The Effect of Inhaled Air Particulate Matter SRM 1648a on the Development of Mild Collagen-Induced Arthritis in DBA/J Mice

Air pollution is considered to be one of a risk factor for rheumatoid arthritis (RA). Collagen-induced arthritis (CIA) is commonly used as a mouse model of human RA. However, the impact of specific particulate matter (PM) components on the incidence and severity of RA has still not been established. The aim of this study was to develop an experimental model of CIA suitable to test arthritogenicity of inhaled PM. A mild form of CIA was induced in DBA1/J mice inhaled with various components of SRM 1648a PM. The incidence and severity of arthritis was assessed, and the selected serum markers of autoimmunity and inflammation were determined. Clinical arthritis was observed from the booster CII immunisation onward. Anti-cyclic citrullinated peptide antibodies, a diagnostic marker of RA, were detected in serum of these mice. All inhaled pollutants, crude PM, PM with reduced organic content, ferric, and silica nanoparticles markedly increased CIA incidence and severity. The fastest progression of CIA development was caused by crude PM and was linked to enhanced serum levels of anti-CII IgG, the prominent arthritogenic autoantibodies. On the other hand, inhaled nanoparticles enhanced serum levels of TNFα, a major proinflammatory arthritogenic cytokine. We recommend this experimental model of mild CIA to test the mechanisms of arthritis exacerbation by inhaled air pollutants. Further studies are necessary to determine whether PM-aggravated arthritis is caused by inflammatory mediators translocated from inflamed lung into systemic circulation or whether PM translocated into the bloodstream directly exacerbate joint inflammation.

Microstructure and mechanical behaviors of tibia for collagen-induced arthritic mice treated with gingiva-derived mesenchymal stem cells

Rheumatoid arthritis (RA) is a systemic polyarticular arthritis that primarily affects the small joints but also causes bone erosion in large joints. None of the currently existing treatment approaches is curable. In this study, the effects of human gingiva-derived mesenchymal stem cells (GMSCs) on collagen-induced arthritis (CIA) mice are examined by experimentally assessing the microstructure and mechanical behaviors of tibia. Bone morphology and mineral density of mouse tibiae were assessed using micro-X-ray computed tomography (micro-CT). Compression testing was performed on mouse tibia to access its stiffness. The deformation and strain localized inside proximal tibia were mapped using mechanical testing coupled with micro-CT and digital volume correlation of micro-CT images. The results show that CIA disease caused bone erosion in epiphyseal cortical bone, which manifested into the adjacent epiphyseal trabecular bone, and also affected the metaphyseal cortical bone. CIA disease also weakened the load-bearing function of proximal tibia. GMSC treatment interfered with the progress of CIA, attenuated the bone erosion in epiphyseal and metaphyseal trabecular bone and resulted in improved load-bearing function of proximal tibia. GMSCs provide a promising potential treatment of autoimmune arthritis.

The impact of airborne endotoxin exposure on rheumatoid arthritis-related joint damage, autoantigen expression, autoimmunity, and lung disease

Airborne biohazards are risk factors in the development and severity of rheumatoid arthritis (RA) and RA-associated lung disease, yet the mechanisms explaining this relationship remain unclear. Lipopolysaccharide (LPS, endotoxin) is a ubiquitous inflammatory agent in numerous environmental and occupational air pollutant settings recognized to induce airway inflammation. Combining repetitive LPS inhalation exposures with the collagen induced arthritis (CIA) model, DBA1/J mice were assigned to either: sham (saline injection/saline inhalation), CIA (CIA/saline), LPS (saline/LPS 100 ng inhalation), or CIA + LPS for 5 weeks. Serum anti-citrullinated (CIT) protein antibody (ACPA) and anti-malondialdehyde-acetaldehyde (MAA) antibodies were strikingly potentiated with co-exposure (CIA + LPS). CIT- and MAA-modified lung proteins were increased with co-exposure and co-localized across treatment groups. Inhaled LPS exacerbated arthritis with CIA + LPS > LPS > CIA versus sham. Periarticular bone loss was demonstrated in CIA and CIA + LPS but not in LPS alone. LPS induced airway inflammation and neutrophil infiltrates were reduced with co-exposure (CIA + LPS). Potentially signaling transition to pro-fibrotic processes, there were increased infiltrates of activated CD11c+CD11b+ macrophages and transitioning CD11c+CD11bint monocyte-macrophage populations with CIA + LPS. Moreover, several lung remodeling proteins including fibronectin and matrix metalloproteinases as well as complement C5a were potentiated with CIA + LPS compared to other treatment groups. IL-33 concentrations in lung homogenates were enhanced with CIA + LPS with IL-33 lung staining driven by LPS. IL-33 expression was also significantly increased in lung tissues from patients with RA-associated lung disease (N = 8) versus controls (N = 7). These findings suggest that patients with RA may be more susceptible to developing interstitial lung disease following airborne biohazard exposures enriched in LPS.

Expression of mBD4, mBD3 and CRAMP during type II collagen-induced arthritis/CIA and their association with inflammation and bone-remodeling markers

The aim of this study was to analyze the expression of mBD4, mBD3 and CRAMP in joint of mice with type II collagen-induced arthritis/CIA and to explore its possible association with IL-10, IL-4, IFN-γ, IL-17, MMP3, RANK/RANKL/OPG and histological parameters.

