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1.
Methods Enzymol ; 587: 71-86, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28253977

RESUMO

Macroautophagy is a specific variant of autophagy that involves a dedicated double-membraned organelle commonly known as autophagosome. Various methods have been developed to quantify the size of the autophagosomal compartment, which is an indirect indicator of macroautophagic responses, based on the peculiar ability of microtubule-associated protein 1 light chain 3 beta (MAP1LC3B; best known as LC3) to accumulate in forming autophagosomes upon maturation. One particularly convenient method to monitor the accumulation of mature LC3 within autophagosomes relies on a green fluorescent protein (GFP)-tagged variant of this protein and fluorescence microscopy. In physiological conditions, cells transfected temporarily or stably with a GFP-LC3-encoding construct exhibit a diffuse green fluorescence over the cytoplasm and nucleus. Conversely, in response to macroautophagy-promoting stimuli, the GFP-LC3 signal becomes punctate and often (but not always) predominantly cytoplasmic. The accumulation of GFP-LC3 in cytoplasmic dots, however, also ensues the blockage of any of the steps that ensure the degradation of mature autophagosomes, calling for the implementation of strategies that accurately discriminate between an increase in autophagic flux and an arrest in autophagic degradation. Various cell lines have been engineered to stably express GFP-LC3, which-combined with the appropriate controls of flux, high-throughput imaging stations, and automated image analysis-offer a relatively straightforward tool to screen large chemical or biological libraries for inducers or inhibitors of autophagy. Here, we describe a simple and robust method for the high-throughput quantification of GFP-LC3+ dots by automated fluorescence microscopy.


Assuntos
Autofagossomos/metabolismo , Ensaios de Triagem em Larga Escala/métodos , Microscopia de Fluorescência/métodos , Proteínas Associadas aos Microtúbulos/análise , Automação , Linhagem Celular Tumoral , Citoplasma/metabolismo , Proteínas de Fluorescência Verde/análise , Proteínas de Fluorescência Verde/genética , Humanos , Processamento de Imagem Assistida por Computador , Proteínas Associadas aos Microtúbulos/genética , Proteínas Associadas aos Microtúbulos/metabolismo , Neoplasias/metabolismo , Proteínas Recombinantes/análise , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo
2.
Methods Enzymol ; 588: 155-170, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28237099

RESUMO

Autophagy is an evolutionarily conserved process that mediates prominent homeostatic functions, both at the cellular and organismal level. Indeed, baseline autophagy not only ensures the disposal of cytoplasmic entities that may become cytotoxic upon accumulation, but also contributes to the maintenance of metabolic fitness in physiological conditions. Likewise, autophagy plays a fundamental role in the cellular and organismal adaptation to homeostatic perturbations of metabolic, physical, or chemical nature. Thus, the molecular machinery for autophagy is functionally regulated by a broad panel of sensors that detect indicators of metabolic homeostasis. Moreover, increases in autophagic flux have a direct impact on core metabolic circuitries including (but not limited to) glycolysis and mitochondrial respiration. Here, we detail a simple methodological approach to monitor these two processes in cultured cancer cells that mount a proficient autophagic response to stress.


Assuntos
Autofagia , Glicólise , Mitocôndrias/metabolismo , Técnicas de Cultura de Células/métodos , Células HCT116 , Humanos , Neoplasias/metabolismo , Consumo de Oxigênio
3.
Cell Death Differ ; 22(3): 499-508, 2015 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-25571976

RESUMO

Autophagy is a cellular recycling program that retards ageing by efficiently eliminating damaged and potentially harmful organelles and intracellular protein aggregates. Here, we show that the abundance of phosphatidylethanolamine (PE) positively regulates autophagy. Reduction of intracellular PE levels by knocking out either of the two yeast phosphatidylserine decarboxylases (PSD) accelerated chronological ageing-associated production of reactive oxygen species and death. Conversely, the artificial increase of intracellular PE levels, by provision of its precursor ethanolamine or by overexpression of the PE-generating enzyme Psd1, significantly increased autophagic flux, both in yeast and in mammalian cell culture. Importantly administration of ethanolamine was sufficient to extend the lifespan of yeast (Saccharomyces cerevisiae), mammalian cells (U2OS, H4) and flies (Drosophila melanogaster). We thus postulate that the availability of PE may constitute a bottleneck for functional autophagy and that organismal life or healthspan could be positively influenced by the consumption of ethanolamine-rich food.


