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1.
Nat Commun ; 12(1): 5056, 2021 08 20.
Artigo em Inglês | MEDLINE | ID: mdl-34417458

RESUMO

Melanoma cells rely on developmental programs during tumor initiation and progression. Here we show that the embryonic stem cell (ESC) factor Sall4 is re-expressed in the Tyr::NrasQ61K; Cdkn2a-/- melanoma model and that its expression is necessary for primary melanoma formation. Surprisingly, while Sall4 loss prevents tumor formation, it promotes micrometastases to distant organs in this melanoma-prone mouse model. Transcriptional profiling and in vitro assays using human melanoma cells demonstrate that SALL4 loss induces a phenotype switch and the acquisition of an invasive phenotype. We show that SALL4 negatively regulates invasiveness through interaction with the histone deacetylase (HDAC) 2 and direct co-binding to a set of invasiveness genes. Consequently, SALL4 knock down, as well as HDAC inhibition, promote the expression of an invasive signature, while inhibition of histone acetylation partially reverts the invasiveness program induced by SALL4 loss. Thus, SALL4 appears to regulate phenotype switching in melanoma through an HDAC2-mediated mechanism.


Assuntos
Epigênese Genética , Melanoma/genética , Melanoma/patologia , Neoplasias Cutâneas/genética , Neoplasias Cutâneas/patologia , Fator de Células-Tronco/metabolismo , Fatores de Transcrição/metabolismo , Acetilação , Animais , Sequência de Bases , Carcinogênese/genética , Carcinogênese/patologia , Adesão Celular/genética , Linhagem Celular Tumoral , Linhagem da Célula , Proliferação de Células , Proteínas de Ligação a DNA/metabolismo , Perfilação da Expressão Gênica , Regulação Neoplásica da Expressão Gênica , Histona Desacetilase 2/metabolismo , Histonas/metabolismo , Humanos , Melanócitos/metabolismo , Melanócitos/patologia , Camundongos Nus , Camundongos Transgênicos , Invasividade Neoplásica , Micrometástase de Neoplasia , Ligação Proteica , Carga Tumoral
2.
Endocrinology ; 162(2)2021 02 01.
Artigo em Inglês | MEDLINE | ID: mdl-33248443

RESUMO

Prolactin production is controlled by a complex and temporally dynamic network of factors. Despite this tightly coordinated system, pathological hyperprolactinemia is a common endocrine disorder that is often not understood, thereby highlighting the need to expand our molecular understanding of lactotroph cell regulation. MicroRNA-7 (miR-7) is the most highly expressed miRNA family in the pituitary gland and the loss of the miR-7 family member, miR-7a2, is sufficient to reduce prolactin gene expression in mice. Here, we used conditional loss-of-function and gain-of-function mouse models to characterize the function of miR-7a2 in lactotroph cells. We found that pituitary miR-7a2 expression undergoes developmental and sex hormone-dependent regulation. Unexpectedly, the loss of mir-7a2 induces a premature increase in prolactin expression and lactotroph abundance during embryonic development, followed by a gradual loss of prolactin into adulthood. On the other hand, lactotroph development is delayed in mice overexpressing miR-7a2. This regulation of lactotroph function by miR-7a2 involves complementary mechanisms in multiple cell populations. In mouse pituitary and rat prolactinoma cells, miR-7a2 represses its target Raf1, which promotes prolactin gene expression. These findings shed light on the complex regulation of prolactin production and may have implications for the physiological and pathological mechanisms underlying hyperprolactinemia.


Assuntos
Lactotrofos/fisiologia , MicroRNAs/fisiologia , Prolactina/metabolismo , Animais , Linhagem Celular , Estradiol/metabolismo , Feminino , Fertilidade , Lactação , Masculino , Camundongos , Neoplasias Hipofisárias/metabolismo , Prolactinoma/metabolismo , Proteínas Proto-Oncogênicas c-raf/metabolismo , Caracteres Sexuais
3.
Endocrinology ; 161(5)2020 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-32191302

