2-Cys peroxiredoxin is required in successful blood-feeding, reproduction, and antioxidant response in the hard tick Haemaphysalis longicornis

Abstract

BackgroundTicks are obligate hematophagous arthropods that feed on vertebrate blood that contains iron. Ticks also concentrate host blood with iron; this concentration of the blood leads to high levels of iron in ticks. The host-derived iron reacts with oxygen in the tick body and this may generate high levels of reactive oxygen species, including hydrogen peroxide (H2O2). High levels of H2O2 cause oxidative stress in organisms and therefore, antioxidant responses are necessary to regulate H2O2. Here, we focused on peroxiredoxin (Prx), an H2O2-scavenging enzyme in the hard tick Haemaphysalis longicornis.MethodsThe mRNA and protein expression profiles of 2-Cys peroxiredoxin (HlPrx2) in H. longicornis were investigated in whole ticks and internal organs, and developmental stages, using real-time PCR and Western blot analysis during blood-feeding. The localization of HlPrx2 proteins in tick tissues was also observed by immunostaining. Moreover, knockdown experiments of HlPrx2 were performed using RNA interference to evaluate its function in ticks.ResultsReal-time PCR showed that HlPrx2 gene expression in whole ticks and internal organs was significantly upregulated by blood-feeding. However, protein expression, except in the midgut, was constant throughout blood-feeding. Knockdown of the HlPrx2 gene caused significant differences in the engorged body weight, egg weight and hatching rate for larvae as compared to the control group. Finally, detection of H2O2 after knockdown of HlPrxs in ticks showed that the concentration of H2O2 significantly increased before and after blood-feeding.ConclusionTherefore, HlPrx2 can be considered important for successful blood-feeding and reproduction through the regulation of H2O2 concentrations in ticks before and after blood-feeding. This study contributes to the search for a candidate target for tick control and further understanding of the tick’s oxidative stress coping mechanism during blood-feeding.Electronic supplementary materialThe online version of this article (doi:10.1186/s13071-016-1748-2) contains supplementary material, which is available to authorized users.

A Peroxiredoxin From the Haemaphysalis longicornis Tick Affects Langat Virus Replication in a Hamster Cell Line

“…HlPrx was classified as Prx VI, and the identity with BHK cell-derived Prx VI, a 1-Cys Prx, was 62.8%, with 97% coverage against the Prx VI of BHK cells (Supplementary Table 2). HlPrx2 could be classified as Prx II, since the localization within tick hemocytes, a cell in tick hemolymph, is the cytosol (Kusakisako et al, 2016b) and the full length of the amino acid sequence is almost the same between HlPrx2 and Prx II (Supplementary Table 2). The identity with BHK cell-derived Prx II was 75.3%, with 96% coverage against the Prx II of BHK cells ( Supplementary Table 1).…”

“…The survival rate of the BHK-HlPrx2 cell line was higher than that of the other cell lines (Figure 2C). The HlPrx2 protein was reported to play an important role in the antioxidant activity in tick blood feeding and oviposition by controlling the H 2 O 2 concentration in ticks (Kusakisako et al, 2016b). In addition, tick Prxs would transfer to their host body during tick blood feeding (Tsuji et al, 2001;Narasimhan et al, 2007;Tirloni et al, 2015;Kim et al, 2016).…”

Molecular characterization of a typical 2‐Cys thioredoxin peroxidase from the Asiatic rice borer Chilo suppressalis and its role in oxidative stress

“…These enzymes play a pivotal role in protecting against cellular oxidative damage induced by temperature variation, toxic heavy metals, insecticides, UV radiation, and microbial invasion (Wan et al., ; Yu et al., ; Zhang & Lu, ; Zhang et al., ). TPXs are required for successful ingestion and reproduction because they regulate the H 2 O 2 concentration in blood‐feeding insect species such as mosquitoes and ticks (Kusakisako et al., ; Peterson & Luckhart, ). Furthermore, overexpression of Tpx can extend the lifespan of D. melanogaster (Radyuk et al., ).…”

“…Furthermore, knockdown of Tpx genes in the common cutworm, Spodoptera litura , the cotton bollworm, Helicoverpa armigera , and the pea aphid, Acyrthosiphon pisum , by RNA interference (RNAi) accelerates insect death following fungal and viral invasion (Chen et al., ; Zhang & Lu, ; Zhang et al., ). Moreover, silencing a Tpx gene in the tick species, Haemaphysalis longicornis , leads to a significant decrease in body weight, egg weight, and hatching rate (Kusakisako et al., ). Together, these results strongly support the view that TPXs are of vital importance for insect survival.…”

Transcriptional activities of two newly identified Haemaphysalis longicornis tick‐derived promoter regions in the Ixodes scapularis tick cell line (ISE6)

“…Therefore, alternative approaches to controlling tick infestations are necessary. The hard tick Haemaphysalis longicornis is one of the most studied ticks in the world (Galay et al ., ; Kusakisako et al ., ; Maeda et al ., ; Talactac et al ., ). The H. longicornis tick, mainly distributed in East Asia and Australia, is a known vector of babesiosis and theileriosis (Jongejan & Uilenberg, ).…”