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1.
Front Cell Dev Biol ; 8: 555937, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33072745

RESUMO

MicroRNAs (miRNAs) are dysregulated in the context of many cancer types, making them potentially ideal diagnostic or therapeutic targets in patients in which they are aberrantly expressed. In the present study, we found miR-7 to be downregulated in gastric cancer (GC), and we further determined its expression to be closely linked to GC sensitivity to the chemotherapeutic compound cisplatin. This effect appears to be at least partially attributable to the regulation of LDH-A, which is a miR-7 target gene and expression of LDH-A is negatively correlated with miR-7 expression in primary GC tumor samples. When upregulated, we also determined that miR-7 was able to inhibit the proliferation, colony formation, and glycolysis of GC cells owing to its regulation of LDH-A. Moreover, overexpression of miR-7 render cells more sensitive to cisplatin. Our results thus provide novel evidence that miR-7 is a key mediator of GC growth and chemosensitivity through its regulation of LDH-A, thus potentially highlighting this pathway as a therapeutic target for treating affected patients.

2.
Nucleic Acids Res ; 48(17): 9747-9761, 2020 09 25.
Artigo em Inglês | MEDLINE | ID: mdl-32853372

RESUMO

Kinetoplastid flagellates are known for several unusual features, one of which is their complex mitochondrial genome, known as kinetoplast (k) DNA, composed of mutually catenated maxi- and minicircles. Trypanosoma lewisi is a member of the Stercorarian group of trypanosomes which is, based on human infections and experimental data, now considered a zoonotic pathogen. By assembling a total of 58 minicircle classes, which fall into two distinct categories, we describe a novel type of kDNA organization in T. lewisi. RNA-seq approaches allowed us to map the details of uridine insertion and deletion editing events upon the kDNA transcriptome. Moreover, sequencing of small RNA molecules enabled the identification of 169 unique guide (g) RNA genes, with two differently organized minicircle categories both encoding essential gRNAs. The unprecedented organization of minicircles and gRNAs in T. lewisi broadens our knowledge of the structure and expression of the mitochondrial genomes of these human and animal pathogens. Finally, a scenario describing the evolution of minicircles is presented.


Assuntos
Mitocôndrias/genética , RNA Guia/genética , RNA de Protozoário/genética , Trypanosoma lewisi/genética , Adenosina Trifosfatases/genética , DNA de Protozoário/genética , Genoma Mitocondrial , Sequenciamento de Nucleotídeos em Larga Escala , Filogenia , Subunidades Proteicas/genética , Edição de RNA
3.
Front Oncol ; 10: 643, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32435616

RESUMO

Downregulation of microRNA-200b (miR-200b) has been identified in a range of cancers, yet the specific mechanisms whereby it influences lung cancer growth require further exploration. We determined that lung cancer patient tumor samples exhibit decreased miR-200b expression, and we further found this miRNA to inhibit tumor growth via interfering with ERK1/2 and AKT signaling, targeting p70S6K1 to suppress HIF-1α expression. This miRNA further rendered H1299 cells more sensitive to cisplatin while impairing their proliferative and invasive potential through its ability to target and inhibit the activity of p70S6K1. These results were further confirmed in a murine xenograft model in which miR-200b also inhibited the growth of tumor and suppressed p70S6K1, p-AKT, p-ERK1/2, and HIF-1α expression. These findings clearly demonstrate a role for miR-200b in suppressing lung cancer development, making it a potentially relevant target for future diagnostic and therapeutic interventions.

4.
Front Pharmacol ; 10: 1002, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31572184

RESUMO

Esophagus cancer is the seventh cause of cancer-related deaths globally. In this study, we analyzed interleukin 6 (IL-6) gene expression in human esophagus cancer patients and showed that IL-6 mRNA levels are significantly higher in tumor tissues and negatively correlated with overall survival, suggesting that IL-6 is a potential therapeutic target for esophagus cancer. We further demonstrated that apigenin, a nature flavone product of green plants, inhibited IL-6 transcription and gene expression in human esophagus cancer Eca-109 and Kyse-30 cells. Apigenin significantly and dose-dependently inhibited cell proliferation and promoted apoptosis while stimulating the cleaved PARP (poly ADP-ribose polymerase) (C-PARP) and caspase-8 expression. It suppressed VEGF (Vascular endothelial growth Factor) expression and tumor-induced angiogenesis. Pretreatment of cells with IL-6 could completely reverse apigenin-induced cellular changes. Finally, using a preclinical nude mice model subcutaneously xenografted with Eca-109 cells, we demonstrated the in vivo antitumor activity and mechanisms of apigenin. Taken together, this study revealed for the first time that apigenin is a new IL-6 transcription inhibitor and that inhibiting IL-6 transcription is one of the mechanisms by which apigenin exhibits its anticancer effects. The potential clinical applications of apigenin in treating esophagus cancer warrant further investigations.

