RESUMO
The primary cilium is an essential organelle that is important for normal cell signalling during development and homeostasis but its role in pituitary development has not been reported. The primary cilium facilitates signal transduction for multiple pathways, the best-characterised being the SHH pathway, which is known to be necessary for correct pituitary gland development. FUZ is a planar cell polarity (PCP) effector that is essential for normal ciliogenesis, where the primary cilia of Fuz-/- mutants are shorter or non-functional. FUZ is part of a group of proteins required for recruiting retrograde intraflagellar transport proteins to the base of the organelle. Previous work has reported ciliopathy phenotypes in Fuz-/- homozygous null mouse mutants, including neural tube defects, craniofacial abnormalities, and polydactyly, alongside PCP defects including kinked/curly tails and heart defects. Interestingly, the pituitary gland was reported to be missing in Fuz-/- mutants at 14.5 dpc but the mechanisms underlying this phenotype were not investigated. Here, we have analysed the pituitary development of Fuz-/- mutants. Histological analyses reveal that Rathke's pouch (RP) is initially induced normally but is not specified and fails to express LHX3, resulting in hypoplasia and apoptosis. Characterisation of SHH signalling reveals reduced pathway activation in Fuz-/- mutant relative to control embryos, leading to deficient specification of anterior pituitary fate. Analyses of the key developmental signals FGF8 and BMP4, which are influenced by SHH, reveal abnormal patterning in the ventral diencephalon, contributing further to abnormal RP development. Taken together, our analyses suggest that primary cilia are required for normal pituitary specification through SHH signalling.
Assuntos
Polaridade Celular , Cílios , Animais , Camundongos , Cílios/fisiologia , Proteínas Hedgehog/metabolismo , Camundongos Knockout , Hipófise/metabolismo , Proteínas/metabolismoRESUMO
Stem cells in the anterior pituitary gland can give rise to all resident endocrine cells and are integral components for the appropriate development and subsequent maintenance of the organ. Located in discreet niches within the gland, stem cells are involved in bi-directional signalling with their surrounding neighbours, interactions which underpin pituitary gland homeostasis and response to organ challenge or physiological demand. In this review we highlight core signalling pathways that steer pituitary progenitors towards specific endocrine fate decisions throughout development. We further elaborate on those which are conserved in the stem cell niche postnatally, including WNT, YAP/TAZ and Notch signalling. Furthermore, we have collated a directory of single cell RNA sequencing studies carried out on pituitaries across multiple organisms, which have the potential to provide a vast database to study stem cell niche components in an unbiased manner. Reviewing published data, we highlight that stem cells are one of the main signalling hubs within the anterior pituitary. In future, coupling single cell sequencing approaches with genetic manipulation tools in vivo, will enable elucidation of how previously understudied signalling pathways function within the anterior pituitary stem cell niche.
Assuntos
Doenças da Hipófise , Nicho de Células-Tronco , Humanos , Nicho de Células-Tronco/genética , Hipófise , Comunicação Celular , Transdução de SinaisRESUMO
The Australian Institute of Health and Welfare (AIHW) has been providing support to the Australian Government Department of Health to report on mental health-related data to Australian governments on a frequent basis since April 2020 in the form of COVID-19 mental health services data dashboards. These dashboards feature extensive use of data visualizations which illustrate the change in mental health service use over time as well as comparisons with pre-pandemic levels of service use. Data are included from the Medicare Benefits Schedule (MBS), Pharmaceutical Benefits Scheme (PBS/RPBS), Australian Government-funded crisis and support organizations, and key findings from emerging research. Demand for telehealth, crisis and support organizations and online mental health information services, in particular, have increased during the pandemic. The dashboards incorporate both new and existing data sources and represent an innovative way of reporting mental health services data to Australian governments. The reporting has enabled timely, targeted adjustments to mental health service delivery during the pandemic with improved cooperative data sharing arrangements having the potential to yield ongoing benefits.
