马钱子苷对小胶质细胞活化的抑制作用

为探讨不同浓度的马钱子苷对小胶质细胞活化的抑制作用及其相关分子机制，分离培养了小鼠原代小胶质细胞，用不同浓度的马钱子苷（50、100、200 μmol/L）预处理后，利用脂多糖（lipopolysacharide,LPS）诱导其活化。观察马钱子苷对LPS诱导的小胶质细胞活化、炎症因子释放以及NF-κB信号通路的影响。结果显示:与对照组相比，LPS组小胶质细胞胞体膨大，分泌大量炎症细胞因子，且NF-κB核转移程度增加（P<0.05），小胶质细胞呈明显的M1型活化状态；低、中、高浓度的马钱子苷干预后，小胶质细胞的细胞总面积和细胞核面积显著减少（P<0.05）；中、高浓度的马钱子苷能使TNF-α、IL-6和IL-1β的mRNA表达水平降低（P<0.05）；中浓度的马钱子苷下调TNF-α和IL-1β的蛋白质水平（P<0.05）；此外低、中、高浓度的马钱子苷可以抑制小胶质细胞内iNOS表达和NF-κB信号通路激活。上述结果表明，马钱子苷可明显抑制小胶质细胞活化，减少炎症因子释放，其作用机制可能与抑制NF-κB信号通路有关。这为马钱子苷应用于神经炎症的预防和治疗奠定了理论基础。     

诱导MSCs转分化为视网膜神经样细胞的应用

近年来,人们研究发现骨髓间充质干细胞(mesenchymal stem cells,MSCs)在体外可经生长因子诱导,抗氧化剂诱导,中药诱导,增加细胞内cAMP等不同途径的诱导方法,分化为神经外胚层来源的神经元及神经胶质细胞,因此一些研究者尝试以上诱导途径使MSCs分化为视网膜神经样细胞,用于体内相关疾病的细胞替代治疗,为多种疾病带来了新的治疗思路。     

小胶质细胞内的钙离子信号的研究进展

细胞内钙离子(Ca~(2+))对多种生理活动均具有一定的调节作用,它可影响神经递质释放和细胞兴奋性.细胞内钙离子浓度([Ca~(2+)]i)受到多方面调控,[Ca~(2+)]i的变化是重要的信号转导方式之一.小胶质细胞是中枢神经系统中固有的免疫细胞,它们对脑损伤、脑炎症和多种神经退行性疾病有先天性的免疫应答.除了在疾病发生发展中的作用,小胶质细胞也在很大程度上参与了神经元网络的发育和脑组织稳态的维持.受体介导的钙离子信号的传递,是包括小胶质细胞在内的所有细胞中最普遍的信号转导机制.小胶质细胞功能变化与小胶质细胞内钙离子信号的变化密切相关,对小胶质细胞内钙离子信号的研究具有重大的意义.     

RNA抑制技术在神经干细胞研究中的应用

神经干细胞是在神经系统中发现的一种可以再生的细胞，不仅具有自我复制能力，还可以分化为神经元、星状胶质细胞和少突胶质细胞，对研究神经退行性疾病和神经系统的发育过程产生很大的影响，因而在国际上形成了一个研究热点，但其增殖、分化乃至迁移的机制仍有待解决，RNA抑制技术是目前流行的基因沉默法，利用导入小片段核酸进入细胞，对特定基因表达的翻译阶段进行抑制，从而观察基因对细胞的影响，该文在已获得分化相关基因的基础上，利用RNA干扰(RNAi)和反义RNA(antisense RNA)法检测几个基因对神经干细胞的影响。     

