DISCOVERY OF NEW TSG101 INHIBITORS BLOCKING THE BUDDING OF EBOLA AND OTHER HIGHLY PATHOGENIC VIRUSES

Introduction: Emerging and re-emerging viruses pose a major and unpredictable threat to global health, highlighting the urgent need for effective broad-spectrum antiviral strategies. Targeting host cell factors commonly exploited by multiple viral families represents a promising approach to overcome the limitations of virus-specific therapies. Among these, tumor susceptibility gene 101 (TSG101), a key component of the endosomal sorting complexes required for transport (ESCRT) machinery, has emerged as an attractive target for host-directed antivirals. TSG101 plays a crucial role in the replication and budding of many enveloped viruses through interactions between its ubiquitin E2 variant (UEV) domain and viral late (L) domains. Aim: This study aimed to inhibit the protein-protein interaction (PPI) between the PTAP motif of viral L-domains and the UEV domain of TSG101 in order to develop novel host-directed broad-spectrum antiviral agents. Methods: Starting from the previously identified hit compound UEV-10, a series of simplified and more drug-like analogues was designed and synthesized. Their ability to inhibit the TSG101-UEV/L-domain interaction was evaluated using biophysical assays, including AlphaScreen and differential scanning fluorimetry (DSF), as well as cell-based assays such as bimolecular complementation (BiMC) and virus-like particle (VLP) assays. Results: The newly developed analogues effectively inhibited the TSG101-UEV/L-domain interaction in the low micromolar range. Selected compounds also demonstrated antiviral activity against highly pathogenic viruses, including Ebola, Marburg, and Nipah viruses. Conclusion: These findings underscore the critical role of TSG101 in viral budding and support the effectiveness of targeting the UEV/L-domain PPI as a host-directed antiviral strategy. This approach shows potential for developing broad-spectrum antivirals applicable across diverse viral families and may contribute to preparedness for future emerging viral threats.