Lhx4 and Prop1 are required for cell survival and expansion of the pituitary primordia

Development ◽  
2002 ◽  
Vol 129 (18) ◽  
pp. 4229-4239 ◽  
Author(s):  
Lori T. Raetzman ◽  
Robert Ward ◽  
Sally A. Camper

Deficiencies in the homeobox transcription factors LHX4 and PROP1 cause pituitary hormone deficiency in both humans and mice. Lhx4 and Prop1 mutants exhibit severe anterior pituitary hypoplasia resulting from limited differentiation and expansion of most specialized cell types. Little is known about the mechanism through which these genes promote pituitary development. In this study we determined that the hypoplasia in Lhx4 mutants results from increased cell death and that the reduced differentiation is attributable to a temporal shift in Lhx3 activation. In contrast, Prop1 mutants exhibit normal cell proliferation and cell survival but show evidence of defective dorsal-ventral patterning. Molecular genetic analyses reveal that Lhx4 and Prop1 have overlapping functions in early pituitary development. Double mutants exhibit delayed corticotrope specification and complete failure of all other anterior pituitary cell types to differentiate. Thus, Lhx4 and Prop1 have critical, but mechanistically different roles in specification and expansion of specialized anterior pituitary cells.

2021 ◽  
Author(s):  
Shigeru Suzuki ◽  
Kumihiro Matsuo ◽  
Yoshiya Ito ◽  
Atsushi Kobayashi ◽  
Takahide Kokumai ◽  
...  

Background: POU1F1 encodes both PIT-1α, which plays pivotal roles in pituitary development and GH, PRL and TSHB expression, and the alternatively spliced isoform PIT-1β, which contains an insertion of 26-amino acids (β-domain) in the transactivation domain of PIT-1α due to the use of an alternative splice acceptor at the end of the first intron. PIT-1β is expressed at much lower levels than PIT-1α and represses endogenous PIT-1α transcriptional activity. Although POU1F1 mutations lead to combined pituitary hormone deficiency (CPHD), no patients with β-domain mutations have been reported. Results: Here, we report that a three-generation family exhibited different degrees of CPHD, including growth hormone deficiency with intrafamilial variability of prolactin/TSH insufficiency and unexpected prolactinoma occurrence. The CPHD was due to a novel POU1F1 heterozygous variant (c.143-69T>G) in intron 1 of PIT-1α (RefSeq number NM_000306) or as c.152T>G (p.Ile51Ser) in exon 2 of PIT-1β (NM_001122757). Gene splicing experiments showed that this mutation yielded the PIT-1β transcript without other transcripts. Lymphocyte PIT-1β mRNA expression was significantly higher in the patients with the heterozygous mutation than a control. A luciferase reporter assay revealed that the PIT-1β-Ile51Ser mutant repressed PIT-1α and abolished transactivation capacity for the rat prolactin promoter in GH3 pituitary cells. Conclusions: We describe, for the first time, that PIT-1β mutation can cause CPHD through a novel genetic mechanism, such as PIT-1β overexpression, and that POU1F1 mutation might be associated with a prolactinoma. Analysis of new patients and long-term follow-up are needed to clarify the characteristics of PIT-1β mutations.


2015 ◽  
Vol 29 (4) ◽  
pp. 597-612 ◽  
Author(s):  
Peter Gergics ◽  
Michelle L. Brinkmeier ◽  
Sally A. Camper

Abstract Defects in the Lhx4, Lhx3, and Pitx2 genes can cause combined pituitary hormone deficiency and pituitary hypoplasia in both humans and mice. Not much is known about the mechanism underlying hypoplasia in these mutants beyond generally increased cell death and poorly maintained proliferation. We identified both common and unique abnormalities in developmental regulation of key cell cycle regulator gene expression in each of these three mutants. All three mutants exhibit reduced expression of the proliferative marker Ki67 and the transitional marker p57. We discovered that expression of the cyclin-dependent kinase inhibitor 1a (Cdkn1a or p21) is expanded dorsally in the pituitary primordium of both Lhx3 and Lhx4 mutants. Uniquely, Lhx4 mutants exhibit reduced cyclin D1 expression and have auxiliary pouch-like structures. We show evidence for indirect and direct effects of LHX4 on p21 expression in αT3-1 pituitary cells. In summary, Lhx4 is necessary for efficient pituitary progenitor cell proliferation and restriction of p21 expression.


