OBJECTIVETo explore the role of sonic hedgehog (Shh) pathway in regulating the proliferation, migration and differentiation of hemangioblasts derived from aorta-gonad-mesonephros (AGM).

METHODSThe hemangioblasts were isolated from AGM region of 11-day postcoitum (dpc) murine embryos by using the immuno-magnetic with CD34 and Flk1 monoclonal antibodies. The phenotypic analysis of hemangioblasts and AGM-derived stromal cells were detected by flow cytometry. The secretion of Shh was examined by immunohistochemical staining. The roles of Shh in regulating the proliferation, migration and differentiation of hemangioblasts in the transwell non-contact coculture system with AGM-derived stromal cells were observed by adding exogenous Shh N-Terminus and its antibody.

RESULTSThe protein of Shh was highly expressed on AGM-derived stromal cells. The proliferation of hemangioblasts was promoted when co-cultured with AGM-derived stromal cells, and the effects of the latter could be blocked by antibody of Shh. The proliferation of hemangioblasts was strengthened further and kept for a long time without differentiation and apoptosis when exogenous Shh N-Terminus was added into the transwell non-contact co-culture system with AGM-derived stromal cells. When exogenous Shh N-Terminus was added into the cultural supernatant of hemangioblasts without AGM-derived stromal cells, the hemangioblasts were observed to be induced to apoptosis or differentiation after a short time of proliferation. Furthermore, the ability of migration could be promoted in the co-cultured hemangioblasts by adding exogenous Shh N-Terminus.

CONCLUSIONShh pathway probably involves in the regulation of the proliferation, differentiation, apoptosis and migration of hemangioblasts, and is regulated by the AGM microenvironment.