RESUMO
Highly reversible Mg battery chemistry demands a suitable electrolyte formulation highly compatible with currently available electrodes. In general, conventional electrolytes form a passivation layer on the Mg anode, requiring the use of MgCl2 additives that lead to severe corrosion of cell components and low anodic stability. Herein, for the first time, we conducted a comparative study of a series of Mg halides as potential electrolyte additives in conventional magnesium bis(hexamethyldisilazide)-based electrolytes. A novel electrolyte formulation that includes MgBr2 showed unprecedented performance in magnesium plating/stripping, with an average Coulombic efficiency of 99.26% over 1000 cycles at 0.5 mA/cm2 and 0.5 mAh/cm2. Further analysis revealed the in situ formation of a robust Mg anode-electrolyte interface, which leads to dendrite-free Mg deposition and stable cycling performance in a Mg-Mo6S8 battery over 100 cycles. This study demonstrates the rational formulation of a novel MgBr2-based electrolyte with high anodic stability of 3.1 V for promising future applications.
RESUMO
Lithium-sulfur batteries (LSBs) are known to be potential next-generation energy storage devices. Recently, our group reported an LSB cathode made using sulfur spheres that has been spherically templated by MXene nanosheets decorated with CoSe2 nanoparticles, forming a "loose-templating" configuration. It was postulated that the minimal restacking of the outer nanoparticle-decorated MXene layer helps to enable facile ionic transport. However, as the nanosheets do not adhere conformally to the internal sphere's surface, such a configuration can be controversial, thus requiring a more systematic understanding. In this work, we report and quantify for the first time the independent and dependent variables involved in this morphology, allowing us to identify that having smaller nanoparticles resulted in better Li+ ion transport and enhanced electrochemical performances. The optimized cathode structure exhibited an initial specific capacity of 1274 mAh/g and a 0.06% decay rate per cycle at 0.5 C over 1000 cycles in LSBs.
RESUMO
Rechargeable magnesium batteries (RMBs) have been proposed as a promising alternative to currently commercialized lithium-ion batteries. However, Mg anode passivation in conventional electrolytes necessitates the use of highly corrosive Cl- ions in the electrolyte. Herein for the first time, we design a chloride-free electrolyte for RMBs with magnesium bis(hexamethyldisilazide) (Mg(HMDS)2) and magnesium triflate (Mg(OTf)2) as the main salts and tetrabutylammonium triflate (TBAOTf) as an additive. The TBAOTf additive improved the dissolution of Mg salts, consequently enhancing the charge-carrying species in the electrolyte. COMSOL studies further revealed desirable Mg growth in our modulated electrolyte, substantiated by homogeneous electric flux distribution across the electrolyte-electrode interface. Post-mortem chemical composition analysis uncovered a MgF2-rich solid electrolyte interphase (SEI) that facilitated exceptional Mg deposition/dissolution reversibility. Our study illustrates a highly promising strategy for synthesizing a corrosion-free and reversible Mg battery electrolyte with a widened anodic stability window of up to 4.43 V.
RESUMO
Two-dimensional metal dichalcogenides have demonstrated outstanding potential as cathodes for magnesium-ion batteries. However, the limited capacity, poor cycling stability, and severe electrode pulverization, resulting from lack of void space for expansion, impede their further development. In this work, we report for the first time, nickel sulfide (NiS2) hollow nanospheres assembled with nanoparticles for use as cathode materials in magnesium-ion batteries. Notably, the nanospheres were prepared by a one-step solvothermal process in the absence of an additive. The results show that regulating the synergistic effect between the rich anions and hollow structure positively affects its electrochemical performance. Crystallographic and microstructural characterizations reveal the reversible anionic redox of S2-/(S2)2-, consistent with density functional theory results. Consequently, the optimized cathode (8-NiS2 hollow nanospheres) could deliver a large capacity of 301 mA h g-1 after 100 cycles at 50 mA g-1, supporting the promising practical application of NiS2 hollow nanospheres in magnesium-ion batteries.
