Adeno-associated virus-mediated delivery of IL-4 prevents collagen-induced arthritis

Gene therapy for rheumatoid arthritis

Rheumatoid arthritis (RA) is a severe autoimmune systemic disease. Chronic synovial inflammation results in destruction of the joints. No conventional treatment is efficient in RA. Gene therapy of RA targets mainly the players of inflammation or articular destruction: TNF-alpha or IL-1 blocking agents (such as anti-TNF-alpha monoclonal antibodies, soluble TNF-alpha receptor, type II soluble receptor of IL-1, IL-1 receptor antagonist), antiinflammatory cytokines (such as IL-4, IL-10, IL-1), and growth factors. In this polyarticular disease, the vector expressing the therapeutic protein can be administered as a local (intra-articular injection) or a systemic treatment (extra-articular injection). All the main vectors have been used in experimental models, including the more recent lentivirus and adeno-associated virus. Ex vivo gene transfer was performed with synovial cells, fibroblasts, T cells, dendritic cells, and different cells from xenogeneic origin. In vivo gene therapy is simpler, although a less controlled method. Clinical trials in human RA have started with ex vivo retrovirus-expressing IL-1 receptor antagonists and have demonstrated the feasibility of the strategy of gene therapy. The best target remains to be determined and extensive research has to be conducted in preclinical studies.

Light-activated gene transduction enhances adeno-associated virus vector-mediated gene expression in human articular chondrocytes

OBJECTIVE

To evaluate the effects of ultraviolet (UV) light as an adjuvant for recombinant adeno-associated virus (rAAV) transduction in human articular chondrocytes.

METHODS

Primary articular chondrocytes and immortalized chondrocytes (tsT/AC62) were exposed to various doses of UV light (0-1,000 J/m(2)) and infected at various multiplicities of infection (MOIs) with rAAV containing the enhanced green fluorescent protein (EGFP) gene. Cells were analyzed for viability and EGFP expression by fluorescence-activated cell sorting on days 2, 4, and 8 following infection. To evaluate the transduction efficiency in intact articular cartilage, full-thickness explants were exposed to UV light (0-200 J/m(2)), infected with rAAV-eGFP, and analyzed for transduction via immunohistochemistry.

RESULTS

Toxicity from UV exposure was observed at doses > or =500 J/m(2) and > or =200 J/m(2) in primary and immortalized chondrocyte cultures, respectively. Transduction efficiency was dependent on the UV dose, MOI, and time. In the cell line, the adjuvant effect of UV on the percentage of cells transduced was modest, but 100 J/m(2) increased the mean fluorescence intensity (MFI) of the transduced cells 4-fold. In contrast, UV treatment had a profound effect on the transduction efficiency of primary chondrocytes, which reached approximately 100% after exposure to 100 J/m(2) of UV light and 10(3) MOIs for 8 days. Under the same conditions, 200 J/m(2) of UV light enhanced the MFI 7-fold. In cartilage explants, there was no difference in the number of transduced chondrocytes at the edge of the explants in the superficial, intermediate, or basal zones; however, 200 J/m(2) of UV light increased the transduction efficiency 2-fold at a low MOI. In the center of the explants, the superficial chondrocytes were efficiently transduced; those in the intermediate and basal zones could not be efficiently transduced under any condition. In the superficial chondrocytes, a low MOI and 200 J/m(2) of UV light increased the transduction efficiency 3-fold (to 100%).

CONCLUSION

UV light at doses of up to 200 J/m(2) (which do not significantly affect cell viability) significantly enhances the transduction efficiency and expression of the transduced gene in cultures of rAAV-infected primary chondrocytes and in chondrocytes in the superficial zone of intact articular cartilage. These findings support the concept that UV-activated gene transduction could be used as an adjuvant for in vivo rAAV articular cartilage gene therapy with low viral titers to prevent and/or treat arthritis.

Adoptive cellular gene therapy of autoimmune disease

Autoimmune disorders represent inappropriate immune responses directed at self-tissue. Because CD4+ T cells are important mediators in the pathogenesis of autoimmune disease, they are ideal candidates for cell-based gene therapy. Using retrovirally-transduced cells and luciferase bioluminescence, we have demonstrated that primary T cells and hybridomas, rapidly and preferentially home to the sites of inflammation in organ-specific autoimmune disease. These cells, transduced with retroviral vectors to drive expression of various 'regulatory proteins', such as IL-4, IL-10 and IL-12p40, deliver these immunoregulatory proteins to the inflamed lesions, providing therapy for experimental models of autoimmune disease such as EAE, CIA and NOD mice. This technique was originally developed in our lab in the murine model of multiple sclerosis, EAE, where T cell hybridomas reactive with myelin basic protein (MBP) were transduced to express and used to deliver the modulatory cytokine, IL-4. Recently we have observed that the cytokine receptor antagonist, IL-12p40 transduced anti-myelin basic protein (MBP) TCR-transgenic T cells (but not CII-reactive T cells) were effective in preventing EAE whereas the CII-reactive, but not MBP-reactive T cells, transduced to express IL-12p40, would treat CIA.

