Collagen-induced arthritis, an animal model of autoimmunity

Osteostatin Mitigates Gouty Arthritis through the Inhibition of Caspase-1 Activation and Upregulation of Nrf2 Expression

Gouty arthritis results from monosodium urate (MSU) crystal deposition in joints, initiating (pro)-interleukin (IL)-1β maturation, inflammatory mediator release, and neutrophil infiltration, leading to joint swelling and pain. Parathyroid hormone-related protein (107-111) C-terminal peptide (osteostatin) has shown anti-inflammatory properties in osteoblasts and collagen-induced arthritis in mice, but its impact in gouty arthritis models remains unexplored. We investigated the effect of osteostatin on pyroptosis, inflammation, and oxidation in macrophages, as well as its role in the formation of calcium pyrophosphate dihydrate crystals and MSU-induced gouty arthritis in mice models. Osteostatin ameliorated pyroptosis induced by lipopolysaccharide and adenosine 5'-triphosphate (LPS + ATP) in mice peritoneal macrophages by reducing the expression of caspase-1, lactate dehydrogenase release, and IL-1β and IL-18 secretion. Additionally, IL-6 and tumor necrosis factor-α (TNF-α) were also decreased due to the reduced activation of the NF-κB pathway. Furthermore, osteostatin displayed antioxidant properties in LPS + ATP-stimulated macrophages, resulting in reduced production of mitochondrial and extracellular reactive oxygen species and enhanced Nrf2 translocation to the nuclei. In both models of gouty arthritis, osteostatin administration resulted in reduced pro-inflammatory cytokine production, decreased leukocyte migration, and reduced caspase-1 and NF-κB activation. These results highlight the potential of osteostatin as a therapeutic option for gouty arthritis.

Sex hormone signaling and regulation of immune function

Immune responses to antigens, including innocuous, self, tumor, microbial, and vaccine antigens, differ between males and females. The quest to uncover the mechanisms for biological sex differences in the immune system has intensified, with considerable literature pointing toward sex hormonal influences on immune cell function. Sex steroids, including estrogens, androgens, and progestins, have profound effects on immune function. As such, drastic changes in sex steroid concentrations that occur with aging (e.g., after puberty or during the menopause transition) or pregnancy impact immune responses and the pathogenesis of immune-related diseases. The effect of sex steroids on immunity involves both the concentration of the ligand and the density and distribution of genomic and nongenomic receptors that serve as transcriptional regulators of immune cellular responses to affect autoimmunity, allergy, infectious diseases, cancers, and responses to vaccines. The next frontier will be harnessing these effects of sex steroids to improve therapeutic outcomes.

Administration of Recombinant TAPBPL Protein Ameliorates Collagen-Induced Arthritis in Mice

Rheumatoid arthritis (RA) is a chronic inflammatory autoimmune disease distinguished by synovial hyperplasia and a progressive destruction of joints. T cells are critical players in the pathogenesis of RA. We have previously identified a novel immune checkpoint molecule, TAPBPL, that inhibits T cell functions in vitro. As a model for human RA, we investigated the ability of the TAPBPL protein to ameliorate collagen type II (CII)-induced arthritis (CIA) in mice that were injected with recombinant TAPBPL or a control protein. The mice were analyzed for CIA development, immune cells, and their responses. We found that TAPBPL protein significantly decreased CIA incidence and reduced clinical and pathological arthritis scores, which were related to a lower number of activated CD4 T cells but a greater number of regulatory T cells (Tregs) in the spleen, and a reduction of Th1/Th17 inflammatory cytokines in the joints and serum. Importantly, TAPBPL protein inhibited CII-specific T cell growth and Th1 and Th17 cytokine expression and reduced the production of CII autoantibodies in the serum. Our results suggest that TAPBPL protein can ameliorate CIA in mice and has the potential to be used in the treatment of patients with RA.

Ocimum sanctum L water extract: In-situ green synthesis of zinc oxide nanoparticles for treatment of rheumatoid arthritis: Preclinical study

BACKGROUND AND OBJECTIVE

Rheumatoid arthritis is a chronic progressive autoimmune disorder, characterised by destruction of cartilage and under line bones. Though exact etiology of rheumatoid arthritis (RA) remains unknown. It is believed that alteration in control of cellular or molecular responses is involved in the chronic inflammation. Earlier in RA patients it was observed the circulating RA specific biomarkers and immunoglobulin deposits in the synovial joints. Zinc Oxide Nanoparticles (ZnO NPs) is used as an anti-inflammatory and anticancer agent, however there is nil/very less scientific data shows the anti-arthritic activity of green synthesis ZnO nanoparticles (Ocimum sanctum water extract in-situ synthesis of ZnO NPs having active compound Caffeic acid and Rosmerinic acid). Hence, the present activity was planned to assess the anti-arthritic activity of ZnO NPs in CIA rats.

METHODS

Arthritis in rats were induced by subcutaneous injection of collagen type II (CII) (200 µl) at the base of tail on day 0 followed by booster dose on day 14. ZnO NPs were given (2 mg/kg b.wt./day) orally for 20 days. At the end of the study serum, joint homogenate was used to assess the level of biomarkers (RF, a-CCP, a-CII and CRP) and inflammatory mediators. In addition, m-RNA expression of various genes such as Nuclear factor-kB (NF-kB), inflammatory mediators like tumour necrosis factor-α (TNF-α), cyclooxygenase-2 (COX-2) etc. were assayed in joint tissue. Finally all these biochemical and molecular results were confirmed by microscopic study of joint tissue.

RESULTS

ZnO NPs, treated rats showed decrease in inflammation and clinical severity. This was related with decrease in the level of biomarkers (like RF, a-CCP and CRP), inflammatory mediators (TNF-α, COX-2) and activity of transcription factor NF-kB. All these findings were positively correlated with microscopic analysis of joint tissue that showed reduced inflammation and bone erosion in treated group.

CONCLUSION

This study validates the anti-arthritic activity of ZnO NPs as it mitigates the arthritis related symptoms in CIA rats.

1,25-Dihydroxyvitamin D3 and 20-Hydroxyvitamin D3 Upregulate LAIR-1 and Attenuate Collagen Induced Arthritis

Vitamin D plays a crucial role in regulation of the immune response. However, treatment of autoimmune diseases with 1,25-dihydroxyvitamin D3 [1,25(OH)₂D3] doses sufficient to be effective is prohibitive due to its calcemic and toxic effects. We use the collagen-induced arthritis (CIA) model to analyze the efficacy of the noncalcemic analog of vitamin D, 20S-hydroxyvitamin D3 [20S(OH)D3], as well as 1,25(OH)₂D3, to attenuate arthritis and explore a potential mechanism of action. Mice fed a diet deficient in vitamin D developed a more severe arthritis characterized by enhanced secretion of T cell inflammatory cytokines, compared to mice fed a normal diet. The T cell inflammatory cytokines were effectively suppressed, however, by culture of the cells with 20S(OH)D3. Interestingly, one of the consequences of culture with 1,25(OH)₂D3 or 20S(OH)D3, was upregulation of the natural inhibitory receptor leukocyte associated immunoglobulin-like receptor-1 (LAIR-1 or CD305). Polyclonal antibodies which activate LAIR-1 were also capable of attenuating arthritis. Moreover, oral therapy with active forms of vitamin D suppressed arthritis in LAIR-1 sufficient DR1 mice, but were ineffective in LAIR-1^−/− deficient mice. Taken together, these data show that the effect of vitamin D on inflammation is at least, in part, mediated by LAIR-1 and that non-calcemic 20S(OH)D3 may be a promising therapeutic agent for the treatment of autoimmune diseases such as Rheumatoid Arthritis.

Actions and Therapeutic Potential of Madecassoside and Other Major Constituents of Centella asiatica: A Review

Centella asiatica is a popular herb well-known for its wide range of therapeutic effects and its use as a folk medicine for many years. Its therapeutic properties have been well correlated with the presence of asiaticoside, madecassoside, asiatic and madecassic acids, the pentacyclic triterpenes. The herb has been extensively known to treat skin conditions; nevertheless, several pre-clinical and clinical studies have scientifically demonstrated its effectiveness in other disorders. Among the active constituents that have been identified in Centella asiatica, madecassoside has been the subject of only a relatively small number of scientific reports. Therefore, this review, while including other major constituents of this plant, focuses on the therapeutic potential, pharmacokinetics and toxicity of madecassoside.

Inhibition of glycolysis in the presence of antigen generates suppressive antigen-specific responses and restrains rheumatoid arthritis in mice

Dendritic cells (DCs) rely on glycolysis for their energy needs to induce pro-inflammatory antigen-specific immune responses. Therefore, inhibiting DC glycolysis, while presenting the self-antigen, may prevent pro-inflammatory antigen-specific immune responses. Previously we demonstrated that microparticles with alpha-ketoglutarate (aKG) in the polymer backbone (paKG MPs) were able to generate anti-inflammatory DCs by sustained delivery of the aKG metabolite, and by modulating energy metabolism of DCs. Herein, we demonstrate that paKG MPs-based delivery of a glycolytic inhibitor, PFK15, using paKG MPs induces anti-inflammatory DCs (CD86^LoMHCII⁺) by down-regulating glycolysis, CD86, tnf and IL-6 genes, while upregulating oxidative phosphorylation (OXPHOS) and mitochondrial genes. Furthermore, paKG MPs delivering PFK15 and a self-antigen, collagen type II (bc2), in vivo, in a collagen-induced autoimmune arthritis (CIA) mouse model, normalized paw inflammation and arthritis score, by generating antigen-specific immune responses. Specifically, these formulations were able to reduce activation of DCs in draining lymph nodes and impressively generated proliferating bc2-specific anti-inflammatory regulatory T cells in joint-associated popliteal lymph nodes. These data strongly suggest that sustained glycolytic inhibition of DCs in the presence of an antigen can induce antigen-specific immunosuppressive responses, therefore, generating a technology that can be applicable for treating autoimmune diseases.

