PECAM1 and Stroke: Optogenetic stimulation of GFAP-Arch mice led to not only a reduction in glial scar stiffness but also the increases of EdU+DCX+ and EdU+CD31+ cells, which indicated an increased capacity to promote endogenous neuro-regeneration and angiogenesis for neurological recovery after stroke (Figure 6A-B and Figure S9B-C).