1 2927 148 GENERATION OF HUMAN CORTICAL NEURONS FROM A NEW IMMORTAL FETAL NEURAL STEM CELL LINE. ISOLATION AND EXPANSION OF NEURAL STEM CELLS (NSCS) OF HUMAN ORIGIN ARE CRUCIAL FOR SUCCESSFUL DEVELOPMENT OF CELL THERAPY APPROACHES IN NEURODEGENERATIVE DISEASES. DIFFERENT EPIGENETIC AND GENETIC IMMORTALIZATION STRATEGIES HAVE BEEN ESTABLISHED FOR LONG-TERM MAINTENANCE AND EXPANSION OF THESE CELLS IN VITRO. HERE WE REPORT THE GENERATION OF A NEW, CLONAL NSC (HC-NSC) LINE, DERIVED FROM HUMAN FETAL CORTICAL TISSUE, BASED ON V-MYC IMMORTALIZATION. USING IMMUNOCYTOCHEMISTRY, WE SHOW THAT THESE CELLS RETAIN THE CHARACTERISTICS OF NSCS AFTER MORE THAN 50 PASSAGES. UNDER PROLIFERATION CONDITIONS, WHEN SUPPLEMENTED WITH EPIDERMAL AND BASIC FIBROBLAST GROWTH FACTORS, THE HC-NSCS EXPRESSED NEURAL STEM/PROGENITOR CELL MARKERS LIKE NESTIN, VIMENTIN AND SOX2. WHEN GROWTH FACTORS WERE WITHDRAWN, PROLIFERATION AND EXPRESSION OF V-MYC AND TELOMERASE WERE DRAMATICALLY REDUCED, AND THE HC-NSCS DIFFERENTIATED INTO GLIA AND NEURONS (MOSTLY GLUTAMATERGIC AND GABAERGIC, AS WELL AS TYROSINE HYDROXYLASE-POSITIVE, PRESUMABLY DOPAMINERGIC NEURONS). RT-PCR ANALYSIS SHOWED THAT THE HC-NSCS RETAINED EXPRESSION OF PAX6, EMX2 AND NEUROGENIN2, WHICH ARE GENES ASSOCIATED WITH REGIONALIZATION AND CELL COMMITMENT IN CORTICAL PRECURSORS DURING BRAIN DEVELOPMENT. OUR DATA INDICATE THAT THIS HC-NSC LINE COULD BE USEFUL FOR EXPLORING THE POTENTIAL OF HUMAN NSCS TO REPLACE DEAD OR DAMAGED CORTICAL CELLS IN ANIMAL MODELS OF ACUTE AND CHRONIC NEURODEGENERATIVE DISEASES. TAKING ADVANTAGE OF ITS CLONALITY AND HOMOGENEITY, THIS CELL LINE WILL ALSO BE A VALUABLE EXPERIMENTAL TOOL TO STUDY THE REGULATORY ROLE OF INTRINSIC AND EXTRINSIC FACTORS IN HUMAN NSC BIOLOGY. 2007 2 1116 50 COMPARATIVE ANALYSIS OF NEUROECTODERMAL DIFFERENTIATION CAPACITY OF HUMAN BONE MARROW STROMAL CELLS USING VARIOUS CONVERSION PROTOCOLS. HUMAN ADULT BONE MARROW-DERIVED MESODERMAL STROMAL CELLS (HMSCS) ARE ABLE TO DIFFERENTIATE INTO MULTIPLE MESODERMAL TISSUES, INCLUDING BONE AND CARTILAGE. THERE IS EVIDENCE THAT THESE CELLS ARE ABLE TO BREAK GERM LAYER COMMITMENT AND DIFFERENTIATE INTO CELLS EXPRESSING NEUROECTODERMAL PROPERTIES. THERE IS STILL DEBATE ABOUT WHETHER THIS RESULTS FROM CELL FUSION, ABERRANT MARKER GENE EXPRESSION OR REAL NEUROECTODERMAL DIFFERENTIATION. HERE WE EXTEND OUR WORK ON NEUROECTODERMAL CONVERSION OF ADULT HMSCS IN VITRO BY EVALUATING VARIOUS EPIGENETIC CONVERSION PROTOCOLS USING QUANTITATIVE RT-PCR AND IMMUNOCYTOCHEMISTRY. UNDIFFERENTIATED HMSCS EXPRESSED HIGH LEVELS OF FIBRONECTIN AS WELL AS SEVERAL NEUROECTODERMAL GENES COMMONLY USED TO CHARACTERIZE NEURAL CELL TYPES, SUCH AS NESTIN, BETA-TUBULIN III, AND GFAP, SUGGESTING THAT HMSCS RETAIN THE ABILITY TO DIFFERENTIATE INTO NEUROECTODERMAL CELL TYPES. PROTOCOLS USING A DIRECT DIFFERENTIATION OF HMSCS INTO A NEURAL PHENOTYPE FAILED TO INDUCE SIGNIFICANT CHANGES IN MORPHOLOGY AND/OR EXPRESSION OF MARKERS OF EARLY AND MATURE GLIAL/NEURONAL CELLS TYPES. IN CONTRAST, A MULTISTEP PROTOCOL WITH CONVERSION OF HMSCS INTO A NEURAL STEM CELL-LIKE POPULATION AND SUBSEQUENT TERMINAL DIFFERENTIATION IN MATURE GLIA AND NEURONS GENERATED RELEVANT MORPHOLOGICAL CHANGES AS WELL AS SIGNIFICANT INCREASE OF EXPRESSION LEVELS OF MARKER GENES FOR EARLY AND LATE NEURAL CELL TYPES, SUCH AS NESTIN, NEUROGENIN2, MBP, AND MAP2AB, ACCOMPANIED BY A LOSS OF THEIR MESENCHYMAL PROPERTIES. OUR DATA PROVIDE AN IMPETUS FOR DIFFERENTIATING HMSCS IN VITRO INTO MATURE NEUROECTODERMAL CELLS. NEUROECTODERMALLY CONVERTED HMSCS MAY THEREFORE ULTIMATELY HELP IN TREATING ACUTE AND CHRONIC NEURODEGENERATIVE DISEASES. ANALYSIS OF MARKER GENE EXPRESSION FOR CHARACTERIZATION OF NEURAL CELLS DERIVED FROM MSCS HAS TO TAKE INTO ACCOUNT THAT SEVERAL EARLY AND LATE NEUROECTODERMAL GENES ARE ALREADY EXPRESSED IN UNDIFFERENTIATED MSCS. 2006 3 5785 33 SPONTANEOUS NEOPLASTIC TRANSFORMATION OF WB-F344 RAT LIVER EPITHELIAL CELLS. SEVERAL STUDIES HAVE SHOWN THAT CULTURED RAT LIVER EPITHELIAL CELLS TRANSFORM SPONTANEOUSLY AFTER CHRONIC MAINTENANCE IN A CONFLUENT STATE IN VITRO. IN THE PRESENT STUDY, MULTIPLE INDEPENDENT LINEAGES OF LOW-PASSAGE WB-F344 RAT LIVER EPITHELIAL STEM-LIKE CELLS WERE INITIATED AND SUBJECTED