Reduction of arthritis following intra-articular administration of an adeno-associated virus serotype 5 expressing a disease-inducible TNF-blocking agent

Immunoengineering the next generation of arthritis therapies

Immunoengineering continues to revolutionize healthcare, generating new approaches for treating previously intractable diseases, particularly in regard to cancer immunotherapy. In joint diseases, such as osteoarthritis (OA) and rheumatoid arthritis (RA), biomaterials and anti-cytokine treatments have previously been at that forefront of therapeutic innovation. However, while many of the existing anti-cytokine treatments are successful for a subset of patients, these treatments can also pose severe risks, adverse events and off-target effects due to continuous delivery at high dosages or a lack of disease-specific targets. The inadequacy of these current treatments has motivated the development of new immunoengineering strategies that offer safer and more efficacious alternative therapies through the precise and controlled targeting of specific upstream immune responses, including direct and mechanistically-driven immunoengineering approaches. Advances in the understanding of the immunomodulatory pathways involved in musculoskeletal disease, in combination with the growing emphasis on personalized medicine, stress the need for carefully considering the delivery strategies and therapeutic targets when designing therapeutics to better treat RA and OA. Here, we focus on recent advances in biomaterial and cell-based immunomodulation, in combination with genetic engineering, for therapeutic applications in joint diseases. The application of immunoengineering principles to the study of joint disease will not only help to elucidate the mechanisms of disease pathogenesis but will also generate novel disease-specific therapeutics by harnessing cellular and biomaterial responses. STATEMENT OF SIGNIFICANCE: It is now apparent that joint diseases such as osteoarthritis and rheumatoid arthritis involve the immune system at both local (i.e., within the joint) and systemic levels. In this regard, targeting the immune system using both biomaterial-based or cellular approaches may generate new joint-specific treatment strategies that are well-controlled, safe, and efficacious. In this review, we focus on recent advances in immunoengineering that leverage biomaterials and/or genetically engineered cells for therapeutic applications in joint diseases. The application of such approaches, especially synergistic strategies that target multiple immunoregulatory pathways, has the potential to revolutionize our understanding, treatment, and prevention of joint diseases.

A Synthetic Gene Circuit for Self-Regulating Delivery of Biologic Drugs in Engineered Tissues

IMPACT STATEMENT

We engineered a synthetic transcription system based on nuclear factor kappa-light-chain-enhancer of activated B cells signaling that can attenuate the effects of the inflammatory cytokine interleukin (IL)-1α in a self-regulating manner. This system responds in a time- and dose-dependent manner to rapidly produce therapeutic levels of IL-1 receptor antagonist (IL-1Ra). The use of lentiviral gene therapy allows this system to be utilized through different transduction methods and in different cell types for a variety of applications. Broadly, this approach may be applicable in developing autoregulated biologic systems for tissue engineering and drug delivery in a range of disease applications.

Recent tissue engineering-based advances for effective rAAV-mediated gene transfer in the musculoskeletal system

Musculoskeletal tissues are diverse and significantly different in their ability to repair upon injury. Current treatments often fail to reproduce the natural functions of the native tissue, leading to an imperfect healing. Gene therapy might improve the repair of tissues by providing a temporarily and spatially defined expression of the therapeutic gene(s) at the site of the injury. Several gene transfer vehicles have been developed to modify various human cells and tissues from musculoskeletal system among which the non-pathogenic, effective, and relatively safe recombinant adeno-associated viral (rAAV) vectors that have emerged as the preferred gene delivery system to treat human disorders. Adapting tissue engineering platforms to gene transfer approaches mediated by rAAV vectors is an attractive tool to circumvent both the limitations of the current therapeutic options to promote an effective healing of the tissue and the natural obstacles from these clinically adapted vectors to achieve an efficient and durable gene expression of the therapeutic sequences within the lesions.

Assembly PCR synthesis of optimally designed, compact, multi-responsive promoters suited to gene therapy application

Gene therapy has the potential to provide innovative treatments for genetic and non-genetic diseases, with the ability to auto-regulate expression levels of therapeutic molecules so that they are produced locally and in direct response to disease activity. Generating disease responsive gene therapy vectors requires knowledge of the activation profile of transcription factors (TFs) during active disease, in order to assemble binding sites for these TFs into synthetic promoters, which can be appropriately activated by the disease process. In this study, we optimised a PCR random assembly approach to generate promoters with optimal spacing between TF binding sites (TFBSs) and their distance from the TATA box. In promoters with optimal spacing, it was possible to demonstrate activation by individual transcription pathways and either additive or synergistic promoter activation when transfected cells were treated with combined stimuli. The kinetics and sensitivity of promoter activation was further explored in transduced cells and when lentivirus was directly delivered to mouse paws a synthetic promoter demonstrated excellent activation by real-time imaging in response to local inflammation.

