title: Uniaxial cyclic stretch stimulates TRPV4 to induce realignment of human embryonic stem cell-derived cardiomyocytes.
abstract: Human pluripotent stem cell-derived cardiomyocytes (hPSC-CMs) in culture are randomly organized and do not typically show directional alignment. In the present study, we used uniaxial cyclic stretch to facilitate the alignment of cultured human embryonic stem cell-derived cardiomyocytes (hESC-CMs), so that these cells can be more adult-like for potential future application in drug screening and in vitro studies of cardiac function. We then explored the functional role of mechanosensitive TRPV4 channels in cyclic stretch-induced realignment of hESC-CMs. RT-PCR, immunoblots and immunostaining detected TRPV4 expression in these cells. 4α-phorbol 12,13-didecanoate (4α-PDD), a TRPV4 agonist, elicited a cytosolic Ca(2+) ([Ca(2+)]i) rise, the effect of which was abolished by TRPV4 inhibitors RN1734 and HC067047, and a TRPV4 dominant negative construct. These results confirmed the functional presence of TRPV4 in these cells. Importantly, longitudinal stretch was found to induce a [Ca(2+)]i rise, the effect of which was inhibited by TRPV4 antagonists. Furthermore, uniaxial cyclic stretch for 2h induced realignment of hESC-CMs in the direction transverse to the direction of stretch, the effect of which was also abolished by TRPV4 antagonists. Akt phosphorylation was found to be a downstream signal of TRPV4. Taken together, these data strongly suggest endogenous TRPV4 channels as a mechanosensor, mediating cyclic stretch-induced realignment of hESC-CMs.
authors.affiliation: School of Biomedical Sciences and Li Ka Shing Institute of Health Science, The Chinese University of Hong Kong, Hong Kong, China; Shenzhen Research Institute, The Chinese University of Hong Kong, Shenzhen, China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Qi
authors.affiliation: School of Biomedical Sciences and Li Ka Shing Institute of Health Science, The Chinese University of Hong Kong, Hong Kong, China; Shenzhen Research Institute, The Chinese University of Hong Kong, Shenzhen, China.
authors.forename: Zhichao
authors.initials: Z
authors.lastname: Li
authors.affiliation: Stem Cell and Regenerative Medicine Consortium, The University of Hong Kong, Hong Kong, China.
authors.forename: Chi-Wing
authors.initials: CW
authors.lastname: Kong
authors.affiliation: Department of Chemical Pathology, The Chinese University of Hong Kong, Hong Kong, China.
authors.forename: Nelson L
authors.initials: NL
authors.lastname: Tang
authors.affiliation: School of Biomedical Sciences and Li Ka Shing Institute of Health Science, The Chinese University of Hong Kong, Hong Kong, China.
authors.forename: Yu
authors.initials: Y
authors.lastname: Huang
authors.affiliation: Stem Cell and Regenerative Medicine Consortium, The University of Hong Kong, Hong Kong, China.
authors.forename: Ronald A
authors.initials: RA
authors.lastname: Li
authors.affiliation: School of Biomedical Sciences and Li Ka Shing Institute of Health Science, The Chinese University of Hong Kong, Hong Kong, China; Shenzhen Research Institute, The Chinese University of Hong Kong, Shenzhen, China. Electronic address: yao2068@cuhk.edu.hk.
authors.forename: Xiaoqiang
authors.initials: X
authors.lastname: Yao
mesh_terms: D000328:Adult; D000818:Animals; D020013:Calcium Signaling / Q000235:genetics; D002454:Cell Differentiation / Q000235:genetics*; D002460:Cell Line; D000066449:Human Embryonic Stem Cells / Q000166:cytology / Q000378:metabolism*; D006801:Humans; D032383:Myocytes, Cardiac / Q000166:cytology / Q000378:metabolism*; D013314:Stress, Mechanical; D050916:TRPV Cation Channels / Q000096:biosynthesis* / Q000235:genetics
chemical_list: D050916:TRPV Cation Channels; C416986:TRPV4 protein, human
keywords: Cardiomyocyte alignment; Human embryonic stem cells; PI3K-Akt signaling pathway; TRPV4 channel