Mechanisms of Human Cytomegalovirus Reprogramming of Lipid Metabolism

项目摘要 人巨细胞病毒（HCMV）是一种疱疹病毒，可导致疾病和死亡， 免疫功能低下，是先天性残疾的主要原因。HCMV复制需要脂质。 由于HCMV不编码代谢网络，病毒复制依赖于宿主脂质代谢。 然而，关于HCMV如何重新编程宿主代谢以确保病毒所需的脂质， 复制已经完成。我们的总体目标是了解调节脂质合成的病毒-宿主相互作用 对HCMV复制至关重要。最近，我们发现HCMV感染导致脂质增加， 合成和脂质丰度增加。在这里，我们证明了HCMV感染诱导合成 至少20种以前未描述的感染细胞特有的脂质。这些独特的脂质大部分是磷脂 具有极长链脂肪酸尾（PL-VLCFA）。本申请中讨论的PL-VLCFA是 在我们的工作之外，对HCMV生物学的研究还不够。虽然较短的FA尾已经 尽管研究得很好，但我们对带有VLCFA尾巴的脂质知之甚少，这些尾巴与我们在HCMV中观察到的尾巴一样长 感染，包括它们在生物膜中的行为。这背后的分子机制 HCMV诱导的宿主脂质组的扩增和新产生的脂质的功能作用是 大部分未知。 我们发现HCMV pUL 37 x1和pUL 38蛋白促进PL-VLCFA的合成，奠定了HCMV pUL 37 x1和pUL 38蛋白在PL-VLCFA合成中的作用。 为理解HCMV重编程脂质合成的机制奠定了基础。pUL 37 x1和 pUL 38分别诱导Ca 2+和mTOR信号传导。我们有初步数据表明压力 与这些信号通路相关的应答有助于脂质的HCMV重塑。我们假设 pUL 37 x1和pUL 38使用Ca 2+和mTOR信号传导来促进PC-VLCFA的合成，所述PC-VLCFA是 HCMV复制。我们将通过确定pUL 37 x1和pUL 38在细胞中表达的机制来检验这一假设。 促进PL-VLCFA的合成（目的1）和定义HCMV所需的PL-VLCFA合成酶 复制和PL-VLCFA在感染中的作用（目的2）。这些研究将确定机制， HCMV与宿主相互作用，创造独特的脂质环境，促进我们对HCMV的认识 重新编程新陈代谢。此外，这些研究将确定PC-VLCFA的生物学功能 在HCMV复制中的作用，并进一步加深了我们对HCMV感染所需脂质的理解。确定 HCMV诱导的脂质代谢重编程和PC-VLCFA功能的机制将 需要HCMV生物学的先进知识来确定治疗感染的新靶点。

PROJECT SUMMARY Human cytomegalovirus (HCMV) is a herpesvirus that causes disease and death in the immunocompromised and is a leading cause of congenital disabilities. HCMV replication requires lipids. Since HCMV does not encode a metabolic network, virus replication depends on host lipid metabolism. However, little is known about how HCMV reprograms host metabolism to ensure lipids required for virus replication are made. Our overall goal is to understand the virus-host interactions that regulate lipid synthesis essential for HCMV replication. Recently, we showed that HCMV infection results in an increase in lipid synthesis and a rise in lipid abundances. Here we demonstrate that HCMV infection induces the synthesis of at least 20 previously undescribed lipids unique to infected cells. Most of these unique lipids are phospholipids with very long-chain fatty acid tails (PL-VLCFAs). The PL-VLCFAs discussed in this application are understudied in general and unstudied in HCMV biology beyond our work. While shorter FA tails have been well-studied, we know little about lipids with VLCFAs tails that are as long as those we observe in HCMV infection, including how they will behave in a biological membrane. The molecular mechanisms underlying this HCMV-induced expansion in the host lipidome and the functional roles of the newly generated lipids are largely unknown. We discovered that HCMV pUL37x1 and pUL38 proteins promote PL-VLCFA synthesis, laying the foundation for understanding the mechanisms by which HCMV reprograms lipid synthesis. pUL37x1 and pUL38 induce Ca2+ and mTOR signaling, respectively. We have preliminary data suggesting that stress responses related to these signaling pathways contribute to HCMV remodeling of lipids. We hypothesize that pUL37x1 and pUL38 use Ca2+ and mTOR signaling to promote the synthesis of PC-VLCFAs required for HCMV replication. We will test this hypothesis by determining the mechanisms by which pUL37x1 and pUL38 promote synthesis of PL-VLCFAs (Aim 1) and defining the PL-VLCFA synthesis enzymes required for HCMV replication and the role of PL-VLCFAs in infection (Aim 2). These studies will determine the mechanisms by which HCMV interacts with the host to create a unique lipid environment advancing our knowledge of HCMV reprogramming of metabolism. Furthermore, these studies will define the biological functions of PC-VLCFAs in HCMV replication and further our understanding of lipids required for HCMV infection. Determining the mechanisms involved in HCMV-induced reprogramming of lipid metabolism and functions of PC-VLCFAs will advance knowledge in HCMV biology needed to identify new targets for treating infection.