Applied Biochemistry, Institute of Biotechnology, Technische Universität Berlin, 13355 Berlin, Germany.
Department of Infectious Diseases, Division of Viral Gastroenteritis and Hepatitis Pathogens and Enterovirus, Robert Koch Institute, 13353 Berlin, Germany.
Viruses. 2024 Aug 29;16(9):1378. doi: 10.3390/v16091378.
Hepatitis E virus (HEV) poses a significant global health threat, with an estimated 20 million infections occurring annually. Despite being a self-limiting illness, in most cases, HEV infection can lead to severe outcomes, particularly in pregnant women and individuals with pre-existing liver disease. In the absence of specific antiviral treatments, the exploration of RNAi interference (RNAi) as a targeted strategy provides valuable insights for urgently needed therapeutic interventions against Hepatitis E. We designed small interfering RNAs (siRNAs) against HEV, which target the helicase domain and the open reading frame 3 (ORF3). These target regions will reduce the risk of viral escape through mutations, as they belong to the most conserved regions in the HEV genome. The siRNAs targeting the ORF3 efficiently inhibited viral replication in A549 cells after HEV infection. Importantly, the siRNA was also highly effective at inhibiting HEV in the persistently infected A549 cell line, which provides a suitable model for chronic infection in patients. Furthermore, we showed that a 5' triphosphate modification on the siRNA sense strand activates the RIG-I receptor, a cytoplasmic pattern recognition receptor that recognizes viral RNA. Upon activation, RIG-I triggers a signaling cascade, effectively suppressing HEV replication. This dual-action strategy, combining the activation of the adaptive immune response and the inherent RNAi pathway, inhibits HEV replication successfully and may lead to the development of new therapies.
戊型肝炎病毒（HEV）对全球健康构成重大威胁，估计每年有 2000 万人感染。尽管 HEV 感染通常是自限性疾病，但在大多数情况下，它可能导致严重后果，特别是在孕妇和患有基础肝病的人群中。由于缺乏特异性抗病毒治疗方法，因此探索 RNA 干扰（RNAi）作为一种靶向策略，为急需的戊型肝炎治疗干预措施提供了有价值的见解。我们设计了针对 HEV 的小干扰 RNA（siRNA），靶向其解旋酶结构域和开放阅读框 3（ORF3）。这些靶标区域将降低通过突变发生病毒逃逸的风险，因为它们属于 HEV 基因组中最保守的区域。针对 ORF3 的 siRNA 在 HEV 感染后的 A549 细胞中有效地抑制了病毒复制。重要的是，该 siRNA 对持续感染的 A549 细胞系中的 HEV 也具有高度抑制作用，这为患者的慢性感染提供了合适的模型。此外，我们表明 siRNA 正义链的 5'三磷酸修饰激活了 RIG-I 受体，该受体是一种细胞质模式识别受体，可识别病毒 RNA。激活后，RIG-I 触发信号级联反应，有效地抑制了 HEV 复制。这种双重作用策略，结合了适应性免疫反应的激活和固有 RNAi 途径，成功抑制了 HEV 复制，并可能导致新疗法的开发。
