Effect of Plant-derived Angiogenin Fusion Protein's on Matrix Metalloproteinase-1 and Alpha Smooth Muscle Actin in Trabecular Meshwork Cells

Purpose: Benzalkonium chloride (BAK), commonly used in glaucoma treatment, is an eye drop preservative with dose-dependent toxicity. Previous studies have observed the multi-functional benefits of angiogenin (ANG) against glaucoma. In our study, we developed a plant-derived ANG fusion protein and evaluated its effect on the trabecular meshwork (TM) damage induced by BAK in human TM cell lines. Methods: Plant-derived ANG (ANG-FcK) was synthesized by fusing immunoglobulin G's Fc region and KDEL to conventional recombinant human ANG (Rh-ANG) purified from transgenic tobacco plants. Expression patterns of matrix metalloproteinase-1 (MMP-1) and alpha smooth muscle actin (a-SMA) in human TM cell lines were evaluated by immunocytochemical analysis and at the levels of protein and mRNA. We used BAK to look for toxic changes, and ANG-FcK and Rh-ANG for the protective effects. Results: In human TM cell lines, BAK induced more prominent expressions of MMP-1 and -SMA. ANG co-treatment augmented the MMP-1 expression, however lessened the -SMA expression. Expression were showed similar pattern between the ANG-FcK and Rh-ANG. Conclusions: Plant-derived ANG-FcK showed similar effects as Rh-ANG in the BAK-induced degenerative TM cell lines, and that effect might be related to the anti-fibrosis mechanism, suggesting that plant-derived ANG-FcK could be a promising glaucoma treatment.