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1.
Dev Biol ; 427(1): 121-130, 2017 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-28478097

RESUMO

In kidney development, connection of the nephric duct (ND) to the cloaca and subsequent sprouting of the ureteric bud (UB) from the ND are important for urinary exit tract formation. Although the roles of Ret signaling are well established, it remains unclear how intracellular cytoskeletal proteins regulate these morphogenetic processes. Myh9 and Myh10 encode two different non-muscle myosin II heavy chains, and Myh9 mutations in humans are implicated in congenital kidney diseases. Here we report that ND/UB lineage-specific deletion of Myh9/Myh10 in mice caused severe hydroureter/hydronephrosis at birth. At mid-gestation, the mutant ND/UB epithelia exhibited aberrant basal protrusion and ectopic UB formation, which likely led to misconnection of the ureter to the bladder. In addition, the mutant epithelia exhibited apical extrusion followed by massive apoptosis in the lumen, which could be explained by reduced apical constriction and intercellular adhesion mediated by E-cadherin. These phenotypes were not ameliorated by genetic reduction of the tyrosine kinase receptor Ret. In contrast, ERK was activated in the mutant cells and its chemical inhibition partially ameliorated the phenotypes. Thus, myosin II is essential for maintaining the apicobasal integrity of the developing kidney epithelia independently of Ret signaling.


Assuntos
Epitélio/anormalidades , Rim/embriologia , Miosina não Muscular Tipo IIA/metabolismo , Miosina não Muscular Tipo IIB/metabolismo , Ureter/anormalidades , Bexiga Urinária/anormalidades , Animais , Animais Recém-Nascidos , Cães , Epitélio/metabolismo , Regulação da Expressão Gênica no Desenvolvimento , Imuno-Histoquímica , Hibridização In Situ , Rim/metabolismo , Células Madin Darby de Rim Canino , Camundongos Endogâmicos C57BL , Camundongos Knockout , Camundongos Transgênicos , Microscopia Confocal , Cadeias Pesadas de Miosina/genética , Cadeias Pesadas de Miosina/metabolismo , Néfrons/anormalidades , Néfrons/metabolismo , Miosina não Muscular Tipo IIA/genética , Miosina não Muscular Tipo IIB/genética , Proteínas Proto-Oncogênicas c-ret/genética , Proteínas Proto-Oncogênicas c-ret/metabolismo , Ureter/metabolismo , Bexiga Urinária/metabolismo
2.
Hum Mol Genet ; 25(3): 437-47, 2016 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-26604140

RESUMO

Pallister-Hall syndrome (PHS) is a rare disorder caused by mutations in GLI3 that produce a transcriptional repressor (GLI3R). Individuals with PHS present with a variably penetrant variety of urogenital system malformations, including renal aplasia or hypoplasia, hydroureter, hydronephrosis or a common urogenital sinus. The embryologic mechanisms controlled by GLI3R that result in these pathologic phenotypes are undefined. We demonstrate that germline expression of GLI3R causes renal hypoplasia, associated with decreased nephron number, and hydroureter and hydronephrosis, caused by blind-ending ureters. Mice with obligate GLI3R expression also displayed duplication of the ureters that was caused by aberrant common nephric duct patterning and ureteric stalk outgrowth. These developmental abnormalities are associated with suppressed Hedgehog signaling activity in the cloaca and adjacent vesicular mesenchyme. Mice with conditional expression of GLI3R were utilized to identify lineage-specific effects of GLI3R. In the ureteric bud, GLI3R expression decreased branching morphogenesis. In Six2-positive nephrogenic progenitors, GLI3R decreased progenitor cell proliferation reducing the number of nephrogenic precursor structures. Using mutant mice with Gli3R and Gli3 null alleles, we demonstrate that urogenital system patterning and development is controlled by the levels of GLI3R and not by an absence of full-length GLI3. We conclude that the urogenital system phenotypes observed in PHS are caused by GLI3R-dependent perturbations in nephric duct patterning, renal branching morphogenesis and nephrogenic progenitor self-renewal.


Assuntos
Linhagem da Célula/genética , Regulação da Expressão Gênica no Desenvolvimento , Hidronefrose/genética , Rim/anormalidades , Fatores de Transcrição Kruppel-Like/genética , Proteínas do Tecido Nervoso/genética , Síndrome de Pallister-Hall/genética , Anormalidades Urogenitais/genética , Animais , Padronização Corporal/genética , Proliferação de Células , Modelos Animais de Doenças , Embrião de Mamíferos , Proteínas de Homeodomínio/genética , Proteínas de Homeodomínio/metabolismo , Humanos , Hidronefrose/metabolismo , Hidronefrose/patologia , Rim/metabolismo , Rim/patologia , Fatores de Transcrição Kruppel-Like/metabolismo , Camundongos , Camundongos Knockout , Mutação , Néfrons/anormalidades , Néfrons/embriologia , Néfrons/metabolismo , Proteínas do Tecido Nervoso/metabolismo , Síndrome de Pallister-Hall/metabolismo , Síndrome de Pallister-Hall/patologia , Fenótipo , Transdução de Sinais , Células-Tronco/metabolismo , Células-Tronco/patologia , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Ureter/anormalidades , Ureter/embriologia , Ureter/metabolismo , Anormalidades Urogenitais/metabolismo , Anormalidades Urogenitais/patologia , Proteína Gli3 com Dedos de Zinco
3.
Development ; 142(7): 1254-66, 2015 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-25804736

