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1.
Neural Netw ; 177: 106386, 2024 May 10.
Artículo en Inglés | MEDLINE | ID: mdl-38776761

RESUMEN

In scenarios like privacy protection or large-scale data transmission, data-free knowledge distillation (DFKD) methods are proposed to learn Knowledge Distillation (KD) when data is not accessible. They generate pseudo samples by extracting the knowledge from teacher model, and utilize above pseudo samples for KD. The challenge in previous DFKD methods lies in the static nature of their target distributions and they focus on learning the instance-level distributions, causing its reliance on the pretrained teacher model. To address above concerns, our study introduces a novel DFKD approach known as AdaDFKD, designed to establish and utilize relationships among pseudo samples, which is adaptive to the student model, and finally effectively mitigates the aforementioned risk. We achieve this by generating from "easy-to-discriminate" samples to "hard-to-discriminate" samples as human does. We design a relationship refinement module (R2M) to optimize the generation process, wherein we learn a progressive conditional distribution of negative samples and maximize the log-likelihood of inter-sample similarity of pseudosamples. Theoretically, we discover that such design of AdaDFKD both minimize the divergence and maximize the mutual information between the distribution of teacher and student models. Above results demonstrate the superiority of our approach over state-of-the-art (SOTA) DFKD methods across various benchmarks, teacher-student pairs, and evaluation metrics, as well as robustness and fast convergence.

2.
Differentiation ; 135: 100744, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38128465

RESUMEN

Differentiation of human umbilical cord mesenchymal stem cells (Uc-MSCs) into islet-like clusters which are capable of synthesizing and secreting insulin can potentially serve as donors for islet transplantation in the patient deficiency in islet ß cell function both in type 1 or type 2 diabetic patients. Therefore, we developed an easy and higher efficacy approach by trypsinazing the Uc-MSCs and followed culture in differentiation medium to induce of Uc-MSCs differentiation into islet-like clusters, and the potential mechanism that in the early stage of differentiation was also investigated by using RNA-sequencing and bioinformatics. Results show that induction efficacy was reached to 98% and TGF-ß signaling pathway may play critical role in the early stage differentiation, it was further confirmed that the retardant effect of differentiation progress either in cell morphology or in islet specific genes expression can be observed upon blocking the activation of TGF-ß signaling pathway using specific inhibitor of LY2109761 (TßRI/II kinase inhibitor). Our current study, for the first time, development a protocol for differentiation of Uc-MSCs into islet-like clusters, and revealed the importance of TGF-ß signaling pathway in the early stage of differentiation of Uc-MSCs into islet-like clusters. Our study will provide alternative approach for clinical treatment of either type I or type II diabtes mellitus with dysfunctional pancreatic islets.


Asunto(s)
Células Secretoras de Insulina , Células Madre Mesenquimatosas , Humanos , Insulina , Tripsina/metabolismo , Diferenciación Celular/genética , Factor de Crecimiento Transformador beta/genética , Factor de Crecimiento Transformador beta/metabolismo , Transducción de Señal , Cordón Umbilical
3.
PLoS Biol ; 21(6): e3002142, 2023 06.
Artículo en Inglés | MEDLINE | ID: mdl-37289842

RESUMEN

Rab26 is known to regulate multiple membrane trafficking events, but its role in insulin secretion in pancreatic ß cells remains unclear despite it was first identified in the pancreas. In this study, we generated Rab26-/- mice through CRISPR/Cas9 technique. Surprisingly, insulin levels in the blood of the Rab26-/- mice do not decrease upon glucose stimulation but conversely increase. Deficiency of Rab26 promotes insulin secretion, which was independently verified by Rab26 knockdown in pancreatic insulinoma cells. Conversely, overexpression of Rab26 suppresses insulin secretion in both insulinoma cell lines and isolated mouse islets. Islets overexpressing Rab26, upon transplantation, also failed to restore glucose homeostasis in type 1 diabetic mice. Immunofluorescence microscopy revealed that overexpression of Rab26 results in clustering of insulin granules. GST-pulldown experiments reveal that Rab26 interacts with synaptotagmin-1 (Syt1) through directly binding to its C2A domain, which interfering with the interaction between Syt1 and SNAP25, and consequently inhibiting the exocytosis of newcomer insulin granules revealed by TIRF microscopy. Our results suggest that Rab26 serves as a negative regulator of insulin secretion, via suppressing insulin granule fusion with plasma membrane through sequestering Syt1.


