[Viral vectors for gene delivery to corneal endothelial cells]

Corneal endothelium is an interesting target for in vitro gene transfer strategies as it is readily accessible thanks to its anatomic structure as a monolayer and its direct contact to culture medium. Whereas the use of adenoviruses as viral vectors (carriers) to endothelial cells (EC) has been described as problematic as to its immunogenicity, lentiviruses and adeno-associated viruses (AAV) are potent vectors for the transfer of genetic DNA into EC. Lentiviral vectors, developed on the basis of HI-viruses, can integrate the transferred gene into the host DNA and thus lead to a permanent protein expression. Evaluating apathogen alternatives to lentiviral vectors for humans, we herein compared non-integrating AAV to lentiviral gene transfer.

A comparison was made of the kinetics of expression of a green fluorescent protein after transduction using a lentiviral vector and AAV 2 / 2 in a murine EC line, human EC line and human primary cells (flow cytometry). A proof of principle experiment was conducted to demonstrate the function after lentiviral gene transfer of the anti-apoptotic gene Bcl-xL.

The kinetics of protein expression after transduction of EC using a lentiviral or an AAV vector show fundamental differences. Contrary to gene transfer using AAV, a high expression of the reporter protein was readily detectable only hours after transduction using the lentiral vector. In addition, we could demonstrate distinct differences in protein expression characteristics between human and murine EC as well as human EC line and primary human EC. Function could be demonstrated by showing a significant reduction in apoptosis in both murine and human EC.

AAV vectors are an alternative to lentiviral vectors for gene transfer to corneal EC. Given a cultivation time of donor corneas of up to 4 weeks before transplantation, translation to eye banking, e. g., to decrease apoptosis in corneal allografts, is conceivable.