Effects Of Apolipoprotein E Mimetic Peptide COG1410 On Central Autophagy And Apoptosis After Subarachnoid Hemorrhage

objective: COG1410,an modified apolipoprotein E(apoE)mimetic peptide derived from the apolipoprotein E(apo E)receptor binding region,was adopted in this study to research the effect as well the potential mechanism on the autophagy and apoptosis in early brain injury(EBI)after experimental subarachnoid hemorrhage(SAH).Methods: We perforated SAH model by endovascular puncture.Firstly,the changes in autophagy markers(LC3 and Beclin-1)levels,apoptosis marker Cleaved-Caspase-3(c-Caspase-3)levels and the signal protein phosphorylated glycogen synthase kinase-3 beta(p-GSK-3?)levels were measured by Western blot,in the 6 hours,24 hours,48 hours and 72 hours after experimental SAH.Then,COG1410 was administrated at the time point of relatively highest autophagic level.The neurological change and the grade of subarachnoid hemorrhage in sham group,SAH group,SAH + Saline group,and SAH + COG1410 group,were evaluated by Garcia score and SAH grading system,respectively.The levels of LC3 and Beclin-1,c-Caspase-3 and p-GSK-3? were measured by Western blot,and the expression of c-Caspase-3 in cortical neurons was labeled by immunofluorescence staining.Finally,the inhibitor LY294002(LY)and agonist Okadaic acid(OA)of GSK-3? were administrated through the lateral ventricle puncture,to achieve the upregulation and down-regulation of p-GSK-3?,respectively.then we recored the autophagy in the model brain and neurons after COG1410 administration by western blot and immunofluorescence staining,in the groups of SAH+Saline,SAH+COG1410,SAH+COG1410+DMSO,SAH+COG1410+LY and SAH+COG1410+OA.Results:(1)Compared with the sham group,the level of autophagy in the injured cerebral hemisphere was increased at 6 hours after SAH(P<0.05),peaked at 24 hours after SAH(P<0.01),then decreased gradually,and the levelof p-GSK-3? had a same trend;With the administration of COG1410 24 hours after SAH,the brain autophagic levels was further promoted(P<0.05).(2)The apoptosis level was not completely synchronized with the changes of autophagy and p-GSK-3? level,weakened but remained a relatively high level in the later phase of EBI;After administrating COG1410 by,the apoptotic levels in the injured hemisphere and the cortical neurons were downregulated(P<0.05).(3)The neurological score in the model group(11.17±1.83)was significantly decreased(P<0.01),compared to the sham operated group(16.50±1.05),but the decreased score had a notable improvement with the administration of COG1410,with an improved score(15.17±0.75),and the statistical difference is significant(P<0.01).However,the administration of COG1410 showed no obvious effect to the SAH score.(4)In addition,COG1410-promoted autophagy was further enhanced by the phosphorylation of glycogenase kinase 3beta,but down-regulated by the dephosphorylation of glycogenase kinase 3beta.Conclusion: COG1410 may enhance the brain autophagy during EBI after SAH by the phosphorylation of GSK-3?,thus attenuate neuronal apoptosis and improve the neurological function of the models,COG1410-promoted autophagy is also a promising target for future study of the treatment for EBI after SAH.