Pharmacokinetics-Based Chronoefficacy of Semen Strychni and Tripterygium Glycoside Tablet Against Rheumatoid Arthritis

Rheumatoid arthritis is a systemic autoimmune disease characterized by synovial inflammation and bone destruction. Identifying drugs with time-varying efficacy and toxicity, and elucidating the mechanisms would help to improve treatment efficacy and reduce adverse effects. Here, we aimed to determine the chronoefficacy of semen strychni (SS) and tripterygium glycoside tablet (TGT) against rheumatoid arthritis in mice, and to investigate a potential role of circadian pharmacokinetics in generating chronoefficacy. SS extract and TGT suspension were prepared with ultrasonication. Effects of SS and TGT on collagen-induced arthritis (CIA) were evaluated by measuring TNF-α and IL-6 levels. SS dosed at ZT18 was more effective in protecting against CIA than drug dosed at ZT6 (i.e., lower levels of key inflammatory factors at ZT18 than at ZT6). This was accompanied by higher systemic exposure levels of strychnine and brucine (two main putative active ingredients of SS) in ZT18-treated than in ZT6-treated CIA mice. TGT dosing at ZT2 showed a better efficacy against CIA as compared to herb doing at ZT14. Consistently, ZT2 dosing generated a higher exposure of triptolide (a main putative active ingredient of TGT) as compared to ZT14 dosing in CIA mice. Moreover, strychnine, brucine, and triptolide significantly inhibited the proliferation of fibroblast-like synoviocytes, and reduced the production of TNF-α and IL-6 and the mRNAs of TNF-α, IL-6, COX-2, and iNOS, suggesting that they possessed an anti-arthritis activity. In conclusion, SS and TGT display chronoefficacy against rheumatoid arthritis in mice, that is attributed to circadian pharmacokinetics of main active ingredients. Our findings have implications for improving treatment outcomes of SS and TGT via timed delivery.

Recombinant CD300c-Fc fusion protein attenuates collagen-induced arthritis in mice

OBJECTIVES

Rheumatoid arthritis (RA) is a chronic autoimmune disease characterized by joint inflammation and tissue destruction. Immune responses mediated by T cells and autoantibodies are known to play critical roles in RA. Collagen type II (CII)-induced arthritis (CIA) is a commonly used animal model of human RA. We have previously reported the identification of a new T cell inhibitory molecule CD300c. Here we investigate the ability of recombinant CD300c-IgG2a Fc (CD300c-Ig) fusion protein to prevent and treat CIA.

METHODS

Mice were induced to develop CIA by CII and injected with CD300c-Ig or control Ig protein before or after CIA symptoms occur. The mice were examined for CIA clinical and pathological scores, and analyzed for the expression of proinflammatory cytokines, the percentage and activation of CD4 T cells and regulatory T cells, CII-specific T cell proliferation and cytokine production, and CII-specific autoantibody production.

RESULTS

In a prevention model, CD300c-Ig significantly decreases CIA incidence, and reduces clinical and pathological arthritis scores. In the treatment model, CD300c-Ig ameliorates established CIA. The beneficial effects of CD300c-Ig are related to decreased expansion and activation of T cells in the spleen and reduced expression of proinflammatory cytokines in the joints. CD300c-Ig also inhibits CII-specific T cell proliferation and Th1 and Th17 cytokine production. In addition, CD300c-Ig treatment reduced the production of CII autoantibodies in the serum. Furthermore, CD300c-Ig inhibits the proliferation and activation of T cells from RA patients in vitro.

CONCLUSION

CD300c-Ig protein has the potential to be used in the treatment of patients with RA.

New bitongling (NBTL) ameliorates rheumatoid arthritis in rats through inhibiting JAK2/STAT3 signaling pathway

Rheumatoid arthritis (RA) is featured by a variety of physical symptoms and fibroblast-like synoviocytes (FLSs) abnormal proliferation. Increasing evidence has demonstrated that traditional Chinese medicine exerts an important role in RA treatment. New bitongling (NBTL) as one of the traditional Chinese medicine has been reported to be involved in the progression of RA, but the exact mechanism is unclear. In our study, we intended to investigate the effect of NBTL on RA to identify the mechanisms related to JAK2/STAT3 signaling pathway. Extracts of Tripterygium wilfordii (TW), a traditional Chinese herbal medicine, have been widely used for treating RA in China for several decades, so, TW was used as a positive control drug for TBNL. RA rats were constructed by immunization with collagen type II to evaluate the action of NBTL in vivo. Body weight and arthritic index were evaluated. Hematoxylin and Eosin staining was performed to analysis the morphological changes of ankle joints tissue. TUNEL and flow cytometry were performed to examine cell apoptosis, while CCK8 and Ethynyl-2'-deoxyuridine (EdU) were performed to examine cell proliferation. In addition, the markers of inflammation were detected by Western blot, ELISA, and RT-qPCR. Firstly, we find that rats treated with NBTL or TW not only reduced swelling degree and bone destruction, but also repressed IL-1 β and IL-6 levels. In addition, NBTL and TW could increase the weight of rats, and promote the level of IL-10 and IL-4 in vivo. Furthermore, NBTL inhibited inflammation of FLS, induced cell apoptosis and hindered cell proliferation, which was reversed by dipeptidyl peptidase (DPP), a JAK2/STAT3 pathway activator. Taken together, NBTL potentially retarded RA via JAK2/STAT3 pathway, highlighting novel mechanisms associated with RA.

Pharmacokinetics of metformin in collagen-induced arthritis rats

Due to the elevated presence of cytokines, the expressions of metabolic enzymes and drug transporters are altered in rheumatoid arthritis (RA). Given the high incidence of diabetes in patients with RA, the aim of the present study was to investigate the metformin pharmacokinetics of a single oral dose in rats with collagen-induced arthritis (CIA). Blood and urine samples were collected at different timepoints, and analyzed by ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS). Tissue samples were also collected to investigate the expression of metabolic enzymes and drug transporters by quantitative reverse transcription-polymerase chain reaction (RT-qPCR) and western blot. The results indicated that the bioavailability of metformin was markedly decreased in the CIA rats. Moreover, metformin was not metabolized by enzymes of rat liver microsomes, suggesting that the decreased bioavailability of metformin was independent of the liver metabolism. In addition, the mRNA, protein expression level and activity of the renal organic cation transporter 2 (OCT2) was markedly increased, suggesting that the enhanced renal clearance of metformin in CIA rats may be due to the up-regulated activity of OCT2. In conclusion, our study suggested that the reduced bioavailability of metformin in CIA rats is possibly related to the up-regulated function of the renal protein OCT2.

Acetazolamide ameliorates the severity of collagen-induced arthritis in rats: Involvement of inducing synovial apoptosis and inhibiting Wnt/β-catenin pathway

We previously revealed that the overexpression of synovial aquaporin 1 (AQP1) aggravated collagen-induced arthritis (CIA) in rats via regulating β-catenin signaling. This study was to demonstrate the therapeutic effect of acetazolamide (AZ, an AQP1 inhibitor) on rat CIA and explored its underlying mechanisms. Paw swelling, arthritis index, pathological assessments, and serum levels of collagen type II (Col II) antibody, IL-1β and TNF-α were measured to evaluate the anti-arthritic effect of AZ on rat CIA. Ki67 immunohistochemistry and TUNEL assay were performed to reveal the anti-proliferative and pro-apoptotic effects of AZ on synovial cells in vivo. The protein levels of apoptosis-related genes and Wnt/β-catenin pathway key members were detected by western blot. We found that AZ treatment on CIA rats could inhibit paw swelling, reduce arthritis index, alleviate the pathologic changes of ankle joint and decrease the serum levels of Col II antibody, TNF-α and IL-1β. AZ could reduce Ki67 expression and increase apoptosis index in CIA synovial tissues by reducing Bcl-2 protein level, increasing Bax and caspase 3 protein levels and normalizing Bcl-2/Bax ratio. Moreover, AZ could reduce the protein levels of Wnt1, β-catenin, p-GSK-3β (Ser9), c-myc, cyclin D1 and MMP9, while increase GSK-3β protein level in CIA synovial tissues. Importantly, these mentioned effects of AZ (60 mg/kg) on CIA rats could be reversed by the combined use of lithium chloride (LiCl), an activator of Wnt/β-catenin pathway. In short, AZ exerted potent anti-arthritic effects on CIA rats by inducing synovial apoptosis and inhibiting Wnt/β-catenin pathway.

