P2X7受体与疾病的相关性

P2X受体是一类离子型配体门控通道,分为7个不同的亚型(P2X1～7)。嘌呤能离子通道型受体7(purinergic ligand-gated ion channel 7 receptor, P2X7R)是ATP门控的,非选择性的阳离子通道,属于嘌呤受体P2X家族。P2X7受体广泛表达于神经系统、肌肉组织和免疫系统。在胞外ATP作用下,P2X7受体偶联多种胞内信号通路,参与细胞增殖、凋亡及炎症因子的释放等多种生理功能。研究发现,P2X7受体与诸多疾病有着密切联系,包括自身免疫性疾病(如关节炎和炎症性肠病)、神经退行性疾病、慢性疼痛、情绪障碍和癌症等。P2X7受体异常表达会导致这些疾病的发生,增加疾病的易感性与病变程度。现就P2X7受体的生物学特征、P2X7受体与疾病的关系及其特异性阻断剂和激动剂进行综述。     

P2X7受体短肽单克隆抗体的制备及鉴定

旨在制备与鉴定鼠抗P2X7受体的蛋白单克隆抗体.以人P2X7受体的胞外段制备短肽作为抗原,皮下注射免疫Balb/c小鼠.分离小鼠脾脏B淋巴细胞与骨髓瘤细胞融合并培养,挑选阳性杂交瘤细胞,扩大培养,制备和鉴定P2X7其生物学效应.结果显示,获得1株稳定分泌抗人P2X7受体的单克隆抗体的杂交瘤细胞株,所分泌的单抗类型重链为IgG1,轻链为κ;该株杂交瘤细胞腹水效价为1∶6.4×104;传30代及液氮中保存6个月,抗体效价稳定;Western blotting检测证明该单抗与人细胞表面的P2X7受体蛋白特异地结合.所制备的抗人P2X7受体的单克隆抗体具有高度的特异性及稳定性,为针对P2X7受体为靶点的抗体药物的开发应用、疾病的辅助诊断奠定了基础.     

P2X7受体与炎性细胞因子

P2X7受体是嘌呤受体中功能独特的一个亚型,为ATP控制的离子通道,在单核细胞、巨噬细胞、中性粒细胞中高表达,被ATP激活后导致K＋外流和Ca^2＋内流、非选择性膜孔形成,启动一系列信号途径如炎症小体NALP3的活化,丝裂原蛋白激酶途径激活NF-κB增强炎性细胞因子转录,ROS和氮介质的产生,介导IL-1β、IL-6、IL-18、TNF-α、MIP-2、CCL2、HMGB1等多种炎性细胞因子的释放,参与炎症的发生发展,与真菌感染及阿尔茨海默病、类风湿性关节炎、哮喘等炎症性疾病密切相关.     

P2X7受体敲除对小鼠骨癌痛的影响北大核心CSCD

癌痛是临床晚期恶性肿瘤患者常见的临床表现之一。其中,以肺癌、乳腺癌和前列腺癌等骨转移引起疼痛尤为严重。P2X7受体是ATP门控离子通道型嘌呤能受体的一个亚型,在脊髓背角主要表达在胶质细胞。P2X7受体激活可以促进胶质细胞释放多种炎症介质,介导脊髓中枢敏化。该受体在炎症痛及神经病理性疼痛中的作用已多有报道,但在癌痛中的作用尚有争议。本研究采用C57BL/6J小鼠股骨骨髓腔内接种Lewis肺癌细胞所诱导的骨癌痛小鼠模型,分析对比了野生型小鼠和P2X7受体基因敲除(P2rx7-/-)小鼠骨癌痛的发生、发展。野生型C57BL/6J小鼠股骨骨髓腔内接种Lewis肺癌细胞后,患侧后肢分别在第7和14天开始出现明显的触诱发痛和热痛过敏,并呈进行性加重;Cat Walk步态分析显示骨癌第21和28天,小鼠患侧脚印面积明显减小,站立时相持续时间缩短,举步时相持续时间显著延长;组织病理学结果显示受累骨骨髓腔有大量肿瘤细胞浸润,骨髓质正常结构消失,伴有髓质骨和皮质骨的破坏。与研究设计时的预期相反,P2rx7-/-小鼠接种瘤细胞后,患肢痛行为检测结果与野生型小鼠相似,甚至在Cat Walk步态分析检测值变化发生的时间上较野生小鼠有所提前。这与本研究组前期在大鼠骨癌痛模型观察到的阻断P2X7受体明显对抗骨癌痛的结果完全不同,提示P2X7受体在大、小鼠骨癌痛中可能发挥不同的作用,并再次提示疾病动物模型上的研究结果与人类疾病机理之间还存在巨大差异。     

