Role of PNPLA3 in Hepatic Stellate Cells and Hepatic Cellular Crosstalk.

AIMS: Since its discovery, the patatin-like phospholipase domain containing 3 (PNPLA3) (rs738409 C>G p.I148M) variant has been studied extensively to unravel its molecular function. Although several studies proved a causal relationship between the PNPLA3 I148M variant and MASLD development and particularly fibrosis, the pathological mechanisms promoting this phenotype have not yet been fully clarified. METHODS: We summarise the latest data regarding the PNPLA3 I148M variant in hepatic stellate cells (HSCs) activation and macrophage biology or the path to inflammation-induced fibrosis. RESULTS: Elegant but contradictory studies have ascribed PNPLA3 a hydrolase or an acyltransferase function. The PNPLA3 I148M results in hepatic lipid accumulation, which predisposes the hepatocyte to lipotoxicity and lipo-apoptosis, producing DAMPs, cytokines and chemokines leading to recruitment and activation of macrophages and HSCs, propagating fibrosis. Recent studies showed that the PNPLA3 I148M variant alters HSCs biology via attenuation of PPARγ, AP-1, LXRα and TGFß activity and signalling. CONCLUSIONS: The advent of refined techniques in isolating HSCs has made PNPLA3's direct role in HSCs for liver fibrosis development more apparent. However, many other mechanisms still need detailed investigations.

The effect of dulaglutide on glycated hemoglobin is associated with PNPLA3 Ι148Μ gene polymorphism in patients with type 2 diabetes mellitus.

PURPOSE: The evaluation of the effect of dulaglutide on glycated hemoglobin (HbA1c) and non-invasive indices of hepatic steatosis among different genotypes of the PNPLA3 I148M (rs738409) and CETP Taq1B (rs708272) polymorphisms in patients with type 2 diabetes mellitus (T2DM) and non-alcoholic fatty liver disease (NAFLD). METHODS: Relevant data from patients with inadequately controlled T2DM, also displaying NAFLD, administered 1.5 mg dulaglutide weekly for 6 months were retrospectively retrieved. The non-invasive indices, fatty liver index (FLI) and hepatic steatosis index (HSI), were calculated. Genotyping for rs738409 and rs708272 were performed with polymerase chain reaction. RESULTS: Data from 80 patients (39 females), aged 64.4 ± 9.5 years and displaying a baseline BMI of 34.5 ± 5.8 kg/m2, were retrieved at baseline and after 6 months (endpoint) of dulaglutide treatment. Glycated hemoglobin (HbA1c; -0.72 ± 1.10%; p < 0.001), FLI (-5.8 ± 9.8; p < 0.001) and HSI (-1.18 ± 3.51; p = 0.004) significantly decreased after treatment. Lipid profile and liver function tests also improved after treatment. Overall, homozygotes for the reference rs738409 allele (CC) displayed a 2.4-fold decrease (p = 0.002) and heterozygotes (CG) an 1.6-fold decrease (p = 0.013) compared to GG homozygotes after treatment, but the effect was largely limited to female patients. No similar effect was observed in FLI, HSI and other relevant parameters. No association was observed between rs708272 and any of the parameters studied. CONCLUSIONS: rs738409, but not rs708272, was associated with the effect of dulaglutide on HbA1c, but not on presumed hepatic steatosis or other relevant parameters. Sex-specific effects were also noticed.

PNPLA3 variation and kidney disease.

Accumulating epidemiological evidence shows that the patatin-like phospholipase domain-containing protein-3 (PNPLA3) rs738409 G allele, which is the most robust genetic variant associated with greater susceptibility to metabolic dysfunction-associated steatotic liver disease (MASLD), is significantly associated with impaired kidney function in both adults and children, regardless of the presence of common renal risk factors, MASLD severity, and other potential confounders. Although some prospective studies have reported a significant association between the PNPLA3 rs738409 G allele and the increased risk of developing chronic kidney disease (CKD), the epidemiological evidence about a possible direct effect of the PNPLA3 rs738409 G allele on the risk of developing CKD is still limited. Experimentally, PNPLA3 is expressed in renal podocytes, pericytes, and proximal tubule cells, thus supporting the notion that the mutant PNPLA3 protein may play a role in developing renal steatosis and fibrosis. However, it cannot be ruled out that a part of the adverse effect of the PNPLA3 rs738409 G allele on kidney function may be driven by a direct impact of this genetic variant on the development and progression of MASLD. It is possible to hypothesize that identifying the PNPLA3 genotype might help identify individuals at higher risk of CKD and those at greater risk of advanced MASLD. In this narrative minireview, we summarize the current epidemiological data about the association between the PNPLA3 rs738409 G allele and the risk of CKD and abnormal albuminuria. We also briefly discuss the putative biological mechanisms underpinning this association and its potential and future clinical implications.