METHODS

CIA was induced in 44 DBA/1 J mice. The joints from mice were classified into the onset, peak and remission phase of CIA. Histological sections were stained with hematoxylin-eosin and safranin O. The expression of CRAMP, mBD-3, mBD-4, and MMP-3 was evaluated using reverse transcription polymerase chain reaction (RT-PCR) and immunohistochemistry. The expression of IL-10, IL-4, IFN-γ, IL-17, RANK/RANKL/OPG was analyzed by RT-PCR.

RESULTS

We observed that inflammation and immunostained cells for CRAMP increased in the peak and remission phases compared to the control group. In addition, increments in relative expressions of CRAMP were detected for the remission phase and in IL-4 and IL-17 in the peak phase compared to the control and onset phase. In addition, an increase in IL-10 in a peak phase compared to the control, as well as the relative expression of IFN-γ in remission phase was higher than in the onset phase. This was accompanied by an increase in cartilage damage in the peak phase compared to the control. Cells immunostained to MMP3 increased in the peak phase compared to the onset and control group, and relative expression of MMP3 was detected in the peak phase compared to the onset, remission, and control group. We observed that the relative expression of RANK and RANKL in the peak phase was higher than in control and onset phase. Finally, the relative expression of OPG in the peak phase compared to the onset, remission, and control group was detected. Regarding CRAMP behavior in the different phases studied, it was positively correlated with IL-4 and RANK, and showed a negative correlation with IFN-γ, IL-17, IL-10, RANKL, OPG and RANKL/OPG ratio in the control group. Also was positively correlated with IFN-γ, IL-17, IL-4, IL-10, as well as with RANK, RANKL, and OPG in the onset and peak phases of the CIA. In the peak phase, CRAMP showed a positive association with MMP3, and we observed a direct correlation between CRAMP and IFN-γ and RANKL/OPG ratio in remission phase. mBD3 correlates positively with IFN-γ, IL-17, IL-10, RANKL, OPG and RANKL/OPG ratio, and showed a negative correlation with CRAMP, MMP3, and RANK in the control group. Also, it was directly associated with IFN-γ, IL-17, IL-4, IL-10 and RANKL in the onset phase while it was inversely associated with CRAMP, MMP-3, RANK, RANKL, and OPG in the peak phase. Finally, mBD3 was inversely correlated with MMP3 in the remission phase and was directly associated with CRAMP, IFN-γ and RANKL/OPG ratio in this phase. mBD4 was directly associated with CRAMP, IFN-γ, IL-17, IL-4, IL-10, RANKL / OPG in the onset phase, and with CRAMP, IFN-γ, IL-17, IL-4, IL-10, MMP3, RANK, RANKL and OPG in the peak phase. Finally, mBD4 was positively associated with mBD3, IFN-γ, IL-17, IL-10, RANK, RANKL OPG and RANKL/OPG in the CIA remission phase.

CONCLUSIONS

Our results demonstrate that CRAMP plays an important role in CIA progress and suggest that its abundance is associated with local pro- and anti-inflammatory status. This makes us propose CRAMP as a possible contributor of bone reconstruction in the last stage of CIA.

Generation of a robust model for inducing autoimmune arthritis in Sprague Dawley rats

INTRODUCTION

The prerequisite for any experimental model in animals is similarity with the human disease, uniformity in disease severity and incidence. In antigen-induced arthritis models it is generally recognized that the major limitation is inconsistency in terms of incidence and severity. As access to strains like DBA/1 mice or Lewis rats is difficult for resource restrained laboratories, this study aimed to establish a robust and reproducible animal model of rheumatoid arthritis (RA).

METHODS

Multiple approaches were undertaken for inducing arthritis in Sprague Dawley (SD) and Wistar rats using complete Freund's adjuvant (CFA), collagen type II (CII) emulsion, or different combinations of CII with low dose CFA along with lipopolysaccharide (LPS). The development of arthritis was evaluated by measuring paw edema, arthritis score, body weight, splenic index, histopathology and radiography of paw tissues.

RESULTS

The combination of CII with low dose CFA and one injection of LPS resulted in 100% incidence of arthritis with disease severity ranging from moderate to severe and results were corroborated by histopathology and radiography.

DISCUSSION

In a head-to-head comparison between SD and Wistar rats, the disease profile was better sustained and consistent in SD rats, and the use of CII with low dose CFA and LPS induced features akin to human RA. Taken together, a reproducible model of arthritis was established which can be replicated in any laboratory with limited resources.

Data on arsenic trioxide modulates Treg/Th17/Th1/Th2 cells in treatment-naïve rheumatoid arthritis patients and collagen-induced arthritis model mice

In this article, we share the raw protein and mRNA data obtained from basal and stimulated human peripheral blood mononuclear cells (PBMCs) derived from 15 individual treatment-naïve rheumatoid arthritis (RA) patients and synovial fluid mononuclear cells (SFMCs). In treatment-naïve RA patients, PBMCs were treated with a gradient of concentrations of As₂O₃ (0, 0.1, 0.5, 1.0, 2.0, 4.0 μM) for 48 hours. We found that 2.0 μM As₂O₃ promoted the apoptosis of PBMCs significantly, and 0.5 μM As₂O₃ was the lowest and effective concentration that contributed to Treg cell generation but it prevented Th17 cell differentiation, as assessed by flow cytometry. Furthermore, As₂O₃ decreased the transcription factor STAT3 mRNA expression of Th17 cells but increased the transcription factor Foxp3 of Treg cells. In synovial fluid from RA patients, consistent with PBMCs, As₂O₃ inhibited Th17 cell differentiation but promoted Treg cell generation. In an animal experiment, we analyzed the body-weight of mice as the indicator of As₂O₃ toxicity and calculated the spleen index. As₂O₃ significantly decreased the hematoxylin and eosin score in Type II collagen-induced arthritis in mice. Furthermore, As₂O₃ downregulated the frequency of Th1 but upregulated Th2 cells. For more insight please see Arsenic trioxide improves Treg and Th17 balance by modulating STAT3 in treatment-naive rheumatoid arthritis patients [1].

