SUMO异肽酶USPL1突变致单纯疱疹病毒Ⅰ型感染复发的分子机制研究

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（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。