Asunto(s)
Diabetes Mellitus Experimental , Células Secretoras de Insulina , Insulinoma , Islotes Pancreáticos , Neoplasias Pancreáticas , Animales , Ratones , Diabetes Mellitus Experimental/metabolismo , Exocitosis/fisiología , Glucosa/metabolismo , Insulina/metabolismo , Secreción de Insulina , Células Secretoras de Insulina/metabolismo , Insulinoma/metabolismo , Islotes Pancreáticos/metabolismo , Neoplasias Pancreáticas/metabolismo
4.
Adv Mater ; 34(42): e2206540, 2022 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-36085436

RESUMEN

The development of highly efficient and economical materials for the oxygen reduction reaction (ORR) plays a key role in practical energy conversion technologies. However, the intrinsic scaling relations exert thermodynamic inhibition on realizing highly active ORR electrocatalysts. Herein, a novel and feasible gradient orbital coupling strategy for tuning the ORR performance through the construction of Co 3d-O 2p-Eu 4f unit sites on the Eu2 O3 -Co model is proposed. Through the gradient orbital coupling, the pristine ionic property between Eu and O atoms is assigned with increased covalency, which optimizes the eg occupancy of Co sites, and weakens the OO bond, thus ultimately breaking the scaling relation between *OOH and *OH at Co-O-Eu unit sites. The optimized model catalyst displays onset and half-wave potential of 1.007 and 0.887 V versus reversible hydrogen electrode, respectively, which are higher than those of commercial Pt/C and most Co-based catalysts ever reported. In addition, the catalyst is found to possess superior selectivity and durability. It also reveals better cell performance than commercial noble-metal catalysts in Zn-air batteries in terms of high power/energy densities and long cycle life. This study provides a new perspective for electronic modulation strategy by the construction of gradient 3d-2p-4f orbital coupling.

5.
Chemistry ; 28(32): e202200664, 2022 Jun 07.
Artículo en Inglés | MEDLINE | ID: mdl-35384094

RESUMEN

An dual electronic and architectural engineering strategy is a good way to rationally design earth-abundant and highly efficient electrocatalysts of the oxygen evolution reaction (OER) for sustainable hydrogen-based energy devices. Here, a Ce-doped Co9 S8 core-shell nanoneedle array (Ce-Co9 S8 @CC) supported on a carbon cloth has been designed and developed to accelerate the sluggish kinetics of the OER. Profiting from valance alternative Ce doping, a fine core-shell structure and vertically aligned nanoneedle arrayed architecture, Ce-Co9 S8 @CC integrates modulated electronic structure, highly exposed active sites, and multidimensional mass diffusion channels; together, these afford a favorable catalyzed OER. Ce-Co9 S8 @CC exhibits remarkable performance in the OER in an alkaline medium, where the overpotential requires only 242 mV to deliver a current density of 10 mA cm-2 for the OER; this is 70 mV superior to that of Ce-free Co9 S8 catalyst and other counterparts. Good stability and impressive selectivity (nearly 100 % Faradic efficiency) are also demonstrated. When integrated into a two-electrode OER//HER electrolyzer, the as-prepared Ce-Co9 S8 @CC displays a low operation potential of 1.54 V at 10 mA cm-2 and long-term stability, thus demonstrating great potential for economical water electrolysis.

6.
Rev Sci Instrum ; 92(10): 104501, 2021 Oct 01.
Artículo en Inglés | MEDLINE | ID: mdl-34717411

RESUMEN

Errors in the attitude of optical payloads onboard remote-sensing satellites have a significant impact on image quality and high-precision quantification. This study presents two on-orbit calibration techniques for optical payloads. Self-calibration of the orientation of the optical axis of an optical payload can be achieved through on-orbit observation and imaging of star points based on the pinhole imaging principle. Separate on-orbit observation and imaging of star points can facilitate the mutual calibration of an optical payload and a star sensor as well as the correction of their installation errors. These two techniques are validated through ground and on-orbit satellite tests. The results show the following: The self-calibration error for a typical remote-sensing satellite is better than 0.2″ and the mutual-calibration error is better than 2″ for its optical payload and star sensor. Self-calibration and mutual calibration are effective for improving the calibration accuracy for the on-orbit orientation of optical payloads.

7.
Diabetes ; 69(1): 67-82, 2020 01.
Artículo en Inglés | MEDLINE | ID: mdl-31624142

RESUMEN

Insulin secretion is tightly regulated by membrane trafficking. RILP (Rab7 interacting lysosomal protein) regulates the endocytic trafficking, but its role in insulin secretion has not been investigated. In this study, we found that overexpression of RILP inhibited insulin secretion in both the ß-cell lines and freshly isolated islets. Consequently, the expression of RILP in islets suppressed the ability to recover the glucose homeostasis in type 1 diabetes mice upon transplantation. Of physiological relevance is that RILP expression was upregulated in the diabetic mouse islets. Mechanistically, overexpression of RILP induced insulin granule clustering, decreased the number of proinsulin-containing granules in ß-cells, and significantly promoted proinsulin degradation. Conversely, RILP depletion sustained proinsulin and increased insulin secretion. The proinsulin degradation induced by RILP expression was inhibited by lysosomal inhibitors and was Rab7-dependent. Finally, we showed that RILP interacts with insulin granule-associated Rab26 to restrict insulin secretion. This study presents a new pathway regulating insulin secretion and mechanically demonstrates a novel function of RILP in modulating insulin secretion through mediating the lysosomal degradation of proinsulin.