IN PARALLEL TO SELECTION FOR SPONTANEOUS TRANSFORMATION TO DETERMINE WHETHER SPONTANEOUS ACQUISITION OF TUMORIGENICITY WAS THE RESULT OF EVENTS (GENETIC OR EPIGENETIC) THAT OCCURRED INDEPENDENTLY AND STOCHASTICALLY, OR REFLECTED THE EXPRESSION OF A PRE-EXISTING ALTERATION WITHIN THE PARENTAL WB-F344 CELL LINE. TEMPORAL ANALYSIS OF THE SPONTANEOUS ACQUISITION OF TUMORIGENICITY BY WB-F344 CELLS DEMONSTRATED LINEAGE-SPECIFIC DIFFERENCES IN THE TIME OF FIRST EXPRESSION OF THE TUMORIGENIC PHENOTYPE, FREQUENCIES AND LATENCIES OF TUMOR FORMATION, AND TUMOR DIFFERENTIATIONS. ALTHOUGH SPONTANEOUSLY TRANSFORMED WB-F344 CELLS PRODUCED DIVERSE TUMOR TYPES (INCLUDING HEPATOCELLULAR CARCINOMAS, CHOLANGIOCARCINOMAS, HEPATOBLASTOMAS, AND OSTEOGENIC SARCOMAS), INDIVIDUAL LINEAGES YIELDED TUMORS WITH CONSISTENT AND SPECIFIC PATTERNS OF DIFFERENTIATION. THESE RESULTS PROVIDE SUBSTANTIAL EVIDENCE THAT THE STOCHASTIC ACCUMULATION OF INDEPENDENT TRANSFORMING EVENTS DURING THE SELECTION REGIMEN IN VITRO WERE RESPONSIBLE FOR SPONTANEOUS NEOPLASTIC TRANSFORMATION OF WB-F344 CELLS. FURTHERMORE, CELL LINEAGE COMMITMENT TO A SPECIFIC DIFFERENTIATION PROGRAM WAS STABLE WITH TIME IN CULTURE AND WITH SITE OF TRANSPLANTATION. THIS IS THE FIRST REPORT OF A COHORT OF RELATED, BUT INDEPENDENT, RAT LIVER EPITHELIAL CELL LINES THAT COLLECTIVELY PRODUCE A SPECTRUM OF TUMOR TYPES BUT INDIVIDUALLY REPRODUCE A SPECIFIC TUMOR TYPE. THESE CELL LINES WILL PROVIDE VALUABLE REAGENTS FOR INVESTIGATION OF THE MOLECULAR MECHANISMS INVOLVED IN THE DIFFERENTIATION OF HEPATIC STEM-LIKE CELLS AND FOR EXAMINATION OF POTENTIAL CAUSAL RELATIONSHIPS IN SPONTANEOUSLY TRANSFORMED RAT LIVER EPITHELIAL CELL LINES BETWEEN MOLECULAR/CELLULAR ALTERATIONS AND THE ABILITY TO PRODUCE TUMORS IN SYNGENEIC ANIMALS. 1998 4 6895 23 [SYSTEMIC CONTROL OF THE MOLECULAR, CELL, AND EPIGENETIC MECHANISMS OF LONG-LASTING CONSEQUENCES OF STRESS]. BASED ON M.E. LOBASHEV'S VIEWS OF THE SYSTEMIC CONTROL OF GENETIC AND CYTOGENEITC PROCESSES AND A SUBSTANTIAL EFFECT OF EXCITABILITY ON PLASTIC CHANGES IN THE CENTRAL NERVOUS SYSTEM (CNS), THE EFFECT OF PROLONGED EMOTIONAL AND PAIN STRESS (PEPS) ON THE MOLECULAR, CELL, AND EPIGENETIC MECHANISMS OF INJURY MEMORY WAS STUDIED IN RAT STRAINS BRED FOR A CERTAIN EXCITABILITY OF THE NERVOUS SYSTEM. PEPS WAS FOR THE FIRST TIME FOUND TO CAUSE LONG-LASTING (2 MONTHS) MORPHOLOGICAL ALTERATIONS OF THE CA3 REGION OF THE HIPPOCAMPUS AND TO MODIFY THE GENOME ACTIVITY OF ITS PYRAMIDAL NEURONS. THE TWO PHENOMENA WERE POTENTIATED BY A GENETICALLY DETERMINED LOW FUNCTIONAL STATE OF THE CNS. THE POST-STRESS REGULATION OF THE GENOME FUNCTION IN HIPPOCAMPAL NEURONS WAS MEDIATED BY CHANGES IN HETEROCHROMATIN CONFORMATION, ACTIVATION OF METHYL-CPG-BINDING PROTEIN (MECP2) SYNTHESIS, AND SUBSEQUENT CHANGES IN ACETYLATION OF HISTONE H4. GENETICALLY DETERMINED HIGH EXCITABILITY OF THE NERVOUS SYSTEM PROVED TO BE A RISK FACTOR THAT AFFECTS THE SPECIFICS AND TIME COURSE OF THE OBSERVED MOLECULAR, CELL, AND GENETIC TRANSFORMATIONS OF NEURONS. THE RESULTS PROVIDE FOR A BETTER UNDERSTANDING OF THE EPIGENETIC MECHANISMS OF INJURY MEMORY, WHICH FORMS A PATHOGENETIC BASIS FOR POSTTRAUMATIC STRESS DISORDER AND OTHER HUMAN PSYCHOGENIC CONDITIONS CHARACTERIZED BY A PROLONGED DURATION. 2009 5 1162 31 CONTRASTING EFFECTS OF ACUTE AND CHRONIC STRESS ON THE TRANSCRIPTOME, EPIGENOME, AND IMMUNE RESPONSE OF ATLANTIC SALMON. STRESS EXPERIENCED DURING EARLY LIFE MAY HAVE LASTING EFFECTS ON THE IMMUNE SYSTEM, WITH IMPACTS ON HEALTH AND DISEASE DEPENDENT ON THE NATURE AND DURATION OF THE STRESSOR. THE EPIGENOME IS ESPECIALLY SENSITIVE TO ENVIRONMENTAL STIMULI DURING EARLY LIFE AND REPRESENTS A POTENTIAL MECHANISM THROUGH WHICH STRESS MAY CAUSE LONG-LASTING HEALTH EFFECTS. HOWEVER, THE EXTENT TO WHICH THE EPIGENOME RESPONDS DIFFERENTLY TO CHRONIC VS ACUTE STRESSORS IS UNCLEAR, ESPECIALLY FOR NON-MAMMALIAN SPECIES. WE EXAMINED THE EFFECTS OF ACUTE STRESS (COLD-SHOCK DURING EMBRYOGENESIS) AND CHRONIC STRESS (ABSENCE OF TANK ENRICHMENT DURING LARVAL-STAGE) ON GLOBAL GENE EXPRESSION (USING RNA-SEQ) AND DNA METHYLATION (USING RRBS) IN THE GILLS OF ATLANTIC SALMON (SALMO SALAR) FOUR MONTHS AFTER HATCHING. CHRONIC STRESS INDUCED PRONOUNCED