Assuntos
COVID-19 , Serviços de Saúde Mental , Idoso , Austrália , Governo , Humanos , Medicare , SARS-CoV-2 , Estados UnidosRESUMO
In mammals, imprinted genes regulate many critical endocrine processes such as growth, the onset of puberty and maternal reproductive behaviour. Human imprinting disorders (IDs) are caused by genetic and epigenetic mechanisms that alter the expression dosage of imprinted genes. Due to improvements in diagnosis, increasing numbers of patients with IDs are now identified and monitored across their lifetimes. Seminal work has revealed that IDs have a strong endocrine component, yet the contribution of imprinted gene products in the development and function of the hypothalamo-pituitary axis are not well defined. Postnatal endocrine processes are dependent upon the production of hormones from the pituitary gland. While the actions of a few imprinted genes in pituitary development and function have been described, to date there has been no attempt to link the expression of these genes as a class to the formation and function of this essential organ. This is important because IDs show considerable overlap, and imprinted genes are known to define a transcriptional network related to organ growth. This knowledge deficit is partly due to technical difficulties in obtaining useful transcriptomic data from the pituitary gland, namely, its small size during development and cellular complexity in maturity. Here we utilise high-sensitivity RNA sequencing at the embryonic stages, and single-cell RNA sequencing data to describe the imprinted transcriptome of the pituitary gland. In concert, we provide a comprehensive literature review of the current knowledge of the role of imprinted genes in pituitary hormonal pathways and how these relate to IDs. We present new data that implicate imprinted gene networks in the development of the gland and in the stem cell compartment. Furthermore, we suggest novel roles for individual imprinted genes in the aetiology of IDs. Finally, we describe the dynamic regulation of imprinted genes in the pituitary gland of the pregnant mother, with implications for the regulation of maternal metabolic adaptations to pregnancy.
Assuntos
Perfilação da Expressão Gênica/métodos , Redes Reguladoras de Genes , Impressão Genômica , Hipófise/crescimento & desenvolvimento , Animais , Metilação de DNA , Feminino , Regulação da Expressão Gênica no Desenvolvimento , Humanos , Camundongos , Hipófise/química , Gravidez , Análise de Sequência de RNA , Análise de Célula Única/métodosRESUMO
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.
Assuntos
Comunicação Parácrina , Hipófise/fisiologia , Células-Tronco/fisiologia , Via de Sinalização Wnt , Animais , Diferenciação Celular , Proliferação de Células , Feminino , Masculino , CamundongosRESUMO
Pituitary developmental defects lead to partial or complete hormone deficiency and significant health problems. The majority of cases are sporadic and of unknown cause. We screened 28 patients with pituitary stalk interruption syndrome (PSIS) for mutations in the FAT/DCHS family of protocadherins that have high functional redundancy. We identified seven variants, four of which putatively damaging, in FAT2 and DCHS2 in six patients with pituitary developmental defects recruited through a cohort of patients with mostly ectopic posterior pituitary gland and/or pituitary stalk interruption. All patients had growth hormone deficiency and two presented with multiple hormone deficiencies and small glands. FAT2 and DCHS2 were strongly expressed in the mesenchyme surrounding the normal developing human pituitary. We analyzed Dchs2-/- mouse mutants and identified anterior pituitary hypoplasia and partially penetrant infundibular defects. Overlapping infundibular abnormalities and distinct anterior pituitary morphogenesis defects were observed in Fat4-/- and Dchs1-/- mouse mutants but all animal models displayed normal commitment to the anterior pituitary cell type. Together our data implicate FAT/DCHS protocadherins in normal hypothalamic-pituitary development and identify FAT2 and DCHS2 as candidates underlying pituitary gland developmental defects such as ectopic pituitary gland and/or pituitary stalk interruption.
