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1.
Mol Ther Nucleic Acids ; 29: 769-786, 2022 Sep 13.
Artigo em Inglês | MEDLINE | ID: mdl-36159592

RESUMO

Satellite cells (SCs), muscle stem cells, display functional heterogeneity, and dramatic changes linked to their regenerative capabilities are associated with muscle-wasting diseases. SC behavior is related to endogenous expression of the myogenic transcription factor MYF5 and the propensity to enter into the cell cycle. Here, we report a role for miR-106b reinforcing MYF5 inhibition and blocking cell proliferation in a subset of highly quiescent SC population. miR-106b down-regulation occurs during SC activation and is required for proper muscle repair. In addition, miR-106b is increased in dystrophic mice, and intramuscular injection of antimiR in injured mdx mice enhances muscle regeneration promoting transcriptional changes involved in skeletal muscle differentiation. miR-106b inhibition promotes the engraftment of human muscle stem cells. Furthermore, miR-106b is also high in human dystrophic muscle stem cells and its inhibition improves intrinsic proliferative defects and increases their myogenic potential. This study demonstrates that miR-106b is an important modulator of SC quiescence, and that miR-106b may be a new target to develop therapeutic strategies to promote muscle regeneration improving the regenerative capabilities of injured dystrophic muscle.

2.
Ann Vasc Surg ; 56: 216-223, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30500645

RESUMO

BACKGROUND: Aortic arch curvature can be straightened by endograft placement. However, different measurement methods with dissimilar follow-up and endografts have been published. The aim of this study was to corroborate, for the first time, the pliability of the Conformable Gore TAG Thoracic Endoprosthesis (W.L. Gore and Associates, Flagstaff, AZ, USA) into the aortic arch, using different image vector analysis. MATERIAL AND METHODS: We, retrospectively, analyzed patients primarily treated for thoracic aortic aneurysms and blunt traumatic aortic injuries by means of a Conformable Gore TAG Thoracic Endoprosthesis endograft proximally sealed into the aortic arch (zones Z1-Z3) in five different Spanish centers, between 2010 and 2017. The preoperative, one-month and six-month postoperative, computed tomography angiographies (CTAs) were obtained, creating accurate 3D center lumen line and external lumen line from the aortic valve to the renal arteries. Three different image analysis methods were used to compare modifications of the aortic curvature: first, segment analysis (angulations of the center lumen line when divided into seven precise segments, examining anterior-posterior, right-left, and cranial-caudal displacement), second, center lumen line analysis (bending of the center lumen line itself in seven definite points), and third, expected behavior (length of the endograft in the external lumen line). Two independent observers performed a blind analysis of all CTAs. Changes between preoperative and postoperative CTAs at one and six months are compared, and differences are viewed between cases sealed proximally (Z1-Z2) and distally (Z3) into the aortic arch. RESULTS: We analyzed 37 cases. At 1- and 6-month follow-ups, minimal changes occurred first in segment analysis (only a slight decrease of -2.0° in the XY plane at 10 cm from the brachiocephalic trunk at six-month follow-up was seen, P = 0.027). Second, center lumen line analysis again only showed negligible aortic curvature straightening (+3.5° at 10 cm from the brachiocephalic trunk at one month, P = 0.006, disappearing at six-month follow-up). Finally, good device length predictability was shown (interclass correlation coefficients: 0.995 and 0.994 at one and six months, P > 0.001). No differences were seen between cases proximally sealed into the proximal and distal aortic arch. CONCLUSIONS: Conformable Gore TAG Thoracic Endoprosthesis thoracic endograft showed a good pliability into the aortic arch and proximal thoracic aorta, with minimal changes in the aortic curvature after endograft placement in the short-term follow-up (up to six months). In addition, final endograft length into outer aortic curvature is highly predictable.


Assuntos
Aorta Torácica/diagnóstico por imagem , Aorta Torácica/cirurgia , Aneurisma da Aorta Torácica/diagnóstico por imagem , Aneurisma da Aorta Torácica/cirurgia , Aortografia/métodos , Implante de Prótese Vascular/instrumentação , Prótese Vascular , Angiografia por Tomografia Computadorizada/métodos , Procedimentos Endovasculares/instrumentação , Interpretação de Imagem Radiográfica Assistida por Computador/métodos , Lesões do Sistema Vascular/diagnóstico por imagem , Lesões do Sistema Vascular/cirurgia , Idoso , Idoso de 80 Anos ou mais , Aorta Torácica/lesões , Aorta Torácica/fisiopatologia , Aneurisma da Aorta Torácica/fisiopatologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Valor Preditivo dos Testes , Desenho de Prótese , Estudos Retrospectivos , Espanha , Fatores de Tempo , Resultado do Tratamento , Remodelação Vascular , Lesões do Sistema Vascular/fisiopatologia
3.
PLoS One ; 12(10): e0185494, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28973039