Inhibitory activity of gintonin on inflammation in human IL-1β-stimulated fibroblast-like synoviocytes and collagen-induced arthritis in mice

Background

Gintonin is a newly derived glycolipoprotein from the roots of ginseng. The purpose of this study is to investigate the anti-arthritic efficacy of Gintonin on various proteases and inflammatory mediators that have an important role in arthritis.

Methods

Fibroblast-like synoviocytes (FLS) were treated with Gintonin and stimulated with interleukin (IL)-1β 1 hour later. The antioxidant effect of Gintonin was measured using MitoSOX and H₂DCFDA experiments. The anti-arthritic efficacy of Gintonin was examined by analyzing the expression levels of inflammatory mediators using RT-PCR, western blot, and ELISA. The phosphorylation of mitogen-activated protein kinase (MAPK) pathways and translocation of nuclear factor kappa B (NF-κB)/p65 into the nucleus were also analyzed using western blot, ELISA, and immunocytochemistry. Collagen-induced arthritis (CIA) mice model was used. Mice were orally administered with Gintonin (25, 50, and 100 mg/kg) every 2 days for 45 days. The body weight, arthritis score, squeaking score, and paw volume were measured as the behavioral parameters. After sacrifice, H&E and safranin-O staining were performed for histological analysis.

Results

Gintonin significantly inhibited the expression of inflammatory intermediates. Gintonin prevented NF-κB/p65 from moving into the nucleus through the JNK and ERK MAPK phosphorylation in FLS cells. Moreover, Gintonin suppressed the symptoms of arthritis in the CIA mice model.

Conclusion

As a result, the antioxidant and anti-inflammatory effects of Gintonin were demonstrated, and ultimately the anti-arthritic effect was proved. Collectively, Gintonin has a great potential as a therapeutic agent for arthritis treatment.

Role of glucose metabolism in aggressive phenotype of fibroblast-like synoviocytes: Latest evidence and therapeutic approaches in rheumatoid arthritis

Glucose metabolism is considerably increased in inflamed joints of rheumatoid arthritis (RA) patients at early stages. Fibroblast-like synoviocytes (FLSs) activation and subsequent joint damage are linked with metabolic alterations, especially glucose metabolism. It has been shown that glucose metabolism is elevated in aggressive phenotype of FLS cells. In this regard, glycolytic blockers are able to reduce aggressiveness of the FLS cells resulting in decreased joint damage in various arthritis models. Besides, metabolic changes in immune and non-immune cells such as FLS can provide important targets for therapeutic intervention. Glycolytic enzymes such as hexokinase 2 (HK2), phosphofructo-2-kinase/fructose-2,6-bisphosphatase (PFKFB), and phosphoglycerate kinase (PGK) play essential roles in aggressive behavior of FLS cells. It has been documented that the HK2 enzyme is significantly upregulated in RA FLS cells, compared with osteoarthritis (OA) FLS cells. The HK2 is expressed in a few tissues and upregulated in the inflamed synovium of RA patients that makes it a potential target for RA treatment. Furthermore, HK2 has different roles in each cellular compartment, which offers another level of specificity and provides a specific target to reduce deleterious effects of inhibiting the enzyme in RA without affecting glycolysis in normal cells. Thus, targeting the HK2 enzyme might be an attractive potential selective target for arthritis therapy and safer than global glycolysis inhibition. Therefore, this review was aimed to summarize the current knowledge about glucose metabolism of FLS cells and suggest novel biomarkers, which are potential candidates for RA treatment.

Anti-angiogenic effect of Shikonin in rheumatoid arthritis by downregulating PI3K/AKT and MAPKs signaling pathways

ETHNOPHARMACOLOGICAL RELEVANCE

Zicao is the dried root of Lithospermum erythrorhizon Sieb, et Zucc, Arnebia euchroma (Royle) Johnst, or Arnebia guttata Bunge and commonly used to treat viral infection, inflammation, arthritis and cancer in China.Shikonin (SKN) is a major active chemical component isolated from zicao. Previous research showed that SKN has anti-inflammatory, immunomodulatory and analgesic effects, and inhibits the development of arthritis and the condition of collagen arthritis (CIA) mice; nevertheless, its role in the angiogenesis of rheumatoid arthritis (RA) has not been elucidated.

AIM OF THE STUDY

The purpose of this study was to investigate the antiangiogenic activity of SKN in CIA rats and various angiogenesis models.

MATERIAL AND METHODS

The anti-arthritic effect of SKN on CIA rats was tested by arthritis score, arthritis incidence, radiological observation and histopathology evaluation of inflamed joints. Vessel density evaluated with CD31 immunohistochemistry/immunofluorescence in joint synovial membrane tissues of CIA rats, chick chorioallantoic membrane assay, rat aortic ring assay, and the migration, invasion, adhesion and tube formation of human umbilical vein endothelial (HUVEC) cells induced by tumor necrosis factor (TNF)-α were used to measured the antiangiogenenic activity of SKN. Moreover, the effect of SKN on the expression of angiogenic mediators, such as vascular endothelial growth factor (VEGF), VEGFR2, TNF-α, interleukin (IL)-1β, platelet derived growth factor (PDGF) and transforming growth factor (TGF)-β in sera and joint synovia of rats, and in TNF-α-induced MH7A/HUVEC cells were measured by immunohistochemistry, enzyme linked immunosorbent assay, Western blot and/or real-time polymerase chain reaction (PCR). Through the analysis of protein and mRNA levels of phosphoinositide 3-kinase (PI3K), Akt and PTEN, and the autophosphorylation of ERK1/2, JNK and p38 in joint synovia of rats and in TNF-α-induced HUVEC cells, the molecular mechanism of its inhibition was elucidated by using Western blot and/or real-time PCR.

RESULTS

SKN significantly reduced the arthritis score and arthritis incidence, and inhibited inflammation, pannus formation, cartilage and bone destruction of inflamed joints in CIA rats. Partially, SKN remarkably decreased the immature blood vessels in synovial membrane tissues of inflamed joints from CIA rats. It also suppressed in vivo angiogenesis in chick embryo and VEGF₁₆₅-induced microvessel sprout formation ex vivo. Meanwhile, SKN inhibited TNF-α-induced migration, invasion, adhesion and tube formation of HUVEC cells. Moreover, SKN significantly decreased the expression of angiogenic activators including VEGF, VEGFR2, TNF-α, IL-1β, PDGF and TGF-β in synovia of CIA rats and/or in MH7A/HUVEC cells. More interestingly, SKN downregulated PI3K and Akt, and simultaneously upregulated PTEN both at protein and mRNA levels in synovia tissues and/or in TNF-α-induced HUVEC cells. It also suppressed the phosphorylation and gene level of TNF-α-induced signaling molecules, as ERK1/2, JNK, and p38 in synovium and/or in TNF-α-induced HUVEC cells.

CONCLUSION

These findings indicate for the first time that SKN has the anti-angiogenic effect in RA in vivo, ex vivo and in vitro by interrupting the PI3K/AKT and MAPKs signaling pathways.

Therapeutic Effects of Tryptanthrin and Tryptanthrin-6-Oxime in Models of Rheumatoid Arthritis

Rheumatoid arthritis (RA) is a chronic autoimmune disease involving joint and bone damage that is mediated in part by proteases and cytokines produced by synovial macrophages and fibroblast-like synoviocytes (FLS). Although current biological therapeutic strategies for RA have been effective in many cases, new classes of therapeutics are needed. We investigated anti-inflammatory properties of the natural alkaloid tryptanthrin (TRYP) and its synthetic derivative tryptanthrin-6-oxime (TRYP-Ox). Both TRYP and TRYP-Ox inhibited matrix metalloproteinase (MMP)-3 gene expression in interleukin (IL)-1β-stimulated primary human FLS, as well as IL-1β–induced secretion of MMP-1/3 by FLS and synovial SW982 cells and IL-6 by FLS, SW982 cells, human umbilical vein endothelial cells (HUVECs), and monocytic THP-1 cells, although TRYP-Ox was generally more effective and had no cytotoxicity in vitro. Evaluation of the therapeutic potential of TRYP and TRYP-Ox in vivo in murine arthritis models showed that both compounds significantly attenuated the development of collagen-induced arthritis (CIA) and collagen-antibody–induced arthritis (CAIA), with comparable efficacy. Collagen II (CII)-specific antibody levels were similarly reduced in TRYP- and TRYP-Ox-treated CIA mice. TRYP and TRYP-Ox also suppressed proinflammatory cytokine production by lymph node cells from CIA mice, with TRYP-Ox being more effective in inhibiting IL-17A, granulocyte-macrophage colony-stimulating factor (GM-CSF), and receptor activator of nuclear factor-κB ligand (RANKL). Thus, even though TRYP-Ox generally had a better in vitro profile, possibly due to its ability to inhibit c-Jun N-terminal kinase (JNK), both TRYP and TRYP-Ox were equally effective in inhibiting the clinical symptoms and damage associated with RA. Overall, TRYP and/or TRYP-Ox may represent potential new directions for the pursuit of novel treatments for RA.

