Targeting the HMGB1 Pathway With Glycyrrhizic Acid and Amlexanox Attenuates RSV ‐Induced Injury and Viral Propagation

Respiratory syncytial virus (RSV) is the leading cause of acute respiratory infections globally, with particularly severe implications for infants and the elderly population. Despite the substantial burden on public health, effective therapeutic options for the treatment of RSV infections remain limited. The pathogenesis of RSV is characterized by complex inflammatory responses, while high-mobility group box 1 (HMGB1), a damage-associated molecular pattern protein, is known to play a role in amplifying inflammation. However, the specific role of HMGB1 in RSV infection has not been thoroughly investigated. This study aims to elucidate the role of HMGB1 in RSV replication and to evaluate its potential as a target for antiviral therapy. The interaction between the RSV nucleocapsid (N) protein and HMGB1 was demonstrated through co-immunoprecipitation and mass spectrometry. Knockdown or overexpression of HMGB1 by small interfering RNA or pCMV-HA-HMGB1 resulted in a significant reduction or induction in RSV replication in vitro, thereby confirming the critical role of HMGB1 in viral propagation. Moreover, structure-based molecular docking analyses identified glycyrrhizic acid (GA) and amlexanox (AMX) as high-affinity ligands for HMGB1. In cellular studies, both GA and AMX effectively inhibited RSV replication in a dose-dependent manner while selectively suppressing HMGB1's secretion to the cytoplasm or extracellular space from RSV-infected cells. AMX was found to down-regulate HMGB1 expression while GA did not. In experiments using lethal murine RSV infection models, treatment with GA and AMX significantly improved survival rates and reduced lung pathology. In conclusion, these findings suggest that HMGB1 is a promising therapeutic target for RSV infection and highlight GA and AMX as potential antiviral candidates that can modulate HMGB1-mediated immunopathology.