Local gene delivery of heme oxygenase-1 by adeno-associated virus into osteoarthritic mouse joints exhibiting synovial oxidative stress

Rationally engineered novel AAV capsids for intra-articular gene delivery

Intra-articular adeno-associated virus (AAV) gene therapy has been explored as a potential strategy for joint diseases. However, concerns of low transduction efficacy, off-target expression, and neutralizing antibodies (Nabs) still need to be addressed. In this study, we demonstrated that AAV6 was the best serotype to transduce joints after screening serotypes 1 to 9. To develop a more effective AAV vector, a set of novel AAV capsids were rationally engineered. The mutant AAV62 created by swapping variable region I (VRI) of AAV2 into AAV6 induced a higher transduction efficiency per AAV genome copy number. To further investigate the roles of specific amino acids in the transduction of AAV62 and AAV6, we found out that AAV6D with the deletion of threonine at residue 265 induced a 2-fold higher transduction than AAV6, while the transduction efficiency from AAV6M with the mutation of alanine to glutamine at residue 263 was 10-fold lower. AAV6D efficiently transduced both synoviocytes and chondrocytes with low AAV genome copy numbers in other tissues and less Nab formation. This study demonstrates that novel AAV mutants with rational engineering may enhance joint transduction after intra-articular administration in mice, with the potential to evade AAV Nabs and minimize off-target effects in the liver.

Osteoarthritis gene therapy in 2022

PURPOSE OF REVIEW

To assess the present status of gene therapy for osteoarthritis (OA).

RECENT FINDINGS

An expanding list of cDNAs show therapeutic activity when introduced into the joints of animals with experimental models of OA. In vivo delivery with adenovirus or adeno-associated virus is most commonly used for this purpose. The list of encoded products includes cytokines, cytokine antagonists, enzymes, enzyme inhibitors, growth factors and noncoding RNA. Elements of CRISPR-Cas have also been delivered to mouse knees to ablate key genes. Several human trials have been initiated, using transgenes encoding transforming growth factor-β1, interleukin-1 receptor antagonist, interferon-β, the NKX3.2 transcription factor or variant interleukin-10. The first of these, using ex vivo delivery with allogeneic chondrocytes, gained approval in Korea which was subsequently retracted. However, it is undergoing Phase III clinical trials in the United States. The other trials are in Phase I or II. No gene therapy for OA has current marketing approval in any jurisdiction.

SUMMARY

Extensive preclinical data support the use of intra-articular gene therapy for treating OA. Translation is beginning to accelerate and six gene therapeutics are in clinical trials. Importantly, venture capital has begun to flow and at least seven companies are developing products. Significant progress in the future can be expected.

CEMIP (KIAA1199) regulates inflammation, hyperplasia and fibrosis in osteoarthritis synovial membrane

Osteoarthritis (OA) synovial membrane is mainly characterized by low-grade inflammation, hyperplasia with increased cell proliferation and fibrosis. We previously underscored a critical role for CEMIP in fibrosis of OA cartilage. However, its role in OA synovial membrane remains unknown. An in vitro model with fibroblast-like synoviocytes from OA patients and an in vivo model with collagenase-induced OA mice were used to evaluate CEMIP-silencing effects on inflammation, hyperplasia and fibrosis. Our results showed that i. CEMIP expression was increased in human and mouse inflamed synovial membrane; ii. CEMIP regulated the inflammatory response pathway and inflammatory cytokines production in vitro and in vivo; iii. CEMIP induced epithelial to mesenchymal transition pathway and fibrotic markers in vitro and in vivo; iv. CEMIP increased cell proliferation and synovial hyperplasia; v. CEMIP expression was increased by inflammatory cytokines and by TGF-β signaling; vi. anti-fibrotic drugs decreased CEMIP expression. All these findings highlighted the central role of CEMIP in OA synovial membrane development and underscored that targeting CEMIP could be a new therapeutic approach.

Cellular and Tissue Selectivity of AAV Serotypes for Gene Delivery to Chondrocytes and Cartilage

Background: Despite several studies on the effect of adeno-associated virus (AAV)-based therapeutics on osteoarthritis (OA), information on the transduction efficiency and applicable profiles of different AAV serotypes to chondrocytes in hard cartilage tissue is still limited. Moreover, the recent discovery of additional AAV serotypes makes it necessary to screen for more suitable AAV serotypes for specific tissues. Here, we compared the transduction efficiencies of 14 conventional AAV serotypes in human chondrocytes, mouse OA models, and human cartilage explants obtained from OA patients. Methods: To compare the transduction efficiency of individual AAV serotypes, green fluorescent protein (GFP) expression was detected by fluorescence microscopy or western blotting. Likewise, to compare the transduction efficiencies of individual AAV serotypes in cartilage tissues, GFP expression was determined using fluorescence microscopy or immunohistochemistry, and GFP-positive cells were counted. Results: Only AAV2, 5, 6, and 6.2 exhibited substantial transduction efficiencies in both normal and OA chondrocytes. All AAV serotypes except AAV6 and rh43 could effectively transduce human bone marrow mesenchymal stem cells. In human and mouse OA cartilage tissues, AAV2, AAV5, AAV6.2, AAV8, and AAV rh39 showed excellent tissue specificity based on transduction efficiency. These results indicate the differences in transduction efficiencies of AAV serotypes between cellular and tissue models. Conclusions: Our findings indicate that AAV2 and AAV6.2 may be the best choices for AAV-mediated gene delivery into intra-articular cartilage tissue. These AAV vectors hold the potential to be of use in clinical applications to prevent OA progression if appropriate therapeutic genes are inserted into the vector.