RESUMO
Metallic magnesium is a promising high-capacity anode material for energy storage technologies beyond lithium-ion batteries. However, most reported Mg metal anodes are only cyclable under shallow cycling (≤1 mAh cm-2) and thus poor Mg utilization (<3%) conditions, significantly compromising their energy-dense characteristic. Herein, composite Mg metal anodes with high capacity utilization of 75% are achieved by coating magnesiophilic gold nanoparticles on copper foils for the first time. Benefiting from homogeneous ionic flux and uniform deposition morphology, the Mg-plated Au-Cu electrode exhibits high average Coulombic efficiency of 99.16% over 170 h cycling at 75% Mg utilization. Moreover, the full cell based on Mg-plated Au-Cu anode and Mo6S8 cathode achieves superior capacity retention of 80% after 300 cycles at a low negative/positive ratio of 1.33. This work provides a simple yet effective general strategy to enhance Mg utilization and reversibility, which can be extended to other metal anodes as well.
RESUMO
Two-dimensional MXenes produce competitive performances when incorporated into lithium-sulfur batteries (LSBs), solving key problems such as the poor electronic conductivity of sulfur and dissolution of its polysulfide intermediates. However, MXene nanosheets are known to easily aggregate and restack during electrode fabrication, filtration, or water removal, limiting their practical applicability. Furthermore, in complex electrocatalytic reactions like the multistep sulfur reduction process in LSBs, MXene alone is insufficient to ensure an optimal reaction pathway. In this work, we demonstrate for the first time a loose templating of sulfur spheres using Ti3C2Tx MXene nanosheets decorated with polymorphic CoSe2 nanoparticles. This work shows that the templating of sulfur spheres using nanoparticle-decorated MXene nanosheets can prevent nanosheet aggregation and exert a strong electrocatalytic effect, thereby enabling improved reaction kinetics and battery performance. The S@MXene-CoSe2 cathode demonstrated a long cycle life of 1000 cycles and a low capacity decay rate of 0.06% per cycle in LSBs.
RESUMO
Owing to its high volumetric capacity and natural abundance, magnesium (Mg) metal has attracted tremendous attention as an ideal anode material for rechargeable Mg batteries. Despite Mg deposition playing an integral role in determining the cycling lifespan, its exact behavior is not clearly understood yet. Herein, for the first time, we introduce a facile approach to build magnesiophilic In/MgIn sites in situ on a Mg metal surface using InCl3 electrolyte additive for rechargeable Mg batteries. These magnesiophilic sites can regulate Mg deposition behaviors by homogenizing the distributions of Mg-ion flux and electric field at the electrode-electrolyte interphase, allowing flat and compact Mg deposition to inhibit short-circuiting. The as-designed Mg metal batteries achieve a stable cycling lifespan of 340 h at 1.0 mA cm-2 and 1.0 mAh cm-2 using Celgard separators, while the full cell coupled with Mo6S8 cathode maintains a high capacity retention of 95.5% over 800 cycles at 1 C.
RESUMO
Lithium-sulfur (Li-S) batteries suffer from sluggish sulfur redox reactions under high-sulfur-loading and lean-electrolyte conditions. Herein, a typical Co@NC heterostructure composed of Co nanoparticles and a semiconductive N-doped carbon matrix is designed as a model Mott-Schottky catalyst to exert the electrocatalytic effect on sulfur electrochemistry. Theoretical and experimental results reveal the redistribution of charge and a built-in electric field at the Co@NC heterointerface, which are critical to lowering the energy barrier of polysulfide reduction and Li2S oxidation in the discharge and charge process, respectively. With Co@NC Mott-Schottky catalysts, the Li-S batteries display an ultrahigh capacity retention of 92.1% and a system-level gravimetric energy density of 307.8 Wh kg-1 under high S loading (10.73 mg cm-2) and lean electrolyte (E/S = 5.9 µL mgsulfur-1) conditions. The proposed Mott-Schottky heterostructure not only deepens the understanding of the electrocatalytic effect in Li-S chemistry but also inspires a rational catalyst design for advanced high-energy-density batteries.
RESUMO
Stress response refers to the systemic nonspecific response upon exposure to strong stimulation or chronic stress, such as severe trauma, shock, infection, burn, major surgery or improper environment, which disturb organisms and damage their physical and psychological health. However, the pathogenesis of stress induced disorder remains complicated and diverse under different stress exposure. Recently, studies have revealed a specific role of microRNAs (miRNAs) in regulating cellular function under different types of stress, suggesting a significant role in the treatment and prevention of stress-related diseases, such as stress ulcer, posttraumatic stress disorder, stress-induced cardiomyopathy and so on. This paper have reviewed the literature on microRNA related stress diseases in different databases including PubMed, Web of Science, and the MiRbase. It considers only peer-reviewed papers published in English between 2004 and 2018. This review summarizes new advances in principles and mechanisms of miRNAs regulating stress signalling pathway and the role of miRNAs in human stress diseases. This comprehensive review is to provide an integrated account of how different stresses affect miRNAs and how stress-miRNA pathways may, in turn, be linked with disease, which offers some potential strategies for stress disorder treatment. Furthermore, the limitation of current studies and challenges for clinical use are discussed.