2007 ◽  
Vol 157 (suppl_1) ◽  
pp. S3-S14 ◽  
Author(s):  
Daniel Kelberman ◽  
Mehul Tulsidas Dattani

The anterior pituitary gland is a central regulator of growth, reproduction and homeostasis, and is the end-product of a carefully orchestrated pattern of expression of signalling molecules and transcription factors leading to the development of this complex organ secreting six hormones from five different cell types. Naturally occurring and transgenic murine models have demonstrated a role for many of these molecules in the aetiology of combined pituitary hormone deficiency (CPHD). These include the transcription factors HESX1, PROP1, POU1F1, LHX3, LHX4, TBX19, SOX2 and SOX3. The expression pattern of these transcription factors dictates the phenotype that results when the gene encoding the relevant transcription factor is mutated. The highly variable phenotype may consist of isolated hypopituitarism, or more complex disorders such as septo-optic dysplasia and holoprosencephaly. Since mutations in any one transcription factor are uncommon, and since the overall incidence of mutations in known transcription factors is low in patients with CPHD, it is clear that many genes remain to be identified, and the characterization of these will further elucidate the pathogenesis of these complex conditions and also shed light on normal pituitary development.


2021 ◽  
pp. 1-9
Author(s):  
Elisa Vaiani ◽  
Guido Felizzia ◽  
Fabiana Lubieniecki ◽  
Jorge Braier ◽  
Alicia Belgorosky

Langerhans cell histiocytosis (LCH) is a disorder of the mononuclear phagocyte system that can affect almost any organ and system. The most common central nervous system (CNS) manifestation in LCH is the infiltration of the hypothalamic-pituitary region leading to destruction and neurodegeneration of CNS tissue. The latter causes the most frequent endocrinological manifestation, that is, central diabetes insipidus (CDI), and less often anterior pituitary hormone deficiency (APD). The reported incidence of CDI is estimated between 11.5 and 24% and is considered a risk factor for neurodegenerative disease and APD. Three risk factors for development of CDI are recognized in the majority of the studies: (1) multisystem disease, (2) the occurrence of reactivations or active disease for a prolonged period, and (3) the presence of craniofacial bone lesions. Since CDI may occur as the first manifestation of LCH, differential diagnosis of malignant diseases like germ cell tumours must be made. APD is almost always associated with CDI and can appear several years after the diagnosis of CDI. Growth hormone is the most commonly affected anterior pituitary hormone. Despite significant advances in the knowledge of LCH in recent years, little progress has been made in preventing long-term sequelae such as those affecting the hypothalamic-pituitary system.


1988 ◽  
Vol 139 (1) ◽  
pp. 287-316
Author(s):  
W. T. Mason ◽  
S. R. Rawlings ◽  
P. Cobbett ◽  
S. K. Sikdar ◽  
R. Zorec ◽  
...  

Normal anterior pituitary cells, in their diversity and heterogeneity, provide a rich source of models for secretory function. However, until recently they have largely been neglected in favour of neoplastic, clonal tumour cell lines of pituitary origin, which have enabled a number of studies on supposedly homogeneous cell types. Because many of these lines appear to lack key peptide and neurotransmitter receptors, as well as being degranulated with accompanying abnormal levels of secretion, we have developed a range of normal primary anterior pituitary cell cultures using dispersion and enrichment techniques. By studying lactotrophs, somatotrophs and gonadotrophs we have revealed a number of possible transduction mechanisms by which receptors for hypothalamic peptides and neurotransmitters may control secretion. In particular, the transduction events controlling secretion from pituitary cells may differ fundamentally from those found in other cell types. Patch-clamp recordings in these various pituitary cell preparations have revealed substantial populations of voltage-dependent Na+, Ca2+ and K+ channels which may support action potentials in these cells. Although activation of these channels may gate Ca2+ entry to the cells under some conditions, our evidence taken with that of other laboratories suggests that peptide-receptor interactions leading to hormone secretion occur independently of significant membrane depolarization. Rather, secretion of hormone and rises in intracellular calcium measured with new probes for intracellular calcium activity, can occur in response to hypothalamic peptide activation in the absence of substantial changes in membrane potential. These changes in intracellular calcium activity almost certainly depend on both intracellular and extracellular calcium sources. In addition, strong evidence of a role for multiple intracellular receptors and modulators in the secretory event suggests we should consider the plasma membrane channels important for regulation of hormone secretion to be predominantly agonist-activated, rather than of the more conventional voltage-dependent type. Likewise, evidence from new methods for recording single ion channels suggests the existence of intracellular sites for channel modulation, implying they too may play an important role in secretory regulation. We shall consider new data and new technology which we hope will provide key answers to the many intriguing questions surrounding the control of pituitary hormone secretion. We shall highlight our work with recordings of single ion channels activated by peptides, and recent experiments using imaging of intracellular ionized free calcium.(ABSTRACT TRUNCATED AT 250 WORDS)


