Mechanisms of HCMV-induced monocyte-to-macrophage differentiation.

人巨细胞病毒(HCMV)感染在免疫功能正常的个体中通常是无症状的，尽管在包括动脉粥样硬化和炎症性肠病在内的几种慢性炎症性疾病的病因学中，HCMV是主要的候选病毒。在免疫功能低下的个体中，如新生儿、艾滋病患者和移植受者，HCMV感染可导致急性多器官炎症，导致显著的发病率和死亡率。与巨细胞病毒感染相关的炎症性器官疾病是在无症状或有症状的感染期间发生的系统性病毒传播到多个器官部位并对其进行感染的直接后果。单核细胞负责将病毒运送到组织中，并在受感染器官的炎症状态中发挥核心作用。然而，由于抗凋亡病毒蛋白在感染的早期阶段不表达，目前尚不清楚HCMV如何促进这些短暂细胞的存活和分化。我们发现，在HCMV进入过程中，病毒糖蛋白诱导了Akt的非典型激活，Akt是决定单核细胞存活的关键细胞命运决定因素，这导致受感染单核细胞内早期抗凋亡状态所需的Akt依赖的促生存蛋白的特定子集上调。我们发现，人巨细胞病毒感染对肌醇磷脂(主要研究者)信号网络进行了异常调节，该网络负责调节Akt的活性。因此，我们假设，HCMV糖蛋白刺激Akt的独特激活，导致特定的细胞抗凋亡蛋白的表达，这些蛋白是受感染的单核细胞生存所必需的。目标1将描述病毒糖蛋白在调节主要研究者信号转导中的作用，这是HCMV特异性激活Akt所必需的。我们将描述糖蛋白启动的主要研究者信号受体复合体(ES)的成分。此外，将使用可溶性糖蛋白、中和抗体、小分子抑制剂和siRNAs的组合来证实HCMV诱导的主要研究者信号复合体(ES)中每个成分的功能作用。目的2将确定HCMV启动的主要研究者信号网络异常调节Akt活性的机制。我们将使用siRNAs和小分子抑制剂绘制用于诱导Akt非典型激活的糖蛋白驱动的细胞信号网络。同时，我们将使用糖蛋白中和的HCMV和可溶性糖蛋白来确定来自糖蛋白的协调信号如何改变Akt的底物特异性。目的3阐明巨噬细胞病毒诱导的单核细胞促生存的独特翻译图景是由Akt的异常激活所产生的。我们将通过改变HCMV特异性的主要研究者信号网络来研究HCMV激活的Akt在刺激部分存活蛋白合成中的作用。新发现的病毒诱导的生存蛋白的功能将通过小分子抑制剂和遗传方法得到证实。这些研究将加深我们对巨细胞病毒致病和传播机制的认识。

Human cytomegalovirus (HCMV) infection is generally asymptomatic in immunocompetent individuals, although HCMV is a primary viral candidate in the etiology of several chronic inflammatory diseases including atherosclerosis and inflammatory bowel disease. In immunocompromised individuals, such as neonates, AIDS patients, and transplant recipients, HCMV infection can lead to acute multi-organ inflammation resulting in significant morbidity and mortality. Inflammatory organ diseases associated with a HCMV infection is a direct consequence of the systemic viral spread to and infection of multiple organ sites that occur during either asymptomatic or symptomatic infections. Monocytes are responsible for delivering the virus into tissue and play a central role in the inflammatory state of infected organs. However, because anti-apoptotic viral proteins are not expressed during the early stages of infection, it remains unclear how HCMV promotes the survival and differentiation of these short-lived cells. We found that viral glycoproteins induced an atypical activation of Akt, a critical cell fate determinant of monocyte survival, during HCMV entry, which led to the upregulation of a specific subset of Akt-dependent pro-survival proteins required for the early anti-apoptotic state within infected monocytes. We found HCMV infection aberrantly regulated the phosphoinositide (principal investigator) signaling network, which is responsible for modulating Akt activity. Thus, we hypothesize that HCMV glycoproteins stimulate a unique activation of Akt leading to the expression of select cellular anti-apoptotic proteins specifically required for the survival of infected monocytes. Aim 1 will delineate the role of viral glycoproteins in modulating the principal investigator signaling necessary for the HCMV-specific activation of Akt. We will characterize the components of the glycoprotein-initiated principal investigator signaling receptor complex(es). Additionally, the functional role of each component within the HCMV-induced principal investigator signaling complex(es) will be confirmed using a combination of soluble glycoproteins, neutralizing antibodies, small-molecule inhibitors, and siRNAs. Aim 2 will determine the mechanism by which the HCMV-initiated principal investigator signaling network aberrantly regulates Akt activity. We will map the glycoprotein-driven cellular signaling network used to induce the atypical activation of Akt using siRNAs and small-molecule inhibitors. In conjunction, we will determine how coordinated signaling from glycoproteins alters the substrate specificity of Akt using glycoprotein-neutralized HCMV and soluble glycoproteins. Aim 3 will elucidate the unique HCMV-induced monocyte pro-survival translational landscape generated by the aberrant activation of Akt. We will examine the role of HCMV-activated Akt in stimulating the synthesis of select survival proteins by altering the HCMV-specific principal investigator signaling network. The function of newly identified virus-induced survival proteins will be confirmed by small-molecule inhibitors and genetic approaches. These studies will increase our understanding about the mechanisms of HCMV pathogenesis and dissemination.