Feasibility of adenovirus-mediated nonsurgical synovectomy in collagen-induced arthritis-affected rhesus monkeys

Gene Delivery to Joints by Intra-Articular Injection

Most forms of arthritis are incurable, difficult to treat, and a major cause of disability in Western countries. Better local treatment of arthritis is impaired by the pharmacokinetics of the joint that make it very difficult to deliver drugs to joints at sustained, therapeutic concentrations. This is especially true of biologic drugs, such as proteins and RNA, many of which show great promise in preclinical studies. Gene transfer provides a strategy for overcoming this limitation. The basic concept is to deliver cDNAs encoding therapeutic products by direct intra-articular injection, leading to sustained, endogenous synthesis of the gene products within the joint. Proof of concept has been achieved for both in vivo and ex vivo gene delivery using a variety of vectors, genes, and cells in several different animal models. There have been a small number of clinical trials for rheumatoid arthritis (RA) and osteoarthritis (OA) using retrovirus vectors for ex vivo gene delivery and adeno-associated virus (AAV) for in vivo delivery. AAV is of particular interest because, unlike other viral vectors, it is able to penetrate deep within articular cartilage and transduce chondrocytes in situ. This property is of particular importance in OA, where changes in chondrocyte metabolism are thought to be fundamental to the pathophysiology of the disease. Authorities in Korea have recently approved the world's first arthritis gene therapy. This targets OA by the injection of allogeneic chondrocytes that have been transduced with a retrovirus carrying transforming growth factor-β₁ cDNA. Phase III studies are scheduled to start in the United States soon. Meanwhile, two additional Phase I trials are listed on Clinicaltrials.gov , both using AAV. One targets RA by transferring interferon-β, and the other targets OA by transferring interleukin-1 receptor antagonist. The field is thus gaining momentum and promises to improve the treatment of these common and debilitating diseases.

An Evaluation of 20 Years of EU Framework Programme-Funded Immune-Mediated Inflammatory Translational Research in Non-Human Primates

Aging western societies are facing an increasing prevalence of chronic inflammatory and degenerative diseases for which often no effective treatments exist, resulting in increasing health-care expenditure. Despite high investments in drug development, the number of promising new drug candidates decreases. We propose that preclinical research in non-human primates can help to bridge the gap between drug discovery and drug prescription. Translational research covers various stages of drug development of which preclinical efficacy tests in valid animal models is usually the last stage. Preclinical research in non-human primates may be essential in the evaluation of new drugs or therapies when a relevant rodent model is not available. Non-human primate models for life-threatening or severely debilitating diseases in humans are available at the Biomedical Primate Research Centre (BPRC). These have been instrumental in translational research for several decades. In order to stimulate European health research and innovation from bench to bedside, the European Commission has invested heavily in access to non-human primate research for more than 20 years. BPRC has hosted European users in a series of transnational access programs covering a wide range of research areas with the common theme being immune-mediated inflammatory disorders. We present an overview of the results and give an account of the studies performed as part of European Union Framework Programme (EU FP)-funded translational non-human primate research performed at the BPRC. These data illustrate the value of translational non-human primate research for the development of new therapies and emphasize the importance of EU FP funding in drug development.

The significance of non-human primates as preclinical models of human arthritic disease

BACKGROUND

The broad immunological gap between inbred SPF-raised strains of mice and rats and the diverse rheumatoid arthritis (RA) patient population limits the predictive value of the existing disease models for clinical success of new therapies, in particular for those using highly specific biologicals.

OBJECTIVE

This review argues that because of their closer immunological and physiological proximity to patients, disease models in non-human primates (NHPs) may bridge this gap and help reduce the failure of many (± 80%) new therapies in clinical trials. In various research areas, NHPs are an accepted intermediate between disease models in rodents and the ultimate introduction for clinical use in patients. However, with the exception of transplantation, this is not the case for immune-mediated inflammatory disorders, such as RA, although useful preclinical models are being developed.

METHOD

The validity and use of the rhesus monkey model of collagen-induced arthritis as a preclinical RA model is reviewed. The discussion comprises present genetic and immunological aspects, biomarkers, and an overview of published preclinical therapy evaluations.

CONCLUSION

It is time to consider the use of NHPs with a greater evolutionary proximity to humans as models for preclinical evaluation of new human-specific drugs for arthritic disease.

New drug discovery strategies for rheumatoid arthritis: a niche for nonhuman primate models to address systemic complications in inflammatory arthritis

INTRODUCTION

Despite the tremendous advances made in the treatment of rheumatoid arthritis (RA), there is still excess mortality observed in RA patients, which is mainly caused by cardiovascular disease (CVD). Altered lipid metabolism plays a major role in the etiology of CVD. A second common complication observed in RA patients is anemia. Both conditions are serious, reduce quality of life and are undertreated.