雷公藤甲素通过调控NLRP3通路抑制LPS诱导的BV2小胶质细胞炎性反应

目的 基于炎症小体（NLRP3）通路探讨雷公藤甲素（Triptolide TP）抑制小胶质细胞炎性反应的机制。方法 脂多糖（LPS）刺激BV2小胶质细胞促细胞炎症损伤,建立体外模型,观察TP对LPS刺激的小胶质细胞的影响。BV2小胶质细胞分为对照组、LPS诱导的模型组(1 mg/L LPS)、TP组(1 nmol/L TP+1 mg/L LPS)。对照组不做处理,其它组药物作用24 h,镜下观察药物组细胞发生的形态变化并和对照组比较;细胞上清液用Griess法测定一氧化氮(NO)的释放量;免疫荧光染色和Western blot法检测各组细胞间炎症小体蛋白3(NLRP3)、凋亡相关斑点样蛋白（ASC）、半胱氨酸天冬氨酸蛋白酶（caspase-1）和白细胞介素-18(IL-18)的水平差别。结果 LPS诱导BV2细胞炎性活化,形态呈阿米巴样,降低细胞活性,促进NO的释放。TP作用后降低NO水平,使NLRP3炎性小体激活受到抑制,NLRP3、ASC、caspase-1和IL-18表达水平低下。结论 TP对小胶质细胞炎性反应有抑制作用,发挥了TP的抗炎作用,抑制了NLRP3炎性小体的活化和表达...     

小胶质细胞在不同炎性环境下亚型和功能的演变及其意义

近年来随着对多种神经系统炎性变性病如阿尔茨海默氏病(AD)、帕金森氏病(PD)和多发性硬化(MS)等发病机制的深入研究,显示脑内慢性免疫炎症反应可能是其重要病理特征之一,而小胶质细胞在其中所起的重要作用也日益受到人们的关注。小胶质细胞是中枢神经系统(CNS)的重要组成部分,同时又是脑内的主要免疫效应细胞。正常成年人脑中,小胶质细胞处于相对静息状态,而在免疫炎性反应过程中,小胶质细胞显示激活的细胞形态,在向病灶区移行的同时,可以产生神经毒性分子和神经营养因子,具有致炎和抗炎的作用。因此小胶质细胞的双重性对于理解疾病的发生发展,以及寻找疾病的治疗靶点具有极其重要的理论和实际意义。     

胶质细胞与药物成瘾

药物成瘾是一种慢性和复发性脑病.传统的观念认为胶质细胞在药物成瘾中仅起辅助作用.目前发现胶质细胞上存在众多的神经递质受体和转运体,且能分泌多种氨基酸、多肽、神经营养因子及炎症因子,对神经递质的代谢、神经冲动的传导以及突触的调节等起着重要的作用；且胶质细胞在药物成瘾中发生极大变化.对中枢神经系统中的星形胶质细胞、小胶质细...     

神经胶质细胞与HIV相关神经认知障碍

HIV-1相关神经认知障碍(HIV-1 associated neurocognitive disorder,HAND)是艾滋病患者中枢神经系统(central nervous system,CNS)的常见并发症,其患病率高达40%~60%,是40岁以下成人痴呆的最主要原因之一;患者从确诊到死亡的平均时间约为4~6个月,且其发病机理尚待研究.已有的研究表明,HIV-1不感染神经元,但在HAND的发病机制中,神经胶质细胞的过度活化和由此而引发的神经炎症起着重要的作用.本文就神经胶质细胞在HAND的发生发展中的作用进展进行综述.     

神经干细胞移植的研究近况

神经干细胞能够再生和自我更新,并可以分化为神经元、星形胶质细胞和少突胶质细胞,因而神经干细胞移植可用于神经变性、脊髓损伤和神经脱髓鞘等疾病的治疗.本文主要总结了神经干细胞移植在帕金森氏病、脱髓鞘症、脊髓损伤、阿耳茨海默氏病和脑中风治疗中的应用.     

