Gomesin acts in the immune system and promotes myeloid differentiation and monocyte/macrophage activation in mouse

Endocytosis and the Participation of Glycosaminoglycans Are Important to the Mechanism of Cell Death Induced by β-Hairpin Antimicrobial Peptides

The cytotoxic mode of action of four antimicrobial peptides (AMPs) (gomesin, tachyplesin, protegrin, and polyphemusin) against a HeLa cell tumor model is discussed. A study of cell death by AMP stimulation revealed some similarities, including annexin-V externalization, reduction of mitochondrial potential, insensitivity against inhibitors of cell death, and membrane permeabilization. Evaluation of signaling proteins and gene expression that control cell death revealed wide variation in the responses to AMPs. However, the ability to cross cell membranes emerged as an important characteristic of AMP-dependent cell death, where endocytosis mediated by dynamin is a common mechanism. Furthermore, the affinity between AMPs and glycosaminoglycans (GAGs) and GAG participation in the cytotoxicity of AMPs were verified. The results show that, despite their primary and secondary structure homology, these peptides present different modes of action, but endocytosis and GAG participation are an important and common mechanism of cytotoxicity for β-hairpin peptides.

The Biological and Biophysical Properties of the Spider Peptide Gomesin

This review summarises the current knowledge of Gomesin (Gm), an 18-residue long, cationic anti-microbial peptide originally isolated from the haemocytes of the Brazilian tarantula Acanthoscurria gomesiana. The peptide shows potent cytotoxic activity against clinically relevant microbes including Gram-positive and Gram-negative bacteria, fungi, and parasites. In addition, Gm shows in-vitro and in-vivo anti-cancer activities against several human and murine cancers. The peptide exerts its cytotoxic activity by permeabilising cell membranes, but the underlying molecular mechanism of action is still unclear. Due to its potential as a therapeutic agent, the structure and membrane-binding properties, as well as the leakage and cytotoxic activities of Gm have been studied using a range of techniques. This review provides a summary of these studies, with a particular focus on biophysical characterisation studies of peptide variants that have attempted to establish a structure-activity relationship. Future studies are still needed to rationalise the binding affinity and cell-type-specific selectivity of Gm and its variants, while more pre-clinical studies are required to develop Gm into a therapeutically useful peptide.

Comparison of Cytotoxic Activity in Leukemic Lineages Reveals Important Features of β-Hairpin Antimicrobial Peptides

Several reports described different modes of cell death triggered by antimicrobial peptides (AMPs) due to direct effects on membrane disruption, and more recently by apoptosis and necrosis-like patterns. Cytotoxic curves of four β-hairpin AMPs (gomesin, protegrin, tachyplesin, and polyphemusin) were obtained from several human leukemic lineages and normal monocytes and Two cell lines were then selected based on their cytotoxic sensitivity. One was sensitive to AMPs (K562) and the other resistant (KG-1) and their effect compared between these lineages. Thus, these lineages were chosen to further investigate biological features related with their cytotoxicities to AMPs. Stimulation with AMPs produced cell death, with activation of caspase-3, in K562 lineage. Increase on the fluidity of plasmatic membrane by reducing cholesterol potentiated cytotoxicity of AMPs in both lineages. Quantification of internal and external gomesin binding to the cellular membrane of both K562 and KG-1 cells showed that more peptide is accumulated inside of K562 cells. Additionally, evaluation of multi-drug resistant pumps activity showed that KG-1 has more activity than K562 lineage. A comparison of intrinsic gene patterns showed great differences between K562 and KG-1, but stimulation with gomesin promoted few changes in gene expression patterns. Differences in internalization process through the plasma membrane, multidrug resistance pumps activity, and gene expression pattern are important features to AMPs regulated cell death. J. Cell. Biochem. 118: 1764-1773, 2017. © 2016 Wiley Periodicals, Inc.