RESUMO

Development of the metanephric kidney depends on tightly regulated interplay between self-renewal and differentiation of a nephron progenitor cell (NPC) pool. Several key factors required for the survival of NPCs have been identified, including fibroblast growth factor (FGF) signaling and the transcription factor Wilms' tumor suppressor 1 (WT1). Here, we present evidence that WT1 modulates FGF signaling by activating the expression of growth arrest-specific 1 (Gas1), a novel WT1 target gene and novel modulator of FGF signaling. We show that WT1 directly binds to a conserved DNA binding motif within the Gas1 promoter and activates Gas1 mRNA transcription in NPCs. We confirm that WT1 is required for Gas1 expression in kidneys in vivo. Loss of function of GAS1 in vivo results in hypoplastic kidneys with reduced nephron mass due to premature depletion of NPCs. Although kidney development in Gas1 knockout mice progresses normally until E15.5, NPCs show decreased rates of proliferation at this stage and are depleted as of E17.5. Lastly, we show that Gas1 is selectively required for FGF-stimulated AKT signaling in vitro. In summary, our data suggest a model in which WT1 modulates receptor tyrosine kinase signaling in NPCs by directing the expression of Gas1.


Assuntos
Proteínas de Ciclo Celular/metabolismo , Fatores de Crescimento de Fibroblastos/metabolismo , Néfrons/metabolismo , Transdução de Sinais , Células-Tronco/metabolismo , Proteínas WT1/metabolismo , Animais , Proteínas de Ciclo Celular/genética , Proliferação de Células , DNA/genética , Ativação Enzimática/efeitos dos fármacos , Proteínas Ligadas por GPI/genética , Proteínas Ligadas por GPI/metabolismo , Regulação da Expressão Gênica no Desenvolvimento , Técnicas de Silenciamento de Genes , Camundongos Knockout , Modelos Animais , Néfrons/anormalidades , Néfrons/embriologia , Néfrons/patologia , Técnicas de Cultura de Órgãos , Regiões Promotoras Genéticas/genética , Ligação Proteica , Proteínas Proto-Oncogênicas c-akt/metabolismo , Proteínas Proto-Oncogênicas c-ret/metabolismo , RNA Mensageiro/genética , RNA Mensageiro/metabolismo
4.
Am J Physiol Renal Physiol ; 306(7): F764-72, 2014 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-24500693

RESUMO

MicroRNAs (miRNAs) are small, noncoding regulatory RNAs that act as posttranscriptional repressors by binding to the 3'-untranslated region (3'-UTR) of target genes. They require processing by Dicer, an RNase III enzyme, to become mature regulatory RNAs. Previous work from our laboratory revealed critical roles for miRNAs in nephron progenitors at midgestation (Ho J, Pandey P, Schatton T, Sims-Lucas S, Khalid M, Frank MH, Hartwig S, Kreidberg JA. J Am Soc Nephrol 22: 1053-1063, 2011). To interrogate roles for miRNAs in the early metanephric mesenchyme, which gives rise to nephron progenitors as well as the renal stroma during kidney development, we conditionally ablated Dicer function in this lineage. Despite normal ureteric bud outgrowth and condensation of the metanephric mesenchyme to form nephron progenitors, early loss of miRNAs in the metanephric mesenchyme resulted in severe renal dysgenesis. Nephron progenitors are initially correctly specified in the mutant kidneys, with normal expression of several transcription factors known to be critical in progenitors, including Six2, Pax2, Sall1, and Wt1. However, there is premature loss of the nephron progenitor marker Cited1, marked apoptosis, and increased expression of the proapoptotic protein Bim shortly after the initial inductive events in early kidney development. Subsequently, there is a failure in ureteric bud branching and nephron progenitor differentiation. Taken together, our data demonstrate a previously undetermined requirement for miRNAs during early kidney organogenesis and indicate a crucial role for miRNAs in regulating the survival of this lineage.


Assuntos
RNA Helicases DEAD-box/metabolismo , Células-Tronco Embrionárias/enzimologia , Rim/enzimologia , Mesoderma/enzimologia , Ribonuclease III/metabolismo , Animais , Apoptose , Proteínas Reguladoras de Apoptose/genética , Proteínas Reguladoras de Apoptose/metabolismo , Proteína 11 Semelhante a Bcl-2 , RNA Helicases DEAD-box/deficiência , RNA Helicases DEAD-box/genética , Regulação da Expressão Gênica no Desenvolvimento , Regulação Enzimológica da Expressão Gênica , Idade Gestacional , Rim/anormalidades , Proteínas de Membrana/genética , Proteínas de Membrana/metabolismo , Mesoderma/anormalidades , Camundongos , Camundongos Knockout , MicroRNAs/metabolismo , Néfrons/anormalidades , Néfrons/enzimologia , Proteínas Nucleares/genética , Proteínas Nucleares/metabolismo , Organogênese , Proteínas Proto-Oncogênicas/genética , Proteínas Proto-Oncogênicas/metabolismo , Ribonuclease III/deficiência , Ribonuclease III/genética , Transativadores/genética , Transativadores/metabolismo , Ureter/anormalidades , Ureter/enzimologia
5.
Reprod Fertil Dev ; 26(7): 1032-43, 2014 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-23910917

RESUMO

A developmental insult that restricts growth in the first generation has the potential to program disease in subsequent generations. The aim of this study was to ascertain transgenerational growth and cardio-renal effects, via the maternal line, in a rat model of utero-placental insufficiency. Bilateral uterine vessel ligation or sham surgery (offspring termed first generation; F1 Restricted and Control, respectively) was performed in WKY rats. F1 Restricted and Control females were mated with normal males to produce second generation (F2) offspring (Restricted and Control) studied from fetal (embryonic Day 20) to adult (12 months) life. F2 Restricted male and female fetuses had reduced (P<0.05) nephron number (down 15-22%) but this deficit was not sustained postnatally and levels were similar to Controls at Day 35. F2 Restricted males, but not females, developed elevated (+16mmHg, P<0.05) systolic blood pressure at 6 months of age, which was sustained to 9 months. This was not explained by alterations to intra-renal or plasma components of the renin-angiotensin system. In a rat model of utero-placental insufficiency, we report alterations to F2 kidney development and sex-specific adult hypertension. This study demonstrates that low birthweight can have far-reaching effects that extend into the next generation.


