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1.
Hong Kong Med J ; 30(2): 147-162, 2024 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-38590158

RESUMEN

This project was undertaken to develop the first set of consensus statements regarding the management of pancreatic ductal adenocarcinoma (PDAC) in Hong Kong, with the goal of providing guidance to local clinicians. A multidisciplinary panel of experts discussed issues surrounding current PDAC management and reviewed evidence gathered in the local context to propose treatment recommendations. The experts used the Delphi approach to finalise management recommendations. Consensus was defined as ≥80% acceptance among all expert panel members. Thirty-nine consensus statements were established. These statements cover all aspects of PDAC management, including diagnosis, resectability criteria, treatment modalities according to resectability, personalised management based on molecular profiling, palliative care, and supportive care. This project fulfils the need for guidance regarding PDAC management in Hong Kong. To assist clinicians with treatment decisions based on varying levels of evidence and clinical experience, treatment options are listed in several consensus statements.

2.
Lung ; 199(6): 597-602, 2021 12.
Artículo en Inglés | MEDLINE | ID: mdl-34797407

RESUMEN

PURPOSE: Gastro-oesophageal reflux disease (GORD) is commonly thought to play an important role in chronic cough and patients are often empirically treated with acid suppression therapy. We sought to investigate the response rate to acid suppression treatment in patients with and without heartburn attending two specialist cough clinics. METHODS: A retrospective review of 558 consecutive patients referred to two specialist cough clinics was performed (UK and USA). Patients who were treated with acid suppression were included and their documented response to treatment was collected. Binary logistic regression was used to ascertain the value of reported heartburn in predicting the response of chronic cough to acid suppression therapy. RESULTS: Of 558 consecutive referrals, 238 patients were excluded due to missing data or cough duration of < 8 weeks. The remaining 320 patients were predominantly female (76%), with mean age 61 yrs (± 13) and 96.8% non-smokers, with chronic cough for 36 (18-117) months. Of 72 patients with heartburn, 20 (28%) noted improvement in their cough with acid suppression, whereas of 248 without heartburn, only 35 (14%) responded. Patients reporting heartburn were 2.7 (95% C.I. 1.3-5.6) times more likely to respond to acid suppression therapy (p = 0.007). CONCLUSION: In specialist cough clinics, few patients report a response of their chronic cough to acid suppression therapy. Nonetheless, heartburn is a useful predictor substantially increasing the likelihood of benefit.


Asunto(s)
Reflujo Gastroesofágico , Pirosis , Enfermedad Crónica , Tos/tratamiento farmacológico , Femenino , Reflujo Gastroesofágico/complicaciones , Reflujo Gastroesofágico/tratamiento farmacológico , Pirosis/tratamiento farmacológico , Humanos , Persona de Mediana Edad , Estudios Retrospectivos
3.
Diabet Med ; 35(7): 929-936, 2018 07.
Artículo en Inglés | MEDLINE | ID: mdl-29633347

RESUMEN

AIM: We developed and implemented a national audit and benchmarking programme to describe the clinical status of people with diabetes attending specialist diabetes services in Australia. METHODS: The Australian National Diabetes Information Audit and Benchmarking (ANDIAB) initiative was established as a quality audit activity. De-identified data on demographic, clinical, biochemical and outcome items were collected from specialist diabetes services across Australia to provide cross-sectional data on people with diabetes attending specialist centres at least biennially during the years 1998 to 2011. RESULTS: In total, 38 155 sets of data were collected over the eight ANDIAB audits. Each ANDIAB audit achieved its primary objective to collect, collate, analyse, audit and report clinical diabetes data in Australia. Each audit resulted in the production of a pooled data report, as well as individual site reports allowing comparison and benchmarking against other participating sites. CONCLUSIONS: The ANDIAB initiative resulted in the largest cross-sectional national de-identified dataset describing the clinical status of people with diabetes attending specialist diabetes services in Australia. ANDIAB showed that people treated by specialist services had a high burden of diabetes complications. This quality audit activity provided a framework to guide planning of healthcare services.