AREAS COVERED

The authors postulate that there is a specific niche for nonhuman primate models of inflammatory arthritis to address these systemic complications that occur in RA. Furthermore, the authors postulate that these nonhuman primate models are a useful platform to unveil the mechanisms underlying dyslipidemia and anemia, which are responsible for the manifestation of these complications.

EXPERT OPINION

The presence of currently untreated systemic complications of RA, such as dyslipidemia and anemia, provides interesting opportunities to include these in the preclinical evaluation of new therapies. In the selection of relevant models for the evaluation of new treatments for RA or the identification of new targets for therapy, we postulate that nonhuman primates should be considered as a valid preclinical model. Because of their closer immunological and physiological proximity to humans, these models in nonhuman primates can be valuable for studying disease-related aspects that cannot be addressed in rodent models.

Getting arthritis gene therapy into the clinic

Gene transfer technologies enable the controlled, targeted and sustained expression of gene products at precise anatomical locations, such as the joint. In this way, they offer the potential for more-effective, less-expensive treatments of joint diseases with fewer extra-articular adverse effects. A large body of preclinical data confirms the utility of intra-articular gene therapy in animal models of rheumatoid arthritis and osteoarthritis. However, relatively few clinical trials have been conducted, only one of which has completed phase II. This article summarizes the status in 2010 of the clinical development of gene therapy for arthritis, identifies certain constraints to progress and suggests possible solutions.

Amelioration of experimental arthritis by a telomerase-dependent conditionally replicating adenovirus that targets synovial fibroblasts

OBJECTIVE

Synovial fibroblasts (SFs) play a pivotal role in the pathogenesis of rheumatoid arthritis (RA). It has been documented that the phenotype of rheumatoid synovium is similar, in many respects, to that of an aggressive tumor. In this study, a novel, genetically engineered adenovirus was designed to lyse SFs that exhibit high telomerase activity and p53 mutations, and its effects as a novel therapeutic strategy were assessed in an experimental arthritis model.

METHODS

An E1B-55-kd-deleted adenovirus driven by the human telomerase reverse transcriptase promoter was constructed (designated Ad.GS1). Cytolysis of SFs and productive replication of Ad.GS1 in the SFs of rats with collagen-induced arthritis (CIA), as well as the SFs of patients with RA (RASFs), were assessed in vitro and in vivo. Treatment responses, as well as the presence of disease-related cytokines and enzymes in the ankle joints, were determined in the murine model.

RESULTS

Ad.GS1 replicated in and induced cytolysis of human RASFs and SFs from arthritic rats, but spared normal fibroblasts. Bioluminescence imaging in vivo also demonstrated replication of Ad.GS1 in arthritic rat joints, but not in normal rat joints. Intraarticular administration of Ad.GS1 significantly reduced the ankle circumference, articular index scores, radiographic scores, and histologic scores and decreased the production of interleukin-1beta, matrix metalloproteinase 9, and prolyl 4-hydroxylase in rats with CIA compared with their control counterparts.

CONCLUSION

This study is the first to demonstrate the amelioration of arthritic symptoms by a novel, telomerase-dependent adenovirus in the rat CIA model, an experimental model that resembles human RA. In addition, the results suggest that because of its ability to induce cytolysis of SFs, this virus may be further explored as a therapeutic agent in patients with RA.

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.

Gene therapy and cement injection for restabilization of loosened hip prostheses

Loosening of orthopedic hip prostheses is an increasing health problem. In elderly patients with comorbidity,revision surgery may lead to high mortality rates. A less invasive surgical technique is therefore required to reduce these patient risks. To this end a percutaneous gene therapy approach was designed to destroy the periprosthetic loosening membrane, and enable refixing of the hip prosthesis with percutaneous bone cement injections under radiological guidance. In this phase 1/2 dose-escalating gene therapy clinical trial, 12 patients were treated. Toxicity and hip function variables were monitored up to 6 months posttreatment. All patients completed the study and no dose-limiting toxicity was observed. Improvement in walking distance, independence,and pain was demonstrated particularly in patients receiving 3 x 10(10) and 1 x 10(11) viral particles. Taken together, these data show that this gene therapy approach targeted at the interface membrane around a loosened hip prosthesis is a feasible treatment option for elderly patients for whom surgical intervention is not appropriate.

[Gene therapy for osteoarticular disorders]

Osteoarticular disorders are the major cause of disability in Europe and North America. It is estimated that rheumatoid arthritis affects 1 % of the population and that more than two third of people over age 55 develop osteoarthritis. Because there are no satisfactory treatments, gene therapy offers a new therapeutic approach. The delivery of cDNA encoding anti-arthritic proteins to articular cells has shown therapeutic efficacy in numerous animal models in vivo. Through the development and the experimental progresses that have been made for both rheumatoid arthritis and osteoarthritis, this review discusses the different gene therapy strategies available today and the safety issues with which they may be associated. Among the different vectors available today, adeno-associated virus seems the best candidate for a direct in vivo gene delivery approach for the treatment of joint disorders.

