Purchase this article with an account.
A. H. Dahlmann, M. Bailly, P. T. Khaw; Novel PDGF Signalling Pathways Mediating Contraction and Scarring in the Cornea. Invest. Ophthalmol. Vis. Sci. 2007;48(13):1493.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
Our previous work on tissue contraction and scarring demonstrated that fibroblasts generate contractile force by formation and retraction of actomyosin-dependent cellular processes which displace collagen matrix fibres towards the cell. Here we dissect one pathway which is pivotal in corneal scarring and haze formation: the events downstream of the PDGF (platelet derived growth factor) receptor.
We used human corneal fibroblasts (HCF) in monolayer and in standard collagen matrix, and stimulated them with PDGF or fully complemented medium. We acquired live timelapse phase and confocal microscopical images and digital photographs of whole matrix. We used the monolayer assay to dissect the pathway downstream of the PDGF receptor with receptor antibodies, receptor tyrosine kinase and myosin blockers (AG1295, ML9, Y27632, blebbistatin) and transfection with specific plasmids and siRNA (rab5/RNTre/S34N). Then we quantified the effects of these same inhibitors on cell behaviour in 3D collagen and on matrix contraction using the software packages Excel, Openlab, ImageJ, and Metamorph.
PDGF induces a ruffling phenotype in HCFs in monolayers that can be inhibited specifically by blocking the arp2/3-myosin pathways of actin polymerisation or the novel rab5/RNTre pathway. Within a 3D matrix the HCFs respond to PDGF by increasing their dynamic activity, resulting in matrix contraction by 55% in 24 hours. This early contraction phase appears strongly reliant on the specific pathways identified on the monolayers.
This work describes two novel pathways resulting in cell protrusive activity and matrix contraction by HCFs following PDGF stimulation. Specific inhibitors of these pathways are likely candidates to prevent corneal haze formation after surgery, trauma, or inflammation.
This PDF is available to Subscribers Only