CHEETAH Center for the Structural Biology of HIV Infection, Restriction, and Viral Dynamics

CHEETAH HIV 感染、限制和病毒动力学结构生物学中心

• 批准号: 10663368
• 负责人: Owen Pornillos
• 金额: $ 114.89万
• 依托单位: UNIVERSITY OF UTAH
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-07-11 至 2027-04-30
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10663368
• 关键词: APOCEC3G gene; Affect; Antiviral Agents; Antiviral Response; Binding; Biological Assay; Biology of HIV Infection; Capsid; Cell-Free System; Cells; Cryoelectron Microscopy; Detection; Dissociation; Excision; Genetic; Goals; HIV; HIV-1; HIV/AIDS; Human; Immune; Immunologic Factors; In Vitro; Infection; Innate Immune Response; Integration Host Factors; Interferons; Interruption; Learning; Life Cycle Stages; Lipid Bilayers; Lipids; Mediating; Membrane Fusion; Modeling; Molecular Conformation; Myeloid Cells; Pathway interactions; Process; Proteins; Reaction; Recombinants; Regulation; Reverse Transcription; Role; Running; Serine; Signal Transduction; Structure; System; TRIM Gene; TRIM5 gene; Testing; Therapeutic; Transcript; Ubiquitination; Viral; Viral Physiology; Virion; Virus; Virus Replication; antiretroviral therapy; cofactor; design; experimental study; inhibitor; innate immune sensing; insight; novel; phospholipid scramblase; pressure; reconstitution; response; sensor; structural biology; transmission process; viral rebound; viral transmission

PROJECT SUMMARY Although untreated HIV/AIDS infections are fatal, humans nevertheless have an array of powerful innate antiviral responses that help suppress replication and exert strong selective pressures on the virus during transmission and during viral rebound following ART interruption. These observations suggest that innate immune responses could be of therapeutic value if we can understand them better and discover ways to strengthen them. To infect a cell, HIV-1 must run a gauntlet of such innate immune sensors and restrictions. Studies in Project 2, Cellular Defenses Against HIV, will reconstitute and characterize the mechanisms of cellular innate immune sensing and restriction of HIV-1 that occur during the first half of the viral life cycle. Studies in Aim 1 (SERINC Structure, Mechanism, and Antiviral Activity) will build on our recent cryoEM structure of hSERINC3, and our discoveries that restricting SERINCs are nonspecific phospholipid scramblases and that loss of phosphatidyl serine (PS) asymmetry elicits antiviral effects. We hypothesize that SERINCs inhibit HIV-1 entry by altering the natural asymmetry of the virion lipid bilayer. We propose to determine how SERINCs flip lipids, and to test whether SERINCs exert their antiviral activities by altering PS distribution and disrupting Env conformations. Studies in Aim 2 (HIV-1 Recognition and Innate Signaling) will leverage our ability to reconstitute cGAS innate immune sensing of replicating HIV cores in vitro and our discovery that HIV-1 capsid inhibitors can promote innate signaling in infected myeloid cells. We now propose to determine: 1) how viral core structure and stability affect cGAS-mediated detection of reverse transcription, 2) how capsid-binding factors such as PQBP1 contribute to cGAS sensing in myeloid cells, 3) whether and how CA inhibitors can promote cGAS detection of HIV-1, 4) how cell-specific factors regulate cGAS activity, and 5) how the resulting downstream responses restrict HIV-1 infection. Studies in Aim 3 (TRIM Restrictions) will follow from our observation that TRIM5 proteins form hexagonal cages around incoming HIV-1 capsids. Experiments in this Aim are designed to fill fundamental gaps in our understanding of the viral inhibition and signaling processes that follow this initial TRIM5 recognition step, and to discover how host cofactors facilitate or modulate TRIM5 restriction. Studies in Aim 4 (Reconstitution of Other Restrictions) will build on our ability to reconstitute SAMHD1 and APOBEC3G restriction of replicating HIV-1 cores in vitro, and we now propose to reconstitute MxB restriction. These reconstituted reactions will be used to fill gaps in our understanding of restriction mechanisms, cofactors, and regulation, and to examine how capsid inhibitors can enhance MxB activity.

项目概要 尽管未经治疗的艾滋病毒/艾滋病感染是致命的，但人类仍然具有一系列强大的先天抗病毒反应 有助于抑制复制并对病毒在传播和病毒反弹期间施加强大的选择性压力 ART 中断后。这些观察结果表明，如果我们 可以更好地理解它们并找到加强它们的方法。为了感染细胞，HIV-1 必须面对这种先天性的挑战。 免疫传感器和限制。项目 2“针对 HIV 的细胞防御”的研究将重建并表征 细胞先天免疫感应和 HIV-1 限制的机制发生在病毒生命周期的前半部分。 目标 1（SERINC 结构、机制和抗病毒活性）的研究将建立在我们最近的冷冻电镜结构的基础上 hSERINC3，以及我们发现限制 SERINC 的是非特异性磷脂杂乱酶，并且损失 磷脂酰丝氨酸 (PS) 不对称性会引发抗病毒作用。我们假设 SERINCs 通过改变 病毒粒子脂质双层的自然不对称性。我们建议确定 SERINCs 如何翻转脂质，并测试是否 SERINC 通过改变 PS 分布和破坏 Env 构象来发挥其抗病毒活性。 目标 2（HIV-1 识别和先天信号传导）的研究将利用我们重建 cGAS 先天免疫的能力 体外复制 HIV 核心的传感以及我们发现 HIV-1 衣壳抑制剂可以促进先天信号传导 感染的骨髓细胞。我们现在建议确定：1）病毒核心结构和稳定性如何影响 cGAS 介导的 逆转录检测，2) PQBP1 等衣壳结合因子如何促进骨髓中的 cGAS 传感 细胞，3) CA 抑制剂是否以及如何促进 HIV-1 的 cGAS 检测，4) 细胞特异性因子如何调节 cGAS 活性，以及​​ 5) 由此产生的下游反应如何限制 HIV-1 感染。 目标 3（TRIM 限制）的研究将根据我们的观察进行，即 TRIM5 蛋白在周围形成六角形笼 传入的 HIV-1 衣壳。该目标中的实验旨在填补我们对病毒理解的根本空白 最初的 TRIM5 识别步骤之后的抑制和信号传导过程，并发现宿主辅因子如何 促进或调节 TRIM5 限制。 目标 4（其他限制的重构）的研究将建立在我们重构 SAMHD1 和 APOBEC3G 的能力之上 体外复制 HIV-1 核心的限制，我们现在建议重建 MxB 限制。这些重构的 反应将用于填补我们对限制机制、辅因子和调节的理解空白，并检查 衣壳抑制剂如何增强 MxB 活性。