Assuntos
Autofagia/fisiologia , Longevidade/fisiologia , Fosfatidiletanolaminas/fisiologia , Animais , Linhagem Celular Tumoral , Drosophila melanogaster , Humanos , Leveduras
4.
Cell Death Differ ; 22(3): 509-16, 2015 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-25526088

RESUMO

Several natural compounds found in health-related food items can inhibit acetyltransferases as they induce autophagy. Here we show that this applies to anacardic acid, curcumin, garcinol and spermidine, all of which reduce the acetylation level of cultured human cells as they induce signs of increased autophagic flux (such as the formation of green fluorescent protein-microtubule-associated protein 1A/1B-light chain 3 (GFP-LC3) puncta and the depletion of sequestosome-1, p62/SQSTM1) coupled to the inhibition of the mammalian target of rapamycin complex 1 (mTORC1). We performed a screen to identify the acetyltransferases whose depletion would activate autophagy and simultaneously inhibit mTORC1. The knockdown of only two acetyltransferases (among 43 candidates) had such effects: EP300 (E1A-binding protein p300), which is a lysine acetyltranferase, and NAA20 (N(α)-acetyltransferase 20, also known as NAT5), which catalyzes the N-terminal acetylation of methionine residues. Subsequent studies validated the capacity of a pharmacological EP300 inhibitor, C646, to induce autophagy in both normal and enucleated cells (cytoplasts), underscoring the capacity of EP300 to repress autophagy by cytoplasmic (non-nuclear) effects. Notably, anacardic acid, curcumin, garcinol and spermidine all inhibited the acetyltransferase activity of recombinant EP300 protein in vitro. Altogether, these results support the idea that EP300 acts as an endogenous repressor of autophagy and that potent autophagy inducers including spermidine de facto act as EP300 inhibitors.


Assuntos
Proteína p300 Associada a E1A/antagonistas & inibidores , Espermidina/farmacologia , Autofagia/efeitos dos fármacos , Autofagia/fisiologia , Linhagem Celular Tumoral , Proteína p300 Associada a E1A/metabolismo , Humanos
5.
Cell Prolif ; 46(2): 183-92, 2013 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-23510473

RESUMO

OBJECTIVES: Restorative properties of medicinal plants such as Genista sessilifolia DC. have often been suggested to occur, in epidemiological studies. However, full characterization of effective principles responsible for this action has never previously been performed. Here, we have characterized G. sessilifolia's anti-cancer effects and identified the chemical components involved in this anti-tumour action. MATERIALS AND METHODS: Cell cycle, apoptosis, necrosis, differentiation analyses, high-performance liquid chromatography, western blotting, RNA extraction, real-time PCR and primers have all been observed/used in the study. RESULTS: We report that G. sessilifolia methanol extract has anti-cancer activity on solid and haematological cancer cells. G. sessilifolia extract's anti-proliferative action is closely bound to induction of apoptosis, whereas differentiation is only weakly modulated. Analysis of G. sessilifolia extract, by high-performance liquid chromatography, identifies fraction 18-22 as the pertinent component for induction of apoptosis, whereas fractions 11-13 and 27-30 both seem to contribute to differentiation. G. sessilifolia extract induces apoptosis mediated by caspase activation and p21, Rb, p53, Bcl2-associated agonist of cell death (BAD), tumour necrosis factor receptor super-family, member 10 (TRAIL) overexpression and death receptor 5 (DR5). Accordingly, fraction 18-22 inducing apoptosis was able to induce TRAIL. CONCLUSIONS: Our results indicate that G. sessilifolia extract and its fraction 18-22 containing genistin and isoprunetin, were able to induce anti-cancer effects supporting the hypothesis of a pro-apoptotic intrinsic content of this natural medicinal plant.


Assuntos
Antineoplásicos Fitogênicos/farmacologia , Apoptose , Genista/química , Extratos Vegetais/farmacologia , Antineoplásicos Fitogênicos/química , Caspase 8/química , Caspase 8/genética , Ciclo Celular , Diferenciação Celular , Proliferação de Células/efeitos dos fármacos , Fracionamento Químico/métodos , Cromatografia Líquida de Alta Pressão , Ativação Enzimática , Citometria de Fluxo , Genisteína/química , Genisteína/isolamento & purificação , Genisteína/farmacologia , Granulócitos/efeitos dos fármacos , Granulócitos/patologia , Células HeLa , Humanos , Isoflavonas/química , Isoflavonas/isolamento & purificação , Isoflavonas/farmacologia , Células MCF-7 , Metanol/química , Componentes Aéreos da Planta/química , Extratos Vegetais/química , Reação em Cadeia da Polimerase em Tempo Real , Receptores do Ligante Indutor de Apoptose Relacionado a TNF/química , Receptores do Ligante Indutor de Apoptose Relacionado a TNF/genética , Ligante Indutor de Apoptose Relacionado a TNF/genética , Ligante Indutor de Apoptose Relacionado a TNF/metabolismo , Células U937 , Proteína de Morte Celular Associada a bcl/genética , Proteína de Morte Celular Associada a bcl/metabolismo
6.
Transplant Proc ; 45(1): 402-6, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23375329

