Epigenetic silencing of the dual-role signal mediator, ANGPTL4 in tumor tissue and its overexpression in the urothelial carcinoma microenvironment
Ontology highlight
ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE102170 | GEO | 2017/10/01
SECONDARY ACCESSION(S): PRJNA396903
REPOSITORIES: GEO
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Project description:ANGPTL4 regulates plasma lipids, making it an attractive target for correcting dyslipidemia. However, ANGPTL4 inactivation in mice fed a high fat diet causes chylous ascites, an acute-phase response, and mesenteric lymphadenopathy. Here, we studied the role of ANGPTL4 in lipid uptake in macrophages and in the above-mentioned pathologies using Angptl4-hypomorphic and Angptl4-/- mice. Angptl4 expression in peritoneal and bone marrow-derived macrophages was highly induced by lipids. Recombinant ANGPTL4 decreased lipid uptake in macrophages, whereas deficiency of ANGPTL4 increased lipid uptake, upregulated lipid-induced genes, and increased respiration. ANGPTL4 deficiency did not alter LPL protein levels in macrophages. Angptl4-hypomorphic mice with partial expression of a truncated N-terminal ANGPTL4 exhibited reduced fasting plasma triglyceride, cholesterol, and non-esterified fatty acid levels, strongly resembling Angptl4-/- mice. However, during high fat feeding, Angptl4-hypomorphic mice showed markedly delayed and attenuated elevation in plasma serum amyloid A and much milder chylous ascites than Angptl4-/- mice, despite similar abundance of lipid-laden giant cells in mesenteric lymph nodes. In conclusion, ANGPTL4 deficiency increases lipid uptake and respiration in macrophages without affecting LPL protein levels. Compared with the absence of ANGPTL4, low levels of N-terminal ANGPTL4 mitigate the development of chylous ascites and an acute-phase response in mice.
2019-08-24 | GSE136240 | GEO
Project description:Characterization of ANGPTL4 function in macrophages and adipocytes using Angptl4-knockout and Angptl4-hypomorphic mice
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Project description:Protracted inflammatory responses are signatures common to many gastrointestinal disorders. Severe and chronic disorders often bring about extensive tissue damage, in turn leading to hypercytokinemia. Here, we show that stimuli like dextran sulphate sodium salt (DSS) and stearic acid (SA) cause acute colonic inflammation, and ANGPTL4 is an important regulator in mediating the extent of colonic inflammation. Using comparative microarray gene expression analysis, we seek to identify genes whose expression are altered during inflammation between ANGPTL4+/+ and ANGPTL4-/- mice.
2017-03-28 | GSE78500 | GEO
Project description:Angiopoietin-like 4 (ANGPTL4) is known to regulate various cellular and systemic functions. However, its cell-specific role in endothelial cells (ECs) function and metabolic homeostasis remains to be elucidated. Here, using endothelial-specific Angptl4 knock-out mice (Angptl4iEC), and transcriptomics and metabolic flux analysis, we demonstrate that ANGPTL4 is required for maintaining EC metabolic function vital for vascular permeability and angiogenesis. Knockdown of ANGPTL4 in ECs promotes lipase-mediated lipoprotein lipolysis, which results in increased fatty acid (FA) uptake and oxidation. This is also paralleled by a decrease in proper glucose utilization for angiogenic activation of ECs. Mice with endothelial-specific deletion of Angptl4 showed decreased pathological neovascularization with stable vessel structures characterized by increased pericyte coverage and reduced permeability. Together, our study denotes the role of endothelial-ANGPTL4 in regulating cellular metabolism and angiogenic functions of EC.
2023-11-22 | GSE211128 | GEO
Project description:Leptin protein was thought to be unique to leptin receptor (LepR), but the phenotypes of mice with mutation in LepR (db/db) and leptin (ob/ob) are not identical, and the cause remains unclear. Here, we show that db/db, but not ob/ob mice had defect in tenotomy-induced heterotopic ossification (HO), implicating alternative ligand(s) for LepR might be involved. Ligand screening revealed that ANGPTL4, a stress and fasting-induced factor, was elicited from brown adipose tissue after tenotomy, bound to LepR on PRRX1+ mesenchymal cells at the HO cite, thus promotes chondrogenesis and HO development. Disruption of LepR in PRRX1+ cells, or lineage ablation of LepR+ cells, or deletion of ANGPTL4 impeded chondrogenesis and HO in mice. Surprisingly, exogenous ANGPTL4 treatment not only promoted HO, but facilitated the transformation from white to brown adipose tissue in mice. These findings identify ANGPTL4 as a novel ligand for LepR to stimulate HO and regulate fat metabolism.