Assuntos
Hipertensão/etiologia , Néfrons/anormalidades , Animais , Animais Recém-Nascidos/crescimento & desenvolvimento , Peso Corporal , Feminino , Retardo do Crescimento Fetal/fisiopatologia , Rim/embriologia , Masculino , Néfrons/embriologia , Tamanho do Órgão , Circulação Placentária/fisiologia , Insuficiência Placentária/fisiopatologia , Gravidez , Ratos , Ratos Endogâmicos WKY , Sistema Renina-Angiotensina , Fatores Sexuais , Útero/irrigação sanguínea
6.
J Am Soc Nephrol ; 24(7): 1127-38, 2013 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-23661808

RESUMO

DLG1 (discs-large homolog 1) and CASK (calcium/calmodulin-dependent serine protein kinase) interact at membrane-cytoskeleton interfaces and function as scaffolding proteins that link signaling molecules, receptors, and other scaffolding proteins at intercellular and synaptic junctions. Dlg1-null mice exhibit hydronephrosis, hydroureter, and occasionally hypoplastic kidneys, whereas Cask-null mice do not. To investigate whether DLG1 and CASK cooperate in the developing urogenital system, we generated mice deficient in both DLG1 and CASK either 1) globally, 2) in metanephric mesenchyme, or 3) in nephron progenitors. With each approach, Dlg1;Cask double-knockout (DKO) kidneys were severely hypoplastic and dysplastic and demonstrated rapid, premature depletion of nephron progenitors/stem cells. Several cellular and molecular defects were observed in the DKO kidneys, including reduced proliferation and increased apoptosis of cells in the nephrogenic zone and a progressive decrease in the number of cells expressing SIX2, a transcription factor essential for maintaining nephron progenitors. Fgf8 expression was reduced in early-stage DKO metanephric mesenchyme, accompanied by reduced levels of components of the Ras pathway, which is activated by fibroblast growth factor (FGF) signaling. Moreover, Dlg1(+/-);Cask(-/-) (het/null) kidneys were moderately hypoplastic and demonstrated impaired aggregation of SIX2-positive cells around the ureteric bud tips. Nephron progenitor-specific het/null mice survived with small kidneys but developed glomerulocystic kidney disease and renal failure. Taken together, these results suggest that DLG1 and CASK play critical cooperative roles in maintaining the nephron progenitor population, potentially via a mechanism involving effects on FGF signaling.


Assuntos
Diferenciação Celular , Guanilato Quinases/metabolismo , Néfrons/embriologia , Proteínas do Tecido Nervoso/metabolismo , Organogênese , Células-Tronco/citologia , Animais , Proteína 1 Homóloga a Discs-Large , Expressão Gênica , Camundongos , Camundongos Knockout , Néfrons/anormalidades , Néfrons/metabolismo , Proteínas Associadas SAP90-PSD95 , Transdução de Sinais
7.
Am J Physiol Regul Integr Comp Physiol ; 301(3): R682-9, 2011 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-21653879

RESUMO

Suboptimal kidney development resulting from a genetic deficit in nephron number can have lifelong consequences that may lead to cardiorenal complications upon exposure to secondary insults in later life. To determine whether the inherited reduced renal reserve compromises the ability to handle osmotic stress in the adult animal, we challenged the heterozygous 3H1 Brachyrrhine (Br/+) mouse, which displays heritable renal hypoplasia associated with reduced embryonic six2 expression, to a solution of 2% NaCl for 5 days or to fluid restriction for 48 h. Blood chemistry, fluid intake, and physiological parameters, including renal measurements, were determined. Systemic hypertonicity by prolonged salt loading led to significant increases in plasma osmolality and plasma Na(+), along with polydipsia and polyuria, with a significant urine-concentrating defect that was resistant to DDAVP treatment in the adult Br/+ mouse compared with wild-type littermates. The Br/+ mouse also developed a significant increase in blood urea nitrogen at baseline that was further elevated when 2% NaCl was given. Fluid restriction for 48 h further enhanced plasma osmolality and plasma Na(+) responses, although the Br/+ mouse was evidently able to produce a small amount of concentrated urine at this time. Hypothalamic c-Fos expression was appropriately activated in the Br/+ mouse in response to both osmotic challenges, indicating an intact central neuroendocrine pathway that was not affected by the lack of congenital six2 expression. Collectively, our results demonstrate impaired osmoregulatory mechanisms consistent with chronic renal failure in the Br/+ mouse and indicate that six2 haploinsufficiency has a direct effect on postnatal fluid and electrolyte handling associated with fluid imbalance.