MicroRNA-15b Modulates Molecular Mediators of Blood Induced Arthropathy in Hemophilia Mice

The development of arthropathy is a major co-morbidity in patients with hemophilia. The present study was designed to study the role of a microRNA biomarker (miR-15b) in the development of joint disease. To investigate the expression profile of miR-15b during the development of arthropathy, we first isolated and studied small RNA from the acute and chronic hemarthrosis model of hemophilia A mice. We observed that miR-15b was consistently repressed (~1- to 4-fold) from the onset of joint bleeding (1, 3, 7 and 24 h) until six bleeding episodes (up to 90 days). To test if reconstitution of miR-15b modulates biomarkers of joint damage in a chronic hemarthrosis model, we administered an adeno-associated virus (AAV) 5-miR-15b vector intra-articularly alone or in combination with systemic administration of AAV2-factor VIII. miR-15b overexpression downregulated markers of angiogenesis and hypoxia (vascular epithelial growth factor α (VEGF-α) and hypoxia inducing factor 2α (HIF-2α), ~70% and ~34%, respectively) in the affected joints. In addition, the co-administration of miR-15b and factor VIII vectors reduced the levels of the chondrodegenerative matrix-metalloproteinases (MMPs) 1, 3, 9 and 14 (~14% to 60%) in the injured joints. These data demonstrate for the first time the role of a miR-15b in the development of hemophilic arthropathy and has implications in development of miR based therapies for joint disease.

In vitro evaluation of effects of sustained anti-TNF release from MPEG-PCL-MPEG and PCL microspheres on human rheumatoid arthritis synoviocytes

Anti-tumor necrosis factor α (TNFα) drugs such as etanercept (ETN) have been mostly used in systemic treatment of rheumatoid arthritis. To eliminate the side effects in long-term treatments and to achieve a local sustained anti-inflammatory effect, a controlled drug delivery system is needed for anti-TNFα drugs. This study aims to develop novel injectable microcarriers of ETN that can provide long-term controlled release of this protein drug upon intra-articular application. In this study, poly(ε-caprolactone) (PCL) and its copolymer with poly(ethylene glycol), methoxypoly(ethylene glycol)-poly(ε-caprolactone)-methoxypoly(ethylene glycol) microspheres (MPEG-PCL-MPEG) were compared for their prospective success in rheumatoid arthritis treatment. Microspheres with smooth surface of a mean particle diameter of approximately 5 μm were prepared with both polymers. MPEG-PCL-MPEG microspheres had higher encapsulation efficiency than PCL microspheres. The activity of encapsulated ETN within MPEG-PCL-MPEG microspheres also retained while 90% of the activity of ETN within PCL microspheres could retain during 90-day release. MPEG-PCL-MPEG microspheres showed faster ETN release compared to PCL microspheres in various release media. Cumulative amounts of ETN released from both types of microspheres were significantly lower in cell culture medium and in synovial fluids than in phosphate buffered saline. This was mainly due to protein adsorption onto microspheres. Hydrophilic MPEG segment enhanced ETN release while preventing protein adsorption on microspheres compared to PCL. Sustained ETN release from microspheres resulted with a significant decrease in pro-inflammatory cytokines (TNFα, IFNγ, IL-6, IL-17) and MMP levels (MMP-3, MMP-13), while conserving viability of fibroblast-like synoviocytes compared to the free drug. Results suggest that MPEG-PCL-MPEG is a potential copolymer of PCL that can be used in development of biomedical materials for effective local treatment purposes in chronic inflammatory arthritis owing to enhanced hydrophilicity. Yet, PCL microspheres are also promising systems having good compatibility to synoviocytes and would be especially the choice for treatment approach requiring longer term and slower release.

