RESUMEN
BACKGROUND: The mechanism that estrogen (E(2)) increases the number of endothelial progenitor cells (EPC) is largely unknown. Here we used E(2)-conjugated bovine serum albumin (E(2)-BSA, membrane impermeable) to investigate whether the membrane estrogen receptor (mER) and its related protein caveolin-1 (CAV-1) are involved in these processes. METHODS AND RESULTS: E(2)-BSA promoted [(3)H]-thymidine incorporation of EPC through increasing CAV-1 expression via mER (ERα, but not ERß or GPR30). Both cholesterol depletion and CAV-1 knockdown with use of CAV-1 siRNA significantly attenuated E(2)-BSA-induced [(3)H]-thymidine incorporation. Western blot showed that E(2)-BSA increased membrane CAV-1 protein expression 12h after treatment, whereas mRNA levels of CAV-1 were augmented until 24h after E(2)-BSA treatment. Furthermore, pre-incubated EPC with ICI 182780 (a specific ER antagonist), LY 294002 (a selective PI(3)K inhibitor) or PD 98059 (a specific ERK1/2 inhibitor) before E(2)-BSA inhibited the late-stage effect of E(2)-BSA (≥24 h) on up-regulation of CAV-1 mRNA and protein expression. Pulse chase results demonstrated that E(2)-BSA inhibited lysosome-mediated degradation of CAV-1 protein at the early stage (≤12 h), and then resulted in the increased CAV-1 protein. CONCLUSION: In the present work we demonstrated that E(2)-BSA promotes EPC proliferation through mER (ERα) in CAV-1-dependent manner: prolonging the stability of CAV-1 protein through quick inhibition of the lysosomal degradation pathway at the early stage (≤12 h) and up-regulating CAV-1 at transcription levels through PI(3)K/ERK1/2 signaling pathway at the late stage (≥24 h). These data indicated that a there is a novel mechanism of E(2)-BSA in the regulation of EPC proliferation through CAV-1.
Asunto(s)
Caveolina 1/fisiología , Proliferación Celular , Células Endoteliales/citología , Estradiol/fisiología , Lisosomas/fisiología , Sistema de Señalización de MAP Quinasas/fisiología , Fosfatidilinositol 3-Quinasas/fisiología , Albúmina Sérica Bovina/fisiología , Animales , Femenino , Ratas , Ratas Sprague-Dawley , Células MadreRESUMEN
OBJECTIVE: Prehypertension is a new category designated by the Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure (JNC7) in 2003. Managing prehypertension with nonpharmacological intervention is possibly beneficial to the prevention of hypertension. In this study, we observed the effect of slow abdominal breathing combined with electromyographic (EMG) biofeedback training on blood pressure (BP) in prehypertensives and assessed the changes of heart rate variability (HRV) in order to find an optional intervention to prevent hypertension and acquire some experimental data to clarify the underlying neural mechanism. METHODS: Twenty-two (22) postmenopausal women with prehypertension were randomly assigned to either the experiment group or the control group. The experiment group performed 10 sessions of slow abdominal breathing (six cycles/min) combined with frontal electromyographic (EMG) biofeedback training and daily home practice, while the control group only performed slow abdominal breathing and daily home practice. BP and HRV (including R-R interval and standard deviation of the normal-normal intervals [SDNN]) were measured. RESULTS: Participants with prehypertension could lower their systolic blood pressure (SBP) 8.4 mm Hg (p < 0.001) and diastolic blood pressure (DBP) 3.9 mm Hg (p < 0.05) using slow abdominal breathing combined with EMG biofeedback. The slow abdominal breathing also significantly decreased the SBP 4.3 mm Hg (p < 0.05), while it had no effect on the DBP (p > 0.05). Repeated-measures analyses showed that the biofeedback group + abdominal respiratory group (AB+BF) training was more effective in lowering the BP than the slow breathing (p < 0.05). Compared with the control group, the R-R interval increased significantly during the training in the AB+BF group (p < 0.05). The SDNN increased remarkably in both groups during the training (p < 0.05). CONCLUSIONS: Slow abdominal breathing combined with EMG biofeedback is an effective intervention to manage prehypertension. The possible mechanism is that slow abdominal breathing combined with EMG biofeedback could reduce sympathetic activity and meanwhile could enhance vagal activity.
