Multiple reaction monitoring for the detection of disease-related synaptic proteins

Synaptic dysfunction occurs early in Alzheimer＇s disease （AD） and is acknowledged as a primary pathologic target for treatment. Synaptic degeneration is the pathological feature most strongly correlated with loss of cognitive function ante mortern （Terry et al., 1991）. Synapses are heavily damaged in hippocampal and neocortical regions of AD brain, whereas motor and occipital cortices are relatively spared （Honer et al., 1992）. Despite extensive work, the molecular mechanisms underlying synaptic degeneration are largely unknown.

Aquaporin 4 deficiency eliminates the beneficial effects of voluntary exercise in a mouse model of Alzheimer’s disease

Regular exercise has been shown to reduce the risk of Alzheimer’s disease(AD).Our previous study showed that the protein aquaporin 4(AQP4),which is specifically expressed on the paravascular processes of astrocytes,is necessary for glymphatic clearance of extracellular amyloid beta(Aβ)from the brain,which can delay the progression of Alzheimer’s disease.However,it is not known whether AQP4-regulated glymphatic clearance of extracellular Aβis involved in beneficial effects of exercise in AD patients.Our results showed that after 2 months of voluntary wheel exercise,APP/PS1 mice that were 3 months old at the start of the intervention exhibited a decrease in Aβburden,glial activation,perivascular AQP4 mislocalization,impaired glymphatic transport,synapse protein loss,and learning and memory defects compared with mice not subjected to the exercise intervention.In contrast,APP/PS1 mice that were 7 months old at the start of the intervention exhibited impaired AQP4 polarity and reduced glymphatic clearance of extracellular Aβ,and the above-mentioned impairments were not alleviated after the 2-month exercise intervention.Compared with age-matched APP/PS1 mice,AQP4 knockout APP/PS1 mice had more serious defects in glymphatic function,Aβplaque deposition,and cognitive impairment,which could not be alleviated after the exercise intervention.These findings suggest that AQP4-dependent glymphatic transport is the neurobiological basis for the beneficial effects of voluntary exercises that protect against the onset of AD.

Protective effects of Bushen Tiansui decoction on hippocampal synapses in a rat model of Alzheimer's disease

Bushen Tiansui decoction is composed of six traditional Chinese medicines：Herba Epimedii,Radix Polygoni multiflori,Plastrum testudinis,Fossilia Ossis Mastodi,Radix Polygalae,and Rhizoma Acorus tatarinowii.Because Bushen Tiansui decoction is effective against amyloid beta（Aβ） toxicity,we hypothesized that it would reduce hippocampal synaptic damage and improve cognitive function in Alzheimer＇s disease.To test this hypothesis,we used a previously established animal model of Alzheimer＇s disease,that is,microinjection of aggregated Aβ25–35 into the bilateral brain ventricles of Sprague-Dawley rats.We found that long-term（28 days） oral administration of Bushen Tiansui decoction（0.563,1.688,and 3.375 g/m L;4 m L/day） prevented synaptic loss in the hippocampus and increased the expression levels of synaptic proteins,including postsynaptic density protein 95,the N-methyl-D-aspartate receptor 2 B subunit,and Shank1.These results suggested that Bushen Tiansui decoction can protect synapses by maintaining the expression of these synaptic proteins.Bushen Tiansui decoction also ameliorated measures reflecting spatial learning and memory deficits that were observed in the Morris water maze（i.e.,increased the number of platform crossings and the amount of time spent in the target quadrant and decreased escape latency） following intraventricular injections of aggregated Aβ25–35 compared with those measures in untreated Aβ_（25–35）-injected rats.Overall,these results provided evidence that further studies on the prevention and treatment of dementia with this traditional Chinese medicine are warranted.

Mutant Huntingtin Causes a Selective Decrease in the Expression of Synaptic Vesicle Protein 2C

Huntington＇s disease （HD） is a neurodegenera- tive disease caused by a polyglutamine expansion in the huntingtin （Htt） protein. Mutant Htt causes synaptic transmission dysfunctions by interfering in the expression of synaptic proteins, leading to early HD symptoms. Synaptic vesicle proteins 2 （SV2s）, a family of synaptic vesicle proteins including 3 members, SV2A, SV2B, and SV2C, plays important roles in synaptic physiology. Here, we investigated whether the expression of SV2s is affected by mutant Htt in the brains of HD transgenic （TG） mice and Neuro2a mouse neuroblastoma cells （N2a cells） expressing mutant Htt. Western blot analysis showed that the protein levels of SV2A and SV2B were not signifi- cantly changed in the brains of HD TG mice expressing mutant Htt with 82 glutamine repeats. However, in the TG mouse brain there was a dramatic decrease in the protein level of SV2C, which has a restricted distribution pattern in regions particularly vulnerable in HD. Immunostaining revealed that the immunoreactivity of SV2C was progres- sively weakened in the basal ganglia and hippocampus of TG mice. RT-PCR demonstrated that the mRNA level of SV2C progressively declined in the TG mouse brain without detectable changes in the mRNA levels of SV2A and SV2B, indicating that mutant Htt selectively inhibits the transcriptional expression of SV2C. Furthermore, we found that only SV2C expression was progressively inhibited in N2a cells expressing a mutant Htt containing 120 glutamine repeats. These findings suggest that the synaptic dysfunction in HD results from the mutant Htt- mediated inhibition of SV2C transcriptional expression. These data also imply that the restricted distribution and decreased expression of SV2C contribute to the brain region-selective pathology of HD.