Therapeutic improvement of a stroma-targeted CRAd by incorporating motives responsive to the melanoma microenvironment

We have previously designed a conditionally replicative oncolytic adenovirus (CRAd) named Ad-F512 that can target both the stromal and the malignant melanoma cell compartments. The replication capacity of this CRAd is driven by a 0.5-Kb SPARC promoter fragment (named F512). To improve CRAd's efficacy, we cloned into F512 motives responsive to hypoxia (hypoxia-responsive element (HRE)) and inflammation (nuclear factor kappa B) to obtain a chimeric promoter named κBF512HRE. Using luciferase as a reporter gene, we observed 10-15-fold increased activity under hypoxia and 10-80-fold induction upon tumor necrosis factor-α addition. We next constructed a CRAd (Ad-κBF512HRE) where E1A activity was under κBF512HRE regulation. Treatment of nude mice harboring established tumors made of a mix of SB2 melanoma cells and WI-38 fibroblasts with Ad-κBF512HRE led to the complete elimination of tumors in 100% of mice (8/8). Moreover, Ad-5/3-κBF512HRE, a viral variant pseudotyped with a chimeric 5/3 fiber, exerted a strong lytic effect on CAR-negative melanoma cells and was highly effective in vivo on established tumors made of melanoma cells and WI-38 fibroblasts, leading to the complete elimination of 4/5 tumors. These results indicate that this improved stroma-targeted oncolytic adenovirus can override the resistance of melanoma tumors and might become of significant importance for melanoma therapeutics.

An adeno-associated virus-based intracellular sensor of pathological nuclear factor-κB activation for disease-inducible gene transfer

Stimulation of resident cells by NF-κB activating cytokines is a central element of inflammatory and degenerative disorders of the central nervous system (CNS). This disease-mediated NF-κB activation could be used to drive transgene expression selectively in affected cells, using adeno-associated virus (AAV)-mediated gene transfer. We have constructed a series of AAV vectors expressing GFP under the control of different promoters including NF-κB -responsive elements. As an initial screen, the vectors were tested in vitro in HEK-293T cells treated with TNF-α. The best profile of GFP induction was obtained with a promoter containing two blocks of four NF-κB -responsive sequences from the human JCV neurotropic polyoma virus promoter, fused to a new tight minimal CMV promoter, optimally distant from each other. A therapeutical gene, glial cell line-derived neurotrophic factor (GDNF) cDNA under the control of serotype 1-encapsidated NF-κB -responsive AAV vector (AAV-NF) was protective in senescent cultures of mouse cortical neurons. AAV-NF was then evaluated in vivo in the kainic acid (KA)-induced status epilepticus rat model for temporal lobe epilepsy, a major neurological disorder with a central pathophysiological role for NF-κB activation. We demonstrate that AAV-NF, injected in the hippocampus, responded to disease induction by mediating GFP expression, preferentially in CA1 and CA3 neurons and astrocytes, specifically in regions where inflammatory markers were also induced. Altogether, these data demonstrate the feasibility to use disease-activated transcription factor-responsive elements in order to drive transgene expression specifically in affected cells in inflammatory CNS disorders using AAV-mediated gene transfer.

Epirubicin potentiates recombinant adeno-associated virus type 2/5-mediated TRAIL expression in fibroblast-like synoviocytes and augments the antiarthritic effects of rAAV2/5-TRAIL

OBJECTIVE

Synovial cells in rheumatoid synovium display abnormal proliferation, which leads to joint destruction. TRAIL has been described as a proapoptotic factor in fibroblast-like synoviocytes (FLS). This study was undertaken to investigate the functions of rAAV2/5-TRAIL in human FLS and in arthritic mice.

METHODS

Primary human FLS were infected with rAAV2/5-TRAIL in the presence or absence of epirubicin. Transgene expression was monitored by both enzyme-linked immunosorbent assay and flow cytometry. The disease-modulating activity of epirubicin plus rAAV2/5-TRAIL was investigated in mice with collagen-induced arthritis (CIA).

RESULTS

Subtoxic doses of epirubicin potentiated rAAV2/5-mediated TRAIL expression in FLS and simultaneously enhanced the sensitivity of FLS to TRAIL. Epirubicin treatment up-regulated death receptor 4 (DR-4) and DR-5 expression and down-regulated FLIP expression, thereby enhancing the activation of procaspase 3, procaspase 8, and procaspase 9. An in vivo study showed that the combination of rAAV2/5-TRAIL gene therapy and epirubicin chemotherapy provided augmented antiarthritic effects in a mouse model of CIA. The intraarticular injection of rAAV2/5-TRAIL combined with epirubicin treatment significantly reduced the severity and incidence of CIA and joint swelling in the animals. Histologic evaluations revealed that inflammatory cell infiltration, cartilage destruction, and bone erosion were significantly reduced in the joints of the mice receiving the synthetic treatment. Results of a viral genome copy number assay indicated that epirubicin dramatically augmented the expression of rAAV2/5-TRAIL without altering its tissue distribution.

