血小板衍生生长因子受体β介导吗啡耐受维持状态的分子伴侣机制研究

Chronic morphine tolerance is hard to reverse which became the difficult medical problem in pain therapeutics. It has been reported that the activation of platelet-derived growth factor receptor β (PDGFR-β) play an important role in the maintenance of morphine tolerance. The effects of molecular chaperone expression on translation could switch from facilitating polypeptide elongation to cotranslational folding, which lead to cease of protein synthesis under stress conditions. These may be the downstream mechanism of PDGFR-β activation involved in morphine tolerance. According to these findings, we suppose that repeated administration of morphine could induce the activation of PDGFR-β which may upregulate the expression of molecular chaperones and promote the synthesis of morphine tolerance related effectors and finally lead to the maintenance of morphine tolerance. And administration of PDGFR-β antagonist would swiftly promote the changement of the role of molecular chaperones, which lead to the downregulation of expressions of cytokines and transcriptional factors respectively. In this project, PCR and protein chips will be utilized to screen PDGFR-β related molecular chaperones, transcriptional factors and cytokines, which participate the maintenance of morphine tolerance. The interaction among PDGFR-β activation, molecular chaperones transcriptional factors and cytokines would be investigated to verify the key role of molcular chaperones in maintenance of morphine tolerance. The results of this project may be useful to provide proteomics evidence for the research and development of targeted drugs for morphine tolerance therapy.

难以逆转的吗啡耐受状态是疼痛治疗领域的难题。前期研究显示血小板衍生生长因子受体β（PDGFR-β）参与了吗啡耐受状态的维持。分子伴侣可在翻译过程中发生作用转变，快速中止蛋白质合成，可能介导了PDGFR-β下游的分子机制。本课题据此提出假说：长期应用吗啡可导致PDGFR-β激活，后者通过上调分子伴侣的表达，促进吗啡耐受相关细胞分子和转录因子的合成，导致吗啡耐受状态持续存在；而抑制PDGFR-β激活，将可能使分子伴侣的作用发生转变，通过直接和间接的方式下调最终效应分子的表达至正常水平。本课题拟应用蛋白组学方法筛选大鼠吗啡耐受形成后PDGFR-β相关的分子伴侣和细胞因子、转录因子，建立受体激活与分子伴侣异常表达的相关性，拟合分子伴侣与细胞因子、转录因子的关系，并探讨其蛋白翻译调控过程，最终确定吗啡耐受维持阶段分子伴侣介导的关键性机制，以期为研发治疗吗啡耐受的靶向药物提供蛋白组学依据。

难以逆转的吗啡耐受状态是疼痛治疗领域的难题。本课题组首先构建了大鼠吗啡耐受模型，通过行为学检测研究血小板衍生因子受体抑制剂伊马替尼对吗啡耐受状态的影响，应用免疫荧光的方法确定血小板衍生因子受体发挥作用所在的细胞，应用PCR芯片、蛋白芯片以及生物信息学技术，分析吗啡耐受动物应用伊马替尼前后基因以及蛋白表达的差异变化，筛选出参与血小板衍生因子受体β维持吗啡耐受状态的分子伴侣家族成员，最后应用分子生物学方法，对所筛选的各个分子伴侣家族成员在吗啡耐受维持阶段的作用一一加以鉴定，并初步探讨血小板衍生因子受体β影响各个分子伴侣的机制。我们的研究结果证实血小板衍生因子受体β参与了吗啡耐受维持阶段的分子机制，在此过程中多个与血小板衍生因子受体β相关的分子伴侣被激活，包括Hsp90β、Hspa2、HSP27和BiP等，这些分子伴侣成员分别通过PI3K/AKT、P38信号通路以及内质网应激三条信号通路：IRE1-XBP1、PERK-eIF2α、ATF6参与了吗啡耐受的分子机制。本项目的研究成果为今后研发治疗吗啡耐受的靶向性药物提供了充分的实验依据。