Meeting Abstract
Hydractinia symbiolongicarpus, a colonial hydrozoan cnidarian, is a proven and tractable model for studying regeneration and stem cell biology. Its adult tissues contain stem cells called interstitial cells (or i-cells) that are responsible for their ability to regenerate after injury and to continuously renew somatic cells during normal homeostasis. Depending on their cellular context, i-cells have the ability to differentiate into several types of epithelial, neural, or germ line cells. However, the molecular mechanisms that regulate these developmental decisions and the transcriptional changes experienced by i-cells as they commit to different fates are largely unknown. In this study, we characterized the transcriptional profiles of i-cells at different stages of neurogenesis in adult feeding polyps. We performed fluorescence-activated cell sorting (FACS) using transgenic animals expressing reporters for key markers of specific stages in the neurogenic pathway, followed by RNA-seq differential expression analysis. We report full transcriptomes for Piwi1-expressing i-cells, SoxB2-expressing neural progenitors, and two subtypes of differentiated RFamide-expressing neurons. Current work is focused on identifying new cell type-specific markers, as well as candidate genes and signaling pathways involved in cell fate determination. These data provide the first characterization of the transcriptional repertoire of Hydractinia i-cells and their progeny, identifying specific targets for future functional studies. Understanding the mechanisms underlying the choice of i-cell trajectory may ultimately allow us to harness these mechanisms to identify new targets for therapies in regenerative medicine.
