The role of interleukin-17 in mediating joint destruction in rheumatoid arthritis

Interactions Between HDL and CD4+ T Cells: A Novel Understanding of HDL Anti-Inflammatory Properties

Several studies in animal models and human cohorts have recently suggested that HDLs (high-density lipoproteins) not only modulate innate immune responses but also adaptative immune responses, particularly CD4+ T cells. CD4+ T cells are central effectors and regulators of the adaptive immune system, and any alterations in their homeostasis contribute to the pathogenesis of cardiovascular diseases, autoimmunity, and inflammatory diseases. In this review, we focus on how HDLs and their components affect CD4+ T-cell homeostasis by modulating cholesterol efflux, immune synapsis, proliferation, differentiation, oxidative stress, and apoptosis. While the effects of apoB-containing lipoproteins on T cells have been relatively well established, this review focuses specifically on new connections between HDL and CD4+ T cells. We present a model where HDL may modulate T cells through both direct and indirect mechanisms.

Secukinumab for children and adolescents with enthesitis-related arthritis and psoriatic arthritis: lessons from treatment in adults and the way forward

INTRODUCTION

Targeting IL-17A using Secukinumab, a humanized monoclonal immunoglobulin G1 (IgG1)/κ against IL-17A is a therapeutic option for immune-mediated disorders such as psoriasis and ankylosing spondylitis. The US Food and Drug Administration and the European Medicines Agency have approved it for the treatment of moderate to severe plaque psoriasis, active psoriatic arthritis, ankylosing spondylitis, and non-radiographic axial spondylarthritis. Recently it has also been approved for use in children with severe plaque psoriasis, active psoriatic arthritis, and enthesitis-related arthritis.

AREAS COVERED

This review focuses on the role of Secukinumab in the management of children and adolescents with enthesitis-related arthritis and psoriatic arthritis. We discuss the salient findings of pivotal RCTs and other studies supporting the use of Secukinumab in adults and children, in particular, focusing on its safety and efficacy.

EXPERT OPINION

Secukinumab is a therapeutic target for psoriasis, psoriatic arthritis, and spondyloarthropathies in both adults and children. No major safety signals are observed with its use in short-term follow-up. Thus far, Secukinumab has not been found to significantly increase the risk of tuberculosis (TB).

The regulatory mechanism and potential application of IL-23 in autoimmune diseases

IL-23 is a heterodimeric pro-inflammatory cytokine secreted by dendritic cells and macrophages that belongs to the IL-12 family. It has pro-inflammatory effects and is a key cytokine and upstream regulatory cytokine involved in protective immune responses, stimulating the differentiation and proliferation of downstream effectors such as Th17 cells. It is expressed in various autoimmune diseases such as psoriasis, systemic lupus erythematosus (SLE), rheumatoid arthritis (RA). The IL-23/TH17 axis formed by IL-23 and TH17 has been confirmed to participate in autoimmune diseases pathogenesis. IL-23R is the receptor for IL-23 and plays an activating role. Targeting IL-23 is currently the main strategy for the treatment of various autoimmune diseases. In this review we summarized the mechanism of action and clinical application potential of IL-23 in autoimmune diseases by summarizing the latest research results and reviewing the literature, which would help to further understand IL-23 and provide a theoretical basis for future clinical targeting and drug development.

Galectin-9 expression correlates with therapeutic effect in rheumatoid arthritis

Galectin-9 (Gal-9) is a multifunctional immunomodulatory factor highly expressed in RA. This study aimed to investigate the expression of Gal-9 and its correlation with disease activity and therapeutic response in RA patients. Active RA patients were enrolled and treated with tacrolimus (TAC) alone or in combination therapy for 12 weeks in a prospective cohort study. Clinical and immunological parameters were recorded at baseline and week 12. We measured Gal-9 expression in different T cell subsets and in plasma. The disease activity of RA patients decreased after treatment. At baseline, the Gal-9 expression percentage was higher in the group with severe disease than in mild or moderate groups. After treatment, the Gal-9 expression in CD3⁺, CD4⁺, CD8⁺ and CD4^-CD8⁻ cell subsets decreased, as well as Gal-9 mean fluorescence intensity in CD3⁺, CD4⁺ and CD8⁺ T cells. Similarly, plasma Gal-9 levels were lower at week 12 than at baseline. Good responders showed significantly lower Gal-9 expression on CD3⁺ and CD4⁺ T cell subsets and lower plasma Gal-9 levels than poor responders. Gal-9 expression positively correlates with disease activity in RA patients. Gal-9 can be regarded as a new biomarker for evaluating RA activity and therapeutic effect, including TAC.

