Transcription profiling of human hypoxia exposed normal human esophageal epithelial cells
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ABSTRACT: To delineate the role of hypoxia in esophageal epithelial biology, we carried out gene array experiments using a non-transformed immortalized diploid human esophageal cell line, EPC2-hTERT (Mol Cancer Res. 2003;1:729-38). Unlike cancer cell lines, EPC2-hTERT has no genetic alterations at early passages that may affect the cellular response to hypoxia. Experiment Overall Design: EPC2-hTERT cells were exposed to moderate (1% O2) hypoxia in experiment 1 (Exp1) or severe (0.2% O2) hypoxia in experiment 2 (Exp2). Normoxia (21% O2) served as a control in both experiments.
Project description:Neonatal mouse cardiomyocytes (NMC) were cultured in normoxia (21% O2) or hypoxia (3% O2) with and without a lentiviral shRNA-mediated knockdown of Hif1-alpha. Total RNA was extracted from NMC using RNeasy kit, cDNA was synthesized using GeneChip WT cDNA Synthesis and Amplification kit (Affymetrix 900673) and hybridised to Affymetrix mouse high-resolution AltSplice microarrays.
Project description:Systemic arterial smooth muscle cells are exposed to a broad range of oxygen concentrations under physiological conditions. Hypoxia can modulate the proliferative response of smooth muscle cells leading to speculation about its role in vasculogenesis, vascular remodelling and the pathogenesis of arterial disease. The effect of hypoxia has been inconsistent, however, with both enhanced proliferation and growth arrest reported. Nevertheless, these reports support an important effect of hypoxia on smooth muscle cell proliferation and, given its physiological and clinical relevance, this requires clarification. We posited that variation in O2 concentration, within the range that exists in vivo, may have different effects on the proliferation and survival of vascular smooth muscle cells. Experiment Overall Design: Human aortic smooth muscle cells (HASMC) were propagated to passage 6 in SMGM-2 medium reached 80% confluence, the media was changed and the cells were incubated for a further 16 hrs or 48 hrs under either normoxic or hypoxic conditions (1% and 3%O2 ).
Project description:The aim of the experiment was to identify the genes up or downregulated by short term (12 hours) and long term (7 days) severe hypoxia (0.1% O2) in glioblastoma cells
Project description:Ischemia exists in many diseased tissues including arthritic joints, atherosclerotic plaques and malignant tumors. Macrophages accumulate in these sites and upregulate genes in response to the hypoxia present. We used microarrays to detail the hypoxia upregulated gene in human primary macrophages. Experiment Overall Design: Primary macrophages were differentiated for 7 days in vitro from human peripheral blood (monocyte-derived macrophages, MDMs) and were subjected to severe hypoxia (< 0.5% O2) or normoxia (20.9% O2) in 5% CO2 humidified multi-gas incubators.
Project description:Alternative RNA splicing analysis in Hep3B cell cultured under 21% (N1,3,5) or 1.2% (H2,4,6) oxygen Hypoxia is a common characteristic of many solid tumors. The hypoxic microenvironment stabilizes hypoxia-inducible transcription factor 1? (HIF1?) and 2? (HIF2?) to activate gene transcription, which promotes tumor cell survival. 95% of human genes are alternatively spliced, producing RNA isoforms that code functionally distinct proteins. Thus, effective hypoxia response requires increased HIF target gene transcription as well as proper RNA splicing of these HIF target genes. However, it is unclear if and how hypoxia regulates RNA splicing of HIF target genes. This study determined the effects of hypoxia on alternative splicing (AS) of HIF and non-HIF target genes in Hep3B cells and characterized the role of HIF in regulating AS of HIF induced genes. The results indicated that hypoxia generally promotes exon inclusion for hypoxia-induced, but reduces exon inclusion for hypoxia reduced genes. Mechanistically, HIF activity, but not hypoxia per se is found to be necessary and sufficient to increase exon inclusion of several HIF target genes including pyruvate dehydrogenase kinase 1 (PDK1). PDK1 splicing reporters confirmed that transcriptional activation by HIF is sufficient to increase exon inclusion of PDK1 splicing reporter. In contrast, transcriptional activation of the PDK1 minigene by other transcription factor in the absence of endogenous HIF target gene activation fails to alter PDK1 RNA splicing, demonstrating a novel role of HIF target gene(s) in regulating RNA splicing of HIF target genes. Implications:This study demonstrates a novel function of HIF in regulating RNA splicing of HIF target genes. We analyzed total RNA from Hep3B cells cultured under 21% (N1,3,5) or 1.2% (H2,4,6) oxygen using the Affymetrix Human Exon 1.0 ST platform. Array data was processed by Altanalyze software version 2.0.7. Techinical replicates were performed for Nx and Hx treated Hep3B cells