RESUMO

Follicle-stimulating hormone (FSH), an essential regulator of mammalian fertility, is synthesized by pituitary gonadotrope cells in response to activins. In mice, activins signal via SMAD3, SMAD4, and FOXL2 to regulate transcription of the FSHß subunit (Fshb) gene. Gonadotrope-specific deletion of Foxl2, alone or in combination with Smad4, renders mice FSH-deficient. Whether human FSHB expression is similarly regulated is not known. Here, we used a combination of transgenic and conditional knockout mouse strains to assess the roles of activins, FOXL2, and SMAD4 in regulation of the human FSHB gene. First, we cultured pituitaries from mice harboring a human FSHB transgene (hFSHB mice) and measured both murine Fshb and human FSHB messenger ribonucleic acid (mRNA) expression in response to exogenous activins or two antagonists of endogenous activin-like signaling (follistatin-288 and SB431542). Both murine Fshb and human FSHB expression were stimulated by activins and reduced by the inhibitors. Next, we analyzed human FSHB expression in hFSHB mice carrying floxed Foxl2 and Smad4 alleles. Cre-mediated ablation of FOXL2 and SMAD4 strongly reduced basal and activin-stimulated murine Fshb and human FSHB expression in cultured pituitaries. Finally, the hFSHB transgene was previously shown to rescue FSH production and fertility in Fshb knockout mice. However, gonadotrope-specific Foxl2/Smad4 knockout females carrying the hFSHB transgene have significantly reduced murine Fshb and human FSHB pituitary mRNA levels and are hypogonadal. Collectively, these data suggest that similar to Fshb regulation in mice, FOXL2 and SMAD4 play essential roles in human FSHB expression.


Assuntos
Subunidade beta do Hormônio Folículoestimulante/genética , Proteína Forkhead Box L2/genética , Hipófise/metabolismo , Proteína Smad4/genética , Ativinas/farmacologia , Animais , Feminino , Subunidade beta do Hormônio Folículoestimulante/metabolismo , Proteína Forkhead Box L2/metabolismo , Expressão Gênica/efeitos dos fármacos , Humanos , Masculino , Camundongos Knockout , Camundongos Transgênicos , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Proteína Smad4/metabolismo , Técnicas de Cultura de Tecidos
4.
Nat Methods ; 16(9): 870-874, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-31384047

RESUMO

Light-sheet imaging of cleared and expanded samples creates terabyte-sized datasets that consist of many unaligned three-dimensional image tiles, which must be reconstructed before analysis. We developed the BigStitcher software to address this challenge. BigStitcher enables interactive visualization, fast and precise alignment, spatially resolved quality estimation, real-time fusion and deconvolution of dual-illumination, multitile, multiview datasets. The software also compensates for optical effects, thereby improving accuracy and enabling subsequent biological analysis.


Assuntos
Encéfalo/diagnóstico por imagem , Encéfalo/metabolismo , Proteínas de Fluorescência Verde/metabolismo , Processamento de Imagem Assistida por Computador/métodos , Microscopia de Fluorescência/métodos , Software , Animais , Caenorhabditis elegans , Drosophila , Feminino , Imageamento Tridimensional/métodos , Camundongos
5.
Nat Metab ; 1(2): 222-235, 2019 02.
Artigo em Inglês | MEDLINE | ID: mdl-32694784

RESUMO

Heterogeneous populations of hypothalamic neurons orchestrate energy balance via the release of specific signatures of neuropeptides. However, how specific intracellular machinery controls peptidergic identities and function of individual hypothalamic neurons remains largely unknown. The transcription factor T-box 3 (Tbx3) is expressed in hypothalamic neurons sensing and governing energy status, whereas human TBX3 haploinsufficiency has been linked with obesity. Here, we demonstrate that loss of Tbx3 function in hypothalamic neurons causes weight gain and other metabolic disturbances by disrupting both the peptidergic identity and plasticity of Pomc/Cart and Agrp/Npy neurons. These alterations are observed after loss of Tbx3 in both immature hypothalamic neurons and terminally differentiated mouse neurons. We further establish the importance of Tbx3 for body weight regulation in Drosophila melanogaster and show that TBX3 is implicated in the differentiation of human embryonic stem cells into hypothalamic Pomc neurons. Our data indicate that Tbx3 directs the terminal specification of neurons as functional components of the melanocortin system and is required for maintaining their peptidergic identity. In summary, we report the discovery of a key mechanistic process underlying the functional heterogeneity of hypothalamic neurons governing body weight and systemic metabolism.


Assuntos
Hipotálamo/metabolismo , Melanocortinas/metabolismo , Neurônios/metabolismo , Proteínas com Domínio T/metabolismo , Proteína Relacionada com Agouti/genética , Proteína Relacionada com Agouti/metabolismo , Animais , Peso Corporal , Metabolismo Energético , Perfilação da Expressão Gênica , Proteínas de Fluorescência Verde/genética , Hipotálamo/citologia , Camundongos , Camundongos Endogâmicos C57BL , Pró-Opiomelanocortina/genética , RNA Mensageiro/genética , Proteínas com Domínio T/genética
6.
EMBO Rep ; 19(10)2018 10.
Artigo em Inglês | MEDLINE | ID: mdl-30177554

