Targeted Degradation of HCV Polymerase by GalNAc-Conjugated ApTACs for Pan-Genotypic Antiviral Therapy with High Resistance Barriers

Hepatitis C virus (HCV) infection is a major cause of chronic liver disease. Although interferon-free direct-acting antivirals have led to significant advancements in the treatment of HCV infection, the high genetic variability of the virus and the emergence of acquired drug resistance pose potential threats to their effectiveness. In this study, we develop a broad-spectrum aptamer-based proteolysis targeting chimera, designated dNS5B, which effectively degrades both pan-genotypic NS5B polymerase and drug-resistant mutants through ubiquitin proteasome system. To achieve hepatocyte-specific uptake, we further develop Gal-dNS5B by coupling the dNS5B with a trivalent N-acetylgalactosamine (tri-GalNAc), a ligand for the liver-specific asialoglycoprotein receptor. Gal-dNS5B exclusively accumulates in hepatocytes and suppresses HCV replication by degrading NS5B. Collectively, our research lays the groundwork for a scalable strategy in the development of antiviral medications aimed at addressing current and future challenges posed by hepatitis viruses and other re-emerging viral pandemics.

丙型肝炎病毒（Hepatitis C virus, HCV）感染是慢性肝脏疾病的主要致病原因之一。尽管无干扰素直接作用抗病毒药物已在HCV感染的临床治疗中取得显著进展，但该病毒极高的遗传变异性与获得性耐药突变的出现，仍对其治疗效果构成潜在威胁。本研究开发了一种基于适配体的广谱蛋白水解靶向嵌合体，命名为dNS5B。该嵌合体可通过泛素-蛋白酶体系统，有效降解泛基因型NS5B聚合酶及各类耐药突变体。为实现肝细胞特异性摄取，我们将dNS5B与三价N-乙酰半乳糖胺（tri-GalNAc）偶联，进一步构建得到Gal-dNS5B；其中三价N-乙酰半乳糖胺是肝脏特异性去唾液酸糖蛋白受体的配体。Gal-dNS5B可特异性富集于肝细胞内，并通过降解NS5B蛋白抑制HCV复制。综上，本研究为开发抗病毒药物提供了可规模化推广的策略框架，有望应对肝炎病毒及其他重新出现的病毒性大流行所带来的当前与未来挑战。