RESUMO
Directed differentiation of pluripotent stem cells into specialized cell types represents an invaluable tool for a wide range of applications. Here, we have exploited single-cell transcriptomic data to develop a stepwise in vitro differentiation system from mouse embryonic stem cells into adrenocortical cells. We show that during development, the adrenal primordium is embedded in an extracellular matrix containing tenascin and fibronectin. Culturing cells on fibronectin during differentiation increased the expression of the steroidogenic marker NR5A1. Furthermore, 3D cultures in the presence of protein kinase A (PKA)-pathway activators led to the formation of aggregates composed of different cell types expressing adrenal progenitor or steroidogenic markers, including the adrenocortical-specific enzyme CYP21A1. Importantly, in-vitro-differentiated cells responded to adrenocorticotropic hormone (ACTH) and angiotensin II with the production of glucocorticoids and mineralocorticoids, respectively, thus confirming the specificity of differentiation toward the adrenal lineage.
Assuntos
Diferenciação Celular , Células-Tronco Pluripotentes , Animais , Camundongos , Células-Tronco Pluripotentes/metabolismo , Células-Tronco Pluripotentes/citologia , Córtex Suprarrenal/citologia , Córtex Suprarrenal/metabolismo , Hormônio Adrenocorticotrópico/metabolismo , Hormônio Adrenocorticotrópico/farmacologia , Fator Esteroidogênico 1/metabolismo , Fator Esteroidogênico 1/genética , Corticosteroides/metabolismo , Células-Tronco Embrionárias Murinas/metabolismo , Células-Tronco Embrionárias Murinas/citologia , Angiotensina II/farmacologia , Células Cultivadas , Proteínas Quinases Dependentes de AMP Cíclico/metabolismo , Fibronectinas/metabolismoRESUMO
CONTEXT: Sexual dimorphism has direct consequences on the incidence and survival of cancer. Early and accurate diagnosis is crucial to improve prognosis. OBJECTIVE: This work aimed to characterized the influence of sex and adrenal asymmetry on the emergence of adrenal tumors. METHODS: We conducted a multicenter, observational study involving 8037 patients with adrenal tumors, including adrenocortical carcinoma (ACC), aldosterone-producing adenoma (APA), cortisol-secreting adrenocortical adenomas (CSAs), non-aldosterone-producing adrenal cortical adenoma (NAPACA), pheochromocytoma (PCC), and neuroblastoma (NB), and investigated tumor lateralization according to sex. Human adrenal tissues (n = 20) were analyzed with a multiomics approach that allows determination of gene expression, catecholamine, and steroid contents in a single sample. In addition, we performed a literature review of computed tomography and magnetic resonance imaging-based studies examining adrenal gland size. RESULTS: ACC (n = 1858); CSA (n = 68), NAPACA (n = 2174), and PCC (n = 1824) were more common in females than in males (female-to-male ratio: 1.1:1-3.8:1), whereas NBs (n = 2320) and APAs (n = 228) were less prevalent in females (0.8:1). ACC, APA, CSA, NAPACA, and NB occurred more frequently in the left than in the right adrenal (left-to-right ratio: 1.1:1-1.8:1), whereas PCC arose more often in the right than in the left adrenal (0.8:1). In both sexes, the left adrenal was larger than the right adrenal; females have smaller adrenals than males. CONCLUSION: Adrenal asymmetry in both sexes may be related to the pathogenesis of adrenal tumors and should be considered during the diagnosis of these tumors.