Assuntos
Falência Renal Crônica/metabolismo , Néfrons/metabolismo , Fatores de Transcrição/deficiência , Equilíbrio Hidroeletrolítico , Análise de Variância , Animais , Antidiuréticos/administração & dosagem , Nitrogênio da Ureia Sanguínea , Desamino Arginina Vasopressina/administração & dosagem , Ingestão de Líquidos , Regulação da Expressão Gênica no Desenvolvimento , Haploinsuficiência , Proteínas de Homeodomínio/genética , Hipotálamo/metabolismo , Hipotálamo/fisiopatologia , Capacidade de Concentração Renal , Falência Renal Crônica/genética , Falência Renal Crônica/fisiopatologia , Camundongos , Camundongos Mutantes , Néfrons/anormalidades , Néfrons/efeitos dos fármacos , Néfrons/fisiopatologia , Organogênese , Concentração Osmolar , Poliúria/genética , Poliúria/metabolismo , Poliúria/fisiopatologia , Proteínas Proto-Oncogênicas c-fos/metabolismo , Solução Salina Hipertônica/administração & dosagem , Solução Salina Hipertônica/metabolismo , Sódio/sangue , Cloreto de Sódio na Dieta/administração & dosagem , Cloreto de Sódio na Dieta/metabolismo , Fatores de Transcrição/genética , Equilíbrio Hidroeletrolítico/efeitos dos fármacos , Equilíbrio Hidroeletrolítico/genética
8.
Rev. méd. hondur ; 79(2): 79-80, abr.-jun. 2011. ilus
Artigo em Espanhol | LILACS | ID: lil-644956

RESUMO

Introducción. La agenesia renal bilateral es una anomalía congénita mortal rara, originada por la ausencia del desarrollo de las nefronas y fallo de la división del esbozo ureteral. Caso clínico. Paciente femenino de 25 años de edad con embarazo de 33 semanas 3 días de gestación referida para nuevos estudios de imagen por su médico tratante debido a sospecha de agenesia renal bilateral en su feto, en ultrasonido convencional. No había historia personal o familiar relevante. Se le practicó un ultrasonido obstétrico convencional y doppler color con reconstrucciones tridimensionales, demostrando en el feto, la ausencia de las arterias renales y riñones, con signo de la suprarrenal tumbada. Se observó, además agenesia vesical, mesocardia con dextroposición, tórax en campana con hipoplasia pulmonar y anhidramnios. Ocurrió óbito a las 35 semanas. Conclusión. Los hallazgos fueron congruentes con agenesia renal bilateral, con pronóstico fatal en el tercer trimestre del embarazo.


Assuntos
Humanos , Adulto , Feminino , Complicações na Gravidez , Néfrons/anormalidades , Rim/anormalidades , Transmissão Vertical de Doenças Infecciosas , Ultrassonografia Doppler/métodos
9.
Am J Physiol Renal Physiol ; 300(1): F147-56, 2011 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-20962117

RESUMO

A hyperglycemic environment in utero reduces kidney size and nephron number due to nascent nephron apoptosis. However, the underlying mechanisms are incompletely understood. The present study investigated whether the nascent nephron apoptosis promoted by high glucose is mediated via the transcription factor NF-κB and p53 signaling pathways. Neonatal mouse kidneys from the offspring of nondiabetic, diabetic, and insulin-treated diabetic dams were used for in vivo studies, and MK4 cells, an embryonic metanephric mesenchymal (MM) cell line, were used for in vitro studies. Neonatal kidneys of the offspring of diabetic mothers exhibited an increased number of apoptotic cells and reactive oxygen species (ROS) generation, enhanced NF-κB activation, and nuclear translocation of its subunits (p50 and p65 subunits) as well as phosphorylation (Ser 15) of p53 compared with kidneys of offspring of nondiabetic mothers. Insulin treatment of diabetic dams normalized these parameters in the offspring. In vitro, high-glucose (25 mM) induced ROS generation and significantly increased MK4 cell apoptosis and caspase-3 activity via activation of NF-κB pathway, with p53 phosphorylation and nuclear translocation compared with normal glucose (5 mM). These changes in a high-glucose milieu were prevented by transient transfection of small interfering RNAs for dominant negative IκBα or IKK or p53. Our data demonstrate that high glucose-induced nascent nephron apoptosis is mediated, at least in part, via ROS generation and the activation of NF-κB and p53 pathways.


Assuntos
Apoptose/efeitos dos fármacos , Diabetes Mellitus Experimental/fisiopatologia , Glucose/farmacologia , NF-kappa B/fisiologia , Néfrons/efeitos dos fármacos , Proteína Supressora de Tumor p53/fisiologia , Animais , Linhagem Celular , Feminino , Glucose/administração & dosagem , Insulina/uso terapêutico , Rim/anormalidades , Camundongos , Subunidade p50 de NF-kappa B/biossíntese , Néfrons/anormalidades , Gravidez , Gravidez em Diabéticas/tratamento farmacológico , Gravidez em Diabéticas/fisiopatologia , Fator de Transcrição RelA/biossíntese
10.
Lab Invest ; 90(1): 83-97, 2010 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-19918242

