1 202 92 ACTIVATION INDUCED CYTIDINE DEAMINASE: AN OLD FRIEND WITH NEW FACES. ACTIVATION INDUCED CYTIDINE DEAMINASE (AID) PROTEIN IS A MEMBER OF APOBEC FAMILY. AID CONVERTS CYTIDINE TO URACIL, WHICH IS A KEY STEP FOR SOMATIC HYPERMUTATION (SHM) AND CLASS SWITCH RECOMBINATION (CSR). AID ALSO PLAYS CRITICAL ROLES IN B CELL PRECURSOR STAGES, REMOVING POLYREACTIVE B CELLS FROM IMMUNE REPERTOIRE. SINCE THE MAIN FUNCTION OF AID IS INDUCING POINT MUTATIONS, DYSREGULATION CAN LEAD TO INCREASED MUTATION LOAD, TRANSLOCATIONS, DISTURBED GENOMIC INTEGRITY, AND LYMPHOMAGENESIS. AS SUCH, EXPRESSION OF AID AS WELL AS ITS FUNCTION IS CONTROLLED STRICTLY AT VARIOUS MOLECULAR STEPS. OTHER MEMBERS OF THE APOBEC FAMILY ALSO PLAY CRUCIAL ROLES DURING CARCINOGENESIS. CONSIDERING ALL THESE FUNCTIONS, AID REPRESENTS A BRIDGE, LINKING CHRONIC INFLAMMATION TO CARCINOGENESIS AND IMMUNE DEFICIENCIES TO AUTOIMMUNE MANIFESTATIONS. 2022 2 1176 25 CONTROL OF APOBEC3B INDUCTION AND CCCDNA DECAY BY NF-KAPPAB AND MIR-138-5P. BACKGROUND & AIMS: IMMUNE-MEDIATED INDUCTION OF CYTIDINE DEAMINASE APOBEC3B (A3B) EXPRESSION LEADS TO HBV COVALENTLY CLOSED CIRCULAR DNA (CCCDNA) DECAY. HERE, WE AIMED TO DECIPHER THE SIGNALLING PATHWAY(S) AND REGULATORY MECHANISM(S) INVOLVED IN A3B INDUCTION AND RELATED HBV CONTROL. METHODS: DIFFERENTIATED HEPARG CELLS (DHEPARG) KNOCKED-DOWN FOR NF-KAPPAB SIGNALLING COMPONENTS, TRANSFECTED WITH SIRNA OR MICRO RNAS (MIRNA), AND PRIMARY HUMAN HEPATOCYTES +/- HBV OR HBVDELTAX OR HBV-RFP, WERE TREATED WITH LYMPHOTOXIN BETA RECEPTOR (LTBETAR)-AGONIST (BS1). THE BIOLOGICAL OUTCOMES WERE ANALYSED BY REVERSE TRANSCRIPTASE-QPCR, IMMUNOBLOTTING, LUCIFERASE ACTIVITY, CHROMATIN IMMUNE PRECIPITATION, ELECTROPHORETIC MOBILITY-SHIFT ASSAY, TARGETED-BISULFITE-, MIRNA-, RNA-, GENOME-SEQUENCING, AND MASS-SPECTROMETRY. RESULTS: WE FOUND THAT CANONICAL AND NON-CANONICAL NF-KAPPAB SIGNALLING PATHWAYS ARE MANDATORY FOR A3B INDUCTION AND ANTI-HBV EFFECTS. THE DEGREE OF IMMUNE-MEDIATED A3B PRODUCTION IS INDEPENDENT OF A3B PROMOTER DEMETHYLATION BUT IS CONTROLLED POST-TRANSCRIPTIONALLY BY THE MIRNA 138-5P EXPRESSION (HSA-MIR-138-5P), PROMOTING A3B MRNA DECAY. HSA-MIR-138-5P OVER-EXPRESSION REDUCED A3B LEVELS AND ITS ANTIVIRAL EFFECTS. OF NOTE, ESTABLISHED INFECTION INHIBITED BS1-INDUCED A3B EXPRESSION THROUGH EPIGENETIC MODULATION OF A3B PROMOTER. TWELVE DAYS OF TREATMENT WITH A LTBETAR-SPECIFIC AGONIST BS1 IS SUFFICIENT TO REDUCE THE CCCDNA POOL BY 80% WITHOUT INDUCING SIGNIFICANT DAMAGES TO A SUBSET OF CANCER-RELATED HOST GENES. INTERESTINGLY, THE A3B-MEDIATED EFFECT ON HBV IS INDEPENDENT OF THE TRANSCRIPTIONAL ACTIVITY OF CCCDNA AS WELL AS ON RCDNA SYNTHESIS. CONCLUSIONS: ALTOGETHER, A3B REPRESENTS THE ONLY DESCRIBED ENZYME TO TARGET BOTH TRANSCRIPTIONALLY ACTIVE AND INACTIVE CCCDNA. THUS, INHIBITING HSA-MIR-138-5P EXPRESSION SHOULD BE CONSIDERED IN THE COMBINATORIAL DESIGN OF NEW THERAPIES AGAINST HBV, ESPECIALLY IN THE CONTEXT OF IMMUNE-MEDIATED A3B INDUCTION. LAY SUMMARY: IMMUNE-MEDIATED INDUCTION OF CYTIDINE DEAMINASE APOBEC3B IS TRANSCRIPTIONALLY REGULATED BY NF-KAPPAB SIGNALLING AND POST-TRANSCRIPTIONALLY DOWNREGULATED BY HSA-MIR-138-5P EXPRESSION, LEADING TO CCCDNA DECAY. TIMELY CONTROLLED APOBEC3B-MEDIATED CCCDNA DECAY OCCURS INDEPENDENTLY OF CCCDNA TRANSCRIPTIONAL ACTIVITY AND WITHOUT DAMAGE TO A SUBSET OF CANCER-RELATED GENES. THUS, APOBEC3B-MEDIATED CCCDNA DECAY COULD OFFER AN EFFICIENT THERAPEUTIC ALTERNATIVE TO TARGET HEPATITIS B VIRUS CHRONIC INFECTION. 2021 3 1691 22 DUCTAL CELLS OF MINOR SALIVARY GLANDS IN SJOGREN'S SYNDROME EXPRESS LINE-1 ORF2P AND APOBEC3B. BACKGROUND: TYPE I INTERFERON ACTIVATION IS A HALLMARK EVENT IN SJOGREN'S SYNDROME. L1 RETROELEMENTS STIMULATE PLASMACYTOID DENDRITIC CELLS, ACTIVATING THE TYPE I INTERFERONS, AND ARE REGULATED BY VARIOUS MECHANISMS, INCLUDING THE APOBEC3 DEAMINASES. AS L1S ARE POTENTIAL TRIGGER FACTORS IN AUTOIMMUNITY, WE AIMED TO INVESTIGATE THE IMMUNOHISTOCHEMICAL LOCALIZATION OF L1 ORF2P AND ITS INHIBITOR APOBEC3B PROTEIN IN MINOR SALIVARY GLANDS OF SJOGREN'S SYNDROME PATIENTS. METHODS: TWENTY MINOR SALIVARY GLAND-TISSUE SAMPLES FROM 20 SJOGREN'S SYNDROME PATIENTS, CLASSIFIED ACCORDING TO TARPLEY'S HISTOLOGICAL CRITERIA, AND 10 CONTROLS WERE EVALUATED