Hypoxia-inducible transcription factor-1α promotes hypoxia-induced A549 apoptosis via a mechanism that involves the glycolysis pathway

BACKGROUND: Hypoxia-inducible transcription factor-1α (HIF-1α), which plays an important role in controlling the hypoxia-induced glycolysis pathway, is a "master" gene in the tissue hypoxia response during tumor development. However, its role in the apoptosis of non-small cell lung cancer remains unknown. Here, we have studied the effects of HIF-1α on apoptosis by modulating HIF-1α gene expression in A549 cells through both siRNA knock-down and over-expression. METHODS: A549 cells were transfected with a HIF-1α siRNA plasmid or a HIF-1α expression vector. Transfected cells were exposed to a normoxic or hypoxic environment in the presence or absence of 25 mM HEPES and 2-deoxyglucose (2-DG) (5 mM). The expression of three key genes of the glycolysis pathway, glucose transporter type 1(GLUT1), phosphoglycerate kinase 1(PGK1), and hexokinase 1(HK1), were measured using real-time RT-PCR. Glycolysis was monitored by measuring changes of pH and lactate concentration in the culture medium. Apoptosis was detected by TUNEL assay and flow cytometry. RESULTS: Knocking down expression of HIF-1α inhibited the glycolysis pathway, increased the pH of the culture medium, and protected the cells from hypoxia-induced apoptosis. In contrast, over-expression of HIF-1α accelerated glycolysis in A549 cells, decreased the pH of the culture medium, and enhanced hypoxia-induced apoptosis. These effects of HIF-1α on glycolysis, pH of the medium, and apoptosis were reversed by treatment with the glycolytic inhibitor, 2-DG. Apoptosis induced by HIF-1α over-expression was partially inhibited by increasing the buffering capacity of the culture medium by adding HEPES. CONCLUSION: During hypoxia in A549 cells, HIF-1α promotes activity of the glycolysis pathway and decreases the pH of the culture medium, resulting in increased cellular apoptosis

Hot-Dip Galvanizing Process and the Influence of Metallic Elements on Composite Coatings

The corrosion of steel materials has become a global issue, causing significant socio-economic losses and safety concerns. Hot-dip galvanizing is currently one of the most widely used steel anti-corrosion processes. With the rapid advancement of science and technology and emerging industries, the performance of pure galvanized products struggles to meet the demands of practical applications in various environments. Consequently, researchers have begun introducing various metals into the zinc solution to form high-performance alloy coatings. This article primarily explains the process flow of hot-dip galvanizing and the impact of metal elements such as Al, Mg, Sn, and Bi on the coating, as well as outlining the major issues currently faced by the hot-dip galvanizing process. The objective is to offer a more comprehensive introduction to those new to the field of hot-dip galvanizing and to provide theoretical insights for addressing production issues

Hypoxia-inducible transcription factor-1α promotes hypoxia-induced A549 apoptosis via a mechanism that involves the glycolysis pathway

Abstract Background Hypoxia-inducible transcription factor-1α (HIF-1α), which plays an important role in controlling the hypoxia-induced glycolysis pathway, is a "master" gene in the tissue hypoxia response during tumor development. However, its role in the apoptosis of non-small cell lung cancer remains unknown. Here, we have studied the effects of HIF-1α on apoptosis by modulating HIF-1α gene expression in A549 cells through both siRNA knock-down and over-expression. Methods A549 cells were transfected with a HIF-1α siRNA plasmid or a HIF-1α expression vector. Transfected cells were exposed to a normoxic or hypoxic environment in the presence or absence of 25 mM HEPES and 2-deoxyglucose (2-DG) (5 mM). The expression of three key genes of the glycolysis pathway, glucose transporter type 1(GLUT1), phosphoglycerate kinase 1(PGK1), and hexokinase 1(HK1), were measured using real-time RT-PCR. Glycolysis was monitored by measuring changes of pH and lactate concentration in the culture medium. Apoptosis was detected by TUNEL assay and flow cytometry. Results Knocking down expression of HIF-1α inhibited the glycolysis pathway, increased the pH of the culture medium, and protected the cells from hypoxia-induced apoptosis. In contrast, over-expression of HIF-1α accelerated glycolysis in A549 cells, decreased the pH of the culture medium, and enhanced hypoxia-induced apoptosis. These effects of HIF-1α on glycolysis, pH of the medium, and apoptosis were reversed by treatment with the glycolytic inhibitor, 2-DG. Apoptosis induced by HIF-1α over-expression was partially inhibited by increasing the buffering capacity of the culture medium by adding HEPES. Conclusion During hypoxia in A549 cells, HIF-1α promotes activity of the glycolysis pathway and decreases the pH of the culture medium, resulting in increased cellular apoptosis.</p

Salidroside protects retinal endothelial cells against hydrogen peroxide-induced injury via modulating oxidative status and apoptosis

<div><p>Oxidative stress can cause injury in retinal endothelial cells. Salidroside is a strong antioxidative and cytoprotective supplement in Chinese traditional medicine. In this study, we investigated the effects of salidroside on H₂O₂-induced primary retinal endothelial cells injury. Salidroside decreased H₂O₂-induced cell death, and efficiently suppressed cellular ROS production, malondialdehyde generation, and cell apoptosis induced by H₂O₂ treatment. Salidroside induced the intracellular mRNA expression, protein expression, and enzymatic activities of catalase and Mn-SOD and increased the ratio of Bcl2/Bax. Our results demonstrated that salidroside protected retinal endothelial cells against oxidative injury through increasing the Bcl2/Bax signaling pathway and activation of endogenous antioxidant enzymes. This finding presents salidroside as an attractive agent with potential to attenuate retinopathic diseases.</p></div

Effects of adiponectin polymorphisms on the risk of advanced age-related macular degeneration

<div><p></p><p><i>Objective</i>: To determine the relationships between variants in adiponectin gene (<i>ADIPOQ</i>) with advanced forms of age-related macular degeneration (AMD) susceptibility.</p><p><i>Methods</i>: A total of 189 advanced AMD patients and 168 controls were recruited. Seven tagging single-nucleotide polymorphisms in <i>ADIPOQ</i> were genotyped by the SNaPshot method.</p><p><i>Results</i>: Alleles or genotypes of rs822396 distributed significantly differently in advanced AMD patients and controls. The minor allele G at rs822396 was associated with an increased risk of advanced AMD in a dominant model. Furthermore, haplotype analysis revealed that haplotypes AGGACCT and TGACCCC were significantly increased the advanced AMD susceptibility, whereas haplotypes AGAACGC, TGAACGT and TGACAGC had protective effects.</p><p><i>Conclusion</i>: <i>ADIPOQ</i> genetic variant rs822396 might affect an individual’s susceptibility to AMD, making it efficient genetic biomarkers for early detection of AMD.</p></div