Lactobacillus fermentum PC1 has the Capacity to Attenuate Joint Inflammation in Collagen-Induced Arthritis in DBA/1 Mice

Lactobacillus strains have shown efficacy in attenuating inflammation. This study evaluated the potential of Lactobacillus fermentum PC1 for the treatment of rheumatoid arthritis (RA) using a murine model of collagen-induced arthritis. On Day 1, healthy DBA/1 mice (six to eight weeks of age) were immunized, with 100 μg of Chicken Type 11 collagen emulsified in complete Freund’s adjuvant (CFA) by intradermal injection, at the base of the tail. On Day 21, the mice were immunized intraperitoneally with 100 μg of Bovine Type11 collagen in phosphate buffered saline (PBS). On Day 28, the mice were immunized intraperitoneally with 50 μg of lipopolysaccharide (LPS). Viable L. fermentum PC1 (1 × 10⁹ colony forming units) was given daily from Day two until the end of the experiment. From Day 21 onwards, the mice were monitored daily for clinical signs of arthritis. On Day 44, the experiment was terminated. Paws were obtained for histology and serum for cytokine assays. L. fermentum PC1-fed mice had significantly reduced paw inflammation as well as decreased synovial infiltration and less cartilage damage. Circulating serum cytokine profiles revealed decreased IL-12 and increased anti-inflammatory cytokines, namely IL-4 and IL-10. Thus, early administration of L.fermentum PC1 could prove to be a valuable therapeutic agent in the management of RA.

In vivo, Extract from Withania somnifera Root Ameliorates Arthritis via Regulation of Key Immune Mediators of Inflammation in Experimental Model of Arthritis

BACKGROUND

Rheumatoid Arthritis (RA) is a devastating disease characterized by continual addition of leukocytes and T cells within the articular cavity causing inflammation and cartilage destruction. Withania somnifera is one of the most precious medicinal herbs, reported to have antioxidant, anti-inflammatory, and immunomodulatory properties.

OBJECTIVE

The purpose of this study was to evaluate anti-inflammatory activity of aqueous extract of Withania somnifera roots (WSAq) in Collagen Induced Arthritic (CIA) rats.

METHODS

To achieve this, we assessed the level of inflammatory cytokines such as Tumor Necrosis Factor (TNF)-α, IL-1β, IL-6 and IL-10 in CIA rats. Further, transcription factor, oxidative stress parameters and CD+8 expressions were also analyzed in CIA rats.

RESULTS

Arthritic rats showed a greater increase in the levels of pro inflammatory cytokines such as TNF-α, IL-1β, IL-6, transcription factor NF-κB and a decrease in IL-10 concentration than controls rats. Oral administration of WSAq at a dose of 300mg/kg.wt. (WSAq300) appreciably attenuated the production of these pro inflammatory cytokines. This anti-inflammatory activity of WSAq300 might be partly mediated through an increase in the secretion of IL-10 and inhibition of NF-κB activity. Further, arthritic rats also show increased oxidative stress as compared to control rats. This increased oxidative stress in the arthritic rats appears to be the outcome of both an activated pro-oxidant and a poor antioxidant defense system. Treatment with WSAq300 strongly ameliorates all these ROS parameters significantly to near normal. Additional, metalloproteinase MMP-8 levels were also measured and found to be increased in CIA rats, which after treatment with WSAq300 came down to near normal.

CONCLUSION

From the above results, it can be concluded that the use of WSAq300 may be a valuable supplement which can improve human arthritis.

Efficacy of constant long-term delivery of YM-58483 for the treatment of rheumatoid arthritis

The aim of this study was to investigate the efficacy and safety of YM-58483, a small molecular antagonist of Ca²⁺ release-activated Ca²⁺ (CRAC) channels, for the treatment of rheumatoid arthritis (RA), in vivo and ex vivo. YM-58483 was continuously injected subcutaneously in a collagen-induced arthritis (CIA) mouS.E.M.odel using an implanted osmotic pump. The severity of CIA was evaluated using the following parameters: body weight, hind paw volume, clinical score, histological analysis, cytokine levels, Ca²⁺ influx, and specific IgG production. The efficacy of long-term application of YM-58483 was also verified ex vivo in RA patient-derived peripheral blood monocytes. Assessment of the clinical severity of CIA, cytokine profile in serum and joint protein extracts, and specific IgG production showed that continuous application of YM-58483 suppressed synovial inflammation by inhibiting immune cell activity. Chemical screening and hepatography indicated that long-term subcutaneous delivery of YM-58483 was safer than oral administration for systemic application. Moreover, constant preincubation with YM-58483 at an IC₅₀ of 0.1-1 nM altered proinflammatory cytokine production ex vivo in peripheral T cells derived from RA patients. Our findings suggest that continuous long-term application of appropriate CRAC inhibitors such as YM-58483 is a potential therapeutic strategy for global immunosuppression in RA.