Asunto(s)
Benchmarking , Complicaciones de la Diabetes , Diabetes Mellitus/terapia , Dietoterapia , Planificación en Salud , Hipoglucemiantes/uso terapéutico , Auditoría Médica , Calidad de la Atención de Salud , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Antihipertensivos/uso terapéutico , Australia , Estudios Transversales , Bases de Datos Factuales , Conjuntos de Datos como Asunto , Femenino , Humanos , Hipolipemiantes/uso terapéutico , Masculino , Persona de Mediana Edad , Adulto Joven
4.
J Physiol ; 594(20): 5823-5837, 2016 10 15.
Artículo en Inglés | MEDLINE | ID: mdl-26913808

RESUMEN

Brain Cav 1.2 and Cav 1.3 L-type Ca2+ channels play key physiological roles in various neuronal processes that contribute to brain function. Genetic studies have recently identified CACNA1C as a candidate risk gene for bipolar disorder (BD), schizophrenia (SCZ), major depressive disorder (MDD) and autism spectrum disorder (ASD), and CACNA1D for BD and ASD, suggesting a contribution of Cav 1.2 and Cav 1.3 Ca2+ signalling to the pathophysiology of neuropsychiatric disorders. Once considered sole clinical entities, it is now clear that BD, SCZ, MDD and ASD share common phenotypic features, most likely due to overlapping neurocircuitry and common molecular mechanisms. A major future challenge lies in translating the human genetic findings to pathological mechanisms that are translatable back to the patient. One approach for tackling such a daunting scientific endeavour for complex behaviour-based neuropsychiatric disorders is to examine intermediate biological phenotypes in the context of endophenotypes within distinct behavioural domains. This will better allow us to integrate findings from genes to behaviour across species, and improve the chances of translating preclinical findings to clinical practice.


Asunto(s)
Afecto/fisiología , Conducta Adictiva/metabolismo , Conducta Adictiva/fisiopatología , Canales de Calcio Tipo L/metabolismo , Cognición/fisiología , Animales , Endofenotipos/metabolismo , Humanos
5.
Curr Oncol ; 23(5): 298-303, 2016 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-27803593

RESUMEN

INTRODUCTION: BRCA mutation testing allows index patients and their families to be provided with appropriate cancer risk-reduction strategies. Because of the low prevalence of BRCA mutations in unselected breast cancer patients and the high cost of genetic testing, it is important to identify the subset of women who are likely to carry BRCA mutations. In the present study, we examined the association between BRCA1/2 germline mutations and the immunohistochemical features of breast cancer. METHODS: In a retrospective review of 498 breast cancer patients who had undergone BRCA testing at Seoul National University Bundang Hospital between July 2003 and September 2012, we gathered immunohistochemical information on estrogen receptor (er), progesterone receptor (pr), her2 (human epidermal growth factor receptor 2), cytokeratin 5/6, egfr (epidermal growth factor receptor), and p53 status. RESULTS: Among the 411 patients eligible for the study, 50 (12.2%) had germline mutations in BRCA1 or BRCA2. Of the 93 patients with triple-negative breast cancer (tnbc), 25 with BRCA1/2 mutations were identified (BRCA1, 20.4%; BRCA2, 6.5%). On univariate analysis, er, pr, cytokeratin 5/6, egfr, and tnbc were found to be related to BRCA1 mutations, but on multivariate analysis, only tnbc was significantly associated with BRCA1 mutations. Among patients with early-onset breast cancer or with a family history of breast or ovarian cancer, BRCA1 mutations were significantly more prevalent in the tnbc group than in the non-tnbc group. CONCLUSIONS: In the present study, tnbc was the only independent predictor of BRCA1 mutation in patients at high risk of hereditary breast and ovarian cancers. Other histologic features of basal-like breast cancer did not improve the estimate of BRCA1 mutation risk.