中枢神经系统离子通道受体P2X7的研究进展

在ATP门控离子通道P2X受体家族中,P2X7受体由于在结构和功能上与其他(P2X1-P2X6)受体的显著差别而备受关注.P2X7受体是由3个同源亚基组成的多聚体,其C端为P2X受体家族中最长的,与其他已知蛋白没有同源性.P2X7受体具有独特的双功能性,被ATP激活后形成非选择性阳离子通道,允许钾、钠、钙等阳离子跨膜流动,而对二价阳离子表现出相对较强的选择性,在低浓度二价阳离子环境及ATP的持续刺激下,激活的P2X7受体能形成大的孔通道.P2X7受体广泛分布在血液系统、免疫系统和骨组织等多种组织器官中,通过信号转导参与细胞增殖、蛋白合成和细胞凋亡等事件.近年来在中枢神经系统中的研究发现,P2X7受体参与神经突触传递等生理过程,并在神经性退变等病理过程中发挥重要的调节作用.其中,多种假说支持它与少突胶质细胞的损伤有密切关系.     

P2X受体在CCI模型中介导疼痛的研究进展

神经病理痛是临床上常见病症,对人身心健康危害较大,其发病机制尚不清楚,目前无有效的治疗手段,加之慢性神经病理痛持续时间长,其研究成为疼痛领域的热点和重点.本文将围绕着P2X受体在CCI模型中介导疼痛方面的研究加以归纳和总结.     

P2X7受体与炎症性肠病北大核心CSCD

P2X7受体与炎症密切相关,且在肠道细胞广泛表达。动物实验表明,ATP/P2X7信号主要介导加重肠炎,众多细胞参与这一作用,包括巨噬细胞、树突状细胞、T细胞、肥大细胞以及肠道神经元等。也有证据表明在弓形虫引起的肠炎中,P2X7信号则发挥抑制炎症的作用,其具体机制还有待进一步研究。本文就P2X7受体与炎症性肠病(inflammatory bowel disease,IBD)的相关研究进展作一综述,希望能为P2X7受体与IBD的进一步研究提供指导和借鉴。     

克隆的P2受体亚型的药理学研究进展

细胞外嘌呤（腺苷,ADP,ATP）及嘧啶（UDP,UTP）为重要的信使分子,通过细胞表面P2受体介导产生不同的生物效应,P2嘌吟受体的概念于1978年被提出,随后根据药理学特征又被分为P2X及P2X嘌呤受体,90年代,采用分子生物学手段,一系列配体门控的P2X受体及G蛋白耦联的P2Y受体被克隆及功能表达,迄今为止,已有七型P2X受体亚型（P2X1－7）及六型P2Y受体亚型被克隆（P2Y1,2,4,6,11,12）,各型具有不同的分子结构,药理学特征及组织分布,本文还讨论了目前可用于区分各亚型激动剂及拮抗剂。     

不同诱导因子对人外周血单个核细胞P2X7受体表达的作用

ATP激活P2X7受体可产生一系列的白细胞功能反应,因此P2X7受体的表达调控引起我们的兴趣。然而P2X7受体在正常人外周血单个核细胞(peripheral blood mononuclear cells,PBMC)、单核细胞中的表达调控机制尚未阐明。本文用半定量RT-PCR方法检测多种细胞因子、细菌抗原、丝裂原对P2X7受体表达的诱导作用,探索P2X7受体的诱导表达模式。结果表明,单个核细胞和单核细胞可检出P2X7受体的表达;白细胞介素2、4、6(interleukin-2、-4、-6,IL-2、IL-4、IL-6)、肿瘤坏死因子仪(tumour necrosis factor-α,TNF-α)等细胞因子和金黄色葡萄球菌CowanⅠ株(Staphylococcus aureus Cowan strainⅠ,SAC)、脂多糖(lipopolysaccharide,LPS)能上调PBMC的P2X7受体表达,而γ干扰素(interferon-γ,IFN-γ)、粒-巨噬细胞集落刺激因子(granulocyte-macrophage colony-stimulating factor,GM-CSF)、巨噬细胞集落刺激因子(macmphage colony-stimulating factor,M-CSF)和植物血凝素(phytohemagglutinin-M,PHA-M)等则没有作用;LPS和M-CSF可以提高单核细胞的P2X7受体表达,IFN-γ、TNF-α、GM-CSF作用较弱,但是这些因子的预处理并不能增强LPS对P2X7受体表达的诱导。炎症因子促进P2X7受体的表达,提示P2X7受体可能在对抗细菌感染的免疫反应中起一定作用,这有待于进一步研究。     

