A Novel Factor Associating with Hepatic Insulin Sensitivity in Humans with Nonalcoholic Fatty Liver Disease
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ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE134438 | GEO | 2019/07/18
REPOSITORIES: GEO
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Project description:Background and Aims: Insulin resistance is a key factor in the pathogenesis of NAFLD. We evaluated the importance of subcutaneous abdominal adipose tissue (SAAT) inflammation and both plasma and SAAT-derived exosomes in regulating insulin sensitivity in people with obesity and NAFLD. Methods: Adipose tissue inflammation (macrophage and T cell content and gene expression of proinflammatory cytokines), liver and whole-body insulin sensitivity (assessed by a hyperinsulinemic-euglycemic clamp and glucose tracer infusion), and 24-hour serial plasma cytokine concentrations were evaluated in three groups stratified by adiposity, insulin sensitivity and intrahepatic triglyceride (IHTG) content: 1) metabolically-healthy lean (LEAN; n=14); 2) metabolically-healthy obese with normal IHTG content (OB-NL; n=28); and 3) metabolically-unhealthy obese with NAFLD (OB-NAFLD; n=28). The effect of plasma and SAAT-derived exosomes on insulin action (insulin-stimulated Akt phosphorylation) in human skeletal muscle myotubes was assessed in a subset of participants. Results: Proinflammatory macrophages, proinflammatory CD4 and CD8 T cell populations, and gene expression of several cytokines in SAAT were greater in the OB-NAFLD than the OB-NL and LEAN groups. However, with the exception of PAI-1, which was greater in the OB-NAFLD than the LEAN and OB-NL groups, 24-hour plasma cytokine concentration areas-under-the-curve (AUC) were not different between groups. The percentage of proinflammatory macrophages and plasma PAI-1 concentration AUC were inversely correlated with both hepatic and whole-body insulin sensitivity. Compared with exosomes from OB-NL participants, plasma and SAAT-derived exosomes obtained from the OB-NAFLD group impaired insulin action in myotubes. Conclusion: These results suggest SAAT-derived exosomes and PAI-1 are involved in the pathogenesis of systemic insulin resistance in people with obesity and NAFLD. ClinicalTrials.gov number: NCT02706262.
2021-10-01 | GSE156906 | GEO
Project description:BACKGROUND. Dietary intake of saturated fat is a likely contributor to nonalcoholic fatty liver disease (NAFLD) and insulin resistance, but the mechanisms that initiate these abnormalities in humans remain unclear. We examined the effects of a single oral saturated fat load on insulin sensitivity, hepatic glucose metabolism, and lipid metabolism in humans. Similarly, initiating mechanisms were examined after an equivalent challenge in mice. METHODS. Fourteen lean, healthy individuals randomly received either palm oil (PO) or vehicle (VCL). Hepatic metabolism was analyzed using in vivo 13C/31P/1H and ex vivo 2H magnetic resonance spectroscopy before and during hyperinsulinemic-euglycemic clamps with isotope dilution. Mice underwent identical clamp procedures and hepatic transcriptome analyses. RESULTS. PO administration decreased whole-body, hepatic, and adipose tissue insulin sensitivity by 25%, 15%, and 34%, respectively. Hepatic triglyceride and ATP content rose by 35% and 16%, respectively. Hepatic gluconeogenesis increased by 70%, and net glycogenolysis declined by 20%. Mouse transcriptomics revealed that PO differentially regulates predicted upstream regulators and pathways, including LPS, members of the TLR and PPAR families, NF-κB, and TNF-related weak inducer of apoptosis (TWEAK). CONCLUSION. Saturated fat ingestion rapidly increases hepatic lipid storage, energy metabolism, and insulin resistance. This is accompanied by regulation of hepatic gene expression and signaling that may contribute to development of NAFLD.
2017-02-02 | GSE80259 | GEO
Project description:Among all the evaluated factors, only adipose tissue insulin sensitivity (assessed by clamped % suppression of serum free fatty acid), serum concentration of high molecular weight adiponectin, and plasma concentration of TCA cycle metabolites such as citric acid and cis-aconitic acid (assessed by metabolome analysis), associated significantly and positively with hepatic insulin sensitivity in NAFLD.
2016-12-23 | GSE92746 | GEO
Project description:Alteration of various metabolites has been linked to type 2 diabetes (T2D) and insulin resistance. However, identifying significant associations between metabolites and tissue-specific phenotypes requires a multi-omics approach. In a cohort of 42 subjects with different levels of glucose tolerance (normal, prediabetes and T2D) matched for age and body mass index, we calculated associations between parameters of whole-body positron emission tomography (PET)/magnetic resonance imaging (MRI) during hyperinsulinemic euglycemic clamp and non-targeted metabolomics profiling for subcutaneous adipose tissue (SAT) and plasma. Plasma metabolomics profiling revealed that hepatic fat content was positively associated with tyrosine, and negatively associated with lysoPC(P-16:0). Visceral adipose tissue (VAT) and SAT insulin sensitivity (K<sub>i</sub>), were positively associated with several lysophospholipids, while the opposite applied to branched-chain amino acids. The adipose tissue metabolomics revealed a positive association between non-esterified fatty acids and, VAT and liver K<sub>i</sub>. Bile acids and carnitines in adipose tissue were inversely associated with VAT K<sub>i</sub>. Furthermore, we detected several metabolites that were significantly higher in T2D than normal/prediabetes. In this study we present novel associations between several metabolites from SAT and plasma with the fat fraction, volume and insulin sensitivity of various tissues throughout the body, demonstrating the benefit of an integrative multi-omics approach.
