS: INDUCED PLURIPOTENT STEM CELLS (IPSCS) WERE GENERATED FROM THE WHITE BLOOD CELLS OF TWO ADOLESCENT PATIENTS WITH BIPOLAR DISORDER AND THEIR SAME-SEX AGE-MATCHED UNAFFECTED SIBLINGS (N = 4). FURTHER, IPSCS WERE DIFFERENTIATED INTO NEURONAL STEM CELLS (NSCS) AND CHARACTERIZED FOR PURITY USING IMMUNO-FLUORESCENCE. WE USED REDUCED REPRESENTATION HYDROXYMETHYLATION PROFILING (RRHP) TO PERFORM GENOME-WIDE 5HMC PROFILING OF IPSCS AND NSCS, TO MODEL 5HMC CHANGES DURING NEURONAL DIFFERENTIATION AND ASSESS THEIR IMPACT ON BD RISK. FUNCTIONAL ANNOTATION AND ENRICHMENT TESTING OF GENES HARBORING DIFFERENTIATED 5HMC LOCI WERE PERFORMED WITH THE ONLINE TOOL DAVID. RESULTS: APPROXIMATELY 2 MILLION SITES WERE MAPPED AND QUANTIFIED, WITH THE MAJORITY (68.8%) LOCATED IN GENIC REGIONS, WITH ELEVATED 5HMC LEVELS PER SITE OBSERVED FOR 3' UTRS, EXONS, AND 2-KB SHORELINES OF CPG ISLANDS. PAIRED T-TESTS OF NORMALIZED 5HMC COUNTS BETWEEN IPSC AND NSC CELL LINES REVEALED GLOBAL HYPO-HYDROXYMETHYLATION IN NSCS AND ENRICHMENT OF DIFFERENTIALLY HYDROXYMETHYLATED SITES WITHIN GENES ASSOCIATED WITH PLASMA MEMBRANE (FDR = 9.1 X 10(-12)) AND AXON GUIDANCE (FDR = 2.1 X 10(-6)), AMONG OTHER NEURONAL PROCESSES. THE MOST SIGNIFICANT DIFFERENCE WAS OBSERVED FOR A TRANSCRIPTION FACTOR BINDING SITE FOR THE KCNK9 GENE (P = 8.8 X 10(-6)), ENCODING A POTASSIUM CHANNEL PROTEIN INVOLVED IN NEURONAL ACTIVITY AND MIGRATION. PROTEIN-PROTEIN-INTERACTION (PPI) NETWORKING SHOWED SIGNIFICANT CONNECTIVITY (P = 3.2 X 10(-10)) BETWEEN PROTEINS ENCODED BY GENES HARBORING HIGHLY DIFFERENTIATED 5HMC SITES, WITH GENES INVOLVED IN AXON GUIDANCE AND ION TRANSMEMBRANE TRANSPORT FORMING DISTINCT SUB-CLUSTERS. COMPARISON OF NSCS OF BD CASES AND UNAFFECTED SIBLINGS REVEALED ADDITIONAL PATTERNS OF DIFFERENTIATION IN HYDROXYMETHYLATION LEVELS, INCLUDING SITES IN GENES WITH FUNCTIONS RELATED TO SYNAPSE FORMATION AND REGULATION, SUCH AS CUX2 (P = 2.4 X 10(-5)) AND DOK-7 (P = 3.6 X 10(-3)), AS WELL AS AN ENRICHMENT OF GENES INVOLVED IN THE EXTRACELLULAR MATRIX (FDR = 1.0 X 10(-8)). DISCUSSION: TOGETHER, THESE PRELIMINARY RESULTS LEND EVIDENCE TOWARD A POTENTIAL ROLE FOR 5HMC IN BOTH EARLY NEURONAL DIFFERENTIATION AND BD RISK, WITH VALIDATION AND MORE COMPREHENSIVE CHARACTERIZATION TO BE ACHIEVED THROUGH FOLLOW-UP STUDY. 