RESUMO

We aimed to test whether high-intensity high-volume training (HIHVT) swimming would induce more robust signaling than sprint interval training (SIT) swimming within the m. triceps brachii due to lower metabolic and oxidation. Nine well-trained swimmers performed the two training procedures on separate randomized days. Muscle biopsies from m. triceps brachii and blood samples were collected at three different time points: a) before the intervention (pre), b) immediately after the swimming procedures (post) and c) after 3 h of rest (3 h). Hydroperoxides, creatine kinase (CK), and lactate dehydrogenase (LDH) were quantified from blood samples, and peroxisome proliferator-activated receptor γ coactivator 1α (PGC-1α) and the AMPKpTHR172/AMPK ratio were quantified by Western blot analysis. PGC-1α, sirtuin 3 (SIRT3), superoxide-dismutase 2 (SOD2), and vascular endothelial growth factor (VEGF) mRNA levels were also quantified. SIT induced a higher release of LDH (p < 0.01 at all time points) and CK (p < 0.01 at post) than HIHVT, but neither SIT nor HIHVT altered systemic hydroperoxides. Additionally, neither SIRT3 nor SOD2 mRNA levels increased, while PGC-1α transcription increased at 3 h after SIT (p < 0.01) and after HIHVT (p < 0.001). However, PGC-1α protein was higher after HIHVT than after SIT (p < 0.05). Moreover, the AMPKpTHR172/AMPK ratio increased at post after SIT (p < 0.05), whereas this effect was delayed after HIHVT as it increased after 3 h (p < 0.05). In addition, VEGF transcription was higher in response to HIHVT (p < 0.05). In conclusion, SIT induces higher muscular stress than HIHVT without increasing systemic oxidation. In addition, HIHVT may induce more robust oxidative adaptations through PGC-1α and AMPK.


Assuntos
Proteínas Quinases Ativadas por AMP/metabolismo , Músculo Esquelético/fisiologia , Coativador 1-alfa do Receptor gama Ativado por Proliferador de Peroxissomo/metabolismo , Transdução de Sinais , Natação , Antioxidantes/metabolismo , Western Blotting , Frequência Cardíaca , Humanos , Lactatos/sangue , Peroxidação de Lipídeos , Masculino , Músculo Esquelético/metabolismo , Estresse Oxidativo , RNA Mensageiro/genética , Reação em Cadeia da Polimerase em Tempo Real , Transcrição Gênica
4.
Med. clín (Ed. impr.) ; 146(2): 49-54, ene. 2016. tab, graf
Artigo em Espanhol | IBECS | ID: ibc-147760

RESUMO

Fundamento y objetivo: Actualmente no se conoce con exactitud la prevalencia del síndrome postrombótico (SPT) en España. El objetivo principal de este trabajo fue determinar la prevalencia de SPT y los posibles factores pronóstico asociados a su desarrollo y el impacto sobre la calidad de vida. Pacientes y método: Estudio observacional, multicéntrico, de corte trasversal y seguimiento retrospectivo. Se incluyeron pacientes que hubieran sufrido una trombosis venosa profunda (TVP) entre marzo de 2010 y marzo de 2011. En la inclusión, el investigador examinó a los pacientes y cumplimentó la escala Villalta; en función de la puntuación, se distribuyeron en pacientes con SPT (puntuación > 4) y pacientes sin SPT (puntuación ≤ 4). Posteriormente, se recogieron de forma retrospectiva datos de la TVP y factores de riesgo. Se evaluó la calidad de vida de los pacientes. Resultados: Fueron incluidos 511 pacientes con TVP, de los que se excluyeron 7 por no cumplir algún criterio de inclusión/exclusión. La prevalencia de SPT fue del 53%, siendo un 56,2% de carácter leve, un 20,6%, moderado, y un 23,2%, grave. La presencia de factores de riesgo de TVP, como inmovilización, terapia hormonal y obesidad, fue significativamente mayor en pacientes con SPT frente a pacientes sin SPT. No se encontraron diferencias significativas en la localización de TVP. La percepción del paciente sobre su salud fue significativamente peor en presencia de SPT. Conclusiones: La prevalencia de SPT en pacientes con TVP es muy alta. La presencia de factores de riesgo de TVP contribuye a una mayor predisposición a presentar SPT, en un tiempo medio de 2 años (AU)


