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1.
Int. braz. j. urol ; 47(2): 295-305, Mar.-Apr. 2021. tab, graf
Article in English | LILACS | ID: biblio-1154442

ABSTRACT

ABSTRACT The standard treatment for locally advanced cervical cancer (CC) is chemoradiotherapy. Once the bladder receives part of the radiation, a typical inflammatory condition that configures radiation-induced cystitis may develop. Chronic radiation-induced cystitis is commonly characterized by the bladder new submucosal vascularization, which is typically fragile and favors hematuria. The current study aims to investigate if Hypoxia-Induced Factor (HIF-1α) and its transcriptional target Vascular Endothelial Growth Factor A (VEGF-A) could be a primary pathway leading to increased submucosal vascularization. HIF-1α and VEGF-A mRNA levels in bladder core biopsies from CC patients treated with radiotherapy versus untreated (non-irradiated) patients were analyzed using a droplet digital polymerase chain reaction technology. Gene expression results showed that HIF-1α and VEGF-A had no significant differences between bladder samples from patients previously irradiated and untreated patient samples. However, a direct relationship between the degree of late morbidity and the expression of HIF-1α and VEGF-A has been demonstrated. Despite the lack of statistical significance precludes a definitive conclusion, the data presented herein suggests that further studies investigating the role of HIF-1α in bladder neovascularization in radiation-induced cystitis are highly recommended.


Subject(s)
Humans , Female , Uterine Cervical Neoplasms , Cystitis/etiology , Case-Control Studies , Vascular Endothelial Growth Factor A , Hypoxia-Inducible Factor 1, alpha Subunit/genetics , Neovascularization, Pathologic
2.
Article in English | WPRIM | ID: wpr-880664

ABSTRACT

OBJECTIVES@#To analyze the expressions and distributions of hypoxia-inducible factor-1α (HIF-1α), CD147, and glucose transporter 1 (GLUT1) in epidermis from psoriasis vulgaris and normal people, and to explore the associations among these proteins and their roles in hypoxic HaCaT cell line.@*METHODS@#The expression levels of HIF-1α, CD147, and GLUT1 were determined by immunohistochemistry staining in skin biopsies from 48 psoriasis vularis patients and 33 healthy subjects. Cobalt chloride (CoCl@*RESULTS@#HIF-1α, CD147, and GLUT1 were highly expressed and the glycolytic capacity was increased in lesions of psoriasis vulgaris; HIF-1α upregulated the expression of CD147 and GLUT1, increased the lactate production and decreased the ATP level in CoCl@*CONCLUSIONS@#Glycolytic capacity increases in the injured keratinocytes of psoriasis vulgaris, suggesting that HIF-1α, CD147, and GLUT1 are associated with glycolysis, which can be considered as the promising targets for psoriasis therapy.


Subject(s)
Basigin , Glucose Transporter Type 1 , Glycolysis , Humans , Hypoxia-Inducible Factor 1, alpha Subunit/genetics , Psoriasis/genetics , Transcriptional Activation , Up-Regulation
3.
Acta Physiologica Sinica ; (6): 26-34, 2021.
Article in Chinese | WPRIM | ID: wpr-878232

ABSTRACT

Intermittent hypoxia (IH) could induce cognitive impairment through oxidative stress and inflammation. However, the degree of cell damage is closely related to the IH stimulus frequency. IH stimulation with different frequencies also induces opposite results on neuronal cell lines. Therefore, this study was aimed to compare the effects of IH stimulation with three different frequencies on murine hippocampal neuronal HT22 cell activity, and to explore the molecular mechanism of the IH stimulus frequency-related neuron injury. HT22 cells were cultured and divided into control group and three IH stimulation groups with different frequencies. Oxygen concentration in the chamber was circulated between 21% and 1% (IH1 group, 6 cycles/h; IH2 group, 2 cycles/h; IH3 group, 0.6 cycle/h). Cell morphology was observed at 6, 12, 24 and 48 h of IH treatment. Cell viability was determined by the CCK-8 kit, lactate dehydrogenase (LDH) content in cell supernatant was determined by LDH kit, oxidative stress level was detected by the reactive oxygen species (ROS) probe, and protein expression levels of hypoxia inducible factor-1α (Hif-1α) and phosphorylated nuclear factor κB (p-NF-κB) were detected by Western blot. The results showed that, compared with control group, cell number and activity in the three IH groups were decreased, LDH content and ROS levels were increased with the prolongation of IH stimulation time, and the changes were most obvious in the IH1 group among those of the three IH groups. Hif-1α expression and the p-NF-κB/NF-κB ratio were also up-regulated with the prolongation of IH stimulation time, and the changes of IH1 group were the most significant. These results suggest that IH stimulation induces oxidative stress injury in HT22 cells, which is related to increased Hif-1α expression and NF-κB phosphorylation. Moreover, the higher frequency of IH stimulation induces more serious cell injury.