TRANSCRIPTIONAL DIFFERENCES, WHILE ACUTE STRESS CAUSED FEW LASTING TRANSCRIPTIONAL EFFECTS. HOWEVER, BOTH ACUTE AND CHRONIC STRESS CAUSED LASTING AND CONTRASTING CHANGES IN THE METHYLOME. CRUCIALLY, WE FOUND THAT ACUTE STRESS ENHANCED TRANSCRIPTIONAL IMMUNE RESPONSE TO A PATHOGENIC CHALLENGE (BACTERIAL LIPOPOLYSACCHARIDE, LPS), WHILE CHRONIC STRESS SUPPRESSED IT. WE IDENTIFIED STRESS-INDUCED CHANGES IN PROMOTER AND GENE-BODY METHYLATION THAT WERE ASSOCIATED WITH ALTERED EXPRESSION FOR A SMALL PROPORTION OF IMMUNE-RELATED GENES, AND EVIDENCE OF WIDER EPIGENETIC REGULATION WITHIN SIGNALLING PATHWAYS INVOLVED IN IMMUNE RESPONSE. OUR RESULTS SUGGEST THAT STRESS CAN AFFECT IMMUNO-COMPETENCE THROUGH EPIGENETIC MECHANISMS, AND HIGHLIGHT THE MARKEDLY DIFFERENT EFFECTS OF CHRONIC LARVAL AND ACUTE EMBRYONIC STRESS. THIS KNOWLEDGE COULD BE USED TO HARNESS THE STIMULATORY EFFECTS OF ACUTE STRESS ON IMMUNITY, PAVING THE WAY FOR IMPROVED STRESS AND DISEASE MANAGEMENT THROUGH EPIGENETIC CONDITIONING. 2018 6 1584 29 DNA METHYLATION PROFILES OF SELECTED PRO-INFLAMMATORY CYTOKINES IN ALZHEIMER DISEASE. BY MEANS OF FUNCTIONAL GENOMICS ANALYSIS, WE RECENTLY DESCRIBED THE MRNA EXPRESSION PROFILES OF VARIOUS GENES INVOLVED IN THE NEUROINFLAMMATORY RESPONSE IN THE BRAINS OF SUBJECTS WITH LATE-ONSET ALZHEIMER DISEASE (LOAD). SOME OF THESE GENES, NAMELY INTERLEUKIN (IL)-1BETA AND IL-6, SHOWED DISTINCT EXPRESSION PROFILES WITH PEAK EXPRESSION DURING THE FIRST STAGES OF THE DISEASE AND CONTROL-LIKE LEVELS AT LATER STAGES. IL-1BETA AND IL-6 GENES ARE MODULATED BY DNA METHYLATION IN DIFFERENT CHRONIC AND DEGENERATIVE DISEASES; IT IS ALSO WELL KNOWN THAT LOAD MAY HAVE AN EPIGENETIC BASIS. INDEED, WE AND OTHERS HAVE PREVIOUSLY REPORTED GENE-SPECIFIC DNA METHYLATION ALTERATIONS IN LOAD AND IN RELATED ANIMAL MODELS. BASED ON THESE DATA, WE STUDIED THE DNA METHYLATION PROFILES, AT SINGLE CYTOSINE RESOLUTION, OF IL-1BETA AND IL-6 5'-FLANKING REGION BY BISULPHITE MODIFICATION IN THE CORTEX OF HEALTHY CONTROLS AND LOAD PATIENTS AT 2 DIFFERENT DISEASE STAGES: BRAAK I-II/A AND BRAAK V-VI/C. OUR ANALYSIS PROVIDES EVIDENCE THAT NEUROINFLAMMATION IN LOAD IS ASSOCIATED WITH (AND POSSIBLY MEDIATED BY) EPIGENETIC MODIFICATIONS. 2017 7 6137 32 THE EPIGENETICS OF PSYCHOSIS: A STRUCTURED REVIEW WITH REPRESENTATIVE LOCI. THE EVIDENCE FOR AN ENVIRONMENTAL COMPONENT IN CHRONIC PSYCHOTIC DISORDERS IS STRONG AND RESEARCH ON THE EPIGENETIC MANIFESTATIONS OF THESE ENVIRONMENTAL IMPACTS HAS COMMENCED IN EARNEST. IN REVIEWING THIS RESEARCH, THE FOCUS IS ON THREE GENES AS MODELS FOR DIFFERENTIAL METHYLATION, MCHR1, AKT1 AND TDO2, EACH OF WHICH HAVE BEEN INVESTIGATED FOR GENETIC ASSOCIATION WITH PSYCHOTIC DISORDERS. ENVIRONMENTAL FACTORS ASSOCIATED WITH PSYCHOTIC DISORDERS, AND WHICH INTERACT WITH THESE MODEL GENES, ARE EXPLORED IN DEPTH. THE LOCATION OF TRANSCRIPTION FACTOR MOTIFS RELATIVE TO KEY METHYLATION SITES IS EVALUATED FOR PREDICTED GENE EXPRESSION RESULTS, AND FOR OTHER SITES, EVIDENCE IS PRESENTED FOR METHYLATION DIRECTING ALTERNATIVE SPLICING. EXPERIMENTAL RESULTS FROM KEY STUDIES SHOW DIFFERENTIAL METHYLATION: FOR MCHR1, IN PSYCHOSIS CASES VERSUS CONTROLS; FOR AKT1, AS A PRE-EXISTING METHYLATION PATTERN INFLUENCING BRAIN ACTIVATION FOLLOWING ACUTE ADMINISTRATION OF A PSYCHOSIS-ELICITING ENVIRONMENTAL STIMULUS; AND FOR TDO2, IN A PATTERN ASSOCIATED WITH A DEVELOPMENTAL FACTOR OF RISK FOR PSYCHOSIS, IN ALL CASES THE PREDICTED EXPRESSION IMPACT BEING HIGHLY DEPENDENT ON LOCATION. METHYLATION INDUCED BY SMOKING, A CONFOUNDING VARIABLE, EXHIBITS AN INTRIGUING PATTERN FOR ALL THREE GENES. FINALLY, HOW DIFFERENTIAL METHYLATION MESHES WITH DARWINIAN PRINCIPLES IS EXAMINED, IN PARTICULAR AS IT RELATES TO THE "FLEXIBLE STEM" THEORY OF EVOLUTION. 