Whole transcriptome profiling of Japanese nonalcoholic fatty liver disease cohort.
Ontology highlight
ABSTRACT: Nonalcoholic steatohepatitis (NASH) is a severe form of nonalcoholic fatty liver disease (NAFLD) that is characterized by hepatic steatosis, inflammation, hepatocellular injury, and fibrosis, which lead to progressed cirrhosis and hepatocellular carcinoma. Despite its increasing prevalence on a global scale, the pathogenesis of NASH progression is not well understood. To elucidate the underlying mechanisms of NASH progression, we conducted transcriptome analyses of Japanese NAFLD cohort in our facility.
Project description:The pathological progression of nonalcoholic fatty liver disease (NAFLD) is driven by multiple factors, and nonalcoholic steatohepatitis (NASH) represents its progressive form. In our previous studies, we found that bicyclol had beneficial effects on NAFLD/NASH. Here we aim to investigate the underlying molecular mechanisms of the bicyclol effect on NAFLD/NASH induced by high-fat diet (HFD) feeding. A mice model of NAFLD/NASH induced by HFD-feeding for 8 weeks was used. As a pretreatment, bicyclol (200 mg/kg) was given to mice by oral gavage twice daily. Hematoxylin and eosin (H&E) stains were processed to evaluate hepatic steatosis, and hepatic fibrous hyperplasia was assessed by Masson staining. Biochemistry analyses were used to measure serum aminotransferase, serum lipids, and lipids in liver tissues. Proteomics and bioinformatics analyses were performed to identify the signaling pathways and target proteins. The real-time RT-PCR and Western blot analyses were performed to verify the proteomics data. As a result, bicyclol had a markedly protective effect against NAFLD/NASH by suppressing the increase of serum aminotransferase, hepatic lipid accumulation and alleviating histopathological changes in liver tissues. Proteomics analyses showed that bicyclol remarkably restored major pathways related to immunological responses and metabolic processes altered by HFD feeding. Consistent with our previous results, bicyclol significantly inhibited inflammation and oxidative stress pathway related indexes (SAA1, GSTM1 and RDH11). Furthermore, the beneficial effects of bicyclol were closely associated with the signaling pathways of bile acid metabolism (NPC1, SLCOLA4 and UGT1A1), cytochrome P450-mediated metabolism (CYP2C54, CYP2C70 and CYP3A25), biological processes such as metal ion metabolism (Ceruloplasmin and Metallothionein-1), angiogenesis (ALDH1A1) and immunological responses (IFI204 and IFIT3). These findings suggested that bicyclol is a potential preventive agent for NAFLD/NASH by targeting multiple mechanisms in future clinical investigations.
Project description:Non-alcoholic fatty liver disease (NAFLD) is the number one cause of chronic liver disease worldwide, with 25% of these patients developing nonalcoholic steatohepatitis (NASH). NASH significantly increases the risk of cirrhosis and decompensated liver failure. Past studies in rodent models have shown the knockout of glycine-N-methyltransferase (GNMT) results in rapid pro-gression of steatosis, fibrosis, and hepatocellular carcinoma. However, the attenuation of GNMT in subjects with NASH and the molecular basis for its impact on the disease process are still unclear. To address this knowledge gap, we show the reduction of GNMT protein levels in the liver of NASH subjects compared to healthy controls. To gain insight into the impact of decreased GNMT in the disease process, we performed global label-free proteome studies on the livers from a murine Western diet-based model of NASH. Histological and molecular characterization of the animal model demonstrate high resemblance to the human disease.
Project description:Nonalcoholic steatohepatitis (NASH), characterized by inflammation and fibrosis, is emerging as a leading etiology of hepatocellular carcinoma (HCC). However, the mechanisms underlying the pathogenesis of NASH are not well understood. Here, we show that membrane phospholipid (PL) composition determined by a remodeling process modulates the progression of NASH. The expression of lysophosphatidylcholine acyltransferase 3 (LPCAT3), a PL remodeling enzyme that produces polyunsaturated PLs, is dramatically suppressed in human NASH livers compared to controls. LPCAT3 expression is inversely correlated with NAFLD activity score and fibrosis stage. Loss of Lpcat3 in mouse liver promotes the development of both spontaneous and diet-induced NASH/HCC. Mechanistically, Lpcat3 deficiency increases reactive oxygen species production, likely due to impaired mitochondrial homeostasis as demonstrated by reduced mitochondrial DNA content and fragmented mitochondrial morphology. Overexpressing Lpcat3 in the liver ameliorates inflammation and fibrosis of NASH. These results suggest that manipulating LPCAT3 expression may be an effective therapeutic strategy for NASH.