FOR L1 ORF2P AND APOBEC3B EXPRESSION VIA IMMUNOHISTOCHEMISTRY. RESULTS: L1 ORF2P WAS EXPRESSED IN 17/20 SS PATIENTS AND ALL CONTROLS. APOBEC3B EXPRESSION WAS OBSERVED IN 15/20 SJOGREN'S SYNDROME PATIENTS, 5/5 CHRONIC SIALADENITIS, AND 3/5 NORMAL MINOR SALIVARY GLANDS. BOTH ANTIBODIES STAINED THE CYTOPLASM OF THE DUCTAL EPITHELIAL CELLS. NEGATIVE STAINING WAS OBSERVED IN THE ACINAR CELLS. L1 ORF2P-POSITIVE IMMUNOSTAINING WAS SIGNIFICANTLY LOWER IN TARPLEY IV SJOGREN'S SYNDROME PATIENTS THAN CONTROLS (P = .039), AND APOBEC3B-POSITIVE STAINING WAS SIGNIFICANTLY LOWER IN TARPLEY I COMPARED TO TARPLEY II SJOGREN'S SYNDROME PATIENTS (P = .008) AND CONTROLS (P = .035). CONCLUSIONS: L1 ORF2P AND APOBEC3B ARE EXPRESSED IN THE DUCTAL EPITHELIAL CELLS OF MINOR SALIVARY GLANDS THAT ARE AMONG THE KEY TARGETS IN SJOGREN'S SYNDROME. L1 ORF2P EXPRESSION MAY PROMOTE THE L1 ABILITY TO ACT AS AN INTRINSIC ANTIGEN IN SJOGREN'S SYNDROME. THE POTENTIAL FUTURE USE OF L1 ORF2-REVERSE TRANSCRIPTASE INHIBITORS IN AUTOIMMUNITY SUPPORTS FURTHER INVESTIGATION OF L1 EPIGENETIC REGULATION BY APOBEC3 ENZYMES. 2018 4 1775 28 EBV IN T-/NK-CELL TUMORIGENESIS. EPSTEIN-BARR VIRUS (EBV), WHICH IS ASSOCIATED WITH B-CELL PROLIFERATIVE DISORDERS, ALSO TRANSFORMS T- OR NATURAL KILLER (NK)-LINEAGE CELLS AND HAS BEEN CONNECTED WITH VARIOUS T- OR NK (T/NK)-CELL MALIGNANCIES, SUCH AS EXTRANODAL NK/T-CELL LYMPHOMA-NASAL TYPE AND AGGRESSIVE NK-CELL LEUKEMIA. CHRONIC ACTIVE EBV (CAEBV) DISEASE , WHICH OCCURS MOST OFTEN IN CHILDREN AND YOUNG ADULTS IN EAST ASIA, IS AN EBV-ASSOCIATED T-/NK-CELL LYMPHOPROLIFERATIVE DISEASE. PATIENTS WITH CAEBV OFTEN PROGRESS TO OVERT LYMPHOMA OR LEUKEMIA OVER A LONG-TERM CLINICAL COURSE. EBV'S TRANSFORMING CAPACITY IN B CELLS IS WELL CHARACTERIZED, BUT THE MOLECULAR PATHOGENESIS OF CLONAL EXPANSION CAUSED BY EBV IN T/NK CELLS HAS NOT YET BEEN CLARIFIED. IN THE PRIMARY INFECTION, EBV INFECTS B CELLS AND EPITHELIAL CELLS AND MAY ALSO INFECT SOME T/NK CELLS. IN SOME INDIVIDUALS, BECAUSE OF POOR PRESENTATION BY SPECIFIC HUMAN LEUKOCYTE ANTIGENS OR THE GENETIC BACKGROUND, EBV-INFECTED T/NK CELLS EVADE HOST IMMUNITY AND SURVIVE. OCCASIONALLY, WITH THE HELP OF VIRAL ONCOGENES, EBV-ASSOCIATED T/NK LYMPHOPROLIFERATIVE DISEASES, SUCH AS CAEBV, MAY DEVELOP. THE SUBSEQUENT ACCUMULATION OF GENETIC MUTATIONS AND/OR EPIGENETIC MODIFICATIONS IN DRIVER GENES, SUCH AS DDX3X AND TP53, MAY LEAD TO OVERT LYMPHOMA AND LEUKEMIA. ACTIVATION-INDUCED CYTIDINE DEAMINASE AND THE APOBEC3 FAMILY, DRIVEN BY EBV INFECTION, MAY INDUCE CHROMOSOMAL RECOMBINATION AND SOMATIC MUTATIONS. 2018 5 5597 16 ROLES OF MIR-432 AND CIRC_0000418 IN MEDIATING THE ANTI-DEPRESSANT ACTION OF ADAR1. ADENOSINE DEAMINASE ACTING ON RNA1 (ADAR1) IS A NEWLY DISCOVERED EPIGENETIC MOLECULE MARKER THAT IS SENSITIVE TO ENVIRONMENTAL STRESSORS. A RECENT STUDY HAS DEMONSTRATED THAT ADAR1 AFFECTS BDNF EXPRESSION VIA MIR-432 AND IS INVOLVED IN ANTIDEPRESSANT ACTION. HOWEVER, THE DETAILED MOLECULAR MECHANISM IS STILL UNCLEAR. WE HAVE UNCOVERED A NEW MOLECULAR MECHANISM SHOWING THE INVOLVEMENT OF MIR-432 AND CIRC_0000418 IN MEDIATING THE ANTIDEPRESSANT ACTION OF ADAR1. WE DEMONSTRATE THAT THE ADAR1 INDUCER (IFN-GAMMA) ALLEVIATES THE DEPRESSIVE-LIKE BEHAVIORS OF BALB/C MICE TREATED WITH CHRONIC UNPREDICTABLE STRESS (CUS) EXPOSURE. MOREOVER, BOTH IN VIVO AND IN VITRO STUDIES SHOW THAT ADAR1 DIFFERENTLY IMPACTS MIR-432 AND CIRC_0000418 EXPRESSIONS. FURTHERMORE, THE IN VITRO RESULTS DEMONSTRATE THAT CIRC_0000418 OPPOSITELY AFFECTS BDNF EXPRESSION. TOGETHER, OUR RESULTS INDICATE THAT ADAR1 AFFECTS CUS-INDUCED DEPRESSIVE-LIKE BEHAVIOR AND BDNF EXPRESSION BY ACTING ON MIR-432 AND CIRC_0000418. ELUCIDATION OF THIS NEW MOLECULAR MECHANISM WILL NOT ONLY PROVIDE INSIGHTS INTO FURTHER UNDERSTANDING THE IMPORTANT ROLE OF ADAR1 IN STRESS-INDUCED DEPRESSIVE-LIKE BEHAVIOR BUT ALSO SUGGEST A POTENTIAL THERAPEUTIC STRATEGY FOR DEVELOPING NOVEL ANTI-DEPRESSIVE DRUGS. 