2020-01-06 | MTBLS1051 | MetaboLights
Project description:A time course of the effect of overexpressing GPI-PLD on global gene expression in HepG2 cells was compared to control virus. Experiment Overall Design: This experiment compares the global gene expression in HepG2 cells that were either transduced with an adenovirus expressing GPI-phospholipase D or an adenovirus expressing beta galactosidase as a control. Treatment was for 6 or 12 hrs. Four replicates for each condition were used. 10 micrograms of total RNA was assayed per genechip using standard Affymetrix protocols. CONTEXT: Recent studies demonstrated that de novo lipogenesis is increased in patients with nonalcoholic fatty liver disease (NAFLD). Patients with NAFLD also have plasma lipid abnormalities. These lipid abnormalities may in part be related to insulin resistance, which is common in patients with NAFLD. Insulin resistance is associated with alterations in proteins involved in lipid metabolism including glycosylphosphatidylinositol-specific phospholipase D (GPI-PLD), which is involved in triglyceride metabolism. OBJECTIVE: The objective of the study was to determine whether alterations in serum and hepatic levels of GPI-PLD occur in patients with NAFLD. DESIGN AND PATIENTS: We examined the following: 1) levels of serum GPI-PLD in nondiabetics with nonalcoholic steatohepatitis, compared with matched controls; 2) hepatic expression of GPI-PLD mRNA in patients with normal liver or NAFLD; and 3) effect of overexpressing GPI-PLD vs. beta-galactosidase (control) on global gene expression in a human hepatoma cell line. RESULTS: The serum levels of GPI-PLD were significantly higher in patients with nonalcoholic steatohepatitis than in matched controls (119 +/- 24 vs.105 +/- 15 microg/ml, P = 0.047). The hepatic expression of GPI-PLD mRNA was increased nearly 3-fold in NAFLD patients, compared with patients with normal liver (3.1 +/- 2.6 vs. 1.1 +/- 1.0 arbitrary units per microgram total RNA, P = 0.026). Finally, overexpressing GPI-PLD was associated with an increase in de novo lipogenesis genes. CONCLUSIONS: Patients with NAFLD have elevated serum levels and hepatic expression of GPI-PLD, and its overexpression in vitro is associated with increased expression of de novo lipogenesis genes. These results suggest that GPI-PLD may play a role in the pathogenesis of NAFLD and/or its metabolic features and warrants further investigation.
2007-10-26 | E-GEOD-4731 | biostudies-arrayexpress
Project description:Vitamin D, in addition to calcium/phosphate metabolism and bone homeostasis regulation, has antiproliferative, anti-inflammatory and antifibrotic properties. These protective actions may have an impact in the progression of chronic liver disease including NAFLD (Non-alcoholic fatty liver disease). Vitamin D deficiency is associated with metabolic syndrome components, such as insulin resistance and dyslipidemia. NAFLD is often considered as the hepatic manifestation of metabolic syndrome, and a growing body of research suggests a relationship between vitamin D deficiency and NAFLD, with low levels of 25(OH)D associated with hepatic inflammation, and the severity and progression of NAFLD.
2022-04-14 | GSE200765 | GEO
Project description:Background & Aims: Although non-alcoholic fatty liver disease (NAFLD) is the most common liver disease worldwide, aspects of its molecular pathogenesis are unknown and clinical biomarkers for early diagnosis and accurate disease staging remain scarce. The aims of these experiments were to identify and characterize liver protein alterations in an animal model of NAFLD and explore the utility of novel candidate biomarkers in NAFLD patients. Methods: Liver protein fractions were analyzed in a relative quantitative proteomic approach utilizing isobaric tags for relative and absolute quantitation (iTRAQ) labeling combined with nano-liquid chromatography and tandem mass spectrometry (nLC-MS/MS). Differential expression was confirmed independently by western blotting and immunohistochemistry, first in mouse sections and then in biopsies from paediatric NAFLD patients. Candidate serum biomarkers were analyzed by enzyme-linked immunosorbent assay in serum from adult NAFLD patients. Results: Through proteomic profiling we identified decreased expression of hepatic glyoxalase 1 (GLO1) in an animal model of NAFLD. GLO1 protein levels were also found reduced in tissue biopsies from pediatric NAFLD patients. In vitro experiments demonstrated that, in response to lipid-loading in hepatocytes, GLO1 is first hyper-acetylated then ubiquitinylated and degraded, leading to an increase in reactive methylglyoxal. In a cohort of 62 biopsy-confirmed adult NAFLD patients serum levels of the primary methylglyoxal-derived advanced glycated endproduct, hydroimidazolone (MG-H1) were found strongly correlated with body mass index (r=0.619, p<0.0001). Conclusions: We characterize, for the first time, the post-translational modification and regulation of GLO1 expression in response to hepatic lipid loading with functional consequences in NAFLD patients.
