1. Combined VEGF/PDGF inhibition using axitinib induces αSMA expression and a pro-fibrotic phenotype in human pericytes.
- Author
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Siedlecki, Jakob, Asani, Ben, Wertheimer, Christian, Hillenmayer, Anna, Ohlmann, Andreas, Priglinger, Claudia, Priglinger, Siegfried, Wolf, Armin, and Eibl-Lindner, Kirsten
- Subjects
VASCULAR endothelial growth factors ,PROTEIN-tyrosine kinase inhibitors ,PHENOTYPES ,PERICYTES ,NEOVASCULARIZATION ,RETINAL degeneration ,PHALLOIDINE - Abstract
Purpose: Large trials on anti-VEGF/PDGF (vascular endothelial/platelet-derived growth factor) combination therapy have been established to improve management of neovascular activity in age-related macular degeneration. Targeting pericytes, PDGF is thought to induce vessel regression and reduce fibrovascular scarring. The fate of pericytes exposed to anti-VEGF/PDGF combination therapy is not clear. Therefore, this study was designed to study the influence of anti-VEGF/PDGF on pericyte phenotype and cellular behavior.Methods: Human pericytes from placenta (hPC-PL) were treated with axitinib, a tyrosine kinase inhibitor targeting VEGFR1-3 and PDGFR. Toxic effects were excluded using live/dead staining. Phenotypic changes were evaluated using phalloidin staining for actin cytoskeleton and the expression of stress fibers. MRNA and protein expression levels of α-smooth muscle actin (αSMA) as a marker of proto-myofibroblastic transition were evaluated with real-time PCR and Western blotting. Influences of fibrotic cellular mechanisms were evaluated with a scratch wound migration and a collagen gel contraction assay.Results: Treatment with 0.5, 1, and 2.5 μg/ml axitinib strongly induced a proto-myofibroblast-like actin cytoskeleton with a marked increase in stress fibers. Quantitative real-time PCR and Western blotting revealed these changes to be linked to dose-dependent increases in αSMA mRNA and protein expression. However, fibrotic cellular mechanisms were significantly reduced in the presence of axitinib (scratch wound closure: up to − 78.4%, collagen gel contraction: up to − 37.4%).Conclusions: Combined anti-VEGF/PDGF inhibition seems to induce a proto-myofibroblast-like phenotype in human pericytes in vitro, but reduce profibrotic cellular mechanisms due to prolonged anti-PDGF inhibition. [ABSTRACT FROM AUTHOR]
- Published
- 2018
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