A study of genetic variants, genetic risk score and DNA methylation of PNPLA3 and TM6SF2 in alcohol liver cirrhosis.

BACKGROUND: Genetic and epigenetic factors are associated with the development of alcohol-associated liver disease (AALD). The single nucleotide polymorphisms (SNPs), rs738409 in Patatin-like phospholipase domain-containing protein (PNPLA3) and rs58542926 in Transmembrane 6 Superfamily Member 2 (TM6SF2) are strongly associated with AALD in different global populations, Hence, we analyzed the genetic risk score for these variants and deoxyribonucleic acid (DNA) methylation levels of the PNPLA3 and TM6SF2 genes among cases (alcohol liver cirrhosis) and controls (heavy drinkers without cirrhosis). METHOD: We studied patients with alcohol use disorder (AUD) with cirrhosis (AUD-C + ve, n = 136) and without cirrhosis (AUD-C-ve, n = 107) drawn from the clinical services of St. John's Medical College Hospital (SJMCH) (Gastroenterology and Psychiatry) and Centre for Addiction Medicine (CAM), National Institute of Mental Health and Neurosciences, (NIMHANS). Genotype data was generated for rs738409 (PNPLA3) and rs58542926 (TM6SF2) and used to calculate unweighted genetic risk score (uGRS) and weighted genetic risk scores (wGRS). DNA methylation levels were estimated by pyrosequencing at PNPLA3 and TM6SF2 loci. RESULTS: Overall we observed a significantly higher genetic risk score (weighted genetic risk score, wGRS) in individuals with alcohol use disorder compared to control population (p = < 0.01). Further, uGRS and wGRS were associated with the diagnosis of cirrhosis, even after correcting for age of onset, quantity and frequency of drinking. We also found hypomethylation at CpG2 of TM6SF2 gene in AUD-C + ve compared to AUD-C-ve (P = 0.02). CONCLUSION: We found that a genetic risk score based on SNPs in the PNPLA3 and TM6SF2 genes was significantly associated with cirrhosis in patients with AUD, suggesting a potential utility in identifying patients at risk and providing pre-emptive interventions. These may include interventions that aim to alter DNA methylation, which may be one of the mechanisms through which elevated genetic risk may influence the development of cirrhosis.

Polimorfismo no gene PNPLA3 e o consumo de carne vermelha aumentam o risco de fibrose em pacientes com DHGNA comprovado por biópsia em acompanhamento médico em um centro terciário no Sudoeste do Brasil / Pnpla3 gene polymorphism and red meat consumption increased fibrosis risk in nash biopsy-proven patients under medical follow-up in a tertiary center in southwest brazil

ABSTRACT Background: Recent studies show an increase in nonalcoholic fatty liver disease (NAFLD) in populations with higher consumption of red meat, processed and cooked at high temperatures. On the other hand, the single nucleotide polymorphism rs738409 in the Patatin-like phospholipase domain containing 3 (PNPLA3) gene has been implicated in susceptibility to NAFLD and liver fibrosis. However, the synergistic effect between red meat consumption and the PNPLA3 gene polymorphism in NAFLD has not yet been evaluated. Objective: To evaluate the association between the presence of the polymorphism in the PNPLA3 gene and the consumption of macronutrients, including meat consumption and its cooking method among NAFLD patients. Methods: This was a cross-sectional study with 91 patients diagnosed with NAFLD by liver biopsy with genotyping for the polymorphism in the PNPLA3 gene were included. The consumption of calories and macronutrients was verified using the semi-quantitative food frequency questionnaire and the specific questionnaire on meat consumption. PNPLA3 gene polymorphism was analyzed by real-time polymerase chain reaction (RT-PCR) and anthropometric evaluation was realized. Results: The mean BMI was 32.38±4.58 kg/m² and the waist circumference was 107±10 cm. On liver biopsy, 42% of patients had significant fibrosis (F≥2). The odds ratio of F≥2 was 2.12 for the GG group and 1.54 for the CG group, compared to the CC group. The mean caloric intake was 1170±463.20 kcal/d. The odds ratio in the CC group concerning high red meat consumption in comparison to low consumption was 1.33. For white meat, the odds ratio was 0.8 when comparing high and low intake, also in the CC group. Conclusion: High red meat intake and PNPLA3 gene polymorphism seem to synergistically affect NAFLD and liver fibrosis, requiring confirmation in a larger number of patients and in different populations.