RESUMO

Critical limb ischemia (CLI), a vascular disease affecting lower limbs, with high morbidity and mortality, is becoming a challenge due to the aging of the population. Patients without direct revascularization options have the worst outcomes. To date, 25% to 40% of CLI patients are not candidates for surgical or endovascular approaches, facing a major amputation as the ultimate option. This study sought to assess the safety and efficacy of transplantation of autologous bone marrow concentrates in "no-option" patients to restore blood perfusion by collateral flow and limb salvage. We performed a nonrandomized, noncontrolled pilot study for no-option CLI patients using intra-arterial infusion of autologous bone marrow concentrate. Variation of blood perfusion parameters, evaluated by laser doppler flowmetry after 6 and 12 months, was set as primary endpoint. Thirteen enrolled patients showed improvements in objective measurements of perfusion. This uncontrolled study provided evidence that transplantation of autologous bone marrow concentrates was well tolerated by CLI patients without significant adverse effects, demonstrating improved perfusion, confirming the feasibility and safety of the procedure.


Assuntos
Transplante de Medula Óssea/métodos , Extremidades/patologia , Isquemia/patologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Velocidade do Fluxo Sanguíneo , Medula Óssea/patologia , Feminino , Citometria de Fluxo , Seguimentos , Humanos , Leucócitos Mononucleares/citologia , Masculino , Pessoa de Meia-Idade , Doença Arterial Periférica/patologia , Projetos Piloto , Transplante Autólogo/métodos
7.
J Biol Regul Homeost Agents ; 26(1): 67-79, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-22475098

RESUMO

Peripheral arterial disease (PAD) is a chronic condition caused by atherosclerosis and is a severe complication of type 2 diabetes (T2D). We hypothesised that chronic condition of arterial disease engenders inflammation and endothelial damage in response to circulating cytokines released in the blood stream of PAD patients. We explored the levels of circulating cytokines in PAD patients with and without diabetes by multiplex cytokine array compared with non-PAD controls. Serum from PAD patients with or without diabetes showed high levels of VEGF, IFN-gamma, TNF-alpha, MCP-1, and EGF. VEGF levels correlated with TNF-alpha and IFN-gamma, significantly. Endothelial cells (ECs) were exposed to the different altered cytokines to evaluate changes in cell growth, migration and tubule-like formation, displaying impairment on proliferation, migration and tubule formation. Our findings demonstrate that a set of cytokines is significantly increased in the serum of PAD patients. These cytokines act to induce endothelial dysfunction synergistically. VEGF strongly correlated with TNF-alpha and IFN-gamma, opening new therapeutic perspectives.


Assuntos
Citocinas/sangue , Endotélio Vascular/fisiopatologia , Doença Arterial Periférica/sangue , Doença Arterial Periférica/fisiopatologia , Idoso , Idoso de 80 Anos ou mais , Estudos de Casos e Controles , Hipóxia Celular , Movimento Celular , Proliferação de Células , Quimiocina CCL2/sangue , Citocinas/farmacologia , Diabetes Mellitus Tipo 2/sangue , Diabetes Mellitus Tipo 2/complicações , Diabetes Mellitus Tipo 2/fisiopatologia , Endotélio Vascular/citologia , Fator de Crescimento Epidérmico/sangue , Feminino , Células Endoteliais da Veia Umbilical Humana/efeitos dos fármacos , Humanos , Interferon gama/sangue , Masculino , Pessoa de Meia-Idade , Doença Arterial Periférica/etiologia , Fator de Necrose Tumoral alfa/sangue , Fator A de Crescimento do Endotélio Vascular/sangue
8.
Cell Prolif ; 45(1): 22-31, 2012 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-22172154

