Salidroside regulates Akt/GSK-3β/CRMP-2expression and axonal regeneration in MCAO rats / 中国药理学通报

Aim To investigate the axonal regeneration effect of salidroside in MCAO rats and its potential mechanism.Methods Thirty-six healthy adult male Sprague-Dawley rats were randomly divided into three groups: sham, MCAO, MCAO+Sal groups.The rats were subjected to focal cerebral ischemia/reperfusion with suture-occluded method.Neurological deficit testing was performed with Zea Longa scale.The protein expression of p-Akt(Ser473), Akt, p-GSK-3β(Ser9), GSK-3β, p-CRMP-2(Thr514) and CRMP-2 in side cerebral ischemic tissues were determined using Western blot analysis.NF200 immunofluorescence staining was used to evaluate axonal regeneration.Results Compared with MCAO group,salidroside significantly improved the neurological deficit,up-regulated the protein expression of NF200,p-Akt and p-GSK-3β,and inhibited the protein expression of p-CRMP-2.Conclusions Salidroside improves neurological function recovery after focal cerebral/ischemic injury in rats,which may be associated with the up-regulation of phosphorylated Akt and GSK-3β and inhibition of phosphorylated CRMP-2,thereby promoting axonal regeneration.

CRMP2 alleviates neurological deficit by reducing neuron apoptosis in rats after cerebral ischemia/reperfusion injury / 中国药理学通报

Aim To investigate the influence of the overexpression of CRMP2 on neural cell apoptosis after ischemia reperfusion injury in rats and its possible mechanism. Methods A total of 192 male adult SD rats were divided into four groups: sham group, cere-bral ischemia/reperfusion group( MCAO group) , cere-bral ischemia with blank plasmid control group( MCAO+GFP group ) , cerebral ischemia with CRMP2 eu-karyotic plasmid group ( MCAO + CRMP2/GFP group) . One day after injecting eukaryotic plasmid, the rats were operated for 120-min ischemia through MCA occlusion and reperfused. At 48 h and 1 wk, the expression of CRMP2 , p53 , Caspase-3 , Caspase-8 and BCL2 in brain tissue was tested by RT-PCR and West-ern blot. Apoptotic cells were observed by TUNEL test. TTC staining was use to detect cerebral infarction volume. The neural function of the rats were also eval-uated. Results Compared with the sham group, the expression levels of CRMP2 and BCL2 in MCAO group and MCAO +GFP group were significantly decreased ( P <0. 01 ) , while p53 , Caspase-3 , Caspase-8 and TUNEL positive cells were elevated(P<0. 01). Inter-vention of CRMP2 eukaryotic plasmid resulted in the increased expression of CRMP2 and BCL2 ( P<0. 01 ) and the decreased p53 , Caspase-3 and Caspase-8 ex-pression. In TUNEL test, overexpression of CRMP2 obviously decreased the number of TUNEL positive cells(P<0. 01). The expression of BDNF was upregu-lated after cerebral ischemic injury ( P<0. 01 ) , while overexpression of CRMP2 increased BDNF more signif-icantly ( P <0. 01 ) . TTC staining showed cerebral in-farction Volume of MCAO + CRMP2/GFP group was obviously decreased ( P <0. 01 ) , and neurologic defi-cits were significantly improved ( P <0. 01 ) . Conclu-sion The overexpression of CRMP2 reduces nerve cell apoptosis possibly by regulating the mitochondrial ap-optosis pathway after cerebral ischemia/reperfusion in-jury to protect nervous system.

Ferulic acid regulates the AKT/GSK-3beta/CRMP-2 signaling pathway in a middle cerebral artery occlusion animal model / 한국실험동물학회지

Ferulic acid, a component of the plants Angelica sinensis (Oliv.) Diels and Ligusticum chuanxiong Hort, exerts a neuroprotective effect by regulating various signaling pathways. This study showed that ferulic acid treatment prevents the injury-induced increase of collapsin response mediator protein 2 (CRMP-2) in focal cerebral ischemia. Glycogen synthase kinase-3beta (GSK-3beta) regulates CRMP-2 function through phosphorylation of CRMP-2. Moreover, the pro-apoptotic activity of GSK-3beta is inactivated by phosphorylation by Akt. This study investigated whether ferulic acid modulates the expression of CRMP-2 and its upstream targets, Akt and GSK-3beta, in focal cerebral ischemia. Male rats were treated immediately with ferulic acid (100 mg/kg, i.v.) or vehicle after middle cerebral artery occlusion (MCAO), and then cerebral cortices were collected 24 hr after MCAO. MCAO resulted in decreased levels of phospho-Akt and phospho-GSK-3beta, while ferulic acid treatment prevented the decrease in the levels of these proteins. Moreover, phospho-CRMP-2 and CRMP-2 levels increased during MCAO, whereas ferulic acid attenuated these injury-induced increases. These results demonstrate that ferulic acid regulates the Akt/GSK-3beta/CRMP-2 signaling pathway in focal cerebral ischemic injury, thereby protecting against brain injury.

CRMP-2 is involved in hypoxic preconditioning-induced neuroprotection against cerebral ischemic injuries of mice / 基础医学与临床

Objective To investigate whether conventional protein kinase C (cPKC ) βⅡ-interacting collapsin response mediator protein-2 (CRMP-2) provides neuroprotection against cerebral ischemic (I) injuries. Methods Male BALB/c mice were randomly divided into normoxic control (Nor) , HPC, Nor + Sham, HPC + Sham, Nor + I and HPC + I groups (n = 6 per group). Using our HPC and MCAO mouse models, we applied immunoprecipita-tion, two-dimensional electrophoresis and mass spectrometry to characterize cPKCβⅡ-interacting proteins and combined with SDS-PAGE and Western blot to quantitatively analyze CRMP-2 phosphorylation and degradation levels in the brain of mice after HPC and MCAO. Results The expression level of 10 cPKCβⅡ-interacting proteins changed obviously in cerebral cortex of HPC mice when compared with Nor group. One of these proteins, CRMP-2 protein level increased in particulate fraction and decreased in cytosolic fraction of cerebral cortex of HPC mice. CRMP-2 phosphorylation level in ischemic core (Ic) of cerebral cortex decreased significantly ( P < 0. 05 , n = 6) as compared with that of Nor + sham group, but CRMP-2 phosphorylation level in HPC +I group increased significantly as compared with that of Nor +I group ( P < 0. 05, n = 6). In ischemic cortex, CRMP-2 degradation (proteolysis) was observed as the appearance of 55 ku breakdown products (BDP). However, the CRMP-2 degradation level, BDPs products decreased significantly in penumbra ( P) of ischemic cortex from HPC +I group when we compared with that of Nor +I group (P < 0. 05, n = 6 ). Conclusion CRMP-2 is involved in attenuating the decrease of CRMP-2 phosphorylation in ischemic core and in inhibiting its degradation in penumbra of cerebral cortex of mice thereby to lessen the ischemic injuries.