Effect of 1,25-(OH)2D3 on Proliferation of Fibroblast-Like Synoviocytes and Expressions of Pro-Inflammatory Cytokines through Regulating MicroRNA-22 in a Rat Model of Rheumatoid Arthritis

OBJECTIVE

This study aims to investigate the regulatory mechanism of 1,25-(OH)2D3 on the proliferation of fibroblast-like synoviocytes (FLS) and expressions of pro-inflammatory cytokines in rheumatoid arthritis (RA) rats via microRNA-22 (miR-22).

METHODS

A rat model of RA was established with a subcutaneous injection of type II collagen. After treated with different concentrations of 1,25-(OH)2D3 the proliferation of FLS was estimated by the MTT method, and the optimal concentration of 1,25-(OH)2D3 was selected for further experiments. Cell proliferation was detected by MTT. Cell cycle and apoptosis were analyzed by FCM. The IL-1β, IL-6, IL-8, and PGE2 protein expressions were determined by ELISA, and MMP-3, INOS, and Cox-2 mRNA expressions were measured by qRT-PCR.

RESULTS

The rat model of RA was successfully established. Compared with the blank group, the 1,25-(OH)2D3 and miR-22 inhibitors groups exhibited higher proliferation inhibition and apoptosis rates, lower levels of pro-inflammatory cytokines (IL-1β, IL-6, IL-8, and PGE2), and decreased mRNA expressions of MMP-3, INOS, and Cox-2. The miR-22 mimics group had lower proliferation inhibition and apoptosis rates, elevated expressions of pro-inflammatory cytokines and MMP-3, INOS, and Cox-2 than the blank group. In contrast to the 1,25-(OH)2D3 group, the proliferation inhibition and apoptosis rates were down-regulated, and the expressions of pro-inflammatory cytokines and MMP-3, INOS, and Cox-2 were up-regulated in the 1,25-(OH)2D3 + miR-22 mimics group.

CONCLUSION

Our study demonstrated that 1,25-(OH)2D3 inhibits the proliferation of FLS and alleviates inflammatory response in RA rats by down-regulating miR-22.

Experimental Arthritis Mouse Models Driven by Adaptive and/or Innate Inflammation

Rheumatoid arthritis (RA) is a chronic systemic autoimmune disease mainly affecting synovial joints. The clinical presentation of RA shows the heterogeneity of this disease with its underlying complex interactions between the innate and adaptive immune system and flare-ups of disease. Different disease models such as collagen induced arthritis, antigen induced arthritis, and Streptococcal cell wall induced arthritis can be exploited to investigate different aspects of the pathogenesis of arthritis. The disease can be monitored macroscopically over time via scoring systems. For histological examination, paraffin embedded knee sections can be used for hematoxylin and eosin staining to visualize cellular infiltration as well as for tartrate-resistant acid phosphatase (TRAP) staining to identify osteoclast-like cells. Cellular infiltration of the synovium by different myeloid cells such as tissue resident macrophages, dendritic cells and neutrophils can be monitored using flow cytometry. Here, we describe the methods for inducing the different mouse models for arthritis, including scoring systems per model, histological and flow cytometric analysis.

In vivo anti-arthritic efficacy of Camellia sinensis (L.) in collagen induced arthritis model

BACKGROUND

Rheumatoid arthritis (RA), an autoimmune inflammatory disorder with synovial hyperplasia, destruction of cartilage, bone damage is often associated with risk of infections. Such risk could be attributed towards usage of immunosuppressive agents. Thus, the present study was undertaken to evaluate the anti-arthritic efficacy of aquo-alcoholic extract of Camellia sinensis (L.).

MATERIAL AND METHODS

Dried leaves of Camellia sinensis (L.) or Cs were filtered and extracted in 1:1 aqueous: ethanol by Soxhlet apparatus followed by lyophilization and spray drying to develop amorphous powder. Four different oral doses (50, 100, 200, 400mg/kg/body wt.) of aquo-alcoholic extract were evaluated for anti-edematogenic effect in collagen induced arthritis model. The selected anti-arthritic doses of Cs were evaluated for the oxidative stress markers like Glutathione [5-5'dithio-bis-2-nitrobenzoicacid (DTNB)], Superoxide dismutase [Epinephrine], Catalase [Hydrogen peroxide], Lipid peroxidation [Thiobarbituric acid reactive substance (TBARS)], Nitric oxide [Griess reagents:Nitrobluetetrazolium], Articular elastase [N-methoxysuccinyl-Ala-Ala-Pro- Val p-nitroanilide] in joints followed by haematological evaluation including RBC, WBC, Haemoglobin, platelets and haematocrit. To validate these biochemical changes, the radiological and histopathological (Haematoxylin & Eosin) evaluation was also conducted.

RESULTS

The selected anti-arthritic dose of Cs i.e. 400mg/kg/body wt. (∼60% anti-arthritic efficacy on 35th day) could be attributed towards significant (p<0.05) increase in the levels of enzymatic (Superoxide dismutase and Catalase) and non-enzymatic (Glutathione) antioxidants by 34%, 59% and 50% respectively. Simultaneously, the significant (p<0.05) reduction of lipid peroxides, nitrite radical and elastase activity by 32%, 45% & 32% respectively as compare to control indicated overall decrease in oxidative stress. Haematological evaluation revealed restoration of RBC, WBC and platelets level in treatment group. The confirmatory analysis utilizing radiological and histological assessment showed alleviation of joint deformity, tissue swelling, pannus formation and neutrophils infiltration in treatment group as compared to collagen induced arthritis.

CONCLUSION

The analysis showed that Cs can play an effective role in reduction of oxidative stress by modulating levels of antioxidants, reducing levels of free radicals while restoring normal haematopoietic cascade as observed in collagen induced arthritis model. Thus, the cumulative dose impact of 400mg/kg body wt., over a period of 14days also found extremely effective in terms of safeguarding their structural conformity against such auto-immune disorder.

