Development of a High-Content Stem Cell Focused Drug Screening Platform for Schistosoma mansoni Using Developmentally...

Globally, more than a quarter of a billion people are infected with Schistosoma blood parasites that cause the debilitating disease human schistosomiasis. To assist drug discovery, we developed a novel high content drug screening platform that exploits the extraordinary stem cell biology of the developing parasite.

Employing non-synchronous in vitro-grown liver stage schistosomula, fluorescence-based staining, confocal laser scanning microscopy, and segmentation of multi-parasite images, the platform was designed to enable high-content quantitative analysis of dividing somatic neoblasts within the parasite to define phenotype.

To establish, refine, and test the approach we analysed stem cell proliferation in liver stage schistosomula and validated the impact of EC-144, a compound that supresses Schistosoma neoblast proliferation. Primary drug screening was then done using a stem cell focused library containing 280 compounds, 45 of which attenuated stem cell proliferation by at least 75%. Sixteen 'hit' compounds were prioritised for further testing/confirmation, with testing done in both simple and complex media. Six compounds were finally selected for further investigation, all of which killed or constrained the development of schistosomula and abolished both somatic and germinal stem cell proliferation in adult male and female worms.

In addition to identifying a panel of new anti-schistosomal compounds with associated predicted targets, the findings provide mechanistic insights into the somatic stem cell biology of schistosomes. Further application of this platform, which offers a new approach to assessing compound susceptibility on schistosomula, should accelerate lead compound discovery to help fight human schistosomiasis.