RESUMO

MacroH2A histone variants suppress tumor progression and act as epigenetic barriers to induced pluripotency. How they impart their influence on chromatin plasticity is not well understood. Here, we analyze how the different domains of macroH2A proteins contribute to chromatin structure and dynamics. By solving the crystal structure of the macrodomain of human macroH2A2 at 1.7 Å, we find that its putative binding pocket exhibits marked structural differences compared with the macroH2A1.1 isoform, rendering macroH2A2 unable to bind ADP-ribose. Quantitative binding assays show that this specificity is conserved among vertebrate macroH2A isoforms. We further find that macroH2A histones reduce the transient, PARP1-dependent chromatin relaxation that occurs in living cells upon DNA damage through two distinct mechanisms. First, macroH2A1.1 mediates an isoform-specific effect through its ability to suppress PARP1 activity. Second, the unstructured linker region exerts an additional repressive effect that is common to all macroH2A proteins. In the absence of DNA damage, the macroH2A linker is also sufficient for rescuing heterochromatin architecture in cells deficient for macroH2A.


Assuntos
Cromatina/genética , Epigênese Genética/genética , Histonas/química , Adenosina Difosfato Ribose/química , Adenosina Difosfato Ribose/genética , Cromatina/química , Cristalografia por Raios X , Dano ao DNA/genética , Heterocromatina/química , Heterocromatina/genética , Histonas/genética , Humanos , Poli(ADP-Ribose) Polimerase-1/química , Poli(ADP-Ribose) Polimerase-1/genética , Conformação Proteica , Isoformas de Proteínas/química , Isoformas de Proteínas/genética
7.
Endocrinology ; 159(7): 2641-2655, 2018 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-29800110

RESUMO

The glycoprotein FSH, a product of pituitary gonadotrope cells, regulates ovarian follicle development in females and spermatogenesis in males. FSH is a heterodimer of the common α gonadotropin subunit and the hormone-specific FSHß subunit (a product of the Fshb gene). Using a conditional knockout approach (Cre-lox), we previously demonstrated that Fshb expression in mice depends on the transcription factors forkhead box L2 (FOXL2) and SMAD4. Deletion of Foxl2 or Smad4 alone led to FSH deficiency, female subfertility, and oligozoospermia in males. Simultaneous deletion of the two genes yielded a greater suppression of FSH and female sterility. The Cre-driver used previously was first active during embryonic development. Therefore, it is unclear whether FOXL2 and SMAD4 play important roles in the development or adult function of gonadotropes, or both. To address this question, we developed a tamoxifen-inducible Cre-driver line, which enabled Foxl2 and Smad4 gene deletions in gonadotropes of adult mice. After tamoxifen treatment, females with previously demonstrated fertility exhibited profound reductions in FSH levels, arrested ovarian follicle development, and sterility. FSH levels were comparably reduced in males 1 or 2 months after treatment; however, spermatogenesis was unaffected. These data indicate that (1) FOXL2 and SMAD4 are necessary to maintain FSH synthesis in gonadotrope cells of adult mice, (2) FSH is essential for female reproduction but appears to be unnecessary for the maintenance of spermatogenesis in adult male mice, and (3) the inducible Cre-driver line developed here provides a powerful tool to interrogate gene function in gonadotrope cells of adult mice.


Assuntos
Hormônio Foliculoestimulante/deficiência , Proteína Forkhead Box L2/metabolismo , Gonadotrofos/metabolismo , Oligospermia/metabolismo , Proteína Smad4/metabolismo , Animais , Feminino , Citometria de Fluxo , Hormônio Foliculoestimulante/genética , Hormônio Foliculoestimulante/metabolismo , Proteína Forkhead Box L2/genética , Imuno-Histoquímica , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Oligospermia/genética , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Proteína Smad4/genética
8.
Elife ; 72018 03 26.
Artigo em Inglês | MEDLINE | ID: mdl-29578405

RESUMO

The pituitary is an essential endocrine gland regulating multiple processes. Regeneration of endocrine cells is of therapeutic interest and recent studies are promising, but mechanisms of endocrine cell fate acquisition need to be better characterised. The NOTCH pathway is important during pituitary development. Here, we further characterise its role in the murine pituitary, revealing differential sensitivity within and between lineages. In progenitors, NOTCH activation blocks cell fate acquisition, with time-dependant modulation. In differentiating cells, response to activation is blunted in the POU1F1 lineage, with apparently normal cell fate specification, while POMC cells remain sensitive. Absence of apparent defects in Pou1f1-Cre; Rbpjfl/fl mice further suggests no direct role for NOTCH signalling in POU1F1 cell fate acquisition. In contrast, in the POMC lineage, NICD expression induces a regression towards a progenitor-like state, suggesting that the NOTCH pathway specifically blocks POMC cell differentiation. These results have implications for pituitary development, plasticity and regeneration. Activation of NOTCH signalling in different cell lineages of the embryonic murine pituitary uncovers an unexpected differential sensitivity, and this consequently reveals new aspects of endocrine lineages development and plasticity.


