1 5220 74 PRIMARY BILIARY CHOLANGITIS: A TALE OF EPIGENETICALLY-INDUCED SECRETORY FAILURE? PRIMARY BILIARY CHOLANGITIS (PBC) IS A CHRONIC CHOLESTATIC LIVER DISEASE ASSOCIATED WITH AUTOIMMUNE-RELATED DESTRUCTION OF SMALL TO MEDIUM SIZE INTRAHEPATIC BILE DUCTS. THE AETIOLOGY OF PBC IS UNKNOWN AND ITS PATHOGENESIS REMAINS OBSCURE. BOTH GENETIC VARIANTS AND ENVIRONMENTAL FACTORS HAVE BEEN LINKED TO INCREASED PBC SUSCEPTIBILITY, WITH OTHER ALTERATIONS KNOWN TO COOPERATE IN DISEASE PATHOBIOLOGY. INCREASING EVIDENCE INDICATES THE PRESENCE OF EPIGENETIC ABNORMALITIES IN PBC, PARTICULARLY ALTERATIONS OF CHOLANGIOCELLULAR MICRORNAS (MIRNAS OR MIRS). THIS REVIEW HIGHLIGHTS AND DISCUSSES THE MOST RELEVANT EPIGENETIC ALTERATIONS FOUND IN PATIENTS WITH PBC, FOCUSING ON THE ROLE OF MIR-506 IN THE PROMOTION OF CHOLESTASIS AND IMMUNE ACTIVATION. 2018 2 3012 37 GENETICS AND EPIGENETICS IN THE PATHOGENESIS OF PRIMARY BILIARY CHOLANGITIS. PRIMARY BILIARY CHOLANGITIS (PBC) IS A CHRONIC, SLOWLY PROGRESSIVE CHOLESTATIC AUTOIMMUNE LIVER DISEASE PREDOMINANTLY AFFLICTING WOMEN. PBC IS CHARACTERIZED BY THE PRESENCE OF DISEASE-SPECIFIC ANTIMITOCHONDRIAL ANTIBODIES AND THE HISTOLOGICAL DESTRUCTION OF INTRAHEPATIC BILE DUCTS, WHICH EVENTUALLY LEAD TO CIRRHOSIS AND HEPATIC FAILURE. FORTUNATELY, URSODEOXYCHOLIC ACID THERAPY HAS IMPROVED THE OUTCOME OF THE VAST MAJORITY OF PBC CASES. ALTHOUGH THE ETIOLOGY OF PBC HAS NOT YET BEEN ELUCIDATED, HUMAN LEUKOCYTE ANTIGEN (HLA) CLASS II ALLELES HAVE BEEN CONSISTENTLY ASSOCIATED WITH DISEASE ONSET FOR DECADES. PBC PATIENTS MAY ALSO HAVE GENETICALLY DETERMINED RISK FACTORS IN NON-HLA REGIONS. MEANWHILE, EXPOSURE TO ENVIRONMENTAL FACTORS, SUCH AS INFECTIOUS DISEASES AND HARMFUL CHEMICALS, CAN PRODUCE EPIGENETIC ALTERATIONS IN SOME INDIVIDUALS AND SUBSEQUENT PBC ONSET. IN THIS REVIEW, WE DESCRIBE THE INFLUENCE OF HLA ALLELES AND OTHER GENE POLYMORPHISMS ON PBC ALONG WITH THE RESULTS OF GENOME-WIDE ASSOCIATION STUDIES ON THIS DISEASE AND ITS FUTURE PROSPECTS IN TERMS OF EPIGENETICS. 2018 3 5506 33 RHEUMATOID ARTHRITIS AND PRIMARY BILIARY CIRRHOSIS: CAUSE, CONSEQUENCE, OR COINCIDENCE? PRIMARY BILIARY CIRRHOSIS (PBC) IS A PROGRESSIVE CHOLESTATIC LIVER DISEASE CHARACTERIZED SEROLOGICALLY BY CHOLESTASIS AND THE PRESENCE OF HIGH-TITRE ANTIMITOCHONDRIAL ANTIBODIES AND HISTOLOGICALLY BY CHRONIC NONSUPPURATIVE CHOLANGITIS AND GRANULOMATA. PBC PATIENTS OFTEN HAVE CONCOMITANT AUTOIMMUNE DISEASES, INCLUDING ARTHROPATHIES. THIS RAISES THE QUESTION AS TO WHETHER THERE ARE SHARED FEATURES IN THE PATHOGENESIS OF THOSE DISEASES WITH THE PATHOGENESIS OF PBC. EPIDEMIOLOGICAL AND LARGE CASE STUDIES HAVE INDICATED THAT ALTHOUGH THE INCIDENCE OF RHEUMATOID ARTHRITIS (RA) IS NOT SIGNIFICANTLY RAISED IN PBC PATIENTS, THERE APPEARS TO BE A HIGHER RATE OF RA IN PBC PATIENTS AND THEIR RELATIVES. GENETIC STUDIES HAVE DEMONSTRATED THAT SEVERAL GENES IMPLICATED IN PBC HAVE ALSO BEEN IMPLICATED IN RA. EPIGENETIC STUDIES PROVIDED A WEALTH OF DATA REGARDING RA, BUT THE FINDINGS ON EPIGENETIC CHANGES IN PBC ARE VERY LIMITED. AS WELL, CERTAIN INFECTIOUS AGENTS IDENTIFIED IN THE PATHOGENESIS OF PBC MAY ALSO PLAY A ROLE IN THE PATHOGENESIS OF RA. THESE DATA SUGGEST THAT ALTHOUGH RA IS NOT SIGNIFICANTLY PRESENT IN PBC, SOME INDIVIDUALS WITH CERTAIN GENETIC TRAITS AND ENVIRONMENTAL EXPOSURES MAY DEVELOP BOTH CONDITIONS. THIS CONCEPT MAY ALSO APPLY TO OTHER CONCOMITANT DISEASES FOUND IN PBC PATIENTS. 