Intra-articular gene delivery and expression of interleukin-1Ra mediated by self-complementary adeno-associated virus.

BACKGROUND: The adeno-associated virus (AAV) has many safety features that favor its use in the treatment of arthritic conditions; however, the conventional, single-stranded vector is inefficient for gene delivery to fibroblastic cells that primarily populate articular tissues. This has been attributed to the inability of these cells to convert the vector to a double-stranded form. To overcome this, we evaluated double-stranded self-complementary (sc) AAV as a vehicle for intra-articular gene delivery. METHODS: Conventional and scAAV vectors were used to infect lapine articular fibroblasts in culture to determine transduction efficiency, transgene expression levels, and nuclear trafficking. scAAV containing the cDNA for interleukin (IL)-1 receptor antagonist (Ra) was delivered to the joints of naïve rabbits and those with IL-1beta-induced arthritis. From lavage of the joint space, levels of transgenic expression and persistence were measured by enzyme-linked immunosorbent assay. Infiltrating leukocytes were quantified using a hemocytometer. RESULTS: Transgene expression from scAAV had an earlier onset and was approximately 25-fold greater than conventional AAV despite the presence of similar numbers of viral genomes in the nuclei of infected cells. Fibroblasts transduced with scAAV produced amounts of IL1-Ra comparable to those transduced with adenoviral and lentiviral vectors. IL1-Ra was present in lavage fluid of most animals for 2 weeks in sufficient quantities to inhibit inflammation of the IL-1beta-driven model. Once lost, neither subsequent inflammatory events, nor re-administration of the virus could re-establish transgene expression. CONCLUSIONS: scAAV-mediated intra-articular gene transfer is robust and similarly efficient in both normal and inflamed joints; the resulting transgenic expression is sufficient to achieve biological relevance in joints of human proportion.

Targeting B cells for the treatment of rheumatoid arthritis.

The role of B cells in rheumatoid arthritis (RA) has been debated for decades. However, recent clinical trial data indicating that depletion of B cells in RA patients is of therapeutic benefit has validated the importance of this cell type in the pathogenesis of the disease. Elucidation of the molecular basis of B cell development and activation has allowed the identification of a number of possible therapeutic targets that are appealing for drug development. This review discusses briefly a number of these molecules and the rationale for targeting them for the treatment of RA.

Effective treatment of established mouse collagen-induced arthritis by systemic administration of dendritic cells genetically modified to express FasL.

Previous reports have demonstrated the ability of antigen-presenting cells (APCs), genetically modified to express Fas ligand (FasL), to inhibit T-cell responses through the induction of apoptosis of antigen-specific T cells. Here we have examined the ability of primary mouse bone marrow-derived dendritic cells (DCs), genetically modified by adenoviral infection to express FasL, to inhibit progression of established collagen-induced arthritis (CIA) in DBA/1 mice. Systemic injection of DC/FasL into mice with established CIA resulted in substantial disease amelioration as determined by analysis of paw swelling, arthritic index, and number of arthritic paws. Moreover, a single injection of DC/FasL resulted in extended suppression of disease. We also demonstrate that treatment of arthritic mice with DC/FasL suppressed interferon-gamma (IFN-gamma) production from spleen-derived lymphocytes and reduced T-cell proliferation following collagen stimulation without affecting the levels of anti-collagen antibody isotypes. These results demonstrate that systemic administration of DC/FasL is able to suppress collagen-reactive T cells, resulting in effective and sustained treatment of established CIA.

Ex vivo gene delivery of IL-1Ra and soluble TNF receptor confers a distal synergistic therapeutic effect in antigen-induced arthritis.

Intra-articular expression of antagonists of interleukin-1beta (IL-1beta) and tumor necrosis factor-alpha (TNF-alpha) in arthritic rabbit knee and mouse ankle joints by direct adenoviral-mediated intraarticular delivery results in amelioration of disease pathology in both the treated and contralateral untreated joints. Previous experiments suggest that direct adenoviral infection of resident antigen-presenting cells (APCs) and subsequent traveling of these cells to other sites of inflammation and lymph nodes might be responsible for this "contralateral effect." To determine whether genetic modification of APCs is required for the contralateral effect, we have used an ex vivo approach utilizing genetically modified fibroblasts to express IL-1 receptor antagonist protein (IL-1Ra) and soluble TNF-alpha receptor (sTNFR) locally in arthritic joints. Retroviral vectors carrying IL-1Ra, sTNFR-Ig, or both genes together were used to stably infect autologous rabbit fibroblasts that were then injected intra-articularly into arthritic rabbit knee joints. The intra-articular delivery of either IL-1Ra- or sTNFR-Ig-expressing fibroblasts was antiinflammatory and chondro-protective in both the injected and noninjected contralateral joints. In addition, we demonstrate that the co-delivery of both antagonists in combination results in a synergistic effect in disease amelioration in both the treated and nontreated joints. These ex vivo results suggest that trafficking of vector-modified inflammatory cells is not the main mechanism responsible for the observed distal spread of the therapeutic effect. Moreover, the results demonstrate that local, ex vivo gene therapy for arthritis could be effective in blocking pathologies within untreated, distant arthritic joints.