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CTRP6, a newly identified adiponectin analogue, has been shown to be involved in inflammation, diabetes and cardiovascular diseases. Recently, increasing evidence has shown that CTRP6 plays a critical role in fibrotic diseases, such as myocardial fibrosis and skin fibrosis. FAO, an important energy source for kidney proximal tubular cells, also participates in the process of fibrosis. Therefore, our study aimed to investigate the effect of CTRP6 on mediating FAO in kidney fibrosis and the underlying associated mechanism. Firstly, the activity of CTRP6 and the key enzymes of FAO (CPT1A, ACOX1) were tested in vivo and vitro. Next, the regulatory effect of CTRP6/AMPK on FAO was accessed in animal models and in cell lines. Additionally, we explored the effect of exogenous recombinant CTRP6 on renal tubular epithelial cell differentiation. Decreased CTRP6 and p-AMPK were detected in UUO-induced kidney fibrosis and in TGF-ß1-treated HK-2 cells. We also observed that defective FAO occurred during kidney fibrosis. Moreover, the human CTRP6 peptide could inhibit the ECM deposition and promote the phosphorylation of AMPK by promoting FAO. However, the inhibitory effects of CTRP6 on TGF-ß1-induced ECM deposition and the protective effects of CTRP6 on FAO could be abolished by compound C, a selective inhibitor of AMPK. Compound C also reversed the CTRP6-mediated upregulation of p-AMPK. The mediation of FAO by CTRP6 plays a key role in kidney fibrosis by regulating TGF-ß1-induced renal tubular epithelial cell differentiation by promoting FAO, which is mediated via AMPK activation.
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Proteínas Quinasas Activadas por AMP/metabolismo , Adipoquinas/metabolismo , Colágeno/metabolismo , Ácidos Grasos/metabolismo , Enfermedades Renales/enzimología , Túbulos Renales Proximales/enzimología , Acil-CoA Oxidasa/genética , Acil-CoA Oxidasa/metabolismo , Adipoquinas/genética , Animales , Carnitina O-Palmitoiltransferasa/genética , Carnitina O-Palmitoiltransferasa/metabolismo , Línea Celular , Colágeno/genética , Modelos Animales de Enfermedad , Fibrosis , Humanos , Enfermedades Renales/etiología , Enfermedades Renales/genética , Enfermedades Renales/patología , Túbulos Renales Proximales/efectos de los fármacos , Túbulos Renales Proximales/patología , Masculino , Ratones , Oxidación-Reducción , Fosforilación , Transducción de Señal , Factor de Crecimiento Transformador beta1/farmacología , Obstrucción Ureteral/complicacionesRESUMEN
Pancreatic cancer (PC) is one of the top deaths causing cancers with low 5-year survival rate. Long non-coding RNAs (lncRNAs) are recognized as a crucial type of nonprotein-coding transcripts implicated in tumorigenesis. Emerging evidence has implied that LINC00152 exerts the potential oncogenic functions in various cancers. Nevertheless, the role of LINC00152 in PC remains elusive. In the present study, we found that LINC00152 was significantly up-regulated while miR-150 was down-regulated both in tissues and cell lines of PC, indicating their negative correlation in PC progression. Functionally, overexpression of LINC00152 promoted cell proliferation, migration and invasion, while LINC00152 knockdown reversed these effects. Mechanistic experiments reveal that miR-150 acted as a target of LINC00152 confirmed by luciferase reporter assay. Moreover, inhibition of miR-150 could markedly attenuate the suppression of cell proliferation, migration and invasion by knocking down LINC00152. Altogether, our findings concluded that LINC00152 facilitated PC progression through inhibiting miR-150 expression, indicating an innovative therapeutic target for PC.