Assuntos
Neoplasias do Córtex Suprarrenal , Neoplasias das Glândulas Suprarrenais , Adenoma Adrenocortical , Carcinoma Adrenocortical , Feocromocitoma , Feminino , Humanos , Masculino , Corticosteroides , Neoplasias do Córtex Suprarrenal/genética , Glândulas Suprarrenais/diagnóstico por imagem , Glândulas Suprarrenais/metabolismo , Adenoma Adrenocortical/metabolismo , Aldosterona/metabolismo , Feocromocitoma/metabolismo , Caracteres SexuaisRESUMO
Sex determination in mammals depends on the differentiation of the supporting lineage of the gonads into Sertoli or pregranulosa cells that govern testis and ovary development, respectively. Although the Y-linked testis-determining gene Sry has been identified, the ovarian-determining factor remains unknown. In this study, we identified -KTS, a major, alternatively spliced isoform of the Wilms tumor suppressor WT1, as a key determinant of female sex determination. Loss of -KTS variants blocked gonadal differentiation in mice, whereas increased expression, as found in Frasier syndrome, induced precocious differentiation of ovaries independently of their genetic sex. In XY embryos, this antagonized Sry expression, resulting in male-to-female sex reversal. Our results identify -KTS as an ovarian-determining factor and demonstrate that its time of activation is critical in gonadal sex differentiation.
Assuntos
Ovário , Processos de Determinação Sexual , Proteínas WT1 , Animais , Feminino , Masculino , Camundongos , Ovário/crescimento & desenvolvimento , Processos de Determinação Sexual/genética , Proteína da Região Y Determinante do Sexo/genética , Proteína da Região Y Determinante do Sexo/metabolismo , Testículo/crescimento & desenvolvimento , Proteínas WT1/genética , Proteínas WT1/metabolismo , Isoformas de ProteínasRESUMO
Female bias is highly prevalent in conditions such as adrenal cortex hyperplasia and neoplasia, but the reasons behind this phenomenon are poorly understood. In this study, we show that overexpression of the secreted WNT agonist R-spondin 1 (RSPO1) leads to ectopic activation of WNT/ß-catenin signaling and causes sex-specific adrenocortical hyperplasia in mice. Although female adrenals show ectopic proliferation, male adrenals display excessive immune system activation and cortical thinning. Using a combination of genetic manipulations and hormonal treatment, we show that gonadal androgens suppress ectopic proliferation in the adrenal cortex and determine the selective regulation of the WNT-related genes Axin2 and Wnt4. Notably, genetic removal of androgen receptor (AR) from adrenocortical cells restores the mitogenic effect of WNT/ß-catenin signaling. This is the first demonstration that AR activity in the adrenal cortex determines susceptibility to canonical WNT signaling-induced hyperplasia.
Assuntos
Receptores Androgênicos , Via de Sinalização Wnt , Masculino , Camundongos , Feminino , Animais , Receptores Androgênicos/genética , beta Catenina/metabolismo , Hiperplasia , Proteínas Wnt/genéticaRESUMO
Forest canopies are complex and highly diverse environments. Their diversity is affected by pronounced gradients in abiotic and biotic conditions, including variation in leaf chemistry. We hypothesised that branch-localised defence induction and vertical stratification in mature oaks constitute sources of chemical variation that extend across trophic levels. To test this, we combined manipulation of plant defences, predation monitoring, food-choice trials with herbivores and sampling of herbivore assemblages. Both induction and vertical stratification affected branch chemistry, but the effect of induction was stronger. Induction increased predation in the canopy and reduced herbivory in bioassays. The effects of increased predation affected herbivore assemblages by decreasing their abundance, and indirectly, their richness. In turn, we show that there are multiple factors contributing to variation across canopies. Branch-localised induction, variation between tree individuals and predation may be the ones with particularly strong effects on diverse assemblages of insects in temperate forests.
Assuntos
Herbivoria , Árvores , Animais , Florestas , Insetos , Folhas de Planta , Comportamento PredatórioRESUMO
Many adrenocortical diseases are more prevalent in women than in men, but the reasons underlying this sex bias are still unknown. Recent studies involving gonadectomy and sex hormone replacement experiments in mice have shed some light onto the molecular basis of sexual dimorphism in the adrenal cortex. Indeed, it has been shown that gonadal hormones influence many aspects of adrenal physiology, ranging from stem cell-dependent tissue turnover to steroidogenesis and X-zone dynamics. This article reviews current knowledge on adrenal cortex sexual dimorphism and the potential mechanisms underlying sex hormone influence of adrenal homeostasis. Both topics are expected to contribute to personalized and novel therapeutic approaches in the future.
