Hepatic loss of Lis1 leads to fatty liver and predisposes to tumorigenesis in mice
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ABSTRACT:
PROVIDER: PRJNA422444 | ENA |
REPOSITORIES: ENA
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Project description:We found that genetic deletion of Lis1 (also known as Pafah1b1) in mouse liver led to increased lipid accumulation and inflammation in the liver. Further analysis revealed that loss of Lis1 led to endoplasmic reticulum (ER) stress and reduced triglyceride secretion. Attenuation of ER stress by tauroursodeoxycholic acid (TUDCA) diminished lipid accumulation in the Lis1 defecient hepatocytes. In addition, Golgi was disorganized in Lis1 deficient livers. These mutants exhibited increased hepatocyte ploidy and accelerated development of liver cancer when treated with DEN. Taken together, these findings suggest that Lis1 is involved in the development and progression of liver diseases from steatosis to liver cancer and provide a useful model for delineating the molecular pathways that lead to these diseases.
2018-02-15 | GSE108096 | GEO
Project description:Two long and one truncated isoforms (termed LAP*, LAP, and LIP, respectively) of the transcription factor CCAAT enhancer binding protein beta (C/EBPM-NM-2) are expressed from a single intronless Cebpb gene by alternative translation initiation. Isoform expression is sensitive to mammalian target of rapamycin (mTOR)-mediated activation of the translation initiation machinery and relayed through an upstream open reading frame (uORF) on the C/EBPM-NM-2 mRNA. The truncated C/EBPM-NM-2 LIP, initiated by high mTOR activity, has been implied in neoplasia, but it was never shown whether endogenous C/EBPM-NM-2 LIP may function as an oncogene. In this study, we examined spontaneous tumor formation in C/EBPM-NM-2 knockin mice that constitutively express only the C/EBPM-NM-2 LIP isoform from its own locus. Our data show that deregulated C/EBPM-NM-2 LIP predisposes to oncogenesis in many tissues. Gene expression profiling suggests that C/EBPM-NM-2 LIP supports a protumorigenic microenvironment, resistance to apoptosis, and alteration of cytokine/chemokine expression. The results imply that enhanced translation reinitiation of C/ EBPM-NM-2 LIP promotes tumorigenesis. Accordingly, pharmacological restriction of mTOR function might be a therapeutic option in tumorigenesis that involves enhanced expression of the truncated C/EBPM-NM-2 LIP isoform. A cohort of C/EBPb LIP heterozygous (+/L) and wild type (+/+) mice were kept over 25 months and animals showing palpable lymphoma were sacrificed. The lymphoma developed spontaneously. For each genotype, 5 lymphoma were used for RNA preparation and gene expression profiling analysis.
2014-12-16 | E-GEOD-53770 | biostudies-arrayexpress
Project description:Two long and one truncated isoforms (termed LAP*, LAP, and LIP, respectively) of the transcription factor CCAAT enhancer binding protein beta (C/EBPβ) are expressed from a single intronless Cebpb gene by alternative translation initiation. Isoform expression is sensitive to mammalian target of rapamycin (mTOR)-mediated activation of the translation initiation machinery and relayed through an upstream open reading frame (uORF) on the C/EBPβ mRNA. The truncated C/EBPβ LIP, initiated by high mTOR activity, has been implied in neoplasia, but it was never shown whether endogenous C/EBPβ LIP may function as an oncogene. In this study, we examined spontaneous tumor formation in C/EBPβ knockin mice that constitutively express only the C/EBPβ LIP isoform from its own locus. Our data show that deregulated C/EBPβ LIP predisposes to oncogenesis in many tissues. Gene expression profiling suggests that C/EBPβ LIP supports a protumorigenic microenvironment, resistance to apoptosis, and alteration of cytokine/chemokine expression. The results imply that enhanced translation reinitiation of C/ EBPβ LIP promotes tumorigenesis. Accordingly, pharmacological restriction of mTOR function might be a therapeutic option in tumorigenesis that involves enhanced expression of the truncated C/EBPβ LIP isoform.