Assuntos
MicroRNAs/fisiologia , Estresse Fisiológico/genética , Animais , Humanos , MicroRNAs/biossínteseRESUMO
It has been found that Helicobacter pylori ï¼H. pyloriï¼is not only the main cause of gastric cancer, but also closely related to its metastasis. E-cadherin cleavage induced by matrix metalloproteinases (MMPs) plays an important role in the tumor metastasis. In the present study, we investigated the role of microRNAs-MMPs-E-cadherin in migration and invasion of gastric cancer cells treated with H. pylori. The results showed that H. pylori induced migration and invasion of SGC-7901 cells with a down-regulation of E-cadherin expression, which were abolished by MMPs knock down, E-cadherin overexpression, mimics of miR128 and miR148a. MiR128/miR148a inhibitors restored MMP-3/MMP-7 expression, down-regulated E-cadherin level, and accelerated cellular migration and invasion. This study suggests that H. pylori induces migration and invasion of gastric cancer cells through reduction of E-cadherin function by activation of MMP-3, -â¯7. The present results also suggest that the activated MMPs/E-cadherin pathway is related with down-regulation of miR128/miR148a in the human gastric cancer cells infected with H. pylori.
Assuntos
Caderinas/metabolismo , Helicobacter pylori , Metaloproteinases da Matriz Secretadas/fisiologia , MicroRNAs/fisiologia , Neoplasias Gástricas/microbiologia , Linhagem Celular Tumoral , Movimento Celular/efeitos dos fármacos , Humanos , Metaloproteinase 3 da Matriz/fisiologia , Metaloproteinase 7 da Matriz/fisiologia , Inibidores de Metaloproteinases de Matriz/farmacologia , MicroRNAs/antagonistas & inibidores , Invasividade Neoplásica , Neoplasias Gástricas/enzimologia , Neoplasias Gástricas/genética , Neoplasias Gástricas/metabolismoRESUMO
We have found that eIF3a plays an important role in bleomycin-induced pulmonary fibrosis, and up-regulation of eIF3a induced by TGF-ß1 is mediated via the ERK1/2 pathway. Whether ERK1/2 - eIF3a signal pathway is involved in calcitonin gene-related peptide (CGRP)-mediated pathogenesis of bleomycin-induced pulmonary fibrosis remains unknown. Pulmonary fibrosis was induced by intratracheal instillation of bleomycin (5 mg/kg) in rats. Primary pulmonary fibroblasts were cultured to investigate the proliferation by BrdU incorporation method and flow cytometry. Sensory CGRP depletion by capsaicin exacerbated bleomycin-induced pulmonary fibrosis in rats, as shown by a significant disturbed alveolar structure, marked thickening of the interalveolar septa and dense interstitial infiltration by inflammatory cells and fibroblasts, accompanied with increased expression of TGF-ß1, eIF3a, phosphorylated ERK1/2, α-SMA, collagen I, and collagen III. Exogenous application of CGRP significantly inhibited TGF-ß1-induced proliferation and differentiation of pulmonary fibroblasts concomitantly with decreased expression of eIF3a, phosphorylated ERK1/2, α-SMA, collagen I, and collagen III. These effects of CGRP were abolished in the presence of CGRP8-37. These results suggest that endogenous CGRP is related to the development of pulmonary fibrosis induced by bleomycin, and the inhibitory effect of CGRP on proliferation of lung fibroblasts involves the ERK1/2 - eIF3a signaling pathway.
