Roles of microRNA-34a targeting SIRT1 in mesenchymal stem cells

Abstract

IntroductionMesenchymal stem cell (MSC)-based therapies have had positive outcomes both in animal models of cardiovascular diseases and in clinical patients. However, the number and function of MSCs decline during hypoxia and serum deprivation (H/SD), reducing their ability to contribute to endogenous injury repair. MicroRNA-34a (miR-34a) is originally identified as a TP53-targeted miRNA that modulates cell functions, including apoptosis, proliferation, and senescence via several signaling pathways, and hence is an appealing target for MSC-based therapy for myocardial infarction.MethodsBone marrow-derived MSCs were isolated from 60–80 g male donor rats. Expression levels of miR-34a were determined by qRT-PCR. The roles of miR-34a in regulating cell vitality, apoptosis and senescence were investigated using the cell counting kit (CCK-8) assay, flow cytometric analysis of Annexin V-FITC/PI staining and senescence-associated β-galactosidase (SA-β-gal) staining, respectively. The expression of silent information regulator 1 (SIRT1) and forkhead box class O 3a (FOXO3a) and of apoptosis- and senescence-associated proteins in MSCs were analyzed by western blotting.ResultsThe results of the current study showed that miR-34a was significantly up-regulated under H/SD conditions in MSCs, while overexpression of miR-34a was significantly associated with increased apoptosis, impaired cell vitality and aggravated senescence. Moreover, we found that the mechanism underlying the proapoptotic function of miR-34a involves activation of the SIRT1/FOXO3a pathway, mitochondrial dysfunction and finally, activation of the intrinsic apoptosis pathway. Further study showed that miR-34a can also aggravate MSC senescence, an effect which was partly abolished by the reactive oxygen species (ROS) scavenger, N-acetylcysteine (NAC).ConclusionsOur study demonstrates for the first time that miR-34a plays pro-apoptotic and pro-senescence roles in MSCs by targeting SIRT1. Thus, inhibition of miR-34a might have important therapeutic implications in MSC-based therapy for myocardial infarction.

Geraniin Inhibits LPS-Induced THP-1 Macrophages Switching to M1 Phenotype via SOCS1/NF-κB Pathway

“…The cells were treated with geraniin for 2 h prior to the addition of LPS and subsequently incubated for 24 h. Total protein was extracted, and western blot analysis was performed as previously described [20]. The blots were incubated with primary antibodies against nuclear factor kappa B p65 (NF-κB-p65), phospho-NF-κB-p65, IκB-α (Beyotime Institute of Biotechnology, Jiangsu, China), and SOCS1 (Cell Signaling Technology, Danvers, MA, USA) at 4°C overnight.…”

Emergence of miR-34a in radiation therapy

“…Interestingly, several studies showed that miR-34a mimics increased, and antisense miR-34a inhibited, in vitro ROS production (Bai et al, 2011; Ferreira et al, 2014; S.-Z. Li et al, 2014; F. Zhang et al, 2015) in several cell lines, suggesting a direct role of miR-34a in oxidative stress.…”

Harnessing the Power of SIRT1 and Non-coding RNAs in Vascular Disease

“…Neuronal differentiation can occur through miR-34a that leads to decreased SIRT1 expression and DNA-binding of p53 in mouse neural stem cells (134). Furthermore, miR-34a under other conditions that increase the SIRT1 and FoxO3a pathways can result in mitochondrial dysfunction and activation of intrinsic apoptotic pathways that are detrimental to mesenchymal stem cells (135). …”