Assuntos
Córtex Suprarrenal/patologia , Doenças das Glândulas Suprarrenais/patologia , Caracteres Sexuais , Animais , Feminino , Hormônios Esteroides Gonadais/metabolismo , Humanos , Masculino , Sexismo , Transdução de SinaisRESUMO
Pheochromocytoma (PCC) and paraganglioma (PGL) are rare neuroendocrine tumors associated with high cardiovascular morbidity and variable risk of malignancy. The current therapy of choice is surgical resection. Nevertheless, PCCs/PGLs are associated with a lifelong risk of tumor persistence or recurrence. A high rate of germline or somatic mutations in numerous genes has been found in these tumors. For some, the tumorigenic processes are initiated during embryogenesis. Such tumors carry gene mutations leading to pseudohypoxic phenotypes and show more immature characteristics than other chromaffin cell tumors; they are also often multifocal or metastatic and occur at an early age, often during childhood. Cancer stem cells (CSCs) are cells with an inherent ability of self-renewal, de-differentiation, and capacity to initiate and maintain malignant tumor growth. Targeting CSCs to inhibit cancer progression has become an attractive anti-cancer therapeutic strategy. Despite progress for this strategy for solid tumors such as neuroblastoma, brain, breast, and colon cancers, no substantial advance has been made employing similar strategies in PCCs/PGLs. In the current review, we discuss findings related to the identification of normal chromaffin stem cells and CSCs, pathways involved in regulating the development of CSCs, and the importance of the stem cell niche in development and maintenance of CSCs in PCCs/PGLs. Additionally, we examine the development and feasibility of novel CSC-targeted therapeutic strategies aimed at eradicating especially recurrent and metastatic tumors.
Assuntos
Neoplasias das Glândulas Suprarrenais/patologia , Células-Tronco Neoplásicas/patologia , Paraganglioma/patologia , Feocromocitoma/patologia , Neoplasias das Glândulas Suprarrenais/etiologia , Animais , Humanos , Paraganglioma/etiologia , Feocromocitoma/etiologiaRESUMO
Developmental cell death plays an important role in the construction of functional neural circuits. In vertebrates, the canonical view proposes a selection of the surviving neurons through stochastic competition for target-derived neurotrophic signals, implying an equal potential for neurons to compete. Here we show an alternative cell fitness selection of neurons that is defined by a specific neuronal heterogeneity code. Proprioceptive sensory neurons that will undergo cell death and those that will survive exhibit different molecular signatures that are regulated by retinoic acid and transcription factors, and are independent of the target and neurotrophins. These molecular features are genetically encoded, representing two distinct subgroups of neurons with contrasted functional maturation states and survival outcome. Thus, in this model, a heterogeneous code of intrinsic cell fitness in neighboring neurons provides differential competitive advantage resulting in the selection of cells with higher capacity to survive and functionally integrate into neural networks.
Assuntos
Modelos Biológicos , Células Receptoras Sensoriais/citologia , Animais , Morte Celular/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Embrião de Galinha , Subunidade alfa 3 de Fator de Ligação ao Core/metabolismo , Camundongos Endogâmicos C57BL , Propriocepção/efeitos dos fármacos , Receptor trkC/metabolismo , Células Receptoras Sensoriais/efeitos dos fármacos , Transdução de Sinais/efeitos dos fármacos , Tretinoína/farmacologiaRESUMO
Glomerular podocytes are terminally differentiated cells, and podocyte loss is a common feature of progressive renal pathologies. In this issue, Romoli et al. focus on podocyte progenitors that were proposed to reside in the Bowman's capsule. They demonstrate that suppression of CXCL12/CXCR4 signaling activates parietal epithelial cells that integrate into glomeruli, express podocyte specific markers, and interdigitate with existing cells. The data may open new therapeutic avenues for the treatment of glomerular diseases.