Background and objective: The prevalence of post-thrombotic syndrome (PTS) in Spain is not known accurately at present. The main objective of this study was to determine the prevalence of PTS and the possible prognostic factors related to its development and impact on quality of life. Patients and method: This was an observational, multicenter, cross-sectional and retrospective study of patients who had suffered a deep vein thrombosis (DVT) between March 2010 and March 2011. The Villalta scale was applied as a standardized assessment of PTS at the enrollment visit. According to the score, distribution was: patients with PTS (score > 4) and patients without PTS (score ≤ 4). Subsequently, DVT data and risk factors were collected retrospectively. The quality of life of patients was evaluated. Results: In total 511 patients with DVT were enrolled, of which 7 patients were excluded as they did not meet the inclusion/exclusion criteria. The prevalence of PTS was 53%, with 56.2% having a mild character, 20.6% moderate, and 23.2% severe. The presence of risk factors for DVT including immobilization, hormonal therapy and obesity was significantly higher in patients with PTS than in patients without PTS. There were not significant differences in the location of the DVT. The perception of patients about their health was significantly worse in patients with DVT. Conclusions: The prevalence of PTS in patients with DVT is very high. The presence of risk factors for DVT clearly contributes to a greater predisposition to suffering PTS in an average time of 2 years (AU)


Assuntos
Humanos , Masculino , Feminino , Síndrome Pós-Trombótica/epidemiologia , Síndrome Pós-Trombótica/prevenção & controle , Trombose Venosa/complicações , Trombose Venosa/epidemiologia , Trombose Venosa/prevenção & controle , Prognóstico , Qualidade de Vida , Estudos Transversais , Fatores de Risco , 28599
5.
Med Clin (Barc) ; 146(2): 49-54, 2016 Jan 15.
Artigo em Espanhol | MEDLINE | ID: mdl-26198362

RESUMO

BACKGROUND AND OBJECTIVE: The prevalence of post-thrombotic syndrome (PTS) in Spain is not known accurately at present. The main objective of this study was to determine the prevalence of PTS and the possible prognostic factors related to its development and impact on quality of life. PATIENTS AND METHOD: This was an observational, multicenter, cross-sectional and retrospective study of patients who had suffered a deep vein thrombosis (DVT) between March 2010 and March 2011. The Villalta scale was applied as a standardized assessment of PTS at the enrollment visit. According to the score, distribution was: patients with PTS (score>4) and patients without PTS (score ≤4). Subsequently, DVT data and risk factors were collected retrospectively. The quality of life of patients was evaluated. RESULTS: In total 511 patients with DVT were enrolled, of which 7 patients were excluded as they did not meet the inclusion/exclusion criteria. The prevalence of PTS was 53%, with 56.2% having a mild character, 20.6% moderate, and 23.2% severe. The presence of risk factors for DVT including immobilization, hormonal therapy and obesity was significantly higher in patients with PTS than in patients without PTS. There were not significant differences in the location of the DVT. The perception of patients about their health was significantly worse in patients with DVT. CONCLUSIONS: The prevalence of PTS in patients with DVT is very high. The presence of risk factors for DVT clearly contributes to a greater predisposition to suffering PTS in an average time of 2 years.


Assuntos
Síndrome Pós-Trombótica/epidemiologia , Trombose Venosa/complicações , Adulto , Idoso , Anticoagulantes/uso terapêutico , Comorbidade , Estudos Transversais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Síndrome Pós-Trombótica/tratamento farmacológico , Síndrome Pós-Trombótica/etiologia , Prevalência , Prognóstico , Qualidade de Vida , Estudos Retrospectivos , Fatores de Risco , Espanha/epidemiologia , Trombose Venosa/tratamento farmacológico
6.
Org Biomol Chem ; 13(45): 11078-86, 2015 Dec 07.
Artigo em Inglês | MEDLINE | ID: mdl-26400105

RESUMO

Cyclooxygenases (COXs) are enzymes that play a vital role in the inflammatory cascade through the generation of prostaglandins. Their over-expression has been implicated in numerous diseases. In particular, over-expression of COX-2 has been shown to be a predictive biomarker for progression of pre-malignant lesions towards invasive cancer in various tissues. This makes the early detection of COX-2 expressing lesions of high clinical relevance. Herein we describe the development of the first self-immolating trigger which targets COXs. We incorporated our trigger design into 2 activatable fluorogenic probes and demonstrated COX-specific activation in vitro. Experimental data revealed probe activation was likely caused by solvent-exposed amino acids on the surface of the COXs. Overall, the probes reported here mark the first step towards developing self-immolating imaging/therapeutic agents targeted to specific COXs.