RESUMO

Reduced nephron numbers may predispose to renal failure. We hypothesized that glucose transporters (GLUTs) may contribute to progression of the renal disease, as GLUTs have been implicated in diabetic glomerulosclerosis and hypertensive renal disease with mesangial cell (MC) stretch. The Os (oligosyndactyly) allele that typically reduces nephron number by approximately 50%, was repeatedly backcrossed from ROP (Ra/+ (ragged), Os/+ (oligosyndactyly), and Pt/+ (pintail)) Os/+ mice more than six times into the Fvb mouse background to obtain Os/+ and +/+ mice with the Fvb background for study. Glomerular function, GLUT1, signaling, albumin excretion, and structural and ultrastructural changes were assessed. The FvbROP Os/+ mice (Fvb background) exhibited increased glomerular GLUT1, glucose uptake, VEGF, glomerular hypertrophy, hyperfiltration, extensive podocyte foot process effacement, marked albuminuria, severe extracellular matrix (ECM) protein deposition, and rapidly progressive renal failure leading to their early demise. Glomerular GLUT1 was increased 2.7-fold in the FvbROP Os/+ mice vs controls at 4 weeks of age, and glucose uptake was increased 2.7-fold. These changes were associated with the activation of glomerular PKCbeta1 and NF-kappaB p50 which contribute to ECM accumulation. The cyclic mechanical stretch of MCs in vitro, used as a model for increased MC stretch in vivo, reproduced increased GLUT1 at 48 h, a stimulus for increased VEGF expression which followed at 72 h. VEGF was also shown to act in a positive feedback manner on MC GLUT1, increasing GLUT1 expression, glucose uptake and fibronectin (FN) accumulation in vitro, whereas antisense suppression of GLUT1 largely blocked FN upregulation by VEGF. The FvbROP Os/+ mice exhibited an early increase in glomerular GLUT1 leading to increased glomerular glucose uptake PKCbeta1, and NF-kappaB activation, with excess ECM accumulation. A GLUT1-VEGF-GLUT1 positive feedback loop may play a key role in contributing to renal disease in this model of nondiabetic glomerulosclerosis.


Assuntos
Albuminúria/etiologia , Transportador de Glucose Tipo 1/metabolismo , Camundongos Mutantes/metabolismo , Néfrons/anormalidades , Insuficiência Renal/etiologia , Insuficiência Renal/fisiopatologia , Fator A de Crescimento do Endotélio Vascular/metabolismo , Alelos , Animais , Células Cultivadas , Creatinina/metabolismo , Progressão da Doença , Proteínas da Matriz Extracelular/metabolismo , Mesângio Glomerular/metabolismo , Mesângio Glomerular/patologia , Imuno-Histoquímica , Isoenzimas/metabolismo , Rim/crescimento & desenvolvimento , Rim/metabolismo , Rim/patologia , Glomérulos Renais/metabolismo , Glomérulos Renais/patologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Mutantes/genética , Microscopia Eletrônica , NF-kappa B/metabolismo , Proteína Quinase C/metabolismo , Estresse Mecânico , Sindactilia/genética , Fator de Crescimento Transformador beta1/metabolismo , Regulação para Cima
11.
Am J Physiol Renal Physiol ; 296(5): F1166-78, 2009 May.
Artigo em Inglês | MEDLINE | ID: mdl-19193724

RESUMO

The Br/+ mutant mouse displays decreased embryological expression of the homeobox transcription factor Six2, resulting in hertitable renal hypoplasia. The purpose of this study was to characterize the renal physiological consequences of embryonic haploinsuffiency of Six2 by analyzing renal morphology and function in the adult Br heterozygous mutant. Adult Br/+ kidneys weighed 50% less than those from wild-type mice and displayed glomerulopathy. Stereological analysis of renal glomeruli showed that Br/+ kidneys had an average of 88% fewer glomeruli than +/+ kidneys, whereas individual glomeruli in Br/+ mice maintained an average volume increase of 180% compared with normal nephrons. Immunostaining revealed increased levels of endothelin-1 (ET-1), endothelin receptors A (ET(A)) and B (ET(B)), and Na-K-ATPase were present in the dilated renal tubules of mutant mice. Physiological features of chronic renal failure (CRF) including elevated mean arterial pressure, increased plasma creatinine, and dilute urine excretion were measured in Br/+ mutant mice. Electron microscopy of the Br/+ glomeruli revealed pathological alterations such as hypercellularity, extracellular matrix accumulation, and a thick irregular glomerular basement membrane. These results indicate that adult Br/+ mice suffer from CRF associated with reduced nephron number and renal hypoplasia, as well as glomerulopathy. Defects are associated with embryological deficiencies of Six2, suggesting that proper levels of this protein during nephrogenesis are critical for normal glomerular development and adult renal function.


Assuntos
Proteínas de Homeodomínio/genética , Hipertensão Renal/fisiopatologia , Falência Renal Crônica/fisiopatologia , Néfrons/anormalidades , Néfrons/fisiologia , Fatores de Transcrição/genética , Animais , Regulação para Baixo/fisiologia , Endotelina-1/metabolismo , Regulação da Expressão Gênica no Desenvolvimento/fisiologia , Hipertensão Renal/genética , Hipertensão Renal/patologia , Falência Renal Crônica/genética , Falência Renal Crônica/patologia , Glomérulos Renais/anormalidades , Glomérulos Renais/fisiologia , Glomérulos Renais/ultraestrutura , Túbulos Renais/anormalidades , Túbulos Renais/fisiologia , Túbulos Renais/ultraestrutura , Camundongos , Camundongos Endogâmicos C3H , Camundongos Mutantes , Microscopia Eletrônica , Néfrons/ultraestrutura , Receptores de Endotelina/metabolismo , ATPase Trocadora de Sódio-Potássio/metabolismo
12.
J Am Soc Nephrol ; 19(10): 2027-34, 2008 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-18820179

RESUMO

Congenital nephron number varies five-fold among normal humans, and individuals at the lower end of this range may have an increased lifetime risk for essential hypertension or renal insufficiency; however, the mechanisms that determine nephron number are unknown. This study tested the hypothesis that common hypomorphic variants of the RET gene, which encodes a tyrosine kinase receptor critical for renal branching morphogenesis, might account for subtle renal hypoplasia in some normal newborns. A common single-nucleotide polymorphism (rs1800860 G/A) was identified within an exonic splicing enhancer in exon 7. The adenosine variant at mRNA position 1476 reduced affinity for spliceosome proteins, enhanced the likelihood of aberrant mRNA splicing, and diminished the level of functional transcript in human cells. In vivo, normal white newborns with an rs1800860(1476A) allele had kidney volumes 10% smaller and cord blood cystatin C levels 9% higher than those with the rs1800860(1476G) allele. These findings suggest that the RET(1476A) allele, in combination with other common polymorphic developmental genes, may account for subtle renal hypoplasia in a significant proportion of the white population. Whether this gene variant affects clinical outcomes requires further study.


