Infection-derived lipids elicit an immune deficiency circuit in arthropods

Abstract

The insect immune deficiency (IMD) pathway resembles the tumour necrosis factor receptor network in mammals and senses diaminopimelic-type peptidoglycans present in Gram-negative bacteria. Whether unidentified chemical moieties activate the IMD signalling cascade remains unknown. Here, we show that infection-derived lipids 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphoglycerol (POPG) and 1-palmitoyl-2-oleoyl diacylglycerol (PODAG) stimulate the IMD pathway of ticks. The tick IMD network protects against colonization by three distinct bacteria, that is the Lyme disease spirochete Borrelia burgdorferi and the rickettsial agents Anaplasma phagocytophilum and A. marginale. Cell signalling ensues in the absence of transmembrane peptidoglycan recognition proteins and the adaptor molecules Fas-associated protein with a death domain (FADD) and IMD. Conversely, biochemical interactions occur between x-linked inhibitor of apoptosis protein (XIAP), an E3 ubiquitin ligase, and the E2 conjugating enzyme Bendless. We propose the existence of two functionally distinct IMD networks, one in insects and another in ticks.

Tick-Pathogen Interactions and Vector Competence: Identification of Molecular Drivers for Tick-Borne Diseases

“…The answer to this question is that several of the processes involved in tick-pathogen interactions have also been identified in other vector-pathogen interactions (see for example, Beerntsen et al, 2000; Vlachou et al, 2005; Wang et al, 2010; Gómez-Díaz et al, 2012; Sabin et al, 2013; Ramphul et al, 2015; Eng et al, 2016; Shaw et al, 2017). For example, as described in ticks, receptor-ligand-like interactions mediate pathogen recognition and infection in mosquitoes (Beerntsen et al, 2000).…”

“…For example, Tudor-SN, a conserved component of the basic RNAi machinery with a variety of functions including immune response and gene regulation, is involved in defense against infection in Drosophila (Sabin et al, 2013) but not in ticks (Ayllón et al, 2015b). The IMD pathway is involved in protection against infection in arthropods, but recent results support the existence of two functionally distinct IMD circuits in insects and ticks (Shaw et al, 2017). Future comparative analyses between different vector species will provide additional information on the functional implication of the different biological processes in vector-pathogen interactions and vector competence (Gerold et al, 2017).…”

A Novel Combined Scientific and Artistic Approach for the Advanced Characterization of Interactomes: The Akirin/Subolesin Model

“…Therefore, AKR/SUB constitute a good model for the study of structural, functional, and evolutionary biology due to their conserved function in the regulation of different biological processes throughout the metazoan [16][17][18]. However, differences in results available on the AKR interactome and its functional implications pose a challenge for the understanding of the function of this protein [17][18][19][20][21][22][23][24][25][26][27][28]. For example, it is unknown how AKR/SUB-protein interactions regulate signaling pathways such as the NF-κB involved in the regulation of immune response.…”

Quantitative Proteomics Identifies Metabolic Pathways Affected by Babesia Infection and Blood Feeding in the Sialoproteome of the Vector Rhipicephalus bursa

“…While Babesia infection increased in SGs, the opposite occurred in larvae suggesting an impact in Babesia transovarial transmission since the parasite load decreased abruptly (−138.53%, p < 0.001) ( Figure 7B). The hypothesis of ub2n expression stabilization that could stimulate the IMD signalling pathway promoting antimicrobial peptides production [83] capable to control apicomplexan infection [69] is discarded in this context since the silencing efficiency was similar to the adult phase. Such decrease of infection could be explained by a putative effect of ub2n silencing in ovaries, i.e., could have blocked the invasion of B. ovis in the ovaries and consequently through the progeny.…”