Assuntos
Proteínas Relacionadas a Caderinas/genética , Caderinas/genética , Doenças da Hipófise/genética , Adolescente , Animais , Proteínas Relacionadas a Caderinas/metabolismo , Caderinas/metabolismo , Feminino , Humanos , Hipotálamo/crescimento & desenvolvimento , Hipotálamo/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Mutação , Hipófise/crescimento & desenvolvimento , Hipófise/metabolismo , Adulto JovemRESUMO
SOX2 positive pituitary stem cells (PSCs) are specified embryonically and persist throughout life, giving rise to all pituitary endocrine lineages. We have previously shown the activation of the STK/LATS/YAP/TAZ signalling cascade in the developing and postnatal mammalian pituitary. Here, we investigate the function of this pathway during pituitary development and in the regulation of the SOX2 cell compartment. Through loss- and gain-of-function genetic approaches, we reveal that restricting YAP/TAZ activation during development is essential for normal organ size and specification from SOX2+ PSCs. Postnatal deletion of LATS kinases and subsequent upregulation of YAP/TAZ leads to uncontrolled clonal expansion of the SOX2+ PSCs and disruption of their differentiation, causing the formation of non-secreting, aggressive pituitary tumours. In contrast, sustained expression of YAP alone results in expansion of SOX2+ PSCs capable of differentiation and devoid of tumourigenic potential. Our findings identify the LATS/YAP/TAZ signalling cascade as an essential component of PSC regulation in normal pituitary physiology and tumourigenesis.
Assuntos
Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Proteínas de Ciclo Celular/metabolismo , Proliferação de Células , Hipófise/citologia , Proteínas Serina-Treonina Quinases/metabolismo , Transdução de Sinais , Células-Tronco/fisiologia , Transativadores/metabolismo , Proteínas Supressoras de Tumor/metabolismo , Animais , Deleção de Genes , Redes Reguladoras de Genes , Camundongos , Hipófise/embriologia , Hipófise/crescimento & desenvolvimento , Fatores de Transcrição SOXB1/análise , Células-Tronco/química , Proteínas de Sinalização YAPRESUMO
Tumours of the anterior pituitary can manifest from all endocrine cell types but the mechanisms for determining their specification are not known. The Hippo kinase cascade is a crucial signalling pathway regulating growth and cell fate in numerous organs. There is mounting evidence implicating this in tumour formation, where it is emerging as an anti-cancer target. We previously demonstrated activity of the Hippo kinase cascade in the mouse pituitary and nuclear association of its effectors YAP/TAZ with SOX2-expressing pituitary stem cells. Here, we sought to investigate whether these components are expressed in the human pituitary and if they are deregulated in human pituitary tumours. Analysis of pathway components by immunofluorescence reveals pathway activity during normal human pituitary development and in the adult gland. Poorly differentiated pituitary tumours (null-cell adenomas, adamantinomatous craniopharyngiomas (ACPs) and papillary craniopharyngiomas (PCPs)), displayed enhanced expression of pathway effectors YAP/TAZ. In contrast, differentiated adenomas displayed lower or absent levels. Knockdown of the kinase-encoding Lats1 in GH3 rat mammosomatotropinoma cells suppressed Prl and Gh promoter activity following an increase in YAP/TAZ levels. In conclusion, we have demonstrated activity of the Hippo kinase cascade in the human pituitary and association of high YAP/TAZ with repression of the differentiated state both in vitro and in vivo. Characterisation of this pathway in pituitary tumours is of potential prognostic value, opening up putative avenues for treatments.
Assuntos
Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Proteínas Reguladoras de Apoptose/metabolismo , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Hipófise/metabolismo , Neoplasias Hipofisárias/metabolismo , Transativadores/metabolismo , Fatores de Transcrição/metabolismo , Idoso , Idoso de 80 Anos ou mais , Animais , Linhagem Celular Tumoral , Feminino , Humanos , Masculino , Neoplasias Hipofisárias/genética , Proteínas Serina-Treonina Quinases/genética , Interferência de RNA , Ratos , Proteínas com Motivo de Ligação a PDZ com Coativador Transcricional , Proteínas de Sinalização YAPRESUMO
As a central regulator of major physiological processes, the pituitary gland is a highly dynamic organ, capable of responding to hormonal demand and hypothalamic influence, through adapting secretion as well as remodelling cell numbers among its seven populations of differentiated cells. Stem cells of the pituitary have been shown to actively generate new cells during postnatal development but remain mostly quiescent during adulthood, where they persist as a long-lived population. Despite a significant body of research characterising attributes of anterior pituitary stem cells, the regulation of this population is poorly understood. A better grasp on the signalling mechanisms influencing stem proliferation and cell fate decisions can impact on our future treatments of pituitary gland disorders such as organ failure and pituitary tumours, which can disrupt endocrine homeostasis with life-long consequences. This minireview addresses the current methodologies aiming to understand better the attributes of pituitary stem cells and the normal regulation of this population in the organ, and discusses putative future avenues to manipulate pituitary stem cells during disease states or regenerative medicine approaches.