2022 8 3418 29 HUMAN HEALTH CONSEQUENCES OF ENVIRONMENTALLY-MODULATED GENE EXPRESSION: POTENTIAL ROLES OF ELF-EMF INDUCED EPIGENETIC VERSUS MUTAGENIC MECHANISMS OF DISEASE. IN ORDER TO DETERMINE IF THERE MIGHT BE BIOLOGICAL AND HEALTH CONSEQUENCES AFTER EXPOSURES TO EXTREMELY-LOW FREQUENCY ELECTROMAGNETIC FIELDS (ELF-EMF), EITHER EXPERIMENTALLY OR EPIDEMIOLOGICALLY, MECHANISTIC UNDERSTANDING OF THE POTENTIAL MEANS BY WHICH ANY ENVIRONMENTAL AGENT CAN AFFECT CELLS IN A MULTICELLULAR ORGANISM HAS TO BE REVIEWED. THE GOAL OF THIS LIMITED REVIEW IS TO DEMONSTRATE THAT, WHILE THE PREVAILING PARADIGM OF THE ENVIRONMENTALLY-INDUCED ACUTE AND CHRONIC DISEASES INVOLVES EITHER CELL KILLING (CYTOTOXICITY) OR GENE/CHROMOSOME MUTATIONS (GENOTOXICITY), ALTERATION OF THE EXPRESSION OF GENETIC INFORMATION AT THE TRANSCRIPTIONAL (TURNING GENES "ON" OR "OFF"), TRANSLATIONAL (STABILIZING OR DE-STABILIZING THE GENETIC MESSAGE), OR POSTTRANSLATIONAL (ALTERING THE GENE PRODUCT OR PROTEIN) LEVELS HAS THE POTENTIAL TO CONTRIBUTE TO VARIOUS DISEASES. THIS LATTER MECHANISM, "EPIGENETIC" TOXICITY, UNLIKE THE FORMER TWO WHICH ARE IRREVERSIBLE, IS CHARACTERIZED BY THRESHOLD-LIKE ACTION, MULTIPLE BIOCHEMICAL PATHWAYS AND CHRONIC, REGULAR EXPOSURES TO BE EFFECTIVE. ULTIMATELY, EPIGENETIC TOXICANTS AFFECT ONE OF FOUR POTENTIAL CELL STATES, NAMELY ALTERATION OF CELL PROLIFERATION, CELL DIFFERENTIATION, PROGRAMMED CELL DEATH (APOPTOSIS) OR ADAPTIVE RESPONSES OF DIFFERENTIATED CELLS. 2000 9 2776 36 EXTRAUTERINE GROWTH RESTRICTION ON PULMONARY VASCULAR ENDOTHELIAL DYSFUNCTION IN ADULT MALE RATS: THE ROLE OF EPIGENETIC MECHANISMS. OBJECTIVE: EARLY POSTNATAL LIFE IS CONSIDERED AS A CRITICAL TIME WINDOW FOR THE DETERMINATION OF LONG-TERM METABOLIC STATES AND ORGAN FUNCTIONS. EXTRAUTERINE GROWTH RESTRICTION (EUGR) CAUSES THE DEVELOPMENT OF ADULT-ONSET CHRONIC DISEASES, INCLUDING PULMONARY HYPERTENSION. HOWEVER, THE EFFECTS OF NUTRITIONAL DISADVANTAGES DURING THE EARLY POSTNATAL PERIOD ON PULMONARY VASCULAR CONSEQUENCES IN LATER LIFE ARE NOT FULLY UNDERSTOOD. OUR STUDY WAS DESIGNED TO TEST WHETHER EPIGENETICS DYSREGULATION MEDIATES THE CELLULAR MEMORY OF THIS EARLY POSTNATAL EVENT. METHODS AND RESULTS: TO TEST THIS HYPOTHESIS, WE ISOLATED PULMONARY VASCULAR ENDOTHELIAL CELLS BY MAGNETIC-ACTIVATED CELL SORTING FROM EUGR AND CONTROL RATS. A POSTNATAL INSULT, NUTRITIONAL RESTRICTION-INDUCED EUGR CAUSED DEVELOPMENT OF AN INCREASED PULMONARY ARTERY PRESSURE AT 9 WEEKS OF AGE IN MALE SPRAGUE-DAWLEY RATS. METHYL-DNA IMMUNE PRECIPITATION CHIP, GENOME-SCALE MAPPING STUDIES TO SEARCH FOR DIFFERENTIALLY METHYLATED LOCI BETWEEN CONTROL AND EUGR RATS, REVEALED SIGNIFICANT DIFFERENCE IN CYTOSINE METHYLATION BETWEEN EUGR AND CONTROL RATS. EUGR CHANGES THE CYTOSINE METHYLATION AT APPROXIMATELY 500 LOCI IN MALE RATS AT 9 WEEKS OF AGE, PRECEDING THE DEVELOPMENT OF PULMONARY HYPERTENSION AND THESE REPRESENT THE CANDIDATE LOCI FOR MEDIATING THE PATHOGENESIS OF PULMONARY VASCULAR DISEASE THAT OCCURS LATER IN LIFE. GENE ONTOLOGY ANALYSIS ON DIFFERENTIALLY METHYLATED GENES SHOWED THAT HYPERMETHYLATED GENES IN EUGR ARE VASCULAR DEVELOPMENT-ASSOCIATED GENES AND HYPOMETHYLATED GENES IN EUGR ARE LATE-DIFFERENTIATION-ASSOCIATED AND SIGNAL TRANSDUCTION GENES. WE VALIDATED CANDIDATE DYSREGULATED LOCI WITH THE QUANTITATIVE ASSAYS OF CYTOSINE METHYLATION AND GENE EXPRESSIONS. CONCLUSION: THESE RESULTS DEMONSTRATE THAT EPIGENETICS DYSREGULATION IS A STRONG MECHANISM FOR PROPAGATING THE CELLULAR MEMORY OF EARLY POSTNATAL EVENTS, CAUSING CHANGES IN THE EXPRESSION OF GENES AND LONG-TERM SUSCEPTIBILITY TO PULMONARY HYPERTENSION, AND FURTHER PROVIDING A NEW INSIGHT INTO THE PREVENTION AND TREATMENT OF EUGR-RELATED PULMONARY HYPERTENSION. 2014 10 2246 23 EPIGENETIC MODULATION OF INFLAMMATION AND SYNAPTIC PLASTICITY PROMOTES RESILIENCE AGAINST STRESS IN MICE. MAJOR DEPRESSIVE DISORDER IS ASSOCIATED WITH ABNORMALITIES IN THE BRAIN AND THE IMMUNE SYSTEM. CHRONIC STRESS IN ANIMALS SHOWED THAT EPIGENETIC AND INFLAMMATORY MECHANISMS PLAY IMPORTANT ROLES IN MEDIATING RESILIENCE AND SUSCEPTIBILITY TO DEPRESSION. HERE, THROUGH A HIGH-THROUGHPUT SCREENING, WE IDENTIFY TWO PHYTOCHEMICALS, DIHYDROCAFFEIC ACID (DHCA) AND MALVIDIN-3'-O-GLUCOSIDE (MAL-GLUC) THAT ARE EFFECTIVE IN PROMOTING RESILIENCE AGAINST STRESS BY MODULATING BRAIN SYNAPTIC PLASTICITY AND PERIPHERAL INFLAMMATION. DHCA/MAL-GLUC ALSO SIGNIFICANTLY REDUCES DEPRESSION-LIKE PHENOTYPES IN A MOUSE MODEL OF INCREASED SYSTEMIC INFLAMMATION INDUCED BY TRANSPLANTATION OF HEMATOPOIETIC PROGENITOR CELLS FROM STRESS-SUSCEPTIBLE MICE. DHCA REDUCES PRO-INFLAMMATORY INTERLEUKIN 6 (IL-6) GENERATIONS BY INHIBITING DNA METHYLATION AT THE CPG-RICH IL-6 SEQUENCES INTRONS 1 AND 3, WHILE MAL-GLUC MODULATES SYNAPTIC PLASTICITY BY INCREASING HISTONE ACETYLATION OF THE REGULATORY SEQUENCES OF THE RAC1 GENE. PERIPHERAL INFLAMMATION AND SYNAPTIC MALADAPTATION ARE IN LINE WITH NEWLY HYPOTHESIZED CLINICAL INTERVENTION TARGETS FOR DEPRESSION THAT ARE NOT ADDRESSED BY CURRENTLY AVAILABLE ANTIDEPRESSANTS. 