2021 6 6004 27 THE AID DILEMMA: INFECTION, OR CANCER? ACTIVATION-INDUCED CYTIDINE DEAMINASE (AID), WHICH IS BOTH ESSENTIAL AND SUFFICIENT FOR FORMING ANTIBODY MEMORY, IS ALSO LINKED TO TUMORIGENESIS. AID IS FOUND IN MANY B LYMPHOMAS, IN MYELOID LEUKEMIA, AND IN PATHOGEN-INDUCED TUMORS SUCH AS ADULT T CELL LEUKEMIA. ALTHOUGH THERE IS NO SOLID EVIDENCE THAT AID CAUSES HUMAN TUMORS, AID-TRANSGENIC AND AID-DEFICIENT MOUSE MODELS INDICATE THAT AID IS BOTH SUFFICIENT AND REQUIRED FOR TUMORIGENESIS. RECENTLY, AID'S ABILITY TO CLEAVE DNA HAS BEEN SHOWN TO DEPEND ON TOPOISOMERASE 1 (TOP1) AND A HISTONE H3K4 EPIGENETIC MARK. WHEN THE LEVEL OF TOP1 PROTEIN IS DECREASED BY AID ACTIVATION, IT INDUCES IRREVERSIBLE CLEAVAGE IN HIGHLY TRANSCRIBED TARGETS. THIS FINDING AND OTHERS LED TO THE IDEA THAT THERE IS AN EVOLUTIONARY LINK BETWEEN MEIOTIC RECOMBINATION AND CLASS SWITCH RECOMBINATION, WHICH SHARE H3K4 TRIMETHYL, TOPOISOMERASE, THE MRN COMPLEX, MISMATCH REPAIR FAMILY PROTEINS, AND EXONUCLEASE 3. AS TOP1 HAS RECENTLY BEEN SHOWN TO BE INVOLVED IN MANY TRANSCRIPTION-ASSOCIATED GENOME INSTABILITIES, IT IS LIKELY THAT AID TOOK ADVANTAGE OF BASIC GENOME INSTABILITY OR DIVERSIFICATION TO EVOLVE ITS MECHANISM FOR IMMUNE DIVERSITY. AID TARGETS ARE THEREFORE NOT HIGHLY SPECIFIC TO IMMUNOGLOBULIN GENES AND ARE RELATIVELY ABUNDANT, ALTHOUGH THEY HAVE STRICT REQUIREMENTS FOR TRANSCRIPTION-INDUCED H3K4 TRIMETHYL MODIFICATION AND REPETITIVE SEQUENCES PRONE TO FORMING NON-B STRUCTURES. INEVITABLY, AID-DEPENDENT CLEAVAGE TAKES PLACE IN NONIMMUNOGLOBULIN TARGETS AND EVENTUALLY CAUSES TUMORS. HOWEVER, BATTLES AGAINST INFECTION ARE WAGED IN THE CONTEXT OF ACUTE EMERGENCIES, WHILE TUMORIGENESIS IS RATHER A CHRONIC, LONG-TERM PROCESS. IN THE INTEREST OF SURVIVAL, VERTEBRATES MUST HAVE EVOLVED AID TO PREVENT INFECTION DESPITE ITS LONG-TERM RISK OF CAUSING TUMORIGENESIS. 2012 7 6215 20 THE INVOLVEMENT OF ADAR1 IN ANTIDEPRESSANT ACTION BY REGULATING BDNF VIA MIR-432. BRAIN-DERIVED NEUROTROPHIC FACTOR (BDNF) IS A BIOMARKER OF DEPRESSION. RECENT STUDIES HAVE FOUND ADENOSINE DEAMINASE ACTING ON RNA1 (ADAR1) IS A NOVEL TARGET BEING SENSITIVE TO STRESS AT EPIGENETIC LEVEL. THE EPIGENETIC REGULATION MECHANISM OF STRESS-RELATED DEPRESSION IS STILL UNCLEAR SO FAR. TO EXPLORE THE POTENTIAL REGULATING MECHANISM OF ADAR1 ON BDNF, OVER AND LOW EXPRESSION OF ADAR1 IN PC12 AND SH-SY5Y CELL LINES ARE PREPARED. IN THE MEANWHILE, CHRONIC UNPREDICTABLE STRESS (CUS) MICE ARE TREATED WITH ADAR1 INDUCER (INTERFERON-GAMMA, IFN-GAMMA). ADAR1 REGULATES BDNF EXPRESSION, WHICH IS PROVEN BY THAT OVER AND LOW EXPRESSIONS OF ADAR1 INCREASE AND DECREASE BDNF MRNA AND PROTEIN RESPECTIVELY IN VITRO. ADDITIONALLY, ADAR1 INDUCER ALLEVIATES THE DEPRESSIVE-LIKE BEHAVIOR OF CUS MICE BY RECOVERING THE DECREASED BDNF PROTEIN IN BRAIN AND SERUM. MOREOVER, OVER AND LOW EXPRESSIONS OF ADAR1 REDUCE AND ENHANCE MICRORNA-432 (MIR-432) EXPRESSION RESPECTIVELY IN VITRO. FURTHERLY, OVER AND LOW MIR-432 EXPRESSIONS LEAD TO DECREASED AND INCREASED BDNF AND ADAR1 MRNA, PROTEIN AND IMMUNOREACTIVITY RESPECTIVELY IN VITRO. THE ABOVE RESULTS DEMONSTRATE THAT ADAR1 IS INVOLVED IN ANTIDEPRESSANT ACTION BY REGULATING BDNF VIA MIR-432. THOSE NOVEL FINDINGS CAN PROVIDE A NEW IDEA FOR THE STUDY OF EPIGENETIC REGULATION MECHANISM, EARLY DIAGNOSIS, AND EFFECTIVE TREATMENT OF STRESS-RELATED DEPRESSION. 2021 8 208 43 ACTIVATION-INDUCED CYTIDINE DEAMINASE (AID) LINKING IMMUNITY, CHRONIC INFLAMMATION, AND CANCER. ACTIVATION-INDUCED CYTIDINE DEAMINASE (AID) IS CRITICALLY INVOLVED IN CLASS SWITCH RECOMBINATION AND SOMATIC HYPERMUTATION OF IG LOCI RESULTING IN DIVERSIFICATION OF ANTIBODIES REPERTOIRE AND PRODUCTION OF HIGH-AFFINITY ANTIBODIES AND AS SUCH REPRESENTS A PHYSIOLOGICAL TOOL TO INTRODUCE DNA ALTERATIONS. THESE PROCESSES TAKE PLACE WITHIN GERMINAL CENTERS OF SECONDARY LYMPHOID ORGANS. UNDER PHYSIOLOGICAL CONDITIONS, AID IS EXPRESSED PREDOMINANTLY IN ACTIVATED B LYMPHOCYTES. BECAUSE OF THE MUTAGENIC AND RECOMBINOGENIC POTENTIAL OF AID, ITS EXPRESSION AND ACTIVITY IS TIGHTLY REGULATED ON DIFFERENT LEVELS TO MINIMIZE THE RISK OF UNWANTED DNA DAMAGE. HOWEVER, CHRONIC INFLAMMATION AND, PROBABLY, COMBINATION OF OTHER NOT-YET-IDENTIFIED FACTORS ARE ABLE TO CREATE A MICROENVIRONMENT SUFFICIENT FOR TRIGGERING AN ABERRANT AID EXPRESSION IN B CELLS AND, IMPORTANTLY, IN NON-B-CELL BACKGROUND. UNDER THESE CIRCUMSTANCES, AID MAY TARGET ALSO NON-IG GENES, INCLUDING CANCER-RELATED GENES AS ONCOGENES, TUMOR SUPPRESSOR GENES, AND GENOMIC STABILITY GENES, AND MODULATE BOTH GENETIC AND EPIGENETIC INFORMATION. DESPITE ONGOING PROGRESS, THE COMPLETE UNDERSTANDING OF FUNDAMENTAL ASPECTS IS STILL LACKING AS (1) WHAT ARE THE CRUCIAL FACTORS TRIGGERING AN ABERRANT AID EXPRESSION/ACTIVITY INCLUDING THE IMPACT OF TH2-DRIVEN INFLAMMATION AND (2) TO WHAT EXTENT MAY ABERRANT AID IN HUMAN NON-B CELLS LEAD TO ABNORMAL CELL STATE ASSOCIATED WITH AN INCREASED RATE OF GENOMIC ALTERATIONS AS POINT MUTATIONS, SMALL INSERTIONS OR DELETIONS, AND/OR RECURRENT CHROMOSOMAL TRANSLOCATIONS DURING SOLID TUMOR DEVELOPMENT AND PROGRESSION. 