Asunto(s)
Proteínas Adaptadoras Transductoras de Señales/fisiología , Secreción de Insulina/genética , Células Secretoras de Insulina/metabolismo , Lisosomas/metabolismo , Proinsulina/metabolismo , Animales , Células Cultivadas , Células HEK293 , Humanos , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Transgénicos , Proteolisis , Ratas , Ratas Sprague-Dawley
8.
Biochem Pharmacol ; 174: 113785, 2020 04.
Artículo en Inglés | MEDLINE | ID: mdl-31887289

RESUMEN

Regeneration of ß-cells by differentiation of pancreatic progenitor cells has the potential to fundamentally solve the problems of the loss of ß-cell function and mass during disease progression in both type 1 or 2 diabetes. Therefore, discovery of novel differentiation inducers to promote islet regeneration is of great significance. Pancreatic and duodenal homeobox1 (PDX-1) is a key transcription factor that promotes the development and maturation of pancreatic ß-cells. To screen potential novel small molecules for enhancing differentiation of PNAC-1 cells, a human pancreatic ductal cell lines into insulin-producing cells (IPCs), we developed a high-throughput screening method through fusing the PDX-1 promoter region with a luciferase reporter gene. We screened and identified that andrographolide named C1037 stimulates PDX-1 expression in both mRNA and protein level and significantly promotes PANC-1 cells differentiation into IPCs as compared with that of control cells. The therapeutic effect of C037 in Streptozotocin induced diabetic mouse model through differentiation of pancreatic ductal cells into insulin positive islets was also observed. Our study provides a novel method to screen compounds regulating the differentiation of pancreatic progenitor cells having the potential of enhancing islet regeneration for diabetes therapy.


Asunto(s)
Diferenciación Celular/efectos de los fármacos , Diterpenos/farmacología , Proteínas de Homeodominio/metabolismo , Hipoglucemiantes/farmacología , Secreción de Insulina/efectos de los fármacos , Células Secretoras de Insulina/efectos de los fármacos , Conductos Pancreáticos/efectos de los fármacos , Transactivadores/metabolismo , Andrographis/química , Animales , Técnicas de Cultivo de Célula , Diferenciación Celular/genética , Línea Celular , Diabetes Mellitus Experimental/tratamiento farmacológico , Diabetes Mellitus Experimental/metabolismo , Diabetes Mellitus Tipo 1/tratamiento farmacológico , Diabetes Mellitus Tipo 1/metabolismo , Diterpenos/aislamiento & purificación , Diterpenos/uso terapéutico , Expresión Génica/efectos de los fármacos , Prueba de Tolerancia a la Glucosa , Proteínas de Homeodominio/genética , Humanos , Hipoglucemiantes/aislamiento & purificación , Hipoglucemiantes/uso terapéutico , Células Secretoras de Insulina/metabolismo , Masculino , Ratones , Conductos Pancreáticos/metabolismo , Transactivadores/genética
9.
J Tradit Chin Med ; 39(2): 191-198, 2019 04.
Artículo en Inglés | MEDLINE | ID: mdl-32186041

RESUMEN

OBJECTIVE: To determine the therapeutic effect and potential mechanism of Huatan Tongluo decoction on rats with collagen-induced arthritis. METHODS: Forty specific pathogen-free Wistar rats were selected, and 10 were randomly selected as the control (group 1). The remaining rats were injected intradermally with emulsified type II bovine collagen at the tail base and back, followed by a booster 7 d post first immunization. After establishing collagen-induced arthritis (CIA), rats were randomly divided into three groups (n = 10). The rats were treated orally for 30 d as follows: group 1, saline; group 2, model (saline); group 3, tripterygium polyglycoside (TP; 7.81 mg/kg, positive control); group 4, Huatan Tongluo decoction (HTTL; 7.5 g/kg). Body weight, ankle swelling and arthritis index were measured over the course of the study. The rats were sacrificed 30 d after treatment. Morphological changes in the synovium were observed by hematoxylin and eosin staining. Pannus formation and synovial thickness in the left ankle were observed by color Doppler ultrasoundVascular endothelial growth factor (VEGF) and VEGFR2 protein levels were measured by immunohistochemistry. VEGF/VEGFR2 mRNA levels were measured by real-time quantitative polymerase chain reaction. RESULTS: Compared with the model group, a significantly lower arthritis index was observed in the positive control group (P < 0.05) and HTTL group (P < 0.01), after treatment. Both positive control and HTTL reduced intra-articular pannus formation and synovial thickening. Furthermore, VEGF mRNA, and VEGFR2 protein and mRNA levels were significantly downregulated (P < 0.05) in the treatment groups. CONCLUSION: Inhibition of the expression of VEGF and VEGFR2 in synovial tissues and the formation of pannus and synovial hyperplasia may be part of the mechanism of HTTL for relieving the symptoms of rheumatoid arthritis in CIA rats.


