Transcriptional suppression of antiviral immune responses by HIV-1 Vpu

HIV-1 Vpu 转录抑制抗病毒免疫反应

• 批准号: 404687549
• 负责人: Dr. Simon Langer
• 金额: --
• 依托单位: Sanford Burnham Prebys Medical Discovery Institute
• 依托单位国家: 德国
• 项目类别: Research Fellowships
• 财政年份: 2018
• 资助国家: 德国
• 起止时间: 2017-12-31 至 2018-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/404687549?language=en
• 关键词: Transcriptional; suppression; antiviral; immune; responses

The Human immunodeficiency virus 1 (HIV-1) is the causative agent of the acquired immunodeficiency syndrome (AIDS) and has infected more than 70 million people worldwide. Although humans are equipped with a variety of intrinsic, innate, and adaptive antiviral immune responses, HIV-1 has evolved sophisticated evasion strategies. Many of these strategies involve the viral accessory proteins Vpu, Nef, Vif and Vpr, which interfere with host factors to ensure efficient viral replication in vivo. While direct counteraction mechanisms have been investigated in detail, relatively little is known about transcriptional regulation, despite the fact that the latter may exert global effects on immune activation. As chronic immune activation is an important driver of disease progression in HIV infected individuals, a better understanding of how viral factors modulate host cell transcription will not only increase our understanding of the determinants of AIDS progression, but may ultimately also result in the identification of novel targets for therapy and prevention. The proposed projects focuses on the modulation of immune activation by the viral protein Vpu. Vpu was shown to efficiently block activation of the transcription factor NF-κB, a key regulator of innate and adaptive immune responses. I therefore hypothesize that Vpu is a potent transcriptional suppressor of antiviral immune responses. Notably, NF-κB activation levels also determine expression of HIV-1 genes and thus play an important role in viral latency and reactivation. I would therefore like to investigate the impact of NF-κB counteraction on immune activation and viral replication by combining different leading-edge systems biology approaches. First, I will perform next generation RNA-sequencing of primary CD4+ T cells infected with primary HIV-1 isolates to decipher the effects of HIV-1 Vpu on cellular gene expression, with a specific focus on genes involved in antiviral immune signaling. Second, I will use two innovative proteomics approaches to determine the global effects of Vpu on protein ubiquitination and degradation in order to identify novel cellular factors that are targeted by Vpu and elucidate the mechanisms underlying Vpu-mediated inhibition of NF-κB. Eventually, the identified hits will be validated and their relevance for immune activation, transcriptional regulation and viral replication will be tested. The results of this study will not only provide important insights into the factors determining immune activation and thus progression to AIDS, but may also advance current therapeutic approaches, in which NF-κB is targeted to reactivate and eliminate HIV-1 from latent reservoirs. In summary, this proposal aims at characterizing a unique pathway by which HIV-1 suppresses the antiviral immune response.

人类免疫缺陷病毒1（HIV-1）是获得性免疫缺陷综合征（AIDS）的病原体，在全世界感染了7000多万人。尽管人类具有多种内在、先天和适应性抗病毒免疫反应，但HIV-1已经进化出复杂的逃避策略。这些策略中的许多涉及病毒辅助蛋白Vpu、Nef、Vif和Vpr，其干扰宿主因子以确保体内有效的病毒复制。虽然已经详细研究了直接的对抗机制，但对转录调控知之甚少，尽管后者可能对免疫激活产生全局影响。由于慢性免疫激活是HIV感染者疾病进展的重要驱动因素，因此更好地了解病毒因子如何调节宿主细胞转录不仅会增加我们对艾滋病进展决定因素的理解，而且最终还可能导致识别治疗和预防的新靶点。拟议项目的重点是通过病毒蛋白Vpu调节免疫激活。Vpu显示出有效地阻断转录因子NF-κB的活化，NF-κ B是先天性和适应性免疫应答的关键调节因子。因此，我假设Vpu是一种有效的抗病毒免疫反应的转录抑制因子。值得注意的是，NF-κB活化水平也决定了HIV-1基因的表达，因此在病毒潜伏期和再活化中起重要作用。因此，我想通过结合不同的前沿系统生物学方法来研究NF-κB对抗免疫激活和病毒复制的影响。首先，我将对感染了HIV-1分离株的原代CD 4 + T细胞进行下一代RNA测序，以破译HIV-1 Vpu对细胞基因表达的影响，特别关注参与抗病毒免疫信号传导的基因。其次，我将使用两种创新的蛋白质组学方法来确定Vpu对蛋白质泛素化和降解的整体影响，以确定Vpu靶向的新细胞因子，并阐明Vpu介导的NF-κB抑制的机制。最终，将验证所识别的命中，并测试其与免疫激活、转录调节和病毒复制的相关性。这项研究的结果不仅将提供重要的见解，确定免疫激活的因素，从而发展到艾滋病，但也可能推进目前的治疗方法，其中NF-κB的目标是重新激活和消除潜伏水库的HIV-1。总之，该提案旨在表征HIV-1抑制抗病毒免疫应答的独特途径。