Abstract
Purpose :
The regulative process of corneal avascularity is not completely understood, in particular after corneal transplantation the progressive neoangiogenesis of the cornea leads to loss of the existing immune privilege and increases the risk of graft rejection. MicroRNA (miR) gene therapies are of particular interest for complex processes such as fibrosis and angiogenesis. The role of miRs in corneal vascularization remains unclear. Vascularization of the cornea leads to loss of transparency, increased corneal astigmatism and causes therefore visual reduction. This study focusses on the role of miR27a/b and its target Semphorin6A in vascularisation of human cornea.
Methods :
Levels of miR27a/b were measured by Real-Time PCR in patients tear samples. In vitro proliferation and wound healing assays were performed with Human Umbilical Vein Endothelial Cells (HUVEC) and Human Cornea Endothelial Cells (HCEC) upon transfection with miRNA mimics or the stimulation with Semaphorin6A. Activation of the signalling pathways FAK (focal adhesion kinase), ERK1/2 (extracellular signal–regulated kinase) and AKT (protein kinase B) were investigated by flow cytometric analysis upon Semaphorin6A stimulation.
Results :
Levels of miR27a/b were shown to be significantly reduced in patients with early stages of vascularization (p<0.001) in comparison to patients suffering of other diseases. In vitro, the inhibition of the miR27a/b resulted in increased cell proliferation whereas miR27a/b mimicking led to a decrease in cell growth. Wound healing and proliferation assays have shown that Semaphorin6A induces proliferation by up to 1.21-fold. Semaphorin6A showed to activate the ERK1/2 signaling pathway by up to 1.24-fold and the AKT signaling pathway by up to 1.33-fold.
Conclusions :
The mimic of miR27a/b may be used as a therapeutic agent in early corneal-vascularization-stages by inhibiting the angiogenesis. This study may be the basis for the development of novel therapeutic options to prevent visual impairment due to excessive cornea vascularization.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.