Identification of overlapping and distinct mural cell populations during early embryonic development

Abstract

AbstractMural cells are an essential perivascular cell population that associate with blood vessels and contribute to vascular stabilization and tone. In the embryonic zebrafish vasculature,pdgfrbandtaglnare commonly used as markers for identifying pericytes and vascular smooth muscle cells (vSMCs). However, the expression patterns of these markers used in tandem have not been fully described. Here, we used theTg(pdgfrb:Gal4FF; UAS:RFP)andTg(tagln:NLS-EGFP)transgenic lines to identify single- and double-positive perivascular populations in the cranial, axial, and intersegmental vessels between 1 and 5 days post-fertilization. From this comparative analysis, we discovered two novel regions oftagln-positive cell populations that have the potential to function as mural cell precursors. Specifically, we found that the hypochord— a reportedly transient structure—contributes totagln-positive cells along the dorsal aorta. We also identified a unique sclerotome-derived mural cell progenitor population that resides along the midline between the neural tube and notochord and contributes to intersegmental vessel mural cell coverage. Together, our findings highlight the variability and versatility of trackingpdgfrbandtaglnexpression in mural cells of the developing zebrafish embryo.Summary StatementDetailed analysis ofpdgfrb/taglnvascular expression patterns in embryonic zebrafish reveals novel regions oftagln-positive populations such as the hypochord and a mural cell progenitor population adjacent to the midline.