Metformin: A Potential Therapeutic Tool for Rheumatologists

Metformin is an oral antihyperglycemic drug widely used to treat type 2 diabetes, acting via indirect activation of 5′ Adenosine Monophosphate-activated Protein Kinase (AMPK). Actually, evidence has accumulated of an intriguing anti-inflammatory activity, mainly mediated by AMPK through a variety of mechanisms such as the inhibition of cytokine-stimulated Nuclear Factor-κB (NF-κB) and the downregulation of the Janus Kinase/Signal Transducer and Activator of Transcription (JAK/STAT) signaling pathways. Moreover, AMPK plays an important role in the modulation of T lymphocytes and other pivotal cells of the innate immune system. The current understanding of these AMPK effects provides a strong rationale for metformin repurposing in the management of autoimmune and inflammatory conditions. Several studies demonstrated metformin’s beneficial effects on both animal and human rheumatologic diseases, especially on rheumatoid arthritis. Unfortunately, even though data are large and remarkable, they almost exclusively come from experimental investigations with only a few from clinical trials. The lack of support from prospective placebo-controlled trials does not allow metformin to enter the therapeutic repertoire of rheumatologists. However, a large proportion of rheumatologic patients can currently benefit from metformin, such as those with concomitant obesity and type 2 diabetes, two conditions strongly associated with rheumatoid arthritis, osteoarthritis, and gout, as well as those with diabetes secondary to steroid therapy.

Nanomedicines for the delivery of glucocorticoids and nucleic acids as potential alternatives in the treatment of rheumatoid arthritis

Rheumatoid arthritis (RA) is a chronic autoimmune disease that affects 0.5-1% of the world population. Current treatments include on one hand non-steroidal anti-inflammatory drugs and glucocorticoids (GCs) for treating pain and on the other hand disease-modifying anti-rheumatic drugs such as methotrexate, Janus kinase inhibitors or biologics such as antibodies targeting mainly cytokine expression. More recently, nucleic acids such as siRNA, miRNA, or anti-miRNA have shown strong potentialities for the treatment of RA. This review discusses the way nanomedicines can target GCs and nucleic acids to inflammatory sites, increase drug penetration within inflammatory cells, achieve better subcellular distribution and finally protect drugs against degradation. For GCs such a targeting effect would allow the treatment to be more effective at lower doses and to reduce the administration frequency as well as to induce much fewer side-effects. In the case of nucleic acids, particularly siRNA, knocking down proteins involved in RA, could importantly be facilitated using nanomedicines. Finally, the combination of both siRNA and GCs in the same carrier allowed for the same cell to target both the GCs receptor as well as any other signaling pathway involved in RA. Nanomedicines appear to be very promising for the delivery of conventional and novel drugs in RA therapeutics. This article is categorized under: Therapeutic Approaches and Drug Discovery > Emerging Technologies Biology-Inspired Nanomaterials > Nucleic Acid-Based Structures.

