MicroRNA-210-3p improves the survival potential of adult mouse cardiac progenitors Rita Alonaizan, Nicola Smart, Carolyn Carr Dept. of Physiology, Anatomy & Genetics, University of Oxford, Parks Rd, Oxford OX1 3PT
Although stem cell therapy has provided a promising treatment for myocardial infarction (MI), the low survival of the transplanted cells in the infarcted myocardium is a possible limitation to long-term improvement. Therefore, the development of strategies to enhance stem cell survival is of importance to this field. In this study, we examine the effects of the hypoxia miRNA miR-210-3p on serum-starved mouse cardiac progenitors. Adult mouse cardiac progenitors were expanded from the atria as slowly adhering collagenase-trypsin cells (CTs)1. Immunocytochemical analysis showed that CT cells express the mesenchymal progenitor markers cKit, CD44, Vim and PDGFRβ and were negative for the epicardial marker WT1. CT cell survival was assessed by serum starvation following transfection with miR-210-3p using DharmaFECT. We found that the over-expression of miR-210-3p decreased apoptosis in CTs, by decreasing poly-caspase activity and the number of TUNEL+ CTs in response to serum starvation (n=3). Moreover, the Bcl-2 adenovirus E1B 19 kDa-interacting protein 3 (Bnip3), which is regulated by HIF-1 and an inducer of mitophagy2, was upregulated by miR-210-3p in CTs under serum starvation (n=6). This led us to hypothesise that Bnip3-dependant mitophagy might serve an anti-apoptotic function in response to miR-210-3p overexpression. Therefore, mitophagy was assessed in serum-starved CTs by examining mitochondrial membrane potential, ROS levels, and the co-localisation of mitochondria with the autophagy machinery after miR-210-3p transfection.
1. Malandraki-Miller, S., Tyser, R., Riley, P. R. & Carr, C. A. COMPARATIVE CHARACTERIZATION OF CARDIAC ATRIAL PROGENITOR CELL POPULATIONS FOR USE IN CELL THERAPY. Heart100, A14 LP-A14 (2014). 2. Zhang, H. et al. Mitochondrial Autophagy Is an HIF-1-dependent Adaptive Metabolic Response to Hypoxia. J. Biol. Chem.283, 10892-10903 (2008).
Funded by the King Faisal Specialist Hospital and Research Centre (KFSHRC).