Multienzyme-like active MnO2 nanozyme with ROS scavenging for inflammatory injury therapy induced by avian flavivirus through antiviral function.

Duck Tembusu virus (DTMUV) is an acute avian flavivirus that primarily infects poultry, mosquitoes, and some mammals including humans. The viral infection triggers reactive oxygen species (ROS) and inflammatory response that are crucial in mediating injury. Crafting multifunctional nanozymes that possess both ROS scavenging and anti-inflammatory activities presents formidable challenges. The study synthesized manganese dioxide cauliflowers (MnO₂ Cfs) endowed with multiple enzyme-like activities (analogous to SOD, CAT, and GPX) that effectively alleviated the injury induced by DTMUV both in vitro and in vivo. Remarkably, MnO₂ Cfs efficiently neutralized various ROS, encompassing hydrogen peroxide (H₂O₂), superoxide anion (O₂^·-) and hydroxyl radical (·OH). Our in vitro assessments showed that MnO₂ Cfs could alleviate cytopathic effects and modulate the innate immune response during DTMUV infection through their ROS scavenging and anti-inflammatory properties. In vivo experiments supported these findings, demonstrating that ducklings therapied by MnO₂ Cfs experienced alleviated injury during DTMUV infection. Importantly, MnO₂ Cfs also effectively inhibited DTMUV replication in both laboratory and field conditions. This study presents a novel strategy for nanozyme design, promising significant therapeutic potential for treating viral inflammatory diseases.