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This Article Full Text Full Text (PDF) All Versions of this Article: 296/3/L534    most recent 90505.2008v1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Kurtagic, E. Articles by Nugent, M. A. Search for Related Content PubMed PubMed Citation Articles by Kurtagic, E. Articles by Nugent, M. A.

Neutrophil elastase cleaves VEGF to generate a VEGF fragment with altered activity

Departments of ¹Biochemistry and ²Ophthalmology, Boston University School of Medicine and ³Department of Biomedical Engineering, Boston University, Boston, Massachusetts

Submitted 23 September 2008 ; accepted in final form 5 January 2009

Excessive neutrophil elastase (NE) activity and altered vascular endothelial growth factor (VEGF) signaling have independently been implicated in the development and progression of pulmonary emphysema. In the present study, we investigated the potential link between NE and VEGF. We noted that VEGF₁₆₅ is a substrate for NE. Digestion of purified VEGF₁₆₅ with NE generated a partially degraded disulfide-linked fragment of VEGF. Mass spectrometric analysis revealed that NE likely cleaves VEGF₁₆₅ at both the NH₂ and COOH termini to produce VEGF fragment chains 5 kDa reduced in size. NE treatment of VEGF-laden endothelial cell cultures and smooth muscle cells endogenously expressing VEGF generated VEGF fragments similar to those observed with purified VEGF₁₆₅. NE-generated VEGF fragment showed significantly reduced binding to VEGF receptor 2 and heparin yet retained the ability to bind to VEGF receptor 1. Interestingly, VEGF fragment showed altered signaling in pulmonary artery endothelial cells compared with intact VEGF₁₆₅. Specifically, treatment with VEGF fragment did not activate extracellular-regulated kinases 1 and 2 (ERK1/2), yet resulted in enhanced activation of protein kinase B (Akt). Treatment of monocyte/macrophage RAW 264.7 cells with VEGF fragment, on the other hand, led to both Akt and ERK1/2 activation, increased VEGFR1 expression, and stimulated chemotaxis. These findings suggest that the tissue response to NE-mediated injury might involve the generation of diffusible VEGF fragments that stimulate inflammatory cell recruitment and activation via VEGF receptor 1.

lung injury; proteases; extracellular matrix; vascular endothelial growth factor receptors; heparin binding