2012 4 2588 33 EPIGENETICS OF PRIMARY BILIARY CHOLANGITIS. PRIMARY BILIARY CHOLANGITIS (PBC) IS A CHRONIC CHOLESTATIC LIVER DISEASE WITH NON-SUPPURATIVE DESTRUCTION OF THE INTRAHEPATIC BILE DUCTS. THE INTERPLAY OF GENETICS AND ENVIRONMENTAL TRIGGERS CONTRIBUTES TO THE ONSET OF THE DISEASE AND SUBSEQUENTLY RESULTS IN CHOLESTASIS AND PROGRESSIVE FIBROSIS. RECENTLY, GENOME-WIDE ASSOCIATION STUDIES (GWAS) HAVE IDENTIFIED MULTIPLE GENES INFLUENCING THE SUSCEPTIBILITY TO PBC IN HLA AND NON-HLA LOCI. HOWEVER, IT IS ESTIMATED THAT THE KNOWN RISK VARIANTS MERELY ACCOUNT FOR NO MORE THAN 20% OF THE HERITABILITY OF PBC AND CAUSES OF THE REMAINING HERITABILITY REMAIN UNCERTAIN. INCREASING EVIDENCE SUGGESTS THAT THE PRESENCE OF EPIGENETIC ABNORMALITIES MAY EXPLAIN THE "MISSING HERITABILITY" THAT CANNOT BE CAPTURED BY GWAS. AMONG THESE EPIGENETIC MECHANISMS, DNA METHYLATION, HISTONE MODIFICATION, AND NONCODING RNAS (I.E. MIRNA AND LNCRNA) ARE INVOLVED IN THE PATHOGENESIS OF PBC. ADDITIONALLY, TELOMERE DYSREGULATION IN BILIARY EPITHELIAL CELLS (BECS) MAY PLAY A ROLE IN DISEASE ONSET, WHEREAS A DEFICIENCY IN SEX CHROMOSOME AND SKEWED GENE EXPRESSION IN THE X CHROMOSOME MAY TO SOME EXTENT EXPLAIN THE FEMALE DOMINANCE IN PBC. 2020 5 5222 28 PRIMARY BILIARY CIRRHOSIS: FAMILY STORIES. PRIMARY BILIARY CIRRHOSIS (PBC) IS A CHRONIC IMMUNE-MEDIATED CHOLESTATIC LIVER DISEASE OF UNKNOWN AETIOLOGY WHICH AFFECTS MOSTLY WOMEN IN MIDDLE AGE. FAMILIAL PBC IS WHEN PBC AFFECTS MORE THAN ONE MEMBER OF THE SAME FAMILY, AND DATA SUGGEST THAT FIRST-DEGREE RELATIVES OF PBC PATIENTS HAVE AN INCREASED RISK OF DEVELOPING THE DISEASE. MOST OFTEN, THESE FAMILIAL CLUSTERS INVOLVE MOTHER-DAUGHTER PAIRS, WHICH IS CONSISTENT WITH THE FEMALE PREPONDERANCE OF THE DISEASE. THESE CLUSTERS PROVIDE EVIDENCE TOWARDS A GENETIC BASIS UNDERLYING PBC. HOWEVER, CLUSTERS OF NONRELATED INDIVIDUALS HAVE ALSO BEEN REPORTED, GIVING STRENGTH TO AN ENVIRONMENTAL COMPONENT. TWIN STUDIES HAVE DEMONSTRATED A HIGH CONCORDANCE FOR PBC IN MONOZYGOTIC TWINS AND A LOW CONCORDANCE AMONG DIZYGOTIC TWINS. IN CONCLUSION, STUDIES OF PBC IN FAMILIES CLEARLY DEMONSTRATE THAT GENETIC, EPIGENETIC, AND ENVIRONMENTAL FACTORS PLAY A ROLE IN THE DEVELOPMENT OF THE DISEASE. 2011 6 5221 26 PRIMARY BILIARY CHOLANGITIS: PATHOGENESIS AND THERAPEUTIC OPPORTUNITIES. PRIMARY BILIARY CHOLANGITIS IS A CHRONIC, SEROPOSITIVE AND FEMALE-PREDOMINANT INFLAMMATORY AND CHOLESTATIC LIVER DISEASE, WHICH HAS A VARIABLE RATE OF PROGRESSION TOWARDS BILIARY CIRRHOSIS. SUBSTANTIAL PROGRESS HAS BEEN MADE IN PATIENT RISK STRATIFICATION WITH THE GOAL OF PERSONALIZED CARE, INCLUDING EARLY ADOPTION OF NEXT-GENERATION THERAPY WITH LICENSED USE OF OBETICHOLIC ACID OR OFF-LABEL FIBRATE DERIVATIVES FOR THOSE WITH INSUFFICIENT BENEFIT FROM URSODEOXYCHOLIC ACID, THE CURRENT FIRST-LINE DRUG. THE DISEASE BIOLOGY SPANS GENETIC RISK, EPIGENETIC CHANGES, DYSREGULATED MUCOSAL IMMUNITY AND ALTERED BILIARY EPITHELIAL CELL FUNCTION, ALL OF WHICH INTERACT AND ARISE IN THE CONTEXT OF ILL-DEFINED ENVIRONMENTAL TRIGGERS. A CURRENT FOCUS OF RESEARCH ON NUCLEAR RECEPTOR PATHWAY MODULATION THAT SPECIFICALLY AND POTENTLY IMPROVES BILIARY EXCRETION, REDUCES INFLAMMATION AND ATTENUATES FIBROSIS IS REDEFINING THERAPY. PATIENTS ARE BENEFITING FROM PHARMACOLOGICAL AGONISTS OF FARNESOID X RECEPTOR AND PEROXISOME PROLIFERATOR-ACTIVATED RECEPTORS. IMMUNOTHERAPY REMAINS A CHALLENGE, WITH A LACK OF TARGET DEFINITION, PLEIOTROPIC IMMUNE PATHWAYS AND AN INTERPLAY BETWEEN HEPATIC IMMUNE RESPONSES AND CHOLESTASIS, WHEREIN BILE ACID-INDUCED INFLAMMATION AND FIBROSIS ARE DOMINANT CLINICALLY. THE MANAGEMENT OF PATIENT SYMPTOMS, PARTICULARLY PRURITUS, IS A NOTABLE GOAL REFLECTED IN THE DEVELOPMENT OF RATIONAL THERAPY WITH APICAL SODIUM-DEPENDENT BILE ACID TRANSPORTER INHIBITORS. 