Assuntos
Diferenciação Celular , Linhagem da Célula , Células Endócrinas/fisiologia , Hipófise/fisiologia , Receptores Notch/metabolismo , Animais , Regulação da Expressão Gênica , Camundongos , Transdução de Sinais
9.
Hum Mol Genet ; 24(11): 3092-103, 2015 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-25687138

RESUMO

Foxl2 codes for a forkhead/HNF3 transcription factor essential for follicular maturation and maintenance of ovarian identity. FOXL2 mutations are associated with Blepharophimosis, Ptosis and Epicanthus inversus Syndrome (BPES) characterized by eyelid malformations (types I and II) and premature ovarian insufficiency (type I). We show that Foxl2 is not only expressed by the ovary, but also by other components of the mouse female reproductive tract, including the uterus, the cervix and the oviduct. In the uterus, Foxl2 expression is first observed in the neonatal mesenchyme and, during uterine maturation, persists in the stroma and in the deep inner myometrial layer (IML). In the adult, Foxl2 is expressed in the differentiated stromal layer, but no longer in the myometrium. Conditional deletion of Foxl2 in the postnatal (PN) uterus using Progesterone Receptor-cre (Pgr(cre/+)) mice results in infertility. During PN uterine maturation Pgr(cre/+); Foxl2(flox/flox) mice present a severely reduced thickness of the stroma layer and an hypertrophic, disorganized IML. In adult Pgr(cre/+); Foxl2(flox/flox) mice a supplementary muscular layer is present at the stroma/myometrium border and vascular smooth muscle cells fail to form a coherent layer around uterine arteries. Wnt signalling pathways play a central role in uterine maturation; in Pgr(cre/+); Foxl2(flox/flox) mice, Wnt genes are deregulated suggesting that Foxl2 acts through these signals. In humans, thickening of the IML (also called "junctional zone") is associated with reduced fertility, endometriosis and adenomyosis. Our data suggest that Foxl2 has a crucial role in PN uterine maturation and could help to understand sub-fertility predisposition in women.


Assuntos
Fatores de Transcrição Forkhead/fisiologia , Útero/crescimento & desenvolvimento , Animais , Feminino , Proteína Forkhead Box L2 , Estudos de Associação Genética , Infertilidade Feminina/genética , Infertilidade Feminina/metabolismo , Masculino , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Músculo Liso/patologia , Especificidade de Órgãos , Útero/irrigação sanguínea , Útero/patologia
10.
Hum Mol Genet ; 24(6): 1670-81, 2015 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-25416281

RESUMO

Blepharophimosis, ptosis, epicanthus-inversus syndrome (BPES) is an autosomal dominant genetic disorder characterized by narrow palpebral fissures and eyelid levator muscle defects. BPES is often associated to premature ovarian insufficiency (BPES type I). FOXL2, a member of the forkhead transcription factor family, is the only gene known to be mutated in BPES. Foxl2 is essential for maintenance of ovarian identity, but the developmental origin of the facial malformations of BPES remains, so far, unexplained. In this study, we provide the first detailed account of the developmental processes leading to the craniofacial malformations associated to Foxl2. We show that, during development, Foxl2 is expressed both by Cranial Neural Crest Cells (CNCCs) and by Cranial Mesodermal Cells (CMCs), which give rise to skeletal (CNCCs and CMCs) and muscular (CMCs) components of the head. Using mice in which Foxl2 is selectively inactivated in either CNCCs or CMCs, we reveal that expression of Foxl2 in CNCCs is essential for the development of extraocular muscles. Indeed, inactivation of Foxl2 in CMCs has only minor effects on muscle development, whereas its inactivation in CNCCs provokes a severe hypoplasia of the levator palpabrae superioris and of the superior and inferior oblique muscles. We further show that Foxl2 deletion in either CNCCs or CMCs prevents eyelid closure and induces subtle skeletal developmental defects. Our results provide new insights in the complex developmental origin of human BPES and could help to understand the origin of other ocular anomalies associated to this syndrome.


