Le parasite Leishmania à l’ère de la post-génomique Studies on the parasite Leishmania in the post-genomic era

Résumé

Le parasite du genre Leishmania est, selon les espèces, responsable de différentes pathologies et représente une cause importante de morbidité et de mortalité en médecine humaine et vétérinaire. Ce parasite intracellulaire est transmis par l’intermédiaire de la mouche des sables chez un hôte vertébré, où, après différentiation, il se multiplie dans les macrophages. Le séquençage du génome de l’espèce Leishmania major est quasiment terminé. Ces données de séquences s’avèrent une source inestimable pour des études transcriptomiques et protéomiques qui permettent de mieux comprendre le processus de différentiation du parasite, son interaction avec la cellule hôte et sa capacité à résister aux traitements conventionnels.

Summary

Leishmania is a protozoan parasite responsible for considerable morbidity worldwide. The pathologies caused by Leishmania infections are varying with the species. The ongoing determination of the Leishmania major genome sequence represents a milestone for Leishmania research. We discuss here the use of transcriptomics and proteomics to accelerate our understanding of key processes related to Leishmania biology. These two techniques should be useful to find genes and proteins that are expressed in a stage-specific manner and examples of the use of such techniques are provided. Both approaches will complement each others. Indeed, while a number of stage-specific genes have increased stable RNA levels, an even larger subset of the Leishmania amastigote genes are regulated at the level of translation. The availability of the Leishmania genome should also permit important advances in finding species-specific genes that could explain different pathologies. Functional genomic and proteomic approaches should also be useful for understanding the mechanisms of drug resistance in the parasite. The availability of both the Leishmania genome and of its human host or of the mouse animal model will facilitate large scale studies and increase our understanding of host-pathogen interactions.