嘌呤受体P2Y13调节小胶质细胞形态、功能及白细胞介素-1β的释放水平

小胶质细胞利用一系列膜受体来感知周围环境。虽然已知P2Y_(12)受体在小胶质细胞的突起向释放ATP/ADP的损伤部位的靶向运动定中起关键作用,但对P2Y_(13)的作用知之甚少。转录组数据表明P2Y_(13)是小胶质细胞中第2高表达的神经递质受体。本研究显示,在缺乏P2Y_(13)受体小鼠的急性脑切片,膜片钳记录由ADP激活P2Y_(12)受体引起的THIK-1 K~+电流密度增加了约50%。这种增加表明P2Y_(12)依赖的趋化性反应增强。但是在P2Y_(13)敲除小鼠,P2Y_(12)介导的小胶质细胞突起向充灌ADP的电极或激光融蚀点聚集所需的时间更长。解剖分析表明,在P2Y_(13)敲除小鼠中,小胶质细胞的密度没有变化,但分枝较少,突起长度较短。因此在基因敲除的小鼠,小胶质细胞趋化的突起必须进一步生长然后才能到达靶标,且脑部监视降低了约30%。在P2Y_(13)敲除小鼠脑片中,阻断P2Y_(12)受体并不会影响监视,表明监视过程不需要这些高亲和力受体的补充激活。令人惊讶的是,在P2Y_(13)敲除小鼠白细胞介素-1β释放的基础值增加了5倍,而LPS和ATP引起的释放不受影响;P2Y_(13)敲除小鼠完整脑中的小胶质细胞未被检测到激活。因此,尽管P2Y_(13)受体与P2Y_(12)非常接近,但它们在调节小胶质细胞形态和功能方面起着不同的作用。     

糖皮质激素对成体海马神经祖细胞的影响

背景：体内研究显示,高浓度糖皮质激素可抑制大鼠内源性神经前体细胞增殖.而神经胶质抗原2蛋白聚糖阳性神经祖细胞（NG2细胞）是成熟中枢神经系统中最大的增殖细胞群体,具有多分化潜能.目的：观察糖皮质激素对体外培养的成熟大鼠海马由来的NG2细胞生存和增殖的影响.方法：原代及传代培养成年大鼠海马NG2细胞,以0,0.1,1,10,100μmol浓度糖皮质激素类药物地塞米松干预48 h后,采用乳酸脱氢酶分析法测定细胞活性,原位缺口末端标记技术（即TUNEL法）观察细胞凋亡情况,5’-溴脱氧尿嘧啶核苷掺入法鉴定细胞增殖状况.结果与结论：1,10,100μmol浓度地塞米松干预明显减少NG2细胞数,并显著增加TUNEL阳性细胞率,明显减少 BrdU 阳性细胞率.结果可见高浓度糖皮质激素能抑制 NG2细胞分裂增殖,并诱导细胞凋亡,从而明显减少NG2细胞数.     

脑蛋白水解物注射液对培养神经胶质抗原2阳性神经祖细胞的影响

背景：脑蛋白水解物注射液能缓解多种神经系统疾病的症状,但其作用机制并不明确。研究显示,脑蛋白水解物注射液在体内和体外实验中有促进神经发生的潜能。目的：观察脑蛋白水解物注射液对培养的神经胶质抗原2阳性神经祖细胞增殖和分化的影响。方法：取成年大鼠海马原代及传代培养神经胶质抗原2细胞,以免疫荧光染色法鉴定细胞性质,以乳酸脱氢酶分析法测定细胞活性,以原位缺口末端标记技术（即TUNEL法）观察细胞凋亡,BrdU掺入法鉴定新生细胞。结果与结论：脑蛋白水解物注射液干预显著减少TUNEL阳性细胞数,并明显增加神经胶质抗原2细胞数和神经胶质抗原2细胞中微管相关蛋白2a＋2b、突触蛋白I、y-氨基丁酸和囊泡 y-氨基丁酸转运体表达水平。说明脑蛋白水解物注射液能抑制神经胶质抗原2细胞凋亡,促进神经胶质抗原2细胞增殖,并能促进神经胶质抗原2细胞向神经元（特别是y-氨基丁酸能抑制性中间神经元）分化。     

