The Effects of Cell Culture Oxygen Levels on the Replicative Senescence Processes of Primary Human Fibroblasts

Abstract

Serial passaging of primary human fibroblasts leads to the formation of non-dividing senescent cells by a process termed replicative senescence. This tissue culture-based methodology is currently used to determine the underlying mechanisms involved in cellular aging and tumor suppression in vivo. Whether or not this model accurately reflects in vivo processes is presently controversial. Regardless, senescence is a universal process in mammalian cells and can be considered the cellular response to environmental stresses over time. Inasmuch, replicative senescence provides a methodology by which one can investigate the underlying causes of human cellular aging with respect to constant environmental stress over time. Our efforts are directed at understanding the molecular processes involved in cellular aging with specific emphasis on the role of the mitochondria. A series of experiments were performed to assess changes during the induction of replicative senescence under conditions of 3% and 20% oxygen, including transcriptional, protein kinase, and metabolic profiling.