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1.
2.
Arterioscler Thromb Vasc Biol ; 41(9): e427-e439, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-34261328

RESUMO

Objective: Atheromatous fibrous caps are produced by smooth muscle cells (SMCs) that are recruited to the subendothelial space. We tested whether the recruitment mechanisms are the same as in embryonic artery development, which relies prominently on Notch signaling to form the subendothelial medial SMC layers. Approach and Results: Notch elements were expressed in regions of fibrous cap in human and mouse plaques. To assess the causal role of Notch signaling in cap formation, we studied atherosclerosis in mice where the Notch pathway was inactivated in SMCs by conditional knockout of the essential effector transcription factor RBPJ (recombination signal-binding protein for immunoglobulin kappa J region). The recruitment of cap SMCs was significantly reduced without major effects on plaque size. Lineage tracing revealed the accumulation of SMC-derived plaque cells in the cap region was unaltered but that Notch-defective cells failed to re-acquire the SMC phenotype in the cap. Conversely, to analyze whether the loss of Notch signaling is required for SMC-derived cells to accumulate in atherogenesis, we studied atherosclerosis in mice with constitutive activation of Notch signaling in SMCs achieved by conditional expression of the Notch intracellular domain. Forced Notch signaling inhibited the ability of medial SMCs to contribute to plaque cells, including both cap SMCs and osteochondrogenic cells, and significantly reduced atherosclerosis development. Conclusions: Sequential loss and gain of Notch signaling is needed to build the cap SMC population. The shared mechanisms with embryonic arterial media assembly suggest that the cap forms as a neo-media that restores the connection between endothelium and subendothelial SMCs, transiently disrupted in early atherogenesis.


Assuntos
Aterosclerose/metabolismo , Músculo Liso Vascular/metabolismo , Miócitos de Músculo Liso/metabolismo , Placa Aterosclerótica , Receptores Notch/metabolismo , Túnica Média/metabolismo , Actinas/genética , Actinas/metabolismo , Animais , Artérias/metabolismo , Artérias/patologia , Aterosclerose/genética , Aterosclerose/patologia , Linhagem da Célula , Células Cultivadas , Progressão da Doença , Fibrose , Humanos , Proteína de Ligação a Sequências Sinal de Recombinação J de Imunoglobina/genética , Proteína de Ligação a Sequências Sinal de Recombinação J de Imunoglobina/metabolismo , Proteína Jagged-1/genética , Proteína Jagged-1/metabolismo , Masculino , Camundongos Endogâmicos C57BL , Camundongos Knockout , Músculo Liso Vascular/patologia , Miócitos de Músculo Liso/patologia , Fenótipo , Ratos , Receptores Notch/genética , Transdução de Sinais , Túnica Média/patologia
3.
Cell Death Dis ; 12(8): 729, 2021 07 22.
Artigo em Inglês | MEDLINE | ID: mdl-34294700

RESUMO

Bone morphogenetic protein (Bmp) signaling is critical for organismal development and homeostasis. To elucidate Bmp2 function in the vascular/hematopoietic lineages we generated a new transgenic mouse line in which ectopic Bmp2 expression is controlled by the Tie2 promoter. Tie2CRE/+;Bmp2tg/tg mice develop aortic valve dysfunction postnatally, accompanied by pre-calcific lesion formation in valve leaflets. Remarkably, Tie2CRE/+;Bmp2tg/tg mice develop extensive soft tissue bone formation typical of acquired forms of heterotopic ossification (HO) and genetic bone disorders, such as Fibrodysplasia Ossificans Progressiva (FOP). Ectopic ossification in Tie2CRE/+;Bmp2tg/tg transgenic animals is accompanied by increased bone marrow hematopoietic, fibroblast and osteoblast precursors and circulating pro-inflammatory cells. Transplanting wild-type bone marrow hematopoietic stem cells into lethally irradiated Tie2CRE/+;Bmp2tg/tg mice significantly delays HO onset but does not prevent it. Moreover, transplanting Bmp2-transgenic bone marrow into wild-type recipients does not result in HO, but hematopoietic progenitors contribute to inflammation and ectopic bone marrow colonization rather than to endochondral ossification. Conversely, aberrant Bmp2 signaling activity is associated with fibroblast accumulation, skeletal muscle fiber damage, and expansion of a Tie2+ fibro-adipogenic precursor cell population, suggesting that ectopic bone derives from a skeletal muscle resident osteoprogenitor cell origin. Thus, Tie2CRE/+;Bmp2tg/tg mice recapitulate HO pathophysiology, and might represent a useful model to investigate therapies seeking to mitigate disorders associated with aberrant extra-skeletal bone formation.

