Effect of VEGF-A on expression of profibrotic growth factor and extracellular matrix genes in the retina.
OBJECTIVE
Vascular endothelial growth factor-A (VEGF) causes increased vascular permeability and leukocyte adhesion in preclinical diabetic retinopathy (PCDR). Another hallmark of PCDR is thickening of the capillary basement membrane (BM). Recently, VEGF has been shown to induce expression of profibrotic genes such as transforming growth factor (TGF)-beta1 and connective tissue growth factor (CTGF or CCN2) in cultured endothelial cells. Moreover, neutralization of VEGF prevented BM thickening in diabetic mice in vivo. The authors hypothesize that VEGF directly contributes to BM thickening in the diabetic retina by inducing expression of profibrotic growth factors and extracellular matrix (ECM) components.


METHODS
Transcription and protein levels of ECM-related genes were evaluated in the rat retina after intravitreal VEGF injection by real-time quantitative PCR, Western blot analysis, and immunohistochemistry. In addition, expression profiles of the same genes in response to VEGF stimulation were investigated in bovine retinal vascular cells in vitro.


RESULTS
Intravitreal VEGF injection induced retinal transcription of CYR61 (CCN1), CTGF, TGF-beta1, tissue inhibitor of metalloproteases (TIMP)-1 and fibronectin, and protein expression of CYR61, CTGF, TGF-beta1 and fibronectin. In bovine retinal endothelial cells and pericytes stimulated by VEGF in vitro, gene expression profiles were similar to those in the intact retina in vivo.


CONCLUSIONS
VEGF induces profibrotic growth factors and extracellular matrix genes in the retina in vivo, as well as in cultured retinal vascular cells in vitro. The current findings have relevance for understanding the pathogenesis of preclinical DR, where early upregulation of VEGF may cause BM thickening by induction of ECM-related genes.
Kuiper
Esther J
EJ
Ocular Angiogenesis Group, Department of Ophthalmology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands.
Hughes
John M
JM
Van Geest
Rob J
RJ
Vogels
Ilse M C
IM
Goldschmeding
Roel
R
Van Noorden
Cornelis J F
CJ
Schlingemann
Reinier O
RO
Klaassen
Ingeborg
I
D000818:Animals; D015153:Blotting, Western; D055513:Connective Tissue Growth Factor; D055515:Cysteine-Rich Protein 61; D004730:Endothelium, Vascular / Q000378:metabolism; D016326:Extracellular Matrix Proteins / Q000235:genetics*; D005353:Fibronectins / Q000235:genetics; D005786:Gene Expression Regulation / Q000187:drug effects*; D017874:Immediate-Early Proteins / Q000235:genetics* / Q000378:metabolism; D007124:Immunoenzyme Techniques; D036341:Intercellular Signaling Peptides and Proteins / Q000235:genetics* / Q000378:metabolism; D020286:Pericytes / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D012160:Retina / Q000187:drug effects / Q000378:metabolism*; D012171:Retinal Vessels / Q000166:cytology; D019715:Tissue Inhibitor of Metalloproteinase-1 / Q000235:genetics; D053773:Transforming Growth Factor beta1 / Q000235:genetics* / Q000378:metabolism; D042461:Vascular Endothelial Growth Factor A / Q000494:pharmacology*
C501849:CCN1 protein, rat; C526318:CCN2 protein, mouse; C526316:CCN2 protein, rat; D055515:Cysteine-Rich Protein 61; D016326:Extracellular Matrix Proteins; D005353:Fibronectins; D017874:Immediate-Early Proteins; D036341:Intercellular Signaling Peptides and Proteins; D012333:RNA, Messenger; D019715:Tissue Inhibitor of Metalloproteinase-1; D053773:Transforming Growth Factor beta1; D042461:Vascular Endothelial Growth Factor A; C467498:vascular endothelial growth factor A, rat; D055513:Connective Tissue Growth Factor