Epiregulin is more potent than EGF or TGFα in promoting in vitro wound closure due to enhanced ERK/MAPK activation
✍ Scribed by Bradley K. Draper; Toshi Komurasaki; Mari K. Davidson; Lillian B. Nanney
- Publisher
- John Wiley and Sons
- Year
- 2003
- Tongue
- English
- Weight
- 254 KB
- Volume
- 89
- Category
- Article
- ISSN
- 0730-2312
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✦ Synopsis
Abstract
Epiregulin (EPR) is a broad specificity EGF family member that activates ErbB1 and ErbB4 homodimers and all possible heterodimeric ErbB complexes. We have previously shown that topical EPR enhances the repair of murine excisional wounds. The purpose of this study was to determine whether EPR was more effective than EGF or TGFα in promoting in vitro wound closure and to compare the EPR induced signal transduction pathways with those activated by EGF and TGFα. Normal human epidermal keratinocytes or A431 cells were scratch wounded and treated for 24 h with varying doses of EPR, EGF or TGFα. Five‐fold lower doses of EPR were significantly better than EGF or TGFα in stimulating in vitro wound closure. Mitomycin‐c reduced EPR induced wound closure by 59%, versus a 9% and 25% decrease in EGF and TGFα induced closure. The ERK/MAPK inhibitor PD‐98059 decreased EPR induced wound closure by 88%. By contrast, the PLC inhibitor U‐73122, only reduced the EPR induced response by 21%. Immunoblot analysis revealed that 2 nM EPR stimulated a six‐fold increase in p‐ERK1/2, whereas 10 nM EGF or TGFα stimulated only a 3‐ and 2.5‐fold increase in p‐ERK1/2. When compared with EGF or TGFα, EPR is a more potent and more effective inducer of in vitro wound closure due to its ability to promote significantly greater ERK/MAPK activation. © 2003 Wiley‐Liss, Inc.