B2M-mRNA作为非编码RNA调节I型单纯疱疹病毒复制与复活的机理研究

Human beta 2-microglobulin (B2M) is a protein coding gene identified many years ago. The B2M protein which contains ninety nine amino acids, comprises the light chain of Major Histocompatibility Complex (MHC) I, which exists in nucleated cells and plays an essential role in the antigen presentation of MHC I. In addition to regulating the host immune response, B2M is involved in various physiological and pathologic processes. In our previous study, we found that the mRNA of B2M is a RNA with dual functions, including protein coding capacity and activity as functional RNA. We found that B2M mRNA can function like large non-coding RNA (lncRNA) to enhanced expression of the viral IE and E genes of herpes simplex virus type 1 (HSV-1) by regulating H3K4 trimethylation in the HSV-1 IE and E promoter regions. HSV-1 is a double-stranded DNA virus, which is associated with orofacial herpes infections and is also related to genital herpes infections and herpes encephalitis. After a primary infection that usually occurs in oral-mucosa, the virus replicates within the mucosal epithelial cells and undergoes the lytic life cycle, resulting in lysis of the host cell. Following local replication at the oral-mucosa, HSV-1 travels from the nerve termini to the cell bodies of sensory neurons in the trigeminal ganglia. There, the virus establishes lifelong latency, allowing the existence of a viral genome without replication. Upon the presence of a stress stimulus, the virus is reactivated and returns to the oral-mucosa, initiating relapse. However, the exact mechanism by which the HSV-1 life cycle is regulated has yet to be elucidated. In our previous investigation, we found that B2M was involved in both the replication and reactivation of HSV-1, suggesting that B2M might be one of important factors in life cycle regulation of HSV-1. In this program, we will further study the mechanism of B2M mRNA functions as lncRNA to regulate gene expression and life cycle of HSV-1 and the results will have broad implications for understanding the roles of long non-coding RNA of mammalian in epigenetic control of viral genes and the life cycle regulation of the virus.

人的B2M是一个多年前就已报道的编码蛋白的基因，其蛋白分子有不同的生理和病理功能，特别是作为MHC-I的轻链在抗原呈递中起重要作用。我们在前期研究中发现B2M的mRNA具有双面性,既产生蛋白,其RNA也能作为效应分子发挥功能。B2M的mRNA分子能像长非编码RNA（lncRNA）一样，通过调节组蛋白的修饰来影响单纯疱疹病毒(HSV-1)的基因表达。HSV-1是导致口腔及生殖器疱疹的常见病因，在粘膜的原发感染时大量繁殖造成细胞裂解,然后上行至神经节细胞形成潜伏感染，使患者终身带病毒,直到刺激引起病毒复活。HSV-1生命周期的调控机理尚不清楚。我们在前期研究中发现B2M既能在裂殖周期促进病毒的复制，又影响潜伏期病毒的复活，可能是调节HSV-1生命周期的重要因素。本项目将深入探讨B2M作为lncRNA调节HSV-1基因表达的分子机理及其在HSV-1生命周期调控中的作用，有重要的生物学和临床意义。

单纯疱疹病毒-1（HSV-1）的原发感染主要发生在口腔粘膜部位,病毒在粘膜上皮细胞中繁殖造成细胞的死亡和裂解，并沿着感觉神经末梢上行至附近的神经节，潜伏在神经节。当神经细胞受到刺激时可导致病毒的复活，病毒颗粒再沿着感觉神经末梢下行至粘膜局部造成复发。目前为止,HSV-1从裂解周期到潜伏周期,再到复活的生命周期的调控机理尚不清楚。.本项目研究长非编码核酸（lncRNA）调节HSV-1复制与复活的作用及其机理。我们首先研究了B2M，发现B2M能调节病毒的极早期及早期基因ICP0、ICP27和HSV-TK在RNA和蛋白水平的表达，促进裂殖期HSV-1感染所致的细胞病变及病毒复制。我们还研究了了HSV-1潜伏感染的神经元中B2M的表达对HSV-1复活的影响，证明了B2M是以RNA分子的形式调节病毒基因的表达、促进HSV-1潜伏感染的神经元中HSV-1的复活。最后我们制备了表达人的B2M mRNA的人源化小鼠，动物实验证明HSV-1在人源化小鼠可造成更严重的皮肤病损。.我们还研究了另外一条长非编码核酸 NEAT1，发现该lncRNA也介入了对HSV-1复制的调节。HSV-1感染可造成STAT3介导的NEAT1的表达和paraspeckles的形成增加。抑制NEAT1的表达和paraspeckles的形成能下调病毒基因的表达和阻止病毒的复制。本项目研究了NEAT1、paraspeckle和STAT3在HSV-1感染中的作用，并以NEAT1和HSV-1的极早期基因为例，分析宿主的长非编码核酸与病毒基因之间的相互作用，解析宿主lncRNA调节病毒基因表达的分子机理，并在此基础上研发抑制NEAT1及STAT3表达的小核酸温敏凝胶，用于HSV-1感染所致的皮肤黏膜病变的治疗。本项目的研究对有助于揭示宿主lncRNA调节病毒基因表达的分子机理，有重要的学术意义和潜在的临床应用价值。