Preclinical models of arthritic disease in non-human primates

The costs for the development of new drugs have increased dramatically over the past 30 years. One of the main reasons for this increase is the low success rate of new drugs being approved for patient use, which is, in part, a consequence of the common use of rodent models for preclinical validation of efficacy. Especially in the development of biologicals, which are now successfully used in the treatment of rheumatoid arthritis, the selection of the right animal model is pivotal. Non-human primates could help to bridge the evolutionary gap between rodent models and human patients.

Arthrography in loosened hip prostheses. Assessment of possibilities for intra-articular therapy

BACKGROUND

Loosening is a major complication in prosthesis surgery. Less invasive alternatives to revision surgery are required to prevent and treat prosthesis loosening. Some experimental therapies investigating alternative treatments exploit the intra-articular space as a route of administration. For efficient, local delivery of therapeutic agents a contained joint space is required. Furthermore, the volume of the joint space determines the concentration of the therapeutic ingredient in the joint.

METHODS

A retrospective analysis of 221 hip arthrograms performed between 1994 and 2004 for diagnosis of prosthesis loosening was performed. All arthrograms were studied for leakage of contrast medium and the volume of injected contrast medium.

RESULTS

There was a contained joint in 164 arthrograms (74%). The volume in these hips was 31+/-12.7 ml. Male patients had a larger joint volume than female patients (P=0.019). There was no difference in containment and joint volume between hips with a primary and with a revised prosthesis.

CONCLUSIONS

For successful intra-articular therapy it is necessary that the injected agent remains in the jointspace. As leakage of contrast medium was shown in about a quarter of hips, this study shows that an arthrogram may be useful in the inclusion procedure for intra-articular studies to determine containment of the joint and also the volume that can be injected.

Technology Insight: gene transfer and the design of novel treatments for rheumatoid arthritis

Rheumatoid arthritis (RA) is a chronic inflammatory disease characterized by systemic inflammation and joint destruction. Novel therapies have emerged during the past decade, marking a new era in the treatment of RA. Meanwhile, in vivo and in vitro gene-transfer studies have provided valuable insights into mechanisms of disease pathogenesis. Advanced gene-delivery techniques and animal models promise further progress in RA research and the development of novel therapeutic strategies for this disease. In this article we provide an overview of the wide spectrum of potential targets that have been identified so far, discuss currently available gene-transfer methods, and outline the barriers that need to be overcome for these approaches to be successfully applied in daily practice.

Gene therapy for patients with rheumatoid arthritis

Gene therapy seeks either to supply a missing or dysfunctional gene or to ensure continuous long-lasting production of a therapeutic protein. Rheumatoid arthritis is a candidate for gene therapy, as the mechanisms leading to joint inflammation and destruction have been partly elucidated. Nevertheless, several crucial questions need to be addressed. Knowledge of the underlying pathophysiological mechanisms is needed to guide selection of the candidate gene. In the light of current data, TNF and IL-1 antagonists are generating interest. A choice must be made between a viral vector (adenovirus, retrovirus, adeno-associated virus) and a nonviral vector (naked DNA, administered by electrotransfer or in liposomes). Finally, the relative merits of intraarticular and systemic administration need to be considered. Safety is a primary concern. The transgene and/or vector may induce adverse effects. For instance, a transgene inserted within the host genome (when a retroviral vector is used) may induce a mutation. A number of vectors and transgenes induce immune responses. Numerous studies are ongoing to investigate the safety and efficacy of gene therapy strategies in experimental models of rheumatoid arthritis. These studies will have to be completed before further clinical trials of gene therapy in rheumatoid arthritis are considered.

Gene therapy as a therapeutic approach for the treatment of rheumatoid arthritis: innovative vectors and therapeutic genes

In recent years, significant progress has been made in the treatment of rheumatoid arthritis (RA). In addition to conventional therapy, novel biologicals targeting tumour necrosis factor-alpha have successfully entered the clinic. However, the majority of the patients still has some actively inflamed joints and some patients suffer from side-effects associated with the high systemic dosages needed to achieve therapeutic levels in the joints. In addition, due to of the short half-life of these proteins there is a need for continuous, multiple injections of the recombinant protein. An alternative approach might be the use of gene transfer to deliver therapeutic genes locally at the site of inflammation. Several viral and non-viral vectors are being used in animal models of RA. The first gene therapy trials for RA have already entered the clinic. New vectors inducing long-term and regulated gene expression in specific tissue are under development, resulting in more efficient gene transfer, for example by using distinct serotypes of viral vectors such as adeno-associated virus. This review gives an overview of some promising vectors used in RA research. Furthermore, several therapeutic genes are discussed that could be used for gene therapy in RA patients.