2018 11 2442 34 EPIGENETIC STABILITY IN THE ADULT MOUSE CORTEX UNDER CONDITIONS OF PHARMACOLOGICALLY INDUCED HISTONE ACETYLATION. HISTONE ACETYLATION IS CONSIDERED A MAJOR EPIGENETIC PROCESS THAT AFFECTS BRAIN DEVELOPMENT AND SYNAPTIC PLASTICITY, AS WELL AS LEARNING AND MEMORY. THE TRANSCRIPTIONAL EFFECTORS AND MORPHOLOGICAL CHANGES RESPONSIBLE FOR PLASTICITY AS A RESULT OF LONG-TERM MODIFICATIONS TO HISTONE ACETYLATION ARE NOT FULLY UNDERSTOOD. TO THIS END, WE PHARMACOLOGICALLY INHIBITED HISTONE DEACETYLATION USING TRICHOSTATIN A IN ADULT (6-MONTH-OLD) MICE AND FOUND SIGNIFICANT INCREASES IN THE LEVELS OF THE ACETYLATED HISTONE MARKS H3LYS9, H3LYS14 AND H4LYS12. HIGH-RESOLUTION TRANSCRIPTOME ANALYSIS OF DIVERSE BRAIN REGIONS UNCOVERED FEW DIFFERENCES IN GENE EXPRESSION BETWEEN TREATED AND CONTROL ANIMALS, NONE OF WHICH WERE PLASTICITY RELATED. INSTEAD, AFTER INCREASED HISTONE ACETYLATION, WE DETECTED A LARGE NUMBER OF NOVEL TRANSCRIPTIONALLY ACTIVE REGIONS, WHICH CORRESPOND TO LONG NON-CODING RNAS (LNCRNAS). WE ALSO SURPRISINGLY FOUND NO SIGNIFICANT CHANGES IN DENDRITIC SPINE PLASTICITY IN LAYERS 1 AND 2/3 OF THE VISUAL CORTEX USING LONG-TERM IN VIVO TWO-PHOTON IMAGING. OUR RESULTS INDICATE THAT CHRONIC PHARMACOLOGICALLY INDUCED HISTONE ACETYLATION CAN BE DECOUPLED FROM GENE EXPRESSION AND INSTEAD, MAY POTENTIALLY EXERT A POST-TRANSCRIPTIONAL EFFECT THROUGH THE DIFFERENTIAL PRODUCTION OF LNCRNAS. 2016 12 6226 20 THE LINK BETWEEN EPIGENETICS, PAIN SENSITIVITY AND CHRONIC PAIN. INCREASING EVIDENCE SUGGESTS AN ASSOCIATION BETWEEN GENE EXPRESSION AND CLINICAL PAIN. EPIGENETIC MODIFICATIONS ARE THE MAIN MODULATORS OF GENE EXPRESSION OR PROTEIN TRANSLATION IN RESPONSE TO ENVIRONMENTAL STIMULI AND PATHOPHYSIOLOGICAL CONDITIONS. PRECLINICAL AND CLINICAL STUDIES INDICATE THAT EPIGENETIC MODIFICATIONS COULD ALSO IMPACT THE DEVELOPMENT OF PAIN, THE TRANSITION FROM ACUTE TO CHRONIC PAIN, AND THE MAINTENANCE HEREOF. 2022 13 19 38 5-AZACYTYDINE AND RESVERATROL REVERSE SENESCENCE AND AGEING OF ADIPOSE STEM CELLS VIA MODULATION OF MITOCHONDRIAL DYNAMICS AND AUTOPHAGY. OBESITY AND ENDOCRINE DISORDERS HAVE BECOME PREVALENT ISSUES IN THE FIELD OF BOTH HUMAN AND VETERINARY MEDICINE. EQUINE METABOLIC SYNDROME IS A COMPLEX DISORDER INVOLVING ALTERNATION IN METABOLISM AND CHRONIC SYSTEMIC INFLAMMATION. IT HAS BEEN SHOWN THAT UNFAVOURABLE MICROENVIRONMENT OF INFLAMED ADIPOSE TISSUE NEGATIVELY AFFECTS ADIPOSE STEM CELL POPULATION (ASC) RESIDING WITHIN, MARKEDLY LIMITING THEIR THERAPEUTIC POTENTIAL. ASCS(EMS) ARE CHARACTERIZED BY INCREASED SENESCENCE APOPTOSIS, EXCESSIVE ACCUMULATION OF REACTIVE OXYGEN SPECIES (ROS), MITOCHONDRIA DETERIORATION AND "AUTOPHAGIC FLUX." THE AIM OF THE PRESENT STUDY WAS TO EVALUATE WHETHER TREATMENT OF ASCS(EMS) WITH A COMBINATION OF 5-AZACYTYDINE (AZA) AND RESVERATROL (RES) WOULD REVERSE AGED PHENOTYPE OF THESE CELLS. FOR THIS REASON, WE PERFORMED THE FOLLOWING ANALYZES: MOLECULAR BIOLOGY (RT-PCR), MICROSCOPIC (IMMUNOFLUORESCENCE, TEM) AND FLOW CYTOMETRY (JC-1, ROS, KI67). WE EVALUATED THE MITOCHONDRIAL STATUS, DYNAMICS AND CLEARANCE AS WELL AS AUTOPHAGIC PATHWAYS. FURTHERMORE, WE INVESTIGATED EPIGENETIC ALTERNATIONS IN TREATED CELLS BY MEASURING THE EXPRESSION OF TET GENES AND ANALYSIS OF DNA METHYLATION STATUS. WE HAVE DEMONSTRATED THAT AZA/RES TREATMENT OF ASCS(EMS) IS ABLE TO REJUVENATE THESE CELLS BY MODULATING MITOCHONDRIAL DYNAMICS, IN PARTICULAR BY PROMOTING MITOCHONDRIAL FUSION OVER FISSION. AFTER AZA/RES TREATMENT, ASCS(EMS) WERE CHARACTERIZED BY INCREASED PROLIFERATION RATE, DECREASED APOPTOSIS AND SENESCENCE AND LOWER ROS ACCUMULATION. OUR FINDINGS OFFER A NOVEL APPROACH AND POTENTIAL TARGETS FOR THE BENEFICIAL EFFECTS OF AZA/RES IN AMELIORATING STEM CELL DYSFUNCTIONS. 