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In the pituitary gland, S100β-positive cells localize in the neurohypophysis and adenohypophysis but the lineage of the two groups remains obscure. S100β is often observed in many neural crest-derived cell types. Therefore, in this study, we investigate the origin of pituitary S100β-positive cells by immunohistochemistry for SOX10, a potent neural crest cell marker, using S100β-green fluorescence protein-transgenic rats. On embryonic day 21.5, a SOX10-positive cell population, which was also positive for the stem/progenitor cell marker SOX2, emerged in the pituitary stalk and posterior lobe and subsequently expanded to create a rostral-caudal gradient on postnatal day 3 (P3). Thereafter, SOX10-positive cells appeared in the intermediate lobe by P15, localizing to the boundary facing the posterior lobe, the gap between the lobule structures and the marginal cell layer, a pituitary stem/progenitor cell niche. Subsequently, there was an increase in SOX10/S100β double-positive cells; some of these cells in the gap between the lobule structures showed extended cytoplasm containing F-actin, indicating a feature of migration activity. The proportion of SOX10-positive cells in the postnatal anterior lobe was lower than 0.025% but about half of them co-localized with the pituitary-specific progenitor cell marker PROP1. Collectively, the present study identified that one of the lineages of S100β-positive cells is a SOX10-positive one and that SOX10-positive cells express pituitary stem/progenitor cell marker genes. [ABSTRACT FROM AUTHOR]

Sox2-expressing stem/progenitor cells in the anterior lobe of the pituitary gland form two types of micro-environments (niches): the marginal cell layer and dense cell clusters in the parenchyma. In relation to the mechanism of regulation of niches, juxtacrine signaling via ephrin and its receptor Eph is known to play important roles in various niches. The ephrin and Eph families are divided into two subclasses to create ephrin/Eph signaling in co-operation with confined partners. Recently, we reported that ephrin-B2 localizes specifically to both pituitary niches. However, the Ephs interacting with ephrin-B2 in these pituitary niches have not yet been identified. Therefore, the present study aims to identify the Ephs interacting with ephrin-B2 and the cells that produce them in the rat pituitary gland. In situ hybridization and immunohistochemistry demonstrated cell type-specific localization of candidate interacting partners for ephrin-B2, including EphA4 in cells located in the posterior lobe, EphB1 in gonadotropes, EphB2 in corticotropes, EphB3 in stem/progenitor cells and EphB4 in endothelial cells in the adult pituitary gland. In particular, double-immunohistochemistry showed cis-interactions between EphB3 and ephrin-B2 in the apical cell membranes of stem/progenitor cell niches throughout life and trans-interactions between EphB2 produced by corticotropes and ephrin-B2 located in the basolateral cell membranes of stem/progenitor cells in the early postnatal pituitary gland. These data indicate that ephrin-B2 plays a role in pituitary stem/progenitor cell niches by selective interaction with EphB3 in cis and EphB2 in trans. [ABSTRACT FROM AUTHOR]

The adenohypophysis comprises six types of endocrine cells, including PIT1-lineage cells such as growth hormone (GH)-producing cells and heterogeneous non-endocrine cells, such as pituitary stem/progenitor cells as a source of endocrine cells. We determine the expression of characteristic stem cell marker genes, including sex-determining region Y-box 2 ( Sox2), in mouse pituitary-derived non-endocrine cell lines Tpit/E, Tpit/F1 and TtT/GF. We observed high expression of fibroblast growth factor (FGF) receptors in Tpit/F1 cells, which we characterised by cultivation in medium containing a basic FGF and B27 supplement as used for neural stem-cell differentiation. A 4-day cultivation of Tpit/F1 produced floating embryonic stem-cell-like clumps accompanied by a three-fold increase in Sox2 expression. Passages in these clumps maintained the proliferative activity and Sox2 expression levels. After 10 days of cultivation, Tpit/F1 cell clumps were immuno-positive for SOX2 and Ki67 (proliferation marker) and loosely attached to the well bottom. An additional 10 days of cultivation induced the emergence of GH-positive/pituitary-specific transcription factor (PIT1)-negative cells showing migration from the clumps. Pit1 overexpression in attached cells could not induce GH production. Finally, we confirmed the presence of PIT1-negative GH-producing cells (3.2-7.7 % of all GH-positive cells) in rat pituitary. Thus, we demonstrate that Tpit/F1 has the plasticity to differentiate into one type of hormone-producing cell. [ABSTRACT FROM AUTHOR]

The pituitary gland, an indispensable endocrine organ that synthesizes and secretes pituitary hormones, develops with the support of many factors. Among them, neuronatin (NNAT), which was discovered in the neonatal mouse brain as a factor involved in neural development, has subsequently been revealed to be coded by an abundantly expressing gene in the pituitary gland but its role remains elusive. We analyze the expression profile of Nnat and the localization of its product during rat pituitary development. The level of Nnat expression was high during the embryonic period but remarkably decreased after birth. Immunohistochemistry demonstrated that NNAT appeared in the SOX2-positive stem/progenitor cells in the developing pituitary primordium on rat embryonic day 11.5 (E11.5) and later in the majority of SOX2/PROP1 double-positive cells on E13.5. Thereafter, during pituitary embryonic development, Nnat expression was observed in some stem/progenitor cells, proliferating cells and terminally differentiating cells. In postnatal pituitaries, NNAT-positive cells decreased in number, with most coexpressing Sox2 or Pit1, suggesting a similar role for NNAT to that during the embryonic period. NNAT was widely localized in mitochondria, peroxisomes and lysosomes, in addition to the endoplasmic reticulum but not in the Golgi. The present study thus demonstrated the variability in expression of NNAT-positive cells in rat embryonic and postnatal pituitaries and the intracellular localization of NNAT. Further investigations to obtain functional evidence for NNAT are a prerequisite. [ABSTRACT FROM AUTHOR]