9.
Breast Cancer Res Treat ; 136(1): 209-20, 2012 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-22965832

RESUMEN

Genome-wide association studies (GWAS) have identified various genetic susceptibility loci for breast cancer based mainly on European-ancestry populations. Differing linkage disequilibrium patterns exist between European and Asian populations, and thus GWAS-identified single nucleotide polymorphisms (SNPs) in one population may not be of significance in another population. In order to explore the role of breast cancer susceptibility variants in a Chinese population of Southern Chinese descent, we analyzed 22 SNPs for 1,191 breast cancer cases and 1,534 female controls. Associations between the SNPs and clinicopathological features were also investigated. In addition, we evaluated the combined effects of associated SNPs by constructing risk models. Eight SNPs were associated with an elevated breast cancer risk. Rs2046210/6q25.1 increased breast cancer risk via an additive model [per-allele odds ratio (OR) = 1.43, 95 % confidence interval (CI) = 1.26-1.62], and was associated with estrogen receptor (ER)-positive (per-allele OR = 1.39, 95 % CI = 1.20-1.61) and ER-negative (per-allele OR = 1.55, 95 % CI = 1.28-1.89) disease. Rs2046210 was also associated with stage 1, stage 2, and stage 3 disease, with per-allele ORs of 1.38 (1.14-1.68), 1.48 (1.25-1.74), and 1.58 (1.28-1.94), respectively. Four SNPs mapped to 10q26.13/FGFR2 were associated with increased breast cancer risk via an additive model with per-allelic risks (95 % CI) of 1.26 (1.12-1.43) at rs1219648, 1.22 (1.07-1.38) at rs2981582, 1.21 (1.07-1.36) at rs2981579, and 1.18 (1.04-1.35) at rs11200014. Variants of rs7696175/TLR1, TLR6, rs13281615/8q24, and rs16886165/MAP3K1 were also associated with increased breast cancer risk, with per-allele ORs (95 % CI) of 1.16 (1.00-1.34), 1.15 (1.02-1.29), and 1.15 (1.01-1.29), respectively. Five SNPs associated with breast cancer risk predominantly among ER-positive tumors (rs2981582/FGFR2, rs4415084/MRPS30, rs1219648/FGFR2, rs2981579/FGFR2, and rs11200014/FGFR2). Among our Chinese population, the risk of developing breast cancer increased by 90 % for those with a combination of 6 or more risk alleles, compared to patients with ≤3 risk alleles.


Asunto(s)
Neoplasias de la Mama , Estudios de Asociación Genética , Polimorfismo de Nucleótido Simple , Adulto , Alelos , Neoplasias de la Mama/genética , Neoplasias de la Mama/patología , China , Femenino , Sitios Genéticos , Predisposición Genética a la Enfermedad , Humanos , Desequilibrio de Ligamiento , Receptores de Estrógenos/genética , Receptores de Progesterona/genética , Factores de Riesgo
11.
Epidemiol Infect ; 140(7): 1161-72, 2012 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-22444943

RESUMEN

The purpose of this study was to examine global epidemiological trends in human norovirus (NoV) outbreaks by transmission route and setting, and describe relationships between these characteristics, viral attack rates, and the occurrence of genogroup I (GI) or genogroup II (GII) strains in outbreaks. We analysed data from 902 reverse transcriptase-polymerase chain reaction-confirmed, human NoV outbreaks abstracted from a systematic review of articles published from 1993 to 2011 and indexed under the terms 'norovirus' and 'outbreak'. Multivariate regression analyses demonstrated that foodservice and winter outbreaks were significantly associated with higher attack rates. Foodborne and waterborne outbreaks were associated with multiple strains (GI+GII). Waterborne outbreaks were significantly associated with GI strains, while healthcare-related and winter outbreaks were associated with GII strains. These results identify important trends for epidemic NoV detection, prevention, and control.


Asunto(s)
Infecciones por Caliciviridae/epidemiología , Infección Hospitalaria/epidemiología , Brotes de Enfermedades , Norovirus/clasificación , Número Básico de Reproducción , Infecciones por Caliciviridae/virología , Infección Hospitalaria/virología , Alimentos/virología , Gastroenteritis/epidemiología , Gastroenteritis/virología , Genotipo , Salud Global , Humanos , Norovirus/genética , Norovirus/aislamiento & purificación , Factores de Riesgo , Estaciones del Año , Microbiología del Agua
12.
Diabetologia ; 54(6): 1407-16, 2011 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-21340621

