RESUMO
Lower oxidative capacity in skeletal muscles (SKMs) is a prevailing cause of metabolic diseases. Exercise not only enhances the fatty acid oxidation (FAO) capacity of SKMs but also increases lactate levels. Given that lactate may contribute to tricarboxylic acid cycle (TCA) flux and impact monocarboxylate transporter 1 in the SKMs, we hypothesize that lactate can influence glucose and fatty acid (FA) metabolism. To test this hypothesis, we investigated the mechanism underlying lactate-driven FAO regulation in the SKM of mice with diet-induced obesity (DIO). Lactate was administered to DIO mice immediately after exercise for over 3 wk. We found that increased lactate levels enhanced energy expenditure mediated by fat metabolism during exercise recovery and decreased triglyceride levels in DIO mice SKMs. To determine the lactate-specific effects without exercise, we administered lactate to mice on a high-fat diet (HFD) for 8 wk. Similar to our exercise conditions, lactate increased FAO, TCA cycle activity, and mitochondrial respiration in the SKMs of HFD-fed mice. In addition, under sufficient FA conditions, lactate increased uncoupling protein-3 abundance via the NADH-NAD+ shuttle. Conversely, ATP synthase abundance decreased in the SKMs of HFD mice. Taken together, our results suggest that lactate amplifies the adaptive increase in FAO capacity mediated by the TCA cycle and mitochondrial respiration in SKMs under sufficient FA abundance.NEW & NOTEWORTHY Lactate administration post-exercise promotes triglyceride content loss in skeletal muscles (SKMs) and reduced body weight. Lactate enhances fatty acid oxidation in the SKMs of high-fat diet (HFD)-fed mice due to enhanced mitochondrial oxygen consumption. In addition, lactate restores the malate-aspartate shuttle, which is reduced by a HFD, and activates the tricarboxylic acid cycle (TCA) cycle in SKMs. Interestingly, supraphysiological lactate facilitates uncoupling protein-3 expression through NADH/NAD+, which is enhanced under high-fat levels in SKMs.
Assuntos
Ciclo do Ácido Cítrico , Ácidos Graxos , Ácido Láctico , Camundongos Endogâmicos C57BL , Músculo Esquelético , Obesidade , Oxirredução , Animais , Ácidos Graxos/metabolismo , Músculo Esquelético/metabolismo , Ciclo do Ácido Cítrico/efeitos dos fármacos , Ácido Láctico/metabolismo , Obesidade/metabolismo , Camundongos , Masculino , Metabolismo Energético , Dieta Hiperlipídica/efeitos adversos , Mitocôndrias Musculares/metabolismo , Camundongos Obesos , Condicionamento Físico Animal , Respiração Celular , Mitocôndrias/metabolismoRESUMO
Image segmentation plays a central role in a broad range of applications, such as medical image analysis, autonomous vehicles, video surveillance and augmented reality. Portrait segmentation, which is a subset of semantic image segmentation, is widely used as a preprocessing step in multiple applications such as security systems, entertainment applications, video conferences, etc. A substantial amount of deep learning-based portrait segmentation approaches have been developed, since the performance and accuracy of semantic image segmentation have improved significantly due to the recent introduction of deep learning technology. However, these approaches are limited to a single portrait segmentation model. In this paper, we propose a novel approach using an ensemble method by combining multiple heterogeneous deep-learning based portrait segmentation models to improve the segmentation performance. The Two-Models ensemble and Three-Models ensemble, using a simple soft voting method and weighted soft voting method, were experimented. Intersection over Union (IoU) metric, IoU standard deviation and false prediction rate were used to evaluate the performance. Cost efficiency was calculated to analyze the efficiency of segmentation. The experiment results show that the proposed ensemble approach can perform with higher accuracy and lower errors than single deep-learning-based portrait segmentation models. The results also show that the ensemble of deep-learning models typically increases the use of memory and computing power, although it also shows that the ensemble of deep-learning models can perform more efficiently than a single model with higher accuracy using less memory and less computing power.
