Adipocyte lipin 1 is positively associated with human metabolic health and regulates mouse systemic metabolism
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ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE239490 | GEO | 2024/07/15
REPOSITORIES: GEO
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Project description:Mutations in the gene encoding lipin 1 cause hepatic steatosis in fld mice, a genetic model of lipodystrophy. Lipin 1 appears to be highly involved in the control of fatty acid metabolism. Lipin 1 is most often located in the nucleus, but other studies suggest that lipin also has effects in the cytoplasm. However, the molecular function of lipin 1 is unclear. To evaluate the effects of activation of the lipin 1 system in liver, lipin 1beta was overexpressed in mouse liver using an adenoviral vector. We found that lipin 1 overexpression increased the expression of many genes involved in mitochondrial fatty acid oxidation while repressing expression of genes involved in lipogenesis. We believe that lipin is a transcriptional coactivator of the peroxisome proliferator-activated receptor (PPAR) complex. However, the many molecular aspects of its function remain unclear. Abstract of published manuscript follows:; Lipin 1 is an inducible amplifier of the hepatic PGC-1alpha/PPARalpha regulatory pathway.Finck BN, Gropler MC, Chen Z, Leone TC, Croce MA, Harris TE, Lawrence JC Jr, Kelly DP. Center for Cardiovascular Research and Washington University School of Medicine, St. Louis, Missouri 63110; Department of Medicine, Washington University School of Medicine, St. Louis, Missouri 63110. Perturbations in hepatic lipid homeostasis are linked to the development of obesity-related steatohepatitis. Mutations in the gene encoding lipin 1 cause hepatic steatosis in fld mice, a genetic model of lipodystrophy. However, the molecular function of lipin 1 is unclear. Herein, we demonstrate that the expression of lipin 1 is induced by peroxisome proliferator-activated receptor gamma (PPARgamma) coactivator 1alpha (PGC-1alpha), a transcriptional coactivator controlling several key hepatic metabolic pathways. Gain-of-function and loss-of-function strategies demonstrated that lipin selectively activates a subset of PGC-1alpha target pathways, including fatty acid oxidation and mitochondrial oxidative phosphorylation, while suppressing the lipogenic program and lowering circulating lipid levels. Lipin activates mitochondrial fatty acid oxidative metabolism by inducing expression of the nuclear receptor PPARalpha, a known PGC-1alpha target, and via direct physical interactions with PPARalpha and PGC-1alpha. These results identify lipin 1 as a selective physiological amplifier of the PGC-1alpha/PPARalpha-mediated control of hepatic lipid metabolism. Experiment Overall Design: Adult male C57BL6 mice were injected with adenovirus driving expression of mouse lipin 1beta or green fluorescent protein (GFP). Mice were recovered and sacrificed 6 days after injection. Total RNA was isolated and analyzed using Affymetrix microarray.
2008-06-13 | E-GEOD-5538 | biostudies-arrayexpress
Project description:Increased liver de novo lipogenesis (DNL) is a hallmark of nonalcoholic steatohepatitis (NASH). A key enzyme controlling DNL upregulated in NASH is ATP citrate lyase (ACLY). In mice, inhibition of ACLY reduces liver steatosis, ballooning and fibrosis and inhibits activation of hepatic stellate cells. Glucagon like peptide-1 receptor (GLP-1R) agonists lower body mass, insulin resistance and steatosis without improving fibrosis. Here, we find that combining an inhibitor of liver ACLY, bempedoic acid, and the GLP-1R agonist liraglutide reduces liver steatosis, hepatocellular ballooning, and hepatic fibrosis in a mouse model of NASH. Liver RNA analyses revealed additive downregulation of pathways that are predictive of NASH resolution, reductions in the expression of prognostically significant genes compared to clinical NASH samples, and a predicted gene signature profile that supports fibrosis resolution. These findings support further investigation of this combinatorial therapy to treat obesity, insulin resistance, hypercholesterolemia, steatohepatitis, and fibrosis in people with NASH.