Project description:Hypoxia plays a key pathogenic role in the outcome of many pathologic conditions. To elucidate how organisms successfully adapt to hypoxia, a population of Drosophila melanogaster was generated, through an iterative selection process, that is able to complete its lifecycle at 4% O2, a level lethal to the starting parental population. Transcriptomic analysis of flies adapted for >200 generations was performed to identify pathways and processes that contribute to the adapted phenotype, comparing gene expression of three developmental stages with generation-matched control flies. A third group was included, hypoxia-adapted flies reverted to 21% O2 for five generations, to address the relative contributions of genetics and hypoxic environment to the gene expression differences. We identified the largest number of expression differences in 0.5-3 hr post-eclosion adult flies that were hypoxia-adapted and maintained in 4% O2, and found evidence that changes in Wnt signaling contribute to hypoxia tolerance in flies. A population of flies able to complete their life cycle at 4% O2 was selected from a starting population of 27 isogenic D. melanogaster lines exposed to increasingly lower O2 levels over many generations. Transcriptomic analysis of adapted flies maintained at 4% O2 or reverted to room air for five generations, and of generation matched naive controls, was performed to better understand changes in gene expression in adapted flies and to investigate the relative contributions of genetics versus environment to these differences.
Project description:Background: Constant hypoxia (CH) and intermittent hypoxia (IH) occur during several pathological conditions such as asthma and obstructive sleep apnea. Our research is focused on understanding the molecular mechanisms that lead to injury or adaptation to hypoxic stress using Drosophila as a model system. Our current genome-wide study is designed to investigate gene expression changes and identify protective mechanism(s) in D. melanogaster after exposure to severe (1% O2) intermittent or constant hypoxia. Methodology/Principal Findings: Our microarray analysis has identified multiple gene families that are up- or down-regulated in response to acute CH or IH. We observed distinct responses to IH and CH in gene expression that varied in the number of genes and type of gene families. We then studied the role of candidate genes (up-or down-regulated) in hypoxia tolerance (adult survival) for longer periods (CH-7 days, IH-10 days) under severe CH or IH. Heat shock proteins up-regulation (specifically Hsp23 and Hsp70) led to a significant increase in adult survival (as compared to controls) of P-element lines during CH. In contrast, during IH treatment the up-regulation of Mdr49 and l(2)08717 genes (P-element lines) provided survival advantage over controls. This suggests that the increased transcript levels following treatment with either paradigm play an important role in tolerance to severe hypoxia. Furthermore, by over-expressing Hsp70 in specific tissues, we found that up-regulation of Hsp70 in heart and brain play critical role in tolerance to CH in flies. Conclusions/Significance: We observed that the gene expression response to IH or CH is specific and paradigm-dependent. We have identified several genes Hsp23, Hsp70, CG1600, l(2)08717 and Mdr49 that play an important role in hypoxia tolerance whether it is in CH or IH. These data provide further clues about the mechanisms by which IH or CH lead to cell injury and morbidity or adaptation and survival. Expression profiles were determined by expression arrays in Drosophila melanogaster following acute constant or intermittent hypoxia. Three groups of samples were included in this analysis (3 x control, 3x CH treated and 3 x IH treated samples).