人和小鼠神经干细胞的体外培养的分化研究

首次克隆了小鼠神经元标志性微管蛋白βⅢ基因，从核苷酸序列推导出小鼠与人两者之间在其羧基端有相同的EAQGPK六肽，进一步证实用抗人微管蛋白βⅢ单抗可检测小鼠神经干细胞分化成的神经元细胞，免疫组化鉴定显示小鼠神经干细胞在体积分数为1％胎牛血清（FBS）诱导下，可分化成神经元，星形胶质细胞，少突胶质细胞，同时培养了13周龄胎儿脑来源的人类神经干细胞，用特异性的抗人nestin抗体鉴定，全部为阳性细胞，但它们经诱导分化产生较不同寻常的细胞分化细胞和分化程度，在生长因子减半和1％FBS诱导条件下可分化为神经元和星形胶质细胞，而无少突胶质细胞分化，NF单抗检测证实为早期分化的神经元。     

Caspase signalling controls microglia activation and neurotoxicity

Activation of microglia and inflammation-mediated neurotoxicity are suggested to play a decisive role in the pathogenesis of several neurodegenerative disorders. Activated microglia release pro-inflammatory factors that may be neurotoxic. Here we show that the orderly activation of caspase-8 and caspase-3/7, known executioners of apoptotic cell death, regulate microglia activation through a protein kinase C (PKC)-δ-dependent pathway. We find that stimulation of microglia with various inflammogens activates caspase-8 and caspase-3/7 in microglia without triggering cell death in vitro and in vivo. Knockdown or chemical inhibition of each of these caspases hindered microglia activation and consequently reduced neurotoxicity. We observe that these caspases are activated in microglia in the ventral mesencephalon of Parkinson's disease (PD) and the frontal cortex of individuals with Alzheimer's disease (AD). Taken together, we show that caspase-8 and caspase-3/7 are involved in regulating microglia activation. We conclude that inhibition of these caspases could be neuroprotective by targeting the microglia rather than the neurons themselves.     

雷公藤甲素与雷公藤红素对小胶质细胞炎症反应的影响机制

雷公藤甲素与雷公藤红素是雷公藤的主要生物活性成分，具有多种潜在的药理作用与毒性。神经炎症是各种神经退行性疾病的共同特征，小胶质细胞的激活是中枢神经系统神经炎症的主要组成部分。本文用雷公藤甲素与雷公藤红素处理小胶质细胞（HMO6），探究其对小胶质细胞增殖、细胞膜完整性的影响，以及雷公藤甲素对小胶质细胞M1、M2极化的影响。结果表明：与对照组相比，雷公藤红素（10^-4 mol/L）处理HMO6后，细胞增殖抑制率可高达（71.91±16.28）%（P<0.01，n=3），当浓度为10^-5 mol/L时，乳酸脱氢酶（LDH）释放量明显增加（8.58±1.56）%（P<0.01，n=4）；与对照组相比，雷公藤甲素处理HMO6后，对细胞膜完整性无显著影响，但当浓度为10^-5 mol/L时，细胞增殖抑制率可高达（94.31±0.62）%（P<0.01，n=5），与脂多糖（LPS）组相比，雷公藤甲素浓度为10^-7 mol/L时人肿瘤坏死因子-α（TNF-α）释放量显著减少至（264.83±64.25）pg/mL（P<0.01，n=3），人白细胞介素-10（IL-10）释放量减少至（63.48±16.79）pg/mL（P<0.05，n=3）。     

Mutations in progranulin cause tau-negative frontotemporal dementia linked to chromosome 17

Frontotemporal dementia (FTD) is the second most common cause of dementia in people under the age of 65 years. A large proportion of FTD patients (35-50%) have a family history of dementia, consistent with a strong genetic component to the disease. In 1998, mutations in the gene encoding the microtubule-associated protein tau (MAPT) were shown to cause familial FTD with parkinsonism linked to chromosome 17q21 (FTDP-17). The neuropathology of patients with defined MAPT mutations is characterized by cytoplasmic neurofibrillary inclusions composed of hyperphosphorylated tau. However, in multiple FTD families with significant evidence for linkage to the same region on chromosome 17q21 (D17S1787-D17S806), mutations in MAPT have not been found and the patients consistently lack tau-immunoreactive inclusion pathology. In contrast, these patients have ubiquitin (ub)-immunoreactive neuronal cytoplasmic inclusions and characteristic lentiform ub-immunoreactive neuronal intranuclear inclusions. Here we demonstrate that in these families, FTD is caused by mutations in progranulin (PGRN) that are likely to create null alleles. PGRN is located 1.7 Mb centromeric of MAPT on chromosome 17q21.31 and encodes a 68.5-kDa secreted growth factor involved in the regulation of multiple processes including development, wound repair and inflammation. PGRN has also been strongly linked to tumorigenesis. Moreover, PGRN expression is increased in activated microglia in many neurodegenerative diseases including Creutzfeldt-Jakob disease, motor neuron disease and Alzheimer's disease. Our results identify mutations in PGRN as a cause of neurodegenerative disease and indicate the importance of PGRN function for neuronal survival.     