自体富血小板血浆对人骨髓来源内皮祖细胞功能活性的影响

背景:富血小板血浆是经过特殊方法提取的血小板含量丰富的血浆,相较普通血清含有更丰富的细胞因子,如血小板衍生因子、转化生长因子β、血管内皮生长因子等.目的:观察富血小板血浆对人骨髓血来源的内皮祖细胞生物学特性的影响,拟探讨富血小板血浆在骨创伤修复血管化中的作用.方法:抽取16名健康志愿者自体外周静脉血获取富血小板血浆.采用密度梯度离心法获取骨髓血内皮祖细胞,将培养8 d的内皮祖细胞随机分为对照组和富血小板血浆组,胎牛血清组采用培养基为体积分数为10%胎牛血清配比高糖DMEM培养基加青霉素、链霉素各100 U/mL;无血清对照组采用高糖DMEM培养基加青霉素、链霉素各100 U/mL.相差显微镜观察细胞生长情况,激光共聚焦显微镜鉴定,AC133和vWF双染阳性细胞为正在分化的内皮祖细胞,MTT法检测细胞培养6,12,48 h增殖情况,Transwell小室检测迁移,Matrigel管腔形成实验检测管腔形成能力.结果与结论:①各组细胞均在接种后12～24 h开始贴壁,并由圆形逐步变化为梭型、多角形、不规则形状等.②富血小板血浆作用于内皮祖细胞6 h后,A490值明显高于对照组(P＜0.05);12 h时其促进作用更强(P＜0.01).在0～48 h,随时间延长,富血小板血浆促进内皮祖细胞增殖的作用相应增强.③富血小板血浆可提高内皮祖细胞的迁移能力,6 h开始明显增强(P＜0.05),于12 h达高峰(P＜0.01).48 h有所下降,但仍明显高于对照组(P＜0.01).④富血小板血浆显著增强内皮祖细胞体外管腔形成能力,在作用时间为48 h最为显著,并且形成的管腔样结构也较对照组复杂.     

大鼠背根神经节P2Y1与P2Y4嘌呤受体的表达比较

目的:探讨P2Y1和P2Y4亚基在大鼠背根神经节(D R G)神经元的表达。方法:应用组织水平和多细胞水平R T-PC R方法从不同角度检测了P2Y1和P2Y4受体的表达情况。结果:两种R T-PC R扩增结果均显示:P2Y1亚型有特异性表达阳性条带出现,而P2Y4亚型则无特异性表达条带出现。结论:大鼠D R G的大、中、小细胞中均有P2Y1亚型表达,而无P2Y4亚型的表达。     

氯胺酮对神经病理性疼痛大鼠脊髓P2X_4受体mRNA表达的影响

目的:研究氯胺酮对神经病理性疼痛大鼠脊髓P2X_4受体mRNA表达的影响.方法:雄性SD大鼠45只,体重180～220g,随机分为假手术组(S组)、对照组(C组)和氯胺酮Ⅰ、Ⅱ、Ⅲ组(KⅠ、Ⅱ、Ⅲ组),每组9只.S组大鼠仅分离坐骨神经但不结扎,其余组建立坐骨神经慢性压迫性损伤(CCI)模型,K Ⅰ、Ⅱ、Ⅲ组分别于CCI后3d开始至取材点每天腹腔注射氯胺酮5mg/kg、10mg/kg、20mg/kg;S组和C组注射相同体积的生理盐水.各组大鼠分别于术前1d,术后3d、7d、14d、21d测定大鼠机械性痛觉过敏(MWT)和热痛觉过敏(TWL).各组均分别于CCI术后7d、14d、21d取3只大鼠,测定痛阈后处死,取L_(4～5)脊髓组织,用逆转录PCR(RT-PCR)方法测定P2X_4受体mRNA表达水平.结果:与术前及S组比较,C组、K Ⅰ、Ⅱ、Ⅲ组术后3d开始热痛阈及机械痛阈显著降低(P＜0.05).与C组比较,K Ⅰ、Ⅱ、Ⅲ组术后7d,14d,21d热痛阈及机械痛阈显著升高(P＜0.05).与S组比较,C组、K Ⅰ、Ⅱ、Ⅲ组大鼠脊髓P2X_4受体表达在术后7d、14d、21d均显著增加(P＜0.05);与C组大鼠比较,K Ⅰ、Ⅱ、Ⅲ组脊髓P2X_4受体表达明显减少(P＜0.05).结论:腹腔注射氯胺酮可抑制慢性神经痛大鼠痛觉过敏,该作用可能是通过作用于P2X_4受体介导的.     