Role of Chemokines and Chemokine Receptors in Rheumatoid Arthritis

Rheumatoid arthritis (RA) is one of the most prevalent autoimmune diseases and a prototypic inflammatory disease, affecting the small joints of the hands and feet. Chemokines and chemokine receptors play a critical role in RA pathogenesis via immune cells recruitment. Several chemokines and chemokine receptors are abundant in the peripheral blood and in the local inflamed joints of RA. Furthermore, synthetic and biologics disease modifying anti rheumatic drugs have been reported to affect chemokines expression. Thus, many studies have focused on targeting chemokines and chemokine receptors, where some have shown positive promising results. However, most of the chemokine blockers in human trials of RA treatment displayed some failures that can be attributed to several reasons in their structures and binding affinities. Nevertheless, targeting chemokines will continue to be under development, in order to improve their therapeutic potentials in RA and other autoimmune diseases. In this review we provide an up-to-date knowledge regarding the role of chemokines and chemokine receptors in RA with an emphasis on their activities on immune cells. We also discussed the effects of drugs targeting those molecules in RA. This knowledge might provide impetus for developing new therapeutic modalities to treat this chronic disease.

The Interrelationship Between Diabetes, IL-17 and Bone Loss

PURPOSE OF REVIEW

Diabetes has a detrimental effect on bone, increasing the risk of fracture and formation of osteolytic lesions such as those seen in periodontitis. Several diabetic complications are caused by diabetes-enhanced inflammation. This review examines mechanisms by which IL-17 contributes to diabetes-enhanced periodontitis and other effects of IL-17 on bone.

RECENT FINDINGS

IL-17 upregulates anti-bacterial defenses, yet its expression is also linked to a destructive host response in the periodontium. Periodontal disease is caused by bacteria that stimulate an inflammatory response. Diabetes-enhanced IL-17 increases gingival inflammation, which alters the composition of the oral microbiota to increase its pathogenicity. In addition, IL-17 can induce osteoclastogenesis by upregulation of TNF and RANKL in a number of cell types, and IL-17 has differential effects on osteoblasts and their progenitors. Increased IL-17 production caused by diabetes alters the pathogenicity of the oral microbiota and can promote periodontal bone resorption.

Biomarkers panels can predict fatigue, depression and pain in persons living with HIV: A pilot study

BACKGROUND

Persons living with HIV experience high symptom burden that can negatively impact medication adherence, work productivity, and quality of life. Symptoms are highly subjective, which can lead to under- or improper treatment. The purpose of this exploratory study was to examine relationships between circulating biomarkers representative of inflammatory, coagulation, and vascular function pathways and prevalent HIV symptoms.

SETTING AND SAMPLE

Adults >18 years who were diagnosed with HIV and spoke English for this cross-sectional study were recruited from community clinics and organizations.

METHODS

Symptom burden was measured with the HIV Symptom Index; depression with the Patient Health Questionnaire. Human multiplex kits were used to determine serum concentrations of select biomarkers representing inflammatory, coagulation, and vascular function pathways. The biomarkers were included as features in machine learning models to determine which biomarkers predicted the most prevalent HIV symptoms (fatigue and muscle/joint pain) and the symptom of depression.

RESULTS

Participants (N = 32) were representative of the local population of people with HIV, being mostly Black (54.4%) and male (60.6%). Depression was predicted by age, gender, glucose, hemoglobin A1c, and inflammation. Muscle/joint pain was predicted by adiponectin, C-reactive protein, and serum amyloid A (SAA). Fatigue was predicted by adiponectin, SAA, and soluble interleukin-1 receptor type II (sIL-1RII).

CONCLUSION

Biomarker clusters can be a tool to monitor symptoms. Adding an objective measure to subjective patient experiences could improve management and monitoring of symptoms. Defining a biomarker cluster for the objective assessment of HIV symptoms warrants further investigation; however, the presence of comorbid conditions needs to be controlled.