2019 14 761 37 CATEGORIZING THE CHARACTERISTICS OF HUMAN CARCINOGENS: A NEED FOR SPECIFICITY. THE INTERNATIONAL AGENCY FOR RESEARCH ON CANCER (IARC) HAS RECENTLY PROPOSED EMPLOYING "TEN KEY CHARACTERISTICS OF HUMAN CARCINOGENS" (TKCS) TO DETERMINE THE POTENTIAL OF AGENTS FOR HARMFUL EFFECTS. THE TKCS SEEM LIKELY TO CONFUSE THE UNSATISFACTORY CORRELATION FROM TESTING REGIMES THAT HAVE IGNORED THE DIFFERENCES EVIDENT WHEN CELLULAR CHANGES ARE COMPARED IN SHORT AND LONG-LIVED SPECIES, WITH THEIR VERY DIFFERENT STEM CELL AND SOMATIC CELL PHYLOGENIES. THE PROPOSED CHARACTERISTICS ARE SO BROAD THAT THEIR USE WILL LEAD TO AN INCREASE IN THE CURRENT UNACCEPTABLY HIGH RATE OF FALSE POSITIVES. IT COULD BE AN INFORMATIVE EXPERIMENT TO TAKE WELL-ESTABLISHED APPROVED THERAPEUTICS WITH WELL-KNOWN HUMAN SAFETY PROFILES AND TEST THEM AGAINST THIS NEW TKC PARADIGM. CANCERS ARE INITIATED AND DRIVEN BY HERITABLE AND TRANSIENT CHANGES IN GENE EXPRESSION, EXPAND CLONALLY, AND PROGRESS VIA ADDITIONAL ASSOCIATED ACQUIRED MUTATIONS AND EPIGENETIC ALTERATIONS THAT PROVIDE CELLS WITH AN EVOLUTIONARY ADVANTAGE. THE GENOTOXICITY TESTING PROTOCOLS CURRENTLY EMPLOYED AND REQUIRED BY REGULATION, EMPHASIZE TESTING FOR THE MUTATIONAL POTENTIAL OF THE TEST AGENT. TWO-YEAR, CHRONIC RODENT CANCER BIOASSAYS ARE INTENDED TO TEST FOR THE ENTIRE SPECTRUM OF CARCINOGENIC TRANSFORMATION. THE USE OF CYTOTOXIC DOSES CAUSING INCREASED, SUSTAINED CELL PROLIFERATION THAT FACILITATES ACCUMULATED GENETIC DAMAGE LEADS TO A HIGH FALSE-POSITIVE RATE OF TUMOR INDUCTION. CURRENT CANCER HAZARD ASSESSMENT PROTOCOLS AND WEIGHT-OF-THE-EVIDENCE ANALYSIS OF AGENT-SPECIFIC CANCER RISK ALIGN POORLY WITH THE PATHOGENESIS OF HUMAN CARCINOMA AND SO NEED MODERNIZATION AND IMPROVEMENT IN WAYS SUGGESTED HERE. 2021 15 1362 27 DEVELOPMENTAL EPIGENETIC PROGRAMMING OF ADULT GERM CELL DEATH DISEASE: POLYCOMB PROTEIN EZH2-MIR-101 PATHWAY. AIM: THE DEVELOPMENTAL ORIGIN OF HEALTH AND DISEASE REFERS TO THE CONCEPT THAT EARLY EXPOSURE TO TOXICANTS OR NUTRITIONAL IMBALANCES DURING PERINATAL LIFE INDUCES CHANGES THAT ENHANCE THE RISK OF DEVELOPING NONCOMMUNICABLE DISEASES IN ADULTHOOD. PATIENTS/MATERIALS & METHODS: AN EXPERIMENTAL MODEL WITH AN ADULT CHRONIC GERM CELL DEATH PHENOTYPE RESULTING FROM EXPOSURE TO A XENOESTROGEN WAS USED. RESULTS: A RECIPROCAL NEGATIVE FEEDBACK LOOP INVOLVING DECREASED EZH2 PROTEIN LEVEL AND INCREASED MIR-101 EXPRESSION WAS IDENTIFIED. IN VITRO AND IN VIVO KNOCKDOWN OF EZH2 INDUCED AN APOPTOTIC PROCESS IN GERM CELLS THROUGH INCREASED LEVELS OF APOPTOTIC FACTORS (BIM AND BAD) AND DNA REPAIR ALTERATION VIA TOPOISOMERASE 2B DEREGULATION. THE INCREASED MIR-101 LEVELS WERE OBSERVED IN THE ANIMAL BLOOD, MEANING THAT MIR-101 MAY BE A PART OF A CIRCULATING MARK OF GERM CELL DEATH. CONCLUSION: MIR-101-EZH2 PATHWAY DEREGULATION COULD REPRESENT A NOVEL PATHOPHYSIOLOGICAL EPIGENETIC BASIS FOR ADULT GERM CELL DISEASE WITH ENVIRONMENTAL AND DEVELOPMENTAL ORIGINS. 2016 16 2072 46 EPIGENETIC CONVERSION OF HUMAN ADULT BONE MESODERMAL STROMAL CELLS INTO NEUROECTODERMAL CELL TYPES FOR REPLACEMENT THERAPY OF NEURODEGENERATIVE DISORDERS. TISSUE-SPECIFIC STEM CELLS, SUCH AS BONE MARROW-DERIVED MESODERMAL STROMAL CELLS (MSCS), ARE THOUGHT TO BE LINEAGE RESTRICTED AND, THEREFORE, COULD ONLY BE DIFFERENTIATED INTO CELL TYPES OF THE TISSUE OF ORIGIN. SEVERAL RECENT STUDIES, HOWEVER, SUGGEST THAT THESE TYPES OF STEM CELLS MIGHT BE ABLE TO BREAK BARRIERS OF GERM LAYER COMMITMENT AND DIFFERENTIATE IN VITRO AND/OR IN VIVO INTO CELLS OF DIFFERENT TISSUES, SUCH AS NEUROECTODERMAL CELL TYPES. RECENTLY, PROTOCOLS FOR HIGH-YIELD GENERATION OF UNDIFFERENTIATED NEURAL STEM CELL (NSC)-LIKE CELLS FROM MSCS OF PRIMATE AND HUMAN ORIGIN WERE REPORTED. UNDIFFERENTIATED NSCS ARE COMMONLY USED AND ARE MORE SUITABLE FOR NEUROTRANSPLANTATION COMPARED WITH FULLY DIFFERENTIATED NEURAL CELLS, AS DIFFERENTIATED NEURAL CELLS ARE WELL KNOWN TO POORLY SURVIVE DETACHMENT AND SUBSEQUENT TRANSPLANTATION PROCEDURES. THESE HUMAN MSC-DERIVED NSC-LIKE CELLS (MSC-NSCS) GROW IN NEUROSPHERE-LIKE STRUCTURES AND EXPRESS HIGH LEVELS OF EARLY NEUROECTODERMAL MARKERS, BUT LOSE CHARACTERISTICS OF MSCS. IN THE PRESENCE OF SELECTED GROWTH FACTORS, HUMAN MSC-NSCS CAN BE DIFFERENTIATED INTO THE THREE MAIN NEURAL PHENOTYPES: ASTROGLIA, OLIGODENDROGLIA AND NEURONS. COMPARED WITH DIRECT DIFFERENTIATION OF HUMAN MSCS INTO MATURE NEURAL CELLS, THE CONVERSION STEP SEEMS TO BE ESSENTIAL TO GENERATE MATURE FUNCTIONAL NEUROECTODERMAL CELLS. THIS REVIEW DESCRIBES THE TECHNIQUES FOR THE CONVERSION OF HUMAN MSCS INTO NSCS AND SUMMARISES THE DATA ON EPIGENETIC CONVERSION OF HUMAN MSCS INTO IMMATURE NEUROECTODERMAL CELLS. THESE CELLS PROVIDE A POWERFUL TOOL FOR INVESTIGATING THE MOLECULAR MECHANISMS OF NEURAL DIFFERENTIATION, AND MIGHT SERVE AS AN AUTOLOGOUS CELL SOURCE TO TREAT ACUTE AND CHRONIC NEURODEGENERATIVE DISEASES. 