CONCLUSION

These results suggest that epirubicin enhances the antiarthritic effect of rAAV2/5-TRAIL and that combination treatment might be an important therapeutic alternative, with practical significance for rheumatoid arthritis.

Exploiting natural diversity of AAV for the design of vectors with novel properties

Twelve AAV serotypes have been described so far in human and nonhuman primate (NHP) populations while surprisingly high diversity of AAV sequences is detected in tissue biopsies. The analysis of these novel AAV sequences has indicated a rapid evolution of the viral genome both by accumulation of mutations and recombination. This chapter describes how this rich resource of naturally evolved sequences is used to derive gene transfer vectors with a wide array of activities depending on the nature of the cap gene used in the packaging system. AAV2-based recombinant genomes have been packaged in dozens of different capsid types, resulting in a wide array of "pseudotyped vectors" that constitute a rich resource for the development of gene therapy clinical trials. We describe a polymerase chain reaction-based molecular rescue method for novel AAV isolation that uses primers designed to recognize the highly conserved regions in known AAV isolates and generate amplicons across the hypervariable regions of novel AAV genomes present in the analyzed sample.

A novel hybrid promoter responsive to pathophysiological and pharmacological regulation

The aim of this study was to construct a promoter containing DNA motifs for an endogenous transcription factor associated with inflammation along with motifs for pharmacological regulation factors. We demonstrate in transfected cells that expression of a gene of interest is induced by hypoxic conditions or through pharmacological induction, and also show pharmacological repression. In vivo studies utilised electroporation of plasmid to mouse paws, a delivery method shown to be effective by bioluminescence imaging. For gene therapy, the promoter was used to drive expression of IL-1Ra in a paw inflammation model with therapeutic effect observed which was further enhanced when the promoter was additionally induced with a pharmacological activator. One of the most important observations from this study was that promoter induction by hypoxia or inflammation could be prevented by the pharmacological repressor in the absence of doxycycline. These studies demonstrate that hybrid promoters enable pharmacological adjustment to the pathophysiological level of gene expression and, importantly, that they allow termination of gene expression even in the presence of pathophysiological stimuli.

Advancements in adeno-associated viral gene therapy approaches: exploring a new horizon

Gene therapy is a promising new therapeutic strategy that has been explored in a wide variety of diseases, ranging from cancer to hemophilia, and ocular disorders to autoimmune diseases, among others. Proof of concept of gene transfer approaches has been shown in over 100 studies of animal models of disease, although only a few are under development for clinical application. The US Food and Drug Administration and the European Medicines Agency have not approved any viral human gene therapy products for sale so far, but the amount of gene-related research and development occurring in the United States and Europe continues to grow at a fast rate. This review summarizes the current status of developments in the field of viral gene therapy using adeno-associated virus as a vector, with a special focus on arthritis. For rheumatoid arthritis, and to a lesser extent for other immune-related inflammatory disorders, several cell and gene transfer approaches have been investigated at the preclinical level and a few have been implemented in clinical trials. Finally, both the potential and the hurdles that are faced during development of a viral gene therapy through to its clinical application are discussed.

Modulation of immune and inflammatory responses on experimental arthritis following intraarticular gene transfer of tumor necrosis factor receptor-immunoglobulin Fc

In spite of popularity of TNF-α antagonist in the treatment of rheumatoid arthritis (RA), their modes of action are not fully understood. In the present study, we further explore the effects of gene transfer route of a TNF-α antagonist on arthritis. Recombinant adeno-associated virus 2 (rAAV2) encoding rat TNF receptor-immunoglobulin Fc (ratTNFR:Fc) fusion gene was injected intraarticularly in rats with collagen-induced arthritis (CIA). As revealed by examination of the clinical, radiographical, and histological aspects, local gene transfer of rAAV2/ratTNFR:Fc ameliorated the arthritis symptoms and inhibited the development of CIA. Compared with the vector control group, expressions of TNF-α, IL-1, and IFN-γ were down-regulated, and IL-10 release was up-regulated in the rAAV2/ratTNFR:Fc-treated group. Furthermore, administration of rAAV2/ratTNFR:Fc ameliorated the enlargement of spleen and significantly reduced spleen cell proliferation. Low level of nitric oxide (NO) in spleen was observed in CIA rats following the delivery of rAAV2/ratTNFR:Fc when compared to the vector control group. This study provides the evidence that intraarticular delivery of rAAV2/ratTNFR:Fc suppress the progression of arthritis by restoring the balance between pro-inflammatory and anti-inflammatory cytokines and inhibiting spleen cell proliferation. Our findings also implicate that the down-regulation of NO release on arthritis is involved in the anti-inflammatory mechanisms of TNF-α antagonist.

