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1.
Dev Biol ; 479: 11-22, 2021 11.
Artigo em Inglês | MEDLINE | ID: mdl-34310924

RESUMO

Platelet derived growth factor beta and its receptor, Pdgfrb, play essential roles in the development of vascular mural cells, including pericytes and vascular smooth muscle cells. To determine if this role was conserved in zebrafish, we analyzed pdgfb and pdgfrb mutant lines. Similar to mouse, pdgfb and pdgfrb mutant zebrafish lack brain pericytes and exhibit anatomically selective loss of vascular smooth muscle coverage. Despite these defects, pdgfrb mutant zebrafish did not otherwise exhibit circulatory defects at larval stages. However, beginning at juvenile stages, we observed severe cranial hemorrhage and vessel dilation associated with loss of pericytes and vascular smooth muscle cells in pdgfrb mutants. Similar to mouse, pdgfrb mutant zebrafish also displayed structural defects in the glomerulus, but normal development of hepatic stellate cells. We also noted defective mural cell investment on coronary vessels with concomitant defects in their development. Together, our studies support a conserved requirement for Pdgfrb signaling in mural cells. In addition, these zebrafish mutants provide an important model for definitive investigation of mural cells during early embryonic stages without confounding secondary effects from circulatory defects.


Assuntos
Músculo Liso Vascular/metabolismo , Pericitos/metabolismo , Receptor beta de Fator de Crescimento Derivado de Plaquetas/metabolismo , Animais , Diferenciação Celular , Vasos Coronários/metabolismo , Desenvolvimento Embrionário , Músculo Liso Vascular/embriologia , Miócitos de Músculo Liso/metabolismo , Proteínas Proto-Oncogênicas c-sis/metabolismo , Proteínas Proto-Oncogênicas c-sis/fisiologia , Receptor beta de Fator de Crescimento Derivado de Plaquetas/genética , Transdução de Sinais/genética , Peixe-Zebra/embriologia , Proteínas de Peixe-Zebra/metabolismo
3.
Nat Med ; 27(4): 640-646, 2021 04.
Artigo em Inglês | MEDLINE | ID: mdl-33859435

RESUMO

Apart from well-defined factors in neuronal cells1, only a few reports consider that the variability of sporadic amyotrophic lateral sclerosis (ALS) progression can depend on less-defined contributions from glia2,3 and blood vessels4. In this study we use an expression-weighted cell-type enrichment method to infer cell activity in spinal cord samples from patients with sporadic ALS and mouse models of this disease. Here we report that patients with sporadic ALS present cell activity patterns consistent with two mouse models in which enrichments of vascular cell genes preceded microglial response. Notably, during the presymptomatic stage, perivascular fibroblast cells showed the strongest gene enrichments, and their marker proteins SPP1 and COL6A1 accumulated in enlarged perivascular spaces in patients with sporadic ALS. Moreover, in plasma of 574 patients with ALS from four independent cohorts, increased levels of SPP1 at disease diagnosis repeatedly predicted shorter survival with stronger effect than the established risk factors of bulbar onset or neurofilament levels in cerebrospinal fluid. We propose that the activity of the recently discovered perivascular fibroblast can predict survival of patients with ALS and provide a new conceptual framework to re-evaluate definitions of ALS etiology.


Assuntos
Esclerose Lateral Amiotrófica/patologia , Vasos Sanguíneos/patologia , Fibroblastos/patologia , Esclerose Lateral Amiotrófica/sangue , Esclerose Lateral Amiotrófica/genética , Esclerose Lateral Amiotrófica/fisiopatologia , Animais , Biomarcadores/metabolismo , Colágeno Tipo VI/genética , Colágeno Tipo VI/metabolismo , Proteínas de Ligação a DNA/metabolismo , Progressão da Doença , Marcadores Genéticos , Humanos , Camundongos Transgênicos , Osteopontina/sangue , Prognóstico , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Medula Espinal/patologia , Medula Espinal/ultraestrutura , Superóxido Dismutase/genética , Transcrição Gênica , Remodelação Vascular
4.
Sci Rep ; 10(1): 20037, 2020 11 18.
Artigo em Inglês | MEDLINE | ID: mdl-33208756

