Microarray analysis among non-alcoholic fatty liver, non-alcoholic steatohepatitis, and type 2 diabetes mellitus rats
ABSTRACT: Non-alcoholic fatty liver (NAFL) has the potential to progress to non-alcoholic steatohepatitis (NASH) or to promote type 2 diabetes mellitus (T2DM). However, NASH and T2DM do not always develop coordinately. We established rat models of NAFL, NASH, and NAFL + T2DM to recapitulate different phenotypes associated with NAFLD and its progression. Microarrays were used to identify hepatic gene expression changes in each of these models. The goal is to identify a predictor of different NAFLD progressions. Non-alcoholic fatty liver disease (NAFLD) is recognized as a low-grade systemic inflammatory state with both hepatic and extra-hepatic manifestations. We aimed to identify common key regulators and adaptive pathways in different NAFLD phenotypes. NAFL, NASH and NAFL+T2DM rat models were used to represent simple fatty liver, fatty liver with severe hepatic manifestations, and fatty liver with severe metabolic manifestations, respectively. We applied microarray analysis to characterize the key regulators and adaptive pathways in different NAFLD phenotypes. There are 12 samples in our study which belonged to 4 groups, and each group contains 3 different samples.
Project description:Global gene expression patterns of 2 human steatosis and 9 human non-alcoholic steatohepatitis (NASH) together with their respective control patterns were analyzed to define the non-alcoholic fatty liver disease (NAFLD) progression molecular characteristics and to define NASH early markers from steatosis. Overall design: Human liver samples of steatosis and non-alcoholic steatohepatitis were selected for RNA extraction and hybridization on Affymetrix microarrays.
Project description:Non-alcoholic fatty liver disease (NAFLD) is characterized by a series of pathological changes that can progress from simple fatty liver disease to non-alcoholic steatohepatitis (NASH). The objective of this study is to describe changes in global gene expression associated with the progression of NAFLD. This study is focused on the expression levels of genes responsible for the absorption, distribution, metabolism and excretion (ADME) of drugs. Differential gene expression between three clinically defined pathological groups; normal, steatosis and NASH was analyzed. The samples were diagnosed as normal, steatotic, NASH with fatty liver (NASH fatty) and NASH without fatty liver (NASH NF). Genome-wide mRNA levels in samples of human liver tissue were assayed with Affymetrix GeneChip® Human 1.0ST arrays
Project description:In nonalcoholic fatty liver disease (NAFLD), hepatic gene expression and fatty acid (FA) composition have been reported independently but a comprehensive gene expression profiling in relation to FA composition is lacking. The aim was to assess this relationship. In a cross-sectional study, hepatic gene expression (Illumina Microarray) was first compared among 20 patients with simple steatosis (SS), 19 with nonalcoholic steatohepatitis (NASH), and 24 healthy controls (HC). FA composition in hepatic total lipids was compared between SS and NASH, and associations between gene expression and FA were examined. Gene expression differed mainly between HC and patients (SS and NASH), including genes related to unsaturated FA metabolism. Twenty-two genes were differentially expressed between NASH and SS; most of them correlated with disease severity and related more to cancer progression than to lipid metabolism. Biologically long-chain polyunsaturated FA (PUFA) (eicosapentaenoic acid + docosahexaenoic acid, arachidonic acid) in hepatic total lipids were lower in NASH than in SS. This may be related to overexpression of FADS1, FADS2, and PNPLA3. The degree and direction of correlations between PUFA and gene expression were different among SS and NASH which may suggest that low PUFA content in NASH modulates gene expression in a different way compared with SS or, alternatively, gene expression influences PUFA content differently depending on disease severity (SS versus NASH). Conclusion: Well-defined subjects with either healthy liver, SS or NASH showed distinct hepatic gene expression profiles including genes involved in unsaturated FA metabolism. In NASH, hepatic PUFA were lower and associations with gene expression were different than in SS. Overall design: Cross-sectional study, including patients with non-alcoholic fatty liver disease (25 SS, 23 NASH) and 24 healthy living liver donors as HC. Nine samples (5 SS, 4 NASH) were excluded during quality control. The final analysis inclulded 63 participants (20 SS, 19 NASH, 24 HC).
Project description:The mechanisms underlying the progression of non-alcoholic steatohepatitis (NASH) are not completely elucidated. In this study we have integrated gene expression profiling of liver biopsies of NASH patients with translational studies in a mouse model of steatohepatitis and with pharmacological interventions in isolated hepatocytes to identify a novel mechanism implicated in the pathogenesis of NASH. By using high-density oligonucleotide microarray analysis we identified a significant enrichment of known genes involved in the multi-step catalysis of long chain polyunsaturated fatty acids, including delta-5 and 6 desaturases. A combined inhibitor of delta-5 and delta-6 desaturases significantly reduced intracellular lipid accumulation and inflammatory gene expression in isolated hepatocytes. Gas chromatography analysis revealed impaired delta-5 desaturase activity toward the omega-3 pathway in livers from mice with high-fat diet (HFD)-induced NASH. Consistently, restoration of omega-3 index in transgenic fat-1 mice expressing an omega-3 desaturase, which allows the endogenous conversion of omega-6 into omega-3 fatty acids, produced a significant reduction in hepatic insulin resistance, hepatic steatosis, macrophage infiltration and necroinflammatory liver injury, accompanied by attenuated expression of genes involved in inflammation, fatty acid uptake and lipogenesis. These results were comparable to those obtained in a group of mice receiving a HFD supplemented with EPA/DHA. Of interest, hepatocytes from fat-1 mice or supplemented with EPA exhibited synergistic anti-steatotic and anti-inflammatory actions with the delta-5/ delta-6 inhibitor. Conclusion: These findings indicate that both endogenous and exogenous restoration of the hepatic balance between omega-6 and omega-3 fatty acids and/or modulation of desaturase activities exert preventive actions in NASH. The complete database comprised the expression measurements of 18185 genes for liver sample groups: 8 non-alcoholic steatohepatitis (NASH ) and 7 control samples.
