P04 : Role of antiapoptotic signaling in mammalian hibernation

Abstract

In the context of normal cell turnover, apoptosis is an essential natural phenomenon. Apoptosis depends on signals that promote cell death – proapoptotic pathways “and those that neutralize these signals” anti-apoptotic pathways. We proposed that changes in anti-apoptotic proteins would counteract stresses associated with hibernation (e.g. cold body temperatures, changes in metabolic requirements, ischemia–reperfusion) in thirteen-lined ground squirrels ( Spermophilus tridecemlineatus ). Immunoblotting was used to analyze expression of proteins in three tissues. In brain, phospho-Bcl-2 (T56), phospho-Bcl-2(S70), Bcl-3, xIAP, Mcl-1, and BI-1 increased significantly during torpor (compared with euthermia) whereas cIAP was unaltered. In liver, all proteins were unchanged except for cIAP and Bcl-3 that decreased and BI-1 which increased during torpor. In kidney, the majority of proteins did not change except for a decrease in phospho-Bcl-2(T56) and an increase in BI-1 during torpor. The data show that anti-apoptotic pathways have organ-specific responses in hibernators with a prominent potential role in brain.