Protective effects of a blueberry extract in acute inflammation and collagen-induced arthritis in the rat

Here we investigated the anti-inflammatory effect of a blueberry extract in the carrageenan-induced paw edema model and collagen-induced arthritis model, both in rats. Along with the chemical characterization of the phenolic content of the fruits and extract, the antioxidant potential of the extract, the cellular antioxidant activity and the effects over neutrophils' oxidative burst, were studied in order to provide a mechanistic insight for the anti-inflammatory effects observed. The extract significantly inhibited paw edema formation in an acute model the rat. Our results also demonstrate that the standardized extract had pharmacological activity when administered orally in the collagen-induced arthritis model in the rat and was able to significantly reduce the development of clinical signs of arthritis and the degree of bone resorption, soft tissue swelling and osteophyte formation, consequently improving articular function in treated animals.

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

Rheumatoid arthritis (RA) research has been largely dependent on collagen induced arthritis (CIA) rodent models, however, they may not translate well to humans due to innate differences in the size, physiology and lifespan. The present study aimed to establish a CIA porcine model with the physical, hematological, histopathological and etiological properties closer to their human equivalent in an attempt to better meet the needs of RA research. Three month old minipigs were administered of bovine type II collagen (CII) emulsified with complete Freund's adjuvants on Day 1 and incomplete Freund's adjuvants on Day 22, via an intradermal or intra-articular route. The clinical, radiological and hematological assessments of immunized animals were made periodically until Day 43, during which period the onset and progression of arthritis was recorded and characterized. In addition, the histopathological and micro-tomographic assessments of the cartilage degradation with regard to mononuclear cell infiltration, and joint deformity indicated a higher severity in the intradermal injection group over the intra-articular group. With confirmation of the susceptibility to heterogeneous CII for arthritis induction in minipig, the potential suitability of this test system as a large animal model for RA has been demonstrated.

Glabretal-type triterpenoid from the root bark of Dictamnus dasycarpus ameliorates collagen-induced arthritis by inhibiting Erk-dependent lymphocyte proliferation

ETHNOPHARMACOLOGICAL RELEVANCE

The root bark of Dictamnus dasycarpus Turcz. (Rutaceae) has been used as a traditional herbal medicine to treat various inflammatory diseases in East Asia. We have showed previously that a glabretal type triterpenoid (dictabretol A) from D. dasycarpus root bark has immunosuppressive activity.

AIM OF THE STUDY

This study was conducted to define the molecular mechanism of how dictabretol A inhibits lymphocyte proliferation and to evaluate the therapeutic efficacy of dictabretol A in an animal model of rheumatoid arthritis.

MATERIALS AND METHODS

Various murine immune cells (T cells, B cells, and macrophages) and splenocytes were used to study the anti-proliferative effect of dictabretol A in vitro. A collagen-induced arthritis model was also used to examine the therapeutic effect of dictabretol A in vivo.

RESULTS

Dictabretol A specifically inhibited lymphocyte proliferation by blocking the cell cycle transition from the G1 to the S phase. This effect was achieved by blocking Erk1/2, nuclear factor kappa B, and the C-myc axis of cell cycle progression. Further dictabretol A treatment alleviated the severity of collagen-induced arthritis.

CONCLUSION

Our results reveal the molecular mechanism for the anti-lymphoproliferative effect of dictabretol A and show the therapeutic efficacy of dictabretol A for rheumatoid arthritis.

A novel coumarin derivative, 8-methoxy chromen-2-one alleviates collagen induced arthritis by down regulating nitric oxide, NFκB and proinflammatory cytokines

Ruta graveolens (Rue) is a well-known medicinal plant having anti-inflammatory and other healing properties. This contains many active phytochemicals such as coumarins which possess anti-inflammatory and anti-cancer activities. The present study was carried out to evaluate the therapeutic potential of a newly isolated coumarin derivative from rue plant, 8-methoxy-chromen-2-one (MCO) in the collagen induced arthritic (CIA) rat model. MCO showed inhibition of cytokines and NF-κB in LPS stimulated J774 cells which prompted its possible use in animal. In CIA, arthritic index and arthritic score reduced markedly within 15days of MCO treatment at doses of 2mg and 20mg per kg body weight. Alleviation of joint damage in CIA animals on treatment with MCO was evident from radiographic and histological data. Behavioral studies by open field tests also showed convalescence in the MCO treated CIA rats. Further, escalated plasma levels of pro-inflammatory cytokines TNF-α, IL-1β and IL-6, and also nitric oxide reduced significantly with the treatment. All these results indicate the therapeutic efficacy of MCO and its possible use as an anti-arthritic drug.

