Serpins in Tick Physiology and Tick-Host Interaction

Abstract

Tick saliva has been extensively studied in the context of tick-host interactions because it is involved in host homeostasis modulation and microbial pathogen transmission to the host. Accumulated knowledge about the tick saliva composition at the molecular level has revealed that serine protease inhibitors play a key role in the tick-host interaction. Serpins are one highly expressed group of protease inhibitors in tick salivary glands, their expression can be induced during tick blood-feeding, and they have many biological functions at the tick-host interface. Indeed, tick serpins have an important role in inhibiting host hemostatic processes and in the modulation of the innate and adaptive immune responses of their vertebrate hosts. Tick serpins have also been studied as potential candidates for therapeutic use and vaccine development. In this review, we critically summarize the current state of knowledge about the biological role of tick serpins in shaping tick-host interactions with emphasis on the mechanisms by which they modulate host immunity. Their potential use in drug and vaccine development is also discussed.

Genome sequences of fourIxodesspecies expands understanding of tick evolution

“…Annotating the lncRNAs was difficult due to the paucity of information on lncRNAs in the species studied here and the lack of previous complete annotation of lncRNAs in I. ricinus . To accurately annotate the lncRNAs, we used a published lncRNA dataset that included both putative and consensus lncRNAs for I. ricinus (Medina, Abbas, et al 2022). Consensus lncRNAs from this dataset were considered as high-confidence annotations.…”

“…Serpins are protease inhibitors involved in the regulation of many physiological processes in vertebrates and invertebrates (Huntington 2011), and even viruses (Spence et al 2021). In ticks, serpins are salivary components responsible for anti-hemostatic, anti-inflammatory and immunomodulatory effects in the vertebrate host (Abbas et al 2022). Serpins from I. ricinus can be divided into two groups, Iripins ( I. ricinus serpins) and IRIS-like serpins, which refers to the first described tick serpin IRIS (Leboulle et al 2002).…”

MicroRNAs reshape the immunity of insects in response to bacterial infection

“…In insects, these pathways initiate the production of a wide range of antimicrobial peptides when fungal and bacterial infections occur, which are implicated as a mechanism of antiviral immunity (5)(6)(7)(8). The Toll pathway controls the expression of the antifungal peptide, whereas the IMD pathway modulates the expression of the peptide that defends against Gram-negative bacteria (9)(10)(11)(12). The expression of the genes that encode these peptides can, therefore, be used as a measure of the levels at which Toll and IMD signaling is activated.…”

Iripin-1, a new anti-inflammatory tick serpin, inhibits leukocyte recruitment in vivo while altering the levels of chemokines and adhesion molecules

“…For this reason, ticks secrete saliva, containing anti-inflammatory and immunomodulatory molecules, into the wound ( 20 , 21 ). Based on their presence in tick saliva and the ability to modulate immune reaction, serpins are one of the protein families that ticks utilize to attenuate the host’s inflammatory response ( 22 ). To date, tick serpins have been shown to reduce vascular permeability ( 23 – 25 ), suppress the production of pro-inflammatory cytokines and chemokines ( 26 – 30 ), and attenuate nitric oxide production by macrophages ( 31 ).…”