Assuntos
Blefarofimose/etiologia , Anormalidades Craniofaciais/etiologia , Pálpebras/embriologia , Fatores de Transcrição Forkhead/genética , Músculos Oculomotores/embriologia , Anormalidades da Pele/etiologia , Anormalidades Urogenitais/etiologia , Animais , Pálpebras/anormalidades , Proteína Forkhead Box L2 , Deleção de Genes , Expressão Gênica , Camundongos , Músculos Oculomotores/anormalidades
11.
FASEB J ; 28(8): 3396-410, 2014 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-24739304

RESUMO

Follicle-stimulating hormone (FSH) is an essential regulator of gonadal function and fertility. Loss-of-function mutations in the FSHB/Fshb gene cause hypogonadotropic hypogonadism in humans and mice. Both gonadotropin-releasing hormone (GnRH) and activins, members of the transforming growth factor ß (TGFß) superfamily, stimulate FSH synthesis; yet, their relative roles and mechanisms of action in vivo are unknown. Here, using conditional gene-targeting, we show that the canonical mediator of TGFß superfamily signaling, SMAD4, is absolutely required for normal FSH synthesis in both male and female mice. Moreover, when the Smad4 gene is ablated in combination with its DNA binding cofactor Foxl2 in gonadotrope cells, mice make essentially no FSH and females are sterile. Indeed, the phenotype of these animals is remarkably similar to that of Fshb-knockout mice. Not only do these results establish SMAD4 and FOXL2 as essential master regulators of Fshb transcription in vivo, they also suggest that activins, or related ligands, could play more important roles in FSH synthesis than GnRH.


Assuntos
Fertilidade/fisiologia , Hormônio Foliculoestimulante/biossíntese , Fatores de Transcrição Forkhead/fisiologia , Infertilidade Feminina/fisiopatologia , Infertilidade Masculina/fisiopatologia , Proteína Smad4/fisiologia , Animais , Células Cultivadas , Cruzamentos Genéticos , Feminino , Fertilidade/genética , Hormônio Foliculoestimulante/sangue , Hormônio Foliculoestimulante/deficiência , Proteína Forkhead Box L2 , Fatores de Transcrição Forkhead/deficiência , Gonadotrofos/metabolismo , Hipogonadismo/genética , Hipogonadismo/patologia , Infertilidade Feminina/genética , Infertilidade Feminina/patologia , Infertilidade Masculina/genética , Infertilidade Masculina/patologia , Hormônio Luteinizante/metabolismo , Masculino , Camundongos , Camundongos Knockout , Ovário/patologia , Fenótipo , Maturidade Sexual , Proteína Smad4/deficiência , Contagem de Espermatozoides , Testículo/patologia , Fator de Crescimento Transformador beta/fisiologia
12.
Mol Endocrinol ; 27(3): 407-21, 2013 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-23340250

RESUMO

Impairments in pituitary FSH synthesis or action cause infertility. However, causes of FSH dysregulation are poorly described, in part because of our incomplete understanding of mechanisms controlling FSH synthesis. Previously, we discovered a critical role for forkhead protein L2 (FOXL2) in activin-stimulated FSH ß-subunit (Fshb) transcription in immortalized cells in vitro. Here, we tested the hypothesis that FOXL2 is required for FSH synthesis in vivo. Using a Cre/lox approach, we selectively ablated Foxl2 in murine anterior pituitary gonadotrope cells. Conditional knockout (cKO) mice developed overtly normally but were subfertile in adulthood. Testis size and spermatogenesis were significantly impaired in cKO males. cKO females exhibited reduced ovarian weight and ovulated fewer oocytes in natural estrous cycles compared with controls. In contrast, ovaries of juvenile cKO females showed normal responses to exogenous gonadotropin stimulation. Both male and female cKO mice were FSH deficient, secondary to diminished pituitary Fshb mRNA production. Basal and activin-stimulated Fshb expression was similarly impaired in Foxl2 depleted primary pituitary cultures. Collectively, these data definitively establish FOXL2 as the first identified gonadotrope-restricted transcription factor required for selective FSH synthesis in vivo.


Assuntos
Fertilidade , Subunidade beta do Hormônio Folículoestimulante/biossíntese , Fatores de Transcrição Forkhead/deficiência , Gonadotrofos/metabolismo , Ativinas/farmacologia , Animais , Feminino , Subunidade beta do Hormônio Folículoestimulante/deficiência , Proteína Forkhead Box L2 , Fatores de Transcrição Forkhead/genética , Fatores de Transcrição Forkhead/metabolismo , Deleção de Genes , Regulação da Expressão Gênica/efeitos dos fármacos , Loci Gênicos/genética , Gonadotrofos/efeitos dos fármacos , Gonadotropinas/sangue , Cavalos , Humanos , Masculino , Camundongos , Camundongos Knockout , Tamanho do Órgão/efeitos dos fármacos , Especificidade de Órgãos/efeitos dos fármacos , Folículo Ovariano/efeitos dos fármacos , Folículo Ovariano/fisiologia , Ovulação/efeitos dos fármacos , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Recombinação Genética/genética , Células de Sertoli/citologia , Células de Sertoli/efeitos dos fármacos , Células de Sertoli/metabolismo , Espermatogênese/efeitos dos fármacos , Testículo/citologia , Testículo/efeitos dos fármacos , Testículo/metabolismo
13.
Reproduction ; 142(4): 489-95, 2011 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-21810859