Asunto(s)
Artritis Experimental/metabolismo , Artritis Experimental/patología , Medicamentos Herbarios Chinos/farmacología , Regulación de la Expresión Génica/efectos de los fármacos , Membrana Sinovial/efectos de los fármacos , Membrana Sinovial/patología , Receptor 2 de Factores de Crecimiento Endotelial Vascular/metabolismo , Animales , Antígenos CD34/metabolismo , Artritis Experimental/genética , Medicamentos Herbarios Chinos/uso terapéutico , Masculino , ARN Mensajero/genética , Ratas , Ratas Wistar , Membrana Sinovial/metabolismo , Factor A de Crecimiento Endotelial Vascular/genética , Receptor 2 de Factores de Crecimiento Endotelial Vascular/genética
10.
Traffic ; 18(12): 767-775, 2017 12.
Artículo en Inglés | MEDLINE | ID: mdl-28857378

RESUMEN

SNAREs are the core machinery mediating membrane fusion. In this review, we provide an update on the recent progress on SNAREs regulating membrane fusion events, especially the more detailed fusion processes dissected by well-developed biophysical methods and in vitro single molecule analysis approaches. We also briefly summarize the relevant research from Chinese laboratories and highlight the significant contributions on our understanding of SNARE-mediated membrane trafficking from scientists in China.


Asunto(s)
Membrana Celular/metabolismo , Fusión de Membrana/fisiología , Transporte de Proteínas/fisiología , Proteínas SNARE/metabolismo , Proteínas de Transporte Vesicular/metabolismo , Movimiento Celular/fisiología , Humanos
11.
Acta Pharmacol Sin ; 36(10): 1212-8, 2015 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-26073330

RESUMEN

Alternative splicing is a key process of multi-exonic gene expression during pre-mRNA maturation. In this process, particular exons of a gene will be included within or excluded from the final matured mRNA, and the resulting transcripts generate diverse protein isoforms. Recent evidence demonstrates that approximately 95% of human genes with multiple exons undergo alternative splicing during pre-mRNA maturation. Thus, alternative splicing plays a critical role in physiological processes and cell development programs, and.dysregulation of alternative splicing is highly associated with human diseases, such as cancer, diabetes and neurodegenerative diseases. In this review, we discuss the regulation of alternative splicing, examine the relationship between alternative splicing and human diseases, and describe several approaches that modify alternative splicing, which could aid in human disease diagnosis and therapy.


Asunto(s)
Empalme Alternativo , Diabetes Mellitus/genética , Descubrimiento de Drogas , Neoplasias/genética , Enfermedades Neurodegenerativas/genética , ARN Mensajero/genética , Empalme Alternativo/efectos de los fármacos , Animales , Diabetes Mellitus/tratamiento farmacológico , Descubrimiento de Drogas/métodos , Marcadores Genéticos/genética , Humanos , Terapia Molecular Dirigida/métodos , Neoplasias/tratamiento farmacológico , Enfermedades Neurodegenerativas/tratamiento farmacológico
12.
Diabetes ; 63(5): 1612-23, 2014 May.
Artículo en Inglés | MEDLINE | ID: mdl-24379354

RESUMEN

Pancreatic ß-cell dysfunction is a common feature of type 2 diabetes. Earlier, we had cloned IG20 cDNA from a human insulinoma and had shown that IG20/MADD can encode six different splice isoforms that are differentially expressed and have unique functions, but its role in ß-cell function was unexplored. To investigate the role of IG20/MADD in ß-cell function, we generated conditional knockout (KMA1ko) mice. Deletion of IG20/MADD in ß-cells resulted in hyperglycemia and glucose intolerance associated with reduced and delayed glucose-induced insulin production. KMA1ko ß-cells were able to process insulin normally but had increased insulin accumulation and showed a severe defect in glucose-induced insulin release. These findings indicated that IG20/MADD plays a critical role in glucose-induced insulin release from ß-cells and that its functional disruption can cause type 2 diabetes. The clinical relevance of these findings is highlighted by recent reports of very strong association of the rs7944584 single nucleotide polymorphism (SNP) of IG20/MADD with fasting hyperglycemia/diabetes. Thus, IG20/MADD could be a therapeutic target for type 2 diabetes, particularly in those with the rs7944584 SNP.


