TGF-β1 induces senescence of bone marrow mesenchymal stem cells via increase of mitochondrial ROS production

Background: Bone marrow derived mesenchymal stem cells (bmMSCs) are multipotent cells that can differentiate into diverse cell types, including cardiomyocytes. BmMSC-based transplantation is capable of repairing acute and chronic myocardial infarction. Prior to the transplantation, MSCs are usually induced in vitro by biological reagents and chemicals for directional differentiation. Transforming growth factor beta (TGF-beta) is one of the most commonly used biological reagents for induction of cardiomyocyte differentiation of bmMSCs. Previous studies have shown that TGF-beta induces senescence in several cell types. However, whether TGF-beta affects senescence of bmMSCs has not been elucidated. The goal of this study was to investigate the effect of TGF-beta 1 on senescence of bmMSCs and the underlying mechanisms. Results: We found that TGF-beta 1 increased activity of senescence-associated-galactosidase (SA-Gal) and production of mitochondrial reactive oxygen species (mtROS) in bmMSCs in a dose-dependent manner. TGF-beta 1 also significantly decreased expression of superoxide dismutase 2 (SOD2) and Id1, and increased expression of 4-Hydroxynonenal (4-HNE) subunits and p16 in bmMSCs in a dose-dependent manner. Pre-treatment with mtROS inhibitor acetyl-L-carnitine (ALCAR, 0.1 mM) significantly inhibited TGF beta 1-induced mtROS production and SA-Gal activity. Conclusion: TGF-beta 1 can induce senescence of bmMSCs, which at least partially depends on mtROS production.