Influence of estradiol treatment on bone marrow cell differentiation in collagenase-induced arthritis

OBJECTIVE AND DESIGN

Estrogen is one of the important regulators of the balance between bone formation and bone resorption that can modulate the levels and activity of certain growth factors and cytokines. In this study, we investigated the effect of 17β-estradiol (ED) on bone marrow (BM) cell differentiation in vivo and ex vivo in a mouse model of collagenase-induced osteoarthritis (CIOA).

SUBJECT

ICR (CD-2) female mice were used in present experiments (total number = 75) and bone marrow cells were used for in vitro studies.

TREATMENT

Mice were orally fed under different schemes with 17β-estradiol at a dose of 2 μg or 4 μg for 30 days.

METHODS

The effect of estradiol was estimated by histopathological, flow cytometry, and ELISA assays. Statistical differences were determined by one-way ANOVA.

RESULTS

Estradiol treatment ameliorated cartilage destruction and osteophyte formation if started from day 0 of CIOA induction, attended with a decrease of uterine and ovarian weights. Long time treatment lowered the percentage of megakaryocyte/platelet (CD62P+) populations and osteoclast (RANK+) populations in BM. Cells obtained from estradiol-treated CIOA mice showed inhibited capacity to differentiate into RANK+ and mesenchymal cells under osteoclastogenic conditions in vitro. Estrogen decreased serum IL-6 levels.

CONCLUSION

Results indicate a potential protective role for estrogen against the development of OA.

Ameliorating effects of Gö6976, a pharmacological agent that inhibits protein kinase D, on collagen-induced arthritis

Toll-like receptor (TLR) signaling can contribute to the pathogenesis of arthritis. Disruption of TLR signaling at early stages of arthritis might thereby provide an opportunity to halt the disease progression and ameliorate outcomes. We previously found that Gö6976 inhibits TLR-mediated cytokine production in human and mouse macrophages by inhibiting TLR-dependent activation of protein kinase D1 (PKD1), and that PKD1 is essential for proinflammatory responses mediated by MyD88-dependent TLRs. In this study, we investigated whether PKD1 contributes to TLR-mediated proinflammatory responses in human synovial cells, and whether Gö6976 treatment can suppress the development and progression of type II collagen (CII)-induced arthritis (CIA) in mouse. We found that TLR/IL-1R ligands induced activation of PKD1 in human fibroblast-like synoviocytes (HFLS). TLR/IL-1R-induced expression of cytokines/chemokines was substantially inhibited in Gö6976-treated HFLS and PKD1-knockdown HFLS. In addition, serum levels of anti-CII IgG antibodies, and the incidence and severity of arthritis after CII immunization were significantly reduced in mice treated daily with Gö6976. Synergistic effects of T-cell receptor and TLR, as well as TLR alone, on spleen cell proliferation and cytokine production were significantly inhibited in the presence of Gö6976. Our results suggest a possibility that ameliorating effects of Gö6976 on CIA may be due to its ability to inhibit TLR/IL-1R-activated PKD1, which might play an important role in proinflammatory responses in arthritis, and that PKD1 could be a therapeutic target for inflammatory arthritis.

Inhibition of NET formation by polydatin protects against collagen-induced arthritis

BACKGROUND

Rheumatoid arthritis (RA) is a systematic, inflammatory, autoimmune disease, associated with a high number of disabilities. Increasing evidence has demonstrated that neutrophil extracellular trap (NET) formation plays a significant role in the pathogenesis and progression of RA. In this study, we have aimed to investigate the effects of polydatin (PD) on NET formation and its effects on disease activity in a collagen-induced arthritis (CIA) mouse model.

METHODS

In the presence of PD or vehicle, neutrophils isolated from RA patients and mice were treated with phorbol 12-myristate 13-acetate (PMA) for 4 h, and NET formation investigated. For in vivo experiments, PD was administered intraperitoneally (45 mg/kg per day) to collagen-induced arthritis (CIA) mice. The incidence and severity of collagen-induced arthritis were assessed and NET deposition tested.

RESULTS

In vitro, PD significantly suppressed NET formation of neutrophils from RA patients. Consistently, decreased NETs were observed in PD treated bone marrow-derived neutrophils. In CIA mouse model, PD treatment delayed the onset of arthritis and attenuated arthritis severity. Compared with vehicle-treated CIA mice, the deposition of NETs in ankle joints was also reduced in PD-treated CIA mice.

CONCLUSION

In this study, we found that PD treatment markedly inhibited NET formation and protected CIA mice from the development of arthritis. These findings suggest that inhibition of NET formation by PD may serve as a novel mechanism for the treatment of RA.

The Microbial Metabolite Trimethylamine N-Oxide Links Vascular Dysfunctions and the Autoimmune Disease Rheumatoid Arthritis

Diet and microbiota each have a direct impact on many chronic, inflammatory, and metabolic diseases. As the field develops, a new perspective is emerging. The effects of diet may depend on the microbiota composition of the intestine. A diet that is rich in choline, red meat, dairy, or egg may promote the growth, or change the composition, of microbial species. The microbiota, in turn, may produce metabolites that increase the risk of cardiovascular disease. This article reviews our current understanding of the effects of the molecule trimethylamine-N-oxide (TMAO) obtained from food or produced by the microbiota. We review the mechanisms of actions of TMAO, and studies that associate it with cardiovascular and chronic kidney diseases. We introduce a novel concept: TMAO is one among a group of selective uremic toxins that may rise to high levels in the circulation or accumulate in various organs. Based on this information, we evaluate how TMAO may harm, by exacerbating inflammation, or may protect, by attenuating amyloid formation, in autoimmune diseases such as rheumatoid arthritis.

Osteostatin Inhibits Collagen-Induced Arthritis by Regulation of Immune Activation, Pro-Inflammatory Cytokines, and Osteoclastogenesis

In chronic inflammatory joint diseases, such as rheumatoid arthritis, there is an important bone loss. Parathyroid hormone-related protein (PTHrP) and related peptides have shown osteoinductive properties in bone regeneration models, but there are no data on inflammatory joint destruction. We have investigated whether the PTHrP (107-111) C-terminal peptide (osteostatin) could control the development of collagen-induced arthritis in mice. Administration of osteostatin (80 or 120 μg/kg s.c.) after the onset of disease decreased the severity of arthritis as well as cartilage and bone degradation. This peptide reduced serum IgG2a levels as well as T cell activation, with the downregulation of RORγt+CD4+ T cells and upregulation of FoxP3+CD8+ T cells in lymph nodes. The levels of key cytokines, such as interleukin(IL)-1β, IL-2, IL-6, IL-17, and tumor necrosis factor-α in mice paws were decreased by osteostatin treatment, whereas IL-10 was enhanced. Bone protection was related to reductions in receptor activator of nuclear factor-κB ligand, Dickkopf-related protein 1, and joint osteoclast area. Osteostatin improves arthritis and controls bone loss by inhibiting immune activation, pro-inflammatory cytokines, and osteoclastogenesis. Our results support the interest of osteostatin for the treatment of inflammatory joint conditions.

An HER2 DNA vaccine with evolution-selected amino acid substitutions reveals a fundamental principle for cancer vaccine formulation in HER2 transgenic mice

Enhancement of endogenous immunity to tumor-associated self-antigens and neoantigens is the goal of preventive vaccination. Toward this goal, we compared the efficacy of the following HER2 DNA vaccine constructs: vaccines encoding wild-type HER2, hybrid HER2 vaccines consisting of human HER2 and rat Neu, HER2 vaccines with single residue substitutions and a novel human HER2 DNA vaccine, ph(es)E2TM. ph(es)E2TM was designed to contain five evolution-selected substitutions: M198V, Q398R, F425L, H473R and A622T that occur frequently in 12 primate HER2 sequences. These ph(es)E2TM substitutions score 0 to 1 in blocks substitutions matrix (BLOSUM), indicating minimal biochemical alterations. h(es)E2TM recombinant protein is recognized by a panel of anti-HER2 mAbs, demonstrating the preservation of HER2 protein structure. Compared to native human HER2, electrovaccination of HER2 transgenic mice with ph(es)E2TM induced a threefold increase in HER2-binding antibody (Ab) and elevated levels of IFNγ-producing T cells. ph(es)E2TM, but not pE2TM immune serum, recognized HER2 peptide p95 ₃₅₅LPESFDGDPASNTAP₃₆₉, suggesting a broadening of epitope recognition induced by the minimally modified HER2 vaccine. ph(es)E2TM vaccination reduced tumor growth more effectively than wild-type HER2 or HER2 vaccines with more extensive modifications. The elevation of tumor immunity by ph(es)E2TM vaccination would create a favorable tumor microenvironment for neoantigen priming, further enhancing the protective immunity. The fundamental principle of exploiting evolution-selected amino acid substitutions is novel, effective and applicable to vaccine development in general.

