Glycosphingolipids in Plasmodium falciparum. Presence of an active glusylceramide synthase

S. COUTO, ALICIA; CAROLINA CAFFARO,; L. UHRIG, MARIA; MASAE NISHIOKA,; HIROSHI NONAMI,; E. KIMURA,; J. PERES, V.; M. KATZIN, ANDRES; ERRA BALSELLS, ROSA

EUROPEAN JOURNAL OF BIOCHEMISTRY

Blackwell Publishing Ltd.

Lugar: Londres; Año: 2004 vol. 271 p. 2204 - 2214

0014-2956

Summary   Malaria remains a major health problem, especially in tropical and subtropical regions of the world, thus, developing new antimalarial drugs constitutes an urgent challenge. Lipid metabolism has been attracting a lot of attention as application for malaria chemoterapeutic purposes in the last years. However, little is known about glycosphingolipid biosynthesis in Plasmodium falciparum. In this report we describe for the first time, the presence of an active glucosylceramide synthase in the intraerythrocytic stages of the parasite. Two different experiments, using UDP-[14C]glucose as donor with ceramides as acceptors or UDP-glucose as donor and fluorescent ceramides (BODIPY-ceramides) as acceptors were performed. In both cases, we found the parasite enzyme was able to glycosylate only dihydroceramide. The enzyme activity could be inhibited in vitro with low concentrations of DL-Threo-phenyl-2-palmitoylamino-3-morpholino-1-propanol (PPMP). In addition, de novo biosynthesis of glycosphingolipids was shown by metabolic incorporation of [14C]palmitic acid and [14C]glucose in the three intraerythrocytic stages of the parasite.  The structure of the components of ceramide, monohexosylceramide, and  trihexosylceramide and tetrahexosylceramide fractions were analysed by UV-MALDI-TOF mass spectrometry. When PPMP was tried in parasite cultures, a correlation between arrest of parasite growth and inhibition of glycosphingolipid biosynthesis was observed. The particular substrate specificity of the malarial glucosylceramide synthase must be added to the already known unique and amazing features of P. falciparum lipid metabolism, therefore this enzyme might represent a new attractive target for malarial chemotherapy.