CRMP2在大鼠海马神经元中的表达分布及对神经元突起生长的影响

目的探讨脑衰反应调节蛋白2(CRMP2)在大鼠海马神经元中的表达分布及对神经元突起生长的影响。方法CRMP2及其模拟磷酸化质粒CRMP2-S522D、CRMP2-T555D,转入体外培养的SD大鼠海马神经元,转染72 h后,采用免疫印迹法和免疫荧光染色分析CRMP2、CRMP2-S522D、CRMP2-T555D在神经元中的分布差异以及对神经元突起分枝和突起长度的影响。结果 CRMP2及CRMP2-T555D在神经元胞体和突起均有分布,CRMP2-S522D则主要分布于胞体。CRMP2-T555D对神经元的突起长度和分枝数均没有明显影响;CRMP2-S522D对突起数目没有明显影响,但可以显著降低突起长度。结论 CRMP2的不同磷酸化形式在大鼠海马神经元中存在分布差异,并对神经元的突起长度产生影响。     

脑积水相关分子信号通路的研究进展

脑积水的形成和发展是多因素导致的复杂病理过程,近来研究发现许多关键信号通路的异常表达与脑积水关系密切,如TGF-β信号通路、Wnt信号通路等多条信号通路。脑积水相关分子信号通路的异常激活可导致颅内多种细胞失去稳态异常增殖,引起下游蛋白的表达异常和胶原等细胞外基质合成增多,导致脑脊液分泌增加及循环吸收障碍,从而导致了脑积水的产生。本文就脑积水相关的重要分子信号转导通路进行综述,希望找到脑积水病因中的重要靶点,从而进行病因治疗,为寻找脑积水的发病机制以及探索新的治疗方案提供新的思路。     

胶质瘤相关Hedgehog信号通路的研究进展

胶质瘤是中枢神经系统最常见的原发性恶性肿瘤,传统治疗主要包括肿瘤切除、放疗及化疗,但肿瘤侵袭性强,术后复发率高.Hedgehog这一高度保守的细胞信号传导通路,广泛参与胚胎的发育和多种病理生理过程,且许多研究已证实该通路在较高比例的胶质瘤中异常活化,在肿瘤发生、发展中的作用也逐渐揭示.这为研究胶质瘤的发病机制及诊断治疗提供新的思路.本文就Hedgehog通路在胶质瘤中的研究进展进行综述.     

髓样触发受体2及其相关信号通路在阿尔茨海默病中的研究进展

阿尔茨海默病(AD)是一种进行性发展的神经退行性疾病,是导致老年人痴呆最主要的原因.AD的病理学主要表现为细胞外β淀粉样蛋白(Aβ)聚集和细胞内神经纤维缠结(NFT)形成.髓样细胞触发受体2(TREM2)主要在小胶质细胞和星形胶质细胞的细胞膜上表达,其突变可提高AD的发病风险,与配体结合可激活下游信号通路,调节小胶质细...     

脑胶质瘤干细胞Hedgehog信号通路研究进展

脑胶质瘤是中枢神经系统发病率和复发率最高的恶性肿瘤,因其呈浸润性生长,手术、放疗及化疗等治疗手段均难以根治。随着对神经干细胞入了解和肿瘤干细胞概念的提出,有学者成功分离出脑胶质瘤干细胞（glima stem cells,GSCs）,这为有效的治疗脑胶质瘤的研究提供了锲机,也成为神经外科领域的研究热点。Hedgehog信号通路广泛参与胚胎的发育以及多种病理生理过程。     

毛囊干细胞参与创伤修复及相关信号通路

皮肤的毛囊干细胞具有多分化潜能,可以分化成毛干、内髓鞘、外髓鞘、和皮肤表皮角质细胞以及皮脂腺,毛囊干细胞作为皮肤中储存的主要干细胞在维持毛囊周期和表皮创伤修复中都发挥重要作用。毛囊细胞参与创伤后表皮修复的过程研究相对较早,但对于毛囊干细胞参与此过程的研究近些年较为深入,这些过程受不同的信号通路调节,包括Wnt、BMP、FGF、Notch、SHH等。文章综述了毛囊干细胞如何参与表皮创伤修复及相关信号转导通路调节机制的研究现状,加深毛囊干细胞在临床中构建皮肤组织工程以及在整形美容医学应用中的理解。     

