Two Tachykinin-Related Peptides with Antimicrobial Activity Isolated from Triatoma infestans Hemolymph

Abstract

Antimicrobial peptides and proteins (AMPs) are molecules that can interact with microbial cells and lead to membrane disruption or intracellular molecule interactions and death. Several molecules with antimicrobial effects also present other biological activities. One such protein group representing the duplicity of activities is the tachykinin family. Tachykinins (TKs) form a family of neuropeptides in vertebrates with a consensus C-terminal region (F-X-G-Y-R-NH2). Invertebrate TKs and TK-related peptides (TKRPs) are subfamilies found in invertebrates that present high homology with TKs and have similar biological effects. Several of these molecules have already been described but reports of TKRP in Hemiptera species are limited. By analyzing the Triatoma infestans hemolymph by reversed-phase high-performance liquid chromatography, biological assays, and mass spectrometry, two antimicrobial molecules were isolated and identified as TKRPs, which we named as TRP1-TINF and TRP2-TINF (tachykinin-related peptides I and II from T. infestans). TRP1-TINF is a random secondary structure peptide with 9 amino acid residues. It is susceptible to aminopeptidases degradation and is active mainly against Micrococcus luteus (32 μM). TRP2-TINF is a 10-amino acid peptide with a 310 helix secondary structure and is susceptible to carboxypeptidases degradation. It has major antimicrobial activity against both Pseudomonas aeruginosa and Escherichia coli (45 μM). Neither molecule is toxic to human erythrocytes and both present minor toxicity toward Vero cells at a concentration of 1000 μM. As the first description of TKRPs with antimicrobial activity in T. infestans, this work contributes to the wider comprehension of the insects’ physiology and describes pharmacological relevant molecules.

Tachykinin-related peptides modulate immune-gene expression in the mealworm beetle Tenebrio molitor L.

“…Moreover, the time-dependent action of Tenmo-TRP-7 can be explained by a general mode of action of neuropeptides. Based on the research by Diniz et al 89 conducted on the TRPs identified in Triatoma infestans, the time to the full degradation of TRPs oscillated at approximately 120 min. The results in vertebrate TKs, especially SP, are comparable to those obtained in research on insects 90 .…”

How a tarantula can help treat infections:Avicularia juruensis’s theraphotoxins that also act as antimicrobials

“…2016), Tityus serrulatus (de Jesus Oliveira et al . 2019), and Triatoma infestans (Diniz et al . 2020), for example.…”

Hemolymph of triatomines presents fungistatic activity against Cryptococcus neoformans and improves macrophage function through MCP-I/TNF-α increase

“…Regarding triatomines, one of the best-studied species concerning the production of microbicidal molecules is Triatoma infestans. This triatomine can produce proteins from the tachykinin family in its hemolymph presenting bactericidal activity against Micrococcus luteus, P. aeruginosa and Escherichia coli [41]. It has been already described that fibrinopeptide A obtained from the T. infestans hemolymph, exhibited antimicrobial activity against fungi, including C. neoformans [42]; beforehand, antifungal compounds have been isolated from other species as the fly Lucilia sericata, and the G. mellonella moth larvae [43,44].…”