Elimination of rheumatoid synovium in situ using a Fas ligand 'gene scalpel'

Surgical synovectomy to remove the inflammatory synovium can temporarily ameliorate rheumatoid inflammation and delay the progress of joint destruction. An efficient medically induced programmed cell death (apoptosis) in the rheumatoid synovium might play a role similar to synovectomy but without surgical tissue damage. Gene transfer of Fas ligand (FasL) has increased the frequency of apoptotic cells in mouse and rabbit arthritic synovium. In this study, we investigated whether repeated FasL gene transfer could remove human inflammatory synovial tissue in situ and function as a molecular synovectomy. Briefly, specimens of human synovium from joint replacement surgeries and synovectomies of rheumatoid arthritis (RA) patients were grafted subcutaneously into male C.B-17 severe combined immunodeficiency (SCID) mice. Injections of a recombinant FasL adenovirus (Ad-FasL) into the grafted synovial tissue at the dosage of 10(11) particles per mouse were performed every two weeks. Three days after the fifth virus injection, the mice were euthanized by CO2 inhalation and the human synovial tissues were collected, weighed and further examined. Compared to the control adenovirus-LacZ (Ad-LacZ) and phosphate buffered saline (PBS) injected RA synovium, the Ad-FasL injected RA synovium was dramatically reduced in size and weight (P < 0.005). The number of both synoviocytes & mononuclear cells was significantly reduced. Interestingly, an approximate 15-fold increased frequency of apoptotic cells was observed in RA synovium three days after Ad-FasL injection, compared with control tissues. In summary, our in vivo investigation of gene transfer to human synovium in SCID mice suggests that repeated intra-articular gene transfer of an apoptosis inducer, such as FasL, may function as a 'gene scalpel' for molecular synovectomy to arrest inflammatory synovium at an early stage of RA.

Non-human primate models of experimental autoimmune encephalomyelitis: Variations on a theme

Despite years of intensive research into multiple sclerosis (MS) scientists have not yet succeeded in developing an absolute therapy for the treatment of this disabling disease of the human central nervous system. The wide immunological gap between inbred rodent strains and the heterogeneous human population is probably the single most important factor that hampers the translation of scientific principles developed in rodents into effective therapies for MS. Because of the closer immunological proximity to humans, non-human primates provide useful experimental models that may help to bridge this gap. Here we review the models of experimental autoimmune encephalomyelitis in rhesus macaques and common marmosets. We will discuss the salient points of the models and suggest how these may represent the spectrum of inflammatory demyelinating diseases of the central nervous system in humans.

Modeling human arthritic diseases in nonhuman primates

Models of rheumatoid arthritis (RA) in laboratory animals are important tools for research into pathogenic mechanisms and the development of effective, safe therapies. Rodent models (rats and mice) have provided important information about the pathogenic mechanisms. However, the evolutionary distance between rodents and humans hampers the translation of scientific principles into effective therapies. The impact of the genetic distance between the species is especially seen with treatments based on biological molecules, which are usually species-specific. The outbred nature and the closer anatomical, genetic, microbiological, physiological, and immunological similarity of nonhuman primates to humans may help to bridge the wide gap between inbred rodent strain models and the heterogeneous RA patient population. Here we review clinical, immunological and pathological aspects of the rhesus monkey model of collagen-induced arthritis, which has emerged as a reproducible model of human RA in nonhuman primates.

Gene therapy for autoimmune diseases: quo vadis?

Biological therapies using antibodies and cytokines are becoming widespread for the treatment of chronic inflammatory autoimmune diseases. However, these treatments have several limitations - such as expense, the need for repeated injections and unwanted side-effects - that can be overcome by genetic delivery. This review summarizes the ingenuity, sophistication and variety of gene-therapy approaches that have been taken in the design of therapeutic molecules and vectors, the engineering of cells and the regulation of gene expression for the targeting of disease outcome. We focus our attention on multiple sclerosis, type 1 diabetes and rheumatoid arthritis.

Gene therapy in animal models of rheumatoid arthritis: are we ready for the patients?

