Browse
Submit Data
Databases
API
Help

Dataset Information

0 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Fumarate hydratase orchestrates hepatic steatosis via ULK1 mediated lipophagy

ABSTRACT: Hepatic lipid homeostasis is coordinated by various metabolic pathways, such as lipogenesis, lipid uptake, storage, and oxidation. However, the underlying mechanism that orchestrates metabolic crosstalk remains unclarified. Herein, we demonstrated that fumarate hydratase (FH) functioned as an indispensable adaptor governing mitochondria metabolism and lipid droplets (LDs) degradation. Hepatic FH overexpression prevented hepatic steatosis in normal mice and ob/ob mice without interfering mitochondrial lipid oxidation and lipogenesis. Strikingly, we found that FH selectively activated lipophagy-mediated LDs lipidolysis. Mechanistically, FH interacted with ULK1 and stabilized ULK1 through preventing its ubiquitination and degradation, resulting in lipophagy activation and the elimination of hepatic lipid accumulation. Meanwhile, hepatic ULK1 deficiency abrogated the protective effects in FH-overexpressing mice. Also, we clarified that the interaction between FH and ULK1 occurred in cytoplasm, but not in mitochondria. Cytoplasmic FH was sensitive to lipids and downregulated without affecting mitochondrial FH in vivo. Moreover, the FH-ULK1 axis was identified closely associated with hepatic steatosis in human patients. Taken together, our research demonstrates a “two-side” insight of FH on hepatic lipid metabolism and provides a promising strategy for fatty liver treatment.

ORGANISM(S): Mus musculus

PROVIDER: GSE256510 | GEO | 2024/02/26

REPOSITORIES: GEO

ACCESS DATA

Json Xml

Similar Datasets

Cardiomyocyte specific plin5 over expression

Project description:Presence of ectopic lipid droplets (LDs) in cardiac muscle is associated to lipotoxicity and tissue dysfunction. However, presence of LDs in heart is also observed in physiological conditions, such as at times when cellular energy needs and energy production from mitochondria fatty acid (FA) ?-oxidation are high (fasting). This suggests that development of tissue lipotoxicity and dysfunction is not simply due to the presence of LDs in cardiac muscle but due at least in part to alterations in LD function. To examine the function of cardiac LDs, we obtained transgenic mice with heart-specific plin5 over-expression (MHC-plin5), a member of the perilipin protein family. Hearts from MHC-plin5 mice expressed at least 4-fold higher levels of plin5 and exhibit a 3.5- fold increase in triglyceride content versus non-transgenic littermate. Chronic cardiac excess of LDs was found to result in mild heart dysfunction with decreased expression of PPAR? target genes, decreased mitochondria function and left ventricular concentric hypertrophia. Lack of more severe heart function complications may have been prevented by a strong increased expression of oxidative induced genes via NF-E2-related factor 2 anti-oxidative pathway. Perilipin 5 regulates the formation and stabilization of cardiac LDs, and promotes cardiac steatosis without major heart function impairment. Hearts from Four MCH-Plin5 mice and four control mice at the age of 12 weeks were harvested

2013-02-09 | E-GEOD-44192 | biostudies-arrayexpress

Liver-specific ceramide reduction alleviates steatosis and insulin resistance in alcohol-fed mice

Project description:Alcohol’s impairment of both hepatic lipid metabolism and insulin resistance (IR) are key drivers of alcoholic steatosis, the initial stage of alcoholic liver disease (ALD). Pharmacologic reduction of lipotoxic ceramide prevents alcoholic steatosis and glucose intolerance in mice, but potential off-target effects limit its strategic utility. Here, we employed a hepatic-specific acid-ceramidase (ASAH) overexpression model to reduce hepatic ceramides in a Lieber-DeCarli model of experimental alcoholic steatosis. We examined effects of alcohol on hepatic lipid metabolism, body composition, energy homeostasis and insulin sensitivity as measured by hyperinsulinemic-euglycemic clamp. Our results demonstrate that hepatic ceramide reduction ameliorates the effects of alcohol on hepatic lipid droplet accumulation by promoting VLDL secretion and lipophagy, the latter of which involves ceramide cross-talk between the lysosomal and lipid droplet compartments. We additionally demonstrate that hepatic ceramide reduction prevents alcohol’s inhibition of hepatic insulin signaling. These effects on the liver are associated with a reduction in oxidative stress markers and are relevant to humans, as we observe peri-lipid droplet ASAH expression in human ALD. Together, our results suggest a potential role for hepatic ceramide inhibition in preventing ALD.

