RESUMO
BACKGROUND: Prophylactic administration of mesenchymal stromal cells (MSCs) derived from adipose (AD-MSC) and bone marrow tissue (BM-MSC) in ovalbumin-induced asthma hinders inflammation in a Treg-dependent manner. It is uncertain whether MSCs act through Tregs when inflammation is already established in asthma induced by a clinically relevant allergen. OBJECTIVE: Evaluate the effect of therapeutic administration of MSCs on inflammation and Treg cells in house dust mite (HDM)-induced asthma. METHODS: BM-MSCs and AD-MSCs were administered intratracheally to C57BL/6 mice 1 day after the last HDM challenge. Lung function, remodelling and parenchymal inflammation were assayed 3 or 7 days after MSCs treatment, through invasive plethysmography and histology, respectively. Bronchoalveolar lavage fluid (BALF) and mediastinal lymph nodes (mLNs) were assessed regarding the inflammatory profile by flow cytometry, ELISA and qRT-PCR. MSCs were studied regarding their potential to induce Treg cells from primed and unprimed lymphocytes in vitro. RESULTS: BM-MSCs, but not AD-MSCs, reduced lung influx of eosinophils and B cells and increased IL-10 levels in HDM-challenged mice. Neither BM-MSCs nor AD-MSCs reduced lung parenchymal inflammation, airway hyperresponsiveness or mucus hypersecretion. BM-MSCs and AD-MSCs did not up-regulate Treg cell counts within the airways and mLNs, but BM-MSCs decreased the pro-inflammatory profile of alveolar macrophages. Co-culture of BM-MSCs and AD-MSCs with allergen-stimulated lymphocytes reduced Treg cell counts in a cell-to-cell contact-independent manner, although co-culture of both MSCs with unprimed lymphocytes up-regulated Treg cell counts. CONCLUSIONS: MSCs therapeutically administered exert anti-inflammatory effects in the airway of HDM-challenged mice, but do not ameliorate lung function or remodelling. Although MSC pre-treatment can increase Treg cell numbers, it is highly unlikely that the MSCs will induce Treg cell expansion when lymphocytes are allergenically primed in an established lung inflammation.
Assuntos
Asma/imunologia , Asma/terapia , Imunomodulação , Transplante de Células-Tronco Mesenquimais , Células-Tronco Mesenquimais/metabolismo , Linfócitos T Reguladores/imunologia , Alérgenos/imunologia , Animais , Asma/diagnóstico , Asma/metabolismo , Biópsia , Comunicação Celular , Técnicas de Cocultura , Modelos Animais de Doenças , Ativação Linfocitária/imunologia , Camundongos , Camundongos Transgênicos , Pyroglyphidae/imunologia , Testes de Função Respiratória , Linfócitos T Reguladores/metabolismoRESUMO
Experimental studies have reported that aerobic exercise after asthma induction reduces lung inflammation and remodeling. Nevertheless, no experimental study has analyzed whether regular/moderate aerobic training before the induction of allergic asthma may prevent these inflammatory and remodeling processes. For this purpose, BALB/c mice (n = 96) were assigned into non-trained and trained groups. Trained animals ran on a motorized treadmill at moderate intensity, 30 min/day, 3 times/week, for 8 weeks, and were further randomized into subgroups to undergo ovalbumin sensitization and challenge or receive saline using the same protocol. Aerobic training continued until the last challenge. Twenty-four hours after challenge, compared to non-trained animals, trained mice exhibited: (a) increased systolic output and left ventricular mass on echocardiography; (b) improved lung mechanics; (c) decreased smooth muscle actin expression and collagen fiber content in airways and lung parenchyma; (d) decreased transforming growth factor (TGF)-ß levels in bronchoalveolar lavage fluid (BALF) and blood; (e) increased interferon (IFN)-γ in BALF and interleukin (IL)-10 in blood; and (f) decreased IL-4 and IL-13 in BALF. In conclusion, regular/moderate aerobic training prior to allergic asthma induction reduced inflammation and remodeling, perhaps through increased IL-10 and IFN-γ in tandem with decreased Th2 cytokines.
