Downregulation of caveolin-1 contributes to the synaptic plasticity deficit in the hippocampus of aged rats

Caveolin-1 is involved in the regulation of synaptic plasticity, but the relationship between its ex-pression and cognitive function during aging remains controversial. To explore the relationship be-tween synaptic plasticity in the aging process and changes in learning and memory, we examined caveolin-1 expression in the hippocampus, cortex and cerebellum of rats at different ages. We also examined the relationship between the expression of caveolin-1 and synaptophysin, a marker of synaptic plasticity. Hippocampal caveolin-1 and synaptophysin expression in aged （22-24 month old） rats was significantly lower than that in young （1 month old） and adult （4 months old） rats. Ex- pression levels of both proteins were significantly greater in the cortex of aged rats than in that of young or adult rats, and levels were similar between the three age groups in the cerebellum. Linear regression analysis revealed that hippocampal expression of synaptophysin was associated with memory and learning abilities. Moreover, synaptophysin expression correlated positively with caveolin-1 expression in the hippocampus, cortex and cerebellum. These results confirm that caveolin-1 has a regulatory effect on synaptic plasticity, and suggest that the downregulation of hippocampal caveolin-1 expression causes a decrease in synaptic plasticity during physiological aging.

Effects of sericin on heme oxygenase-1 expression in the hippocampus and cerebral cortex of type 2 diabetes mellitus rats

Previous studies have demonstrated that sericin effectively reduces blood glucose, and protects islet cells, as well as the gonads and kidneys. However, whether sericin improves diabetes mellitus-induced structural and functional problems in the central nervous system remains poorly understood. Rat models of type 2 diabetes mellitus were established by intraperitoneal injection of streptozotocin. The present study observed histological changes in the hippocampus and cerebral cortex, as well as heme oxygenase-1 expression, and explored sericin effects on the central nervous system in diabetic rats. Pathological damage to neural cells in the rat hippocampus and cerebral cortex was relieved following intragastric administration of sericin at a dose of 2.4 g/kg for 35 consecutive days. Heme oxygenase-1 protein and mRNA expressions were decreased in the hippocampus and cerebral cortex of diabetes mellitus rats after sericin treatment. The results suggest that sericin plays a protective effect on the nervous system by decreasing the high expression of heme oxygenase-1 following diabetes mellitus.

Endothelin-1-induced mini-stroke in the dorsal hippocampus or lateral amygdala results in deficits in learning and memory

Functional and structural alterations in brain connectivity associated with brain ischemia have been extensively studied. However, the mechanism whereby local ischemia in deep brain region affect brain functions is still unknown. Here, we first established a mini-stroke model by infusion of endothelin-1 （ET-1） into the dorsal hippo- campus or the lateral amygdala, and then investigated how these mini-infarcts affected brain functions associated with these regions. We found that rats with ET-1 infusion showed deficit in recall of contextual fear memory, but not in learning process and recall of tone fear memory. In novel object task, ET-1 in the hippocampus also elimi- nated object identity memory. ET-1 in the lateral amygdale affected acquisition of fear conditioning and disrupted retention of tone-conditioned fear, but did not impair retention of contextual fear. These findings suggest that ET-1- induced mini-infarct in deep brain area leads to functional deficits in learning and memory associated with these regions.

Quantitative proteomic and phosphoproteomic analyses of the hippocampus reveal the involvement of NMDAR1 signaling in repetitive mild traumatic brain injury