Apoptosis in the nervous system

Neuronal apoptosis sculpts the developing brain and has a potentially important role in neurodegenerative diseases. The principal molecular components of the apoptosis programme in neurons include Apaf-1 (apoptotic protease-activating factor 1) and proteins of the Bcl-2 and caspase families. Neurotrophins regulate neuronal apoptosis through the action of critical protein kinase cascades, such as the phosphoinositide 3-kinase/Akt and mitogen-activated protein kinase pathways. Similar cell-death-signalling pathways might be activated in neurodegenerative diseases by abnormal protein structures, such as amyloid fibrils in Alzheimer's disease. Elucidation of the cell death machinery in neurons promises to provide multiple points of therapeutic intervention in neurodegenerative diseases.     

Blockade of RAGE-amphoterin signalling suppresses tumour growth and metastases

The receptor for advanced glycation end products (RAGE), a multi-ligand member of the immunoglobulin superfamily of cell surface molecules, interacts with distinct molecules implicated in homeostasis, development and inflammation, and certain diseases such as diabetes and Alzheimer's disease. Engagement of RAGE by a ligand triggers activation of key cell signalling pathways, such as p21ras, MAP kinases, NF-kappaB and cdc42/rac, thereby reprogramming cellular properties. RAGE is a central cell surface receptor for amphoterin, a polypeptide linked to outgrowth of cultured cortical neurons derived from developing brain. Indeed, the co-localization of RAGE and amphoterin at the leading edge of advancing neurites indicated their potential contribution to cellular migration, and in pathologies such as tumour invasion. Here we demonstrate that blockade of RAGE-amphoterin decreased growth and metastases of both implanted tumours and tumours developing spontaneously in susceptible mice. Inhibition of the RAGE-amphoterin interaction suppressed activation of p44/p42, p38 and SAP/JNK MAP kinases; molecular effector mechanisms importantly linked to tumour proliferation, invasion and expression of matrix metalloproteinases.     

Mitochondrial dysfunction and oxidative stress in neurodegenerative diseases

Many lines of evidence suggest that mitochondria have a central role in ageing-related neurodegenerative diseases. Mitochondria are critical regulators of cell death, a key feature of neurodegeneration. Mutations in mitochondrial DNA and oxidative stress both contribute to ageing, which is the greatest risk factor for neurodegenerative diseases. In all major examples of these diseases there is strong evidence that mitochondrial dysfunction occurs early and acts causally in disease pathogenesis. Moreover, an impressive number of disease-specific proteins interact with mitochondria. Thus, therapies targeting basic mitochondrial processes, such as energy metabolism or free-radical generation, or specific interactions of disease-related proteins with mitochondria, hold great promise.     

Pathways to neuronal injury and apoptosis in HIV-associated dementia

Human immunodeficiency virus-1 (HIV-1) can induce dementia with alarming occurrence worldwide. The mechanism remains poorly understood, but discovery in brain of HIV-1-binding sites (chemokine receptors) provides new insights. HIV-1 infects macrophages and microglia, but not neurons, although neurons are injured and die by apoptosis. The predominant pathway to neuronal injury is indirect through release of macrophage, microglial and astrocyte toxins, although direct injury by viral proteins might also contribute. These toxins overstimulate neurons, resulting in the formation of free radicals and excitotoxicity, similar to other neurodegenerative diseases. Recent advances in understanding the signalling pathways mediating these events offer hope for therapeutic intervention.