Transcriptional profile assessed by microarrays of the tidepool sculpin and silverspotted sculpin exposed to hypoxia over time
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ABSTRACT: Transcriptional responses to hypoxia were compared between a hypoxia tolerant fish (tidepool sculpin; Oligocottus maculosus) and a hypoxia intolerant fish (silverspotted sculpin; Blepsias cirrhosus). To determine if, and how, transcriptional plasticity is associated with differences in hypoxia tolerance, each species was subjected to a hypoxic time-course and liver was sampled at normoxia, 3hr, 8hr, 24hr, 48hr and 72hr of hypoxia. The hypoxic level for each species was scaled to the species' own tolerance level (relative exposure) in order to elicit similar tissue level hypoxia between the two sculpin species. Each species was also subjected to a single environmental O2 tension (absolute exposure) and sampled at 24 hrs of hypoxia.
Project description:Transcriptional responses to hypoxia were assessed in three species of marine fish (smoothhead sculpin [Artedius lateralis], sailfin sculpin [Nautichthys oculafasciatus] and Pacific staghorn sculpin [Leptocottus armatus]) all of which have previously been shown to share the same level of hypoxia tolerance. To determine if there is convergence in mechanisms underlying phenotypic convergence of hypoxia tolerance, each species was exposed to short-term (8 hours) and long-term (72 hours) hypoxia. Specifically, liver was sampled and mRNA was extracted from each species at normoxia, 3hr, 8hr, 24hr, 48hr and 72hr of hypoxia.
Project description:We hypothesize that the culture media collected from macrophages exposed to intermittent hypoxia will induce a greater pro-inflammatory gene profile in naïve cultured macrophages than will culture media collected from macrophages exposed to sustained hypoxia. We will evaluate gene expression using microarray analysis of RNA collected from RAW 264.7 macrophages cultured for 24 hours in DMEM media obtained from 1) cells cultured with intermittent hypoxia (2 minute cycles: 90 seconds at 40 Torr and 30 seconds at 8 Torr), 2) media exposed to intermittent hypoxia, 3) cells cultured with sustained hypoxia (8 Torr), 4) media exposed to sustained hypoxia and 4) standard tissue culture conditions (fresh DMEM media; reference).
Project description:We hypothesize that cultured macrophages directly exposed intermittent hypoxia will have a greater change in expression in genes related to inflammatory response than macrophages exposed to sustained hypoxia. We will evaluate gene expression using microarray analysis of RNA collected from RAW 264.7 macrophages cultured under the following environmental conditions: 1) 4 hours of intermittent hypoxia (2 minute cycles: 90 seconds at 40 Torr and 30 seconds at 8 Torr), 2) 4 hours of sustained hypoxia (8 Torr), and 3 ) standard tissue culture conditions (141 Torr; reference).
Project description:In order to understand the chronic hypoxia (CH) effect upon the absence of dystrophin, Drosophila melanogaster wild type and the model for DMD (dmDys), in which all dystrophins expression was knocked out by iRNA, were exposed to high altitude hypoxia (hypobaric hypoxia) during a 16-day climbing period reaching the summit of Mount McKinley (6194 meters above sea level). Furthermore, dmDys and Drosophila wild type were exposed to normobaric hypoxia (hypoxic chamber) following the same oxygen levels observed during the climbing expedition and to normoxic conditions for comparison. Affymetrix GeneChip® profiling was performed for individual flies from each experimental group. CH-dmDys differentially expressed 1281 genes, whereas control group differentially expressed 57 genes. Eight heat shock protein genes detected in the CH-dmDys microarray study were down-regulated, instead of up-regulated as seen in wild type hypoxic flies. This result suggests a differential gene expression response to CH, which could affect muscle performance.These results suggest that dmDys is more sensitive to CH due to reduced muscle function and hypoxic stress response. In order to understand the chronic hypoxia (CH) effect upon the absence of dystrophin, Drosophila melanogaster wild type and the model for DMD (dmDys), in which all dystrophins expression was knocked out by iRNA, were exposed to high altitude hypoxia (hypobaric hypoxia) during a 16-day climbing period reaching the summit of Mount McKinley (6194 meters above sea level). Furthermore, dmDys and Drosophila wild type were exposed to normobaric hypoxia (hypoxic chamber) following the same oxygen levels observed during the climbing expedition and to normoxic conditions for comparison. Affymetrix GeneChip® profiling was performed for individual flies from each experimental group. CH-dmDys differentially expressed 1281 genes, whereas control group differentially expressed 57 genes. Eight heat shock protein genes detected in the CH-dmDys microarray study were down-regulated, instead of up-regulated as seen in wild type hypoxic flies. This result suggests a differential gene expression response to CH, which could affect muscle performance.These results suggest that dmDys is more sensitive to CH due to reduced muscle function and hypoxic stress response. Overall design: Adults wild type and dystrophic flies (3-5 days old) were exposed to hypobaric hypoxia for two weeks during the summer expedition to Mount McKinley, Alaska (6194 