The cumulative damage caused by repetitive mild traumatic brain injury can cause long-term neurodegeneration leading to cognitive impairment.This cognitive impairment is thought to result specifically from damage to the hippocampus.In this study,we detected cognitive impairment in mice 6 weeks after repetitive mild traumatic brain injury using the novel object recognition test and the Morris water maze test.Immunofluorescence staining showed that p-tau expression was increased in the hippocampus after repetitive mild traumatic brain injury.Golgi staining showed a significant decrease in the total density of neuronal dendritic spines in the hippocampus,as well as in the density of mature dendritic spines.To investigate the specific molecular mechanisms underlying cognitive impairment due to hippocampal damage,we performed proteomic and phosphoproteomic analyses of the hippocampus with and without repetitive mild traumatic brain injury.The differentially expressed proteins were mainly enriched in inflammation,immunity,and coagulation,suggesting that non-neuronal cells are involved in the pathological changes that occur in the hippocampus in the chronic stage after repetitive mild traumatic brain injury.In contrast,differentially expressed phosphorylated proteins were mainly enriched in pathways related to neuronal function and structure,which is more consistent with neurodegeneration.We identified N-methyl-D-aspartate receptor 1 as a hub molecule involved in the response to repetitive mild traumatic brain injury,and western blotting showed that,while N-methyl-D-aspartate receptor 1 expression was not altered in the hippocampus after repetitive mild traumatic brain injury,its phosphorylation level was significantly increased,which is consistent with the omics results.Administration of GRP78608,an N-methyl-D-aspartate receptor 1 antagonist,to the hippocampus markedly improved repetitive mild traumatic brain injury-induced cognitive impairment.In conclusion,our findings suggest that N-methyl-D-aspartate receptor 1 signaling in the hippocampus is involved in cognitive impairment in the chronic stage after repetitive mild traumatic brain injury and may be a potential target for intervention and treatment.

Recombinant chitinase-3-like protein 1 alleviates learning and memory impairments via M2 microglia polarization in postoperative cognitive dysfunction mice

Postoperative cognitive dysfunction is a seve re complication of the central nervous system that occurs after anesthesia and surgery,and has received attention for its high incidence and effect on the quality of life of patients.To date,there are no viable treatment options for postoperative cognitive dysfunction.The identification of postoperative cognitive dysfunction hub genes could provide new research directions and therapeutic targets for future research.To identify the signaling mechanisms contributing to postoperative cognitive dysfunction,we first conducted Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analyses of the Gene Expression Omnibus GSE95426 dataset,which consists of mRNAs and long non-coding RNAs differentially expressed in mouse hippocampus3 days after tibial fracture.The dataset was enriched in genes associated with the biological process"regulation of immune cells,"of which Chill was identified as a hub gene.Therefore,we investigated the contribution of chitinase-3-like protein 1 protein expression changes to postoperative cognitive dysfunction in the mouse model of tibial fractu re surgery.Mice were intraperitoneally injected with vehicle or recombinant chitinase-3-like protein 124 hours post-surgery,and the injection groups were compared with untreated control mice for learning and memory capacities using the Y-maze and fear conditioning tests.In addition,protein expression levels of proinflammatory factors(interleukin-1βand inducible nitric oxide synthase),M2-type macrophage markers(CD206 and arginase-1),and cognition-related proteins(brain-derived neurotropic factor and phosphorylated NMDA receptor subunit NR2B)were measured in hippocampus by western blotting.Treatment with recombinant chitinase-3-like protein 1 prevented surgery-induced cognitive impairment,downregulated interleukin-1βand nducible nitric oxide synthase expression,and upregulated CD206,arginase-1,pNR2B,and brain-derived neurotropic factor expression compared with vehicle treatment.Intraperitoneal administration of the specific ERK inhibitor PD98059 diminished the effects of recombinant chitinase-3-like protein 1.Collectively,our findings suggest that recombinant chitinase-3-like protein 1 ameliorates surgery-induced cognitive decline by attenuating neuroinflammation via M2 microglial polarization in the hippocampus.Therefore,recombinant chitinase-3-like protein1 may have therapeutic potential fo r postoperative cognitive dysfunction.

