Aedes aegypti midgut chymotrypsin has no significant role in blood meal protein digestion or fecundity
Year: 2025
Type: preprint
Abstract: ABSTRACT The Aedes aegypti mosquito is a vector of the dengue, Zika, and chikungunya viruses. The mosquito’s reliance on blood facilitates the transmission of these viral pathogens to human hosts. Digestion of blood meal proteins depends on the biphasic expression of serine proteases, with trypsin-like activity contributing to most of the activity in the midgut. Other proteases found in the mosquito midgut, serine collagenase- and chymotrypsin-like, are thought to contribute to midgut protein digestion, but their contribution is largely understudied. Thus, elucidating the activity and specific roles of midgut proteases will help understand the complexity of the digestion process and help validate these proteolytic enzymes as potential inhibitor targets for the development of a new vector control strategy. Herein, we focused on characterizing the activity profile and role of Ae. aegypti chymotrypsin (AaCHYMO). Knockdown studies resulted in the elimination and significant reduction of chymotrypsin-like activity in blood fed midgut extracts, while in vitro fluorescent and blood protein digestion assays revealed important substrate specificity differences when compared to human and bovine chymotrypsin. Interestingly, the knockdown of AaCHYMO did not influence fecundity, indicating that blood protein digestion involves an intricate network of proteases working collectively to degrade blood proteins fully. Furthermore, knockdown of the ecdysone receptor (EcR) led to a decrease in overall AaCHYMO expression and chymotrypsin-like activity in the mosquito, which may play an important regulatory role. Altogether, the study of AaCHYMO is the first step in validating which mosquito midgut proteases are potential targets for the development of inhibitors.
Authors: Abigail G. Ramirez, Jun Isoe, Mateus Sá M Serafim, Daniel Fong, My Anh Le, James T. Nguyen, Olive E. Burata, Rachael M. Lucero, Alberto A. Rascón
Language: English
Field: Medicine
Domain: Health Sciences
Open Access status: green
OpenAlex ID: W4405988058