Propofol affects mouse embryonic fibroblast survival and proliferation in vitro via ATG5- and calcium-dependent regulation of autophagy

Abstract

Propofol is a commonly used intravenous anesthetic agent, which has been found to affect cell survival and proliferation especially in early life. Our previous studies show that propofol-induced neurodegeneration and neurogenesis are closely associated with cell autophagy. In the present study we explored the roles of autophagy-related gene 5 (ATG5) in propofol-induced autophagy in mouse embryonic fibroblasts (MEF) in vitro. We showed that ATG5 was functionally related to propofol-induced cell survival and damage: propofol significantly enhanced cell survival and proliferation at a clinically relevant dose (10 µM), but caused cell death at an extremely high concentration (200 µM) in ATG5−/− MEF, but not in WT cells. The dual effects found in ATG5−/− MEF could be blocked by intracellular Ca2+ channel antagonists. We also found that propofol evoked a moderate (promote cell growth) and extremely high (cause apoptosis) cytosolic Ca2+ elevation at the concentrations of 10 µM and 200 µM, respectively, only in ATG5−/− MEF. In addition, ATG5−/− MEF themselves released more Ca2+ in cytosolic space and endoplasmic reticulum compared with WT cells, suggesting that autophagy deficiency made intracellular calcium signaling more vulnerable to external stimuli (propofol). Altogether, our results reveal that ATG5 plays a crucial role in propofol regulation of cell survival and proliferation by affecting intracellular Ca2+ homeostasis.