Theme and Variation: Proteomic Changes Across Three Organs in Hibernation Cycles of the 13-Lined Ground Squirrel

Circannual hibernation is characterized by two cycles—the annual cycle between summer homeothermy and winter heterothermy as well as the individual torpor-arousal cycles within winter heterothermy. We hypothesized that proteins and pathways that promote or enhance survival throughout hibernation cycles are concordantly regulated in organs throughout the body. In this study, we applied a meta-analysis to previously described proteomic changes in six identical seasonal and physiological states of heart, skeletal muscle, and kidney in order to identify common protective mechanisms underlying resistance to challenges of hibernation. Unexpectedly, we detected little overlap among organs. In heart, few protein spots changed in abundance among the six states, while in kidney more than half of the spots detected differed among these same states. Only two significantly changing proteins were shared among all three datasets, and of proteins common between any two organs, many were discordant for abundance pattern changes among states. In sum, most proteomic changes accompanying hibernation appear to be organ-specific.