Abstract
Eggs of blood fluke Schistosoma mansoni are the main causative agent of clinical manifestations of a disease called schistosomiasis. In the definitive host, eggs are laid in the mesenteric veins and then migrate through the intestinal wall to the gut and outer environment.
A large proportion of eggs, however, become entrapped in host tissues, typically the liver, causing inflammation and tissue damage. During this process, eggs secrete molecules to modulate host immune response.
We hypothesize that proteases and protease inhibitors play an important role during the infection. Our focus in this project is to identify them and measure their transcriptional levels in undeveloped and developed eggs.
Additionally, we included a comparison with eggs of another trematode Fasciola hepatica. These eggs pass from host bile ducts to the gut lumen and outer environment without any known pathological consequences for the host and without penetrating the tissues.
Therefore, we employ this organism as a useful comparative subject to decipher which proteases and inhibitors are common and which are unique for each of them. We isolated RNA from several developmental stages of eggs of both organisms, prepared cDNA libraries, performed Illumina sequencing and analyzed transcripts using a pipeline of bioinformatics tools.
By synthesis of database identifications and manual curation, we obtained a dataset of expressed proteases and protease inhibitors. Next, we identified orthologous proteins for both species and compared expression levels between them.