Functional Lactotrophs in Induced Adenohypophysis Differentiated From Human iPS Cells

Abstract

Prolactin (PRL), a hormone involved in lactation, is mainly produced and secreted by the lactotrophs of the anterior pituitary (AP) gland. We previously reported a method to generate functional adrenocorticotropic hormone-producing cells by differentiating the AP and hypothalamus simultaneously from human induced pluripotent stem cells (iPSCs). However, PRL-producing cells in the induced AP have not been investigated. Here, we confirmed the presence of PRL-producing cells and evaluated their endocrine functions. We differentiated pituitary cells from human iPSCs using serum-free floating culture of embryoid-like aggregates with quick reaggregation (SFEB-q) method and evaluated the appearance and function of PRL-producing cells. Secretion of PRL from the differentiated aggregates was confirmed, which increased with further culture. Fluorescence immunostaining and immunoelectron microscopy revealed PRL-producing cells and PRL-positive secretory granules, respectively. PRL secretion was promoted by various prolactin secretagogues such as thyrotropin-releasing hormone, vasoactive intestinal peptide, and prolactin-releasing peptide, and inhibited by bromocriptine. Moreover, the presence of tyrosine hydroxylase-positive dopaminergic nerves in the hypothalamic tissue area around the center of the aggregates connecting to PRL-producing cells indicated the possibility of recapitulating PRL regulatory mechanisms through the hypothalamus. In conclusion, we generated pituitary lactotrophs from human iPSCs; these displayed similar secretory responsiveness as human pituitary cells in vivo. In the future, this is expected to be used as a model of human PRL-producing cells for various studies, such as drug discovery, prediction of side effects, and elucidation of tumorigenic mechanisms using disease-specific iPSCs. Furthermore, it may help to develop regenerative medicine for the pituitary gland.

Recipe for pituitary organoids

“…Our pituitary organoids secrete anterior pituitary hormones such as GH ( 7 ) and PRL ( 15 ). Since supply of multiple anterior pituitary hormones is impaired in panhypopituitarism, the induction efficiency of multiple lineages should be improved.Pituitary organoids derived from hPSCs demonstratedly can function as a transplanted organ when ectopically transplanted into immunodeficient mice.…”

A New Experimental Tool Toward Understanding the Regulation of Human Prolactin Secretion and Functions

“…In conclusion, the novel technique reported by Miyake and colleagues ( 8 ) allowing the differentiation of lactotrophs from hiPSCs may provide a much-needed model to improve our understanding of the complex hypothalamic regulation of PRL secretion, particularly in humans. While these findings generate more questions than they answer, they open the possibility of new and exciting studies investigating the complexity and diversity of PRL regulation and function in humans.…”

“…A recent study developed a well-defined approach to differentiate human induced pluripotent stem cells (hiPSCs) into lactotrophs. In this report, published in Endocrinology , Miyake et al ( 8 ) differentiated pituitary cells from hiPCSs using a serum/free-floating culture of embryoid-like aggregates with a quick reaggregation method. They showed the presence of PRL-producing cells containing secretory granules by fluorescence immunostaining and immunoelectron microscopy; evaluated the secretion of PRL induced by relatively high concentrations of various known PRL secretagogues (the PRL-releasing peptide PrRP31, vasoactive intestinal peptide, and thyrotropin-releasing hormone) as well as the inhibition of PRL release by the DA agonist, bromocriptine.…”