2012 9 2837 23 FORKHEAD O TRANSCRIPTION FACTOR 4 RESTRICTS HBV COVALENTLY CLOSED CIRCULAR DNA TRANSCRIPTION AND HBV REPLICATION THROUGH GENETIC DOWNREGULATION OF HEPATOCYTE NUCLEAR FACTOR 4 ALPHA AND EPIGENETIC SUPPRESSION OF COVALENTLY CLOSED CIRCULAR DNA VIA INTERACTING WITH PROMYELOCYTIC LEUKEMIA PROTEIN. NUCLEAR LOCATED HEPATITIS B VIRUS (HBV) COVALENTLY CLOSED CIRCULAR DNA (CCCDNA) REMAINS THE KEY OBSTACLE TO CURE CHRONIC HEPATITIS B (CHB). IN OUR PREVIOUS INVESTIGATION, IT WAS FOUND THAT FOXO4 COULD INHIBIT HBV CORE PROMOTER ACTIVITY THROUGH DOWNREGULATING THE EXPRESSION OF HNF4ALPHA. HOWEVER, THE EXACT MECHANISMS WHEREBY FOXO4 INHIBITS HBV REPLICATION, ESPECIALLY ITS EFFECT ON CCCDNA, REMAIN UNCLEAR. HERE, OUR DATA FURTHER REVEALED THAT FOXO4 COULD EFFECTIVELY INHIBIT CCCDNA MEDIATED TRANSCRIPTION AND HBV REPLICATION WITHOUT AFFECTING CCCDNA LEVEL. MECHANISTIC STUDY SHOWED THAT FOXO4 COULD CAUSE EPIGENETIC SUPPRESSION OF CCCDNA. ALTHOUGH FOXO4-MEDIATED DOWNREGULATION OF HNF4ALPHA CONTRIBUTED TO INHIBITING HBV CORE PROMOTER ACTIVITY, IT HAD LITTLE EFFECT ON CCCDNA EPIGENETIC REGULATION. FURTHER, IT WAS FOUND THAT FOXO4 COULD COLOCALIZE WITHIN PROMYELOCYTIC LEUKEMIA PROTEIN (PML) NUCLEAR BODIES AND INTERACT WITH PML. OF NOTE, PML WAS REVEALED TO BE CRITICAL FOR FOXO4-MEDIATED INHIBITION OF CCCDNA EPIGENETIC MODIFICATION AND OF THE FOLLOWING CCCDNA TRANSCRIPTION AND HBV REPLICATION. FURTHERMORE, FOXO4 WAS FOUND TO BE DOWNREGULATED IN HBV-INFECTED HEPATOCYTES AND HUMAN LIVER TISSUES, AND IT WAS NEGATIVELY CORRELATED WITH CCCDNA TRANSCRIPTIONAL ACTIVITY IN CHB PATIENTS. TOGETHER, THESE FINDINGS HIGHLIGHT THE ROLE OF FOXO4 IN SUPPRESSING CCCDNA TRANSCRIPTION AND HBV REPLICATION VIA GENETIC DOWNREGULATION OF HNF4ALPHA AND EPIGENETIC SUPPRESSION OF CCCDNA THROUGH INTERACTING WITH PML. TARGETING FOXO4 MAY PRESENT AS A NEW THERAPEUTIC STRATEGY AGAINST CHRONIC HBV INFECTION. IMPORTANCE HBV CCCDNA IS A DETERMINING FACTOR FOR VIRAL PERSISTENCE AND THE MAIN OBSTACLE FOR A CURE OF CHRONIC HEPATITIS B. STRATEGIES THAT TARGET CCCDNA DIRECTLY ARE THEREFORE OF GREAT IMPORTANCE IN CONTROLLING PERSISTENT HBV INFECTION. IN PRESENT INVESTIGATION, WE FOUND THAT FOXO4 COULD EFFICIENTLY SUPPRESS CCCDNA TRANSCRIPTION AND HBV REPLICATION WITHOUT AFFECTING THE LEVEL OF CCCDNA ITSELF. FURTHER, OUR DATA REVEALED THAT FOXO4 MIGHT INHIBIT CCCDNA FUNCTION VIA A TWO-PART MECHANISM: ONE IS TO EPIGENETICALLY SUPPRESS CCCDNA TRANSCRIPTION VIA INTERACTING WITH PML, AND THE OTHER IS TO INHIBIT HBV CORE PROMOTER ACTIVITY VIA THE GENETIC DOWNREGULATION OF HNF4ALPHA. OF NOTE, HBV MIGHT DAMPEN THE EXPRESSION OF FOXO4 FOR ITS OWN PERSISTENT INFECTION. WE PROPOSE THAT MANIPULATION OF FOXO4 MAY PRESENT AS A POTENTIAL THERAPEUTIC STRATEGY AGAINST CHRONIC HBV INFECTION. 2022 10 209 30 ACTIVATION-INDUCED CYTIDINE DEAMINASE: IN SICKNESS AND IN HEALTH. ACTIVATION INDUCED CYTIDINE DEAMINASE (AID) IS AN ESSENTIAL ENZYME OF THE ADAPTIVE IMMUNE SYSTEM. ITS CANONICAL ACTIVITY IS RESTRICTED TO B LYMPHOCYTES, PLAYING AN ESSENTIAL ROLE IN THE DIVERSIFICATION OF ANTIBODIES BY ENHANCING SPECIFICITY AND CHANGING AFFINITY. THIS IS POSSIBLE THROUGH ITS DNA DEAMINASE FUNCTION, LEADING TO MUTATIONS IN DNA. IN THE LAST DECADE, AID HAS BEEN ASSIGNED AN ADDITIONAL FUNCTION: THAT OF A POWERFUL DNA DEMETHYLATOR. ADVERSE CELLULAR CONDITIONS SUCH AS CHRONIC INFLAMMATION CAN LEAD TO ITS DEREGULATION AND OVEREXPRESSION. IT IS AN IMPORTANT DRIVER OF B-CELL LYMPHOMA DUE TO ITS NATURAL ABILITY TO MODIFY DNA THROUGH DEAMINATION, LEADING TO MUTATIONS AND EPIGENETIC CHANGES. HOWEVER, THE DEREGULATION OF AID IS NOT RESTRICTED TO LYMPHOID CELLS. RECENT FINDINGS HAVE PROVIDED NEW INSIGHTS INTO THE ROLE THAT THIS PROTEIN PLAYS IN THE DEVELOPMENT OF NON-LYMPHOID CANCERS, WITH SOME RESEARCH SHEDDING LIGHT ON NOVEL AID-DRIVEN MECHANISMS OF CELLULAR TRANSFORMATION. IN THIS REVIEW, WE PROVIDE AN UPDATED NARRATIVE OF THE NORMAL PHYSIOLOGICAL FUNCTIONS OF AID. ADDITIONALLY, WE REVIEW AND DISCUSS THE RECENT RESEARCH STUDIES THAT HAVE IMPLICATED AID IN CARCINOGENESIS IN VARYING TISSUE TYPES INCLUDING LYMPHOID AND NON-LYMPHOID CANCERS. WE REVIEW THE MECHANISMS, WHEREBY AID PROMOTES CARCINOGENESIS AND HIGHLIGHT IMPORTANT AREAS OF FUTURE RESEARCH. 