Biomedical Biotechnology Research Unit (BioBRU), Department of Biochemistry and Microbiology, Rhodes University, Makhanda 6139, South Africa.
School of Chemistry and Physics, University of Kwa-Zulu Natal, Durban, Westville 4001, South Africa.
ACS Infect Dis. 2024 Nov 8;10(11):3853-3867. doi: 10.1021/acsinfecdis.4c00429. Epub 2024 Oct 30.
The central role of the chaperome in maintaining cellular proteostasis has seen numerous viral families evolve to parasitically exploit host chaperones in their life cycle. The HSP90 chaperone protein and its cochaperone Hop have both individually been shown to be essential factors for Kaposi sarcoma-associated herpesvirus (KSHV) lytic replication. Given the fundamental regulatory role that protein-protein interactions (PPIs) play in cellular biology, we reasoned that disrupting the Hop-HSP90 PPI may provide a new host-based target for inhibiting KSHV lytic replication. This study expands upon a previous report of non-natural peptides, which were found to disrupt the association between the Hop domain and its interacting HSP90. Here, in addition to providing insight into the structure-activity relationships of PPI inhibition, we show disruption of the full-length Hop-HSP90 PPI. The inhibitory peptides selectively engaged the Hop domain in cell lysates and when tethered to a cell-penetrating peptide acted as noncytotoxic inhibitors of KSHV lytic replication by lowering the viral load, preventing the production of infectious virions, and reducing the expression of KSHV lytic genes. In addition to tentative evidence of Hop-HSP90 PPI as a much-needed target for KSHV drug discovery, this study represents an important step in understanding viral interactions with the host proteostasis machinery.
伴侣蛋白在维持细胞内蛋白质平衡方面发挥着核心作用，许多病毒家族在其生命周期中进化出寄生性利用宿主伴侣蛋白的机制。热休克蛋白 90（HSP90）伴侣蛋白及其共伴侣 Hop 均被单独证明是卡波济肉瘤相关疱疹病毒（KSHV）裂解复制的必需因素。鉴于蛋白质-蛋白质相互作用（PPIs）在细胞生物学中起着基本的调节作用，我们推断破坏 Hop-HSP90 PPI 可能为抑制 KSHV 裂解复制提供新的基于宿主的靶标。本研究扩展了之前关于非天然肽的报告，这些肽被发现可以破坏 Hop 结构域与其相互作用的 HSP90 之间的关联。在这里，除了深入了解 PPI 抑制的结构-活性关系外，我们还展示了全长 Hop-HSP90 PPI 的破坏。抑制肽在细胞裂解物中选择性地与 Hop 结构域结合，当与穿透细胞膜的肽（cell-penetrating peptide）连接时，通过降低病毒载量、阻止传染性病毒颗粒的产生以及降低 KSHV 裂解基因的表达，作为 KSHV 裂解复制的非细胞毒性抑制剂发挥作用。除了Hop-HSP90 PPI 作为 KSHV 药物发现急需靶标的初步证据外，本研究代表了理解病毒与宿主蛋白质平衡机制相互作用的重要一步。
