S.I.S. Rattan

In a series of experimental studies we have shown that repetitive mild heat stress has anti-ageing hormetic effects on growth and various other cellular and biochemical characteristics of human skin fibroblasts undergoing ageing in vitro. We have reported the hormetic effects of repeated challenge at the levels of maintenance of stress protein profile, reduction in the accumulation of oxidatively and glycoxidatively damaged proteins, stimulation of the proteasomal activities for the degradation of abnormal proteins, improved cellular resistance to ethanol, hydrogenperoxide and ultraviolet-B rays, and enhanced levels of various antioxidant enzymes. We are now undertaking detailed analysis of the signal transduction pathways in order to determine alterations in the phosphorylation and dephosphorylation states of ERK, JNK and p38 MAP-kinases as a measure of cellular responsiveness to mild and severe heat stress. Furthermore, we are also undertaking comparative studies using non-ageing immortal cell lines, such as SV40-transformed human fibroblasts, spontaneous osteosarcoma cells and telomerase-immortalised human bone marrow cells for establishing differences in normal and cancerous cells with respect to their responsiveness to mild and severe stresses.

Keywords (Optional): 
cellular aging
heat shock