Effect of methotrexate on collagen-induced arthritis in male Wistar rats

To evaluate the effect of methotrexate on collagen-induced arthritis, micro-computed tomography (micro-CT) and histopathological analyses were used in male Wistar rats. Rats were divided randomly into three groups. Group 1 was treated with 0.9% saline, and groups 2 and 3 were boosted with type Ⅱ collagen. From day 21 to 42, groups 1 and 2 were orally treated with 0.9% saline and group 3 was orally treated with 1.5 mg/kg methotrexate. All rats were sacrificed at day 42 after the first collagen treatment. Micro-CT analyses showed bony parameters, such as bone volume and trabecular number, were decreased in group 2 compared to group 1, and these parameters were recovered in group 3. Histopathological examination and pathological parameter scoring showed that the knee joints of rats in group 2 had severe joint destruction, showing cartilage and bone erosion, enlarged cavities with inflammatory cell infiltration and activation of synovial fibroblasts. By contrast, these changes were reduced in group 3. Taken together, methotrexate treatment showed therapeutic potential in male rat collagen-induced arthritis model, and micro-CT analysis and histopathological tools could be integrated to assess the quantification/qualification of arthritic lesions.

Effects of dioscin on T helper 17 and regulatory T-cell subsets in chicken collagen type II-induced arthritis mice

BACKGROUND

This study was conducted to investigate the treatment efficacies and immunological mechanisms of action of dioscin in mice with chicken collagen type II-induced arthritis (CIA).

METHODS

The CIA mice was randomly divided into the model group (M), dioscin group (D), and tripterygium group (T); a normal control group (C) was also included. Each group was orally administered with related drugs or an equal volume of solvent (group C) starting on the 21st day of primary immunity, after which the levels of T helper 17 cells (Th17), regulatory T cells (Tregs), and their related factors were detected on the 35th day.

RESULTS

Compared to group C, group M exhibited significantly increased levels of interleukin 17 (IL-17) and IL-6 and decreased IL-27 (p < 0.05). Group D exhibited significantly decreased levels of IL-17 and IL-6 compared with group M (p < 0.05). Group M showed a significantly increased ratio of Th17 cells (p < 0.05), while dioscin significantly reduced this ratio (p < 0.05). Groups M and C showed no significant difference in the ratio of Tregs (p > 0.05) but dioscin significantly increased this ratio (p < 0.05). Group M significantly increased signal transducer and activator of transcription 3 (STAT3) and STAT5 compared with that in group C (p < 0.05), while the T and D groups showed significantly reduced levels of STAT3 and STAT5 (p < 0.05).

CONCLUSION

Dioscin may affect the differentiation of Th17 and Tregs and secretion of related factors by regulating CD4 T cell subset-related signal transduction and the expression of transcription-activating factor STAT3 and STAT5, thus exerting useful immunoregulatory roles in CIA mice.

Experimental study of TNF-α receptor gene transfection by ultrasound-targeted microbubble destruction to treat collagen-induced arthritis in rats in vivo

Ultrasound-targeted microbubble destruction (UTMD) is a novel method for gene transfection. The aim of the present study was to identify the most suitable method of tumor necrosis factor (TNF)-α receptor (TNFR) gene transfection using UTMD for systemically treating a rat model of collagen-induced arthritis (CIA). Plasmids encoding the TNFR and enhanced green fluorescent protein (EGFP) with or without microbubbles were locally injected into the skeletal muscle and synovial membrane of CIA rats. The rats were divided into the following 6 groups: i) Group 1, plasmid + microbubble + ultrasound (muscle group); ii) group 2, plasmid + microbubble + ultrasound (joint group); iii) group 3, plasmid + ultrasound; iv) group 4, plasmid + microbubble; v) group 5, plasmid only and; vi) group 6, untreated controls. Rats were sacrificed at 2, 4 and 8 weeks of treatment. The transfection efficiency of the plasmids in the muscle or synovium was observed by fluorescence microscopy. Arthritis scores were calculated and serum levels of TNF-α were measured prior to and following treatment. Bilateral ankle joints were obtained and stained to observe synovial inflammation and the expression of TNF-α. EGFP expression was detected in all treated groups at each time point, and the fluorescence intensity of groups 1 and 2 was significantly greater than that of the other groups (P<0.05). For groups 1 and 2, the reductions in joint scores and serum levels of TNF-α were significant compared with the other groups (P<0.05). The number of synovial inflammatory cells and the synovial expression of TNF-α presented similar results among all experimental groups and no significant difference was observed between groups 1 and 2. Therefore, the results of the present study suggest that UTMD significantly enhanced the efficiency of TNFR gene transfection in the muscle and inflamed synovium of rats with. Regardless of whether the transfected TNFR gene was injected into the muscle or joint, it was continuously expressed in the rats for at least 8 weeks, which may improve arthritic symptoms and reduce the levels of inflammatory factors in the synovial tissues and peripheral blood.

Efficient Therapeutic Function and Mechanisms of Human Polyclonal CD8+CD103+Foxp3+ Regulatory T Cells on Collagen-Induced Arthritis in Mice

Objective

To investigate the potential therapeutic effect in a rheumatoid arthritis model of stable human CD8⁺ regulatory T cells (hCD8⁺Tregs) induced by TGF-β1 and rapamycin (RAPA) in vitro.

Methods

Human CD8⁺T cells were isolated from human peripheral blood mononuclear cells and induced/expanded with TGF-β1 and RAPA along with anti-CD3/28 beads and IL-2 in vitro and harvested as hCD8⁺Tregs. The phenotypes, suppressive characteristics, and stability of the hCD8⁺Tregs in an inflammatory microenvironment were examined in vitro. Human CD8⁺Tregs were transfused into an acollagen-induced arthritis (CIA) mouse model, and their therapeutic effects and related mechanisms were investigated.

Results

Human CD8⁺Tregs induced by TGF-β1/RAPA showed high expression of Foxp3 and CD103, exhibited vigorous suppression ability, and were stable in inflammatory microenvironments. In CIA mice, the clinical scores, levels of anti-collagen IgG antibody, and cartilage destruction were significantly reduced after adoptive transfusion with hCD8⁺Tregs. Moreover, hCD8⁺Treg treatment significantly reduced the number of Th17 cells, increased the number of CD4⁺IFN-γ⁺T cells, and produced self CD4⁺Foxp3⁺Tregs in vivo. In an in vitro cell coculture assay, hCD8⁺Tregs significantly inhibited mouse CD4⁺ effector T cell proliferation, induced mouse CD4⁺Foxp3⁺Treg and CD4⁺IFN-γ⁺Th1 cell production, reduced Th17 cell development, and downregulated CD80/86 expression on mature DCs (mDCs).

Conclusion

TGF-β1/RAPA can induce hCD8⁺Tregs with stable suppressive characteristics, which could significantly alleviate the severity of CIA based on their stable suppressive ability in an inflammatory microenvironment and further influence the function of other downstream cell subtypes. Human CD8⁺Tregs might be a therapeutic strategy for rheumatoid arthritis.

An Overview of VPAC Receptors in Rheumatoid Arthritis: Biological Role and Clinical Significance

The axis comprised by the Vasoactive Intestinal Peptide (VIP) and its G protein-coupled receptors (GPCRs), VPAC1, and VPAC2, belong to the B1 family and signal through Gs or Gq proteins. VPAC receptors seem to preferentially interact with Gs in inflammatory cells, rather than Gq, thereby stimulating adenylate cyclase activity. cAMP is able to trigger various downstream pathways, mainly the canonical PKA pathway and the non-canonical cAMP-activated guanine nucleotide exchange factor (EPAC) pathway. Classically, the presence of VPACs has been confined to the plasma membrane; however, VPAC1 location has been described in the nuclear membrane in several cell types such as activated Th cells, where they are also functional. VPAC receptor signaling modulates a number of biological processes by tipping the balance of inflammatory mediators in macrophages and other innate immune cells, modifying the expression of TLRs, and inhibiting MMPs and the expression of adhesion molecules. Receptor signaling also downregulates coagulation factors and acute-phase proteins, promotes Th2 over Th1, stimulates Treg abundance, and finally inhibits a pathogenic Th17 profile. Thus, the VIP axis signaling regulates both the innate and adaptive immune responses in several inflammatory/autoimmune diseases. Rheumatoid arthritis (RA) is a complex autoimmune disease that develops on a substrate of genetically susceptible individuals and under the influence of environmental factors, as well as epigenetic mechanisms. It is a heterogeneous disease with different pathogenic mechanisms and variable clinical forms between patients with the same diagnosis. The knowledge of VIP signaling generated in both animal models and human ex vivo studies can potentially be translated to clinical reality. Most recently, the beneficial effects of nanoparticles of VIP self-associated with sterically stabilized micelles have been reported in a murine model of RA. Another novel research area is beginning to define the receptors as biomarkers in RA, with their expression levels shown to be associated with the activity of the disease and patients-reported impairment. Therefore, VPAC expression together VIP genetic variants could allow patients to be stratified at the beginning of the disease with the purpose of guiding personalized treatment decisions.

The effect of the cholinergic anti-inflammatory pathway on collagen-induced arthritis involves the modulation of dendritic cell differentiation

BACKGROUND

The cholinergic anti-inflammatory pathway (CAP) has a strong anti-inflammatory effect on collagen-induced arthritis (CIA), a classic animal model of rheumatoid arthritis (RA). However, the underlying immune regulatory mechanism remains unclear. Here, we investigated the effect of the CAP on arthritis development and the involvement of dendritic cells (DCs).