Assuntos
Aspirina/análogos & derivados , Aspirina/metabolismo , Ciclo-Oxigenase 1/metabolismo , Ciclo-Oxigenase 2/metabolismo , Corantes Fluorescentes/química , Corantes Fluorescentes/metabolismo , Animais , Linhagem Celular , Ciclo-Oxigenase 1/análise , Ciclo-Oxigenase 2/análise , Humanos , Camundongos , Modelos Moleculares , Imagem Óptica , Ovinos , Espectrometria de Fluorescência , Suínos
7.
Proc Natl Acad Sci U S A ; 110(40): 16103-8, 2013 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-24046372

RESUMO

The emergence of resistance to chemotherapy by cancer cells, when combined with metastasis, is the primary driver of mortality in cancer and has proven to be refractory to many efforts. Theory and computer modeling suggest that the rate of emergence of resistance is driven by the strong selective pressure of mutagenic chemotherapy and enhanced by the motility of mutant cells in a chemotherapy gradient to areas of higher drug concentration and lower population competition. To test these models, we constructed a synthetic microecology which superposed a mutagenic doxorubicin gradient across a population of motile, metastatic breast cancer cells (MDA-MB-231). We observed the emergence of MDA-MB-231 cancer cells capable of proliferation at 200 nM doxorubicin in this complex microecology. Individual cell tracking showed both movement of the MDA-MB-231 cancer cells toward higher drug concentrations and proliferation of the cells at the highest doxorubicin concentrations within 72 h, showing the importance of both motility and drug gradients in the emergence of resistance.


Assuntos
Antineoplásicos/metabolismo , Movimento Celular/fisiologia , Resistencia a Medicamentos Antineoplásicos/fisiologia , Evolução Molecular , Neoplasias/fisiopatologia , Linhagem Celular Tumoral , Proliferação de Células , Doxorrubicina , Humanos , Técnicas Analíticas Microfluídicas , Seleção Genética , Fatores de Tempo
8.
Sci Rep ; 3: 1449, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23618955

RESUMO

To investigate the transition from non-cancerous to metastatic from a physical sciences perspective, the Physical Sciences-Oncology Centers (PS-OC) Network performed molecular and biophysical comparative studies of the non-tumorigenic MCF-10A and metastatic MDA-MB-231 breast epithelial cell lines, commonly used as models of cancer metastasis. Experiments were performed in 20 laboratories from 12 PS-OCs. Each laboratory was supplied with identical aliquots and common reagents and culture protocols. Analyses of these measurements revealed dramatic differences in their mechanics, migration, adhesion, oxygen response, and proteomic profiles. Model-based multi-omics approaches identified key differences between these cells' regulatory networks involved in morphology and survival. These results provide a multifaceted description of cellular parameters of two widely used cell lines and demonstrate the value of the PS-OC Network approach for integration of diverse experimental observations to elucidate the phenotypes associated with cancer metastasis.


Assuntos
Biomarcadores Tumorais/metabolismo , Regulação Neoplásica da Expressão Gênica , Modelos Biológicos , Metástase Neoplásica/patologia , Metástase Neoplásica/fisiopatologia , Proteínas de Neoplasias/metabolismo , Linhagem Celular Tumoral , Movimento Celular , Tamanho Celular , Sobrevivência Celular , Simulação por Computador , Humanos
9.
Phys Biol ; 9(6): 065005, 2012 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-23197078

RESUMO

Complex biological systems often display a randomness paralleled in processes studied in fundamental physics. This simple stochasticity emerges owing to the complexity of the system and underlies a fundamental aspect of biology called phenotypic stochasticity. Ongoing stochastic fluctuations in phenotype at the single-unit level can contribute to two emergent population phenotypes. Phenotypic stochasticity not only generates heterogeneity within a cell population, but also allows reversible transitions back and forth between multiple states. This phenotypic interconversion tends to restore a population to a previous composition after that population has been depleted of specific members. We call this tendency homeostatic heterogeneity. These concepts of dynamic heterogeneity can be applied to populations composed of molecules, cells, individuals, etc. Here we discuss the concept that phenotypic stochasticity both underlies the generation of heterogeneity within a cell population and can be used to control population composition, contributing, in particular, to both the ongoing emergence of drug resistance and an opportunity for depleting drug-resistant cells. Using notions of both 'large' and 'small' numbers of biomolecular components, we rationalize our use of Markov processes to model the generation and eradication of drug-resistant cells. Using these insights, we have developed a graphical tool, called a metronomogram, that we propose will allow us to optimize dosing frequencies and total course durations for clinical benefit.


