PCSK1 and brain ischemia: Compared with that in the ipsilateral striatum of NC shRNA lentivirus-injected mice, the amount of PI+ cells were significantly increased in the ischemic striatum of TRAF2 shRNA lentivirus-injected mice (Fig. 6a, b), whereas administration of nec-1 remarkably abolished cerebral ischemia-induced cell death, both in control and TRAF2 knockdown mice.