Detection and Cellular Localization of Heparin-Binding Epidermal Growth Factor-like Growth Factor mRNA and Protein in Human Atherosclerotic Tissue

Department of Medicine, U.M.D.S., St Thomas' Hospital, London, UK.
Journal of Molecular and Cellular Cardiology (Impact Factor: 4.66). 07/1997; 29(6):1639-48. DOI: 10.1006/jmcc.1997.0399
Source: PubMed


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.

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    • "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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