Assuntos
Antineoplásicos/uso terapêutico , Neoplasias/tratamento farmacológico , Neoplasias/genética , Antineoplásicos/farmacologia , Esquema de Medicação , Resistencia a Medicamentos Antineoplásicos , Dosagem de Genes , Humanos , Cadeias de Markov , Modelos Biológicos , Fenótipo , Processos Estocásticos
10.
Phys Biol ; 9(6): 065006, 2012 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-23197162

RESUMO

It is increasingly appreciated that phenotypic stochasticity plays fundamental roles in biological systems at the cellular level and that a variety of mechanisms generates phenotypic interconversion over a broad range of time scales. The ensuing dynamic heterogeneity can be used to understand biological and clinical processes involving diverse phenotypes in different cell populations. The same principles can be applied, not only to populations composed of cells, but also to populations composed of molecules, tissues, and multicellular organisms. Stochastic units generating dynamic heterogeneity can be integrated across various length scales. We propose that a graphical tool we have developed, called a metronomogram, will allow us to identify factors that suitably influence the restoration of homeostatic heterogeneity so as to modulate the consequences of dynamic heterogeneity for desired outcomes.


Assuntos
Processos Estocásticos , Animais , Formigas/fisiologia , Comportamento Animal , Biofilmes , Cryptococcus neoformans/fisiologia , Regulação Neoplásica da Expressão Gênica , Humanos , Modelos Biológicos , Metástase Neoplásica/patologia , Neoplasias/genética , Neoplasias/patologia , Oncogenes , Fenótipo , Proteoma/metabolismo , Receptor ErbB-2/genética
11.
Nat Rev Cancer ; 11(5): 375-82, 2011 05.
Artigo em Inglês | MEDLINE | ID: mdl-21508974

RESUMO

Cancer cells rapidly evolve drug resistance through somatic evolution and, in order to continue growth in the metastatic phase, violate the organism-wide consensus of regulated growth and beneficial communal interactions. We suggest that there is a fundamental mechanistic connection between the rapid evolution of resistance to chemotherapy in cellular communities within malignant tissues and the rapid evolution of antibiotic resistance in bacterial communities. We propose that this evolution is the result of a programmed and collective stress response performed by interacting cells, and that, given this fundamental connection, studying bacterial communities can provide deeper insights into the dynamics of adaptation and the evolution of cells within tumours.


Assuntos
Antineoplásicos/uso terapêutico , Farmacorresistência Bacteriana/fisiologia , Neoplasias/tratamento farmacológico , Neoplasias/patologia , Humanos , Modelos Biológicos , Neoplasias/etiologia
12.
J Vasc Surg ; 43(5): 1064-7, 2006 May.
Artigo em Inglês | MEDLINE | ID: mdl-16678708

RESUMO

We report a new procedure for embolization of hypogastric arteries simultaneously with aortoiliac stenting. Eight patients with aortoiliac (n = 6) and iliac (n = 2) aneurysms have been treated with this procedure. The technique involves the placement of a hook catheter near the hypogastric artery or in the sac, and the endoprosthesis insertion is done by using the same arteriotomy. The endoprosthesis is deployed and the coil is released. Saline is injected into the sac. The catheter is removed and the balloon at the distal end of the endoprosthesis is inflated. Computed tomography images showed periprosthesis or aneurysm thrombosis. No endoleaks or coils displacement in the sac were found.