Project description:Nonalcoholic fatty liver disease (NAFLD) is a common disorder characterized by excessive hepatic fat accumulation, and potentially resulting in non-alcoholic steatohepatitis (NASH), liver cirrhosis (LC) and end-stage liver disease We used Rat Genome 230 2.0 microarray to further highlight the rat liver tissues after high-fat emulsion feeding. Overall design: The rat model of nonalcoholic fatty liver disease (NAFLD) was established, and the expression profiles of liver tissues from NAFLD were detected at 2, 4, and 6 weeks using Rat Genome 230 2.0 array. Then the significantly changed genes related to NAFLD were identified. The relevance of gene expression profiles and biological processes was analyzed by bioinformatics and systems biology.
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:Non-alcoholic fatty liver disease (NAFLD) encompasses a spectrum of histological findings, from simple steatosis to steatohepatitis (NASH), the latter presenting a higher risk of cardiovascular and kidney diseases, type 2 diabetes and end-stage liver disease. NAFLD is seen as the hepatic manifestation of the metabolic syndrome and affects up to 70-80% of obese patients. There are currently no approved pharmacological therapies for NASH, thus the only option is lifestyle intervention or bariatric surgery in order to lose weight and to improve insulin resistance. Although surgical intervention has allowed collections of liver biopsies, transcriptomic data from livers are still scarce and especially follow-up data to evaluate the impact of weight loss intervention on the liver. Therefore we studied hepatic transcriptomic data in a large cohort of obese patients assessed for presence of NASH at baseline and 1 year follow-up. Patients visiting the obesity clinic of the Antwerp University Hospital for a problem of being overweight (BMI above 25 to 29.9 kg/m²) or obese (BMI above 30 kg/m²) were prospectively recruited and underwent a hepatic work-up. Patients were excluded from further analysis in case of significant alcohol consumption (>20 g/day), history of bariatric surgery, diagnosis of another liver disease, pre-existing diabetes. Patients who were, however, diagnosed with de novo diabetes at baseline or at follow-up were not excluded. If NAFLD was suspected, liver biopsy was proposed. For patients undergoing bariatric surgery (BS), a liver biopsy was proposed regardless of the criteria. Patients were reassessed after 1 year. Liver biopsy was performed percutaneously (16G Menghini) or peri-operatively (14G Tru-Cut). The different histological features of NAFLD were assessed using the NASH Clinical Research Network (NASH CRN) Scoring System. The presence of NASH was defined according to Chalasani et al. necessitating the combined presence of steatosis, ballooning and lobular inflammation. Overall design: Microarray data were obtained for 152 patients at baseline (44 no NASH, 104 NASH, 4 undefined) and 79 patients (54 no NASH, 22 NASH, 3 undefined) at 1 year follow-up (38 diet restriction [Diet], 41 bariatric surgery [BS]). When paired (baseline - follow-up) samples were available, the number in brackets in Sample name indicates the baseline number of the same patient.
Project description:Nonalcoholic fatty liver disease (NAFLD) has become the most common cause of liver disease affecting 20-30% of the population in developed countries. NAFLD is strongly associated with abdominal obesity and is recognized as the hepatic manifestation of the metabolic syndrome. In a subgroup of patients with NAFLD inflammation and fibrosis develops, this so-called Non-Alcoholic Steatohepatitis (NASH) may progress to cirrhosis and hepatocellular carcinoma. A multi-hit hypothesis has been proposed in which during the first “hit” fat accumulation occurs in hepatocytes from excessive delivery of fatty acids from adipose tissue, in addition there is an imbalance in lipid synthesis and export. However, the reason why fat accumulation is subsequently followed by inflammation and fibrosis in some patients is poorly understood. We studied the role of gene expression at the transcriptional level using microarray in bariatric patients from whom the liver histology was available. Patients scheduled for bariatric surgery were recruited in Pretoria/South-Africa. At the time of the procedure, tissue samples of the visceral and subcutaneous fat were taken for molecular analysis as well as liver tissue for histology, also full biochemical data was collected. Patients were grouped according histology: group I (<5% steatosis), group II (NAFLD, 30-50% steatosis) and group III (NASH). The 15 samples were used for microarray (nr patients respectively for stages I-II-III: 6-4-5).
Project description:FLORINASH - The role of intestinal microflora in non-alcoholic fatty liver disease (NAFLD) EU FP7-HEALTH, project number 241913<br>Florinash examined the role on the gut microbiota in NAFLD. Metagenomic, proteomic, metabolomic and transcriptomic data were integrated to give provide a systems biology approach to disease-associated studies. Liver biopsies were obtained from patients undergoing bariatric surgery; one was used to diagnose NAFLD, the other was used to examine the host transcriptome in NAFLD.
Project description:Non-alcoholic fatty liver disease (NAFLD) is the most common chronic liver disorder in industrialized countries. Liver samples from morbidly obese patients with all stages of NAFLD and controls were analysed by array-based DNA methylation and mRNA expression profiling. Bisulphite converted DNA from the 85 samples were hybridised to the Illumina Infinium 450k Human Methylation Beadchip