Identification and Expression Characterization of Leucine-Rich Repeat Proteins in Aedes albopictus in Response to Dengue Virus Infection

Mosquitoes transmit a wide range of human pathogens, including Plasmodium parasites and arboviruses. Insects rely primarily on pattern recognition receptors (PRRs) to initiate innate immunity against invading pathogens. Leucine-rich repeat proteins (LRRPs), such as LRIM1 and APL1, are critical PRRs that mediate anti- Plasmodium immunity in Anopheles mosquitoes. However, the roles of these proteins in Aedes albopictus, a major vector of dengue virus (DENV), remain poorly understood. In this study, we identified 49 LRRP-coding genes in the Ae. albopictus genome. On the basis of LRR copy number and sequence features, these LRRPs were classified into five subfamilies: “Long” LRRPs, “Short” LRRPs, “TM” LRRPs, “Coil-less” LRRPs and “F-box” LRRPs. Phylogenetic and functional domain analysis revealed that the LRRPs of Ae. albopictus were highly conserved relative to their orthologs in other mosquito species. Expression profiling indicated that the LRIM1 and APL1A/B/C orthologs in Ae. albopictus display distinct expression patterns across developmental stages and in adult tissues. Furthermore, both blood feeding and DENV infection significantly modulated the transcriptional profiles of Ae. albopictus LRRPs. Collectively, our study provides a foundation for systematically exploring the functions of LRRPs during mosquito development, blood feeding, and innate immunity.