MASL). Another set of wild types and dystrophic flies were exposed to normobaric hypoxia according to the table I obtained during the climbing expedition. During the expedition, the flies were maintained in vials with regular molasses and covered by thermo isolation to avoid low temperature, keeping the temperature at 25C. The experiment performed in the laboratory also used vials with regular molasses and at 25C. Table I. Expedition log book for mount McKinley ascent. Information obtained during the ascent and summit of Mount McKinley, June 1st to June 16th of 2007. The oxygen pressure (PO2) was calculated from the barometric pressure. GNB means go and back from the mentioned point. DAY In order to understand the chronic hypoxia (CH) effect upon the absence of dystrophin, Drosophila melanogaster wild type and the model for DMD (dmDys), in which all dystrophins expression was knocked out by iRNA, were exposed to high altitude hypoxia (hypobaric hypoxia) during a 16-day climbing period reaching the summit of Mount McKinley (6194 meters above sea level). Furthermore, dmDys and Drosophila wild type were exposed to normobaric hypoxia (hypoxic chamber) following the same oxygen levels observed during the climbing expedition and to normoxic conditions for comparison. Affymetrix GeneChip® profiling was performed for individual flies from each experimental group. CH-dmDys differentially expressed 1281 genes, whereas control group differentially expressed 57 genes. Eight heat shock protein genes detected in the CH-dmDys microarray study were down-regulated, instead of up-regulated as seen in wild type hypoxic flies. This result suggests a differential gene expression response to CH, which could affect muscle performance.These results suggest that dmDys is more sensitive to CH due to reduced muscle function and hypoxic stress response. In order to understand the chronic hypoxia (CH) effect upon the absence of dystrophin, Drosophila melanogaster wild type and the model for DMD (dmDys), in which all dystrophins expression was knocked out by iRNA, were exposed to high altitude hypoxia (hypobaric hypoxia) during a 16-day climbing period reaching the summit of Mount McKinley (6194 meters above sea level). Furthermore, dmDys and Drosophila wild type were exposed to normobaric hypoxia (hypoxic chamber) following the same oxygen levels observed during the climbing expedition and to normoxic conditions for comparison. Affymetrix GeneChip® profiling was performed for individual flies from each experimental group. CH-dmDys differentially expressed 1281 genes, whereas control group differentially expressed 57 genes. Eight heat shock protein genes detected in the CH-dmDys microarray study were down-regulated, instead of up-regulated as seen in wild type hypoxic flies. This result suggests a differential gene expression response to CH, which could affect muscle performance.These results suggest that dmDys is more sensitive to CH due to reduced muscle function and hypoxic stress response. Overall design: Adults wild type and dystrophic flies (3-5 days old) were exposed to hypobaric hypoxia for two weeks during the summer expedition to Mount McKinley, Alaska (6194 MASL). Another set of wild types and dystrophic flies were exposed to normobaric hypoxia according to the table I obtained during the climbing expedition. During the expedition, the flies were maintained in vials with regular molasses and covered by thermo isolation to avoid low temperature, keeping the temperature at 25C. The experiment performed in the laboratory also used vials with regular molasses and at 25C. Table I. Expedition log book for mount McKinley ascent. Information obtained during the ascent and summit of Mount McKinley, June 1st to June 16th of 2007. The oxygen pressure (PO2) was calculated from the barometric pressure. GNB means go and back from the mentioned point. DAY LOCATION ALTITUDE m PO2 mmHg (%) 1 Base Camp 2200 123.6 (16.3%) 2 Base Camp 2200 123.6 (16.3%) 3 Base Camp 2200 123.6 (16.3%) 4 Ski Hill 2400 120.7 (15.9%) 5 Kahiltna Pass 2950 113.0 (14.9%) 6 Motorcycle Hill 3350 107.7 (14.2%) 7 Motorcycle Hill 3350 107.7 (14.2%) 8 GNB from Motorcycle 4150 (5 hours) 97.7 (12.9%) 9 Medical Camp 4350 95.3 (12.5%) 10 GNB from Medical Camp 4150 (5 hours) 97.7 (12.9%) 11 Medical Camp 4350 95.3 (12.5%) 12 GNB from Medical Camp 4900 89.0 (11.7%) 13 Medical Camp 4350 95.3 (12.5%) 14 High Camp 5250 85.1 (11.2%) 15 Summit 6194 (0.3 hours) 75.4 (9.9%) 16 High Camp 5250 85.1 (11.2%)
Project description:Transcriptional profiling of H1299 non-small cell lung carcinoma cells transfected with either wt p53 or mut(175) p53 driven by the 5xHRE promoter (5 repeats of hypoxia-inducible factor response elements) and treated for 16 h with normoxia (21% O2) or hypoxia(<0.1% O2). 5xHRE promoter ensures that p53 expression is induced in hypoxic conditions only. Goal was to determine the transcriptional response of p53 in hypoxia and the 175 p53 mutant was used as a control as it is DNA-binding defective and transcription-incompetent mutant. Four-condition experiment: wt p53-transfected H1299 cells treated with normoxia, mut p53-transfected H1299 cells treated with normoxia, wt p53-transfected H1299 cells treated with hypoxia, mut p53-transfected H1299 cells treated with hypoxia. Biological replicates: 1 normoxic sample with wt p53, 1 normoxic sample with mut p53, 3 hypoxic samples with wt p53, 3 hypoxic samples with mut p53.