缓激肽B1受体与疼痛

摘要：缓激肽B1受体（bradykinin 1 receptors,B1Rs）是与Gq蛋白相偶联的受体。正常状态下,B1R除了在神经系统中（如脊髓背角浅层和感觉神经节）有少数表达外,其他机体组织中几乎不存在。在炎症或者神经受损的情况下,脊髓背角浅层和感觉神经节B1R表达量大大上升,参与炎性疼痛和神经病理性疼痛的产生和维持。近年来的研究表明,B1R在糖尿病性神经病理疼痛的发病中起着重要的作用。阻断B1R能有效抑制糖尿病诱发的热痛觉过敏和冷觉及触觉超敏。此外,B1R和癌症痛的发生也有密切关系,所以,对B1R的研究可能会为治疗这些临床顽症提供新的靶点。关键词：缓激肽B1受体;炎性痛;神经病理性痛中图分类号：Q189;Q42;R338文献标志码：A     

P2X receptors-mediated cytosolic phospholipase A2 activation in primary afferent sensory neurons contributes to neuropathic pain

Activation of P2X₃ and P2X_2/3 receptors (P2X₃R/P2X_2/3R), ionotropic ATP receptor subtypes, in primary sensory neurons is involved in neuropathic pain, a debilitating chronic pain that occurs after peripheral nerve injury. However, the underlying mechanisms remain unknown. We investigated the role of cytosolic phospholipase A₂ (cPLA₂) as a downstream molecule that mediates the P2X₃R/P2X_2/3R-dependent neuropathic pain. We found that applying ATP to cultured dorsal root ganglion (DRG) neurons increased the level of Ser505-phosphorylated cPLA₂ and caused translocation of Ser505-phosphorylated cPLA₂ to the plasma membrane. The ATP-induced cPLA₂ activation was inhibited by a selective antagonist of P2X₃R/P2X_2/3R and by a selective inhibitor of cPLA₂. In the DRG in vivo , the number of cPLA₂-activated neurons was strikingly increased after peripheral nerve injury but not after peripheral inflammation produced by complete Freund's adjuvant. Pharmacological blockade of P2X₃R/P2X_2/3R reversed the nerve injury-induced cPLA₂ activation in DRG neurons. Moreover, administering the cPLA₂ inhibitor near the DRG suppressed nerve injury-induced tactile allodynia, a hallmark of neuropathic pain. Our results suggest that P2X₃R/P2X_2/3R-dependent cPLA₂ activity in primary sensory neurons is a key event in neuropathic pain and that cPLA₂ might be a potential target for treating neuropathic pain.     

New insights into protease-activated receptor 4 signaling pathways in the pathogenesis of inflammation and neuropathic pain: a literature review

Pain is an unpleasant sensory and emotional experience that is commonly associated with actual or potential tissue damage. Despite decades of pain research, many patients continue to suffer from chronic pain that is refractory to current treatments. Accumulating evidence has indicated an important role of protease-activated receptor 4 (PAR4) in the pathogenesis of inflammation and neuropathic pain. Here we reviewed PAR4 expression and activation via intracellular signaling pathways and the role of PAR4 signaling pathways in the development and maintenance of pain. Understanding PAR4 and its corresponding signaling pathways will provide insight to further explore the molecular basis of pain, which will also help to identify new targets for pharmacological intervention for pain relief.     

Kinetics of ATP release following compression injury of a peripheral nerve trunk

Compression and/or contusion of a peripheral nerve trunk can result in painful sensations. It is possible that release of ATP into the extracellular space may contribute to this symptom. In the present study, we used real-time measurements of ATP-induced bioluminescence together with electrophysiological recordings of compound action potentials to follow changes in the extracellular ATP concentration of isolated rat spinal roots exposed to mechanical stimuli. Nerve compression for about 8 s resulted in an immediate release of ATP into the extracellular space and in a decrease in the amplitude of compound action potentials. On average, a rise in ATP to 60 nM was observed when nerve compression blocked 50% of the myelinated axons. After the compression, the extracellular concentration of ATP returned to the resting level within a few minutes. The importance of ecto-nucleotidases for the recovery period was determined by exposure of isolated spinal roots to high concentrations of ATP and by use of inhibitors of ecto-nucleotidases. It was observed that spinal roots have a high capacity for ATP hydrolysis which is only partially blocked by βγ-methylene ATP and ARL 67156. In conclusion, acute nerve compression produces an increase in the extracellular concentration of ATP and of its metabolites which may be sufficient for activation of purinergic P2 and/or P1 receptors on axons of nociceptive afferent neurons.