Subject(s)
Animals , Cell Hypoxia , Cell Survival , Hypoxia , Hypoxia-Inducible Factor 1, alpha Subunit/genetics , Mice , NF-kappa B/metabolism , Oxidative Stress , Reactive Oxygen Species
4.
Article in English | WPRIM | ID: wpr-880580

ABSTRACT

OBJECTIVES@#Peroxisome proliferator-activated receptor gamma coactivator 1α (PGC1α) controls mitochondrial biogenesis, but its role in cardiovascular diseases is unclear. The purpose of this study is to explore the effect of PGC1α on myocardial ischemia-reperfusion injury and the underlying mechanisms.@*METHODS@#The transverse coronary artery of SD rat was ligated for 30 minutes followed by 2 hours of reperfusion. Triphenyltetrazolium chloride (TTC) staining was performed to measure the area of myocardial infarction. Immunohistochemistry and Western blotting were used to detect the PGC1α expression in myocardium. The rat cardiomyocyte H9C2 was subjected to hypoxia/reoxygenation (H/R) with the knockdown of PGC1α or hypoxia- inducible factor 1α (HIF-1α), or with treatment of metformin. Western blotting was used to detect the expression of PGC1α, HIF-1α, p21, BAX, and caspase-3. CCK-8 was performed to detect cell viability, and flow cytometry was used to detect apoptosis and mitochondrial superoxide (mitoSOX) release. RT-qPCR was used to detect the mRNA expression of PGC1α and HIF-1α. Besides, chromatin immunoprecipitation (ChIP)-qPCR and luciferase reporter gene assay were applied to detect the transcriptional regulation effect of HIF-1α on PGC1α.@*RESULTS@#After I/R, the PGC1α expression was increased in infarcted myocardium. H/R induced H9C2 cell apoptosis (@*CONCLUSIONS@#After I/R, HIF-1α up-regulates the expression of PGC1α, leading to an increase in ROS production and aggravation of injury. Metformin can inhibit the accumulation of HIF-1α during hypoxia and effectively protect myocardium from ischemia/reperfusion injury.


Subject(s)
Animals , Apoptosis , Hypoxia-Inducible Factor 1, alpha Subunit/genetics , Myocardial Reperfusion Injury/genetics , Myocytes, Cardiac/metabolism , Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha/metabolism , Rats , Rats, Sprague-Dawley , Reperfusion Injury
5.
Braz. dent. j ; 29(2): 179-183, Mar.-Apr. 2018. tab
Article in English | LILACS | ID: biblio-951532

ABSTRACT

Abstract Persistent apical periodontitis (AP) is a situation involving an inflammatory and immune response caused mainly by anaerobic polymicrobial infection of the root canal system and the outcome and follow-up of the root canal treatment has been reported as intimately related to host response. The apical periodontitis repair might be associated with genetic polymorphisms. This study aimed to evaluate the association between HIF1A genetic polymorphisms (rs2301113 and rs2057482) with PAP in Brazilian patients. Subjects with at least 1 year of follow-up after root canal therapy (RCT) were recalled. Sixty-four subjects with signs/symptoms of PAP and 84 subjects with root canal-treated teeth exhibiting healthy perirradicular tissues (healed) were included. Genomic DNA was extracted from saliva and used for HIF1A genotyping by real-time PCR. Genotype and allele frequencies were compared by c2 or Fisher's exact tests and odds ratio was implemented, using Epi Info 3.5.2. All tests were performed with an established alpha of 0.05. There was no association between allele and genotype distribution for HIF1As polymorphisms and PAP (p>0.05). The genetic polymorphisms in HIF1A were not associated with persistent apical periodontitis.


Resumo A periodontite apical persistente (PAP) é uma condição que envolve uma resposta inflamatória e imunológica causada principalmente por infecções polimicrobianas de origem anaeróbia no sistema de canais radiculares, tornando o resultado e o acompanhamento do tratamento do canal radicular intimamente relacionados à resposta do hospedeiro. O reparo da periodontite apical pode estar associado a polimorfismos genéticos. Este estudo teve como objetivo avaliar a associação entre os polimorfismos genéticos do HIF1A (rs2301113 e rs2057482) com a PAP em pacientes brasileiros. Indivíduos com pelo menos 1 ano de acompanhamento após o tratamento do canal radicular (TCR) foram agendados para consulta de acompanhamento. Sessenta e quatro indivíduos com sinais/sintomas de PAP e 84 indivíduos com dentes tratados endodonticamente e tecidos perirradiculares saudáveis (cicatrizados) foram incluídos no presente estudo. O DNA genômico foi extraído da saliva e utilizado para a genotipagem do HIF1A por PCR em tempo real. O genótipo e as frequências alélicas foram comparados por teste c2 ou exato de Fisher e odds-ratio foi implementado por meio do software Epi Info 3.5.2. Todos os testes realizados foram estabelecidos com a=0,05. Não houve associação entre alelo e distribuição genotípica para polimorfismos do HIF1A e PAP (p> 0,05). Os polimorfismos genéticos em HIF1A não foram associados à periodontite apical persistente.