RESUMO

OBJECTIVES: Curative properties of medicinal plants such as Psidium guajava L. (Myrtaceae) have often been indicated by epidemiological studies on populations in which these fruits are consumed daily. However, complete characterization of the active principles responsible for this ability has never been performed. Here, we have characterized P. guajava's anti-cancer potential and identified the parts of the fruit involved in its anti-neoplastic action. MATERIALS AND METHODS: We studied morphology of our cells, cell cycle characteristics and apoptosis and performed immunostaining, differentiation and western blot analyses. RESULTS: We report that the P. guajava extract exerted anti-cancer control on both haematological and solid neoplasias. P. guajava extract's anti-tumour properties were found to be tightly bound to induction of apoptosis and differentiation. Use of ex vivo myeloid leukaemia blasts corroborated that P. guajava was able to induce cell death but did not exhibit anti-cancer effects on all malignant cells investigated, indicating selective activity against certain types of tumour. Analyses of P. guajava pulp, peel and seeds identified the pulp as being the most relevant component for causing cell cycle arrest and apoptosis, whereas peel was responsible for causing cell differentiation. P. guajava itself and its pulp-derived extract were found to induce apoptosis accompanied by caspase activation and p16, p21, Fas ligand (FASL TNF super-family, member 6), Bcl-2-associated agonist of cell death (BAD) and tumour necrosis factor receptor super-family, member 10b (DR5), overexpression. CONCLUSIONS: Our findings showed that P. guajava L. extract was able to exert anti-cancer activity on cultures in vitro and ex vivo, supporting the hypothesis of its anti malignant pro-apoptotic modulation.


Assuntos
Antineoplásicos Fitogênicos/farmacologia , Apoptose/efeitos dos fármacos , Diferenciação Celular/efeitos dos fármacos , Fitoterapia , Psidium , Caspases/metabolismo , Ciclo Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Humanos , Leucemia Promielocítica Aguda/tratamento farmacológico , Leucemia Promielocítica Aguda/metabolismo , Leucemia Promielocítica Aguda/patologia , Proteínas de Neoplasias/metabolismo , Extratos Vegetais/farmacologia , Plantas Medicinais , Células U937
9.
Stem Cells Cloning ; 5: 5-14, 2012 Sep 06.
Artigo em Inglês | MEDLINE | ID: mdl-24198534

RESUMO

Inadequate blood supply to tissues caused by obstruction of arterioles and/or capillaries results in ischemic injuries - these injuries can range from mild (eg, leg ischemia) to severe conditions (eg, myocardial infarction, stroke). Surgical and/or endovascular procedures provide cutting-edge treatment for patients with vascular disorders; however, a high percentage of patients are currently not treatable, owing to high operative risk or unfavorable vascular involvement. Therapeutic angiogenesis has recently emerged as a promising new therapy, promoting the formation of new blood vessels by the introduction of bone marrow-derived stem and progenitor cells. These cells participate in the development of new blood vessels, the enlargement of existing blood vessels, and sprouting new capillaries from existing blood vessels, providing evidence of the therapeutic utility of these cells in ischemic tissues. In this review, the authors describe peripheral arterial disease, an ischemic condition affecting the lower extremities, summarizing different aspects of vascular regeneration and discussing which and how stem cells restore the blood flow. The authors also present an overview of encouraging results from early-phase clinical trials using stem cells to treat peripheral arterial disease. The authors believe that additional research initiatives should be undertaken to better identify the nature of stem cells and that an intensive cooperation between laboratory and clinical investigators is needed to optimize the design of cell therapy trials and to maximize their scientific rigor. Only this will allow the results of these investigations to develop best clinical practices. Additionally, although a number of stem cell therapies exist, many treatments are performed outside international and national regulations and many clinical trials have been not registered on databases such as ClinicalTrials.gov or EudraCT. Therefore, more rigorous clinical trials are required to confirm the first hopeful results and to address the challenging issues.

10.
Environ Toxicol Pharmacol ; 33(1): 9-15, 2012 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-22047638

RESUMO

Pregnant adult Balb-C mice were exposed daily to two different doses of Bisphenol A (BPA) by subcutaneous injection beginning on gestational day 1 through the seventh day after delivery. The mothers were sacrificed on postpartum day 21, and the offspring were sacrificed at 3 months of age. Control mice were subjected to the same experimental protocol but received saline injections. The liver, muscles, hindbrain and forebrain of the offspring were dissected and processed using HPLC to assess the level of BPA in the tissues and to determine its dependence on the exposure dose and gender. For comparison, the same tissues were dissected from the mothers and analysed. We report the following results: (1) the level of BPA that accumulated in a given tissue was dependent on the exposure dose; (2) the rank order of BPA accumulation in the various tissues was dependent on the gender of the offspring; (3) the average BPA concentrations in the liver and muscle of the female offspring were higher than in the males; and (4) the average BPA concentration in the central nervous system (i.e., the hindbrain and forebrain) of the male offspring was higher than in the females.


