Lutzomyia longipalpis Antimicrobial Peptides: Differential Expression during Development and Potential Involvement in Vector Interaction with Microbiota and Leishmania.

Erich Loza Telleria,Yara Maria Traub-Csekö,Tereza Leštinová,Bruno Tinoco-Nunes,André Nóbrega Pitaluga,Petr Volf,Antonio Jorge Tempone,Lívia Monteiro De Avellar

doi:10.3390/microorganisms9061271

Erich Loza Telleria, Yara Maria Traub-Csekö + Show 6 more

Open Access

https://doi.org/10.3390/microorganisms9061271

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Journal: Microorganisms	Publication Date: Jun 11, 2021
Citations: 12	License type: CC BY 4.0

Affiliation: Fundação Oswaldo Cruz, Charles University

Abstract

Antimicrobial peptides (AMPs) are produced to control bacteria, fungi, protozoa, and other infectious agents. Sand fly larvae develop and feed on a microbe-rich substrate, and the hematophagous females are exposed to additional pathogens. We focused on understanding the role of the AMPs attacin (Att), cecropin (Cec), and four defensins (Def1, Def2, Def3, and Def4) in Lutzomyia longipalpis, the main vector of visceral leishmaniasis in the Americas. Larvae and adults were collected under different feeding regimens, in addition to females artificially infected by Leishmania infantum. AMPs’ gene expression was assessed by qPCR, and gene function of Att and Def2 was investigated by gene silencing. The gene knockdown effect on bacteria and parasite abundance was evaluated by qPCR, and parasite development was verified by light microscopy. We demonstrate that L. longipalpis larvae and adults trigger AMPs expression during feeding, which corresponds to an abundant presence of bacteria. Att and Def2 expression were significantly increased in Leishmania-infected females, while Att suppression favored bacteria growth. In conclusion, L. longipalpis AMPs’ expression is tuned in response to bacteria and parasites but does not seem to interfere with the Leishmania cycle.

Highlights

Antimicrobial peptides (AMPs) are typically cationic peptides with an overall positive charge and hydrophobic amino acid residues [1]
defensin 1 (Def1) and defensin 2 (Def2) were previously identified [31,33] and in the present work we described two other defensin sequences Defensin 3 (Def3) and defensin 4 (Def4) that contain the six conserved cysteine residues (Figure S3) characterizing these AMPs (InterPro IPR001542) [34]
We have previously identified and characterized an attacin (Att), a cecropin (Cec), andWe twohave defensin genes (Def1 and Def2)

Summary

Introduction

Antimicrobial peptides (AMPs) are typically cationic peptides with an overall positive charge and hydrophobic amino acid residues [1]. They can kill or neutralize Gram-negative and Gram-positive bacteria, fungi, and parasites [2,3]. One classical and well-known aspect of immunity is fat body AMPs synthesis and release into hemolymph. This response in Drosophila is coordinated by the Toll and IMD pathways, which are the major immunity regulatory pathways in this insect [6].

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