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Query: UMLS:C0242706 (hyperoxia)
 5,219 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Different DNA-damaging treatments produce a senescence-like phenotype. Young human fibroblasts are transferred to a senescence-like state after 4 to 6 weeks of culture under 40% ambient oxygen partial pressure. In order to understand the causes of senescence it would be advantageous to know how well this state equals accelerated senescence. Therefore, we measured the expression of genes with known senescence-specific expression pattern in human fibroblasts, which were irreversibly proliferation-inhibited by chronic hyperoxic treatment. A senescence-specific gene expression pattern was confirmed by semiquantitative RT-PCR for eight out of nine examined genes in BJ foreskin fibroblasts and for four out of four genes in MRC-5 lung fibroblasts. For all these cases, gene expression under hyperoxia was similar to that in senescent cells, suggesting that chronic mild hyperoxia is a valid model for accelerated senescence.
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PMID:Similar gene expression pattern in senescent and hyperoxic-treated fibroblasts. 982 40

A high concentration of oxygen can cause lung injury and lead to pulmonary fibrosis. Angiotensin (Ang) II induces human lung fibroblast proliferation and stimulates collagen synthesis. However, the role of the renin-angiotensin system (RAS) in the pathogenesis of hyperoxia-induced collagen production is unclear. The aims of this study were to investigate the effects of hyperoxia on the components of the RAS and collagen expression in human lung fibroblasts (MRC-5). Hyperoxia increased total collagen, collagen type I, and alpha-smooth muscle actin (alpha-SMA) mRNA and protein expression. RAS components and Ang II production were also significantly increased after hyperoxic exposure. Hyperoxia induced Ang II type 1 receptor (AT1R) expression but did not alter AT2R expression, furthermore, silencing of AT1R signaling with small interfering RNA suppressed hyperoxia-induced phosphorylated-ERK (p-ERK) 1/2, alpha-SMA, and collagen type I expression. Ang II increased p-ERK 1/2 and collagen type I expression, and these increases were inhibited by the AT1R inhibitor, losartan, but not by the AT2R inhibitor, PD123319 under both normoxic and hyperoxic conditions. These data suggest Ang II-mediated signaling transduction via AT1R is involved in hyperoxia-induced collagen synthesis in human lung fibroblasts.
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PMID:The renin-angiotensin system mediates hyperoxia-induced collagen production in human lung fibroblasts. 2035 22