Tetracycline-inducible interleukin-10 gene transfer mediated by an adeno-associated virus: application to experimental arthritis

The adeno-associated viruses (AAV) offer new perspectives for cytokine gene transfer in rheumatoid arthritis (RA) because they are nonpathogenic and allow long-term transgene expression in vivo. Moreover, the use of a tetracycline-inducible promoter allows regulation of therapeutic gene expression. This study assessed the potential long-term gene regulation of a recombinant AAV vector expressing viral interleukin-10 (vIL-10) in human rheumatoid synovium and the therapeutic efficiency in a mouse model of RA. We constructed a recombinant AAV vector in which the transcription of vIL-10 cDNA is controlled by the TetON system. Transduction of human primary RA synovial cells with AAV-tetON-vIL10 conferred in vitro controlled vIL-10 expression. After intramuscular injection, both incidence and severity of collagen-induced arthritis were significantly reduced at macroscopic, radiological, and histological levels in the group of DBA1 mice treated with AAV-TetON-vIL10 vector plus doxycycline after immunization and boosting compared to control groups. When coinjecting two separate AAV vectors, one encoding the inducible vIL-10 and the other the transcriptional activator, a 10 times excess of the transactivator vector dose allowed efficient control of vIL-10 secretion by doxycycline administration or withdrawal, over an 8-week period. Our results supported, for the first time, the utility of AAV-tetON-vIL10 as a therapeutic tool for gene therapy in RA.

Syngeneic fibroblasts transfected with a plasmid encoding interleukin-4 as non-viral vectors for anti-inflammatory gene therapy in collagen-induced arthritis

BACKGROUND

No effective long-term treatment is available for rheumatoid arthritis. Recent advances in gene therapy and cell therapy have demonstrated efficiency in collagen-induced arthritis (CIA). Interleukin-4 (IL-4) is already known to be efficient in CIA in systemic injection or administered by gene therapy. This study was designed to evaluate the effect of a non-viral gene therapy of CIA, involving injection of syngeneic fibroblasts transfected with a plasmid encoding for IL-4.

METHODS

Immortalised fibroblasts from DBA/1 mice (DBA/1/0 cells) were transfected with a plasmid expressing IL-4 cDNA (DBA/1/IL-4 cells). Xenogeneic fibroblasts from Chinese hamster ovary (CHO) transfected with a plasmid expressing IL-4 cDNA (CHO/IL-4) were studied also. The cells were engrafted in mice developing CIA by subcutaneous injection of 3 x 10(6) DBA/1/0 or DBA/1/IL-4 or CHO/IL-4 cells.

RESULTS

Injection of DBA/1/IL-4 cells, on days 10 and 25 after immunisation, was associated with a significant and lasting improvement in the clinical and histological evidence of joint inflammation and destruction as compared with DBA/1/0 and CHO/IL-4 cells. DBA/1/IL-4 cell treatment decreased also the production of IgG2a antibody to CII and the proliferation of CIIB-specific nodal T cells. Later treatments (engraftments on days 23 and 35 after immunisation) exerted also an anti-inflammatory effect, as evaluated on clinical and histological signs of CIA.

CONCLUSIONS

Taken together, these findings indicate that systemic administration of syngeneic cells transfected with an anti-inflammatory cytokine gene, namely IL-4, with a non-viral method is effective in CIA and may attenuate the cytokine imbalance seen in this disease.

Gene therapy for rheumatoid arthritis. Lessons from animal models, including studies on interleukin-4, interleukin-10, and interleukin-1 receptor antagonist as potential disease modulators

Evidence from animal models convincingly supports the fact that gene therapy can be an advantageous strategy in the treatment of chronic destructive RA. In this article, we review the state of the art in anticytokine gene transfer into the synovial arthritic joint with the emphasis on IL-1Ra, IL-4, and IL-10 effects on CIA in mice. In CIA, only high and continuous release of IL-1Ra protein systemically by mini-osmotic pumps could prevent disease onset and was curative in mice. Local gene transfer seemed to be the obvious way to reach the high local levels that are demanded for protection. It was shown that local IL-1Ra overexpression reduced arthritis incidence and severity as well as tissue destruction. In line with observations about neutralizing antibodies and soluble receptors, gene therapy with TNF soluble receptors provided anti-inflammatory activity in early arthritis but not in advanced arthritis. The limited efficacy at later stages and poor protection against destruction imply that the combination of gene constructs for TNF and IL-1 inhibitors is the obvious direction for future therapy. Apart from targeting of proinflammatory cytokines, adenoviral overexpression of IL-10 and IL-4 may have therapeutic applicability. Local injection of AdIL-10 in the knee joint was effective at the site, but also highly reduced spreading to ipsilateral sites. High local dosages caused suppression in contralateral sites as well. The reports on the anti-inflammatory effect of AdIL-4 are conflicting; however, all present data showed that IL-4 overexpression provides impressive protection against cartilage and bone erosion. Apart from the local effects in the injected joint, it is becoming more and more clear that local treatment also affects arthritis in nearby joints. This is an intriguing general finding, which may enlarge the therapeutic applicability of gene transfer in human arthritis. Proving the feasibility of gene therapy in experimental arthritis, most research efforts are now focused on improving local gene delivery by enhanced viral infection of synovial cells, using RGD-modified adenovirus, or achieving prolonged persistence and regulated expression with AAV. Elegant future alternatives are the application of in vitro engineered T cells as a vehicle capable of specific homing to joint tissues. The feasibility of viral transduction of chondrocytes to obtain a tissue-specific approach to treat articular cartilage damage in arthritis needs further attention.

