Temporal dynamics of the ABC transporter response to insecticide treatment: insights from the malaria vector Anopheles stephensi

Abstract

In insects, ABC transporters have been shown to contribute to defence/resistance to insecticides by reducing toxic concentrations in cells/tissues. Despite the extensive studies about this detoxifying mechanism, the temporal patterns of ABC transporter activation have been poorly investigated. Using the malaria vector Anopheles stephensi as a study system, we investigated the expression profile of ABC genes belonging to different subfamilies in permethrin-treated larvae at different time points (30 min to 48 h). Our results showed that the expression of ABCB and ABCG subfamily genes was upregulated at 1 h after treatment, with the highest expression observed at 6 h. Therefore, future investigations on the temporal dynamics of ABC gene expression will allow a better implementation of insecticide treatment regimens, including the use of specific inhibitors of ABC efflux pumps.

The choreography of the chemical defensome response to insecticide stress: insights into the Anopheles stephensi transcriptome using RNA-Seq

“…Likewise, in larvae of a susceptible strain of the mosquito Anopheles stephensi exposed to permethrin, it was analysed the expression pattern of six ABC transporter genes at seven time-points from 30 minutes to 48 hours after exposure. All of these genes were found differentially expressed compared to the untreated larvae at each time-point and showed a modulated transcriptional response across time, with the maximum up-regulation after six hours of exposure22. Similar patterns were also found for genes encoding for Cuticular Proteins in the mosquito Culex pipiens pallens 23.…”

“…Third-instar larvae were exposed to 0.137 mg/L of permethrin22. Larval mortality after six, 24, and 48 hours of permethrin exposure was 33%, 45%, and 76% respectively.…”

“…These results are concordant with our previous studies on induction of ABC transporters in An. stephensi by permethrin2233 and, more in general, with the even more numerous evidences for ABC transporters involvement in arthropod defense against insecticides92233343536373839.…”

“…However, these are single snapshots of the defense response that do not allow us to know if and how the differentially expressed genes are modulated during toxicant exposure. On the other hand, some studies have investigated the expression profiles of subsets of genes at different time-points during individuals’ exposure to toxicants142223242526. For example, in the mosquito Culex quinquesfasciatus , multiple P450 genes were found co-upregulated in resistant strains during a time course of 12, 24, 48 and 72 hours of permethrin exposure2425.…”

Exposure to amitraz, fipronil and permethrin affects cell viability and ABC transporter gene expression in an Ixodes ricinus cell line

“…They have been implicated in the development of resistance to chemotherapeutics in cancer patients [13] and, more recently, in resistance of mosquitoes to insecticides [14, 15] and of different helminths to anthelmintic drugs [16, 17]. Studies carried out in Rhipicephalus microplus ticks have shown that overexpression of ABCT genes is associated with resistance to the drug ivermectin [18], and upregulation of several transporter genes follows exposure to ivermectin [19].…”