Induction of vitronectin and integrin αv in the retinaafter optic nerve injury

[摘要] Purpose: Vitronectin is a secreted glycoprotein present in bloodplasma and is present in the extracellular matrix of many tissues. Itwas found in the retinal cDNA library that contains genes whoseexpression is upregulated after optic nerve injury in a previous study.The purpose of this study was to assess the temporal and spatial changesin expression of vitronectin and integrin αv in the retinafollowing optic nerve injury.Methods: Adult Balb/c mice underwent crush of the optic nerve in oneeye only. RT-PCR was used to determine the temporal expression ofvitronectin mRNA in the retina after injury. In addition, expression atthe protein level in the retina and the optic nerve of vitronectin andits major receptor subunit, integrin αv, was analyzed byimmunohistochemistry.Results: Upregulation of vitronectin mRNA in the retina was detectedat one day after injury, peaking at three days, and maintained up to oneweek. An elevated expression of vitronectin protein was also observed inthe inner retina, optic nerve head, and the optic nerve after nervecrush. In the inner retina, the increased expression of vitronectin wasfound in retinal ganglion cells (RGCs) and its surrounding extracellularmatrix. Expression of integrin αv was also increased in the RGClayer and in the glial cells of the nerve head and the crush site.Conclusions: As vitronectin is an extracellular protein that cansupport cell attachment and promote neurite extension, elevatedexpression of vitronectin and its receptor may facilitate axonalregeneration following injury. We propose that treatment sustainingsecretion of endogenous vitronectin or direct application of exogenousvitronectin may be a method to augment regeneration of the severed opticaxons.

[学科分类] 生物化学/生物物理