Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P30044 (antioxidant enzyme)
 8,037 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Reactive oxygen species are implicated in the development of gastrointestinal pathologies. Caco-2 monolayers are routinely used to study intestinal oxidative stress and its potential amelioration by pharmacological agents or dietary micronutrients. Little is known of the plasticity of Caco-2 antioxidant defenses with changes in culture conditions. We examined whether the frequency of culture media renewal alters the antioxidant-prooxidant status and integrity of Caco-2 monolayers. In comparison to monolayers subject to daily media renewal, increasing periods between media exchange resulted in varying degrees of suppression of catalase, glutathione reductase, and glutathione-S-transferase activity. No significant changes to superoxide dismutase activity, total glutathione, or intracellular ROS profiles were observed. Alkaline phosphatase activity, as a marker of differentiation, and mean monolayer cell population size were also unaffected. We suggest that Caco-2 antioxidant enzyme activities are differentially sensitive to changes in culture conditions. Studies employing this cell line for antioxidant-oxidative stress interactions will need to evaluate responses with respect to culture regime.
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PMID:Alteration of culture regime modifies antioxidant defenses independent of intracellular reactive oxygen levels and resistance to severe oxidative stress within confluent Caco-2 "intestinal cells". 1128 Nov 93

Accumulating data show that oxygen tension can have an important effect on cell function and fate. We used the human pre-osteoblastic cell line SV-HFO, which forms a mineralizing extracellular matrix, to study the effect of low oxygen tension (2%) on osteoblast differentiation and mineralization. Mineralization was significantly reduced by 60-70% under 2% oxygen, which was paralleled by lower intracellular levels of reactive oxygen species (ROS) and apoptosis. Following this reduction in ROS the cells switched to a lower level of protection by down-regulating their antioxidant enzyme expression. The downside of this is that it left the cells more vulnerable to a subsequent oxidative challenge. Total collagen content was reduced in the 2% oxygen cultures and expression of matrix genes and matrix-metabolizing enzymes was significantly affected. Alkaline phosphatase activity and RNA expression as well as RUNX2 expression were significantly reduced under 2% oxygen. Time phase studies showed that high oxygen in the first phase of osteoblast differentiation and prior to mineralization is crucial for optimal differentiation and mineralization. Switching to 2% or 20% oxygen only during mineralization phase did not change the eventual level of mineralization. In conclusion, this study shows the significance of oxygen tension for proper osteoblast differentiation, extra cellular matrix (ECM) formation, and eventual mineralization. We demonstrated that the major impact of oxygen tension is in the early phase of osteoblast differentiation. Low oxygen in this phase leaves the cells in a premature differentiation state that cannot provide the correct signals for matrix maturation and mineralization.
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PMID:Decreased oxygen tension lowers reactive oxygen species and apoptosis and inhibits osteoblast matrix mineralization through changes in early osteoblast differentiation. 2160 66