Gene-Environmental Interactions as Metabolic Drivers of Nonalcoholic Steatohepatitis.
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ABSTRACT:
SUBMITTER: Albhaisi S
PROVIDER: S-EPMC8142267 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:Obesity is associated with strong risks of development of chronic inflammatory liver disease and metabolic syndrome following a second hit. This study tests the hypothesis that free radical metabolism of low chronic exposure to bromodichloromethane (BDCM), a disinfection byproduct of drinking water, causes nonalcoholic steatohepatitis (NASH), mediated by cytochrome P450 isoform CYP2E1 and adipokine leptin. Using diet-induced obese mice (DIO), mice deficient in CYP2E1, and mice with spontaneous knockout of the leptin gene, we show that BDCM caused increased lipid peroxidation and increased tyrosine nitration in DIO mice, events dependent on reductive metabolism by CYP2E1. DIO mice, exposed to BDCM, exhibited increased hepatic leptin levels and higher levels of proinflammatory gene expression and Kupffer cell activation. Obese mice exposed to BDCM also showed profound hepatic necrosis, Mallory body formation, collagen deposition, and higher alpha smooth muscle actin expression, events that are hallmarks of NASH. The absence of CYP2E1 gene in mice that were fed with a high-fat diet did not show NASH symptoms and were also protected from hepatic metabolic alterations in Glut-1, Glut-4, phosphofructokinase and phosphoenolpyruvate carboxykinase gene expressions (involved in carbohydrate metabolism), and UCP-1, PGC-1?, SREBP-1c, and PPAR-? genes (involved in hepatic fat metabolism). Mice lacking the leptin gene were significantly protected from both NASH and metabolic alterations following BDCM exposure, suggesting that higher levels of leptin induction by BDCM in the liver contribute to the development of NASH and metabolic alterations in obesity. These results provide novel insights into BDCM-induced NASH and hepatic metabolic reprogramming and show the regulation of obesity-linked susceptibility to NASH by environmental factors, CYP2E1, and leptin.
| S-EPMC3707434 | biostudies-literature
Project description:The molecular mechanisms behind the transition from simple steatosis to nonalcoholic steatohepatitis (NASH) in nonalcoholic fatty liver disease (NAFLD) are not clearly understood. This hinders development of effective therapies for treatment and prevention of NASH. In this study expression profiling data from normal, steatosis, and NASH human livers were used to predict transcription factors that are misregulated as mechanistic features of NAFLD progression. Previously-published human NAFLD gene expression profiling data from normal, steatosis, and NASH livers were subjected to transcription factor binding site enrichment analysis. Selected transcription factors that bind enriched transcription factor binding sites were analyzed for changes in expression. Distinct transcription factor binding sites were enriched in genes significantly up- or down-regulated in NASH livers. Those enriched in up-regulated genes were bound by transcription factors such as FOXA, CEBP, and HNF1 family members, while those enriched in down-regulated genes were bound by nuclear receptors involved in xenobiotic sensing and lipid metabolism. Levels of mRNA and protein for selected transcription factors were significantly changed during disease progression. The study indicates that NAFLD progression involves changes in activity or expression of transcription factors that regulate genes involved in hepatic processes known to be altered in NASH. Transcription factors such as PPAR receptors, FoxA family members, and HNF4A might be targeted therapeutically to prevent NAFLD progression.
| S-EPMC5129657 | biostudies-literature
Project description:Nonalcoholic fatty liver disease (NAFLD) is the most common type of chronic liver disease in the Western countries, affecting up to 25% of the general population and becoming a major health concern in both adults and children. NAFLD encompasses the entire spectrum of fatty liver disease in individuals without significant alcohol consumption, ranging from nonalcoholic fatty liver (NAFL) to nonalcoholic steatohepatitis (NASH) and cirrhosis. NASH is a manifestation of the metabolic syndrome and hepatic disorders with the presence of steatosis, hepatocyte injury (ballooning), inflammation, and, in some patients, progressive fibrosis leading to cirrhosis. The pathogenesis of NASH is a complex process and implicates cell interactions between liver parenchymal and nonparenchymal cells as well as crosstalk between various immune cell populations in liver. Lipotoxicity appears to be the central driver of hepatic cellular injury via oxidative stress and endoplasmic reticulum (ER) stress. This review focuses on the contributions of hepatocytes and nonparenchymal cells to NASH, assessing their potential applications to the development of novel therapeutic agents. Currently, there are limited pharmacological treatments for NASH; therefore, an increased understanding of NASH pathogenesis is pertinent to improve disease interventions in the future.