Bi-specific antibodies with high antigen-binding affinity identified by flow cytometry

Using conventional approaches, the antigen-binding affinity of a novel format of bi-specific antibody (BsAb) cannot be determined until purified BsAb is obtained. Here, we show that new lipoprotein A (NlpA)-based bacteria display technology, combined with flow cytometry (FCM), can be used to detect antigen-binding affinity of BsAbs, in the absence of expression and purification work. Two formats of BsAb, scFv2-CH/CL and Diabody-CH/CL, specific for human interleukin 1β (hIL-1β) and human interleukin 17A (hIL-17A), were constructed and displayed in Escherichia coli using NlpA-based bacteria display technology. Conversion of these cells to spheroplasts, and their incubation with fluorescently conjugated antigens resulted in the selective labeling of spheroplasts expressing BsAb; enabling their antigen-binding affinity to be analyzed with FCM. The association and dissociation of BsAbs for binding to hIL-1β and hIL-17A were analyzed using FCM-based assays. The results showed that antigen-binding affinity of Diabody-CH/CL was significantly higher than that of scFv2-CH/CL. To confirm these results of FCM-based assays, BsAbs were expressed, purified and subjected to relative affinity measurements, in vitro and in vivo bioactivity analysis. The results showed that Diabody-CH/CL had greater relative affinities for both antigens, resulting in better blocking bioactivities on cellular level and effects on alleviating joint inflammation, and cartilage destruction and bone damage in collagen induced arthritis (CIA) mice model. These results indicate that BsAbs with good antigen-binding affinity can be identified by FCM-based assays without expression and purification work, and the indentified BsAb can serve as a lead compound for further drug development.

In vivo expression of recombinant pregnancy-specific glycoprotein 1a inhibits the symptoms of collagen-induced arthritis

PROBLEM

The contribution of Pregnancy-specific glycoproteins (PSG), the major variant of PSG released into the circulation during pregnancy, to the pregnancy-dependent improvement of rheumatoid arthritis (RA) has still not been elucidated.

METHOD OF STUDY

Collagen-induced arthritis (CIA) was used to test the hypothesis that PSG1a when released into circulation has a modulatory role on the Th1-pathogenic response, thus improving the CIA symptoms. In vivo expression of PSG1a was induced by injection of the vaccinia (Vac)-based expression vector harboring the complete open-reading frame of PSG1a cDNA.

RESULTS

In vivo PSG1a expression during the induction of CIA ameliorated the clinical symptoms, thereby reducing the arthritis score and incidence. Significantly lower levels of IL-17, IL-6, and IFN-γ, but higher levels of TGF-β and IL-10 were secreted by collagen type II-stimulated spleen mononuclear cells from Vac-PSG1a-treated mice compared with control mice. Moreover, Vac-PSG1a treatment promoted the increase in splenic CD4+CD25+Foxp3+ Treg cells.

CONCLUSION

Pre-clinical Vac-PSG1a treatment suppressed the Th1- and Th17-type-specific responses, leading to an increase in splenic Treg cells as well as IL-10- and TGF-β-secreting cells, with the CIA symptoms being ameliorated.

Boswellia serrata extract attenuates inflammatory mediators and oxidative stress in collagen induced arthritis

Rheumatoid arthritis (RA) is a chronic inflammatory disease which leads to destruction of joints. Current treatment modalities for RA either produce symptomatic relief (NSAIDs) or modify the disease process (DMARDs). Though effective, their use is also limited by their side effects. As a result, the interest in alternative, well tolerated anti-inflammatory remedies has re-emerged. Our aim was to evaluate the antioxidant and antiarthritic activity of Boswellia serrata gum resin extract (BSE) in collagen induced arthritis. Arthritis was induced in male Wistar rats by collagen induced arthritis (CIA) method. BSE was administered at doses of 100 and 200mg/kg body weight once daily for 21 days. The effects of treatment in the rats were assessed by biochemical (articular elastase, MPO, LPO, GSH, catalase, SOD and NO), inflammatory mediators (IL-1β, IL-6, TNF-α, IL-10, IFN-γ and PGE2), and histological studies in joints. BSE was effective in bringing significant changes on all the parameters (articular elastase, MPO, LPO, GSH, catalase, SOD and NO) studied. Oral administration of BSE resulted in significantly reduced levels of inflammatory mediators (IL-1β, IL-6, TNF-α, IFN-γ and PGE2), and increased level of IL-10. The protective effects of BSE against RA were also evident from the decrease in arthritis scoring and bone histology. The abilities to inhibit proinflammatory cytokines and modulation of antioxidant status suggest that the protective effect of Boswellia serrata extract on arthritis in rats might be mediated via the modulation of immune system.

Attenuation of collagen induced arthritis via suppression on Th17 response by activating cholinergic anti-inflammatory pathway with nicotine

The cholinergic anti-inflammatory pathway can inhibit the inflammation of collagen induced arthritis (CIA), a mouse model of rheumatoid arthritis (RA). However, the immunologic mechanisms that provide a therapeutic effect against the auto-inflammatory disease are not yet elucidated. The present study explores the effect of cholinergic anti-inflammatory pathway on CD4+ T cell responses in CIA. Forty DBA/1 mice were divided into 4 groups: a control group, a CIA group, a vagotomy group, and a nicotine group. The degree of arthritis was measured by arthritis score and hematoxylin and eosin. ELISA was used to detect the serum concentration of IFN-γ, IL-4 and IL-17A. Flow cytometry was used to detect the cytokines and transcription factors (TFs) (the TFs of Th1, Th2, and Th17 cells are T-bet, RORγτ and GATA3 respectively) in the spleen. Immunohistochemistry was used to analyze RORγτ expression in the joint synovium. Arthritis in the nicotine group was significantly lightened compared with that in the CIA group and in the vagotomy group. Nicotine attenuated Th17 lineage by reducing IL-17A production and RORγτ expression. The expressions of IL-4 and GATA3 were increased in the same setting. However, the expressions of IFN-γ and T-bet had no difference between the nicotine and the CIA group. Nicotine may induce a shift to the Th2 lineage and improve the Th1/Th2 imbalance. Activating the cholinergic anti-inflammatory pathway with nicotine can inhibit Th17 cell responses and may improve the Th1/Th2 imbalance in CIA, providing a new justification for its application in the treatment of rheumatoid arthritis.

