We have reported that neuron-specific conventional protein kinase C (cPKC)γ is involved in the development of cerebral hypoxic preconditioning (HPC) and the neuroprotection against ischemic injuries, but its molecular mechanism is unclear. In this study, the adult and postnatal 24 h C57BL/6J wild-type (cPKCγ) and cPKCγ knockout (cPKCγ) mice were respectively used to establish the models of middle cerebral artery occlusion (MCAO)-induced ischemic stroke in vivo and oxygen-glucose deprivation (OGD)-treated primarily cultured cortical neurons as cell ischemia in vitro. The results showed that cPKCγ knockout could increase the infarct volume and neuronal cell loss in the peri-infarct region, and enhance the neurological deficits, the impaired coordination, and the reduced muscle strength of mice following 1 h MCAO/1-7 days reperfusion. Meanwhile, cPKCγ knockout significantly increased the conversion of LC3-I to LC3-II and beclin-1 protein expression, and resulted in more reductions in P-Akt, P-mTOR, and P-S6 phosphorylation levels in the peri-infarct region of mice with ischemic stroke. The autophagy inhibitor BafA1 could enhance or reduce neuronal cell loss in the peri-infarct region of cPKCγ and cPKCγ mice after ischemic stroke. In addition, cPKCγ knockout and restoration could aggravate or alleviate OGD-induced neuronal ischemic injury in vitro through Akt-mTOR pathway-mediated autophagy. These results suggested that cPKCγ-modulated neuron-specific autophagy improves the neurological outcome of mice following ischemic stroke through the Akt-mTOR pathway, providing a potential therapeutic target for ischemic stroke.

Cell death is a key feature of neurological diseases, including stroke and neurodegenerative disorders. Studies in a variety of ischemic/hypoxic mouse models demonstrate that poly(ADP-ribose) polymerase 1 (PARP-1)-dependent cell death, also named PARthanatos, plays a pivotal role in ischemic neuronal cell death and disease progress.PARthanatos has its unique triggers, processors, and executors that convey a highly orchestrated and programmed signaling cascade. In addition to its role in gene transcription, DNA damage repair, and energy homeostasis through PARylation of its various targets, PARP-1 activation in neuron and glia attributes to brain damage following ischemia/reperfusion. Pharmacological inhibition or genetic deletion of PARP-1 reduces infarct volume, eliminates inflammation, and improves recovery of neurological functions in stroke. Here, we reviewed the role of PARP-1 and PARthanatos in stroke and their therapeutic potential.

No abstract

Galanin (GAL) plays key role in many pathophysiological processes, but its role in ischemic stroke remains unclear. Here, the models of 1 h middle cerebral artery occlusion (MCAO)/1-7 d reperfusion (R)-induced ischemic stroke and in vitro cell ischemia of 1 h oxygen-glucose deprivation (OGD)/24 h reoxygenation in primary cultured cortical neurons were used to explore GAL’s effects and its underlying mechanisms. The results showed significant increases of GAL protein levels in the peri-infarct region (P) and infarct core (I) within 48 h R of MCAO mice (p<0.001). The RT-qPCR results also demonstrated significant increases of GAL mRNA during 24-48 h R (p<0.001), and GAL receptors GalR1-2 (but not 3) mRNA levels in the P region at 24 h R of MCAO mice (p<0.001). Furthermore, the significant decrease of infarct volume (p<0.05) and improved neurological outcome (p<0.001-0.05) were observed in MCAO mice following 1 h pre- or 6 h post-treatment of GAL during 1-7 d reperfusion. GalR1 was confirmed as the receptor responsible for GAL-induced neuroprotection by using GalR2/3 agonist AR-M1896 and Lentivirus-based RNAi knockdown of GalR1. GAL treatment inhibited Caspase-3 activation through the upstream initiators Capsases-8/-12 (not Caspase-9) in both P region and OGD-treated cortical neurons. Meanwhile, GAL’s neuroprotective effect was not observed in cortical neurons from conventional protein kinase C (cPKC) γ knockout mice. These results suggested that exogenous GAL protects the brain from ischemic injury by inhibiting Capsase-8/12-initiated apoptosis, possibly mediated by GalR1 via the cPKCγ signaling pathway.