Assuntos
Remodelação das Vias Aéreas , Asma/imunologia , Citocinas/imunologia , Pulmão/imunologia , Condicionamento Físico Animal , Animais , Asma/induzido quimicamente , Líquido da Lavagem Broncoalveolar/imunologia , Imuno-Histoquímica , Inflamação , Interferon gama/imunologia , Interleucina-10/imunologia , Interleucina-13/imunologia , Interleucina-4/imunologia , Pulmão/patologia , Pulmão/ultraestrutura , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Microscopia Eletrônica de Transmissão , Ovalbumina/efeitos adversos , Pneumonia/induzido quimicamente , Pneumonia/imunologia , Pneumonia/patologia , Fator de Crescimento Transformador beta/imunologiaRESUMO
BACKGROUND AND PURPOSE: Asthma is characterized by chronic lung inflammation and airway hyperresponsiveness. Despite recent advances in understanding of its pathophysiology, asthma remains a major public health problem, and new therapeutic strategies are urgently needed. In this context, we sought to ascertain whether treatment with the TK inhibitor dasatinib might repair inflammatory and remodelling processes, thus improving lung function, in a murine model of asthma. EXPERIMENTAL APPROACH: Animals were sensitized and subsequently challenged, with ovalbumin (OVA) or saline. Twenty-four hours after the last challenge, animals were treated with dasatinib, dexamethasone, or saline, every 12 h for 7 consecutive days. Twenty-four hours after the last treatment, the animals were killed, and data were collected. Lung structure and remodelling were evaluated by morphometric analysis, immunohistochemistry, and transmission electron microscopy of lung sections. Inflammation was assessed by cytometric analysis and ELISA, and lung function was evaluated by invasive whole-body plethysmography. KEY RESULTS: In OVA mice, dasatinib, and dexamethasone led to significant reductions in airway hyperresponsiveness. Dasatinib was also able to attenuate alveolar collapse, contraction index, and collagen fibre deposition, as well as increasing elastic fibre content, in OVA mice. Concerning the inflammatory process, dasatinib reduced inflammatory cell influx to the airway and lung-draining mediastinal lymph nodes, without inducing the thymic atrophy promoted by dexamethasone. CONCLUSIONS AND IMPLICATIONS: In this model of allergic asthma, dasatinib effectively blunted the inflammatory and remodelling processes in asthmatic lungs, enhancing airway repair and thus improving lung mechanics.
Assuntos
Remodelação das Vias Aéreas/efeitos dos fármacos , Asma/tratamento farmacológico , Dasatinibe/farmacologia , Pulmão/efeitos dos fármacos , Proteínas Tirosina Quinases/antagonistas & inibidores , Animais , Anti-Inflamatórios/farmacologia , Anti-Inflamatórios/uso terapêutico , Asma/imunologia , Asma/patologia , Asma/fisiopatologia , Dasatinibe/uso terapêutico , Dexametasona/farmacologia , Dexametasona/uso terapêutico , Feminino , Inflamação/tratamento farmacológico , Inflamação/imunologia , Inflamação/fisiopatologia , Pulmão/patologia , Pulmão/fisiopatologia , Camundongos Endogâmicos BALB C , Ovalbumina/imunologiaRESUMO
We investigated the effects of acute hypercapnic acidosis and buffered hypercapnia on lung inflammation and apoptosis in experimental acute lung injury (ALI). Twenty-four hours after paraquat injection, 28 Wistar rats were randomized into four groups (n=7/group): (1) normocapnia (NC, PaCO2=35-45 mmHg), ventilated with 0.03%CO2+21%O2+balancedN2; (2) hypercapnic acidosis (HC, PaCO2=60-70 mmHg), ventilated with 5%CO2+21%O2+balancedN2; and (3) buffered hypercapnic acidosis (BHC), ventilated with 5%CO2+21%O2+balancedN2 and treated with sodium bicarbonate (8.4%). The remaining seven animals were not mechanically ventilated (NV). The mRNA expression of interleukin (IL)-6 (p=0.003), IL-1ß (p<0.001), and type III procollagen (PCIII) (p=0.001) in lung tissue was more reduced in the HC group in comparison with NC, with no significant differences between HC and BHC. Lung and kidney cell apoptosis was reduced in HC and BHC in comparison with NC and NV. In conclusion, in this experimental ALI model, hypercapnia, regardless of acidosis, reduced lung inflammation and lung and kidney cell apoptosis.