| S-EPMC5086374 | biostudies-literature
Project description:ObjectiveNonalcoholic steatohepatitis (NASH) is increasingly common in obese patients. However, its metabolic consequences in patients with type 2 diabetes mellitus (T2DM) are unknown.Research design and methodsWe studied 154 obese patients divided in four groups: 1) control (no T2DM or NAFLD), 2) T2DM without NAFLD, 3) T2DM with isolated steatosis, and 4) T2DM with NASH. We evaluated intrahepatic triglycerides by proton MRS ((1)H-MRS) and assessed insulin secretion/resistance during an oral glucose tolerance test and a euglycemic-hyperinsulinemic clamp with glucose turnover measurements.ResultsNo significant differences among groups were observed in sex, BMI, or total body fat. Metabolic parameters worsened progressively with the presence of T2DM and the development of hepatic steatosis, with worse hyperinsulinemia, insulin resistance, and dyslipidemia (hypertriglyceridemia and low HDL cholesterol) in those with NASH (P < 0.001). Compared with isolated steatosis, NASH was associated with more dysfunctional and insulin-resistant adipose tissue (either as insulin suppression of plasma FFA [33 ± 3 vs. 48 ± 6%] or adipose tissue insulin resistance index [9.8 ± 1.0 vs. 5.9 ± 0.8 mmol/L ⋅ µIU/mL]; both P < 0.03). Furthermore, insulin suppression of plasma FFA correlated well with hepatic steatosis (r = -0.62; P < 0.001) and severity of steatohepatitis (rs = -0.52; P < 0.001). Hepatic insulin sensitivity was also more significantly impaired among patients with T2DM and NASH, both fasting and with increasing insulin levels within the physiological range (10 to 140 µIU/mL), compared with other groups.ConclusionsIn obese patients with T2DM, the presence of NAFLD is associated with more severe hyperinsulinemia, dyslipidemia, and adipose tissue/hepatic insulin resistance compared with patients without NAFLD. The unfavorable metabolic profile linked to NAFLD should prompt strategies to identify and treat this population early on.
| S-EPMC5864108 | biostudies-literature
Project description:Nonalcoholic hepatitis (NASH) is the progressive inflammatory form of nonalcoholic fatty liver disease. Although the mechanisms of hepatic inflammation in NASH remain incompletely understood, emerging literature implicates the proinflammatory environment created by toxic lipid-induced hepatocyte injury, termed lipotoxicity. Interestingly, numerous NASH-promoting kinases in hepatocytes, immune cells, and adipocytes are activated by the lipotoxic insult associated with obesity. In the current review, we discuss recent advances in NASH-promoting kinases as disease mediators and therapeutic targets. The focus of the review is mainly on the mitogen-activated protein kinases including mixed lineage kinase 3, apoptosis signal-regulating kinase 1, c-Jun N-terminal kinase, and p38 MAPK; the endoplasmic reticulum (ER) stress kinases protein kinase RNA-like ER kinase and inositol-requiring protein-1α; as well as the Rho-associated protein kinase 1. We also discuss various pharmacological agents targeting these stress kinases in NASH that are under different phases of development.
| S-EPMC7728626 | biostudies-literature
Project description:Non‑alcoholic steatohepatitis (NASH) is a pathological condition of the liver in which hepatocyte steatosis, invasion of inflammatory cells and hepatic injury occur without alcohol abuse. Despite the known risk of liver cancer and liver fibrosis that may progress to liver cirrhosis that exists with NASH, an understanding of related gene expression and associated functional changes remains insufficient. The present study used a mouse model of NASH induced by a high‑fat diet to examine gene expression in the liver and to search for transcripts that could predict early liver fibrosis in the future. Mice fed a high‑fat diet for 2 weeks showed typical NASH liver histology by hematoxylin and eosin staining, and increased fibrosis was confirmed by Sirius red staining after 6 weeks. Functional changes associated with liver damage, liver inflammation, liver steatosis and liver fibrosis were predicted by toxicological ontology analysis using Ingenuity Pathways Analysis. Downregulated microRNA (miR)‑21 and upregulated collagen type III α1 mRNA in the liver and upregulated exosomal miR‑21 in serum of mice fed a high‑fat diet for 1 and/or 2 weeks were confirmed by reverse transcription‑quantitative PCR, suggesting that these changes occur prior to histological confirmation of fibrosis. Therefore, it may be possible to predict future liver fibrosis by analyzing fibrosis‑related genes that shift prior to pathological findings.
| S-EPMC9727582 | biostudies-literature
Project description:Growth differentiation factor 15 (GDF15) is an endocrine hormone belonging to the TGF? superfamily member. GDF15 administration or GDF15 overexpression has been reported to have anti-obesity and anti-diabetic effects. Although non-alcoholic fatty liver disease (NAFLD)/non-alcoholic steatohepatitis (NASH) is frequently associated with obesity and insulin resistance, the functional role of endogenous GDF15 and therapeutic effect of GDF15 overexpression in NASH and related metabolic deterioration have not been evaluated. Here, we found that GDF15 expression was increased in the livers of NASH animal models and human subjects with NASH. Elevated expression of GDF15 was due to diet-induced hepatic endoplasmic reticulum (ER) stress. Gdf15-knockout mice exhibited aggravated NASH phenotypes such as increased steatosis, hepatic inflammation, fibrosis, liver injury, and metabolic deterioration. Furthermore, GDF15 directly suppressed expression of fibrosis-related genes and osteopontin (OPN), contributing factors for NASH-related fibrosis, in hepatic stellate cells in vitro and in the liver of mice in vivo. Finally, we found that GDF15-transgenic mice showed attenuation of NASH phenotypes and metabolic deterioration. Therefore, our results suggest that induction of endogenous GDF15 is a compensatory mechanism to protect against the progression of NASH and that GDF15 could be an attractive therapeutic candidate for treatment of NASH and NASH-related metabolic deterioration.
