Abstract
Abstract: :
Purpose: To determine whether the prosaposin gene is down regulated following AION. Prosaposin (PSAP), (also known as Sulfated Glycoprotein 1 and Sphingolipid Activator Protein), is a ubiquitous 70 kDa polypeptide, with multiple roles including synthesis and hydrolysis of glycosphingolipids and glycosphingolipid transport. A significant portion of PSAP is associated with neuron plasma membrane gangliosides, where it has been shown to have neurotrophic, myelinotrophic, neuroprotective and reparative effects. Methods: Initial comparison of the pattern of rat retinal gene expression in control vs. rodent anterior schemic optic neuropathy (rAION) affected retinae, using microarray analysis showed PSAP to be down-regulated during rAION. Using real time RT-PCR (RQ-PCR), PSAP mRNA levels were quantified at 0, 1, 3 and 7 days after initiation of rAION, and compared to the contralateral (control) eye. Total RNA was isolated from retinal tissues using the Qiaprep system (Qiagen; CA). We generated exon-exon sequence specific primers for the rat prosaposin gene. RQ-PCR was performed using SyberGreen (Molecular Probes), and a cyclophilin control primer set. Results: The prosaposin primers generated a unique product with retinal cDNA. Preliminary results suggest that prosaposin mRNA is apparently down-regulated following rAION induction, compared to the untreated (control) eye. Conclusions: The prosaposin gene may be down-regulated following rAION. If prosaposin has retinal neuroprotective properties, this would suggest that the rAION-induced loss of prosaposin may contribute to retinal ganglion cell death.
Keywords: neuroprotection • neuro-ophthalmology: optic nerve • ischemia