2020 7 6269 23 THE NEXT CHALLENGE IN PEDIATRIC CHOLESTASIS: DECIPHERING THE PATHOGENESIS OF BILIARY ATRESIA. CHOLESTASIS IS A COMMON PRESENTING SYMPTOM OF LIVER DISEASE IN INFANTS. CHIEF AMONG DISEASES PRESENTING AS NEONATAL CHOLESTASIS IS BILIARY ATRESIA, THE MOST COMMON CAUSE OF CHRONIC LIVER DISEASE IN CHILDREN, BUT LITTLE IS KNOWN ABOUT THE PATHOGENESIS OF THIS DISEASE. IN SEARCH FOR THE MOLECULAR BASIS OF BILIARY ATRESIA, WE BEGAN TWO AREAS OF INVESTIGATION. IN THE FIRST, WE INTERROGATED THE HEPATIC TRANSCRIPTOME OF CHILDREN WITH BILIARY ATRESIA AND FOUND AN INTERFERON-GAMMA (IFNGAMMA)-RICH PROINFLAMMATORY FOOTPRINT AT THE TIME OF DIAGNOSIS. TO DIRECTLY EXPLORE IF IFNGAMMA PLAYS AN IMPORTANT ROLE IN BILIARY INJURY AND OBSTRUCTION, WE USED A MOUSE MODEL OF EXPERIMENTAL BILIARY ATRESIA AND FOUND THAT INACTIVATION OF THE MURINE IFNGAMMA GENE DECREASES THE TROPISM OF LYMPHOCYTES TO NEONATAL BILE DUCTS AND PREVENTS THE INFLAMMATORY OBSTRUCTION OF THE DUCT LUMEN. FURTHER ANALYSIS OF THE EXTRAHEPATIC BILIARY TRACT ALSO OUTLINED A BROADER NETWORK OF PROINFLAMMATORY GENES AT THE ONSET AND DURING PROGRESSION TO DUCT OBSTRUCTION, WITH THE TIME-SPECIFIC ACTIVATION OF IFNGAMMA-, APOPTOSIS-, AND COMPLEMENT-DRIVEN NETWORKS. IN THE SECOND APPROACH, WE SEARCHED FOR MOLECULAR PROFILES THAT DIFFERENTIATE CLINICAL FORMS OF BILIARY ATRESIA BY ANALYZING THE HEPATIC TRANSCRIPTOME OF AGE-MATCHED SUBJECTS AT THE TIME OF DIAGNOSIS. WE FOUND A PRELIMINARY PROFILE THAT DIFFERENTIATES THE EMBRYONIC FROM THE PERINATAL FORMS OF BILIARY ATRESIA. THE PROFILE CONTAINED THE DIFFERENTIAL ACTIVATION OF GENES INVOLVED IN EPIGENETIC MECHANISMS OF DISEASE. COLLECTIVELY, THESE STUDIES PROVIDE NEW INSIGHT INTO PATHOGENESIS OF BILIARY ATRESIA AND IDENTIFY POTENTIAL THERAPEUTIC TARGETS TO FOSTER LONG-TERM OUTCOME WITH THE NATIVE LIVER. 2006 8 4472 33 MOLECULAR PATHOGENESIS OF CHOLANGIOCARCINOMA. BACKGROUND: CHOLANGIOCARCINOMAS ARE A HETEROGENEOUS GROUP OF MALIGNANCIES ARISING FROM A NUMBER OF CELLS OF ORIGIN ALONG THE BILIARY TREE. ALTHOUGH MOST CASES IN WESTERN COUNTRIES ARE SPORADIC, LARGE POPULATION-BASED STUDIES HAVE IDENTIFIED A NUMBER OF RISK FACTORS. THIS REVIEW SUMMARISES THE EVIDENCE BEHIND REPORTED RISK FACTORS AND CURRENT UNDERSTANDING OF THE MOLECULAR PATHOGENESIS OF CHOLANGIOCARCINOMA, WITH A FOCUS ON INFLAMMATION AND CHOLESTASIS AS THE DRIVING FORCES IN CHOLANGIOCARCINOMA DEVELOPMENT. RISK FACTORS FOR CHOLANGIOCARCINOGENESIS: CHOLESTATIC LIVER DISEASES (E.G. PRIMARY SCLEROSING CHOLANGITIS AND FIBROPOLYCYSTIC LIVER DISEASES), LIVER CIRRHOSIS, AND BILIARY STONE DISEASE ALL INCREASE THE RISK OF CHOLANGIOCARCINOMA. CERTAIN BACTERIAL, VIRAL OR PARASITIC INFECTIONS SUCH AS HEPATITIS B AND C AND LIVER FLUKES ALSO INCREASE CHOLANGIOCARCINOMA RISK. OTHER RISK FACTORS INCLUDE INFLAMMATORY DISORDERS (SUCH AS INFLAMMATORY BOWEL DISEASE AND CHRONIC PANCREATITIS), TOXINS (E.G. ALCOHOL AND TOBACCO), METABOLIC CONDITIONS (DIABETES, OBESITY AND NON-ALCOHOLIC FATTY LIVER DISEASE) AND A NUMBER OF GENETIC DISORDERS. MOLECULAR PATHOGENESIS OF CHOLANGIOCARCINOMA: REGARDLESS OF AETIOLOGY, MOST RISK FACTORS CAUSE CHRONIC INFLAMMATION OR CHOLESTASIS. CHRONIC INFLAMMATION LEADS TO INCREASED EXPOSURE OF CHOLANGIOCYTES TO THE INFLAMMATORY MEDIATORS INTERLEUKIN-6, TUMOUR NECROSIS FACTOR-A, CYCLO-OXYGENASE-2 AND WNT, RESULTING IN PROGRESSIVE MUTATIONS IN TUMOUR SUPPRESSOR GENES, PROTO-ONCOGENES AND DNA MISMATCH-REPAIR GENES. ACCUMULATING BILE ACIDS FROM CHOLESTASIS LEAD TO REDUCED PH, INCREASED APOPTOSIS AND ACTIVATION OF ERK1/2, AKT AND NF-KAPPAB PATHWAYS THAT ENCOURAGE CELL PROLIFERATION, MIGRATION AND SURVIVAL. OTHER MEDIATORS UPREGULATED IN CHOLANGIOCARCINOMA INCLUDE TRANSFORMING GROWTH FACTOR-BETA, VASCULAR ENDOTHELIAL GROWTH FACTOR, HEPATOCYTE GROWTH FACTOR AND SEVERAL MICRORNAS. INCREASED EXPRESSION OF THE CELL SURFACE RECEPTOR C-MET, THE