Detection and Cellular Localization of Heparin-Binding Epidermal Growth Factor-like Growth Factor mRNA and Protein in Human Atherosclerotic Tissue
Heparin-binding epidermal growth factor-like growth factor (HB-EGF) is a member of the epidermal growth factor family which binds to and activates the epidermal growth factor (EGF) receptor. HB-EGF mRNA is expressed by monocytes and vascular smooth muscle cells (VSMC) in culture, and has been shown to be a potent VSMC mitogen in vitro. The aim of this study was to screen normal and human atherosclerotic arteries and SMC cultured from these arteries for expression of HB-EGF, and to determine its cellular localization in human lesions. Using the highly sensitive technique of reverse transcription polymerase chain reaction (RT-PCR), we screened biopsies taken from normal human vessel walls and atherosclerotic tissue, for expression of HB-EGF mRNA. Northern blotting and RT-PCR were employed to determine levels of HB-EGF gene expression in SMC, cultured from normal and atherosclerotic arteries. Cellular localization of mRNA and protein, within human atherosclerotic plaques, was assessed using in situ hybridization with 35S labelled riboprobes, and immunohistochemistry with polyclonal antibodies specific for human HB-EGF. HB-EGF mRNA was found to be expressed in human atherosclerotic lesions and in VSMC cultured from these lesions. Expression of HB-EGF could not be detected in quiescent aortic VSMC using Northern blotting, but was highly up-regulated in these cells after treatment with basic fibroblast growth factor (bFGF) for 24 h. Although HB-EGF mRNA was detected in all vascular tissue examined using RT-PCR, in situ hybridization and immunohistochemistry revealed expression of HB-EGF in small portions of diseased arteries only. Immunohistochemistry showed strong staining for macrophages in all areas of HB-EGF expression. No association of HB-EGF with SMC was observed in any of the specimens examined. In conclusion, HB-EGF, a potent mitogen for VSMC, is expressed by macrophages in human.
Available from: Shahida Shafi
- "EGFR is activated by binding to a number of peptide growth and differentiating factors, including epidermal growth factor (EGF), heparin-binding EGF (HB-EGF), transforming growth factor-a (TGF-a), amphiregulin (AR) and epiregulin (EPR), which are released from platelets, SMCs, endothelial cells and macrophages (Dreux et al. 2006). Several of these ligands have been identified on monocytes and in macrophage rich-areas of human aortic and coronary atherosclerotic lesions (Mograbi et al. 1997; Reape et al. 1997; Tamura et al. 2001; Panutsopulos et al. 2005). EGF and HB-EGF have been shown to stimulate macrophages and smooth muscle cells proliferation and migration in vitro (Higashiyama et al. 1993; Lamb et al. 2004). "
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ABSTRACT: Monocyte recruitment and their differentiation into macrophages are both early events in native and accelerated atherosclerosis that follows angioplasty. We have investigated the putative functional role of the epidermal growth factor receptor (EGFR) present on rabbit monocytes/macrophages. The impact of periadventitial delivery of an EGFR-specific, blocking monoclonal antibody (ICR62, which inhibits EGF-binding to its receptor) was investigated in a rabbit model of accelerated atherosclerosis induced by a combination of carotid injury and 4 weeks of a 2% cholesterol-diet. Two weeks after the initiation of the diet, a balloon-catheter angioplasty of the left common carotid artery was performed and a collar placed around the injured carotid artery immediately, for the delivery of ICR62 antibody, isotype-matched antibody or saline control. Monocyte/macrophage accumulation, cell proliferation and neointimal thickening were determined 2 weeks after the delivery of the antibodies. The function of the EGFR on rabbit monocytes was also investigated in vitro, using chemotaxis assays. Treatment with ICR62 was associated with a significant reduction in macrophage accumulation and neointimal thickening and a 76% reduction in neointimal area of the vessel wall compared with controls. In vitro ICR62 inhibited macrophage and smooth muscle cell migration towards EGFR ligands including EGF and HB-EGF. These findings suggest that EGFR ligation may be important in the development of early atherosclerotic lesions following balloon-catheter angioplasty, and periadventitial delivery may provide a feasible approach for administration of the inhibitors of EGFR-binding such as ICR62.
Available from: Louise Showe
- "HBEGF has been shown to induce proliferation of smooth-muscle cells  ; b-thromboglobulin (part of the upregulated PPBP) is chemotactic for fibroblasts . HBEGF has also been detected in macrophages in AT tissues  and in C. pneumoniae–infected endothelial cells . We also found that important members of the coagulation cascade, coagulation factor V and plasminogen activator urokinase , were up-regulated after C. pneumoniae infection, indicating that the local coagulation cascade could also be influenced by C. pneumoniae–infected monocytes. "
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ABSTRACT: The effect of infection with Chlamydia pneumoniae on host messenger RNA expression in human monocytic cells with complement DNA microarrays was studied. The data chronicle
a cascade of transcriptional events affecting 128 genes, many of which have not previously been reported to be affected by
C. pneumoniae infection. Down-regulated genes are primarily associated with RNA and DNA metabolism, chromosomal stability, and cell-cycle
regulation. Up-regulated messages include those for a variety of genes with important proinflammatory functions. Many of the
up-regulated genes—including the hyaluron receptor CD44, vasoconstrictor endothelin-1, smooth muscle growth factor heparin-binding
EGF-like growth factor, and fatty acid binding protein–4—had been previously described as linked to the development of atherosclerosis
and other chronic inflammatory diseases. C. pneumoniae–infected monocytes can contribute to the development and progression of diseases for which acute or chronic inflammation
has been shown to be important, such as atherosclerosis
Available from: bioscience.org
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ABSTRACT: Heparin-binding EGF-like growth factor (HB-EGF) is a 22 kDa, O-glycosylated protein that is mitogenic for fibroblasts, smooth muscle cells (SMC) and epithelial cells. This review describes the primary structure of HB-EGF, as well as its processing. The structure of the mouse and human HB-EGF genes is also discussed. Finally, this review summarizes HB-EGF expression patterns, receptor-mediated signaling, and role in several important biological systems.
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