Project description:Nonalcoholic steatohepatitis (NASH), characterized by inflammation and fibrosis, is emerging as a leading etiology of hepatocellular carcinoma (HCC). However, the mechanisms underlying the pathogenesis of NASH are not well understood. Here, we show that membrane phospholipid (PL) composition determined by a remodeling process modulates the progression of NASH. The expression of lysophosphatidylcholine acyltransferase 3 (LPCAT3), a PL remodeling enzyme that produces polyunsaturated PLs, is dramatically suppressed in human NASH livers compared to controls. LPCAT3 expression is inversely correlated with NAFLD activity score and fibrosis stage. Loss of Lpcat3 in mouse liver promotes the development of both spontaneous and diet-induced NASH/HCC. Mechanistically, Lpcat3 deficiency increases reactive oxygen species production, likely due to impaired mitochondrial homeostasis as demonstrated by reduced mitochondrial DNA content and fragmented mitochondrial morphology. Overexpressing Lpcat3 in the liver ameliorates inflammation and fibrosis of NASH. These results suggest that manipulating LPCAT3 expression may be an effective therapeutic strategy for NASH.
Project description:Background & Aims: Overnutrition is one of the major causes of non-alcoholic fatty liver disease (NAFLD) and its advanced form non-alcoholic steatohepatitis (NASH). Besides the quantity of consumed calories, distinct dietary components are increasingly recognized as important contributor to the pathogenesis of NASH. We aimed to develop and characterize a hitherto missing murine model which resembles both the pathology and nutritional situation of NASH-patients in Western societies. Methods: We developed a NASH-inducing diet (ND) enriched with sucrose, cholesterol and a high concentration of fats rich in saturated fatty acids in a composition which mimics Western food. C57Bl6/N mice were fed with the ND or control chow for 12 weeks. Biochemical, real-time polymerase chain reaction, Western Blot and immunohistochemical analyses were performed to characterize systemic and hepatic changes induced by ND-feeding. Immunohistochemistry was used to assess c-Jun levels and activation in 110 human NAFLD and control liver specimens applying tissue micro array technology. Results: ND-fed mice showed significant body weight gain, impaired glucose tolerance, elevated fasting blood glucose levels as well as decreased adiponectin and increased leptin serum levels compared to control mice. In the liver, ND-feeding led to marked steatosis, enhanced cholesterol levels, distinct signs of oxidative stress, hepatocellular damage, inflammation, activation of hepatic stellate cells, and beginning fibrosis. Transcriptome-wide hepatic gene expression analysis comparing ND-fed mice and control mice indicated main alterations in lipid metabolism and inflammatory processes. Search for over-represented transcription factor target sites among the differentially expressed genes identified AP-1 as the most likely factor to cause the transcriptional changes in ND-livers. Combining differentially expressed gene and protein-protein interaction network analysis identified c-Jun (a component of the AP-1 complex) as hub in the largest connected deregulated sub-network in ND-livers. In accordance, ND-livers revealed c-Jun-phosphorylation and nuclear translocation. Moreover, hepatic c-Jun RNA and protein expression was enhanced in ND-fed compared to control mice. Also NAFLD-patients showed enhanced hepatic c-Jun levels, which correlated with inflammation, and notably, with the degree of hepatic steatosis. Conclusions: The new dietary mouse-model shows important pathological changes also found in human NASH and indicates c-jun/AP-1 activation as critical regulator of hepatic alterations. Abundance of c-jun in NAFLD likely facilitates development and progression of NASH, and thus, c-jun appears as attractive prognostic and therapeutic target of NAFLD progression. 14-weeks old male C57BL/6N mice were fed with either regular diet or a newly designed NASH-inducing diet for 12 weeks. Hepatic gene expression levels were measured thereafter.
Project description:Nonalcoholic fatty liver disease (NAFLD), a progressive hepatic disease with ectopic fat accumulation, can evolve toward nonalcoholic steatohepatitis (NASH). To date, there is still no approved drug therapy, which remains a major unmet need. Previous study has indicated that tranilast ameliorates hepatic fibrosis and stellate cells activation in dietary rat model of NASH. However, the precise mechanism of tranilast in anti-NASH remains unclear.
