Evaluation of Toll Like Receptors Expression in Cardiomyocyte Differentiation from Human Embryonic Stem Cells.

Objective: The transmembrane receptor family of Tolllike receptors (TLRs) is expressed in immune cells and cardiac muscle. To date, several TLRs (numbered 1-11) have been identified in humans. TLRs may play a role in initiating early inflammatory and functional responses to danger signals arising from ischemia-reperfusion and inflammatory stimuli. Human embryonic stem cells (hESCs) have the potential to provide an unlimited source of cardiomyocytes, which are invaluable resources for drug or toxicology screening, medical research, and cell therapy. Materials and Methods: Royan H5 and Royan H6 hESC lines were used in this study. Suspension culture of hESCs was performed according to a recently published protocol. Differentiation of the cells into cardiomyocytes in suspension was performed according to the Laflamme et al. protocol with some modifications. In this study, expression of TLR2, TLR3, TLR4, TLR5 and TLR9 was evaluated by RT-PCR and Q-PCR during cardiomyocyte differentiation on day 8, 14 and 25 (mature cardiomyocyte). Results: According to Q-PCR data, TLR9 expression has increased and TLR5 expression has decreased in linear pattern during cardiomyocyte differentiation. Expression pattern of TLR2 and TLR4 was same in sigmoid shape. In both of them, expression level was lowest in mature cardiomyosyte. Also, about TLR3 expression, our data was shown sigmoid shape but the lowest expression related to 8th day after differentiation. Conclusion: The goal of this study was to investigate the ability TLR expression in cardiomyocyte differentiation from human embryonic stem cells. According to results, all of TLRs in this study have been expressed in cardiomyocyte in variable level. TLRs expression related to inflammatory responses, ischemia and contractility. On the other hand, myocardial infarction and all of myocardial ischemia diseases have inflammatory reasons. Hence, evaluation of TLRs expression during cardiomyocyte differentiation is indispensable in cardiac cell based therapy. [ABSTRACT FROM AUTHOR]