RESUMO
Selenoprotein W (SelW) is a selenium-containing protein with a redox motif found abundantly in the skeletal muscle of rodents. Previous in vitro studies suggest that SelW plays an antioxidant role; however, relatively few in vivo studies have addressed the antioxidant role of SelW. Since oxidative stress is a causative factor for the development of insulin resistance in obese subjects, we hypothesized that if SelW plays a role as an antioxidant, SelW deficiency could aggravate the oxidative stress and insulin resistance caused by a high-fat diet. SelW deficiency did not affect insulin sensitivity and H2O2 levels in the skeletal muscle of control diet-fed mice. SelW levels in the skeletal muscle were decreased by high-fat diet feeding for 12 wk. High-fat diet induced obesity and insulin resistance and increased the levels of H2O2 and oxidative stress makers, which were not affected by SelW deficiency. High-fat diet feeding increased the expression of antioxidant enzymes; however, SelW deficiency did not affect the expression levels of antioxidants. These results suggest that SelW does not play a protective role against oxidative stress and insulin resistance in the skeletal muscle of high-fat diet-fed obese mice.
Assuntos
Dieta Hiperlipídica/efeitos adversos , Músculo Esquelético/metabolismo , Obesidade/genética , Estresse Oxidativo , Selenoproteína W/genética , Animais , Catalase/genética , Catalase/metabolismo , Regulação da Expressão Gênica , Teste de Tolerância a Glucose , Humanos , Peróxido de Hidrogênio/metabolismo , Resistência à Insulina , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Músculo Esquelético/patologia , Obesidade/etiologia , Obesidade/metabolismo , Obesidade/patologia , Selenoproteína W/deficiência , Superóxido Dismutase/genética , Superóxido Dismutase/metabolismo , Superóxido Dismutase-1/genética , Superóxido Dismutase-1/metabolismoRESUMO
Regulation of lipogenesis by pathophysiological factors in the liver and skeletal muscle is well understood; however, regulation in the kidney is still unclear. To elucidate nutritional regulation of lipogenic factors in the kidney, we measured the renal expression of lipogenic transcriptional factors and enzymes during fasting and refeeding in chow-fed and high-fat-fed mice. We also examined the regulatory effect of the liver X receptor (LXR) on the expression of lipogenic factors. The renal gene expression of sterol regulatory element-binding protein (SREBP)-1c and fatty acid synthase (FAS) was reduced by fasting for 48 h and restored by refeeding, whereas the mRNA levels of forkhead box O (FOXO)1/3 were increased by fasting and restored by refeeding. Accordingly, protein levels of SREBP-1, FAS, and phosphorylated FOXO1/3 were reduced by fasting and restored by refeeding. The patterns of lipogenic factors expression in the kidney were similar to those in the liver and skeletal muscle. However, this phasic regulation of renal lipogenic gene expression was blunted in diet-induced obese mice. LXR agonist TO901317 increased the lipogenic gene expression and the protein levels of SREBP-1 precursor and FAS but not nuclear SREBP-1. Moreover, increases in insulin-induced gene mRNA and nuclear carbohydrate-responsive element binding protein (ChREBP) levels were observed in the TO901317-treated mice. These results suggest that the kidney shows flexible suppression and restoration of lipogenic factors following fasting and refeeding in lean mice, but this is blunted in obese mice. LXR is involved in the renal expression of lipogenic enzymes, and ChREBP may mediate the response.
Assuntos
Jejum/metabolismo , Rim/enzimologia , Lipogênese , Receptores X do Fígado/metabolismo , Fatores de Transcrição/metabolismo , Animais , Fatores de Transcrição de Zíper de Leucina e Hélice-Alça-Hélix Básicos , Privação de Alimentos , Regulação da Expressão Gênica , Fígado/metabolismo , Receptores X do Fígado/agonistas , Masculino , Camundongos Endogâmicos C57BL , Músculo Esquelético/metabolismo , Proteínas Nucleares/metabolismo , Obesidade/metabolismoRESUMO
Differentiation of muscle satellite cells (MSCs) involves interaction of the proteins present in the extracellular matrix (ECM) with MSCs to regulate their activity, and therefore phenotype. Herein, we report fibromodulin (FMOD), a member of the proteoglycan family participating in the assembly of ECM, as a novel regulator of myostatin (MSTN) during myoblast differentiation. In addition to having a pronounced effect on the expression of myogenic marker genes [myogenin (MYOG) and myosin light chain 2 (MYL2)], FMOD was found to maintain the transcriptional activity of MSTN Moreover, coimmunoprecipitation and in silico studies performed to investigate the interaction of FMOD helped confirm that it antagonizes MSTN function by distorting its folding and preventing its binding to activin receptor type IIB. Furthermore, in vivo studies revealed that FMOD plays an active role in healing by increasing satellite cell recruitment to sites of injury. Together, these findings disclose a hitherto unrecognized regulatory role for FMOD in MSCs and highlight new mechanisms whereby FMOD circumvents the inhibitory effects of MSTN and triggers myoblast differentiation. These findings offer a basis for the design of novel MSTN inhibitors that promote muscle regeneration after injury or for the development of pharmaceutical agents for the treatment of different muscle atrophies.-Lee, E. J., Jan, A. T., Baig, M. H., Ashraf, J. M., Nahm, S.-S., Kim, Y.-W., Park, S.-Y., Choi, I. Fibromodulin: a master regulator of myostatin controlling progression of satellite cells through a myogenic program.