Project description:Hypoxia is used as a model for pulmonary arterial hypertension. MiR-145 is upregulated in pulmonary arterial hypertension in humans and female mice. It has been observed that miR-145 knock out mice have reduced vascular remodelling in response to hypoxia. Therefore, knock down of miR-145 could be used as a therapy for pulmonary arterial hypertension in humans. This microarray has helped us to elucidate some of the pathways in the miR-145 knock out mice that may protect against vascular remodelling. Wild type (WT) mice and homozygous miR-145 -/- female mice (strain C57BL6J/129SVEV) at 8 weeks old were exposed to chronic hypoxia for 2 weeks or maintained in normoxic conditions and pulmonary arteries were dissected at 10 weeks of age. This study contained 4 groups, WT hypoxic, WT normoxic, miR-145 -/-, hypoxic miR-145 -/- normoxic each containing 6 animals. All adjacent comparisons were made to ananlyse the data (a 2 by 2 design).
Project description:How cancer cells adapt to hypoxia during tumor development remains an important question. The hypothesis tested in the present study was that tumor cell-derived exosome vesicles (also known as microvesicles or extracellular vesicles) are mediators of hypoxia-dependent intercellular signaling in glioblastoma (GBM), i.e. highly aggressive brain tumors characterized by hypoxia and a vascular density that is among the highest of all human malignancies. In vitro hypoxia experiments and studies with patient materials reveal the enrichment in exosomes of hypoxia-regulated mRNAs and proteins, several of which were associated with poor patient prognosis. We show that cancer cell exosomes mediate hypoxia-dependent, phenotypic modulation of stromal cells in vitro and ex vivo, resulting in accelerated GBM tumor angiogenesis and growth in mice. These data suggest that exosomes constitute potent mediators of hypoxia-driven tumor development, and circulating multiparameter biomarkers of tumor hypoxia. U87 MG glioblastoma cells were grown at normoxic (21% oxygen) or hypoxic (1% oxygen) conditions for 48 hours. Conditioned media from normoxic and hypoxic cells were then used to isolate exosomes by differential centrifugation. Both cells and exosomes were lysed in Trizol reagent, and RNA was isolated.Total RNA from all samples (four types of samples in three biological repilicates) was subjected to genome-wide transcriptional analysis with Illumina HumanHT-12 V3.0 expression beadchip. Gene expression profile obtained from hypoxic U87 MG glioblastoma cells was compared to the profile of normoxic control cells. Analogically, gene expression profile obtained from hypoxic U87 MG cells was compared to the profile of exosomes secreted by normoxic U87 MG cells.
Project description:Human HeLa cells were either kept in a hypoxic environment or under normoxic conditions. 137 proteins were found to be regulated, with maximum alteration of 18-fold. In particular, three clusters of differentially regulated proteins were identified, showing significant up-regulation of glycolysis and down-regulation of mitochondrial ribosomal proteins and translocases. This interaction is likely orchestrated by HIF-1. We also investigated the effect of hypoxia on the cell cycle, which is arrested at a restriction point in G1, and shows a prolonged S phase under these conditions.
Project description:Hypoxia promotes an aggressive tumor phenotype with increased genomic instability, partially due to downregulation of DNA repair pathways. However, in addition to DNA repair, genome stability is also controlled by cell cycle checkpoints. An important issue is therefore whether hypoxia also can alter the DNA damage cell cycle checkpoints. Here, we show that hypoxia (24h 0.2% O2) alters the expression of several G2 checkpoint regulators, as examined by microarray gene expression analysis and immunoblotting of U2OS cells. While some of the changes reflected hypoxia-induced inhibition of cell cycle progression, flow cytometric bar-coding analysis of individual cells showed that the levels of several G2 checkpoint regulators were reduced in G2 phase cells after hypoxic exposure, in particular cyclin B1. These effects were accompanied by decreased Cyclin dependent kinase (CDK) activity in G2 phase cells after hypoxia. Furthermore, cells pre-exposed to hypoxia showed a longer G2 checkpoint arrest upon treatment with ionizing radiation. Similar results were found following other hypoxic conditions (~0.03 % O2 20h and 0.2% O2 72h). These results demonstrate that the DNA damage G2 checkpoint can be altered as a consequence of hypoxia, and we propose that such alterations may influence the genome stability of hypoxic tumors. We measured gene expression changes in U2OS cells after treatment with 0.2% hypoxia for 24 hours. The data were used in the exploration of hyopxia induced alterations in the G2 checkpoint.
Project description:We demonstrate for the first time that under hypoxic conditions, A431 epithelial carcinoma cells exhibit increased viability when exposed to low-dose γ-irradiation, indicating that radiotherapy can promote tumor cell survival when oxygen supply is limited. When assessed using iTRAQ quantitative proteomics and Western blotting, irradiated tumor cells were observed to significantly up-regulate the expression of calcium-binding proteins CALM1, CALU and RCN1, suggesting important roles for these mediators in promoting tumor cell survival during hypoxia.