The establishment of a porcine rheumatoid arthritis model: Collagen induced arthritis minipig model

Advances in experimental models of rheumatoid arthritis

Rheumatoid arthritis (RA) is a chronic systemic autoimmune disease characterized by persistent articular inflammation and joint damage. RA was first described over 200 years ago; however, its etiology and pathophysiology remain insufficiently understood. The current treatment of RA is mainly empirical or based on the current understanding of etiology with limited efficacy and/or substantial side effects. Thus, the development of safer and more potent therapeutics, validated and optimized in experimental models, is urgently required. To improve the transition from bench to bedside, researchers must carefully select the appropriate experimental models as well as draw the right conclusions. Here, we summarize the establishment, pathological features, potential mechanisms, advantages, and limitations of the currently available RA models. The aim of the review is to help researchers better understand available RA models; discuss future trends in RA model development, which can help highlight new translational and human-based avenues in RA research.

Therapeutic effect of intra-articular injected 3'-sialyllactose on a minipig model of rheumatoid arthritis induced by collagen

Background

Rheumatoid arthritis (RA) is a chronic inflammatory disease of joint, but there is no known cure.

3′-sialyllactose (3′-SL) is an oligosaccharide that is abundant in breast milk of mammals, and has anti-inflammatory properties. However, the efficacy of 3′-SL on RA remains unclear. The objective of the present study was to evaluate the therapeutic effect of 3′-SL after it was directly injected into the knee joint cavity of a RA minipig model.

Results

Minipig RA model was induced by intra-articular injection of bovine type II collagen emulsified with complete or incomplete Freund’s adjuvant into left knee joint. In clinical assessment, lameness and swelling of the hindlimb and increased knee joint width were observed in all animals. After the onset of arthritis, 3′-SL (0, 2, 10, and 50 mg/kg) was directly administered to the left knee joint cavity once a week for 4 weeks. Compared to the vehicle control group, no significant difference in macroscopic observation of the synovial pathology or the expression of inflammation-related genes (IL-1β, TNF-α, and COX2) in the synovial membrane of the knee joint was found. In microscopic observation, cell cloning of the articular cartilage was significantly reduced in proportion to the concentration of 3′-SL administered.

Conclusions

Our results suggest that intra-articular injected 3′-SL had a therapeutic effect on collagen-induced arthritis at the cellular level with potential as a medication for RA.

Supplementary Information

The online version contains supplementary material available at 10.1186/s42826-022-00119-2.

Transplantation of IL‑1β siRNA‑modified bone marrow mesenchymal stem cells ameliorates type II collagen‑induced rheumatoid arthritis in rats

Rheumatoid arthritis (RA) is a chronic autoimmune disease that causes erosion of articular cartilage and bone and has adverse effects on both patients and livestock animals. The aim of the present study was to investigate the role of interleukin-1β (IL-1β) in the pathogenesis of RA, and to further determine whether injection of IL-1β small interfering RNA (siRNA) or transplantation of IL-1β siRNA + bone marrow mesenchymal stem cells (BMSCs) can ameliorate RA in rats. A collagen-induced arthritis (CIA) rat model was established by injecting type II collagen for 4 weeks. Next, CIA rats were randomly divided into three groups and injected or transplanted with PBS, IL-1β siRNA and IL-1β siRNA + BMSCs for another 4 weeks. The CIA rat model was successfully established, as demonstrated by the higher toe swelling value, thymus and spleen/body weight, immobility time and serum IL-1β concentration, as well as lower body weight, climbing time and mRNA expression of programmed death-1 (PD-1), transforming growth factor-β1 (TGF-β1) and forkhead box protein 3 (Foxp3) in the spleen, compared with control rats. Furthermore, histopathology results demonstrated that joint swelling and redness were observed in the knee joints of CIA rats. H&E results revealed that CIA rats presented erosive destruction of the bone and ulceration of the articular cartilage. In addition, in vitro results demonstrated that IL-1β expression was successfully silenced after IL-1β siRNA transfection in lipopolysaccharide-stimulated BMSCs. When compared with the results of PBS rats, both IL-1β siRNA injection and IL-1β siRNA + BMSC transplantation significantly increased the body weight, climbing time and mRNA expression of PD-1, TGF-β1 and Foxp3 in the spleen, while significantly reduced the immobility time and serum IL-1β concentration. In addition, when compared with that of IL-1β siRNA injection, IL-1β siRNA + BMSC transplantation exhibited markedly higher therapeutic efficacy against CIA. These results demonstrated that higher IL-1β contributed to the pathogenesis of CIA, and that IL-1β siRNA injection ameliorated CIA, while its combination with BMSCs exerted synergistic effects, which may be beneficial against RA.