2024-07-03 | PXD043087 | Pride
Project description:Angiopoietin-like protein 4 (ANGPTL4, also referred to as Fiaf) has been proposed as circulating mediator between the gut microbiota and fat storage in adipose tissue. Very little is known about mechanisms of regulation of ANGPTL4 in the colon. Here we show that transcription and subsequent secretion of ANGPTL4 in human T84 and HT-29 colonocytes is highly induced by physiological concentrations of products of bacterial fermentation, the short chain fatty acids (SCFA). Induction of ANGPTL4 by SCFA cannot be mimicked by the histone deacetylase inhibitor Trichostatin A. SCFA induce ANGPTL4 by activating the nuclear receptor PPARγ, as shown by use of PPARγ antagonist, PPARγ knock-down, and transactivation assay, which shows activation of PPARγ but not PPARα and PPARδ. At concentrations required for PPARγ activation and ANGPTL4 induction in colonocytes, SCFA do not stimulate PPARγ in mouse 3T3-L1 and human SGBS adipocytes, suggesting that SCFA act as selective PPARγ modulators (SPPARM), which is supported by coactivator peptide recruitment assay and structural modelling. Consistent with the notion that fermentation leads to PPAR activation in vivo, feeding mice a diet rich in inulin was associated with induction of PPAR target genes and pathways in the colon, as shown by microarray and subsequent gene set enrichment analysis. It can be concluded that 1) SCFA potently stimulate ANGPTL4 synthesis in human colonocytes; 2) SCFA transactivate and bind to PPARγ by serving as selective PPAR modulators. Our data point to activation of PPARγ as a novel mechanism of gene regulation by SCFA in the colon.
2013-03-11 | GSE43065 | GEO
Project description:Renal cell carcinoma (RCC), the most common form of kidney cancer, is a heterogeneous disease with clear cell RCC (ccRCC) being the most prevalent and aggressive subtype. While most ccRCC tumors have elevated expression of angiopoietin-like 4 (ANGPTL4), in our study we identified a significant subset of patients whose cancers show no increase in ANGPTL4 expression. These patients have a worse prognosis compared to the patients with high expression of ANGPTL4. These ANGPTL4-low cancers are characterized by the increased frequency of wild-type Von Hippel-Lindau (wt VHL), a gene that is commonly mutated in ccRCC, and an enrichment for genes associated with lipid metabolism. Using RCC tumor models with wild type VHL, we demonstrate that ANGPTL4 behaves as a tumor suppressor. The loss of ANGPTL4 in ccRCC cell lines results in increased tumor growth and colony formation in a lysosomal acid lipase (LAL)-dependent manner, a phenotype rescued by the expression of N-terminus ANGPTL4. At the mechanistic level, the loss of ANGPTL4 increases lysosomal acid lipase activity in ccRCC cells. This data suggests that ANGPTL4 enacts its tumor-suppressive effects in ccRCC by regulating LAL activity. Importantly, the identified patient cohort with low ANGPTL4 expression may exhibit increased reliance on lipid metabolism, which can be a point of target for future therapy.
2024-07-30 | GSE273236 | GEO
Project description:Proteomics data for ANGPTL4/8 serum binding proteins study.
2023-01-20 | MSV000091103 | MassIVE
Project description:ANGPTL4 regulates plasma triglyceride levels by inhibiting lipoprotein lipase. Inactivation of ANGPTL4 decreases plasma triglycerides and reduces risk of coronary artery disease. Unfortunately, targeting ANGPTL4 for the therapeutic management of dyslipidemia and atherosclerosis is hampered by the observation that mice and monkeys in which ANGPTL4 is inactivated exhibit lipid accumulation in mesenteric lymph nodes. In mice these pathological events exclusively unfold upon feeding a high saturated fatty acid diet and are followed by an ultimately lethal pro-inflammatory response and chylous ascites. Here we show that Angptl4-/- mice fed a diet rich in trans fatty acids develop numerous lipid-filled giant cells in their mesenteric lymph nodes, yet do not have elevated serum amyloid and haptoglobin, do not exhibit ascites, and survive, unlike Angptl4-/- mice fed a saturated fatty acid-rich diet. In RAW264.7 macrophages the saturated fatty acid palmitate markedly increases markers of inflammation and the unfolded protein response, whereas the trans-unsaturated elaidate and the cis-unsaturated oleate have the opposite effect. In conclusion, trans and saturated fatty acids have very distinct biological effects. Furthermore, lipid accumulation in mesenteric lymph nodes is uncoupled from activation of an acute-phase response and chylous ascites, suggesting that ANGPTL4 should not be fully dismissed as target for dyslipidemia.
2017-04-27 | GSE98303 | GEO
Project description:Glucocorticoid plays an essential role in various stress responses and metabolism, which is mediated by the glucocorticoid receptor (GR) in cells. This hormonal action is integrated to transcriptional control of the GR target genes in cell type-specific and condition-dependent manners. In this study, we report that GR regulates the angiopoietin-like 4 (ANGPTL4) gene in a CCCTC-binding factor (CTCF)-mediated chromatin context in human hepatic HepG2 cells. There were at least four CTCF-enriched sites and two GR-binding sites in the ANGPTL4 locus. Among them, major CTCF-enriched site was positioned nearly GR-bound enhancer of this gene. Using treatment with the synthetic glucocorticoid dexamethasone (Dex), our data showed that CTCF is required for proper induction and subsequent silencing of ANGPTL4 gene. Interestingly, this gene induction was diminished under the long-term Dex pretreatment. Although ANGPTL4 locus maintains stable higher-order chromatin conformation at the basal and the Dex-treated states, liganded GR activated the ANGPTL4 gene, but not the neighboring three genes, via the interactions between enhancer, promoter and CTCF sites. These results reveal that liganded GR spatiotemporally controls ANGPTL4 gene in the chromosomal context.
2017-01-10 | GSE85343 | GEO