The β-amyloid protein induces S100β expression in rat hippocampus through a mechanism that involves IL-1

Objective To explore the effect of β-amyloid protein (Aβ) on S100β expression in rat hippocampus and its mechanisms. Methods At 7 days after bilateral stereotaxis injection of different dose of fibrillar Aβ 25-35 and interluekin-1 receptor antagonist (IL-1ra) into the rat CA1 region, the learning and memory abilities of rats were tested with passive avoidance task. Amyloid deposition was detected by using Congo red staining technique. Nissl staining and immunohistochemical techniques were used to analyze the number of neurons, and GFAP and the S100β expression in hippocampal CA1 region , respectively. Results After fibrillar Aβ injection, the step-through latency of rats was significantly shortened compared to that of the control group. The GFAP positive astrocytes were found surrounding amyloid deposition. Neuronal loss occurred in the pyramidal cell layer of CA1 region. The number of S100β positive cells in Aβ-treated group was significantly increased compared with that in the control group. After IL-1ra injection, the number of S100β positive cells was significantly decreased. Conclusion Intrahippocampal injection of Aβ 25-35 could cause similar pathologic changes of Alzheimer’s disease. Aβ 25-35 was capable of up-regulating S100β expression in a dose-dependent manner. The injection of IL-1ra could attenuate the effect of Aβ on S100β expression.

Expression of fibroblast growth factor-2 and fibroblast growth factor receptor-1 protein in the hippocampus in rats exhibiting chronic stress-induced depression

There is evidence that the expression of members of the fibroblast growth factor （FGF） protein family is altered in post-mortem brains of humans suffering from major depressive disorder. The present study examined whether the expression of fibroblast growth factor-2 （FGF2） and fibroblast growth factor receptor-1 （FGFR1） protein is altered following chronic stress in an animal model. Rats were exposed to 35 days of chronic unpredictable mild stress, and then tested using open-field and sucrose consumption tests. Compared with the control group, rats in the chronic stress group exhibited obvious depressive-like behaviors, including anhedonia, anxiety and decreased mobility. The results of western blot analysis and immunohistochemical analysis revealed a downregulation of the expression of FGF2 and FGFR1 in the hippocampus of rats, particularly in the CA1, CA3 and dentate gyrus. This decreased expression is in accord with the results of post-mortem studies in humans with major depressive disorder. These findings suggest that FGF2 and FGFR1 proteins participate in the pathophysiology of depressive-like behavior, and may play an important role in the mechanism of chronic stress-induced depression.

Repetitive traumatic brain injury–induced complement C1–related inflammation impairs long-term hippocampal neurogenesis

Repetitive traumatic brain injury impacts adult neurogenesis in the hippocampal dentate gyrus,leading to long-term cognitive impairment.However,the mechanism underlying this neurogenesis impairment remains unknown.In this study,we established a male mouse model of repetitive traumatic brain injury and performed long-term evaluation of neurogenesis of the hippocampal dentate gyrus after repetitive traumatic brain injury.Our results showed that repetitive traumatic brain injury inhibited neural stem cell proliferation and development,delayed neuronal maturation,and reduced the complexity of neuronal dendrites and spines.Mice with repetitive traumatic brain injuryalso showed deficits in spatial memory retrieval.Moreover,following repetitive traumatic brain injury,neuroinflammation was enhanced in the neurogenesis microenvironment where C1q levels were increased,C1q binding protein levels were decreased,and canonical Wnt/β-catenin signaling was downregulated.An inhibitor of C1 reversed the long-term impairment of neurogenesis induced by repetitive traumatic brain injury and improved neurological function.These findings suggest that repetitive traumatic brain injury–induced C1-related inflammation impairs long-term neurogenesis in the dentate gyrus and contributes to spatial memory retrieval dysfunction.

Movement and behavior analysis using neural spike signals in CA1 of rat hippocampus

The hippocampus which lies in the temporal lobe plays an important role in spatial navigation,learning and memory.Several studies have been made on the place cell activity,spatial memory,prediction of future locations and various learning paradigms.However,there are no attempts which have focused on finding whether neurons which contribute largely to both spatial memory and learning about the reward exist.This paper proposes that there are neurons that can simultaneously engage in forming place memory and reward learning in a rat hippocampus' s CA1 area.With a trained rat,a reward experiment was conducted in a modified 8-shaped maze with five stages,and utterance information was obtained from a CA1 neuron.The firing rate which is the count of spikes per unit time was calculated.The decoding was conducted with log-maximum likelihood estimation(Log-MLE) using Gaussian distribution model.Our outcomes provide evidence of neurons which play a part in spatial memory and learning regarding reward.

