共查询到20条相似文献,搜索用时 31 毫秒
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Zhang FL Shen GM Liu XL Wang F Zhao YZ Zhang JW 《Journal of cellular and molecular medicine》2012,16(8):1889-1899
Hypoxia-inducible factor promotes erythropoiesis through coordinated cell type-specific hypoxia responses. GATA1 is essential to normal erythropoiesis and plays a crucial role in erythroid differentiation. In this study, we show that hypoxia-induced GATA1 expression is mediated by HIF1 in erythroid cells. Under hypoxic conditions, significantly increased GATA1 mRNA and protein levels were detected in K562 cells and erythroid induction cultures of CD34(+) haematopoietic stem/progenitor cells. Enforced HIF1α expression increased GATA1 expression, while HIF1α knockdown by RNA interference decreased GATA1 expression. In silico analysis revealed one potential hypoxia response element (HRE). The results from reporter gene and mutation analysis suggested that this element is necessary for hypoxic response. Chromatin immunoprecipitation (ChIP)-PCR showed that the putative HRE was recognized and bound by HIF1 in vivo. These results demonstrate that the up-regulation of GATA1 during hypoxia is directly mediated by HIF1.The mRNA expression of some erythroid differentiation markers was increased under hypoxic conditions, but decreased with RNA interference of HIF1α or GATA1. Flow cytometry analysis also indicated that hypoxia, desferrioxamine or CoCl(2) induced expression of erythroid surface markers CD71 and CD235a, while expression repression of HIF1α or GATA1 by RNA interference led to a decreased expression of CD235a. These results suggested that HIF1-mediated GATA1 up-regulation promotes erythropoiesis in order to satisfy the needs of an organism under hypoxic conditions. 相似文献
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范新明周鸣彭建强郭莹 《现代生物医学进展》2011,11(20):3994-3996
缺氧诱导因子(HIF)是参与缺氧转录反应调控的转录调控因子,HIF的活化在缺氧时细胞中保护起重要作用,HIF及HIF依赖的基因如诱导型一氧化氮合酶(iNOS)、血红素氧合酶(HO-1)的激活可减轻心脏的缺血-再灌注损伤,HIF调节的基因表达可能介导了缺血预处理和缺血后处理的保护作用。本文对HIF在心肌缺血再灌注损伤中的保护作用予以综述。 相似文献
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Hundreds of genes can be regulated by hypoxia-inducible factor 1 (HIF1) under hypoxia. Here we demonstrated a HIF1-mediated induction of protein phosphatase 1, regulatory subunit 3C gene (PPP1R3C) in human MCF7 cells under hypoxia. By mutation analysis we confirmed the presence of a functional hypoxia response element that is located 229 bp upstream from the PPP1R3C gene. PPP1R3C induction correlates with a significant glycogen accumulation in MCF7 cells under hypoxia. Knockdown of either HIF1α or PPP1R3C attenuated hypoxia-induced glycogen accumulation significantly. Knockdown of HIF2α reduced hypoxia-induced glycogen accumulation slightly (but not significantly). Our results demonstrated that HIF1 promotes glycogen accumulation through regulating PPP1R3C expression under hypoxia, which revealed a novel metabolic adaptation of cells to hypoxia. 相似文献
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Hypoxia up-regulates hypoxia-inducible factor-1alpha transcription by involving phosphatidylinositol 3-kinase and nuclear factor kappaB in pulmonary artery smooth muscle cells 总被引:7,自引:0,他引:7 下载免费PDF全文
Belaiba RS Bonello S Zähringer C Schmidt S Hess J Kietzmann T Görlach A 《Molecular biology of the cell》2007,18(12):4691-4697
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Hiu T Nakagawa S Hayashi K Kitagawa N Tsutsumi K Kawakubo J Honda M Suyama K Nagata I Niwa M 《Cellular and molecular neurobiology》2008,28(8):1139-1146
Hemorrhagic transformation is a major complication associated with tissue plasminogen activator (tPA) therapy for ischemic
stroke. We studied the effect of tPA on the blood–brain barrier (BBB) function with our in vitro monolayer model generated
using rat brain microvascular endothelial cells subjected either to normoxia or to hypoxia/reoxygenation (H/R) with or without
the administration of tPA. The barrier function was evaluated by the transendothelial electrical resistance (TEER), the permeability
of sodium fluorescein and Evans’ blue-albumin (EBA), and the uptake of lucifer yellow (LY). The permeability of sodium fluorescein
and EBA was used as an index of paracellular and transcellular transport, respectively. The administration of tPA increased