Project description:Objective: Nonalcoholic fatty liver disease (NAFLD) is linked to obesity and diabetes, suggesting an important role of adipose tissue in the pathogenesis of NAFLD. Here we aim to investigate the interaction between adipose tissue and liver in NAFLD, and identify potential early plasma markers that predict NASH. Research Design and Methods: C57Bl/6 mice were chronically fed a high fat diet to induce NAFLD and compared with mice fed low fat diet. Extensive histological and phenotypical analyses coupled with a time-course study of plasma proteins using multiplex assay was performed. Results: Mice exhibited pronounced heterogeneity in liver histological scoring, leading to classification into 4 subgroups: LF-low (LFL) responders displaying normal liver morphology, LF-high (LFH) responders showing benign hepatic steatosis, HF-low (HFL) responders displaying pre-NASH with macrovesicular lipid droplets, and HF-high (HFH) responders exhibiting overt NASH characterized by ballooning of hepatocytes, presence of Mallory bodies, and activated inflammatory cells. Compared to HFL responders, HFH mice gained weight more rapidly and exhibited adipose tissue dysfunction characterized by decreased final fat mass, enhanced macrophage infiltration and inflammation, and adipose tissue remodelling. Plasma haptoglobin, IL-1β, TIMP-1, adiponectin and leptin were significantly changed in HFH mice. Multivariate analysis indicated that in addition to leptin, plasma CRP, haptoglobin, eotaxin and MIP-1α early in the intervention were positively associated with liver triglycerides. Intermediate prognostic markers of liver triglycerides included IL-18, IL-1β, MIP-1γ and MIP-2, whereas insulin, TIMP-1, GCP-2 and MPO emerged as late markers. Conclusions: Our data support the existence of a tight relationship between adipose tissue dysfunction and NASH pathogenesis and point to several novel potential predictive biomarkers for NASH. Keywords: Expression profiling by array Male wildtype C57Bl/6 mice were fed LFD or HFD for 21 weeks. Mice were divided into 4 groups based on liver histology.
Project description:Here, we found that microRNA-223 (miR-223) was highly elevated in hepatocytes after high fat diet (HFD) feeding in mice and in human nonalcoholic steatohepatitis (NASH) samples. Genetic deletion of the miR-223 induced a full spectrum of nonalcoholic fatty liver disease (NAFLD) in mice after long-term (up to one year) HFD feeding including NASH-related steatosis, inflammation, fibrosis and HCC. To better explore the mechanisms underlying the abnormalities observed in HFD-fed miR-223KO mice, we examined hepatic gene expression in 3-month-HFD-fed WT and miR-223KO mice by microarray analysis. Finally, we revealed that miR-223 plays a key role in controlling steatosis-to-NASH progression by inhibiting hepatic Cxcl10 and Taz expression.
Project description:The aim of this sudy is to investigate the prevalence of colorectal cancer (CRC) in patients with nonalcoholic fatty liver disease (NAFLD) and evaluate whether NAFLD is a risk factor for CRC.
Project description:Nonalcoholic fatty liver disease (NAFLD) associated with type 2 diabetes (T2D) easily progresses toward severe forms of nonalcoholic steatohepatitis (NASH) and fibrosis, and the underlying mechanism is under active investigation. Here, we established the role of transcription factor 7-like 2 (TCF7L2), the most significant T2D susceptibility gene, in NAFLD development and progression. Hepatic TCF7L2 expression was decreased in liver biopsies of patients with NAFLD. Based on the major risk factors for NAFLD development, liver-specific TCF7L2 knockout mice were subjected to a high-fat diet providing fatty acids (FAs) and refeeding/high-carbohydrate diet stimulating de novo lipogenesis. Hepatic TCF7L2 deficiency significantly increased the lipid synthetic pathways and hepatic TG accumulation by preferentially metabolizing carbohydrates than FAs. Mechanistically, TCF7L2 regulated miRNAs targeting SREBF1c and enhanced proteasome-mediated MLXIPL (ChREBP) degradation. Our findings will deepen the pathophysiological mechanism of NAFLD associated with dietary carbohydrate and diabetes, and will provide a potential target for treatment of NAFLD.