2023 16 4035 35 MACHINE-LEARNED ANALYSIS OF GLOBAL AND GLIAL/OPIOID INTERSECTION-RELATED DNA METHYLATION IN PATIENTS WITH PERSISTENT PAIN AFTER BREAST CANCER SURGERY. BACKGROUND: GLIAL CELLS IN THE CENTRAL NERVOUS SYSTEM PLAY A KEY ROLE IN NEUROINFLAMMATION AND SUBSEQUENT CENTRAL SENSITIZATION TO PAIN. THEY ARE THEREFORE INVOLVED IN THE DEVELOPMENT OF PERSISTENT PAIN. ONE OF THE MAIN SITES OF INTERACTION OF THE IMMUNE SYSTEM WITH PERSISTENT PAIN HAS BEEN IDENTIFIED AS NEURO-IMMUNE CROSSTALK AT THE GLIAL-OPIOID INTERFACE. THE PRESENT STUDY EXAMINED A POTENTIAL ASSOCIATION BETWEEN THE DNA METHYLATION OF TWO KEY PLAYERS OF GLIAL/OPIOID INTERSECTION AND PERSISTENT POSTOPERATIVE PAIN. METHODS: IN A COHORT OF 140 WOMEN WHO HAD UNDERGONE BREAST CANCER SURGERY, AND WERE ASSIGNED BASED ON A 3-YEAR FOLLOW-UP TO EITHER A PERSISTENT OR NON-PERSISTENT PAIN PHENOTYPE, THE ROLE OF EPIGENETIC REGULATION OF KEY PLAYERS IN THE GLIAL-OPIOID INTERFACE WAS ASSESSED. THE METHYLATION OF GENES CODING FOR THE TOLL-LIKE RECEPTOR 4 (TLR4) AS A MAJOR MEDIATOR OF GLIAL CONTRIBUTIONS TO PERSISTENT PAIN OR FOR THE MU-OPIOID RECEPTOR (OPRM1) WAS ANALYZED AND ITS ASSOCIATION WITH THE PAIN PHENOTYPE WAS COMPARED WITH THAT CONFERRED BY GLOBAL GENOME-WIDE DNA METHYLATION ASSESSED VIA QUANTIFICATION OF THE METHYLATION IN THE RETROTRANSPOSON LINE1. RESULTS: TRAINING OF MACHINE LEARNING ALGORITHMS INDICATED THAT THE GLOBAL DNA METHYLATION PROVIDED A SIMILAR DIAGNOSTIC ACCURACY FOR PERSISTENT PAIN AS PREVIOUSLY ESTABLISHED NON-GENETIC PREDICTORS. HOWEVER, THE DIAGNOSIS CAN BE BASED ON A SINGLE DNA BASED MARKER. BY CONTRAST, THE METHYLATION OF TLR4 OR OPRM1 GENES COULD NOT CONTRIBUTE FURTHER TO THE ALLOCATION OF THE PATIENTS TO THE PAIN-RELATED PHENOTYPE GROUPS. CONCLUSIONS: WHILE CLEARLY SUPPORTING A PREDICTIVE UTILITY OF EPIGENETIC TESTING, THE PRESENT ANALYSIS CANNOT PROVIDE SUPPORT FOR SPECIFIC EPIGENETIC MODULATION OF PERSISTENT POSTOPERATIVE PAIN VIA METHYLATION OF TWO KEY GENES OF THE GLIAL-OPIOID INTERFACE. 2019 17 6427 37 THE TRANSITION FROM ACUTE TO CHRONIC PAIN: DYNAMIC EPIGENETIC REPROGRAMMING OF THE MOUSE PREFRONTAL CORTEX UP TO 1 YEAR AFTER NERVE INJURY. CHRONIC PAIN IS ASSOCIATED WITH PERSISTENT STRUCTURAL AND FUNCTIONAL CHANGES THROUGHOUT THE NEUROAXIS, INCLUDING IN THE PREFRONTAL CORTEX (PFC). THE PFC IS IMPORTANT IN THE INTEGRATION OF SENSORY, COGNITIVE, AND EMOTIONAL INFORMATION AND IN CONDITIONED PAIN MODULATION. WE PREVIOUSLY REPORTED WIDESPREAD EPIGENETIC REPROGRAMMING IN THE PFC MANY MONTHS AFTER NERVE INJURY IN RODENTS. EPIGENETIC MODIFICATIONS, INCLUDING DNA METHYLATION, CAN DRIVE CHANGES IN GENE EXPRESSION WITHOUT MODIFYING DNA SEQUENCES. TO DATE, LITTLE IS KNOWN ABOUT EPIGENETIC DYSREGULATION AT THE ONSET OF ACUTE PAIN OR HOW IT PROGRESSES AS PAIN TRANSITIONS FROM ACUTE TO CHRONIC. WE HYPOTHESIZE THAT ACUTE PAIN AFTER INJURY RESULTS IN RAPID AND PERSISTENT EPIGENETIC REMODELLING IN THE PFC THAT EVOLVES AS PAIN BECOMES CHRONIC. WE FURTHER PROPOSE THAT UNDERSTANDING EPIGENETIC