5.
Mol Med Rep ; 18(1): 495-501, 2018 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-29749486

RESUMO

The present study aimed to investigate the effects of obatoclax (OBX) combined with gemcitabine (GEM) treatment on the proliferation, migration, invasion and epithelial­mesenchymal transition (EMT) related proteins of pancreatic cancer cell line BxPC­3 under hypoxic conditions. Protein expression levels of hypoxia­inducible factor 1α (HIF­1α) in BxPC­3 pancreatic cancer cells under normoxic and hypoxic conditions were detected by western blotting. Cells were divided into four groups: Normoxia group, hypoxia group, OBX group and OBX + GEM group. The proliferation activity of BxPC­3 cells was detected by Cell Counting kit­8. The migratory and invasive abilities of BxPC­3 cells were detected by the scratch test and Matrigel assay, respectively. The protein expression levels of vimentin, E­cadherin and p53 in BxPC­3 cells were also detected by western blotting. HIF­1α expression under hypoxic conditions was significantly increased compared with expression under normoxic conditions. Under hypoxic conditions, OBX treatment reduced cell activity, decreased cell migration and invasion, promoted the expression of E­cadherin and p53. In the OBX + GEM group, BxPC­3 cell activity decreased significantly, cell migration and invasion decreased significantly, the expression of vimentin was significantly reduced and the expression of E­cadherin and p53 further increased. In conclusion, the present results demonstrated that under hypoxic conditions, OBX combined with a small dose of GEM may be able to inhibit the growth, migration and invasion of pancreatic cancer cells, possibly via inhibition of EMT process. These results may provide a promising strategy for pancreatic cancer therapy.


Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/farmacologia , Movimento Celular/efeitos dos fármacos , Transição Epitelial-Mesenquimal/efeitos dos fármacos , Neoplasias Pancreáticas/tratamento farmacológico , Caderinas/metabolismo , Hipóxia Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Desoxicitidina/análogos & derivados , Desoxicitidina/farmacologia , Humanos , Invasividade Neoplásica , Neoplasias Pancreáticas/metabolismo , Neoplasias Pancreáticas/patologia , Pirróis/farmacologia , Proteína Supressora de Tumor p53/metabolismo
6.
World J Gastroenterol ; 23(10): 1796-1803, 2017 Mar 14.
Artigo em Inglês | MEDLINE | ID: mdl-28348485

RESUMO

AIM: To explore the anti-tumor effects of esophageal cancer-related gene 2 (ECRG2) in combination with cisplatin (DDP) in DDP-resistant esophageal cancer cells (EC9706/DDP). METHODS: A drug-resistant cell model was established, with EC9706/DDP cells being treated with ECRG2 and/or DDP. Cell viability was examined by MTT assay. The rate of cell apoptosis was determined by flow cytometry. The mRNA expression levels of proliferating cell nuclear antigen (PCNA), metallothionein (MT), and p53 were determined by RT-PCR and PCNA, while MT and p53 protein expression levels were determined by western blotting. RESULTS: The anti-proliferative effect of ECRG2 in combination with DDP was superior when compared to ECRG2 or DDP alone. The inhibition rate for the combination reached its peak (51.33%) at 96 h. The early apoptotic rates of the control, ECRG2 alone, DDP alone, and ECRG2 plus DDP groups were 5.71% ± 0.27%, 12.68% ± 0.61%, 14.15% ± 0.87%, and 27.96% ± 0.36%, respectively. Although all treatment groups were significantly different from the control group (P < 0.05), the combination treatment of ECRG2 plus DDP performed significantly better when compared to either ECRG2 or DDP alone (P < 0.05). The combination of ECRG2 and DDP significantly upregulated p53 mRNA and protein levels and downregulated PCNA mRNA and protein levels compared to ECRG2 or DDP alone (P < 0.05). However, no changes were seen in the expression of MT mRNA or protein. CONCLUSION: ECRG2 in combination with DDP can inhibit viability and induce apoptosis in esophageal cancer DDP-resistant cells, possibly via upregulation of p53 expression and downregulation of PCNA expression. These findings suggest that the combination of ECRG2 and DDP may be a promising strategy for the clinical treatment of esophageal cancers that are resistant to DDP.