Assuntos
Acidose , Lesão Pulmonar Aguda/fisiopatologia , Apoptose , Hipercapnia , Pneumonia/fisiopatologia , Doença Aguda , Animais , Soluções Tampão , Modelos Animais de Doenças , Concentração de Íons de Hidrogênio , Marcação In Situ das Extremidades Cortadas , Ratos , Ratos Wistar , Reação em Cadeia da Polimerase em Tempo Real , Reação em Cadeia da Polimerase Via Transcriptase ReversaRESUMO
Diabetes mellitus is a serious health problem that can lead to several pathological complications in numerous organs and tissues. The most important and most prevalent organs affected by this disease are the heart and the kidneys, and these complications are the major causes of death in patients with diabetes. MicroRNAs (miRNAs), short non-coding RNAs, have been found to be functionally important in the regulation of several pathological processes, and they are emerging as an important therapeutic tool to avoid the complications of diabetes mellitus. This review summarizes the knowledge on the effects of miRNAs in diabetes. The use of miRNAs in diabetes from a clinical perspective is also discussed, focusing on their potential role to repair cardiovascular and renal complications.
Assuntos
Cardiomiopatias Diabéticas/terapia , Retinopatia Diabética/terapia , Terapia Genética/métodos , Rim/metabolismo , MicroRNAs/metabolismo , Miocárdio/metabolismo , Animais , Cardiomiopatias Diabéticas/genética , Cardiomiopatias Diabéticas/metabolismo , Retinopatia Diabética/genética , Retinopatia Diabética/metabolismo , Regulação da Expressão Gênica , Marcadores Genéticos , Humanos , Oligonucleotídeos Antissenso/uso terapêutico , Interferência de RNARESUMO
We evaluated whether isoflurane, halothane and sevoflurane attenuate the inflammatory response and improve lung morphofunction in experimental asthma. Fifty-six BALB/c mice were sensitised and challenged with ovalbumin and anaesthetised with isoflurane, halothane, sevoflurane or pentobarbital sodium for one hour. Lung mechanics and histology were evaluated. Gene expression of pro-inflammatory (tumour necrosis factor-α), pro-fibrogenic (transforming growth factor-ß) and pro-angiogenic (vascular endothelial growth factor) mediators, as well as oxidative process modulators, were analysed. These modulators included nuclear factor erythroid-2 related factor 2, sirtuin, catalase and glutathione peroxidase. Isoflurane, halothane and sevoflurane reduced airway resistance, static lung elastance and atelectasis when compared with pentobarbital sodium. Sevoflurane minimised bronchoconstriction and cell infiltration, and decreased tumour necrosis factor-α, transforming growth factor-ß, vascular endothelial growth factor, sirtuin, catalase and glutathione peroxidase, while increasing nuclear factor erythroid-2-related factor 2 expression. Sevoflurane down-regulated inflammatory, fibrogenic and angiogenic mediators, and modulated oxidant-antioxidant imbalance, improving lung function in this model of asthma.
Assuntos
Anestésicos Inalatórios/uso terapêutico , Asma/tratamento farmacológico , Anestésicos Inalatórios/farmacologia , Animais , Asma/fisiopatologia , Broncoconstrição/efeitos dos fármacos , Pulmão/fisiopatologia , Camundongos , Camundongos Endogâmicos BALB CRESUMO
Morphology of extant felids is regarded as highly conservative. Most previous studies have focussed on skull morphology, so a vacuum exists about morphofunctional variation in postcranium and its role in structuring ensembles of felids in different continents. The African felid ensemble is particularly rich in ecologically specialized felids. We studied the ecomorphology of this ensemble using 31 cranial and 93 postcranial morphometric variables measured in 49 specimens of all 10 African species. We took a multivariate approach controlling for phylogeny, with and without body size correction. Postcranial and skull + postcranial analyses (but not skull-only analyses) allowed for a complete segregation of species in morphospace. Morphofunctional factors segregating species included body size, bite force, zeugopodial lengths and osteological features related to parasagittal leg movement. A general gradient of bodily proportions was recovered: lightly built, long-legged felids with small heads and weak bite forces vs. the opposite. Three loose groups were recognized: small terrestrial felids, mid-to-large sized scansorial felids and specialized Acinonyx jubatus and Leptailurus serval. As predicted from a previous study, the assembling of the African felid ensemble during the Plio-Pleistocene occurred by the arrival of distinct felid lineages that occupied then vacant areas of morphospace, later diversifying in the continent.