Rheumatoid arthritis (RA) is a chronic inflammatory disease of the synovial joints, with progressive destruction of cartilage and bone. Anti-tumour necrosis factor-α therapies (e.g. soluble tumour necrosis factor receptors) ameliorate disease in 60–70% of patients with RA. However, the need for repeated systemic administration of relatively high doses in order to achieve constant therapeutic levels in the joints, and the reported side effects are downsides to this systemic approach. Several gene therapeutic approaches have been developed to ameliorate disease in animal models of arthritis either by restoring the cytokine balance or by genetic synovectomy. In this review we summarize strategies to improve transduction of synovial cells, to achieve stable transgene expression using integrating viruses such as adeno-associated viruses, and to achieve transcriptionally regulated expression so that drug release can meet the variable demands imposed by the intermittent course of RA. Evidence from animal models convincingly supports the application of gene therapy in RA, and the feasibility of gene therapy was recently demonstrated in phase I clinical trials.

Gene therapy for arthritis

Rheumatoid arthritis is an autoimmune disease with intra-articular inflammation and synovial hyperplasia that results in progressive degradation of cartilage and bone, in severe cases it causes systemic complications. Recently, biological agents that suppress the activities of proinflammatory cytokines have shown efficacy as antiarthritic drugs, but require frequent administration. Thus, gene transfer approaches are being developed as an alternative approach for targeted, more efficient and sustained delivery of inhibitors of inflammatory cytokines as well as other therapeutic agents. Indeed, the efficacy of gene transfer for the treatment of arthritis has been demonstrated in mouse, rat, rabbit, and horse models of disease whereas the feasibility of the approach has been demonstrated in Phase I clinical trials. In this review, the current status of both preclinical and clinical arthritis gene therapy is presented. In addition, the advantages and disadvantages of different types of vectors, target cells and therapeutic genes being developed for the treatment of arthritis are summarized. Finally, the future directions of the rapidly developed field of arthritis gene therapy are outlined.

Gene therapy in nonhuman primate models of human autoimmune disease

Before autoimmune diseases in humans can be treated with gene therapy, the safety and efficacy of the used vectors must be tested in valid experimental models. Monkeys, such as the rhesus macaque or the common marmoset, provide such models. This publication reviews the state of the art in monkey models for rheumatoid arthritis and multiple sclerosis and the (few) gene therapy experiments that have been performed in these models.

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.

Production of inflammatory mediators by renal epithelial cells is insensitive to glucocorticoids

1. In the present study we investigated the effect of glucocorticoids on the activation of renal tubular epithelial cells, which are thought to play an important role in inflammatory processes in the kidney. 2. Activation of renal epithelial cells by IL-1, TNF-alpha or CD40L resulted in increased production of cytokines and chemokines. Both in the renal epithelial cell line HK-2 and in primary cultures of human proximal tubular epithelial cells (PTEC) production of IL-6, IL-8 and monocyte chemotactic protein 1 (MCP-1) was not inhibited by glucocorticoids, independent of the stimulus. 3. In contrast, dexamethasone strongly inhibited cytokine production by immortalized renal fibroblasts and an airway epithelial cell line (A549). 4. Stimulation of renal epithelial cells resulted in activation of NF-kappaB, a pivotal transcription factor in the regulation of cytokine genes, as was shown by IkappaB-alpha degradation and increased DNA-binding activity. In contrast to dexamethasone, addition of the NF-kappaB inhibitors pyrrolidine dithiocarbamate (PDTC) and n-tosyl-l-phenylalanine chloromethyl ketone (TPCK) completely abolished cytokine and chemokine production. 5. Renal epithelial cells express abundant levels of the functional glucocorticoid receptor alpha (GRalpha) isoform and low levels of the inhibitory beta isoform (GRbeta). 6. In conclusion, cytokine production by renal epithelial cells is insensitive to the inhibitory effects of glucocorticoids. The lack of dexamethasone-mediated inhibition was specific for renal epithelial cells and could not be explained by an increased expression of the glucocorticoid receptor beta isoform.

Gene therapy in rheumatic diseases

Rheumatoid arthritis (RA) is a chronic inflammatory disease characterized by joint inflammation as well as progressive cartilage and bone destruction. Advances in the understanding of the pathophysiology of RA have led to the development of new therapeutic strategies, including gene therapy. Gene therapy offers a new approach to deliver therapeutic proteins to the joints of arthritis patients. Local as well as systemic gene therapy can be envisaged for the treatment of arthritis. Several viral and non-viral vectors have been used in animal models for rheumatoid arthritis for ex vivo and in vivo delivery of therapeutic genes. Promising pre-clinical data have resulted from the application of these strategies. Using ex vivo gene delivery, successful and safe gene transfer has been demonstrated in the joints of RA patients. Although new insights into the role of cytokines and other mediators of chronic inflammation have provided novel targets for therapeutic intervention, the development of vectors that induce long-term and regulated gene expression remains a challenge.

Fibroblast-mediated delivery of growth factor complementary DNA into mouse joints induces chondrogenesis but avoids the disadvantages of direct viral gene transfer

OBJECTIVE

To assess the advantages and disadvantages of a direct adenoviral and a cell-mediated approach to the induction of cartilage formation in joints by transfer of growth factor genes.