Assuntos
Antineoplásicos/farmacologia , Cisplatino/farmacologia , Resistencia a Medicamentos Antineoplásicos/efeitos dos fármacos , Neoplasias Esofágicas/tratamento farmacológico , Antígeno Nuclear de Célula em Proliferação/metabolismo , Proteínas Secretadas Inibidoras de Proteinases/uso terapêutico , Proteína Supressora de Tumor p53/metabolismo , Antineoplásicos/uso terapêutico , Apoptose/efeitos dos fármacos , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Cisplatino/uso terapêutico , Regulação para Baixo , Quimioterapia Combinada , Neoplasias Esofágicas/fisiopatologia , Citometria de Fluxo , Humanos , Metalotioneína/metabolismo , Proteínas Secretadas Inibidoras de Proteinases/farmacologia , RNA Mensageiro/metabolismo , Proteínas Recombinantes/farmacologia , Proteínas Recombinantes/uso terapêutico , Inibidores de Serinopeptidase do Tipo Kazal , Ativação Transcricional , Regulação para Cima
7.
Cell Biol Toxicol ; 32(1): 37-59, 2016 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-27027780

RESUMO

Drug-induced liver injury (DILI) is a leading cause of discontinuation of new drug approval or withdrawal of marketed medicine based on safety due to organ vulnerability. The aim of this research is to investigate the potential abilities of four different in vitro cell models (L-02, HepG2, HepaRG, and hiHeps cell lines) in assessing marketed drugs labeled with apparently different types of liver injury. A total of 17 drugs with versatile pharmacological profiles were chosen, of which, 14 drugs are recognized as DILI agents and 3 drugs are DILI irrelevant. Preliminary cellular screening assays indicated that the HepaRG cell line had an advantage over other cell lines in predicting drugs associated with DILI in vitro as it had the highest Youden's index (71.4%). A multi-parametric screening assay showed that oxidative stress, mitochondrial damage, and disorders of neutral lipid metabolism were changed notably in the HepaRG cell line after DILI-related drugs exposure, accounting for its high sensitivity in comparison with other three cell lines. In addition, aspartate aminotransferase (AST), lactate dehydrogenase (LDH), and malate dehydrogenase (MDH) all correlated with the cytotoxic effects of diclofenac sodium (p < 0.05), buspirone hydrochloride (p < 0.01), and danazol (p < 0.01) in the HepaRG cell line. We conclude that the HepaRG cell line is a superior in vitro cell model to other three cell lines for evaluating drugs with DILI potential.


Assuntos
Doença Hepática Induzida por Substâncias e Drogas/etiologia , Aspartato Aminotransferases/metabolismo , Linhagem Celular Tumoral , Doença Hepática Induzida por Substâncias e Drogas/enzimologia , Doença Hepática Induzida por Substâncias e Drogas/metabolismo , Doença Hepática Induzida por Substâncias e Drogas/patologia , Células Hep G2/metabolismo , Hepatócitos/citologia , Hepatócitos/efeitos dos fármacos , Hepatócitos/enzimologia , Humanos , L-Lactato Desidrogenase/metabolismo , Metabolismo dos Lipídeos , Fígado/citologia , Fígado/efeitos dos fármacos , Fígado/enzimologia , Malato Desidrogenase/metabolismo
8.
Zhong Yao Cai ; 38(11): 2331-4, 2015 Nov.
Artigo em Chinês | MEDLINE | ID: mdl-27356387

RESUMO

OBJECTIVE: To study the effects of Germanium (Ge) concentration on Ge accumulation and biotransformation of polysaccarified Ge (PG) in Cordyceps militaris. METHODS: Solid and liquid culture were used in this study. RESULTS: In the solid culture conditions, when the Ge concentration of medium was 200 mg/L, the sporophore biomass of Cordyceps militaris was the maximum; and when Ge concentration was 300 mg/L,the amount of biotransformation of PG in sporophore was the highest; and when the Ge concentration is 250 mg/L, conversion rate of organic germanium (OG) in sporophore reached the highest value. In the liquid culture conditions, when the Ge concentration was 250 mg/L, the mycelium biomass of Cordyceps militaris was the maximum; and when Ge concentration was 150 mg/L, the amount of organic conversion of PG in mycelium was the most; and conversion rate of OG in mycelium was the highest in media with the Ge concentration of 200 mg/L. This study showed the germanium concentrations in 150 - 300 mg/L was more suitable for Ge accumulation and biotransformation of PG in Cordyceps militaris. In general, the biotransformation capacity to germanium of sporophore was stronger than that of mycelium of Cordyceps militaris. CONCLUSION: Germanium can significantly affect Ge accumulation and biotransformation of PG in Cordyceps militaris (P < 0.05) at different concentration. This result has practical value for Ge enriched cultivation of fruiting body in Cordyceps militaris.