Pharmacological Targeting of Heme Oxygenase-1 in Osteoarthritis

Osteoarthritis (OA) is a common aging-associated disease that clinically manifests as joint pain, mobility limitations, and compromised quality of life. Today, OA treatment is limited to pain management and joint arthroplasty at the later stages of disease progression. OA pathogenesis is predominantly mediated by oxidative damage to joint cartilage extracellular matrix and local cells such as chondrocytes, osteoclasts, osteoblasts, and synovial fibroblasts. Under normal conditions, cells prevent the accumulation of reactive oxygen species (ROS) under oxidatively stressful conditions through their adaptive cytoprotective mechanisms. Heme oxygenase-1 (HO-1) is an iron-dependent cytoprotective enzyme that functions as the inducible form of HO. HO-1 and its metabolites carbon monoxide and biliverdin contribute towards the maintenance of redox homeostasis. HO-1 expression is primarily regulated at the transcriptional level through transcriptional factor nuclear factor erythroid 2 (NF-E2)-related factor 2 (Nrf2), specificity protein 1 (Sp1), transcriptional repressor BTB-and-CNC homology 1 (Bach1), and epigenetic regulation. Several studies report that HO-1 expression can be regulated using various antioxidative factors and chemical compounds, suggesting therapeutic implications in OA pathogenesis as well as in the wider context of joint disease. Here, we review the protective role of HO-1 in OA with a focus on the regulatory mechanisms that mediate HO-1 activity.

Berberine-mediated up-regulation of surfactant protein D facilitates cartilage repair by modulating immune responses via the inhibition of TLR4/NF-ĸB signaling

The innate immune system drives inflammatory joint damage in osteoarthritis (OA) and regulates cartilage repair. Berberine chloride (BBR) is an isoquinoline alkaloid that shows immunomodulatory activity in a variety of cell lines. However, the immunomodulatory mechanisms of BBR in chondrocytes during OA are largely unknown. Herein, we assessed the ability of BBR to mediate chondroprotection through its effects on innate immunity. We found that BBR up-regulated the expression of surfactant protein D (SP-D) in OA cartilage, a key regulator of inflammation and innate immunity both in the airways and extrapulmonary tissues, including joint cartilage. To further explore these findings, we used recombinant adeno-associated virus (rAAV)-mediated knockdown of SP-D. Silencing was assessed in rat model of surgically-induced OA in the presence or absence of BBR treatment, 10 weeks post-surgery. We observed a clear improvement in histological scores of BBR-treated animals compared to those treated with BBR and the rAAV-SP-D vector. In addition, animals co-treated with BBR + recombinant human SP-D (rhSP-D) exhibited significantly lower histological scores than those treated with BBR alone. BBR treatment led to significantly reduced immune cell infiltration mediated through TLR4, F4/80, CD68 and CD34, whilst SP-D silencing reversed this improvement. In contrast, rhSP-D treatment enhanced the protective phenotype. We further explored how BBR influences SP-D and other OA-associated genes in vitro. We observed an up-regulation of SP-D and a marked decline in TRAF6, TLR4, MD-2 and MyD88 expression, as well as NF-κB p65 and IκBα phosphorylation in chondrocytes treated with sodium nitroprusside. siRNAs specific for SP-D were able to partially reverse this phenotype, whilst both rhSP-D and the TLR4 inhibitor TAK-242 enhanced the effects. Together, these results are consistent with a model wherein SP-D has therapeutic potential for OA treatment. Concomitantly, BBR modulates immune responses and decreases cartilage degradation. These findings suggest that BBR achieves this function through releasing SP-D from MD2/SP-D complexes and through the inhibition of TLR4/NF-κB signaling.

Bioactive factors for cartilage repair and regeneration: Improving delivery, retention, and activity