Subject(s)
Humans , Male , Female , Adult , Middle Aged , Periapical Periodontitis/genetics , Polymorphism, Genetic , Bone Remodeling/genetics , Hypoxia-Inducible Factor 1, alpha Subunit/genetics , Neovascularization, Pathologic/genetics , Periapical Periodontitis/pathology , Root Canal Therapy , Brazil , DNA/genetics , Real-Time Polymerase Chain Reaction , Gene Frequency , Genotype
6.
J. appl. oral sci ; 26: e20170234, 2018. tab, graf
Article in English | LILACS | ID: biblio-893716

ABSTRACT

Abstract Objectives To evaluate the association between hypoxia during embryo development and oral clefts in an animal model, and to evaluate the association between polymorphisms in the HIF-1A gene with oral clefts in human families. Material and Methods The study with the animal model used zebrafish embryos at 8 hours post-fertilization submitted to 30% and 50% hypoxia for 24 hours. At 5 days post-fertilization, the larvae were fixed. The cartilage structures were stained to evaluate craniofacial phenotypes. The family-based association study included 148 Brazilian nuclear families with oral clefts. The association between the genetic polymorphisms rs2301113 and rs2057482 in HIF-1A with oral clefts was tested. We used real time PCR genotyping approach. ANOVA with Tukey's post-test was used to compare means. The transmission/disequilibrium test was used to analyze the distortion of the inheritance of alleles from parents to their affected offspring. Results For the hypoxic animal model, the anterior portion of the ethmoid plate presented a gap in the anterior edge, forming a cleft. The hypoxia level was associated with the severity of the phenotype (p<0.0001). For the families, there was no under-transmitted allele among the affected progeny (p>0.05). Conclusion Hypoxia is involved in the oral cleft etiology, however, polymorphisms in HIF-1A are not associated with oral clefts in humans.


Subject(s)
Humans , Animals , Male , Female , Child, Preschool , Child , Adolescent , Adult , Aged , Young Adult , Polymorphism, Genetic , Cleft Lip/embryology , Cleft Lip/etiology , Cleft Palate/embryology , Cleft Palate/etiology , Hypoxia-Inducible Factor 1, alpha Subunit/genetics , Fetal Hypoxia/complications , Severity of Illness Index , Zebrafish , Analysis of Variance , Statistics, Nonparametric , Disease Models, Animal , Genetic Association Studies , Fetal Hypoxia/genetics , Real-Time Polymerase Chain Reaction , Middle Aged
7.
Yonsei Medical Journal ; : 1503-1514, 2015.
Article in English | WPRIM | ID: wpr-177076

ABSTRACT

PURPOSE: Although follicular thyroid cancer (FTC) has a relatively fair prognosis, distant metastasis sometimes results in poor prognosis and survival. There is little understanding of the mechanisms contributing to the aggressiveness potential of thyroid cancer. We showed that hypoxia inducible factor-1alpha (HIF-1alpha) induced aggressiveness in FTC cells and identified the underlying mechanism of the HIF-1alpha-induced invasive characteristics. MATERIALS AND METHODS: Cells were cultured under controlled hypoxic environments (1% O2) or normoxic conditions. The effect of hypoxia on HIF-1alpha, and epithelial-to-mesenchymal transition (EMT) related markers were evaluated by quantitative real-time PCR, Western blot analysis and immunocytochemistry. Invasion and wound healing assay were conducted to identify functional character of EMT. The involvement of HIF-1alpha and Twist in EMT were studied using gene overexpression or silencing. After orthotopic nude mouse model was established using the cells transfected with lentiviral shHIF-1alpha, tissue analysis was done. RESULTS: Hypoxia induces HIF-1alpha expression and EMT, including typical morphologic changes, cadherin shift, and increased vimentin expression. We showed that overexpression of HIF-1alpha via transfection resulted in the aforementioned changes without hypoxia, and repression of HIF-1alpha with RNA interference suppressed hypoxia-induced HIF-1alpha and EMT. Furthermore, we also observed that Twist expression was regulated by HIF-1alpha. These were confirmed in the orthotopic FTC model. CONCLUSION: Hypoxia induced HIF-1alpha, which in turn induced EMT, resulting in the increased capacity for invasion and migration of cells via regulation of the Twist signal pathway in FTC cells. These findings provide insight into a possible therapeutic strategy to prevent invasive and metastatic FTC.


Subject(s)
Adenocarcinoma, Follicular/genetics , Animals , Hypoxia/genetics , Cadherins/genetics , Epithelial-Mesenchymal Transition/genetics , Gene Expression Regulation, Neoplastic , Hypoxia-Inducible Factor 1, alpha Subunit/genetics , Lymphokines , Mice , Neoplasm Invasiveness , Phenotype , Real-Time Polymerase Chain Reaction , Signal Transduction/drug effects , Thyroid Neoplasms/genetics , Transcriptional Activation , Twist-Related Protein 1/genetics , Vimentin/metabolism
8.
Article in English | WPRIM | ID: wpr-113787