Asunto(s)
Proteínas Adaptadoras de Señalización del Receptor del Dominio de Muerte/metabolismo , Diabetes Mellitus Tipo 2/metabolismo , Glucosa/metabolismo , Factores de Intercambio de Guanina Nucleótido/metabolismo , Hiperglucemia/metabolismo , Insulina/metabolismo , Animales , Apoptosis/fisiología , Proteínas Adaptadoras de Señalización del Receptor del Dominio de Muerte/genética , Diabetes Mellitus Tipo 2/genética , Prueba de Tolerancia a la Glucosa , Factores de Intercambio de Guanina Nucleótido/genética , Hiperglucemia/genética , Resistencia a la Insulina/fisiología , Secreción de Insulina , Células Secretoras de Insulina/metabolismo , Ratones , Ratones Noqueados
13.
J Autoimmun ; 52: 64-73, 2014 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-24388113

RESUMEN

Myasthenia gravis (MG) is an autoimmune disorder caused by target-specific pathogenic antibodies directed toward postsynaptic neuromuscular junction (NMJ) proteins, most commonly the skeletal muscle nicotinic acetylcholine receptor (AChR). In MG, high-affinity anti-AChR Abs binding to the NMJ lead to loss of functional AChRs, culminating in neuromuscular transmission failure and myasthenic symptoms. Intravenous immune globulin (IVIg) has broad therapeutic application in the treatment of a range of autoimmune diseases, including MG, although its mechanism of action is not clear. Recently, the anti-inflammatory and anti-autoimmune activities of IVIg have been attributed to the IgG Fc domains. Soluble immune aggregates bearing intact Fc fragments have been shown to be effective treatment for a number of autoimmune disorders in mice, and fully recombinant multimeric Fc molecules have been shown to be effective in treating collagen-induced arthritis, murine immune thrombocytopenic purpura, and experimental inflammatory neuritis. In this study, a murine model of MG (EAMG) was used to study the effectiveness of this novel recombinant polyvalent IgG2a Fc (M045) in treating established myasthenia, with a direct comparison to treatment with IVIg. M045 treatment had profound effects on the clinical course of EAMG, accompanied by down-modulation of pathogenic antibody responses. These effects were associated with reduced B cell activation and T cell proliferative responses to AChR, an expansion in the population of FoxP3(+) regulatory T cells, and enhanced production of suppressive cytokines, such as IL-10. Treatment was at least as effective as IVIg in suppressing EAMG, even at doses 25-30 fold lower. Multimeric Fc molecules offer the advantages of being recombinant, homogenous, available in unlimited quantity, free of risk from infection and effective at significantly reduced protein loads, and may represent a viable therapeutic alternative to polyclonal IVIg.


Asunto(s)
Linfocitos B/efectos de los fármacos , Fragmentos Fc de Inmunoglobulinas/administración & dosificación , Inmunoterapia/métodos , Miastenia Gravis Autoinmune Experimental/terapia , Linfocitos T Reguladores/efectos de los fármacos , Animales , Autoanticuerpos/sangre , Linfocitos B/inmunología , Proliferación Celular/efectos de los fármacos , Células Cultivadas , Femenino , Humanos , Inmunidad Humoral/efectos de los fármacos , Fragmentos Fc de Inmunoglobulinas/genética , Inmunoglobulina G/genética , Inmunoglobulinas Intravenosas/administración & dosificación , Interleucina-10/metabolismo , Activación de Linfocitos/efectos de los fármacos , Ratones , Ratones Endogámicos C57BL , Miastenia Gravis Autoinmune Experimental/inmunología , Receptores Colinérgicos/inmunología , Proteínas Recombinantes/genética , Linfocitos T Reguladores/inmunología
14.
J Cell Biochem ; 115(2): 261-70, 2014 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-24038283

RESUMEN

Mitogen-activated kinase activating death domain containing protein (MADD) is abundantly expressed in cancer cells and necessary for maintaining cancer cell survival. However, this survival function of MADD is dependent upon its phosphorylation by protein kinase B (Akt). The tumour suppressor PTEN (phosphatase and tensin homolog deleted on chromosome 10) is a lipid phosphatase that negatively regulates the phosphatidylinositol 3-kinase (PI3K)-Akt signaling pathway. The downstream targets of PTEN in triggering apoptosis have not yet been completely identified. Here, we report that MADD can act as a pro-apoptotic factor to initiate TRAIL-induced apoptosis when its phosphorylation is attenuated by PTEN. Our data show that tumor necrosis factor α-related apoptosis-inducing ligand (TRAIL) induced a reduction in MADD phosphorylation with a concomitant up-regulation of PTEN. Knock down of PTEN using a specific siRNA prevented TRAIL-induced reduction in pMADD levels. Surprisingly, Akt non-phosphorylated MADD translocated from the plasma membrane to cytoplasm where it bound to 14-3-3 and displaced 14-3-3 associated Bax, which translocated to mitochondria resulting in cytochrome c release. Taken together, our data reveal that PTEN can convey the death signal by preventing MADD phosphorylation by Akt.