Assuntos
Fibromodulina/metabolismo , Miostatina/metabolismo , Células Satélites de Músculo Esquelético/fisiologia , Animais , Bovinos , Diferenciação Celular , Linhagem Celular , Colágeno , Fibromodulina/genética , Regulação da Expressão Gênica/fisiologia , Técnicas de Silenciamento de Genes , Marcadores Genéticos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Desenvolvimento Muscular/fisiologia , Atrofia Muscular/metabolismo , Mioblastos/fisiologia , Miostatina/genéticaRESUMO
Irregularities in the cellular uptake of thyroid hormones significantly affect muscle development and regeneration. Herein, we report indispensable role of transthyretin (TTR) in maintaining cellular thyroxine level. TTR was found to enhance recruitment of muscle satellite cells to the site of injury, thereby regulating muscle regeneration. Fluorescence-activated cell sorting (FACS) and immunofluorescence analysis of TTRwt (TTR wild type) and TTRkd (TTR knock-down) cells revealed that TTR controlled cell cycle progression by affecting the expression of Cyclin A2. Deiodinase 2 (D2) mediated increases in triiodothyronine levels were found to regulate the expression of myogenic marker, myogenin (MYOG). Moreover, use of a coumarin derivative (CD) revealed a significant reduction in cellular thyroxine, thereby indicating that TTR play a role in the transport of thyroxine. Taken together, these findings suggest that TTR mediated transport of thyroxine represents a survival mechanism necessary for the myogenic program. The results of this study will be highly useful to the strategic development of novel therapeutics to combat muscular dystrophies.
Assuntos
Desenvolvimento Muscular , Mioblastos/citologia , Pré-Albumina/metabolismo , Animais , Ligação Competitiva/efeitos dos fármacos , Diferenciação Celular/efeitos dos fármacos , Linhagem Celular , Movimento Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Cumarínicos/farmacologia , Meios de Cultura Livres de Soro/farmacologia , Técnicas de Silenciamento de Genes , Masculino , Camundongos Endogâmicos C57BL , Desenvolvimento Muscular/efeitos dos fármacos , Músculos/efeitos dos fármacos , Músculos/lesões , Músculos/metabolismo , Mioblastos/efeitos dos fármacos , Mioblastos/metabolismo , Tiroxina/metabolismo , Tri-Iodotironina/metabolismoRESUMO
This study examined the effect of delphinidin on high glucose-induced cell proliferation and collagen synthesis in mesangial cells. Glucose dose-dependently (5.6-25 mM) increased cell proliferation and collagen I and IV mRNA levels, whereas pretreatment with delphinidin (50 µM) prevented cell proliferation and the increased collagen mRNA levels induced by high glucose (25 mM). High glucose increased reactive oxygen species (ROS) generation, and this was suppressed by pretreating delphinidin or the antioxidant N-acetyl cysteine. NADPH oxidase (NOX) 1 was upregulated by high glucose, but pretreatment with delphinidin abrogated this upregulation. Increased mitochondrial superoxide by 25 mM glucose was also suppressed by delphinidin. The NOX inhibitor apocynin and mitochondria-targeted antioxidant Mito TEMPO inhibited ROS generation and cell proliferation induced by high glucose. Phosphorylation of extracellular signal regulated kinase (ERK)1/2 was increased by high glucose, which was suppressed by delphinidin, apocynin or Mito TEMPO. Furthermore, PD98059 (an ERK1/2 inhibitor) prevented the high glucose-induced cell proliferation and increased collagen mRNA levels. Transforming growth factor (TGF)-ß protein levels were elevated by high glucose, and pretreatment with delphinidin or PD98059 prevented this augmentation. These results suggest that delphinidin prevents high glucose-induced cell proliferation and collagen synthesis by inhibition of NOX-1 and mitochondrial superoxide in mesangial cells.