ABSTRACT

Growth factor-stimulated phospholipase D (PLD) catalyzes the hydrolysis of phosphatidylcholine (PC), generating phosphatidic acid (PA) which may act as a second messenger during cell proliferation and survival. Therefore, PLD is believed to play an important role in tumorigenesis. In this study, a potential mechanism for PLD-mediated tumorigenesis was explored. Ectopic expression of PLD1 or PLD2 in human glioma U87 cells increased the expression of hypoxia-inducible factor-1alpha (HIF-1alpha) protein. PLD-induced HIF-1 activation led to the secretion of vascular endothelial growth factor (VEGF), a HIF-1 target gene involved in tumorigenesis. PLD induction of HIF-1alpha was significantly attenuated by 1-butanol which blocks PA production by PLD, and PA per se was able to elevate HIF-1alpha protein level. Inhibition of mTOR, a PA-responsive kinase, reduced the levels of HIF-1alpha and VEGF in PLD-overexpressed cells. Epidermal growth factor activated PLD and increased the levels of HIF-1alpha and VEGF in U87 cells. A specific PLD inhibitor abolished expression of HIF-1alpha and secretion of VEGF. PLD may utilize HIF-1-VEGF pathway for PLD-mediated tumor cell proliferation and survival.


Subject(s)
Cell Line, Tumor , Epidermal Growth Factor/metabolism , Gene Expression Regulation, Neoplastic , Glioma/genetics , Humans , Hypoxia-Inducible Factor 1, alpha Subunit/genetics , Phosphatidic Acids/metabolism , Phospholipase D/genetics , Signal Transduction , Transfection , Vascular Endothelial Growth Factor A/metabolism
9.
Article in English | WPRIM | ID: wpr-51697

ABSTRACT

The expression of hypoxia-inducible factor (HIF) is influenced by reactive oxygen species (ROS). Effect of bilirubin on HIF-1 expression in proximal tubular cells was investigated under physiological oxygen concentration, which is relative hypoxic condition mimicking oxygen content in the medulla of renal tissue. The human kidney (HK2) cells were cultured in 5% oxygen with or without bilirubin. HIF-1alpha protein expression was increased by bilirubin treatment at 0.01-0.2 mg/dL concentration. The messenger RNA expression of HIF-1alpha was increased by 1.69+/-0.05 folds in the cells cultured with 0.1 mg/dL bilirubin, compared to the control cells. The inhibitors of PI3K/mTOR, PI3K/AKT, and ERK 1/2 pathways did not attenuate increased HIF-1alpha expression by bilirubin. HIF-1alpha expression decreased by 10 microM exogenous hydrogen peroxide (H2O2); scavenger of ROS with or without bilirubin in the HK2 cells increased HIF-1alpha concentration more than that in the cells without bilirubin. Exogenous H2O2 decreased the phosphorylation of P70S6 kinase, which was completely reversed by bilirubin treatment. Knockdown of NOX4 gene by small interfering RNA (siRNA) increased HIF-1alpha mRNA expression. In coonclusion, bilirubin enhances HIF-1alpha transcription as well as the up-regulation of HIF-1alpha protein translation through the attenuation of ROS and subunits of NADPH oxidase.


Subject(s)
Bilirubin/pharmacology , Cell Line , Epithelial Cells/cytology , Humans , Hydrogen Peroxide/toxicity , Hypoxia-Inducible Factor 1, alpha Subunit/genetics , Kidney Tubules, Proximal/cytology , Mitogen-Activated Protein Kinase 1/metabolism , Mitogen-Activated Protein Kinase 3/metabolism , NADPH Oxidases/antagonists & inhibitors , Oxygen/pharmacology , Phosphatidylinositol 3-Kinases/metabolism , Phosphorylation/drug effects , Proto-Oncogene Proteins c-akt/metabolism , RNA Interference , Ribosomal Protein S6 Kinases, 70-kDa/metabolism , Signal Transduction/drug effects , TOR Serine-Threonine Kinases/metabolism , Transcriptional Activation/drug effects , Up-Regulation/drug effects
10.
Biol. Res ; 46(2): 169-176, 2013. graf, tab
Article in English | LILACS | ID: lil-683994

ABSTRACT

This study analyzed the time dependence decay of the mRNA of selected genes important for the hypoxia response. The genes chosen were the two isoforms of hypoxia-inducible factors, the three isoforms of the prolyl hydroxylase domain protein, the vascular endothelial growth factor and endothelial nitric oxide synthase. mRNA and proteins were extracted from lungs obtained from control, hypoxic and 15 minutes normoxic recovered rats and analyzed by Real-time RT-PCR or by the Western Blot technique. Results indicated that in normoxia isoform 2á was the more represented hypoxia-inducible factor mRNA, and among the prolyl hydroxylase domain transcripts, isoform 3 was the least abundant. Moreover, in chronic hypoxia only hypoxia-inducible factor 1α and prolyl hydroxylase domain protein 3 increased significantly, while after 15 minutes of recovery all the mRNAs tested were decreased except endothelial nitric oxide synthase mRNA. In terms of proteins, hypoxia-inducible 1α was the isoform more significant in the nucleus, while 2á predominated in the cytosol. While the former was steady even after a brief recovery from hypoxia, the latter underwent a strong degradation. In conclusion we showed the relevance of the decay in the mRNA and protein levels upon re-oxygenation in normoxia. We believe that this has to be considered in research studies dealing with recovery from hypoxia.