RESUMO Contexto: Estudos recentes mostram um aumento da doença hepática gordurosa não alcoólica (DHGNA) em populações com maior consumo de carne vermelha, processada e cozida em altas temperaturas. Por outro lado, o polimorfismo rs738409 no gene Patatin-like fosfolipase contendo 3 (PNPLA3) tem sido implicado na suscetibilidade à DHGNA e fibrose hepática. No entanto, o efeito sinérgico entre o consumo de carne vermelha e o polimorfismo no gene PNPLA3 na DHGNA ainda não foi avaliado. Objetivo: Avaliar a associação entre a presença do polimorfismo no gene PNPLA3 e o consumo de macronutrientes, incluindo o consumo de carne e seu modo de cozimento em pacientes com DHGNA. Métodos: Realizamos um estudo transversal com 91 pacientes diagnosticados com DHGNA por biópsia hepática e genotipados para o polimorfismo no gene PNPLA3. O consumo de calorias e macronutrientes foi verificado por meio do questionário de frequência alimentar semi-quantitativo (QFA) e do questionário específico sobre consumo de carnes. O polimorfismo no gene PNPLA3 foi analisado por reação em cadeia da polimerase em tempo real (RT-PCR) e a avaliação antropométrica foi realizada. Resultados: O índice de massa corporal médio foi de 32,38±4,58 kg/m² e a circunferência da cintura foi de 107±10 cm. Na biópsia hepática, 42% dos pacientes apresentavam fibrose significativa (F≥2). O odds ratio de F≥2 foi de 2,12 para o grupo GG e 1,54 para o grupo GC, comparado ao grupo CC. A ingestão calórica média foi de 1.170±463,20 kcal/d. O odds ratio para alto consumo de carne vermelha no grupo CC em comparação ao baixo consumo foi de 1,33. Para a carne branca, este valor foi de 0,8 ao comparar o alto e o baixo consumo, também no grupo CC. Conclusão: A alta ingestão de carne vermelha e o polimorfismo no gene PNPLA3 parecem afetar sinergicamente a DHGNA e a fibrose hepática, necessitando de confirmação em maior número de pacientes e em diferentes populações.

NAFLD in Polycystic Ovary Syndrome: Association with PNPLA3 and Metabolic Features.

Background: The aim of this study was to determine the frequency of the rs738409 polymorphism in the patatin-like phospholipase domain containing 3 (PNPLA3) gene in patients with polycystic ovary syndrome (PCOS) and its impact on nonalcoholic fatty liver disease (NAFLD) risk and severity. We also evaluated other risk factors associated with NAFLD and advanced fibrosis. Methods: This was a cross-sectional study involving 163 patients with PCOS at a tertiary center. Genotyping for the PNPLA3 polymorphism was undertaken using a TaqMan assay. The degree of fibrosis was defined by transient elastography. Results: The prevalence of NAFLD was 72.4%, and the polymorphism was heterozygous in 41.7% and homozygous in 8% of patients. Homeostasis model assessment of insulin resistance ≥ 2.5 was the main factor associated with the risk of developing NAFLD (OR = 4.313, p = 0.022), and its effect was amplified by the polymorphism (OR = 12.198, p = 0.017). Age > 32 years also conferred a higher risk for NAFLD. HDL values ≥ 50 mg/dL conferred protection against the outcome. Metabolic syndrome (OR = 13.030, p = 0.020) and AST > 32 U/L (OR = 9.039, p = 0.009) were independent risk factors for advanced fibrosis. Conclusions: In women with PCOS, metabolic characteristics are more relevant than PNPLA3 polymorphism regarding the risk for NAFLD and its advanced forms, but these factors can act synergistically, increasing disease risk.

Lysosomal Acid Lipase Activity in Non-alcoholic Fatty Liver Disease as a Novel Diagnostic and Therapeutic Target: A Systematic Literature Review of Current Evidence and Future Directions.