The published online version contains mistakes in Table 1, Table 2 and Fig. 2. See below for the corrected Tables and Figure. [ABSTRACT FROM AUTHOR]

We have recently shown that cells positive for the paired-related homeobox transcription factors PRRX1 and PRRX2 occur in the rat pituitary, and that they are derived from two different origins: pituitary-derived cells positive for stem cell marker SOX2 and extra-pituitary-derived cells negative for SOX2. In this study, we have further characterized the PRRX1- and PRRX2-positive cells that originate from extra-pituitary cells. Immunohistochemical analyses were performed with specific antibodies against PRRX1 and PRRX2 in order to clarify their roles in pituitary vasculogenesis. PRRX1- and PRRX2-positive cells were found in Atwell's recess and at the periphery of the pituitary on embryonic day 15.5 (E15.5). Several PRRX1-positive cells then invaded the anterior lobe, together with a few PRRX2-positive cells, on E16.5. Some PRRX1-positive cells were also positive for mesenchymal stem cell marker NESTIN. Moreover, some PRRX1/NESTIN double-positive cells showed characteristics of vascular endothelial cells with an Isolectin-B4-binding capacity. PRRX1 co-localized with vascular smooth muscle cell/pericyte marker α-smooth muscle actin in the deep area of Atwell's recess. We confirmed the presence of PRRX2/NESTIN double-positive cells at an entry area in Atwell's recess and at the periphery of the pituitary, but PRRX2 did not co-localize with Isolectin B4 or α-smooth muscle actin. These data suggest that PRRX1- and PRRX2-positive mesenchymal stem/progenitor cells are present at the periphery of the embryonic pituitary and at the entry from Atwell's recess and participate in pituitary vasculogenesis by differentiation into vascular endothelial cells and pericytes, whereas the presence of PRRX2 indicates much higher stemness than PRRX1. [ABSTRACT FROM AUTHOR]

We have recently reported that Sox2-expressing pituitary stem/progenitor cells contact each other via a tight-junction protein CAR to form stem/progenitor cell niches in the marginal cell layer facing the lumen and in the clusters scattered in the parenchyma of the anterior lobe. However, the microenvironment of the niche for the maintenance of stem cell function in the pituitary remains obscure. In this study of pituitary stem/progenitor cell niches, we have attempted to identify the expression of juxtacrine factor ephrin and its receptor. We have found that ephrin-B2 is expressed in the pituitary throughout development but changes its localization pattern. Notably, in the adult pituitary, ephrin-B2 immuno-signals occur in SOX2-, E-cadherin-, and CAR-triple-positive stem/progenitor cells in the niches. Our data suggest that ephrin-B2 signaling has an important role in the formation of pituitary stem/progenitor cell niches and in pituitary organogenesis. [ABSTRACT FROM AUTHOR]

Some non-endocrine cells in the pituitary anterior lobe are responsible for providing stem/progenitor cells to maintain hormone-producing cells. In particular, cells expressing S100β protein, a calcium-binding protein, have been hypothesized to be a pituitary cell resource. Accumulating data have revealed that S100β-positive cells comprise heterogeneous populations and some of them certainly show stem/progenitor characteristics in vivo. Hence, we examine whether S100β-positive cells have the capacity to differentiate into endocrine cells, by means of in vivo and in vitro experiments on transgenic rats expressing enhanced green fluorescent protein (EGFP) under the control of the S100β promoter. Immunohistochemistry of the pituitary confirmed that some S100β-positive cells expressed SOX2 (SRY [sex-determining region Y]-box 2) and had proliferative activity. Dispersed anterior lobe cells were observed by time-lapse microscopy, followed by immunostaining for hormone and pituitary-transcription-factor1 (PIT1). First, the dispersed anterior lobe cells were immunostained by an antibody against SOX2. S100β-protein co-localizes with SOX2 (about 89 %). Although 44 of 134 S100β-positive cells traced were proliferative but negative to any hormones, 14 cells were positive for one of the pituitary hormones and/or PIT1, confirming the presence of all types of hormone-producing cells. Notably, GFP-fluorescence appeared in two hormone-positive cells during culture. On the other hand, we observed hormone-producing cells that were not positive for S100β at the end of the time-lapse study, despite being initially positive. These findings suggest that S100β-positive cells cultured from the anterior lobe are capable of developing into hormone-producing cells, although this happens relatively infrequently. [ABSTRACT FROM AUTHOR]

Variants of GRIN1, which encodes GluN1, are associated with developmental delay, epilepsy, and cortical malformation. Here, we report a case of arthrogryposis multiplex congenita with polymicrogyria and infantile encephalopathy caused by a heterozygous variant, c.1949A>C, p.(Asn650Thr) of GRIN1, which could result in the disruption of the third transmembrane domain (M3) of GluN1. This case expands our understanding of the known phenotypes of GRIN1-related neurodevelopmental disorders. [ABSTRACT FROM AUTHOR]

The published online version contains mistake in Table 1, Table 2, and some data in Materials and Methods. [ABSTRACT FROM AUTHOR]