Assuntos
Antocianinas/farmacologia , Proliferação de Células/efeitos dos fármacos , Colágeno/biossíntese , Glucose/farmacologia , Células Mesangiais/metabolismo , Mitocôndrias/metabolismo , NADH NADPH Oxirredutases/metabolismo , Superóxidos/antagonistas & inibidores , Animais , Células Cultivadas , Relação Dose-Resposta a Droga , Glucose/antagonistas & inibidores , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Células Mesangiais/citologia , Camundongos , NADH NADPH Oxirredutases/antagonistas & inibidores , NADPH Oxidase 1 , Espécies Reativas de Oxigênio/metabolismo , Regulação para Cima/efeitos dos fármacosRESUMO
Inhibition of CD36, a fatty acid transporter, has been reported to prevent glucotoxicity and ameliorate high glucose induced beta cell dysfunction. Ezetimibe is a selective cholesterol absorption inhibitor that blocks Niemann Pick C1-like 1 protein, but may exert its effect through suppression of CD36. We attempted to clarify the beneficial effect of ezetimibe on insulin secreting cells and to determine whether this effect is related to change of CD36 expression. mRNA expression of insulin and CD36, intracellular peroxide level and glucose stimulated insulin secretion (GSIS) under normal (5.6 mM) or high glucose (30 mM) condition in INS-1 cells and primary rat islet cells were compared. Changes of the aforementioned factors with treatment with ezetimibe (20 µM) under normal or high glucose condition were also assessed. mRNA expression of insulin was decreased with high glucose, which was reversed by ezetimibe in both INS-1 cells and primary rat islets. CD36 mRNA expression was increased with high glucose, but decreased by ezetimibe in INS-1 cells and primary rat islets. Three-day treatment with high glucose resulted in an increase in intracellular peroxide level; however, it was decreased by treatment with ezetimibe. Decrease in GSIS by three-day treatment with high glucose was reversed by ezetimibe. Palmitate uptake following exposure to high glucose conditions for three days was significantly elevated, which was reversed by ezetimibe in INS-1 cells. Ezetimibe may prevent glucotoxicity in pancreatic ß-cells through a decrease in fatty acid influx via inhibition of CD36.
Assuntos
Anticolesterolemiantes/farmacologia , Antígenos CD36/metabolismo , Ezetimiba/farmacologia , Células Secretoras de Insulina/efeitos dos fármacos , Animais , Antígenos CD36/antagonistas & inibidores , Antígenos CD36/genética , Células Cultivadas , Citometria de Fluxo , Glucose/toxicidade , Insulina/genética , Insulina/metabolismo , Secreção de Insulina , Células Secretoras de Insulina/citologia , Células Secretoras de Insulina/metabolismo , Masculino , Ácido Palmítico/metabolismo , RNA Mensageiro/metabolismo , Ratos , Ratos Sprague-Dawley , Espécies Reativas de Oxigênio/metabolismo , Reação em Cadeia da Polimerase em Tempo RealRESUMO
Oxidative stress and inflammation are associated with skeletal muscle atrophy. Because the activation of toll-like receptor (TLR) 2 induces oxidative stress and inflammation, TLR2 may be directly linked to skeletal muscle atrophy. This study examined the role of TLR2 in skeletal muscle atrophy in wild-type (WT) and TLR2 knockout (KO) mice. Immobilization for 2 weeks increased the expression of cytokine genes and the levels of carbonylated proteins and nitrotyrosine in the skeletal muscle, but these increases were lower in the TLR2 KO mice. Muscle weight loss and a reduction in treadmill running times induced by immobilization were also attenuated in TLR2 KO mice. Furthermore, immobilization increased the protein levels of forkhead box O 1/3, atrogin-1 and muscle ring finger 1 in the WT mice, which was attenuated in TLR2 KO mice. In addition, immobilization-associated increases in ubiquitinated protein levels were lower in the TLR2 KO mice. Immobilization increased the phosphorylation of Akt and p70S6K similarly in WT and KO mice. Furthermore, cardiotoxin injection into the skeletal muscle increased the protein levels of atrogin-1, interleukin-6, and nitrotyrosine and increased the levels of ubiquitinated proteins, although these levels were increased to a lesser extent in TLR2 KO mice. These results suggest that TLR2 is involved in skeletal muscle atrophy, and the inhibition of TLR2 offers a potential target for preventing skeletal muscle atrophy.