Assuntos
Ecossistema , Felidae/anatomia & histologia , Fósseis , Esqueleto , África , Animais , FilogeniaRESUMO
Microcystins (MCYSTs) are very stable cyclic peptidic toxins produced by cyanobacteria. Their effects on hepatic tissue have been studied extensively, and they are considered to be a potent hepatotoxin. However, several effects of MCYST on other organs have also been described, but generally in studies using higher doses of MCYST. In the present work, we investigated the effect of a single sublethal dose of MCYST-LR (55 µg/kg) in Wistar rats and analyzed different aspects that influenced renal physiology, including toxin accumulation, excretion, histological morphology, biochemical responses and oxidative damage in the kidney. After 24 h of exposure to MCYST-LR, it was possible to observe an increased glomerular filtration rate (6.28 ± 1.56 vs 2.16 ± 0.48 µl/min per cm(2)) compared with the control group. Increase of interstitial space and collagen deposition corresponded to a fibrotic response to the increased production of reactive oxygen species. The observed decrease of Na(+) reabsorption was due to inhibition of the activity of both Na(+) pumps in proximal tubules cells. We suggested that this modulation is mediated by the effect of MCYST as a phosphatase protein inhibitor that maintains the sustained kinase-mediated regulatory phosphorylation of the ATPases. The observed alteration of Na(+) active transporters lead to damage of renal function, since are involved in regulation of water and solute reabsorption in proximal tubules. The results of this report reinforce the importance of understanding the molecular effects of a single sublethal dose of MCYST-LR, which, in this study, was responsible for macro-alterations found in the renal parenchyma and renal physiology in rats.
Assuntos
Toxinas Bacterianas/toxicidade , Cianobactérias/química , Rim/efeitos dos fármacos , Microcistinas/toxicidade , Animais , Glutationa/metabolismo , Rim/metabolismo , Rim/patologia , Masculino , Toxinas Marinhas , Ratos , Ratos Wistar , Espécies Reativas de Oxigênio/metabolismo , ATPase Trocadora de Sódio-Potássio/metabolismoRESUMO
OBJECTIVE: To determine the epidemiological profile of malignant melanoma cases treated at the National Institute for Neoplastic Diseases "Dr. Eduardo Caceres Graziani" (INEN) over the period 1952 to 2008. STUDY DESIGN: All clinical records with complete data of patients presenting a histopathological diagnosis of malignant melanoma of the oral cavity were reviewed. Data such as age, gender, location, tumor size, disease length, presence of metastasis, treatment received and year of admission were recorded. RESULTS: During the study period 97 cases were found. The average age of patients was 52.85±1.6 years old mostly between 50 and 59 years old; the predominant gender was the female. The most common location was the palate and there was 58.8% of cases with a tumor size bigger than or equal to 4 cm. The length of the disease in 38.1% of the cases was longer than a year and in great part of the cases (69.1%) there was no metastasis. The treatment of choice was the surgery plus radiotherapy in 38.1% of the cases. According to the admission date it was also noted that the number of cases is increasing. CONCLUSION: The results of this study demonstrate a late diagnosis and an increasing frequency of this neoplasia in the oral cavity.
Assuntos
Melanoma , Neoplasias Bucais , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Estudos Transversais , Feminino , Humanos , Masculino , Melanoma/diagnóstico , Melanoma/epidemiologia , Pessoa de Meia-Idade , Neoplasias Bucais/diagnóstico , Neoplasias Bucais/epidemiologia , Peru , Estudos Retrospectivos , Adulto JovemRESUMO
Gene therapy is an alternative treatment for genetic lung disease, especially monogenic disorders such as cystic fibrosis. Cystic fibrosis is a severe autosomal recessive disease affecting one in 2500 live births in the white population, caused by mutation of the cystic fibrosis transmembrane conductance regulator (CFTR). The disease is classically characterized by pancreatic enzyme insufficiency, an increased concentration of chloride in sweat, and varying severity of chronic obstructive lung disease. Currently, the greatest challenge for gene therapy is finding an ideal vector to deliver the transgene (CFTR) to the affected organ (lung). Adeno-associated virus is the most promising viral vector system for the treatment of respiratory disease because it has natural tropism for airway epithelial cells and does not cause any human disease. This review focuses on the basic properties of adeno-associated virus and its use as a vector for cystic fibrosis gene therapy.