氧化/还原因子ref-1在肺癌组织中的细胞定位表达及与8-OH-dG的关系

目的 氧化 /还原因子 1(ref 1) ,也称为AP核酸内切酶 (APE) ,是氧化还原和DNA碱基切除修复途径中的重要一员。本研究旨在探讨ref 1在肺癌中的表达及其与氧化损伤标志 8 羟基 脱氧鸟苷 (8 OH dG)的关系。方法 用免疫组化法检测15 0例肺癌组织、12 0例癌旁肺组织、4 0例肺良性病变和 4 0例正常肺组织中氧化 /还原因子ref 1基因的蛋白质表达 ;分析有关暴露因素对ref 1表达的影响 ,探讨ref 1基因与 8 OH dG的关系。结果 肺癌和正常肺组织皆有ref 1的表达 ,但ref 1在细胞内的定位有所不同 ,70 .0 % (10 5 / 15 0 )的肺癌组织ref 1从通常的胞核定位移位到胞浆 ,仅 7.5 % (3/ 4 0 )的正常肺组织有ref 1移位胞浆的现象 ,两者差异显著 ,P <0 .0 1。未发现肺癌患者的性别、年龄、吸烟和肿瘤家族史等因素与ref 1细胞定位之间有联系。ref 1移位胞浆与肺组织中 8 OH dG的含量呈显著正相关 ,Spearman相关系数为 0 .70 2 ,P <0 .0 1。结论 ref 1的细胞定位对其氧化 /还原和修复功能有着重要影响 ,可作为监测细胞DNA修复功能的指标。

姜黄素对缺血/再灌注大鼠APE/Ref-1表达及细胞凋亡的影响

目的观察姜黄素对大鼠全脑缺血/再灌注损伤后海马神经元凋亡与DNA修复蛋白APE/Ref-1表达的影响,探讨其对脑缺血损伤后的保护作用。方法将144只雄性SD大鼠随机平均分为假手术组(SO组)、缺血/再灌注组(IR组)和姜黄素干预组(CU组)各48只。建立大鼠全脑缺血/再灌注模型,CU组于再灌注后即刻经腹腔注射姜黄素。分别于再灌注后2、6、12、24、48、72 h处死大鼠,提取大鼠脑组织。原位末端标记法检测海马CA1区的细胞凋亡情况;免疫组化SABC法检测APE/Ref-1的表达。结果 SO组神经元细胞凋亡较少,IR组凋亡的神经元细胞于再灌注6 h开始增多,48 h细胞凋亡率达到最高。与SO组比较,IR组细胞凋亡率增高(P<0.01)。CU组在再灌注6 h后的各时点神经元细胞凋亡较IR组少(P均<0.01)。SO组APE/Ref-1阳性细胞在各时点较多;IR组于再灌注后2 h APE/Ref-1阳性细胞开始出现明显减少,一直持续至72 h,与SO组比较有统计学差异(P均<0.01);CU组APE/Ref-1阳性细胞率各时点与IR组比较均有统计学差异(P均<0.01)。结论姜黄素发挥脑保护作用的机制可能与减缓DNA修复蛋白APE/Ref-1表达的下降和阻止脑缺血/再灌注损伤区神经元细胞的凋亡有关。

PC12细胞APE/ref-1cDNA的克隆和表达

APE Ref 1是双功能核蛋白 ,它既能在碱基切除修复过程中切除脱嘌呤 脱嘌啶位点 ,又能促进包括AP 1、Myb和NF κB等受氧化还原调节的转录因子对DNA的结合 .从PC12细胞中抽提总RNA ,经逆转录PCR(RT PCR)扩增出APE ref 1cDNA并克隆到pQE3 1表达质粒上的BamHⅠ和PstⅠ位点间 .经测序表明 ,PC12细胞的APE ref 1cDNA以正确的阅读框架重组进入表达质粒 ,表达重组质粒pQE3 1 APE在宿主菌BL2 1中得到稳定表达 .SDS PAGE鉴定表明 ,带 6个组氨酸的融合蛋白分子量为 3 8kD ,并经Ni NTA琼脂糖亲和纯化得到电泳纯融合蛋白 .Western印迹证明重组蛋白为APE ref 1融合蛋白 .

