The pituitary gland, regulating various hormones, is central in the endocrine system. As spontaneous recovery from hypopituitarism is rare, and exogenous-hormone substitution is clumsy, pituitary replacement via regenerative medicine, using pluripotent stem cells, is desirable. We have developed a differentiation method that in mice yields pituitary organoids (POs) derived from human embryonic stem cells (hESC). Efficacy of these POs, transplanted subcutaneously into hypopituitary mice, in reversing hypopituitarism was studied.hESC-derived POs were transplanted into inguinal subcutaneous white adipose tissue (ISWAT) and beneath dorsal skin, a relatively avascular region (AR), of hypophysectomized severe combined immunodeficient (SCID) mice. Pituitary function was evaluated thereafter for ¾ 6mo, assaying basal plasma ACTH and ACTH response to corticotropin-releasing hormone (CRH) stimulation. Histopathologic examination of organoids 150d after transplantation assessed engraftment. Some mice received an inhibitor of vascular endothelial growth factor (VEGF) to permit assessment of how angiogenesis contributed to subcutaneous engraftment.During follow-up, both basal and CRH-stimulated plasma ACTH levels were significantly higher in the ISWAT group (p < 0.001 - 0.05 and 0.001 - 0.005, respectively) than in a sham-operated group. ACTH secretion also was higher in the ISWAT group than in the AR group. Histopathologic study found ACTH-producing human pituitary-cell clusters in both groups of allografts, which had acquired a microvasculature. POs qPCR showed expression of angiogenetic factors. Plasma ACTH levels decreased with VEGF-inhibitor administration.Subcutaneous transplantation of hESC-derived POs into hypopituitary SCID mice efficaciously renders recipients ACTH-sufficient.Copyright © 2023 Sasaki, Suga, Takeuchi, Nagata, Harada, Kondo, Ito, Maeda, Sakakibara, Soen, Miwata, Asano, Ozaki, Taga, Kuwahara, Nakano, Arima and Saito.

Generation of a variety of organs and tissues from human pluripotent stem cells (hPSCs) has been attempted in vitro. We here present a simple and efficient method for induction of hypothalamic and pituitary tissues from hPSCs. On provision of exogenous agents important for early hypothalamus-pituitary organogenesis, including bone morphogenetic protein 4 and activators of sonic hedgehog, in three-dimensional culture, hPSCs spontaneously form spherical organoids with two distinct tissues, hypothalamus and adenohypophysis. The pituitary tissues derived from hPSCs not only secrete adenocorticotropic hormone, but also retain both positive and negative feedback mechanisms, recapitulating mature endocrine organs in vivo. Furthermore, the results of ectopic transplantation with mouse models of hypopituitarism suggest that these hypothalamus-pituitary organoids have potential as engraftment organs. In addition to their use in transplantation for patients with hypopituitarism they will allow establishment of disease models in vitro and enable research impossible in humans. Hypothalamus-pituitary organoids promise to be a powerful tool in regenerative medicine, drug discovery, and basic research into pituitary development.
Copyright © 2023 Kano, Sasaki, Miwata and Suga.

Human stem cell-derived organoid culture enables the in vitro analysis of the cellular function in three-dimensional aggregates mimicking native organs, and also provides a valuable source of specific cell types in the human body. We previously established organoid models of the hypothalamic-pituitary (HP) complex using human pluripotent stem cells. Although the models are suitable for investigating developmental and functional HP interactions, we consider that isolated pituitary cells are also useful for basic and translational research on the pituitary gland, such as stem cell biology and regenerative medicine. To develop a method for the purification of pituitary cells in HP organoids, we performed surface marker profiling of organoid cells derived from human induced pluripotent stem cells (iPSCs). Screening of 332 human cell surface markers and a subsequent immunohistochemical analysis identified epithelial cell adhesion molecule (EpCAM) as a surface marker of anterior pituitary cells, as well as their ectodermal precursors. EpCAM was not expressed on hypothalamic lineages; thus, anterior pituitary cells were successfully enriched by magnetic separation of EpCAM+ cells from iPSC-derived HP organoids. The enriched pituitary population contained functional corticotrophs and their progenitors; the former responded normally to a corticotropin-releasing hormone stimulus. Our findings would extend the applicability of organoid culture as a novel source of human anterior pituitary cells, including stem/progenitor cells and their endocrine descendants.
Copyright © 2022 Kodani, Kawata, Suga, Kasai, Ozone, Sakakibara, Kuwahara, Taga, Arima, Kameyama, Saito, Nakashima and Nagasaki.

Genomic imprinting refers to the mono-allelic and parent-specific expression of a subset of genes. While long recognized for their role in embryonic development, imprinted genes have recently emerged as important modulators of postnatal physiology, notably through hypothalamus-driven functions. Here, using mouse models of loss, gain and parental inversion of expression, we report that the paternally expressed Zdbf2 gene controls neonatal growth in mice, in a dose-sensitive but parent-of-origin-independent manner. We further found that Zdbf2-KO neonates failed to fully activate hypothalamic circuits that stimulate appetite, and suffered milk deprivation and diminished circulating Insulin Growth Factor 1 (IGF-1). Consequently, only half of Zdbf2-KO pups survived the first days after birth and those surviving were smaller. This study demonstrates that precise imprinted gene dosage is essential for vital physiological functions at the transition from intra- to extra-uterine life, here the adaptation to oral feeding and optimized body weight gain.
© 2022, Glaser et al.

In response to physiological demand, the pituitary gland generates new hormone-secreting cells from committed progenitor cells throughout life. It remains unclear to what extent pituitary stem cells (PSCs), which uniquely express SOX2, contribute to pituitary growth and renewal. Moreover, neither the signals that drive proliferation nor their sources have been elucidated. We have used genetic approaches in the mouse, showing that the WNT pathway is essential for proliferation of all lineages in the gland. We reveal that SOX2+ stem cells are a key source of WNT ligands. By blocking secretion of WNTs from SOX2+ PSCs in vivo, we demonstrate that proliferation of neighbouring committed progenitor cells declines, demonstrating that progenitor multiplication depends on the paracrine WNT secretion from SOX2+ PSCs. Our results indicate that stem cells can hold additional roles in tissue expansion and homeostasis, acting as paracrine signalling centres to coordinate the proliferation of neighbouring cells.
© 2021, Russell et al.