RESUMO

Podocytes are critical for the maintenance of kidney ultrafiltration barrier and play a key role in the progression of glomerular diseases. Although mediator complex proteins have been shown to be important for many physiological and pathological processes, their role in kidney tissue has not been studied. In this study, we identified a mediator complex protein 22 (Med22) as a renal podocyte cell-enriched molecule. Podocyte-specific Med22 knockout mouse showed that Med22 was not needed for normal podocyte maturation. However, it was critical for the maintenance of podocyte health as the mice developed progressive glomerular disease and died due to renal failure. Detailed morphological analyses showed that Med22-deficiency in podocytes resulted in intracellular vacuole formation followed by podocyte loss. Moreover, Med22-deficiency in younger mice promoted the progression of glomerular disease, suggesting Med22-mediated processes may have a role in the development of glomerulopathies. This study shows for the first time that mediator complex has a critical role in kidney physiology.


Assuntos
Nefropatias/mortalidade , Glomérulos Renais/patologia , Complexo Mediador/antagonistas & inibidores , Mortalidade Prematura/tendências , Podócitos/patologia , Vacúolos/patologia , Adulto , Animais , Humanos , Nefropatias/etiologia , Nefropatias/patologia , Glomérulos Renais/metabolismo , Complexo Mediador/genética , Complexo Mediador/metabolismo , Camundongos , Camundongos Knockout , Podócitos/metabolismo , Vacúolos/metabolismo
5.
Sci Rep ; 9(1): 8888, 2019 06 20.
Artigo em Inglês | MEDLINE | ID: mdl-31221975

RESUMO

Podocytes have an important role in the pathogenesis of diabetic nephropathy (DN). Podocyte foot process effacement, mediated largely by the actin-based cytoskeleton of foot processes, is commonly detected in DN and is believed to be a key pathogenic event in the development of proteinuria. In this study, we identified coronin 2b (Coro2b), a member of known actin-regulating proteins, the coronins, as a highly podocyte-enriched molecule located at the cytoplasmic side of the apical plasma membrane. Studies in human renal biopsies show that glomerular Coro2b expression is significantly down-regulated in patients with DN. Studies in knockout mice indicate that Coro2b is not required for the development or maintenance of the glomerular filtration barrier. Moreover, inactivation of Coro2b specifically in podocytes does not affect the outcome of nephropathy in a streptozotocin-induced diabetes model. However, Coro2b seems to modulate the reorganization of foot processes under pathological conditions as Coro2b knockout podocytes are partially protected from protamine sulfate perfusion-induced foot process effacement. Taken together, our study suggests a role for Coro2b in the pathogenesis of glomerulopathies. Further studies regarding the involvement of Coro2b in podocyte health and diseases are warranted.


Assuntos
Pé Diabético/metabolismo , Nefropatias Diabéticas/metabolismo , Regulação para Baixo , Proteínas dos Microfilamentos/metabolismo , Podócitos/metabolismo , Protaminas/metabolismo , Humanos
6.
Cell Metab ; 25(3): 713-726, 2017 03 07.
Artigo em Inglês | MEDLINE | ID: mdl-28190774

RESUMO

Diabetic kidney disease (DKD) is the most common cause of severe renal disease, and few treatment options are available today that prevent the progressive loss of renal function. DKD is characterized by altered glomerular filtration and proteinuria. A common observation in DKD is the presence of renal steatosis, but the mechanism(s) underlying this observation and to what extent they contribute to disease progression are unknown. Vascular endothelial growth factor B (VEGF-B) controls muscle lipid accumulation through regulation of endothelial fatty acid transport. Here, we demonstrate in experimental mouse models of DKD that renal VEGF-B expression correlates with the severity of disease. Inhibiting VEGF-B signaling in DKD mouse models reduces renal lipotoxicity, re-sensitizes podocytes to insulin signaling, inhibits the development of DKD-associated pathologies, and prevents renal dysfunction. Further, we show that elevated VEGF-B levels are found in patients with DKD, suggesting that VEGF-B antagonism represents a novel approach to treat DKD.


