Importantly, compared with sham group, the cleaved-caspase-3 were dramatically increased at 48 h following cerebral ischemia/reperfusion injury (Supplementary Figure 1; n = 4, P < 0.05), further indicating that CypD-ERK axis involved in neuronal apoptosis at the early stage of reperfusion. Here, PPIF is linked to Cerebral ischemia.