In this study, we examined whether asTF or flTF protects murine cardiomyocytes from TNF-伪-induced apoptosis. We used murine cardiomyocytic HL-1 cells and primary murine embryonic cardiomyocytes that overexpressed either murine asTF or murine flTF, and stimulated them with TNF-伪 to initiate cell death. Apoptosis was assessed by annexin-V assay, propidium iodide assay, as well as activation of caspase-3 and -9. In addition, signaling via integrins, Akt, NF魏B and Erk1/2, and gene-expression of Bcl-2 family members were analyzed.
We here report that overexpression of asTF reduced phosphatidylserine exposure upon TNF-伪-stimulation. asTF overexpression led to an increased expression and phosphorylation of Akt, as well as up-regulation of the anti-apoptotic protein Bcl-xL. The anti-apoptotic effects of asTF overexpression were mediated via 伪V尾3/Akt/NF魏B signaling and were dependent on Bcl-xL expression in HL-1 cells. The anti-apoptotic activity of asTF was also observed using primary cardiomyocytes. Analogous yet less pronounced anti-apoptotic sequelae were observed due to overexpression of flTF. Importantly, cardiomyocytes deficient in TF exhibited increased apoptosis compared to wild type cells.
We propose that asTF and flTF protect cardiomyocytes against TNF-伪-induced apoptosis via activation of specific signaling pathways, and up-regulation of anti-apoptotic members of the Bcl-2 protein family.