吉西他滨对人肺癌A549细胞株CN-Ⅱ，APE／Ref-1mRNA和蛋白表达的影响

【目的】研究人肺癌A549细胞株在吉西他滨化疗时CN-Ⅱ,APE/Ref-1基因表达的变化,并探讨其在肺癌化疗耐药中所起的作用。【方法】不同浓度吉西他滨0、10、20、40及60μmol/L作用人肺癌A549细胞株24h,分别以RT-PCR及Western blot方法测定用药后CN-Ⅱ和APE/Ref-1的mRNA及蛋白表达情况。【结果】吉西他滨作用人肺癌A549细胞株24h后,CN-Ⅱ和APE/Ref-1的mRNA及蛋白表达水平均明显上升,并与吉西他滨的浓度呈正相关(CN-ⅡRT-PCR:r=0.687,P=0.009;Western blot:r=0.594,P=0.021;APE/Ref-1RT-PCR:r=0.669,P=0.010;Western blot:r=0.562,P=0.029)。【结论】CN-Ⅱ和APE/Ref-1在肺癌化疗时表达明显增强,可能与化疗耐药性的产生有关,并提示针对CN-Ⅱ和APE/Ref-1的靶向干预可能有助于提高肺癌的化疗敏感性。

APE1/Ref-1、EGR-1在食管鳞癌中的表达及相关性研究

目的本研究旨在明确APE1/Ref-1和EGR-1在食管鳞癌及癌旁组织中的表达情况,并结合临床资料评估其表达与组织分级和临床分期之间的关系,为进一步研究食管鳞癌的发生发展机制提供参考依据,并为食管鳞癌的预防、诊治提供临床指标。方法随机选取2009至2010年接受胸外科手术治疗的86例食管癌标本,术前均未经放化疗等任何抗癌治疗。采用免疫组织化学法(S-P法)测定APE1/Ref-1的蛋白、EGR-1的蛋白表达情况,对其相关性进行分析。结果 APE1/Ref-1在ESCC组织中细胞质和细胞核联合阳性表达率为68.6%明显高于癌旁组织的联合阳性表达率8.1%,差异有统计学意义(P<0.01)。APE1/Ref-1在癌旁组织中的细胞核阳性表达率为91.9%明显高于ESCC组织的24.4%,差异有统计学意义(P<0.01)。EGR-1在ESCC组织的阳性表达率显著低于癌旁组织(P<0.01)。结论在ESCC中,APE1/Ref-1胞核胞质联合表达率随着组织学分级降低和临床分期的升高有增强的趋势,EGR-1的阳性表达率随着组织学分级降低和临床分期的升高有降低的趋势。

Ref-1在阿尔茨海默病大鼠海马CA1区表达的研究

目的:探讨Ref-1在阿尔茨海默病(AD)大鼠发病中的变化及其可能机制。方法:采用Aβ25-35单次侧脑室注射诱导AD大鼠模型,Y迷宫测定大鼠行为学变化,免疫组化法检测建模后4d、7d和14d时痴呆组、对照组大鼠海马CA1区Ref-1的表达。结果:1Aβ注射7d、14d后,痴呆组大鼠达到学习标准的训练次数、错误次数和全天总反应时间较对照组均明显增加(P<0.05)。2痴呆组Aβ注射4d起,海马CA1区Ref-1表达开始增高(P<0.01),随着观察时点的延长,这种表达进一步增高(P<0.01)。结论:大鼠侧脑室注射Aβ7d可成功诱导AD大鼠模型;Ref-1的上调早于大鼠记忆障碍的发生,Ref-1可能参与了AD的发生发展。

APE1/Ref-1线粒体定位机制的研究

APE1/Ref-1是一种重要的多功能蛋白,主要功能是DNA修复和转录因子的氧化还原调控。目前认为,核编码基因的线粒体主动转运主要依靠线粒体外膜和内膜上一系列转运酶复合体,称为外膜转运酶（translocase of outer membrane,TOM）和内膜转运酶（translocase of inner membrane,TIM）。基本过．程为线粒体外膜TOM复合体中的受体亚基，包括TOM20、TOM22和TOM70识别前体蛋白上的线粒体定位信号，而后通过TOM40等亚基形成的共同转运通道（general import pore，G1P）进入线粒体。

