Abstract
Directed differentiation of pluripotent stem cells into specialized cell types represents an invaluable tool for a wide range of applications. Here, we have exploited single-cell transcriptomic data to develop a stepwise in vitro differentiation system from mouse embryonic stem cells into adrenocortical cells. We show that during development, the adrenal primordium is embedded in an extracellular matrix containing tenascin and fibronectin. Culturing cells on fibronectin during differentiation increased the expression of the steroidogenic marker NR5A1. Furthermore, 3D cultures in the presence of protein kinase A (PKA)-pathway activators led to the formation of aggregates composed of different cell types expressing adrenal progenitor or steroidogenic markers, including the adrenocortical-specific enzyme CYP21A1. Importantly, in-vitro-differentiated cells responded to adrenocorticotropic hormone (ACTH) and angiotensin II with the production of glucocorticoids and mineralocorticoids, respectively, thus confirming the specificity of differentiation toward the adrenal lineage.