Assuntos
Bleomicina/toxicidade , Peptídeo Relacionado com Gene de Calcitonina/metabolismo , Peptídeo Relacionado com Gene de Calcitonina/farmacologia , Regulação para Baixo/efeitos dos fármacos , Fibrose Pulmonar/induzido quimicamente , Fibrose Pulmonar/metabolismo , Animais , Antibióticos Antineoplásicos/toxicidade , Peptídeo Relacionado com Gene de Calcitonina/uso terapêutico , Células Cultivadas , Regulação para Baixo/fisiologia , Fibroblastos/efeitos dos fármacos , Fibroblastos/metabolismo , Masculino , Fibrose Pulmonar/tratamento farmacológico , Distribuição Aleatória , Ratos , Ratos Sprague-DawleyRESUMO
The risk of cardiovascular complications in diabetic patients is mainly associated with endothelial dysfunction. Reduced number of EPCs and impaired function of EPCs in diabetes result in imbalance of endothelial homeostasis and dysfunction of vessels. In patients with diabetes mellitus, plasma levels of asymmetric dimethylarginine (ADMA) were elevated, while the expression and activity of dimethylarginine dimethylaminohydrolase (DDAH) were reduced. In the present study, we investigated the role of the DDAH2/ADMA pathway in the senescence of EPCs in type 2 diabetic patients and cultured EPCs treated with high glucose. The results showed that the percentage of senescent EPCs increased while the expression of DDAH2 decreased concomitantly with an increase in the plasma levels of ADMA in patients with type 2 diabetes mellitus (T2DM). Similar results were seen in cultured EPCs treated with high glucose. Exogenous application of ADMA accelerated the senescence of EPCs in a dose-dependent manner, and overexpression of DDAH2 inhibited high glucose-induced EPCs senescence. In addition, it has also been reported that DDAH/ADMA pathway is regulated by silent information regulator 1 (SIRT1) in endothelial cell. In the present study, we found decreased expression of SIRT1 both in T2DM patients and EPCs pretreated with high glucose. And resveratrol (activating SIRT1) inhibited high glucose-induced EPCs senescence by upregulating the expression of DDAH2 and decreasing the levels of ADMA. Taken together, we concluded that DDAH2/ADMA is involved in the accelerated senescence of EPCs in diabetes, which is associated with the activation of SIRT1.
Assuntos
Amidoidrolases/metabolismo , Arginina/análogos & derivados , Diabetes Mellitus Tipo 2/enzimologia , Diabetes Mellitus Tipo 2/patologia , Células Progenitoras Endoteliais/patologia , Arginina/sangue , Arginina/metabolismo , Senescência Celular , Diabetes Mellitus Tipo 2/sangue , Diabetes Mellitus Tipo 2/metabolismo , Células Progenitoras Endoteliais/metabolismo , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Sirtuína 1/metabolismoRESUMO
Recent studies demonstrated that NADPH oxidase 2 (NOX2) expression in myocardium after ischemia-reperfusion (IR) is significantly upregulated. However, the underlying mechanisms remain unknown. This study aims to determine if nuclear cardiac myosin light chain 2 (MYL2), a well-known regulatory subunit of myosin, functions as a transcription factor to promote NOX2 expression following myocardial IR in a phosphorylation-dependent manner. We examined the phosphorylation status of nuclear MYL2 (p-MYL2) in a rat model of myocardial IR (left main coronary artery subjected to 1 h ligation and 3 h reperfusion) injury, which showed IR injury and upregulated NOX2 expression as expected, accompanied by elevated H2O2 and nuclear p-MYL2 levels; these effects were attenuated by inhibition of myosin light chain kinase (MLCK). Next, we explored the functional relationship of nuclear p-MYL2 with NOX2 expression in H9c2 cell model of hypoxia-reoxygenation (HR) injury. In agreement with our in vivo findings, HR treatment increased apoptosis, NOX2 expression, nuclear p-MYL2 and H2O2 levels, and the increases were ameliorated by inhibition of MLCK or knockdown of MYL2. Finally, molecular biology techniques including co-immunoprecipitation (Co-IP), chromatin immunoprecipitation (ChIP), DNA pull-down and luciferase reporter gene assay were utilized to decipher the molecular mechanisms. We found that nuclear p-MYL2 binds to the consensus sequence AGCTCC in NOX2 gene promoter, interacts with RNA polymerase II and transcription factor IIB to form a transcription preinitiation complex, and thus activates NOX2 gene transcription. Our results demonstrate that nuclear MYL2 plays an important role in IR injury by transcriptionally upregulating NOX2 expression to enhance oxidative stress in a phosphorylation-dependent manner.