GLUCOSE TRANSPORTER GLUT-1 AND THE SODIUM IODIDE SYMPORTER LEAD TO TUMOUR GROWTH, ANGIOGENESIS AND CELL MIGRATION. STROMAL CHANGES ARE ALSO OBSERVED, RESULTING IN ALTERATIONS TO THE EXTRACELLULAR MATRIX COMPOSITION AND RECRUITMENT OF FIBROBLASTS AND MACROPHAGES THAT CREATE A MICROENVIRONMENT PROMOTING CELL SURVIVAL, INVASION AND METASTASIS. CONCLUSION: REGARDLESS OF AETIOLOGY, MOST RISK FACTORS FOR CHOLANGIOCARCINOMA CAUSE CHRONIC INFLAMMATION AND/OR CHOLESTASIS, LEADING TO THE ACTIVATION OF COMMON INTRACELLULAR PATHWAYS THAT RESULT IN REACTIVE CELL PROLIFERATION, GENETIC/EPIGENETIC MUTATIONS AND CHOLANGIOCARCINOGENESIS. AN UNDERSTANDING OF THE MOLECULAR PATHOGENESIS OF CHOLANGIOCARCINOMA IS VITAL WHEN DEVELOPING NEW DIAGNOSTIC BIOMARKERS AND TARGETED THERAPIES FOR THIS DISEASE. 2019 9 5285 26 PROPROTEIN CONVERTASE SUBTILISIN/KEXIN TYPE 9 (PCSK9) IN THE BRAIN AND RELEVANCE FOR NEUROPSYCHIATRIC DISORDERS. PROPROTEIN CONVERTASE SUBTILISIN/KEXIN TYPE 9 (PCSK9) HAS LONG BEEN STUDIED IN THE LIVER DUE TO ITS REGULATION OF PLASMA LOW-DENSITY LIPOPROTEIN CHOLESTEROL (LDL-C) AND ITS CAUSAL ROLE IN FAMILIAL HYPERCHOLESTEROLEMIA. ALTHOUGH PCSK9 WAS FIRST DISCOVERED IN CEREBELLAR NEURONS UNDERGOING APOPTOSIS, ITS FUNCTION IN THE CENTRAL NERVOUS SYSTEM (CNS) IS LESS CLEAR. PCSK9 HAS BEEN SHOWN TO BE INVOLVED IN NEURONAL DIFFERENTIATION, LDL RECEPTOR FAMILY METABOLISM, APOPTOSIS, AND INFLAMMATION IN THE BRAIN, BUT IN VITRO AND IN VIVO STUDIES OFFER CONTRADICTORY FINDINGS. PCSK9 EXPRESSION IN THE ADULT BRAIN IS LOW BUT IS HIGHLY UPREGULATED DURING DISEASE STATES. CEREBRAL SPINAL FLUID (CSF) PCSK9 CONCENTRATIONS ARE CORRELATED WITH NEURAL TUBE DEFECTS AND NEURODEGENERATIVE DISEASES IN HUMAN PATIENTS. EPIGENETIC STUDIES REVEAL THAT CHRONIC ALCOHOL USE MAY MODULATE METHYLATION OF THE PCSK9 GENE AND GENETIC STUDIES SHOW THAT PATIENTS WITH GAIN-OF-FUNCTION PCSK9 VARIANTS HAVE HIGHER LDL-C AND AN INCREASED RISK OF ISCHEMIC STROKE. EARLY SAFETY STUDIES OF THE PCSK9 INHIBITORS EVOLOCUMAB AND ALIROCUMAB, USED TO TREAT HYPERCHOLESTEROLEMIA, HINTED THAT PCSK9 INHIBITION MAY NEGATIVELY IMPACT COGNITION BUT MORE RECENT, LONGER-TERM CLINICAL TRIALS FOUND NO ADVERSE NEUROCOGNITIVE EVENTS. THE PURPOSE OF THIS REVIEW IS TO ELUCIDATE THE ROLE OF PCSK9 IN THE BRAIN, PARTICULARLY ITS ROLE IN DISEASE PATHOGENESIS. 2020 10 6650 32 UPDATE ON ETIOLOGY AND PATHOGENESIS OF BILIARY ATRESIA. BILIARY ATRESIA IS A RARE INFLAMMATORY SCLEROSING OBSTRUCTIVE CHOLANGIOPATHY THAT INITIATES IN INFANCY AS COMPLETE CHOLEDOCHAL BLOCKAGE AND PROGRESSES TO THE INVOLVEMENT OF INTRAHEPATIC BILIARY EPITHELIUM. GROWING EVIDENCE SHOWS THAT BILIARY ATRESIA IS NOT A SINGLE ENTITY WITH A SINGLE ETIOLOGY BUT A PHENOTYPE RESULTING FROM MULTIFACTORIAL EVENTS WHOSE COMMON PATH IS OBLITERATIVE CHOLANGIOPATHY. THE ETIOLOGY OF BILIARY ATRESIA HAS BEEN EXPLAINED AS RESULTING FROM GENETIC VARIANTS, TOXINS, VIRAL INFECTION, CHRONIC INFLAMMATION OR BILE DUCT LESIONS MEDIATED BY AUTOIMMUNITY, ABNORMALITIES IN THE DEVELOPMENT OF THE BILE DUCTS, AND DEFECTS IN EMBRYOGENESIS, ABNORMAL FETAL OR PRENATAL CIRCULATION AND SUSCEPTIBILITY FACTORS. IT IS INCREASINGLY EVIDENT THAT THE GENETIC AND EPIGENETIC PREDISPOSITION COMBINED WITH THE ENVIRONMENTAL FACTORS TO WHICH THE MOTHER IS EXPOSED ARE POTENTIAL TRIGGERS FOR BILIARY ATRESIA. THERE IS ALSO AN INDICATION THAT A PROGRESSIVE THICKENING OF THE ARTERIAL MIDDLE LAYER OCCURS IN THIS DISEASE, SUGGESTIVE OF VASCULAR REMODELING AND DISAPPEARANCE OF THE INTERLOBULAR BILE DUCTS. IT IS SUGGESTED THAT THE HYPOXIA/ISCHEMIA PROCESS CAN AFFECT PORTAL STRUCTURES IN BILIARY ATRESIA AND IS ASSOCIATED WITH BOTH THE EXTENT OF BILIARY PROLIFERATION AND THE THICKENING OF THE MEDIAL LAYER. 