2020 11 2428 23 EPIGENETIC SILENCING OF MIR-124 PREVENTS SPERMINE OXIDASE REGULATION: IMPLICATIONS FOR HELICOBACTER PYLORI-INDUCED GASTRIC CANCER. CHRONIC INFLAMMATION CONTRIBUTES TO THE DEVELOPMENT OF VARIOUS FORMS OF CANCER. THE POLYAMINE CATABOLIC ENZYME SPERMINE OXIDASE (SMOX) IS INDUCED IN CHRONIC INFLAMMATORY CONDITIONS, INCLUDING HELICOBACTER PYLORI-ASSOCIATED GASTRITIS, WHERE ITS PRODUCTION OF HYDROGEN PEROXIDE CONTRIBUTES TO DNA DAMAGE AND SUBSEQUENT TUMORIGENESIS. MICRORNA EXPRESSION LEVELS ARE ALSO ALTERED IN INFLAMMATORY CONDITIONS; SPECIFICALLY, THE TUMOR SUPPRESSOR MIR-124 BECOMES SILENCED BY DNA METHYLATION. WE SOUGHT TO DETERMINE IF THIS REPRESSION OF MIR-124 IS ASSOCIATED WITH ELEVATED SMOX ACTIVITY AND CONCLUDED THAT MIR-124 IS INDEED A NEGATIVE REGULATOR OF SMOX. IN GASTRIC ADENOCARCINOMA CELLS HARBORING HIGHLY METHYLATED AND SILENCED MIR-124 GENE LOCI, 5-AZACYTIDINE TREATMENT ALLOWED MIR-124 RE-EXPRESSION AND DECREASED SMOX EXPRESSION. OVEREXPRESSION OF AN EXOGENOUS MIR-124-3P MIMIC REPRESSED SMOX MRNA AND PROTEIN EXPRESSION AS WELL AS H(2)O(2) PRODUCTION BY >50% WITHIN 24 H. REPORTER ASSAYS INDICATED THAT DIRECT INTERACTION OF MIR-124 WITH THE 3'-UNTRANSLATED REGION OF SMOX MRNA CONTRIBUTES TO THIS NEGATIVE REGULATION. IMPORTANTLY, OVEREXPRESSION OF MIR-124 BEFORE INFECTION WITH H. PYLORI PREVENTED THE INDUCTION OF SMOX BELIEVED TO CONTRIBUTE TO INFLAMMATION-ASSOCIATED TUMORIGENESIS. COMPELLING HUMAN IN VIVO DATA FROM H. PYLORI-POSITIVE GASTRITIS TISSUES INDICATED THAT THE MIR-124 GENE LOCI ARE MORE HEAVILY METHYLATED IN A COLOMBIAN POPULATION CHARACTERIZED BY ELEVATED SMOX EXPRESSION AND A HIGH RISK FOR GASTRIC CANCER. FURTHERMORE, THE DEGREE OF MIR-124 METHYLATION SIGNIFICANTLY CORRELATED WITH SMOX EXPRESSION THROUGHOUT THE POPULATION. THESE RESULTS INDICATE A PROTECTIVE ROLE FOR MIR-124 THROUGH THE INHIBITION OF SMOX-MEDIATED DNA DAMAGE IN THE ETIOLOGY OF H. PYLORI-ASSOCIATED GASTRIC CANCER. 2016 12 4754 18 NOVEL THERAPEUTIC STRATEGIES FOR CHRONIC HEPATITIS B. THE LAST FEW YEARS HAVE SEEN A RESURGENCE OF ACTIVITY IN THE HEPATITIS B DRUG PIPELINE, WITH MANY COMPOUNDS IN VARIOUS STAGES OF DEVELOPMENT. THIS REVIEW AIMS TO PROVIDE A COMPREHENSIVE OVERVIEW OF THE LATEST ADVANCES IN THERAPEUTICS FOR CHRONIC HEPATITIS B (CHB). WE WILL DISCUSS THE BROAD SPECTRUM OF DIRECT-ACTING ANTIVIRALS IN CLINICAL DEVELOPMENT, INCLUDING CAPSIDS INHIBITORS, SIRNA, HBSAG AND POLYMERASE INHIBITORS. IN ADDITION, HOST-TARGETED THERAPIES (HTT) WILL BE EXTENSIVELY REVIEWED, FOCUSING ON THE LATEST PROGRESS IN IMMUNOTHERAPEUTICS SUCH AS TOLL-LIKE RECEPTORS AND RIG-1 AGONISTS, THERAPEUTIC VACCINES AND IMMUNE CHECKPOINTS MODULATORS. A GROWING NUMBER OF HTT IN PRE-CLINICAL DEVELOPMENT DIRECTLY TARGET THE KEY TO HBV PERSISTENCE, NAMELY THE COVALENTLY CLOSED CIRCULAR DNA (CCCDNA) AND HOLD GREAT PROMISE FOR HBV CURE. THIS EXCITING AREA OF HBV RESEARCH WILL BE HIGHLIGHTED, AND MOLECULES SUCH AS CYCLOPHILINS INHIBITORS, APOBEC3 DEAMINASES AND EPIGENETIC MODIFIERS WILL BE DISCUSSED. 2022 13 4771 21 NUCLEAR SENSOR INTERFERON-INDUCIBLE PROTEIN 16 INHIBITS THE FUNCTION OF HEPATITIS B VIRUS COVALENTLY CLOSED CIRCULAR DNA BY INTEGRATING INNATE IMMUNE ACTIVATION AND EPIGENETIC SUPPRESSION. BACKGROUND AND AIMS: NUCLEAR-LOCATED COVALENTLY CLOSED CIRCULAR DNA (CCCDNA) OF HEPATITIS B VIRUS (HBV) IS A DETERMINING FACTOR FOR HBV PERSISTENCE AND THE KEY OBSTACLE FOR A CURE OF CHRONIC HEPATITIS B. HOWEVER, IT REMAINS UNCLEAR WHETHER AND HOW THE HOST IMMUNE SYSTEM SENSES HBV CCCDNA AND ITS BIOLOGICAL CONSEQUENCES. APPROACH AND RESULTS: HERE, WE DEMONSTRATED THAT INTERFERON-INDUCIBLE PROTEIN 16 (IFI16) COULD SERVE AS A UNIQUE INNATE SENSOR TO RECOGNIZE AND BIND TO HBV CCCDNA IN HEPATIC