Abstract 15151: The Role of Microrna-145 in Human Embryonic Stem Cell Differentiation Into Smooth Muscle Cells
Introduction: Recent studies have reported that microRNA-145 (miR-145) is a critical mediator in the regulation of proliferation, differentiation, and phenotype of smooth muscle cells (SMCs). Previously, we established a system for differentiating human embryonic stem (ES) cells into vascular cells including endothelial cells (ECs) and smooth muscle cells (SMCs) (ATVB 27(10):2127–34, 2007). In this study, we investigated the role of miR-145 in the differentiation process from human ES cells to SMCs.
Methods and Results Undifferentiated human ES cell line KhES-1 was induced to differentiate to SMCs using coculture with OP9 feeder cells. Quantitative RT-PCR analysis revealed that, similar to human adult vascular SMCs (VSMCs), significant amount of miR-145 was expressed in human ES cell-derived SMCs (ES-SMCs), compared to undifferentiated human ES cells, adult ECs, or ES cell-derived ECs. However, immunocytochemistry revealed that not all ES-SMCs were positive for smooth muscle markers including α-SMA and SM-MHC 1,2, indicating not all ES-SMCs properly differentiated to SMCs. To induce mature SMCs, upregulation of miR-145 via electroporation of pre-miR-145 (100nM) on ES-SMCs was performed. Overexpression of miR-145 in ES-SMCs significantly increased the number of SMC marker-positive cells. In addition, because miR-145 induces synthetic to contractile phenotype, ES-SMCs proliferation induced by platelet-derived growth factor BB was significantly inhibited by miR-145 overexpression. Furthermore, carbachol-stimulated contraction of ES-SMCs was significantly increased by pre-miR-145 treatment.
Conclusion: We showed that miR-145 was abundant in our human ES-SMCs, although not all ES-SMCs properly differentiated. Overexpression of miR-145 on human ES-SMCs would become a promising method to obtain functional mature SMCs from human ES cells.
- © 2010 by American Heart Association, Inc.