Assuntos
Humanos , Adenovírus Humanos , Regulador de Condutância Transmembrana em Fibrose Cística/genética , Fibrose Cística/terapia , Terapia Genética/métodos , Vetores Genéticos/uso terapêutico , Adenovírus Humanos/classificação , Técnicas de Transferência de GenesRESUMO
Gene therapy is an alternative treatment for genetic lung disease, especially monogenic disorders such as cystic fibrosis. Cystic fibrosis is a severe autosomal recessive disease affecting one in 2500 live births in the white population, caused by mutation of the cystic fibrosis transmembrane conductance regulator (CFTR). The disease is classically characterized by pancreatic enzyme insufficiency, an increased concentration of chloride in sweat, and varying severity of chronic obstructive lung disease. Currently, the greatest challenge for gene therapy is finding an ideal vector to deliver the transgene (CFTR) to the affected organ (lung). Adeno-associated virus is the most promising viral vector system for the treatment of respiratory disease because it has natural tropism for airway epithelial cells and does not cause any human disease. This review focuses on the basic properties of adeno-associated virus and its use as a vector for cystic fibrosis gene therapy.
Assuntos
Adenovírus Humanos , Regulador de Condutância Transmembrana em Fibrose Cística/genética , Fibrose Cística/terapia , Terapia Genética/métodos , Vetores Genéticos/uso terapêutico , Adenovírus Humanos/classificação , Técnicas de Transferência de Genes , HumanosRESUMO
This study tests the hypothesis that bone marrow-derived mononuclear cell (BMDMC) therapy may reduce lung inflammation and fibrosis leading to an improvement in respiratory mechanics in a murine model of silicosis. 52 female C57BL/6 mice were randomly assigned into four groups. In the silica group (SIL), silica suspension (20 mg/50 µL in saline) was intratracheally instilled. In the control animals, 50 µL saline was administered intratracheally. At 1 h, the control and SIL groups were further randomised, receiving BMDMC (2×106 i.v. control-cell and SIL-cell) or saline (50 µL i.v. control and SIL). BMDMC were obtained from male donor mice. At day 15, lung mechanics, histology, and the presence of Y chromosome, interleukin (IL)-1ß, IL-1α, IL-1 receptor antagonist (IL-1RN), IL-1 receptor type 1, transforming growth factor (TGF)-ß and caspase-3 mRNA expressions in lung tissue were analysed. In the SIL-cell group, the fraction area of granuloma, the number of macrophages and the collagen fibre content were reduced, yielding improved lung mechanics. The presence of male donor cells in lung tissue was not confirmed using detection of Y chromosome DNA. Nevertheless, caspase-3, IL-1ß, IL-1α, IL-1RN and TGF-ß mRNA expression diminished after cell therapy. In conclusion, BMDMC acted on inflammatory and fibrogenic processes improving lung function through paracrine effects.
Assuntos
Monócitos/transplante , Fibrose Pulmonar/induzido quimicamente , Fibrose Pulmonar/terapia , Silicose/terapia , Animais , Caspase 3/análise , Feminino , Interleucina-1alfa/análise , Interleucina-1beta/análise , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Receptores de Interleucina-1/análise , Dióxido de Silício/toxicidade , Fator de Crescimento Transformador beta/análise , Cromossomo YRESUMO
We examined whether recruitment maneuvers (RMs) with gradual increase in airway pressure (RAMP) provide better outcome than continuous positive airway pressure (CPAP) in paraquat-induced acute lung injury (ALI). Wistar rats received saline intraperitoneally (0.5 mL, CTRL) or paraquat (15 mg/kg, ALI). Twenty-four hours later lung mechanics [static elastance, viscoelastic component of elastance, resistive, viscoelastic and total pressures] were determined before and after recruitment with 40cmH2O CPAP for 40s or 40-s-long slow increase in pressure up to 40cmH2O (RAMP) followed by 0 or 5 cmH2O PEEP. Fractional area of alveolar collapse and PCIII mRNA were determined. All mechanical parameters and the fraction area of alveolar collapse were higher in ALI compared to CTRL. Only RAMP-PEEP maneuver significantly improved lung mechanics and decreased PCIII mRNA expression (53%) compared with ALI, while both RMs followed by PEEP decreased alveolar collapse. In conclusion, in the present experimental ALI model, RAMP followed by 5cm H2O PEEP yields a better outcome.