RESUMEN

AIMS/HYPOTHESIS: The role of Toll-like receptor 7 (TLR7), a sensor of viral and self RNA, in promoting autoimmune diabetes remains unclear. Our goal was to determine the effect of TLR7 stimulation on the priming and activation of diabetogenic CD8(+) T cells. METHODS: We explored the effects of CL097 (TLR7/8 agonist) and immunoregulatory sequence 661 (IRS661, TLR7 inhibitor) on bone marrow-derived dendritic cells (BMDCs), diabetogenic CD8(+) T cell function and autoimmune diabetes onset in NOD and 8.3 NOD T cell receptor transgenic mice (8.3 NOD mice). RESULTS: TLR7 stimulation of NOD BMDCs increased activation and production of proinflammatory cytokines. In vivo administration of CL097 activated T cells and dendritic cells and increased levels of proinflammatory cytokines and type 1/2 IFNs in NOD mice. In vivo antigen-specific cytotoxicity studies revealed enhanced cytotoxicity against islet-specific glucose-6-phosphatase catalytic subunit-related protein (IGRP, an islet autoantigen) peptide pulsed targets in NOD mice treated with CL097 plus CD40 agonist. This combination treatment accelerated the onset of autoimmune diabetes in 8.3 NOD mice. Likewise, topical treatment of NOD mice with a TLR7 agonist accelerated diabetes onset. Spontaneous disease in 8.3 NOD mice and accelerated disease in CL097+CD40 agonist-treated 8.3 NOD mice were delayed by IRS661 treatment, which is associated with inhibition of the endogenous upregulation of IFN-α levels within the pancreatic lymph nodes. CONCLUSIONS/INTERPRETATION: TLR7 stimulation accelerates the spontaneous onset of autoimmune diabetes in 8.3 NOD and NOD mice. Conversely, TLR7 inhibition prevents the early events associated with diabetogenesis.


Asunto(s)
Enfermedades Autoinmunes/inmunología , Enfermedades Autoinmunes/fisiopatología , Diabetes Mellitus/inmunología , Diabetes Mellitus/fisiopatología , Glicoproteínas de Membrana/fisiología , Receptor Toll-Like 7/fisiología , Animales , Enfermedades Autoinmunes/patología , Células de la Médula Ósea/citología , Linfocitos T CD4-Positivos/efectos de los fármacos , Linfocitos T CD4-Positivos/metabolismo , Linfocitos T CD4-Positivos/patología , Antígenos CD40/farmacología , Linfocitos T CD8-positivos/efectos de los fármacos , Linfocitos T CD8-positivos/metabolismo , Linfocitos T CD8-positivos/patología , Citocinas/metabolismo , Células Dendríticas/citología , Células Dendríticas/efectos de los fármacos , Células Dendríticas/metabolismo , Diabetes Mellitus/patología , Modelos Animales de Enfermedad , Imidazoles/farmacología , Interferón-alfa/metabolismo , Glicoproteínas de Membrana/agonistas , Glicoproteínas de Membrana/antagonistas & inhibidores , Glicoproteínas de Membrana/genética , Ratones , Ratones Endogámicos NOD , Ratones Transgénicos , Quinolinas/farmacología , Receptor Toll-Like 7/agonistas , Receptor Toll-Like 7/antagonistas & inhibidores , Receptor Toll-Like 7/genética
13.
Ann Oncol ; 22(11): 2431-2439, 2011 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-21382870

RESUMEN

BACKGROUND: Recently, the analysis of gastric and colorectal tumor specimens determined that 78-kiloDalton glucose-regulated protein (GRP78), an endoplasmic reticulum chaperone, up-regulation serves as an efficient mechanism protecting cells against apoptosis and can confer drug resistance. We tested whether functional polymorphisms within the GRP78 gene are related to clinical outcome in gastric and colorectal cancer (CRC) patients. PATIENTS AND METHODS: Blood samples of 234 stage II/III CRC patients at the University of Southern California (USC) and formalin-fixed paraffin-embedded tissues of 137 patients with localized gastric adenocarcinoma (GA) at USC and Memorial Sloan-Kettering Cancer Centers were obtained. GRP78 polymorphisms analyzed on germline DNA were correlated with clinical outcome using univariate and multivariate analyses. RESULTS: GA patients with the combined GRP78 rs391957 C/T and T/T genotype were at higher risk for tumor recurrence and death [hazard ratio (HR) 2.61; P < 0.001 and HR 3.17; P < 0.001, respectively], than those with C/C. These findings were subsequently tested in a CRC cohort where patients with the homozygous T/T genotype were at highest risk for tumor recurrence (HR 2.61; P = 0.015). The results remained significant after adjusting for clinicopathologic determinants. CONCLUSION: These data provide the first evidence that the GRP78 rs391957 polymorphism can predict clinical outcome in localized GA and locally advanced CRC patients.


