Cellular Mechanism of Oxysterol-Binding Protein (OSBP) in Viral Proliferation: A Chemical Biology Approach

当前的 COVID-19 危机清楚地表明需要制定新的模式来应对 致病性单链 RNA (ssRNA) 病毒的治疗，包括针对 尚未出现的新型病毒。人氧甾醇结合蛋白（OSBP）最近被 被确定为广谱 ssRNA 病毒复制的关键介质 人类病原体，包括肠道病毒、鼻病毒、丙型肝炎、寨卡病毒、登革热 病毒和冠状病毒。 OSBP 是一种位于内质网的非酶蛋白，据报道具有功能 作为真核细胞中重要的脂质传感器和脂质转运蛋白。已发表的研究成果，包括 我们自己最近的出版物，已经确定了结构多样化的 OSBP 的抗病毒活性- 针对多种 RNA 致病病毒的小分子。这些发现呈现 抗病毒药物开发范式转变的机会：潜在的药物靶向 人类宿主蛋白 OSBP，是广谱 RNA 病毒增殖所必需的 病毒，而不是针对单个病毒中存在的病毒蛋白。我们发现 使用 OSBP 靶向化合物 OSW-1-compound 进行短暂、低剂量治疗可诱导 OSBP 的长期、多代抑制，并且 OSBP 受到抑制的细胞表现出 显着抑制 ssRNA 病毒复制。我们的初步结果表明，OSW-1- 该化合物在低纳摩尔浓度下对多种病毒具有预防性抗病毒活性 ssRNA 病毒，包括针对一种经过测试的冠状病毒。 OSBP的长期压制， 由 OSW-1 触发，对细胞分裂、活力或形态没有影响。 该提案的目的是了解 OSBP 在先天抗病毒中的细胞作用 回应。我们的初步结果表明 OSBP：1) 调节 mTORC1 活性，2) 诱导 自噬； 3）减慢整体蛋白质翻译； 4）激活选择性剪接废话- 介导的衰变（AS-NMD）过程，这是一个RNA调节过程。所有这些 OSBP- 所涉及的细胞过程会单独限制 ssRNA 病毒复制，但目前还没有深入了解 进入这些系统的组织中，以建立协调的抗病毒反应。我们的总体 假设 OSBP 在协调多方面的先天性方面发挥着重要的调节作用。 对 ssRNA 感染的抗病毒反应。我们提出了一个关于 OSBP 如何早期感知的完整模型 阶段病毒感染，然后触发多系统反应以阻止病毒在细胞中复制， 包括通过调节 mTOR1C 活性和 AS-NMD 系统。

The current COVID-19 crisis starkly illustrates the need to develop new modalities for the therapeutic treatment of pathogenic single-stranded RNA (ssRNA) viruses, including against novel viruses that have yet to emerge. Human oxysterol-binding protein (OSBP) has recently been determined to be a critical mediator in the replication of a broad spectrum of ssRNA viral human pathogens, including the enteroviruses, rhinovirus, hepatitis C, Zika virus, Dengue fever viruses, and coronaviruses. OSBP is an ER-located, non-enzymatic protein reported to function as an important lipid sensor and lipid transporter in eukaryotic cells. Published research, including our own recent publications, has established the antiviral activity of structurally-diverse OSBP- targeting small molecules against multiple RNA pathogenic viruses. These discoveries present the opportunity for a paradigm shift in antiviral drug development: potentially drug targeting a human host protein, OSBP, that is required for viral proliferation of a broad-spectrum of RNA viruses, as opposed to targeting viral proteins present in individual viruses. We have discovered that transient, low dose treatment with the OSBP-targeting compound OSW-1-compound induces a longterm, multigenerational repression of OSBP, and the cells with repressed OSBP show a pronounced inhibition of ssRNA viral replication. Our preliminary results show that the OSW-1- compound has prophylactic antiviral activity at low nanomolar concentrations against several ssRNA viruses, including against one coronavirus tested. The longterm repression of OSBP, triggered by OSW-1, has no effect on cellular division, viability, or morphology. The purpose of this proposal is to understand the cellular role of OSBP in innate antiviral response. Our preliminary results show that OSBP: 1) regulates mTORC1 activity, 2) induces autophagy; 3) slows global protein translation; and 4) activates alternative splicing nonsense- mediated decay (AS-NMD) process, which is an RNA regulatory process. All of these OSBP- involved cellular processes would limit ssRNA viral replication individually, but there is little insight into the organization of these systems to establish a coordinated antiviral response.Our overall hypothesis is that OSBP serves in a major regulatory role to coordinate a multifaceted innate antiviral response to ssRNA infection. We propose a complete model of how OSBP senses early- stage viral infection and then triggers a multisystem response to block viral replication in cells, including through modulating mTOR1C activity and the AS-NMD system.