Assuntos
Nefropatias Diabéticas/metabolismo , Nefropatias Diabéticas/prevenção & controle , Rim/patologia , Lipídeos/toxicidade , Transdução de Sinais , Fator B de Crescimento do Endotélio Vascular/metabolismo , Adulto , Idoso , Albuminúria/complicações , Albuminúria/metabolismo , Albuminúria/patologia , Animais , Anticorpos Neutralizantes/administração & dosagem , Anticorpos Neutralizantes/farmacologia , Diabetes Mellitus Experimental/complicações , Diabetes Mellitus Experimental/metabolismo , Diabetes Mellitus Experimental/patologia , Diabetes Mellitus Tipo 1/complicações , Diabetes Mellitus Tipo 1/metabolismo , Diabetes Mellitus Tipo 1/patologia , Diabetes Mellitus Tipo 2/complicações , Diabetes Mellitus Tipo 2/metabolismo , Diabetes Mellitus Tipo 2/patologia , Nefropatias Diabéticas/patologia , Modelos Animais de Doenças , Progressão da Doença , Dislipidemias/complicações , Dislipidemias/metabolismo , Dislipidemias/patologia , Proteínas de Transporte de Ácido Graxo/metabolismo , Feminino , Deleção de Genes , Humanos , Insulina/farmacologia , Rim/efeitos dos fármacos , Rim/metabolismo , Rim/fisiopatologia , Masculino , Camundongos Endogâmicos C57BL , Pessoa de Meia-Idade , Podócitos/efeitos dos fármacos , Podócitos/metabolismo , Podócitos/patologia , Transdução de Sinais/efeitos dos fármacos , Regulação para Cima/efeitos dos fármacos , Adulto Jovem
7.
Am J Physiol Renal Physiol ; 309(11): F955-66, 2015 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-26377798

RESUMO

Podocytes are highly specialized epithelial cells located at the outer aspects of the glomerular capillary tuft and critical components of the kidney filtration barrier. To maintain their unique features, podocytes express a number of proteins that are only sparsely found elsewhere in the body. In this study, we have identified four (Tmem234, Znf185, Lrrc49, and Slfn5) new highly podocyte-enriched proteins. The proteins are strongly expressed by podocytes, while other parts of the kidney show only weak or no expression. Tmem234, Slfn5, and Lrrc49 are located in foot processes, whereas Znf185 is found in both foot and major processes. Expressional studies in developing kidneys show that these proteins are first expressed at the capillary stage glomerulus, the same stage when the formation of major and foot processes begins. We identified zebrafish orthologs for Tmem234 and Znf185 genes and knocked down their expression using morpholino technology. Studies in zebrafish larvae indicate that Tmem234 is essential for the organization and functional integrity of the pronephric glomerulus filtration barrier, as inactivation of Tmem234 expression results in foot process effacement and proteinuria. In summary, we have identified four novel highly podocyte-enriched proteins and show that one of them, Tmem234, is essential for the normal filtration barrier in the zebrafish pronephric glomerulus. Identification of new molecular components of the kidney filtration barrier opens up possibilities to study their role in glomerulus biology and diseases.


Assuntos
Técnicas de Silenciamento de Genes , Proteínas de Membrana/metabolismo , Podócitos/metabolismo , Proteinúria/metabolismo , Proteínas de Peixe-Zebra/metabolismo , Peixe-Zebra/metabolismo , Sequência de Aminoácidos , Animais , Proteínas de Ciclo Celular/genética , Proteínas de Ciclo Celular/metabolismo , Proteínas do Citoesqueleto/genética , Proteínas do Citoesqueleto/metabolismo , Regulação da Expressão Gênica no Desenvolvimento , Genótipo , Taxa de Filtração Glomerular , Humanos , Proteínas com Domínio LIM/genética , Proteínas com Domínio LIM/metabolismo , Proteínas de Membrana/genética , Camundongos , Dados de Sequência Molecular , Morfolinos/genética , Morfolinos/metabolismo , Fenótipo , Proteinúria/genética , Proteinúria/fisiopatologia , Peixe-Zebra/embriologia , Peixe-Zebra/genética , Proteínas de Peixe-Zebra/genética
8.
Am J Hum Genet ; 96(1): 153-61, 2015 Jan 08.
Artigo em Inglês | MEDLINE | ID: mdl-25557779