4.
Physiol Genomics ; 52(12): 563-574, 2020 12 01.
Artigo em Inglês | MEDLINE | ID: mdl-33044885

RESUMO

Calcific aortic valve disease (CAVD) is a significant cause of illness and death worldwide. Identification of early predictive markers could help optimize patient management. RNA-sequencing was carried out on human fetal aortic valves at gestational weeks 9, 13, and 22 and on a case-control study with adult noncalcified and calcified bicuspid and tricuspid aortic valves. In dimension reduction and clustering analyses, diseased valves tended to cluster with fetal valves at week 9 rather than normal adult valves, suggesting that part of the disease program might be due to reiterated developmental processes. The analysis of groups of coregulated genes revealed predominant immune-metabolic signatures, including innate and adaptive immune responses involving lymphocyte T-cell metabolic adaptation. Cytokine and chemokine signaling, cell migration, and proliferation were all increased in CAVD, whereas oxidative phosphorylation and protein translation were decreased. Discrete immune-metabolic gene signatures were present at fetal stages and increased in adult controls, suggesting that these processes intensify throughout life and heighten in disease. Cellular stress response and neurodegeneration gene signatures were aberrantly expressed in CAVD, pointing to a mechanistic link between chronic inflammation and biological aging. Comparison of the valve RNA-sequencing data set with a case-control study of whole blood transcriptomes from asymptomatic individuals with early aortic valve calcification identified a highly predictive gene signature of CAVD and of moderate aortic valve calcification in overtly healthy individuals. These data deepen and broaden our understanding of the molecular basis of CAVD and identify a peripheral blood gene signature for the early detection of aortic valve calcification.

5.
Elife ; 82019 12 04.
Artigo em Inglês | MEDLINE | ID: mdl-31789590

RESUMO

Coronaries are essential for myocardial growth and heart function. Notch is crucial for mouse embryonic angiogenesis, but its role in coronary development remains uncertain. We show Jag1, Dll4 and activated Notch1 receptor expression in sinus venosus (SV) endocardium. Endocardial Jag1 removal blocks SV capillary sprouting, while Dll4 inactivation stimulates excessive capillary growth, suggesting that ligand antagonism regulates coronary primary plexus formation. Later endothelial ligand removal, or forced expression of Dll4 or the glycosyltransferase Mfng, blocks coronary plexus remodeling, arterial differentiation, and perivascular cell maturation. Endocardial deletion of Efnb2 phenocopies the coronary arterial defects of Notch mutants. Angiogenic rescue experiments in ventricular explants, or in primary human endothelial cells, indicate that EphrinB2 is a critical effector of antagonistic Dll4 and Jag1 functions in arterial morphogenesis. Thus, coronary arterial precursors are specified in the SV prior to primary coronary plexus formation and subsequent arterial differentiation depends on a Dll4-Jag1-EphrinB2 signaling cascade.


Assuntos
Vasos Coronários/crescimento & desenvolvimento , Vasos Coronários/metabolismo , Efrina-B2/metabolismo , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Proteína Jagged-1/metabolismo , Proteínas de Membrana/metabolismo , Transdução de Sinais , Animais , Endocárdio/metabolismo , Endotélio Vascular/metabolismo , Ventrículos do Coração/crescimento & desenvolvimento , Ventrículos do Coração/metabolismo , Células Endoteliais da Veia Umbilical Humana/metabolismo , Humanos , Hipóxia/metabolismo , Hipóxia/fisiopatologia , Ligantes , Camundongos , Morfogênese , Mutação/genética , Fatores de Transcrição NFATC/metabolismo , Neovascularização Fisiológica , Receptores Notch/metabolismo , Estresse Fisiológico , Transcriptoma/genética , Remodelação Vascular
6.
Nat Rev Cardiol ; 15(11): 685-704, 2018 11.
Artigo em Inglês | MEDLINE | ID: mdl-30287945

RESUMO

Cardiogenesis is a complex developmental process involving multiple overlapping stages of cell fate specification, proliferation, differentiation, and morphogenesis. Precise spatiotemporal coordination between the different cardiogenic processes is ensured by intercellular signalling crosstalk and tissue-tissue interactions. Notch is an intercellular signalling pathway crucial for cell fate decisions during multicellular organismal development and is aptly positioned to coordinate the complex signalling crosstalk required for progressive cell lineage restriction during cardiogenesis. In this Review, we describe the role of Notch signalling and the crosstalk with other signalling pathways during the differentiation and patterning of the different cardiac tissues and in cardiac valve and ventricular chamber development. We examine how perturbation of Notch signalling activity is linked to congenital heart diseases affecting the neonate and adult, and discuss studies that shed light on the role of Notch signalling in heart regeneration and repair after injury.


