Pan Baolong, Mountford Simon J, Kiso Maki, Anderson Danielle E, Papadakis Georgina, Jarman Kate E, Tilmanis Danielle R, Maher Belinda, Tran Thomas, Shortt Jake, Yamayoshi Seiya, Kawaoka Yoshihiro, Thompson Philip E, Greenall Sam A, Warner Nadia
Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Australia.
Department of Chemistry, Massachusetts Institute of Technology, Cambridge, USA.
Commun Med (Lond). 2025 Apr 26;5(1):140. doi: 10.1038/s43856-025-00863-1.
Effective antiviral therapy is lacking for most viral infections, and when available, is frequently compromised by the selection of resistance. Targeted protein degraders could provide an avenue to more effective antivirals, able to overcome the selection of resistance. The aim of this study was to determine whether adaptation of SARS-CoV-2 main protease (Mpro, also described as chymotrypsin-like protease (3CL) or non-structural protein 5 (Nsp5)) inhibitors into degraders leads to increased antiviral activity, including activity against resistant virus.
We adapted the clinically approved Mpro inhibitor nirmatrelvir into a panel of degraders. Size-matched non-degrading controls were also synthesised to discriminate degradation activity from inhibition activity. Degrader activity was confirmed using an inducible Mpro-HiBiT tag expressing cell line. Antiviral activity against both wildtype and nirmatrelvir-resistant virus was performed using infection of susceptible cell lines.
Here we show three compounds, derived from nirmatrelvir and utilising VHL or IAP ubiquitin ligase recruiters, capable of degrading Mpro protein in a concentration, time and proteasome dependent fashion. These compounds also degrade nirmatrelvir-resistant mutant Mpro. The most potent of these compounds possesses enhanced antiviral activity against multiple wildtype SARS-CoV-2 strains and nirmatrelvir-resistant strains compared to non-degrading controls.
This work demonstrates the feasibility of generating degraders from viral protein inhibitors, and confirms that degraders possess higher antiviral potency and activity against resistant virus, compared to size matched non-degrading enzymatic inhibitors. These findings further support the development of targeted viral protein degraders as antiviral drugs, which may lead to more effective antiviral therapies for the future.
大多数病毒感染缺乏有效的抗病毒治疗方法，即便有可用的治疗方法，也常常因耐药性的产生而受到影响。靶向蛋白降解剂可能为开发更有效的抗病毒药物提供途径，有望克服耐药性问题。本研究的目的是确定将严重急性呼吸综合征冠状病毒2（SARS-CoV-2）主要蛋白酶（Mpro，也称为类胰凝乳蛋白酶样蛋白酶（3CL）或非结构蛋白5（Nsp5））抑制剂改造为降解剂是否会增强抗病毒活性，包括对耐药病毒的活性。
我们将临床批准的Mpro抑制剂奈玛特韦改造为一组降解剂。还合成了大小匹配的非降解对照物，以区分降解活性和抑制活性。使用可诱导表达Mpro-HiBiT标签的细胞系确认降解剂活性。通过感染易感细胞系，对野生型和奈玛特韦耐药病毒进行抗病毒活性检测。
我们在此展示了三种源自奈玛特韦并利用VHL或IAP泛素连接酶招募剂的化合物，它们能够以浓度、时间和蛋白酶体依赖性方式降解Mpro蛋白。这些化合物还能降解对奈玛特韦耐药的突变型Mpro。与非降解对照物相比，这些化合物中最有效的一种对多种野生型SARS-CoV-2毒株和奈玛特韦耐药毒株具有增强的抗病毒活性。
这项工作证明了从病毒蛋白抑制剂生成降解剂的可行性，并证实与大小匹配的非降解酶抑制剂相比，降解剂对耐药病毒具有更高的抗病毒效力和活性。这些发现进一步支持了将靶向病毒蛋白降解剂开发为抗病毒药物，这可能为未来带来更有效的抗病毒治疗方法。