RESUMO

Nephrotic syndrome (NS), the association of gross proteinuria, hypoalbuminaemia, edema, and hyperlipidemia, can be clinically divided into steroid-sensitive (SSNS) and steroid-resistant (SRNS) forms. SRNS regularly progresses to end-stage renal failure. By homozygosity mapping and whole exome sequencing, we here identify recessive mutations in Crumbs homolog 2 (CRB2) in four different families affected by SRNS. Previously, we established a requirement for zebrafish crb2b, a conserved regulator of epithelial polarity, in podocyte morphogenesis. By characterization of a loss-of-function mutation in zebrafish crb2b, we now show that zebrafish crb2b is required for podocyte foot process arborization, slit diaphragm formation, and proper nephrin trafficking. Furthermore, by complementation experiments in zebrafish, we demonstrate that CRB2 mutations result in loss of function and therefore constitute causative mutations leading to NS in humans. These results implicate defects in podocyte apico-basal polarity in the pathogenesis of NS.


Assuntos
Proteínas de Transporte/genética , Proteínas de Membrana/genética , Síndrome Nefrótica/genética , Sequência de Aminoácidos , Animais , Proteínas de Transporte/metabolismo , Criança , Pré-Escolar , Mapeamento Cromossômico , Exoma , Genes Recessivos , Homozigoto , Humanos , Lactente , Falência Renal Crônica/etiologia , Falência Renal Crônica/genética , Proteínas de Membrana/metabolismo , Dados de Sequência Molecular , Mutação , Síndrome Nefrótica/complicações , Podócitos , Ratos , Peixe-Zebra/genética
9.
J Am Soc Nephrol ; 25(12): 2764-77, 2014 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-24854274

RESUMO

Podocin is a key protein of the kidney podocyte slit diaphragm protein complex, an important part of the glomerular filtration barrier. Mutations in the human podocin gene NPHS2 cause familial or sporadic forms of renal disease owing to the disruption of filtration barrier integrity. The exclusive expression of NPHS2 in podocytes reflects its unique function and raises interesting questions about its transcriptional regulation. Here, we further define a 2.5-kb zebrafish nphs2 promoter fragment previously described and identify a 49-bp podocyte-specific transcriptional enhancer using Tol2-mediated G0 transgenesis in zebrafish. Within this enhancer, we identified a cis-acting element composed of two adjacent DNA-binding sites (FLAT-E and forkhead) bound by transcription factors Lmx1b and FoxC. In zebrafish, double knockdown of Lmx1b and FoxC orthologs using morpholino doses that caused no or minimal phenotypic changes upon individual knockdown completely disrupted podocyte development in 40% of injected embryos. Co-overexpression of the two genes potently induced endogenous nphs2 expression in zebrafish podocytes. We found that the NPHS2 promoter also contains a cis-acting Lmx1b-FoxC motif that binds LMX1B and FoxC2. Furthermore, a genome-wide search identified several genes that carry the Lmx1b-FoxC motif in their promoter regions. Among these candidates, motif-driven podocyte enhancer activity of CCNC and MEIS2 was functionally analyzed in vivo. Our results show that podocyte expression of some genes is combinatorially regulated by two transcription factors interacting synergistically with a common enhancer. This finding provides insights into transcriptional mechanisms required for normal and pathologic podocyte functions.