Assuntos
Miosinas Cardíacas/fisiologia , Glicoproteínas de Membrana/genética , Miocárdio/metabolismo , Cadeias Leves de Miosina/fisiologia , NADPH Oxidases/genética , Animais , Miosinas Cardíacas/análise , Núcleo Celular/química , Células Cultivadas , Masculino , Traumatismo por Reperfusão Miocárdica/prevenção & controle , Cadeias Leves de Miosina/análise , Quinase de Cadeia Leve de Miosina/antagonistas & inibidores , NADPH Oxidase 2 , Estresse Oxidativo , Fosforilação , Ratos , Ratos Sprague-DawleyRESUMO
Large-dose or long-term use of aspirin tends to cause gastric mucosa injury, which is recognized as the major side effect of aspirin. It has been demonstrated that glutamate exerts a protective effect on stomach, and the level of glutamate is critically controlled by cystine/glutamate transporter (Xc(-)). In the present study, we investigated the role of glutamate-cystine/glutamate transporter system in aspirin-induced acute gastric mucosa injury in vitro and in vivo. Results showed that in human gastric epithelial cells, aspirin incubation increased the activity of LDH and the number of apoptotic cells, meanwhile down-regulated the mRNA expression of Xc(-) accompanied with decreased glutamate release. Similar results were seen in a rat model. In addition, exogenous l-glutamate attenuated the gastric mucosa injury and cell damage induced by aspirin both in vitro and in vivo. Taken together, our results demonstrated that acute gastric mucosa injury induced by aspirin is related to reduction of glutamate-cystine/glutamate transporter system activity.
Assuntos
Sistema X-AG de Transporte de Aminoácidos/metabolismo , Sistema y+ de Transporte de Aminoácidos/metabolismo , Aspirina/administração & dosagem , Mucosa Gástrica/metabolismo , Ácido Glutâmico/metabolismo , Úlcera Gástrica/induzido quimicamente , Úlcera Gástrica/metabolismo , Animais , Anti-Inflamatórios não Esteroides , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Relação Dose-Resposta a Droga , Mucosa Gástrica/efeitos dos fármacos , Mucosa Gástrica/patologia , Humanos , Masculino , Ratos , Ratos Sprague-DawleyRESUMO
Endothelial progenitor cells (EPCs) are involved in the repair of vessels and angiogenesis and are useful in the treatment of ischemic diseases. The dimethylarginine dimethylaminohydrolase (DDAH)/asymmetric dimethylarginine (ADMA) pathway is regulated by silent information regulator 1 (SIRT1), leading to the senescence of endothelial cells (ECs). Here, we demonstrated that peripheral blood EPCs predominantly expressed DDAH2 that increased with EPC differentiation. EPC senescence and dysfunction were induced on interruption of DDAH2 expression, whereas the mRNA expression of vascular endothelial growth factor (VEGF) and kinase-domain insert containing receptor (KDR) were downregulated. Moreover, SIRT1 expression increased with EPC differentiation. Interruption of SIRT1 inhibited DDAH2, VEGF, and KDR expression, but had no effect on the level of ADMA. From our data, we concluded that DDAH2 is involved in the differentiation of EPCs and regulates the senescence and function of EPCs through the VEGF/KDR pathway by activation of SIRT1.
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Amidoidrolases/metabolismo , Arginina/análogos & derivados , Diferenciação Celular/efeitos dos fármacos , Células Progenitoras Endoteliais/efeitos dos fármacos , Amidoidrolases/antagonistas & inibidores , Amidoidrolases/genética , Arginina/farmacologia , Células Cultivadas , Senescência Celular , Células Progenitoras Endoteliais/citologia , Células Progenitoras Endoteliais/metabolismo , Humanos , Interferência de RNA , RNA Mensageiro/metabolismo , RNA Interferente Pequeno/metabolismo , Sirtuína 1/genética , Sirtuína 1/metabolismo , Fator A de Crescimento do Endotélio Vascular/genética , Fator A de Crescimento do Endotélio Vascular/metabolismo , Receptor 2 de Fatores de Crescimento do Endotélio Vascular/genética , Receptor 2 de Fatores de Crescimento do Endotélio Vascular/metabolismoRESUMO
The aim of this study was to investigate whether N-arachidonic acid ethanolamine (anandamide, AEA) transporter contributed to calcitonin gene-related peptide (CGRP) expression mediated by nitroglycerin (GTN) in peripheral blood mononuclear cells (PBMCs) of healthy volunteers and its association with the mitochondrial aldehyde dehydrogenase-2 (ALDH2) Glu504Lys (ALDH2*2) polymorphism. In 10 ALDH2*2-genotyped Chinese volunteers, we assessed the activity of AEA transporter and expression of CGRP messenger ribonucleic acid (mRNA) in cultured PBMCs treated with different concentration of GTN with or without pretreatment with AM404 (the AEA transporter blocker). In this study, the activity of AEA transporter and expression of CGRP mRNA elevated with the increase in the concentration of GTN. Pretreatment of the cells with AM404 (1 µM) 2 hours before GTN reduced the GTN-induced increase in both AEA transporter activity and CGRP mRNA expression significantly, and cells with the ALDH2*1/*1 homozygote genotype showed significantly higher activity of AEA transporter and CGRP mRNA expression than carriers of the ALDH2*2 allele. Therefore, we strongly suggested that GTN can stimulate CGRP expression by elevating the AEA transporter activity, which is affected by ALDH2 Glu504Lys polymorphism.