Assuntos
Podócitos , Cápsula Glomerular , Células Epiteliais , Rim , Glomérulos RenaisRESUMO
The X-linked WTX/AMER1 protein constitutes an important component of the ß-catenin destruction complex that can both enhance and suppress canonical ß-catenin signaling. Somatic mutations in WTX/AMER1 have been found in a proportion of the pediatric kidney cancer Wilms' tumor. By contrast, germline mutations cause the severe sclerosing bone dysplasia osteopathia striata congenita with cranial sclerosis (OSCS), a condition usually associated with fetal or perinatal lethality in male patients. Here we address the developmental and molecular function of WTX by generating two novel mouse alleles. We show that in addition to the previously reported skeletal abnormalities, loss of Wtx causes severe midline fusion defects including cleft palate and ectopic synostosis at the base of the skull. By contrast, deletion of the C-terminal part of the protein results in only mild developmental abnormalities permitting survival beyond birth. Adult analysis, however, revealed skeletal defects including changed skull morphology and an increased whole-body bone density, resembling a subgroup of male patients carrying a milder, survivable phenotype. Molecular analysis in vitro showed that while ß-catenin fails to co-immunoprecipitate with the truncated protein, partial recruitment appears to be achieved in an indirect manner using AXIN/AXIN2 as a molecular bridge. Taken together our analysis provides a novel model for WTX-caused bone diseases and explains on the molecular level how truncation mutations in this gene may retain some of WTX-protein functions. © 2018 American Society for Bone and Mineral Research.
Assuntos
Alelos , Densidade Óssea/genética , Mutação , Osteosclerose , Crânio , Proteínas Supressoras de Tumor , Animais , Modelos Animais de Doenças , Camundongos , Camundongos Mutantes , Osteosclerose/genética , Osteosclerose/metabolismo , Osteosclerose/patologia , Crânio/metabolismo , Crânio/patologia , Proteínas Supressoras de Tumor/genética , Proteínas Supressoras de Tumor/metabolismoRESUMO
WTX/AMER1 is an important developmental regulator, mutations in which have been identified in a proportion of patients suffering from the renal neoplasm Wilms' tumor and in the bone malformation syndrome Osteopathia Striata with Cranial Sclerosis (OSCS). Its cellular functions appear complex and the protein can be found at the membrane, within the cytoplasm and the nucleus. To understand its developmental and cellular function an allelic series for Wtx in the mouse is crucial. Whereas mice carrying a conditional knock out allele for Wtx have been previously reported, a gain-of-function mouse model that would allow studying the molecular, cellular and developmental role of Wtx is still missing. Here we describe the generation of a novel mouse strain that permits the conditional activation of WTX expression. Wtx fused to GFP was introduced downstream a stop cassette flanked by loxP sites into the Rosa26 locus by gene targeting. Ectopic WTX expression is reported after crosses with several Cre transgenic mice in different embryonic tissues. Further, functionality of the fusion protein was demonstrated in the context of a Wtx null allele.
Assuntos
Técnicas de Introdução de Genes/métodos , Proteínas Supressoras de Tumor/genética , Animais , Proteínas de Fluorescência Verde/genética , Proteínas de Fluorescência Verde/metabolismo , Células HEK293 , Humanos , Camundongos , Proteínas Supressoras de Tumor/metabolismoRESUMO
This study evaluated the effect of steam explosion on the chemical composition and biomethane potential of corn stover using temperatures ranging between 140 and 220°C and pretreatment times ranging between 2 and 15min. Biodegradation kinetics during the anaerobic digestion of untreated and corn stover, pretreated at two different intensities, 140°C for 5min and 180°C for 5min, were studied in tandem. Results showed that pretreatment at 160°C for 2min improved the methane yield by 22%. Harsher pretreatment conditions led to lower hemicellulose contents and methane yields, as well as higher lignin contents, which may be due to the formation of pseudo-lignin. The biodegradation kinetics trial demonstrated that steam explosion enhances the degradation of structural carbohydrates and acid insoluble lignin.