REMODELLING WILL PROVIDE INSIGHTS INTO THE MECHANISMS DRIVING PAIN-RELATED CHANGES IN THE BRAIN. EPIGENOME-WIDE ANALYSIS WAS PERFORMED IN THE MOUSE PFC 1 DAY, 2 WEEKS, 6 MONTHS, AND 1 YEAR AFTER PERIPHERAL INJURY USING THE SPARED NERVE INJURY IN MICE. SPARED NERVE INJURY RESULTED IN RAPID AND PERSISTENT CHANGES IN DNA METHYLATION, WITH ROBUST DIFFERENTIAL METHYLATION OBSERVED BETWEEN SPARED NERVE INJURY AND SHAM-OPERATED CONTROL MICE AT ALL TIME POINTS. HUNDREDS OF DIFFERENTIALLY METHYLATED GENES WERE IDENTIFIED, INCLUDING MANY WITH KNOWN FUNCTION IN PAIN. PATHWAY ANALYSIS REVEALED ENRICHMENT IN GENES RELATED TO STIMULUS RESPONSE AT EARLY TIME POINTS, IMMUNE FUNCTION AT LATER TIME POINTS, AND ACTIN AND CYTOSKELETAL REGULATION THROUGHOUT THE TIME COURSE. THESE RESULTS EMPHASIZE THE IMPORTANCE OF CONSIDERING PAIN CHRONICITY IN BOTH PAIN RESEARCH AND IN TREATMENT OPTIMIZATION. 2020 18 3056 38 GENOME-WIDE DNA METHYLATION ANALYSIS IMPLICATES ENRICHMENT OF INTERFERON PATHWAY IN AFRICAN AMERICAN PATIENTS WITH SYSTEMIC LUPUS ERYTHEMATOSUS AND EUROPEAN AMERICANS WITH LUPUS NEPHRITIS. SYSTEMIC LUPUS ERYTHEMATOSUS (SLE) IS A CHRONIC, MULTISYSTEM, INFLAMMATORY AUTOIMMUNE DISEASE THAT DISPROPORTIONATELY AFFECTS WOMEN. TRENDS IN SLE PREVALENCE AND CLINICAL COURSE DIFFER BY ANCESTRY, WITH THOSE OF AFRICAN AMERICAN ANCESTRY PRESENTING WITH MORE ACTIVE, SEVERE AND RAPIDLY PROGRESSIVE DISEASE THAN EUROPEAN AMERICANS. PREVIOUS RESEARCH ESTABLISHED ALTERED EPIGENETIC SIGNATURES IN SLE PATIENTS COMPARED TO CONTROLS. HOWEVER, THE CONTRIBUTION OF ABERRANT DNA METHYLATION (DNAM) TO THE RISK OF SLE BY ANCESTRY AND DIFFERENCES AMONG PATIENTS WITH SLE-ASSOCIATED LUPUS NEPHRITIS (LN) HAS NOT BEEN WELL DESCRIBED. WE EVALUATED THE DNA METHYLOMES OF 87 INDIVIDUALS INCLUDING 41 SLE PATIENTS, WITH AND WITHOUT LN, AND 46 CONTROLS ENROLLED IN AN ANCESTRY DIVERSE, WELL-CHARACTERIZED COHORT STUDY OF ESTABLISHED SLE (41 SLE PATIENTS [20 SLE-LN+, 21 SLE-LN-] AND 46 SEX-, RACE- AND AGE-MATCHED CONTROLS; 55% AFRICAN AMERICAN, 45% EUROPEAN AMERICAN). PARTICIPANTS WERE GENOTYPED USING THE INFINIUM GLOBAL DIVERSITY ARRAY (GDA), AND GENETIC ANCESTRY WAS ESTIMATED USING PRINCIPAL COMPONENTS. GENOME-WIDE DNA METHYLATION WAS INITIALLY MEASURED USING THE ILLUMINA METHYLATIONEPIC 850K BEADCHIP ARRAY FOLLOWED BY METHYLATION-SPECIFIC QPCR TO VALIDATE THE METHYLATION STATUS AT PUTATIVE LOCI. DIFFERENTIALLY METHYLATED POSITIONS (DMP) WERE IDENTIFIED USING A CASE-CONTROL APPROACH ADJUSTED FOR ANCESTRY. WE IDENTIFIED A TOTAL OF 51 DMPS IN CPGS AMONG SLE PATIENTS COMPARED TO CONTROLS. GENES PROXIMAL TO THESE CPGS WERE HIGHLY ENRICHED FOR INVOLVEMENT IN TYPE