Purification and Characterization of a Leishmania Mitogen Activated Protein Kinase : A Potentially New Anti-Parasitic Drug Target

Synthetic inhibitors of the human mitogen activated protein kinase, p38 MAPK may represent a new class of anti-parasitic agents. p38 MAPK inhibitors have been shown to inhibit replication of Toxoplasma gondii (T.gondii), the causative agent of taxoplasmosis, in vitro and in vivo. Inhibition of parasite replication was due to the inhibition of a T.gondii p38 MAPK homolog called tgmapk-1. Other parasites have MAPKs homologous to tgmapk-1 and these MAPKs may represent novel drug targets for new therapeutics in treating parasitic diseases. We have focused on a MAPK from, Leishmania mexicana (L.mexicana), the causative agent for one form of leishmaniasis. The kinase, LmxMPKl, shares sequence homology to both human p38 MAPK and tgmapk-1. It has been observed that a deletion mutation in the gene encoding LmxMPKl renders the kinase inactive and the parasite unable to establish disease in a murine model of this infection therefore, validating LmxMPKl as a potential parasite MAPK therapeutic target. For my thesis research, I have expressed recombinant LmxMPKl in mammalian HEK 293T cells and demonstrated basal kinase activity. A variety of kinase inhibitors were evaluated for inhibition of LmxMPKl activity and one, the p38 MAPK inhibitor, BIRB 796, was found to inhibit the enzyme. These results indicate that BIRB 796 may inhibit Leishmania replication through inhibition of LmxMPKl activity and therefore represent a new anti-parasitic drug