Genome-wide mapping of HIF-2α binding under normoxia in human bronchial epithelial cells (BEAS-2B)
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ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE81635 | GEO | 2016/07/06
SECONDARY ACCESSION(S): PRJNA322171
REPOSITORIES: GEO
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Project description:Growing number of cancer (stem) cells and stem cells were described to accommodate constituent active HIF-2α under normoxia. Previous study of hypoxia effect may have obscured some of normoxic HIF-2α functions as hypoxia inducible features. Our interest in study of protective potential of HIFs in lung cells led us to discover pseudohypoxia functions of HIF-2α under normoxia in human bronchial epithelial cells which exhibit pluripotency related markers and features. Our study provided perspective to pseudohypoxia functions of HIF-2α via enrichment of de novo motifs. In addition to the C-TAD, the N-TAD of HIF-2α was found to contribute to targeting on these non-canonical loci. Further elucidation of pseudohypoxia mechanism could resolve its implication of malignancy or pluripotency. We report globally mapped binding of HIF-2α under normoxia by using high throughput sequencing
2016-07-06 | E-GEOD-81635 | biostudies-arrayexpress
Project description:Chronic hypoxia induces pulmonary vascular remodeling and pulmonary hypertension (PH). While it is established that transcription factors, hypoxia-inducible factors (HIF-1α/HIF-2α) activate gene programs that drive hypoxia-induced PH, the mechanism of HIF-1/2 activation is less clear. Here, we report that carboxylterminus of Hsp70-interacting protein (CHIP or Stub1) modulates HIF-1α and HIF-2α transcription rather than reducing their stability. Knocking-down Stub1 reduced hypoxic activation of HIF-1α mRNA, protein, and activity while enhancing hypoxic induction of HIF-2α mRNA, protein, and target genes in pulmonary vascular cells. Mechanistically, CBP/p300-mediated acetylation of lysine (K287) inactivates the ubiquitin ligase activity of Stub1 and triggers its translocation from the cytoplasm into the nucleus. There, it recognizes the HIF promoter and hypoxia response elements (HREs) in target genes. Expression of Stub1-K287Q mutant (mimicking acetylation) enhanced hypoxia-induced HIF-1α expression, while acetyl-deficient Stub1-K287R mutant had the opposite effect on HIF-α but enhanced hypoxia-induced HIF-2α transcriptional activity. Endothelial-Stub1 transgenic mice tolerated chronic hypoxia better, had less pulmonary vascular remodeling, reduced pulmonary vascular resistance, and greater cardioprotection. Thus, Stub1 nuclear translocation enhances hypoxic induction of HIF-1α activity while suppressing deleterious effects of HIF-2α. These observations indicate that nuclear-Stub1 synergizes with HIF-1α to promote transcriptional responses and antagonizes HIF2α-driven PH in chronic hypoxia.
2023-04-01 | GSE221264 | GEO
Project description:Inflammation is a significant risk factor for colon cancer. Recent work has demonstrated essential roles for several infiltrating immune populations in the metaplastic progression following inflammation. Hypoxia and stabilization of hypoxia-inducible factors (HIFs) are hallmark features of inflammation and solid tumors. Previously, we demonstrated an important role for tumor epithelial HIF-2α in colon tumors; however, the function of epithelial HIF-2α as a critical link in the progression of inflammation to cancer has not been elucidated. In colitis-associated colon cancer models, epithelial HIF-2α was essential in tumor growth. Concurrently, epithelial disruption of HIF-2α significantly decreased neutrophils in the colon tumor microenvironment. Intestinal epithelial HIF-2α-overexpressing mice demonstrated that neutrophil recruitment was a direct response to increased epithelial HIF-2α signaling. High-throughput RNA sequencing (RNA-seq) analysis of HIF-2α-overexpressing mice in conjunction with data mining from the Cancer Genome Atlas showed that the neutrophil chemokine CXCL1 gene was highly upregulated in colon tumor epithelium in a HIF-2α-dependent manner. Using selective peptide inhibitors of the CXCL1-CXCR2 signaling axis identified HIF-2α-dependent neutrophil recruitment as an essential mechanism to increase colon carcinogenesis. These studies demonstrate that HIF-2α is a novel regulator of neutrophil recruitment to colon tumors and that it is essential in shaping the protumorigenic inflammatory microenvironment in colon cancer.