Background and aim: Non-alcoholic fatty liver disease (NAFLD) presents with the accumulation of excessive intra-hepatic fat without significant alcohol intake. Multifactorial pathogenesis is reported to be involved. Reduced lysosomal acid lipase (LAL) activity is suggested as one of the novel-involved pathogenic mechanisms. This review summarizes the available evidence on the role of LAL activity in NAFLD pathogenesis. Methods: Four databases namely, PubMed/Medline, Science direct, Cochrane Library, and Google scholar were searched to identify relevant observational records evaluating the role of LAL activity in the pathogenesis of NAFLD. All studies were assessed for their quality by using Newcastle-Ottawa Scale or The Joanna Briggs Institute Critical Appraisal tools for cohort and cross-sectional studies, respectively. The estimates of LAL activity and other clinical outcomes were expressed as mean (SD) and number (%) as presented in the primary studies. Results: A total of nine good quality studies with 1711 patients with NAFLD and 877 controls from different groups (healthy volunteers, alcoholics, cryptogenic cirrhosis, and HCV-positive) were included. From the NAFLD group, 59.55% were males and the overall mean age ranged between the studies from 12.6 ± 8.5 months in pediatrics to 58.90 ± 13.82 years in adults. In the NAFLD group, the LAL activity varied from 0.53 ± 0.08 to 1.3 ± 0.70 (nmol/spot/hr) between the studies which was less than all control groups except cryptogenic cirrhosis patients (0.5 ± 0.15 nmol/spot/hr). Of the other outcomes of interest, ALT, AST, total cholesterol, triglyceride, and LDL cholesterol were found elevated in NAFLD patients than in controls. Conclusion: The current evidence suggests a potential correlation of reduced LAL activity with NAFLD pathogenesis according to its severity. Large-scale studies are recommended, more importantly in patients with NAFLD having no metabolic or genetic involvement. Further LAL can act as a new non-invasive diagnostic biomarker to identify that specific NAFLD subgroup.

Pathogenesis of Alcohol-Associated Liver Disease.

Excessive alcohol consumption is a global healthcare problem with enormous social, economic, and clinical consequences. While chronic, heavy alcohol consumption causes structural damage and/or disrupts normal organ function in virtually every tissue of the body, the liver sustains the greatest damage. This is primarily because the liver is the first to see alcohol absorbed from the gastrointestinal tract via the portal circulation and second, because the liver is the principal site of ethanol metabolism. Alcohol-induced damage remains one of the most prevalent disorders of the liver and a leading cause of death or transplantation from liver disease. Despite extensive research on the pathophysiology of this disease, there are still no targeted therapies available. Given the multifactorial mechanisms for alcohol-associated liver disease pathogenesis, it is conceivable that a multitherapeutic regimen is needed to treat different stages in the spectrum of this disease.

Public Health Measures and Prevention of Alcohol-Associated Liver Disease.

Hazardous alcohol consumption causes approximately 4% of deaths globally, constituting one of the leading risk factors for the burden of the disease worldwide. Alcohol has several health consequences, such as alcohol-associated liver disease, hepatocellular carcinoma, nonliver neoplasms, physical injury, cardiac disease, and psychiatric disorders. Alcohol misuse significantly affects workforce productivity, with elevated direct and indirect economic costs. Due to the high impact of alcohol consumption on the population, public health has led to the development of a range of strategies to reduce its harmful effects. Regulatory public health policies (PHP) for alcohol can exist at the global, regional, international, national, or subnational levels. Effective strategies incorporate a multilevel, multicomponent approach, targeting multiple determinants of drinking and alcohol-related harms. The World Health Organization categorizes the PHP into eight categories: national plan to fight the harmful consequences of alcohol, national license and production and selling control, taxes control and pricing policies, limiting drinking age, restrictions on alcohol access, driving-related alcohol policies, control over advertising and promotion, and government monitoring systems. These policies are supported by evidence from different populations, demonstrating that determinants of alcohol use depend on several factors such as socioeconomic level, age, sex, ethnicity, production, availability, marketing, and others. Although most policies have a significant individual effect, a higher number of PHP are associated with a lower burden of disease due to alcohol. The excessive consequences of alcohol constitute a call for action, and clinicians should advocate for developing and implementing a new PHP on alcohol consumption.

Association of rs738409 Polymorphism in Adiponutrin Gene with Liver Steatosis and Atherosclerosis Risk Factors in Greek Children and Adolescents.

