Repurposed doxepin targeting host AXL kinase to disrupt viral 2C-mediated immune evasion in Coxsackievirus B infection

Abstract

Coxsackievirus B (CVB) infections pose a significant clinical burden due to their association with severe diseases such as myocarditis and aseptic meningitis, and effective antiviral therapies remain an unmet medical need. Here, we investigated the potential of repurposing doxepin hydrochloride (DH), a tricyclic antidepressant, as an antiviral agent against CVB. Our in vitro and in vivo experiments demonstrated that DH significantly inhibits CVB replication. Mechanistically, we elucidated that DH targets the host AXL kinase, thereby inhibiting its phosphorylation of the viral 2C protein at tyrosine 162. This disruption of 2C phosphorylation abrogates CVB-induced suppression of the host IKKβ/NF-κB signaling pathway, leading to the restoration of innate immune responses and enhanced production of pro-inflammatory cytokines IL-1β and IL-6. Furthermore, our findings unveiled a novel immune evasion mechanism employed by CVB, wherein AXL kinase modulates viral replication by regulating host immune signaling. These results highlight AXL as a critical host factor in CVB infection and provide a strong rationale for considering DH as a potential host-targeted therapeutic strategy for CVB-associated diseases, particularly in the absence of specific antiviral agents.