Transcriptional mechanisms of natural killer cell responses during mouse cytomegalovirus infection

项目摘要 自然杀伤(NK)细胞是免疫系统中的淋巴细胞，可以检测并杀死病毒感染的细胞。 流行病学研究表明，免疫抑制患者(如癌症、器官移植、艾滋病) 新生儿表现出与人类巨细胞病毒相关的健康并发症的风险增加 可能危及生命的巨细胞病毒(HCMV)感染。先前的工作表明，小鼠巨细胞病毒(MCMV) 小鼠的感染可以准确地模拟人巨细胞病毒的感染，并证明NK细胞在 MCMV的控制。此外，NK细胞已被证明具有适应性免疫系统的特性 例如小鼠、猕猴和人类的回忆反应、抗原特异性和克隆性扩增。虽然 我们的工作在阐明自噬和有丝分裂是如何导致世代的方面取得了重大进展 记忆NK细胞和增殖的淋巴细胞的生存，这些上游调节元件 体内淋巴细胞的基本生物学过程仍然知之甚少。我们的长期目标是 识别诱导记忆性NK细胞自噬、有丝分裂和存活的相关转录信号 病毒感染后的细胞。在RNA测序实验中，我们已经确定Trp73(P73)是一种 小鼠巨细胞病毒(MCMV)诱导的记忆NK细胞选择性富含转录因子 感染。进一步的实验验证表明，Trp73在小鼠体内有两种主要的亚型 (TAp73和ΔNp73)在巨细胞病毒感染的NK细胞中表现出不同的时间表达模式。 重要的是，p73转录异构体在体内淋巴细胞对病毒感染的反应中的作用是 未知。我们令人兴奋的初步发现表明，ΔNp73在效应NK细胞中是瞬时诱导的，并且是 是记忆NK细胞克隆扩增和生成所必需的。相反，TAp73的表达是持续的 在效应器和记忆性NK细胞中，对效应器NK细胞的增殖是必不可少的，但对生存和 记忆性NK细胞的产生。在目标1中，我们将确定TAp73是否会影响自噬清除 NK细胞线粒体功能障碍促进效应NK细胞向记忆转化时的存活 使用尖端的自噬和新陈代谢分析。在目标2中，我们将确定Δnp73是否领先 通过抑制P53抑制效应NK细胞的增殖以保护NK细胞免于凋亡或缓解 抑制细胞周期。在目标3中，我们将进行RNA和芯片测序实验来确定基因 利用基因组分析研究p73在效应NK细胞中的靶点。总括而言，本报告所载的拟议研究 R01建议将有助于我们对原代细胞如何在体内诱导有丝分裂吞噬的基本理解，而 也有助于新的临床战略，以加强适应性自然杀伤细胞免疫反应的使用 对抗传染病。

Project Summary Natural killer (NK) cells are lymphocytes of the immune system that can detect and kill virally infected cells. Epidemiological studies have shown that immunosuppressed (e.g. cancer, organ transplant, AIDS) patients and newborns display an enhanced risk for health complications associated with human cytomegalovirus (HCMV) infection that can be life-threating. Previous work has shown that mouse cytomegalovirus (MCMV) infection in mice can accurately model HCMV infection, and demonstrated that NK cells are critical for the control of MCMV. Furthermore, NK cells have been shown to have properties of the adaptive immune system such as recall responses, antigen-specificity, and clonal expansion in mice, macaques, and humans. Although our work has made significant progress into elucidating how autophagy and mitophagy lead to the generation of memory NK cells and the survival of proliferating lymphocytes, the upstream regulatory elements of these fundamental biological processes remain poorly understood in lymphocytes in vivo. Our long-term goals seek to identify the relevant transcriptional signals that induce autophagy, mitophagy, and survival of memory NK cells following viral infection. In RNA-sequencing experiments, we have identified Trp73 (p73) as a transcription factor selectively enriched in memory NK cells following murine cytomegalovirus (MCMV) infection. Further experimental validation by qRT-PCR revealed that two dominant isoforms of Trp73 in mice (TAp73 and ΔNp73) display distinct temporal expression patterns in NK cells during MCMV infection. Importantly, the roles of p73 transcriptional isoforms in lymphocyte responses to viral infection in vivo are unknown. Our exciting preliminary findings suggest that ΔNp73 is transiently induced in effector NK cells and is required for clonal expansion and generation of memory NK cells. In contrast, TAp73 expression is sustained in effector and memory NK cells and is dispensable for effector NK proliferation, but critical for the survival and generation of memory NK cells. In Aim 1, we will determine whether TAp73 influences autophagic removal of dysfunctional mitochondria in NK cells to promote the survival of effector NK cells as they transition to memory cells using cutting-edge autophagy and metabolism assays. In Aim 2, we will determine whether ΔNp73 leads to the proliferation of effector NK cells through repression of p53 to shield NK cells from apoptosis or relieve cell cycle repression. In Aim 3, we will perform RNA and ChIP-sequencing experiments to determine the gene targets of p73 in effector NK cells using genomic analyses. In summary, the proposed studies included in this R01 proposal will contribute to our basic understanding of how primary cells induce mitophagy in vivo, while also contributing to novel clinical strategies to enhance the use of adaptive NK cell responses for immunization against infectious disease.