Partial depletion of natural gut flora by antibiotic aggravates collagen induced arthritis (CIA) in mice

BACKGROUND

Rheumatoid arthritis (RA) is a chronic inflammatory disease that affects about 1% of the adult population and occurs twice as frequently among women than men. At present it is accepted that pathogenesis of RA is based on inflammatory response mediated by CD4(+) Th1 and Th17 lymphocytes. The most commonly applied model imitating RA is the collagen induced arthritis (CIA). A growing evidence shows that there is a correlation between microbial dysbiosis and human pathology which includes autoimmunity, allergic diseases, obesity, inflammatory bowel disease (IBD), metabolic syndrome.

METHODS

Collagen induced arthritis was used to study influence of natural gut flora on course of rheumatoid arthritis.

RESULTS

Current work employing CIA model showed that partial depletion of natural gut flora with orally administered antibiotic Baytril (enrofloxacin) aggravates disease severity when compared to control mice. Observed partial depletion of both aerobic and anaerobic bacteria did not affect animal body weight. Additionally, in vitro study showed increased production of IFN-? and IL-17A and decreased release of IL-4 by axillary lymph node cells (ALNC) isolated from mice treated with antibiotic and induced CIA when compared to positive control. Furthermore, treatment with antibiotic prior to CIA induction results in augmented production of IFN-?, IL-17A and IL-6 by mesenteric lymph node cells (MLNC).

CONCLUSION

Presented data suggest that alteration of gut microbiota via use of enrofloxacin may play a role in modulating arthritis symptom severity in this mouse model.

Protective effects of Huang-Lian-Jie-Du-Tang and its component group on collagen-induced arthritis in rats

ETHNOPHARMACOLOGICAL RELEVANCE

Huang-Lian-Jie-Du-Tang is a famous Traditional Chinese medicine consisting of Rhizoma coptidis (Coptis chinensis Franch, Ranunculaceae), Radix scutellariae (Scutellaria baicalensis Georgi, Labiatae), Cortex phellodendri (Phellodendron amurense Rupr. Rutaceae) and Fructus gardeniae (Gardenia jasminoide Ellis, Rubiaceae) in a weight ratio of 3:2:2:3.This formula was described by Wang Tao (in the Chinese Tang Dynasty) in his treatise "Wai Tai Mi Yao". It has been used to treat inflammation, hypertension, gastrointestinal disorders, and liver and cerebrovascular diseases in the clinical practice of Traditional Chinese medicine, especially in treating inflammation for nearly two thousand years. However, the essential compounds in it have not been identified, and the mechanisms remain to be addressed. To investigate the protective effects of HLJDT and its component group (HLJDT-CG) on collagen-induced arthritis in rats.

MATERIALS AND METHODS

CIA was established in male Wistar rats with subcutaneous injection of type II bovine collagen at the base of the tail of animals. CIA rats were treated daily with oral administration of HLJDT aqueous extracts (270 mg/kg) or HLJDT-CG (40 mg/kg) once per day from day 6 to day 28. Rats in normal and vehicle control groups were given an equal volume of vehicle (0.9% saline) and 0.025 mg/kg Dexamethasone was given to the Standard group at the same time. The protective effect of them were assessed by measuring arthritis index, swelling, the cytokines such as TNF-α, IFN-γ and IL-17 in serum, type II collagen antibodies, splenocyte proliferation and so on.

RESULTS

The results demonstrated that treatment of CIA rat with either HLJDT aqueous extracts or HLJDT-CG not only ameliorated the symptoms of arthritis, prevented joint damage but also reduced the serum levels of TNF-α, IFN-γ and IL-17 in CIA rats. Anti-CII antibodies showed the similar trend except that of IgG1. Furthermore, HLJDT aqueous extracts and HLJDT-CG administration also suppressed CII-induced proliferative response of splenocytes. More importantly, HLJDT-CG exhibited similar pharmacological activities as HLJDT aqueous extracts in all aforementioned experiments.

CONCLUSIONS

HLJDT aqueous extracts and HLJDT-CG could effectively ameliorate CII-induced arthritis and significantly suppress the immune response against CII with similar pharmacological efficacy. These findings suggest that HLJDT has therapeutic potential in RA treatment and HLJDT-CG can represent the effective-composite of HLJDT.

A combination of sinomenine and methotrexate reduces joint damage of collagen induced arthritis in rats by modulating osteoclast-related cytokines

OBJECTIVE

To analyze the combination therapy of Sinomenine (SIN) and Methotrexate (MTX) in rheumatoid arthritis (RA), we herein demonstrated the combination effect of SIN and MTX on collagen-induced arthritis (CIA) in rats through their modulation on osteoclast-related cytokines.

METHODS

CIA was induced by the immunization of type II collagen (CII) in SD rats. SIN and MTX were administrated alone or in combination after the onset of arthritis. Arthritis index and histological analysis were used to evaluate the effect of treatments. Effects of SIN and MTX on expression of receptor activator of NF-κB ligand (RANKL) and osteopontin (OPN) in synovial tissues were assayed by immunohistochemistry. RANKL, osteoprotegerin (OPG), IL-6, IL-17 and matrix metalloproteinases (MMPs) in rat serum were measured by ELISA. The expression of osteoclast-related cytokines in fibroblast-like synoviocytes (FLS) from RA patients was assayed by RT-PCR.