Assuntos
Cardiopatias/metabolismo , Valvas Cardíacas/metabolismo , Ventrículos do Coração/metabolismo , Miócitos Cardíacos/metabolismo , Receptor Cross-Talk , Receptores Notch/metabolismo , Regeneração , Transdução de Sinais , Animais , Animais Geneticamente Modificados , Diferenciação Celular , Linhagem da Célula , Proliferação de Células , Coração Fetal/crescimento & desenvolvimento , Coração Fetal/metabolismo , Cardiopatias/patologia , Cardiopatias/fisiopatologia , Valvas Cardíacas/patologia , Valvas Cardíacas/fisiopatologia , Ventrículos do Coração/patologia , Ventrículos do Coração/fisiopatologia , Humanos , Modelos Animais , Miócitos Cardíacos/patologia , Organogênese , Peixe-Zebra/genética , Peixe-Zebra/metabolismo
7.
Elife ; 72018 06 29.
Artigo em Inglês | MEDLINE | ID: mdl-29956664

RESUMO

Abnormalities of the arterial valve leaflets, predominantly bicuspid aortic valve, are the commonest congenital malformations. Although many studies have investigated the development of the arterial valves, it has been assumed that, as with the atrioventricular valves, endocardial to mesenchymal transition (EndMT) is the predominant mechanism. We show that arterial is distinctly different from atrioventricular valve formation. Whilst the four septal valve leaflets are dominated by NCC and EndMT-derived cells, the intercalated leaflets differentiate directly from Tnnt2-Cre+/Isl1+ progenitors in the outflow wall, via a Notch-Jag dependent mechanism. Further, when this novel group of progenitors are disrupted, development of the intercalated leaflets is disrupted, resulting in leaflet dysplasia and bicuspid valves without raphe, most commonly affecting the aortic valve. This study thus overturns the dogma that heart valves are formed principally by EndMT, identifies a new source of valve interstitial cells, and provides a novel mechanism for causation of bicuspid aortic valves without raphe.


Assuntos
Valva Aórtica/anormalidades , Células Epiteliais/patologia , Doenças das Valvas Cardíacas/patologia , Proteína Jagged-1/genética , Miócitos de Músculo Liso/patologia , Receptor Notch1/genética , Células-Tronco/patologia , Animais , Valva Aórtica/metabolismo , Valva Aórtica/patologia , Doença da Válvula Aórtica Bicúspide , Biomarcadores/metabolismo , Diferenciação Celular , Linhagem da Célula/genética , Rastreamento de Células/métodos , Embrião de Mamíferos , Células Epiteliais/metabolismo , Expressão Gênica , Doenças das Valvas Cardíacas/genética , Doenças das Valvas Cardíacas/metabolismo , Humanos , Integrases/genética , Integrases/metabolismo , Proteína Jagged-1/metabolismo , Proteínas com Homeodomínio LIM/genética , Proteínas com Homeodomínio LIM/metabolismo , Camundongos , Camundongos Transgênicos , Miócitos de Músculo Liso/metabolismo , Receptor Notch1/metabolismo , Células-Tronco/metabolismo , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Troponina T/genética , Troponina T/metabolismo
8.
Cardiovasc Res ; 112(2): 568-580, 2016 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-27496872

RESUMO

Aim: To determine the role of NOTCH during the arterial injury response and the subsequent chronic arterial-wall inflammation underlying atherosclerosis. Methods and results: We have generated a mouse model of endothelial-specific (Cdh5-driven) depletion of the Notch effector recombination signal binding protein for immunoglobulin kappa J region (RBPJ) [(ApoE-/-); homozygous RBPJk conditional mice (RBPJflox/flox); Cadherin 5-CreERT, tamoxifen inducible driver mice (Cdh5-CreERT)]. Endothelial-specific deletion of RBPJ or systemic deletion of Notch1 in athero-susceptible ApoE-/- mice fed a high-cholesterol diet for 6 weeks resulted in reduced atherosclerosis in the aortic arch and sinus. Intravital microscopy revealed decreased leucocyte rolling on the endothelium of ApoE-/-; RBPJflox/flox; Cdh5-CreERT mice, correlating with a lowered content of leucocytes and macrophages in the vascular wall. Transcriptome analysis revealed down-regulation of proinflammatory and endothelial activation pathways in atherosclerotic tissue of RBPJ-mutant mice. During normal Notch activation, Jagged1 signalling up-regulation in endothelial cells promotes nuclear translocation of the Notch1 intracellular domain (N1ICD) and its physical interaction with nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB). This N1ICD-NF-κB interaction is required for reciprocal transactivation of target genes, including vascular cell adhesion molecule-1. Conclusions: Notch signalling pathway inactivation decreases leucocyte rolling, thereby preventing endothelial dysfunction and vascular inflammation. Attenuation of Notch signalling might provide a treatment strategy for atherosclerosis.