Assuntos
Meios de Cultura/química , Germânio/metabolismo , Biomassa , Biotransformação , Cordyceps , Micélio
9.
Zhong Yao Cai ; 37(8): 1395-9, 2014 Aug.
Artigo em Chinês | MEDLINE | ID: mdl-25726649

RESUMO

OBJECTIVE: To study effects of blue light irradiation on monosaccharide composition of intracellular polysacchride and contents of cordycepin and cordyceps polysacchride of mycelium and sporocarp in Cordyceps militaris. METHODS: The monosaccharide composition of intracellular polysacchride of mycelium and sporocarp in Cordyceps militaris as materials were determined by gas chromatography after 144 h blue light irradiation. The contents of cordycepin and cordyceps polysacchride of mycelium and sporocarp in Cordyceps militaris were detected at different blue light irradiation periods. At the same time, the growth of mycelium and sporocarp in Cordyceps militaris were observed during blue light irradiation. RESULTS: Mycelium polysaccharide in Cordyceps militaris was a kind of heteropolysaccharide containing four kinds of monosaccharide and fruiting body polysaccharide was a kind of heteropolysaccharide containing five kinds of monosaccharide. Whether blue light irradiation or dark culture, the content changes of cordyceps polysacchride in two groups showed similar patterns in the test of mycelium polysaccharides. The content changes of cordyceps polysacchride in two groups were basically the same in the detection of sporocarp polysacchride. Cordycepin content in the two set of experiments of blue light irradiation all showed a clear upward trend in the detection of mycelium and sporocarp in Cordyceps militaris. CONCLUSION: The blue light irradiation has certain effect on the species and quantity of monosaccharide in intracellular polysaccharide. The content increase of cordycepin and cordyceps polysacchride in Cordyceps militaris are promoted by blue light irradiation. Blue light can help the morphogenesis and promote the differentiation and growth of sporocarp in Cordyceps militaris. This study is the first report about the effect of blue light on the type and quantity of the monosaccharide composition in polysaccharide of Cordyceps militaris, which will lay the foundation for further study on the metabolism of active substance in Cordyceps militaris by blue light irradiation.


Assuntos
Cordyceps/química , Desoxiadenosinas/química , Monossacarídeos/química , Polissacarídeos/química , Espaço Extracelular/química , Luz , Micélio
10.
Hum Vaccin Immunother ; 9(7): 1430-7, 2013 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-23571172

RESUMO

Enterovirus 71 (EV71) is one of the major causative agents for hand, foot and mouth disease (HFMD) in childhood. Nowadays, HFMD or EV71 infections have already become an important public health issue throughout the world. Vaccination may be the most effective measure to control the transmission of the virus. Therefore, to pave EV71 vaccine into human clinical trial, in the present study a comprehensive preclinical safety assessment of inactivated EV71 vaccine including single- and repeat-dose toxicity studies were conducted in rats and cynomolgus monkeys. No abnormal findings were observed in rats following single intramuscular administration with EV71 vaccine (640 U). The results also showed no obvious systemic toxicities from four repetitive intramuscular injections, with a 14-d interval, of two dosages of EV71 vaccine in the two animal species. Antinuclear antibody response was not detected after the repeated administrations. Histopathological examination demonstrated the minimal to severe inflammatory changes in muscle tissues of the injection sites in EV71 vaccine-injected animals and most of findings have been improved over time. Furthermore, test article could induce highly EV71-specfic neutralizing antibody response in both animal species. Taken together, these data suggested a favorable safety profile for inactivated EV71 vaccine and supported this product to enter human phase I clinical trial.


Assuntos
Enterovirus Humano A/imunologia , Doença de Mão, Pé e Boca/imunologia , Doença de Mão, Pé e Boca/prevenção & controle , Vacinas Virais/efeitos adversos , Vacinas Virais/uso terapêutico , Animais , Anticorpos Antinucleares/sangue , Anticorpos Neutralizantes/sangue , Anticorpos Antivirais/sangue , Feminino , Macaca fascicularis , Masculino , Ratos , Ratos Wistar , Vacinas de Produtos Inativados/efeitos adversos , Vacinas de Produtos Inativados/imunologia , Vacinas de Produtos Inativados/uso terapêutico , Vacinas Virais/imunologia
11.
Chin J Cancer ; 29(7): 689-96, 2010 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-20591222