METHODS

Adenoviral vectors carrying insulin-like growth factor 1 (IGF-1) or bone morphogenetic protein 2 (BMP-2) complementary DNA were constructed and applied to primary human and murine chondrocytes or fibroblasts. Transgene expression was quantified by enzyme-linked immunosorbent assay. Direct injection of these vectors or AdLacZ, a reporter gene vector, into mouse knee joints was compared with the transplantation of syngeneic fibroblasts (infected ex vivo with the same vectors) with respect to virus spread, immune response, and cartilage formation by use of histologic, immunohistochemical, and molecular analyses.

RESULTS

AdIGF-1 and AdBMP-2 efficiently infected all cell types tested. Human cells secreted biologically relevant levels of protein over a period of at least 28 days. Direct transfer of AdLacZ into mouse knee joints resulted in positively stained synovial tissues, whereas AdLacZ-infected fibroblasts settled on the surface of the synovial membranes. Inadvertent spread of vector DNA into the liver, lung, and spleen was identified by nested polymerase chain reaction in all mice that had received the vector directly; this rarely occurred following fibroblast-mediated gene transfer. Direct injection of AdBMP-2 induced the synthesis of new cartilage in periarticular mesenchyme, accompanied by extensive osteophyte formation. When AdBMP-2 was administered by injecting ex vivo-infected fibroblasts, cartilage formation was observed only in regions near the injected cells. AdIGF-1 treatment did not lead to morphologic changes. Importantly, fibroblast-mediated gene transfer avoided the strong immune response to adenovirus that was elicited following direct application of the vector.

CONCLUSION

Our results indicate that cell-mediated gene transfer provides sufficient BMP-2 levels in the joint to induce cartilage formation while avoiding inadvertent vector spread and immune reactions.

Direct gene delivery strategies for the treatment of rheumatoid arthritis

Gene therapy offers a novel and innovative approach to the delivery of therapeutic proteins to the joints of patients with arthritis. Several viral vectors, including adenovirus, adeno-associated virus, retrovirus and herpes simplex virus, are capable of delivering exogenous cDNAs to the synovial lining, enabling effective levels of intra-articular transgene expression following direct injection to the joint. The expression of certain gene products has proven to be sufficient to inhibit the progression of disease in animals with experimental arthritis. Non-viral methods of gene transfer, however, are less satisfactory, and are limited by toxicity and transience of expression. Although the principle of direct gene delivery to the joint has been demonstrated, maintaining persistent intra-articular transgene expression remains a challenge.

Infection efficiency of type 5 adenoviral vectors in synovial tissue can be enhanced with a type 16 fiber

OBJECTIVE

To obtain an adenoviral vector with increased infection efficiency in the synovial tissue compared with conventional vectors based on adenovirus serotype 5 (Ad5), without compromising the specificity of infection.

METHODS

Coxsackie adenovirus receptor (CAR) expression was assessed in cultured synoviocytes. Chimeric adenoviruses based on Ad5 but carrying the DNA encoding the fiber of adenovirus from subgroup B (Adll, 16, 35) or D (Ad24, 28, 33, 45, or 47) were constructed and produced on PER.C6 cells. The gene transfer efficiency of these chimera was tested on cultured synoviocytes and peripheral blood mononuclear cells (PBMC).

RESULTS

No surface expression of CAR protein was observed on synoviocytes. CAR messenger RNA expression of synoviocytes was found to be low. Of all fiber chimeric vectors tested, vectors carrying the fiber of Ad16 (Ad5.fib16) were most potent, yielding approximately150 times increased transgene expression in cultured synoviocytes compared with those of Ad5. Flow cytometry showed that the increase in transgene expression was caused by the transduction of higher percentages of synoviocytes and higher gene expression per synoviocyte. Experiments with 500 virus particles/cell of Ad5.GFP or Ad5.fib16.GFP resulted in an infection efficiency of 0.6% and 1% in PBMC and 43% and 76% in synoviocytes, respectively.

CONCLUSION

Synoviocytes hardly express CAR, which hampers Ad5-mediated gene transfer. Ad5.fib16 is superior to Ad5 vectors for transducing synoviocytes, without compromising the specificity of infection. Our data suggest that Ad5.fib16-mediated gene transfer to synovial tissue improves the therapeutic window.

Gene therapy for rheumatoid arthritis

Rheumatoid arthritis (RA) is a painful chronic disorder. Conventional therapies are palliative, not curative. Advances in the understanding of the pathophysiology of RA have led to the development of new therapeutic strategies, including gene therapy. Multiple studies in several different animal models provide proof supporting the use of gene therapy in arthritis. A phase I clinical trial has already been performed successfully on nine women with end-stage RA in the United States, and two other trials are in progress. Limited duration of gene expression impedes the development of a clinically useful genetic treatment for arthritis.

