ErbB2 activity is required for airway epithelial repair following neutrophil elastase exposure.

Published

Journal Article

In cystic fibrosis and chronic bronchitis, airways are chronically injured by exposure to neutrophil elastase (NE). We sought to identify factors required for epithelial repair following NE exposure. Normal human bronchial epithelial cells were treated with NE (50 nM, 22 h) or control vehicle. Following NE treatment, we found a marked and sustained decrease in epithelial proliferation as detected by Ki67 immunostaining. 3H-thymidine incorporation was also initially depressed but increased over 72 h in NE-treated cells, which suggests that DNA synthesis constitutes an early repair process following NE exposure. We hypothesized that ErbB2 receptor tyrosine kinase, a regulator of cancer cell proliferation, was required for epithelial DNA synthesis following NE exposure. Immediately following NE treatment, by flow cytometry analysis, we found a decrease in ErbB2 surface expression. Protein levels of the full-length 185 kD ErbB2 receptor significantly decreased following NE treatment and smaller ErbB2-positive bands, ranging in size from 23 to 40 kD, appeared, which suggests that NE caused ErbB2 degradation. By real-time RT-PCR analysis, we found no change in ErbB2 mRNA expression following NE treatment, which suggests that changes in ErbB2 protein levels were regulated at the post-translational level. Following NE treatment, full-length 185 kD ErbB2 levels increased to pretreatment levels, correlating with the increase in thymidine incorporation during the same time period. Importantly, inhibition of ErbB2 activity with AG825 (5 microM) or Herceptin (3.1 microM), an ErbB2-neutralizing antibody, blocked thymidine incorporation only in NE-treated cells. These results suggest ErbB2 is a critical factor for epithelial recovery following NE exposure.

Full Text

Duke Authors

Cited Authors

  • Fischer, BM; Cuellar, JG; Byrd, AS; Rice, AB; Bonner, JC; Martin, LD; Voynow, JA

Published Date

  • August 2005

Published In

Volume / Issue

  • 19 / 10

Start / End Page

  • 1374 - 1376

PubMed ID

  • 15923396

Pubmed Central ID

  • 15923396

Electronic International Standard Serial Number (EISSN)

  • 1530-6860

International Standard Serial Number (ISSN)

  • 0892-6638

Digital Object Identifier (DOI)

  • 10.1096/fj.04-2675fje

Language

  • eng