Assuntos
Biocombustíveis , Vapor , Explosões , Cinética , Lignina , Zea maysRESUMO
The WT1 (Wilm's tumor suppressor) gene is expressed throughout life in podocytes and is essential for the functional integrity of the glomerular filtration barrier. We have previously shown that CMIP (C-Maf inducing protein) is overproduced in podocyte diseases and alters intracellular signaling. Here we isolated the proximal region of the human CMIP promoter and showed by chromatin immunoprecipitation assays and electrophoretic-mobility shift that Wilm's tumor protein (WT1) bound to 2 WT1 response elements, located at positions -290/-274 and -57/-41 relative to transcription start site. Unlike the human CMIP gene, only one Wt1 response element was identified in the mouse Cmip proximal promoter located at position -217/-206. Luciferase reporter assays indicated that WT1 dose-dependently inhibited the transcriptional induction of the CMIP promoter. Transfection of decoy oligonucleotides mimicking the WT1 response elements prevented the inhibition of WT1 on CMIP promoter activity. Furthermore, WT1 silencing promoted Cmip expression. In line with these findings, the abundance of Cmip was early and significantly increased at the transcript and protein level in podocytes displaying a primary defect in Wt1, including Denys-Drash syndrome and Frasier syndrome. Thus, WT1 is a major repressor of the CMIP gene in physiological situations, while conditional deletion of CMIP in the developing kidney did not affect the development of mature glomeruli.
Assuntos
Proteínas Adaptadoras de Transdução de Sinal/genética , Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Podócitos/metabolismo , Proteínas WT1/metabolismo , Animais , Sequência de Bases , Síndrome de Denys-Drash/metabolismo , Feminino , Síndrome de Frasier/metabolismo , Regulação da Expressão Gênica , Humanos , Rim/embriologia , Masculino , Camundongos , Regiões Promotoras GenéticasRESUMO
Adrenal cortex physiology relies on functional zonation, essential for production of aldosterone by outer zona glomerulosa (ZG) and glucocorticoids by inner zona fasciculata (ZF). The cortex undergoes constant cell renewal, involving recruitment of subcapsular progenitors to ZG fate and subsequent lineage conversion to ZF identity. Here we show that WNT4 is an important driver of WNT pathway activation and subsequent ZG differentiation and demonstrate that PKA activation prevents ZG differentiation through WNT4 repression and WNT pathway inhibition. This suggests that PKA activation in ZF is a key driver of WNT inhibition and lineage conversion. Furthermore, we provide evidence that constitutive PKA activation inhibits, whereas partial inactivation of PKA catalytic activity stimulates ß-catenin-induced tumorigenesis. Together, both lower PKA activity and higher WNT pathway activity lead to poorer prognosis in adrenocortical carcinoma (ACC) patients. These observations suggest that PKA acts as a tumour suppressor in the adrenal cortex, through repression of WNT signalling.
Assuntos
Neoplasias das Glândulas Suprarrenais/etiologia , Proteínas Quinases Dependentes de AMP Cíclico/metabolismo , Via de Sinalização Wnt , Zona Fasciculada/metabolismo , Zona Glomerulosa/metabolismo , Animais , Carcinogênese , Diferenciação Celular , Linhagem Celular Tumoral , Feminino , Humanos , Camundongos , Fosforilação , Zona Fasciculada/citologia , Zona Glomerulosa/citologia , beta Catenina/metabolismoRESUMO
Identifying targets of transcriptional regulators such as the Wilms' tumor-suppressor protein (WT1) is an integral part of understanding the mechanisms governing the spatial and temporal activation of different genes. A commonly used strategy for studying transcription factors involves performing chromatin immunoprecipitation (ChIP) for the protein of interest with an appropriate antibody in crosslinked cells. Following ChIP, the enriched DNA is sequenced using next-generation sequencing (NGS) technologies and the transcription factor target sites are identified via bioinformatics analysis. Here we provide a detailed protocol for performing a successful ChIP-Seq experiment for WT1. We have optimized and simplified the several steps necessary for the immunoprecipitation of WT1's target-binding sites. We also suggest several strategies for validating the experiment and provide brief guidelines on how to analyze the large amounts of data generated from high-throughout sequencing. This method can be adapted for a variety of different tissues and/or cell types to help understand the role of WT1 in regulating gene expression.
