Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0022116 (ischemia)
 91,303 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The transcription factor HIF-1alpha has been identified as a key regulator in the cellular and systemic response to hypoxia. Because hypoxia is frequently associated with acidosis, like in ischemia or tumour growth, we studied the impact of acidosis on the expression of the HIF-1alpha and HIF-2alpha proteins and that of the three HIF target genes carbonic anhydrase-9 (CA-9), glucose transporter-1 (Glut-1) and erythropoietin (EPO). Since the HIF-prolyl hydroxylases (PHD) modulate cellular HIF-alpha protein levels we also investigated changes in PHD mRNA expression under hypoxia and acidosis. HIF-1alpha immunoblots revealed, depending on the cell line investigated, a moderate induction of HIF-alpha protein levels by acidosis in normoxia (Hep3B cells) or hypoxia (HeLa cells). Concordantly, the activity of HIF-driven luciferase reporters was slightly enhanced at pH 7.0. In contrast, HIF target genes exhibited divergent responses to acidosis: basal and hypoxia-induced CA-9 mRNA levels were further increased, whereas hypoxic EPO mRNA induction was attenuated, and Glut-1 mRNA levels were not altered by acidosis. Except from a small increase of hypoxia-induced PHD3 mRNA levels in HeLa cells, there was also no significant effect of acidosis on PHD expression. In conclusion, albeit HIF protein levels slightly induced by acidosis and the inconsistent regulation of HIF target genes under acidosis suggest additional, yet unidentified pH-sensitive factors to be involved in the regulation of these genes.
 ...
PMID:Inconsistent effects of acidosis on HIF-alpha protein and its target genes. 1620 22

Up-regulation of myocardial Nix and BNip3 is associated with apoptosis in cardiac hypertrophy and ischemia, respectively. To identify mechanisms of gene regulation for these critical cardiac apoptosis effectors, the determinants of Nix and BNip3 promoter activation were elucidated by luciferase reporter gene expression in neonatal rat cardiac myocytes. BNip3 transcription was increased by hypoxia but not by phenylephrine (10 microM), angiotensin II (100 nM), or isoproterenol (10 microM). In contrast, Nix transcription was increased by phenylephrine but not by isoproterenol, angiotensin II, or hypoxia. Since phenylephrine stimulates cardiomyocyte hypertrophy via protein kinase C (PKC), the effects of phorbol myristate acetate (PMA, 10 nM for 24 h) and adenoviral PKC expression were assessed. PMA and PKC alpha, but not PKC epsilon or dominant negative PKC alpha, increased Nix transcription. Multiple Nix promoter GC boxes bound transcription factor Sp-1, and basal and PMA- or PKC alpha-stimulated Nix promoter activity was suppressed by mithramycin inhibition of Sp1-DNA interactions. In vivo determinants of Nix expression were evaluated in Nix promoter-luciferase (NixP) transgenic mice that underwent ischemia-reperfusion (1 h/24 h), transverse aortic coarctation (TAC), or cross-breeding with the G(q) overexpression model of hypertrophy. Luciferase activity increased in G alpha(q)-NixP hearts 3.2 +/- 0.4-fold and in TAC hearts 2.8 +/- 0.4-fold but did not increase with infarction-reperfusion. NixP activity was proportional to the extent of TAC hypertrophy and was inhibited by mithramycin. These studies revealed distinct mechanisms of transcriptional regulation for cardiac Nix and BNip3. BNip3 is hypoxia-inducible, whereas Nix expression was induced by G alpha(q)-mediated hypertrophic stimuli. PKC alpha, a G(q) effector, transduced Nix transcriptional induction via Sp1.
 ...
PMID:Distinct pathways regulate proapoptotic Nix and BNip3 in cardiac stress. 1629 51