RESUMO

BACKGROUND AND OBJECTIVE: Previous studies have shown that Bmi-1 is overexpressed in a variety of tumors, suggesting that Bmi-1 plays an important role in tumorigenesis. In this study, we investigated the effect of Bim-1 siRNA on cell proliferation, cell cycle, cell apoptosis and migration of human esophageal carcinoma EC9706 cells, and explored its potential mechanisms. METHODS: Bmi-1 small interfering RNA (siRNA) was transferred into EC9706 cells. Then, cell proliferation was measured using cell counting kit-8 (CCK-8), cell cycle and cell apoptosis were analyzed by flow cytometry, cell migration ability was detected using Boyden chamber assay, and the mRNA and protein expression levels of Bmi-1, p16, Bcl-2, Bax, and MMP-2 were determined using real-time polymerase chain reaction (PCR) and Western blot analysis, respectively. RESULTS: Bmi-1 siRNA treatment significantly inhibited the expression of Bmi-1 at both mRNA and protein levels in EC9706 cells. Cell proliferation rate decreased dramatically in the Bmi-1 siRNA treated group than in the untreated group and in the scrambled siRNA treated group (both P < 0.001). In Bmi-1 treated group, the percentage of cells at G(0)/G(1) stage was 71.93%, which was higher than that in the untreated group (47.36%) or scramble siRNA treated group (48.47%) (both P < 0.001). Early cell apoptosis rate also increased significantly in the Bmi-1 siRNA treated group (both 17.32%) than in the untreated group (2.61%) and in the scramble siRNA treated group (2.73%) (both P < 0.001). Further experiment suggested that downregulation of Bmi-1 led to less cell migration. In EC9706 cells transfected by Bmi-1 siRNA, the expression levels of p16 and Bax increased, while the expression level of Bcl-2 decreased. CONCLUSIONS: Bmi-1 downregulation in esophageal carcinoma cells inhibits cell proliferation, cell cycle, and cell migration, while increases cell apoptosis. These results suggest that Bmi-1 is a potential molecular target of treating esophageal cancer.


Assuntos
Apoptose , Ciclo Celular , Movimento Celular , Neoplasias Esofágicas , Proteínas Nucleares/metabolismo , Proteínas Proto-Oncogênicas/metabolismo , RNA Interferente Pequeno/genética , Proteínas Repressoras/metabolismo , Linhagem Celular Tumoral , Proliferação de Células , Inibidor p16 de Quinase Dependente de Ciclina/metabolismo , Regulação para Baixo , Neoplasias Esofágicas/metabolismo , Neoplasias Esofágicas/patologia , Regulação Neoplásica da Expressão Gênica , Humanos , Proteínas Nucleares/genética , Proteínas Nucleares/fisiologia , Complexo Repressor Polycomb 1 , Proteínas Proto-Oncogênicas/genética , Proteínas Proto-Oncogênicas/fisiologia , Proteínas Proto-Oncogênicas c-bcl-2/metabolismo , RNA Mensageiro/metabolismo , Proteínas Repressoras/genética , Proteínas Repressoras/fisiologia , Transfecção , Proteína X Associada a bcl-2/metabolismo
12.
Eur J Pharmacol ; 592(1-3): 123-7, 2008 Sep 11.
Artigo em Inglês | MEDLINE | ID: mdl-18627770

RESUMO

Clozapine, an atypical antipsychotic, is very effective in the treatment of resistant schizophrenia. However, cardiotoxicity of clozapine, particularly in young patients, has raised concerns about its safety. Increased catecholamines have been postulated to trigger an inflammatory response resulting in myocarditis, dilated cardiomyopathy, and death, although this has not yet been thoroughly studied. Here, we used the mouse to study whether clozapine administration could cause adverse myocarditis associated with an increase in catecholamines. Male Balb/C mice, age ~6 weeks, were administered 5, 10 or 25 mg/kg clozapine daily for 7 and 14 days; one group was administered 25 mg/kg clozapine plus 2 mg/kg propranolol for 14 days. Saline-treated mice served as controls. Heart sections were stained with hematoxylin and eosin for histopathological examination. Plasma catecholamines were measured with HPLC. Myocardial TNF-alpha concentrations were determined by ELISA. Histopathology of clozapine-treated mice showed a significant dose-related increase in myocardial inflammation that correlated with plasma catecholamine levels and release of TNF-alpha. Propranolol significantly attenuated these effects. A hypercatecholaminergic state induced by clozapine could explain the occurrence of myocarditis in some patients. Our data suggest that a beta-adrenergic blocking agent may be effective in reducing the incidence and severity of clozapine-induced myocarditis.


Assuntos
Antipsicóticos/toxicidade , Catecolaminas/fisiologia , Clozapina/toxicidade , Miocardite/induzido quimicamente , Miocardite/metabolismo , Antagonistas Adrenérgicos beta/farmacologia , Animais , Citocinas/metabolismo , Ensaio de Imunoadsorção Enzimática , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Miocardite/patologia , Miocárdio/metabolismo , Miocárdio/patologia , Propranolol/farmacologia , Fator de Necrose Tumoral alfa/metabolismo
13.
Pflugers Arch ; 452(3): 268-75, 2006 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-16715295

RESUMO

The present study was designed to determine whether cardiac inflammation is important for the successful homing of stem cells to the heart after intravenous injection in a murine myocarditis model. Male Bagg albino/c mice were infected with encephalomyocarditis virus (EMCV) to produce myocarditis. Subgroups of mice received single injections by tail vein of embryonic stem cells (ESCs) transfected with green fluorescent protein (GFP) as a marker at days 3, 14, or 60 after infection; other subgroups without stem cell injections were killed at each of these time points to assess the degree of inflammation present. The surviving mice were killed at day 90 after virus infection and hemodynamics, gross pathology, histology, and inflammatory cytokine production in the hearts were measured. Our results indicate that myocardial inflammation was most severe and cytokine production highest at day 14 after EMCV inoculation, and in particular, was strongly positive for interleukin 6. Mice receiving intravenous ESC injections on day 14 after EMCV inoculation showed the largest number of GFP-positive cells at the time of death and the greatest functional improvement compared to uninfected controls without inflammation. We conclude that factors released from myocardium during inflammation are important for enhancing the homing, migration, and implantation of systemically infused stem cells.