硫化氢与MAPK/Nrf2信号通路关系的研究进展

生理浓度的硫化氢(H_2S)可抑制JNK、P 38和ERK1/2磷酸化,促使Nrf2的活化,发挥减轻氧化应激反应、炎症和抗凋亡等作用。MAPK信号通路生理作用复杂,体外实验发现H_2S通过抑制P 38、ERK和JNK磷酸化,从而抑制胶原诱导的血小板聚集,其与肿瘤细胞的增殖和凋亡密切相关,目前以成为攻克肿瘤的一个重要靶点。另外,MAPK信号通路信号分子间交叉交互作用及H_2S与ERK3/4和ERK5信号转导途径之间关系还有待进一步研究。该综述介绍了H_2S与MAPK(ERKs、ERK5、JNK和p38 MAPK)信号转导途径及Nrf2的生理功能及关系。     

三七总皂甙通过细胞外信号调节蛋白激酶1/2信号通路促进大鼠

背景：三七总皂甙对骨髓基质细胞向神经样细胞分化的效应及相关信号通路目前尚不明确。 目的：探讨细胞外信号调节蛋白激酶1/2信号通路对三七总皂甙调节大鼠骨髓基质细胞向神经细胞增殖、分化的作用。 设计、时间及地点：细胞学体外观察,于2008-05/10在汕头大学医学院分子生物学实验室完成。 材料：4~6周龄雄性SD大鼠9只,由汕头大学医学院实验动物中心提供。三七总皂甙为广西梧州制药集团股份有限公司产品,细胞外信号调节蛋白激酶的抑制剂PD98059为Cell Signaling Tech 公司产品。 方法：全骨髓法体外分离纯化大鼠骨髓基质细胞,取传至第3代细胞进行诱导分化,设立3组：单纯诱导组向培养液中加入10 μg/L碱性成纤维细胞生长因子,预诱导24 h后全量换为正式诱导液(含10 μg/L碱性成纤维细胞生长因子、2% DMSO、200 μmol/L丁羟回醚的α-MEM培养基),每24 h半量换诱导液1次;三七总皂甙组向预诱导液和正式诱导液内加入终浓度100 mg/L三七总皂甙;PD98059组在三七总皂甙组培养液基础上加入10 μmol/L PD98059。 主要观察指标：细胞形态学观察,MTT法检测细胞增殖情况,免疫组织化学方法鉴定细胞Nestin的表达。 结果：诱导6 h后,少数细胞呈锥形,细胞突起增多伸长,类似神经元,继续诱导培养后细胞突起增多,突起相互连接成网状。与单纯诱导组、PD98059组比较,诱导6,12,24 h三七总皂甙组细胞均明显增殖(P < 0.05),且随诱导时间延长呈递增趋势(P < 0.05);单纯诱导组、PD98059组间比较无明显差异(P > 0.05)。与单纯诱导组比较,诱导24 h后三七总皂甙组Nestin阳性率明显升高(P < 0.05),PD98059组Nestin阳性率明显降低(P < 0.05)。 结论：三七总皂甙可以促进骨髓基质细胞的神经分化和分化后增殖,细胞外信号调节蛋白激酶1/2的特异性抑制剂PD98059能够拮抗三七总皂甙促增殖分化作用,提示细胞外信号调节蛋白激酶1/2信号通路是三七总皂甙促进骨髓基质细胞向神经细胞分化和增殖的重要环节。     

核转录相关因子2—抗氧化反应元件信号通路在认知障碍相关疾病中的作用

核转录相关因子2-抗氧化反应元件(Nrf2-ARE)信号通路是机体内最重要的抗氧化应激通路之一。近年来研究发现,在血管性痴呆、阿尔兹海默病、帕金森病等认知障碍相关的疾病中,机体可以通过激活Nrf2-ARE信号通路来增加内源性的抗氧化能力,最终使认知功能得到改善。因此,本文旨在对Nrf2-ARE信号通路的组成、调节及其与认知障碍相关疾病的关系作一综述。     

Differential expression of CRMP1, CRMP2A, CRMP2B, and CRMP5 in axons or dendrites of distinct neurons in the mouse brain