METHODS

Forty DBA/1 mice were randomly divided into five groups: a control group (sham vagotomy+ phosphate-buffered saline; shamVGX+PBS), a CIA group (shamVGX+CIA + PBS), a vagotomy group (VGX + CIA + PBS), a GTS-21 (4 mg/kg) group (shamVGX+CIA + GTS-4), and a GTS-21 (8 mg/kg) group (shamVGX+CIA + GTS-8). The vagotomy group underwent left cervical vagotomy 4 days before arthritis induction, whereas the sham-vagotomy group underwent vagus nerve exposure. Mice were pretreated with GTS-21 by intraperitoneal injection on the day of surgery. The degree of arthritis was measured by using the arthritis score, hematoxylin and eosin staining, and TRAP (tartrate-resistant acid phosphatase) staining. Flow cytometry was used to detect the expression of CD80 and major histocompatibility complex II (MHC II) on CD11c⁺ DCs in the spleen. Luminex was used to detect the serum concentration of interleukin-6 (IL-6), tumor necrosis factor-alpha (TNFα), and IL-10. Immunohistochemistry was used to detect CD11c expression in the synovium. The effects of GTS-21 on DC differentiation and maturation were examined in vitro by treating bone marrow-derived DCs with GTS-21 and assessing differentiation and maturation. Flow cytometry was used to analyze CD80 and MHC II expression on the surface of DCs.

RESULTS

GTS-21 treatment ameliorated clinical arthritis in a mouse model of CIA in vivo, decreasing the secretion of pro-inflammatory cytokines in the serum and downregulating CD80 and MHC II expression on DCs in the spleen of CIA mice. GTS-21 treatment strongly suppressed the infiltration of DCs into the synovium. Vagotomy itself did not exacerbate the severity of arthritis in CIA mice. In vitro, GTS-21 (10 μmol/L) significantly downregulated CD80 and MHC II in bone marrow-derived immature DCs and this effect was blocked by the α7-nicotinic acetylcholine receptor antagonist methyllycaconitine (MLA). However, GTS-21 had no effects on mature DCs.

CONCLUSIONS

The present study provides new insight into the mechanism underlying the effects of the CAP on RA and indicates that the immunosuppressive effect of GTS-21 may be mediated by the inhibition of DC differentiation.

Jatrorrhizine Hydrochloride Suppresses Proliferation, Migration, and Secretion of Synoviocytes In Vitro and Ameliorates Rat Models of Rheumatoid Arthritis In Vivo

Jatrorrhizine hydrochloride (JH), an active component isolated from the traditional Chinese herb Coptis chinensis, has been reported to have antimicrobial, antitumor, antihypercholesterolemic, and neuroprotective activities. However, its antirheumatoid arthritis (RA) property remains unknown. In this study, a collagen-induced arthritis (CIA) rat model was used to evaluate the therapeutic effects of JH on RA by using arthritis score, radiological evaluation, and histopathological assessment. The in vitro effects of JH on proliferation, migration, and production of inflammatory mediators in RA-derived fibroblast-like synoviocyte MH7A cells were determined by the EdU incorporation assay, wound healing assay, real-time PCR, and ELISA, respectively. The in vivo studies showed that JH treatment significantly prevented the progression and development of RA in CIA rats through anti-inflammation and suppressing bone destruction. The in vitro studies revealed that JH could effectively attenuate the destructive phenotypes of MH7A cells, including inhibiting proliferation, migration, and production of inflammatory mediators. Further mechanistic analysis demonstrated that JH suppressed tumor necrosis factor alpha (TNFα)-stimulated activations of nuclear factor of kappaB (NF-κB) and mitogen-activated protein kinases (MAPKs) (ERK and p38) leading to the downregulation of proinflammatory cytokines, which might be beneficial to the antiproliferative and antimigratory activities of FLS cells. Collectively, our results demonstrated that JH has a great potential to be developed into a novel therapeutic agent for treating RA.

Physcion 8‑O‑β‑glucopyranoside extracted from Polygonum cuspidatum exhibits anti‑proliferative and anti‑inflammatory effects on MH7A rheumatoid arthritis‑derived fibroblast‑like synoviocytes through the TGF‑β/MAPK pathway

The present study aimed to investigate the anti-arthritic effect of physcion 8-O-β-glucopyranoside (POGD) and its possible mechanisms. The anti-proliferative effects of POGD on MH7A cells were detected using a CCK-8 assay, and the release of pro-inflammatory cytokines, interleukin (IL)-1β, IL-6, IL-8, IL-12 and IL-17A, were determined by ELISA. A type II collagen-induced arthritis (CIA) rat model was established to evaluate the anti-arthritic effect of POGD in vivo. The paw volumes, arthritis indices and serum levels of tumor necrosis factor (TNF)-α, IL-1β, IL-6, IL-8, IL-17A were determined by ELISA. The mRNA expression levels of matrix metalloproteinase (MMP)-2, MMP-3, MMP-9, vascular endothelial growth factor and cyclooxygenase-2 were determined by reverse transcription-quantitative polymerase chain reaction analysis, and the expression levels of transforming growth factor (TGF)-β1, small mothers against decapentaplegic (Smad)4, Smad7, c-Jun N-terminal kinase (JNK), phosphorylated (p-)JNK, p-P38, P38, p-extracellular signal-regulated kinase (ERK)1/2, ERK1/2, nuclear factor (NF)-κB p65 in the nucleus (N), cytosolic NF-κB p65 (C), and inhibitor of NF-κB (IκB) were determined by western blot analysis. The results indicated that POGD significantly inhibited MH7A cell growth. POGD markedly inhibited paw swelling and the arthritis indices of the CIA rats, and POGD may also inhibit the release of pro-inflammatory cytokines. Furthermore, POGD downregulated the expression levels of TGF-β1, Smad4, NF-κB p65 (N), p38, p-p38, p-ERK1/2, JNK, p-JNK, TGF-β1, Smad4, p-JNK, JNK, p-P38, P38, p-ERK1/2, ERK1/2 and NF-κB p65 (N), and upregulated the Smad7, NF-κB p65 (C) and IκB in TNF-α induced MH7A cells. In conclusion, the results suggested that POGD is a promising potential anti-inflammatory drug, and that POGD may decrease the expression of pro-inflammatory cytokines and mediators via inhibiting the TGF-β/NF-κB/mitogen-activated protein kinase pathways.

The role of Syk in peripheral T cells

The aim of this study was to understand how Syk affects peripheral T cell function. T cells from Syk^-/- chimeric mice and DR1 Syk^fl/fl CD4^cre conditional mice gave strong CD3-induced Th1, Th2, and Th17 cytokine responses. However, an altered peptide ligand (APL) of human CII (256-276) with two substitutions (F263N, E266D), also called A12, elicited only Th2 cytokine responses from Syk^fl/fl T cells but not Syk^fl/fl-CD4^cre T cells. Western blots revealed a marked increase in the phosphorylation of Syk, JNK and p38 upon A12/DR1 activation in WT or Syk^fl/fl T cells but not in Syk^fl/flCD4^-cre cells. We demonstrate that Syk is required for the APL- induction of suppressive cytokines. Chemical Syk inhibitors blocked activation of GATA-3 by peptide A12/DR1. In conclusion, this study provides novel insights into the role that Syk plays in directing T cell activity, and may shape therapeutic approaches for autoimmune diseases.

Heterologous human/rat HER2-specific exosome-targeted T cell vaccine stimulates potent humoral and CTL responses leading to enhanced circumvention of HER2 tolerance in double transgenic HLA-A2/HER2 mice

DNA vaccines composed of heterologous human HER2 and rat neu sequences induce stronger antibody response and protective antitumor immunity than either HER2 or neu DNA vaccines in transgenic mice. We previously developed HER2-specific exosome-targeted T-cell vaccine HER2-T_EXO capable of stimulating HER2-specific CD8⁺ T-cell responses, but only leading to partial protective immunity in double-transgenic HLA-A2/HER2 mice with self-immune tolerance to HER2. Here, we constructed an adenoviral vector AdV_HuRt expressing HuRt fusion protein composed of NH₂-HER2_1-407 (Hu) and COOH-neu_408-690 (Rt) fragments, and developed a heterologous human/rat HER2-specific exosome-targeted T-cell vaccine HuRt-T_EXO using polyclonal CD4⁺ T-cells uptaking exosomes released by AdV_HuRt-transfected dendritic cells. We found that the HuRt-T_EXO vaccine stimulates enhanced CD4⁺ T-cell responses leading to increased induction of HER2-specific antibody (∼70 µg/ml) compared to that (∼40 µg/ml) triggered by the homologous HER2-T_EXO vaccine. By using PE-H-2K^d/HER2_23-71 tetramer, we determined that HuRt-T_EXO stimulates stronger HER2-specific CD8⁺ T-cell responses eradicating 90% of HER2-specific target cells, while HER2-T_EXO-induced CD8⁺ T-cell responses only eliminating 53% targets. Furthermore, HuRt-T_EXO, but not HER2-T_EXO vaccination, is capable of suppressing early stage-established HER2-expressing 4T1_HER2 breast cancer in its lung metastasis or subcutaneous form in BALB/c mice, and of completely protecting transgenic HLA-A2/HER2 mice from growth of HLA-A2/HER2-expressing BL6-10_A2/HER2 melanoma. HuRt-T_EXO-stimulated HER2-specific CD8⁺ T-cells not only are cytolytic to trastuzumab-resistant HLA-A2/HER2-expressing BT474/A2 breast tumor cells in vitro but also eradicates pre-established BT474/A2 tumors in athymic nude mice. Therefore, our novel heterologous human/rat HER2-specific T-cell vaccine HuRt-T_EXO, circumventing HER2 tolerance, may provide a new therapeutic alternative for patients with trastuzumab-resistant HER2⁺ breast tumor.

