New drug targets for tropical disease

Research lead

By comparing the genomes of three parasite species that cause the devastating tropical disease Leishmaniasis, a consortium of UK scientists has identified a small number of genes that are targets for drug discovery. Leishmaniasis affects about two million people and new treatments are desperately needed.

The researchers compared the genomes of L. infantum and L. braziliensis, which cause life-threatening forms of the disease, with L. major, which causes a less severe form. Despite the major differences in disease type, only 200 out of more than 8,000 genes present in each genome were found to be differentially distributed between the three species. The researchers say this exceptionally small variation in gene content has given new insights into those processes that may determine disease severity in humans.

“Identifying factors that allow three closely related organisms to cause vastly different clinical outcomes is a major quest for researchers and in this study we have narrowed the search to a number that can be realistically studied,” commented Matt Berriman, one of the researchers from the Wellcome Trust Sanger Institute.

The researchers found only five genes in the L. major genome for which no trace could be found in the other two species.

The degree of similarity between these species was unexpected, and implies that only a few genes are important in determining the severity and type of disease that develops after infection.

“The genome sequences have given us a short-cut to a small number of largely novel genes,” said Chris Peacock, another researcher involved. “Given their lack of similarity to human genes, they present a limited repertoire of potential targets for drug and vaccine development allowing researchers to optimise the use of limited resources.”