NUCLEI, LEADING TO THE INHIBITION OF CCCDNA TRANSCRIPTION AND HBV REPLICATION. MECHANISTICALLY, OUR DATA SHOWED THAT IFI16 PROMOTED THE EPIGENETIC SUPPRESSION OF HBV CCCDNA BY TARGETING AN INTERFERON-STIMULATED RESPONSE ELEMENT (ISRE) PRESENT IN CCCDNA. IT IS OF INTEREST THAT THIS ISRE WAS ALSO REVEALED TO PLAY AN IMPORTANT ROLE IN IFI16-ACTIVATED TYPE I INTERFERON RESPONSES. FURTHERMORE, OUR DATA REVEALED THAT HBV COULD DOWN-REGULATE THE EXPRESSION LEVEL OF IFI16 IN HEPATOCYTES, AND THERE WAS A NEGATIVE CORRELATION BETWEEN IFI16 AND HBV TRANSCRIPTS IN LIVER BIOPSIES, SUGGESTING THE POSSIBLE ROLE OF IFI16 IN SUPPRESSING CCCDNA FUNCTION UNDER PHYSIOLOGICAL CONDITIONS. CONCLUSIONS: THE NUCLEAR SENSOR IFI16 SUPPRESSES CCCDNA FUNCTION BY INTEGRATING INNATE IMMUNE ACTIVATION AND EPIGENETIC REGULATION BY TARGETING THE ISRE OF CCCDNA, AND IFI16 MAY PRESENT AS A THERAPEUTIC TARGET AGAINST HBV INFECTION. 2020 14 5678 20 SHORT HAIRPIN RNA INDUCES METHYLATION OF HEPATITIS B VIRUS COVALENTLY CLOSED CIRCULAR DNA IN HUMAN HEPATOMA CELLS. SMALL INTERFERING RNAS NOT ONLY MODULATE GENE EXPRESSION AT A POST-TRANSCRIPTIONAL LEVEL, BUT ALSO INDUCE TRANSCRIPTIONAL GENE SILENCING BY RNA INTERFERENCE-MEDIATED HETEROCHROMATIN FORMATION AND RNA-DIRECTED DNA METHYLATION (RDDM). HOWEVER, ALTHOUGH ESTABLISHED IN PLANTS, THERE HAVE BEEN CONTROVERSIES WHETHER RDDM OPERATES IN MAMMALS. HEPATITIS B VIRUS (HBV) COVALENTLY CLOSED CIRCULAR DNA (CCCDNA) SERVES AS A TEMPLATE FOR VIRAL RNA TRANSCRIPTION, AND TRANSCRIPTIONAL ACTIVITY OF HBV CCCDNA IS REGULATED BY METHYLATION IN PATIENTS WITH CHRONIC HBV INFECTION. IN THIS STUDY, WE STABLY EXPRESSED SHORT HAIRPIN RNA (SHRNA) AGAINST HBV IN HUMAN HEPATOMA CELLS TO DETERMINE WHETHER SHRNA INDUCES METHYLATION OF HBV CCCDNA. HEPAD38 CELLS WHICH PERMIT REPLICATION OF HBV UNDER CONTROL OF TETRACYCLINE-RESPONSIVE PROMOTER WERE TRANSDUCED WITH LENTIVIRAL VECTORS WHICH ENCODE SH-1580, A SHRNA AGAINST THE HEPATITIS B VIRAL PROTEIN HBX. BISULFITE SEQUENCING PCR ANALYSIS REVEALED THAT SH-1580 INDUCED CPG METHYLATIONS AT A HIGHER RATE COMPARED TO CONTROL (31.3% VS. 12.8%, P<0.05). THE SH-1580-INDUCED CPG METHYLATION WAS LOCALIZED NEAR THE TARGET SEQUENCE OF SH-1580 IN MORE THAN A HALF OF THE CLONES. METHYLATION-INDUCED TRANSCRIPTIONAL SUPPRESSION WAS CONFIRMED BY IN VITRO TRANSCRIPTION ASSAY. THESE RESULTS CONFIRM THE FEASIBILITY OF RDDM OF HBV CCCDNA IN HUMAN CELLS. LENTIVIRAL VECTOR-MEDIATED TRANSFER OF SHRNA MAY BE USED AS A TOOL FOR NOVEL TRANSCRIPTIONAL MODULATION BY EPIGENETIC MODIFICATION OF HBV CCCDNA. 2013 15 130 21 A-TO-I EDITING OF MIR-200B-3P IN AIRWAY CELLS IS ASSOCIATED WITH MODERATE-TO-SEVERE ASTHMA. BACKGROUND: ASTHMA IS A CHRONIC LUNG DISEASE CHARACTERISED BY PERSISTENT AIRWAY INFLAMMATION. ALTERED MICRORNA (MIRNA)-MEDIATED GENE SILENCING IN BRONCHIAL EPITHELIAL CELLS (BECS) HAS BEEN REPORTED IN ASTHMA, YET ADENOSINE DEAMINASE ACTING ON RNA (ADAR)-MEDIATED MIRNA EDITING IN ASTHMA REMAINS UNEXPLORED. METHODS: WE FIRST IDENTIFIED ADENOSINE TO INOSINE (A-TO-I) EDITED SITES IN MIRNAS IN BECS FROM 142 ADULT ASTHMA CASES AND CONTROLS. A-TO-I EDITED SITES WERE TESTED FOR ASSOCIATIONS WITH ASTHMA SEVERITY AND CLINICAL MEASURES OF ASTHMA. PAIRED RNA SEQUENCING DATA WERE USED TO PERFORM PATHWAY ENRICHMENTS AND TEST FOR ASSOCIATIONS WITH BIOINFORMATICALLY PREDICTED TARGET GENES OF THE UNEDITED AND EDITED MIRNAS. RESULTS: OF 19 A-TO-I EDITED SITES DETECTED IN THESE MIRNAS, ONE SITE AT POSITION 5 OF MIR-200B-3P WAS EDITED LESS FREQUENTLY IN CASES COMPARED WITH CONTROLS (P(CORRECTED)=0.013), AND ESPECIALLY COMPARED WITH CASES WITH MODERATE (P(CORRECTED)=0.029) AND SEVERE (P(CORRECTED)=3.9X10(-4)), BUT NOT MILD (P(CORRECTED)=0.38), ASTHMA. BIOINFORMATIC PREDICTION REVEALED 232 TARGET GENES OF THE EDITED MIR-200B-3P, WHICH WERE ENRICHED FOR BOTH INTERLEUKIN-4 AND INTERFERON-GAMMA SIGNALLING PATHWAYS, AND INCLUDED THE SOCS1 (SUPPRESSOR OF CYTOKINE SIGNALLING 1) GENE. SOCS1 WAS MORE HIGHLY EXPRESSED IN MODERATE (P(CORRECTED)=0.017) AND SEVERE (P(CORRECTED)=5.4X10(-3)) ASTHMA CASES COMPARED WITH CONTROLS. MOREOVER, BOTH MIR-200B-3P EDITING AND SOCS1 WERE ASSOCIATED WITH BRONCHOALVEOLAR LAVAGE EOSINOPHIL LEVELS. CONCLUSIONS: REDUCED A-TO-I EDITING OF POSITION 5 OF MIR-200B-3P IN LOWER AIRWAY CELLS FROM MODERATE-TO-SEVERE ASTHMATIC SUBJECTS MAY LEAD TO OVEREXPRESSION OF SOCS1 AND IMPAIRED CYTOKINE SIGNALLING. WE PROPOSE ADAR-MEDIATED EDITING AS AN EPIGENETIC MECHANISM CONTRIBUTING TO FEATURES OF MODERATE-TO-SEVERE ASTHMA IN ADULTHOOD. 