Hepatic DKK1 driven steatosis is CD36-dependent
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ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE197746 | GEO | 2022/11/19
REPOSITORIES: GEO
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Project description:Hepatic DKK1 driven steatosis is CD36-dependent
| PRJNA811955 | ENA
Project description:Dickkopf 1 (DKK1), which is expressed at high mRNA levels by fibroblasts in the dermis of human skin on the palms and soles, inhibits the function and proliferation of melanocytes in the epidermis of those areas via the suppression of beta-catenin and microphthalmia-associated transcriptor factor (MITF). In this study, we report that treatment of keratinocytes with DKK1 increases their proliferation and decreases their uptake of melanin, and that treatment of reconstructed skin with DKK1 induces a thicker and less pigmented epidermis. We investigated the effects of DKK1 on keratinocytes using DNA microarray technology. Keywords: compound treatment design
2007-12-31 | GSE9211 | GEO
Project description:Limb expression 1-like protein (LIX1L) plays important role in various liver disorders, but its role and underlying mechanism in nonalcoholic hepatitis (NASH) and HCC progression remains obscure. Here, we report that LIX1L functions as a key integrative regulator linking lipid metabolism and inflammation, adipose tissue dysfunction and hepatic microenvironment reprogramming which promotes NASH progression. LIX1L significantly upregulated in NAFLD/NASH patients, mouse models and palmitic acid-stimulated hepatocytes. Lix1l deletion inhibits lipid deposition, inflammatory response and fibrosis in liver as well as adipocyte differentiation by downregulation of fatty acid translocase CD36 expression, alleviating NASH and associated HCC progression. In contrast, adeno-associated virus (AAV)-mediated LIX1L overexpression exacerbates NASH progression in mice. Mechanistically, metabolic stress promotes PARP1 mediated poly-ADP-ribosylation (PARylation) of LIX1L, subsequently increasing the stability and RNA binding ability of LIX1L protein. LIX1L binds to AU-rich element (ARE) in the 3’ untranslated region (UTR) of CD36 mRNA, thus attenuating CD36 mRNA decay. In NASH and associated HCC mouse models, LIX1L deficiency-mediated downregulation of CD36 suppresses adipogenesis, hepatic lipid uptake, and reprograms the tumor-prone liver microenvironment with increased cytotoxic T lymphocytes (CTLs), reduced immunosuppressive cell proportions. These data indicate a systematic function of LIX1L in the pathogenesis of NASH and underscore the PARP1/LIX1L/CD36 axis as a potential target for treatment of NASH and associated HCC.
2024-04-25 | GSE264479 | GEO
Project description:Objective：Phospholipase D1 (PLD1), a phosphatidylcholine-hydrolyzing enzyme, has been found to be involved in cellular lipid metabolism. However, how PLD1 involves in hepatocyte lipid metabolism and thus affects non-alcoholic fatty liver diseases (NAFLD) has not been explicitly explored. Method: NAFLD is induced in hepatocyte-specific Pld1 knockout (Pld1(H)-KO) mice or control (Pld1-Flox) mice with a high fat diet (HFD) for 20 weeks. Plasma glucose and lipid levels, liver lipid and function parameters and inflammation- and fibrogenesis-related gene expression levels were studied. Changes in lipid composition of liver were detected by lipidomic analyses. Changes in gene expression profile were detected by mRNA sequencing. In vitro, alpha mouse liver 12 (AML12) cells were incubated with sodium palmitate (SP) to explore the mechanisms of PLD1 on development of NAFLD. The protein levels of PLD1 and CD36 were detected in the liver tissues of NAFLD patients. Finally, the therapeutic effect of NAFLD by inhibiting PLD with 5-Fluoro-2-indolyl deschlorohalopemide (FIPI) was examined. Results: PLD1 expression levels were increased in the liver tissues of NAFLD patients and the hepatocytes of HFD-induced mice. Compared with Pld1-Flox mice, Pld1(H)-KO mice exhibited lower plasma glucose and lipids levels, and decreased lipid accumulation, inflammation and fibrosis related gene expression levels in the liver tissues after HFD feeding. Inhibition of hepatocyte PLD1 significantly altered lipid composition, especially phosphatidic acids (PA) and lyso-PAs (LPA) levels in the liver tissues after NAFLD. Transcriptomic analysis showed that hepatocyte specific deficiency of PLD1 mainly decreased CD36 expression levels in the NAFLD liver tissues, which was confirmed at the protein and gene expression levels. In vitro, inhibition of PLD1 markedly decreased CD36 expression and lipid accumulation in SP treated AML12 cells. Furthermore, PA, the downstream product catalyzed by PLD1, increased the expression levels of CD36 and lipid accumulation in vitro, which was reversed by PPARγ antagonist. These suggested that PPARγ played an important role in transcriptional regulation of CD36 expression after PA stimulation. Finally, PLD inhibitor FIPI had significant therapeutic effect on HFD-induced NAFLD. Conclusion: Hepatocyte-specific deficiency of PLD1 ameliorates lipid accumulation and NAFLD development by inhibiting PPARγ/CD36 pathway conducted by PA.
2023-08-01 | GSE207281 | 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
Project description:Nonalcoholic fatty liver disease (NAFLD) is strongly associated with insulin resistance (IR), but little is known about the key genetic driver that links these two disorders. We aimed to elucidate the mechanism by which Smoothened (Smo), a G-protein coupled receptor, contributes to pathogenesis of NAFLD and IR.