Subject(s)
Animals , Male , Hypoxia/genetics , Lung/metabolism , RNA, Messenger/metabolism , Transcription, Genetic/genetics , Blotting, Western , Hypoxia-Inducible Factor 1, alpha Subunit/genetics , Hypoxia-Inducible Factor 1, alpha Subunit/metabolism , Nitric Oxide Synthase Type III/genetics , Nitric Oxide Synthase Type III/metabolism , Procollagen-Proline Dioxygenase/genetics , Procollagen-Proline Dioxygenase/metabolism , Rats, Wistar , Real-Time Polymerase Chain Reaction , Vascular Endothelial Growth Factor A/genetics , Vascular Endothelial Growth Factor A/metabolism
11.
Article in English | WPRIM | ID: wpr-219416

ABSTRACT

The use of mesenchymal stem cells (MSCs) has emerged as a potential new treatment for myocardial infarction. However, the poor viability of MSCs after transplantation critically limits the efficacy of this new strategy. The expression of microRNA-210 (miR-210) is induced by hypoxia and is important for cell survival under hypoxic conditions. Hypoxia increases the levels of hypoxia inducible factor-1 (HIF-1) protein and miR-210 in human MSCs (hMSCs). miR-210 positively regulates HIF-1alpha activity. Furthermore, miR-210 expression is also induced by hypoxia through the regulation of HIF-1alpha. To investigate the effect of miR-210 on hMSC survival under hypoxic conditions, survival rates along with signaling related to cell survival were evaluated in hMSCs over-expressing miR-210 or ones that lacked HIF-1alpha expression. Elevated miR-210 expression increased survival rates along with Akt and ERK activity in hMSCs with hypoxia. These data demonstrated that a positive feedback loop involving miR-210 and HIF-1alpha was important for MSC survival under hypoxic conditions.


Subject(s)
Cell Survival , Cobalt , Gene Expression Regulation/physiology , Humans , Hypoxia-Inducible Factor 1, alpha Subunit/genetics , Mesenchymal Stem Cells/drug effects , MicroRNAs/metabolism , Oxygen/pharmacology , Oxygen Consumption , RNA, Small Interfering/metabolism
12.
Article in English | WPRIM | ID: wpr-71813

ABSTRACT

With the increasing use of culture-expanded mesenchymal stromal cells (MSCs) for cell therapies, factors that regulate the cellular characteristics of MSCs have been of major interest. Oxygen concentration has been shown to influence the functions of MSCs, as well as other normal and malignant stem cells. However, the underlying mechanisms of hypoxic responses and the precise role of hypoxia-inducible factor-1alpha (Hif-1alpha), the master regulatory protein of hypoxia, in MSCs remain unclear, due to the limited span of Hif-1alpha stabilization and the complex network of hypoxic responses. In this study, to further define the significance of Hif-1alpha in MSC function during their self-renewal and terminal differentiation, we established adult bone marrow (BM)-derived MSCs that are able to sustain high level expression of ubiquitin-resistant Hif-1alpha during such long-term biological processes. Using this model, we show that the stabilization of Hif-1alpha proteins exerts a selective influence on colony-forming mesenchymal progenitors promoting their self-renewal and proliferation, without affecting the proliferation of the MSC mass population. Moreover, Hif-1alpha stabilization in MSCs led to the induction of pluripotent genes (oct-4 and klf-4) and the inhibition of their terminal differentiation into osteogenic and adipogenic lineages. These results provide insights into the previously unrecognized roles of Hif-1alpha proteins in maintaining the primitive state of primary MSCs and on the cellular heterogeneities in hypoxic responses among MSC populations.


Subject(s)
Cell Differentiation , Cell Proliferation , Humans , Hypoxia-Inducible Factor 1, alpha Subunit/genetics , Kruppel-Like Transcription Factors/genetics , Mesenchymal Stem Cells/cytology , Octamer Transcription Factor-3/genetics , Protein Stability
13.
Clinics ; 67(1): 35-40, 2012. ilus
Article in English | LILACS | ID: lil-610621

ABSTRACT

OBJECTIVE: Hypoxia-inducible factor 1 alpha regulates genes related to cellular survival under hypoxia. This factor is present in osteroarthritic chondrocytes, and cytokines, such as interleukin-1 beta, participate in the pathogenesis of osteoarthritis, thereby increasing the activities of proteolytic enzymes, such as matrix metalloproteinases, and accelerating cartilage destruction. We hypothesize that Hypoxia Inducible Factor-1 alpha (HIF-1α) can regulate cytokines (catabolic action) and/or growth factors (anabolic action) in osteoarthritis. The purpose of this study was to investigate the modulation of HIF-1α in human osteoarthritic chondrocytes by interleukin-1 beta (IL-1β) and insulin-like growth factors I (IGF-I) and II (IGF-II) and to determine the involvement of the phosphatidylinositol-3kinase (PI-3K) pathway in this process. METHODS: Human osteroarthritic chondrocytes were stimulated with IL-1β, IGF-I and IGF-II and LY294002, a specific inhibitor of PI-3K. Nuclear protein levels and gene expression were analyzed by western blot and quantitative reverse transcription-polymerase chain reaction analyses, respectively. RESULTS: HIF-1α expression was upregulated by IL-1β at the protein level but not at the gene level. IGF-I treatment resulted in increases in both the protein and mRNA levels of HIF-1α , whereas IGF-II had no effect on its expression. However, all of these stimuli exploited the PI-3K pathway. CONCLUSION: IL-1β upregulated the levels of HIF-1α protein post-transcriptionally, whereas IGF-I increased HIF-1α at the transcript level. In contrast, IGF-II did not affect the protein or gene expression levels of HIF-1α . Furthermore, all of the tested stimuli exploited the PI-3K pathway to some degree. Based on these findings, we are able to suggest that Hypoxia inducible Factor-1 exhibits protective activity in chondrocytes during osteoarthritis.