Assuntos
Aldeído Desidrogenase/genética , Ácidos Araquidônicos/metabolismo , Peptídeo Relacionado com Gene de Calcitonina/genética , Endocanabinoides/metabolismo , Proteínas de Membrana Transportadoras/metabolismo , Alcamidas Poli-Insaturadas/metabolismo , Adulto , Aldeído-Desidrogenase Mitocondrial , Ácidos Araquidônicos/farmacologia , Povo Asiático/genética , Regulação da Expressão Gênica/efeitos dos fármacos , Genótipo , Humanos , Leucócitos Mononucleares/metabolismo , Masculino , Nitroglicerina/farmacologia , Polimorfismo Genético , RNA Mensageiro/metabolismoRESUMO
Fluorofenidone (AKF-PD) is a novel pyridone derivate that targets transforming growth factor-ß1 (TGF-ß1) signaling. Previous studies have proven that AKF-PD functions as an antifibrotic agent in pulmonary fibrosis and renal fibrosis models. Activated TGF-ß1 signaling is thought to be a major feature of pulmonary hypertension (PH). TGF-ß1 exerts powerful pro-proliferation effects on pulmonary arterial smooth muscle cells (PASMCs), and hence, prompts vascular remodeling. This study is designed to investigate the effect of AKF-PD on vascular remodeling in a rat model of hypoxia-induced PH. PH was induced in rats by 4 weeks of hypoxia. The expression of TGF-ß1, collagen I, and collagen III was analyzed by ELISA, immunohistochemistry, real-time PCR, or Western blot. Proliferation of cultured PASMCs was determined by the BrdU incorporation method and flow cytometry. The results showed that AKF-PD treatment (0.5 or 1.0 g·(kg body mass)·d(-1)) for 4 weeks attenuated pulmonary vascular remodeling and improved homodynamic parameters. TGF-ß1 level was significantly down-regulated by AKF-PD both in vivo and in vitro. Furthermore, hypoxia- and TGF-ß1-induced PASMC proliferation and collagen expression were both significantly suppressed by AKF-PD. These results suggest that AKF-PD ameliorates the progression of PH induced by hypoxia in rats through its regulation of TGF-ß1 expression, PASMC proliferation, and the extracellular matrix.
Assuntos
Hipertensão Pulmonar/patologia , Hipertensão Pulmonar/fisiopatologia , Hipóxia/metabolismo , Músculo Liso Vascular/efeitos dos fármacos , Piridonas/farmacologia , Animais , Proliferação de Células/efeitos dos fármacos , Células Cultivadas , Colágeno Tipo I/metabolismo , Colágeno Tipo II/metabolismo , Matriz Extracelular/metabolismo , Hemodinâmica/efeitos dos fármacos , Hipertensão Pulmonar/etiologia , Hipóxia/complicações , Pulmão/irrigação sanguínea , Pulmão/efeitos dos fármacos , Masculino , Músculo Liso Vascular/metabolismo , Músculo Liso Vascular/patologia , Artéria Pulmonar/efeitos dos fármacos , Artéria Pulmonar/patologia , Artéria Pulmonar/fisiopatologia , Ratos Sprague-Dawley , Fator de Crescimento Transformador beta1/metabolismoRESUMO
Asymmetric dimethylarginine (ADMA) is an endogenous inhibitor of nitric oxide synthase (NOS), which can be hydrolyzed by dimethylarginine-dimethylaminohydrolase (DDAH). It has been reported that adipocytes can produce DDAH/ADMA, but its role remains unknown. In the present study, we examined the effects of adipocyte-derived DDAH/ADMA on insulin sensitivity using animal and cell models. Results showed that in adipose tissue of high fat diet-fed diabetic rats, as well as in high glucose (25 mM) plus insulin (100 nM)-treated 3T3-L1 adipocytes, expression levels of insulin receptor substance-1 (IRS-1), glucose transporter-4 (GLUT-4), and DDAH isoform-2 (DDAH-2) were down-regulated compared with control, although DDAH-1 expression showed no significant changes. We also observed that nitric oxide bioavailability, DDAH and NOS activities were subsequently decreased, while the local ADMA content was elevated in diabetic adipose tissue. Transfection of human DDAH-2 gene into high glucose- and insulin-treated 3T3-L1 adipocytes significantly ameliorated DDAH activity, reduced ADMA contents, and up-regulated the mRNA expression levels of IRS-1 and GLUT-4. These findings suggested that in the development of type 2 diabetes mellitus, local DDAH-2 in adipocytes might play an important role in regulating insulin sensitivity.