Assuntos
Néfrons/anormalidades , Polimorfismo de Nucleotídeo Único/genética , Proteínas Proto-Oncogênicas c-ret/genética , Estudos de Casos e Controles , Técnicas de Cultura de Células , Linhagem Celular Tumoral , Estudos de Coortes , Cistatina C , Cistatinas/sangue , Éxons , Humanos , Lactente , Recém-Nascido , Tamanho do Órgão , Splicing de RNA
13.
Dev Dyn ; 237(9): 2450-9, 2008 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-18729219

RESUMO

Bcl-2 is the founding member of a family of proteins that influence apoptosis. Loss of bcl-2 results in renal hypoplasia/cystic dysplasia at birth. Here, we examined whether re-expression of bcl-2 throughout the ureteric bud and its derived epithelia would restore a normal renal phenotype in bcl-2 -/- mice. Re-expression of bcl-2 in the ureteric bud/collecting duct of bcl-2 -/- mice increased nephron numbers, diminished glomerular hypertrophy, and increased nephrogenic zone size. Unlike bcl-2 -/- mice which have gross renal cyst formation, few renal cysts were present in mice re-expressing bcl-2. We have previously shown increased apoptosis and proliferation, as well as aberrant protein tyrosine phosphatase 1B expression, accompanied cystic changes in bcl-2 -/- mice. These changes were not observed when bcl-2 was re-expressed in the ureteric bud/collecting duct system. Thus, expression of bcl-2 in the ureteric bud/collecting duct resulted in increased nephron numbers partially rescuing renal hypoplasia/cystic dysplasia in bcl-2 -/- mice.


Assuntos
Epitélio/metabolismo , Rim/metabolismo , Proteínas Proto-Oncogênicas c-bcl-2/fisiologia , Ureter/metabolismo , Animais , Western Blotting , Epitélio/embriologia , Feminino , Regulação da Expressão Gênica no Desenvolvimento , Imuno-Histoquímica , Rim/anormalidades , Camundongos , Camundongos Knockout , Camundongos Transgênicos , Néfrons/anormalidades , Néfrons/metabolismo , Gravidez , Proteínas Proto-Oncogênicas c-bcl-2/genética , Proteínas Proto-Oncogênicas c-bcl-2/metabolismo , Ureter/citologia , Ureter/embriologia
14.
Pediatr Nephrol ; 22(11): 1861-7, 2007 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-17849154

RESUMO

A reduced nephron complement at birth renders the kidney susceptible to renal disease in adulthood. Retinoic acid (RA; the active metabolite of vitamin A) is linked to nephrogenesis in vitro and in vivo. The aim of this study was to determine the effect of administration of retinoic acid in midgestation in rats on nephron endowment in offspring exposed to maternal protein restriction. Rats were fed either a normal-protein diet (NPD) or a low-protein diet (LPD) during pregnancy and lactation. Half of the dams in the LPD group were injected intraperitoneally with retinoic acid (20 mg/kg) during gestation at embryonic day 11.5. At 4 weeks of age, the offspring were anesthetized and perfusion-fixed, and nephron number estimated using unbiased stereological techniques. Body weight and kidney volume was significantly reduced in all LPD offspring. There was a significant 29% reduction in nephron number in the LPD group compared with the NPD offspring, whereas the number of nephrons in kidneys from the LPD + RA offspring was not significantly different compared with controls. In conclusion, administration of a single bolus dose of retinoic acid during midgestation restored nephron endowment to normal in offspring exposed to maternal protein restriction.


Assuntos
Antineoplásicos/farmacologia , Proteínas Alimentares/farmacologia , Transtornos da Nutrição Fetal/tratamento farmacológico , Néfrons/anormalidades , Efeitos Tardios da Exposição Pré-Natal/tratamento farmacológico , Tretinoína/farmacologia , Animais , Peso Corporal/efeitos dos fármacos , Dieta com Restrição de Proteínas , Feminino , Transtornos da Nutrição Fetal/patologia , Idade Gestacional , Injeções Intraperitoneais , Glomérulos Renais/anormalidades , Glomérulos Renais/efeitos dos fármacos , Glomérulos Renais/patologia , Masculino , Néfrons/efeitos dos fármacos , Néfrons/patologia , Tamanho do Órgão/efeitos dos fármacos , Gravidez , Ratos , Ratos Endogâmicos WKY
15.
J Am Soc Nephrol ; 18(6): 1688-96, 2007 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-17442788