RESUMO

Since the discovery of the conserved forkhead (Fkh) DNA binding domain more than 20 years ago, members of the Fkh or forkhead box (FOX) family of transcription factors have been shown to act as important regulators of numerous developmental and homeostatic processes. The human genome contains 44 Fkh genes, several of which have recently been reported to be essential for female fertility. In this review, we highlight the roles of specific FOX proteins in ovarian folliculogenesis and present our current understanding of their molecular function. In particular, we describe what we have learned from loss-of-function studies using mouse models as well as human genetics and illustrate how different stages of folliculogenesis, both in oocytes and in somatic granulosa and theca cells, are regulated by FOXC1, FOXL2, and FOXO subfamily members.


Assuntos
Fatores de Transcrição Forkhead/fisiologia , Folículo Ovariano/fisiologia , Ovário/fisiologia , Animais , Feminino , Homeostase/fisiologia , Humanos , Camundongos , Modelos Animais , Reprodução/fisiologia
14.
Dev Biol ; 349(1): 65-77, 2011 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-20965161

RESUMO

The sex of an individual results from the paternal transmission of the SRY gene located on the Y chromosome. In turn, SRY initiates Sox9 expression, a transcription factor required for testicular differentiation. Ectopic activation of SOX9 in XX Wt1:Sox9 transgenic mice induces female-to-male sex reversal in adult mice. Here we show that complete sex reversal is preceded by a transient phase of ovotestis differentiation with XX Wt1:Sox9 transgenic gonads containing a testicular central region and one or both ovarian poles indicating that Wt1:Sox9 is not as efficient as Sry to induce male development. In XX Wt1:Sox9(Tg/+) gonads, transgenic Sox9 is expressed earlier than Sox9 in XY gonads and is able to induce the expression of EGFP, knocked into the 3' UTR of Sox9 indicating that SOX9 is involved in the initiation and maintenance of its own expression. However, the delayed onset of expression of endogenous Sox9-EGFP suggests that this activation requires other factors, whose expression depends on SOX9. In the testicular regions of the XX Wt1:Sox9 ovotestes, proliferation of the XX fetal germ cells is hampered and they differentiate as pro-spermatogonia. This indicates that XX germ cells are not competent to respond to proliferative signals released from a testicular environment. In the ovarian regions, despite the continuous mRNA expression of the WT1:Sox9 transgene, the SOX9 protein does not accumulate suggesting that regulation of this gene in ovarian cells involves post-transcriptional mechanisms. Finally, ovarian cells of the XX Wt1:Sox9 ovotestis undergo apoptosis during late embryogenesis leading to complete female-to-male sex reversal of the transgenic mice at birth.


Assuntos
Ovário/embriologia , Ovário/metabolismo , Fatores de Transcrição SOX9/metabolismo , Testículo/embriologia , Testículo/metabolismo , Cromossomo X , Animais , Feminino , Células Germinativas/citologia , Células Germinativas/metabolismo , Masculino , Camundongos , Camundongos Transgênicos , Ovário/citologia , Fatores de Transcrição SOX9/genética , Testículo/citologia , Transcrição Genética , Cromossomo Y
15.
Semin Cell Dev Biol ; 21(8): 831-7, 2010 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-20817112

RESUMO

Chronic kidney disease (CKD) has become a major public health problem worldwide. Therefore, a considerable effort is currently directed to understand the molecular mechanisms of renal degenerative processes. Regardless of their initiating cause, all chronic kidney diseases (CKD) develop at some level organ fibrosis that interferes with kidney function. This is also true for the two most common inherited CKD syndromes, nephronophthitis and polycystic kidney disease, whose primary defects reside within the cilium of kidney epithelial cells. A cohort of elegant recent studies has elicited the role of the primary cilium as a versatile mechanosensory organelle that also might coordinate cross-talk between multiple signaling pathways. In addition, epigenetic mechanisms are now realized to be essential in the maintenance of adult renal architecture. In this review, we will discuss recent advances in our understanding of the signaling systems implicated in kidney homeostasis and repair.