2006 17 5614 37 SAFETY AND EFFICACY OF EPIGENETICALLY CONVERTED HUMAN FIBROBLASTS INTO INSULIN-SECRETING CELLS: A PRECLINICAL STUDY. TYPE 1 DIABETES MELLITUS (T1DM) IS A CHRONIC DISEASE THAT LEADS TO LOSS OF INSULIN SECRETING BETA-CELLS, CAUSING HIGH LEVELS OF BLOOD GLUCOSE. EXOGENOUS INSULIN ADMINISTRATION IS NOT SUFFICIENT TO MIMIC THE NORMAL FUNCTION OF BETA-CELLS AND, CONSEQUENTLY, DIABETES MELLITUS OFTEN PROGRESSES AND CAN LEAD TO MAJOR CHRONIC COMPLICATIONS AND MORBIDITY. THE PHYSIOLOGICAL CONTROL OF GLUCOSE LEVELS CAN ONLY BE RESTORED BY REPLACING THE BETA-CELL MASS.WE RECENTLY DEVELOPED A NEW STRATEGY THAT ALLOWS FOR EPIGENETIC CONVERSION OF DERMAL FIBROBLASTS INTO INSULIN-SECRETING CELLS (EPICC), USING A BRIEF EXPOSURE TO THE DEMETHYLATING AGENT 5-AZA-CYTIDINE (5-AZA-CR), FOLLOWED BY A PANCREATIC INDUCTION PROTOCOL. THIS METHOD HAS NOTABLE ADVANTAGES COMPARED TO THE ALTERNATIVE AVAILABLE PROCEDURES AND MAY REPRESENT A PROMISING TOOL FOR CLINICAL TRANSLATION AS A THERAPY FOR T1DM. HOWEVER, A THOUGHT EVALUATION OF ITS THERAPEUTIC SAFETY AND EFFICACY IS MANDATORY TO SUPPORT PRECLINICAL STUDIES BASED ON EPICC TREATMENT.WE HERE REPORT THE DATA OBTAINED USING HUMAN FIBROBLASTS ISOLATED FROM DIABETIC AND HEALTHY INDIVIDUALS, BELONGING THE TWO GENDERS. EPICC WERE INJECTED INTO 650 DIABETIC SEVERE COMBINED IMMUNODEFICIENCY (SCID) MICE AND DEMONSTRATED TO BE ABLE TO RESTORE AND MAINTAIN GLYCEMIC LEVELS WITHIN THE PHYSIOLOGICAL RANGE. CELLS HAD THE ABILITY TO SELF-REGULATE AND NOT TO CAUSE HYPOGLYCEMIA, WHEN TRANSPLANTED IN HEALTHY ANIMALS. EFFICACY TESTS SHOWED THAT EPICC SUCCESSFULLY RE-ESTABLISHED NORMOGLYCEMIA IN DIABETIC MICE, USING A DOSE RANGE THAT APPEARED CLINICALLY RELEVANT TO THE CONCENTRATION 0.6 X 10(6) EPICC. NECROPSY AND HISTOPATHOLOGICAL INVESTIGATIONS DEMONSTRATED THE ABSENCE OF MALIGNANT TRANSFORMATION AND CELL MIGRATION TO ORGANS AND LYMPH NODES.THE PRESENT PRECLINICAL STUDY DEMONSTRATES SAFETY AND EFFICACY OF HUMAN EPICC IN DIABETIC MICE AND SUPPORTS THE USE OF EPIGENETIC CONVERTED CELLS FOR REGENERATIVE MEDICINE OF DIABETES MELLITUS. 2018 18 1117 31 COMPARATIVE AND EXPERIMENTAL STUDIES ON THE GENES ALTERED BY CHRONIC HYPOXIA IN HUMAN BRAIN MICROENDOTHELIAL CELLS. BACKGROUND : HYPOXIA INDUCIBLE FACTOR 1 ALPHA (HIF1A) IS A MASTER REGULATOR OF ACUTE HYPOXIA; HOWEVER, WITH CHRONIC HYPOXIA, HIF1A LEVELS RETURN TO THE NORMOXIC LEVELS. IMPORTANTLY, THE GENES THAT ARE INVOLVED IN THE CELL SURVIVAL AND VIABILITY UNDER CHRONIC HYPOXIA ARE NOT KNOWN. THEREFORE, WE TESTED THE HYPOTHESIS THAT CHRONIC HYPOXIA LEADS TO THE UPREGULATION OF A CORE GROUP OF GENES WITH ASSOCIATED CHANGES IN THE PROMOTER DNA METHYLATION THAT MEDIATES THE CELL SURVIVAL UNDER HYPOXIA. RESULTS : WE EXAMINED THE EFFECT OF CHRONIC HYPOXIA (3 DAYS; 0.5% OXYGEN) ON HUMAN BRAIN MICRO ENDOTHELIAL CELLS (HBMEC) VIABILITY AND APOPTOSIS. HYPOXIA CAUSED A SIGNIFICANT REDUCTION IN CELL VIABILITY AND AN INCREASE IN APOPTOSIS. NEXT, WE EXAMINED CHRONIC HYPOXIA ASSOCIATED CHANGES IN TRANSCRIPTOME AND GENOME-WIDE PROMOTER METHYLATION. THE DATA OBTAINED WAS COMPARED WITH 16 OTHER MICROARRAY STUDIES ON CHRONIC HYPOXIA. NINE GENES WERE ALTERED IN RESPONSE TO CHRONIC HYPOXIA IN ALL 17 STUDIES. INTERESTINGLY, HIF1A WAS NOT ALTERED WITH CHRONIC HYPOXIA IN ANY OF THE STUDIES. FURTHERMORE, WE COMPARED OUR DATA TO THREE OTHER STUDIES THAT IDENTIFIED HIF-RESPONSIVE GENES BY VARIOUS APPROACHES. ONLY TWO GENES WERE FOUND TO BE HIF DEPENDENT. WE SILENCED EACH OF THESE 9 GENES USING CRISPR/CAS9 SYSTEM. DOWNREGULATION OF EGLN3 SIGNIFICANTLY INCREASED THE CELL DEATH UNDER CHRONIC HYPOXIA, WHEREAS DOWNREGULATION OF ERO1L, ENO2, ADRENOMEDULLIN, AND SPAG4 REDUCED THE CELL DEATH UNDER HYPOXIA. CONCLUSIONS : WE PROVIDE A CORE GROUP OF GENES THAT REGULATES CELLULAR ACCLIMATIZATION UNDER CHRONIC HYPOXIC STRESS, AND MOST OF THEM ARE HIF INDEPENDENT. 