The Peripherin Gene Regulates the Migration of Bone Marrow Mesenchymal Stem Cells in Wuzhishan Mini Pigs

Increasing the migratory capacity of the implanted mesenchymal stem cells (MSCs) is a major challenge in developing successful cell transplantation therapies. Nevertheless, the regulatory factors involved in the migration of BMMSCs remain largely unknown. In this study, we studied the role of the peripherin (PRPH) gene in regulating the ability of Wuzhishan mini pig (WZSP) BMMSCs to migrate in vitro. Four different shRNA vectors directed against PRPH were designed and transfected into BMMSCs. The vector with the best interference effect was chosen to be used in the following experiments. The expression level of PRPH in BMMSCs was determined by quantitative real-time PCR and western blot analysis. The migration capacity of the BMMSCs was estimated using a scratch assay, a transwell in vitro migration model assay, and filamentous actin staining. The results showed that shRNA-mediated knockdown of the expression of the PRPH gene in BMMSCs reduced the ability of these cells to migrate. Overall, these results illustrate that the PRPH gene regulates the migration of BMMSCs in the WZSP.

Peripheral mechanisms of arthritic pain: A proposal to leverage large animals for in vitro studies

Pain arising from musculoskeletal disorders such as arthritis is one of the leading causes of disability. Whereas the past 20-years has seen an increase in targeted therapies for rheumatoid arthritis (RA), other arthritis conditions, especially osteoarthritis, remain poorly treated. Although modulation of central pain pathways occurs in chronic arthritis, multiple lines of evidence indicate that peripherally driven pain is important in arthritic pain. To understand the peripheral mechanisms of arthritic pain, various in vitro and in vivo models have been developed, largely in rodents. Although rodent models provide numerous advantages for studying arthritis pathogenesis and treatment, the anatomy and biomechanics of rodent joints differ considerably to those of humans. By contrast, the anatomy and biomechanics of joints in larger animals, such as dogs, show greater similarity to human joints and thus studying them can provide novel insight for arthritis research. The purpose of this article is firstly to review models of arthritis and behavioral outcomes commonly used in large animals. Secondly, we review the existing in vitro models and assays used to study arthritic pain, primarily in rodents, and discuss the potential for adopting these strategies, as well as likely limitations, in large animals. We believe that exploring peripheral mechanisms of arthritic pain in vitro in large animals has the potential to reduce the veterinary burden of arthritis in commonly afflicted species like dogs, as well as to improve translatability of pain research into the clinic.

