CXCR2 and Its Related Ligands Play a Novel Role in Supporting the Pluripotency and Proliferation of Human Pluripotent Stem Cells

Basic fibroblast growth factor (bFGF) is a crucial factor sustaining human pluripotent stem cells (hPSCs). We designed this study to search the substitutive factors other than bFGF for the maintenance of hPSCs by using human placenta-derived conditioned medium without exogenous bFGF (hPCCM−), containing chemokine (C-X-C motif) receptor 2 (CXCR2) ligands, including interleukin (IL)-8 and growth-related oncogene α (GROα), which were developed on the basis of our previous studies. First, we confirmed that IL-8 and/or GROα play independent roles to preserve the phenotype of hPSCs. Then, we tried CXCR2 blockage of hPSCs in hPCCM− and verified the significant decrease of pluripotency-associated genes expression and the proliferation of hPSCs. Interestingly, CXCR2 suppression of hPSCs in mTeSR™1 containing exogenous bFGF decreased the proliferation of hPSCs while maintaining pluripotency characteristics. Lastly, we found that hPSCs proliferated robustly for more than 35 passages in hPCCM− on a gelatin substratum...