Non-alcoholic fatty liver disease (NAFLD) shares several risk factors with atherosclerosis, as it is associated with components of the metabolic syndrome. However, genetic variations have also been linked to the risk of NAFLD, such as adiponutrin/patatin-like phospholipase domain-containing the protein 3 (PNPLA3) rs738409 polymorphism. The aim of the study was to determine the associations of thePNPLA3 rs738409 polymorphism with NAFLD and atherosclerosis risk factors in children and adolescents from northern Greece. A total of 91 children/adolescents who followed a Mediterranean eating pattern with no particular restrictions were studied. They were divided into three subgroups, according to their body mass index (BMI) and the presence or absence of liver disease. Diagnosis of NAFLD was based on a liver ultrasound, while the distribution of the PNPLA3 rs738409 polymorphism was investigated in all the participants. From the components of metabolic syndrome, only BMI, waist circumference, blood pressure, and the homeostasis model of insulin resistance (HOMA-IR) differed significantly between groups. The rs738409 polymorphism was significantly associated with BMI and NAFLD, while lipid values had no significant association with either NAFLD or gene polymorphism. This study shows that in Greekchildren, there is a significant association between the rs738409polymorphism in the PNPLA3 gene and hepatic steatosis, regardless of bodyweight.

Low skeletal muscle mass is associated with more severe histological features of non-alcoholic fatty liver disease in male.

BACKGROUND/PURPOSE OF THE STUDY: Although low skeletal muscle mass is associated with non-alcoholic fatty liver disease (NAFLD), it is currently uncertain whether there are associations between weight-adjusted appendicular skeletal muscle (ASM%), severity of histological features of NAFLD, and the patatin-like phospholipase domain-containing 3 (PNPLA3) rs738409 polymorphism. Our aim was to test for a possible influence of the PNPLA3 rs738409 variant on the association between ASM% and severity of NAFLD histological features. METHODS: We enrolled 401 Chinese male with biopsy-proven NAFLD. Using a bioelectrical-impedance body composition analyzer (BIA, Inbody 720, Japan Inc., Tokyo), we calculated the ASM% as the percentage of total appendicular skeletal muscle mass (ASM, kg)/total body mass (kg) × 100. RESULTS: Compared to those with high ASM%, patients with low ASM% (≤ 30.6, i.e., the median value of distribution of the whole sample) had a greater severity of individual histological features of NAFLD. These patients also had a higher risk of severe steatosis and non-alcoholic steatohepatitis (NASH) (adjusted-odds ratio [OR] 2.34, 95% CI 1.39-3.93, and adjusted-OR 2.22, 95% CI 1.30-3.77) even after adjusting for age, body mass index, diabetes, and serum creatinine levels. Carriage of the G allele of PNPLA3 rs738409 plus low ASM% was associated with a higher risk of severe steatosis and presence of liver fibrosis (OR 3.02, 95% CI 1.46-6.26, p = 0.003 and OR 2.18, 95% CI 1.03-4.60, p = 0.041 respectively), and there was a non-significant but borderline increased risk of NASH (OR 2.00, 95% CI 0.98-4.06, p = 0.056). CONCLUSIONS: Low ASM% and the presence of a G allele within PNPLA3 rs738409 is associated with more severe histological features of NAFLD.

Characterization and Pharmacological Validation of a Preclinical Model of NASH in Göttingen Minipigs.

Background: Nonalcoholic fatty liver disease (NAFLD) is the leading cause of chronic liver disease, which is associated with features of metabolic syndrome. NAFLD may progress in a subset of patients into nonalcoholic steatohepatitis (NASH) with liver injury resulting ultimately in cirrhosis and potentially hepatocellular carcinoma. Today, there is no approved treatment for NASH due to, at least in part, the lack of preclinical models recapitulating features of human disease. Here, we report the development of a dietary model of NASH in the Göttingen minipig. Methods: First, we performed a longitudinal characterization of diet-induced NASH and fibrosis using biochemical, histological, and transcriptional analyses. We then evaluated the pharmacological response to Obeticholic acid (OCA) treatment for 8 weeks at 2.5mg/kg/d, a dose matching its active clinical exposure. Results: Serial histological examinations revealed a rapid installation of NASH driven by massive steatosis and inflammation, including evidence of ballooning. Furthermore, we found the progressive development of both perisinusoidal and portal fibrosis reaching fibrotic septa after 6 months of diet. Histological changes were mechanistically supported by well-defined gene signatures identified by RNA Seq analysis. While treatment with OCA was well tolerated throughout the study, it did not improve liver dysfunction nor NASH progression. By contrast, OCA treatment resulted in a significant reduction in diet-induced fibrosis in this model. Conclusions: These results, taken together, indicate that the diet-induced NASH in the Göttingen minipig recapitulates most of the features of human NASH and may be a model with improved translational value to prioritize drug candidates toward clinical development.

The Risk of Cirrhosis and Its Complications Based on PNPLA3 rs738409 G Allele Frequency.