CRMP1, CRMP2, and CRMP5 have been identified as cytosolic proteins relaying semaphorin 3A signalling, one of the molecular cues conducting axon and dendrite growth and guidance. They are highly expressed during brain ontogenesis, but, because of their lower levels in the adult, their distribution in the mature brain is poorly documented. By using specific antibodies, we investigated the cellular distribution of these CRMPs in different adult brain structures and in neural cell cultures with a special focus on the splice variants CRMP2A and CRMP2B. In brain sections of adult mouse, CRMP1, CRMP2B, and CRMP5 were located predominantly in dendrites of specific neuronal populations, such as cortical pyramidal neurons, hippocampal CA1 pyramidal cells, or Purkinje cerebellar cells. On the contrary, CRMP2A was specifically associated with axons of the corpus callosum, bundles of the striatum, and mossy fibers of the hippocampus. In cultures of cortical neurons, CRMP1, CRMP2A, CRMP2B, and CRMP5 were equally distributed throughout cell bodies, axons, or dendrites of neurons, whereas CRMP2A and CRMP5 were completely absent from Purkinje cerebellar cells in 12-day-old animals. By comparison, oligodendrocytes exclusively express CRMP2B and CRMP5 in cell bodies and processes both in situ in the adult brain and in primary cultures. Overall, our results demonstrate specific subcellular localizations of CRMP1, CRMP2A, CRMP2B, and CRMP5 depending on cell types, neuronal compartment, and developmental stage. This study suggests that, beyond their signalling function in axon outgrowth and guidance, CRMPs also play a role in mature neurons both in axons and in dendrites.     

Post-translational protein modification as the substrate for long-lasting memory

Prevailing models of memory identify mRNA translation as necessary for long-lasting information storage. However, there are enough instances of memory storage in the virtual absence of protein synthesis to prompt consideration of alternative models. A comprehensive review of the protein synthesis literature leads us to conclude that the translational mechanism is exclusively a permissive, replenishment step. Therefore, we propose that post-translational modification (PTM) of proteins already at the synapse is the crucial instructive mechanism underlying long-lasting memory. A novel feature of this model is that non-random spontaneous (or endogenous) brain activity operates as a regulated positive-feedback rehearsal mechanism, updating network configurations by fine-tuning the PTM state of previously modified proteins. Synapses participating in memory storage are therefore supple, a feature required for networks to alter complexity and update continuously. In analogy with codons for amino acids, a long-lasting memory is represented by a 'degenerate code' - a set of pseudo-redundant networks that can ensure its longevity.     

Age-dependent alterations in CRMP2 and CRMP4 protein expression profiles in cat visual cortex

We monitored the protein expression profiles of collapsin response mediator protein 2 and 4 (CRMP2 and CRMP4) throughout cat primary visual area 17 at different postnatal ages. Single immunocytochemical stainings revealed a clear effect of cortical maturation on the spatial and laminar distribution profile of CRMP2 and CRMP4. In kittens of postnatal day 10 (P10) and 30 (P30), CRMP2 and CRMP4 immunoreactivity was exclusively present in fibers running perpendicular to the cortical surface and crossing all cortical layers, but was never found in neuronal cell bodies. The immunoreactive fibers were embedded in an intensely and homogeneously stained neuropil. In contrast, mature visual cortex immunocytochemistry located CRMP2 and CRMP4 in the somatodendritic compartment of neurons with a clear CRMP-specific lamination pattern. Similar to kitten, neuropil staining was clearly observed but showed a decreasing gradient from layer I to VI in adult area 17. Detailed analysis of cellular morphology and size classified the CRMP2- and CRMP4-immunopositive cells in distinct neuronal populations. Double labeling of CRMP2 or CRMP4 with the typical interneuron marker parvalbumin (PV) showed many double-labeled cells immunoreactive for CRMP4 and PV, but not for CRMP2 and PV, corroborating the cell type-specific character of each CRMP. Our present results clearly illustrate that CRMP2 and CRMP4 may play an important role in visual cortex, possibly providing different classes of neurons with the potential to form a functionally meaningful network, not only during development, but also in adulthood, coincident with the belief that CRMPs are involved in neurite growth and guidance.     