2022 11 4257 18 METHYLOMIC PROFILING AND REPLICATION IMPLICATES DEREGULATION OF PCSK9 IN ALCOHOL USE DISORDER. ALCOHOL USE DISORDER (AUD) IS A COMMON AND CHRONIC DISORDER WITH SUBSTANTIAL EFFECTS ON PERSONAL AND PUBLIC HEALTH. THE UNDERLYING PATHOPHYSIOLOGY IS POORLY UNDERSTOOD BUT STRONG EVIDENCE SUGGESTS SIGNIFICANT ROLES OF BOTH GENETIC AND EPIGENETIC COMPONENTS. GIVEN THAT ALCOHOL AFFECTS MANY ORGAN SYSTEMS, WE PERFORMED A CROSS-TISSUE AND CROSS-PHENOTYPIC ANALYSIS OF GENOME-WIDE METHYLOMIC VARIATION IN AUD USING SAMPLES FROM 3 DISCOVERY, 4 REPLICATION, AND 2 TRANSLATIONAL COHORTS. WE IDENTIFIED A DIFFERENTIALLY METHYLATED REGION IN THE PROMOTER OF THE PROPROTEIN CONVERTASE SUBTILISIN/KEXIN 9 (PCSK9) GENE THAT WAS ASSOCIATED WITH DISEASE PHENOTYPES. BIOLOGICAL VALIDATION SHOWED THAT PCSK9 PROMOTER METHYLATION IS CONSERVED ACROSS TISSUES AND POSITIVELY CORRELATED WITH EXPRESSION. REPLICATION IN AUD DATASETS CONFIRMED PCSK9 HYPOMETHYLATION AND A TRANSLATIONAL MOUSE MODEL OF AUD SHOWED THAT ALCOHOL EXPOSURE LEADS TO PCSK9 DOWNREGULATION. PCSK9 IS PRIMARILY EXPRESSED IN THE LIVER AND REGULATES LOW-DENSITY LIPOPROTEIN CHOLESTEROL (LDL-C). OUR FINDING OF ALCOHOL-INDUCED EPIGENETIC REGULATION OF PCSK9 REPRESENTS ONE OF THE UNDERLYING MECHANISMS BETWEEN THE WELL-KNOWN EFFECTS OF ALCOHOL ON LIPID METABOLISM AND CARDIOVASCULAR RISK, WITH LIGHT ALCOHOL USE GENERALLY BEING PROTECTIVE WHILE CHRONIC HEAVY USE HAS DETRIMENTAL HEALTH OUTCOMES. 2018 12 1131 18 COMPREHENSIVE CIRCULAR RNA EXPRESSION PROFILING WITH ASSOCIATED CERNA NETWORK REVEALS THEIR THERAPEUTIC POTENTIAL IN CHOLESTEATOMA. CHOLESTEATOMA IS A CHRONIC DISEASE THAT PATHOLOGICALLY DISPLAYS A BENIGN TUMOR WITH EXCESSIVE SQUAMOUS EPITHELIAL CELL PROLIFERATION IN THE MIDDLE EAR. CLINICALLY, HOWEVER, IT CAN MANIFEST MALIGNANT BEHAVIOR BY DESTROYING ADJACENT TISSUES AND ORGANS. ALTHOUGH PREVIOUS STUDIES HAVE DEMONSTRATED THAT THE PATHOGENESIS OF CHOLESTEATOMA IS CORRELATED WITH EPIGENETIC DYSREGULATION, THE EXACT MECHANISM REMAINS UNCLEAR. CIRCULAR RNAS (CIRCRNAS) HAVE BEEN REVEALED AS BEING ABUNDANTLY EXPRESSED IN VARIOUS ORGANISMS AND HAVE BEEN FOUND TO CONTRIBUTE TO THE REGULATION OF MANY DISEASES. TO DATE, NO REPORTS HAVE ELUCIDATED THEIR EXPRESSION PROFILES AND FUNCTIONS IN CHOLESTEATOMA. IN THE PRESENT STUDY, THE CIRCRNA EXPRESSION PROFILE IN CHOLESTEATOMA WAS EXPLORED FOR THE FIRST TIME BY USING MICROARRAY ANALYSIS. WE OBTAINED A TOTAL OF 355 SIGNIFICANTLY DIFFERENTIALLY EXPRESSED CIRCRNAS IN CHOLESTEATOMA, AMONG WHICH 101 WERE IDENTIFIED TO BE UPREGULATED AND 254 DOWNREGULATED. BY CONSTRUCTING CIRCRNA?LNCRNA?MIRNA?MRNA COMPETING ENDOGENOUS RNA (CERNA) NETWORK, IT WAS DISCOVERED THAT CIRCRNAS MAY FUNCTION AS CERNAS AND CONTRIBUTE TO THE FORMATION OF CHOLESTEATOMA. THESE RESULTS PROVIDE NOVEL INSIGHT INTO THE PATHOGENESIS OF CHOLESTEATOMA AND SUGGEST CIRCRNAS AS POTENTIAL PROMISING THERAPEUTIC TARGETS FOR CHOLESTEATOMA. 2020 13 5146 35 POTENTIAL ROLES FOR INFECTIOUS AGENTS IN THE PATHOPHYSIOLOGY OF PRIMARY BILIARY CIRRHOSIS: WHAT'S NEW? PRIMARY BILIARY CIRRHOSIS (PBC) IS A PROGRESSIVE CHOLESTATIC LIVER DISEASE SEROLOGICALLY CHARACTERIZED BY THE PRESENCE OF HIGH-TITER ANTIMITOCHONDRIAL ANTIBODIES AND, HISTOLOGICALLY BY CHRONIC NONSUPPURATIVE CHOLANGITIS AND GRANULOMATA. THE AETIOLOGY OF THE DISEASE REMAINS ELUSIVE, ALTHOUGH GENETIC, EPIGENETIC, ENVIRONMENTAL, AND INFECTIOUS FACTORS HAVE BEEN CONSIDERED IMPORTANT FOR THE INDUCTION OF THE DISEASE IN GENETICALLY PRONE INDIVIDUALS. THE DISEASE SHOWS A STRIKING FEMALE PREDOMINANCE AND BECOMES CLINICALLY OVERT AT THE FOURTH TO SIXTH DECADE. THESE CHARACTERISTICS HAVE PROMPTED INVESTIGATORS TO CONSIDER INFECTIONS THAT PREDOMINATE