Assuntos
Estrogênios não Esteroides/metabolismo , Fenóis/metabolismo , Animais , Compostos Benzidrílicos , Estrogênios não Esteroides/administração & dosagem , Feminino , Humanos , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Fenóis/administração & dosagem , Gravidez , Distribuição Tecidual
11.
Environ Toxicol Pharmacol ; 31(1): 198-204, 2011 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-21787686

RESUMO

Octylphenol (OP) is an endocrine-disrupting chemical that accumulates in various organs. It has also been shown to exert noxious effects on the central nervous system. In the present study, we measured in Sprague-Dawley rats the degree of OP accumulation in different areas of the brain and investigated the effect of OP in pain modulation. Two groups of male Sprague-Dawley rats were treated for 20 days with 50mg/kg BW/day of OP (group 1) or vehicle (group 2). At the end of the treatment, the formalin test was performed to evaluate the effect of OP exposure on pain. Soon after, rats were sacrificed, and the accumulation of OP in the cerebral cortex, hippocampus, hypothalamus, cerebellum, thalamus, striatum, mesencephalus and ventral hindbrain was measured by HPLC analysis. The results showed a greater accumulation of OP in the cerebral cortex compared to all the other areas; there was also more accumulation in the cerebellum compared to the mesencephalus and thalamus. No accumulation was found in the striatum. These results suggest that there is a preferential accumulation of OP in different areas of the brain with consequences to neural behaviour. On the contrary, experiments on facial grooming did not show significant effects of OP on pain.


Assuntos
Encéfalo/metabolismo , Disruptores Endócrinos/farmacocinética , Poluentes Ambientais/farmacocinética , Poluição Ambiental/efeitos adversos , Fenóis/farmacocinética , Animais , Cromatografia Líquida de Alta Pressão , Asseio Animal/efeitos dos fármacos , Crescimento/efeitos dos fármacos , Masculino , Ratos , Ratos Sprague-Dawley
12.
Chemosphere ; 82(3): 405-10, 2011 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-20971495

RESUMO

Bisphenol A (BPA) is an endocrine disruptor (ED) that is abundant in the environment because of its extensive use in human-manufactured products. In this study, the BPA concentration was measured in the muscle and liver of five edible fish, characterized by different habitat and habits, caught in two different sites of the Tyrrhenian Sea (Italy). Our results show that: (i) fish livers are about 2.5 times more polluted than muscle; (ii) fish caught in the Gulf of Naples are more polluted than those from the Latium coasts, ranging from 1.2-fold more for White Bream to 6.6-fold for Grey Mullet; and (iii) the percentages of fish found to be BPA-polluted in the Gulf of Naples ranged from 73% (for Bass) to 90% (for Mullet), while the Latium fish range from 60% (for Bass) to 90% (for Mullet). These data indicate that consumers of fish caught in the Gulf of Naples are at a greater risk for BPA-induced endocrine pathologies compared to those who consume fish caught along the Latium coasts.


Assuntos
Disruptores Endócrinos/metabolismo , Peixes/metabolismo , Fenóis/metabolismo , Poluentes Químicos da Água/metabolismo , Animais , Compostos Benzidrílicos , Monitoramento Ambiental , Itália , Fígado/metabolismo , Músculos/metabolismo , Oceanos e Mares , Água do Mar/química
13.
Transplant Proc ; 42(7): 2816-20, 2010 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-20832596

RESUMO

Restoring blood flow to ischemic tissue is a prerequisite for treatment of ischemic diseases. Cell-based therapy based on bone marrow transplantation is a promising option for patients with critical limb ischemia (CLI). The efficacy of cell therapies to augment neovascularization seems to involve endothelial progenitor cells (EPCs); however, the mechanisms underlying the efficacy have not been fully elucidated. Herein we have described the case of a young patient with severe CLI, who experienced a 24-month beneficial clinical response to autologous bone marrow transplantation. The exceptional amelioration enabled him to perform standardized maximal treadmill exercise test that demonstrated lack of exercise-induced EPC mobilization, despite adequate stromal-derived factor 1 and vascular endothelial growth factor responses. Therefore, tissue ischemia is not sufficient to promote the recruitment of EPCs that have been demonstrated to be involved in the recovery from ischemia. The local implantation of marrow-derived elements may provide cells and/or trophic factors, which have the capacity to augment angiogenesis, opening new approaches to the etiopathogenesis of the disease.


