(747c) Protease-Activatable Viruses for Cardiovascular Disease Therapy

Cardiovascular disease (CVD) is the leading cause of death around the globe today. Gene therapy is an emerging technology that may be used to treat and cure a wide range of pathologies, including CVD. However, a major issue most researchers face is targeting specificity of gene vector delivery. One hallmark of cardiovascular disease (as well as most human cancers and neurological disorders) is increased protease activity at the affected site. In particular, matrix metalloproteinase-9 (MMP-9) plays a major role in the progression of CVD. Our lab has recently engineered a protease-activatable virus (PAV) based on adeno-associated virus serotype-9 (AAV9) that delivers genetic cargo to diseased cells only upon MMP-9 proteolysis. Briefly, a negatively charged tetra-aspartic acid (D₄) peptide “lock” was inserted throughout the virus protein capsid to prevent the virus’ interactions with its primary cell receptor, galactose. This peptide lock is flanked by two protease-cleavable peptide sequences, which, upon MMP-9 proteolysis, release the D₄ lock and allow subsequent cell binding and internalization of the virus. A major advantage of our approach compared to other targeting approaches, such as targeting peptide insertion, is several diseased cells lack specific receptors that identify them as unique. Instead, PAVs recognize the diseased, MMP-rich tissue microenvironment and deliver genetic cargo only to areas that require therapy. We have already created and characterized over a dozen PAV variants that display varying specificity and kinetic activation for MMP-9. Our goal is to develop specialized PAVs that recognize the specific biomolecular protease signatures of CVD for targeted therapeutic gene delivery to the myocardium.