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ETHNOPHARMACOLOGICAL RELEVANCE: The edible plant Physalis alkekengi (PA) is used in traditional medicine to treat diabetes. However, the anti-diabetic effects and constituents of the fruit and aerial parts of this plant have not been studied extensively. AIM OF THE STUDY: The purpose of this study was to investigate the antidiabetic potential of Physalis alkekengi and identify its chemical constituents. MATERIALS AND METHODS: In the present study, the in vitro glucose uptake capacity was tested using the 2-[N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)amino]-2-deoxy-d-glucose (2-NBDG) assay in HepG2 cells. Secondly, the anti-diabetes effects of the ethyl acetate extracts of the aerial parts/fruit (EAP/EAF) of P. alkekengi were evaluated in high-fat diet-fed and streptozotocin-induced diabetic rats (seven groups, nâ¯=â¯7) daily at doses of 300 and 600â¯mg/kg for 28 days. Fasting blood glucose (FBG) was measured with a glucometer and the levels of total cholesterol (TC), triglyceride (TG), glycated serum protein (GSP), and fasting insulin (FINS) were measured by ELISA. Furthermore, insulin sensitivity index (ISI) and homeostasis model assessment-insulin resistance index (HOMA-IR) were calculated based on FBG and FINS. Changes in blood glucose concentration were assessed after an oral glucose challenge in diabetic rats treated with EAF and EAP extracts. In all assays, rosiglitazone, a current antidiabetic drug and insulin sensitizer, was also tested. Finally, the compounds in EAP were identified by HPLC-ESI-QTOF-MS analysis. RESULTS: EAP increased the uptake of 2-NBDG, a measure of direct glucose uptake, in HepG2 cells. Next, in diabetic rats treated with P. alkegenki extracts for 28 days, the levels of FBG, TC, TG and GSP and were lowered effectively, while FINS was increased significantly. EAP/EAF enhanced insulin sensitivity significantly as measured by ISI and HOMA-IR along with oral glucose tolerance test analysis. The EAP generally exerted the greatest effects. Lastly, a HPLC-ESI-Q-TOF-MS analysis identified 50 compounds, including 26 physalins, 10 flavonoids, and 9 phenolic acids, with 21 compounds found for the first time in P. alkekengi. CONCLUSIONS: The results support the merit of P. alkekengi as an antidiabetic herbal medicine or dietary supplement.
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Hipoglucemiantes/uso terapéutico , Physalis , Extractos Vegetales/uso terapéutico , Acetatos/química , Animales , Cromatografía Líquida de Alta Presión , Diabetes Mellitus Experimental/sangre , Diabetes Mellitus Experimental/tratamiento farmacológico , Glucosa/metabolismo , Prueba de Tolerancia a la Glucosa , Células Hep G2 , Humanos , Hipoglucemiantes/análisis , Hipoglucemiantes/farmacología , Insulina/sangre , Resistencia a la Insulina , Masculino , Fitoquímicos/análisis , Fitoquímicos/farmacología , Fitoquímicos/uso terapéutico , Fitoterapia , Extractos Vegetales/análisis , Extractos Vegetales/farmacología , Ratas , Ratas Sprague-Dawley , Solventes/química , Espectrometría de Masa por Ionización de ElectrosprayRESUMEN
BACKGROUND: To study the clinical effect of low molecular heparin on unexplained recurrent spontaneous abortion (URSA). METHODS: A total of 120 URSA patients were collected in our hospital from October 2015 to September 2017. They were divided into two groups: control group (n = 60) and observation group (n = 60). The patients in the control group were administered with progesterone and human chorionic gonadotropin, and the observation group with low molecular heparin. Pregnancy outcomes, incidence of complications in pregnancy and adverse drug reactions were compared in the two groups. RESULTS: The pregnancy success rate of patients in the observation group (90.00%) is higher than that in the control group (68.33%) (p < 0.05). The incidence of complications in pregnancy in the observation group (90.00%) is lower than those in the control group (68.33%) (p < 0.05). The incidence of adverse drug reactions between the patients in the observation group (20.00%) and those in the control group (23.33%) showed no significant difference (p > 0.05). CONCLUSIONS: Low molecular heparin treatment can improve pregnancy success rate and reduce the incidence of complications in the URSA patients. Low molecular heparin is characterized by safety and reliability and has potential for application in clinic.