Asunto(s)
Biorretroalimentación Psicológica/métodos , Presión Sanguínea , Ejercicios Respiratorios , Frecuencia Cardíaca/fisiología , Prehipertensión/terapia , Respiración , Terapia Combinada , Femenino , Humanos , Persona de Mediana Edad , PosmenopausiaRESUMEN
OBJECTIVE: Growing evidence indicates that estrogen's non-genomic effects play important roles in cellular functions and backs up the hypothesis of the existence of a membrane estrogen receptor (mER) in a number of cell types, but little is known about the complementary effects between traditional genomic and novel non-genomic effects of estrogen. The aim of the present study was to explore the non-genomic activation of ERK1/2 mitogen-activated protein kinase (MAPK) by 17beta-estradiol (E(2)) through mER and its role in cell proliferation. METHODS: On cultured bovine artery endothelial cells (BAECs) we used the [(3)H]thymidine incorporation assay to evaluate the influence of E(2) on cell proliferation and fluorescence microscopy to show the presence of mER on the cell membrane. Scatchard analysis was performed to identify and characterize the mER on a purified membrane fraction of BAECs. RESULTS: E(2) upregulated cyclin D1 protein expression and enhanced cell proliferation. Inhibition of the MAPK cascade with PD98059 or of G protein with pertussis toxin (PTX) completely abolished the above effects, while the estrogen receptor antagonist tamoxifen attenuated E(2)-dependent upregulation of cyclin D1 and cell proliferation. Accordingly, E(2) rapidly led to ERK1/ERK2 activation, which was prevented by tamoxifen or PTX and was entirely reproduced by membrane-impermeable estradiol-bovine serum albumin conjugate (E(2)coBSA). Immunofluorescent staining with E(2)coBSA-fluorescein isothiocyanate resulted in a punctuate staining pattern of the plasma membrane and Scatchard analysis of the E(2)-binding protein in a purified membrane fraction of BAECs showed that E(2) binds to the membrane fraction with a dissociation constant of 0.2394 nmol/l. CONCLUSION: Our findings showed that E(2) induces cell proliferation through upregulation of cyclin D1 via non-genomic activation of the ERK1/ERK2 pathway mediated by mER and G protein.
Asunto(s)
Proliferación Celular , Ciclina D1/metabolismo , Células Endoteliales/enzimología , Estradiol/fisiología , Receptores de Estrógenos/fisiología , Animales , Arterias/citología , Bovinos , Células Cultivadas , Proteínas de Unión al GTP/fisiología , Proteína Quinasa 1 Activada por Mitógenos/metabolismo , Proteína Quinasa 3 Activada por Mitógenos/metabolismo , Transducción de Señal/fisiología , Regulación hacia ArribaRESUMEN
BACKGROUND: Estrogen might play an important role in type 2 diabetes mellitus pathogenesis. A number of polymorphisms have been reported in the estrogen receptor alpha (ERalpha) gene (also named ESR1), including the XbaI and PvuII restriction enzyme polymorphisms of ESR1, which may be involved in disease pathogenesis. The aim of this study was to determine whether ERX gene polymorphisms are associated with type 2 diabetes mellitus and serum lipid level. METHODS: Two hundred and ninety-nine patients with type 2 diabetes mellitus were compared with three hundred and forty-one health controls of Guangzhou in China, both were male and postmenopausal female residents at 51 - 70 years. ESR1 genotyping was performed using polymerase chain reaction (PCR) and PvuII and XbaI restriction fragment length polymorphism (PCR-RFLP) analysis. RESULTS: ESR1 allelic frequencies of P, p and X, x alleles were 0.408, 0.592; 0.360, 0.640 in the type 2 diabetes mellitus group and 0.318, 0.682; 0.328, 0.672 in the control group, respectively. In case-control study, there was significant difference in PvuII, but not XbaI, allele frequency between the type 2 diabetes mellitus and control groups (P = 0.001 and P = 0.122). When the group was separated into men and women, the difference was significant in women (P < 0.001) but not in men (P = 0.854) with the PvuII genotype, and the effect of PvuII variant on the development of type 2 diabetes mellitus was improved with aging. In addition, PvuII genotype was associated with blood glucose [fasting blood glucose (FBG), postprandial blood glucose (PBG)] and serum lipid [total cholesterol (TC) and low density lipoprotein (LDL)-c] concentration in healthy women. CONCLUSIONS: PvuII polymorphism of ESR1 increases susceptibility to type 2 diabetes mellitus in Chinese Guangzhou women. ESR1 variants may also impact serum lipid metabolism, which might provide a mechanism connecting ESR1 to type 2 diabetes.