BACKGROUND: Data regarding the influence of patatin-like phospholipase domain-containing 3 (PNPLA3) polymorphism for patients with liver cirrhosis (LC) are scarce. OBJECTIVE: This study assesses the role of the PNPLA3 polymorphism for the development of LC and its complications by the findings of genetic examinations. METHODS: Patients with LC caused by virus (n = 157), alcohol (n = 104), nonalcoholic fatty liver disease (NAFLD) (n = 106), or autoimmune disease (n = 33) and without LC (n = 128) were enrolled. LC was composed of the presence and absence of complications, such as variceal bleeding, hepatic ascites, and hepatic encephalopathy. To assess the role of the PNPLA3 polymorphism, odds ratio (OR) for the rs738409 variant was calculated for the patients between (i) with LC and without LC in the entire cohort and (ii) the presence and absence of complications in the patients with LC. RESULTS: There was a significant difference among the patients without LC and those with alcohol, NAFLD-related LC in the frequency of G alleles (p < 0.001, both). According to complications of LC, the OR for NAFLD-related cirrhosis significantly increased in the presence of the two mutated alleles (OR = 3.165; p = 0.046) when the wild type was used as the reference. However, there were no significant risks for the complications in the virus and alcohol-related cirrhosis unless there was a presence of G alleles. CONCLUSION: The PNPLA3 polymorphism was associated with the risk of NAFLD-related LC and its complications.

Role of PNPLA3 in the Assessment and Monitoring of Hepatic Steatosis and Fibrosis in Patients with Chronic Hepatitis C Infection Who Achieved a Sustained Virologic Response.

Background and Objectives: Hepatic diseases are an important public health problem. All patients with chronic hepatitis C virus (HCV) infection receive treatment, regardless of hepatic fibrosis severity. However, evaluation of hepatic fibrosis and steatosis is still useful in assessing evolution, prognosis and monitoring of hepatic disease, especially after treatment with direct-acting antivirals (DAAs). The aim of this study was to assess the link between patatin-like phospholipase domain-containing 3 (PNPLA3) polymorphism and the degree of hepatic steatosis and fibrosis in patients with chronic HCV infection, as well as changes in steatosis and fibrosis three monthsafter obtaining a sustained viral response (SVR). Materials and Methods:Ourstudy included 100 patients with chronic hepatitis C (CHC) infection and compensated cirrhosis who received DAA treatment and who were evaluated using Fibromax prior to and 3 months after SVR. The influence of PNPLA3 (CC, CG, GG) genotype among these patients on the degree of post-treatment regression of steatosis and fibrosis was assessed. Results: Regression was noticed in the degree of both hepatic steatosis and hepatic fibrosis post-DAA treatment (three months after SVR). Analysis of the correlation between PNPLA3 genotype and fibrosis indicated that the average level of fibrosis (F) before DAA treatment was higher in patients with the GG genotype than in patients with the CC or CG genotype. Three months after SVR, the average level of fibrosis decreased; however, it remained significantly increased in GG subjects compared to that in CC or CG patients. The degree of hepatic steatosis before treatment was not significantly different among patients with different PNPLA3 genotypes, and no significant correlations were observed three months after SVR. Conclusions: The genetic variants of PNPLA3 influence the evolution of hepatic fibrosis. The GG subtype plays an important role in the degree of hepatic fibrosis both before and after treatment (three months after SVR)and could be a prognostic marker for assessment of post-SVR evolution.

3D disorganization and rearrangement of genome provide insights into pathogenesis of NAFLD by integrated Hi-C, Nanopore, and RNA sequencing.

The three-dimensional (3D) conformation of chromatin is integral to the precise regulation of gene expression. The 3D genome and genomic variations in non-alcoholic fatty liver disease (NAFLD) are largely unknown, despite their key roles in cellular function and physiological processes. High-throughput chromosome conformation capture (Hi-C), Nanopore sequencing, and RNA-sequencing (RNA-seq) assays were performed on the liver of normal and NAFLD mice. A high-resolution 3D chromatin interaction map was generated to examine different 3D genome hierarchies including A/B compartments, topologically associated domains (TADs), and chromatin loops by Hi-C, and whole genome sequencing identifying structural variations (SVs) and copy number variations (CNVs) by Nanopore sequencing. We identified variations in thousands of regions across the genome with respect to 3D chromatin organization and genomic rearrangements, between normal and NAFLD mice, and revealed gene dysregulation frequently accompanied by these variations. Candidate target genes were identified in NAFLD, impacted by genetic rearrangements and spatial organization disruption. Our data provide a high-resolution 3D genome interaction resource for NAFLD investigations, revealed the relationship among genetic rearrangements, spatial organization disruption, and gene regulation, and identified candidate genes associated with these variations implicated in the pathogenesis of NAFLD. The newly findings offer insights into novel mechanisms of NAFLD pathogenesis and can provide a new conceptual framework for NAFLD therapy.

