Inhibition of malaria parasite Plasmodium falciparum development by crotamine, a cell penetrating peptide from the snake venom

• Published in: Peptides (New York, N.Y. : 1980) Vol. 78; pp. 11 - 16
• Main Authors: El Chamy Maluf, S., Dal Mas, C., Oliveira, E.B., Melo, P.M., Carmona, A.K., Gazarini, M.L., Hayashi, M.A.F.
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01-04-2016
• Subjects: Acidic compartments; Acridine Orange - metabolism; Amino Acid Sequence; Animals; Antimalarial; Antimalarials - isolation & purification; Antimalarials - pharmacology; Biological Transport; Carbocyanines - chemistry; Cell-Penetrating Peptides - isolation & purification; Cell-Penetrating Peptides - pharmacology; Cells, Cultured; Chloroquine - pharmacology; Crotalid Venoms - isolation & purification; Crotalid Venoms - pharmacology; Crotalus - metabolism; Crotamine; Dose-Response Relationship, Drug; Erythrocytes; Erythrocytes - drug effects; Erythrocytes - parasitology; Fluorescence; Fluorescent Dyes - chemistry; Humans; Hydrogen-Ion Concentration - drug effects; Inhibitory Concentration 50; Malaria; Parasites; Peptide trafficking; Peptides; Plasmodium; Plasmodium falciparum; Plasmodium falciparum - drug effects; Plasmodium falciparum - growth & development; Plasmodium falciparum - metabolism; Polypeptides; Reduction; Snake Venoms - chemistry; Snakes; Staining and Labeling; Vacuoles - drug effects; Vacuoles - parasitology; Plasmodium; Antimalarial; RBC; Peptide trafficking; iRBC; Parasites; Cy3; AO; Crotamine; Acidic compartments
• ISSN: 0196-9781; 1873-5169
• DOI: 10.1016/j.peptides.2016.01.013

Schematic figure showing the preferential affinity of crotamine for P. falciparum infected erythrocytes, which may have increased negative charge exposure compared to the liquid net neutral surface of uninfected erythrocytes due to the extensive host cell remodeling mediated by parasites, for instance maure’s clefts, plasma membrane knobs complexes and TVN (tubovesicular network). The localization of crotamine in parasitophorous vacuole (PV), as well as in acidic digestive vacuole (DV) and nucleus are also indicated.
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•Crotamine is a cationic natural peptide with anti-plasmodial activity.•Crotamine has anti-plasmodial activity against Plasmodium falciparum.•Crotamine inhibits the development of the P. falciparum in a dose-dependent manner.•Crotamine was observed in the parasite nucleus and parasitophorous vacuole.•Crotamine may disrupt the parasite acidic compartments H+ homeostasis.
We show here that crotamine, a polypeptide from the South American rattlesnake venom with cell penetrating and selective anti-fungal and anti-tumoral properties, presents a potent anti-plasmodial activity in culture. Crotamine inhibits the development of the Plasmodium falciparum parasites in a dose-dependent manner [IC50 value of 1.87μM], and confocal microscopy analysis showed a selective internalization of fluorescent-labeled crotamine into P. falciparum infected erythrocytes, with no detectable fluorescence in uninfected healthy erythrocytes. In addition, similarly to the crotamine cytotoxic effects, the mechanism underlying the anti-plasmodial activity may involve the disruption of parasite acidic compartments H+ homeostasis. In fact, crotamine promoted a reduction of parasites organelle fluorescence loaded with the lysosomotropic fluorochrome acridine orange, in the same way as previously observed mammalian tumoral cells. Taken together, we show for the first time crotamine not only compromised the metabolism of the P. falciparum, but this toxin also inhibited the parasite growth. Therefore, we suggest this snake polypeptide as a promising lead molecule for the development of potential new molecules, namely peptidomimetics, with selectivity for infected erythrocytes and ability to inhibit the malaria infection by its natural affinity for acid vesicles.