α-Syn is known as a potent chemoattractant for immune cells, including microglia in chronic neurodegenerative disorders.27,28 Similarly the ischemic vascular endothelium of C57BL/6J mice expresses ICAM-1 and MMP-9, facilitating the recruitment and transmigration of peripheral immune cells into the injured brain.29 MMP-9 is released by ischemic cells including microglia22 and mediates degradation of basement membranes and tight junction components in the early phase of ischemic stroke,30 thereby facilitating peripheral immune cell entry, which in turn exacerbates the ischemic damage. The gene discussed is MMP9; the disease is ischemic stroke.