单纯疱疹病毒Ⅰ型（HSV-1）感染率高，易反复再激活，引起皮肤黏膜疱疹及致盲率首位的角膜炎、肝炎、脑膜炎等严重损害。 其复发是病毒与宿主相互作用的结果，机制不完全清楚。研究证明STAT1是宿主抗病毒干扰素通路的关键分子，其功能受SUMO化和磷酸化等修饰的影响。我们前期研究了一个HSV-1复发家系，发现SUMO异肽酶USPL1突变和该家系的HSV-1反复复发有关联。结合前期基础，我们提出USPL1的突变影响STAT1的SUMO化，抑制STAT1的磷酸化，导致HSV-1感染复发的假说。为此，我们拟构建USPL1野生型和点突变真核表达载体，感染筛选获得相应稳定的淋巴细胞系，检测USPL1突变对该细胞系STAT1的SUMO化和磷酸化的影响，以及HSV-1感染时STAT1通路及宿主防御因子的变化。最终明确USPL1调节STAT1稳定性在抗病毒中的新机制，为寻找新的预防HSV-1复发的靶点打下基础。

Herpes simplex virus type 1 (HSV-1) is a ubiquitous human pathogen causing a recurrent infection that lasts for the lifetime of the host， ranging from mucocutaneou infection to severe keratitis which is leading cause of blindness，and hepatitis to meningitis in patients whose immunity is compromised. The recurrence of HSV-1 is a result of interaction between virus and host, and the mechanism is not clear. STAT1 is a pivotal transcription factor for generation of the interferon (IFN)-dependent antiviral response，and regulated by SUMO and phosphorylation. We previously found a familial occurrence of recurrent HSV-1. Using genome-wide approach and exome sequencing, in the patients of the family, we identified a denovo point mutation in the ubiquitin-specific peptidase-like1 gene (USPL1) which is a surprising new SUMO protease. this is the first found of recurrent HSV-1 infection related to USPL1 mutation. These results indicate that point mutation in USPL1 is probably involved in the SUMO of STAT1 and inhibiting phosphorylated STAT1 and leading to recurrent HSV-1 infection. In present project, we will construct the retroviral vector of USPL1 with point mutation， and Jurkat cells will be transfected with the recombinant. Then we examine the expression of SUMO of STAT1 and phosphorylated STAT1 in Jurkat cells with and without HSV-1 infection. The study will provide a new experimental basis to clarify the the effect of USPL1 in antvirus role by stabilizing STAT1, and to reveal novel therapeutic targets in HSV-1 infection.

单纯疱疹病毒 I 型（herpes simplex virus type I, HSV-I）感染是世界上最流行的感染之一，往往在幼年感染，可终生携带，至今尚无完全治愈该病毒的药物。课题组前期研究了一个HSV-1复发家系，发现患者出现SUMO异肽酶USPL1突变。USPL1是新发现的一种SUMO异肽酶，我们推测USPL1的突变可能增加干扰素扛病毒途径关键分子STAT1的SUMO化，抑制下游相关抗病毒基因的表达，进而造成细胞对HSV-1病毒的抵抗降低，造成病毒再次活跃。为验证这一推测，我们构建了USPL1的三组慢病毒载体:对照组、野生型组、突变组。并将这三组慢病毒转染人口腔上皮癌KB细胞系。并对三组细胞进行了细胞增殖、周期、凋亡进行了检测，还检测了三组细胞中STAT1的SUMO化程度，STAT1下游基因的表达，以及HSV病毒感染后的细胞状态。结果表明USPL1对细胞的生长没有显著影响；USPL1突变组细胞STAT1的SUMO化程度显著增加；突变组较野生型组细胞中STAT1下游基因表达下调；HSV感染后突变组细胞生长状态较野生型组差。以上结果证实了USPL1基因2849bp(rs3742302)碱基突变通过改变STAT1的SUMO化程度参与HSV-1复发。本研究有助于深入理解病毒对宿主细胞感染的机制，为抗病毒治疗提供一些新的思路。为寻找新的预防HSV-1复发的药物打下基础。