14-3-3γ protein attenuates lipopolysaccharide-induced cardiomyocytes injury through the Bcl-2 family/mitochondria pathway

Previous studies have indicated that 14-3-3 gamma is upregulated by stress in LPS-induced cardiovascular injury. In this study, we investigated the interaction of 14-3-3 gamma and Bcl-2 family members in the control of the mitochondrial permeability transition (MPT) to test the hypothesis that abundant levels of 14-3-3 gamma can protect against LPS-induced injury via a Bcl-2 family/mitochondria pathway. The cardiomyocytes were treated with LPS (1 mg l(-1)) for 6 h; the interaction between 14-3-3 gamma and phospho-Bad(S112) was detected by co-immunoprecipitation (coIP); the levels of Bcl-2 family members in the cytosolic and mitochondrial fractions were examined by Western blot; the apoptosis and mitochondrial membrane potential (Delta Psi m) were detected by flow cytometry; and the mitochondrial permeability transition pore (mPTP) opening was tested by mitochondria(swelling. Our results revealed that LPS treatment results in cardiomyocyte injury, and these effects were significantly attenuated by pFLAG-14-3-3 gamma. Moreover, LPS treatment induced Bax translocation to the mitochondria, Delta Psi m loss, mitochondrial swelling, and cytochrome c release, and pFLAG-14-3-3 gamma reversed these effects induced by LPS. Moreover, overexpressed 14-3-3 gamma protein could assist Bad(S112) phosphorylation and interact with it to form a complex, which might result in the disassociation of Bcl-2 from the Bad/Bcl-2 complex and its translocation from the cytosol to the mitochondria. Our data firstly confirmed that a high level of 14-3-3 gamma protects against LPS-induced cardiomyocyte injury likely through a pathway associated with the regulation of the subcellular localizations of Bcl-2 and Bad that results in the prevention of mPTP opening, the maintenance of Delta Psi m, and ultimately the inhibition of apoptosis. (C) 2014 Elsevier B.V. All rights reserved.