Fang, F., Wasserman, S.M., Torres-Vazquez, J., Weinstein, B., Cao, F., Li, Z., Wilson, K.D., Yue, W., Wu, J.C., Xie, X., and Pei, X. (2014) The role of Hath6, a novel shear stress-responsive transcription factor, in endothelial differentiation and function modulation. Journal of Cell Science. 127(Pt 7):1428-40.
The key regulators of endothelial differentiation induced by shear stress (SS) are mostly unclear. Human atonal homolog 6 (Hath6) was identified as an endothelial-selective and SS-responsive transcription factor. In this study, we sought to elucidate
the role of Hath6 in the endothelial specification of embryonic stem cells. In a stepwise human embryonic stem cell-endothelial cell (hESC-EC)
induction system, Hath6 was upregulated synchronously with endothelial determination. Subsequently, gain-of-function and loss-of-function studies
of Hath6 were performed using the hESC-EC induction model and endothelial cell lines. The overexpression of Hath6, which mimics SS treatment, resulted in an increased CD45CD31+KDR+ population, a higher tubular-structure-formation capacity, and increased endothelial-specific gene expression. In contrast,
the knockdown of the Hath6 gene markedly decreased endothelial differentiation. Hath6 also facilitates the maturation of ECs in terms of endothelial gene expression, tubular structure formation, and cell migration.
We further demonstrated that eNOS is a direct target of Hath6 through a reporter system assay and western blot analysis and that the inhibition of eNOS diminishes hESC-EC differentiation. These results suggest that eNOS plays a key role in linking Hath6 to the endothelial phenotype. Further in situ hybridization studies in zebrafish and mouse embryos indicated that homologues of Hath6 are involved in vasculogenesis and angiogenesis. This study provides the first confirmation of the positive impact of Hath6 on human embryonic endothelial differentiation and function. Moreover, we present a potential signaling pathway through which
SS stimulates endothelial differentiation.