Single intra-articular injection of adeno-associated virus results in stable and controllable in vivo transgene expression in normal rat knees

OBJECTIVE

To test the hypothesis that in vivo transgene expression mediated by single intra-articular injection of adeno-associated virus serotype 2 (AAV2) persists within intra-articular tissues 1 year post-injection and can be externally controlled using an AAV2-based tetracycline-inducible gene regulation system containing the tetracycline response element (TRE) promoter.

METHODS

Sprague Dawley rats received intra-articular injections of AAV2-cytomegalovirus (CMV)-enhanced green fluorescent protein (GFP) and AAV2-CMV-luciferase (Luc) into their right and left knees, respectively. Luciferase expression was evaluated over 1 year using bioluminescence imaging. After sacrifice, tissues were analyzed for GFP+ cells by fluorescent microscopy. To study external control of intra-articular AAV-transgene expression, another set of rats was co-injected with AAV2-TRE-Luc and AAV2-CMV-reverse-tetracycline-controlled transactivator (rtTA) into the right knees, and AAV2-CMV-Luc and AAV2-CMV-rtTA into the left knees. Rats received oral doxycycline (Dox), an analog of tetracycline, for 7 days. Luciferase expression was assessed by bioluminescence imaging.

RESULTS

Luciferase expression was localized to the injected joint and persisted throughout the 1-year study period. Abundant GFP+ cells were observed within intra-articular soft tissues. Transgene expression in AAV2-TRE-Luc injected joints was upregulated by oral administration of Dox, and downregulated following its removal, at 14 days and 13 months post-AAV injection.

CONCLUSIONS

This longitudinal in vivo study shows that sustained and stable AAV-mediated intra-articular transgene expression can be achieved through a single intra-articular injection and can be controlled using a tetracycline-controlled inducible AAV system in a normal rat knee model. Highly regulatable long-term intra-articular transgene expression is of potential clinical utility for development of treatment strategies for chronic intra-articular disease processes such as inflammatory and degenerative arthritis.

Intra-articular electrotransfer of mouse soluble tumour necrosis factor receptor in a murine model of rheumatoid arthritis

BACKGROUND

Rheumatoid arthritis (RA) is a chronic autoimmune disease that causes inflammation and destruction of the joints. In the collagen-induced arthritis mouse model of RA, we developed a nonviral gene therapy method designed to block in situ the main cytokine tumour necrosis factor (TNF)-alpha

METHODS

Electrotransfer was used to deliver a plasmid encoding extracellular domain of mouse soluble TNF-alpha receptor type I fused to the Fc fragment of mouse immunoglobulin (Ig)G1 (pTNFR-Is) corresponding to a dimeric TNF-alpha soluble receptor fusion protein (mTNFR-Is/Ig).

RESULTS

Delivery of the plasmid into the knees at symptom onset improved the histological inflammation and destruction not only at the knees, but also at the ankles, indicating a local and a regional therapeutic effect. The plasmid was detected in synovial membrane and meniscus specimens from the injected joints. In the synovial membrane, 15 days post-injection, interleukin (IL)-17 and TNF-alpha mRNAs expression were increased, whereas IL-10 mRNA was unchanged. However, the empty plasmid exerted a pro-inflammatory effect 30 days post-injection.

CONCLUSIONS

These data indicate that local nonviral gene therapy against TNF-alpha is effective, although further work is needed to decrease plasmid induced inflammation.

Evaluating intra-articular drug delivery for the treatment of osteoarthritis in a rat model

Osteoarthritis (OA) is a degenerative joint disease that can result in joint pain, loss of joint function, and deleterious effects on activity levels and lifestyle habits. Current therapies for OA are largely aimed at symptomatic relief and may have limited effects on the underlying cascade of joint degradation. Local drug delivery strategies may provide for the development of more successful OA treatment outcomes that have potential to reduce local joint inflammation, reduce joint destruction, offer pain relief, and restore patient activity levels and joint function. As increasing interest turns toward intra-articular drug delivery routes, parallel interest has emerged in evaluating drug biodistribution, safety, and efficacy in preclinical models. Rodent models provide major advantages for the development of drug delivery strategies, chiefly because of lower cost, successful replication of human OA-like characteristics, rapid disease development, and small joint volumes that enable use of lower total drug amounts during protocol development. These models, however, also offer the potential to investigate the therapeutic effects of local drug therapy on animal behavior, including pain sensitivity thresholds and locomotion characteristics. Herein, we describe a translational paradigm for the evaluation of an intra-articular drug delivery strategy in a rat OA model. This model, a rat interleukin-1beta overexpression model, offers the ability to evaluate anti-interleukin-1 therapeutics for drug biodistribution, activity, and safety as well as the therapeutic relief of disease symptoms. Once the action against interleukin-1 is confirmed in vivo, the newly developed anti-inflammatory drug can be evaluated for evidence of disease-modifying effects in more complex preclinical models.

