Interaction Between Murine Cardiac Stem Cells And Bone Marrow-Derived Mesenchymal Stem Cells For Cardiomyocyte Differentiation In Vitro
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Date
2016-01
Authors
Leong, Yin Yee
Journal Title
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Publisher
Universiti Sains Malaysia
Abstract
Background: Bone marrow-derived mesenchymal stem cells (MSCs) has been shown to facilitate heart repair via activation of endogenous cardiac stem cells (CSCs) following infarction, but little is known if the synergy of the two cells can be exploited in vitro prior to transplantation. Objective: This study aimed to examine the synergistic effects of MSCs on CSC cardiomyocyte differentiation. Methods: C-kit CSCs and MSCs were isolated from 4-6 weeks C57BL/6N mice (n=9). CSC cardiomyocyte differentiation was tested after re-isolated from MSC co-culture using micron-sized particles of iron oxide, and compared to CSCs treated with MSC-conditioned medium (CdM) or without any treatment. Cardiomyocyte differentiation was detected using immunofluorescence staining and quantified using qPCR. All data were analysed by one way ANOVA. Results: More than 80% clonogenic amplified, colony-forming c-kit CSCs were at G1 phase, with a population doubling time of 17.2 ± 0.2 hr. Sox2pos GATA4dim Nkx2.5dim CSCs, when induced by dexamethasone, showed greater cardiomyocyte differentiation than the Sox2neg GATA4high Nkx2.5high CSCs after co-cultured with MSCs, as evidenced by higher cTnI, Mef2c and GATA4 expression (p<0.001). This effect was greater than CSCs treated with CdM. However, direct MSC contact did not show synergistic effects on the cardiomyocyte differentiation of Sox2neg GATA4high Nkx2.5high CSCs. Nevertheless, there was no difference in cardiomyocyte formation under growth factor directed differentiation, as evidenced by the presence of cardiac troponin I and α- sacromeric actin. Conclusion: Direct MSC-CSC interaction is needed to synergise CSC cardiomyocyte differentiation in vitro, but the benefit is confined to Sox2pos GATA4dim Nkx2.5dim CSCs only. This thesis defines the synergistic interactions between MSCs and CSCs, and support the use of two cells in combination for clinical therapy.
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Keywords
Bone marrow-derived mesenchymal stem cells