Assuntos
Músculo Esquelético/metabolismo , Atrofia Muscular/metabolismo , Receptor 2 Toll-Like/deficiência , Animais , Proteínas Cardiotóxicas de Elapídeos/toxicidade , Citocinas/genética , Modelos Animais de Doenças , Imobilização , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Músculo Esquelético/efeitos dos fármacos , Músculo Esquelético/patologia , Atrofia Muscular/genética , Atrofia Muscular/patologia , Estresse Oxidativo , Fosforilação , Carbonilação Proteica , Proteólise , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Receptor 2 Toll-Like/genética , UbiquitinaçãoRESUMO
The purpose of this study was to investigate the age-related NADPH oxidase (arNOX) activity in patients with age-related knee osteoarthritis (OA). Serum and cartilage arNOX activities were determined using an oxidized ferricytochrome C reduction assay. Full-thickness knee joint cartilages obtained through total knee replacement surgery were graded according to the Outerbridge (OB) classification. Radiographic severity of OA was determined on Knee X-rays according to the Kellgren-Lawrence (K/L) grading system. Cartilage ß-galactosidase, HIF-1α, and GLUT-1 expression levels were evaluated as markers for tissue senescence, hypoxia, and glycolysis. Higher arNOX activities occurred with higher levels of cartilage ß-galactosidase, HIF-1α, and GLUT-1 (P = 0.002). arNOX activity in cartilages with surface defects (OB grade II, III) was higher than in those without the defects (OB grade 0, I) (P = 0.012). Cartilage arNOX activity showed a positive correlation with serum arNOX activity (r = -0.577, P = 0.023). Serum arNOX activity was significantly higher in the OA subgroup with bilateral ROA than in the OA with no or unilateral ROA (2.449 ± 0.81, 2.022 ± 0.251 nM/mL, respectively, P = 0.019). The results of this study demonstrate that OA itself is not a cause to increase arNOX activities, however, arNOX hyperactivity is related to a high degree of cartilage degradation, and a high grade and extent of ROA in age-related OA.
Assuntos
Doenças das Cartilagens/enzimologia , Cartilagem Articular/enzimologia , Osteoartrite do Joelho/diagnóstico , Osteoartrite do Joelho/enzimologia , Osteoporose/diagnóstico , Osteoporose/enzimologia , Biomarcadores/metabolismo , Ativação Enzimática , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , NADH NADPH Oxirredutases , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Estatística como AssuntoRESUMO
The present study examined whether hemin could prevent the development of high-fat diet-induced insulin resistance in the liver and skeletal muscle using a hyperinsulinemic-euglycemic clamp. A four-week high-fat feeding to mice increased the body weight, fat mass, and plasma levels of insulin and lipid, which were reduced by hemin. High-fat diet reduced whole body glucose uptake, which were increased by hemin. Insulin-stimulated hepatic glucose production (HGP) was increased by high-fat diet, but hemin had no significant effect on HGP. Skeletal muscle glucose uptake was reduced by high-fat diet, and hemin normalized the glucose uptake. High-fat diet increased triglyceride levels and mRNA levels of lipogenic enzymes, and decreased mRNA levels of enzymes involved in lipid ß-oxidation, which was reversed by hemin. Phosphorylated AMP-activated protein kinase levels were increased in the skeletal muscle of high fat-fed hemin-injected mice. High-fat diet reduced mRNA levels of antioxidant enzymes and increased mRNA levels of inflammatory cytokines and nitrotyrosine levels, which was normalized by hemin in the skeletal muscle. However, hemin had no significant effect on these factors in the liver. These results suggest that hemin prevents the development of high-fat diet-induced insulin resistance by increased insulin sensitivity in the skeletal muscle.
