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    Meningococcal Type IV pili recognize a specific sugar exposed on the human receptor CD147/Basigin to colonize human cells

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    A study of Bourdoulous team

    Meningococcal Type IV pili recognize a specific sugar exposed to colonize human cells

    The team of Dr Sandrine Bourdoulous shows that Neisseria meningitidis (meningoccocus), a bacterium responsible for meningitis and severe forms of sepsis (purpura fulminans) adheres to human endothelial cells by recognition via its type IV pili of a specific triantennary N-glycan exposed on the human receptor CD147/Basigin. This study, performed in collaboration with Dr Mathieu Coureuil (Institut Necker Enfants Malades, Paris) and Dr Catherine Robbe-Masselot (Unité de Glycobiologie Structurale et Fonctionnelle, Université Lille), has just been published in the journal PNAS.

     

    A large fraction of the microbial factors that facilitate the adherence of bacteria to host cells (also known as “adhesins”) display a lectin activity and bind to specific glycan regions on components of glycocalyx (coat at the surface of cell membranes). The wide structural diversity of carbohydrates allows many combinatorial possibilities for fine-tuning host-microbial interactions. It can provide relatively strong and species-specific recognition and confer the tropism of individual bacteria for particular host tissues. Detailed studies of the specificity of such microbial lectins can lead to the identification and synthesis of powerful inhibitors of adhesion that may form the basis for novel therapeutic agents to combat infectious diseases. However, due the structural complexity and functional diversity of the carbohydrates, characterization of the exact nature of the specific carbohydrate motifs recognized by microbial adhesins remains difficult. There have been only a few cases where human receptors of pathogenic adhesins have been described. In particular, little is known on the cellular targets for type IV pili. These attributes, which are one of the most widespread factors found in Gram-negative and Gram-positive bacteria, are key adhesive factor in numerous pathogenic and non-pathogenic bacteria. Despite evidences that they might behave as bacterial surface lectins, no characterization of the specific glycan determinants they might recognized on their host receptors has been achieved so far.

     

    In this study, the team of Dr Sandrine Bourdoulous, who investigates the pathophysiological of meningococcal invasive diseases, took advantage of the previous identification of CD147 as the human cell host receptor for meningococcal type IV pili enabling colonization of vascular cells and meninges by Neisseria meningitidis (Bernard et al, Nature Med 2014). Combining different approaches (lectin affinity methods, enzymatic procedure and mass spectrometry analysis), the researchers identified the complex sialylated tri-antennary LacNAc-containing N-glycan specifically recognized by meningococcal type IV pili. They further showed that glycan fucosylation determines the specificity of meningococcal adhesion to human CD147 receptor. Finally, they demonstrated that the specificity of type IV pilus interaction also resides in the amino acid sequence of the receptor.

     

    Legend: Adhesion of Neisseria meningitidis (meningococcus) to human endothelial cells relies on the interaction between type IV pili and the human receptor CD147. Type IV pili specifically recognize a triantennary sialylated poly-N-acetyllactosamine–containing N-glycan exposed on the membrane proximal glycosylation site of CD147.

     

     

     

    These results highlight a new degree of complexity in the recognition of host receptor by type IV pili, which might play a determinant role in both species-specific recognition and the tropism for particular host tissues by piliated bacteria.

    This study has been performed with the support of the Agence Nationale de la Recherche, Fondation pour la Recherche Médicale and the Université de Paris. 

     

    En savoir plus

    Receptor recognition by meningococcal type IV pili relies on a specific complex N-glycan. Le Guennec L, Virion Z, Bouzinba-Ségard H, Robbe-Masselot C, Léonard R, Nassif X, Bourdoulous S*, Coureuil M*. (*S.B. and M.C. contributed equally to this work). Proc Natl Acad Sci U S A. 2020 Jan 21. pii: 201919567. doi: 10.1073/pnas.191956711.

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