Laurie R. Goodrich¹ , Vivian W. Choi ² , Beth C. DudaCarbone¹ , C. Wayne McIlwraith¹, R. Jude Samulski ².
¹Colorado State University, Fort Collins, CO, United States, ²University of North Carolina, Chapel Hill, Chapel Hill, NC, United States

ACVS Abstract 2007

Recombinant adeno-associated virus (rAAV) is an emerging vector for joint diseases due to its potential to efficiently express therapeutic genes and its purported low incidence of cell toxicity. We investigated the best AAV serotype to deliver a self-complementary AAV (scAAV) genome to chondrocytes and synoviocytes. Chondrocytes and synoviocytes were grown in monolayer. Two days after seeding, scAAV vector serotypes 1–6, and 8, carrying a GFP expression cassette were used to transduce cells. Fluorescence intensity was measured. Following initial testing, 4 optimal serotypes were tested at various doses and fluorescence intensity was measured.

Cell viability was determined and vector toxicity was tested by relative gene expression of equine MMP-1, MMP-3, MMP-13 and Aggrecanase-1. Chondrocytes and synoviocytes revealed optimal transduction with serotyes 2, 3, 5 and 6. Doses of 8000 and 4000 viral particles per cell were similar. Serotypes 2, 3, 5 and 6 revealed transduction efficiencies of 50–90% in both chondrocytes and synoviocytes at day three and continued to express high levels of GFP at 14 days. GFP-positive cells were still evident 6 weeks posttransduction. Cell viability of both chondrocytes and synoviocytes was determined to be over 80%. Quantitative PCR revealed minimal toxicity for the optimal serotypes tested.

We established the use of specific scAAV serotypes for efficient tissue targeting with persistent transgene expression on chondrocytes and synoviocytes, which enhances the likelihood of successful gene therapy for joint diseases such as osteoarthritis. Further investigation on animal models and clinical applications of our system will be developed for therapeutic uses.