Claudine Belon1,2, Mariana Rosas Olvera1,2, Eric Vives3, Laurent Kremer4,5, Laila Gannoun-Zaki1,2, Anne-Béatrice Blanc-Potard1,2. 1. Laboratoire de Dynamique des Interactions Membranaires Normales et Pathologiques, Université de Montpellier, Place Eugène Bataillon, 34095 Montpellier Cedex 05, France. 2. CNRS, UMR5235, 34095 Montpellier Cedex 05, France. 3. Université de Montpellier, Montpellier, F-34090, France. 4. INSERM, DIMNP, CNRS-UMR5235, Montpellier, France. 5. Centre d'études d'agents Pathogènes et Biotechnologies pour la Santé (CPBS - FRE 3689), 1919 route de Mende, 34293 Montpellier, France.
Abstract
BACKGROUND: The MgtC virulence factor has been proposed as an attractive target for antivirulence strategies because it is shared by several important bacterial pathogens, including Salmonella enterica and Mycobacterium tuberculosis (Mtb). AIM: A natural antagonistic peptide, MgtR, which interacts with MgtC and modulates its stability, has been identified in Salmonella, and we investigated its efficiency to target MgtC in another pathogen. MATERIALS & METHODS: We evaluated the interaction between Salmonella MgtR peptide and the Mtb MgtC protein using an in vivo bacterial two-hybrid system and we addressed the effect of exogenously added synthetic MgtR and endogenously expressed peptide. RESULTS: MgtR peptide strongly interacted with Mtb MgtC protein and exogenously added synthetic MgtR peptide-reduced Mtb MgtC level and interfered with the dimerization of Mtb MgtC. Importantly, heterologous expression of MgtR in Mycobacterium bovis BCG resulted in increased phagocytosis and reduced intramacrophage survival. CONCLUSION: MgtR peptide can target Mtb MgtC protein and reduce mycobacterial macrophage resistance, thus providing a promising new scaffold for the development of antivirulence compounds.
BACKGROUND: The MgtC virulence factor has been proposed as an attractive target for antivirulence strategies because it is shared by several important bacterial pathogens, including Salmonella enterica and Mycobacterium tuberculosis (Mtb). AIM: A natural antagonistic peptide, MgtR, which interacts with MgtC and modulates its stability, has been identified in Salmonella, and we investigated its efficiency to target MgtC in another pathogen. MATERIALS & METHODS: We evaluated the interaction between Salmonella MgtR peptide and the Mtb MgtC protein using an in vivo bacterial two-hybrid system and we addressed the effect of exogenously added synthetic MgtR and endogenously expressed peptide. RESULTS: MgtR peptide strongly interacted with Mtb MgtC protein and exogenously added synthetic MgtR peptide-reduced Mtb MgtC level and interfered with the dimerization of Mtb MgtC. Importantly, heterologous expression of MgtR in Mycobacterium bovis BCG resulted in increased phagocytosis and reduced intramacrophage survival. CONCLUSION: MgtR peptide can target Mtb MgtC protein and reduce mycobacterial macrophage resistance, thus providing a promising new scaffold for the development of antivirulence compounds.