受体相互作用蛋白-3分子功能及其在神经疾病中的研究进展

细胞死亡一直以来被简单分为凋亡和坏死两种主要形式,其中坏死被公认为是组织细胞受到损害因素下发生的被动、不可逆、非调控性的死亡过程。然而最新的研究证实,在某些特定条件下坏死仍可受到调控并具有被逆转的可能,这种新型细胞死亡方式被称为程序性坏死。程序性坏死途径参与了生物体的生长发育、衰老和死亡等生理学进程,尤其在多种神经系统疾病(颅脑创伤、感染、神经退行性病变)的发生、发展中扮演了重要角色。受体相互作用蛋白-3(RIP3)作为细胞凋亡和坏死之间相互转换的关键性分子,在介导神经细胞损伤的程序性坏死、NF-κB通路激活以及诱发线粒体活性氧自由基(ROS)的生成等机制中发挥着重要作用。本文就RIP3的分子功能及其与神经疾病的关系进展予以综述。     

50Hz电磁场促进骨髓源神经祖细胞向神经元分化作用的研究

目的:通过分析50Hz电磁场干预骨髓源神经祖细胞向神经细胞分化前后相关神经细胞标志物m RNA表达水平,探讨低频电磁场对骨髓源神经祖细胞诱导分化的作用。方法:利用全骨髓培养法获取骨髓间充质干细胞,将第2代骨髓间充质干细胞在无血清神经干细胞培养环境中悬浮诱导,获取骨髓源神经祖细胞。将第3代骨髓源神经祖细胞分为2组贴壁培养:电磁场组与对照组。电磁场组干预方法为正弦波磁场、频率50Hz、强度5m T,60min/d,共15天,对照组置于无磁场干预的同等环境中。骨髓源神经祖细胞诱导后,采用免疫细胞荧光检测巢蛋白(Nestin)与微管蛋白抗体(Tuj-1)的表达变化;采用实时定量基因扩增荧光检测系统(Q-PCR)检测Nestin,唾液酸-神经细胞粘附分子(PSA-NCAM)和β-微管蛋白-Ⅲ(β-Ⅲtubulin),乙酰胆碱酯酶(ACHE),5-羟色胺(5-HT),γ-氨基丁酸(GABA)m RNA表达水平变化。结果:骨髓间充质干细胞在无血清神经干细胞培养环境中可形成骨髓源神经祖细胞,表达Nestin阳性产物;两组诱导后的神经元样细胞免疫细胞荧光检测Tuj-1均呈阳性表达,Q-PCR结果示Nestin,PSA-NCAM,β-Ⅲtubulin,ACHE,5-HT,GABA m RNA表达水平与诱导前比较显著下降(P0.01),电磁场组β-Ⅲtubulin m RNA表达水平显著高于对照组(P0.05)。结论:50Hz电磁场可以促进骨髓源神经祖细胞向神经元分化。     

