【作者】 李英；

【导师】 赵宇岚；

【作者基本信息】 华东师范大学 ， 生理学， 2021， 硕士

【摘要】 朊蛋白因其能够发生构象转变导致朊病毒病而得到广泛研究。目前对朊蛋白构象和其在神经系统中的作用的研究比比皆是,但对它的基本生理功能研究甚少。PrP在多种免疫细胞中的表达让它在免疫系统中的作用不容忽视,但迄今鲜有这一方面的研究。硬皮病的病理特征是皮肤增厚并纤维化,属于自身免疫病,其病因复杂。但作为自身免疫病,免疫功能失调可能是主要原因。本课题通过在正常小鼠和PrP敲除鼠上构建硬皮病模型,比较小鼠基因型之间的差异,以此来理解PrP对硬皮病的作用,从而认识PrP在免疫系统中的作用。在C57/BL/S129杂合背景的WT（野生型）、PrP^-/-（朊蛋白敲除型）、Tga20（朊蛋白高表达型）和C57B/L背景的C57BL6（野生型）、KO（朊蛋白敲除型）、△OR（朊蛋白N端八肽重复区敲除型）小鼠背部皮肤皮下注射博来霉素,构建动物硬皮病模型。对小鼠皮肤和肺的石蜡切片进行HE染色,Masson染色和天狼星红染色,并比较皮肤厚度。通过QPCR比较胶原因子表达情况。利用免疫组化和QPCR定性定量检测小鼠皮肤和肺的巨噬细胞表达情况。实验结果表明,和野生型（WT和C57 WT）小鼠相比,PrP完全缺失的小鼠(PrP^-/-和KO)硬皮病症状减轻,表现为皮肤较薄,皮肤和肺的胶原因子低表达,说明PrP的存在会促进硬皮病的发展。而△OR鼠和野生型结果一致,提示我们敲除八肽重复区并不能影响硬皮病。模型小鼠和正常小鼠相比,有更多的巨噬细胞浸润,表示巨噬细胞参与硬皮病进程。相较于WT和Tga20小鼠来说,M1巨噬细胞在PrP^-/-小鼠皮肤中高表达,M2巨噬细胞在肺中低表达,提示不同的组织器官中主导硬皮病进程的巨噬细胞不同,这有助于理解硬皮病的病因。综上所述,全长PrP敲除能减轻实验性硬皮病,只敲除八肽重复区无此作用,PrP敲除鼠皮肤M1巨噬细胞表达较高,而肺M2巨噬细胞表达偏低。因而可能在不同受累器官中巨噬细胞有不同的极化方向,影响到硬皮病进程。更多还原

【Abstract】 Prion protein（PrP）has been widely studied as its conformational transformation leading to prion disease.To date,there has been a pile studies about prion protein conformation and its role in nervous system.However,till now basic physiological function of PrP remains unclear.Although,the expression of prion protein in a variety of immune cells suggests it may play an important role in the immune system,there are few studies on this aspect.Systemic sclerosis（SSC）is characterized by thickening and fibrosis of skin,which belongs to autoimmune disease with complicated etiology.As an autoimmune disease,immune dysfunction may play a leading role in the pathogenesis.In order to understand the roles of PrP in SSC and immune system,we constructed SSC model in normal mice and PrP knockout mice,and compared the differences between mouse genotypes.The C57/BL/S129 heterozygous background WT（wild type）,PrP^-/-（PrP knockout type）,Tga20（PrP high expression type）and C57B/L background C57BL6（wild type）,KO（PrP knockout type）and△OR（Octapeptide repeat knockout type）mice were injected with bleomycin subcutaneously into the back skin to construct animal SSC models.The paraffin sections of mouse skin and lung were stained with HE,Masson and Sirius Red,and the skin thickness was compared.The expression of collagen factor was compared by QPCR.Immunohistochemistry and QPCR were used to detect the expression of macrophages in the skin and lung of mice.The results showed that compared with WT and C57 WT mice,the symptoms of SSC in PrP^-/-and KO mice were alleviated,with thinner skin and lower expression of collagen factor in skin and lung,indicating that the presence of PrP will promote the development of scleroderma.The results of△OR mice were consistent with those of wild type,suggesting that deletion of OR only could not affect SSC.Compared with WT and Tga20 mice,M1 macrophages were highly expressed in the skin of PrP^-/-mice,while M2 macrophages were poorly expressed in the lung,suggesting that macrophages involved in the progress of SSC are different in different tissues and organs.In a summary,deletion of full-length PrP,but not OR only,could alleviate experimental SSC.PrP knockout mice showed higher expression of M1 macrophages in skin tissue,but lower expression of M2 macrophages in lung tissue.It is possible that macrophage polarization pattern may be different in different organs.更多还原