Assuntos
Lesão Pulmonar Aguda/fisiopatologia , Pulmão/patologia , Respiração com Pressão Positiva/métodos , Recrutamento Neurofisiológico/fisiologia , Mecânica Respiratória/fisiologia , Lesão Pulmonar Aguda/induzido quimicamente , Lesão Pulmonar Aguda/metabolismo , Lesão Pulmonar Aguda/patologia , Análise de Variância , Animais , Colágeno Tipo III/genética , Colágeno Tipo III/metabolismo , Modelos Animais de Doenças , Regulação da Expressão Gênica , Pulmão/metabolismo , Medidas de Volume Pulmonar , Paraquat , RNA Mensageiro/metabolismo , Ratos , Ratos WistarRESUMO
This study investigated whether repeated administration of recombinant adeno-associated virus type 5 (rAAV5) to the airways induces inflammatory processes in the lungs of BALB/c-mice, with mechanical and histologic changes. Saline was instilled intratracheally in the control group, and rAAV5-green fluorescence protein (GFP) (4x10(11)particles) in the virus group (VR). These groups were subdivided into four subgroups: one dose analyzed 3 weeks later (VR1d3w) and two doses analyzed 1 (VR2d1w), 2 (VR2d2w) and 3 weeks (VR2d3w) after the second dose. Lung morphometry, mechanical parameters, airway responsiveness, rAAV5-GFP transduction and the expression of inflammatory cytokines were investigated. No significant differences in lung mechanics, airway responsiveness, and morphometry were observed. Re-administration of rAAV5 vector resulted in a decrease in GFP mRNA expression in the VR2d3w group. There was no evidence of inflammatory response or apoptosis in any group. rAAV5 did not induce an inflammatory process, mechanical or morphometric changes in the lungs. AAV5 may be an appropriate vector for lung gene therapy.
Assuntos
Terapia Genética/efeitos adversos , Vetores Genéticos/efeitos adversos , Pneumonia/etiologia , Pneumonia/patologia , Resistência das Vias Respiratórias , Análise de Variância , Animais , Apoptose , Modelos Animais de Doenças , Proteínas de Fluorescência Verde/genética , Marcação In Situ das Extremidades Cortadas , Masculino , Camundongos , Camundongos Endogâmicos BALB C , RNA Mensageiro/metabolismo , Mecânica Respiratória/fisiologia , Fatores de TempoRESUMO
Cystic fibrosis (CF) is a lethal autosomal recessive genetic disease caused by mutations in the CF transmembrane conductance regulator (CFTR). Mutations in the CFTR gene may result in a defective protein processing that leads to changes in function and regulation of this chloride channel. Despite of the expression of CFTR in the kidney, patients with CF do not present major renal dysfunction, but it is known that both the urinary excretion of proteins and renal capacity to concentrate and dilute urine are altered in these patients. CFTR mRNA is expressed in all nephron segments of rat and human, and this abundance is more prominent in renal cortex and outer medulla renal areas. CFTR protein was detected in apical surface of both proximal and distal tubules of rat kidney but not in the outer medullary collecting ducts. Studies have demonstrated that CFTR does not only transport Cl- but also ATP. ATP transport by CFTR could be involved in the control of other ion transporters such as Na+ (ENaC) and K+ (renal outer medullary potassium) channels, especially in TAL and CCD. In the kidney, CFTR also might be involved in the endocytosis of low-molecular-weight proteins by proximal tubules. This review is focused on the CFTR function and structure, its role in the renal physiology, and its modulation by hormones involved in the control of extracellular fluid volume.