Therapeutic effects of isothiocyanate prodrugs on rheumatoid arthritis

Isothiocyanates 7a and 7b have poor stability and aqueous solubility. To address these problems, prodrugs 8a and 8b were synthesized. Prodrugs 8a and 8b were stable in HEPES buffer at pH 4.4, but released the active compounds 7a and 7b in HEPES buffer at pH 7.4 and in mouse plasma, respectively. Compound 8a and especially compound 8b showed anti-inflammatory effects. Compound 8b demonstrated significant efficacy in animal models of traumatic inflammation, acute inflammation and rheumatoid arthritis. Compound 8b also did not cause appreciable toxicity in mice after 5 weeks at a daily dose of 200 mg/kg.

In Vivo Studies on the Influence of Bacteriophage Preparations on the Autoimmune Inflammatory Process

Phage preparations used for phage therapy may have not only direct antibacterial action but also immunomodulating effects mediated by phages themselves as well as by bacterial antigens. Therefore phage application in patients with immune disorders, and especially with autoimmune diseases, requires special attention. The aim of this study was to investigate the effect of phage lysates (staphylococcal phages A3/R, phi200, and MS-1 cocktail, enterococcal phage 15/P, Pseudomonas phage 119x, and E. coli T4 phage) as well as purified T4 phage on the course of murine collagen-induced arthritis (CIA), commonly used as an animal model of rheumatoid arthritis. Intraperitoneal application of phage lysates or purified T4 phage did not aggravate the course of autoimmune joint disease. Moreover, although endotoxins are known to potentiate CIA, the systemic administration of phage lysate of Pseudomonas aeruginosa, which contains debris of this Gram-negative bacillus, did not significantly influence CIA although the sonicate of the corresponding bacterial strain did. Interestingly, a purified T4 phage revealed some anti-inflammatory activity when applied under the therapeutic scheme. Our preliminary results do not suggest that phages may aggravate the symptoms of rheumatoid arthritis. In contrast T4 phage may even exert an immunosuppressive effect.

Complete overview of protein-inactivating sequence variations in 36 sequenced mouse inbred strains

Mouse inbred strains remain essential in science. We have analyzed the publicly available genome sequences of 36 popular inbred strains and provide lists for each strain of protein-coding genes that acquired sequence variations that cause premature STOP codons, loss of STOP codons and single nucleotide polymorphisms, and short in-frame insertions and deletions. Our data give an overview of predicted defective proteins, including predicted impact scores, of all these strains compared with the reference mouse genome of C57BL/6J. These data can also be retrieved via a searchable website (mousepost.be) and allow a global, better interpretation of genetic background effects and a source of naturally defective alleles in these 36 sequenced classical and high-priority mouse inbred strains.

Effects of polysaccharide fractions isolated from Caltha palustris L. on the activity of phagocytic cells & humoral immune response in mice with collagen-induced arthritis: A comparison with methotrexate

BACKGROUND & OBJECTIVES

The extracts from Caltha palustris L. have been shown to be beneficial for treating arthritis and rheumatism. In this study, the immunomodulatory effects of polysaccharide fractions B and C of C. palustris extracts were studied, using the collagen-induced arthritis (CIA) mouse arthritis experimental model. The aim was to determine the activity of blood phagocytic cells and humoral immune response in CIA mice treated with polysaccharide fractions from C. palustris.

METHODS

The effects of fractions B and C of C. palustris were explored by evaluating phagocytic activity of peripheral blood granulocytes and monocytes and humoral immune response in sheep red blood cell (SRBC)-immunized mice. The results were compared with methotrexate (MTX) treatment. Following the onset of CIA, DBA/1J mice were treated for 21 days with B or C fractions (10 mg/kg; i.p.) or MTX (every 48 h, 6.6 mg/kg; i.p.).

RESULTS

The results showed that fraction B reduced the level of interleukin (IL)-1β, boosted nitric oxide synthesis in murine peritoneal macrophages stimulated in vitro with lipopolysaccharide and enhanced the monocyte phagocytic activity. Exposure of SRBC-immunized mice to fraction B and MTX during the course of CIA resulted in decreased total anti-SRBC haemagglutinin titres.

INTERPRETATION & CONCLUSIONS

Fraction B of C. palustris polysaccharides modulated macrophage function and exerted beneficial effects on the clinical course of CIA in mice. The results also suggested efficacy of fraction B was comparable to that of MTX treatment for certain parameters.

Ethyl Caffeate Ameliorates Collagen-Induced Arthritis by Suppressing Th1 Immune Response

The present study was designed to assess the antiarthritic potential of ECF in collagen-induced arthritis (CIA) and explore its underlying mechanism. Methods. In vitro, lymphocyte proliferation assay was measured by CCK-8 kit. In vivo, the therapeutic potential of ECF on CIA was investigated; surface marker, Treg cell, and intracellular cytokines (IL-17A and IFN-γ) were detected by flow cytometry. Th1 cell differentiation assay was performed, and mRNA expression in interferon-γ-related signaling was examined by q-PCR analysis. Results. In vitro, ECF markedly inhibited the proliferation of splenocytes in response to ConA and anti-CD3. In vivo, ECF treatment reduced the severity of CIA, inhibited IFN-γ and IL-6 secretion, and decreased the proportion of CD11b+Gr-1+ splenic neutrophil. Meanwhile, ECF treatment significantly inhibited the IFN-γ expression in CD4+T cell without obviously influencing the development of Th17 cells and T regulatory cells. In vitro, ECF suppressed the differentiation of naive CD4+ T cells into Th1. Furthermore, ECF intensely blocked the transcriptional expression in interferon-γ-related signaling, including IFN-γ, T-bet, STAT1, and STAT4. Conclusion. Our results indicated that ECF exerted antiarthritic potential in collagen-induced arthritis by suppressing Th1 immune response and interferon-γ-related signaling.

Fibroblast-like synoviocyte metabolism in the pathogenesis of rheumatoid arthritis

An increasing number of studies show how changes in intracellular metabolic pathways alter tumor and immune cell function. However, little information about metabolic changes in other cell types, including synovial fibroblasts, is available. In rheumatoid arthritis (RA), fibroblast-like synoviocytes (FLS) are the most common cell type at the pannus–cartilage junction and contribute to joint destruction through their production of cytokines, chemokines, and matrix-degrading molecules and by migrating and invading joint cartilage. In this review, we show that these cells differ from healthy synovial fibroblasts, not only in their marker expression, proto-oncogene expression, or their epigenetic changes, but also in their intracellular metabolism. These metabolic changes must occur due to the stressful microenvironment of inflamed tissues, where concentrations of crucial nutrients such as glucose, glutamine, and oxygen are spatially and temporally heterogeneous. In addition, these metabolic changes will increase metabolite exchange between fibroblast and other synovial cells, which can potentially be activated. Glucose and phospholipid metabolism as well as bioactive lipids, including sphingosine-1-phosphate and lysophosphatidic acid, among others, are involved in FLS activation. These metabolic changes likely contribute to FLS involvement in aspects of immune response initiation or abnormal immune responses and strongly contribute to joint destruction.

Photobiomodulation therapy associated with treadmill training in the oxidative stress in a collagen-induced arthritis model

Rheumatoid arthritis (RA) is a chronic inflammatory disease characterized by chronic and systemic inflammation, which leads to the destruction of the cartilage and bone and affects tissues in multiple joints. Oxidative stress has been implicated with regards to involvement in various disease conditions, such as diabetes mellitus and neurodegenerative, respiratory, cardiovascular, and RA diseases. In vivo experimental studies using photobiomodulation therapy (PBMT) have shown positive effects in reducing lipid peroxidation and in increasing antioxidant activity. The regular practice of physical exercise has also been reported to be a beneficial treatment capable of reducing oxidative damage. Thus, the aim of this study was to analyze the effects of photobiomodulation therapy at 2- and 4-J doses associated with physical exercise on oxidative stress in an experimental model of RA in protein expression involving superoxide dismutase (SOD), glutathione peroxidase (GPX), and/or catalase (CAT) on thiobarbituric acid reactive substances (TBARS). In this study, 24 male Wistar rats divided into four groups were submitted to an RA model (i.e., collagen-induced arthritis, CIA), with the first immunization performed at the base of the tail on days 0 and 7 were included. After 28 days, a third intraarticular dose was administered in both knees of the animals. After the last induction, PBMT was started immediately, transcutaneously at two points (i.e., the medial and lateral), with a total of 15 applications. Treadmill exercise was also started the day after the last induction, and lasted for 5 weeks. With respect to results, we obtained the decreases in the lipid peroxidation and the increases of the antioxidant activities of SOD, GPX and CAT, with physical exercise associated to PBMT in doses of 2 and 4 J. In conclusion, physical exercise associated with PBMT decreases lipid peroxidation and increases antioxidant activity.

