Controlling Aging Restoration of Cellular Senescence

Abstract

Senescence is defined as an irreversible cell-cycle arrest and is the main driving-force of aging and age-related diseases. Recently, the reversal of senescence has been suggested as a promising target for rejuvenating organism or alleviating age-related pathologies. Cell physiology is regulated by complex signal pathways in which various kinase are involved. We hypothesized that aged altered cell physiology could be restored by modulating kinase activity, and performed high-throughput screening (HTS) with kinase inhibitor library to find compounds that can reverse senescence. From the chemical screening for agents that dismantle the cell cycle arrest of senescent cells and ameliorate aged-related phenotypic changes such as elevated SA-b-gal activity and reactive oxygen species concentration, Ataxia telangiectasia mutated (ATM) inhibitor as well as rho-associated, coiled-coil-containing protein kinase (ROCK) inhibitors were identified as effective agents. Since the role of ATM or ROCK in senescence remains elusive, the identification of novel interacting partners with these kinases would provide clues toward revealing its function in senescence and furthermore deciphering mode of action in reverting senescence by the kinase inhibitors. A yeast two-hybrid screen and further analysis confirmed that a subunit of vascular ATPase complex and a protein belonging to Rho family of GTPase are a novel substrate for ATM and ROCK, respectively. Attenuation of the aged-related kinase activation by the screened inhibitors reduced phosphorylation of the substrate protein, which induced functional recovery of lysosomes or mitochondria where the substrate is located. Our data revealed a novel mechanism in which reversal of senescence is controlled by the recovered lysosomal-mitochondrial axis upon adjustment of kinase activity.