【作者】 张进；

【导师】 路群；

【作者基本信息】 云南大学 ， 生物工程， 2022， 硕士

【摘要】 自噬是一个在进化上高度保守的细胞过程,它能对包裹在内的内容物进行降解。在过去的二十年中,已被证明自噬的紊乱与许多人类疾病的发生发展有关,例如癌症、代谢紊乱、衰老、感染疾病、炎症等。Epg5最先在线虫中发现,是一个重要的自噬基因,在自噬底物的降解中发挥重要的作用。Epg5-/-小鼠表现出高于基础水平的肺部炎症,对致命性流感病毒的感染具有抗性。诺如病毒(Norovirus,No V)是全球流行性急性肠胃炎的主要病因,在儿童、老年人和免疫功能低下者中发病率和死亡率较高,对人类生命健康及财产造成了很大的负担。由于我们对No V的发病机制了解不完全,至今也没有有效的抗病毒治疗手段或者疫苗。最近,我们发现Epg5-/-小鼠对持续性诺如病毒(MNV.CR6)的感染具有抗性,这一发现尚未见报道。本文研究发现Epg5-/-小鼠表现出对诺如病毒持续性感染的抵抗性这一现象,并阐明了此现象的相关机制。研究表明:在小鼠水平上,(1)与野生型小鼠相比,Epg5-/-小鼠肠道中病毒的靶细胞——簇细胞(tuft cell)的数量以及定位是没有显著差异的;(2)但是Epg5-/-小鼠表现出干扰素相关通路的基因上调,与野生型小鼠相比,Epg5-/-小鼠干扰素刺激基因以及部分干扰素基因的表达上调。在细胞水平上,(3)病毒在Epg5敲除的细胞中的复制与对照组相比是没有显著差异的;(4)但是Epg5敲除的细胞中病毒的非结构蛋白NS1的分泌受阻,而非结构蛋白NS1的分泌是病毒感染细胞以及持续性感染所必需的。综上所述,本研究揭示了自噬基因Epg5的缺乏通过上调干扰素基因和干扰素相关基因的表达,以及阻碍病毒非结构蛋白NS1的分泌进而对诺如病毒的持续性感染产生了一定的抵抗性。这一研究结果为诺如病毒的治疗以及疫苗的开发提供了一些新思路。更多还原

【Abstract】 Autophagy is an evolutionarily conserved cellular process in which cytoplasmic contents are degraded within the lysosome.In the past twenty years,studies have been showed that deregulation of autophagy has been linked to the development of numerous human diseases such as cancer,metabolism disorder,aging,infection diseases,inflammation,and so on.Epg5 was first identified in C.elegans as an essential autophagy gene which functions in autophagic substrate degradation.Epg5 deficient mice exhibited evaluated baseline lung inflammation and were resistant to lethal influenza virus infection.Norovirus(Nov)is the leading cause of epidemic acute gastroenteritis globally,especially causing high morbidity and mortality in children,the elderly and immunocompromised individuals.Currently,there are no licensed antiviral treatments or vaccines due in part to our incomplete understanding of Norovirus pathogenesis.Recently,we surprisingly found that Epg5-/-mice are resistant to infection by persistent murine norovirus(MNV.CR6)which has not been reported.In this paper,it was found that Epg5-/-mice showed resistance to persistent infection with norovirus and elucidated the relevant mechanisms of this phenomenon.Studies have shown that at the mouse level,(1)Compared with wild-type mice,Epg5-/-mice do not display differences in tuft cell numbers and location in the intestine;(2)however,Epg5-/-mice show up-regulation of interferon-related pathway genes.Compared with wild-type mice,the expression of interferon-stimulating genes and some interferon genes are up-regulated in Epg5-/-mice.At the cellular level,(3)there is no significant difference in virus replication in wild-type and Epg5 knockout cells;(4)however,in Epg5 knockout macrophages,the secretion of the virus non-structure protein NS1,which secretion is necessary for virus to infect cells and persistent infection,is blocked.In summary,this study reveals that lack of autophagy gene Epg5 up-regulates the expression of interferon genes and interferon-related genes in the intestine,and blocks the secretion of viral non-structural protein NS1,thereby causing resistance to persistent Norovirus infection.This research provides new insights for the treatment to norovirus infection and the development of vaccines.更多还原