the permeability of EBA and the uptake of LY under normoxia. It enhanced the increase in the permeability of both sodium fluorescein
and EBA, the decrease in the TEER, and the disruption in the expression of ZO-1 under H/R conditions. Administration of tPA
could cause an increase in the transcellular transport under normoxia, and both the transcellular and paracellular transport
of the BBB under H/R conditions in vitro. Even in humans, tPA may lead to an opening of the BBB under non-ischemic conditions
and have an additional effect on the ischemia-induced BBB disruption. 相似文献
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Gunda Millonig Stephan Hegedüsch Laren Becker Helmut-Karl Seitz Detlef Schuppan Sebastian Mueller 《Free radical biology & medicine》2009,46(2):182-191
HIF1 (hypoxia-inducible factor 1α) is considered a central oxygen-threshold sensor in mammalian cells. In the presence of oxygen, HIF1 is marked by prolyl hydroxylases (PHDs) at the oxygen-dependent degradation (ODD) domain for ubiquitination followed by rapid proteasomal degradation. However, the actual mechanisms of oxygen sensing by HIF1 are still controversial. Thus, HIF1 expression correlates poorly with tissue oxygen levels, and PHDs are themselves target genes of HIF1 considered to readjust to new oxygen thresholds. In contrast to hypoxia chambers, we here establish an enzymatic model that allows both the rapid induction of stable hypoxia and independent control of H2O2. Rapid enzymatic hypoxia only transiently induced HIF1 in various cell types and the HIF1 was completely degraded within 8–12 h despite sustained hypoxia. HIF1 degradation under sustained hypoxia could be blocked by a competitive ODD–GFP construct and PHD siRNA, but also by cobalt chloride and micromolar H2O2 levels. Concomitant induction of PHDs further confirmed their role in degrading HIF1 under enzymatic hypoxia. The rapid and complete degradation of HIF1 under enzymatic hypoxia suggests that, in addition to hypoxia sensing, the HIF1/PHD loop may rather compensate for fluctuations of tissue oxygen staying tuned to other, e.g., metabolic, signals. In addition to hypoxia chambers, enzymatic hypoxia provides a valuable tool for independently studying the regulatory functions of hypoxia and oxidative stress in vitro. 相似文献
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Ischemia/reperfusion induces the recruitment of leukocytes from whole blood under flow conditions 总被引:7,自引:0,他引:7
Cassie S Masterson MF Polukoshko A Viskovic MM Tibbles LA 《Free radical biology & medicine》2004,36(9):1102-1111
Ischemia/reperfusion (I/R) occurs in a number of pathological conditions, including myocardial infarction, stroke, and organ transplantation. During the reperfusion phase, leukocytes are recruited into affected tissues, where they can cause tissue damage and organ failure. Various in vitro models have been developed to study the role of adhesion molecules in I/R-mediated leukocyte recruitment. These models traditionally use isolated leukocytes and static conditions and, therefore, may not recapitulate the in vivo situation. We developed two novel in vitro models of I/R-mediated leukocyte recruitment in which leukocyte recruitment was examined using whole blood under shear conditions. Chemical treatments were used to mimic I/R in the first model, while sequential exposure to hypoxia/reoxygenation (H/R) was used to mimic I/R in the second model. We found that leukocytes were recruited from whole blood under shear conditions to endothelial cells treated with chemically induced I/R or H/R. In both models, mRNA for intercellular adhesion molecule 1 (ICAM-1), vascular cell adhesion molecule 1 (VCAM-1), and E-selectin was upregulated. The role of adhesion molecules in leukocyte recruitment differed slightly between the two models, with E-selectin and VCAM-1 playing approximately equal roles in leukocyte recruitment in the chemically induced I/R model and VCAM-1 being a central mediator of leukocyte recruitment in the H/R model. 相似文献
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Choi JY Kim BM Kim YJ Woo HD Chung HW 《Biochemical and biophysical research communications》2007,352(2):366-371