Assuntos
Arteriopatias Oclusivas/complicações , Transplante de Medula Óssea/métodos , Mobilização de Células-Tronco Hematopoéticas/métodos , Isquemia/patologia , Perna (Membro)/irrigação sanguínea , Adulto , Aorta Abdominal/diagnóstico por imagem , Velocidade do Fluxo Sanguíneo , HDL-Colesterol/sangue , Humanos , Hiperemia/diagnóstico por imagem , Hiperemia/fisiopatologia , Artéria Ilíaca/diagnóstico por imagem , Isquemia/etiologia , Testes de Função Renal , Testes de Função Hepática , Masculino , Neovascularização Fisiológica , Tomografia Computadorizada por Raios X
14.
Bone Marrow Transplant ; 42(10): 667-72, 2008 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-18695661

RESUMO

Long-term effects of autologous mononuclear bone marrow cell transplantation were studied in patients with severe peripheral arterial disease (PAD) and critical limb ischemia. Ten patients with end-stage disease were infused twice with autologous bone marrow cells and they completed the 12-month follow-up study. Substantial improvement of blood flow and increasing capillary densities were seen when compared with a concomitant control group comprising patients who did not enroll in the study. The ankle-brachial index (ABI) and pain-free walking distance improved significantly in treated patients. The improvement was sustained 12 months after treatment. These results confirm that the autologous bone marrow transplantation is an effective therapeutic strategy in critical limb ischemia.


Assuntos
Transplante de Medula Óssea , Doenças Vasculares Periféricas/terapia , Adulto , Idoso , Idoso de 80 Anos ou mais , Índice Tornozelo-Braço , Velocidade do Fluxo Sanguíneo , Feminino , Humanos , Isquemia/terapia , Perna (Membro)/patologia , Estudos Longitudinais , Masculino , Pessoa de Meia-Idade , Reoperação , Transplante Autólogo , Resultado do Tratamento , Caminhada
15.
Oncogene ; 26(3): 382-94, 2007 Jan 18.
Artigo em Inglês | MEDLINE | ID: mdl-16878156

RESUMO

We show that human osteosarcoma cells (Saos-2) have downregulation of alpha3beta1-integrin compared to normal bone cells; this was further described in human osteosarcomas and in a primary murine sarcoma. The alpha3 gene was silenced in Saos-2 cells causing a low expression of alpha3beta1-integrin and reduction in collagen attachment with increasing migratory capacity. Chromatin immunoprecipitation assay performed on alpha3 promoter established that Myc and Yin Yang protein (YY1) cooperate in tandem to downregulate the alpha3 gene. This silencing mechanism involves the binding of Myc and YY1 to DNA and formation of complexes among Myc/Max, YY1, CREB-binding protein and deacetylation activity. The promoter containing deletions of E-boxes or YY1 cassettes failed to downregulate the transcription of a reporter gene as well as the inhibition of deacetylation activity. Overexpression of both Myc and YY1 was necessary to determine the alpha3-integrin promoter downregulation in normal osteoblasts. This downregulation of alpha3beta1-integrin can contribute to the acquisition of a more aggressive phenotype. YY1 regulated negatively the Myc activity through a direct interaction with the Myc/Max and deacetylase complexes. This represents a novel silencing mechanism with broad implications in the transcription machinery of tumours.


Assuntos
Inativação Gênica , Integrina alfa3/genética , Integrina alfa3beta1/metabolismo , Osteossarcoma/metabolismo , Proteínas Proto-Oncogênicas c-myc/metabolismo , Fator de Transcrição YY1/metabolismo , Animais , Sequência de Bases , Fatores de Transcrição de Zíper de Leucina Básica/metabolismo , Western Blotting , Neoplasias Ósseas/metabolismo , Neoplasias Ósseas/patologia , Imunoprecipitação da Cromatina , Colágeno/metabolismo , Regulação para Baixo , Ensaio de Desvio de Mobilidade Eletroforética , Feminino , Imunofluorescência , Humanos , Laminina/metabolismo , Camundongos , Camundongos Nus , Dados de Sequência Molecular , Osteoblastos/citologia , Osteoblastos/metabolismo , Osteossarcoma/genética , Osteossarcoma/patologia , Regiões Promotoras Genéticas/genética , RNA Interferente Pequeno/farmacologia , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Transcrição Gênica , Transfecção , Células Tumorais Cultivadas , Fator de Transcrição YY1/antagonistas & inibidores , Fator de Transcrição YY1/genética
16.
Scand J Clin Lab Invest ; 66(5): 407-27, 2006.
Artigo em Inglês | MEDLINE | ID: mdl-16901851

