Injury and immune response: applying the danger theory to mosquitoes

Abstract

The insect immune response can be activated by the recognition of both non-self and molecular by-products of tissue damage. Since pathogens and tissue damage usually arise at the same time during infection, the specific mechanisms of the immune response to microorganisms, and to tissue damage have not been unraveled. Consequently, some aspects of damage caused by microorganisms in vector-borne arthropods have been neglected. We herein reassess the Anopheles–Plasmodium interaction, incorporating Matzinger’s danger/damage hypothesis and George Salt’s injury assumptions. The invasive forms of the parasite cross the peritrophic matrix and midgut epithelia to reach the basal lamina and differentiate into an oocyst. The sporozoites produced in the oocyst are released into the hemolymph, and from there enter the salivary gland. During parasite development, wounds to midgut tissue and the basement membrane are produced. We describe the response of the different compartments where the parasite interacts with the mosquito. In the midgut, the response includes the expression of antimicrobial peptides, production of reactive oxygen species, and possible activation of midgut regenerative cells. In the basal membrane, wound repair mainly involves the production of molecules and the recruitment of hemocytes. We discuss the susceptibility to damage in tissues, and how the place and degree of damage may influence the differential response and the expression of damage associated molecular patterns (DAMPs). Knowledge about damage caused by parasites may lead to a deeper understanding of the relevance of tissue damage and the immune response it generates, as well as the origins and progression of infection in this insect–parasite interaction.

Extracellular ATP activates MAPK and ROS signaling during injury response in the fungus Trichoderma atroviride

“…Interestingly, our data show that eATP induces conidiation in response to injury and suggest that eATP is an important signal molecule that is released from damaged hyphae. Thus, eATP can also be considered a damage signaling molecule in fungi, which plays a similar role in wound signaling to that reported in triggering immune responses in mammals ( Chen and Nuñez, 2010 ; Zeiser et al, 2011 ; Cordeiro and Jacinto, 2013 ), fish ( Kawate et al, 2009 ), insects ( Moreno-García et al, 2014 ), algae ( Torres et al, 2008 ), and plants ( Chivasa et al, 2009 ). Elevations in the concentration of intracellular calcium have also been observed in Arabidopsis upon application of eATP ( Tanaka et al, 2010 ).…”

Limited Specificity in the Injury and Infection Priming against Bacteria in Aedes aegypti Mosquitoes

“…However, it seems that in A. aegypti the concurrence of damage and the pathogen leaded to an optimal immune response. Several DAMPs have been found in insects ( Moreno-García et al, 2014b ). It will be very interesting to determine the DAMPs particularly involved in the A. aegypti ’s priming against bacteria.…”

Silencing of Anopheles stephensi Heme Peroxidase HPX15 Activates Diverse Immune Pathways to Regulate the Growth of Midgut Bacteria

“…Several studies revealed that wild type or laboratory-reared mosquito midgut is housed by a variety of bacteria (Minard et al, 2013; Kajla et al, 2015a) and their interaction with different development stages of Plasmodium also determines the mosquito cycle of the parasite (Touré et al, 2000; Dong et al, 2009; Cirimotich et al, 2011b; Wang et al, 2011; Boissière et al, 2012; Moreno-García et al, 2014). In addition, the type and number of bacteria also vary during different development stages and habitat of the mosquito (Wang et al, 2011; Minard et al, 2013; Kajla et al, 2015a).…”