Hyperbaric oxygen (HBO) is increasingly used in a number of areas of medical practice, such as selected problem infections and wounds. The beneficial effects of HBO in treating ischemia-related wounds may be mediated by stimulating angiogenesis. We sought to investigate VEGF, the main angiogenic regulator, regulated by HBO in human umbilical vein endothelial cells (HUVECs). In this study, we found that VEGF was up regulated both at mRNA and protein levels in HUVECs treated with HBO dose- and time-dependently. Since there are several AP-1 sites in the VEGF promoter, and the c-Jun/AP-1 is activated through stress-activated protein kinase/c-Jun N-terminal kinase (SAPK/JNK) and extracellular signal regulated kinase (ERK), we further examined the c-Jun, JNK and ERK that might be involved in the VEGF induced by HBO. The VEGF mRNA induced by HBO was blocked by both PD98059 and SP600125, the ERK and JNK inhibitors respectively. HBO induced phospho-ERK and phospho-JNK expressions within 15 min. We further demonstrated that c-Jun phosphorylation was induced within 60 min of HBO treatment. HBO also induced the nuclear AP-1 binding ability within 30-60 min, but the AP-1 induction was blocked by treatment with either the ERK or JNK inhibitor. To verify that the VEGF expression induced by HBO is through the AP-1 trans-activation and VEGF promoter, both the VEGF promoter and AP-1 driving luciferase activity were found increased by the cells treated with HBO. The c-Jun mRNA, which is also driven by AP-1, was also induced by HBO, and the induction of c-Jun was blocked by ERK and JNK inhibitors. We suggest that VEGF induced by HBO is through c-Jun/AP-1 activation, and through simultaneous activation of ERK and JNK pathways.
 ...
PMID:Hyperbaric oxygen induces VEGF expression through ERK, JNK and c-Jun/AP-1 activation in human umbilical vein endothelial cells. 1632 81

We examined the inhibition of the expression of some inflammatory genes associated with ischemia-reperfusion (I/R) injury by anthocyanins isolated from black soybean seed coat in tumor necrosis factor-alpha (TNF-alpha)-treated bovine aortic endothelial cells. In addition, its potential use on I/R-injury was investigated using rats subjected to 30-min occlusion of left descending coronary artery followed by 24-h reperfusion. Western blot analysis and luciferase activity assay showed that anthocyanins inhibited TNF-alpha-induced vascular cell adhesion molecule-1, intracellular adhesion molecule-1, and cyclooxygenase-2 levels, which is through NF-kappaB-dependent pathway. Further, anthocyanins protected myocardiac injury from I/R in rats. It is suggested that anthocyanins from black soybean seed coat can be used as a useful drug to modulate cardiovascular disorder.
 ...
PMID:Anthocyanins from soybean seed coat inhibit the expression of TNF-alpha-induced genes associated with ischemia/reperfusion in endothelial cell by NF-kappaB-dependent pathway and reduce rat myocardial damages incurred by ischemia and reperfusion in vivo. 1645 18

Gene therapy with the vascular endothelial growth factor (VEGF) gene is a potential treatment for many disorders or injuries with ischemia. However, unregulated expression of VEGF may induce pathological angiogenesis, promoting tumor growth, diabetic proliferative retinopathy and rupture of atherosclerotic plaque. Therefore, the effective regulation of the gene expression is one of the requirements for the VEGF gene therapy. In this research, we evaluated the hypoxia-inducible gene expression system with the erythropoietin (Epo) enhancer and the Epo 3'-untranslated region (UTR). The luciferase plasmids were constructed with the Epo enhancer (pEpo-SV-Luc), the Epo 3'-UTR (pSV-Luc-EpoUTR) or both (pEpo-SV-Luc-EpoUTR). The polyethylenimine/plasmid complexes were transfected to 293 or A7R5 cells and the cells were incubated under normoxia or hypoxia. The results showed that the Epo enhancer or Epo 3'-UTR increased the target gene expression under hypoxia. pEpo-SV-Luc-EpoUTR showed the highest luciferase expression. The VEGF expression plasmid with the Epo enhancer and 3'-UTR was also constructed. The VEGF expression by pEpo-SV-VEGF-EpoUTR showed the highest specificity of the gene expression in the hypoxic cells. The results suggest that the VEGF plasmid with the Epo enhancer and the Epo 3'-UTR may be useful for gene therapy for ischemic diseases.
 ...
PMID:Hypoxia-inducible gene expression system using the erythropoietin enhancer and 3'-untranslated region for the VEGF gene therapy. 1696 97