Assuntos
Nefropatias/genética , Nefropatias/patologia , Fibrose , Humanos , Rim/metabolismo , Rim/patologia , Nefropatias/metabolismo , Doenças Renais Císticas/genética , Doenças Renais Císticas/metabolismo , Doenças Renais Císticas/patologia , Insuficiência Renal/metabolismo , Insuficiência Renal/patologia , Transdução de Sinais
16.
Cell ; 139(6): 1130-42, 2009 Dec 11.
Artigo em Inglês | MEDLINE | ID: mdl-20005806

RESUMO

In mammals, the transcription factor SRY, encoded by the Y chromosome, is normally responsible for triggering the indifferent gonads to develop as testes rather than ovaries. However, testis differentiation can occur in its absence. Here we demonstrate in the mouse that a single factor, the forkhead transcriptional regulator FOXL2, is required to prevent transdifferentiation of an adult ovary to a testis. Inducible deletion of Foxl2 in adult ovarian follicles leads to immediate upregulation of testis-specific genes including the critical SRY target gene Sox9. Concordantly, reprogramming of granulosa and theca cell lineages into Sertoli-like and Leydig-like cell lineages occurs with testosterone levels comparable to those of normal XY male littermates. Our results show that maintenance of the ovarian phenotype is an active process throughout life. They might also have important medical implications for the understanding and treatment of some disorders of sexual development in children and premature menopause in women.


Assuntos
Transdiferenciação Celular , Fatores de Transcrição Forkhead/metabolismo , Ovário/metabolismo , Testículo/metabolismo , Animais , Feminino , Proteína Forkhead Box L2 , Fatores de Transcrição Forkhead/genética , Deleção de Genes , Células da Granulosa/citologia , Masculino , Camundongos , Oócitos/metabolismo , Ovário/citologia , Células de Sertoli/citologia , Testículo/citologia
17.
Development ; 136(2): 295-305, 2009 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-19088088

RESUMO

The Olig3 gene encodes a bHLH factor that is expressed in the ventricular zone of the dorsal alar plate of the hindbrain. We found that the Olig3(+) progenitor domain encompassed subdomains that co-expressed Math1, Ngn1, Mash1 and Ptf1a. Olig3(+) cells give rise to neuronal types in the dorsal alar plate that we denote as class A neurons. We used genetic lineage tracing to demonstrate that class A neurons contribute to the nucleus of the solitary tract and to precerebellar nuclei. The fate of class A neurons was not correctly determined in Olig3 mutant mice. As a consequence, the nucleus of the solitary tract did not form, and precerebellar nuclei, such as the inferior olivary nucleus, were absent or small. At the expense of class A neurons, ectopic Lbx1(+) neurons appeared in the alar plate in Olig3 mutant mice. By contrast, electroporation of an Olig3 expression vector in the chick hindbrain suppressed the emergence of Lbx1(+) neurons. Climbing fiber neurons of the inferior olivary nucleus express Foxd3 and require Olig3 as well as Ptf1a for the determination of their fate. We observed that electroporation of Olig3 and Ptf1a expression vectors, but not either alone, induced Foxd3. We therefore propose that Olig3 can cooperate with Ptf1a to determine the fate of climbing fiber neurons of the inferior olivary nucleus.


Assuntos
Fatores de Transcrição Hélice-Alça-Hélice Básicos/metabolismo , Tronco Encefálico/embriologia , Rombencéfalo/embriologia , Animais , Fatores de Transcrição Hélice-Alça-Hélice Básicos/genética , Tronco Encefálico/citologia , Tronco Encefálico/metabolismo , Embrião de Galinha , Eletroporação , Feminino , Camundongos , Camundongos Knockout , Camundongos Mutantes , Células Neuroepiteliais/classificação , Células Neuroepiteliais/citologia , Neurogênese/genética , Neurogênese/fisiologia , Gravidez , Rombencéfalo/citologia , Rombencéfalo/metabolismo , Medula Espinal/citologia , Medula Espinal/embriologia , Medula Espinal/metabolismo , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo
18.
Trends Genet ; 24(7): 361-71, 2008 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-18514358

RESUMO

Although we are rapidly gaining a more complete understanding of the genes required for kidney function, the molecular pathways that actively maintain organ homeostasis are only beginning to emerge. The study of the most common genetic cause of renal failure, polycystic kidney disease, has revealed a surprising role for primary cilia in controlling nuclear gene expression and cell division during development as well as maintenance of kidney architecture. Conditions that disturb kidney integrity seem to be associated with reversal of developmental processes that ultimately lead to kidney fibrosis and end-stage renal disease (ESRD). In this review, we discuss transcriptional regulators and networks that are important in kidney disease, focusing on those that mediate cilia function and drive renal fibrosis.


