微颗粒介导HPV感染巨噬细胞的研究—尖锐湿疣复发与免疫逃逸的新途径

Recent studies highlighted that cells during activation or apoptosis released circular membrane fragments called microparticles(MPs), which were capable of transferring bioactive molecules, including viral components, from one cell to another. Further Studies showed that MPs uptaken by macrophages would not be eliminated via phagolysosome patheway. In preliminary study, our team have isolated MPs from digested warts of condylomata acuminata (CA) and observed local accumulation of macrophages in CA，then we found that HPV could infect macrophages in vitro via co-culture with supernatants of fresh genital warts after digestion. These datas together revealed that MPs might act as vehicles and mediate HPV infection of macrophages. Thus, in this study, we hypothesized that (1) genital warts released MPs containing HPV and MPs mediated HPV infection of macrophages; (2) the infected macrophages could produce new HPV and form persistent infection, in turn, HPV could promote macrophages transformation into M2 type and facilitate immune evasion of viral infection. This study focuses on MPs and tries to elucidate the pathway macrophages infected by HPV and the anti-HPV function changes after that，via isolating MPs from CA warts and co-culture with macrophages. The expected fingdings might provide novel understanding about mechanisms of CA immune evasion and also reason of high recurrent rate of CA at macrophage aspect.

最新研究表明，细胞在激活或凋亡时能够释放微颗粒，它可作为载体将包括病毒成分在内的生物活性分子在细胞间转移；研究还发现，微颗粒能被巨噬细胞摄取，其摄取后不被吞噬-溶酶体所清除。课题组前期从尖锐湿疣（CA）组织中分离到微颗粒，并且观察到CA组织中存在较多巨噬细胞，其在体外与消化的CA组织上清孵育可导致HPV感染，提示微颗粒可能作为载体介导HPV感染巨噬细胞。基于上述分析，本项目假设：CA组织能产生包裹HPV的微颗粒，并介导HPV感染巨噬细胞，一方面在巨噬细胞内合成新的HPV形成持续感染，另一方面HPV感染教育巨噬细胞向M2型发展，促进HPV感染的免疫逃逸。本课题以微颗粒为切入点，从CA组织中分离微颗粒与巨噬细胞共培养，对微颗粒介导HPV感染人巨噬细胞的过程及其抗HPV功能的转变展开深入研究，并探讨其内在机制。这将从巨噬细胞的角度阐述CA新的免疫逃逸途径，同时也将揭示CA高复发率的另一可能原因。

尖锐湿疣（CA）复发是临床治疗难题，探究复发背后的潜在机制和寻找有效的治疗方法一直是尖锐湿疣研究的热点和难点。表皮的正常更替依赖于表皮干细胞及其子代细胞的有序增殖、逐级分化成各层角质形成细胞，最终在角质层走向终末分化而逐渐脱落。而在CA组织中，感染人乳头瘤病毒（HPV）后基底层细胞失去正常增殖分化过程，表现为病理性增殖的棘层样细胞，最终形成疣体；感染HPV后同样激活机体免疫系统，巨噬细胞被募集到感染部位并活化，激活的巨噬细胞可吞噬病毒颗粒，杀伤病毒感染的靶细胞，并促进获得性免疫应答。本团队前期建立了低剂量环磷酰胺（CTX）治疗CA的新方法，大部分患者治疗后疣体消退或缩小，复发率降低，且CA疣体局部的免疫微环境也得到了改善。因此，本课题从疣体中角质形成细胞的病理性增殖、疣体局部免疫微环境和低剂量CTX治疗后疣体组织中细胞增殖、凋亡和分化情况入手，探究CA复发的潜在机制。我们的研究表明：（1）HPV病毒颗粒可通过包含在微颗粒中感染巨噬细胞，进而形成免疫逃逸，引起CA复发；（2）对正常组织和CA组织进行mRNA表达谱测序分析结果表明，疣体中角质形成细胞代谢模式发生变化以维持其生存和不断增殖，对深入理解CA复发机制具有重要意义；（3）经低剂量CTX治疗CA后，患者复发率降低，疣体组织中HPV病毒载量降低，角质形成细胞和表皮干细胞增殖减少，凋亡增加，这也为进一步探索CA复发机制和有效治疗方法提供了有利的证据。