Bone marrow derived stromal cells modified by adenovirus-mediated HIF-1alpha double mutant protect cardiac myocytes against CoCl2-induced apoptosis

Bone marrow derived stromal cells (MSCs) can prevent the apoptosis of ischemic cardiomyocytes (CMCs). This anti-apoptosis activity may be related to an activation of the HIF-1alpha signal pathway in MSCs. Therefore, we investigated protective effects of an adenovirus (Ad)-mediated active form of HIF-1alpha (HIF-1alpha-Ala564-Ala803) modified MSCs on CMCs against CoCl(2)-induced apoptosis. At normoxia, pAd-HIF1alpha-Ala564-Ala803 exhibited a stable HIF-1alpha protein expression in MSCs. Compared with the single CMC culture, the TGF-beta1 level and the Bcl-2 expression were significantly increased, concomitant with a reduced expression of caspase-3, the LDH release and TUNEL-positive CMCs in CMC and MSC, beta-galactosidase (LacZ)-MSC or HIF-1alpha-Ala564-Ala803-MSC coculture exposed to CoCl(2). Furthermore, these effects were more prominent in CMC and HIF-1alpha-Ala564-Ala803-MSC coculture than in CMC and MSC or LacZ-MSC coculture exposed to CoCl(2). Pre-transfection of TGF-beta1-small interfering RNA (siRNA) effectively inhibited the TGF-beta1 level, resulting in a dramatic reduction in the Bcl-2 expression as well as an increased level of apoptosis in CMC and HIF-1alpha-Ala564-Ala803-MSC coculture exposure to CoCl(2), whereas pre-transfection of green fluorescent protein (GFP)-siRNA had no such effects. These data suggest that HIF1alpha-Ala564-Ala803 modified MSCs have better protective effects of CMCs against the CoCl(2)-induced apoptosis and these protective effects are at least partly TGF-beta1-mediated.