{"owner": "ArrayExpress Uploader", "pop_total": 0, "species": "human", "factors": [{"GSM47049": {"GROWTH STAGE": "Young", "OXYGEN GROWTH CONDITIONS": "20%"}}, {"GSM47049": {"GROWTH STAGE": "Young", "OXYGEN GROWTH CONDITIONS": "20%"}}, {"GSM47049": {"GROWTH STAGE": "Young", "OXYGEN GROWTH CONDITIONS": "20%"}}, {"GSM470494": {"GROWTH STAGE": "Old", "OXYGEN GROWTH CONDITIONS": "20%"}}, {"GSM470494": {"GROWTH STAGE": "Old", "OXYGEN GROWTH CONDITIONS": "20%"}}, {"GSM470494": {"GROWTH STAGE": "Old", "OXYGEN GROWTH CONDITIONS": "20%"}}, {"GSM470497": {"GROWTH STAGE": "Young", "OXYGEN GROWTH CONDITIONS": "3%"}}, {"GSM470497": {"GROWTH STAGE": "Young", "OXYGEN GROWTH CONDITIONS": "3%"}}, {"GSM470497": {"GROWTH STAGE": "Young", "OXYGEN GROWTH CONDITIONS": "3%"}}, {"GSM470500": {"GROWTH STAGE": "Old", "OXYGEN GROWTH CONDITIONS": "3%"}}, {"GSM470500": {"GROWTH STAGE": "Old", "OXYGEN GROWTH CONDITIONS": "3%"}}, {"GSM470500": {"GROWTH STAGE": "Old", "OXYGEN GROWTH CONDITIONS": "3%"}}], "id": 3494, "ownerprofile_id": "arrayexpress_sid", "platform": 4, "summary_wrapped": "Senescent is an irreversible form of cell cycle arrest initiated by damaged cell constituents and subsequent pro-oncogenic signaling....", "geo_gse_id": "E-GEOD-19018", "owner_profile": "/profile/8773/arrayexpressuploader", "factor_count": 2, "sample_count": 12, "tags": ["cell"], "lastmodified": "Dec.12, 2014", "is_default": false, "geo_gds_id": "", "slug": "changes-in-gene-expression-of-imr90-cells-with-age", "geo_id_plat": "E-GEOD-19018_A-AFFY-44", "name": "Changes in gene expression of Imr90 cells with age and senescence under 3% and 20% oxygen growth conditions", "created": "Sep.15, 2014", "summary": "Senescent is an irreversible form of cell cycle arrest initiated by damaged cell constituents and subsequent pro-oncogenic signaling.  Replicative senescence in vitro can be considered a model for human aging.  When fibroblasts are cultured under atmospheric oxygen conditions of 20%, typical of normal tissue culture procedure, fibroblasts generally reach their replicative capacity at 50-60 population doublings (PDs).  When fibroblasts are cultured under normal physiological oxygen conditions of 3%, PDs increase about 30% relative to atmospheric levels.  Hence while oxygen is a requirement for normal aerobic respiration, it can contribute to the total amount of oxidative stress to which cells are exposed to, leading to a long-term adverse effect in vitro.  Inasmuch, cultures maintained under hyperoxic and hypoxic conditions provide a convenient model system for assessing the relationship between oxygen/oxidative stress and senescence. We used microarrays to profile the changes in global gene expression during aging and senescence of Imr90 cells under growth oxygen conditions of 3% and 20%. Imr90 cells at various population doubling timepoints (young, old, and senescent) grown seperately under 3 and 20% oxygen growth conditions were selected for RNA extraction and hybridization on Affymetrix microarrays.  Timepoints from cells grown under 3% and 20% oxygen conditions were age matched via population doublings to ensure accurate cross sample comparison.", "source": "http://www.ebi.ac.uk/arrayexpress/experiments/E-GEOD-19018", "sample_source": "http://www.ebi.ac.uk/arrayexpress/experiments/E-GEOD-19018/samples/"}