Methamphetamine induces autophagy as a pro-survival response against apoptotic endothelial cell death through the Kappa opioid receptor

Ma, J; Wan, J; Meng, J; Banerjee, S; Ramakrishnan, S; Roy, S

Previous studies have shown that formation of a Beclin1/ Bcl-2 complex may function as a rheostat that regulates autophagic capacity and ensures that autophagy levels remain within a homeostatic range. 17 To determine whether METH treatment affected Beclin1 and Bcl-2 expression, total cellular levels of each protein were analyzed by western blots (Figure 2b ). Beclin1 levels increased around sixfold, whereas Bcl-2 levels decreased over the period of METH treatment ( Figure 2c ). The expression of Beclin1 was induced at 24 and 48 h of exposure, indicating induction of autophagy in METHtreated cells. To address the possibility that METH-modulated Beclin1 expression and the interaction with Bcl-2, Beclin1/Bcl-2 complexes were immunoprecipitated with antibodies against Beclin1. The western blots in Figures 2d and e showed that in control cells Bcl-2 co-immunoprecipitated with Beclin1 which decreased following 24 h of METH treatment. Together, these results suggested that METH-induced autophagy in endothelial cells was mediated by upregulating Beclin1 expression and disrupting the balance between Beclin1 and Bcl-2.