2021-04-27 | GSE173363 | GEO
Project description:Mutational inactivation of VHL is the earliest genetic event in the majority of ccRCCs, leading to activation of the HIF-1α and HIF-2α transcription factors. While correlative studies of human ccRCCs and functional studies using human ccRCC cell lines have implicated HIF-1α as an inhibitor and HIF-2α as a promoter of aggressive tumour behaviours, their roles in tumour onset have not been functionally addressed. Using an autochthonous ccRCC model, we show genetically that Hif1a is necessary for tumour formation whereas Hif2a deletion has only minor effects on tumour initiation and growth. Both HIF-1α and HIF-2α are necessary for the clear cell phenotype. Transcriptomic and proteomic analyses revealed that HIF-1α regulates glycolysis while HIF-2α regulates genes associated with lipoprotein metabolism, ribosome biogenesis and E2F and MYC transcriptional activities. Deficiency of HIF-2α increased CD8+ T cell infiltration and activation. These studies reveal different functions of HIF-1α and HIF-2α in ccRCC. SIGNIFICANCE The roles of HIF-1α and HIF-2α in ccRCC pathogenesis remain unclear. Using a mouse genetic approach we show that HIF-1α but not HIF-2α is important for tumour formation, contrary to predictions from studies of human ccRCC. We show that HIF-1α and HIF-2α transcriptionally regulate different aspects of metabolism and identify HIF-2α as a suppressor of immune cell infiltration and activation.
2020-07-02 | PXD016630 | Pride
Project description:Hypoxia is a hallmark of renal ischemia reperfusion injury (IRI) and serves as an essential regulator of innate immune responses during this process, although the mechanisms of this regulation remain unclear. Here, we show that dendritic cell (DC)-specific genetic ablation of hypoxia-inducible factor (HIF) 2α, a transcription factor induced by oxygen shortage, leads to hyperactivation of natural killer T cells (NKTs), ultimately exacerbating renal IRI in mice. HIF-2α deficiency in DCs triggers IFN-γ and IL-4 production in NKTs, along with upregulation of type I interferon (IFN) and chemokine responses critical for NKT activation. Mechanistically, loss of HIF-2α in DCs promotes their expression of CD36, a scavenger receptor for lipid uptake, resulting in increased lipid accumulation. Furthermore, HIF-2α binds directly to a reverse hypoxia-responsive element (rHRE) in the CD36 promoter, supporting its transcriptional regulation of CD36. Importantly, CD36 blockade by sulfo-N-succinimidyl oleate (SSO), reduces NKT activation and abolishes the exacerbation of renal IRI in mice with DC-specific HIF-2α knockout. Taken together, our study reveals a previously unrecognized role of a HIF-2α-CD36 regulatory axis in rewiring DC lipid metabolism under IRI-associated hypoxia, and suggests a potential therapeutic target to resolve long-standing obstacles in clinical treatment of this severe complication.
2022-09-23 | GSE199875 | GEO
Project description:Gene expression profiling of primary mouse articular chondrocyte infected with recombinant adenovirus expressing the hypoxia inducible factor-2 alpha (HIF-2α) protein. In this study, we have attempted to explore the effects of HIF-2α overexpression on mouse transcriptome and have identified numerous genes which are involved in osteoarthritis pathogenesis.
2017-10-10 | GSE104794 | GEO
Project description:Chondrosarcomas, malignant cartilaginous neoplasms, are capable of transitioning to highly aggressive, metastatic, and treatment-refractory states, resulting in significant patient mortality. We aimed to uncover the transcriptional program directing such tumor progression in chondrosarcomas. Here, we conducted weighted correlation network analysis (WGCNA) to extract a characteristic gene module underlying chondrosarcoma malignancy. We identified hypoxia-inducible factor-2α (HIF-2α, encoded by EPAS1) as an upstream regulator that governs the malignancy gene module. HIF-2α was upregulated in high grade chondrosarcoma biopsies and HIF-2α gene amplification was associated with the poor prognosis of patients with chondrosarcoma. Using tumor xenograft mouse models, we demonstrated that HIF-2α confers chondrosarcomas the capacities required for tumor growth, local invasion, and metastasis. Pharmacological inhibition of HIF-2α in conjunction with the chemotherapy agents synergistically enhanced chondrosarcoma cell apoptosis and abolished malignant signatures of chondrosarcoma in mice. We expect that our insights into the pathogenesis of chondrosarcoma will provide guidelines for the development of novel molecular-targeted therapeutics for chondrosarcoma.