Asunto(s)
Apoptosis/genética , Proteínas Adaptadoras de Señalización del Receptor del Dominio de Muerte/metabolismo , Factores de Intercambio de Guanina Nucleótido/metabolismo , Fosfohidrolasa PTEN/metabolismo , Factor de Necrosis Tumoral alfa/metabolismo , Proteínas 14-3-3/metabolismo , Línea Celular Tumoral , Proteínas Adaptadoras de Señalización del Receptor del Dominio de Muerte/genética , Factores de Intercambio de Guanina Nucleótido/genética , Humanos , Mitocondrias/metabolismo , Fosfohidrolasa PTEN/genética , Fosfatidilinositol 3-Quinasas/genética , Fosfatidilinositol 3-Quinasas/metabolismo , Fosforilación , Proteínas Proto-Oncogénicas c-akt/genética , Proteínas Proto-Oncogénicas c-akt/metabolismo , ARN Interferente Pequeño , Factor de Necrosis Tumoral alfa/genética
15.
PLoS One ; 8(2): e56817, 2013.
Artículo en Inglés | MEDLINE | ID: mdl-23457619

RESUMEN

The Map kinase Activating Death Domain containing protein (MADD) isoform of the IG20 gene is over-expressed in different types of cancer tissues and cell lines and it functions as a negative regulator of apoptosis. Therefore, we speculated that MADD might be over-expressed in human breast cancer tissues and that MADD knock-down might synergize with chemotherapeutic or TRAIL-induced apoptosis of breast cancer cells. Analyses of breast tissue microarrays revealed over-expression of MADD in ductal and invasive carcinomas relative to benign tissues. MADD knockdown resulted in enhanced spontaneous apoptosis in human breast cancer cell lines. Moreover, MADD knockdown followed by treatment with TRAIL or doxorubicin resulted in increased cell death compared to either treatment alone. Enhanced cell death was found to be secondary to increased caspase-8 activation. These data indicate that strategies to decrease MADD expression or function in breast cancer may be utilized to increase tumor cell sensitivity to TRAIL and doxorubicin induced apoptosis.


Asunto(s)
Apoptosis/efectos de los fármacos , Neoplasias de la Mama/patología , Proteínas Adaptadoras de Señalización del Receptor del Dominio de Muerte/deficiencia , Proteínas Adaptadoras de Señalización del Receptor del Dominio de Muerte/genética , Doxorrubicina/farmacología , Técnicas de Silenciamiento del Gen , Factores de Intercambio de Guanina Nucleótido/deficiencia , Factores de Intercambio de Guanina Nucleótido/genética , Ligando Inductor de Apoptosis Relacionado con TNF/farmacología , Secuencia de Aminoácidos , Antineoplásicos/farmacología , Línea Celular Tumoral , Proteínas Adaptadoras de Señalización del Receptor del Dominio de Muerte/química , Regulación Neoplásica de la Expresión Génica/efectos de los fármacos , Factores de Intercambio de Guanina Nucleótido/química , Humanos , Datos de Secuencia Molecular , ARN Interferente Pequeño/genética , Receptores de Muerte Celular/metabolismo
16.
Thyroid ; 23(1): 70-8, 2013 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-22998497

RESUMEN

BACKGROUND: The IG20/MADD gene is overexpressed in thyroid cancer tissues and cell lines, and can contribute to tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) resistance. The ability of the MADD protein to resist TRAIL-induced apoptosis is dependent upon its phosphorylation by Akt. Interestingly, while TRAIL induces a significant reduction in the levels of phospho-Akt (pAkt) and phospho-MADD (pMADD) in TRAIL-sensitive cells, it fails to do so in TRAIL-resistant cells. In this study, we investigated if MADD phosphorylation by Akt was contributing to TRAIL resistance in thyroid cancer cells. METHODS: We determined the susceptibility of different thyroid cancer cell lines to TRAIL-induced apoptosis by fluorescence-activated cell sorting (FACS) analysis. We tested for various TRAIL resistance factors by FACS analyses or for IG20/MADD expression by quantitative reverse transcription-polymerase chain reaction. We determined the levels of pAkt and pMADD upon TRAIL treatment in thyroid cancer cells by Western blotting. We tested if down-modulation of IG20/MADD gene expression using shRNA or phosphorylation using a dominant negative Akt (DN-Akt) or pretreatment with LY294002, a PI3 kinase inhibitor, could help overcome TRAIL resistance. RESULT: BCPAP and TPC1 cells were susceptible, while KTC1 and FTC133 cells were resistant, to TRAIL-induced apoptosis. The differential susceptibility to TRAIL was not related to the levels of expression of death receptors, decoy receptors, or TRAIL. KTC1 and FTC133 cells showed higher levels of IG20/MADD expression relative to BCPAP and TPC1, and were rendered susceptible to TRAIL treatment upon IG20/MADD knockdown. Interestingly, upon TRAIL treatment, the pAkt and pMADD levels were reduced in TRAIL-sensitive BCPAP and TPC1 cells, while they remained unchanged in the resistant KTC1 and FTC133 cells. While expression of a constitutively active Akt in BCPAP and TPC1 cells rendered them resistant to TRAIL, pretreating KTC1 and FTC133 cells with LY294002 rendered them TRAIL-sensitive. Moreover, expression of a DN-Akt in KTC1 and FTC133 cells reduced the levels of pAkt and pMADD and sensitized them to TRAIL-induced apoptosis. CONCLUSION: Our results show that pMADD is an important TRAIL resistance factor in certain thyroid cancer cells and suggest that down-modulation of either IG20/MADD expression or phosphorylation can render TRAIL-resistant thyroid cancer cells sensitive to TRAIL.