Asunto(s)
Neoplasias Colorrectales/genética , Proteínas de Choque Térmico/genética , Neoplasias Gástricas/genética , Neoplasias Colorrectales/sangre , Neoplasias Colorrectales/patología , ADN de Neoplasias/sangre , ADN de Neoplasias/genética , Chaperón BiP del Retículo Endoplásmico , Femenino , Pruebas Genéticas , Haplotipos , Humanos , Masculino , Persona de Mediana Edad , Análisis Multivariante , Estadificación de Neoplasias , Polimorfismo de Nucleótido Simple , Pronóstico , Regiones Promotoras Genéticas , Neoplasias Gástricas/sangre , Neoplasias Gástricas/patología , Tasa de Supervivencia
14.
Curr Opin Cell Biol ; 4(2): 267-73, 1992 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-1599691

RESUMEN

The glucose-regulated protein family consists of a set of stress-inducible proteins localized in the endoplasmic reticulum. Since their discovery in 1977, significant advances in our understanding of their structure, function and regulation have been made. Recent findings concerning the physiological roles played by the glucose-regulated proteins, and their regulations at the transcriptional, post-transcriptional, translational and post-translational levels are summarized.


Asunto(s)
Proteínas HSP70 de Choque Térmico , Proteínas de Choque Térmico/fisiología , Proteínas de la Membrana/fisiología , Animales , Regulación de la Expresión Génica , Proteínas de Choque Térmico/genética , Humanos , Proteínas de la Membrana/genética , Biosíntesis de Proteínas , Procesamiento Proteico-Postraduccional , Transcripción Genética
15.
Curr Opin Cell Biol ; 3(2): 261-8, 1991 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-1883619

RESUMEN

It is proposed that the regulation of the pathways directing mammalian cell cycle progression involves several oncogenes. A summary of what is known about some of these regulatory oncogenes (fos, jun, myc, and Rb-1) and where they might function in the progression of a cell from G0 to G1 and G1 to S is presented. Data on two replication-dependent genes, those encoding histones and thymidine kinase, respectively, are also presented as models for describing transcriptional and post-transcriptional events at the G1-S border.


Asunto(s)
Ciclo Celular/genética , Oncogenes , Animales , Secuencia de Bases , ADN , Fase G1 , Regulación de la Expresión Génica , Histonas/genética , Humanos , Datos de Secuencia Molecular , Fase S , Timidina Quinasa/genética
16.
Nat Cell Biol ; 2(12): 863-70, 2000 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-11146649

RESUMEN

Presenilin 1 (PS1), a polytopic membrane protein, has a critical role in the trafficking and proteolysis of a selected set of transmembrane proteins. The vast majority of individuals affected with early onset familial Alzheimer's disease (FAD) carry missense mutations in PS1. Two studies have suggested that loss of PS1 function, or expression of FAD-linked PS1 variants, compromises the mammalian unfolded-protein response (UPR), and we sought to evaluate the potential role of PS1 in the mammalian UPR. Here we show that that neither the endoplasmic reticulum (ER) stress-induced accumulation of BiP and CHOP messenger RNA, nor the activation of ER stress kinases IRE1alpha and PERK, is compromised in cells lacking both PS1 and PS2 or in cells expressing FAD-linked PS1 variants. We also show that the levels of BiP are not significantly different in the brains of individuals with sporadic Alzheimer's disease or PS1-mediated FAD to levels in control brains. Our findings provide evidence that neither loss of PS1 and PS2 function, nor expression of PS1 variants, has a discernable impact on ER stress-mediated induction of the several established 'readouts' of the UPR pathway.