2018-02-16 | PXD001442 | Pride
Project description:The transition from lean to obese states involves systemic metabolic remodeling that impacts insulin sensitivity, lipid partitioning, inflammation, and glycemic control. Here, we have taken a pharmacological approach to test the role of a nutrient-regulated chromatin modifier, lysine-specific demethylase (LSD1), in obesity-associated metabolic reprogramming. We show that systemic administration of an LSD1 inhibitor (GSK-LSD1) reduces food intake and body weight, ameliorates non-alcoholic fatty liver disease (NAFLD), and improves insulin sensitivity and glycemic control in mouse models of obesity. GSK-LSD1 has little effect on systemic metabolism of lean mice, suggesting LSD1 has a context-dependent role in promoting maladaptive changes in obesity. Analysis of insulin target tissues identified white adipose tissue as the major site of insulin sensitization by GSK-LSD1, where it reduces adipocyte inflammation and lipolysis. We demonstrate that GSK-LSD1 reverses NAFLD in a non-hepatocyte-autonomous manner, suggesting an indirect mechanism potentially via inhibition of adipocyte lipolysis and subsequent effects on lipid partitioning. Pair-feeding experiments further revealed that effects of GSK-LSD1 on hyperglycemia and NAFLD are not a consequence of reduced food intake and weight loss. These findings suggest that targeting LSD1 could be a strategy for treatment of obesity and its associated complications including type 2 diabetes and NAFLD.
2022-10-17 | GSE210761 | GEO
Project description:Patients with non-alcoholic fatty liver disease (NAFLD), especially advanced non-alcoholic steatohepatitis (NASH), have an increased risk of cardiovascular diseases (CVD) due to the production of pro-inflammatory factors, vasoactive and thrombogenic molecules, or insulin resistance and related disorders. While elevated risk and incidence of CVD events in NAFLD/NASH are well established, whether such events will, in turn, influence the pathogenesis of NAFLD remains unknown. Here, we show that myocardial infarction (MI) accelerates the linear hepatic pathological progression of NAFLD. In humans, NAFLD patients who experienced CVD events after their diagnosis of NAFLD show a rapid progression of hepatic fibrosis. In mouse models of NASH, MI promotes hepatic fibrosis, accompanied by elevated circulating Ly6Chi monocytes and their recruitment to the damaged liver tissues. Depleting these cells abrogate MI-induced hepatic pathological effects in mice with NASH. Meanwhile, MI substantially elevates circulating and cardiac periostin contents, which act on hepatocytes and stellate cells to promote hepatic lipid accumulation and fibrosis, finally exacerbating hepatic pathological progression of NASH. Additionally, specific silence of cardiac periostin markedly attenuates MI-induced hepatic pathological progression of mice with NASH. These preclinical and clinical results demonstrate that MI alternates systemic homeostasis and upregulates the production of pro-fibrotic factors, triggering cross-disease communication that accelerates hepatic pathological progression of NAFLD.
2024-06-04 | GSE254698 | GEO
Project description:Nuclear receptors (NRs) play a crucial role in non-alcoholic fatty liver disease (NAFLD) and have been widely studied(Tran et al. 2018). However, the underlying mechanisms of NR regulation remain largely unclear. Here, we show that miR-20b plays a key role in modulating PPARα, a master regulator of nutrient metabolism and energy homeostasis in the pathogenesis of fatty liver(Wahli et al. 1995; Dongiovanni and Valenti 2013). Using network analysis and RNA-seq to determine the correlation between NRs and microRNA in NAFLD patients, we revealed that miR-20b directly targets PPARα. The expression of miR-20b was remarkably upregulated in free fatty acid (FA)-treated hepatocytes and the livers of both obesity-induced mice and NAFLD patients. Overexpression of miR-20b dramatically increased hepatic lipid accumulation and plasma triglyceride levels. Furthermore, miR-20b significantly reduced fatty acid oxidation and mitochondrial biogenesis by directly targeting PPARα. Fenofibrate, a specific agonist of PPARα, lost its ability to ameliorate hepatic steatosis in miR-20b-introduced mice. Finally, inhibition of miR-20b dramatically increased FA oxidation and uptake, resulting in improved insulin sensitivity and a decrease in NAFLD progression. Taken together, these results demonstrate that the novel miR-20b directly targets PPARα, plays a significant role in hepatic lipid metabolism, and presents an opportunity for the development of novel therapeutics for NAFLD.
2021-03-09 | GSE168484 | GEO