Subject(s)
Humans , Chondrocytes/drug effects , Gene Expression Regulation/drug effects , Hypoxia-Inducible Factor 1, alpha Subunit/metabolism , Insulin-Like Growth Factor I/pharmacology , Insulin-Like Growth Factor II/pharmacology , Interleukin-1beta/pharmacology , Osteoarthritis/metabolism , Chondrocytes/metabolism , Enzyme Inhibitors/pharmacology , Gene Expression Regulation/genetics , Hypoxia-Inducible Factor 1, alpha Subunit/genetics , Osteoarthritis/genetics , /antagonists & inhibitors , /metabolism , RNA, Messenger/analysis , Statistics, Nonparametric , Signal Transduction/drug effects , Signal Transduction/genetics
14.
Article in English | WPRIM | ID: wpr-28115

ABSTRACT

BACKGROUND/AIMS: Renal hypoxia is involved in the pathogenesis of diabetic nephropathy. Pentoxifyllin (PTX), a nonselective phosphodiesterase inhibitor, is used to attenuate peripheral vascular diseases. To determine whether PTX can improve renal hypoxia, we investigated its effect in the streptozocin (STZ)-induced diabetic kidney. METHODS: PTX (40 mg/kg, PO) was administered to STZ-induced diabetic rats for 8 weeks. To determine tissue hypoxia, we examined hypoxic inducible factor-1alpha (HIF-1alpha), heme oxygenase-1 (HO-1), vascular endothelial growth factor (VEGF), and glucose transporter-1 (GLUT-1) levels. We also tested the effect of PTX on HIF-1alpha in renal tubule cells. RESULTS: PTX reduced the increased protein creatinine ratio in diabetic rats at 8 weeks. HIF-1alpha, VEGF, and GLUT-1 mRNA expression increased significantly, and the expression of HO-1 also tended to increase in diabetic rats. PTX significantly decreased mRNA expression of HIF-1alpha and VEGF at 4 and 8 weeks, and decreased HO-1 and GLUT-1 at 4 weeks. The expression of HIF-1alpha protein was significantly increased at 4 and 8 weeks in tubules in the diabetic rat kidney. PTX tended to decrease HIF-1alpha protein expression at 8 weeks. To examine whether PTX had a direct effect on renal tubules, normal rat kidney cells were stimulated with CoCl2 (100 microM), which enhanced HIF-1alpha mRNA and protein levels under low glucose conditions (5.5 mM). Their expressions were similar even after high glucose (30 mM) treatment. PTX had no effect on HIF-1alpha expression. CONCLUSIONS: PTX attenuates tubular hypoxia in the diabetic kidney.


Subject(s)
Animals , Hypoxia/drug therapy , Cell Line , Cobalt/pharmacology , Diabetes Mellitus, Experimental/complications , Diabetic Nephropathies/drug therapy , Disease Models, Animal , Gene Expression Regulation/drug effects , Glucose/metabolism , Glucose Transporter Type 1/genetics , Heme Oxygenase (Decyclizing)/genetics , Hypoxia-Inducible Factor 1, alpha Subunit/genetics , Kidney Tubules/drug effects , Male , Pentoxifylline/pharmacology , Phosphodiesterase Inhibitors/pharmacology , RNA, Messenger/metabolism , Rats , Rats, Sprague-Dawley , Streptozocin , Time Factors , Vascular Endothelial Growth Factor A/genetics
15.
Article in English | WPRIM | ID: wpr-43808

ABSTRACT

Hypoxia-inducible factors (HIFs) are transcription factors that activate the transcription of target genes involved in crucial aspects of cancer development. This study investigated the expression of HIFs and their contribution to the regulation of target genes related to angiogenesis and glucose metabolism in gastric cancer. The data showed that HIFs were over-expressed in gastric cancer and that activation of the target genes was observed mainly in the early stages. Moreover, the results of the present study revealed that only HIF-1alpha, but not HIF-2alpha dimerizes with HIF-1beta and then regulates expression of target genes in response to hypoxia. The results of the present study demonstrate that HIF-1alpha and HIF-1beta enhances expression of VEGF and glucose metabolism-related genes in response to hypoxia in gastric cancer. These data offer important information regarding HIF pathways in the development of gastric cancer.