2023-03-01 | GSE213621 | GEO
Project description:Nonalcoholic fatty liver disease (NAFLD) is strongly associated with insulin resistance (IR), but little is known about the key genetic driver that links these two disorders. We aimed to elucidate the mechanism by which Smoothened (Smo), a G-protein coupled receptor, contributes to pathogenesis of NAFLD and IR.
2023-03-01 | GSE213183 | GEO
Project description:Non-alcoholic fatty liver disease (NAFLD) is becoming increasingly common and is a leading cause of end stage liver diseases such as cirrhosis and hepatocellular carcinoma. The rise in NAFLD closely parallels the global epidemic of obesity and type 2 diabetes mellitus (T2DM), and there is a clear interrelationship between abnormal lipid metabolism, insulin resistance, and NAFLD progression. Several genetic loci have been identified as contributors to NAFLD progression, all of which are consistently linked to abnormal lipid metabolic processes in the liver. The common loss-of-function variant rs641738 (C>T) near the gene encoding Membrane_x0002_Bound O-Acyltransferase 7 (MBOAT7) is associated with increased susceptibility to NAFLD as well as the entire spectrum of NAFLD progression. The MBOAT7 gene encodes a lipid metabolic enzyme that is capable of esterifying polyunsaturated fatty acyl-CoAs to LPI substrates to generate phosphatidylinositol (PI) lipids. We previously showed that antisense oligonucleotide (ASO)-mediated knockdown of Mboat7 in mice promoted high fat diet-induced hepatic steatosis, hyperinsulinemia, and systemic insulin resistance (Helsley et al., 2019). Thereafter, other groups showed that hepatocyte-specific genetic deletion of Mboat7 promoted striking fatty liver and NAFLD progression but does not alter insulin sensitivity, suggesting the potential for cell autonomous roles. Here, we show that MBOAT7 function in adipocytes contributes to diet- 3 induced metabolic disturbances including hyperinsulinemia and systemic insulin resistance. The expression of Mboat7 in white adipose tissue closely correlates with diet-induced obesity across a panel of ~100 inbred strains of mice fed a high fat/high sucrose diet. Moreover, adipocyte_x0002_specific genetic deletion of Mboat7 is sufficient to promote hyperinsulinemia, systemic insulin resistance, and mild fatty liver. Unlike in the liver, where Mboat7 plays a relatively minor role in maintaining arachidonic acid (AA)-containing PI pools, Mboat7 is the major source of AA_x0002_containing PI pools in adipose tissue. Our data demonstrate that MBOAT7 is a critical regulator of adipose tissue PI homeostasis, and adipocyte MBOAT7-driven PI biosynthesis is closely linked to hyperinsulinemia and insulin resistance in mice.
2023-04-04 | GSE203414 | GEO
Project description:Super Enhancers are a class of DNA Cis-regulatory elements that can regulate cell identity, cell fate, stem cell pluripotency, and even tumorigenesis.Increasing evidence shows that epigenetic modifications play an important role in the pathogenesis of various types of cancer. However, current research is far from sufficient to reveal the complex mechanisms behind epigenetic modifications.The aim of this study is to explore the function and mechanism of a new Super Enhancer in Pancreatic ductal adenocarcinoma (PDAC) tumors. By using epigenetic modification and chromatin interaction information, we found a new Super Enhancer enriched with abnormal active histone modifications in PDAC tumors and cells, called DKK1-super-enhancer (DKK1-SE).DKK1-SE was grouped according to the activity modification information, and the e1 component was identified as the main active unit by dual luciferase reporter gene system and dCas9-KRAB system.DNA motif analysis and core site deletion assay revealed that the e1 component possessed AP1 transcription factor family binding sites.Mechanically, AP1 activates DKK1 transcriptional activity by recruiting JUND and FOSL2 to induce enhancer chromatin remodeling.CRISPR/ Cas9-mediated deletion of DKK1-SE resulted in significant downregulation of its target gene DKK1.Analysis of TCGA data of PDAC tumors combined with immunohistochemical results of PDAC patients demonstrated that DKK1 was closely related to malignant clinical features of PDAC.Bioinformatics analysis of RNA-seq data showed that DKK1 was mainly related to tumor-related biological functions such as extracellular matrix, cell adhesion, angiogenesis, and cell proliferation.Cell malignant phenotype assay showed that deletion or interference of DKK1-SE significantly inhibited the proliferation, colony formation, migration and invasion of PANC-1, and these phenomena were partially alleviated after restoring DKK1 expression in DKK1-SE deficient cells.Experiments of Subcutaneous transplantation tumor in nude mice and Orthotopic transplantation tumor model showed that DKK1-SE deletion not only inhibited tumor proliferation, but also reduced the complexity of tumor microenvironment, resulting in less angiogenesis of tumor tissues and reduced fibrosis degree.In conclusion, DKK1-SE drives the expression of DKK1 by recruiting AP1 family transcription factors, which plays a carcinogenic role in PDAC tumors and enhances the complexity of the tumor microenvironment.
2023-12-12 | GSE248887 | GEO
Project description:Non-alcoholic fatty liver disease (NAFLD) is a major problem in obese peoples and caused by unbalanced uptake of fatty acid. Novel drug identification is necessary to develop effective therapies. We combine LOPAC® and High-Content system to identify compounds significantly reducing intracellular lipid droplets after high fat medium (HFM) treatment. Among 1280 compounds, 5 show efficacy in lipid droplet reduction. To construct the underlying regulatory network, whole-genome transcriptomic, pathway, and connectivity map analysis are performed.
2018-01-31 | GSE109836 | GEO