微孢子虫感染诱导的家蚕细胞凋亡抑制及其Serpins在抑制过程中的作用

项目名称： 微孢子虫感染诱导的家蚕细胞凋亡抑制及其Serpins在抑制过程中的作用

项目编号： No.31470250

项目类型： 面上项目

立项/批准年度： 2015

项目学科： 生物科学

项目作者： 潘国庆

作者单位： 西南大学

项目金额： 80万元

中文摘要： 微孢子虫是一种单细胞、专性细胞内寄生的真菌，可以感染昆虫、线虫等无脊椎动物和人、鱼等脊椎动物。微孢子虫的侵染可以抑制宿主细胞的凋亡，但其抑制凋亡的分子机制还不完全清楚；微孢子虫的哪些基因参与了对凋亡的调控，还未见报道。研究发现痘病毒的丝氨酸蛋白酶抑制物（Serpins）主要参与对宿主细胞凋亡的抑制。有趣的是，我们在家蚕微孢子虫中也发现一簇Serpins（NbSPNs），多数为分泌型，进化分析表明其与痘病毒的Serpin有较近的聚类；其中NbSPN13具有蛋白酶抑制活性，并发现在酿酒酵母中其可以被分选进入线粒体；构建的两株NbSPNs转基因家蚕细胞系具有细胞数目增加较快的特征。我们推测NbSPNs可能参与对宿主细胞凋亡的调控。本课题以上一基金项目结果为基础，旨在阐明微孢子虫诱导家蚕细胞凋亡抑制的分子机制以及NbSPNs在凋亡通路调控中所发挥的作用，这对揭示微孢子虫致病机理具有重要意义。

中文关键词： 微孢子虫；家蚕；丝氨酸蛋白酶抑制物；细胞凋亡；痘病毒

英文摘要： Microsporidia are obligately intracellular and unicellular parasites that classified into Fungi, they cause different infections in invertebrates(insects, nematodes) and vertebrates(human, fish). Infections of microsporidia cause the inhibition of apoptosis of host cell, however the mechanism is still unknown, and also no gene of parasites was reported to participate in the inhibition process. Poxvirus Serpins behave important roles in inhibiting apoptosis of host cells. Fortunately, we characterized a dozen of serpins(NbSPNs) in Nosema bombycis, 10 of them with predicted signal peptides. Phylogeny analysis shows that these serpins clustered together with serpins of poxvirus. NbSPNs could be sorted into yeast mitochondria when expressed in Saccharomyces cerevisae. And the NbSPN13 purified from eukaryote expression has the activity of inhibiting the trypsin. Two NbSPNs transgenic silkworm cell lines both have a trait of quicker increase of cell number than that of control. All these results suggest that NbSPN may participate in apoptosis regulation of host cells as Serpins of poxvirus. So on the basis of results of the last NSFC project, we aim to discover the mechanisms of apoptosis inhibition of silkworm cells induced by the N. bombycis, and to probe the NbSPNs function in regulating the apoptosis of host cell, which is significant for elucidating the pathogenesis of microsporidiosis.

英文关键词： Microsporidia;Silkworm;Serpin;Apoptosis;Poxvirus