Asunto(s)
Proteínas Potenciadoras de Unión a CCAAT/genética , Proteínas Portadoras/genética , Proteínas de Choque Térmico , Proteínas de la Membrana/genética , Proteínas de la Membrana/metabolismo , Chaperonas Moleculares/genética , Factores de Transcripción/genética , Enfermedad de Alzheimer/genética , Enfermedad de Alzheimer/metabolismo , Animales , Línea Celular , Retículo Endoplásmico/metabolismo , Chaperón BiP del Retículo Endoplásmico , Variación Genética , Humanos , Ratones , Ratones Noqueados , Ratones Transgénicos , Presenilina-1 , Presenilina-2 , Desnaturalización Proteica , Pliegue de Proteína , Proteínas/química , Proteínas/metabolismo , ARN Mensajero/genética , ARN Mensajero/metabolismo , Factor de Transcripción CHOP , Regulación hacia Arriba
17.
Diabetologia ; 53(4): 741-8, 2010 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-20012858

RESUMEN

AIMS/HYPOTHESIS: Increased exposure to enteric microbes as a result of intestinal barrier disruption is thought to contribute to the development of several intestinal inflammatory diseases; however, it less clear whether such exposure modulates the development of extra-intestinal inflammatory and autoimmune diseases. The goal of this study was to examine the potential role of pathogenic enteric microbes and intestinal barrier dysfunction in the pathogenesis of type 1 diabetes. METHODS: Using NOD mice, we assessed: (1) intrinsic barrier function in mice at different ages by measuring serum levels of FITC-labelled dextran; and (2) the impact on insulitis development of infection by strains of an enteric bacterial pathogen (Citrobacter rodentium) either capable (wild-type) or incapable (lacking Escherichia coli secreted protein F virulence factor owing to deletion of the gene [DeltaespF]) of causing intestinal epithelial barrier disruption. RESULTS: Here we demonstrate that prediabetic (12-week-old) NOD mice display increased intestinal permeability compared with non-obese diabetes-resistant and C57BL/6 mice. We also found that young (4-week-old) NOD mice infected with wild-type C. rodentium exhibited accelerated development of insulitis in concert with infection-induced barrier disruption. In contrast, insulitis development was not altered in NOD mice infected with the non-barrier-disrupting DeltaespF strain. Moreover, C. rodentium-infected NOD mice demonstrated increased activation and proliferation of pancreatic-draining lymph node T cells, including diabetogenic CD8(+) T cells, compared with uninfected NOD mice. CONCLUSIONS/INTERPRETATION: This is the first demonstration that a loss of intestinal barrier integrity caused by an enteric bacterial pathogen results in the activation of diabetogenic CD8(+) T cells and modulates insulitis.


Asunto(s)
Infecciones Bacterianas/complicaciones , Animales , Infecciones Bacterianas/microbiología , Linfocitos T CD8-positivos/inmunología , Citrobacter rodentium/inmunología , Citrobacter rodentium/patogenicidad , Enterobacteriaceae/inmunología , Enterobacteriaceae/patogenicidad , Infecciones por Enterobacteriaceae/inmunología , Infecciones por Enterobacteriaceae/patología , Citometría de Flujo , Reordenamiento Génico , Hiperinsulinismo/microbiología , Inflamación/inmunología , Intestinos/microbiología , Intestinos/fisiología , Intestinos/fisiopatología , Activación de Linfocitos , Ratones , Ratones Endogámicos C57BL , Ratones Endogámicos NOD , Estado Prediabético/microbiología , Estado Prediabético/fisiopatología , Receptores de Antígenos de Linfocitos T/genética , Especificidad de la Especie
18.
Cell Death Differ ; 15(9): 1460-71, 2008 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-18551133

