Insulin-like growth factor-II overexpression accelerates parthenogenetic stem cell differentiation into cardiomyocytes and improves cardiac function after acute myocardial infarction in mice

• Main Authors: Yi Sui, Wei Zhang, Tao Tang, Lili Gao, Ting Cao, Hongbo Zhu, Qinghua You, Bo Yu, Tao Yang
• Format: Article
• Language: English
• Published: BMC 2020-02-01
• Series: Stem Cell Research & Therapy
• Subjects: Parthenogenetic stem cells; Insulin-like growth factor-II; Differentiation; Cardiomyocytes; Acute myocardial infarction
• Online Access: http://link.springer.com/article/10.1186/s13287-020-1575-4

Abstract Background Parthenogenetic stem cells (PSCs) are a promising source of regenerated cardiomyocytes; however, their application may be limited without a paternal genome. Insulin-like growth factor-II (IGF-II), a paternally expressed growth hormone, is critical in embryonic differentiation. This study investigated whether forced expression of IGF-II in PSCs can accelerate their differentiation. Methods Overexpression and re-knockdown of IGF-II in PSCs were performed to investigate the role of IGF-II in PSC differentiation. The derivatives of PSCs with different IGF-II manipulations were transplanted into infarcted murine hearts to investigate the role of IGF-II in cardiomyocyte differentiation in vivo. Results Data showed that the expression of cardiac troponin T and troponin I in IGF-II-PSC outgrowths preceded that of parental PSC outgrowths, suggesting that IGF-II can accelerate PSC differentiation into cardiac lineage. Overexpression of IGF-II accelerated PSC differentiation towards cardiomyocytes while inhibiting PSC proliferation via the IGF-II/IGF1R signaling. Similar to that observed in cardiac marker expression, on differentiation day 24, IGF-II-PSCs showed PCNA and cyclin D2 expression comparable to juvenile mouse cardiomyocytes, showing that IGF-II-PSCs at this stage possess differential and proliferative properties similar to those of juvenile cardiomyocytes. Moreover, the expression pattern of cardiac markers in IGF-II-overexpressing PSC derivatives resembled that of juvenile mouse cardiomyocytes. After transplantation into the infarcted mouse hearts, IGF-II-PSC-derived cardiomyocytes displayed significant characteristics of mature cardiomyocytes, and IGF-II-depletion by shRNA significantly reversed these effects, suggesting the critical role of IGF-II in promoting cardiomyocyte maturation in vivo. Furthermore, IGF-II-overexpressing PSC derivatives reduced collagen deposition and mitochondrial damage in the infarcted areas and improved cardiac function. The re-knockdown of IGF-II could counteract these favorable effects of IGF-II. Conclusions These findings suggest that the ectopic expression of IGF-II accelerates PSC differentiation into the cardiac lineage and promotes cardiomyocyte maturation. The underlying process includes the IGF-II/IGF1R signaling, which is involved in the suppressive effect of IGF-II on PSC proliferation. Moreover, transplanting IGF-II-overexpressing PSC derivatives into the infarcted heart could reduce collagen deposition and improve mitochondria biogenesis and measurements of cardiac function, highlighting the importance of IGF-II in the application of PSCs in cardiac regeneration.