Application of inflammation‐responsive promoter for an in vitro arthritis model

Engineering approaches for RNA-based and cell-based osteoarthritis therapies

Osteoarthritis (OA) is a chronic, debilitating disease that substantially impairs the quality of life of affected individuals. The underlying mechanisms of OA are diverse and are becoming increasingly understood at the systemic, tissue, cellular and gene levels. However, the pharmacological therapies available remain limited, owing to drug delivery barriers, and consist mainly of broadly immunosuppressive regimens, such as corticosteroids, that provide only short-term palliative benefits and do not alter disease progression. Engineered RNA-based and cell-based therapies developed with synthetic chemistry and biology tools provide promise for future OA treatments with durable, efficacious mechanisms of action that can specifically target the underlying drivers of pathology. This Review highlights emerging classes of RNA-based technologies that hold potential for OA therapies, including small interfering RNA for gene silencing, microRNA and anti-microRNA for multi-gene regulation, mRNA for gene supplementation, and RNA-guided gene-editing platforms such as CRISPR-Cas9. Various cell-engineering strategies are also examined that potentiate disease-dependent, spatiotemporally regulated production of therapeutic molecules, and a conceptual framework is presented for their application as OA treatments. In summary, this Review highlights modern genetic medicines that have been clinically approved for other diseases, in addition to emerging genome and cellular engineering approaches, with the goal of emphasizing their potential as transformative OA treatments.

The Role of Interleukin-4 and Interleukin-10 in Osteoarthritic Joint Disease: A Systematic Narrative Review

OBJECTIVE

A fusion protein of interleukin-4 and interleukin-10 (IL4-10 FP) was developed as a disease-modifying osteoarthritis drug (DMOAD), and chondroprotection, anti-inflammation, and analgesia have been suggested. To better understand the mechanisms behind its potential as DMOAD, this systematic narrative review aims to assess the potential of IL-4, IL-10 and the combination of IL-4 and IL-10 for the treatment of osteoarthritis. It describes the chondroprotective, anti-inflammatory, and analgesic effects of IL-4, IL-10, and IL4-10 FP.

DESIGN

PubMed and Embase were searched for publications that were published from 1990 until May 21, 2021 (moment of search). Key search terms were: Osteoarthritis, Interleukin-4, and Interleukin-10. This yielded 2,479 hits, of which 43 were included in this review.

RESULTS

IL-4 and IL-10 showed mainly protective effects on osteoarthritic cartilage in vitro and in vivo, as did IL4-10 FP. Both cytokines showed anti-inflammatory effects, but also proinflammatory effects. Only in vitro IL4-10 FP showed purely anti-inflammatory effects, indicating that proinflammatory effects of one cytokine can be counteracted by the other when given as a combination. Only a few studies investigated the analgesic effects of IL-4, IL-10 or IL4-10 FP. In vitro, IL-4 and IL4-10 FP were able to decrease pain mediators. In vivo, IL-4, IL-10, and IL4-10 FP were able to reduce pain.

CONCLUSIONS

In conclusion, this review describes overlapping, but also different modes of action for the DMOAD effects of IL-4 and IL-10, giving an explanation for the synergistic effects found when applied as combination, as is the case for IL4-10 FP.

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.

Designer Stem Cells: Genome Engineering and the Next Generation of Cell-Based Therapies

Stem cells provide tremendous promise for the development of new therapeutic approaches for musculoskeletal conditions. In addition to their multipotency, certain types of stem cells exhibit immunomodulatory effects that can mitigate inflammation and enhance tissue repair. However, the translation of stem cell therapies to clinical practice has proven difficult due to challenges in intradonor and interdonor variability, engraftment, variability in recipient microenvironment and patient indications, and limited therapeutic biological activity. In this regard, the success of stem cell-based therapies may benefit from cellular engineering approaches to enhance factors such as purification, homing and cell survival, trophic effects, or immunomodulatory signaling. By combining recent advances in gene editing, synthetic biology, and tissue engineering, the potential exists to create new classes of "designer" cells that have prescribed cell-surface molecules and receptors as well as synthetic gene circuits that provide for autoregulated drug delivery or enhanced tissue repair. Published by Wiley Periodicals, Inc. J Orthop Res 37:1287-1293, 2019.

