Ku70负性调控HTLV-1病毒感染的功能和机制研究

Cytosolic DNA sensors are able to recognize the DNA forms produced during the life cycle of retroviruses and privide new angels about the research on retroviruses. However,there is little report about which cytosolic DNA sensor is responsible for HTLV-1 recognition and replication regulation. Our data showed that the expression of Ku70, which is a known cytosolic DNA sensor, was induced by HTLV-1 infection in PMA-THP-1 cells (PMA-differentiated THP-1 cells, a human macrophage-like cell line),and the overexpression of Ku70 inhibited the expression of HTLV-1 protein Tax and p19 at mRNA levels. We will investigate the role of Ku70 in HTLV-1 infection by the methods of RNAi silence, westernblot, realtime PCR, ELISA and luciferase assay etc. in primary human monocyte-derived macrophages (hMDMs) and in PMA-THP-1 cells. Furthermore, we will illuminate the role of IFN Ⅲ in this course. We would propose a new opinion that cytosolic DNA sensor Ku70 could recognize the DNA forms produced by HTLV-1 and negatively regulate the HTLV-1 replication. This research will provide new angles to understand the HTLV-1 infection associated diseases.

胞内DNA识别受体对逆转录病毒生活史中产生的DNA形式的识别为逆转录病毒的研究开启了新思路。但HTLV-1感染过程中哪种胞内DNA识别受体参与了病毒的识别和复制调控，目前尚不清楚。我们研究发现胞内DNA识别受体Ku70在PMA-THP-1细胞(PMA诱导分化的THP-1细胞，类似人的巨噬细胞)中由HTLV-1的感染诱导表达，且过表达Ku70抑制了HTLV-1病毒蛋白Tax和p19在mRNA水平上的表达。我们拟通过RNAi、westernblot、实时定量PCR、ELISA及荧光素酶报告基因实验等方法分别在人类原代单核细胞和PMA-THP-1细胞中探讨Ku70在HTLV-1感染过程中的功能及具体机制，并揭示Ⅲ型IFN在这一过程中扮演的角色。提出Ku70识别HTLV-1产生的DNA形式并负性调控HTLV-1复制的新观点，为深入理解HTLV-1感染相关疾病的病理过程提供了新角度。

人类T细胞白血病1型病毒属于逆转录病毒机组成员，与多种人类疾病相关。然而，针对HTLV-1的固有免疫应答反应并不清楚。本项研究中，我们的研究显示，Ku70，一种已知的针对DNA病毒的DNA识别受体，在HeLa细胞、PMA诱导分化的THP-1细胞、原代培养的人单核细胞以及人单核细胞诱导的巨噬细胞中可由HTLV-1感染诱导表达。在这些细胞中，Ku70的过表达可抑制HTLV-1病毒蛋白的表达，Ku70基因沉默可促进HTLV-1病毒蛋白表达。并且，Ku70的过表达可增强细胞内针对HTLV-1感染的固有免疫应答反应，而沉默Ku70则有相反的效果。另外，Ku70与HTLV-1的反转中间体ssDNA90存在相互作用。ssDNA90刺激可诱导Ku70的表达且Ku70可促进ssDNA90触发的固有免疫应答反应。最后，HTLV-1感染可增强Ku70与STING的相互作用，提示STING参与Ku70介导的针对HTLV-1感染的宿主防御应答反应。总之，我们的研究表明DNA识别受体Ku70可感知HTLV-1的反转中间体并调控HTLV-1的复制。这些研究对理解针对HTLV-1感染的宿主细胞免疫应答反应以及HTLV-1相关疾病提供了新角度。