SRT1720 promotes survival of aged human mesenchymal stem cells via FAIM: a pharmacological strategy to improve stem cell-based therapy for rat myocardial infarction

SIRT1 has been proved to rejuvenate and improve the therapeutic efficacy of aged rat mesenchymal stem cells (MSCs). Herein, we investigate the protective effect of pretreatment with SIRT1 activator SRT1720 on aged human MSCs (hMSCs). The optimized pretreatment condition for aged hMSCs was determined to be 0.5 μM SRT1720 for 24 h by monitoring the survival of aged hMSCs subjected to serum deprivation±hypoxia and±500 μM hydrogen peroxide (H2O2). Pretreatment with these conditions increased the survival of aged hMSCs 1 day (2.7-fold) and 3 days (1.9-fold) after being transplanted into a rat myocardial infarction (MI) model created by ligation of the left anterior descending (LAD) coronary artery. Transplantation with SRT1720 pretreated aged hMSCs achieved increased left ventricular ejection fraction (58.9±3.6 versus 52.8±5%) and angiogenesis with reduced fibrosis of rat hearts as compared to DMSO pretreated group 28 days following MI. Unbiased transcriptome analysis conducted on aged hMSCs under oxidative stress indicated the Fas apoptosis inhibitory molecule (FAIM) was significantly upregulated following SRT1720 pretreatment (14.9±0.2-folds). Moreover, the anti-apoptotic effect of SRT1720 was mitigated by FAIM knockdown with a small interfering RNA-targeted FAIM. These results indicated that pretreatment with SRT1720 improves survival of aged hMSCs, and enhances their therapeutic efficacy for rat myocardial infarction (MI). Upregulation of FAIM possibly involves in the mechanisms of the protective effects.