Intra-articular drug delivery systems for joint diseases

Intra-articular (IA) injections directly deliver high concentrations of therapeutics to the joint space and are routinely used in various musculoskeletal conditions such as osteoarthritis (OA) and rheumatoid arthritis (RA). However, current IA-injected drugs are rapidly cleared and do not significantly affect the course of joint disease. In this review, we highlight recent developments in IA therapy, with a special emphasis on current and emerging therapeutic carriers and their potential to deliver disease-modifying treatment modalities for arthritis. Recent IA approaches concentrate on platforms that are safe with efficient tissue penetration, and readily translatable for controlled and sustained delivery of therapeutic agents. Gene therapy delivered by viral or non-viral vectors and cell-based therapy for cartilage preservation and regeneration are being intensively explored.

Inflammation-induced transgene expression in genetically engineered equine mesenchymal stem cells

BACKGROUND

Osteoarthritis, a chronic and progressive degenerative joint disorder, ranks amongst the top five causes of disability. Given the high incidence, associated socioeconomic costs and the absence of effective disease-modifying therapies of osteoarthritis, cell-based treatments offer a promising new approach. Owing to their paracrine, differentiation and self-renewal abilities, mesenchymal stem cells (MSCs) have great potential for regenerative medicine, which might be further enhanced by targeted gene therapy. Hence, the development of systems allowing transgene expression, particularly when regulated by natural disease-dependent occuring substances, is of high interest.

METHODS

Bone marrow-isolated equine MSCs were stably transduced with an HIV-1 based lentiviral vector expressing the luciferase gene under control of an inducible nuclear factor κB (NFκB)-responsive promoter. Marker gene expression was analysed by determining luciferase activity in transduced cells stimulated with different concentrations of interleukin (IL)-1β or tumour necrosis factor (TNF)α.

RESULTS

A dose-dependent increase in luciferase expression was observed in transduced MSCs upon cytokine stimulation. The induction effect was more potent in cells treated with TNFα compared to those treated with IL-1β. Maximum transgene expression was obtained after 48 h of stimulation and the same time was necessary to return to baseline luciferase expression levels after withdrawal of the stimulus. Repeated cycles of induction allowed on-off modulation of transgene expression without becoming refractory to induction. The NFκB-responsive promoter retained its inducibility also in chondrogenically differentiated MSC/Luc cells.

CONCLUSIONS

The results of the present study demonstrate that on demand transgene expression from the NFκB-responsive promoter using naturally occurring inflammatory cytokines can be induced in undifferentiated and chondrogenically differentiated equine MSCs. Copyright © 2016 John Wiley & Sons, Ltd.

Genome Engineering for Personalized Arthritis Therapeutics

Arthritis represents a family of complex joint pathologies responsible for the majority of musculoskeletal conditions. Nearly all diseases within this family, including osteoarthritis, rheumatoid arthritis, and juvenile idiopathic arthritis, are chronic conditions with few or no disease-modifying therapeutics available. Advances in genome engineering technology, most recently with CRISPR-Cas9, have revolutionized our ability to interrogate and validate genetic and epigenetic elements associated with chronic diseases such as arthritis. These technologies, together with cell reprogramming methods, including the use of induced pluripotent stem cells, provide a platform for human disease modeling. We summarize new evidence from genome-wide association studies and genomics that substantiates a genetic basis for arthritis pathogenesis. We also review the potential contributions of genome engineering in the development of new arthritis therapeutics.