Screening of Family Members of Nonalcoholic Fatty Liver Disease Patients can Detect Undiagnosed Nonalcoholic Fatty Liver Disease Among Them: Is There a Genetic Link?

BACKGROUND & AIMS: Nonalcoholic fatty liver disease (NAFLD) has multifactorial origin. Genetic and environmental factors lead to the biology of this complex disorder. In this study, we screened parents of cases with NAFLD and compared them with parents of cases without NAFLD to see its familial aggregation and the role of patatin-like phospholipase domain containing 3 (PNPLA3). METHOD: It was a cross-sectional study. Parents of probands with NAFLD and without NAFLD were screened with abdominal sonography, anthropometry, blood tests, transient elastography, and PNPLA3 polymorphism. RESULTS: We had enrolled 303 individuals: 51 probands with NAFLD, 50 probands without NAFLD, and their 202 parents. Parents of the NAFLD group had significantly higher metabolic risk factors as compared with parents of the non-NAFLD group. They had a significantly higher rate of fatty liver (P = 0.0001), mean serum aspartate aminotransferase levels (P = 0.011), mean serum alanine aminotransferase levels (P = 0.001),raised fasting and postprandial blood sugar levels, lower mean platelets (P = 0.033) and serum albumin levels (P = 0.005), and higher mean liver stiffness (P = 0.001) on transient elastography.Frequency of PNPLA3 polymorphism within NAFLD group was higher compared to the non-NAFLD group (mutant GG-13.3 vs 3.3%). Similarly, parents of NAFLD group had mutant GG in 15 % versus 5% in parents of non-NAFLD group, (P = 0.105, odds ratio 6), though it was not statistically significant but may be relevant. In this study, offsprings of parents with nonalcoholic steatohepatitis were likely to have GG homozygous allele. A NAFLD16 score based on parent's parameters was calculated to predict the probability of NAFLD occurrence in an overweight obese individual. CONCLUSION: Screening of parents of individuals with NAFLD will help in the identification of undiagnosed NAFLD cases and other metabolic risk factors among them as there is a familial aggregation of NAFLD. One can predict the occurrence of NAFLD in the next generation using the NAFLD16 score.

Murine Models of Alcohol Consumption: Imperfect but Still Potential Source of Novel Biomarkers and Therapeutic Drug Discovery for Alcoholic Liver Disease.

Animal models of liver disease are fundamentally important to strengthen our knowledge and understanding of human liver diseases. Murine models of alcohol consumption are utilized to investigate alcoholic liver injury to develop new therapeutic targets. The well accepted and commonly used murine models of chronic alcohol consumption are Meadows-Cook (MC) and Lieber-DeCarli (LD). LD model is based on an isocaloric high-fat liquid diet, but mice under the MC model fed on a regular chow diet with alcohol added to the drinking water. Alcoholic liver disease in real world is frequently diagnosed in patients with obesity and high fat intake, mirroring LD diet. The overlap of the specific effect of ethanol and obesity is difficult to differentiate by clinician and pathologist. In this commentary, we will further discuss our research findings comparing MC and LD as a tool to dissect early alcohol versus increased fat intake detrimental effects on the liver. The critical analysis of these two models could provide evidence to differentiate the specific impact of alcohol on the liver from the combined influence of alcohol and diet. Ultimately, these investigations could uncover potential biomarkers and therapeutic targets for personalized type of alcoholic liver injury.

Bile acids induced hepatic lipid accumulation in mice by inhibiting mRNA expression of patatin-like phospholipase domain containing 3 and microsomal triglyceride transfer protein.

Preliminary studies have shown that a lithogenic diet (LG), which contains cholesterol and cholic acid, induces gallstones and hepatic lipid accumulation (HLA), and reduction of blood triglyceride in mice. We hypothesized that an LG induces HLA by diminishing hepatic triglyceride excretion; however, there is no clear understanding of the mechanism of LG-induced HLA. This study aimed to investigate transcript expression related to the synthesis, expenditure, and efflux of hepatic triglyceride, in mice fed an LG for 4 weeks. Results showed lower plasma concentrations of triglyceride in the LG group than in the control group, but no symptoms of hepatic injury were observed. Hepatic mRNA expressions of patatin-like phospholipase domain containing 3 (Pnpla3), microsomal triglyceride transfer protein (Mttp), and acyl-CoA oxidase 1 (Acox1) were also reduced in the LG group. Deoxycholic acid and lithocholic acid promoted intracellular lipid accumulation, reduced triglyceride concentration in media, and suppressed expression of PNPLA3 and MTTP in HepG2 human hepatoma cells. These findings suggest that deoxycholic acid and lithocholic acid promote HLA by inhibiting the expression of PNPLA3, ACOX1, and MTTP that are involved in lipid metabolism.

