A screening pipeline identifies a broad-spectrum inhibitor of bacterial AB toxins with cross protection against influenza A virus H1N1 and SARS-CoV-2

Wu, Yu; Mahtal, Nassim; Swistak, Léa; Sagadiev, Sara; Acharya, Mridu; Demeret, Caroline; van der Werf, Sylvie; Guivel-Benhassine, Florence; Schwartz, Olivier; Petracchini, Serena; Mettouchi, Amel; Paillares, Eléa; Caramelle, Lucie; Couvineau, Pierre; Thai, Robert; Barbe, Peggy; Keck, Mathilde; Brodin, Priscille; Machelart, Arnaud; Sencio, Valentin; Trottein, François; Sachse, Martin; Chicanne, Gaëtan; Payrastre, Bernard; Ville, Florian; Kreis, Victor; Popoff, Michel-Robert; Johannes, Ludger; Cintrat, Jean-Christophe; Barbier, Julien; Gillet, Daniel; Lemichez, Emmanuel

A challenge for the development of host-targeted anti-infectives against a large spectrum of AB-like toxin-producing bacteria encompasses the identification of chemical compounds corrupting toxin transport through both endolysosomal and retrograde pathways. Here, we performed a high-throughput screening of small chemical compounds blocking active Rac1 proteasomal degradation triggered by the Cytotoxic Necrotizing Factor-1 (CNF1) toxin, followed by orthogonal screens against two AB toxins hijacking defined endolysosomal (Diphtheria toxin) or retrograde (Shiga-like toxin 1) pathways to intoxicate cells. This led to the identification of the molecule N-(3,3-diphenylpropyl)-1-propyl-4-piperidinamine, referred to as C910. This compound induces the swelling of EEA1-positive early endosomes, in absence of PIKfyve kinase inhibition, and disturbs the trafficking of CNF1 and the B-subunit of Shiga toxin along the endolysosomal or retrograde pathways, respectively. Together, we show that C910 protects cells against 8 bacterial AB toxins including large clostridial glucosylating toxins from Clostridium difficile. Of interest, C910 also reduced viral infection in vitro including influenza A virus subtype H1N1 and SARS-CoV-2. Moreover, parenteral administration of C910 to the mice resulted in its accumulation in lung tissues and reduced lethal influenza infection.