Assuntos
Dieta Hiperlipídica/efeitos adversos , Hemina/administração & dosagem , Hemina/farmacologia , Resistência à Insulina , Fígado/metabolismo , Músculo Esquelético/metabolismo , Proteínas Quinases Ativadas por AMP/metabolismo , Tecido Adiposo/metabolismo , Animais , Peso Corporal/efeitos dos fármacos , Citocinas/genética , Citocinas/metabolismo , Depressão Química , Expressão Gênica/efeitos dos fármacos , Glucose/metabolismo , Técnica Clamp de Glucose , Glutationa Peroxidase/genética , Glutationa Peroxidase/metabolismo , Heme Oxigenase (Desciclizante)/genética , Heme Oxigenase (Desciclizante)/metabolismo , Hiperinsulinismo/etiologia , Hiperinsulinismo/prevenção & controle , Hiperlipidemias/prevenção & controle , Fígado/enzimologia , Masculino , Camundongos Endogâmicos C57BL , Superóxido Dismutase/genética , Superóxido Dismutase/metabolismo , Triglicerídeos/metabolismo , Tirosina/análogos & derivados , Tirosina/metabolismo , Glutationa Peroxidase GPX1RESUMO
Pseudomonas aeruginosa is a major opportunistic human pathogen. PA2196 from P. aeruginosa is a member of TetR family of transcriptional repressors, which is involved in adaptation to environmental changes as well as bacterial antibiotic resistance. PA2196 consists of nine α-helical bundles divided into two separate domains. The N-terminal domain, called the DNA-binding domain, is composed of helices α1-α3 and has a helix-turn-helix motif. The C-terminal domain, called the ligand-binding domain, has a hydrophobic pocket for ligand binding. Here, PA2196 was shown to bind to a 25 bp semi-palindromic dsDNA located in the upstream region of its own gene. The crystal structure of the PA2196-25mer dsDNA complex determined at a resolution of 2.9 Å revealed that two dimers of PA2196 bound to one dsDNA, with each monomer interacting with the major groove of DNA. Especially, residues in helix α3, including Lys41, Gly42, Ser43, and Tyr45, interacted mainly with the base and phosphate backbone of dsDNA. PA2196 underwent large conformational changes upon DNA binding, as the distances between DNA-binding domains measured between two G42s in subunits A and B decreased from 41.7 Å to 36.8 Å. Our crystal structure of PA2196-25mer dsDNA complex revealed that PA2196 is similar to QacR in that two dimers bound to one dsDNA through specific interactions.
Assuntos
Proteínas de Bactérias/química , DNA Bacteriano/química , Proteínas Repressoras/química , Sequência de Aminoácidos , Cristalografia por Raios X , Modelos Moleculares , Dados de Sequência Molecular , Ligação Proteica , Conformação Proteica , Pseudomonas aeruginosa/química , Alinhamento de SequênciaRESUMO
The biologic actions of insulin-like growth factor-1(IGF-1) are associated with cell growth, differentiation, migration, and survival. IGF-1 constitutes the pathogenic factor in formation of nasal polyps and the regulatory factor in expression of mucins. However, the effect of IGF-1 on MUC8 and MUC5B expression has not been reported. Therefore, in this study, the effect and brief signaling pathway of IGF-1 on MUC8 and MUC5B expression were investigated in human airway epithelial cells. In mucin-producing human NCI-H292 airway epithelial cells and the primary cultures of normal human nasal epithelial cells, the effect and signaling pathway of IGF-1 on MUC8 and MUC5B expression were investigated using reverse transcriptase-polymerase chain reaction (RT-PCR), real-time PCR, enzyme immunoassay, and immunoblot analysis with specific inhibitors and small interfering RNA (siRNA) for mitogen-activated protein kinase (MAPK). IGF-1 induced MUC8 and MUC5B expression, and activated phosphorylation of ERK1/2 and p38 MAPK. U0126 (ERK1/2 inhibitor) and SB203580 (p38 MAPK inhibitor) inhibited IGF-1 induced MUC8 and MUC5B mRNA expression. In addition, the knockdown of ERK1 and p38 MAPK by siRNA significantly blocked IGF-1 induced MUC8 and MUC5B mRNA expression; the knockdown of ERK2 MAPK by siRNA did not. These results demonstrate for the first time that IGF-1 induced MUC8 and MUC5B expression is regulated by activation of the ERK1 and p38 MAPK signaling pathway in human airway epithelial cells.