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Aborto Habitual/prevención & control , Aborto Espontáneo/prevención & control , Heparina de Bajo-Peso-Molecular/administración & dosificación , Resultado del Embarazo , Adulto , Gonadotropina Coriónica/administración & dosificación , Femenino , Humanos , Embarazo , Progesterona/administración & dosificación , Resultado del TratamientoRESUMEN
The aims of the present study were to assess the anti-diabetic effects of Physalis alkekengi L. (PA) in 3T3-L1 pre-adipocyte cells and HepG2-GFP-CYP2E1 (E47) cells and in a pre-diabetic rat model, as well as to identify the active chemical constituents. The in vitro results showed that PA has a strong anti-diabetic capacity to relieve oxidative stress and inhibit α-glucosidase activity. Mechanistic analysis also showed that ethyl acetate extracts of aerial parts and fruit of PA (PAG-EA and PAF-EA) enhanced glucose transporter 4 expression and function as well as enhanced insulin sensitivity by inhibiting the expression of cytochrome P450-2E1 (CYP2E1) mRNA and protein. In vivo, PAG-EA and PAF-EA significantly decreased the levels of fasting blood glucose and fasting insulin, as well as total cholesterol and triglyceride, in the pre-diabetic rats. The results from insulin sensitivity index and homeostasis model assessment-insulin resistance index along with an oral glucose tolerance test also showed that PAG-EA and PAF-EA could significantly enhance the insulin sensitivity, which confirmed the in vitro findings. Moreover, HPLC-ESI-QTOF-MS analysis identified flavonoids, physalins and phenolic acids as the main plant constituents. Our findings support the ethnopharmacological use of PA fruit, along with its aerial parts, as a strong anti-diabetic agent. The EA fraction, especially the constituent polyphenols and flavonoids, may have a good potential to treat diabetes.
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Diabetes Mellitus Experimental/tratamiento farmacológico , Flavonoides/farmacología , Hipoglucemiantes/farmacología , Physalis/química , Polifenoles/farmacología , Células 3T3-L1 , Animales , Antioxidantes/aislamiento & purificación , Antioxidantes/farmacología , Flavonoides/aislamiento & purificación , Frutas/química , Prueba de Tolerancia a la Glucosa , Células Hep G2 , Humanos , Hipoglucemiantes/aislamiento & purificación , Resistencia a la Insulina , Masculino , Ratones , Estrés Oxidativo , Componentes Aéreos de las Plantas/química , Polifenoles/aislamiento & purificación , Ratas , Ratas Sprague-DawleyRESUMEN
ß3-adrenoceptor (ß3-AR) has been shown to promote myocardial apoptosis. However, the exact physiological role and importance of this receptor in the human myocardium, and its underlying mode of action, have not been fully elucidated. The present study aimed to determine the effects of ß3-AR on the promotion of myocardial apoptosis and on norepinephrine (NE) injury. We analyzed NE-induced cardiomyocyte (CM) apoptosis by using a TUNEL and an annexin V/propidium iodide apoptosis assay. Furthermore, we investigated the NE-induced expression of the apoptosis marker genes Akt and p38MAPK, their phosphorylated counterparts p-Akt and p-p38MAPK, caspase-3, Bcl-2, and Bax. In addition, we determined the effect of a 48-h treatment with a ß3-AR agonist and antagonist on expression of these marker genes. ß3-AR overexpression was found to increase CM apoptosis, accompanied by an increased expression of caspase-3, bax/bcl-2, and p-p38MAPK. In contrast, the ß3-blocker reduced apoptosis of CMs and the associated elevated Akt expression. We identified a novel and potent anti-apoptosis mechanism via the PI3K/Akt pathway and a pro-apoptosis pathway mediated by p38MAPK.