RESUMO
Insulin receptor substrate-1 (IRS-1) is the main intracellular substrate for both insulin and insulin-like growth factor I (IGF-I) receptors and is critical for cell mitogenesis. Thyrotropin is able to induce thyroid cell proliferation through the cyclic AMP intracellular cascade; however, the presence of either insulin or IGF-I is required for the mitogenic effect of thyroid-stimulating hormone (TSH) to occur. The aim of the present study was to determine whether thyroid IRS-1 content is modulated by TSH in vivo. Strikingly, hypothyroid goitrous rats, which have chronically high serum TSH levels (control, C = 2.31 ± 0.28; methimazole (MMI) 21d = 51.02 ± 6.02 ng/mL, N = 12 rats), when treated with 0.03 percent MMI in drinking water for 21 days, showed significantly reduced thyroid IRS-1 mRNA content. Since goiter was already established in these animals by MMI for 21 days, we also evaluated IRS-1 expression during goitrogenesis. Animals treated with MMI for different periods of time showed a progressive increase in thyroid weight (C = 22.18 ± 1.21; MMI 5d = 32.83 ± 1.48; MMI 7d = 31.1 ± 3.25; MMI 10d = 33.8 ± 1.25; MMI 14d = 45.5 ± 2.56; MMI 18d = 53.0 ± 3.01; MMI 21d = 61.9 ± 3.92 mg, N = 9-15 animals per group) and serum TSH levels (C = 1.57 ± 0.2; MMI 5d = 9.95 ± 0.74; MMI 7d = 10.38 ± 0.84; MMI 10d = 17.72 ± 1.47; MMI 14d = 25.65 ± 1.23; MMI 18d = 35.38 ± 3.69; MMI 21d = 31.3 ± 2.7 ng/mL, N = 9-15 animals per group). Thyroid IRS-1 mRNA expression increased progressively during goitrogenesis, being significantly higher by the 14th day of MMI treatment, and then started to decline, reaching the lowest values by the 21st day, when a significant reduction was detected. In the liver of these animals, however, a significant decrease of IRS-1 mRNA was detected after 14 days of MMI treatment, a mechanism probably involved in the insulin resistance that occurs in hypothyroidism. The increase in IRS-1 expression during goitrogenesis may represent...
Assuntos
Animais , Masculino , Ratos , Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Bócio/metabolismo , Hipotireoidismo/metabolismo , Glândula Tireoide/citologia , Tireotropina/metabolismo , Proteínas Adaptadoras de Transdução de Sinal/efeitos dos fármacos , Bócio/induzido quimicamente , Hipotireoidismo/induzido quimicamente , Mitose , Metimazol/farmacologia , Ratos Wistar , Reação em Cadeia da Polimerase Via Transcriptase Reversa , RNA Mensageiro/análise , Glândula Tireoide/efeitos dos fármacos , Tireotropina/efeitos dos fármacosRESUMO
Insulin receptor substrate-1 (IRS-1) is the main intracellular substrate for both insulin and insulin-like growth factor I (IGF-I) receptors and is critical for cell mitogenesis. Thyrotropin is able to induce thyroid cell proliferation through the cyclic AMP intracellular cascade; however, the presence of either insulin or IGF-I is required for the mitogenic effect of thyroid-stimulating hormone (TSH) to occur. The aim of the present study was to determine whether thyroid IRS-1 content is modulated by TSH in vivo. Strikingly, hypothyroid goitrous rats, which have chronically high serum TSH levels (control, C = 2.31 +/- 0.28; methimazole (MMI) 21d = 51.02 +/- 6.02 ng/mL, N = 12 rats), when treated with 0.03% MMI in drinking water for 21 days, showed significantly reduced thyroid IRS-1 mRNA content. Since goiter was already established in these animals by MMI for 21 days, we also evaluated IRS-1 expression during goitrogenesis. Animals treated with MMI for different periods of time showed a progressive increase in thyroid weight (C = 22.18 +/- 1.21; MMI 5d = 32.83 +/- 1.48; MMI 7d = 31.1 +/- 3.25; MMI 10d = 33.8 +/- 1.25; MMI 14d = 45.5 +/- 2.56; MMI 18d = 53.0 +/- 3.01; MMI 21d = 61.9 +/- 3.92 mg, N = 9-15 animals per group) and serum TSH levels (C = 1.57 +/- 0.2; MMI 5d = 9.95 +/- 0.74; MMI 7d = 10.38 +/- 0.84; MMI 10d = 17.72 +/- 1.47; MMI 14d = 25.65 +/- 1.23; MMI 18d = 35.38 +/- 3.69; MMI 21d = 31.3 +/- 2.7 ng/mL, N = 9-15 animals per group). Thyroid IRS-1 mRNA expression increased progressively during goitrogenesis, being significantly higher by the 14th day of MMI treatment, and then started to decline, reaching the lowest values by the 21st day, when a significant reduction was detected. In the liver of these animals, however, a significant decrease of IRS-1 mRNA was detected after 14 days of MMI treatment, a mechanism probably involved in the insulin resistance that occurs in hypothyroidism. The increase in IRS-1 expression during goitrogenesis may represent an important event associated with the increased rate of cell mitosis promoted by TSH and indicates that insulin and IGF-I are important co-mitogenic factors in vivo, possibly acting through the activation of IRS-1.