RESUMO

Experimental models have enhanced our understanding of atherothrombosis pathophysiology and have played a major role in the search for adequate therapeutic interventions. Various animal models have been developed to simulate thrombosis and to study in vivo parameters related to hemodynamics and rheology that lead to thrombogenesis. Although no model completely mimics the human condition, much can be learned from existing models about specific biologic processes in disease causation and therapeutic intervention. In general, large animals such as pigs and monkeys have been better suited to study atherosclerosis and arterial and venous thrombosis than smaller species such as rats, rabbits, and dogs. On the other hand, mouse models of arterial and venous thrombosis have attracted increasing interest over the past two decades, owing to direct availability of a growing number of genetically modified mice, improved technical feasibility, standardization of new models of local thrombosis, and low maintenance costs. To simulate rupture of an atherosclerotic plaque, models of arterial thrombosis often involve vascular injury, which can be achieved by several means. There is no animal model that is sufficiently tall, that can mimic the ability of humans to walk upright, and that possesses the calf muscle pump that plays an important role in human venous hemodynamics. A number of spontaneous or genetically engineered animals with overexpression or deletion of various elements in the coagulation, platelet, and fibrinolysis pathways are now available. These animal models can replicate important aspects of thrombosis in humans, and provide a valuable resource in the development of novel concepts of disease mechanisms in human patients.


Assuntos
Modelos Animais , Trombose/metabolismo , Trombose/patologia , Animais , Artérias/lesões , Artérias/metabolismo , Humanos , Hiper-Homocisteinemia/metabolismo , Trombose/genética , Veias/lesões , Veias/metabolismo
17.
Curr Med Chem ; 12(15): 1755-72, 2005.
Artigo em Inglês | MEDLINE | ID: mdl-16029145

RESUMO

New approaches to atherosclerosis-related diseases include novel uses of proven treatments and development of innovative agents. Several commonly used cardiovascular drugs such as dihydropyridine calcium antagonists, ACE inhibitors containing the sulphydryl group, or highly lipophilic beta-blockers have some anti-atherosclerotic activities. Moreover, new clinical trials suggesting that additional reduction of low-density lipoprotein cholesterol levels with statin therapy results in additional benefit in coronary heart disease prevention. Notably, new cholesterol transport or bile acid transport inhibitors have been found to produce significant reductions in intestinal cholesterol absorption and experimental atherosclerosis. Inhibitors of acyl coenzyme A:cholesterol acyltransferase, which can reduce cholesterol storage in macrophages and in arterial lesions, have also been developed. Finally, newer therapeutical strategies against atherogenesis may include the use of antioxidants and cholestyramine during pregnancy or the development of metalloproteinase inhibitors.


Assuntos
Arteriosclerose/tratamento farmacológico , Fármacos Cardiovasculares/uso terapêutico , Fármacos Cardiovasculares/classificação , Feminino , Humanos , Gravidez , Complicações na Gravidez/tratamento farmacológico
19.
Exp Gerontol ; 40(1-2): 43-50, 2005.
Artigo em Inglês | MEDLINE | ID: mdl-15664731

RESUMO

Ischemic preconditioning (IP) has been proposed as an endogenous form of protection against ischemia reperfusion injury. IP, however, does not prevent post-ischemic dysfunction in the aging heart but may be partially corrected by exercise training and food restriction. We investigated the role of exercise training combined with food restriction on restoring IP in the aging heart. Effects of IP against ischemia-reperfusion injury in isolated hearts from adult (A, 6 months old), sedentary 'ad libitum' fed (SL), trained ad libitum fed (TL), sedentary food-restricted (SR), trained- and food-restricted senescent rats (TR) (24 months old) were investigated. Norepinephrine release in coronary effluent was determined by high performance liquid cromatography. IP significantly improved final recovery of percent developed pressure in hearts from A (p<0.01) but not in those from SL (p=NS) vs unconditioned controls. Developed pressure recovery was partial in hearts from TL and SR (64.3 and 67.3%, respectively; p<0.05 vs controls) but it was total in those from TR (82.3%, p=NS vs A; p<0.05 vs hearts from TL and SR). Similarly, IP determined a similar increase of norepinephrine release in A (p<0.001) and in TR (p<0.001, p=NS vs adult). IP was abolished by depletion of myocardial norepinephrine stores by reserpine in all groups. Thus, IP reduces post-ischemic dysfunction in A but not in SL. Moreover, IP was preserved partially in TR and SR and totally in TR. Complete IP maybe due to full restoration of norepinephrine release in response to IP stimulus.