Assuntos
Fator de Crescimento Insulin-Like I/fisiologia , Proteína Quinase 3 Ativada por Mitógeno/metabolismo , Mucina-5B/biossíntese , Mucinas/biossíntese , Mucosa Respiratória/metabolismo , Proteínas Quinases p38 Ativadas por Mitógeno/metabolismo , Linhagem Celular , Humanos , Imidazóis/farmacologia , Fator de Crescimento Insulin-Like I/farmacologia , Proteína Quinase 3 Ativada por Mitógeno/antagonistas & inibidores , Fosforilação , Piridinas/farmacologia , Mucosa Respiratória/efeitos dos fármacos , Proteínas Quinases p38 Ativadas por Mitógeno/antagonistas & inibidoresRESUMO
Females are more often affected by constipation than males, especially during pregnancy, which is related to the menstrual cycle. Although still controversial, alterations of progesterone and estrogen may be responsible. Therefore, this study was conducted in order to determine whether the female sex steroid hormone itself is responsible for development of constipation in both female and male mice. Administration of estrogen resulted in a decrease in weight of accumulated feces on days 2, 3, 4, and 5 in male mice and on day 5 in female mice, compared with the control group, but progesterone administration did not. Administration of estrogen resulted in a decrease in gastrointestinal movement, compared to normal; however, no significant change was observed by administration of progesterone. In conclusion, estrogen, rather than progesterone, may be a detrimental factor of constipation via decreased bowel movement in mice.
RESUMO
Caloric restriction is a popular approach to treat obesity and its associated chronic illnesses but is difficult to maintain for a long time. Intermittent fasting is an alternative and easily applicable dietary intervention for caloric restriction. Moreover, intermittent fasting has beneficial effects equivalent to those of caloric restriction in terms of body weight control, improvements in glucose homeostasis and lipid profiles, and anti-inflammatory effects. In this review, the beneficial effects of intermittent fasting are discussed.
RESUMO
High-velocity actions are central to clinical and athletic performance, with jumping used to assess outcomes in sports medicine. Ground reaction force (GRF)-based methods are the standard for computing jump characteristics, but require mass estimation and GRF integration, potentially resulting in mass errors which influence outcomes. This study investigated how simulated mass errors influenced the centre of mass (CoM) trajectory during a countermovement jump. The mass was estimated from the static GRF, and simulated errors were added or subtracted to the mass. The CoM trajectory with simulated mass errors was computed using the GRF-based method to investigate mass mis-estimation's influence on jump height. A regression model indicated that, for a 1 kg mass change, there was a 7.7 cm jump height change, and the jump height differed by 11.5 ± 0.4 cm from the maximum to minimum error. A 2-way ANOVA identified significant height differences between the starting position, and landing, or final position with mass errors of ± 0.2 or ± 0.4 kg. These results reveal that small mass errors may produce inaccurate conclusions regarding performance changes, and that errors may propagate throughout the jump trajectory. Caution may be necessary when using GRF-based methods to compute jump height as a power proxy.
RESUMO
Understanding the diversity of soil organisms is complicated by both scale and substrate. Every footprint we leave in the soil covers hundreds to millions of organisms yet we cannot see them without extremely laborious extraction and microsopy endeavors. Studying them is also challenging. Keeping them alive so that we can understand their lifecycles and ecological roles ranges from difficult to impossible. Functional and taxonomic identification of soil organisms, while possible, is also challenging. Here we present the Smart Soil Organism Detector, an instrument and machine learning pipeline that combines high-resolution imaging, multi-spectral sensing, large-bore flow cytometry, and machine learning to extract, isolate, count, identify, and separate soil organisms in a high-throughput, high-resolution, non-destructive, and reproducible manner. This system is not only capable of separating alive nematodes, dead nematodes, and nematode cuticles from soil with 100% out-of-sample accuracy, but also capable of identifying nematode strains (sub-species) with 95.5% out-of-sample accuracy and 99.4% specificity. Soil micro-arthropods were identified to class with 96.1% out-of-sample accuracy. Broadly applicable across soil taxa, the Smart SOD system is a tool for understanding global soil biodiversity.
