The Effect of CXCL12 on Endothelial Progenitor Cells: Potential Target for Angiogenesis in Intracerebral Hemorrhage

Endothelial progenitor cells (EPCs) may contribute to vascular repair and angiogenesis. Chemokine (C-X-C motif) ligand 12 (CXCL12/SDF-1) is known to play an important role in the mobilization and recruitment of progenitor cells. Therefore, we assessed the function of CXCL12 as a stimulating molecule of angiogenesis in EPCs and the underlying mechanism after intracerebral hemorrhage (ICH). Isolated EPCs from male Sprague-Dawley rats, stimulate with various doses of CXCL12. Then, 3-(4,5-Dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay was used to assess the proliferation of EPCs, and cell migration and adhesion were analyzed by transwell chamber assay. Furthermore, mRNA levels of endothelial markers von Willebrand Factor (vWF), Tie-2, and vascular endothelial cadherin (VE-cadherin) were explored by real-time polymerase chain reaction. Capillary tube and vessel formation in vitro and in vivo were detected after pretreatment with the C-X-C chemokine receptor type 4 (CXCR4) inhibitor AMD3100. Following stimulation with various doses of CXCL12, an obvious dose-dependent increase in the proliferation, migration, and adhesion of EPCs was confirmed. Furthermore, the mRNA levels of endothelial markers vWF, Tie-2, and VE-cadherin were also demonstrated in CXCL12-treated EPCs, indicating that CXCL12 could regulate EPC differentiation to endothelial cells. Importantly, these increases depended on the activation of CXCR4 signaling, as pretreatment with CXCR4 inhibitor AMD3100 dramatically dampened the CXCL12-induced effects. Additionally, blocking CXCR4 signaling dampened CXCL12-induced angiogenic activity both in vitro and in vivo. Following construction of a rodent ICH model, scaffolds delivering CXCL12 together with EPCs resulted in an evident increase in blood vessel formation; however, this increase in blood vessels was attenuated with delivery of AMD3100. CXCL12 stimulates EPCs to induce angiogenesis though the CXCR4 pathway after ICH. Consequently, our findings provide a potential target for angiogenesis in ICH.