Preconditioning Promotes Survival and Angiomyogenic Potential of Mesenchymal Stem Cells in the Infarcted Heart via NF-κB Signaling

We proposed that pharmacological manipulation of mesenchymal stem cells (MSCs) with diazoxide enhanced their survival and regenerative potential via NF kappa B regulation. MSCs preconditioned ((MSCs)-M-PC) with diazoxide and later subjected to oxidant stress with 100 mu mol/L H2O2 either immediately or after 24 h exhibited higher survival (p < 0.01 vs nonpreconditioned MSCs; Non-PCMSCs) with concomitantly increased phosphorylation of PI3K, Akt, GSK3 beta (cytoplasmic), and NF-kappa B (p65) (nuclear). Akt kinase activity was determined as a function of GSK3 beta activity. Pretreatment of (MSCs)-M-PC with Wortmannin (Wt), NEMO-binding domain (NBD), or NF-kappa B (p50) siRNA abolished v (p65) activity. Preconditioning increased NF-kappa B-dependent elevation of secretable growth factors associated with their paracrine effects. Inhibition of PI3K activity with Wt reduced (MSCs)-M-PC viability at both early and 24 h time-points. However, inhibition of NF-kappa B reduced viability of (MSCs)-M-PC only at 24 h time-point. For in vivo studies, DMEM without cells (group-1) or containing 1 x 10(6) male Non-PCMSCs (group-2), (MSCs)-M-PC (group-3), (MSCs)-M-PC pretreated with Wortmannin (group-4) or NF-kappa B decoy (group-5) were transplanted in a female rat model of acute myocardial infarction. Group-3 showed highest cell survival and growth factor expression, increased angiomyogenesis, and functional improvement. We conclude that activation of NF-kappa B by preconditioning promoted (MSCs)-M-PC survival and angiomyogenic potential in the infarcted heart. Antioxid. Redox Signal. 12, 693-702.