Effects of esketamine on depression-like behavior and dendritic spine plasticity in the prefrontal cortex neurons of spared nerve injury-induced depressed mice

The present study utilized the spared nerve injury (SNI) to create a mouse model of depression to investigate the impact of esketamine on depressive-like behaviors, on the expression of PSD-95 and CRMP2 proteins, and on changes in neuronal dendritic spine plasticity in the prefrontal cortex (PFC). Depressive-like behavioral tests were performed 1 h after esketamine treatment, and the PFC tissues were obtained on the fourth day after completing the behavioral tests. Then, dendritic spine density and morphology in the PFC were measured using Golgi staining, and CRMP2 and PSD-95 proteins were obtained from PFC tissue by western blotting. The results of this study showed that esketamine significantly increased the immobility time in the forced swimming test and tail suspension test. In the open field test, esketamine increased the time spent in the open arms, the time spent in the central area, and the total distance covered. It also increased the protein expression levels of CRMP2 and PSD-95 in addition to the total and mature dendritic spine density of the PFC in SNI-depressed mice. Esketamine can significantly improve depression-like behaviors in SNI-depressed mice and promote an increase in dendritic spine density and maturation in the PFC. These effects may be associated with changes in CRMP2 and PSD-95 expression.

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.