Future of adenoviruses in the gene therapy of arthritis

Recombinant adenoviruses are straightforward to produce at high titres, have a promiscuous host-range, and, because of their ability to infect nondividing cells, lend themselves to in vivo gene delivery. Such advantages have led to their widespread and successful use in preclinical studies of arthritis gene therapy. While adenoviral vectors are well suited to 'proof of principle' experiments in laboratory animals, there are several barriers to their use in human studies at this time. Transient transgene expression limits their application to strategies, such as synovial ablation, which do not require extended periods of gene expression. Moreover, there are strong immunological barriers to repeat dosing. In addition, safety concerns predicate local, rather than systemic, delivery of the virus. Continued engineering of the adenoviral genome is producing vectors with improved properties, which may eventually overcome these issues. Promising avenues include the development of 'gutted' vectors encoding no endogenous viral genes and of adenovirus-AAV chimeras. Whether these will offer advantages over existing vectors, which may already provide safe, long-term gene expression following in vivo delivery, remains to be seen.

The influence of synovial fluid on adenovirus-mediated gene transfer to the synovial tissue

OBJECTIVE

To determine the effect of synovial fluid (SF) from rheumatoid arthritis (RA) patients on adenovirus type 5 (Ad5)-mediated gene transfer to synoviocytes, and to explore new strategies for vector development based on the neutralization data obtained.

METHODS

SF was derived from 63 randomly selected R4 patients. Ten samples were used to study the effect of SF on Ad5-mediated gene transfer in synoviocytes. IgG and <100-kd fractions were purified from these 10 SF, and their effect on gene transfer was determined. Neutralizing activity against wild-type Ad5 (wt-Ad5), wt-Ad26, wt-Ad34, wt-Ad35, and wt-Ad48 was tested in the SF from the remaining 53 patients.

RESULTS

Seven of 10 SF samples inhibited Ad5-mediated gene transfer. Purified antibodies exhibited inhibition patterns similar to those seen with unfractionated SF. In 5 of 10 SF samples, low molecular weight fractions inhibited gene transfer at low dilutions. Neutralization of wt-Ad35 by SF from RA patients was less frequent than neutralization of other wt-Ad tested (4% versus 42-72%; n = 53).

CONCLUSION

SF from 70% of the RA patients contained neutralizing antibodies that hamper Ad5-mediated gene transfer to synoviocytes. The activity of neutralizing antibodies may be circumvented in the majority of RA patients when vectors based on an Ad35 backbone are used.

Interleukin-17 and CD40-ligand synergistically enhance cytokine and chemokine production by renal epithelial cells

Renal allograft rejection is characterized by an influx of inflammatory cells. Interaction between infiltrating T cells and resident parenchymal cells might play an important role in the ongoing inflammatory response. The present study demonstrates that CD40L, a product of activated T cells, is locally expressed in kidneys undergoing rejection. Furthermore, during rejection, CD40 expression not only is present on most graft infiltrating cells but also is increased on resident tubular epithelial cells (TEC). To obtain more detailed insight in the consequences of T cell/TEC interaction, we analyzed the production of chemokines, including interleukin-8 (IL-8), monocyte chemoattractant protein-1 (MCP-1) and regulated upon activation, normal T cell expressed and secreted (RANTES), and the production of IL-6 by cultured human primary TEC in response to activation with CD40L in vitro. In addition, we studied the interaction with IL-17, a T-cell-specific cytokine previously demonstrated to be present during renal allograft rejection. The results, obtained by enzyme-linked immunosorbent assay, indicate that simultaneous activation of TEC with IL-17 and CD40L synergistically enhances production of IL-6 (2.1-fold higher than sum of single stimulations) and the chemokines IL-8 (15-fold) and RANTES (5.8-fold) as demonstrated by statistical analysis (P: < 0.05), whereas effects on MCP-1 (1.4-fold) are additive. Part of the synergy can be explained by increased CD40 expression on TEC upon IL-17 stimulation. The synergy is not unique for TEC, because similar responses were found with human synoviocytes and a foreskin fibroblast cell line (FS4). Stimulation of TEC with CD40L results in activation of NF-kappaB and induction of cytokine production by IL-17 and CD40L is prevented by addition of the NF-kappaB inhibitor pyrrolidine dithiocarbamate. These data suggest an important role for T cells in renal allograft rejection by acting on parenchymal cells via both soluble mediators and direct cellular contact.