2021 16 671 21 BOTHROPS MOOJENI L-AMINO ACID OXIDASE INDUCES APOPTOSIS AND EPIGENETIC MODULATION ON BCR-ABL(+) CELLS. BACKGROUND: RESISTANCE TO APOPTOSIS IN CHRONIC MYELOID LEUKEMIA (CML) IS ASSOCIATED WITH CONSTITUTIVE TYROSINE KINASE ACTIVITY OF THE BCR-ABL ONCOPROTEIN. THE DEREGULATED EXPRESSION OF APOPTOSIS-RELATED GENES AND ALTERATION IN EPIGENETIC MACHINERY MAY ALSO CONTRIBUTE TO APOPTOSIS RESISTANCE IN CML. TYROSINE KINASE INHIBITORS TARGET THE BCR-ABL ONCOPROTEIN AND ARE USED IN CML TREATMENT. THE RESISTANCE OF CML PATIENTS TO TYROSINE KINASE INHIBITORS HAS GUIDED THE SEARCH FOR NEW COMPOUNDS THAT MAY INDUCE APOPTOSIS IN BCR-ABL(+) LEUKEMIC CELLS AND IMPROVE THE DISEASE TREATMENT. METHODS: IN THE PRESENT STUDY, WE INVESTIGATED WHETHER THE L-AMINO ACID OXIDASE ISOLATED FROM BOTHROPS MOOJENI SNAKE VENOM (BMOOLAAO-I) (I) WAS CYTOTOXIC TO BCR-ABL(+) CELL LINES (HL-60.BCR-ABL, K562-S, AND K562-R), HL-60 (ACUTE PROMYELOCYTIC LEUKEMIA) CELLS, THE NON-TUMOR CELL LINE HEK-293, AND PERIPHERAL BLOOD MONONUCLEAR CELLS (PBMC); AND (II) AFFECTED EPIGENETIC MECHANISMS, INCLUDING DNA METHYLATION AND MICRORNAS EXPRESSION IN VITRO. RESULTS: BMOOLAAO-I INDUCED ROS PRODUCTION, APOPTOSIS, AND DIFFERENTIAL DNA METHYLATION PATTERN OF REGULATORY APOPTOSIS GENES. THE TOXIN UPREGULATED EXPRESSION OF THE PRO-APOPTOTIC GENES BID AND FADD AND DOWNREGULATED DFFA EXPRESSION IN LEUKEMIC CELL LINES, AS WELL AS INCREASED MIR-16 EXPRESSION - WHOSE MAJOR PREDICTED TARGET IS THE ANTI-APOPTOTIC GENE BCL2 - IN BCR-ABL(+) CELLS. CONCLUSION: BMOOLAAO-I EXERTS SELECTIVE ANTITUMOR ACTION MEDIATED BY H(2)O(2) RELEASE AND INDUCES APOPTOSIS, AND ALTERATIONS IN EPIGENETIC MECHANISMS. THESE RESULTS SUPPORT FUTURE INVESTIGATIONS ON THE EFFECT OF BMOOLAAO-I ON IN VIVO MODELS TO DETERMINE ITS POTENTIAL IN CML THERAPY. 2020 17 6448 18 THERAPEUTIC SHUTDOWN OF HBV TRANSCRIPTS PROMOTES REAPPEARANCE OF THE SMC5/6 COMPLEX AND SILENCING OF THE VIRAL GENOME IN VIVO. OBJECTIVE: THERAPEUTIC STRATEGIES SILENCING AND REDUCING THE HEPATITIS B VIRUS (HBV) RESERVOIR, THE COVALENTLY CLOSED CIRCULAR DNA (CCCDNA), HAVE THE POTENTIAL TO CURE CHRONIC HBV INFECTION. WE AIMED TO INVESTIGATE THE IMPACT OF SMALL INTERFERRING RNA (SIRNA) TARGETING ALL HBV TRANSCRIPTS OR PEGYLATED INTERFERON-ALPHA (PEG-IFNALPHA) ON THE VIRAL REGULATORY HBX PROTEIN AND THE STRUCTURAL MAINTENANCE OF CHROMOSOME 5/6 COMPLEX (SMC5/6), A HOST FACTOR SUPPRESSING CCCDNA TRANSCRIPTION. IN PARTICULAR, WE ASSESSED WHETHER INTERVENTIONS LOWERING HBV TRANSCRIPTS CAN ACHIEVE AND MAINTAIN SILENCING OF CCCDNA TRANSCRIPTION IN VIVO. DESIGN: HBV-INFECTED HUMAN LIVER CHIMERIC MICE WERE TREATED WITH SIRNA OR PEG-IFNALPHA. VIROLOGICAL AND HOST CHANGES WERE ANALYSED AT THE END OF TREATMENT AND DURING THE REBOUND PHASE BY QUALITATIVE PCR, ELISA, IMMUNOBLOTTING AND CHROMATIN IMMUNOPRECIPITATION. RNA IN SITU HYBRIDISATION WAS COMBINED WITH IMMUNOFLUORESCENCE TO DETECT SMC6 AND HBV RNAS AT SINGLE CELL LEVEL. THE ENTRY INHIBITOR MYRCLUDEX-B WAS USED DURING THE REBOUND PHASE TO AVOID NEW INFECTION EVENTS. RESULTS: BOTH SIRNA AND PEG-IFNALPHA STRONGLY REDUCED ALL HBV MARKERS, INCLUDING HBX LEVELS, THUS ENABLING THE REAPPEARANCE OF SMC5/6 IN HEPATOCYTES THAT ACHIEVED HBV-RNA NEGATIVISATION AND SMC5/6 ASSOCIATION WITH THE CCCDNA. ONLY IFN REDUCED CCCDNA LOADS AND ENHANCED IFN-STIMULATED GENES. HOWEVER, THE ANTIVIRAL EFFECTS DID NOT PERSIST OFF TREATMENT AND SMC5/6 WAS AGAIN DEGRADED. REMARKABLY, THE BLOCKADE OF VIRAL ENTRY THAT STARTED AT THE END OF TREATMENT HINDERED RENEWED DEGRADATION OF SMC5/6. CONCLUSION: THESE RESULTS REVEAL THAT THERAPEUTICS ABROGATING ALL HBV TRANSCRIPTS INCLUDING HBX PROMOTE EPIGENETIC SUPPRESSION OF THE HBV MINICHROMOSOME, WHEREAS STRATEGIES PROTECTING THE HUMAN HEPATOCYTES FROM REINFECTION ARE NEEDED TO MAINTAIN CCCDNA SILENCING. 