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Apoptosis , Miocitos Cardíacos/metabolismo , Fosfatidilinositol 3-Quinasas/metabolismo , Proteínas Proto-Oncogénicas c-akt/metabolismo , Receptores Adrenérgicos beta 3/metabolismo , Proteínas Quinasas p38 Activadas por Mitógenos/metabolismo , Agonistas Adrenérgicos/farmacología , Antagonistas Adrenérgicos/farmacología , Animales , Células Cultivadas , Miocitos Cardíacos/efectos de los fármacos , Ratas , Ratas Sprague-Dawley , Receptores Adrenérgicos beta 3/genética , Transducción de SeñalRESUMEN
INTRODUCTION: Triple-negative breast cancer (TNBC) patients often face a high risk of early relapse characterized by extensive metastasis. Previous works have shown that aberrant cell surface glycosylation is associated with cancer metastasis, suggesting that altered glycosylations might serve as diagnostic signatures of metastatic potential. To address this question, we took TNBC as an example and analyzed six TNBC cell lines, derived from a common progenitor, that differ in metastatic potential. METHODS: We used a microarray with 91 lectins to screen for altered lectin bindings to the six TNBC cell lines. Candidate lectins were then verified by lectin-based flow cytometry and immunofluorescent staining assays using both TNBC/non-TNBC cancer cells. Patient-derived tissue microarrays were then employed to analyze whether the staining of Ricinus communis agglutinin I (RCA-I), correlated with TNBC severity. We also carried out real-time cell motility assays in the presence of RCA-I. Finally, liquid chromatography-mass spectrometry/tandem spectrometry (LC-MS/MS) was employed to identify the membrane glycoproteins recognized by RCA-I. RESULTS: Using the lectin microarray, we found that the bindings of RCA-I to TNBC cells are proportional to their metastatic capacity. Tissue microarray experiments showed that the intensity of RCA-I staining is positively correlated with the TNM grades. The real-time cell motility assays clearly demonstrated RCA-I inhibition of adhesion, migration, and invasion of TNBC cells of high metastatic capacity. Additionally, a membrane glycoprotein, POTE ankyrin domain family member F (POTEF), with different galactosylation extents in high/low metastatic TNBC cells was identified by LC-MS/MS as a binder of RCA-I. CONCLUSIONS: We discovered RCA-I, which bound to TNBC cells to a degree that is proportional to their metastatic capacities, and found that this binding inhibits the cell invasion, migration, and adhesion, and identified a membrane protein, POTEF, which may play a key role in mediating these effects. These results thus indicate that RCA-I-specific cell surface glycoproteins may play a critical role in TNBC metastasis and that the extent of RCA-I cell binding could be used in diagnosis to predict the likelihood of developing metastases in TNBC patients.
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Membrana Celular/metabolismo , Lectinas de Plantas/metabolismo , Polisacáridos/metabolismo , Neoplasias de la Mama Triple Negativas/metabolismo , Neoplasias de la Mama Triple Negativas/patología , Proteínas Portadoras/metabolismo , Línea Celular Tumoral , Movimiento Celular , Femenino , Humanos , Glicoproteínas de Membrana/metabolismo , Metástasis de la Neoplasia , Unión Proteica , Mapeo de Interacción de Proteínas , Reproducibilidad de los Resultados , Espectrometría de Masas en TándemAsunto(s)
Reserva del Flujo Fraccional Miocárdico/fisiología , Imagen por Resonancia Magnética/normas , Imagen de Perfusión Miocárdica/normas , Tomografía Computarizada de Emisión de Fotón Único/normas , Tomografía Computarizada por Rayos X/normas , Enfermedad de la Arteria Coronaria/diagnóstico por imagen , Enfermedad de la Arteria Coronaria/fisiopatología , HumanosRESUMEN
To investigate the local micro-/nanoscale region in a large scale sample, an image reconstruction method for nanometer computed tomography (nano-CT) was proposed in this paper. In the algorithm, wavelets were used to localize the filtered-backprojection (FBP) algorithm because of its space-frequency localization property. After the implementation of the algorithm, two simulation local reconstruction experiments were performed to confirm its effectiveness. Three evaluation criteria were used in the experiments to judge the quality of the reconstructed images. The experimental results showed that the algorithm proposed in this paper performed best because (1) the quality of its results had improved 20%-30% compared to the results of FBP and 10%-30% compared to the results of another wavelet algorithm; (2) the new algorithm was stable under different circumstances. Besides, an actual reconstruction experiment was performed using real projection data that had been collected in a CT experiment. Two-dimensional (2D) and three-dimensional (3D) images of the sample were reconstructed. The microstructure of the sample could be clearly observed in the reconstructed images. Since much attention has been directed towards the nano-CT technique to investigate the microstructure of materials, this new wavelet-based local tomography algorithm could be considered as a meaningful effort.
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Algoritmos , Diagnóstico por Imagen/métodos , Procesamiento de Imagen Asistido por Computador/métodos , Imagenología Tridimensional , Tomografía Computarizada por Rayos XRESUMEN
In order to study the influence on the mechanical properties caused by microstructure evolution of metal powder in extreme environment, 3D real-time observation of the microstructure evolution of Al-Ti mixed powder in high temperature and microwave compound fields was realized by using synchrotron radiation computerized topography (SR-CT) technique; the spatial resolution was enhanced to 0.37 µm/pixel through the designed equipment and the introduction of excellent reconstruction method for the first time. The process of microstructure evolution during sintering was clearly distinguished from 2D and 3D reconstructed images. Typical sintering parameters such as sintering neck size, porosity, and particle size of the sample were presented for quantitative analysis of the influence on the mechanical properties and the sintering kinetics during microwave sintering. The neck size-time curve was obtained and the neck growth exponent was 7.3, which indicated that surface diffusion was the main diffusion mechanism; the reason was the eddy current loss induced by the external microwave fields providing an additional driving force for mass diffusion on the particle surface. From the reconstructed images and the curve of porosity and average particle size versus temperature, it was believed that the presence of liquid phase aluminum accelerated the densification and particle growth.