Subject(s)
Aryl Hydrocarbon Receptor Nuclear Translocator/genetics , Basic Helix-Loop-Helix Transcription Factors/genetics , Cell Line, Tumor , Gene Expression Regulation, Neoplastic , Glucose/metabolism , Humans , Hypoxia-Inducible Factor 1, alpha Subunit/genetics , Neovascularization, Pathologic/genetics , Stomach Neoplasms/genetics , Vascular Endothelial Growth Factor A/genetics
16.
Article in English | WPRIM | ID: wpr-77112

ABSTRACT

In this study, we investigated the role of Nur77, an orphan nuclear receptor, in HIF-alpha transcriptional activity. We found that Nur77 associates and stabilizes HIF-1alpha via indirect interaction. Nur77 was found to interact with pVHL in vivo via the alpha-domain of pVHL. By binding to pVHL, Nur77 competed with elongin C for pVHL binding. Moreover, Nur77-binding to pVHL inhibited the pVHL-mediated ubiquitination of HIF-1alpha and ultimately increased the stability and transcriptional activity of HIF-1alpha. The ligand-binding domain of Nur77 was found to interact with pVHL and the expression of this ligand-binding domain was sufficient to stabilize and transactivate HIF-1alpha. Under the conditions that cobalt chloride was treated or pVHL was knocked down, Nur77 could not stabilize HIF-alpha. Moreover, Nur77 could not further stabilize HIF-2alpha in A498/VHL stable cells, which is consistent with our finding that Nur77 indirectly stabilizes HIF-alpha by binding to pVHL. Thus, our results suggest that an orphan nuclear receptor Nur77 binds to pVHL, thereby stabilizes and increases HIF-alpha transcriptional activity under the non- hypoxic conditions.


Subject(s)
Animals , DNA-Binding Proteins/chemistry , Humans , Hypoxia-Inducible Factor 1, alpha Subunit/genetics , Models, Biological , PC12 Cells , Protein Binding , Protein Processing, Post-Translational , Protein Structure, Tertiary , Rats , Receptors, Cytoplasmic and Nuclear/chemistry , Receptors, Steroid/chemistry , Thermodynamics , Transcription Factors/chemistry , Transcriptional Activation/genetics , Ubiquitination , Up-Regulation/genetics , Von Hippel-Lindau Tumor Suppressor Protein/antagonists & inhibitors
17.
Article in English | WPRIM | ID: wpr-84655

ABSTRACT

Hypoxia-inducible factor 1alpha (HIF-1alpha) is rapidly degraded by the ubiquitin-proteasome pathway under normoxic conditions. Ubiquitination of HIF-1alpha is mediated by interaction with von Hippel-Lindau tumor suppressor protein (pVHL). In our previous report, we found that hypoxia-induced active signal transducer and activator of transcription3 (STAT3) accelerated the accumulation of HIF-1alpha protein and prolonged its half-life in solid tumor cells. However, its specific mechanisms are not fully understood. Thus, we examined the role of STAT3 in the mechanism of pVHL-mediated HIF-1alpha stability. We found that STAT3 interacts with C-terminal domain of HIF-1alpha and stabilizes HIF-1alpha by inhibition of pVHL binding to HIF-1alpha. The binding between HIF-1alpha and pVHL, negative regulator of HIF-1alpha stability, was interfered dose-dependently by overexpressed constitutive active STAT3. Moreover, we found that the enhanced HIF-1alpha protein levels by active STAT3 are due to decrease of poly-ubiquitination of HIF-1alpha protein via inhibition of interaction between pVHL and HIF-1alpha. Taken together, our results suggest that STAT3 decreases the pVHL-mediated ubiquitination of HIF-1alpha through competition with pVHL for binding to HIF-1alpha, and then stabilizes HIF-1alpha protein levels.


Subject(s)
Animals , COS Cells , Cell Line, Tumor , Chlorocebus aethiops , Humans , Hypoxia-Inducible Factor 1, alpha Subunit/genetics , Immunoblotting , Immunoprecipitation , Protein Binding , STAT3 Transcription Factor/genetics , Signal Transduction/genetics , Transfection , Ubiquitination , Von Hippel-Lindau Tumor Suppressor Protein/genetics
18.
Yonsei Medical Journal ; : 295-300, 2008.
Article in English | WPRIM | ID: wpr-30671

ABSTRACT

PURPOSE: Hypoxia-inducible factor-1alpha (HIF-1alpha) primarily mediates the hypoxic response. HIF-1alpha induction by various stimuli contributes to cell proliferation and survival. To investigate the effect of HIF-1alpha, we used small interfering RNA (siRNA), and expected that cell apoptosis and sensitivity to chemotherapeutic drug increase, when we blocked the HIF-1alpha gene. Thus we performed in vitro and in vivo experiment to clarify the effect of hypoxia-inducible factor-1alpha on tumor growth. MATERIALS AND METHODS: We made control and HIF-1alpha siRNA using vector plasmid and then transfected Mia-paca cell lines with these RNAs. After selection with geneticin, two new cell lines were made, confirmed via immunoblotting. After treating with gemcitabine, each cell line was assayed to confirm the effect of HIF-1alpha siRNA using the cell proliferation assay and capase-3 assay. And then in vivo study was performed using female athymic nude mice. After subcutaneously injecting each new cell lines, intraperitoneal gemicitabine chemotherapy was performed for 3 weeks. During that period, we analyzed the difference of tumor growth rate. RESULTS: The tumor growth of HIF-1alpha siRNA-transfected group was slower than that of the control group both in vitro and in vivo experiment. CONCLUSION: The suppression of HIF-1alpha results in decrease of cell proliferation and increase of chemosensitivity of pancreatic cancer cell line. Therefore, targeting the HIF-1alpha may be useful treatment modality for some pancreatic cancers.