High-efficiency gene transfer into nontransformed cells: utility for studying gene regulation and analysis of potential therapeutic targets

The elucidation of the signalling pathways involved in inflammatory diseases, such as rheumatoid arthritis, could provide long sought after targets for therapeutic intervention. Gene regulation is complex and varies depending on the cell type, as well as the signal eliciting gene activation. However, cells from certain lineages, such as macrophages, are specialised to degrade exogenous material and consequently do not easily transfect. Methods for high-efficiency gene transfer into primary cells of various lineages and disease states are desirable, as they remove the uncertainties associated with using transformed cell lines. Significant research has been undertaken into the development of nonviral and viral vectors for basic research, and as vehicles for gene therapy. We briefly review the current methods of gene delivery and the difficulties associated with each system. Adenoviruses have been used extensively to examine the role of various cytokines and signal transduction molecules in the pathogenesis of rheumatoid arthritis. This review will focus on the involvement of different signalling molecules in the production of tumour necrosis factor alpha by macrophages and in rheumatoid synovium. While the NF-kappaB pathway has proven to be a major mediator of tumour necrosis factor alpha production, it is not exclusive and work evaluating the involvement of other pathways is ongoing.

Gene therapy in autoimmune disease

Recent work on gene therapies for autoimmune disease has continued to provide insight into the pathogenesis of autoimmunity. Reliable, effective and targeted gene therapy applications have been achieved by using transduced dendritic cells and antigen-specific T cells as delivery vehicles. Bioluminescence imaging has been implemented to visualize cell trafficking and homing in vivo. As a first step into human gene therapy, a phase I clinical trial for assessing the feasibility and safety of gene transfer has been completed in a group of rheumatoid arthritis patients.

Collagen II-pulsed antigen-presenting cells genetically modified to secrete IL-4 down-regulate collagen-induced arthritis

We explored the possibility that pulsed antigen-presenting cells (APC) provide a model vector system for site-specific delivery of immunosuppressive proteins during collagen-induced arthritis (CIA), an animal model for rheumatoid arthritis. Thus, mice were treated with either B cells or macrophages engineered to secrete IL-4 and loaded (or not) with type II collagen (CII). Systemic injection of an IL-4-producing B cell hybridoma resulted in a reduction of arthritis severity which was further improved when APC were incubated with CII before their transfer. Unmanipulated B cells loaded with CII also exerted a potent suppressive effect. Likely, clinical amelioration was observed in mice given at priming syngeneic bone marrow-derived macrophages producing IL-4 and pulsed with CII in comparison to the other groups. When the same dose of cells was transferred at disease onset, a moderate beneficial effect was observed. Whatever the APC inoculated, the beneficial effect did not rely upon an IL-4-driven shift towards Th2 phenotype. Systemic administration of fluorescent dye labeled macrophages to arthritic mice has shown that some of these cells rapidly migrate to joints. Moreover, IL-4 transfected macrophages retained their potent capacity to present CII peptides to T cells. These findings validate the use of CII peptide-loaded engineered APC as therapeutic vector cells in CIA and allow consideration of this strategy for the administration of various anti-inflammatory proteins.

Anticytokine gene therapy of autoimmune diseases

Viral and nonviral gene therapy vectors have been successfully employed to deliver inflammatory cytokine inhibitors (anticytokines), or anti-inflammatory cytokines, such as transforming growth factor beta-1 (TGF-beta 1), which protect against experimental autoimmune diseases. These vectors carry the relevant genes into a variety of tissues, for either localised or systemic release of the encoded protein. Administration of cDNA encoding soluble IFN-gamma receptor (IFN-gamma R)/IgG-Fc fusion proteins, soluble TNF-alpha receptors, or IL-1 receptor antagonist (IL-1ra), protects against either lupus, various forms of arthritis, autoimmune diabetes, or other autoimmune diseases. These inhibitors, unlike many cytokines, have little or no toxic potential. Similarly, TGF-beta 1 gene therapy protects against numerous forms of autoimmunity, though its administration entails more risk than anticytokine therapy. We have relied on the injection of naked plasmid DNA into skeletal muscle, with or without enhancement of gene transfer by in vivo electroporation. Expression plasmids offer interesting advantages over viral vectors, since they are simple to produce, non-immunogenic and nonpathogenic. They can be repeatedly administered and after each treatment the encoded proteins are produced for relatively long periods, ranging from weeks to months. Moreover, soluble receptors which block cytokine action, encoded by gene therapy vectors, can be constructed from non-immunogenic self elements that are unlikely to be neutralised by the host immune response (unlike monoclonal antibodies [mAbs]), allowing long-term gene therapy of chronic inflammatory disorders.