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Microondas , Aluminio/química , Cinética , TemperaturaRESUMEN
Microsomal transfer protein (MTP), a lipid transfer protein localized in the endoplasmic reticulum of hepatocytes and enterocytes, plays an important role in the development of nonalcoholic fatty liver disease (NAFLD). Many existing studies have demonstrated that a common polymorphism (-493G>T, rs1800591 G>T) in the MTP gene may be implicated in the development and progression of NAFLD, but individually published results are inconclusive. This meta-analysis aimed to investigate whether MTP -493G>T polymorphism may be a potential risk factor for NAFLD. We searched CISCOM, CINAHL, Web of Science, PubMed, Google Scholar, EBSCO, Cochrane Library, and CBM databases from inception through October 1, 2013. Meta-analysis was performed using the STATA 12.0 software. Eleven clinical case-control studies with a total of 636 NAFLD cases and 918 healthy controls met the inclusion criteria. Our meta-analysis results revealed that MTP -493G>T polymorphism was strongly correlated with an increased risk of NAFLD. Subgroup analysis by ethnicity suggested that MTP -493G>T polymorphism might increase individuals' susceptibility to NAFLD among both Caucasian and non-Caucasian populations. No publication bias was observed in this meta-analysis. In short, the present meta-analysis indicates that MTP -493G>T polymorphisms may contribute to individuals' susceptibility to NAFLD. Thus, MTP -493G>T polymorphism may be a valuable and practical biomarker for early detection of NAFLD.
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Proteínas Portadoras/genética , Hígado Graso/genética , Sustitución de Aminoácidos , Estudios de Casos y Controles , Niño , Predisposición Genética a la Enfermedad , Humanos , Persona de Mediana Edad , Enfermedad del Hígado Graso no Alcohólico , Polimorfismo GenéticoRESUMEN
PURPOSE: The aim of this study was to investigate effects of adipose-derived mesenchymal stem cells (AMSCs) on radioresistance of breast cancer cells. MATERIALS AND METHODS: MTT assays were used to detect any influence of AMSC supernatants on proliferation of breast cancer cells; cell migration assays were used to determine the effect of breast cancer cells on the recruitment of AMSCs; the cell survival fraction post-irradiation was assessed by clonogenic survival assay; γ-H2AX foci number post-irradiation was determined via fluorescence microscopy; and expression of IGF-1R was detected by Western blotting. RESULTS: AMSC supernatants promoted proliferation and radioresistance of breast cancer cells. Breast cancer cells could recruit AMSCs, especially after irradiation. IGF-1 derived from AMSCs might be responsible for the radioresistance of breast cancer cells. CONCLUSIONS: Our results suggest that AMSCs in the tumor microenvironment may affect the outcome of radiotherapy for breast cancer in vitro.