Assuntos
Fatores de Transcrição Forkhead/metabolismo , Regulação da Expressão Gênica , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Proteínas de Membrana/metabolismo , Podócitos/metabolismo , Fatores de Transcrição/metabolismo , Proteínas de Peixe-Zebra/metabolismo , Motivos de Aminoácidos , Animais , Animais Geneticamente Modificados , Sítios de Ligação , Elementos Facilitadores Genéticos , Células HEK293 , Humanos , Proteínas com Homeodomínio LIM/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Microscopia Confocal , Mutagênese , Fenótipo , Podócitos/citologia , Regiões Promotoras Genéticas , Transcrição Gênica , Peixe-Zebra
10.
Dev Cell ; 23(3): 587-99, 2012 Sep 11.
Artigo em Inglês | MEDLINE | ID: mdl-22975327

RESUMO

Angiogenesis, the process by which new blood vessels arise from preexisting ones, is critical for embryonic development and is an integral part of many disease processes. Recent studies have provided detailed information on how angiogenic sprouts initiate, elongate, and branch, but less is known about how these processes cease. Here, we show that S1PR1, a receptor for the blood-borne bioactive lipid sphingosine-1-phosphate (S1P), is critical for inhibition of angiogenesis and acquisition of vascular stability. Loss of S1PR1 leads to increased endothelial cell sprouting and the formation of ectopic vessel branches. Conversely, S1PR1 signaling inhibits angiogenic sprouting and enhances cell-to-cell adhesion. This correlates with inhibition of vascular endothelial growth factor-A (VEGF-A)-induced signaling and stabilization of vascular endothelial (VE)-cadherin localization at endothelial junctions. Our data suggest that S1PR1 signaling acts as a vascular-intrinsic stabilization mechanism, protecting developing blood vessels against aberrant angiogenic responses.


Assuntos
Antígenos CD/metabolismo , Caderinas/metabolismo , Neovascularização Fisiológica , Receptores de Lisoesfingolipídeo/metabolismo , Receptor 2 de Fatores de Crescimento do Endotélio Vascular/metabolismo , Animais , Células Cultivadas , Células Endoteliais/metabolismo , Humanos , Camundongos , Camundongos Knockout , Camundongos Transgênicos , Receptores de Lisoesfingolipídeo/deficiência , Receptores de Esfingosina-1-Fosfato , Peixe-Zebra
11.
J Am Soc Nephrol ; 22(11): 2037-46, 2011 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-21949092

RESUMO

Unbiased transcriptome profiling and functional genomics approaches identified glucocorticoid-induced transcript 1 (GLCCI1) as being a transcript highly specific for the glomerulus, but its role in glomerular development and disease is unknown. Here, we report that mouse glomeruli express far greater amounts of Glcci1 protein compared with the rest of the kidney. RT-PCR and Western blotting demonstrated that mouse glomerular Glcci1 is approximately 60 kD and localizes to the cytoplasm of podocytes in mature glomeruli. In the fetal kidney, intense Glcci1 expression occurs at the capillary-loop stage of glomerular development. Using gene knockdown in zebrafish with morpholinos, morphants lacking Glcci1 function had collapsed glomeruli with foot-process effacement. Permeability studies of the glomerular filtration barrier in these zebrafish morphants demonstrated a disruption of the selective glomerular permeability filter. Taken together, these data suggest that Glcci1 promotes the normal development and maintenance of podocyte structure and function.


Assuntos
Glomérulos Renais/fisiopatologia , Podócitos/fisiologia , Pronefro/fisiopatologia , Proteinúria/metabolismo , Proteinúria/fisiopatologia , Receptores de Glucocorticoides/deficiência , Animais , Citoplasma/metabolismo , Dexametasona/farmacologia , Modelos Animais de Doenças , Regulação da Expressão Gênica no Desenvolvimento/efeitos dos fármacos , Regulação da Expressão Gênica no Desenvolvimento/fisiologia , Glucocorticoides/farmacologia , Glomérulos Renais/anormalidades , Masculino , Camundongos , Camundongos Endogâmicos ICR , Oligonucleotídeos Antissenso/farmacologia , Pronefro/anormalidades , Proteinúria/patologia , Coelhos , Receptores de Glucocorticoides/genética , Peixe-Zebra , Proteínas de Peixe-Zebra
12.
J Am Soc Nephrol ; 22(6): 1019-23, 2011 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-21566056

