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Updated: Aug 11, 2026
Induction and Testing of Hypoxia in Cell Culture
Published on: August 12, 2011
Hypoxia-induced gene expression in human macrophages: implications for ischemic tissues and hypoxia-regulated gene
Bernard Burke1, Athina Giannoudis, Kevin P Corke
1Tumor Targeting Group, Section of Oncology and Pathology, Division of Genomic Medicine, University of Sheffield Medical School, Sheffield, United Kingdom.
Abstract:
Macrophages accumulate in ischemic areas of such pathological tissues as solid tumors, atherosclerotic plaques and arthritic joints. Studies have suggested that hypoxia alters the phenotype of macrophages in a way that promotes these lesions. However, the genes up-regulated by macrophages in such hypoxic tissues are poorly characterized. Here, we have used cDNA array hybridization to investigate the effects of hypoxia on the mRNAs of 1185 genes in primary human monocyte-derived macrophages. As shown previously in other cell types, mRNA levels for vascular endothelial growth factor (VEGF) and glucose transporter 1 (GLUT-1) were up-regulated by hypoxia. However, the mRNAs of other genes were also up-regulated including matrix metalloproteinase-7 (MMP-7), neuromedin B receptor, and the DNA-binding protein inhibitor, Id2. The promoters of GLUT-1 and MMP-7 confer hypoxic inducibility on a reporter gene in RAW 264.7 macrophages, indicating that the hypoxic up-regulation of these mRNAs may occur, at least in part, at the transcriptional level. GLUT-1 and MMP-7 mRNA were also shown to be up-regulated in hypoxic macrophages in vitro by real-time RT-PCR, and these proteins were elevated in hypoxic macrophages in vitro and in hypoxic areas of human breast tumors. The hypoxia up-regulated genes identified could be important for the survival and functioning of macrophages in hypoxic diseased tissues, and their promoters could prove useful in macrophage-delivered gene therapy.
Insights
Hypoxia up-regulates specific genes in macrophages, including vascular endothelial growth factor (VEGF) and glucose transporter 1 (GLUT-1), which may aid their survival in diseased tissues. These findings offer potential targets for gene therapy in conditions like cancer and atherosclerosis.
Area of Science:
- Cell Biology
- Molecular Biology
- Pathophysiology
Background:
- Macrophages are crucial immune cells that infiltrate pathological tissues, including tumors and atherosclerotic plaques.
- Tissue hypoxia (low oxygen) is a hallmark of these conditions and is known to influence macrophage behavior.
- The specific genes regulated by macrophages under hypoxic conditions remain largely uncharacterized.
Purpose of the Study:
- To comprehensively investigate the gene expression profile of human macrophages under hypoxic conditions.
- To identify novel hypoxia-up-regulated genes in macrophages relevant to pathological processes.
- To explore the potential transcriptional regulation and therapeutic implications of these identified genes.
Main Methods:
- Utilized cDNA array hybridization to analyze the mRNA expression of 1185 genes in primary human monocyte-derived macrophages exposed to hypoxia.
- Validated the hypoxic inducibility of specific genes (GLUT-1, MMP-7) using reporter gene assays in RAW 264.7 macrophages.
- Quantified mRNA and protein levels of key genes in vitro and in vivo using real-time RT-PCR and analysis of human breast tumor samples.
Main Results:
- Hypoxia significantly up-regulated mRNA levels for known genes like vascular endothelial growth factor (VEGF) and glucose transporter 1 (GLUT-1).
- Identified novel hypoxia-induced genes in macrophages, including matrix metalloproteinase-7 (MMP-7), neuromedin B receptor, and Id2.
- Demonstrated that hypoxic up-regulation of GLUT-1 and MMP-7 occurs, at least partly, at the transcriptional level.
- Confirmed elevated GLUT-1 and MMP-7 protein levels in hypoxic macrophages and in human breast tumors.
Conclusions:
- Hypoxia induces a distinct set of genes in macrophages, contributing to their survival and function in pathological microenvironments.
- The identified hypoxia-up-regulated genes, such as GLUT-1 and MMP-7, are potential therapeutic targets.
- The promoters of these genes could be valuable tools for macrophage-targeted gene therapy in diseases characterized by hypoxia.
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