GFP Adeno-Associated Virus ( AAV587MTP )

Adeno-associated virus (AAV) has become the dominant gene transfer vector for striated muscle. However, AAV vectors also exhibit broad tropism after systemic delivery. One of the approaches to target AAV to muscle is to alter its natural interaction with cell receptors and retarget the virus to muscle via different binding ligands. Among the AAV serotypes currently in use, AAV2 is the serotype with the best characterized virus-cell interactions. It is also the best documented AAV vector in preclinical studies and clinical trials over the past 20 years. Therefore, AAV2 can serve as a good candidate for de-targeting and re-targeting genetic engineering. To enhance the muscle tropism of AAV vectors by ligand-directed gene delivery, the AAV2 capsid surface was genetically engineered with the muscle-targeting peptide MTP, a small 7-mer peptide ASSLNIA. In cultured cells in vitro, the insertion of MTP not only renders AAV2 infective to differentiated myotubes, but also eliminates or attenuates its infectivity to other permissive non-muscle cells. AAV 587 MTP enhanced its tropism for various muscles, especially the heart (24.3 times that of unmodified AAV2), while reducing its tropism for non-muscle tissues (such as liver, lung, and spleen).