RESUMO

Podocytes do not remain fully differentiated when cultured, and they are difficult to image in vivo, making the study of podocyte biology challenging. Zebrafish embryos are transparent and develop a single, midline, pronephric glomerulus accessible for imaging and systematic functional analysis. Here, we describe a transgenic zebrafish line that expresses green fluorescence protein (GFP) from the zebrafish podocin promoter. The line recapitulates the endogenous pronephric podocin expression pattern, showing GFP expression exclusively in podocytes starting 2 days postfertilization. Using the podocyte GFP signal as a guide for dissection, we examined the pronephric glomerulus by scanning electron microscopy; the surface ultrastructure exhibited fine, interdigitating podocyte foot processes surrounding glomerular capillaries. To determine whether the GFP signal could serve as a direct readout of developmental abnormalities or injury to the glomerulus, we knocked down the podocyte-associated protein crb2b; this led to a loss of GFP signal. Thus, podocin-GFP zebrafish provide a model for ultrastructural studies and in vivo visualization and functional analysis of glomerular podocytes. This model should also be useful for high-throughput genetic or chemical analysis of glomerular development and function.


Assuntos
Proteínas de Fluorescência Verde/metabolismo , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Proteínas de Membrana/metabolismo , Podócitos/citologia , Podócitos/metabolismo , Animais , Animais Geneticamente Modificados , Proteínas de Fluorescência Verde/genética , Peptídeos e Proteínas de Sinalização Intracelular/genética , Glomérulos Renais/citologia , Glomérulos Renais/metabolismo , Glomérulos Renais/ultraestrutura , Proteínas de Membrana/genética , Microscopia Eletrônica de Varredura , Modelos Animais , Podócitos/ultraestrutura , Peixe-Zebra , Proteínas de Peixe-Zebra/genética , Proteínas de Peixe-Zebra/metabolismo
13.
Curr Opin Nephrol Hypertens ; 20(4): 416-24, 2011 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-21519251

RESUMO

PURPOSE OF REVIEW: The zebrafish pronephros provides an informative vertebrate model system for studying renal development and function as well as a rapid screening tool for identification of genes important to the physiology and pathophysiology of the vertebrate kidney. To this end, the zebrafish pronephros is continuously being characterized and its relevance for the study of human diseases validated. This review summarizes recent advances in our current knowledge of the zebrafish pronephros as a valuable model system relevant to the study of human kidney biology and nephropathology. RECENT FINDINGS: Recent findings argue for conserved renal gene structure and function in the zebrafish pronephros and also elucidate the role of genes in kidney biology that were not possible to discern in other vertebrate model systems due to early lethality. SUMMARY: Abnormalities in podocyte gene function, renal ion channels and transporters, and renal epithelial primary cilia genes lead to defective pronephric kidney function in the zebrafish that mimics human disease. This supports the use of the zebrafish pronephros as a valid system to study kidney physiology and for rapid identification of potential therapeutic drugs and strategies in combating renal disease.


Assuntos
Nefropatias/metabolismo , Rim/metabolismo , Proteínas de Peixe-Zebra/metabolismo , Peixe-Zebra/metabolismo , Animais , Modelos Animais de Doenças , Regulação da Expressão Gênica , Humanos , Transporte de Íons , Rim/embriologia , Rim/fisiopatologia , Nefropatias/genética , Nefropatias/fisiopatologia , Células-Tronco/metabolismo , Peixe-Zebra/embriologia , Peixe-Zebra/genética , Proteínas de Peixe-Zebra/genética
14.
Dev Biol ; 334(1): 1-9, 2009 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-19393641