2020-07-08 | GSE139015 | GEO

The Plant-derived Lipoxygenase Inhibitor Nordihydroguaiaretic Acid (NDGA) Attenuates Dyslipidemia and Hepatic Steatosis by Enhancing Fatty Acid Oxidation through Activation of PPAR-alpha

Project description:To test whether NDGA attenuate dyslipidemia and hepatic steatosis by enhancing fatty acid oxidation through activation of PPAR-α. Using wild type (WT, C57BL/6) fed with chow diet as control, WT mice were either fed with high-fat diet or high-fat diet with NDGA (2.5g/kg food); ob/ob mice were fed with either chow or chow with NDGA (2.5 g/kg food), and maintained on the respective diets for 16 weeks. The expression of lipid metabolism related genes in the liver of these mice were analyzed using Phalanx GPL6845 platform (Mouse OneArray V1). Together with other biochemical/physiological data, our results suggest that the beneficial actions of NDGA on dyslipidemia and hepatic steatosis in ob/ob mice are exerted primarily through enhanced fatty acid oxidation and energy utilization via the activation of PPAR- α receptor activity. To examine the changes in gene expression in liver of WT and ob/ob mice with different NDGA diet treatment, RNA isolated from 3 animals of each group were used for studies of gene expression profiles. Phalanx GPL6845 platform (Mouse OneArray V1) was used for the microarrays analysis.

2012-03-29 | E-GEOD-35075 | biostudies-arrayexpress

Changes in Hepatic Gene Expression upon Oral Administration of Taurine-Conjugated Ursodeoxycholic Acid in ob/ob Mice

Project description:We examined the effect of oral TUDCA treatment on hepatic steatosis and associated changes in hepatic gene expression in ob/ob mice. We administered TUDCA to ob/ob mice at a dose of 500 mg/kg twice a day by gastric gavage for 3 weeks. Body weight, glucose homeostasis, endoplasmic reticulum (ER) stress, and hepatic gene expression were examined in comparison with control ob/ob mice and normal littermate C57BL/6J mice.

2010-12-31 | E-GEOD-22608 | biostudies-arrayexpress

Changes in Hepatic Gene Expression upon Oral Administration of Taurine-Conjugated Ursodeoxycholic Acid in ob/ob Mice

Project description:We examined the effect of oral TUDCA treatment on hepatic steatosis and associated changes in hepatic gene expression in ob/ob mice.

2010-12-31 | GSE22608 | GEO

Liver lipophagy ameliorates nonalcoholic steatohepatitis through lysosomal lipid exocytosis

Project description:Nonalcoholic steatohepatitis (NASH) is a progressive disorder with aberrant lipid accumulation and subsequent inflammatory and profibrotic response. Lipid reduction through cytoplasmic lipolysis might adversely worsen steatohepatitis, however, the effect of autophagic lipolysis, lipophagy, remains obscure. We engineered the adaptor protein to induce lipophagy with lipid droplet targeting signal and modified LC3 interacting region. Activating hepatocyte lipophagy obviously mitigated both steatosis and NASH pathology. Mechanistically, lipophagy promoted the excretion of lipid from liver via lysosomal exocytosis and attenuated harmful accumulation of nonesterified fatty acid. This exocytosis was dependent on Ca2+ signal unlike the lysosomal dysfunction-related exocytosis. High content compound screening identified alpelisib and digoxin, clinically-approved compounds, as effective activators of lipophagy. Administration of alpelisib or digoxin inhibited the transition to steatohepatitis in mice fed high fat with low methionine low choline diet. Given all these data, activating lipophagy may be a promising therapeutic approach to prevent NASH progression.