Th17/Treg cell level and clinical characteristics of peripheral blood of patients with Sjogren's syndrome complicated with primary biliary cirrhosis

This study aims at analyzing the Th17/Treg cell level and clinical characteristics of the peripheral blood of patients with Sjogren's syndrome (SS) complicated with primary biliary cirrhosis (PBC) so as to deepen the understanding of this disease and seek for its possible onset mechanism.A retrospective analysis was conducted on the clinical data of 24 patients [8 (33%) males and 16 (67%) females] with SS complicated with primary biliary cirrhosis, 50 patients with primary SS and 93 healthy volunteers. These patients were divided into 3 groups: experimental group (SS+PBC), control group (SS) and healthy group. Then, peripheral blood was collected and flow cytometry was conducted to detect level of Th17 cells and Treg cells. A fully automatic biochemical detector was used to detect the corresponding liver function index. The correlation analysis was made based on the clinical manifestations and biochemical characteristics.Compared with the healthy group and control group, the experimental group had the highest Th17/Treg cell ratio, and Th17 cell frequency was significantly increased (P <.05). Furthermore, ALT, AST, ALP, γ-GT, TBIL, and other indexes were positively correlated to the Th17/Treg ratio (P <.05).Th17/Treg cell level and its ratio in peripheral blood of patients with SS complicated with primary biliary cirrhosis were significantly unbalanced, indicating that Th17 cells participate in the onset of this disease to a large extent. Furthermore, the Th17/Treg ratio has a certain correlation with some of the liver function indexes, on which a stratified analysis could be made furtherly according to the seriousness of the conditions.

Diallyl Trisulfide can induce fibroblast-like synovial apoptosis and has a therapeutic effect on collagen-induced arthritis in mice via blocking NF-κB and Wnt pathways

BACKGROUND

Diallyl Trisulfide (DATS) is an organosulfur compound extracted from garlic bulb, and exerts cardioprotective, anti-inflammatory, antioxidant, antimicrobial and anticancer effects. But its role in the pathogenesis of rheumatoid arthritis (RA) is unknown. Here we explored the influence of DATS on human fibroblast-like synoviocytes (FLS) isolated from RA patients and a mouse model of collagen-induced arthritis (CIA) and the underlying mechanism.

METHODS

RA-FLS were cultured and treated with different concentrations of DATS. The CCK8 assay was used to assess cell proliferation while cell apoptosis was detected by flow cytometry and western blot. The IL-8, IL-6 and IL-1β levels were determined using RT-qPCR and ELISA assay. The expression of proteins of the NF-κB and Wnt pathways were measured using western blot. Furthermore, the effect of DATS was also explored in vivo using the collagen-induced arthritis mouse model. The Th17/Treg pattern obtain from cells of spleen of collagen-induced arthritis mouse model was detected by flow cytometry.

RESULTS

Our results showed that DATS could decrease cell viability and introduce apoptosis in RA-FLS. Furthermore, DATS significantly attenuated the production of key inflammatory cytokines induced by RA-FLS cells following treatment with tumor necrosis α (TNF-α) at a concentration of 100 μM or higher. This was due to its inhibitory effect on the NF-κB and Wnt pathway signaling in RA-FLS. Additionally, DATS decreased the production of inflammatory cytokines and regulated the immune function by restoring the balance between Th17 and Treg in CIA mouse model.

CONCLUSIONS

In conclusion, DATS may serve as a potential curative agent for RA.

Effect of Saururus chinensis leaves extract on type II collagen-induced arthritis mouse model

Background

Saururus chinensis leaves have been used as traditional medicine in Korea for pain, intoxication, edema, and furuncle. According to previous reports, these leaves exert renoprotective, neuroprotective, and antioxidant effects by attenuating inflammatory responses. However, the beneficial effect of Saururus chinensis leaves on arthritis has not been elucidated. Thus, we evaluated the water extract of Saururus chinensis leaves (SHW) using type II collagen-induced arthritis (CIA) mice models.

Methods

Quantitative analysis of major components from SHW was performed by HPLC. Arthritis was induced by injection of type II collagen. Each group was orally administered SHW (100 mg/kg and 500 mg/kg). Methotrexate (MTX) was used as a positive control. Serum levels of interleukin-6, TNF-alpha, and type II collagen IgG in the animal models were measured using ELISA. Histological features were observed by H&E staining.