9.
Circ Res ; 118(10): 1480-97, 2016 05 13.
Artigo em Inglês | MEDLINE | ID: mdl-27056911

RESUMO

RATIONALE: The Notch signaling pathway is crucial for primitive cardiac valve formation by epithelial-mesenchymal transition, and NOTCH1 mutations cause bicuspid aortic valve; however, the temporal requirement for the various Notch ligands and receptors during valve ontogeny is poorly understood. OBJECTIVE: The aim of this study is to determine the functional specificity of Notch in valve development. METHODS AND RESULTS: Using cardiac-specific conditional targeted mutant mice, we find that endothelial/endocardial deletion of Mib1-Dll4-Notch1 signaling, possibly favored by Manic-Fringe, is specifically required for cardiac epithelial-mesenchymal transition. Mice lacking endocardial Jag1, Notch1, or RBPJ displayed enlarged valve cusps, bicuspid aortic valve, and septal defects, indicating that endocardial Jag1 to Notch1 signaling is required for post-epithelial-mesenchymal transition valvulogenesis. Valve dysmorphology was associated with increased mesenchyme proliferation, indicating that Jag1-Notch1 signaling restricts mesenchyme cell proliferation non-cell autonomously. Gene profiling revealed upregulated Bmp signaling in Jag1-mutant valves, providing a molecular basis for the hyperproliferative phenotype. Significantly, the negative regulator of mesenchyme proliferation, Hbegf, was markedly reduced in Jag1-mutant valves. Hbegf expression in embryonic endocardial cells could be readily activated through a RBPJ-binding site, identifying Hbegf as an endocardial Notch target. Accordingly, addition of soluble heparin-binding EGF-like growth factor to Jag1-mutant outflow tract explant cultures rescued the hyperproliferative phenotype. CONCLUSIONS: During cardiac valve formation, Dll4-Notch1 signaling leads to epithelial-mesenchymal transition and cushion formation. Jag1-Notch1 signaling subsequently restrains Bmp-mediated valve mesenchyme proliferation by sustaining Hbegf-EGF receptor signaling. Our studies identify a mechanism of signaling cross talk during valve morphogenesis involved in the origin of congenital heart defects associated with reduced NOTCH function.


Assuntos
Valva Mitral/metabolismo , Morfogênese , Receptor Notch1/genética , Transdução de Sinais , Proteínas Adaptadoras de Transdução de Sinal , Animais , Proteínas de Ligação ao Cálcio , Transição Epitelial-Mesenquimal , Receptores ErbB/metabolismo , Fator de Crescimento Semelhante a EGF de Ligação à Heparina/metabolismo , Proteína de Ligação a Sequências Sinal de Recombinação J de Imunoglobina/genética , Proteína de Ligação a Sequências Sinal de Recombinação J de Imunoglobina/metabolismo , Peptídeos e Proteínas de Sinalização Intracelular/genética , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Proteína Jagged-1/genética , Proteína Jagged-1/metabolismo , Proteínas de Membrana/genética , Proteínas de Membrana/metabolismo , Camundongos , Valva Mitral/anormalidades , Valva Mitral/embriologia , Receptor Notch1/metabolismo , Regulação para Cima
10.
Circ Res ; 118(1): e1-e18, 2016 Jan 08.
Artigo em Inglês | MEDLINE | ID: mdl-26635389

RESUMO

The Notch signaling pathway is an ancient and highly conserved signaling pathway that controls cell fate specification and tissue patterning in the embryo and in the adult. Region-specific endocardial Notch activity regulates heart morphogenesis through the interaction with multiple myocardial-, epicardial-, and neural crest-derived signals. Mutations in NOTCH signaling elements cause congenital heart disease in humans and mice, demonstrating its essential role in cardiac development. Studies in model systems have provided mechanistic understanding of Notch function in cardiac development, congenital heart disease, and heart regeneration. Notch patterns the embryonic endocardium into prospective territories for valve and chamber formation, and later regulates the signaling processes leading to outflow tract and valve morphogenesis and ventricular trabeculae compaction. Alterations in NOTCH signaling in the endocardium result in congenital structural malformations that can lead to disease in the neonate and adult heart.


Assuntos
Endocárdio/crescimento & desenvolvimento , Endocárdio/metabolismo , Cardiopatias/metabolismo , Receptores Notch/metabolismo , Transdução de Sinais/fisiologia , Animais , Endocárdio/patologia , Cardiopatias Congênitas/metabolismo , Cardiopatias Congênitas/patologia , Cardiopatias/patologia , Humanos
11.
Cold Spring Harb Perspect Med ; 4(11): a013912, 2014 Nov 03.
Artigo em Inglês | MEDLINE | ID: mdl-25368013

RESUMO

Cardiac valve disease is a significant cause of ill health and death worldwide, and valve replacement remains one of the most common cardiac interventions in high-income economies. Despite major advances in surgical treatment, long-term therapy remains inadequate because none of the current valve substitutes have the potential for remodeling, regeneration, and growth of native structures. Valve development is coordinated by a complex interplay of signaling pathways and environmental cues that cause disease when perturbed. Cardiac valves develop from endocardial cushions that become populated by valve precursor mesenchyme formed by an epithelial-mesenchymal transition (EMT). The mesenchymal precursors, subsequently, undergo directed growth, characterized by cellular compartmentalization and layering of a structured extracellular matrix (ECM). Knowledge gained from research into the development of cardiac valves is driving exploration into valve biomechanics and tissue engineering directed at creating novel valve substitutes endowed with native form and function.


