Characterization of the Rel2-regulated transcriptome and proteome of Anopheles stephensi identifies new anti-Plasmodium factors

Abstract

Mosquitoes possess an innate immune system that is capable of limiting infection by a variety of pathogens, including the Plasmodium spp. parasites responsible for human malaria. The Anopheles immune deficiency (IMD) innate immune signaling pathway confers resistance to Plasmodium falciparum. While some previously identified Anopheles anti-Plasmodium effectors are regulated through signaling by Rel2, the transcription factor of the IMD pathway, many components of this defense system remain uncharacterized. To begin to better understand the regulation of immune effector proteins by the IMD pathway, we used oligonucleotide microarrays and iTRAQ to analyze differences in mRNA and protein expression, respectively, between transgenic An. stephensi mosquitoes exhibiting blood meal-inducible overexpression of an active recombinant Rel2 and their wild-type conspecifics. Numerous genes were differentially regulated at both the mRNA and protein levels following induction of Rel2. While multiple immune genes were up-regulated, a majority of the differentially expressed genes have no known immune function in mosquitoes. Selected up-regulated genes from multiple functional categories were tested for both anti-Plasmodium and anti-bacterial action using RNA interference (RNAi). Based on our experimental findings, we conclude that increased expression of the IMD immune pathway-controlled transcription factor Rel2 affects the expression of numerous genes with diverse functions, suggesting a broader physiological impact of immune activation and possible functional versatility of Rel2. Our study has also identified multiple novel genes implicated in anti-Plasmodium defense.

Plasmodium berghei induced priming in Anopheles albimanus independently of bacterial co-infection

“…Also for the first time in invertebrates, we documented that the humoral immune response to the priming and challenge infections followed a biphasic rather than sustained pattern, indicating an underlying mechanism akin to immune memory. After induction of the host defense, a broad spectrum of effector responses could explain the previously observed overlap between the anti-bacterial and anti-plasmodial mosquito immune responses (Pike et al, 2014).…”

“…For mosquitoes it has been reported that pattern recognition receptors (PRRs) participate in the activation of the innate immune system through the recognition of the pathogen molecular patterns (PAMPs) of invading microorganisms (Dimopoulos et al, 2002;Dimopoulos et al, 1997;Dimopoulos et al, 1998). At least three signaling pathways that mediate the immune response are conserved in mosquitoes and other insects-that of Toll-like receptors, of Immune Deficiency (IMD), and of the Janus kinase signal transducer and activator of transcription (JAK-STAT) (De Gregorio et al, 2002;Meister et al, 2005;Pike et al, 2014;Sanders et al, 2005). Toll components are active against Gram-positive bacteria, fungi (De Gregorio et al, 2002) and viral infections (Costa et al, 2009;Garver et al, 2009).…”

Role of NF-kβ factor Rel2 during Plasmodium falciparum and bacterial infection in Anopheles dirus

“…Evidence from previous studies and this one portrays the significance of Rel2 against P. falciparum and bacterial infection. Nonetheless, Rel2 has the tendency to affect non-immune genes and the upregulation of the transcription factor may inadvertently have an impact on mosquito fitness and fecundity [ 39 ]. Further research has to be conducted to fully comprehend the ramifications of altering the natural gene expression of the mosquito.…”

Gene Drive for Mosquito Control: Where Did It Come from and Where Are We Headed?

“…gambiae and Ae. aegypti as potential candidates for such efforts [ 113 , 114 , 115 , 116 , 117 , 118 , 119 , 120 , 121 , 122 , 123 , 124 , 125 , 126 ]. For example, perturbations of AKT signaling and transgene-mediated expression of the IMD signaling gene Rel2 have both been demonstrated to increase the ability of An.…”