Perfluorochemicals (PFCs) have a high solubility for oxygen. We have previously demonstrated the effect of peritoneal lavage with oxygenated PFC (O2-PFC) on ameliorating ischemia/reperfusion (I/R)-induced intestinal ischemic damage in an animal model. In this study, we applied hyperbarically O2-PFC (HBO-PFC) to investigate whether a larger amount of oxygen carried by PFC could enhance the protective effect of O2-PFC during intestinal malperfusion. Rats were subjected to ischemia by clamping the superior mesenteric artery (SMA) for 90 min. The SMA was then declamped. Rats were divided into four groups. In group A, only anesthesia and abdominal incision were performed. In group B, SMA was clamped without O2-PFC. In group C, during the SMA clamp, 1 atm O2-PFC was injected into the abdominal cavity. In group D, 5 atm O2-PFC (HBO-PFC) was prepared using a custom-made hyperbaric oxygen tank and administered to the abdominal cavity during the SMA clamp. Ileal tissue adenosine triphosphate (ATP) levels 90 min after SMA declamping were determined using luciferase assay. To assess intestinal mucosal barrier function at 90 min after release of the SMA clip, everted gut sacs were prepared to measure the mucosal-to-serosal passage of fluorescein-conjugated dextran (FD4, molecular weight = 4 kDa). Thirty minutes after i.p. administration, partial pressure of oxygen in HBO-PFC remained around 1000 mmHg, whereas partial pressure of oxygen in 1 atm O2-PFC decreased to around 400 mmHg. The intestinal tissue ATP was significantly preserved in group D. Moreover, the mucosal hyperpermeability of the gut sac after I/R was significantly ameliorated in group D. Hyperbarically oxygenated perfluorochemical might supply a larger amount of oxygen to ischemic tissue during SMA clamp, which protected the small intestine from I/R injury, possibly caused by the maintenance of tissue ATP levels during ischemia.
 ...
PMID:Intraperitoneal administration of hyperbarically oxygenated perfluorochemical enhances preservation of intestinal mucosa against ischemia/reperfusion injury. 1711 39

The nuclear transcription factor E2F1 plays an important role in modulating neuronal death in response to excitotoxicity and cerebral ischemia. Here, by comparing gene expression in brain cortices from E2F1(+/+) and E2F1(-/-) mice using a custom high-density DNA microarray, we identified a group of putative E2F1 target genes that might be responsible for ischemia-induced E2F1-dependent neuronal death. Neuropilin 1 (NRP-1), a receptor for semaphorin 3A-mediated axon growth cone collapse and retraction, was confirmed to be a direct target of E2F1 based on (i) the fact that the NRP-1 promoter sequence contains an E2F1 binding site, (ii) reactivation of NRP-1 expression in E2F1(-/-) neurons when the E2F1 gene was replaced, (iii) activation of the NRP-1 promoter by E2F1 in a luciferase reporter assay, (iv) electrophoretic mobility gel shift analysis confirmation of the presence of an E2F binding sequence in the NRP-1 promoter, and (v) the fact that a chromatin immunoprecipitation assay showed that E2F1 binds directly to the endogenous NRP-1 promoter. Interestingly, the temporal induction in cerebral ischemia-induced E2F1 binding to the NRP-1 promoter correlated with the temporal-induction profile of NRP-1 mRNA, confirming that E2F1 positively regulates NRP-1 during cerebral ischemia. Functional analysis also showed that NRP-1 receptor expression was extremely low in E2F1(-/-) neurons, which led to the diminished response to semaphorin 3A-induced axonal shortening and neuronal death. An NRP-1 selective peptide inhibitor provided neuroprotection against oxygen-glucose deprivation. Taken together, these findings support a model in which E2F1 targets NRP-1 to modulate axonal damage and neuronal death in response to cerebral ischemia.
 ...
PMID:Neuropilin-1 is a direct target of the transcription factor E2F1 during cerebral ischemia-induced neuronal death in vivo. 1717 35