IN WOMEN AT THESE AGES AS THE LIKELY CANDIDATES FOR TRIGGERING THE DISEASE. RECURRENT URINARY TRACT INFECTIONS DUE TO ESCHERICHIA COLI WERE THE FIRST INFECTIONS TO BE CONSIDERED PATHOGENETICALLY RELEVANT. OVER THE YEARS, SEVERAL OTHER MICROORGANISMS HAVE BEEN LINKED TO THE PATHOGENESIS OF PBC OWING TO EPIDEMIOLOGICAL, IMMUNOLOGICAL, MICROBIOLOGICAL, OR EXPERIMENTAL FINDINGS IN ANIMAL MODELS. RECENT STUDIES HAVE PROVIDED DATA SUPPORTING THE PATHOGENIC ROLE OF NOVOSPHINGOBIUM AROMATICIVORANS AND BETARETROVIRUSES. SEVERAL REPORTS HAVE LINKED OTHER ORGANISMS TO THE INDUCTION OF THE DISEASE AND/OR THE MAINTENANCE OF THE AUTO-AGGRESSIVE RESPONSES THAT ARE PERPETUATED OVER THE COURSE OF THE DISEASE. THIS REVIEW HIGHLIGHTS THE FINDINGS OF THE MOST RECENT STUDIES INVESTIGATING THE LINK BETWEEN INFECTIONS AND PBC. WE ALSO DISCUSS THE CLOSE INTERPLAY OF THE INFECTIOUS AGENTS WITH OTHER ENVIRONMENTAL AND GENETIC FACTORS, WHICH MAY EXPLAIN THE MULTIFACETED NATURE OF THIS PUZZLING DISEASE. 2013 14 4326 28 MICRORNAS IN THE PATHOGENESIS OF NONALCOHOLIC FATTY LIVER DISEASE. NONALCOHOLIC FATTY LIVER DISEASE (NAFLD), OR, MORE ACCURATELY, METABOLIC ASSOCIATED FATTY LIVER DISEASE, ACCOUNTS FOR A LARGE PROPORTION OF CHRONIC LIVER DISORDERS WORLDWIDE AND IS CLOSELY ASSOCIATED WITH OTHER CONDITIONS SUCH AS CARDIOVASCULAR DISEASE, OBESITY, AND TYPE 2 DIABETES MELLITUS. NAFLD RANGES FROM SIMPLE STEATOSIS TO NONALCOHOLIC STEATOHEPATITIS (NASH) AND CAN PROGRESS TO CIRRHOSIS AND, EVENTUALLY, ALSO HEPATOCELLULAR CARCINOMA. THE MORBIDITY AND MORTALITY ASSOCIATED WITH NAFLD ARE INCREASING RAPIDLY YEAR ON YEAR. CONSEQUENTLY, THERE IS AN URGENT NEED TO UNDERSTAND THE ETIOLOGY AND PATHOGENESIS OF NAFLD AND IDENTIFY EFFECTIVE THERAPEUTIC TARGETS. MICRORNAS (MIRNAS), IMPORTANT EPIGENETIC FACTORS, HAVE RECENTLY BEEN PROPOSED TO PARTICIPATE IN NAFLD PATHOGENESIS. HERE, WE REVIEW THE ROLES OF MIRNAS IN LIPID METABOLISM, INFLAMMATION, APOPTOSIS, FIBROSIS, HEPATIC STELLATE CELL ACTIVATION, INSULIN RESISTANCE, AND OXIDATIVE STRESS, KEY FACTORS THAT CONTRIBUTE TO THE OCCURRENCE AND PROGRESSION OF NAFLD. ADDITIONALLY, WE SUMMARIZE THE ROLE OF MIRNA-ENRICHED EXTRACELLULAR VESICLES IN NAFLD. THESE MIRNAS MAY COMPRISE SUITABLE THERAPEUTIC TARGETS FOR THE TREATMENT OF THIS CONDITION. 2021 15 2936 32 GENETIC AND EPIGENETIC ABNORMALITIES IN PRIMARY SCLEROSING CHOLANGITIS-ASSOCIATED CHOLANGIOCARCINOMA. PRIMARY SCLEROSING CHOLANGITIS (PSC) IS A CHOLESTATIC LIVER DISEASE OF UNKNOWN ETIOLOGY, CHARACTERIZED BY CHRONIC INFLAMMATION OF THE BILIARY TREE WITH SUBSEQUENT FIBROSIS AND CIRRHOSIS OF THE LIVER. PATIENTS WITH PSC ARE AT INCREASED RISK FOR THE DEVELOPMENT OF CHOLANGIOCARCINOMA (CCA), A HIGHLY MALIGNANT EPITHELIAL TUMOR ARISING FROM THE INTRAHEPATIC AND EXTRAHEPATIC BILE DUCTS. CURRENTLY, ORTHOTOPIC LIVER TRANSPLANTATION IS THE ONLY CURATIVE TREATMENT. THE LACK OF EFFICIENT DIAGNOSTIC METHODS FOR EARLY DETECTION AND THE LIMITED THERAPEUTIC OPTIONS FOR CCA ARE MAJOR PROBLEMS AND ARE ASSOCIATED WITH POOR SURVIVAL. THE PATHOGENESIS OF PSC-ASSOCIATED CCA IS COMPLEX AND POORLY UNDERSTOOD. IT SEEMS THAT PRO-INFLAMMATORY CYTOKINES PLAY AN IMPORTANT ROLE IN GENETIC AND EPIGENETIC CHANGES THAT CONTRIBUTE TO THE CARCINOGENIC PROCESS. THE MAPPING OF GENETIC ALTERATIONS MAY ELUCIDATE MOLECULAR TARGETS THAT MAY BE APPLIED AS BIOMARKERS TO FACILITATE EARLY DIAGNOSIS OF MALIGNANT DEGENERATION TO IMPROVE PATIENT OUTCOME. IN THE LAST DECADE, THE INTRODUCTION OF SEVERAL NOVEL MOLECULAR TECHNIQUES AVAILABLE FOR GENOME-WIDE SCREENING HAS ADVANCED OUR KNOWLEDGE ON MANY OF THE GENETIC ABNORMALITIES THAT ARE PREVALENT IN CCA AND PSC-ASSOCIATED CCA. THIS REVIEW SUMMARIZES GENETIC AND EPIGENETIC ABNORMALITIES, WHICH HAVE IMPORTANT POTENTIAL FOR CLINICAL APPLICATION. 