Abstract
Purpose: :
In the corneal stroma, the mechanisms by which the fibroblast networks are laying between the stromal lamellae remain unclear. Therefore the role of VEGF receptors in the network formation capacyity of human corneal fibroblast was investigated in vitro.
Methods: :
Corneal fibroblasts, obtained from cornea gifts, were immortalized by the SV40 virus. The presence of VEGFs, FGFs and their receptors was evaluated by genomic profiling of total RNA using microarray analysis with DNA chip of 1300 genes. In parallel, VEGFs and their receptors were also studied by immunocytochemistry and RT–PCR. Additionally, the capacity of corneal fibroblasts, from 35 human corneas, to form network was analyzed on semi solid matrix of MatrigelTM.
Results: :
1) Microarray analysis shows a significant homology between primary cultured human corneal fibroblasts and those immortalized by the SV40 virus. Corneal fibroblasts expressed mRNAs for VEGF–A, VEGF–B and for the receptors VEGF–R1 (flt–1), VEGF–R3 (flt–4); mRNAs for FGF–2, FGF–19 and for their receptors were detected. The presence of VEGF receptors was confirmed by RT–PCR and immunocytochemical analysis using specific antibodies. 2) The corneal fibroblasts from donors can be classified into two groups according to whether they formed a reticulum on MatrigelTM or not.
3) Network–forming corneal fibroblasts expressed flt–1 and flt–4 receptors while non–network–forming fibroblasts expressed only flt–4 receptor. This finding suggests that flt–1 is involved in the formation of corneal network.
Conclusions: :
There are two profiles of corneal fibroblasts according to the donors: the 1st group is characterized by fibroblast reticulogenesis on MatrigelTM; the second one does not form a reticulum under the same conditions. This absence of reticulation seems to be related to a decreased expression of flt–1 (VEGF–R1). This work was partially supported by Rétina France 2005, Paris France.
Keywords: cornea: stroma and keratocytes • gene microarray • gene/expression