Assuntos
Hipófise , Células-Tronco , Animais , HumanosRESUMO
Familial growth hormone deficiency provides an opportunity to identify new genetic causes of short stature. Here we combine linkage analysis with whole-genome resequencing in patients with growth hormone deficiency and maternally inherited gingival fibromatosis. We report that patients from three unrelated families harbor either of two missense mutations, c.347G>T p.(Arg116Leu) or c.1106C>T p.(Pro369Leu), in KCNQ1, a gene previously implicated in the long QT interval syndrome. Kcnq1 is expressed in hypothalamic GHRH neurons and pituitary somatotropes. Co-expressing KCNQ1 with the KCNE2 ß-subunit shows that both KCNQ1 mutants increase current levels in patch clamp analyses and are associated with reduced pituitary hormone secretion from AtT-20 cells. In conclusion, our results reveal a role for the KCNQ1 potassium channel in the regulation of human growth, and show that growth hormone deficiency associated with maternally inherited gingival fibromatosis is an allelic disorder with cardiac arrhythmia syndromes caused by KCNQ1 mutations.
Assuntos
Fibromatose Gengival/genética , Hormônio do Crescimento Humano/deficiência , Canal de Potássio KCNQ1/genética , Mutação de Sentido Incorreto , Adolescente , Hormônio Adrenocorticotrópico/metabolismo , Adulto , Alelos , Substituição de Aminoácidos , Animais , Arritmias Cardíacas/genética , Criança , Pré-Escolar , Feminino , Fibromatose Gengival/metabolismo , Humanos , Canal de Potássio KCNQ1/química , Canal de Potássio KCNQ1/metabolismo , Masculino , Herança Materna/genética , Camundongos , Pessoa de Meia-Idade , Modelos Moleculares , Linhagem , Mapas de Interação de Proteínas , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Adulto JovemRESUMO
Sonic hedgehog (SHH) is an essential morphogenetic signal that dictates cell fate decisions in several developing organs in mammals. In vitro data suggest that SHH is required to specify LHX3+/LHX4+ Rathke's pouch (RP) progenitor identity. However, in vivo studies have failed to reveal such a function, supporting instead a crucial role for SHH in promoting proliferation of these RP progenitors and for differentiation of pituitary cell types. Here, we have used a genetic approach to demonstrate that activation of the SHH pathway is necessary to induce LHX3+/LHX4+ RP identity in mouse embryos. First, we show that conditional deletion of Shh in the anterior hypothalamus results in a fully penetrant phenotype characterised by a complete arrest of RP development, with lack of Lhx3/Lhx4 expression in RP epithelium at 9.0â days post coitum (dpc) and total loss of pituitary tissue by 12.5â dpc. Conversely, overactivation of the SHH pathway by conditional deletion of Ptch1 in RP progenitors leads to severe hyperplasia and enlargement of the Sox2+ stem cell compartment by the end of gestation.