RESUMO

Uteroplacental insufficiency in the rat restricts fetal growth, impairs mammary development, compromising postnatal growth; and increases adult BP. The roles of prenatal and postnatal nutritional restraint on later BP and nephron endowment in offspring from mothers that underwent bilateral uterine vessel ligation (restricted) on day 18 of pregnancy were examined. Sham surgery (control) and a group of rats with reduced litter size (reduced; litter size reduced at birth to five, equivalent to restricted group) were used as controls. Offspring (control, reduced, and restricted) were cross-fostered on postnatal day 1 onto a control (normal lactation) or restricted (impaired lactation) mother. BP in male offspring was determined by tail cuff at 8, 12, and 20 wk of age, with glomerular number and volume (Cavalieri/Physical Dissector method) and renal angiotensin II type 1 receptor (AT(1)R) mRNA expression (real-time PCR) determined at 6 mo. Restricted-on-restricted male offspring developed hypertension (+16 mmHg) by 20 wk together with a nephron deficit (-26%) and glomerular hypertrophy (P < 0.05). In contrast, providing a normal lactational environment to restricted offspring improved postnatal growth and prevented the nephron deficit and hypertension. Reduced-on-restricted pups that were born of normal weight but with impaired growth during lactation subsequently grew faster, developed hypertension (+16 mmHg), had increased AT(1A)R and AT(1B)R mRNA expression (P < 0.05), but had no nephron deficit. Our study identifies the prenatal and postnatal nutritional environments in the programming of adult hypertension, associated with distinct renal changes. It is shown for the first time that a prenatally induced nephron deficit can be restored by correcting growth restriction during lactation.


Assuntos
Retardo do Crescimento Fetal/patologia , Hipertensão Renal/patologia , Hipertensão Renal/prevenção & controle , Leite , Néfrons/anormalidades , Animais , Animais Lactentes , Peso ao Nascer , Pressão Sanguínea , Feminino , Retardo do Crescimento Fetal/fisiopatologia , Hipertensão Renal/fisiopatologia , Glomérulos Renais/anormalidades , Glomérulos Renais/citologia , Glomérulos Renais/fisiologia , Lactação , Tamanho da Ninhada de Vivíparos , Masculino , Néfrons/citologia , Néfrons/fisiologia , Tamanho do Órgão , Gravidez , Efeitos Tardios da Exposição Pré-Natal/patologia , Efeitos Tardios da Exposição Pré-Natal/fisiopatologia , RNA Mensageiro/metabolismo , Ratos , Ratos Endogâmicos WKY , Receptor Tipo 1 de Angiotensina/genética , Receptor Tipo 1 de Angiotensina/metabolismo
17.
Kidney Int ; 68(3): 955-65, 2005 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-16105026

RESUMO

BACKGROUND: During development of the permanent mammalian kidney (metanephros) several key epithelial events occur such as ureteric branching morphogenesis and nephrogenesis. One of the first stages of nephrogenesis involves the conversion of mesenchymal cells to epithelial cells, and thus the metanephros provides an excellent model to study epithelial polarization. The aim of this study was to investigate the role of the epithelial polarity gene, discs large 1 (dlg1), during development of the mouse kidney. METHODS: We utilized mice with a gene trap vector insertion within dlg1 (dlg(gt)) resulting in a truncated Dlg1 protein, lacking the SH3, protein 4.1 and guanylate kinase-like (GUK) domains, fused to a LacZ reporter. These mice were used to analyze the expression of Dlg1 during kidney development, the subcellular localization of Dlg1 in epithelial cells, and the ability of Dlg1 to bind to calmodulin-associated serine/threonine kinase (CASK). Metanephric organ culture was used to study branching morphogenesis and nephrogenesis in wild-type and dlg(gt) mutant mice. RESULTS: Dlg1 was expressed in ureteric and mesenchyme-derived epithelial cells during kidney development. Truncation of Dlg1 altered the normal basolateral localization of Dlg1 restricting it to the adherens junction. Due to the loss of the SH3 domain the binding capacity of Dlg1 to CASK was reduced. Nephrogenesis was altered in dlg(gt)/dlg(gt) metanephroi with a 30% decrease in nephron number. CONCLUSION: Our results indicate that the loss of the SH3, protein 4.1 and/or GUK domains of Dlg1 disrupt epithelial polarity and perturb nephrogenesis either as a secondary consequence to a defect in ureteric branching morphogenesis and/or delay in mesenchyme-to- epithelial transition.


Assuntos
Polaridade Celular/fisiologia , Células Epiteliais/fisiologia , Néfrons/anormalidades , Proteínas do Tecido Nervoso/genética , Ureter/anormalidades , Animais , Proteínas Quinases Dependentes de Cálcio-Calmodulina/metabolismo , Proteína 1 Homóloga a Discs-Large , Células Epiteliais/citologia , Feminino , Regulação da Expressão Gênica no Desenvolvimento , Guanilato Quinases , Masculino , Camundongos , Camundongos Endogâmicos , Camundongos Mutantes , Mutagênese , Néfrons/citologia , Néfrons/fisiologia , Proteínas do Tecido Nervoso/química , Proteínas do Tecido Nervoso/metabolismo , Técnicas de Cultura de Órgãos , Gravidez , Estrutura Terciária de Proteína , Proteínas Associadas SAP90-PSD95 , Ureter/citologia , Ureter/fisiologia
18.
Kidney Int ; 68(1): 23-34, 2005 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-15954893

RESUMO

BACKGROUND: Polycystic kidney disease (PKD) is a common hereditary disease. A number of murine and zebrafish mutants have been generated and used for the study of PKD as metanephric and pronephric models, respectively. Here, we report a medaka (Oryzias latipes) mutant that develops numerous cysts in the kidney in adulthood fish in an autosomal-recessive manner as a mesonephric model of PKD. METHODS: The phenotypes of the medaka pc mutant were described in terms of morphologic, histologic, and ultrastructural features. The pc see-through stock was produced by crossing a pc mutant and a fish from the see-through stock and used for observing the kidney through the transparent body wall of a live fish. RESULTS: The mutant developed bilateral massive enlargement of the kidney in adulthood. They sexually matured normally within 2 months of age and died within 6 months of age. The affected kidney was occupied by numerous, fluid-filled cysts, which were lined by attenuated squamous epithelial cells. Developmentally, cystic formation began in the pronephros in 10-day-old fry and in the mesonephros in 20-day-old fry at the microscopic level. The pc see-through stock was useful in observing disease progression in live fish. CONCLUSION: The kidney disorder that develops in the medaka pc mutant is a mesonephric counterpart of PKD, particularly an autosomal-dominant PKD, based on its morphologic, histologic, and ultrastructural features, and slow progression.