2023-08-09 | GSE240409 | GEO
Project description:Increased liver de novo lipogenesis (DNL) is a hallmark of nonalcoholic steatohepatitis (NASH). A key enzyme controlling DNL upregulated in NASH is ATP citrate lyase (ACLY). In mice, inhibition of ACLY reduces liver steatosis, ballooning and fibrosis and inhibits activation of hepatic stellate cells. Glucagon like peptide-1 receptor (GLP-1R) agonists lower body mass, insulin resistance and steatosis without improving fibrosis. Here, we find that combining an inhibitor of liver ACLY, bempedoic acid, and the GLP-1R agonist liraglutide reduces liver steatosis, hepatocellular ballooning, and hepatic fibrosis in a mouse model of NASH. Liver RNA analyses revealed additive downregulation of pathways that are predictive of NASH resolution, reductions in the expression of prognostically significant genes compared to clinical NASH samples, and a predicted gene signature profile that supports fibrosis resolution. These findings support further investigation of this combinatorial therapy to treat obesity, insulin resistance, hypercholesterolemia, steatohepatitis, and fibrosis in people with NASH.
2023-08-09 | GSE240406 | GEO
Project description:Mutations in the gene encoding lipin 1 cause hepatic steatosis in fld mice, a genetic model of lipodystrophy. Lipin 1 appears to be highly involved in the control of fatty acid metabolism. Lipin 1 is most often located in the nucleus, but other studies suggest that lipin also has effects in the cytoplasm. However, the molecular function of lipin 1 is unclear. To evaluate the effects of activation of the lipin 1 system in liver, lipin 1beta was overexpressed in mouse liver using an adenoviral vector. We found that lipin 1 overexpression increased the expression of many genes involved in mitochondrial fatty acid oxidation while repressing expression of genes involved in lipogenesis. We believe that lipin is a transcriptional coactivator of the peroxisome proliferator-activated receptor (PPAR) complex. However, the many molecular aspects of its function remain unclear. Abstract of published manuscript follows: Lipin 1 is an inducible amplifier of the hepatic PGC-1alpha/PPARalpha regulatory pathway.Finck BN, Gropler MC, Chen Z, Leone TC, Croce MA, Harris TE, Lawrence JC Jr, Kelly DP. Center for Cardiovascular Research and Washington University School of Medicine, St. Louis, Missouri 63110; Department of Medicine, Washington University School of Medicine, St. Louis, Missouri 63110. Perturbations in hepatic lipid homeostasis are linked to the development of obesity-related steatohepatitis. Mutations in the gene encoding lipin 1 cause hepatic steatosis in fld mice, a genetic model of lipodystrophy. However, the molecular function of lipin 1 is unclear. Herein, we demonstrate that the expression of lipin 1 is induced by peroxisome proliferator-activated receptor gamma (PPARgamma) coactivator 1alpha (PGC-1alpha), a transcriptional coactivator controlling several key hepatic metabolic pathways. Gain-of-function and loss-of-function strategies demonstrated that lipin selectively activates a subset of PGC-1alpha target pathways, including fatty acid oxidation and mitochondrial oxidative phosphorylation, while suppressing the lipogenic program and lowering circulating lipid levels. Lipin activates mitochondrial fatty acid oxidative metabolism by inducing expression of the nuclear receptor PPARalpha, a known PGC-1alpha target, and via direct physical interactions with PPARalpha and PGC-1alpha. These results identify lipin 1 as a selective physiological amplifier of the PGC-1alpha/PPARalpha-mediated control of hepatic lipid metabolism. Keywords: response to lipin 1 activation
2006-08-16 | GSE5538 | GEO
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:Adipose tissue dysfunction signals progression of hepatic steatosis towards nonalcoholic steatohepatitis in C57Bl/6 mice
| PRJNA130277 | ENA
Project description:Hepatic lipogenesis is a central aspect of the feeding response and is aberrantly induced in the progression of fatty liver disease. Liver X receptors (LXRs) and sterol regulatory element-binding protein 1c (SREBP1c) are potent activators of the lipogenic gene program that promote triglyceride synthesis and hepatic steatosis in the insulin-resistant state. To date, key protein components of the LXR-SREBP1c axis have been uncovered that mediate transcriptional activation of SREBP1c by LXRs and nutrient and hormonal regulation. However, whether this regulatory pathway interfaces with long noncoding RNAs (lncRNAs) remains largely unexplored. Here we show that hepatic expression of Blnc1, a regulator of brown adipocyte development, is strongly associated with adiposity and liver fat content in mice. Blnc1 is required for the induction of SREBP1c and hepatic lipogenic genes in response to LXR activation. CRISPR/Cas9-mediated liver-specific inactivation of Blnc1 abrogates high fat diet-induced hepatic steatosis and insulin resistance. We further observed that liver Blnc1 expression is elevated in a mouse model of nonalcoholic steatohepatitis (NASH). Mice lacking Blnc1 in the liver are protected from diet-induced NASH and exhibit attenuated liver injury, inflammation and liver fibrosis. At the molecular level, proteomic analysis of the Blnc1 ribonucleoprotein complex in the liver identified endothelial differentiation related factor 1 (EDF1) as a component of the LXR transcriptional complex that acts in concert with Blnc1 to stimulate SREBP1c expression. These findings uncover a lncRNA ribonucleoprotein complex that licenses obesity-linked activation of hepatic lipogenesis and NAFLD pathogenesis.