P2X受体与膀胱功能障碍相关疾病的研究进展

P2X受体介导的信号转导在调控正常及病理状态下的膀胱均起到重要的作用,其具体的内在机制还未完全阐明。在膀胱收缩及充盈的过程中,P2X 受体充当关键角色,因此对该受体的研究已成为当前的热点,现将P2X受体与膀胱功能障碍相关疾病的研究进展予以综述。     

In vivo magnetic resonance imaging tracks adult neural progenitor cell targeting of brain tumor

Using magnetic resonance imaging (MRI), we described a method for noninvasively tracking grafted neural progenitor cells and bone marrow stromal cells (MSCs) in brain tumor of the rat. Neural progenitor cells and MSCs were labeled with lipophilic dye-coated superparamagnetic particles. The labeled neural progenitor cells and MSCs were transplanted to rats via the cisterna magna and a tail vein, respectively, 1 week after 9L-gliosarcoma cell implantation. Three-dimensional (3D) gradient echo and contrast agent images revealed dynamic migration of adult neural progenitor cells and MSCs detected by loss of MRI signals towards tumor mass and infiltrated tumor cells. Prussian blue staining and fluorescent microscope analysis showed that grafted cells targeted tumor cells and areas with grafted cells corresponded to areas with loss of MRI signals. These results demonstrate that the MRI technique provides a sensitive method for in vivo assessment of grafted cells targeting tumor mass and infiltrated tumor cells and that adult neural progenitor cells and MSCs can target tumor aggregates in the brain.     

Regulation of T cell receptor signaling by activation-induced zinc influx

Zinc is a trace element that is essential for innate and adaptive immune responses. In addition to being a structural element of many proteins, zinc also functions as a neurotransmitter and an intracellular messenger. Temporal or spatial changes in bioavailable zinc may influence the activity of several enzymes, including kinases and phosphatases. We provide evidence that zinc functions as an ionic signaling molecule after T cell activation. Cytoplasmic zinc concentrations increased within 1 min after T cell receptor (TCR) triggering, in particular in the subsynaptic compartment. The increase depended on the extracellular zinc concentrations and was inhibited by silencing zinc transporter Zip6. Increased zinc influx reduced the recruitment of SHP-1 to the TCR activation complex, augmented ZAP70 phosphorylation and sustained calcium influx. By calibrating TCR activation thresholds, increased extracellular zinc bioavailability facilitated the induction of T cell proliferative responses to suboptimal stimuli.     

In vivo tracking of neural progenitor cell migration to glioblastomas

The ability to noninvasively track the migration, engraftment, and proliferation of neural progenitor cells (NPCs) has significant clinical and research implications. The purpose of our study was to explore the macroscopic migratory capabilities of NPCs toward brain tumors after implantation into nude mice. We stably transfected C17.2 NPCs with the firefly luciferase gene (F-luc) and implanted cells into (1) the contralateral brain parenchyma (2 x 10(6) cells), (2) the ventricles (2 x 10(6) cells), (3) the vasculature (1 x 10(5) cells), or (4) the intraperitoneal cavity (5 x 10(6) cells) of mice bearing intracranial gliomas (Gli36). Using serial bioluminescence imaging, migration of parenchymally injected cells was observed across the corpus callosum, first detected at 1 week, with maximal density at the tumor site 2-3 weeks after implantation. Similar patterns were also observed with intraventricular injections; however, tumors were populated earlier, presumably because of the shorter distance to travel. Intravenous injections resulted in more modest tumoral NPC populations, whereas virtually no cells could be identified in tumors after intraperitoneal injection. These results confirm the migratory capability of NPCs over considerable distances and their preferential accumulation in brain tumors on CNS rather than peripheral injection.     

