[Expression of metabotropic glutamate receptor 4 in cardiomyocytes differentiated from mouse embryonic stem cells in vitro].

Objective: To investigate the expression of metabotropic glutamate receptor 4 (mGluR4) in cardiomyocytes differentiated from mouse embryonic stem cells (ES cells).

Methods: ES cells were differentiated into cardiomyocytes with hanging-drop cultures. Retinoic acid (RA) and dimethyl sulfoxide (DMSO) were used as positive and negative controls, respectively. The co-expression of cardiac sarcomeric protein (α-actinin or troponin-T) and mGluR4 were verified by immunocytochemistry and flow cytometry analysis. The mRNA and protein expressions of mGluR4 were verified by RT-PCR and Western blot analysis, respectively. Meanwhile, the expression of mGluR4 in prenatal mouse heart was also examined.

Results: mGluR4 was expressed in both mouse ES cells and ES cell-derived cardiomyocytes. The level of mGluR4 protein expression decreased during the maturation of the cardiomyocytes. The co-expression rate of mGluR4 and Troponin T in the beating embryoid bodies (EBs) was only (3.00 ±1.00)%. On the other hand, mGluR4 gene and protein expressions showed remarkable down-regulation in the development of mouse fetal heart, which was not detected in mouse adult heart.

Conclusion: The expression of mGluR4 is down-regulated in the cardiomyocyte differentiation of ES cells. The trend of expression is consistent with that in the prenatal mouse heart development.