Asunto(s)
Proteínas Adaptadoras de Señalización del Receptor del Dominio de Muerte/antagonistas & inhibidores , Proteínas Adaptadoras de Señalización del Receptor del Dominio de Muerte/genética , Factores de Intercambio de Guanina Nucleótido/antagonistas & inhibidores , Factores de Intercambio de Guanina Nucleótido/genética , Ligando Inductor de Apoptosis Relacionado con TNF/farmacología , Neoplasias de la Tiroides/tratamiento farmacológico , Apoptosis/efectos de los fármacos , Línea Celular Tumoral , Cromonas/farmacología , Proteínas Adaptadoras de Señalización del Receptor del Dominio de Muerte/metabolismo , Resistencia a Antineoplásicos , Inhibidores Enzimáticos/farmacología , Técnicas de Silenciamiento del Gen , Factores de Intercambio de Guanina Nucleótido/metabolismo , Humanos , Morfolinas/farmacología , Inhibidores de las Quinasa Fosfoinosítidos-3 , Fosforilación , Proteínas Proto-Oncogénicas c-akt/antagonistas & inhibidores , Proteínas Proto-Oncogénicas c-akt/metabolismo , ARN Interferente Pequeño/genética , Receptores de Muerte Celular/genética , Proteínas Recombinantes/farmacología , Neoplasias de la Tiroides/genética , Neoplasias de la Tiroides/metabolismo , Neoplasias de la Tiroides/patología , Receptores Señuelo del Factor de Necrosis Tumoral/genética
17.
Am J Obstet Gynecol ; 205(4): 362.e12-25, 2011 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-21855847

RESUMEN

OBJECTIVE: The clinical utility of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) in the treatment of established human malignancies is limited by the development of resistance to TRAIL. We hypothesized that knockdown of map-kinase activating death domain containing protein (MADD), a TRAIL-resistance factor, may overcome TRAIL resistance in ovarian cancer cells. STUDY DESIGN: MADD expression in resected ovarian cancer specimens and cell lines was quantified with the use of polymerase chain reaction. Sensitivity of ovarian cancer cell lines to TRAIL, with or without MADD knockdown, was assessed. RESULTS: MADD is expressed at relatively higher levels in human malignant ovarian cancer tissues and cell lines, compared with normal ovarian tissues. The cell lines OVCA429 and OVCAR3 were susceptible, and cell lines CAOV-3 and SKOV-3 were resistant to TRAIL. MADD knockdown in CAOV-3 cells, but not in SKOV-3 cells, conferred TRAIL sensitivity. Knockdown of cellular Fas-associated death domain-like interleukin-1 beta-converting enzyme-inhibitory protein (c-FLIP) in SKOV-3 cells increased spontaneous and TRAIL-induced apoptosis, which was further increased on MADD knockdown. CONCLUSION: MADD/c-FLIP(L) knockdown can render TRAIL-resistant ovarian cancer cells susceptible to TRAIL.


Asunto(s)
Apoptosis/fisiología , Proteína Reguladora de Apoptosis Similar a CASP8 y FADD/fisiología , Proteínas Adaptadoras de Señalización del Receptor del Dominio de Muerte/fisiología , Factores de Intercambio de Guanina Nucleótido/fisiología , Neoplasias Ováricas/patología , Ligando Inductor de Apoptosis Relacionado con TNF/fisiología , Femenino , Humanos , Células Tumorales Cultivadas
18.
Sheng Wu Yi Xue Gong Cheng Xue Za Zhi ; 26(1): 184-6, 2009 Feb.
Artículo en Chino | MEDLINE | ID: mdl-19334582

RESUMEN

The recent fast development in biotechnology has resulted in a large number of therapeutic biologicals coming in the foreground for clinical application. Transdermal drug delivery (TDD) is designed for patching the drug on the skin, and then the drug molecules permeate through the skin into the subcutaneous capillary vessels. However,very few drugs can be administered transdermally at the therapeutic levels to pass through the barrier of stratum corneum. Several physical and chemical methods are applied to improve the permeability of skin. Research result shows that the low-frequency ultrasonic technique can extraordinarily increase the rate of permeation. As a result, it is becoming one of the potential methods that serve as the substitutes for traditional methods. In this paper is presented a type of equipment based on MSP430. The principle of design, the structure of hardware, and the applied function in this area are described.