RESULTS

SIN and MTX combination additively reduced the inflammatory symptoms and joint damage in CIA. Combination of SIN and MTX significantly repressed synovial RANKL and OPN production. SIN and MTX exhibited complementary and synergistic effect upon down-regulating RANKL, IL-6, IL-17 and MMPs in rat serum. SIN and MTX also modulated the expression of RANKL and OPG in RA-FLS.

CONCLUSION

SIN and MTX have additive effects, decreasing inflammation and joint damage in CIA rats by modulating osteoclast-related cytokines. These results are indicative of the combined effect of SIN and MTX for anti-arthritic treatment in RA.

Quantification of bone changes in a collagen-induced arthritis mouse model by reconstructed three dimensional micro-CT

Background

Inflammatory arthritis is a chronic disease, resulting in synovitis and subchondral and bone area destruction, which can severely affect a patient’s quality of life. The most common form of inflammatory arthritis is rheumatoid arthritis (RA) in which many of the disease mechanisms are not well understood. The collagen-induced arthritis (CIA) mouse model is similar to RA as it exhibits joint space narrowing and bone erosion as well as involves inflammatory factors and cellular players that have been implicated in RA pathogenesis. Quantitative data for disease progression in RA models is difficult to obtain as serum blood markers may not always reflect disease state and physical disease indexes are subjective. Thus, it is important to develop tools to objectively assess disease progression in CIA.

Results

Micro-CT (Computed Tomography) is a relatively mature technology that has been used to track a variety of anatomical changes in small animals. In this study, micro-CT scans of several joints of control and CIA mice were acquired at 0, 4, 7, and 9 weeks after the immunization with collagen type II. Each micro-CT scan was analyzed by applying a segmentation algorithm to individual slices in each image set to provide 3-dimensional representations of specific bones including the humerus, femur, and tibia. From these representations, the volume and mean density of these bones were measured and compared. This analysis showed that both the volume and the density of each measured bone of the CIA mice were significantly smaller than those of the controls at week 7.

Conclusions

This study demonstrates that micro-CT can be used to quantify bone changes in the CIA mouse model as an alternative to disease index assessments. In conclusion, micro-CT could be useful as a non-invasive method to monitor the efficacy of new treatments for RA tested in small animals.

Characterization of chemically defined poly-N-isopropylacrylamide based copolymeric adjuvants

PNiPAAm is a thermo-responsive polymer with an adjuvant activity. To identify the minimal chemical structure present within PNiPAAm responsible for its adjuvant property, three different constituent polymers with specific functional groups were synthesized through free radical reaction and tested their adjuvant potential along with PNiPAAm. Among them, polymer with isopropyl attached to an amide showed maximal adjuvant activity in rodents followed by polymer with amide or ketone functional groups. However, secondary amine containing polymer did not show any adjuvant activity. In addition, to improve the adjuvant properties of PNiPAAm, we incorporated an affinity ligand, boronate. At first, we synthesized and characterized the dual responsive copolymers PNiPAAm-co-VPBA and PNiPAAm-co-VPBA-co-DMAEMA. Biocompatibility of these copolymers was confirmed both in vitro and in vivo. Mice injected with these copolymers mixed with collagen (CII) developed significant levels of anti-CII antibodies comprising of all the major IgG subclasses and an increased T cell activation. At the injection site, massive infiltration of immune cells was observed. However, only PNiPAAm-co-VPBA-co-DMAEMA-CII induced arthritis in mice after injection of 0.5M fructose confirming the importance of effective release of CII from the polymer for its adjuvant activity. Thus, a fine balance of hydrophobicity and hydrophilicity promotes adjuvant properties and continuous release of antigen, in this case CII, from polymer is essential for its adjuvant activity.

Gene Expression Profile of T-cell Receptors in the Synovium, Peripheral Blood, and Thymus during the Initial Phase of Collagen-induced Arthritis

Background

Current management strategies attempt to diagnose rheumatoid arthritis (RA) at an early stage. Transcription profiling is applied in the search for biomarkers for detecting early-stage disease. Even though gene profiling has been reported using several animal models of RA, most studies were performed after the development of active arthritis, and conducted only on the peripheral blood and joint. Therefore, we investigated gene expression during the initial phase of collagen-induced arthritis (CIA) before the arthritic features developed in the thymus in addition to the peripheral blood and synovium.

Methods

For gene expression analysis using cDNA microarray technology, samples of thymus, blood, and synovium were collected from CIA, rats immunized only with type II collagen (Cll), rats immunized only with adjuvant, and unimmunized rats on days 4 and 9 after the first immunization. Arrays were scanned with an Illumina bead array.

Results

Of the 21,910 genes in the array, 1,243 genes were differentially expressed at least 2-fold change in various organs of CIA compared to controls. Among the 1,243 genes, 8 encode T-cell receptors (TCRs), including CD3ζ, CD3δ, CD3ε, CD8α, and CD8β genes, which were down-regulated in CIA. The synovium was the organ in which the genes were differentially expressed between CIA and control group, and no difference were found in the thymus and blood. Further, we determined that the differential expression was affected by adjuvant more than Cll. The differential expression of genes as revealed by real-time RT-PCR, was in agreement with the microarray data.

Conclusion

This study provides evidence that the genes encoding TCRs including CD3ζ, CD3δ, CD3ε, CD8α, and CD8β genes were down-regulated during the initial phase of CIA in the synovium of CIA. In addition, adjuvant played a greater role in the down-regulation of the CD3 complex compared to CII. Therefore, the down-regulation of TCR gene expression occurred dominantly by adjuvant could be involved in the pathogenesis of the early stage at CIA.