Subject(s)
Animals , Antimetabolites, Antineoplastic/pharmacology , Blotting, Western , Caspase 3/metabolism , Cell Hypoxia , Cell Line, Tumor , Cell Proliferation , Cell Survival/drug effects , Deoxycytidine/analogs & derivatives , Female , Humans , Hypoxia-Inducible Factor 1, alpha Subunit/genetics , Mice , RNA Interference , RNA, Small Interfering/genetics , Random Allocation , Transfection
19.
Article in Korean | WPRIM | ID: wpr-182231

ABSTRACT

BACKGROUND/AIMS: This study was aimed to investigate the expression of matrix metalloproteinase-2 (MMP-2), hypoxia-inducible factor (HIF)-1alpha, and vascular endothelial growth factor (VEGF) in colonic adenoma-carcinoma sequence. METHODS: Thirty-two tissue samples of colon adenoma, 11 of early colon cancer and 36 of advanced colon cancer were collected by colonoscopic biopsy. Normal colonic tissues were also collected from the same subjects. The mRNA expression levels of MMP-2, HIF-1alpha, and VEGF were quantitated using semiquantitative reverse transcription polymerase chain reactions. The protein expressions of activated MMP-2 and HIF-1alpha were examined by gelatin zymography and by Western blot in surgically resected cases, respectively. RESULTS: The expression level of MMP-2 mRNA showed a progressive increase in the advance of the colorectal adenoma-carcinoma sequence (p<0.05). In colon cancer tissues, the expression level of MMP-2 mRNA showed an increasing trend according to differentiation, lymphatic invasion and Dukes' stage (p<0.05). The protein expression of activated MMP-2 was observed in 10 of 11 (91%) cases of cancer tissues. The mRNA expression levels of HIF-1alpha and VEGF were greater in tissues of early and advanced colon cancer compared with colon adenoma (p<0.05; p<0.001). The protein expression of HIF-1alpha was observed in 9 of 11 (82%) cases of cancer tissues. The mRNA expression level of HIF-1alpha showed a positive correlation with MMP-2 and VEGF, respectively (r=0.52, p<0.001; r=0.76, p<0.001). CONCLUSIONS: MMP-2, HIF-1alpha, and VEGF may be useful in detecting early carcinogenesis and progression of colon cancer.


Subject(s)
Adenoma/metabolism , Colonic Neoplasms/metabolism , Humans , Hypoxia-Inducible Factor 1, alpha Subunit/genetics , Matrix Metalloproteinase 2/genetics , Neoplasm Staging , RNA, Messenger/metabolism , Regression Analysis , Retrospective Studies , Vascular Endothelial Growth Factor A/genetics
20.
Article in English | WPRIM | ID: wpr-634327

ABSTRACT

Small hairpin RNA (shRNA) was used to silence the HIF1alpha gene in human retinal pigment epithelial cells (RPE) under hypoxia in order to observe the effect of gene silencing on the expression of matrix metalloproteinase tissue inhibitor 1 (TIMP1). By using chemical hypoxic inducer CoCl2, to mimic RPE hypoxic environment, shRNA against the targeting region of HIF1alpha mRNA sequence was synthesized by a method of in vitro transcription, and the HIF1alpha was interfered in RPE cultured under hypoxia (induced by 150 micromol/L CoCl2). RT-PCR was employed to detect the expression of HIF1alpha and TIMP1. The expression levels of HIF1alpha and TIMP1 were measured by using Western blotting. The results showed that after the RPE were transfected with specific shRNA against HIF1alpha mRNA, RT-PCR revealed that under hypoxia, the efficacy of HIF1alpha gene silencing in RPE was 83.4%. Western blotting revealed that the expression levels of HIF1alpha protein was dramatically dropped. In addition. RT-PCR results demonstrated that the expression of TIMP1 mRNA was decreased by 28.9%, and the expression levels of TIMP1 protein were also significantly reduced by Western blotting. It was suggested that shRNA targeted against HIF1alpha mRNA could effectively silence the HIF1alpha gene, subsequently effectively inhibit the hypoxia-induced up-regulation of TIMP1.


Subject(s)
Cell Hypoxia , Cells, Cultured , Gene Silencing , Hypoxia-Inducible Factor 1, alpha Subunit/genetics , Pigment Epithelium of Eye/cytology , Pigment Epithelium of Eye/metabolism , RNA, Messenger/biosynthesis , RNA, Messenger/genetics , RNA, Small Interfering/pharmacology , Retina/cytology , Retina/metabolism , Tissue Inhibitor of Metalloproteinase-1/biosynthesis , Tissue Inhibitor of Metalloproteinase-1/genetics
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