Adeno-Associated Virus Mediated Expression of Bcl-xL Attenuates Apoptosis in Fuchs Endothelial Corneal Dystrophy

Fuchs Endothelial Corneal Dystrophy (FECD) is characterized by progressive corneal endothelial cell loss and the formation of corneal guttae. Currently, there is a global shortage of donor corneas and new strategies are needed to reduce the need for corneal transplantation. While adeno-associated viruses (AAVs) have the capacity to deliver anti-apoptotic genes to human corneal endothelial cells (CECs), this has not been fully explored as a therapeutic strategy for FECD. In this study, we evaluated the transduction efficiency of self-complementary (sc-) and single-stranded (ss-) AAV2 serotypes in human CECs and ex vivo tissues and assessed whether AAV-mediated expression of Bcl-xL could attenuate apoptosis in FECD. Seventeen scAAV2 serotypes were screened for transduction efficiency in normal human CECs via green fluorescent protein (GFP) expression. The top 4 AAV2 serotypes were further evaluated in FECD cell lines, healthy cadaveric donor specimens, and FECD patient specimens. FECD cell lines were transduced with anti-apoptotic ssAAV2/5-Bcl-xL (AAV2/5-CAG-eGFP-P2A-BCLXL) and treated with etoposide to induce apoptosis. We found that scAAV2/5 demonstrated high transduction efficiency across all normal and FECD cell lines and tissues. We observed that ssAAV2/5-mediated expression of Bcl-xL provided significant protection against etoposide-induced apoptosis in FECD CECs (71.68%{+/-}0.69 vs 23.96%{+/-}8.88%, p=0.018). Our findings show that AAVs have the potential for therapeutic gene delivery to the human corneal endothelium, and that targeting the Bcl-xL mediated apoptotic pathway can be further explored as a therapeutic for FECD.