3'-Sialyllactose protects against osteoarthritic development by facilitating cartilage homeostasis

3′‐Sialyllactose has specific physiological functions in a variety of tissues; however, its effects on osteoarthritic development remain unknown. Here, we demonstrated the function of 3′‐sialyllactose on osteoarthritic cartilage destruction. In vitro and ex vivo, biochemical and histological analysis demonstrated that 3′‐sialyllactose was sufficient to restore the synthesis of Col2a1 and accumulation of sulphated proteoglycan, a critical factor for cartilage regeneration in osteoarthritic development, and blocked the expression of Mmp3, Mmp13 and Cox2 induced by IL‐1β, IL‐6, IL‐17 and TNF‐α, which mediates cartilage degradation. Further, reporter gene assays revealed that the activity of Sox9 as a transcription factor for Col2a1 expression was accelerated by 3′‐sialyllactose, whereas the direct binding of NF‐κB to the Mmp3, Mmp13 and Cox2 promoters was reduced by 3′‐sialyllactose in IL‐1β‐treated chondrocytes. Additionally, IL‐1β induction of Erk phosphorylation and IκB degradation, representing a critical signal pathway for osteoarthritic development, was totally blocked by 3′‐sialyllactose in a dose‐dependent manner. In vivo, 3′‐sialyllactose protected against osteoarthritic cartilage destruction in an osteoarthritis mouse model induced by destabilization of the medial meniscus, as demonstrated by histopathological analysis. Our results strongly suggest that 3′‐sialyllactose may ameliorate osteoarthritic cartilage destruction by cartilage regeneration via promoting Col2a1 production and may inhibit cartilage degradation and inflammation by suppressing Mmp3, Mmp13 and Cox2 expression. The effects of 3′‐sialyllactose could be attributed in part to its regulation of Sox9 or NF‐κB and inhibition of Erk phosphorylation and IκB degradation. Taken together, these effects indicate that 3′‐sialyllactose merits consideration as a natural therapeutic agent for protecting against osteoarthritis.

Genome Engineering of Stem Cells for Autonomously Regulated, Closed-Loop Delivery of Biologic Drugs

Chronic inflammatory diseases such as arthritis are characterized by dysregulated responses to pro-inflammatory cytokines such as interleukin-1 (IL-1) and tumor necrosis factor α (TNF-α). Pharmacologic anti-cytokine therapies are often effective at diminishing this inflammatory response but have significant side effects and are used at high, constant doses that do not reflect the dynamic nature of disease activity. Using the CRISPR/Cas9 genome-engineering system, we created stem cells that antagonize IL-1- or TNF-α-mediated inflammation in an autoregulated, feedback-controlled manner. Our results show that genome engineering can be used successfully to rewire endogenous cell circuits to allow for prescribed input/output relationships between inflammatory mediators and their antagonists, providing a foundation for cell-based drug delivery or cell-based vaccines via a rapidly responsive, autoregulated system. The customization of intrinsic cellular signaling pathways in stem cells, as demonstrated here, opens innovative possibilities for safer and more effective therapeutic approaches for a wide variety of diseases.

Increased Chondrogenic Potential of Mesenchymal Cells From Adipose Tissue Versus Bone Marrow-Derived Cells in Osteoarthritic In Vitro Models

Primarily, to compare the behavior of human mesenchymal stem cells (MSCs) derived from bone marrow (hBMSCs) and adipose tissue (hADSCs) in an osteoarthritic (OA) microenvironment; secondly, to investigate the reaction of these cell types in two alternative in vitro culture systems, obtained by using TNFα and/or IL1β as inflammation mediators, or by using synovial fluid harvested by OA patients (OSF) to simulate the complex inflamed knee microenvironment. 3D micromass cultures of hBMSCs or hADSCs were grown in chondrogenic medium (CTR), in the presence of TNFα and/or IL1β, or synovial fluid from OA patients. After 1 month of culture, the chondrogenic differentiation of micromasses was evaluated by gene expression, matrix composition, and organization. Both hMSCs types formed mature micromasses in CTR, but a better response of hADSCs to the inflammatory environment was documented by micromass area and Bern score evaluations. The addition of OSF elicited a milder reaction than with TNFα and/or IL1β by both cell types, probably due to the presence of both catabolic and protective factors. In particular, SOX9 and ACAN gene expression and GAG synthesis were more abundant in hADSCs than hBMSCs when cultured in OSF. The expression of MMP1 was increased for both hMSCs in inflammatory conditions, but in particular by hBMSCs. hADSCs showed an increased chondrogenic potential in inflammatory culture systems, suggesting a better response of hADSCs in the OA environment, thus underlining the importance of appropriate in vitro models to study MSCs and potential advantages of using these cells for future clinical applications. J. Cell. Physiol. 232: 1478-1488, 2017. © 2016 Wiley Periodicals, Inc.

