PECAM1.sup.+/Sca1.sup.+/CD38.sup.+ Vascular Cells Transform into Myofibroblast-Like Cells in Skin Wound Repair

Skin injury induces the formation of new blood vessels by activating the vasculature in order to restore tissue homeostasis. Vascular cells may also differentiate into matrix-secreting contractile myofibroblasts to promote wound closure. Here, we characterize a PECAM1.sup.+ /Sca1.sup.+ vascular cell population in mouse skin, which is highly enriched in wounds at the peak of neoangiogenesis and myofibroblast formation. These cells express endothelial and perivascular markers and present the receptor CD38 on their surface. PECAM1.sup.+ /Sca1.sup.+ /CD38.sup.+ cells proliferate upon wounding and could give rise to [alpha]-SMA.sup.+ myofibroblast-like cells. CD38 stimulation in immunodeficient mice reduced the wound size at the peak of neoangiogenesis and myofibroblast formation. In humans a corresponding cell population was identified, which was enriched in sprouting vessels of basal cell carcinoma biopsies. The results indicate that PECAM1.sup.+ /Sca1.sup.+ /CD38.sup.+ vascular cells could proliferate and differentiate into myofibroblast-like cells in wound repair. Moreover, CD38 signaling modulates PECAM1.sup.+ /Sca1.sup.+ /CD38.sup.+ cell activation in the healing process implying CD38 as a target for anti-angiogenic therapies in human basal cell carcinoma.