Anopheline antiplatelet protein from mosquito saliva regulates blood feeding behavior

Abstract

The saliva of hematophagous arthropods is enriched with a complex mixture of antihemostatic molecules, the biological functions of which are largely unknown. Anopheline antiplatelet protein (AAPP) from malaria vector mosquito exhibits strong antiplatelet activity when bound directly to host collagen by its C-terminus and through its N-terminus with Ca 2+ -binding activity. To investigate the biological functions of AAPP in blood feeding behavior and malaria transmission, we generated transgenic Anopheles stephensi mosquito lines expressing anti-AAPP antibody single-chain fragment (scFv) in their salivary glands. The AAPP-specific collagen-binding activity was completely abolished by AAPP-scFv complex formation in the saliva. Probing and prediuresis time, feeding success, blood meal size, and fecundity, which are all fitness characteristics, were significantly reduced in the transgenic mosquitoes. However, oocysts number in these mosquitoes were not significantly reduced following blood meal intake from Plasmodium berghei -infected mice. These results show that although AAPP plays an important role in mosquito blood feeding, its neutralizing activity did not affect sporogonic development in our laboratory model, but its high fitness cost would pose a survival risk for parasite-infected mosquitoes in nature.

Influence of GST- and P450-based metabolic resistance to pyrethroids on blood feeding in the major African malaria vector Anopheles funestus

“…Salivary components permit mosquitoes to reduce their engorgement time and increase their likelihood of survival [ 5 ]. In the present study, we assessed the level of expression of genes encoding for some salivary proteins known to be involved on blood intake process of mosquitoes such as AAPP and members of D7 family proteins [ 6 , 47 , 48 ]. The comparative analysis of the expression level of these genes between CYP6P9a genotypes showed no significant difference between mosquitoes bearing the resistant allele and those with the susceptible one.…”

“…The blood feeding success of mosquitoes is facilitated by the biochemical proprieties of salivary gland proteins [5]. Indeed, some salivary proteins such as anopheline antiplatelet protein (AAPP), apyrase, gambiae Salivary Gland protein 6 (gSG6) and members of D7 family have been identified as vasodilators, anti-coagulants and inhibitors of platelet aggregation allowing mosquitoes to overcome host haemostatic mechanisms and to have a successful blood meal [5][6][7][8]. Mosquito fecundity was shown to vary by source and size of the blood meal with a difference of these two parameters resulting in significant variations of the number of eggs laid by each female mosquito [4,8].…”

Influence of GST- and P450-based metabolic resistance to pyrethroids on blood feeding in the major African malaria vectorAnopheles funestus

“…Salivary components permit mosquitoes to reduce their engorgement time and increase their likelihood of survival [5]. In the present study, we assessed the level of expression of genes encoding for some salivary proteins known to be involved on blood intake process of mosquitoes such as, AAPP and members of D7 family proteins [6,42,43]. The comparative analysis of the expression level of these genes between CYP6P9a genotypes showed no significant difference between mosquitoes bearing the resistant allele and those with the susceptible one.…”

Mosquito saliva as a potential source for COVID-19 Preventive Medicine – A brief review

“…Studies show that blood-sucking insects utilize a diverse array of feeding strategies on their hosts, enabling them to counteract the obstacles associated with host homeostasis [63]. The salivary proteins of arthropods, such as the anopheline antiplatelet protein (AAPP) in the saliva of An.…”