| S-EPMC5931608 | biostudies-literature
Project description:ContextNonalcoholic Fatty Liver Disease (NAFLD) is the major chronic liver disease in the pediatric population. NAFLD includes a broad spectrum of abnormalities (inflammation, fibrosis and cirrhosis), ranging from accumulation of fat (also known as steatosis) towards non-alcoholic steatohepatitis (NASH). The development of NAFLD in children is significantly increased.Evidence acquisitionA literature search of electronic databases was undertaken for the major studies published from 1998 to today. The databases searched were: PubMed, EMBASE, Orphanet, Midline and Cochrane Library. We used the key words: "non-alcoholic fatty liver disease, children, non-alcoholic steatohepatitis and fatty liver".ResultsNAFLD/NASH is probably promoted by "multiple parallel hits": environmental and genetic factors, systemic immunological disorders (oxidative stress, persistent-low grade of inflammation) as well as obesity and metabolic alterations (insulin resistance and metabolic syndrome). However its exact cause still underdiagnosed and unknown.ConclusionsPediatric NAFLD/NASH is emerging problem. Longitudinal follow-up studies, unfortunately still insufficient, are needed to better understand the natural history and outcome of NAFLD in children. This review focuses on the current knowledge regarding the epidemiology, pathogenesis, environmental, genetic and metabolic factors of disease. The review also highlights the importance of studying the underlying mechanisms of pediatric NAFLD and the need for complete and personalized approach in the management of NAFLD/NASH.
| S-EPMC4013495 | biostudies-literature
Project description:Background & aimsObese patients with nonalcoholic steatohepatitis (NASH) are at risk for cirrhosis if significant weight loss is not achieved. The single fluid-filled intragastric balloon (IGB) induces meaningful weight loss and might be used in NASH treatment. We performed an open-label prospective study to evaluate the effects of IGB placement on metabolic and histologic features of NASH.MethodsTwenty-one patients with early hepatic fibrosis (81% female; mean age, 54 years; average body mass index, 44 kg/m2) underwent magnetic resonance elastography (MRE) and endoscopic ultrasound with core liver biopsy collection at time IGB placement and removal at a single center from October 2016 through March 2018. The primary outcome measure was the changes in liver histology parameters after IGB, including change in nonalcoholic fatty liver disease activity score (NAS) and fibrosis score. We also evaluated changes in weight, body mass index, waist to hip ratio, aminotransaminases, fasting levels of lipids, fasting glucose, glycosylated hemoglobin, and MRE-detected liver stiffness.ResultsSix months after IGB, patients' mean total body weight loss was 11.7% ± 7.7%, with significant reductions in HbA1c (1.3% ± 0.5%) (P = .02). Waist circumference decreased by 14.4 ± 2.2 cm (P = .001). NAS improved in 18 of 20 patients (90%), with a median decrease of 3 points (range, 1-4 points); 16 of 20 patients (80%) had improvements of 2 points or more. Fibrosis improved by 1.17 stages in 15% of patients, and MRE-detected fibrosis improved by 1.5 stages in 10 of 20 patients (50%). Half of patients reached endpoints approved by the Food and Drug Administration of for NASH resolution and fibrosis improvement. Percent total body weight loss did not correlate with reductions in NAS or fibrosis. Other than post-procedural pain (in 5% of patients), no serious adverse events were reported.ConclusionIn a prospective study, IGB facilitated significant metabolic and histologic improvements in NASH. IGB appears to be safe and effective for NASH management when combined with a prescribed diet and exercise program. ClinicalTrials.gov no: NCT02880189.
| S-EPMC8106130 | biostudies-literature
Project description:Our objective is to determine the role of myeloid FoxO1 in regulating hepatic lipid metabolism and its contribution to nonalcoholic steatohepatitis (NASH) in mice. We generated mice with conditional FoxO1 depletion in myeloid cells, using the FoxO1-LoxP/LysM-Cre system. We then fed myeloid cell-conditional FoxO1-knockout and wild-type male mice a NASH-inducing diet for 25 weeks. Then mice in both groups were euthanized and the liver tissues were procured for the preparation of total RNAs, which were subjected to RNA-seq assay. While myeloid FoxO1 was upregulated in animal models and human subjects with NASH, the underlying mechanism is poorly understood. We found that myeloid cell conditional FoxO1-knockout mice were protected from developing NASH, culminating in the reduction of hepatic inflammation, steatosis and fibrosis. Mechanistically, FoxO1 counteracts Stat6 to skew macrophage polarization from M2 toward M1 signatures to perpetuate hepatic inflammation in NASH. FoxO1 appears as a pivotal mediator of macrophage activation in response to overnutrition and a therapeutic target for ameliorating hepatic inflammation to stem the disease progression from benign steatosis to NASH.
2022-05-24 | GSE203227 | GEO