Assuntos
Linhagem da Célula , Proteínas Hedgehog/metabolismo , Hipotálamo/embriologia , Hipotálamo/metabolismo , Proteínas com Homeodomínio LIM/metabolismo , Hipófise/embriologia , Hipófise/metabolismo , Fatores de Transcrição/metabolismo , Compartimento Celular , Contagem de Células , Diferenciação Celular , Proliferação de Células , Células Clonais , Cruzamentos Genéticos , Ectoderma/embriologia , Ectoderma/metabolismo , Embrião de Mamíferos/metabolismo , Endoderma/embriologia , Endoderma/metabolismo , Epitélio/embriologia , Epitélio/metabolismo , Feminino , Regulação da Expressão Gênica no Desenvolvimento , Genótipo , Proteínas Hedgehog/genética , Humanos , Masculino , Mutação/genética , Hipófise/patologia , Transdução de Sinais , Células-TroncoRESUMO
We investigated the corneal morphology of adult Mp/+ mice, which are heterozygous for the micropinna microphthalmia mutation, and identified several abnormalities, which implied that corneal epithelial maintenance was abnormal. The Mp/+ corneal epithelium was thin, loosely packed and contained goblet cells in older mice. Evidence also suggested that the barrier function was compromised. However, there was no major effect on corneal epithelial cell turnover and mosaic patterns of radial stripes indicated that radial cell movement was normal. Limbal blood vessels formed an abnormally wide limbal vasculature ring, K19-positive cells were distributed more widely than normal and K12 was weakly expressed in the peripheral cornea. This raises the possibilities that the limbal-corneal boundary was poorly defined or the limbus was wider than normal. BrdU label-retaining cell numbers and quantitative clonal analysis suggested that limbal epithelial stem cell numbers were not depleted and might be higher than normal. However, as corneal epithelial homeostasis was abnormal, it is possible that Mp/+ stem cell function was impaired. It has been shown recently that the Mp mutation involves a chromosome 18 inversion that disrupts the Fbn2 and Isoc1 genes and produces an abnormal, truncated fibrillin-2(MP) protein. This abnormal protein accumulates in the endoplasmic reticulum (ER) of cells that normally express Fbn2 and causes ER stress. It was also shown that Fbn2 is expressed in the corneal stroma but not the corneal epithelium, suggesting that the presence of truncated fibrillin-2(MP) protein in the corneal stroma disrupts corneal epithelial homeostasis in Mp/+ mice.
Assuntos
Epitélio Corneano/anormalidades , Microftalmia/genética , Mutação , Animais , Animais Recém-Nascidos , Contagem de Células , Movimento Celular , Epitélio Corneano/patologia , Feminino , Heterozigoto , Imuno-Histoquímica , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Endogâmicos CBA , Camundongos Transgênicos , Microftalmia/metabolismo , Microftalmia/patologia , Microscopia ConfocalRESUMO
The pituitary gland is a primary endocrine organ that controls major physiological processes. Abnormal development or homeostatic disruptions can lead to human disorders such as hypopituitarism or tumors. Multiple signaling pathways, including WNT, BMP, FGF, and SHH regulate pituitary development but the role of the Hippo-YAP1/TAZ cascade is currently unknown. In multiple tissues, the Hippo kinase cascade underlies neoplasias; it influences organ size through the regulation of proliferation and apoptosis, and has roles in determining stem cell potential. We have used a sensitive mRNA in situ hybridization method (RNAscope) to determine the expression patterns of the Hippo pathway components during mouse pituitary development. We have also carried out immunolocalisation studies to determine when YAP1 and TAZ, the transcriptional effectors of the Hippo pathway, are active. We find that YAP1/TAZ are active in the stem/progenitor cell population throughout development and at postnatal stages, consistent with their role in promoting the stem cell state. Our results demonstrate for the first time the collective expression of major components of the Hippo pathway during normal embryonic and postnatal development of the pituitary gland.
RESUMO
BACKGROUND AND OBJECTIVES: Anxiety disorders comprise the most common category of mental illness among US young adults. Art making might be one method to help reduce anxiety, but the few studies investigating this have used only subjective measures of anxiety. DESIGN: This study employed both subjective (self-reported state anxiety from the State-Trait Anxiety Inventory) and objective (heart rate variability) measures to assess whether 30-minute periods of art making reduced anxiety in 47 first-year college students prior to their final examinations. METHODS: Students participated in free-form painting, mandala coloring, clay modeling, and control sessions. RESULTS: Repeated-measures ANOVA with post hoc analysis revealed significantly greater pre- to post-session reductions in anxiety for all three types of art-making sessions than for the control session, as measured objectively. Measured subjectively, only free-form painting yielded a significant decrease in anxiety compared to the control session. CONCLUSIONS: Given the health benefits of anxiety reduction, further study is warranted to determine the duration of art making's anxiety-reducing effect.