Activation of the NF-[kappa]B pathway by adeno-associated virus (AAV) vectors and its implications in immune response and gene therapy

• Published in: Proceedings of the National Academy of Sciences - PNAS 2011-03, Vol.108 (9), p.3743
• Main Authors: Jayandharan, Giridhara R, Aslanidi, George, Martino, Ashley T, Jahn, Stephan C, Perrin, George Q, Herzog, Roland W, Srivastava, Arun
• Format: Article
• Language: English
• Subjects: Binding sites; Cytokines; Gene expression; Gene therapy; Molecules; Proteins; Signal transduction; Viruses
• ISSN: 0027-8424; 1091-6490

Because our in silico analysis with a human transcription factor database demonstrated the presence of several binding sites for NF-...B, a central regulator of cellular immune and inflammatory responses, in the adeno-associated virus (AAV) genome, we investigated whether AAV uses NF-...B during its life cycle. We used small molecule modulators of NF-...B in HeLa cells transduced with recombinant AAV vectors. VP16, an NF-...B activator, augmented AAV vector-mediated transgene expression up to 25-fold. Of the two NF-...B inhibitors, Bay11, which blocks both the canonical and the alternative NF-...B pathways, totally ablated transgene expression, whereas pyrrolidone dithiocarbamate, which interferes with the classical NF-...B pathway, had no effect. Western blot analyses confirmed the abundance of the nuclear p52 protein component of the alternative NF-...B pathway in the presence of VP16, which was ablated by Bay11, suggesting that AAV transduction activates the alternative NF-...B pathway. In vivo, hepatic AAV gene transfer activated the canonical NF-...B pathway within 2 h, resulting in expression of proinflammatory cytokines and chemokines (likely reflecting the sensing of viral particles by antigen-presenting cells), whereas the alternative pathway was activated by 9 h. Bay11 effectively blocked activation of both pathways without interfering with long-term transgene expression while eliminating proinflammatory cytokine expression. These studies suggest that transient immunosuppression with NF-...B inhibitors before transduction with AAV vectors should lead to a dampened immune response, which has significant implications in the optimal use of AAV vectors in human gene therapy. (ProQuest: ... denotes formulae/symbols omitted.)