Assuntos
Próteses Valvulares Cardíacas , Valvas Cardíacas/embriologia , Animais , Matriz Extracelular/fisiologia , Valvas Cardíacas/anatomia & histologia , Valvas Cardíacas/citologia , Humanos , Morfogênese/fisiologia , Engenharia Tecidual , Tecidos Suporte
12.
Brief Funct Genomics ; 13(1): 15-27, 2014 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-24106100

RESUMO

The Notch signalling pathway plays crucial roles in cardiac development and postnatal cardiac homoeostasis. Gain- and loss-of-function approaches indicate that Notch promotes or inhibits cardiogenesis in a stage-dependent manner. However, the molecular mechanisms are poorly defined because many downstream effectors remain to be identified. Genome-scale analyses are shedding light on the genes that are regulated by Notch signalling and the mechanisms underlying this regulation. We review the functional data that implicates Notch in cardiac morphogenetic processes and expression profiling studies that enlighten the regulatory networks behind them. A recurring theme is that Notch cross-talks reiteratively with other key signalling pathways including Wnt and Bmp to coordinate cell and tissue interactions during cardiogenesis.


Assuntos
Genômica/métodos , Cardiopatias Congênitas/genética , Coração/crescimento & desenvolvimento , Receptores Notch/metabolismo , Transdução de Sinais/genética , Animais , Padronização Corporal/genética , Humanos
13.
Nat Med ; 19(2): 193-201, 2013 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-23314057

RESUMO

Left ventricular noncompaction (LVNC) causes prominent ventricular trabeculations and reduces cardiac systolic function. The clinical presentation of LVNC ranges from asymptomatic to heart failure. We show that germline mutations in human MIB1 (mindbomb homolog 1), which encodes an E3 ubiquitin ligase that promotes endocytosis of the NOTCH ligands DELTA and JAGGED, cause LVNC in autosomal-dominant pedigrees, with affected individuals showing reduced NOTCH1 activity and reduced expression of target genes. Functional studies in cells and zebrafish embryos and in silico modeling indicate that MIB1 functions as a dimer, which is disrupted by the human mutations. Targeted inactivation of Mib1 in mouse myocardium causes LVNC, a phenotype mimicked by inactivation of myocardial Jagged1 or endocardial Notch1. Myocardial Mib1 mutants show reduced ventricular Notch1 activity, expansion of compact myocardium to proliferative, immature trabeculae and abnormal expression of cardiac development and disease genes. These results implicate NOTCH signaling in LVNC and indicate that MIB1 mutations arrest chamber myocardium development, preventing trabecular maturation and compaction.


Assuntos
Cardiomiopatias/etiologia , Ventrículos do Coração , Mutação , Receptores Notch/fisiologia , Transdução de Sinais/fisiologia , Ubiquitina-Proteína Ligases/genética , Sequência de Aminoácidos , Animais , Cardiomiopatias/genética , Feminino , Células HEK293 , Coração/embriologia , Ventrículos do Coração/embriologia , Humanos , Masculino , Camundongos , Dados de Sequência Molecular , Multimerização Proteica , Ubiquitina-Proteína Ligases/fisiologia , Peixe-Zebra
14.
Birth Defects Res A Clin Mol Teratol ; 91(6): 449-59, 2011 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-21563298

RESUMO

The Notch pathway is an intercellular signaling mechanism involved in multiple cell-to-cell communication processes that regulate cell fate specification, differentiation, and tissue patterning during embryogenesis and adulthood. Functional studies in the mouse have shown that a Hey-Bmp2 regulatory circuit restricts Bmp2 expression to presumptive valve myocardium (atrioventricular canal and outflow tract). Likewise, a Notch-Hey-Bmp2 axis represses Bmp2 in the endocardium. During cardiac valve formation, endocardial Notch signaling activates the epithelial-mesenchyme transition (EMT) that will give rise to the cardiac valve primordia. During this process, Notch integrates with myocardially derived signals (Bmp2 or Bmp4) to promote, via Snail1/2 activation a complete, invasive EMT in presumptive valve tissue. In humans, mutations in Notch signaling components are associated with several congenital disorders involving malformed valves, aortic arch, and defective chamber septation. Data suggest that the same embryonic Notch-Hey-Bmp2 regulatory axis is active in the adult valve. This review examines the experimental evidence supporting a role for Notch in heart valve development and homeostasis, and how altered Notch signaling may lead to valve disease in the newborn and adult.


