Anti-Angiogenic Properties Of Opticin

Angiogenesis plays a key role in ocular development and disease. Opticin is an extracellular matrix small leucine-rich repeat glycoprotein which was first isolated from vitreous humour of the eye. As it is highly expressed in the eye throughout life, we hypothesised that it may contribute towards the angiogenic process. The effect of opticin on FGF-2-stimulated angiogenesis was determined using assays for monolayer wound recovery and boyden chamber (migration), tube-like structure formation and invasion in matrigel or collagen gel, and examination of protein phosphorylation using Kinexus Western arrays (Bioinformatics, Canada). The presence of opticin decreased cell migration (31%, p< 0.005), tube like structure formation (37%, p<0.001) and cell invasion (45%, p<0.001). Opticin also significantly decreased the development of blood vessel formation in the chick chorioallantoic membrane assay. Opticin decreased FGF-2-induced phosphorylation of MEK1/2 (MAPK kinase), JNK and p38 (MAPK). A decrease of MAPKs phosphorylation is known to play crucial roles in cell migration and tubular morphogenesis. Therefore, opticin maybe an inhibitor of vascular ingression into the vitreous humour.