2023-05-15 | GSE185911 | GEO

Transcriptional analysis of the expression and prognostic value of lipid droplet-localized proteins in hepatocellular carcinoma

Project description:The accumulation of lipid droplets (LDs) in hepatocytes is the main pathogenesis in nonalcoholic fatty liver disease (NAFLD), which is also the key risk factor for the progression of hepatocellular carcinoma (HCC). LDs behaviors are demonstrated to be associated with HCC advancement, and are tightly regulated by a subset protein localized on the surface of LDs. However, the role of LDs-localized protein in HCC has been rarely investigated. This study is focused on the transcriptional dynamic and prognostic value of LDs-localized protein in HCC. Firstly, we summarized the known LDs-localized proteins, which are demonstrated by immunofluorescence according to previous studies. Next, by the use of GEPIA/UALCAN/The Human Protein Atlas databases, we screened the transcriptional change in tumor and normal liver tissues, and found that 13 LDs-localized proteins may involve in the progression of HCC. Then we verified the transcriptional changes of 13 LDs-localized proteins by the use of HCC samples. Moreover, based on the assays of fatty liver of mice and human NAFLD liver samples, we found that the hepatic steatosis mainly contributed to the transcriptional change of selected LDs-localized proteins, indicating the involvement of these LDs-localized proteins in the negative role of NAFLD in HCC progression. Finally, we focused on the role of PLIN3 in HCC, and revealed that NAFLD status significantly promoted PLIN3 transcription in HCC tissue. Functional studies revealed that PLIN3 knockdown significantly limited the migration and chemosensitivity of hepatoma cells, suggesting the positive role of PLIN3 in HCC progression. Our study not only revealed the transcriptional change and prognostic value of lipid droplet-localized proteins in HCC, but also built the correlation between HCC and hepatic steatosis.

2023-04-16 | GSE223446 | GEO

Nordihydroguaiaretic Acid Improves Metabolic Dysregulation and Aberrant Hepatic Lipid Metabolism in Mice by Both PPAR-alpha-Dependent and -Independent Pathways

2012-03-30 | GSE35075 | GEO

RNA sequencing of liver tissues from liver-specific Usp39 knockout (Usp39-HKO) mice

Project description:Regulation of alternative splicing (AS) is crucial for gene expression and enables a single transcript to yield multiple isoforms that increase transcriptome and proteome diversity. Dysregulated AS has been linked to the development of non-alcoholic fatty liver diseases (NAFLD). However, the splicing factors involved in hepatic homeostasis and their functional mechanisms remain to be further characterized. Here, we report that spliceosome component Usp39 plays a critical role in the regulation of hepatocyte lipid homeostasis. We found that Usp39 expression is downregulated in hepatic tissues of NAFLD and non-alcoholic steatohepatitis (NASH) subjects. We observed increased lipid accumulation, spontaneous steatosis and impaired autophagy, lipophagy in particular, in mice with hepatocyte-specific Usp39 deletion. Combined analysis of RIP-seq and RNA-seq data revealed that Usp39 regulates AS of several autophagy-related genes including Hsf1. More specifically, deletion of Usp39 resulted in alternative 5’ splice site selection of exon 6 in Hsf1 and consequently reduced expression. Hsf1 was also found to be downregulated in NAFLD/NASH mice and patients. Importantly, overexpression of Hsf1 restored lipophagy, attenuated lipid accumulation and alleviated NASH caused by Usp39 deficiency. Taken together, our findings indicate that Usp39-mediated AS is crucial for sustaining lipophagy and lipid homeostasis in the liver.

2023-09-24 | GSE213633 | GEO