Effects of Lentivirus-Mediated C3 Expression on Trabecular Meshwork Cells and Intraocular Pressure

PURPOSE: We evaluated the effects of lentivirus-mediated exoenzyme C3 transferase (C3) expression on cultured primary human trabecular meshwork (HTM) cells in vitro, and on rat intraocular pressure (IOP). METHODS: HTM cells were cultured and treated with lentivirus vectors expressing either green fluorescent protein (GFP) only (LV-GFP) or GFP and C3 together (LV-C3-GFP). Changes in cell morphology and actin stress fibers were assessed. The vectors were also injected into the anterior chamber of rats, and GFP expression was visualized by a Micron III Retinal Imaging Microscope in vivo and a fluorescence microscope ex vivo. Changes in rat IOP were monitored by using a rebound tonometer and the eyes were evaluated by slit lamp. RESULTS: LV-mediated C3 expression induced morphologic changes in HTM cells. The cells became retracted and rounded. GFP expression in the anterior chamber angle of rats was observed in vivo from 8 days to 48 days after injection of LV-C3-GFP or LV-GFP. IOP was significantly decreased in the LV-C3-GFP group starting 3 days post injection, and lasting for at least 40 days, when compared to either the contralateral control eyes (the LV-GFP group) or the ipsilateral baseline before injection (P < 0.05). No obvious inflammatory signs were observed in either the LV-C3-GFP or LV-GFP groups. CONCLUSIONS: LV-mediated C3 expression induced changes in morphology of cultured HTM cells. Intracameral injection of LV-C3-GFP lowered rat IOP for at least 40 days. No significant inflammatory reactions were observed in either the LV-C3-GFP or LV-GFP groups. This study supports the possible use of C3 gene therapy for the treatment of glaucoma.