Assuntos
Cardiopatias Congênitas/metabolismo , Valvas Cardíacas/embriologia , Receptores Notch/metabolismo , Transdução de Sinais , Transição Epitelial-Mesenquimal/genética , Regulação da Expressão Gênica no Desenvolvimento , Cardiopatias Congênitas/genética , Valvas Cardíacas/patologia , Humanos , Receptores Notch/genética
15.
Arterioscler Thromb Vasc Biol ; 31(7): 1580-8, 2011 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-21493891

RESUMO

OBJECTIVE: Calcific aortic valve disease is similar to atherosclerosis in that both diseases result from chronic inflammation and endothelial dysfunction. Heterozygous NOTCH1 mutations have been associated to calcific aortic disease and a bicuspid aortic valve. We investigated whether mice with genetic inactivation of the Notch signaling pathway are prone to develop valve disease when exposed to a predisposing diet. METHODS AND RESULTS: Using Doppler echocardiography, histology, immunohistochemistry, quantitative gene expression analysis, and cell culture assays, we examined the effect of a hypercholesterolemic diet supplemented with vitamin D on mice heterozygous for null mutations in the Notch1 receptor or the effector transcription factor gene RBPJk. After 16 weeks on the hyperlipidemic diet, calcific aortic disease was detected in heterozygous RBPJk mice. Analysis of valve leaflets revealed macrophage infiltration, enhanced collagen deposition, proosteogenic protein expression, and calcification. Heterozygous null Notch1 mice displayed milder histopathologic changes and did not develop any significant hemodynamic disturbance. Valvular disease correlated with reduced expression of the Notch target gene Hey1 in valves of RBPJk heterozygous mice fed the hyperlipidemic diet. Consistent with the in vivo data, Notch signaling inhibition in porcine valve interstitial cells led to downregulation of HEY1 transcription, activation of osteogenic markers, and increased calcified nodule formation. CONCLUSIONS: We show that Notch signaling disruption via RBPJk heterozygous inactivation results in aortic valve disease. Notch1 heterozygous mice do not show functional impairment, suggesting that additional Notch receptors may be involved in aortic valve homeostasis and disease. Our data establish a genetic mouse model of calcific aortic valve disease and may help to identify a patient population with reduced valvular NOTCH signaling at risk for developing this disease.


Assuntos
Valva Aórtica/metabolismo , Calcinose/etiologia , Haploinsuficiência , Doenças das Valvas Cardíacas/etiologia , Hipercolesterolemia/complicações , Proteína de Ligação a Sequências Sinal de Recombinação J de Imunoglobina/deficiência , Receptor Notch1/deficiência , Transdução de Sinais , Análise de Variância , Animais , Valva Aórtica/patologia , Valva Aórtica/fisiopatologia , Calcinose/genética , Calcinose/metabolismo , Calcinose/patologia , Calcinose/fisiopatologia , Proteínas de Ciclo Celular/genética , Proteínas de Ciclo Celular/metabolismo , Células Cultivadas , Colesterol na Dieta , Modelos Animais de Doenças , Ecocardiografia Doppler , Fibrose , Regulação da Expressão Gênica , Genótipo , Doenças das Valvas Cardíacas/genética , Doenças das Valvas Cardíacas/metabolismo , Doenças das Valvas Cardíacas/patologia , Doenças das Valvas Cardíacas/fisiopatologia , Hemodinâmica , Heterozigoto , Hipercolesterolemia/etiologia , Hipercolesterolemia/genética , Hipercolesterolemia/metabolismo , Hipercolesterolemia/patologia , Hipercolesterolemia/fisiopatologia , Proteína de Ligação a Sequências Sinal de Recombinação J de Imunoglobina/genética , Imuno-Histoquímica , Camundongos , Camundongos Knockout , Osteogênese/genética , Fenótipo , Receptor Notch1/genética , Volume Sistólico , Suínos , Função Ventricular , Vitamina D
16.
Circ Res ; 108(7): 824-36, 2011 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-21311046

RESUMO

RATIONALE: The proepicardium is a transient structure comprising epicardial progenitor cells located at the posterior limit of the embryonic cardiac inflow. A network of signals regulates proepicardial cell fate and defines myocardial and nonmyocardial domains at the venous pole of the heart. During cardiac development, epicardial-derived cells also contribute to coronary vessel morphogenesis. OBJECTIVE: To study Notch function during proepicardium development and coronary vessel formation in the mouse. METHODS AND RESULTS: Using in situ hybridization, RT-PCR, and immunohistochemistry, we find that Notch pathway elements are differentially activated throughout the proepicardial-epicardial-coronary transition. Analysis of RBPJk-targeted embryos indicates that Notch ablation causes ectopic procardiogenic signaling in the proepicardium that in turn promotes myocardial differentiation in adjacent mesodermal progenitors, resulting in a premature muscularization of the sinus venosus horns. Epicardium-specific Notch1 ablation using a Wt1-Cre driver line disrupts coronary artery differentiation, reduces myocardium wall thickness and myocyte proliferation, and reduces Raldh2 expression. Ectopic Notch1 activation disrupts epicardium development and causes thinning of ventricular walls. CONCLUSIONS: Epicardial Notch modulates cell differentiation in the proepicardium and adjacent pericardial mesoderm. Notch1 is later required for arterial endothelium commitment and differentiation and for vessel wall maturation during coronary vessel development and myocardium growth.