Assuntos
Citocinas/metabolismo , Células-Tronco Embrionárias/fisiologia , Coração/fisiologia , Miocardite/fisiopatologia , Transplante de Células-Tronco/métodos , Animais , Proteínas de Fluorescência Verde , Injeções Intravenosas , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Miocardite/patologia , Miocárdio/patologia , Necrose
14.
Am J Physiol Heart Circ Physiol ; 289(4): H1577-83, 2005 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-15923319

RESUMO

Recent studies point to important interactions between proinflammatory cytokines and neurohumoral mediators in heart failure. Here we investigate the influence of the beta-adrenergic system on cytokines and neurohumoral factors and the sequelae of viral myocarditis. In an experimental model with virus-infected BALB/c mice, we studied the acute and chronic effects of epinephrine and propranolol on myocardial morphology, cytokine gene expression, and survival. BALB/c mice were inoculated with the encephalomyocarditis virus (EMCV) or sham inoculated with saline and followed for 30 days. Epinephrine increased the severity of inflammatory cell infiltration and myocardial necrosis induced by EMCV. Gene expression of TNF-alpha, IL-6, and IL-10 was markedly enhanced by epinephrine in EMCV-inoculated mice. Survival rate after 30 days was reduced to 40% in epinephrine-treated EMCV-inoculated mice compared with 70% in untreated EMCV-inoculated mice (P < 0.05). Treatment with the beta-blocker propranolol significantly decreased mortality, myocardial necrosis, and infiltration of inflammatory cells in EMCV-inoculated mice. Propranolol also suppressed gene expression of TNF-alpha, IL-6, and IL-10. A single dose of epinephrine 120 days after EMCV inoculation caused sudden death in 70% of infected mice; propranolol significantly reduced incidence of death to 33%. These results indicate that acute and chronic stages of viral myocarditis are modulated by the beta-adrenergic system and its interactions with proinflammatory cytokines.


Assuntos
Agonistas Adrenérgicos/farmacologia , Antagonistas Adrenérgicos beta/farmacologia , Infecções por Cardiovirus/tratamento farmacológico , Vírus da Encefalomiocardite , Epinefrina/farmacologia , Miocardite/tratamento farmacológico , Propranolol/farmacologia , Doença Aguda , Âmnio/citologia , Animais , Arritmias Cardíacas/virologia , Infecções por Cardiovirus/imunologia , Infecções por Cardiovirus/mortalidade , Doença Crônica , Citocinas/genética , Morte Súbita Cardíaca/prevenção & controle , Expressão Gênica/imunologia , Humanos , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Miocardite/mortalidade , Miocardite/virologia
15.
J Surg Res ; 121(1): 20-4, 2004 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-15313370

RESUMO

BACKGROUND: Sepsis and endotoxemia frequently complicate the care of surgical patients. Basic and clinical investigations have correlated tumor necrosis factor alpha (TNF) levels with myocardial suppression and lethality after sepsis. Soluble TNF receptor 1 (sTNFRI) is an endogenous mechanism of clearing serum TNF. Elucidating mechanisms of endogenous adaptation may allow the development of novel therapeutic strategies. Endotoxin tolerance (LPS-preconditioning) is associated with a down-regulation of proinflammatory monokine production; thus, similar down-regulation of sTNFRI may be expected. However, it may be equally plausible to hypothesize that the processes which lead to enhanced shedding of these receptors are up-regulated during tolerance. MATERIALS AND METHODS: To study this, sublethal LPS was administered to male rats (Salmonella typhimurium, 500 microg/kg IP in 1 ml bacteriostatic normal saline IP) or an equivalent volume of bacteriostatic normal saline IP (sham) 24 h prior to subsequent LPS challenge. Rats were sacrificed at 0, 1, 2, 4, 6, and 24 h following LPS and serum TNF and TNFRI were measured by ELISAs. RESULTS: LPS induced a significant increase in sTNFRI at 1, 2, 4, and 6 h following LPS. sTNFRI levels returned to baseline by 24 h following LPS treatment. LPS induced a parallel increase in TNF. LPS pretreatment (preconditioning) resulted in a significant increase in TNFRI and a significant decrease in TNF. CONCLUSION: This study constitutes the initial demonstration that tolerance mechanisms: (1) up-regulate sTNFRI, which binds and clears TNF; and (2) reverses the TNF-to-sTNFRI ratio. Safe pharmacologic methods of up-regulating endogenous TNF-clearance mechanisms may ultimately have therapeutic value.