FGF21 exerts comparable pharmacological efficacy with Adalimumab in ameliorating collagen-induced rheumatoid arthritis by regulating systematic inflammatory response

Previous studies have reported that Fibroblast growth factor 21 (FGF21) can regulate inflammation and may play an important role in inflammatory and immune-mediated diseases, such as autoimmune diseases. Adalimumab is one of the clinically effective anti-rheumatoid arthritis (RA) drugs. The aim of this study was to compare the therapeutic efficacy of FGF21 and Adalimumab on collagen-induced arthritis (CIA) model mice. Mice with CIA were subcutaneously treated with FGF21 or Adalimumab at dose of 1mgkg^-1d^-1, respectively. Our results showed that FGF21 significantly alleviated the severity of arthritis by reducing cellular immune responses and exerted the similar anti-inflammatory effects with Adalimumab in decreasing the mRNA and protein expression levels of IL-2, IL-6 and IL-17. However, the expression levels of IL-1β, RANKL and IL-10 in the mice treated with FGF21 were decreased 2.2-fold, 2.5-fold and increased 4.3-fold compared with Adalimumab, respectively. However, the levels of TNF-α in the mice treated with Adalimumab were lower than those in the mice treated with FGF21. Western blotting results demonstrated that FGF21 displayed equivalent effects with Adalimumab by inhibiting NF-κB/IκBα signaling pathway. However, FGF21 could also regulate systematic inflammatory response and the mechanism maybe related to other signal pathway. In summary, FGF21 exerts comparable pharmacological efficacy with Adalimumab by regulating systematic inflammatory response, providing that FGF21 may be a promising therapeutic agent for RA patients.

Effects of the stem extracts of Schisandra glaucescens Diels on collagen-induced arthritis in Balb/c mice

ETHNOPHARMACOLOGICAL RELEVANCE

Schisandra glaucescens Diels (SGD) is used in a subclass of traditional Chinese medicine known as "Tujia drugs". It has been long used for the treatment of rheumatoid arthritis (RA), cough with dyspnea, spontaneous sweating, night sweating, chronic diarrhea, and neurasthenia. As a woody liana growing in mountain jungles at the altitudes of 750-1800m, it is mainly distributed in Sichuan and Hubei Provinces of China.

AIM OF THE STUDY

To evaluate the antiarthritic activity of acetate (EA) and n-butanol (Bu) fractions of SGD extract on a collagen-induced arthritis mice model.

MATERIALS AND METHODS

Acute toxicity of EA and Bu fractions of SGD extract was evaluated by gavage on normal mice. Pharmacological investigations were conducted on arthritis male Balb/c mice. The animal model was induced by immunization with type II bovine collagen (CII) on the 1st and the 14th day of the experimental schedule. EA fraction (104, 312, 936mg/kg), Bu fraction (156, 469, 1407mg/kg) of SGD extract was orally administered every two days since the 15th day for 3 weeks. Progression of edema in the paws was measured using a vernier caliper every 3 days since the 10th day. At the end of the experiment, the spleen index and histological changes of the hind knee joints were investigated. Additionally, to explore the possible antirheumatic mechanisms of the EA and Bu fractions, ELISA was carried out to analyze TNF-α, IL-10, IL-6 and IL-1β in the serum.

RESULTS

The half lethal doses of both EA and Bu fractions were much higher than the dose administered in the pharmacological investigations. Oral administration of EA fraction and Bu fraction of SGD extract significantly and does-dependently inhibited type ІІ collagen induced arthritis (CIA) in mice, as indicated by the effects on paws swelling and spleen index. Histopathological examinations demonstrated that SGD effectively protected the bones and cartilages of knee joints from erosion, lesion and deformation. Besides, the serum concentrations of cytokines TNF-α, IL-1β and IL-6 were significantly lower than the ones from the vehicle control group. Respectively, while cytokine IL-10 was remarkably higher compare with the vehicle control group.

CONCLUSIONS

SGD might be a safe and effective candidate for the treatment of RA, and deserves further investigation on the chemical components in both EA and Bu fractions of SGD extract.

Characterization of the Syk-Dependent T Cell Signaling Response to an Altered Peptide

Rheumatoid arthritis is an autoimmune disorder characterized by T cell dysregulation. We have shown that an altered peptide ligand (A9) activates T cells to use an alternate signaling pathway that is dependent on FcRγ and spleen tyrosine kinase, resulting in downregulation of inflammation. In the experiments described in this study, we have attempted to determine the molecular basis of this paradox. Three major Src family kinases found in T cells (Lck, Fyn, and Lyn) were tested for activation following stimulation by A9/I-A^q Unexpectedly we found they are not required for T cell functions induced by A9/I-A^q, nor are they required for APL stimulation of cytokines. On the other hand, the induction of the second messenger inositol trisphosphate and the mobilization of calcium are clearly triggered by the APL A9/I-A^q stimulation and are required for cytokine production, albeit the cytokines induced are different from those produced after activation of the canonical pathway. DBA/1 mice doubly deficient in IL-4 and IL-10 were used to confirm that these two cytokines are important for the APL-induced attenuation of arthritis. These studies provide a basis for exploring the effectiveness of analog peptides and the inhibitory T cells they induce as therapeutic tools for autoimmune arthritis.

Anti-rheumatoid arthritic effects of Saussurea involucrata on type II collagen-induced arthritis in rats

Saussurea involucrata (SI) has long been used under the herbal name "snow lotus" for treatment of inflammation and pain-related diseases in traditional Chinese medicine. The present study aimed to evaluate the pharmacological effects of SI on collagen II (CII)-induced arthritis in rats. Rats with collagen II (CII)-induced arthritis were orally administered SI (420 mg kg(-1)) for 40 consecutive days. Histopathological examination indicated that SI alleviates infiltration of inflammatory cells and synovial hyperplasia and slows joint destruction. SI intervention reduced the serum levels of RF, COMP, CRP and anti-CII IgG. Results also showed that SI is a potential therapeutic agent for alleviating the severity of the disease based on the reduced arthritic index. It was concluded that SI can ameliorate inflammation and joint destruction in CIA rats.

Anti-arthritogenic and cardioprotective action of hesperidin and daidzein in collagen-induced rheumatoid arthritis

Atherosclerosis has been linked to chronic inflammatory processes. Changes in the levels of lipoproteins, especially low-density lipoprotein or its variants, as well as inflammatory markers are risk factors for the atherosclerosis. In the present study, an experimental model of rheumatoid arthritis was developed by administrating collagen suspension intradermally in the tail region of Wistar albino rats. At the same time, a suspension of hesperidin (50 mg/kg body weight) and daidzein (20 mg/kg body weight) was orally administrated. The compounds were given in the morning and evening for 21 days. Levels of inflammatory markers in the homogenate of knee joints of experimental rats as well as plasma lipoproteins were investigated. The administration of hesperidin and daidzein caused significant (p < 0.001) decrease in articular elastase activity, TNF-α, and malondialdehyde levels. Further, arthritis scoring and histological findings supported the anti-inflammatory actions of the test compounds. Interestingly, the test compounds also lowered the plasma low-density lipoprotein cholesterol, very low-density lipoprotein cholesterol, and triglyceride but increased the level of high-density lipoprotein cholesterol. The test compounds thus ameliorated the risk factors of atherosclerosis. Furthermore, antioxidant roles of hesperidin as well as daidzein were evident from decrease in free radical load demonstrated as increase in total antioxidant level in plasma of arthritic animals treated with hesperidin and daidzein. In a separate in vitro experiment, enhanced free radical scavenging activity of hesperidin was demonstrated against 2,2-diphenyl-1-picrylhydrazyl and 2,2-azinobis-3-ethylbenzothiazoline-6-sulfonic acid. The anti-inflammatory, hypolipidemic, and antioxidant actions of the naturally occurring test compounds, particularly hesperidin, seem to be quite effective against rheumatoid arthritis and atherosclerosis. Thus, their consumption may be helpful in prevention or at least delaying the onset of these diseases in susceptible individuals.

PD-1/PD-L and autoimmunity: A growing relationship

Programmed death 1 (PD-1) and its ligands, namely PD-L1 and PD-L2, are one of the key factors responsible for inhibitory T cell signaling, mediating the mechanisms of tolerance and providing immune homeostasis. Mounting evidence demonstrates that impaired PD-1:PD-L function plays an important role in a variety of autoimmune diseases such as Type 1 diabetes (T1D), encephalomyelitis, inflammatory bowel diseases (IBD), Rheumatoid Arthritis (RA), autoimmune hepatitis (AIH), Behcet's disease (BD), myasthenia gravis (MG), autoimmune uveitis (AU), Sjögren's syndrome (SjS), systemic lupus erythematosus (SLE), systemic sclerosis (SSc), myocarditis, and ankylosing spondylitis (AS). By investigating the candidate genes, genome-wide association studies, and identification of single nucleotide polymorphisms (SNPs) in PD-1 gene in humans, it has been shown that there is a higher risk in relevant genetic associations with developing autoimmune diseases in certain ethnic groups. In this review we have tried to present a comprehensive role of PD-1:PD-L in all recently studied autoimmune diseases.