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.

项目摘要 虽然未经治疗的艾滋病毒/艾滋病感染是致命的，但人类仍然有一系列强大的先天抗病毒反应 在传播和病毒反弹过程中帮助抑制复制并对病毒施加强大的选择性压力 ART中断后。这些观察结果表明，先天免疫反应可能具有治疗价值，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必须通过这种先天的 免疫传感器和限制。项目2的研究，细胞防御艾滋病毒，将重建和表征 在病毒生命周期的前半期发生的细胞先天免疫感应和HIV-1限制机制。 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cryoEM结构上， hSERINC 3，以及我们发现限制性SERINC是非特异性磷脂乱序酶， 磷脂酰丝氨酸（PS）不对称性增强抗病毒作用。我们假设丝氨酸蛋白酶抑制剂通过改变 病毒体脂质双层的天然不对称性。我们建议确定丝氨酸蛋白酶如何翻转脂质，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 我们发现，HIV-1衣壳抑制剂可以促进先天性信号传导， 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 逆转录的检测，2）帽结合因子如PQBP 1如何有助于骨髓中的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 活动，以及5）如何产生的下游反应限制HIV-1感染。 目标3（TRIM限制）的研究将遵循我们的观察，即TRIM 5蛋白在周围形成六边形笼。 HIV-1病毒衣壳本目标中的实验旨在填补我们对病毒的理解中的基本空白。 抑制和信号传导过程遵循这一初始TRIM 5识别步骤，并发现宿主辅因子 促进或调节TRIM 5限制。 目标4（其他限制的重建）的研究将建立在我们重建SAMHD 1和APOBEC 3G的能力之上 限制复制HIV-1核心在体外，我们现在提出重建MxB限制。这些重组 反应将用于填补我们对限制机制，辅因子和调节的理解中的空白，并检查 衣壳抑制剂如何增强MxB活性。