Assuntos
Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Bócio/metabolismo , Hipotireoidismo/metabolismo , Glândula Tireoide/citologia , Tireotropina/metabolismo , Proteínas Adaptadoras de Transdução de Sinal/efeitos dos fármacos , Animais , Bócio/induzido quimicamente , Hipotireoidismo/induzido quimicamente , Proteínas Substratos do Receptor de Insulina , Masculino , Metimazol/farmacologia , Mitose , RNA Mensageiro/análise , Ratos , Ratos Wistar , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Glândula Tireoide/efeitos dos fármacos , Tireotropina/efeitos dos fármacosRESUMO
Physical forces affect both the function and phenotype of cells in the lung. Bronchial, alveolar, and other parenchymal cells, as well as fibroblasts and macrophages, are normally subjected to a variety of passive and active mechanical forces associated with lung inflation and vascular perfusion as a result of the dynamic nature of lung function. These forces include changes in stress (force per unit area) or strain (any forced change in length in relation to the initial length) and shear stress (the stress component parallel to a given surface). The responses of cells to mechanical forces are the result of the cell's ability to sense and transduce these stimuli into intracellular signaling pathways able to communicate the information to its interior. This review will focus on the modulation of intracellular pathways by lung mechanical forces and the intercellular signaling. A better understanding of the mechanisms by which lung cells transduce physical forces into biochemical and biological signals is of key importance for identifying targets for the treatment and prevention of physical force-related disorders.
Assuntos
Pulmão/fisiologia , Mecanorreceptores/fisiologia , Mecanotransdução Celular/fisiologia , Matriz Extracelular/fisiologia , Humanos , Junções Intercelulares/fisiologia , Membranas Intracelulares/fisiologia , Pulmão/citologia , Estresse MecânicoRESUMO
Physical forces affect both the function and phenotype of cells in the lung. Bronchial, alveolar, and other parenchymal cells, as well as fibroblasts and macrophages, are normally subjected to a variety of passive and active mechanical forces associated with lung inflation and vascular perfusion as a result of the dynamic nature of lung function. These forces include changes in stress (force per unit area) or strain (any forced change in length in relation to the initial length) and shear stress (the stress component parallel to a given surface). The responses of cells to mechanical forces are the result of the cell's ability to sense and transduce these stimuli into intracellular signaling pathways able to communicate the information to its interior. This review will focus on the modulation of intracellular pathways by lung mechanical forces and the intercellular signaling. A better understanding of the mechanisms by which lung cells transduce physical forces into biochemical and biological signals is of key importance for identifying targets for the treatment and prevention of physical force-related disorders.
Assuntos
Humanos , Pulmão/fisiologia , Mecanorreceptores/fisiologia , Mecanotransdução Celular/fisiologia , Matriz Extracelular/fisiologia , Junções Intercelulares/fisiologia , Membranas Intracelulares/fisiologia , Pulmão/citologia , Estresse MecânicoRESUMO
The cystic fibrosis transmembrane conductance regulator (CFTR) is one of the most intensively investigated Cl- channels. Different mutations in the CFTR gene cause the disease cystic fibrosis (CF). CFTR is expressed in the apical membrane of various epithelial cells including the intestine. The major organ affected in CF patients is the lung, but it also causes an important dysfunction of intestinal ion transport. The modulation of CFTR mRNA expression by atrial natriuretic peptide (ANP) was investigated in rat proximal colon and in human intestinal CaCo-2 cells by RNase protection assay and semi-quantitative reverse transcriptase PCR techniques. Groups of rats subjected to volume expansion or intravenous infusion of synthetic ANP showed respective increases of 60 and 50% of CFTR mRNA expression in proximal colon. CFTR mRNA was also increased in cells treated with ANP, reaching a maximum effect at 10(-9) M ANP, probably via cGMP. ANP at 10(-9) M was also able to stimulate both the CFTR promoter region (by luciferase assay) and protein expression in CaCo-2 cells (by Western blot and immunoprecipitation/phosphorylation). These results suggested the involvement of ANP, a hormone involved with extracellular volume, in the expression of CFTR in rat proximal colon and CaCo-2 intestinal cells.