Project description:To determine the role of NOTCH3 in human esophageal epitheila homeostasis/squamous cell differentiation Zinc finger E-box binding (ZEB) proteins ZEB1 and ZEB2 are transcription factors essential in transforming growth factor (TGF)-β-mediated epithelial to mesenchymal transition (EMT), senescence and cancer stem cell maintenance through mutual negative regulation of the microRNA (miR)-200 family members. However, little is known as to how ZEB expressing tumor cells may emerge during invasive growth. We find that canonical Notch signaling prevents expansion of a unique subset of cells expressing ZEBs through NOTCH3 (N3). In primary esophageal squamous cell carcinoma (ESCC), ZEB1 is induced in tumor cells displaying EMT-like dedifferentiation at the invasive front of tumor nests with reciprocal downregulation of the miR-200. ZEB expression was associated with the lack of cellular capability of undergoing squamous differentiation through dysfunction of N3, implicated at the onset of normal esophageal squamous differentiation. Dominant-negative Mastermind-like1 (DNMAML1), a genetic pan-notch inhibitor, prevented CSL-dependent transcription, resulting in suppression of N3 expression and squamous differentiation while enriching EMT competent cells with robust upregulation of ZEBs and downregulation of the miR-200. Such a cell population demonstrated enhanced anchorage independent growth as well as tumor formation in nude mice. RNA interference (RNAi) experiments documented the requirement of ZEBs in TGF-β-mediated EMT. Invasive growth and impaired squamous differentiation was recapitulated upon Notch inhibition in organotypic 3D culture, a form of human tissue engineering. Finally, RNAi experiments revealed N3 as a key factor limiting the expansion of the ZEB expressing cells, providing novel mechanistic insights into the role of Notch signaling in ESCC cell fate regulation and disease progression. NOTCH3 was knockdown stably in immortalized human esophageal keratinocytes EPC2-hTERTstably by lentivirus-mediated gene transfer with shRNA directed against NOTCH3 (Open BiosystemsV2LHS_229748). A scrambled shRNA (Open Biosystems RHS4346) served as acontrol. Cells were stimulated with 0.6 mM calcium chloride to induce squamous cell differentiation for 72 hrs (0.09 mM Calcium Chloride as a unstimulated control) as described in Gastroenterology. 2010 Dec;139(6):2113-23 by Ohashi et al.
Project description:Purpose: The goal of this study is to identify the mRNA clusters that are regulated by EGFR under normoxia or hypoxia. Method: Total RNAs were extracted from HeLa cells expressing scrambled control or EGFR shRNA-E1 that cultured under normoxia or hypoxia (1% O2) for 24h. Customized Next-Generation RNA Deep Sequencing, including both small RNA application and whole transcriptome analysis, was performed according to the standard procedure instructed by Applied Biosystems. For whole transcriptome analysis, SOLiD fragment colorspace transcriptome reads (50nt) were mapped to the human genome (hg19) and assigned to ensemble transcripts using Bioscope 1.3.1 (Life Technologies). The values of reads per kilobase per million reads (RPKM) were determined by Bioscope 1.3.1 CountTags tool using default parameters. Primary alignments with a minimum mapping quality of 10 and minimum alignment score of 10 were counted. Results: Deep sequencing analysis identified subclasses of mRNAs that were affected by EGFR either under normoxia or hypoxia. EGFR-regulated mRNAs (with Log2 fold-change affected by EGFR M-bM-^IM-% 0.4 or M-bM-^IM-$ -0.4) were sorted and over-lapped with mRNAs that were targeted (based on published data and TargetScan prediction with total context score M-bM-^IM-$ -0.20) by the top miRNA candidates affected by EGFR under hypoxia, resulting in 439 mRNAs that regulated by EGFR and likely targeted by the miRNA candidates in response to hypoxia. Conclusion: Whole transcriptome analysis revealed a novel cluster of mRNAs that are likely regulated by EGFR through miRNAs in response to hypoxic stress. RNA profiles of HeLa cells expressing scrambled control (S) or EGFR shRNA-E1 (A1) that cultured under normoxia or hypoxia (1% O2) for 24h were generated by AB SOLiD curstomarized next-generation sequencing, including both small RNA application and whole transcriptome analysis. S: HeLa expressing scrambled control cultured under normoxia; A1: HeLa expressing EGFR shRNA-E1 cultured under normoxia; HS: HeLa expressing scrambled control cultured under hypoxia for 24h; HA1: HeLa expressing EGFR shRNA-E1 cultured under hypoxia for 24h. In total, 4 biological samples with no replicates resulted in 4 whole transcriptome RNA profiles.