Optimization of a nonviral transfection system to evaluate Cox-2 controlled interleukin-4 expression for osteoarthritis gene therapy in vitro

BACKGROUND

Gene therapy appears to have the potential for achieving a long-term remedy for osteoarthritis (OA). However, there is a risk of adverse reactions, especially when using cytomegalovirus-controlled expression. To provide a safe application, we focused on the expression of therapeutic cytokines [e.g. interleukin (IL)-4] in a disease-responsive manner by use of the previously cloned Cox-2 promoter as 'genetic switch'. In the present study, we report the functionality of a controlled gene therapeutic system in an equine osteoarthritic cell model.

METHODS

Different nonviral transfection reagents were tested for their efficiency on equine chondrocytes stimulated with equine IL-1β or lipopolysaccharide to create an inflammatory environment. To optimize the transfection, we successfully redesigned the vector by excluding the internal ribosomal entry site (IRES). The functionality of our Cox-2 promoter construct with respect to expressing IL-4 was proven at the mRNA and protein levels and the anti-inflammatory potential of IL-4 was confirmed by analyzing the expression of IL-1β, IL-6, IL-8, matrix metalloproteinase (MMP)-1, MMP-3 and tumor necrosis factor (TNF)-α using a quantitative polymerase chain reaction.

RESULTS

Nonviral transfection reagents yielded transfection rates from 21% to 44% with control vectors with and without IRES, respectively. Stimulation of equine chondrocytes resulted in a 20-fold increase of mRNA expression of IL-1β. Such exogenous stimulation of chondrocytes transfected with pNCox2-IL4 led to an increase of IL-4 mRNA expression, whereas expression of inflammatory mediators decreased. The timely link between these events confirms the anti-inflammatory potential of synthesized IL-4.

CONCLUSIONS

We consider that this approach has significant potential for translation into a useful anti-inflammation therapy. Molecular tools such as the described therapeutic plasmid pave the way for a local-controlled, self-limiting gene therapy.

DNA Sequence Variants in the Five Prime Untranslated Region of the Cyclooxygenase-2 Gene Are Commonly Found in Healthy Dogs and Gray Wolves

The aim of this study was to investigate the frequency of regional DNA variants upstream to the translation initiation site of the canine Cyclooxygenase-2 (Cox-2) gene in healthy dogs. Cox-2 plays a role in various disease conditions such as acute and chronic inflammation, osteoarthritis and malignancy. A role for Cox-2 DNA variants in genetic predisposition to canine renal dysplasia has been proposed and dog breeders have been encouraged to select against these DNA variants. We sequenced 272–422 bases in 152 dogs unaffected by renal dysplasia and found 19 different haplotypes including 11 genetic variants which had not been described previously. We genotyped 7 gray wolves to ascertain the wildtype variant and found that the wolves we analyzed had predominantly the second most common DNA variant found in dogs. Our results demonstrate an elevated level of regional polymorphism that appears to be a feature of healthy domesticated dogs.

