Reconstitution of human adrenocortical specification and steroidogenesis using induced pluripotent stem cells [bulk RNA-seq]

The adrenal cortex produces vital steroid hormones that maintain homeostasis. While steroid hormones produced from the fetal zone adrenal cortex are essential for both fetal development and maintenance of pregnancy, the molecular mechanisms leading to human adrenal cortex development and steroid synthesis remain poorly understood due to the paucity of model systems. Through progressive generation of fetal zone adrenal cortex-like cells (FZLCs) from human induced pluripotent stem cells through posterior intermediate mesoderm-like, adrenogenic coelomic epithelium and adrenal primordium-like states, we provide the first in vitro reconstitution of human adrenocortical fetal specification. Generation of FZLCs faithfully recapitulates human embryonic adrenal cortex specification as evidenced by histomorphological and ultrastructural analysis, transcriptional profiles and delta-5 steroid biosynthesis and occurs in an adrenocorticotropic hormone (ACTH)-independent manner, consistent with clinical observations. Furthermore, we demonstrate that FZLC generation is promoted by SHH and inhibited by NOTCH, ACTIVIN and WNT signaling and that steroid synthesis is amplified by ACTH/PKA signaling and blocked by pharmacologic inhibitors of delta 5 steroid synthesis enzymes. Finally, NR5A1 appear to self-stabilize its promoter activity and promote FZLC survival and steroidogenesis. Together, these findings provide a framework for understanding and reconstituting human adrenocortical development in vitro and pave the way for future cell-based therapies of adrenal insufficiency. Overall design: The following samples were prepared: fl0 hiPSC (WGNT SV20-211 [male, n =2]), aggregates at fl9 (whole WG+ fraction, WGNT SV20-211 [n=2]), fl14 (NT+ fraction, WGNT SV20-211 [n=2]), fl22 (NT+ fraction, WGNT SV20-211 [n=2]), fl22 (NT+ fraction, NT 312-2121 [female, n=2]), fl22 (NT+ fraction, WGNT SV20-KIKO19 [male, n=2]), ali21 (NT+ fraction, WGNT SV20-211 [n=1]), ali21 (NT+ fraction, NT 1390G-2125 [n=1]) and ali 28 (NT+ fraction, WGNT SV20-211 [n=1]), two human fetal stage (9 wpf) adrenal sample, one human fetal stage (9 wpf) heart sample.