Assuntos
Tecido Adiposo/enzimologia , Amidoidrolases/metabolismo , Diabetes Mellitus Experimental/fisiopatologia , Diabetes Mellitus Tipo 2/fisiopatologia , Resistência à Insulina , Células 3T3-L1 , Animais , Sequência de Bases , Primers do DNA , Diabetes Mellitus Experimental/enzimologia , Diabetes Mellitus Tipo 2/enzimologia , Masculino , Camundongos , Ratos , Ratos Sprague-Dawley , Reação em Cadeia da Polimerase em Tempo RealRESUMO
OBJECTIVE: To explore the inhibitory effect of calcitonin gene-related peptide (CGRP) on cardiac fibroblast proliferation and collagen synthesis induced by isoprenaline and the underlying mechanism. METHODS: The primary cultured cardiac fibroblasts were incubated with isoprenaline (10(-5) mol/L) for 48 h after pretreatment with CGRP (10(-8) or 10(-7) mol/L) for 1 h. Cell activity was detected by MTT. The mRNA expression of collagen (types I and III) and connective tissue growth factor (CTGF) was determined by RT-PCR, and the levels of intracellular ROS were determined by DCFH-DA fluorescent probe. RESULTS: Isoprenaline significantly promoted fibroblast proliferation and up-regulated collagen (types I and III) and CTGF mRNA expression concomitantly with an increase in ROS production, which were attenuated by CGRP. The effect of CGRP on cardiac fibroblasts was inhibited by CGRP8-37, a selective antagonist of CGRP receptor. CONCLUSION: CGRP is able to protect cardiac fibroblasts against isoprenaline-induced proliferation and collagen expression, which might be related to the down-regulation of CTGF expression through inhibition of ROS production.
Assuntos
Peptídeo Relacionado com Gene de Calcitonina/farmacologia , Proliferação de Células/efeitos dos fármacos , Fibroblastos/citologia , Isoproterenol/antagonistas & inibidores , Miócitos Cardíacos/citologia , Animais , Animais Recém-Nascidos , Células Cultivadas , Colágeno Tipo I/genética , Colágeno Tipo I/metabolismo , Colágeno Tipo III/genética , Colágeno Tipo III/metabolismo , Fator de Crescimento do Tecido Conjuntivo/genética , Fator de Crescimento do Tecido Conjuntivo/metabolismo , Isoproterenol/farmacologia , Cultura Primária de Células , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Ratos , Ratos Sprague-Dawley , Espécies Reativas de Oxigênio/metabolismoRESUMO
OBJECTIVE: To identify BSG single nucleotide polymorphisms (SNPs) in Chinese Han population. METHODS: Peripheral blood samples were collected from 48 unrelated healthy Chinese Han subjects. Sequences at the BSG locus, including the promoter region, all exons and exon-intron boundaries were amplified, sequenced and followed by Hardy-Weinberg equilibrium test and linkage disequilibrium (LD) analysis. RESULTS: A total of 19 SNPs were identified, 2 of which two were novel. Genotype distributions of all SNPs were consistent with Hardy-Weinberg equilibrium. Four haplotype blocks were constructed throughout the gene locus, and 9 haplotype tag SNPs (htSNPs) were inferred. Distribution of SNPs was in accordance with the neutrality theory in Chinese Han population. CONCLUSION: For the first time, systematic identification of BSG SNPs in the Chinese Han population has been done, and 9 htSNPs are identified. Our study has provided basis for further genetic association studies for related diseases as well as pharmacogenetics study for drug response in Chinese Han population.