09. Februar 2015 Kiel researchers discover important transport mechanism in the malaria parasites

In collaboration with colleagues from the Bernhard Nocht Institute for Tropical Medicine, a research team at Christian-Albrechts University of Kiel (CAU) has identified a lactic acid transporter in the malaria parasite that has been sought for decades. As in the case of a human muscle that overacidifies if subjected to ongoing strain, the parasite also eliminates lactic acid as a waste product. It had previously not been known how exactly lactic acid is transported in the parasite. The current research results provide an important basis for future malaria medicines. The results are published in the international journal Nature Communications. Malaria parasites grow and multiply especially efficiently if sufficient quantities of glucose are available in the blood. When sugar is broken down, lactic acid is produced, which causes a reduced pH value as a by-product in the advanced stage of malaria. The structure of the responsible lactic acid transporter differs fundamentally from that of humans. This opens up important opportunities, says Janis Rambow from the Pharmaceutical Institute at the CAU and the lead author of the current study: "The lactic acid transporter plays a central role in the energy metabolism of the parasites and could serve extremely well as a point of attack for the development of urgently needed, new antimalarial drugs." In view of the structural differences, these could block the lactic acid transporters of malaria parasites, but not those of humans. It has been known since the 1940s that malaria parasites absorb glucose from the blood flow as their primary source of energy, and therefore excrete large quantities of lactic acid as toxic waste products. The corresponding glucose transporter of the parasite was finally described in 1999, but the lactic acid transporter remained undetected, possibly due to its unexpected structure. Transporters are proteins that transport substances to or from them. Professor Eric Beitz, project manager for the study, describes the coming steps of his research group: "The lactic acid transporter in the malaria parasite is a crucial mechanism for the parasite. As the next step, we want to develop molecules that can stop the excretion of lactic acid by the parasite." The team headed by Beitz hopes that such a development can form the basis for the development of new antimalarial medicines. Malaria is a tropical disease that is transmitted through the bite of female, infected mosquitoes. Worldwide, the diseases claims about one million lives a year; one half of these are children below the age of five. Their immune system is especially hard hit by the symptoms of recurrent fever, shivering, gastrointestinal complaints and cramp. The number of people suffering from malaria is estimated at 300 to 500 million worldwide; 90 percent of those affected live in Africa. Original publication: B. Wu, J. Rambow, S. Bock, J. Holm-Bertelsen, M. Wiechert, A. Blancke Soares, T. Spielmann und E. Beitz (2015): Identity of a Plasmodium lactate/H+ symporter structurally unrelated to human transporters. Nature Communications, dx.doi.org/10.1038/ncomms7284.