Post-translational oxidative modification and inactivation of mitochondrial complex I in epileptogenesis

Mitochondrial oxidative stress and damage have been implicated in the etiology of temporal lobe epilepsy, but whether or not they have a functional impact on mitochondrial processes during epilepsy development (epileptogenesis) is unknown. One consequence of increased steady-state mitochondrial reactive oxygen species levels is protein post-translational modification (PTM). We hypothesize that complex I (CI), a protein complex of the mitochondrial electron transport chain, is a target for oxidant-induced PTMs, such as carbonylation, leading to impaired function during epileptogenesis. The goal of this study was to determine whether oxidative modifications occur and what impact they have on CI enzymatic activity in the rat hippocampus in response to kainate (KA)-induced epileptogenesis. Rats were injected with a single high dose of KA or vehicle and evidence for CI modifications was measured during the acute, latent, and chronic stages of epilepsy. Mitochondrial-specific carbonylation was increased acutely (48 h) and chronically (6 week), coincident with decreased CI activity. Mass spectrometry analysis of immunocaptured CI identified specific metal catalyzed carbonylation to Arg76 within the 75 kDa subunit concomitant with inhibition of CI activity during epileptogenesis. Computational-based molecular modeling studies revealed that Arg76 is in close proximity to the active site of CI and carbonylation of the residue is predicted to induce substantial structural alterations to the protein complex. These data provide evidence for the occurrence of a specific and irreversible oxidative modification of an important mitochondrial enzyme complex critical for cellular bioenergetics during the process of epileptogenesis.     

Post-translational modification and evoked release of two large surface proteins of sympathetic neurons

Two high molecular weight glycoproteins, exposed on the surface of sympathetic neurons, are modified after they have been translated, glycosylated, and inserted in the plasma membrane. B1 (apparent Mr = 230,000 by electrophoresis in sodium dodecyl sulfate) and B3 (Mr approximately 200,000) are each modified to give proteins of lower apparent molecular weight: B2 (Mr approximately 215,000) and B4 (Mr approximately 185,000). B1 and B3 are derived from two precursors, P1 (Mr approximately 210,000) and P3 (Mr approximately 185,000) which are nonsialylated, mannose-rich proteins not exposed on the cell surface. In unstimulated cells, B1 and B3 are converted to B2 and B4 with a half-life of 4 to 6 hr. In cells which have been treated chemically to evoke the release of neurotransmitter, the modification appears to be accelerated, and B2 and B4 are shed into the medium in soluble form (S2 and S4). This evoked release of protein is calcium dependent and is detected only in conditions which favor the rapid release of neurotransmitter. In the absence of exogenous calcium, however, transmitter release can be evoked without the accompanying release of protein. Thus the release of protein is not an essential step of transmitter release, but may follow it. B1, its precursor, and derivatives are immunologically related to the NILE (nerve growth factor-inducible, large external) glycoprotein of pheochromocytoma PC12 cells (McGuire, J. C., L. A. Greene, and A. V. Furano (1978) Cell 15: 357-365). B3 does not cross-react with B1 or NILE antigenically, but otherwise is synthesized, processed, and released in a similar manner.     

Differential age- and disease-related effects on the expression of genes related to the arachidonic acid signaling pathway in schizophrenia

We have previously identified differential effects of age on global brain gene expression profiles in subjects with schizophrenia compared to normal controls. Here, we have focused on age-related effects of genes associated with the arachidonic acid-related inflammation pathway. Linear correlation analysis of published microarray expression data reveal strong age- and cell-type- specific-effects on the expression of genes related to the arachidonic acid signaling pathway, which differed in control subjects compared to those with schizophrenia. Using real-time qPCR analysis, we validated age and disease effects of arachidonic acid-related genes in a large cohort of subjects with schizophrenia and matched controls (n=76 subjects in total). We found that levels of prostaglandin-endoperoxide synthase 1 (PTGS1; aka COX-1) and prostaglandin-endoperoxide receptor 3 (PTGER3) mRNA are increased, and levels of prostaglandin-endoperoxide synthase 2 (PTGS2; aka COX-2) mRNA are decreased, in older subjects with schizophrenia (> 40years of age) compared to matched normal controls or younger subjects with schizophrenia (< 40years of age). These findings contribute to the accumulating evidence suggesting that inflammatory processes in the CNS contribute to pathophysiology of schizophrenia and further suggest that age may be an important factor in the potential use of anti-inflammatory therapies.     

