A Novel CXCR4 Antagonist CX549 Induces Neuroprotection in Stroke Brain.

C-X-C chemokine receptor type 4 (CXCR4) is a receptor for a pleiotropic chemokine CXCL12. Previous studies have shown that the acute administration of the CXCR4 antagonist AMD3100 reduced neuroinflammation in stroke brain and mobilized bone marrow hematopoietic stem cells (HSCs). The purpose of this study was to characterize the neuroprotective and neurotrophic effect of a novel CXCR4 antagonist CX549. We demonstrated that CX549 had a higher affinity for CXCR4 and was more potent than AMD3100 to inhibit CXCL12-mediated chemotaxis in culture. CX549 effectively reduced the activation of microglia and improved neuronal survival after injury in neuron/microglia cocultures. Early poststroke treatment with CX549 significantly improved behavioral function, reduced brain infarction, and suppressed the expression of inflammatory markers. Compared to AMD3100, CX549 has a higher affinity for CXCR4, is more efficient to mobilize HSCs for transplantation, and induces behavioral improvement. Our data support that CX549 is a potent anti-inflammatory agent, is neuroprotective against ischemic brain injury, and may have clinical implications for the treatment of stroke.