Effect of discodermin A, an antimicrobial peptide, on the cytoplasm membrane

The effects of discodermin A, an antimicrobial peptide extracted from sea sponge Discodermia kiiensis, on cell membranes were investigated using vascular smooth muscle cells and erythrocytes. At lower concentrations (0.1-3 microM), discodermin A increased muscle tension with an increase in intracell...

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Published inNihon yakurigaku zasshi Vol. 110 Suppl 1; p. 199P
Main Authors Sato, K, Horibe, K, Saito-Mitsui, M, Hori, M, Matsunaga, S, Fusetani, N, Ozaki, H, Karaki, H
Format Journal Article
LanguageJapanese
Published Japan 01.10.1997
Subjects
Amphibian Proteins
Animals
Antimicrobial Cationic Peptides
Calcium - metabolism
Cell Membrane Permeability - drug effects
Fura-2 - analogs & derivatives
Fura-2 - metabolism
Hemolysis - drug effects
In Vitro Techniques
Male
Muscle Contraction - drug effects
Muscle, Smooth, Vascular - drug effects
Muscle, Smooth, Vascular - metabolism
Peptides - isolation & purification
Peptides - pharmacology
Porifera - chemistry
Rabbits
Rats
Rats, Wistar
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Summary:The effects of discodermin A, an antimicrobial peptide extracted from sea sponge Discodermia kiiensis, on cell membranes were investigated using vascular smooth muscle cells and erythrocytes. At lower concentrations (0.1-3 microM), discodermin A increased muscle tension with an increase in intracellular free Ca2+ concentration ([Ca2+]i) indicated by the fluorescence of Ca2+ indicator, fura-PE3, in rat aortic smooth muscle. On the other hand, the higher concentration of discodermin A (10-30 microM) accelerated the leakage of loaded fura-PE3 from cells. In rabbit mesenteric artery treaded with discodermin A, addition of micromolar concentration of Ca2+ evoked contraction in the presence of ATP, suggesting that permeability of the membrane to Ca2+ and ATP is increased by discodermin A. Confocal fluorescence microscopy showed that discodermin A permeabilized the plasma membrane of A10 cells to fluorescent agents EthD-1 and the intracellular esterase coupled with another fluorescent agent calcein. Discodermin A also showed a hemolytic effect on rabbit erythrocytes, suggesting that discodermin A permitted transmembrane passage of hemoglobin. These results suggest that discodermin A form pores of different sizes on the cytoplasm membrane in concentration- and time-dependent manners. Discodermin A may be a saponin-like bioactive peptide.
ISSN:0015-5691