Assuntos
Técnicas Biossensoriais , Nematoides , Animais , Solo , Biodiversidade , Aprendizado de MáquinaRESUMO
AIMS: Prolonged high levels of cytokines, glucose, or free fatty acids are associated with diabetes, elevation of cytosolic Ca2+ concentration ([Ca2+]C), and depletion of Ca2+ concentration in the endoplasmic reticulum (ER) of pancreatic beta cells. This Ca2+ imbalance induces ER stress and apoptosis. Lupenone, a lupan-type triterpenoid, is beneficial in diabetes; however, its mechanism of action is yet to be clarified. This study evaluated the protective mechanism of lupenone against thapsigargin-induced ER stress and apoptosis in pancreatic beta cells. MATERIALS AND METHODS: MIN6, INS-1, and native mouse islet cells were used. Western blot for protein expressions, measurement of [Ca2+]C, and in vivo glucose tolerance test were mainly performed. KEY FINDINGS: Thapsigargin increased the protein levels of cleaved caspase 3, cleaved PARP, and the phosphorylated form of JNK, ATF4, and CHOP. Thapsigargin increased the interaction between stromal interaction molecule1 (Stim1) and Orai1, enhancing store-operated calcium entry (SOCE). SOCE is further activated by protein tyrosine kinase 2 (Pyk2), which is Ca2+-dependent and phosphorylates the tyrosine residue at Y361 in Stim1. Lupenone inhibited thapsigargin-mediated Pyk2 activation, suppressed [Ca2+]C, ER stress, and apoptosis. Lupenone restored impaired glucose-stimulated insulin secretion effectuated by thapsigargin and glucose intolerance in a low-dose streptozotocin-induced diabetic mouse model. SIGNIFICANCE: These results suggested that lupenone attenuated thapsigargin-induced ER stress and apoptosis by inhibiting SOCE; this may be due to the hindrance of Pyk2-mediated Stim1 tyrosine phosphorylation. In beta cells that are inevitably exposed to frequent [Ca2+]C elevation, the attenuation of abnormally high SOCE would be beneficial for their survival.
Assuntos
Diabetes Mellitus , Células Secretoras de Insulina , Lupanos , Triterpenos , Animais , Camundongos , Apoptose , Cálcio/metabolismo , Linhagem Celular , Diabetes Mellitus/metabolismo , Estresse do Retículo Endoplasmático , Quinase 1 de Adesão Focal/metabolismo , Quinase 2 de Adesão Focal/metabolismo , Glucose/metabolismo , Células Secretoras de Insulina/metabolismo , Fosforilação , Tapsigargina/efeitos adversos , Triterpenos/metabolismo , Tirosina/metabolismo , Lupanos/farmacologiaRESUMO
The purpose of the present study was to determine whether exposure of pancreatic islets to glucotoxic conditions changes fatty acid translocase cluster determinant 36 (CD36) and examine the role of CD36 on the induction of glucotoxicity. We measured the changes of CD36 and insulin secretion in high glucose (30 mM) exposed INS-1 cells and CD36 suppressed INS-1 cells by transfection of CD36 siRNA. The intracellular peroxide level of INS-1 cells increased in the high glucose media compared to normal glucose (5.6mM) media. The mRNA levels of insulin and PDX-1, as well as glucose stimulated insulin secretion (GSIS) were decreased in INS-1 cells exposed to high glucose media compared to normal glucose media, while CD36 and palmitate uptake were significantly elevated with exposure to high glucose media for 12h. The inhibition of CD36 reversed the decreased GSIS and intracellular peroxide level in INS-1 cells. These results suggest that high glucose may exacerbate glucotoxicity via increasing fatty acid influx by elevation of CD36 expression, and that CD36 may be a possible target molecule for preventing glucotoxicity in pancreatic beta-cells.
Assuntos
Antígenos CD36/metabolismo , Glucose/antagonistas & inibidores , Hiperglicemia/enzimologia , Células Secretoras de Insulina/metabolismo , Linhagem Celular Tumoral , Ácidos Graxos/metabolismo , Glucose/metabolismo , Glucose/toxicidade , Humanos , Células Secretoras de Insulina/efeitos dos fármacos , Células Secretoras de Insulina/patologiaRESUMO
OBJECTIVE: To examine if peroxiredoxin 2 (Prx2) deficiency aggravates high-fat diet-induced insulin resistance. MATERIAL AND METHODS: Insulin sensitivity was measured in Prx2 knockout (KO) and wild-type (WT) littermates using the hyperinsulinemic-euglycemic clamp. RESULTS: Whole body glucose turnover, glucose uptake, and levels of glucose transporter 4 (Glut4) protein in the skeletal muscle were found to be lower. This was followed by increased expression of oxidative stress markers in Prx2 KO mice than that in WT mice in the control diet group. Although, a 12-week high-fat diet induced insulin resistance and enhanced oxidative stress in both genotypes, there was no difference between WT and Prx2 KO mice with respect to insulin sensitivity and the level of oxidative stress markers. Accordingly, the levels of phosphorylated Akt and Glut4 were similar between the two genotypes. CONCLUSION: These results suggest that Prx2 does not affect high-fat diet-induced oxidative stress and insulin resistance in mice.