2014-12-16 | GSE53770 | GEO
Project description:Loss of hepatic Mboat7 leads to liver fibrosis
| PRJNA587923 | ENA
Project description: Not available
| S-EPMC5892582 | biostudies-literature
Project description:Metabolic reprograming is one of the hallmarks of tumorigenesis. Using a combination of multi-omics, here we show that nuclear myosin 1 (NM1) serves a key regulator of cellular metabolism. As part of nutrient-sensing PI3K/Akt/mTOR pathway, NM1 forms a positive feedback loop with mTOR, and directly affects mitochondrial oxidative phosphorylation via transcriptional regulation of mitochondrial transcription factors TFAM and PGC1α. NM1 depletion leads to a suppression of PI3K/Akt/mTOR pathway, underdevelopment of mitochondria inner cristae and redistribution of mitochondria within a cell, which is associated with reduced expression of oxidative phosphorylation genes, decreased mitochondrial DNA copy number, and deregulated mitochondrial dynamics. This leads to a metabolic reprogramming of NM1 KO cells from oxidative phosphorylation to aerobic glycolysis and with that associated metabolomic profile typical for cancer cells, namely, increased amino acid-, fatty acid-, and sugar metabolism, and increase in glucose uptake, lactate production and intracellular acidity. We show that NM1 KO cells are able to form solid tumors in a nude mouse model even though they have supressed PI3K/Akt/mTOR signalling pathway suggesting that the metabolic switch towards aerobic glycolysis provide a sufficient signal for carcinogenesis. We suggest that NM1 plays a key role as tumor suppressor and that NM1 depletion may be partly responsible for the Warburg effect at the early onset of tumorigenesis.
2022-06-27 | GSE206858 | GEO
Project description: Not available
| S-EPMC3282066 | biostudies-literature
Project description:Objective: The rs641738C>T variant located near the membrane-bound O-acyltransferase domain containing 7 (MBOAT7) locus is associated with fibrosis in liver diseases, including non-alcoholic fatty liver disease (NAFLD), alcohol-related liver disease, hepatitis B and C. We aim to understand the mechanism by which the rs641738C>T variant contributes to pathogenesis of NAFLD. Design: Mice with hepatocyte-specific deletion of MBOAT7 (Mboat7 Δhep) were generated and livers were characterised by histology, flow cytometry, qPCR, RNA sequencing and lipidomics. We analysed the association of rs641738C>T genotype with liver inflammation and fibrosis in 846 NAFLD patients and obtained genotype-specific liver lipidomes from 280 human biopsies. Results: Allelic imbalance analysis of heterozygous human liver samples pointed to lower expression of the MBOAT7 transcript on the rs641738C>T haplotype. Mboat7 Δhep mice showed spontaneous steatosis characterised by increased hepatic cholesterol ester content after 10 weeks. After 6 weeks on a high fat, methionine-low, choline-deficient diet, mice developed increased hepatic fibrosis as measured by picrosirius staining (p<0.05), hydroxyproline content (p<0.05) and transcriptomics, while the inflammatory cell populations and inflammatory mediators were minimally affected. In a human biopsied NAFLD cohort, MBOAT7 rs641738C>T was associated with fibrosis (p=0.004) independent of the presence of histological inflammation. Liver lipidomes of Mboat7 Δhep mice and human rs641738TT carriers with fibrosis showed increased total lysophosphatidylinositol (LPI) levels. The altered LPI and phosphatidylinositol subspecies in MBOAT7 Δhep livers and humans rs641738TT carriers were similar. Conclusion: Mboat7 deficiency in mice and human points to an inflammation-independent pathway of liver fibrosis that may be mediated by lipid signalling and a potentially targetable treatment option in NAFLD.
2020-06-30 | GSE139992 | GEO
Project description: Not available
| S-EPMC8040158 | biostudies-literature
Project description:ARID1A, a DNA-binding component of the SWI/SNF ATP-dependent chromatin-remodeling complex, contributes to nucleosome repositioning and access by transcriptional regulators. Liver-specific deletion of Arid1a (Arid1a LKO) caused the development of age-dependent fatty liver disease in mice. Transcriptome analysis revealed upregulation of lipogenesis and down-regulation of fatty acid oxidation genes.
2019-01-10 | GSE124694 | GEO