Human Antimicrobial Peptide Isolated From Triatoma infestans Haemolymph, Trypanosoma cruzi-Transmitting Vector.

Laura Cristina Lima Diniz,Antonio Miranda,Pedro Ismael Da Silva Jr

doi:10.3389/fcimb.2018.00354

Laura Cristina Lima Diniz, Antonio Miranda + Show 1 more

Open Access

https://doi.org/10.3389/fcimb.2018.00354

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Abstract

The importance of antimicrobial peptides (AMPs) in relation to the survival of invertebrates is well known. The source and the mode of action on the insects' immune system of these molecules have been described from different perspectives. Insects produce their own AMPs as well as obtain these molecules from various sources, for example by absorption through the intestinal tract, as previously described for Boophilus microplus. Blood-sucking barber bug Triatoma infestans attracts social, economic and medical interest owing to its role in the transmission of Chagas disease. Despite new studies, descriptions of AMPs from this insect have remained elusive. Thus, the aims of this work were to characterize the antimicrobial potential of human fibrinopeptide A (FbPA) obtained from the T. infestans haemolymph and identify its natural source. Therefore, FbPA was isolated from the T. infestans haemolymph through liquid chromatography and identified by mass spectrometry. This peptide exhibited antimicrobial activity against Micrococcus luteus. Native FbPA from human blood and the synthetic FbPA also exhibited antimicrobial activity. The synthetic FbPA was conjugated with fluorescein isothiocyanate and offered to the insects. The haemolymph collected after 72 h exhibited fluorescence at the same wavelength as fluorescein isothiocyanate. Our experiments show that beyond intrinsic AMP production, T. infestans is able to co-opt molecules via internalization and may use them as AMPs for protection.

Highlights

The discovery of insect fossils that are approximately 400 million years old, such as those of Rhyniella praecursor and Rhyniognatha hirsti, demonstrates that insects were among the first animals to conquer the terrestrial habitat (Scourfield, 1940; Ross, 2017)
To confirm the results obtained with native human fibrinopeptide A (FbPA), human blood was processed (Methods section: Human Fibrinopeptide A Isolation) and the target fraction was isolated by HPLC (Figure 3); this fraction exhibited antimicrobial activity
Several studies have been performed aimed at a wider comprehension of the immune system of invertebrates, there are no consistent data about their adaptive immunity

Summary

Introduction

The discovery of insect fossils that are approximately 400 million years old, such as those of Rhyniella praecursor and Rhyniognatha hirsti, demonstrates that insects were among the first animals to conquer the terrestrial habitat (Scourfield, 1940; Ross, 2017). Their evolution represents a successful process represented by their earth-wide distribution, inhabiting every environment except marine habitats. The first is composed of enzymatic activation, the second is the fast and temporary production of antimicrobial peptides (AMPs), both belonging to the humoral response, and the third refers to phagocytic and encapsulation defenses, mediated specially by haemocytes (Hoffmann, 1995; Strand and Pech, 1995; Gillespie et al, 1997; Blandin and Levashina, 2004; Cerenius and Soderhall, 2004; Theopold et al, 2004; Irving et al, 2005; Strand, 2008; Pasupuleti et al, 2012)

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