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Stem Cells International
Volume 2017, Article ID 8286248, 15 pages
https://doi.org/10.1155/2017/8286248
Research Article

Different Effects of Insulin-Like Growth Factor-1 and Insulin-Like Growth Factor-2 on Myogenic Differentiation of Human Mesenchymal Stem Cells

Doaa Aboalola1,2,3,4 and Victor K. M. Han1,2,3,5

1Department of Anatomy and Cell Biology, Schulich School of Medicine and Dentistry, University of Western Ontario, London, ON, Canada
2Children’s Health Research Institute, University of Western Ontario, London, ON, Canada
3Lawson Health Research Institute, University of Western Ontario, London, ON, Canada
4King Abdullah International Medical Research Center, National Guard Health Affairs, Jeddah, Saudi Arabia
5Department of Paediatrics, Schulich School of Medicine and Dentistry, University of Western Ontario, London, ON, Canada

Correspondence should be addressed to Victor K. M. Han; ac.no.cshl@nah.rotciv

Received 3 August 2017; Revised 28 September 2017; Accepted 10 October 2017; Published 14 December 2017

Academic Editor: Luca Vanella

Copyright © 2017 Doaa Aboalola and Victor K. M. Han. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Insulin-like growth factors (IGFs) are critical components of the stem cell niche, as they regulate proliferation and differentiation of stem cells into different lineages, including skeletal muscle. We have previously reported that insulin-like growth factor binding protein-6 (IGFBP-6), which has high affinity for IGF-2, alters the differentiation process of placental mesenchymal stem cells (PMSCs) into skeletal muscle. In this study, we determined the roles of IGF-1 and IGF-2 and their interactions with IGFBP-6. We showed that IGF-1 increased IGFBP-6 levels within 24 hours but decreased after 3 days, while IGF-2 maintained higher levels of IGFBP-6 throughout myogenesis. IGF-1 increased IGFBP-6 in the early phase as a requirement for muscle commitment. In contrast, IGF-2 enhanced muscle differentiation as shown by the expression of muscle differentiation markers MyoD, MyoG, and MHC. IGF-1 and IGF-2 had different effects on muscle differentiation with IGF-1 promoting early commitment to muscle and IGF-2 promoting complete muscle differentiation. We also showed that PMSCs acquired increasing capacity to synthesize IGF-2 during muscle differentiation, and the capacity increased as the differentiation progressed suggesting an autocrine and/or paracrine effect. Additionally, we demonstrated that IGFBP-6 could enhance the muscle differentiation process in the absence of IGF-2.