Regulation of macrophage functions by L-arginine

Sites of inflammation with prominent macrophage infiltration, such as wounds and certain tumors, are uniquely deficient in free arginine. The effects of arginine availability on macrophage physiology were investigated. When cultured in media containing less than 0.1 mM L-arginine, rat resident peritoneal macrophages exhibited enhanced spreading, tumor cytotoxicity, superoxide production, phagocytosis, and protein synthesis. Thus, arginine concentrations similar to those found in sites of inflammation can augment macrophage functions, while those found in plasma (approximately 0.1 mM) and in commonly used culture media (0.4 to 1.2 mM) are inhibitory. Culture in homoarginine, but not D-arginine, ornithine, citrulline, urea, histidine, or lysine also inhibited macrophage tumor cytotoxicity, indicating the specificity of the effect. In contrast to resident macrophages, the tumor cytotoxicity of peritoneal macrophages obtained after C. parvum injection was suppressed by culture in arginine-deficient media. However, L-arginine-deficient media enhanced all other activation-associated functions in C. parvum-elicited macrophages as in resident cells. Arginine-free wound fluid promoted resident macrophage tumoricidal activity when compared with rat serum, and again, the addition of L-arginine was inhibitory. The marked effects of L-arginine availability on macrophage functions, together with the knowledge that these cells modify the extracellular arginine concentration in sites of inflammation through arginase, provide evidence for an autoregulatory mechanism of macrophage activation.     

慢性压迫性脊髓损伤后神经前体细胞的增殖

背景：关于成年哺乳类动物脊髓损伤后神经前体细胞的增殖特征和来源以及星形胶质细胞在其中的作用尚无肯定性结论。目的：通过分析成年大鼠慢性压迫性脊髓损伤及减压后巢蛋白和胶质纤维酸性蛋白表达的变化，探讨神经前体细胞的增殖特征和来源以及星形胶质细胞在其中的作用。设计：完全随机对照实验。单位：兰州大学第二医院骨科研究所。材料：实验于2003-03／10在兰州大学第二医院骨科研究所完成，选择成年健康Wistar大鼠50只。随机分为正常对照组、慢性压迫性脊髓损伤中度组（压迫物占椎管矢状径的40％）、重度组（压迫物占椎管矢状径的60％）及重度压迫损伤24h后减压3d、10d组，每组10只。主要观察指标：①各组大鼠压迫临近段（距压迫边缘至5mm）脊髓灰质和白质内nestin的阳性表达并测量其灰度值。②各组大鼠脊髓内胶质纤维酸性蛋白的表达。结果：50只大鼠均进入实验分析。①中度压迫组（白质235.33&;#177;6.48，灰质196．28&;#177;6．55）、重度压迫组（白质190．45&;#177;4．91，灰质173．15&;#177;5．98）及重度压迫损伤减压后3d组（白质198．39&;#177;3．24，灰质180．38&;#177;4．51）和减压后10d组白质（202．55&;#177;3．54）中巢蛋白均有明显表达（P〈0．05），以重度压迫组最为显著（P〈0．01）。减压10d组的灰质和脊髓中央管室管膜细胞的巢蛋白表达与正常对照组相比，差异无显著性意义（P〉0．05）。②与正常对照组相比，各损伤组脊髓内胶质纤维酸性蛋白表达增强，胶质纤维酸性蛋白阳性细胞数目增多、胞体肥大，突起增粗、增长。结论：成年大鼠慢性压迫性脊髓损伤及减压后早期存在神经前体细胞的增殖。星形胶质细胞参与神经前体细胞的增殖与迁移，对脊髓具有重要的营养修复作用。     

