Blanc SVSE 6 - Blanc - SVSE 6 - Génomique, génétique, bioinformatique et biologie systémique

Systemic impact of Mtb protein O-mannosylation in survival and virulence: Structural and functional definition of the Mtb glyco-proteome. – TB GlycoPrOmics

Evaluation of the potential of the mycobacterial protein O mannosylation as new therapeutic target against Tuberculosis

Systemic impact of Mtb protein O-mannosylation in survival and virulence: Structural and functional definition of the Mtb glyco-proteome.

Search for new potential therapeutic targets against tuberculosis

Mycobacterium tuberculosis (Mtb) remains a major public health threat with two millions people dying from tuberculosis each year (1 death every 16 seconds) (1). The disease burden is worsened by the alarming emergence of Multi- or eXtensively drug resistant (M-/X-DR) Mtb strains which have unveiled the weakness of the existing therapeutic arsenal and pointed out the urgent need of a comprehensive understanding of the determinism of Mtb pathogenicity to develop novel target for alternative therapeutics to fight Mtb. We recently described Mtb manno-proteins as an emerging class of bacterial adhesins susceptible to contribute to Mtb infectiousness through interactions with the host innate immune system receptors for pathogen including the lung surfactant protein A (SP-A) or DC-SIGN considered as the preferential receptor used by mycobacteria to enter their target cells and to evade the host defense mechanisms. Moreover we have strong evidences that some of these glycoproteins are intimately involved in the processes that Mtb has developed to persist and grow up in human. However, to date only three such glycoproteins have been formally described in Mtb. Moreover these Mtb glycoproteins are totally dispensable for Mtb survival. Then these observations clearly suggest the existence of still unknown glycoproteins in Mtb which may contribute to its ability to survive in vivo constituting hence potential target for future antituberculous drugs. The present proposal aims to identify these glycoproteins and to define their roles in the survival and virulence of Mtb.

Protein glycosylation is currently acknowledged as of the most abundant and biologically significant post translational modifications with considerable effects on protein properties and biological activities. However several strategic bottlenecks still considerably limit the development of the related systematic “-omics” approaches, namely Glycomics and Glycoproteomics prejudicing the comprehensive analysis of biological roles of glycoproteins including in the host-pathogen interactions. Then our objective is to propose for the first time a comprehensive secreted glyco-proteome of Mtb exclusively based on glycopeptide identification and characterization. Interestingly this mannoproteome will be complementary to those previously established from lectin recognition experiment since it will be the first one based on direct MS evidences of protein mannosylation. In addition, glycopeptides identification should give us the opportunity to develop complementary approaches based on targeted MS methodologies (SRM, MRM) to analyse the conditional modulation of their glycosylation pattern by environmental stresses (mimicking host cell microenvironment).

Expected

the current Mtb Glyco-proteome definition project is not only of prime interest for its biological and applicative relevance but also represents an outstanding opportunity to explore and define optimized MS strategies and adapted bioinformatics resources for future collaborative glycoproteomics projects. This would represent a considerable asset in the highly competitive field of the protein Post-translational modifications functional insights.

Expected

Protein glycosylation is currently acknowledged as of the most abundant and biologically significant post translational modifications with considerable effects on protein properties and biological activities. Long time considered to be restricted to eukaryotes, protein O-mannosylation also occurs in some prokaryota, and in particular in the major human pathogen Mycobacterium tuberculosis (Mtb). With 1/3 world population infected and two millions deaths of tuberculosis each year, Mtb, is a major public health threat. One reason is that despite decades of effort, the molecular basis of the pathogenicity of Mtb is still poorly understood. Recently Mtb manno-proteins have emerged as new class of cell surface or secreted bacterial molecules able to interact with host innate immune system C-Type lectins (SP-A, SP-D, DC-SIGN, MMR) and to trigger a specific response which may also contribute to Mtb infectiousness. Moreover some of us have now strong evidences that some of these glycoproteins are intimately involved in the processes that Mtb has developed to persist and grow up in human. However, to date only three such glycoproteins have been formally described in Mtb. Moreover these Mtb glycoproteins are totally dispensable for Mtb survival. Then these observations clearly suggest the existence of still unknown glycoproteins in Mtb which may contribute to its ability to survive in vivo constituting hence potential target for future antituberculous drugs. The present proposal aims to identify these glycoproteins and to define their roles in the survival and virulence of Mtb. For this we propose an integrated approach combining glyco-proteomics for Mtb glycoproteins identification, genetic and in vivo assays to verify their involvement in Mtb ability to persist in vivo and finally a co-related quantitative proteomics and transcriptomics analysis to decipher their roles in Mtb physiology. In this aim Dr M. Rivière coordinator of the project, proposes to put together the outstanding expertise in their respective fields of the world renowned “Immunochemistry and Mycobacterial Glycoconjugates” group (headed by G. Puzo), “Proteomic and Mass Spectrometry of Biomolecules” group (leads by B.Monsarrat and O.Schiltz) and the “Molecular Pathogenicity of Mycobacteria” team (headed by C. Guilhot). Although challenging this project, is an outstanding opportunity to explore and set optimized MS strategies and large scale data analysis bioinformatics resources to decipher the role of pathogen’s mannosylated proteins in the host pathogen relationship at system level. We strongly believe that the respective conceptual and practical harnessing of these three teams in the up to date methodologies and approaches should constitute a determining advantage to tackle this biological system in its whole complexity. Finally we expect this project to afford new surrogate targets and glycosylating enzyme activity markers exploitable for setting on a high throughput screening test for inhibitors of high potential therapeutic value.

Project coordination

Michel RIVIÈRE (CENTRE NATIONAL DE LA RECHERCHE SCIENTIFIQUE - DELEGATION REGIONALE MIDI-PYRENEES) – Michel.Riviere@ipbs.fr

The author of this summary is the project coordinator, who is responsible for the content of this summary. The ANR declines any responsibility as for its contents.

Partner

CNRS CENTRE NATIONAL DE LA RECHERCHE SCIENTIFIQUE - DELEGATION REGIONALE MIDI-PYRENEES
CNRS CENTRE NATIONAL DE LA RECHERCHE SCIENTIFIQUE - DELEGATION REGIONALE MIDI-PYRENEES
IPBS CENTRE NATIONAL DE LA RECHERCHE SCIENTIFIQUE - DELEGATION REGIONALE MIDI-PYRENEES

Help of the ANR 527,000 euros
Beginning and duration of the scientific project: December 2011 - 48 Months

Useful links

Explorez notre base de projets financés

 

 

ANR makes available its datasets on funded projects, click here to find more.

Sign up for the latest news:
Subscribe to our newsletter