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WI-38 Fibroblasts (wi-38 + fibroblast)
Selected AbstractsAppearance of biomarkers of in vitro ageing after successive stimulation of WI-38 fibroblasts with IL-1, and TNF-,: senescence associated ,-galactosidase activity and morphotype transitionJOURNAL OF ANATOMY, Issue 4 2000PATRICK DUMONT Sublethal oxidative stresses increase the proportions of human fibroblasts positive for senescence associated ,-galactosidase activity and accelerate the transition in the fibroblast morphotypes characterising fibroblast ageing. Stimulation of fibroblasts with TNF-, or IL-1, transiently increases the production of reactive oxygen species (ROS) in human fibroblasts. Here we propose that repeated stimulation of WI-38 fibroblasts with TNF-, or IL-1, can generate enough ROS to accelerate the transition in the fibroblast morphotypes and increase the proportion of cells positive for senescence associated ,-galactosidase activity. The involvement of ROS is suggested by experiments where the stimulation of fibroblasts with TNF-, or IL-1, are performed in the presence of N-acetylcysteine which increases the intracellular antioxidant potential. It is proposed that the decrease in the proportions of morphotypes I and II, and the increase in the proportions of morphotypes III to VI observed after successive stimulation with TNF-, or IL1-, is attributed to an increased ROS production occurring during the stimulation. [source] Protein modification and replicative senescence of WI-38 human embryonic fibroblastsAGING CELL, Issue 2 2010Emad K. Ahmed Summary Oxidized proteins as well as proteins modified by the lipid peroxidation product 4-hydroxy-2-nonenal (HNE) and by glycation (AGE) have been shown to accumulate with aging in vivo and during replicative senescence in vitro. To better understand the mechanisms by which these damaged proteins build up and potentially affect cellular function during replicative senescence of WI-38 fibroblasts, proteins targeted by these modifications have been identified using a bidimensional gel electrophoresis-based proteomic approach coupled with immunodetection of HNE-, AGE-modified and carbonylated proteins. Thirty-seven proteins targeted for either one of these modifications were identified by mass spectrometry and are involved in different cellular functions such as protein quality control, energy metabolism and cytoskeleton. Almost half of the identified proteins were found to be mitochondrial, which reflects a preferential accumulation of damaged proteins within the mitochondria during cellular senescence. Accumulation of AGE-modified proteins could be explained by the senescence-associated decreased activity of glyoxalase-I, the major enzyme involved in the detoxification of the glycating agents methylglyoxal and glyoxal, in both cytosol and mitochondria. This finding suggests a role of detoxification systems in the age-related build-up of damaged proteins. Moreover, the oxidized protein repair system methionine sulfoxide reductase was more affected in the mitochondria than in the cytosol during cellular senescence. Finally, in contrast to the proteasome, the activity of which is decreased in senescent fibroblasts, the mitochondrial matrix ATP-stimulated Lon-like proteolytic activity is increased in senescent cells but does not seem to be sufficient to cope with the increased load of modified mitochondrial proteins. [source] Nuclear accumulation of glycogen synthase kinase-3 during replicative senescence of human fibroblastsAGING CELL, Issue 5 2004Jaroslaw W. Zmijewski Summary Activation of the tumor suppressor protein p53 contributes to cellular senescence. As glycogen synthase kinase-3 (GSK3) was recently found to interact with p53 and contribute to the actions of p53, this study examined whether GSK3 accumulated in the nucleus and associated with p53 in senescent cells. Compared with young and middle-aged human WI-38 fibroblasts, senescent cells were found to contain increased nuclear levels of GSK3,, and also tended to accumulate in the nucleus the other isoform of GSK3, GSK3,. Co-immunoprecipitation experiments demonstrated that GSK3, and p53 formed a complex in the nucleus. Further experiments tested whether inhibition of GSK3 altered the development of senescence using long-term treatment with the selective GSK3 inhibitor lithium. Lithium treatment reduced the senescence-associated accumulation of p53 and caused cells to enter a reversible quiescent state. These results indicate that a portion of the p53 that is activated in senescent cells is modulated by its association with GSK3, in the nucleus, an association that is known to facilitate the actions of p53 and that may contribute to senescence. [source] | ||||||||||