D3327: MicroRNA profiling in body lice: Insights into parasite-host interactions

Host-parasite co-evolution has shaped unique biological interactions, including the potential cross-species regulation of physiology through molecules such as microRNAs (miRNAs). The body louse, an obligate blood-feeding ectoparasite who can transmit bacterial pathogens, provides a valuable model for investigating host-parasite interactions. Due to its exclusive dependence on human blood, body lice may continuously ingest human-derived miRNAs and inject their own miRNAs through saliva into host, facilitating a bidirectional exchange of regulatory molecules. For miRNA extraction from specific tissues, 3 to 5-day-old adult body lice were dissected to collect salivary glands and the alimentary tracts following blood feeding. Human blood-derived miRNAs were extracted using the PAXgene Blood miRNA Kit, while miRNAs from louse tissues were isolated using the PureLink miRNA Isolation Kit. These miRNAs were sequenced to idistinguish between human- and lous-derived miRNAs using miRDeep2 algorithm. Sequencing of miRNAs from mixed-stage body lice identified 105 miRNAs, including 50 novel ones. Moreover, miRNAs originating from human blood were detected within the body lice, with 118 miRNAs matching exactly to the human genome, suggesting their human-origin. We identified both body louse-specific miRNAs and human-derived miRNAs transferred to lice during blood feeding by analyzing the salyvary gland/saliva of body lice and alimentary tract/hemolymph of post-blood meal body lice with human blood. By miRNA sequencing, 26 salivary gland-specific miRNAs potentially transferable from lice to humans, were identified. Ongoing research aims to quantify temporal changes in miRNA levels over time post-feeding and confirm the presence of louse-derived miRNAs transferred into human hosts.