Assuntos
Imunoprecipitação da Cromatina/métodos , DNA/metabolismo , Análise de Sequência de DNA/métodos , Proteínas WT1/metabolismo , Sítios de Ligação , Biologia Computacional/métodos , DNA/química , Regulação da Expressão Gênica , Sequenciamento de Nucleotídeos em Larga Escala , Humanos , Software , Proteínas WT1/químicaRESUMO
Liver zonation, the spatial separation of different metabolic pathways along the liver sinusoids, is fundamental for proper functioning of this organ, and its disruption can lead to the development of metabolic disorders such as hyperammonemia. Metabolic zonation involves the induction of ß-catenin signaling around the central veins, but how this patterned activity is established and maintained is unclear. Here, we show that the signaling molecule Rspondin3 is specifically expressed within the endothelial compartment of the central vein. Conditional deletion of Rspo3 in mice disrupts activation of central fate, demonstrating its crucial role in determining and maintaining ß-catenin-dependent zonation. Moreover, ectopic expression of Rspo1, a close family member of Rspo3, induces the expression of pericentral markers, demonstrating Rspondins to be sufficient to imprint a more central fate. Thus, Rspo3 is a key angiocrine factor that controls metabolic zonation of liver hepatocytes.
Assuntos
Trombospondinas/metabolismo , Animais , Proteína Axina/genética , Proteína Axina/metabolismo , Linhagem Celular , Regulação para Baixo/efeitos dos fármacos , Células Endoteliais/citologia , Células Endoteliais/metabolismo , Feminino , Hibridização in Situ Fluorescente , Camundongos , Camundongos Knockout , Receptores Acoplados a Proteínas G/genética , Receptores Acoplados a Proteínas G/metabolismo , Tamoxifeno/farmacologia , Trombospondinas/genética , Proteínas Wnt/genética , Proteínas Wnt/metabolismo , Via de Sinalização Wnt/efeitos dos fármacos , Proteína Wnt2/genética , Proteína Wnt2/metabolismo , beta Catenina/metabolismoRESUMO
After acute kidney injury (AKI), surviving cells within the nephron proliferate and repair. We identify Sox9 as an acute epithelial stress response in renal regeneration. Translational profiling after AKI revealed a rapid upregulation of Sox9 within proximal tubule (PT) cells, the nephron cell type most vulnerable to AKI. Descendants of Sox9(+) cells generate the bulk of the nephron during development and regenerate functional PT epithelium after AKI-induced reactivation of Sox9 after renal injury. After restoration of renal function post-AKI, persistent Sox9 expression highlights regions of unresolved damage within injured nephrons. Inactivation of Sox9 in PT cells pre-injury indicates that Sox9 is required for the normal course of post-AKI recovery. These findings link Sox9 to cell intrinsic mechanisms regulating development and repair of the mammalian nephron.