2017 19 4 31 "MIX OF MICS"- PHENOTYPIC AND BIOLOGICAL HETEROGENEITY OF "MULTIPOTENT" MUSCLE INTERSTITIAL CELLS (MICS). THE CAPACITY OF ADULT SKELETAL MUSCLE FOR REGENERATION APPEARS TO BE LIMITED, WITH PROGRESSIVE IMPAIRMENT IN REPAIR EFFICIENCY OF INJURED MUSCLES OBSERVED IN CHRONIC MUSCULAR DISORDERS AND DURING AGING. WHILE SATELLITE CELLS, THE COMMITTED ADULT MUSCLE STEM CELLS, ARE THE MAIN DIRECT CELL SOURCE SUPPORTING THE REGENERATIVE POTENTIAL OF ADULT SKELETAL MUSCLES, THE CHARACTERIZATION OF THE CELL TYPES AND SIGNALS THAT CONSTITUTE THE FUNCTIONAL "NICHE" OF SATELLITE CELLS IS CURRENTLY THE OBJECT OF INTENSE INVESTIGATION. RECENT STUDIES HAVE IDENTIFIED A FUNCTIONAL RELATIONSHIP BETWEEN SATELLITE CELLS AND VARIOUS CELL TYPES LOCATED IN KEY ANATOMICAL POSITION, SUCH AS THE INTERSTITIUM OF SKELETAL MUSCLES. THIS HETEROGENEOUS POPULATION OF MUSCLE INTERSTITIAL CELLS (MICS) APPEARS TO RETAIN AN INTRINSIC MULTIPOTENCY WITHIN THE MESODERMAL LINEAGE, AND THEIR DIRECT OR INDIRECT CONTRIBUTION TO MYOFIBER TURNOVER, REPAIR AND DEGENERATION HAS BEEN SUGGESTED BY MANY STUDIES THAT WILL BE REVIEWED HERE. GIVEN THE EXISTING GAP OF KNOWLEDGE ON LINEAGE IDENTITY AND FUNCTIONAL PROPERTIES OF MICS, THEIR DETAILED CHARACTERIZATION AT THE SINGLE CELL LEVEL HOLDS THE PROMISE TO PROVIDE KEY INSIGHT INTO THE COMPOSITION OF THIS HETEROGENEOUS POPULATION AND THE DYNAMIC TRANSITION THROUGH DISTINCT SUB-POPULATIONS IN HEALTHY, DISEASED AND AGING MUSCLES. THIS REVIEW PROVIDES AN OVERVIEW OF THE RESULTS OF VARIOUS STUDIES DESCRIBING THE PHENOTYPE AND THE FUNCTION OF CELLS ISOLATED FROM SKELETAL MUSCLE INTERSTITIUM, AND DISCUSSES THE IMPORTANCE OF SINGLE CELL TRANSCRIPTION PROFILING IN ORDER TO DECIPHER THE FUNCTIONAL AND PHENOTYPICAL HETEROGENEITY OF MUSCLE INTERSTITIAL CELLS (MICS). 2012 20 4875 39 OVEREXPRESSION OF AKT1 ENHANCES ADIPOGENESIS AND LEADS TO LIPOMA FORMATION IN ZEBRAFISH. BACKGROUND: OBESITY IS A COMPLEX, MULTIFACTORIAL DISORDER INFLUENCED BY THE INTERACTION OF GENETIC, EPIGENETIC, AND ENVIRONMENTAL FACTORS. OBESITY INCREASES THE RISK OF CONTRACTING MANY CHRONIC DISEASES OR METABOLIC SYNDROME. RESEARCHERS HAVE ESTABLISHED SEVERAL MAMMALIAN MODELS OF OBESITY TO STUDY ITS UNDERLYING MECHANISM. HOWEVER, A LOWER VERTEBRATE MODEL FOR CONVENIENTLY PERFORMING DRUG SCREENING AGAINST OBESITY REMAINS ELUSIVE. THE SPECIFIC AIM OF THIS STUDY WAS TO CREATE A ZEBRAFISH OBESITY MODEL BY OVER EXPRESSING THE INSULIN SIGNALING HUB OF THE AKT1 GENE. METHODOLOGY/PRINCIPAL FINDINGS: SKIN ONCOGENIC TRANSFORMATION SCREENING SHOWS THAT A STABLE ZEBRAFISH TRANSGENIC OF TG(KRT4HSA.MYRAKT1)(CY18) DISPLAYS SEVERELY OBESE PHENOTYPES AT THE ADULT STAGE. IN TG(KRT4:HSA.MYRAKT1)(CY18), THE EXPRESSION OF EXOGENOUS HUMAN CONSTITUTIVELY ACTIVE AKT1 (MYRAKT1) CAN ACTIVATE ENDOGENOUS DOWNSTREAM TARGETS OF MTOR, GSK-3ALPHA/BETA, AND 70S6K. DURING THE EMBRYONIC TO LARVAL TRANSITORY PHASE, THE SPECIFIC OVER EXPRESSION OF MYRAKT1 IN SKIN CAN PROMOTE HYPERTROPHIC AND HYPERPLASTIC GROWTH. FROM 21 HOUR POST-FERTILIZATION (HPF) ONWARDS, MYRAKT1 TRANSGENE WAS ECTOPICALLY EXPRESSED IN SEVERAL MESENCHYMAL DERIVED TISSUES. THIS MAY BE THE RESULT OF THE INTEGRATION POSITION EFFECT. TG(KRT4:HSA.MYRAKT1)(CY18) CAUSED A RAPID INCREASE OF BODY WEIGHT, HYPERPLASTIC GROWTH OF ADIPOCYTES, ABNORMAL ACCUMULATION OF FAT TISSUES, AND BLOOD GLUCOSE INTOLERANCE AT THE ADULT STAGE. REAL-TIME RT-PCR ANALYSIS SHOWED THE MAJORITY OF KEY GENES ON REGULATING ADIPOGENESIS, ADIPOCYTOKINE, AND INFLAMMATION ARE HIGHLY UPREGULATED IN TG(KRT4:HSA.MYRAKT1)(CY18). IN CONTRAST, THE MYOGENESIS- AND SKELETOGENESIS-RELATED GENE TRANSCRIPTS ARE SIGNIFICANTLY DOWNREGULATED IN TG(KRT4:HSA.MYRAKT1)(CY18), SUGGESTING THAT EXCESS ADIPOCYTE DIFFERENTIATION OCCURS AT THE EXPENSE OF OTHER MESENCHYMAL DERIVED TISSUES. CONCLUSION/SIGNIFICANCE: COLLECTIVELY, THE FINDINGS OF THIS STUDY PROVIDE DIRECT EVIDENCE THAT AKT1 SIGNALING PLAYS AN IMPORTANT ROLE IN BALANCING NORMAL LEVELS OF FAT TISSUE IN VIVO. THE OBESE ZEBRAFISH EXAMINED IN THIS STUDY COULD BE A NEW POWERFUL MODEL TO SCREEN NOVEL DRUGS FOR THE TREATMENT OF HUMAN OBESITY. 2012