Role of Frizzled 5 in NK cell development and antiviral host immunity

项目总结 自然杀伤(NK)细胞已被证明在免疫介导的病毒控制中起主导作用 在人类和小鼠身上都有感染。缺乏NK细胞或NK细胞功能的人死于致命的病毒 感染，如人类巨细胞病毒(HCMV)。同样，缺乏成熟外周NK细胞的新生小鼠 小鼠巨细胞病毒(MCMV)对NK细胞缺陷的成年小鼠非常敏感。 感染。鉴于巨细胞病毒的临床意义，小鼠的巨细胞病毒感染是一种合适的模型 研究NK细胞介导的抗病毒免疫。虽然NK细胞是先天免疫系统的成员，但现在它是 认识到NK细胞与CD8+T细胞有许多共同的特征，并可以表现出适应性的特征 豁免权。尽管我们对NK细胞的先天和适应性特征的了解在过去有所增加 十年来，它们的发育和最佳抗病毒反应的分子和转录控制仍然存在 不清楚。 考虑到NK细胞和CD8+T细胞之间的共同特征以及CD8+T细胞中的Wnt信号 细胞对生存和介导对病原体的反应是有帮助的，我假设Wnt信号 在NK细胞存活和抗病毒功能中起着至关重要的作用。然而，Wnt信号在NK细胞中的作用 在很大程度上是未被开发的。因此，这项提议试图探索1)Wnt信号是如何在NK细胞中介导的，2) 哪些Wnt配体正在调节NK细胞？这些配体的来源是什么？3)什么是 在NK细胞发育和宿主抗病毒防御过程中，由Wnt信号调控的分子事件。 在分析与Wnt配体结合的Frizzleed(Fzd)受体家族时，我发现Fzd5是 与其他免疫细胞相比，在NK细胞上显著且特异地表达。调查……的作用 Fzd5在NK细胞中的表达，我构建了一种新的含有NK细胞特异性缺失的Fzd5的转基因小鼠。在……里面 初步数据显示，Fzd5缺陷小鼠的NK细胞数量减少，令人惊讶的是，混合骨髓中的NK细胞数量减少 与野生型NK细胞相比，嵌合体Fzd5缺陷的NK细胞对小鼠的再繁殖能力较差。 此外，Fzd5对于NK细胞对MCMV的正确抗原特异性克隆性增殖是必不可少的。 感染。在具体目标1中，我将确定FZD5信号的下游介体，并确定WNT 与NK细胞表面Fzd5结合的配体。在特定的目标2中，我将研究Wnt的分子机制 NK细胞抗病毒反应中的信号转导。 在完成本F31之后，我们将获得对复杂转录网络的关键见解，这些网络是 由Fzd5诱导。从这项研究中得出的机械论见解将有助于 增强NK细胞功能并影响旨在改进抗病毒治疗的策略的新疗法。

PROJECT SUMMARY Natural killer (NK) cells have been shown to play a dominant role in the immune-mediated control of viral infection in both humans and mice. Individuals lacking NK cells or NK cell function succumb to fatal viral infections, such as human cytomegalovirus (HCMV). Similarly neonatal mice, which lack mature peripheral NK cells, and adult mice with NK cell deficiencies are extremely susceptible to murine cytomegalovirus (MCMV) infection. Given the clinical significance of HCMV, MCMV infection in mice represents an appropriate model to study NK cell-mediated antiviral immunity. While NK cells are members of the innate immune system, it is now appreciated that NK cells share many characteristics with CD8+ T cells and can exhibit features of adaptive immunity. Although our understanding of the innate and adaptive features of NK cells has increased in the past decade, the molecular and transcriptional control of their development and optimal antiviral response remains unclear. Given the shared characteristics between NK cells and CD8+ T cells and that Wnt signaling in CD8+ T cells is instrumental for survival and in mediating responses against pathogens, I postulate that Wnt signaling plays an essential role in NK cell survival and antiviral function. However, the role of Wnt signaling in NK cells is largely unexplored. Thus, this proposal seeks to explore 1) how Wnt signaling is mediated in NK cells, 2) what Wnt ligands are modulating NK cells and what is the source of these ligands, and 3) what are the molecular events orchestrated by Wnt signaling in NK cells during development and host antiviral defense. While profiling the Frizzled (Fzd) family of receptors that bind to Wnt ligands, I found that Fzd5 is prominently and exclusively expressed on NK cells compared to other immune cells. To investigate the role of Fzd5 in NK cells, I generated a novel transgenic mouse containing NK cell-specific deletion of Fzd5. In preliminary data, Fzd5-deficient mice had diminished NK cell numbers and, strikingly, in a mixed bone marrow chimera, Fzd5-deficient NK cells were less capable of repopulating mice compared to wildtype NK cells. Additionally, Fzd5 is essential for proper antigen-specific clonal expansion of NK cells in response to MCMV infection. In Specific Aim 1 I will identify the downstream mediators of Fzd5 signaling and identify the Wnt ligand that binds to Fzd5 on NK cells. In Specific Aim 2 I will investigate the molecular mechanism of Wnt signaling in NK cell antiviral responses. At the completion of this F31 we will gain key insights into the complex transcriptional networks that are induced by Fzd5. The mechanistic insights derived from this study will be instrumental in the development of novel therapies that enhance NK cell function and influence strategies aimed at improving antiviral therapies.