APE1/Ref-1与肿瘤的研究进展

脱嘌呤脱嘧啶核酸内切酶1又称氧化还原因子-1,是一种双功能酶,不仅具有核酸内切酶活性,发挥DNA修复功能,而且具有氧化还原功能,调控多种重要转录因子的活性。目前研究发现APE1/Ref-1在人体多种肿瘤中表达且与肿瘤的发生、发展及预后相关。APE1/Ref-1可能成为极具潜力的肿瘤基因治疗的新靶点。本文就APE1/Ref-1的结构、功能及在肿瘤研究方面的进展作了一系列的回顾与总结。

肾细胞癌中Ref-1/APE的表达特点及其意义

目的探讨Ref-1/APE蛋白表达与肾细胞癌生物学行为的关系。方法应用免疫组织化学方法检测58例肾细胞癌和11例正常肾组织中Ref-1/APE的表达。结果所有肾细胞癌和正常肾组织均有Ref-1/APE的表达,但在细胞内的表达定位有所不同,肾细胞癌阳性颗粒表达部位以细胞核为主,并且Ref-1/APE的表达定位与肿瘤分级、分期密切相关,差异有显著性(P<0.01);11例正常肾组织中仅见肾小管上皮细胞表达。结论Ref-1/APE基因可能与肾细胞癌的发生、发展有关。检测Ref-1/APE的表达及移位于细胞质的情况可能为肾细胞癌的恶性程度判定、预后评估及进一步治疗提供依据。

视网膜缺血再灌注损伤中Ref-1的表达及bFGF对其的影响

目的研究缺血再灌注损伤视网膜组织中无嘌呤/无嘧啶核酸内切酶/氧化还原因子-1(APE/Ref-1,Ref-1)表达的变化及玻璃体腔内注射碱性成纤维细胞生长因子(bFGF)对其的影响。方法建立大鼠视网膜缺血再灌注损伤动物模型,于再灌注开始即刻玻璃体腔内注射bFGF2μg,利用SABC免疫组织化学法检测不同时段Ref-1蛋白在视网膜组织表达的变化,分析Ref-1蛋白与细胞凋亡的关系以及bFGF对其表达的影响。结果Ref-1蛋白在视网膜组织中的表达随着缺血再灌注时间的延长明显减少。bFGF治疗组Ref-1蛋白表达规律与缺血组相同,但其阳性表达率较同一时段缺血再灌注组有所增加。结论大鼠玻璃腔注射bFGF,可以上调Ref-1的表达,对视网膜缺血再灌注损伤起到修复的作用。

大鼠耳蜗缺血再灌注后APE/Ref-1表达研究

目的观察APE/Ref-1在正常成年SD大鼠内耳蜗缺血再灌注后的表达变化。方法成年SD大鼠24只,随机分成2组(n=12),分别为假手术对照组、缺血再灌注组。各组动物于再灌注24h取出左侧耳蜗,每组随机4个耳蜗,石蜡包埋切片,行免疫组织化学观察APE/Ref-1表达分布。各组余下耳蜗组织进行均浆,进行免疫印记实验,测定匀浆中APE/Ref-1蛋白表达。结果与假手术对照组相比,缺血再灌注组APE/Ref-1蛋白表达显著增加(P<0.05)。在假手术组大鼠耳蜗中,APE/Ref-1主要表达在正常螺旋神经节区,细胞内定位在细胞浆和细胞核,螺旋韧带和血管纹也可以见到表达。缺血再灌注组APE/Ref-1在耳蜗这些部位的表达显著增加。结论正常大鼠内耳表达APE/Ref-1,主要表达在螺旋神经节区。耳蜗缺血再灌注后,APE/Ref-1在内耳的表达显著增加,提示APE/Ref-1可能与耳蜗缺血再灌注氧化损伤密切相关。