Study summary · research use only
Chemotactic activities of vasoactive intestinal peptide, neuropeptide Y and substance P in Leishmania braziliensis
Plain-language summary
Paraphrased from the published abstract below — not a verdict on whether anything works.
This in vitro study (species not specified) examined effects of the neuropeptides vasoactive intestinal peptide (VIP), neuropeptide Y (NPY), and substance P (SP) on migration of the parasite Leishmania (Viannia) braziliensis, and the effect of SP on Leishmania-macrophage interaction. The abstract reports that VIP (10-10 M) and NPY (10-9 M) were chemorepellent to the parasites while SP (10-8 M) produced a chemoattractant response; SP did not affect macrophage viability but decreased promastigote adherence to macrophages, an effect blocked by [D-Pro 2, D-Trp7,9]-Substance P (10-6 M). The chemorepellent effects of VIP and NPY were reported to be impaired by their corresponding receptor antagonists.
Abstract
Cell-cell interaction and active migration (and invasion) of parasites into skin host-cell(s) are key steps for successful infection by Leishmania. Chemotaxis constitutes a primordial chapter of Leishmania-host cell interaction, potentially modulated by neuropeptides released into the skin due, for example, to the noxious stimuli represented by the insect bite. Herein we have evaluated in vitro the effect of sensory (Substance P, SP) and autonomic (Vasoactive Intestinal Peptide, VIP, and Neuropeptide Y, NPY) neuropeptides on parasite taxis, and investigated the potential modulatory effect of SP on Leishmania (Viannia) braziliensis-macrophage interaction. We demonstrated that VIP (10-10 M) and NPY (10-9 M) are chemorepellent to the parasites, while SP (10-8 M) produces a chemoattractant response. SP did not affect macrophage viability but seems to impair parasite-macrophage interaction as it decreased promastigote adherence to macrophages. As this effect is blocked by ([D-Pro 2, D-Trp7,9]-Substance P (10-6 M), the observed action may be mediated by neurokinin-1 (NK1) transmembrane receptors. VIP and NPY repellent chemotactic effect is impaired by their corresponding receptor antagonists. Additionally, they suggest that SP may be a key molecule to guide promastigote migration towards, and interaction, with dendritic cells and macrophage host cells.
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