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Neoplasias de la Mama/metabolismo , Proliferación Celular/fisiología , Factor I del Crecimiento Similar a la Insulina/metabolismo , Células Madre Mesenquimatosas/metabolismo , Radiación , Tejido Adiposo/citología , Neoplasias de la Mama/radioterapia , Línea Celular Tumoral , Movimiento Celular/efectos de la radiación , Proliferación Celular/efectos de la radiación , Femenino , Histonas/metabolismo , Histonas/efectos de la radiación , Humanos , Células MCF-7 , Células Madre Mesenquimatosas/citología , Receptor IGF Tipo 1 , Receptores de Somatomedina/metabolismo , Receptores de Somatomedina/efectos de la radiación , Microambiente TumoralRESUMEN
In our previous study, significantly high expression levels of matrix-remodeling associated 5 (MXRA5) were identified in fresh-cultured colorectal cancer (CRC) tissues compared with their normal adjacent mucosa by differential secretome analysis. Whether MXRA5 is a potential serum biomarker of CRC has not been evaluated. The aim of this study was to investigate the association between MXRA5 expression and clinicopathological characteristics of CRC patients. The MXRA5 expression levels were determined by quantitative real-time PCR (qRT-PCR) and immunohistochemistry (IHC) in 20 colorectal adenoma tissues, 156 CRC tissues and their corresponding adjacent normal mucosa. Relative quantity (RQ) value and immunoreactive score (IRS) were used for quantitative assessment. The staining for MXRA5 protein was mainly located in the cytoplasm of CRC cells. All CRC tissues were positively stained, with a higher expression rate (IRS>4) of 67% (105/156), and a lower expression rate (IRS≤4) of 33% (51/156). Meanwhile, their corresponding normal tissues exhibited little positive staining; the higher expression rate was 0% (0/156) and the lower expression rate was 25% (16/156). Additionally, more than half of the adenoma tissues were positively stained; the higher expression rate was 15% (3/20) and the lower expression rate was 50% (10/20). The MXRA5 protein positive staining rates were significantly correlated with the lesion sites (colon vs. rectum, 76 vs. 59%), TNM staging (I+II vs. III+IV, 56 vs. 73%) and metastasis (present vs. absent; 76 vs. 61%) with the most high positive staining rate observable in omental metastasis (82%). However, MXRA5 mRNA expression levels showed no significant differences between CRC tissues and their corresponding normal tissues, and no significant correlation between IRS and corresponding RQ value was observed. In this study, we present the first evaluation of MXRA5 protein expression in CRC tissue. Our results revealed that MXRA5 protein is aberrantly expressed in CRC tissues, and has potential value in early detection of CRC and prediction of omental metastasis.
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Lipopolysaccharide (LPS) from gram negative bacteria plays an important role in the pathophysiology of neurodegenerative diseases. Many evidences showed that LPS-induced neuroinflammation is related to upregulation of NF-kappaB. Here, we report that long-term treatment of lower dosage LPS mainly causes upregulation of Id2 protein. As an inhibitor of cell differentiation, Id2 plays an import role in adult olfactory neurogenesis. However, Id2 protein in brain acts as two edges in a sword, persist over-expression of Id2 in brain can induce neurodamages and may be related to neurodegeneration.
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Encéfalo/efectos de los fármacos , Encéfalo/metabolismo , Proteína 2 Inhibidora de la Diferenciación/metabolismo , Lipopolisacáridos/administración & dosificación , Lipopolisacáridos/farmacología , Animales , Bencimidazoles/metabolismo , Western Blotting , Encéfalo/patología , Muerte Celular/efectos de los fármacos , Regulación de la Expresión Génica/efectos de los fármacos , Proteína 2 Inhibidora de la Diferenciación/genética , Inyecciones Intraperitoneales , Ratones , Ratones Endogámicos C57BL , Propidio/metabolismo , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Factores de TiempoRESUMEN
Ca2+ spark is the elementary Ca2+ signaling event in muscle excitation-contraction coupling. The rise time of Ca2+ spark is rather stable under different conditions, suggesting consistent open duration of ryanodine receptors (RyRs) in vivo. It has been proposed that the array-based behavior of RyRs plays an important role in shaping Ca2+ spark dynamics, particularly in controlling the open duration of RyR clusters. Therefore, we investigated the possible role of inter-RyR coupling in stabilization of the open time of arrayed RyRs under several potential perturbations, for instance, array size, inter-RyR coupling noise, and up-regulation or down-regulation of the activity of partial RyRs in the array. We found that RyR arrays with dynamic coupling showed consistent open duration against the perturbations, whereas the RyR array with constant coupling did not. On the other hand, the open probability and amplitude of RyR arrays with dynamic interreceptor coupling were sensitive to the perturbations. These two points were consistent with experimental observations, indicating that the RyR array with dynamic coupling could recapitulate in vivo open properties of RyRs. Our findings support the idea that dynamic coupling is a feasible in vivo working mechanism of RyR arrays.
