The Effects And Mechanisms Of Cdh1-APC In Ischemic Neuronal Apoptosis

OBJECTIVE To investigate the expression changes of Cdhl-APC in hippocampus after global cerebral ischemia in rat.METHODS24adult male SD rats were allocated into3groups:control group, ischemia+reperfusion1day group and ischemia+reperfusion3day group. Global cerebral ischemia was induced by4-vessel occlusion method of Pulsinelli. Control rats were subjected to shame surgery. On the1,3day of reperfusion following ischemia, the rat was executed under anesthesia and the hippocampus was removed for the following analysis. TUNEL method was used for testing neuronal apoptosis after ischemia. The expressions of Cdhl and the downstream substrates of Cdhl-APC (such as SnoN and Skp2) were measured by Western blot.RESLUTS Compared with control group, the expression of Cdhl in hippocampus was significantly decreased on1and3days after reperfusion in ischemia group (P<0.05), while a large amount of apoptotic neurons were found in hippocampal CA1region and the two downstream substrates of Cdhl-APC (SnoN and Skp2) were significantly increased after global cerebral ischemia injury (P<0.05).CONCLUSION The activity of Cdhl-APC in hippocampus is down-regulated after global cerebral ischemia injury, which suggests that the down-regulation of Cdhl-APC may be involved in neuronal apoptosis following ischemic brain injury. This study also brings a prospect to explore the function of Cdhl-APC in the injured central nervous system. OBJECTIVE To investigate Cdhl-APC’s effect on the maintenance of neuronal glucose metabolic balance; to observe the change of glucose metabolism after neuronal ischemic damage and explore the effects of Cdhl lenti-virus on neuronal glucose comsumption and apoptosis.METHODS Primary rat cortical neurons were allocated into control group, OGD/R group, OGD/R plus Cdhl lenti-virus group and OGD/R plus Cdhl control lenti-virus group. OGD/R model was performed in neurons, Cdhl control and overexpressing lenti-virus was constructed by gene recombinant techniques. The expressions of Cdhl and the downstream substrates of Cdhl-APC (such as SnoN and Skp2) in each group were measured by Western blot, as well as the glycolysis and PPP key enzyme (Pfkfb3and G6PD). TUNEL method was used for testing neuronal apoptosis after ischemia with or without lenti-virus infection.RESULTS Western-blot results indicated that Cdhl expression was significantly reduced after OGD/R, while its downstream substrates (SnoN and Skp2) were significantly increased, compared with control group (P<0.05). The fusion protein of Cdhl-GFP was detected in neurons after infection with Cdhl lenti-virus and there’s no fusion protein detected in neurons infected with control lenti-virus. The glycolysis key enzyme Pfkfb3expression was not detected in the neurons of control group, however, Pfkfb3was expressed in both OGD/R and OGD/R plus Cdhl control lenti-virus group, the effect of which was significantly prevented in OGD/R plus Cdhl lenti-virus group (P<0.05). Compared with the control group, the PPP key enzyme G6PD was significantly decreased in both OGD/R and OGD/R plus Cdhl control lenti-virus group (P<0.05), and the decrease was significantly inhibited in OGD/R plus Cdhl lenti-virus group. Moreover, neuronal apoptosis was significantly reduced in OGD/R plus Cdhl lenti-virus group, compared with the OGD/R and OGD/R plus Cdhl control lenti-virus group (P<0.05).CONCLUSION Our study indicated that the neuronal glucose metabolism was imbalanced after OGD damage, glycolysis was activated while PPP was inhibited, the effect of which was involved in ischemic neuronal apoptosis. Using Cdhl lenti-virus that up-regulated Cdhl activity and subsequently ubiquitinly degraded Pfkfb3can keep the balance of glucose metabolism of neurons and reduce neuronal apoptosis after OGD.