针刺通过调节脑可塑性相关信号缓解脑卒中肢体痉挛状态研究进展

Stroke may cause upper motor neurons lesions, and thus limb spasm may occur. Brain plasticity refers to the brain's ability to change and adapt the environment and experience when the nervous system is damaged. Acupuncture can relieve the relevant pathological status due to stroke by enhancing brain plasticity. Specifically, acupuncture may finally achieve the balance between excitatory and inhibitory neurotransmitters by inhibiting the expression of neurotransmitter GABA, neurotrophic factor BDNF and proteins related to synaptic plasticity. This article analyzed and summarized that taking advantage of nervous plasticity the acupuncture could regenerate nervous cells and restore the related regulation of the movement by upper motor neurons, so as to relieving limb spasticity. It also summarized the research and application of acupuncture in regulating related signals, providing a systematic thought for the future study on acupuncture in the treatment of stroke induced limb.

针刺通过增加前额叶皮层突触蛋白的表达对两种抑郁症动物模型的快速抗抑郁作用

Objective:To investigate the effect of acupuncture onset time and synaptic structure in two different models of depression.Methods:A total of 150 healthy male adult SPF C57BL/6J mice were divided into five time-point groups:1 h,3 h,6 h,12 h and 24 h.Each time-point group was further divided into three groups:the model,scopolamine and acupuncture groups with 10 rats each.Rats were given forced swimming stimulation(15 min,once)before the intervention.A total of 200 healthy male adult specific pathogen-free(SPF)Sprague-Dawley(SD)rats were divided into 30 normal rats,and 170 modelling ones.A total of 90 rats were successfully modeled,and were randomly divided into three time-point groups:1 h,6 h and 24 h.And each time-point group was further divided into the normal,model,scopolamine,and acupuncture group.Chronic unpredictable mild stress(CUMS)combined with individual feeding was used to establish the depressed rat model.The sucrose preference test(SPT)and open field test(OFT)were used to evaluate the success of the model.There were 10 rats in each group.The acupuncture intervention was performed once for 20 min on"Baihui(GV20)","Yintang(GV29)","Hegu(LI4)",and"Taichong(LR3)"without any other operations for the corresponding animals.Other groups were given corresponding medications.According to different time points,the forced swimming test(FST)was conducted in mice,and the FST and novelty-suppressed feeding test(NSFT)were measured in rats.Monoamine neurotransmitters(NE,DA,DOPAC,5-HT,5-HIAA,HVA)in the prefrontal cortex and hippocampus were detected with high performance liquid chromatography(HPLC).The expression of synapsin I,PSD95,p-mTOR,mTOR,and BDNF in the prefrontal cortex and hippocampus was determined by western blot.Results:At the 1 h time point,compared with the model group,the immobility time was significantly decreased in the acupuncture group(P<0.05).At 3 h,6 h,12 h,and 24 h,compared with the model group,the immobility time was significantly reduced in both scopolamine and acupuncture groups(P<0.05).At the 1 h time point,compared with the normal group,the immobility time of FST and the latency to feed were significantly increased in the model group(P<0.05).Compared with the model group,the immobility time of FST showed a significant reduction in the acupuncture group(P<0.05).At the 6h and 24 h time points,compared with the normal group,the immobility time of FST and the latency to feed were significantly increased in the model group(P<0.05).Compared with the model group,the immobility time of FST was significantly decreased in the scopolamine and acupuncture groups(P<0.05).At the 1 h and 24 h time points,compared with the normal group,the expression levels of 5-HT,5-HIAA,NE,DA,DOPAC,and HVA of the prefrontal cortical and hippocampal tissues were significantly reduced in the model group(P<0.05).At the 1 h and 24 h time points,compared with the model group,the expression levels of synapsin I,PSD95,p-mTOR,and BDNF of the prefrontal cortex were significantly increased in the acupuncture group(P<0.05).At the 1 h and 24 h time points,compared with the normal group,the expression levels of synapsin I,PSD95,p-mTOR,and BDNF of the prefrontal cortex were significantly reduced in the model group(P<0.05).Compared with the model group,the expression levels of synapsin I,PSD95,p-mTOR,and BDNF of the prefrontal cortex were significantly increased in the acupuncture group(P<0.05).At the 1 h and 24 h time points,compared with the normal group,the expression levels of synapsin I,PSD95,p-mTOR,and BDNF of the hippocampal tissues were significantly reduced in the model group(P<0.05).Compared with the model group,the expression levels of synapsin I,PSD95,p-mTOR,and BDNF of the hippocampus were not significantly different in the acupuncture group(P>0.05).Conclusion:Acupuncture may play a rapid antidepressant effect by increasing the expression of synaptic plasticity proteins in the prefrontal cortex.