Splenic artery denervation: target micro-anatomy, feasibility, and early preclinical experience

This study sought to evaluate perisplenic artery nerve distribution and the feasibility of splenic artery denervation (SDN). The NEXION radiofrequency catheter was used to perform SDN in healthy and inflammatory arthritis pigs. Splenic artery anatomy, nerve distribution, and splenic norepinephrine (NEPI) levels were evaluated before and after SDN. Perisplenic artery nerves were primarily distributed within 2.5 mm of the arterial lumen and were largely sympathetic on the basis of tyrosine hydroxylase expression. The pancreas, tended to be circumferentially positioned around the proximal splenic artery, typically >2.5 mm from the lumen, ensuring that most of the nerves could be targeted without affecting this sensitive organ. The mid segment of the splenic artery was relatively free of contact with the adjacent pancreas. Splenic NEPI levels and nerve abundance followed a decreasing gradient from the proximal to distal splenic artery. SDN resulted in significant reductions in splenic NEPI levels at day 14 (60.7%, P = 0.024) in naïve pigs and day 45 (100%, P = 0.001) in inflammatory arthritis pigs. There was no significant effect of SDN on joint soft tissue injury or circulating inflammatory markers in the inflammatory arthritis model. The majority of perisplenic arterial nerves are within close proximity of the lumen and are primarily sympathetic efferent fibers. Nerves in the mid-segment may be the preferred SDN target given their proximity to the artery and paucity of periarterial off-target organs. SDN appears safe and effective at reducing splenic NEPI levels.

Subpopulations of miniature pig mesenchymal stromal cells with different differentiation potentials differ in the expression of octamer-binding transcription factor 4 and sex determining region Y-box 2

Objective

Human mesenchymal stromal cells (MSCs) exhibit variable differentiation potential and can be divided accordingly into distinct subpopulations whose ratios vary with donor age. However, it is unknown whether the same is true in pigs. This study investigated MSC subpopulations in miniature pig and compared their characteristics in young (2 to 3 months) and adult (27 to 35 months) pigs.

Methods

Osteogenic, chondrogenic, and adipogenic capacity of isolated MSCs was evaluated by von Kossa, Alcian blue, and oil red O staining, respectively. Cell surface antigen expression was determined by flow cytometry. Proliferative capacity was assessed with the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. Expression of marker genes was detected by quantitative real-time polymerase chain reaction.

Results

Porcine MSCs comprised cells with trilineage and bilineage differentiation potential (tMSCs and bMSCs, respectively) and non-differentiating stromal cells (NDSCs). The tMSC and bMSC fractions were smaller in adult than in young pigs (63.0% vs 71.2% and 11.6% vs 24.0%, respectively, p<0.05); NDSCs showed the opposite trend (25.4% vs 4.8%; p<0.05). Subpopulations showed no differences in morphology, cell surface antigen expression, or proliferative capacity, but octamer-binding transcription factor 4 (OCT4) expression was higher in tMSCs than in bMSCs and NDSCs (p<0.05), whereas sex determining region Y-box 2 (SOX2) expression was higher in tMSCs and bMSCs than in NDSCs (p<0.05). Aging had no effect on these trends.

Conclusion

Porcine MSCs comprise distinct subpopulations that differ in their differentiation potential and OCT4 and SOX2 expression. Aging does not affect the characteristics of each subpopulation but alters their ratios.

Cardiac phenotype in mouse models of systemic autoimmunity

Patients suffering from systemic autoimmune diseases are at significant risk of cardiovascular complications. This can be due to systemically increased levels of inflammation leading to accelerated atherosclerosis, or due to direct damage to the tissues and cells of the heart. Cardiac complications include an increased risk of myocardial infarction, myocarditis and dilated cardiomyopathy, valve disease, endothelial dysfunction, excessive fibrosis, and bona fide autoimmune-mediated tissue damage by autoantibodies or auto-reactive cells. There is, however, still a considerable need to better understand how to diagnose and treat cardiac complications in autoimmune patients. A range of inducible and spontaneous mouse models of systemic autoimmune diseases is available for mechanistic and therapeutic studies. For this Review, we systematically collated information on the cardiac phenotype in the most common inducible, spontaneous and engineered mouse models of systemic lupus erythematosus, rheumatoid arthritis and systemic sclerosis. We also highlight selected lesser-known models of interest to provide researchers with a decision framework to choose the most suitable model for their study of heart involvement in systemic autoimmunity.