2022 18 1657 23 DOWN-EXPRESSION OF MIR-152 LEAD TO IMPAIRED ANTI-TUMOR EFFECT OF NK VIA UPREGULATION OF HLA-G. IT IS KNOWN THAT CHRONIC HBV INFECTION (CHB) IS THE MAJOR RISK FACTOR FOR HEPATOCELLULAR CARCINOMA (HCC) BECAUSE CHB COULD NOT ONLY CAUSE LIVER TUMORIGENESIS BUT ALSO LEAD TO CHANGE OF LOCAL MICROENVIROMENT AND LOWER IMMUNE RESPONSE TO INFECTED AND CANCEROUS CELLS (IMMUNE TOLERANCE). HUMAN LEUCOCYTE ANTIGEN-G (HLA-G) BELONGS TO A NON-CLASSIC MHC-I FAMILY AND WAS CONSIDERED TO BE AN IMMUNE TOLERANCE MOLECULE, WHICH COULD BIND TO IMMUNOSUPPRESSIVE RECEPTORS OF NATURAL KILLER CELL (NK) AND T CELLS AND TRIGGER IMMUNOSUPPRESSIVE SIGNALING. RECENTLY, NUMEROUS STUDIES HIGHLIGHTED THAT MICRORNAS (MIRNAS) WERE SIGNIFICANTLY DIFFERENTIALLY EXPRESSED IN HCC TUMORIGENESIS, AND THE EXPRESSION WAS TISSUE-SPECIFIC, INDICATING THAT MIRNAS MAY CAUSE GREAT EPIGENETIC CHANGES IN HCC TUMORIGENESIS. IN THIS STUDY, WE FOUND THAT THE EXPRESSION OF HLA-G WAS UPREGULATED BY HEPATITIS B VIRUS (HBV) INFECTION AND MIR-152; A HLA-G-TARGETING MIRNA WAS DOWNREGULATED BY HBV INFECTION. AND HIGH EXPRESSION OF HLA-G FURTHER SUPPRESSED NK AGAINST CANCER CELLS, PROVIDING A NEW CONCEPT THAT MIR-152 WAS INVOLVED IN HBV-INDUCED HEPATOCELLULAR CARCINOMA. 2016 19 3249 16 HEPATITIS B VIRUS HIJACKS CTHRC1 TO EVADE HOST IMMUNITY AND MAINTAIN REPLICATION. HEPATITIS B VIRUS (HBV) INFECTION CAUSES ACUTE AND CHRONIC LIVER DISEASES, BUT IS NOT DIRECTLY CYTOPATHIC. LIVER INJURY RESULTS FROM REPEATED ATTEMPTS OF THE CELLULAR IMMUNE RESPONSE SYSTEM TO CONTROL THE VIRAL INFECTION. HERE, WE INVESTIGATE THE ROLES OF CELLULAR FACTORS AND SIGNALING PATHWAYS INVOLVED IN THE REGULATION OF HBV REPLICATION TO REVEAL THE MECHANISM UNDERLYING HBV INFECTION AND PATHOGENESIS. WE SHOW THAT COLLAGEN TRIPLE HELIX REPEAT CONTAINING 1 (CTHRC1) EXPRESSION IS ELEVATED IN HBV-INFECTED PATIENTS AND IN HBV-TRANSFECTED CELLS THROUGH EPIGENETIC MODIFICATION AND TRANSCRIPTIONAL REGULATION. CTHRC1 FACILITATES HBV REPLICATION IN CULTURED CELLS AND BALB/C MICE BY ACTIVATING THE PKCALPHA/ERK/JNK/C-JUN CASCADE TO REPRESS THE IFN/JAK/STAT PATHWAY. HBV-ACTIVATED CTHRC1 DOWNREGULATES THE ACTIVITY OF TYPE I INTERFERON (IFN), THE PRODUCTION OF IFN-STIMULATED GENES (ISGS), AND THE PHOSPHORYLATION OF SIGNAL TRANSDUCER AND ACTIVATOR OF TRANSCRIPTION 1/2 (STAT1/2), WHEREAS IT UPREGULATES THE PHOSPHORYLATION AND UBIQUITINATION OF TYPE I IFN RECEPTORS (IFNARALPHA/BETA). THUS, OUR RESULTS SHOW THAT HBV USES A NOVEL MECHANISM TO HIJACK CELLULAR FACTORS AND SIGNAL CASCADES IN ORDER TO EVADE HOST ANTIVIRAL IMMUNITY AND MAINTAIN PERSISTENT INFECTION. WE ALSO DEMONSTRATE THAT CTHRC1 HAS A NOVEL ROLE IN VIRAL INFECTION. 2015 20 2432 18 EPIGENETIC SILENCING OF MIR-708 ENHANCES NF-KAPPAB SIGNALING IN CHRONIC LYMPHOCYTIC LEUKEMIA. MICRORNAS (MIRNAS) ARE POST-TRANSCRIPTIONAL REGULATORS OF GENE EXPRESSION AND THEIR DEREGULATION IS INVOLVED IN TUMOR DEVELOPMENT. EPIGENETIC GENE SILENCING IN CANCER BY DNA METHYLATION CONTRIBUTES TO THE SILENCING OF TUMOR-SUPPRESSOR GENES, INCLUDING MIRNAS. WE HAVE RECENTLY SHOWN THAT THE PROMOTER OF MIR-708 IS ABERRANTLY METHYLATED IN CHRONIC LYMPHOCYTIC LEUKEMIA (CLL). TO CHARACTERIZE THE MOLECULAR SIGNALING NETWORKS THAT ARE INFLUENCED BY MIR-708, WE PERFORMED A LUCIFERASE-BASED SCREEN EVALUATING THE EFFECTS OF ECTOPIC MIR-708 EXPRESSION ON LEUKEMIA-RELEVANT SIGNALING PATHWAYS. WE FOUND THAT MIR-708 STRONGLY REPRESSED NF-KAPPAB SIGNALING, A PATHWAY KNOWN TO BE DEREGULATED IN CLL. AMONG THE PREDICTED MIR-708 TARGETS WAS IKKBETA (INHIBITOR OF KAPPA LIGHT POLYPEPTIDE GENE ENHANCER IN B CELLS, KINASE-BETA/IKBKB), A KEY KINASE FACILITATING NF-KAPPAB SIGNALING. WE VALIDATED THE INTERACTION OF MIR-708 WITH THE 3'-UNTRANSLATED REGION OF IKKBETA AND FOUND THAT MIR-708 OVEREXPRESSION REPRESSES ENDOGENOUS IKKBETA. PHOSPHORYLATION OF THE IKKBETA TARGET IKAPPABALPHA AND EXPRESSION OF KNOWN NF-KAPPAB TARGET GENES WERE IMPAIRED BY MIR-708. FURTHERMORE, WE IDENTIFIED AN ENHANCER REGION DOWNSTREAM OF THE MIR-708 PROMOTER THAT DISPLAYS A DISTINCT DNA METHYLATION STATUS IN CLL. HIGH ENHANCER METHYLATION IS SIGNIFICANTLY CORRELATED WITH LOWER MIR-708 EXPRESSION AND IS PREDOMINANTLY FOUND IN PATIENTS WITH POOR PROGNOSIS AND SHORTER TIME TO TREATMENT. THESE RESULTS DEMONSTRATE THAT MIR-708 REGULATES THE NF-KAPPAB PATHWAY BY TARGETING IKKBETA, AND THAT METHYLATION OF A KEY ENHANCER REGION CONTRIBUTES TO ITS SUPPRESSION IN CLL. 2015