Assuntos
Circulação Sanguínea/fisiologia , Vasos Coronários/embriologia , Morfogênese/fisiologia , Pericárdio/embriologia , Receptores Notch/fisiologia , Transdução de Sinais/fisiologia , Aldeído Oxirredutases/genética , Aldeído Oxirredutases/fisiologia , Animais , Proteína Morfogenética Óssea 2/genética , Proteína Morfogenética Óssea 2/fisiologia , Diferenciação Celular/fisiologia , Proliferação de Células , Vasos Coronários/citologia , Proteína de Ligação a Sequências Sinal de Recombinação J de Imunoglobina/genética , Proteína de Ligação a Sequências Sinal de Recombinação J de Imunoglobina/fisiologia , Camundongos , Camundongos Endogâmicos , Camundongos Transgênicos , Modelos Animais , Mutação , Pericárdio/citologia , Receptor Notch1/genética , Receptor Notch1/fisiologia , Receptores Notch/genética
17.
Curr Top Dev Biol ; 92: 333-65, 2010.
Artigo em Inglês | MEDLINE | ID: mdl-20816401

RESUMO

The Notch-signaling pathway is involved in multiple processes during vertebrate cardiac development. Cardiomyocyte differentiation, patterning of the different cardiac regions, valve development, ventricular trabeculation, and outflow tract development have all been shown to depend on the activity of specific Notch-signaling elements. From these studies, it becomes obvious that Notch regulates in a cell autonomous or non-cell autonomous manner different signaling pathways, pointing to a role for Notch as a signal coordinator during cardiogenesis. While most of the research has concentrated on Notch signaling in the myocardium, the importance of Notch activity in the cardiac endothelium (endocardium) must not be overlooked. Endocardial Notch activity is crucial for valve and ventricular trabeculae development, two processes that illustrate the role of Notch as a signal coordinator. The importance of Notch signaling in human disease is evident from the discovery that many mutations in components of this pathway segregate in several inherited and acquired disorders. This reflects the fundamental roles that Notch performs during cardiac ontogeny. This review examines the experimental evidence supporting a role for Notch in cardiac development and adult heart homeostasis, and how dysregulated Notch signaling may lead to cardiac disease in the newborn and in the adult.


Assuntos
Cardiopatias/fisiopatologia , Coração/fisiologia , Receptores Notch/metabolismo , Transdução de Sinais , Animais , Humanos
18.
Interdiscip Top Gerontol ; 35: 159-75, 2007.
Artigo em Inglês | MEDLINE | ID: mdl-17063038

RESUMO

Alzheimer's disease (AD) is a rapidly growing public health concern with potentially devastating effects. Presently, there are no known cures or effective preventive strategies. While genetic factors are relevant in early-onset cases, they appear to play less of a role in late-onset sporadic AD cases, the most common form of AD. Due to the fact that the disease typically strikes very late in life, delaying symptoms could be as good as a cure for many people. For example, it is now widely accepted that if the onset of the disease could be delayed by even 5 years, the incidence could be cut in half. Both clinical and epidemiological evidence suggests that modification of lifestyle factors such as nutrition may prove crucial to AD management given the mounting experimental evidence suggesting that brain cells are remarkably responsive to "what somebody is doing". Among other nongenetic factors influencing AD, recent studies strongly support the evidence that caloric intake may play a role in the relative risk for AD clinical dementia. Indeed, the effect of diet in AD has been an area of research that has produced promising results, at least experimentally. Most importantly, as mechanistic pathways are defined and their biochemical functions scrutinized, the evidence supporting a direct link between nutrition and AD neuropathology continues to grow. Our work, as well as that of others, has recently resulted in the development of experimental dietary regimens that might promote, attenuate or even reverse features of AD. Most remarkably, while we found that high caloric intake based on saturated fat promotes AD type Beta-amyloidosis, conversely we found that dietary restriction based on reduced carbohydrate intake is able to prevent it. This evidence is very exciting and is, in part, consistent with current epidemiological studies suggesting that obesity and diabetes are associated with a >4-fold increased risk of developing AD. The clarification of the mechanisms through which dietary restriction may beneficially influence AD neuropathology and the eventual discovery of future "mimetics" capable of anti-Beta-amyloidogenic activity will help in the development of "lifestyle therapeutic strategies" in AD and possibly other neurodegenerative disorders.


