Conformational activation and disulfide exchange in HIV-1 Env induce cell-free lytic/fusogenic transformation and enhance infection.

IF 4 2区 医学 Q2 VIROLOGY
Journal of Virology Pub Date : 2025-03-18 Epub Date: 2025-02-06 DOI:10.1128/jvi.01471-24
Charles G Ang, Nadia L Hyatt, Giang Le Minh, Monisha Gupta, Manali Kadam, Philip J Hogg, Amos B Smith, Irwin M Chaiken
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引用次数: 0

Abstract

Disulfide exchange is underexplored as a mechanism influencing HIV-1 entry. Prior studies demonstrated that redox enzyme inhibition can prevent HIV-1 infection but with limited mechanistic explanation. We hypothesize that ligand-driven rearrangement ("conformational activation") enables enzyme-mediated disulfide exchange in Env residues ("disulfide trigger") that promotes fusion transformations, enhancing virus entry. We tested soluble CD4 and CD4-binding site entry inhibitors as conformational activators and the ubiquitous redox enzyme thioredoxin-1 (Trx1) as disulfide trigger. We found that combination treatment caused fusion-like Env transformation and pseudovirus lysis, independent of cells. Notably, only compounds associated with gp120 shedding caused lysis when paired with Trx1. In each case, lysis was prevented by adding the fusion inhibitor T20, demonstrating that six-helix bundle formation is required as in virus-cell fusion. In contrast to conformationally activating ligands, neither the ground state stabilizer BMS-806 with Trx1 nor Trx1 alone caused lysis. Order of addition experiments reinforced conformational activation/disulfide trigger as a sequential process, with virus/activator preincubation transiently enhancing lysis and virus/Trx1 preincubation reducing lysis. Lastly, addition of exogenous Trx1 to typical pseudovirus infections exhibited dose-dependent enhancement of infection. Altogether, these data support conformational activation and disulfide triggering as a mechanism that can induce and enhance the fusogenic transformation of Env.IMPORTANCEHIV remains a global epidemic despite effective anti-retroviral therapies (ART) that suppress viral replication. Damage from early-stage infection and immune cell depletion lingers, as ART enables only partial immune system recovery, making prevention of initial virus entry preferable. In this study, we investigate disulfide exchange and its facilitating conformational rearrangements as underexplored, but critical, events in the HIV entry process. The HIV envelope (Env) protein effects cell entry by conformational rearrangement and pore formation upon interaction with immune cell surface proteins, but this transformation can be induced by Env's conformational activation and disulfide exchange by redox enzymes, which then integrates into established processes of HIV entry. The significance of this research is in identifying Env's conformational activation as a mechanistic requirement for initiating fusion by triggering disulfide exchange. This will aid the development of novel preventative strategies against HIV entry, particularly in the context of HIV-enhanced inflammation and comorbidities with redox mechanisms.

HIV-1 Env的构象激活和二硫交换诱导无细胞裂解/融合转化并增强感染。
二硫交换作为一种影响HIV-1进入的机制尚未得到充分探讨。先前的研究表明,氧化还原酶抑制可以预防HIV-1感染,但机制解释有限。我们假设配体驱动的重排(“构象激活”)使酶介导的Env残基二硫化物交换(“二硫化物触发器”)能够促进融合转化,增强病毒进入。我们测试了可溶性CD4和CD4结合位点进入抑制剂作为构象激活剂和无处不在的氧化还原酶硫氧还蛋白-1 (Trx1)作为二硫化物触发剂。我们发现,联合治疗引起融合样Env转化和假病毒裂解,独立于细胞。值得注意的是,当与Trx1配对时,只有与gp120脱落相关的化合物引起裂解。在每种情况下,通过添加融合抑制剂T20可以阻止裂解,这表明在病毒-细胞融合中需要六螺旋束的形成。与构象激活配体相比,基态稳定剂BMS-806与Trx1或Trx1单独都不会引起裂解。加成实验的顺序强化了构象激活/二硫触发作为一个连续的过程,病毒/激活剂预孵育短暂地促进裂解,病毒/Trx1预孵育减少裂解。最后,在典型的假病毒感染中添加外源性Trx1表现出剂量依赖性的感染增强。综上所述,这些数据支持构象激活和二硫化物触发作为一种机制,可以诱导和增强Env的聚变转化。尽管有效的抗逆转录病毒疗法(ART)可以抑制病毒复制,但艾滋病毒仍然是一种全球性流行病。早期感染和免疫细胞耗竭造成的损害持续存在,因为抗逆转录病毒疗法只能使免疫系统部分恢复,因此预防最初的病毒侵入更为可取。在这项研究中,我们研究了二硫交换及其促进的构象重排作为HIV进入过程中未被充分探索但关键的事件。HIV包膜(Env)蛋白通过与免疫细胞表面蛋白相互作用时的构象重排和孔形成来影响细胞进入,但这种转化可以通过Env的构象激活和氧化还原酶的二硫交换来诱导,然后整合到既定的HIV进入过程中。本研究的意义在于确定了Env的构象激活是通过触发二硫交换来启动聚变的机制要求。这将有助于开发新的预防艾滋病毒进入的策略,特别是在艾滋病毒增强炎症和氧化还原机制合并症的背景下。
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来源期刊
Journal of Virology
Journal of Virology 医学-病毒学
CiteScore
10.10
自引率
7.40%
发文量
906
审稿时长
1 months
期刊介绍: Journal of Virology (JVI) explores the nature of the viruses of animals, archaea, bacteria, fungi, plants, and protozoa. We welcome papers on virion structure and assembly, viral genome replication and regulation of gene expression, genetic diversity and evolution, virus-cell interactions, cellular responses to infection, transformation and oncogenesis, gene delivery, viral pathogenesis and immunity, and vaccines and antiviral agents.
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