Author(s):  
Mark Oette ◽  
Marvin J. Stone ◽  
Hendrik P. N. Scholl ◽  
Peter Charbel Issa ◽  
Monika Fleckenstein ◽  
...  

Development ◽  
1996 ◽  
Vol 122 (1) ◽  
pp. 151-160 ◽  
Author(s):  
P.J. Gage ◽  
M.L. Roller ◽  
T.L. Saunders ◽  
L.M. Scarlett ◽  
S.A. Camper

The Ames dwarf mouse transmits a recessive mutation (df) resulting in a profound anterior pituitary hypocellularity due to a general lack of thyrotropes, somatotropes and lactotropes. These cell types are also dependent on the pituitary-specific transcription factor, Pit-1. We present evidence that expression of Pit-1 and limited commitment to these cells lineages occurs in df/df pituitaries. Thus, the crucial role of df may be in lineage-specific proliferation, rather than cytodifferentiation. The presence of all three Pit-1-dependent cell types in clonally derived clusters provides compelling evidence that these three lineages share a common, pluripotent precursor cell. Clusters containing different combinations of Pit-1-dependent cell types suggests that the Pit-1+ precursor cells choose from multiple developmental options during ontogeny. Characterization of df/df<-->+/+ chimeric mice demonstrated that df functions by a cell-autonomous mechanism. Therefore, df and Pit-1 are both cell-autonomous factors required for thyrotrope, somatotrope and lactotrope ontogeny, but their relative roles are different.


Medicina ◽  
2009 ◽  
Vol 45 (9) ◽  
pp. 693 ◽  
Author(s):  
Natalija Tkačenko ◽  
Danutė Lašienė ◽  
Silvija Jakštienė ◽  
Algidas Basevičius ◽  
Rasa Verkauskienė

The most common genetically determined cause of multiple pituitary hormone deficiency is PROP-1 gene mutation. PROP-1 is a transcription factor involved in the development of pituitary gland and affects hormonal synthesis of anterior pituitary. The aim of our study was to evaluate radiological aspects of the pituitary region in patients with PROP-1 gene mutation. Pituitary imaging studies were performed in 12 patients with a confirmed PROP-1 gene mutation. Pituitary hyperplasia was found in 5 (42%) and pituitary hypoplasia in 4 (33%) patients. Changes in pituitary size were not associated with the type of PROP-1 gene mutation.


2020 ◽  
Vol 4 (Supplement_1) ◽  
Author(s):  
Frederique Murielle Ruf-Zamojski ◽  
Michel A Zamojski ◽  
German Nudelman ◽  
Yongchao Ge ◽  
Natalia Mendelev ◽  
...  