RESUMEN

In mammalian cells, endoplasmic reticulum (ER) stress has recently been shown to induce autophagy and the induction requires the unfolded protein response (UPR) signaling pathways. However, little is known whether autophagy regulates UPR pathways and how specific UPR targets might control autophagy. Here, we demonstrated that although ER stress-induced autophagy was suppressed by class III phosphatidylinositol-3'-kinase (PI3KC3) inhibitor 3-methyladenine (3-MA), wortmannin and knockdown of Beclin1 using small interfering RNA (siRNA), only 3-MA suppressed UPR activation. We discovered that the UPR regulator and ER chaperone GRP78/BiP is required for stress-induced autophagy. In cells in which GRP78 expression was knocked down by siRNA, despite spontaneous activation of UPR pathways and LC3 conversion, autophagosome formation induced by ER stress as well as by nutrition starvation was inhibited. GRP78 knockdown did not disrupt PI3KC3-Beclin1 association. However, electron microscopic analysis of the intracellular organelle structure reveals that the ER, a putative membrane source for generating autophagosomal double membrane, was massively expanded and disorganized in cells in which GRP78 was knocked down. ER expansion is known to be dependent on the UPR transcription factor XBP-1. Simultaneous knockdown of GRP78 and XBP-1 recovered normal levels of stress-induced autophagosome formation. Thus, these studies uncover 3-MA as an inhibitor of UPR activation and establish GRP78 as a novel obligatory component of autophagy in mammalian cells.


Asunto(s)
Autofagia , Retículo Endoplásmico/metabolismo , Proteínas de Choque Térmico/fisiología , Chaperonas Moleculares/fisiología , Adenina/análogos & derivados , Adenina/farmacología , Proteínas Reguladoras de la Apoptosis/metabolismo , Proteínas Reguladoras de la Apoptosis/fisiología , Autofagia/efectos de los fármacos , Beclina-1 , Línea Celular , Retículo Endoplásmico/ultraestructura , Chaperón BiP del Retículo Endoplásmico , Proteínas de Choque Térmico/antagonistas & inhibidores , Proteínas de Choque Térmico/genética , Humanos , Proteínas de la Membrana/metabolismo , Proteínas de la Membrana/fisiología , Chaperonas Moleculares/antagonistas & inhibidores , Chaperonas Moleculares/genética , Fagosomas/ultraestructura , Fosfatidilinositol 3-Quinasas/metabolismo , Pliegue de Proteína , Interferencia de ARN , Transducción de Señal
19.
J Cell Biol ; 92(3): 629-33, 1982 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-7085753

RESUMEN

K12 is a temperature-sensitive (ts) mutant cell line derived from Chinese hamster fibroblasts. When incubated at the nonpermissive temperature, K12 cells exhibit the following properties: (a) the cells cannot initiate DNA synthesis;o (b) the synthesis of cytosol thymidine kinase is suppressed; and (c) the synthesis of three cellular proteins of molecular weights 94, 78, and 58 kdaltons is greatly enhanced. Here we characterize a spontaneous revertant clone, R12, derived from the K12 cells. We selected the revertant clone for its ability to grow at the nonpermissive temperature. Our results indicate that all the traits which constitute the K12 mutant phenotype are simultaneously reverted to the wild type in the revertant cell line, suggesting that the ts mutation of the K12 cells is of regulatory nature and exerts multiple effects on the expressed phenotypes.


Asunto(s)
Interfase , Mutación , Animales , Línea Celular , Cricetinae , Citosol/enzimología , ADN/biosíntesis , Fibroblastos/citología , Cariotipificación , Biosíntesis de Proteínas , Temperatura , Timidina Quinasa
20.
J Cell Biol ; 103(6 Pt 1): 2145-52, 1986 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-3097027

RESUMEN

The calcium ionophore A23187 can reversibly induce the expression of two glucose-regulated genes, p3C5 and p4A3. This induction requires a continuous presence of the ionophore for over 2 h. Although extracellular Ca2+ is important for the optimal effect of A23187, it is not necessary for the induction, since a similar response with a lower magnitude can be triggered in cells cultured in low Ca2+ medium buffered with EGTA. Both the basal and induced levels of p3C5 and p4A3 transcripts can be modulated by the calmodulin antagonist W-7, indicating the involvement of Ca2+/calmodulin-associated pathways. In addition, the sensitivity of the A23187 induction to cycloheximide suggests that the induction process is dependent on de novo protein synthesis.


Asunto(s)
Calcimicina/farmacología , Genes Reguladores/efectos de los fármacos , Genes/efectos de los fármacos , Proteínas HSP70 de Choque Térmico , Proteínas de la Membrana/genética , Animales , Calcio/farmacología , Línea Celular , Cricetinae , Proteínas de la Membrana/biosíntesis , Hibridación de Ácido Nucleico , Plásmidos , Transcripción Genética/efectos de los fármacos
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