Gene therapy approaches to regenerating the musculoskeletal system

Injuries to the musculoskeletal system are common, debilitating and expensive. In many cases, healing is imperfect, which leads to chronic impairment. Gene transfer might improve repair and regeneration at sites of injury by enabling the local, sustained and potentially regulated expression of therapeutic gene products; such products include morphogens, growth factors and anti-inflammatory agents. Proteins produced endogenously as a result of gene transfer are nascent molecules that have undergone post-translational modification. In addition, gene transfer offers particular advantages for the delivery of products with an intracellular site of action, such as transcription factors and noncoding RNAs, and proteins that need to be inserted into a cell compartment, such as a membrane. Transgenes can be delivered by viral or nonviral vectors via in vivo or ex vivo protocols using progenitor or differentiated cells. The first gene transfer clinical trials for osteoarthritis and cartilage repair have already been completed. Various bone-healing protocols are at an advanced stage of development, including studies with large animals that could lead to human trials. Other applications in the repair and regeneration of skeletal muscle, intervertebral disc, meniscus, ligament and tendon are in preclinical development. In addition to scientific, medical and safety considerations, clinical translation is constrained by social, financial and logistical issues.

Evidence for regulated interleukin-4 expression in chondrocyte-scaffolds under in vitro inflammatory conditions

Objective

To elucidate the anti-inflammatory and anabolic effects of regulated expression of IL-4 in chondrocyte-scaffolds under in vitro inflammatory conditions.

Methods

Mature articular chondrocytes from dogs (n = 3) were conditioned through transient transfection using pcDNA3.1.cIL-4 (constitutive) or pCOX-2.cIL-4 (cytokine-responsive) plasmids. Conditioned cells were seeded in alginate microspheres and rat-tail collagen type I matrix (CaReS®) to generate two types of tissue-engineered 3-dimensional scaffolds. Inflammatory arthritis was simulated in the packed chondrocytes through exogenous addition of recombinant canine (rc) IL-1β (100 ng/ml) plus rcTNFα (50 ng/ml) in culture media for 96 hours. Harvested cells and culture media were analyzed by various assays to monitor the anti-inflammatory and regenerative (anabolic) properties of cIL-4.

Results

cIL-4 was expressed from COX-2 promoter exclusively on the addition of rcIL-1β and rcTNFα while its expression from CMV promoter was constitutive. The expressed cIL-4 downregulated the mRNA expression of IL-1β, TNFα, IL-6, iNOS and COX-2 in the cells and inhibited the production of NO and PGE₂ in culture media. At the same time, it up-regulated the expression of IGF-1, IL-1ra, COL2a1 and aggrecan in conditioned chondrocytes in both scaffolds along with a diminished release of total collagen and sGAG into the culture media. An increased amount of cIL-4 protein was detected both in chondrocyte cell lysate and in concentrated culture media. Neutralizing anti-cIL-4 antibody assay confirmed that the anti-inflammatory and regenerative effects seen are exclusively driven by cIL-4. There was a restricted expression of IL-4 under COX-2 promoter possibly due to negative feedback loop while it was over-expressed under CMV promoter (undesirable). Furthermore, the anti-inflammatory /anabolic outcomes from both scaffolds were reproducible and the therapeutic effects of cIL-4 were both scaffold- and promoter-independent.

Conclusions

Regulated expression of therapeutic candidate gene(s) coupled with suitable scaffold(s) could potentially serve as a useful tissue-engineering tool to devise future treatment strategies for osteoarthritis.

Mesenchymal stem cells and osteoarthritis: remedy or accomplice?

Multipotent mesenchymal stromal or stem cells (MSCs) are likely to be agents of connective tissue homeostasis and repair. Because the hallmark of osteoarthritis (OA) is degeneration and failure to repair connective tissues it is compelling to think that these cells have a role to play in OA. Indeed, MSCs have been implicated in the pathogenesis of OA and, in turn, progression of the disease has been shown to be therapeutically modulated by MSCs. This review discusses current knowledge on the potential of both marrow- and local joint-derived MSCs in OA, the mode of action of the cells, and possible effects of the osteoarthritic niche on the function of MSCs. The use of stem cells for repair of isolated cartilage lesions and strategies for modulation of OA using local cell delivery are discussed as well as therapeutic options for the future to recruit and appropriately activate endogenous progenitors and/or locally systemically administered MSCs in the early stages of the disease. The use of gene therapy protocols, particularly as they pertain to modulation of inflammation associated with the osteoarthritic niche, offer an additional option in the treatment of this chronic disease. In summary, elucidation of the etiology of OA and development of technologies to detect early disease, allied to an increased understanding of the role MSCs in aging and OA, should lead to more targeted and efficacious treatments for this debilitating chronic disease in the future.