Abstract The pituitary gland is a critical regulator of the neuroendocrine system. To further our understanding of the classification, cellular heterogeneity, and regulatory landscape of pituitary cell types, we performed and computationally integrated single cell (SC)/single nucleus (SN) resolution experiments capturing RNA expression, chromatin accessibility, and DNA methylation state from mouse dissociated whole pituitaries. Both SC and SN transcriptome analysis and promoter accessibility identified the five classical hormone-producing cell types (somatotropes, gonadotropes (GT), lactotropes, thyrotropes, and corticotropes). GT cells distinctively expressed transcripts for Cga, Fshb, Lhb, Nr5a1, and Gnrhr in SC RNA-seq and SN RNA-seq. This was matched in SN ATAC-seq with GTs specifically showing open chromatin at the promoter regions for the same genes. Similarly, the other classically defined anterior pituitary cells displayed transcript expression and chromatin accessibility patterns characteristic of their own cell type. This integrated analysis identified additional cell-types, such as a stem cell cluster expressing transcripts for Sox2, Sox9, Mia, and Rbpms, and a broadly accessible chromatin state. In addition, we performed bulk ATAC-seq in the LβT2b gonadotrope-like cell line. While the FSHB promoter region was closed in the cell line, we identified a region upstream of Fshb that became accessible by the synergistic actions of GnRH and activin A, and that corresponded to a conserved region identified by a polycystic ovary syndrome (PCOS) single nucleotide polymorphism (SNP). Although this locus appears closed in deep sequencing bulk ATAC-seq of dissociated mouse pituitary cells, SN ATAC-seq of the same preparation showed that this site was specifically open in mouse GT, but closed in 14 other pituitary cell type clusters. This discrepancy highlighted the detection limit of a bulk ATAC-seq experiment in a subpopulation, as GT represented ~5% of this dissociated anterior pituitary sample. These results identified this locus as a candidate for explaining the dual dependence of Fshb expression on GnRH and activin/TGFβ signaling, and potential new evidence for upstream regulation of Fshb. The pituitary epigenetic landscape provides a resource for improved cell type identification and for the investigation of the regulatory mechanisms driving cell-to-cell heterogeneity. Additional authors not listed due to abstract submission restrictions: N. Seenarine, M. Amper, N. Jain (ISMMS).


1984 ◽  
Vol 32 (12) ◽  
pp. 1285-1294 ◽  
Author(s):  
A M Cataldo ◽  
R D Broadwell

The endoplasmic reticulum (ER) and glycogen in secretory cells of anterior pituitary glands from control and fasted mice were investigated ultrastructurally using cytochemical staining techniques. Potential enzyme cytochemical markers for the ER included glucose-6-phosphatase (G6Pase) and nucleoside diphosphatase (NDPase) activities. Presumptive glycogen particles were identified in tissue postfixed in 1% osmium tetroxide-1.5% potassium ferrocyanide or in ultrathin sections poststained with periodic acid-thiocarbohydrazide-silver proteinate. The ER appeared to be related structurally and cytochemically to the nuclear envelope and cis Golgi saccules. Similar relationships between the ER and the trans Golgi saccules or GERL were not observed. In anterior pituitary glands from control mice, G6Pase activity was prominent within the lumen of the ER, nuclear envelope, and cis Golgi saccules of all cells; reaction product was absent in the trans Golgi saccules and in GERL. G6Pase activity was sparse to non-existent in anterior pituitary cells from fasted mice. The cytochemical reaction utilizing the Gomori lead capture method indicated that G6Pase in anterior pituitary cells may function as a phosphohydrolase for converting glucose-6-phosphate to glucose. Cytochemical localization of NDPase activity was not evident in the ER; reaction product was localized consistently in one or two trans Golgi saccules and occasionally in GERL and nascent secretory granules. Presumptive glycogen particles in each of the different secretory cell types from control mice appeared as 20-30 nm wide, electron-dense particles scattered as single entities throughout the cytoplasm. Anterior pituitary glands from fasted mice exhibited conspicuous and numerous clumps of glycogen particles in addition to scattered particles in all cell types except corticotrophs, which appeared to be devoid of glycogen. Glycogen particles were absent in anterior pituitary cells incubated in a medium containing diastase. Our results suggest that in anterior pituitary cells of the mouse: 1) the phosphohydrolytic activity of G6Pase is a reliable cytochemical marker for the ER; 2) the ER is associated morphologically and cytochemically with the cis face but not with the trans face of the Golgi apparatus or with GERL; 3) some glucose-6-phosphate, a possible substrate for G6Pase in vivo, may be derived indirectly from glycogen stores; and 4) modulations in G6Pase activity and glycogen storage during fasting may reflect an alteration in energy metabolism.


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