2013 16 3112 34 GEOEPIDEMIOLOGY AND (EPI-)GENETICS IN PRIMARY BILIARY CHOLANGITIS. PRIMARY BILIARY CHOLANGITIS (PBC) IS A RARE FEMALE PREPONDERANT CHRONIC AUTOIMMUNE CHOLESTATIC LIVER DISEASE, CHARACTERIZED BY INTRAHEPATIC DUCTOPENIA AND PROGRESSIVE FIBROSIS. DURING LAST DECADES INCIDENCE AND PREVALENCE SHOWED AN INCREASING RATE WHICH VARY WIDELY WORLDWIDE DEMONSTRATING AN IMPORTANT INTERACTION BETWEEN ENVIRONMENTAL AND GENETIC FACTORS. HERITABILITY SUGGESTED BY FAMILIAL OCCURRENCE AND MONOZYGOTIC TWINS CONCORDANCE HAVE BEEN CONFIRMED IN MORE STUDIES. EPIGENETICS MECHANISMS SUCH AS HISTONE MODIFICATION AND DNA METHYLATION CAN PARTIALLY EXPLAIN PREDISPOSITION AND INHERITANCE OF THIS DISEASE. NEVERTHELESS, AN ASSOCIATION WITH SPECIFIC CLASS II HUMAN LEUKOCYTE ANTIGEN (HLA) VARIANTS HAVE BEEN REPORTED, SHOWING AN INCREASE RISK IN SUSCEPTIBILITY. MORE RECENTLY, DATA REGARDING A STRONG PROTECTIVE ASSOCIATION BETWEEN PBC AND HLA ALLELES CONFIRMED THIS ASSOCIATION. AFTER RECENT GENOME-WIDE ASSOCIATION STUDIES (GWAS), A MORE INTRICATE INTERACTION BETWEEN PBC AND THE HLA REGION HAS BEEN SHOWN. FURTHERMORE, GWAS ALSO IDENTIFIED SEVERAL IMMUNE-RELATED-GENES IMPLICATED. MORE GENOME-WIDE ASSOCIATION STUDIES ON THIS DISEASE ARE NEEDED TO REACH A COMPLETE AND SYSTEMATIC KNOWLEDGE OF THIS DISEASE. IN THIS REVIEW WE DISCUSS MORE RECENT ISSUED DATA ON GEOEPIDEMIOLOGY OF PBC AND THE ROLE OF (EPI-)GENETIC MECHANISMS IN ITS PATHOGENESIS. 2018 17 3608 20 IN SEARCH FOR GENES RELATED TO ATHEROSCLEROSIS AND DYSLIPIDEMIA USING ANIMAL MODELS. ATHEROSCLEROSIS IS A MULTIFACTORIAL CHRONIC DISEASE THAT AFFECTS LARGE ARTERIES AND MAY LEAD TO FATAL CONSEQUENCES. ACCORDING TO CURRENT UNDERSTANDING, INFLAMMATION AND LIPID ACCUMULATION ARE THE TWO KEY MECHANISMS OF ATHEROSCLEROSIS DEVELOPMENT. ANIMAL MODELS BASED ON GENETICALLY MODIFIED MICE HAVE BEEN DEVELOPED TO INVESTIGATE THESE ASPECTS. ONE SUCH MODEL IS LOW-DENSITY LIPOPROTEIN (LDL) RECEPTOR KNOCKOUT (KO) MICE (LDLR(-/-)), WHICH ARE CHARACTERIZED BY A MODERATE INCREASE OF PLASMA LDL CHOLESTEROL LEVELS. ANOTHER WIDELY USED GENETICALLY MODIFIED MOUSE STRAIN IS APOLIPOPROTEIN-E KO MICE (APOE(-/-)) THAT LACKS THE PRIMARY LIPOPROTEIN REQUIRED FOR THE UPTAKE OF LIPOPROTEINS THROUGH THE HEPATIC RECEPTORS, LEADING TO EVEN GREATER PLASMA CHOLESTEROL INCREASE THAN IN LDLR(-/-) MICE. THESE AND OTHER ANIMAL MODELS ALLOWED FOR CONDUCTING GENETIC STUDIES, SUCH AS GENOME-WIDE ASSOCIATION STUDIES, MICROARRAYS, AND GENOTYPING METHODS, WHICH HELPED IDENTIFYING MORE THAN 100 MUTATIONS THAT CONTRIBUTE TO ATHEROSCLEROSIS DEVELOPMENT. HOWEVER, TRANSLATION OF THE RESULTS OBTAINED IN ANIMAL MODELS FOR HUMAN SITUATIONS WAS SLOW AND CHALLENGING. AT THE SAME TIME, GENETIC STUDIES CONDUCTED IN HUMANS WERE LIMITED BY LOW SAMPLE SIZES AND HIGH HETEROGENEITY IN PREDICTIVE SUBCLINICAL PHENOTYPES. IN THIS REVIEW, WE SUMMARIZE THE CURRENT KNOWLEDGE ON THE USE OF KO MICE FOR IDENTIFICATION OF GENES IMPLICATED IN ATHEROSCLEROSIS AND PROVIDE A LIST OF GENES INVOLVED IN ATHEROSCLEROSIS-ASSOCIATED INFLAMMATORY PATHWAYS AND THEIR BRIEF CHARACTERISTICS. MOREOVER, WE DISCUSS THE APPROACHES FOR CANDIDATE GENE SEARCH IN ANIMALS AND HUMANS AND DISCUSS THE PROGRESS MADE IN THE FIELD OF EPIGENETIC STUDIES THAT APPEAR TO BE PROMISING FOR IDENTIFICATION OF NOVEL BIOMARKERS AND THERAPEUTIC TARGETS. 