2020-08-21 | GSE156565 | GEO
Project description:To investigate the detailed molecular mechanisms for the regulatory role of HIF-2α in experimental colitis, microarray gene expression analysis was performed on colon RNA isolated from 6- to 8-week-old Hif-2αF/F, Hif-2αlΔIE mice treated with 3%DSS for 3 days. Background & Aims: Hypoxic inflammation is characterized by decreased oxygen tension in inflammatory foci, and is a notable feature in inflammatory bowel disease (IBD). Hypoxic response is mediated by transcription factors hypoxia-inducible factor (HIF)-1α and HIF-2α, both of which are highly induced in IBD. HIF-1α is a protective factor that limits intestinal barrier dysfunction during inflammation. However, the role of HIF-2α has not been assessed in hypoxic inflammation and IBD. Methods: A hypoxia reporter mouse model was used to test the presence of hypoxia and HIF-2α in dextran sulfate sodium (DSS) and Citrobacter rodentium (C.rod)-induced colitis. The role of HIF-2α in these mouse models of colitis was further assessed in mice with an intestinal epithelium-specific gain- and loss-of-function of HIF-2α. Results: Induction of hypoxia and HIF-2α was confirmed in both murine experimental colitis models and human IBD samples. Disruption of HIF-2α attenuated colonic inflammation whereas stabilization of HIF-2α potentiated inflammation in mouse models of colitis. Interestingly, intestine specific overexpression of HIF-2α but not HIF-1α leads to spontaneous colitis and premature death in mice. Further mechanistic analysis showed that HIF-2α is a driver for pro-inflammatory response and is critical regulator of intestinal epithelial-derived tumor necrosis factor (TNF)-α. Blocking TNF-α completely ameliorated HIF-2α potentiated intestinal inflammation. Conclusions: These data demonstrate that HIF-2α is a critical transcription factor essential in intestinal epithelium elicited inflammatory response. Global gene expression profiling in colon RNAs isolated from 7-week-old Hif-2αF/F (n=6, Shah 007) and Hif-2αΔIE (n=5, Shah 008).
2013-02-28 | E-GEOD-43416 | biostudies-arrayexpress
Project description:Transcriptomic analysis of nucleus pulposus (NP) tissues from intervertebral discs of 14- and 24-month-old mice with the conditional postnatal overexpression of HIF-2α. Hypoxia-inducible factors (HIFs) are essential for the homeostasis of the hypoxic tissues, and therefore, increased activity of the transcription factor HIF-2α is shown to contribute to the pathogenesis of mild disc degeneration in the spine. We examined the transcriptomic profiles of nucleus pulposus cells in control and K19-HIF-2α-dPA overexpression mice using microarrays.
2024-03-27 | GSE249908 | GEO
Project description:Bone is a highly dynamic tissue undergoing continuous formation and resorption. Here, we investigated differential but complementary roles of hypoxia-inducible factor (HIF)-1α and HIF-2α in regulating bone remodeling. Using RNA-seq analysis, we identified that specific genes involved in regulating osteoblast differentiation were similarly but slightly differently governed by HIF-1α and HIF-2α. We found that increased HIF-1α expression inhibited osteoblast differentiation via inhibiting RUNX2 function by upregulation of Twist2, confirmed using Hif1a conditional knockout (KO) mouse. Ectopic expression of HIF-1α via adenovirus transduction resulted in the increased expression and activity of RANKL, while knockdown of Hif1a expression via siRNA or osteoblast-specific depletion of Hif1a in conditional KO mice had no discernible effect on osteoblast-mediated osteoclast activation. The unexpected outcome was elucidated by the upregulation of HIF-2α upon Hif1a overexpression, providing evidence that Hif2a is a transcriptional target of HIF-1α in regulating RANKL expression, verified through an experiment of HIF-2α knockdown after HIF-1α overexpression. The above results were validated in an ovariectomized- and aging-induced osteoporosis model using Hif1a conditional KO mice. Our findings conclude that HIF-1α plays an important role in regulating bone homeostasis by controlling osteoblast differentiation, and in influencing osteoclast formation through the regulation of RANKL secretion via HIF-2α modulation.
2024-07-10 | GSE271730 | GEO