2018-12-21 | GSE108609 | GEO
Project description:Non-alcoholic fatty liver disease (NAFLD) is characterized by excess lipid accumulation in hepatocytes and reprepresents a huge public health problem owing to its propensity to progress to non-alcoholic steatohepatitis (NASH), fibrosis, and liver failure. The lipids stored in hepatic steatosis are primarily triglycerides (TGs) synthesized by two acyl CoA:diacylglycerol acyltransferase (DGAT) enzymes. Either DGAT1 or DGAT2 catalyzes this reaction, and these enzymes have been suggested to differentially utilize exogenous or endogenously synthesized fatty acids, with DGAT2 being linked to storage of fatty acids from de novo lipogenesis, a process that is increased in NAFLD. However, whether DGAT2 is more responsible for lipid accumulation in NAFLD and the progression to fibrosis is currently unknown. Also, it is unresolved whether DGAT2 can be safely inhibited as a therapy for NAFLD. Here we induced NAFLD-like disease in mice by feeding a diet rich in fructose, saturated fat, and cholesterol and found that hepatocyte-specfici Dgat2 deficiency reduced expression of de novo lipogenesis genes and lowered liver TGs by ~70%. Importantly, the reduction of steatosis was not accompanied by increased inflammation or fibrosis, and insulin and glucose metabolism were unchanged. Conclusion: This study suggests that hepatic DGAT2 deficiency successfully reduced diet-induced hepatic steatosis and supports the development of DGAT2 inhibitors as a therapeutic strategy for treating NAFLD and preventing downstream consequences.
2020-05-26 | PXD013423 | Pride
Project description:The lipin phosphatidate phosphatase (PAP) enzymes (lipin 1, lipin 2, and lipin 3) catalyze a step in triglyceride and phospholipid biosynthesis, and genetic lipin deficiencies cause human disease that is triggered by metabolic stress, such as fasting. We assessed the protein interactome of lipins 1, 2, and 3 in hepatocytes, and identified unique protein associations between lipin 1 and U2 mRNA spliceosome components. Lpin1–/– mouse liver exhibited aberrant mRNA splicing in the fasted state, including mRNAs involved in mRNA processing and liver maturation. Aberrant splicing could be induced in cultured hepatocytes by lipin 1 knockdown or elevated phosphatidic acid levels, suggesting a role for lipin 1 PAP activity in splicing fidelity. Refeeding Lpin1–/– animals after fasting largely restored mRNA splicing fidelity. Reduced levels of ESRP2 splicing factor exclusively in the fasted state of Lpin1–/– liver was associated with widespread aberrant exon inclusion. These findings connect lipid homeostasis with mRNA splicing, and identify aberrant mRNA splicing in lipin 1 deficiency as a potential contributor to disease symptoms triggered by fasting.
2021-09-15 | GSE160984 | GEO
Project description:Liver is an important organ for fat metabolism. Excessive intake of a high-fat/energy diet is a major cause of hepatic steatosis and its complications such as nonalcoholic fatty liver disease and nonalcoholic steatohepatitis. Supplementation with lycopene, a natural compound, is effective in lowering triglyceride levels in the liver, although the underlying mechanism at the translational level is unclear. In this study, mice were fed a high-fat diet (HFD) to induce hepatic steatosis and treated with or without lycopene. Translation omics and transcriptome sequencing were performed on the liver to explore the regulatory mechanism of lycopene in liver steatosis induced by HFD, and identify differentially expressed genes (DEGs).
2021-06-17 | GSE178322 | GEO