MicroRNAs from saliva of anopheline mosquitoes mimic human endogenous miRNAs and may contribute to...

Area of Science:

• * Molecular biology and entomology.
• * Vector-borne disease research.

Background:

• * Haematophagous arthropods, like mosquitoes, inject saliva containing proteins to manage host responses during blood feeding.
• * Animal body fluids, including saliva, contain microRNAs (miRNAs), small non-coding RNAs involved in gene regulation.

Purpose of the Study:

• * To characterize the miRNA repertoire in the saliva and salivary glands of the African malaria vector, Anopheles coluzzii.
• * To investigate the potential role of these miRNAs in host manipulation during blood feeding.

Main Methods:

• * Small RNA sequencing (small RNA-Seq) was employed to identify and quantify miRNAs.
• * Bioinformatic analyses were used to assess miRNA distribution, conservation, and potential targets.

Main Results:

• * Identified 214 miRNAs in An. coluzzii, including novel and sex-biased miRNAs, with asymmetric distribution between saliva and salivary glands.
• * A subset of saliva miRNAs showed evolutionary conservation across mosquito and tick species.
• * Eleven abundant An. coluzzii saliva miRNAs mimicked human miRNAs and were predicted to target host mRNAs involved in immune and inflammatory responses.

Conclusions:

• * An. coluzzii saliva contains a distinct repertoire of miRNAs, suggesting active selection for salivary miRNAs.
• * Salivary miRNAs may play a role in modulating host immune and inflammatory responses.
• * This study proposes a novel mechanism of vector-host interaction where miRNAs in saliva contribute to host manipulation, potentially impacting pathogen transmission.