Expression of the onconeural CV2/CRMP5 antigen in thymus and thymoma

Anti-CV2 antibodies (AB) react with the developmentally regulated neural proteins CRMPs and particularly with CRMP5. They occur with small cell lung cancer (SCLC) and thymoma. SCLCs universally express CRMP5. We investigated the expression of CRMPs in thymoma and thymus. In thymoma, none of the CRMPs were detected by immunohistochemistry in tumorous epithelial cells with specific antibodies including CRMP5 but an antibody reacting with a peptide common to the CRMPs labeled a 66-kDa protein in Western blot of rat brain, thymus, and thymoma extracts. Thus, the normal CRMP5 is probably not expressed by tumorous epithelial cells. These results indicate that the mechanisms leading to CRMP5 autoimmunization are different in SCLC and thymoma.     

Effect of binocular retinal lesions on CRMP2 and CRMP4 but not Dyn I and Syt I expression in adult cat area 17

Removal of retinal input from a restricted region of adult cat visual cortex leads to a substantial reorganization of the retinotopy within the sensory-deprived cortical lesion projection zone (LPZ). Still little is known about the molecular mechanisms underlying this cortical map reorganization. We chose two members of the collapsin response mediator protein (CRMP) family, CRMP2 and CRMP4, because of their involvement in neurite growth, and compared gene and protein expression levels between normal control and reorganizing visual cortex upon induction of central retinal lesions. Parallel analysis of Dynamin I (Dyn I) and Synaptotagmin I (Syt I), two molecules implicated in the exocytosis-endocytosis cycle, was performed because changes in neurotransmitter release have been implicated in cortical plasticity. Western blotting and real-time polymerase chain reaction revealed a clear time-dependent effect of retinal lesioning on CRMP2 and CRMP4 expression, with maximal impact 2 weeks post-lesion. Altered CRMP levels were not a direct consequence of decreased visual activity in the LPZ as complete surgical removal of retinal input to one hemisphere had no effect on CRMP2 or CRMP4 expression. Thus, CRMP expression is correlated to cortical reorganization following partial deafferentation of adult visual cortex. In contrast, Dyn I and Syt I were not influenced and thereby do not promote exocytosis-endocytosis cycle modifications in adult cat cortical plasticity.     

Hedgehog信号通路与骨发育**

背景：Hedgehog作为骨发育中一种重要调控因子,近几年其在骨生长中作用机制的研究备受关注。目的：介绍Hedgehog在软骨组织和骨组织发育中的作用机制及其与骨疾病的关系,从而分析Hedgehog信号通路与骨发育的研究现状及发展趋势。方法：应用计算机检索中国期刊全文数据库和PubMed 数据库,以“Hedgehog,骨发育,间充质干细胞,软骨,成骨,骨缺陷”和“Hedgehog,bone development,mesenchymal stem cells,cartilage,osteogenesis,bone defects”为检索词。最终共纳入31篇文献进行综述。结果与结论：Hedgehog信号与骨发育各阶段密切相关,包括间充质细胞向骨细胞分化,软骨组织和骨组织形成等各方面。其信号通路传导异常会导致各种骨畸形或骨缺陷。但是Hedgehog信号在骨发育中的详细作用机制体系尚未完善,相关动物实验技术尚未成熟,国内外尚未出现相关临床实验。由于Hedgehog即参与骨发育,又参与某些胚胎组织的血管重新形成和成年哺乳动物的血管发生,因而有望在修复骨缺损的同时解决骨组织工程血管化的问题。Hedgehog信号通路的研究在骨组织工程及临床基因干预治疗等领域有广阔的前景。     

胰岛素信号通路与阿尔茨海默病

随着世界范围内滚滚袭来的“银发浪潮”,老化相关疾病的发病率呈逐年上升趋势.阿尔茨海默病(Alzheimer Disease,AD)是一种中枢神经系统退行性疾病,通常发生在老年期甚至老年前期,临床上以进行性认知功能障碍为主要特征,伴有行为学和精神心理方面的异常,晚期生活无法自理,已经成为威胁老年人身心健康的杀手之一.