Assuntos
Modelos Animais de Doenças , Mesonefro/patologia , Oryzias/genética , Doenças Renais Policísticas/genética , Doenças Renais Policísticas/patologia , Animais , Feminino , Genes Dominantes , Túbulos Renais/anormalidades , Túbulos Renais/patologia , Túbulos Renais/ultraestrutura , Masculino , Mesonefro/ultraestrutura , Microscopia Eletrônica de Varredura , Microscopia Eletrônica de Transmissão , Mutação , Néfrons/anormalidades , Néfrons/patologia , Néfrons/ultraestrutura , Tamanho do Órgão , Oryzias/anormalidades , Fenótipo
19.
Cell ; 106(3): 319-29, 2001 Aug 10.
Artigo em Inglês | MEDLINE | ID: mdl-11509181

RESUMO

Alternative splicing of Wt1 results in the insertion or omission of the three amino acids KTS between zinc fingers 3 and 4. In vitro experiments suggest distinct molecular functions for + and -KTS isoforms. We have generated mouse strains in which specific isoforms have been removed. Heterozygous mice with a reduction of +KTS levels develop glomerulosclerosis and represent a model for Frasier syndrome. Homozygous mutants of both strains die after birth due to kidney defects. Strikingly, mice lacking +KTS isoforms show a complete XY sex reversal due to a dramatic reduction of Sry expression levels. Our data demonstrate distinct functions for the two splice variants and place the +KTS variants as important regulators for Sry in the sex determination pathway.


Assuntos
Processamento Alternativo/genética , Proteínas de Ligação a DNA/genética , Proteínas de Ligação a DNA/metabolismo , Genes do Tumor de Wilms/genética , Néfrons/embriologia , Proteínas Nucleares , Proteínas Repressoras , Processos de Determinação Sexual , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Transporte Ativo do Núcleo Celular , Animais , Animais Recém-Nascidos , Apoptose , Sequência de Bases , Sobrevivência Celular , Receptor Nuclear Órfão DAX-1 , Proteínas de Ligação a DNA/química , Transtornos do Desenvolvimento Sexual , Éxons/genética , Feminino , Glomerulosclerose Segmentar e Focal/genética , Glomerulosclerose Segmentar e Focal/metabolismo , Gônadas/anormalidades , Gônadas/embriologia , Gônadas/metabolismo , Gônadas/patologia , Masculino , Camundongos , Mutagênese/genética , Néfrons/anormalidades , Néfrons/metabolismo , Néfrons/ultraestrutura , Isoformas de Proteínas/química , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismo , Sítios de Splice de RNA/genética , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Receptores do Ácido Retinoico/genética , Proteína da Região Y Determinante do Sexo , Síndrome , Fatores de Transcrição/química , Proteínas WT1
20.
Kidney Int ; 54(5): 1455-62, 1998 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-9844121

RESUMO

BACKGROUND: Vitamin A plays a critical role in fetal organogenesis, and its severe deficiency during pregnancy is known to result in malformations of several organs, including the kidney. However, the consequences of mild vitamin A deficiency (VAD) has received little attention. In the present study, we examined the effect of in utero exposure to mild VAD on renal organogenesis. METHODS: A rat model of mild VAD compatible with normal gestation was developed. Plasma retinol was determined by reverse phase HPLC in mothers and fetuses. Nephron counting was performed in kidneys of fetuses and pups issued from control and VAD mothers. Metanephroi explanted from 14-day-old fetuses from both groups were cultured in the presence or absence of retinoic acid (RA), and growth and differentiation were assessed. c-ret expression was analyzed from fetuses exposed in utero to VAD or to normal vitamin A status and also in metanephroi grown in culture with or without RA using RT-PCR. RESULTS: The 50% reduction in circulating vitamin A levels induced by vitamin A deprivation in pregnant rats did not affect the overall fetal development. However, the number of nephrons was reduced by 20% in 21-day-old VAD fetuses. The number of nephrons was closely correlated with circulating vitamin A level in both VAD and control fetuses. Metanephroi taken from VAD fetuses developed to a lesser extent in vitro, but their capacity to respond to exogenous retinoic acid was not altered. Finally, we found that the expression of the proto-oncogene c-ret was modulated according to the retinoid environment. CONCLUSION: We conclude that vitamin A supply to the fetus is critical in determining the number of nephrons. Data available thus far on the frequency of mild VAD during pregnancy and on the long-term consequences of inborn nephron deficit highlight the clinical relevance of the present study.


Assuntos
Proteínas de Drosophila , Néfrons/anormalidades , Deficiência de Vitamina A/complicações , Animais , Feminino , Gravidez , Proteínas Proto-Oncogênicas/genética , Proteínas Proto-Oncogênicas c-ret , RNA Mensageiro/análise , Ratos , Ratos Sprague-Dawley , Receptores Proteína Tirosina Quinases/genética , Vitamina A/sangue
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