Adeno-associated virus mediates long-term gene transfer and delivery of chondroprotective IL-4 to murine synovium.

Treatments for rheumatoid arthritis and other inflammatory arthropathies are often ineffective at preventing joint destruction. Long-term genetic modification of the cells lining the joint space (synoviocytes) in vivo represents a potential method for the treatment of these chronic conditions. However, a vector capable of efficiently transducing synoviocytes in vivo for a persistent period has not been available. The present report describes the genetic modification of synoviocytes in vivo using recombinant adeno-associated virus. High-titer adeno-associated virus encoding the gene for Escherichia coli beta-galactosidase was injected into the knee joints of mice. Synovial tissues were then examined for beta-galactosidase transgene expression by in situ staining and by fluorometry. High-efficiency, persistent transgene expression was observed in the synovium with no evidence of vector-induced inflammation. Expression was observed for at least 7 months and was higher in arthritic than nonarthritic mice. Gene transfer of murine IL-4 to the joints of mice with collagen-induced arthritis led to detectable levels of IL-4 in the joint and protection from articular cartilage destruction. These data suggest that adeno-associated virus may be a useful vector for gene delivery to the synovium for the treatment of inflammatory arthropathies.