Reactive oxygen species (ROS) generated after exposure to hypoxia and reoxygenation (H/R) play a pivotal role in the stimulation of cell death. In this study, we explored H/R-induced cytotoxicity in human lymphocytes. Compared to cells under normoxic conditions, H/R-treated cells exhibited significantly decreased viability and increased DNA breakage. Western blotting analysis demonstrated that H/R-induced the accumulation of p53 and p63 proteins. H/R also led to the activation of caspase-3 and -9, accompanied by the cleavage of PARP (poly(ADP-ribose)polymerase). Because apoptosis is usually accompanied by ROS generation and collapse of the mitochondrial membrane potential (MMP, Deltapsi(m)), we examined ROS and MMP levels in H/R-treated lymphocytes. Cells subjected to H/R exhibited significantly increased ROS and decreased MMP, compared with normoxic cells. Taken together, these results indicate that H/R treatment of human lymphocytes induces rapid ROS generation and MMP collapse, which triggers apoptosis. 相似文献
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Tumor necrosis factor (TNF) alpha is a critical mediator of inflammation; however, TNFalpha is rarely released alone and the "cross-talk" between different classes of inflammatory mediators is largely unexplored. Thromboxane A(2) (TXA(2)) is released during I/R injury and exerts its effects via a G protein-linked receptor (TP). In this study, we found that TXA(2) mimetics stimulate leukocyte adhesion molecule (LAM) expression on endothelium via TPbeta. The potential interaction between TXA(2) and TNFalpha in altering endothelial survival and LAM expression was examined. IBOP, a TXA(2) mimetic, attenuated TNFalpha-induced LAM expression in vitro, in a concentration-dependent manner, by preventing TNFalpha-enhanced gene expression, and also reduced TNFalpha-induced leukocyte adhesion to endothelium both in vitro and in vivo. IBOP abrogated TNFalpha-induced NFkappaB activation in endothelial cells, as determined by reduced IkappaB phosphorylation and NFkappaB nuclear translocation, by inhibiting the assembly of signaling intermediates with the intracellular domain of TNF receptors 1 and 2 in response to TNFalpha. This inhibition resulted from the Galpha(q)-mediated enhancement of STAT1 activation and was reversed by anti-STAT1 antisense oligonucleotides. TNFalpha-mediated TNFR1-FADD association and caspase 8 activation were not inhibited by IBOP co-stimulation, however, resulting in a 2.6-fold increase in endothelial cell apoptosis. By stimulating the vessel wall and inducing endothelial cell apoptosis, TXA(2), in combination with TNFalpha, may hamper the angiogenic response during inflammation or ischemia, thus reducing revascularization and tissue viability. 相似文献
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Weirong Fang Peng Lv Xiaohan Geng Erxin Shang Qichuan Yang Lan Sha Yunman Li 《Neurochemistry international》2013
Background
Blood brain barrier (BBB) dysfunction is a common facet of cerebral ischemia, and the alteration of drug transporter, P-glycoprotein (P-gp), has been documented.Aims
This study explores influence of damaged BBB and elevated P-gp on cerebral verapamil penetration after ischemia both in vivo and in vitro.Methods
Middle cerebral artery occlusion (MCAO) induced ischemia/reperfusion (I/R) of rats, and Na2S2O4 induced hypoxia/reoxygenation (H/R) damage of rat brain mirovessel endothelial cells (RBMECs) respectively, served as BBB breakdown model in vivo and in vitro. Evans-Blue (EB) extravagation and 125I-albumin were used to quantify BBB dysfunction; UPLC–MS/MS analytical method was performed to determine accurately the concentration of verapamil in brain tissue and cell. Flow cytometry, immunohistochemistry and western blotting were applied to evaluate transport function and protein expression of P-gp.Results
Overexpressed ICAM-1 and MMP-9 mediated BBB dysfunction after ischemia, which induced EB leakage and 125I-albumin uptake increase. Enhanced accumulation of verapamil in brain tissue, but intracellular concentration reduced evidently after H/R injury. Transcellular transportation of verapamil elevated when P-gp function or expression was inhibited after H/R injury.Conclusion
These data indicated that BBB penetration of verapamil under ischemia condition was not only depending on BBB breakdown, but also regulated by P-gp. 相似文献18.
