This Article Full Text Full Text (PDF) Data Supplement All Versions of this Article: 29/5/718    most recent ATVBAHA.109.184200v1 Submit a response Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Permissions Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Kelly, M. A. Articles by Hirschi, K. K. Search for Related Content PubMed PubMed Citation Articles by Kelly, M. A. Articles by Hirschi, K. K.

(Arteriosclerosis, Thrombosis, and Vascular Biology. 2009;29:718.)
© 2009 American Heart Association, Inc.

Cell Biology/Signaling

Signaling Hierarchy Regulating Human Endothelial Cell Development

Melissa A. Kelly; Karen K. Hirschi

From the Center for Cell and Gene Therapy (M.A.K., K.K.H.), Children’s Nutrition Research Center (K.K.H.), the Department of Molecular and Cellular Biology (M.A.K., K.K.H.), and the Department of Pediatrics (K.K.H.), Baylor College of Medicine, Houston, Tex.

Correspondence to Karen K. Hirschi, Baylor College of Medicine, One Baylor Plaza N1020, Houston, TX 77030. E-mail khirschi{at}bcm.edu

Objective— Our present knowledge of the regulation of mammalian endothelial cell differentiation has been largely derived from studies of mouse embryonic development. However, unique mechanisms and hierarchy of signals that govern human endothelial cell development are unknown and, thus, explored in these studies.

Methods and Results— Using human embryonic stem cells as a model system, we were able to reproducibly and robustly generate differentiated endothelial cells via coculture on OP9 marrow stromal cells. We found that, in contrast to studies in the mouse, bFGF and VEGF had no specific effects on the initiation of human vasculogenesis. However, exogenous Ihh promoted endothelial cell differentiation, as evidenced by increased production of cells with cobblestone morphology that coexpress multiple endothelial-specific genes and proteins, form lumens, and exhibit DiI-AcLDL uptake. Inhibition of BMP signaling using Noggin or BMP4, specifically, using neutralizing antibodies suppressed endothelial cell formation; whereas, addition of rhBMP4 to cells treated with the hedgehog inhibitor cyclopamine rescued endothelial cell development.

Conclusions— Our studies revealed that Ihh promoted human endothelial cell differentiation from pluripotent hES cells via BMP signaling, providing novel insights applicable to modulating human endothelial cell formation and vascular regeneration for human clinical therapies.

The signaling hierarchy that regulates human endothelial cell differentiation is currently unknown. Our studies revealed that Ihh promoted endothelial cell differentiation from pluripotent human embryonic stem cells via BMP signaling, providing novel insights applicable to modulating human endothelial cell formation and vascular regeneration for human clinical therapies.

Key Words: human embryonic stem cells • endothelial cells • Indian hedgehog • BMP signaling • vascular development