Assuntos
Injúria Renal Aguda/metabolismo , Reepitelização , Fatores de Transcrição SOX9/metabolismo , Ativação Transcricional , Animais , Linhagem da Célula , Células Epiteliais/citologia , Células Epiteliais/metabolismo , Células Epiteliais/fisiologia , Camundongos , Néfrons/citologia , Néfrons/metabolismo , Fatores de Transcrição SOX9/genética , Regulação para CimaRESUMO
The Wilms' tumor suppressor WT1 is a key regulator of podocyte function that is mutated in Denys-Drash and Frasier syndromes. Here we have used an integrative approach employing ChIP, exon array, and genetic analyses in mice to address general and isoform-specific functions of WT1 in podocyte differentiation. Analysis of ChIP-Seq data showed that almost half of the podocyte-specific genes are direct targets of WT1. Bioinformatic analysis further identified coactivator FOXC1-binding sites in proximity to WT1-bound regions, thus supporting coordinated action of these transcription factors in regulating podocyte-specific genes. Transcriptional profiling of mice lacking the WT1 alternative splice isoform (+KTS) had a more restrictive set of genes whose expression depends on these alternatively spliced isoforms. One of these genes encodes the membrane-associated guanylate kinase MAGI2, a protein that localizes to the base of the slit diaphragm. Using functional analysis in mice, we further show that MAGI2α is essential for proper localization of nephrin and the assembly of the slit diaphragm complex. Finally, a dramatic reduction of MAGI2 was found in an LPS mouse model of glomerular injury and in genetic cases of human disease. Thus, our study highlights the central role of WT1 in podocyte differentiation, identifies that WT1 has a central role in podocyte differentiation, and identifies MAGI2α as the crucial isoform in slit diaphragm assembly, suggesting a causative role of this gene in the etiology of glomerular disorders.
Assuntos
Proteínas Adaptadoras de Transdução de Sinal/genética , Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Diferenciação Celular/genética , Guanilato Quinases/genética , Guanilato Quinases/metabolismo , Podócitos/fisiologia , Proteínas Repressoras/genética , Transcrição Gênica , Processamento Alternativo , Animais , Sítios de Ligação , Regulação para Baixo/efeitos dos fármacos , Éxons , Feminino , Fatores de Transcrição Forkhead/genética , Glomerulonefrite Membranoproliferativa/metabolismo , Glomerulosclerose Segmentar e Focal/metabolismo , Humanos , Lipopolissacarídeos/farmacologia , Proteínas de Membrana/metabolismo , Camundongos , Mutação , Análise de Sequência com Séries de Oligonucleotídeos , Podócitos/patologia , Regiões Promotoras Genéticas , Isoformas de Proteínas/genética , Proteínas Repressoras/metabolismo , Proteínas WT1RESUMO
Adrenal and gonads are the main steroidogenic organs and are central to regulate body homeostasis in the vertebrate organism. Although adrenals and gonads are physically separated in the adult organism, both organs share a common developmental origin, the adrenogonadal primordium. One of the key genes involved in the development of both organs is the Wilms' tumor suppressor WT1, which encodes a zinc finger protein that has fascinated the scientific community for more than two decades. This review will provide an overview of the processes leading to the development of these unique organs with a particular focus on the multiple functions WT1 serves during adrenogonadal development. In addition, we will highlight some recent findings and open questions on how maintenance of steroidogenic organs is achieved in the adult organism.
Assuntos
Homeostase , Organogênese , Esteroides/biossíntese , Proteínas WT1/metabolismo , Animais , Gônadas/metabolismo , Humanos , Relação Estrutura-Atividade , Proteínas WT1/químicaRESUMO
Kidney organogenesis requires the tight control of proliferation, differentiation and apoptosis of renal progenitor cells. How the balance between these cellular decisions is achieved remains elusive. The Wilms' tumour suppressor Wt1 is required for progenitor survival, but the molecular cause for renal agenesis in mutants is poorly understood. Here we demonstrate that lack of Wt1 abolishes fibroblast growth factor (FGF) and induces BMP/pSMAD signalling within the metanephric mesenchyme. Addition of recombinant FGFs or inhibition of pSMAD signalling rescues progenitor cell apoptosis induced by the loss of Wt1. We further show that recombinant BMP4, but not BMP7, induces an apoptotic response within the early kidney that can be suppressed by simultaneous addition of FGFs. These data reveal a hitherto unknown sensitivity of early renal progenitors to pSMAD signalling, establishes FGF and pSMAD signalling as antagonistic forces in early kidney development and places WT1 as a key regulator of pro-survival FGF signalling pathway genes.