RESUMO

The glomerular filtration barrier is necessary for the selective passage of low molecular weight waste products and the retention of blood plasma proteins. Damage to the filter results in proteinuria. The filtration barrier is the major pathogenic site in almost all glomerular diseases and its study is therefore of clinical significance. We have taken advantage of the zebrafish pronephros as a system for studying glomerular filtration. In order to identify new regulators of filtration barrier assembly, we have performed a reverse genetic screen in the zebrafish testing a group of genes which are enriched in their expression within the mammalian glomerulus. In this novel screen, we have coupled gene knockdown using morpholinos with a physiological glomerular dye filtration assay to test for selective glomerular permeability in living zebrafish larvae. Screening 20 genes resulted in the identification of ralgps1, rapgef2, rabgef1, and crb2b. The crumbs (crb) genes encode a family of evolutionarily conserved proteins important for apical-basal polarity within epithelia. The crb2b gene is expressed in zebrafish podocytes. Electron microscopic analysis of crb2b morphants reveals a gross disorganization of podocyte foot process architecture and loss of slit diaphragms while overall polarity is maintained. Nephrin, a major component of the slit diaphragm, is apically mis-localized in podocytes from crb2b morphants suggesting that crb2b is required for the proper protein trafficking of Nephrin. This report is the first to show a role for crb function in podocyte differentiation. Furthermore, these results suggest a novel link between epithelial polarization and the maintenance of a functional filtration barrier.


Assuntos
Glomérulos Renais/metabolismo , Proteínas de Membrana/genética , Proteínas de Membrana/metabolismo , Proteínas de Peixe-Zebra/genética , Proteínas de Peixe-Zebra/metabolismo , Peixe-Zebra/metabolismo , Animais , Diferenciação Celular , Polaridade Celular/fisiologia , Podócitos/citologia , Podócitos/metabolismo , Podócitos/ultraestrutura
15.
Genes Dev ; 21(16): 2055-68, 2007 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-17699752

RESUMO

The development of the embryonic vascular system into a highly ordered network requires precise control over the migration and branching of endothelial cells (ECs). We have previously identified angiomotin (Amot) as a receptor for the angiogenesis inhibitor angiostatin. Furthermore, DNA vaccination targeting Amot inhibits angiogenesis and tumor growth. However, little is known regarding the role of Amot in physiological angiogenesis. We therefore investigated the role of Amot in embryonic neovascularization during zebrafish and mouse embryogenesis. Here we report that knockdown of Amot in zebrafish reduced the number of filopodia of endothelial tip cells and severely impaired the migration of intersegmental vessels. We further show that 75% of Amot knockout mice die between embryonic day 11 (E11) and E11.5 and exhibit severe vascular insufficiency in the intersomitic region as well as dilated vessels in the brain. Furthermore, using ECs differentiated from embryonic stem (ES) cells, we demonstrate that Amot-deficient cells have intact response to vascular endothelial growth factor (VEGF) in regard to differentiation and proliferation. However, the chemotactic response to VEGF was abolished in Amot-deficient cells. We provide evidence that Amot is important for endothelial polarization during migration and that Amot controls Rac1 activity in endothelial and epithelial cells. Our data demonstrate a critical role for Amot during vascular patterning and endothelial polarization.


Assuntos
Peptídeos e Proteínas de Sinalização Intercelular/fisiologia , Proteínas de Membrana/fisiologia , Proteínas dos Microfilamentos/fisiologia , Neovascularização Fisiológica/fisiologia , Proteínas de Peixe-Zebra/fisiologia , Peixe-Zebra/embriologia , Peixe-Zebra/fisiologia , Angiomotinas , Animais , Sequência de Bases , Padronização Corporal/genética , Padronização Corporal/fisiologia , Linhagem Celular , Movimento Celular/genética , Movimento Celular/fisiologia , Primers do DNA/genética , Células Endoteliais/citologia , Células Endoteliais/fisiologia , Feminino , Deleção de Genes , Inativação Gênica , Humanos , Peptídeos e Proteínas de Sinalização Intercelular/deficiência , Peptídeos e Proteínas de Sinalização Intercelular/genética , Proteínas de Membrana/deficiência , Proteínas de Membrana/genética , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Proteínas dos Microfilamentos/deficiência , Proteínas dos Microfilamentos/genética , Neovascularização Fisiológica/genética , Fenótipo , Gravidez , Pseudópodes/ultraestrutura , Peixe-Zebra/genética , Proteínas de Peixe-Zebra/deficiência , Proteínas de Peixe-Zebra/genética , Proteínas rac1 de Ligação ao GTP/metabolismo
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