Development of an inflammation-inducible gene expression system using helper-dependent adenoviral vectors

BACKGROUND

Clinical studies have shown that gene therapy is a promising approach for treating such genetic diseases as the eye disease, Leber's congenital amaurosis. Development of gene therapy approaches for treating chronic inflammatory diseases is, however, more challenging because it requires the production of anti-inflammatory molecules at the diseased tissues only when they are needed.

METHODS

We designed such a system by modifying the human interleukin (IL)-6 gene promoter to direct transgene expression and delivered the system into cultured cells as well as mouse lungs using a helper-dependent adenoviral vector.

RESULTS

We have demonstrated both in vitro and in vivo that the reporter LacZ or human IL-10 gene can be induced by inflammatory stimuli.

CONCLUSIONS

The results obtained indicate that the inflammation inducible gene expression system based on the modified human IL-6 gene promoter has the potential to be used for developing gene therapy for treating inflammatory diseases.

PTHrP overexpression partially inhibits a mechanical strain-induced arthritic phenotype in chondrocytes

OBJECTIVE

Cell-based tissue engineering strategies are currently in clinical use and continue to be developed at a rapid pace for the repair of cartilage defects. Regardless of the repair methodology, chondrocytes within newly regenerated cartilage remain susceptible to the abnormal inflammatory and mechanical environments that underlie osteoarthritic disease, likely compromising the implant's integration, function, and longevity. The present study investigates the use of parathyroid hormone-related peptide (PTHrP) overexpression for chondroprotection.

DESIGN

Bovine articular chondrocytes were transfected with human PTHrP (hPTHrP) constructs (1-141 or 1-173) and subjected to injurious cyclic tensile strain (CTS; 0.5 Hz and 16% elongation) for 48 h. mRNA expression of matrix remodeling, inflammatory signaling, hypertrophic, and apoptotic genes were examined with real-time reverse transcription polymerase chain reaction. Nitric oxide (NO) and prostaglandin E₂ (PGE₂) production were measured using the Griess assay and enzyme immunoassay (EIA), respectively.

RESULTS

CTS-induced an arthritic phenotype in articular chondrocytes as indicated by increased gene expression of collagenases and aggrecanases and increased production of NO and PGE₂. Additionally, CTS increased collagen type X (Col10a1) mRNA expression, whereas overexpression of either hPTHrP isoform inhibited CTS-induced Col10a1 gene expression. However, hPTHrP 1-141 augmented CTS-induced NO and PGE₂ production, and neither hPTHrP isoform had any significant effect on apoptotic genes.

CONCLUSIONS

Our results suggest that chondrocytes overexpressing PTHrP resist mechanical strain-induced hypertrophic-like changes. Therapeutic PTHrP gene transfer may be considered for chondroprotection applications in newly regenerated cartilage.

Gene therapy in autoimmune diseases: challenges and opportunities

Clinical treatment of autoimmune disorders presents a special challenge. For decades, most clinical regimens in autoimmunity has been largely symptomatic and non-disease specific. Although data from vigorous research has lead to accumulating knowledge on the pathogenic and immunological mechanisms of many autoimmune diseases, their direct clinical applications have been sparse. Advances in biotechnology have laid the groundwork for potent and specific molecular targeting therapies by gene therapy, and have just begun to be investigated in the treatment of autoimmune disorders. Such work has been largely based on the availability of well-established animal models of common autoimmune disorders, and the efficacy of strategic approaches initially investigated and validated in these models. Although these preclinical animal model studies have provided the proof-of-concept for multiple potential applications, human clinical trials on gene therapy in autoimmunity are still at its infancy. The recent success of Phase I/II clinical trials of gene therapy in rheumatoid arthritis and multiple sclerosis, development of cutting edge technology in target identification, as well as gene delivery systems have now set the stage for a more thorough and vigorous pace in the near future to advance this exciting field.