Assuntos
Antígenos CD/efeitos dos fármacos , Lipopolissacarídeos/farmacologia , Receptores do Fator de Necrose Tumoral/efeitos dos fármacos , Animais , Antígenos CD/sangue , Masculino , Ratos , Ratos Sprague-Dawley , Receptores do Fator de Necrose Tumoral/sangue , Receptores Tipo I de Fatores de Necrose Tumoral , Fatores de Tempo , Fator de Necrose Tumoral alfa/análise , Regulação para Cima
16.
Eur J Pharmacol ; 471(1): 41-7, 2003 Jun 13.
Artigo em Inglês | MEDLINE | ID: mdl-12809951

RESUMO

The present study was designed to investigate the effects of dantrolene on intracellular Ca(2+) ([Ca(2+)](i)) handling and inotropy in rat infarcted myocardium. Dantrolene-treated rats with myocardial infarction were placed into two different dosage groups. The infarcted control group received placebo only. Isometric contractility and intracellular Ca(2+) transients were recorded simultaneously in isolated papillary muscles. Diastolic [Ca(2+)](i) was significantly lower in muscle preparations from infarcted rats receiving dantrolene compared to the placebo control group. Additionally, treatment with dantrolene in infarcted rats significantly improved the inotropic response to 10(-4) M isoproterenol. The protein levels of the sarcoplasmic reticulum Ca(2+) ATPase were increased in infarcted rat hearts with dantrolene treatment. We conclude that dantrolene improved the inotropic response to beta-adrenoceptor stimulation in rat postinfarcted myocardium, which is related to improved intracellular Ca(2+) handling, and lowered diastolic Ca(2+) concentration.


Assuntos
Cálcio/metabolismo , Dantroleno/farmacocinética , Contração Miocárdica/efeitos dos fármacos , Infarto do Miocárdio/tratamento farmacológico , Animais , Western Blotting , Proteínas de Ligação ao Cálcio/química , Proteínas de Ligação ao Cálcio/metabolismo , ATPases Transportadoras de Cálcio/química , ATPases Transportadoras de Cálcio/metabolismo , Ciclofilinas/química , Ciclofilinas/metabolismo , Dantroleno/administração & dosagem , Ventrículos do Coração/química , Ventrículos do Coração/metabolismo , Injeções Intraperitoneais , Contração Isométrica/efeitos dos fármacos , Masculino , Infarto do Miocárdio/patologia , Tamanho do Órgão/efeitos dos fármacos , Ratos , Ratos Endogâmicos Lew , ATPases Transportadoras de Cálcio do Retículo Sarcoplasmático , Fatores de Tempo
18.
Can J Physiol Pharmacol ; 80(10): 1015-21, 2002 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-12450069

RESUMO

Cocaine has been shown to depress myocardial function, which may be linked to abnormal Ca2+ handling by the sarcoplasmic reticulum (SR). To examine whether cocaine affects Ca(2+)-handling proteins and myocardial performance, we injected BALB/c mice with cocaine daily (30 mg/kg, i.p.) for 14 d. Sarcoplasmic reticulum Ca(2+)-ATPase (SERCA2a) levels, phospholamban (PLB) protein levels, and hemodynamic parameters were measured. After cocaine exposure, myocardial function was significantly decreased both in vivo and in vitro. Also, SERCA2a protein levels were significantly decreased in all cocaine-treated hearts (p < 0.05 compared with saline control). Normalized SERCA2a levels were 1.2 +/- 0.2 (densitometric units) in the cocaine groups (p < 0.05 compared with saline control). However, there was no statistical difference in PLB protein levels between the cocaine and the saline groups. In isolated papillary muscle studies, cocaine did not block the response to extracellular Ca2+ but it did prolong the relaxation time of the muscle. These results indicate that cocaine does not block extracellular Ca2+ entrance across the cell membrane, but that it decreases SERCA2a protein levels. In conclusion, our study demonstrates that cocaine decreases SERCA2a protein levels and depresses myocardial function.