Local expression of tumor necrosis factor-receptor 1:immunoglobulin G can induce salivary gland dysfunction in a murine model of Sjögren's syndrome

Introduction

Tumor necrosis factor is a pleiotropic cytokine with potent immune regulatory functions. Although tumor necrosis factor inhibitors have demonstrated great utility in treating other autoimmune diseases, such as rheumatoid arthritis, there are conflicting results in Sjögren's syndrome. The aim of this study was to assess the effect of a locally expressed tumor necrosis factor inhibitor on the salivary gland function and histopathology in an animal model of Sjögren's syndrome.

Methods

Using in vivo adeno associated viral gene transfer, we have stably expressed soluble tumor necrosis factor-receptor 1-Fc fusion protein locally in the salivary glands in the Non Obese Diabetic model of Sjögren's syndrome. Pilocarpine stimulated saliva flow was measured to address the salivary gland function and salivary glands were analyzed for focus score and cytokine profiles. Additionally, cytokines and autoantibody levels were measured in plasma.

Results

Local expression of tumor necrosis factor-receptor 1:immunoglobulin G fusion protein resulted in decreased saliva flow over time. While no change in lymphocytic infiltrates or autoantibody levels was detected, statistically significant increased levels of tumor growth factor-β1 and decreased levels of interleukin-5, interleukin-12p70 and interleukin -17 were detected in the salivary glands. In contrast, plasma levels showed significantly decreased levels of tumor growth factor-β1 and increased levels of interleukin-4, interferon-γ, interleukin-10 and interleukin-12p70.

Conclusions

Our findings suggest that expression of tumor necrosis factor inhibitors in the salivary gland can have a negative effect on salivary gland function and that other cytokines should be explored as points for therapeutic intervention in Sjögren's syndrome.

[Molecular tools to remodel osteoarthritic articular cartilage : growth, transcription, and signaling factors]

Osteoarthritis (OA) is a chronic disorder of the diarthrodial joints, mostly characterized by gradual deterioration of the articular cartilage. This disease still has no effective treatment. An emerging strategy for treating OA is based on molecular concepts using growth factors, transcription factors, and signaling molecules in light of their effects on the restoration of cartilage integrity. Recent studies have demonstrated that overexpression of such candidate molecules using direct gene transfer or ex vivo protocols is capable of stimulating cell proliferation and matrix synthesis in normal human and OA cartilage explants in vitro as well as in animal models in vivo. As a result, the structure of the articular cartilage can be improved. More insights into the pathophysiology of human OA and further studies in animal models are needed, however, to facilitate clinical translation of these molecular approaches. In conclusion, recent experimental findings permit cautious optimism, holding promise for treating human OA in the future.

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.

Computational design and application of endogenous promoters for transcriptionally targeted gene therapy for rheumatoid arthritis

The promoter regions of genes that are differentially regulated in the synovial membrane during the course of rheumatoid arthritis (RA) represent attractive candidates for application in transcriptionally targeted gene therapy. In this study, we applied an unbiased computational approach to define proximal-promoters from a gene expression profiling study of murine experimental arthritis. Synovium expression profiles from progressing stages of collagen-induced arthritis (CIA) were classified into six distinct groups using k-means clustering. Using an algorithm based on local over-representation and comparative genomics, we identified putatively functional transcription factor-binding sites (TFBS) in TATA-dependent proximal-promoters. Applying a filter based on spacing between TATA box and transcription start site (TSS) combined with the presence of over-represented nuclear factor kappaB (NFkappaB), AP-1, or CCAAT/enhancer-binding protein beta (C/EBPbeta) sites, 382 candidate murine and human promoters were reduced to 66, corresponding to 45 genes. In vitro, 9 out of 10 computationally defined promoter regions conferred cytokine-inducible expression in murine cells and human synovial fibroblasts. Under these conditions, the serum amyloid A3 (Saa3) promoter showed the strongest transcriptional induction and strength. We applied this promoter for driving therapeutically efficacious levels of the interleukin-1 receptor antagonist (Il1rn) in a disease-regulated fashion. These results demonstrate the value of bioinformatics for guiding the selection of endogenous promoters for transcriptionally targeted gene therapy.