Assuntos
Doença de Alzheimer/metabolismo , Restrição Calórica , Idade de Início , Doença de Alzheimer/fisiopatologia , Doença de Alzheimer/terapia , Progressão da Doença , Humanos , Estilo de Vida , Medição de Risco , Fatores de Risco
19.
J Biol Chem ; 281(31): 21745-21754, 2006 Aug 04.
Artigo em Inglês | MEDLINE | ID: mdl-16751189

RESUMO

Nicotinamide adenine dinucleotide (NAD)+-dependent sirtuins have been identified to be key regulators in the lifespan extending effects of calorie restriction (CR) in a number of species. In this study we report for the first time that promotion of the NAD+-dependent sirtuin, SIRT1-mediated deacetylase activity, may be a mechanism by which CR influences Alzheimer disease (AD)-type amyloid neuropathology. Most importantly, we report that the predicted attenuation of beta-amyloid content in the brain during CR can be reproduced in mouse neurons in vitro by manipulating cellular SIRT1 expression/activity through mechanisms involving the regulation of the serine/threonine Rho kinase ROCK1, known in part for its role in the inhibition of the non-amyloidogenic alpha-secretase processing of the amyloid precursor protein. Conversely, we found that the expression of constitutively active ROCK1 in vitro cultures significantly prevented SIRT1-mediated response, suggesting that alpha-secretase activity is required for SIRT1-mediated prevention of AD-type amyloid neuropathology. Consistently we found that the expression of exogenous human (h) SIRT1 in the brain of hSIRT1 transgenics also resulted in decreased ROCK1 expression and elevated alpha-secretase activity in vivo. These results demonstrate for the first time a role for SIRT1 activation in the brain as a novel mechanism through which CR may influence AD amyloid neuropathology. The study provides a potentially novel pharmacological strategy for AD prevention and/or treatment.


Assuntos
Doença de Alzheimer/dietoterapia , Restrição Calórica , Neurônios/enzimologia , Sirtuínas/metabolismo , Doença de Alzheimer/prevenção & controle , Amiloide/análise , Secretases da Proteína Precursora do Amiloide , Animais , Ácido Aspártico Endopeptidases , Endopeptidases/metabolismo , Ativação Enzimática , Feminino , Humanos , Peptídeos e Proteínas de Sinalização Intracelular/genética , Peptídeos e Proteínas de Sinalização Intracelular/fisiologia , Camundongos , Camundongos Endogâmicos , Camundongos Transgênicos , Neurônios/patologia , Proteínas Serina-Treonina Quinases/genética , Proteínas Serina-Treonina Quinases/fisiologia , Sirtuína 1 , Quinases Associadas a rho
20.
BMC Neurosci ; 7: 29, 2006 Apr 03.
Artigo em Inglês | MEDLINE | ID: mdl-16584562

RESUMO

BACKGROUND: The cause of neuronal death in amyotrophic lateral sclerosis (ALS) is uncertain but mitochondrial dysfunction may play an important role. Ketones promote mitochondrial energy production and membrane stabilization. RESULTS: SOD1-G93A transgenic ALS mice were fed a ketogenic diet (KD) based on known formulations for humans. Motor performance, longevity, and motor neuron counts were measured in treated and disease controls. Because mitochondrial dysfunction plays a central role in neuronal cell death in ALS, we also studied the effect that the principal ketone body, D-beta-3 hydroxybutyrate (DBH), has on mitochondrial ATP generation and neuroprotection. Blood ketones were > 3.5 times higher in KD fed animals compared to controls. KD fed mice lost 50% of baseline motor performance 25 days later than disease controls. KD animals weighed 4.6 g more than disease control animals at study endpoint; the interaction between diet and change in weight was significant (p = 0.047). In spinal cord sections obtained at the study endpoint, there were more motor neurons in KD fed animals (p = 0.030). DBH prevented rotenone mediated inhibition of mitochondrial complex I but not malonate inhibition of complex II. Rotenone neurotoxicity in SMI-32 immunopositive motor neurons was also inhibited by DBH. CONCLUSION: This is the first study showing that diet, specifically a KD, alters the progression of the clinical and biological manifestations of the G93A SOD1 transgenic mouse model of ALS. These effects may be due to the ability of ketone bodies to promote ATP synthesis and bypass inhibition of complex I in the mitochondrial respiratory chain.


Assuntos
Esclerose Amiotrófica Lateral/dietoterapia , Esclerose Amiotrófica Lateral/metabolismo , Dieta , Corpos Cetônicos/biossíntese , Esclerose Amiotrófica Lateral/genética , Esclerose Amiotrófica Lateral/fisiopatologia , Animais , Sobrevivência Celular/efeitos dos fármacos , Progressão da Doença , Hidroxibutirato Desidrogenase/farmacologia , Corpos Cetônicos/sangue , Masculino , Camundongos , Camundongos Transgênicos , Mitocôndrias/efeitos dos fármacos , Neurônios Motores/efeitos dos fármacos , Superóxido Dismutase/genética
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