Assuntos
Homeostase , Nefropatias/genética , Nefropatias/fisiopatologia , Transcrição Genética , Cílios/patologia , Saúde , Humanos , Podócitos/patologia
19.
Endocrinology ; 149(6): 3009-15, 2008 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-18308842

RESUMO

We recently reported that the hypothalamic homeobox domain transcription factor Bsx plays an essential role in the central nervous system control of spontaneous physical activity and the generation of hyperphagic responses. Moreover, we found Bsx to be a master regulator for the hypothalamic expression of key orexigenic neuropeptide Y and agouti gene-related protein. We now hypothesized that Bsx, which is expressed in the dorsomedial and arcuate nucleus (ARC) of the hypothalamus, is regulated by afferent signals in response to peripheral energy balance. Bsx expression was analyzed using in situ hybridization in fed vs. fasted (24 h) and ghrelin vs. leptin-treated rats, as well as in mice deficient for leptin or the ghrelin signaling. Ghrelin administration increased, whereas ghrelin receptor antagonist decreased ARC Bsx expression. Leptin injection attenuated the fasting-induced increase in ARC Bsx levels but had no effect in fed rats. Dorsomedial hypothalamic nucleus Bsx expression was unaffected by pharmacological modifications of leptin or ghrelin signaling. Obese leptin-deficient (ob/ob) mice, but not obese melanocortin 4 receptor-knockout mice, showed higher expression of Bsx, consistent with dependency from afferent leptin rather than increased adiposity per se. Interestingly, exposure to a high-fat diet triggered Bsx expression, consistent with the concept that decreased leptin signaling due to a high-fat diet induced leptin resistance. Our data indicate that ARC Bsx expression is specifically regulated by afferent energy balance signals, including input from leptin and ghrelin. Future studies will be necessary to test if Bsx may be involved in the pathogenesis of leptin resistance.


Assuntos
Ingestão de Alimentos/fisiologia , Atividade Motora/fisiologia , Proteína X Associada a bcl-2/fisiologia , Animais , Metabolismo Energético , Jejum , Grelina/sangue , Insulina/sangue , Leptina/sangue , Masculino , RNA Mensageiro/genética , Ratos , Ratos Sprague-Dawley , Proteína X Associada a bcl-2/genética
20.
J Comp Neurol ; 505(1): 73-91, 2007 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-17729296

RESUMO

To understand the molecular basis of the specification of thalamic nuclei, we analyzed the expression patterns of various transcription factors and defined progenitor cell populations in the embryonic mouse thalamus. We show that the basic helix-loop-helix (bHLH) transcription factor Olig3 is expressed in the entire thalamic ventricular zone and the zona limitans intrathalamica (ZLI). Next, we define two distinct progenitor domains within the thalamus, which we name pTH-R and pTH-C, located caudal to the ZLI. pTH-R is immediately caudal to the ZLI and expresses Nkx2.2, Mash1, and Olig3. pTH-C is caudal to pTH-R and expresses Ngn1, Ngn2, and Olig3. Short-term lineage analysis of Olig3-, Mash1-, Ngn1-, and Ngn2-expressing progenitor cells as well as tracing the Pitx2 cell lineage suggests that pTH-C is the only major source of thalamic nuclei containing neurons that project to the cerebral cortex, whereas pTH-R and ZLI are likely to produce distinct postmitotic populations outside of the cortex-projecting part of the thalamus. To determine if pTH-C is composed of subdomains, we characterized expression of the homeodomain protein Dbx1 and the bHLH protein Olig2. We show that Dbx1 is expressed in caudodorsal-high to rostroventral-low gradient within pTH-C. Analysis of heterozygous Dbx1(nlslacZ) knockin mice demonstrated that Dbx1-expressing progenitors preferentially give rise to caudodorsal thalamic nuclei. Olig2 is expressed in an opposite gradient within pTH-C to that of Dbx1. These results establish the molecular heterogeneity within the progenitor cells of the thalamus, and suggest that such heterogeneity contributes to the specification of thalamic nuclei.


Assuntos
Regulação da Expressão Gênica no Desenvolvimento/fisiologia , Proteínas do Tecido Nervoso/metabolismo , Células-Tronco/fisiologia , Tálamo , Animais , Fatores de Transcrição Hélice-Alça-Hélice Básicos/genética , Fatores de Transcrição Hélice-Alça-Hélice Básicos/metabolismo , Embrião de Mamíferos , Feminino , Proteínas de Fluorescência Verde , Hibridização In Situ/métodos , Camundongos , Camundongos Endogâmicos ICR , Camundongos Transgênicos , Proteínas do Tecido Nervoso/genética , Gravidez , Tálamo/citologia , Tálamo/embriologia , Tálamo/crescimento & desenvolvimento
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