Orthopedic gene therapy in 2008

Orthopedic disorders, although rarely fatal, are the leading cause of morbidity and impose a huge socioeconomic burden. Their prevalence will increase dramatically as populations age and gain weight. Many orthopedic conditions are difficult to treat by conventional means; however, they are good candidates for gene therapy. Clinical trials have already been initiated for arthritis and the aseptic loosening of prosthetic joints, and the development of bone-healing applications is at an advanced, preclinical stage. Other potential uses include the treatment of Mendelian diseases and orthopedic tumors, as well as the repair and regeneration of cartilage, ligaments, and tendons. Many of these goals should be achievable with existing technologies. The main barriers to clinical application are funding and regulatory issues, which in turn reflect major safety concerns and the opinion, in some quarters, that gene therapy should not be applied to nonlethal, nongenetic diseases. For some indications, advances in nongenetic treatments have also diminished enthusiasm. Nevertheless, the preclinical and early clinical data are impressive and provide considerable optimism that gene therapy will provide straightforward, effective solutions to the clinical management of several common debilitating disorders that are otherwise difficult and expensive to treat.

Gene therapy of the rheumatic diseases: 1998 to 2008

During the decade since the launch of Arthritis Research, the application of gene therapy to the rheumatic diseases has experienced the same vicissitudes as the field of gene therapy as a whole. There have been conceptual and technological advances and an increase in the number of clinical trials. However, funding has been unreliable and a small number of high-profile deaths in human trials, including one in an arthritis gene therapy trial, have provided ammunition to skeptics. Nevertheless, steady progress has been made in a number of applications, including rheumatoid arthritis and osteoarthritis, Sjögren syndrome, and lupus. Clinical trials in rheumatoid arthritis have progressed to phase II and have provided the first glimpses of possible efficacy. Two phase I protocols for osteoarthritis are under way. Proof of principle has been demonstrated in animal models of Sjögren syndrome and lupus. For certain indications, the major technological barriers to the development of genetic therapies seem to have been largely overcome. The translational research necessary to turn these advances into effective genetic medicines requires sustained funding and continuity of effort.

Current status of gene therapy for rheumatoid arthritis

Gene therapy offers great possibilities for treating rheumatoid arthritis (RA). Traditional surgical and pharmaceutical methods of treating RA have met with limited therapeutic success and have failed to produce a cure, but the past several years have seen extensive progress toward development of a gene therapy for arthritis. Numerous vectors and therapeutic genes have been investigated in animal models of arthritis, and the potential of gene therapy to treat or manage RA has been demonstrated in several clinical studies. Gene therapy offers the possibility of overcoming many of the limitations of current biologic therapies by providing long-term, high-level localized expression of therapeutic genes, potentially in as little as a single dose. In this review, we explore the advances in gene therapy for RA and summarize the recent preclinical and clinical data. In addition, we provide an overview of vectors and targets for RA gene therapy.

Perspectives on the use of gene therapy for chronic joint diseases

Advances in molecular and cellular biology have identified a wide variety of proteins including targeted cytokine inhibitors, immunomodulatory proteins, cytotoxic mediators, angiogenesis inhibitors, and intracellular signalling molecules that could be of great benefit in the treatment of chronic joint diseases, such as osteo- and rheumatoid arthritis. Unfortunately, protein-based drugs are difficult to administer effectively. They have a high rate of turnover, requiring frequent readministration, and exposure in non-diseased tissue can lead to serious side effects. Gene transfer technologies offer methods to enhance the efficacy of protein-based therapies, enabling the body to produce these molecules locally at elevated levels for extended periods. The proof of concept of gene therapies for arthritis has been exhaustively demonstrated in multiple laboratories and in numerous animal models. This review attempts to condense these studies and to discuss the relative benefits and limitations of the methods proposed and to discuss the challenges toward translating these technologies into clinical realities.

In vivo delivery of lentiviral vectors expressing vasoactive intestinal peptide complementary DNA as gene therapy for collagen-induced arthritis

OBJECTIVE

Vasoactive intestinal peptide (VIP) has been shown to exert potent immunomodulatory activity, and the use of lentiviral vectors has been found to be an effective means of gene delivery. The present study was therefore undertaken to investigate the feasibility and efficiency of gene therapy using lentiviral vectors expressing VIP (LentiVIP) for the treatment of rheumatoid arthritis (RA).