Assuntos
Envelhecimento/fisiologia , Restrição Calórica , Precondicionamento Isquêmico Miocárdico , Traumatismo por Reperfusão Miocárdica/prevenção & controle , Condicionamento Físico Animal/fisiologia , Animais , Peso Corporal/fisiologia , Ventrículos do Coração/patologia , Masculino , Traumatismo por Reperfusão Miocárdica/metabolismo , Traumatismo por Reperfusão Miocárdica/fisiopatologia , Norepinefrina/metabolismo , Tamanho do Órgão/fisiologia , Ratos , Ratos Wistar
20.
Am Heart J ; 148(1): e5, 2004 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-15215814

RESUMO

BACKGROUND: Essential hypertension is associated with enhanced LDL oxidation and impaired endothelium-dependent vasodilation. The antioxidant status is linked to the nitric oxide (NO) pathway. Sulfhydryl angiotensin-converting enzyme (ACE) inhibitors inhibit oxidative stress and atherogenesis in experimental models; therefore we tested whether this beneficial antioxidant activity could be also clinically relevant in patients with essential hypertension. METHODS: Plasma LDL oxidizability was investigated initially in untreated normocholesterolemic patients with moderate essential hypertension without clinically evident target organ damage (n = 96) and in control normotensive subjects (n = 46). Patients were then randomly assigned into two age- and sex-matched groups to receive the new sulfhydryl ACE inhibitor zofenopril (15 to 30 mg/d; n = 48) or enalapril (20 mg/d, n = 48). LDL oxidizability was evaluated (generation of malondialdehyde, MDA) and systemic oxidative stress was evaluated by isoprostanes (8-isoPGF2alpha). Asymmetrical dimethyl-L-arginine (ADMA), a competitive inhibitor of endothelial NO synthase, and plasma nitrite and nitrates (NOx) were also measured. RESULTS: LDL from hypertensive subjects had enhanced susceptibility to oxidation in vitro compared with that in control subjects (P <.05). Similarly, isoprostanes were significantly increased (P <.01) in hypertensive subjects versus control subjects. After 12-week treatment, MDA levels were significantly reduced by zofenopril (P <.05) but not enalapril treatment (P = not significant). Isoprostanes were normalized after zofenopril treatment (P <.03), whereas enalapril was ineffective. After treatment with both ACE inhibitors, plasma NOx concentrations were significantly reduced (P <.05). Similarly, hypertension increased ADMA concentration compared with the normotensive state, whereas ACE inihibition elicited a significant decrease. However, the reduction of ADMA concentration was significantly higher in patients receiving sulfhydryl ACE inhibition (P <.05 vs enalapril). CONCLUSIONS: The sulfhydryl ACE inhibitor zofenopril reduces oxidative stress and improves the NO pathway in patients with essential hypertension. If confirmed in a large multicenter clinical trial, our data suggest a possible vasculoprotective effect of the compound in retarding vascular dysfunction and atherogenesis that often develops rapidly in hypertensive patients.


Assuntos
Inibidores da Enzima Conversora de Angiotensina/farmacologia , Arginina/análogos & derivados , Captopril/análogos & derivados , Captopril/farmacologia , Enalapril/farmacologia , Hipertensão/tratamento farmacológico , Óxido Nítrico/metabolismo , Estresse Oxidativo/efeitos dos fármacos , Inibidores da Enzima Conversora de Angiotensina/uso terapêutico , Arginina/metabolismo , Captopril/uso terapêutico , Enalapril/uso terapêutico , Feminino , Humanos , Hipertensão/metabolismo , Peroxidação de Lipídeos/efeitos dos fármacos , Lipoproteínas LDL/metabolismo , Masculino , Pessoa de Meia-Idade , Nitratos/sangue , Nitritos/sangue
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