Articular cartilage is a remarkable tissue whose sophisticated composition and architecture allow it to withstand complex stresses within the joint. Once injured, cartilage lacks the capacity to self-repair, and injuries often progress to joint wide osteoarthritis (OA) resulting in debilitating pain and loss of mobility. Current palliative and surgical management provides short-term symptom relief, but almost always progresses to further deterioration in the long term. A number of bioactive factors, including drugs, corticosteroids, and growth factors, have been utilized in the clinic, in clinical trials, or in emerging research studies to alleviate the inflamed joint environment or to promote new cartilage tissue formation. However, these therapies remain limited in their duration and effectiveness. For this reason, current efforts are focused on improving the localization, retention, and activity of these bioactive factors. The purpose of this review is to highlight recent advances in drug delivery for the treatment of damaged or degenerated cartilage. First, we summarize material and modification techniques to improve the delivery of these factors to damaged tissue and enhance their retention and action within the joint environment. Second, we discuss recent studies using novel methods to promote new cartilage formation via biofactor delivery, that have potential for improving future long-term clinical outcomes. Lastly, we review the emerging field of orthobiologics, using delivered and endogenous cells as drug-delivering "factories" to preserve and restore joint health. Enhancing drug delivery systems can improve both restorative and regenerative treatments for damaged cartilage. STATEMENT OF SIGNIFICANCE: Articular cartilage is a remarkable and sophisticated tissue that tolerates complex stresses within the joint. When injured, cartilage cannot self-repair, and these injuries often progress to joint-wide osteoarthritis, causing patients debilitating pain and loss of mobility. Current palliative and surgical treatments only provide short-term symptomatic relief and are limited with regards to efficiency and efficacy. Bioactive factors, such as drugs and growth factors, can improve outcomes to either stabilize the degenerated environment or regenerate replacement tissue. This review highlights recent advances and novel techniques to enhance the delivery, localization, retention, and activity of these factors, providing an overview of the cartilage drug delivery field that can guide future research in restorative and regenerative treatments for damaged cartilage.

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.

Resveratrol ameliorates inflammatory damage and protects against osteoarthritis in a rat model of osteoarthritis

Resveratrol is a non-flavonoid polyphenol compound with a stilbene structure. As a type of phytoalexin produced under stress in plants, it improves the plant's resistance against pathogens and environment deterioration, and performs important functions beneficial to human health, such as anti-cancer, anti-oxidation, regulating blood lipid levels and prolonging life span. The effects of resveratrol were examined in a rat model of osteoarthritis (OA) and observed to ameliorate inflammatory damage and protect against OA. In the present study, resveratrol significantly inhibited the induction of clinical scores in rats with OA. Resveratrol inhibited tumor necrosis factor-α, interleukin (IL)-1β, IL-6 and IL-18 expression levels, and decreased caspase-3/9 activity in rats with OA. Inducible nitric oxide synthase, nuclear factor (NF)-κB, phosphorylated-(p)-AMP-activated protein kinase and sirtuin 1 protein expression were significantly suppressed and heme oxygenase 1 (HO-1) and nuclear factor erythroid 2-related factor 2 (Nrf-2) protein expression was stimulated in rats with OA treated with resveratrol. The current results indicate that resveratrol ameliorates inflammatory damage and protects against OA in a rat model of OA via NF-κB and HO-1/Nrf-2 signaling.

New herbal composition (OA-F2) protects cartilage degeneration in a rat model of collagenase induced osteoarthritis

BACKGROUND

Prevalence of osteoarthritis (OA) is on rise on the global scale. At present there are no satisfactory pharmacological agents for treating OA. Our previous study showed that Sida cordifolia L. and Zingiber officinale Rosc. had protective effect on cartilage. Here, we describe the effect of OA-F2, a herbal formulation prepared using combination of these two plants in alleviating OA associated symptoms in a rat model of collagenase-induced OA.

METHODS

OA was induced by intra-articular injection of collagenase type II in wistar rats. Diclofenac (10 mg/kg) was used as a reference control. Rats (n = 6) were divided into 6 groups: Healthy control (HC), osteoarthritic control (OAC), diclofenac (DICLO), OA-F2L (135 mg/kg), OA-F2M (270 mg/kg) and OA-F2H (540 mg/kg). The effects of the 20 days treatment were monitored by parameters like knee diameter, paw volume, paw retraction; serum C-reactive protein (CRP), alkaline phosphatase (ALP) and glycosaminoglycan (GAG). Radiography and histopathology of knee joint were also studied. Additionally, gene expression was studied from isolated synovium tissue proving anti-osteoarthritic potential of OA-F2.

RESULTS

Oral administration of OA-F2 has significantly prevented knee swelling compared to OAC; OA-F2 and DICLO, significantly reduced paw volume compared to OAC. Paw latency was remarkably increased by OA-F2 compared to OAC. OA-F2L (-0.670, p < 0.001), M (-0.110, p < 0.05) and H (0.073) has markedly reduced levels of CRP compared to DICLO. OA-F2L (p < 0.05), M (p < 0.001) and H (p < 0.05) significantly reduced ALP levels, compared to DICLO. GAG release in the serum was also significantly lowered in OA-F2 treated group compared to DICLO. Radiological and histopathological observations showed cartilage protection by OA-F2. OA-F2 has upregulated SOD and GPx. Upregulated CAT expression was observed in OA-F2M and H. Considerable down-regulation of expression of MMP-3 and MMP-9 was observed in all the groups. Up-regulation of TIMP-1 was observed in rats treated with OA-F2L, H and DICLO.

CONCLUSION

OA-F2 has shown therapeutic effects in rat model of collagenase induced OA by demonstrating cartilage protection through controlling MMPs and improving anti-oxidant levels in arthritic synovium and is a potent candidate for further drug development and treatment for OA.