慢性压迫性脊髓损伤后神经前体细胞的增殖

背景:关于成年哺乳类动物脊髓损伤后神经前体细胞的增殖特征和来源以及星形胶质细胞在其中的作用尚无肯定性结论。目的:通过分析成年大鼠慢性压迫性脊髓损伤及减压后巢蛋白和胶质纤维酸性蛋白表达的变化,探讨神经前体细胞的增殖特征和来源以及星形胶质细胞在其中的作用。设计:完全随机对照实验。单位:兰州大学第二医院骨科研究所。材料:实验于2003-03/10在兰州大学第二医院骨科研究所完成,选择成年健康Wistar大鼠50只。随机分为正常对照组、慢性压迫性脊髓损伤中度组(压迫物占椎管矢状径的40%)、重度组(压迫物占椎管矢状径的60%)及重度压迫损伤24h后减压3d、10d组,每组10只。主要观察指标:①各组大鼠压迫临近段(距压迫边缘至5mm)脊髓灰质和白质内nestin的阳性表达并测量其灰度值。②各组大鼠脊髓内胶质纤维酸性蛋白的表达。结果:50只大鼠均进入实验分析。①中度压迫组(白质235.33±6.48,灰质196.28±6.55)、重度压迫组(白质190.45±4.91,灰质173.15±5.98)及重度压迫损伤减压后3d组(白质198.39±3.24,灰质180.38±4.51)和减压后10d组白质(202.55±3.54)中巢蛋白均有明显表达(P<0.05),以重度压迫组最为显著(P<0.01)。减压10d组的灰质和脊髓中央管室管膜细胞的巢蛋白表达与正常对照组相比,差异无显著性意义(P>0.05)。②与正常对照组相比,各损伤组脊髓内胶质纤维酸性蛋白表达增强,胶质纤维酸性蛋白阳性细胞数目增多、胞体肥大,突起增粗、增长。结论:成年大鼠慢性压迫性脊髓损伤及减压后早期存在神经前体细胞的增殖。星形胶质细胞参与神经前体细胞的增殖与迁移,对脊髓具有重要的营养修复作用。     

MRI detects white matter reorganization after neural progenitor cell treatment of stroke

We evaluated the effects of neural progenitor cell treatment of stroke on white matter reorganization using MRI. Male Wistar rats (n = 26) were subjected to 3 h of middle cerebral artery occlusion and were treated with neural progenitor cells (n = 17) or without treatment (n = 9) and were sacrificed at 5-7 weeks thereafter. MRI measurements revealed that grafted neural progenitor cells selectively migrated towards the ischemic boundary regions. White matter reorganization, confirmed histologically, was coincident with increases of fractional anisotropy (FA, P < 0.01) after stroke in the ischemic recovery regions compared to that in the ischemic core region in both treated and control groups. Immunoreactive staining showed axonal projections emanating from neurons and extruding from the corpus callosum into the ipsilateral striatum bounding the lesion areas after stroke. Fiber tracking (FT) maps derived from diffusion tensor imaging revealed similar orientation patterns to the immunohistological results. Complementary measurements in stroke patients indicated that FT maps exhibit an overall orientation parallel to the lesion boundary. Our data demonstrate that FA and FT identify and characterize cerebral tissue undergoing white matter reorganization after stroke and treatment with neural progenitor cells.     

Regulation of bone mass by Wnt signaling

Wnt proteins are a family of secreted proteins that regulate many aspects of cell growth, differentiation, function, and death. Considerable progress has been made in our understanding of the molecular links between Wnt signaling and bone development and remodeling since initial reports that mutations in the Wnt coreceptor low-density lipoprotein receptor-related protein 5 (LRP5) are causally linked to alterations in human bone mass. Of the pathways activated by Wnts, it is signaling through the canonical (i.e., Wnt/beta-catenin) pathway that increases bone mass through a number of mechanisms including renewal of stem cells, stimulation of preosteoblast replication, induction of osteoblastogenesis, and inhibition of osteoblast and osteocyte apoptosis. This pathway is an enticing target for developing drugs to battle skeletal diseases as Wnt/beta-catenin signaling is composed of a series of molecular interactions that offer potential places for pharmacological intervention. In considering opportunities for anabolic drug discovery in this area, one must consider multiple factors, including (a) the roles of Wnt signaling for development, remodeling, and pathology of bone; (b) how pharmacological interventions that target this pathway may specifically treat osteoporosis and other aspects of skeletal health; and (c) whether the targets within this pathway are amenable to drug intervention. In this Review we discuss the current understanding of this pathway in terms of bone biology and assess whether targeting this pathway might yield novel therapeutics to treat typical bone disorders.