Recent research has indicated that the protein kinase C (PKC) isoforms and the heat shock proteins (HSPs) are involved in cardioprotection. We have investigated the possible interaction between these two protein families. We have found that adenoviral-mediated expression of PKC-alpha in neonatal rat ventricular myocytes (NRVM) not only increases the expression of HSP70 but also protects against simulated ischemia-reperfusion. In addition, Western blots of PKC-alpha-infected NRVM indicated that other HSPs are not induced in the same manner as HSP70. In an effort to determine the mechanism of induction of HSP70 by PKC-alpha, we tested a chimeric construct that linked the luciferase reporter gene to the 5'-promoter region of HSP70 in myogenic H9c2 cells. When PKC-alpha was expressed, the 5'-promoter region of the HSP70 responded robustly, indicating that PKC-alpha induction of HSP70 expression is through transcription activation. Electrophoretic mobility shift assay determined that overexpression of PKC-alpha, PKC-delta, or PKC-epsilon did not induce activation of heat shock factor-1 (HSF-1). Therefore, induction of HSP70 by PKC-alpha is independent of heat shock factor-1 activation. We also measured cellular injury by assessing creatine kinase (CK) release from NRVM after simulated ischemia to determine cardioprotection. NRVM infected with the wild-type adenoviral construct AdwtPKC-alpha released 54% less CK than control NRVM. Experiments using small interfering RNA against HSP70 indicate that loss of PKC-alpha-induced HSP70 expression results in increased CK release or a loss of protection. Our results show that there is a close interaction between PKC-alpha and HSP70, independent of heat shock factor-1 activation, and that the protection conferred by PKC-alpha overexpression is mediated by the transcriptionally induced expression of HSP70.
 ...
PMID:Influence of PKC-alpha overexpression on HSP70 and cardioprotection. 1720 95

Delivery of the hypoxia-inducible vascular endothelial growth factor (RTP-VEGF) plasmid using a novel reducible disulfide poly(amido ethylenediamine) (SS-PAED) polymer carrier was studied in vitro and in vivo. In vitro transfection of primary rat cardiomyoblasts (H9C2) showed SS-PAED at a weighted ratio of 12:1 (polymer/DNA) mediates 16 fold higher expression of luciferase compared to an optimized bPEI control. FACS analysis revealed up to 57+/-2% GFP positive H9C2s. The efficiency of plasmid delivery to H9C2 using SS-PAED was found to depend upon glutathione (GSH) levels inside the cell. SS-PAED mediated delivery of RTP-VEGF plasmid produced significantly higher levels of VEGF expression (up to 76 fold) under hypoxic conditions compared to normoxic conditions in both H9C2 and rat aortic smooth muscle cells (A7R5). Using SS-PAED, delivery of RTP-VEGF was investigated in a rabbit myocardial infarct model using 100 mug RTP-VEGF. Results showed up to 4 fold increase in VEGF protein expression in the region of the infarct compared to injections of SS-PAED/RTP-Luc. In conclusion, SS-PAED mediated therapeutic delivery improves the efficacy of ischemia-inducible VEGF gene therapy both in vitro and in vivo and therefore, has potential for the promotion of neo-vascular formation and improvement of tissue function in ischemic myocardium.
 ...
PMID:Reducible poly(amido ethylenediamine) for hypoxia-inducible VEGF delivery. 1727 36

Cellular prion protein (PrP(C)), a copper-binding glycosyl-phosphatidylinositol (GPI)-anchored membrane protein that is expressed predominantly in neurons can be induced in ischemia/hypoxic brain tissues. It was also found to be overexpressed and conferred multidrug resistance, promoting cancer metastasis and inhibiting apoptosis in gastric cancer in our lab. In solid tumors, hypoxia can promote malignant progression and confer resistance to chemotherapy by altering gene expression. In present study, we investigated the molecular mechanisms and signaling pathway involved in the induction of the PrP(C) gene by hypoxia in cancer cell lines. PrP(C) was detected to be upregulated in several cancer cell lines at both mRNA and protein level, and then found to be induced by hypoxia in a time-dependent manner. After hypoxia treatment, gastric cancer MKN28 cells transfected with luciferase reporter constructs of the human PrP(C) promoter, which contained HSE, expressed higher luciferase activities (4.3-fold) than those cells transfected with the constructs containing no HSE. In addition, the upregulation of PrP(C) was reduced by MERK/ERK inhibitor (PD98059). siRNA knockdown of PrP(C) could make the cells more sensitive to hypoxia induced drug sensitivity. In conclusion, from these findings, we can propose that some transcriptional factors phosphorylated by ERK1/2, could in turn interact with HSE in the promoter of PrP(C) resulting in upregulation of PrP(C) in gastric cancer cell line MKN28 during hypoxia. Downregulation of PrP(C) makes gastric cancer cells more sensitive to hypoxia induced drug sensitivity. However, other mechanisms might also be responsible for hypoxia induced overexpression of PrP(C) in gastric cancer.
 ...
PMID:Hypoxia induced overexpression of PrP(C) in gastric cancer cell lines. 1738 71


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>