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

Immunomodulation of autoimmune inflammatory diseases like rheumatoid arthritis can be achieved by anti-inflammatory T2 cytokines such as interleukin (IL)-4 administered by gene therapy. In this study we investigated the efficiency of adeno-associated viruses (AAV) vectors in collagen-induced arthritis (CIA). After injection of AAV-LacZ in the tarsus area of mice, the expression of the transgene was localized in the deep muscles cells near the bone. LacZ expression was found in liver, heart and lung after i.m. injection of AAV-LacZ, showing a spread of the vector over the body. Anti-AAV neutralizing antibodies were detected in the serum after i.m. injection of AAV-LacZ, but they did not alter the transgene expression after re-administration of AAV-LacZ. Long-term IL-4 expression persisted 129 days after intra-muscular injection of 3.7 x 10(10) or 11.2 x 10(10) AAV-IL-4 p.p. (average 7.7 or 17.5 pg IL-4/mg proteins, respectively). More importantly, the treatment of CIA with AAV-IL-4 vector in mice produced a therapeutic benefit, since we show a diminished prevalence of the disease, a significant reduction in paw swelling, attenuated histological synovitis and a 10 days delayed onset of arthritis. This is the first evidence that AAV vector-mediated gene therapy using a T2 cytokine is efficient in an animal model of rheumatoid arthritis.

Gene therapy for autoimmune disorders

Although many autoimmune disorders do not have a strong genetic basis, their treatment may nevertheless be improved by gene therapies. Most strategies seek to transfer genes encoding immunomodulatory products that will alter host immune responses in a beneficial manner. Used in this fashion, genes serve as biological delivery vehicles for the products they encode. By this means gene therapy overcomes obstacles to the targeted delivery of proteins and RNA, and improves their efficacy while providing a longer duration of effect, and, potentially, greater safety. Additional genetic strategies include DNA vaccination and the ablation of selected tissues and cell populations. There is considerable evidence from animal studies that gene therapies work: examples include the treatment of experimental models of rheumatoid arthritis, multiple sclerosis, diabetes, and lupus. Pre-clinical success in treating animal models of rheumatoid arthritis has led to the first clinical trial of gene therapy for an autoimmune disease. In this Phase I study, a cDNA encoding the interleukin-1 receptor antagonist was transferred to the knuckle joints of patients with advanced rheumatoid arthritis. Two additional clinical trials are in progress. It is likely that gene therapy will provide effective new treatments for a wide range of autoimmune disorders.

Adenoviral mediated delivery of FAS ligand to arthritic joints causes extensive apoptosis in the synovial lining

BACKGROUND

Rheumatoid arthritis (RA) is an autoimmune disease where the synovial lining layer of the joint becomes thickened, hypercellular, and highly aggressive. Invading synovial tissue erodes cartilage and subchondral bone and leads to loss of joint function. FasL, a cell-surface molecule on activated T-cells interacts with its receptor, Fas, to induce apoptosis in target cells. We addressed the feasibility of using adenoviral gene transfer of FasL therapeutically to mediate apoptosis in arthritic joints similar in size to the small joints of the hands and feet that are the primary sites of RA in humans.

METHODS

Adenoviral vectors were used to transfer FasL and LacZ cDNAs into human RA and rabbit synovial fibroblasts in culture where apoptosis was evaluated using MTT and TUNEL analyses. The ability of Ad.FasL to mediate synovial apoptosis in vivo was then addressed in an IL-1-induced arthritis model in the rabbit knee.

RESULTS

In culture, delivery of FasL was found to efficiently induce apoptosis in both human RA and rabbit synovial fibroblasts. The ability of Ad.FasL to induce synovial apoptosis was then evaluated in rabbit knee joints. 24 h after intra-articular injection of 10(11) Ad.FasL particles, large regions of synovial tissue were observed histologically consisting primarily of fibrous matrix and cellular debris. TUNEL staining of corresponding sections was highly positive for fragmented DNA. Glycosaminoglycan (GAG) synthesis from cartilage shavings from treated joints suggests that Ad.FasL does not induce significant apoptosis in resident articular chondrocytes.

CONCLUSIONS

Infection of human and rabbit synovial fibroblasts with Ad.FasL results in significant apoptotic cell death in vitro. Direct intra-articular injection of Ad.FasL in the arthritic rabbit knee results in extensive apoptosis in the synovium without affecting chondrocyte viability.

Macrophages in rheumatoid arthritis

The abundance and activation of macrophages in the inflamed synovial membrane/pannus significantly correlates with the severity of rheumatoid arthritis (RA). Although unlikely to be the 'initiators' of RA (if not as antigen-presenting cells in early disease), macrophages possess widespread pro-inflammatory, destructive, and remodeling capabilities that can critically contribute to acute and chronic disease. Also, activation of the monocytic lineage is not locally restricted, but extends to systemic parts of the mononuclear phagocyte system. Thus, selective counteraction of macrophage activation remains an efficacious approach to diminish local and systemic inflammation, as well as to prevent irreversible joint damage.