Project description:To determine whether the influences of Ixodes scapularis protein disulfide isomerase A6 (IsPDIA6) on Borrelia burgdorferi colonization is the result of physiological responses, we performed RNA-sequencing (RNA-seq) to compare the transcriptomes of control (GFP) and IsPDIA6-silenced ticks.
Project description:Adiponectin-mediated pathways contribute to mammalian homeostasis; however, little is known about adiponectin and adiponectin receptor signaling in arthropods. In this study, we demonstrate that Ixodes scapularis ticks have an adiponectin receptor-like protein (ISARL) but lack adiponectin, suggesting activation by alternative pathways. ISARL expression is significantly upregulated in the tick gut after Borrelia burgdorferi infection, suggesting that ISARL signaling may be co-opted by the Lyme disease agent. Consistent with this, RNA interference (RNAi)-mediated silencing of ISARL significantly reduced the B. burgdorferi burden in the tick. RNA-seq-based transcriptomics and RNAi assays demonstrate that ISARL-mediated phospholipid metabolism by phosphatidylserine synthase I is associated with B. burgdorferi survival. Furthermore, the tick complement C1q-like protein 3 interacts with ISARL, and B. burgdorferi facilitates this process. This study identifies a new tick metabolic pathway that is connected to the life cycle of the Lyme disease spirochete.
Project description:Ixodes scapularis are an important vector for at least six tick-borne human pathogens, including the predominant North American Lyme disease spirochete Borrelia burgdorferi. The ability for these ticks to survive in nature is credited, in part, to their ability to feed on a variety of hosts without excessive activation of the vertebrate immune system. While the ability for nymphal ticks to feed on a variety of hosts has been well-documented, the host-parasite interactions between larval I. scapularis and different vertebrate hosts is relatively unexplored. Here we report on the changes in the vertebrate transcriptome present at the larval tick bite site using the natural I. scapularis host Peromyscus leucopus, a non-natural rodent host Mus musculus (BALB/c), and humans. We note substantially less evidence of inflammation in P. leucopus compared to BALB/c mice and pronounced evidence of inflammation in humans. These data suggest that larval I. scapularis may have a reduced ability to suppress host immunity in non-natural hosts and expand our overall understanding of I. scapularis feeding.