Asunto(s)
Sistemas de Liberación de Medicamentos/instrumentación , Preparaciones Farmacéuticas/administración & dosificación , Absorción Cutánea/efectos de la radiación , Ultrasonido , Administración Cutánea , Sistemas de Liberación de Medicamentos/métodos , Diseño de Equipo , Humanos
19.
Ann N Y Acad Sci ; 1132: 276-82, 2008.
Artículo en Inglés | MEDLINE | ID: mdl-18567878

RESUMEN

Current treatments for myasthenia gravis (MG) rely upon the administration of immunosuppressive agents which result in global, nonspecific attenuation of the immune response. An alternative approach would be to attempt to design therapies that specifically dampen autoreactivity without affecting general immunity. Recently, dendritic cells (DCs) have been shown to possess potent capabilities to tolerize T cells in an antigen-specific manner. We have observed that the selective activation of particular subsets of DCs utilizing granulocyte-macrophage colony-stimulating factor (GM-CSF) had profound effects on the induction of experimental autoimmune myasthenia gravis (EAMG). Specifically, treatment with GM-CSF effectively suppressed the induction of EAMG and down-modulated anti-AChR T cell and pathogenic antibody responses. These effects were associated with the activation of tolerogenic DCs, the enhanced production of suppressive cytokines, such as IL-10, and the mobilization of CD4(+)CD25(+) and FoxP3(+) regulatory T cells (Tregs). We have further shown that GM-CSF effectively ameliorates clinical disease severity in mice with active, ongoing EAMG. Based on these observations, we hypothesize that the selective activation of particular DC subsets in vivo using pharmacologic agents, like GM-CSF, can suppress ongoing anti-AChR immune responses by mobilizing antigen-specific Tregs capable of suppressing autoimmune MG.


Asunto(s)
Autoinmunidad/inmunología , Miastenia Gravis Autoinmune Experimental/inmunología , Animales , Células Dendríticas/inmunología , Factor Estimulante de Colonias de Granulocitos y Macrófagos/inmunología , Humanos , Tolerancia Inmunológica/inmunología
20.
J Immunol ; 177(8): 5296-306, 2006 Oct 15.
Artículo en Inglés | MEDLINE | ID: mdl-17015715

RESUMEN

Dendritic cells (DCs) have the potential to activate or tolerize T cells in an Ag-specific manner. Although the precise mechanism that determines whether DCs exhibit tolerogenic or immunogenic functions has not been precisely elucidated, growing evidence suggests that DC function is largely dependent on differentiation status, which can be manipulated using various growth factors. In this study, we investigated the effects of mobilization of specific DC subsets-using GM-CSF and fms-like tyrosine kinase receptor 3-ligand (Flt3-L)-on the susceptibility to induction of experimental autoimmune myasthenia gravis (EAMG). We administered GM-CSF or Flt3-L to C57BL/6 mice before immunization with acetylcholine receptor (AChR) and observed the effect on the frequency and severity of EAMG development. Compared with AChR-immunized controls, mice treated with Flt3-L before immunization developed EAMG at an accelerated pace initially, but disease frequency and severity was comparable at the end of the observation period. In contrast, GM-CSF administered before immunization exerted a sustained suppressive effect against the induction of EAMG. This suppression was associated with lowered serum autoantibody levels, reduced T cell proliferative responses to AChR, and an expansion in the population of FoxP3+ regulatory T cells. These results highlight the potential of manipulating DCs to expand regulatory T cells for the control of autoimmune diseases such as MG.


Asunto(s)
Proliferación Celular/efectos de los fármacos , Factores de Transcripción Forkhead , Factor Estimulante de Colonias de Granulocitos y Macrófagos/farmacología , Miastenia Gravis Autoinmune Experimental/prevención & control , Linfocitos T Reguladores/citología , Animales , Enfermedades Autoinmunes/terapia , Comunicación Celular/inmunología , Células Dendríticas/efectos de los fármacos , Células Dendríticas/inmunología , Factor Estimulante de Colonias de Granulocitos y Macrófagos/administración & dosificación , Inmunización , Proteínas de la Membrana/administración & dosificación , Proteínas de la Membrana/farmacología , Ratones , Ratones Endogámicos C57BL , Miastenia Gravis Autoinmune Experimental/inmunología , Miastenia Gravis Autoinmune Experimental/terapia , Receptores Colinérgicos/administración & dosificación , Receptores Colinérgicos/inmunología
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