Sonic Hedgehog signaling regulates vascular differentiation and function in human CD34 positive cells: vasculogenic CD34(+) cells with Sonic Hedgehog.

Identification of pivotal factors potentially present in the in situ environment and capable of influencing the function of CD34+ cells, which can be used for autologous cell therapy, is of paramount interest. SHh is one of the morphogens essential for embryonic vascular development as well as postnatal neovascularization, and the activation of SHh signaling with angiogenic and vascular differentiation responses in CD34+ cells by SHh treatment differed depending on the G-CSF treatment or the background disease. SHh enhanced the migration, proliferation, adhesion, and EPC colony forming capacities of G-CSF mobilized CD34+ cells, increasing the vasculogenic/angiogenic potential for neovascularization. An increase in the differentiation potential of CD34+ cells toward vascular lineages was demonstrated with SHh treatment involving TGFβ signaling pathway. The SHh-activated G-CSF mobilized CD34+ cells directly contributed to vascular regeneration while non-activated CD34+ cells showed a lower regenerative capacity in a mouse ischemic hindlimb model. SHh signaling regulates human CD34+ cell fate and function, and may potentiate the therapeutic effect of G-CSF mobilized CD34+ cells on ischemic diseases.