METHODS

We evaluated the therapeutic potential of the gene therapy strategy in the collagen-induced arthritis (CIA) mouse model, administering the vectors at different phases of the disease. The inflammatory response was determined by measuring the levels of various inflammatory cytokines and chemokines in the joints and serum. The Th1-mediated response was evaluated by determining the proliferative response and cytokine profile of T cells stimulated with autoantigen.

RESULTS

A single intraperitoneal injection of LentiVIP was highly effective in treating CIA. Mice with established, severe arthritis showed complete regression of the disease. The therapeutic effect of LentiVIP was associated with widespread biodistribution of the vector and increased VIP levels, especially in joints and lymphoid organs, and was mediated through a striking reduction of the 2 deleterious components of the disease, i.e., the autoimmune response (self-reactive Th1 cell activity and autoantibody production) and the inflammatory response. LentiVIP treatment also induced the generation and/or activation of CD4+,CD25+,FoxP3+ Treg cells in arthritic mice.

CONCLUSION

Our findings show that in vivo administration of lentiviral vector expressing VIP produces one of the most potent therapeutic effects described so far in any animal model of RA. We propose that VIP gene transfer should be further investigated as a potential novel, effective treatment of RA and other chronic autoimmune disorders.

Gene therapy for arthritis

Arthritis is among the leading causes of disability in the developed world. There remains no cure for this disease and the current treatments are only modestly effective at slowing the disease's progression and providing symptomatic relief. The clinical effectiveness of current treatment regimens has been limited by short half-lives of the drugs and the requirement for repeated systemic administration. Utilizing gene transfer approaches for the treatment of arthritis may overcome some of the obstacles associated with current treatment strategies. The present review examines recent developments in gene therapy for arthritis. Delivery strategies, gene transfer vectors, candidate genes, and safety are also discussed.

Potential Use of Gene Transfer in Athletic Performance Enhancement

After only a short history of three decades from concept to practice, gene therapy has recently been shown to have potential to treat serious human diseases. Despite this success, gene therapy remains in the realm of experimental medicine, and much additional preclinical and clinical study will be necessary for proving the efficacy and safety of this approach in the treatment of diseases in humans. However, a potential complicating factor is that advances in gene transfer technology could be misused to enhance athletic performance in sports, in a practice termed "gene doping". Moreover, gene doping could be a precursor to a broader controversial agenda of human "genetic enhancement" with the potential for a significant long-term impact on society. This review addresses the possible ways in which knowledge and experience gained in gene therapy in animals and humans may be abused for enhancing sporting prowess. We provide an overview of recent progress in gene therapy, with potential application to gene doping and with the major focus on candidate performance-enhancement genes. We also discuss the current status of preclinical studies and of clinical trials that use these genes for therapeutic purposes. Current knowledge about the association between the natural "genetic make-up" of humans and their physical characteristics and performance potential is also presented. We address issues associated with the safety of gene transfer technologies in humans, especially when used outside a strictly controlled clinical setting, and the obstacles to translating gene transfer strategies from animal studies to humans. We also address the need for development and implementation of measures to prevent abuse of gene transfer technologies, and to pursue research on strategies for its detection in order to discourage this malpractice among athletes.

Application of a disease-regulated promoter is a safer mode of local IL-4 gene therapy for arthritis

The application of disease-regulated promoters in local gene therapy for rheumatoid arthritis potentiates the development of a sophisticated treatment that relies on a restricted and fine-tuned supply of biologicals. Although several studies have investigated regulated promoters for achieving effective transgene expression during arthritis, none have explored their potential for minimizing deleterious effects arising from constitutive overexpression of transgenes under naive conditions. Using naive and collagen-induced arthritic mice, we examined the applicability of a hybrid interleukin-1 enhancer/interleukin-6 proximal promoter for achieving efficacious murine interleukin-4 gene therapy under arthritic conditions, while minimizing interleukin-4-induced inflammation under naive conditions. We found strong upregulation of transgene expression in virally transduced knee joints under arthritic conditions compared to levels in naive animals. Besides its responsiveness, the promoter strength proved sufficient for generating therapeutically efficacious levels interleukin-4, as demonstrated by the successful protection against cartilage erosion in collagen-induced arthritis. Most importantly, promoter-mediated restriction of the potent chemotactic interleukin-4 in naive animals strongly reduced the amounts of inflammatory cell influx. This study suggests the suitability of the interleukin-1 enhancer/interleukin-6 proximal promoter for the development of a local gene therapy strategy for rheumatoid arthritis that requires fine-tuned and restricted expression of transgenes with a pleiotrophic nature.