Knuefermann P Chen P Misra A Shi SP Abdellatif M Sivasubramanian N 《The Journal of biological chemistry》2002,277(26):23888-23897
Myotrophin/V-1 is a cytosolic protein found at elevated levels in failing human hearts and in postnatal cerebellum. We have previously shown that it disrupts nuclear factor of kappaB (NFkappaB)-DNA complexes in vitro. In this study, we demonstrated that in HeLa cells native myotrophin/V-1 is predominantly present in the cytoplasm and translocates to the nucleus during sustained NFkappaB activation. Three-dimensional alignment studies indicate that myotrophin/V-1 resembles a truncated IkappaBalpha without the signal response domain (SRD) and PEST domains. Co-immunoprecipitation studies reveal that myotrophin/V-1 interacts with NFkappaB proteins in vitro; however, it remains physically associated only with p65 and c-Rel proteins in vivo during NFkappaB activation. In vitro studies indicate that myotrophin/V-1 can promote the formation of p50-p50 homodimers from monomeric p50 proteins and can convert the preformed p50-p65 heterodimers into p50-p50 and p65-p65 homodimers. Furthermore, adenovirus-mediated overexpression of myotrophin/V-1 resulted in elevated levels of both p50-p50 and p65-p65 homodimers exceeding the levels of p50-p65 heterodimers compared with Adbetagal-infected cells, where the levels of p50-p65 heterodimers exceeded the levels of p50-p50 and p65-p65 homodimers. Thus, overexpression of myotrophin/V-1 during NFkappaB activation resulted in a qualitative shift by quantitatively reducing the level of transactivating heterodimers while elevating the levels of repressive p50-p50 homodimers. Correspondingly, overexpression of myotrophin/V-1 resulted in significantly reduced kappaB-luciferase reporter activity. Because myotrophin/V-1 is found at elevated levels during NFkappaB activation in postnatal cerebellum and in failing human hearts, this study cumulatively suggests that myotrophin/V-1 is a regulatory protein for modulating the levels of activated NFkappaB dimers during this period. 相似文献
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Manuela Indelicato Bruna Pucci Luana Schito Valentina Reali Michele Aventaggiato Maria C. Mazzarino Franca Stivala Massimo Fini Matteo A. Russo Marco Tafani 《Journal of cellular physiology》2010,223(2):359-368
Survival strategies adopted by tumor cells in response to a hypoxic stress include activation of hypoxia‐inducible factor 1 (HIF‐1) and autophagy. However, the importance and the function of each molecular response is not well defined. In the present study, we investigated invasiveness, migration, matrix metalloproteinases (MMPs) activity, and cell survival of MDA‐MB‐231 cells under normoxia, hypoxia, and hypoxia/reoxygenation (H/R). Moreover, to assess the importance of hypoxia and autophagy on the parameters studied, cells were either left untreated or treated with Chetomin (a selective inhibitor of HIF‐1α) or trifluoperazine (TFP, an activator of autophagy). We found that hypoxia and H/R stimulated invasiveness and migration of MDA‐MB‐231 cells with an increased MMP‐2 activity. Chetomin and TFP differently regulated the cellular behavior under the oxygenation conditions studied. In fact, Chetomin was most effective in inhibiting cell invasion, MMPs activity, and cell survival under hypoxia but not normoxia or H/R. By contrast, TFP inhibition of cell invasion, migration, and cell survival was independent from oxygenation conditions. TFP‐induced autophagy was inhibited by light chain protein 3 (LC3) silencing or 3‐methyladenine (3MA) treatment. In fact, LC3‐silenced cells were able to invade in the presence of TFP without any GATE16 processing and p62 degradation. Immunofluorescence assay showed that LC3 silencing inhibited TFP‐induced autophagosome formation. However, we also showed that both TPF treatment and LC3 silencing caused cytoskeleton impairments suggesting a possible interaction between LC3 and cytoskeleton components. In conclusion, our study shows that hypoxia and autophagy by acting on common (HIF‐1α) or separate (MMPs, cytoskeleton) targets differently regulate cell invasion, MMPs activity, and survival. J. Cell. Physiol. 223: 359–368, 2010. © 2010 Wiley‐Liss, Inc. 相似文献