I INTERFERON SIGNALING. DMPS AMONG EUROPEAN AMERICAN SLE PATIENTS WITH LN WERE SIMILAR TO AFRICAN AMERICAN SLE PATIENTS WITH AND WITHOUT LN. OUR FINDINGS WERE VALIDATED USING AN ORTHOGONAL, METHYL-SPECIFIC PCR FOR THREE SLE-ASSOCIATED DMPS NEAR OR PROXIMAL TO MX1, USP18, AND IFITM1. OUR STUDY CONFIRMS PREVIOUS REPORTS THAT DMPS IN CPGS ASSOCIATED WITH SLE ARE ENRICHED IN TYPE I INTERFERON GENES. HOWEVER, WE SHOW THAT EUROPEAN AMERICAN SLE PATIENTS WITH LN HAVE SIMILAR DNAM PATTERNS TO AFRICAN AMERICAN SLE PATIENTS IRRESPECTIVE OF LN, SUGGESTING THAT ABERRANT DNAM ALTERS ACTIVITY OF TYPE I INTERFERON PATHWAY LEADING TO MORE SEVERE DISEASE INDEPENDENT OF ANCESTRY. 2023 19 4304 28 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 20 3380 27 HIV-1 INFECTION OF GENETICALLY ENGINEERED IPSC-DERIVED CENTRAL NERVOUS SYSTEM-ENGRAFTED MICROGLIA IN A HUMANIZED MOUSE MODEL. THE CENTRAL NERVOUS SYSTEM (CNS) IS A MAJOR HUMAN IMMUNODEFICIENCY VIRUS TYPE 1 RESERVOIR. MICROGLIA ARE THE PRIMARY TARGET CELL OF HIV-1 INFECTION IN THE CNS. CURRENT MODELS HAVE NOT ALLOWED THE PRECISE MOLECULAR PATHWAYS OF ACUTE AND CHRONIC CNS MICROGLIAL INFECTION TO BE TESTED WITH IN VIVO GENETIC METHODS. HERE, WE DESCRIBE A NOVEL HUMANIZED MOUSE MODEL UTILIZING HUMAN-INDUCED PLURIPOTENT STEM CELL-DERIVED MICROGLIA TO XENOGRAFT INTO MURINE HOSTS. THESE MICE ARE ADDITIONALLY ENGRAFTED WITH HUMAN PERIPHERAL BLOOD MONONUCLEAR CELLS THAT SERVED AS A MEDIUM TO ESTABLISH A PERIPHERAL INFECTION THAT THEN SPREAD TO THE CNS MICROGLIA XENOGRAFT, MODELING A TRANS-BLOOD-BRAIN BARRIER ROUTE OF ACUTE CNS HIV-1 INFECTION WITH HUMAN TARGET CELLS. THE APPROACH IS COMPATIBLE WITH IPSC GENETIC ENGINEERING, INCLUDING INSERTING TARGETED TRANSGENIC REPORTER CASSETTES TO TRACK THE XENOGRAFTED HUMAN CELLS, ENABLING THE TESTING OF NOVEL TREATMENT AND VIRAL TRACKING STRATEGIES IN A COMPARATIVELY SIMPLE AND COST-EFFECTIVE WAY VIVO MODEL FOR NEUROHIV. IMPORTANCE: OUR MOUSE MODEL IS A POWERFUL TOOL FOR INVESTIGATING THE GENETIC MECHANISMS GOVERNING CNS HIV-1 INFECTION AND LATENCY IN THE CNS AT A SINGLE-CELL LEVEL. A MAJOR ADVANTAGE OF OUR MODEL IS THAT IT USES IPSC-DERIVED MICROGLIA, WHICH ENABLES HUMAN GENETICS, INCLUDING GENE FUNCTION AND THERAPEUTIC GENE MANIPULATION, TO BE EXPLORED IN VIVO , WHICH IS MORE CHALLENGING TO STUDY WITH CURRENT HEMATOPOIETIC STEM CELL-BASED MODELS FOR NEUROHIV. OUR TRANSGENIC TRACING OF XENOGRAFTED HUMAN CELLS WILL PROVIDE A QUANTITATIVE MEDIUM TO DEVELOP NEW MOLECULAR AND EPIGENETIC STRATEGIES FOR REDUCING THE HIV-1 LATENT RESERVOIR AND TO TEST THE IMPACT OF THERAPEUTIC INFLAMMATION-TARGETING DRUG INTERVENTIONS ON CNS HIV-1 LATENCY. 2023