Background:
Older age is the major risk factor for heart failure, and reprogramming a patient’s own cells to produce induced pluripotent stem cells (iPSCs) is a promising strategy for autologous cell transplantation therapy. However, low reprogramming efficiency of senescent cells remains as a major pitfall. Recently, our preliminary data suggested that inhibiting senescence-associated miR-195 rejuvenated aged stem cells by reactivating anti-aging defense system. This study investigated the effects of blocking miR-195 expression on the reprogramming efficiency of old skeletal myoblasts (OSkMs).
Methods and Results:
MiR-195 expression was significantly higher in OSkMs isolated from aged mice (24 months) as compared to those from young mice (2 months), as examined by RT-PCR. OSkMs showed impaired expression of anti-aging factors (Tert and Sirt1) and higher expression of pro-aging markers (p53, p21, p16). Intriguingly, blocking miR-195 expression in OSkMs by transfection with anti-miR-195 significantly induced restoration of Tert and Sirt1 as well as telomere re-lengthening as examined by RT-PCR and quantitative fluorescent in situ hybridization. Luciferase assay confirmed that Sirt1 is one of the direct targets of miR-195 relevant to senescence of OSkMs. Importantly, lower reprogramming efficiency of OSkMs was significantly improved by miR-195 abrogation without altering karyotype or expression of pluripotency markers. Furthermore, iPSCs lacking miR-195 successfully differentiated into all three germ layers, indicating that deletion of miR-195 does not affect pluripotency. Notably, contraction rates were markedly higher in beating cells transfected with anti-miR-195 as compared to that with scramble (68.5±5.6 vs 47.3±2.8/min).
Conclusions:
Blocking age-induced miR-195 is a novel promising approach for efficient iPSCs generation from senescent cells, which has beneficial for autologous transplantation of iPSCs in elderly patients.
Proteins Reprogramming: Present and Future
