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This Article Full Text Full Text (PDF) Supplemental Data All Versions of this Article: fj.07-096081v1 22/6/1817    most recent Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Google Scholar Articles by Luque-Ortega, J. R. Articles by Rivas, L. PubMed PubMed Citation Articles by Luque-Ortega, J. R. Articles by Rivas, L.

Human antimicrobial peptide histatin 5 is a cell-penetrating peptide targeting mitochondrial ATP synthesis in Leishmania

Juan Román Luque-Ortega^*, Wim van't Hof, Enno C. I. Veerman, José M. Saugar^* and Luis Rivas^*,1

^* Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Cientificas, Madrid, Spain; and

Department of Oral Biochemistry, Academic Centre of Dentistry, Amsterdam, The Netherlands

¹Correspondence: Centro de Investigaciones Biológicas, CSIC, Ramiro de Maeztu 9, 28040-Madrid, Spain. E-mail: luis.rivas{at}cib.csic.es

Histatin 5 (Hst5) is a human salivary antimicrobial peptide that targets fungal mitochondria. In the human parasitic protozoa Leishmania, the mitochondrial ATP production is essential, as it lacks the bioenergetic switch between glycolysis and oxidative phosphorylation described in some yeasts. On these premises, Hst5 activity was assayed on both stages of its life cycle, promastigotes and amastigotes (LC₅₀=7.3 and 14.4 µM, respectively). In a further step, its lethal mechanism was studied. The main conclusions drawn were as follows: 1) Hst5 causes limited and temporary damage to the plasma membrane of the parasites, as assessed by electron microscopy, depolarization, and entrance of the vital dye SYTOX Green; 2) Hst5 translocates into the cytoplasm of Leishmania in an achiral receptor-independent manner with accumulation into the mitochondrion, as shown by confocal microscopy; and 3) Hst5 produces a bioenergetic collapse of the parasite, caused essentially by the decrease of mitochondrial ATP synthesis through inhibition of F₁F₀-ATPase, with subsequent fast ATP exhaustion. By using the Hst5 enantiomer, it was found that the key steps of its lethal mechanism involved no chiral recognition. Hst5 thus constitutes the first leishmanicidal peptide with a defined nonstereospecific intracellular target. The prospects of its development, by its own or as a carrier molecule for other leishmanicidal molecules, into a novel anti-Leishmania drug with a preferential subcellular accumulation are discussed.—Luque-Ortega, J. R., van’t Hof, W., Veerman, E. C. I., Saugar, J. M., Rivas, L. The human antimicrobial peptide histatin 5 is a cell-penetrating peptide targeting mitochondrial ATP synthesis in Leishmania.

Key Words: bioenergetics • ATP synthase • Trypanosomatidae • histidine-rich peptide