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Canal Liberador de Calcio Receptor de Rianodina/metabolismo , Animales , Simulación por Computador , Miocitos Cardíacos/metabolismo , Probabilidad , Unión Proteica , Ratas , TemperaturaRESUMEN
Ryanodine receptors (RyRs) usually form two-dimensional regular array in sarcoplasmic reticulum membranes in muscle cells. The inter-RyRs coupling may be essential for the maintenance of quiescent Ca2+ release in resting state, as well as for the coordinated activation and rapid termination of RyR-mediated Ca2+ release during excitation-contraction coupling. In our previous work, we have reported that the inter-RyRs interaction is modulated by RyR channel's functional state, which inspired us to propose a novel working mechanism of RyR array: "dynamic inter-RyR coupling". In this work, we built a simple model based on cellular automata and the Monte-Carlo method to quantitatively investigate the roles of intermolecular coupling and its modulation in regulating the signaling capabilities of RyR array. Our simulation results showed that with a suitable inter-RyR coupling strength, the combination of rest stability and high response efficiency, namely optimal signal/noise ratio, of Ca2+ signaling could be achieved. Moreover, we also found the continued coupling between open RyRs would delay the system termination rate. The coacquisition of robust termination of array opening relied on the proper decrease of coupling strength between activated RyRs. Obviously, such temporally asymmetric coupling would simultaneously endow the system with physiologically relevant resting stability and fast termination.
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Calcio/fisiología , Modelos Biológicos , Canal Liberador de Calcio Receptor de Rianodina/fisiología , Activación del Canal Iónico , Método de Montecarlo , Conformación Proteica , Retículo Sarcoplasmático/fisiologíaRESUMEN
Receptor proteins in both eukaryotic and prokaryotic cells often form regular lattice or array in the membrane. Recent theoretical analyses indicate that such arrays may provide a novel mechanism for receptor signaling regulation in cells. The functional coupling between neighboring receptors could improve the signaling performance. The ryanodine receptors (RyR)/calcium release channels usually form 2-D regular lattice in the endoplasmic/sarcoplasmic reticulum membranes. Thus, RyR is a potentially good model to study the function of receptor 2-D array. In this article, we briefly review recent progresses in this research field, including RyR-RyR interaction, RyR array's function and working mechanisms. The investigations performed by new methods in our laboratory are summarized. We demonstrate that the RyR-RyR interaction is modulated by the functional states of RyRs. Accordingly, the mechanism of "dynamic coupling" of RyR array is proposed. Its possible role in RyR-mediated Ca(2+) release is discussed.
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Calcio/metabolismo , Músculo Esquelético/metabolismo , Receptor Cross-Talk/fisiología , Canal Liberador de Calcio Receptor de Rianodina/fisiología , Animales , Cationes , Humanos , Músculo Esquelético/efectos de los fármacos , Retículo Sarcoplasmático/metabolismoRESUMEN
OBJECTIVE: To investigate the development and dynamic changes of host immune response in DBA/2 mice infected with Plasmodium yoelii 17XL. METHODS: Female DBA/2 mice were infected by intraperitoneal (i. p.) injection of 10(6) P. yoelii 17XL parasitized erythrocytes (PRBC). Levels of IL-12, IFN-gamma, IL-4, IL-10 and P. yoelii 17XL-specific antibody in sera were measured by ELISA. Concentrations of NO in cell supernatants were measured by the Griess reaction. Parasitemia, percentage of mononuclear-macrophages of individual mice were monitored daily, and phagocytosis of mononuclear macrophages was also observed. RESULTS: Primary parasitemia in vein blood was developed on day 3 postinfection, which peaked with a level of 46. 9% on day 9. Most mice cleared the infection and survived by day 20 postinfection. From day 6 to day 16, the phagocytosis of PRBC by rodent macrophages was observed on the blood smear. Infected mice had a continuously increased level of IL-12 in serum from day 1 postinfection. Accordingly, high level of IFN-gamma was also detected in sera from day 1 postinfection, which peaked on day 6. Infected mice produced higher level of IL-4 and IL-10 in serum on day 6 postinfection, which peaked on day 9 and day 15 postinfection respectively. In addition, splenocytes from infected mice produced significantly higher level of NO on day 6 and 20 postinfection. Level of P. yoelii 17XL-specific IgG was determined in the sera of infected mice with a steadily increased trend after infection, which peaked on day 70 postinfection. CONCLUSIONS: Effective polarizing of Th1 cells is significant in inhibition of parasitemia and eventual clearance of the Plasmodium parasites. Activated mononuclear-macrophages play a key role in inhibiting parasitemia in the early phase of infection with P. yoelii 17XL.