2020 18 5807 22 STRATEGIES, MODELS AND BIOMARKERS IN EXPERIMENTAL NON-ALCOHOLIC FATTY LIVER DISEASE RESEARCH. NON-ALCOHOLIC FATTY LIVER DISEASE ENCOMPASSES A SPECTRUM OF LIVER DISEASES, INCLUDING SIMPLE STEATOSIS, STEATOHEPATITIS, LIVER FIBROSIS AND CIRRHOSIS AND HEPATOCELLULAR CARCINOMA. NON-ALCOHOLIC FATTY LIVER DISEASE IS CURRENTLY THE MOST DOMINANT CHRONIC LIVER DISEASE IN WESTERN COUNTRIES DUE TO THE FACT THAT HEPATIC STEATOSIS IS ASSOCIATED WITH INSULIN RESISTANCE, TYPE 2 DIABETES MELLITUS, OBESITY, METABOLIC SYNDROME AND DRUG-INDUCED INJURY. A VARIETY OF CHEMICALS, MAINLY DRUGS, AND DIETS IS KNOWN TO CAUSE HEPATIC STEATOSIS IN HUMANS AND RODENTS. EXPERIMENTAL NON-ALCOHOLIC FATTY LIVER DISEASE MODELS RELY ON THE APPLICATION OF A DIET OR THE ADMINISTRATION OF DRUGS TO LABORATORY ANIMALS OR THE EXPOSURE OF HEPATIC CELL LINES TO THESE DRUGS. MORE RECENTLY, GENETICALLY MODIFIED RODENTS OR ZEBRAFISH HAVE BEEN INTRODUCED AS NON-ALCOHOLIC FATTY LIVER DISEASE MODELS. CONSIDERABLE INTEREST NOW LIES IN THE DISCOVERY AND DEVELOPMENT OF NOVEL NON-INVASIVE BIOMARKERS OF NON-ALCOHOLIC FATTY LIVER DISEASE, WITH SPECIFIC FOCUS ON HEPATIC STEATOSIS. EXPERIMENTAL DIAGNOSTIC BIOMARKERS OF NON-ALCOHOLIC FATTY LIVER DISEASE, SUCH AS (EPI)GENETIC PARAMETERS AND '-OMICS'-BASED READ-OUTS ARE STILL IN THEIR INFANCY, BUT SHOW GREAT PROMISE. IN THIS PAPER, THE ARRAY OF TOOLS AND MODELS FOR THE STUDY OF LIVER STEATOSIS IS DISCUSSED. FURTHERMORE, THE CURRENT STATE-OF-ART REGARDING EXPERIMENTAL BIOMARKERS SUCH AS EPIGENETIC, GENETIC, TRANSCRIPTOMIC, PROTEOMIC AND METABONOMIC BIOMARKERS WILL BE REVIEWED. 2015 19 4598 15 NATURAL PRODUCTS: THE ROLE AND MECHANISM IN LOW-DENSITY LIPOPROTEIN OXIDATION AND ATHEROSCLEROSIS. ATHEROSCLEROSIS IS A CHRONIC INFLAMMATORY, METABOLIC, AND EPIGENETIC DISEASE, WHICH LEADS TO THE LIFE-THREATENING CORONARY ARTERY DISEASE. EMERGING STUDIES FROM BENCH TO BEDSIDE HAVE DEMONSTRATED THE PIVOTAL ROLE OF LOW-DENSITY LIPOPROTEIN (LDL) OXIDATION IN THE INITIATION AND PROGRESSION OF ATHEROSCLEROSIS. THIS ARTICLE HEREBY REVIEWS OXIDATION MECHANISM OF LDL, AND THE PRO-ATHEROGENIC AND BIOMARKER ROLE OF OXIDIZED LDL IN ATHEROSCLEROSIS. WE ALSO REVIEW THE PHARMACOLOGICAL EFFECTS OF SEVERAL REPRESENTATIVE NATURAL PRODUCTS (VITAMIN E, RESVERATROL, QUERCETIN, PROBUCOL, TANSHINONE IIA, EPIGALLOCATECHIN GALLATE, AND LYCOPENE) IN PROTECTING AGAINST LDL OXIDATION AND ATHEROSCLEROSIS. CLINICAL AND BASIC RESEARCH SUPPORTS THE BENEFICIAL EFFECTS OF THESE NATURAL PRODUCTS IN INHIBITING LDL OXIDATION AND PREVENTING ATHEROSCLEROSIS, BUT THE DATA ARE STILL CONTROVERSIAL. THIS MAY BE RELATED TO FACTORS SUCH AS THE POPULATION AND THE DOSAGE AND TIME OF TAKING NATURAL PRODUCTS INVOLVED IN DIFFERENT STUDIES. UNDERSTANDING THE MECHANISM OF LDL OXIDATION AND EFFECT OF OXIDIZED LDL HELP RESEARCHERS TO FIND NOVEL THERAPIES AGAINST ATHEROSCLEROSIS. 2021 20 5366 22 RECENT ADVANCES IN LEAN NAFLD. AS THE PREDOMINANT TYPE OF CHRONIC LIVER DISEASE, THE GROWING PREVALENCE OF NONALCOHOLIC FATTY LIVER DISEASE (NAFLD) HAS BECOME A CONCERN WORLDWIDE. ALTHOUGH OBESITY PLAYS THE MOST PIVOTAL ROLE IN NAFLD, APPROXIMATELY 10-20% OF INDIVIDUALS WITH NAFLD WHO ARE NOT OVERWEIGHT OR OBESE (BMI < 25 KG/M2, OR BMI < 23 KG/M2 IN ASIANS) HAVE "LEAN NAFLD." LEAN INDIVIDUALS WITH NAFLD HAVE A LOWER PREVALENCE OF DIABETES, HYPERTENSION, HYPERTRIGLYCERIDEMIA, CENTRAL OBESITY, AND METABOLIC SYNDROME THAN NONLEAN INDIVIDUALS WITH NAFLD, BUT HIGHER FIBROSIS SCORES AND RATES OF CARDIOVASCULAR MORBIDITY AND ALL-CAUSE MORTALITY IN ADVANCED STAGES. THE PATHOPHYSIOLOGICAL MECHANISMS OF LEAN NAFLD REMAIN POORLY UNDERSTOOD. STUDIES HAVE SHOWN THAT LEAN NAFLD IS MORE CORRELATED WITH FACTORS SUCH AS ENVIRONMENTAL, GENETIC SUSCEPTIBILITY, AND EPIGENETIC REGULATION. THIS REVIEW WILL EXAMINE THE WAY IN WHICH THE RESEARCH PROGRESS AND CHARACTERISTIC OF LEAN NAFLD, AND EXPLORE THE FUNCTION OF EPIGENETIC MODIFICATION TO PROVIDE THE BASIS FOR THE CLINICAL TREATMENT AND DIAGNOSIS OF LEAN NAFLD. 2022