Downregulation of thioredoxin-like 1 contributes to miconazole's antiviral activity against West Nile virus.

Introduction: West Nile virus (WNV)-associated neurological diseases pose a global public health burden, yet no approved antiviral treatments are available. This is primarily due to the challenges of crossing the blood-brain barrier and the lengthy, costly process of drug development. Methods: High-throughput screening of a blood-brain barrier-penetrating FDA-approved compound library was performed to identify anti-WNV candidates in a neuronal cell infection model. Antiviral efficacy was further evaluated across different target cells and a range of flaviviruses, as well as in a mouse model of central nervous system (CNS) WNV infection. Stage-of-action analysis and mechanistic studies were conducted. Results: Miconazole emerged as a promising candidate with significant antiviral efficacy against multiple flaviviruses in different cell types. In the CNS infection mouse model, miconazole treatment reduced viral load in brain tissue and improved survival rates. The compound primarily inhibited viral replication, without affecting binding, internalization, or membrane fusion. Mechanistic studies suggested that this antiviral effect may be mediated through the downregulation of host protein thioredoxin-like 1 (TXNL1). Discussion: Our findings highlight miconazole as a promising candidate for repurposing in anti-flavivirus therapy and identify TXNL1 as a potential host target for the development of broad-spectrum antivirals.