Asunto(s)
Diabetes Mellitus Tipo 2/genética , Receptor alfa de Estrógeno/genética , Lípidos/sangre , Polimorfismo Genético , Anciano , Glucemia/análisis , LDL-Colesterol/sangre , Diabetes Mellitus Tipo 2/sangre , Femenino , Genotipo , Humanos , Modelos Logísticos , Persona de Mediana EdadRESUMEN
The present study investigated the effects of raloxifene, a second generation selective estrogen receptor modulator (SERM), plus 17-betaE2 on aortic atherosclerosis and mammary gland hyperplasia in ovariectomized, cholesterol-fed rabbits. Following 10 weeks of raloxifene, 17-betaE2, or raloxifene plus 17-betaE2 administration, serum total cholesterol, triglyceride, low density lipoprotein were significantly decreased in the drug groups compared to the placebo group. Consistent with serum lipid results, the total lesion area for each aorta of the drug groups decreased significantly as compared to the placebo group. HE staining of aorta paraffin section showed that in the drug groups the endothelial monolayer was almost continuous. While in mammary gland, HE staining of paraffin sections indicated the hyperplasia of epithelial cells (in 17-betaE2 group) was obviously inhibited in raloxifene plus 17-betaE2 group. In cultured vascular smooth muscle cell (VSMC), the results of MTT and [3H]TdR incorporation showed that the drug groups could inhibit AngII-induced proliferation of VSMC. Western blotting proved that raloxifene plus 17-betaE2 inhibited the expression of phosphorylated ERK protein, similar to 17-betaE2 but different from raloxifene. This effect was inhibited by PD98059 (inhibitor of MAPK) or ICI182780 (ER antagonist). In conclusion, this study suggests that SERM raloxifene plus 17-betaE2 improves the lipid metabolism and relieves the aorta changes of female experimental atherosclerosis rabbits, which are partly implemented by the inhibition of VSMC growth through ERK cascade. The hyperplasia of mammary gland epithelial cells could be significantly inhibited by raloxifene plus 17-betaE2.
Asunto(s)
Aorta/efectos de los fármacos , Aterosclerosis/tratamiento farmacológico , Estradiol/farmacología , Glándulas Mamarias Animales/patología , Clorhidrato de Raloxifeno/farmacología , Moduladores Selectivos de los Receptores de Estrógeno/farmacología , Animales , Aterosclerosis/patología , Western Blotting , Interacciones Farmacológicas , Estradiol/uso terapéutico , Quinasas MAP Reguladas por Señal Extracelular/efectos de los fármacos , Femenino , Hiperplasia/tratamiento farmacológico , Lípidos/sangre , Glándulas Mamarias Animales/efectos de los fármacos , Músculo Liso Vascular/efectos de los fármacos , Conejos , Moduladores Selectivos de los Receptores de Estrógeno/uso terapéutico , Transducción de Señal/efectos de los fármacos , Sales de Tetrazolio , Tiazoles , TimidinaRESUMEN
The aim of the present study was to investigate the role of caveolin-1 in the inhibition of endothelin-1 induced proliferation of vascular smooth muscle cells (VSMCs) by 17beta-estradiol. In the cultured rat thoracic aortic VSMCs, proliferation of VSMCs was determined by using [(3)H]-thymidine incorporation and the expression of caveolin-1 protein was measured by immunofluorescence assays and Western blotting. The measurement demonstate VSMCs exposed to various concentrations of endothelin-1 (1-100 nmol/L) for 24 h induced an increase in [(3)H]-thymidine incorporation. Pretreament with various concentrations of 17beta-estradiol (0.1-10 nmol/L) for 24 h inhibited the proliferation effect of endothelin-1. Immunofluorescence assays showed that after 24 h treatment of VSMCs with endothelin-1 (100 nmol/L), the expression of caveolin-1 in VSMCs was significantly increased, whereas pretreament with 17beta-estradiol (10 nmol/L) for 24 h inhibited the effect. Western blotting results further proved that endothelin-1 inhibited and 17beta-estradiol increased the expression of caveolin-1 in VSMCs. These results demonstrate that 17beta-estradiol inhibits the VSMCs proliferation induced by endothelin-1, and that the effect of estradiol is probably mediated by caveolin-1.
Asunto(s)
Caveolina 1/fisiología , Endotelina-1/fisiología , Estradiol/farmacología , Músculo Liso Vascular/citología , Animales , Aorta Torácica/citología , División Celular , Células Cultivadas , Endotelina-1/antagonistas & inhibidores , Ratas , Ratas Sprague-DawleyRESUMEN
OBJECTIVE: To provide a test platform for experimental verification of environmental control and life support system (ECLSS) of manned spacecraft on the ground. METHOD: According to characters of ECLSS ground simulation test, simulation of human body metabolism was divided into different units, and a ground metabolic simulator was designed. RESULT: The ground metabolic simulator accurately simulated human body metabolic oxygen consumption, carbon dioxide production, water and heat productions in the sealed module. CONCLUSION: The physical method for simulating human body metabolism is feasible and has the advantages of high precision and easiness of control. It can be used for verifying and appraising the function of ECLSS.