Miniature spatial transcriptomics for studying parasite-endosymbiont relationships at the micro scale

Filarial worms are parasitic nematodes that are causative agents of a number of important human diseases, including lymphatic filariasis (Wuchereria bancrofti, Brugia malayi, and B. timori) and river blindness (Onchocerca volvulus). These worms have evolved a mutualistic association with Wolbachia, an endosymbiotic bacteria essential for their development, reproduction, and survival. The mechanisms that underlie the dependency of the filarial worms on the fitness of these bacteria have yet to be elucidated. We set out to perform a spatial characterization across the reproductive tissues of female B. malayi worms using Spatial Transcriptomics (ST). We provide a proof-of-concept for "miniatureST" to explore spatial gene expression patterns in small sample types, demonstrating the method's ability to uncover nuanced tissue region expression patterns, observe the spatial localization of key B. malayi - Wolbachia pathway genes, and co-localize B. malayi spatial transcriptomics in Wolbachia tissue regions. We envision the approach can be applied to other small organisms, such as the plethora of other disease-causing parasitic worms.