Assuntos
Angioplastia/instrumentação , Aneurisma da Aorta Abdominal/cirurgia , Implante de Prótese Vascular/instrumentação , Embolização Terapêutica/instrumentação , Aneurisma Ilíaco/cirurgia , Pelve/irrigação sanguínea , Stents , Aneurisma da Aorta Abdominal/diagnóstico por imagem , Circulação Colateral/fisiologia , Terapia Combinada , Comorbidade , Seguimentos , Humanos , Aneurisma Ilíaco/diagnóstico por imagem , Desenho de Prótese , Tomografia Computadorizada por Raios X
13.
J Nutr ; 135(6): 1393-9, 2005 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-15930443

RESUMO

A number of nutrients are known to be effective in preventing cardiovascular disease (CVD). We investigated the possible effects of a daily intake of low amounts of these nutrients on risk factors and clinical parameters in patients with peripheral vascular disease and intermittent claudication (PVD-IC). Male PVD-IC patients (n = 60) were randomly allocated into 2 groups. The supplement (S) group consumed 500 mL/d of a fortified dairy product containing eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), oleic acid, folic acid, and vitamins A, B-6, D, and E. The control (C) group consumed 500 mL/d of semiskimmed milk with added vitamins A and D. The patients received lifestyle and dietary recommendations, and they were instructed to consume the products in addition to their regular diet. Blood extractions and clinical explorations were performed after 0, 3, 6, 9, and 12 mo. Plasma concentrations of EPA, DHA, oleic acid, folic acid, and vitamins B-6 and E increased after treatment with supplements (P < 0.05). Plasma total cholesterol and ApoB concentrations decreased in the S group, and total homocysteine decreased in those patients with high initial concentrations. Walking distance before the onset of claudication increased in the S group (P < 0.001), and ankle-brachial pressure index values increased (P < 0.05). The inclusion in the everyday diet of certain nutrients known to promote cardiovascular health improved clinical outcomes while reducing a variety of risk factors in men with PVD-IC, providing new evidence of the potential role of nutrition in the reduction of PVD-IC symptoms.


Assuntos
Claudicação Intermitente/tratamento farmacológico , Terapia Nutricional , Doenças Vasculares Periféricas/tratamento farmacológico , Doenças Vasculares Periféricas/fisiopatologia , Caminhada , Idoso , Método Duplo-Cego , Esquema de Medicação , Ácido Fólico/administração & dosagem , Ácido Fólico/uso terapêutico , Humanos , Claudicação Intermitente/fisiopatologia , Estudos Longitudinais , Masculino , Pessoa de Meia-Idade , Ácido Oleico/administração & dosagem , Ácido Oleico/uso terapêutico , Dor/fisiopatologia , Fatores de Risco , Vitamina B 6/administração & dosagem , Vitamina B 6/uso terapêutico , Vitamina E/administração & dosagem , Vitamina E/uso terapêutico
14.
J Biol Chem ; 280(16): 15992-6001, 2005 Apr 22.
Artigo em Inglês | MEDLINE | ID: mdl-15647271

RESUMO

Smad proteins are critical intracellular mediators of the transforming growth factor-beta, bone morphogenic proteins (BMPs), and activin signaling. Upon ligand binding, the receptor-associated R-Smads are phosphorylated by the active type I receptor serine/threonine kinases. The phosphorylated R-Smads then form heteromeric complexes with Smad4, translocate into the nucleus, and interact with various transcription factors to regulate the expression of downstream genes. Interaction of Smad proteins with cellular partners in the cytoplasm and nucleus is a critical mechanism by which the activities and expression of the Smad proteins are modulated. Here we report a novel step of regulation of the R-Smad function at the inner nuclear membrane through a physical interaction between the integral inner nuclear membrane protein MAN1 and R-Smads. MAN1, through the RNA recognition motif, associates with R-Smads but not Smad4 at the inner nuclear membrane in a ligand-independent manner. Overexpression of MAN1 results in inhibition of R-Smad phosphorylation, heterodimerization with Smad4 and nuclear translocation, and repression of transcriptional activation of the TGFbeta, BMP2, and activin-responsive promoters. This repression of TGFbeta, BMP2, and activin signaling is dependent on the MAN1-Smad interaction because a point mutation that disrupts this interaction abolishes the transcriptional repression by MAN1. Thus, MAN1 represents a new class of R-Smad regulators and defines a previously unrecognized regulatory step at the nuclear periphery.


Assuntos
Proteínas de Ligação a DNA/metabolismo , Proteínas de Membrana/metabolismo , Proteínas Nucleares/metabolismo , Transativadores/metabolismo , Fator de Crescimento Transformador beta/metabolismo , Proteína Morfogenética Óssea 2 , Proteínas Morfogenéticas Ósseas/metabolismo , Humanos , Proteínas de Membrana/genética , Membrana Nuclear/metabolismo , Proteínas Nucleares/genética , Fosforilação , Regiões Promotoras Genéticas , Transdução de Sinais , Proteínas Smad
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