Genetic predisposition similarities between NASH and ASH: Identification of new therapeutic targets.

Fatty liver disease can be triggered by a combination of excess alcohol, dysmetabolism and other environmental cues, which can lead to steatohepatitis and can evolve to acute/chronic liver failure and hepatocellular carcinoma, especially in the presence of shared inherited determinants. The recent identification of the genetic causes of steatohepatitis is revealing new avenues for more effective risk stratification. Discovery of the mechanisms underpinning the detrimental effect of causal mutations has led to some breakthroughs in the comprehension of the pathophysiology of steatohepatitis. Thanks to this approach, hepatocellular fat accumulation, altered lipid droplet remodelling and lipotoxicity have now taken centre stage, while the role of adiposity and gut-liver axis alterations have been independently validated. This process could ignite a virtuous research cycle that, starting from human genomics, through omics approaches, molecular genetics and disease models, may lead to the development of new therapeutics targeted to patients at higher risk. Herein, we also review how this knowledge has been applied to: a) the study of the main PNPLA3 I148M risk variant, up to the stage of the first in-human therapeutic trials; b) highlight a role of MBOAT7 downregulation and lysophosphatidyl-inositol in steatohepatitis; c) identify IL-32 as a candidate mediator linking lipotoxicity to inflammation and liver disease. Although this precision medicine drug discovery pipeline is mainly being applied to non-alcoholic steatohepatitis, there is hope that successful products could be repurposed to treat alcohol-related liver disease as well.

[Correlation between PNPLA3 rs738409 and TM6SF2 rs58542926 gene polymorphism and primary liver cancer in the Han Population of China's Northeast region].

Objective: To investigate the correlation between patatin-like phospholipase domain-containing 3 (PNPLA3) rs738409 and transmembrane 6 superfamily member 2 (TM6SF2) rs58542926 gene polymorphisms and the incidence of primary liver cancer in the Han population of China's Northeast region. Methods: A case-control study was used to enroll 521 patients with primary liver cancer as the case group and 164 healthy people as the control group. The case group was divided into groups with and without liver cirrhosis according to etiology. The polymerase chain reaction (PCR) method was used to detect the genetic polymorphisms of PNPLA3 rs738409 and TM6SF2 rs58542926, respectively. Results: Compared with the control group, the frequency distribution of PNPLA3 rs738409 G allele in the case group was significantly different (OR = 1.583, P = 0.001). Further grouping showed that there was no statistically significant difference between the control and hepatitis C-related liver cancer group (P = 0.161), but there were significant differences in other groups (P < 0.05). Compared with the control group, the frequency of TM6SF2 rs58542926 T allele in the case group was significantly higher than that in the control group (OR = 1.759, P = 0.048). After grouping, the frequency of CT/TT genotype in the liver cancer group combined with liver cirrhosis and the T allele frequency in the alcohol-related liver cancer group had statistically significant difference (P = 0.045 and 0.032, respectively) when compared with control group. The patients were divided into CG/GG group and CC group, and CT/TT group and CC group according to whether they carried PNPLA3 rs738409 G allele, and TM6SF2 rs58542926 T allele. Results showed that there were no statistically significant differences in liver enzyme indexes, albumin (ALB), total bilirubin (TBIL), alpha-fetoprotein (AFP) and fasting blood glucose between CG/GG group and CC group, and CT/TT group and CC group. The patients with liver cirrhosis in the case group were divided into≥7 groups and < 7 groups according to the Child-Pugh score. Results showed that there were no statistically significant difference in the Child-Pugh score between PNPLA3 rs738409 CG/GG group and CC group patients and TM6SF2 rs58542926 CT/TT group and CC group patients (P > 0.05). Conclusion: PNPLA3 rs738409 and TM6SF2 rs58542926 gene polymorphisms are correlated with the occurrence of primary liver cancer in the Han population of China's Northeast region. PNPLA3 rs738409 and TM6SF2 rs58542926 gene polymorphisms have no effect on indexes' such as liver enzymes, ALB, TBIL, AFP and FBS in primary liver cancer..