Assuntos
ATPases Transportadoras de Cálcio/metabolismo , Cocaína/farmacologia , Função Ventricular Esquerda/efeitos dos fármacos , Animais , Cálcio/metabolismo , Proteínas de Ligação ao Cálcio/metabolismo , Regulação para Baixo , Hemodinâmica/efeitos dos fármacos , Técnicas In Vitro , Contração Isométrica/efeitos dos fármacos , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Miocárdio/metabolismo , ATPases Transportadoras de Cálcio do Retículo Sarcoplasmático
19.
Am J Physiol Heart Circ Physiol ; 283(6): H2466-71, 2002 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-12388257

RESUMO

We monitored myocardial function in postinfarcted wild-type (WT) and transgenic (TG) mouse hearts with overexpression of the cardiac Na(+)/Ca(2+) exchanger. Five weeks after infarction, cardiac function was better maintained in TG than WT mice [left ventricular (LV) systolic pressure: WT, 41 +/- 2; TG, 58 +/- 3 mmHg; P < 0.05; maximum rising rate of LV pressure (+dP/dt(max)): WT, 3,750 +/- 346; TG, 5,075 +/- 334 mmHg/s; P < 0.05]. The isometric contractile response to beta-adrenergic stimulation was greater in papillary muscles from TG than WT mice (WT, 13.2 +/- 0.9; TG, 16.3 +/- 1.0 mN/mm(2) at 10(-4) M isoproterenol). The sarcoplasmic reticulum (SR) Ca(2+) content investigated by rapid cooling contractures in papillary muscles was greater in TG than WT mouse hearts. We conclude that myocardial function is better preserved in TG mice 5 wk after infarction, which results from enhanced SR Ca(2+) content via overexpression of the Na(+)/Ca(2+) exchanger.


Assuntos
Expressão Gênica , Infarto do Miocárdio/fisiopatologia , Trocador de Sódio e Cálcio/biossíntese , Disfunção Ventricular Esquerda/prevenção & controle , Agonistas Adrenérgicos beta/farmacologia , Animais , Cálcio/metabolismo , Modelos Animais de Doenças , Progressão da Doença , Eletrocardiografia , Frequência Cardíaca/efeitos dos fármacos , Frequência Cardíaca/genética , Hemodinâmica/efeitos dos fármacos , Hemodinâmica/genética , Heterozigoto , Técnicas In Vitro , Isoproterenol/farmacologia , Camundongos , Camundongos Transgênicos , Contração Miocárdica/efeitos dos fármacos , Contração Miocárdica/genética , Infarto do Miocárdio/complicações , Miocárdio/metabolismo , Retículo Sarcoplasmático/metabolismo , Trocador de Sódio e Cálcio/genética , Disfunção Ventricular Esquerda/complicações , Disfunção Ventricular Esquerda/diagnóstico
20.
Exp Biol Med (Maywood) ; 227(8): 632-8, 2002 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-12192106

RESUMO

The present study investigated whether genistein, a broad-spectrum tyrosine kinase inhibitor, could increase the myofilament Ca(2+) sensitivity and partially reverse postischemic depressed myocardial function. Left ventricular papillary muscles were isolated from adult Wistar rats and loaded with the Ca2+ indicator, aequorin. The use of fluorocarbon immersion with hypoxia simulated a model of ischemia. Myofilament responsiveness to Ca2+ was evaluated from force-[Ca2+]i relationship recorded during tetani in papillary muscles. Protein levels of troponin I (TnI) were measured in postischemic papillary muscles with the Western blot technique. Isometric contraction was depressed during the period of ischemia and remained low after 60 min of reoxygenation without a corresponding significant change of peak [Ca2+]i in the control group (n = 7). In contrast, the depression of isometric contraction was ameliorated during ischemia in muscle preparations in the presence of genistein (2 micro M; n = 8), and postischemic depressed myocardial contractility partially recovered after a 60-min reperfusion. The myofilament Ca2+ responsiveness was significantly increased in papillary muscles in the presence of genistein. Protein levels of TnI were reduced in postischemic papillary muscles, whereas genistein partially restored decreased protein levels of TnI. Our results reveal that genistein produces an effective attenuation of postischemic depressed myocardial function and improves myofibrillar Ca2+ responsiveness in rat myocardium.


Assuntos
Citoesqueleto de Actina/efeitos dos fármacos , Cálcio/farmacologia , Inibidores Enzimáticos/farmacologia , Genisteína/farmacologia , Proteínas Musculares/antagonistas & inibidores , Isquemia Miocárdica/complicações , Miocárdio Atordoado/fisiopatologia , Músculos Papilares/efeitos dos fármacos , Proteínas Tirosina Quinases/antagonistas & inibidores , Citoesqueleto de Actina/fisiologia , Equorina/farmacologia , Animais , Hipóxia Celular , Polímeros de Fluorcarboneto/farmacologia , Fluorcarbonetos , Contração Isométrica/efeitos dos fármacos , Masculino , Contração Miocárdica/efeitos dos fármacos , Miocárdio Atordoado/etiologia , Músculos Papilares/fisiologia , Ratos , Ratos Wistar , Troponina I/metabolismo
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