Arthropods Under Pressure: Stress Responses and Immunity at the Pathogen-Vector Interface

Abstract

Understanding what influences the ability of some arthropods to harbor and transmit pathogens may be key for controlling the spread of vector-borne diseases. Arthropod immunity has a central role in dictating vector competence for pathogen acquisition and transmission. Microbial infection elicits immune responses and imparts stress on the host by causing physical damage and nutrient deprivation, which triggers evolutionarily conserved stress response pathways aimed at restoring cellular homeostasis. Recent studies increasingly recognize that eukaryotic stress responses and innate immunity are closely intertwined. Herein, we describe two well-characterized and evolutionarily conserved mechanisms, the Unfolded Protein Response (UPR) and the Integrated Stress Response (ISR), and examine evidence that these stress responses impact immune signaling. We then describe how multiple pathogens, including vector-borne microbes, interface with stress responses in mammals. Owing to the well-conserved nature of the UPR and ISR, we speculate that similar mechanisms may be occurring in arthropod vectors and ultimately impacting vector competence. We conclude this Perspective by positing that novel insights into vector competence will emerge when considering that stress-signaling pathways may be influencing the arthropod immune network.

Unpacking the intricacies of Rickettsia–vector interactions

“…Specifically, in the arthropod midgut, rickettsiae are exposed to a milieu of molecules, ranging from antimicrobial peptides (AMPs) and reactive oxygen species (ROS) to nutrients. While blood provides the arthropod with protein-rich metabolites necessary for development and egg production, the process of breaking down hemoglobin releases dangerous AMPs and toxic heme into the midgut lumen where newly acquired rickettsiae can be targeted [36]. For arthropods, the release of toxins during blood meal digestion can be quite dangerous.…”

Ticks: More Than Just a Pathogen Delivery Service

“…Some immune pathways are described as restricting vector-borne microbes, such as the Immune Deficiency pathway ( Rosa et al, 2016 ; Capelli-Peixoto et al, 2017 ; Shaw et al, 2017 ; Carroll et al, 2019 ), the JAK-STAT pathway ( Liu et al, 2012 ; Smith et al, 2016 ), the RNAi pathway ( Rückert et al, 2014 ; Schnettler et al, 2014 ; Grubaugh et al, 2016 ; Hart and Thangamani, 2021 ), and phagocytic hemocytes ( Coleman et al, 1997 ; Dunham-Ems et al, 2009 ; Talactac et al, 2021 ); however, vectored pathogens are still able to colonize the tick. Whether this is through microbial-mediated immune evasion/suppression or through immunological tolerance from the arthropod is not clearly defined ( Sonenshine and Macaluso, 2017 ; Shaw et al, 2018 ; Boulanger and Wikel, 2021 ; Rosche et al, 2021 ). Prolonged nutrient limitation between bloodmeals and competition with the resident microbiota/endogenous virome are also restrictive forces that must be dealt with ( Bell-Sakyi and Attoui, 2013 ; Shaw et al, 2018 ; O’Neal et al, 2020 ; Samaddar et al, 2020 ; Bonnet and Pollet, 2021 ; Narasimhan et al, 2021 ).…”

An Insight Into The MicroRNA Profiles of An Ectoparasite Mite Varroa Destructor (Acari: Varroidae), The Primary Vector of Deformed Wing Virus (DWV) of The Honey Bee

“…Not surprisingly, this data suggests the signi cance of these biological processes. Proteins involved in endocytosis and protein processing in ER could provide signi cant clues towards viral infection (Wang et al, 2013;Rosche et al, 2021) process in Varroa.…”