Results

Quantitative analysis of SHW showed the contents as 56.4 ± 0.52 mg/g of miquelianin, 7.75 ± 0.08 mg/g of quercetin 3-O-(2”-O-β -glucopyranosyl)-α-rhamnopyranoside, and 3.17 ± 0.02 mg/g of quercitrin. Treatment with 500 mg/kg SHW decreased the serum level of Interleukin-6 (IL-6), TNF-alpha, and collagen IgG in the CIA model. Moreover, SHW treatment diminished the swelling of hind limbs and monocyte infiltration in blood vessels in CIA animal models. The results indicate that SHW could decrease CIA-induced arthritis in vivo.

Conclusions

The results indicate that SHW could be used to improving arthritis by reducing inflammatory factors (IL-6 and TNF-alpha). However, further experiments are required to determine how SHW influences signal transduction in animal models.

Electronic supplementary material

The online version of this article (10.1186/s12906-018-2418-z) contains supplementary material, which is available to authorized users.

Overexpression of CD64 on CD14++CD16- and CD14++CD16+ monocytes of rheumatoid arthritis patients correlates with disease activity

It is well-known that monocytes are a heterogeneous cell population and different monocyte subsets play important roles in rheumatoid arthritis (RA). Cluster of differentiation (CD)64 is one of Fc receptor, which initiates immunological and inflammatory reactions. However, the roles in RA remain to be elucidated. In the present study, the expression of CD64, CD40, CD163, CD206, HLA-DR, CD80 and CD86 on monocytes and the expression of CD64 on monocyte subsets were determined by flow cytometry. The expression of CD64 on monocyte subsets in patients with RA was further analyzed for their correlation with markers of autoimmune response, inflammation, disease activity of RA and serum cytokines. Compared to the health volunteers, the expression of CD64 on monocytes and each monocyte subset were significantly elevated in RA patients. The expression of CD64 on CD14⁺⁺CD16- and CD14++CD16+ monocytes were positively correlated with erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), rheumatoid factor (RF), anti-citrullinated protein antibodies (ACPA) and disease activity score 28 (DAS28). Furthermore, the expression of CD64 on CD14++CD16+ monocytes was found to be associated with the serum level of IL-6. In conclusions, these data demonstrated the expression of CD64 on CD14++CD16- and CD14++CD16+ monocytes are elevated and associated with the disease activity in RA.

Osteoclast-Derived Extracellular Vesicles: Novel Regulators of Osteoclastogenesis and Osteoclast-Osteoblasts Communication in Bone Remodeling

Extracellular vesicles (EVs), including exosomes, microvesicles, and apoptotic bodies, play an important role in cellular communication during skeletal growth and homeostasis. Bioactive molecules carried by EVs are transported to neighboring and distant cells to trigger a series of signaling cascades influencing bone homeostasis. The bioactive activities of osteoclast-derived EVs include regulation of osteoclastogenesis and osteoclast–osteoblast communication. As osteoclast-derived EVs have the potential to regulate osteoclasts and osteoblasts, their application in osteoporosis and other bone metabolic disorders is currently under investigation. However, very few reviews of osteoclast-derived EVs in bone remodeling regulation have yet been published. This article aims to review recent advances in this field, summarizing a new regulator of osteoclastogenesis and osteoclast–osteoblast communication mediated by osteoclast-derived EVs. We will analyze the major challenges in the field and potential for the therapeutic application of EVs.

IL-17A Inhibits Osteogenic Differentiation of Bone Mesenchymal Stem Cells via Wnt Signaling Pathway

Background

Interleukin-17A (IL-17A) is not only an important modulator of inflammatory reactions, but also affects bone metabolism, which is involved in osteogenic differentiation of stem cells. However, the role and mechanism of IL-17A in osteogenic differentiation of bone mesenchymal stem cells (BMSCs) are not fully understood. In this study, we investigated the role and mechanism of IL-17A in osteogenic differentiation of BMSCs.

Material/Methods

The osteogenic differentiation of BMSCs was induced by osteoblast-induction medium with IL-17A or without IL-17A. The osteogenic differentiation of BMSCs was confirmed by the alkaline phosphatase and alizarin red staining. The lentiviral plasmid was used to construct the sFRP1-shRNA expression vector. The associated osteogenic differentiation marks (RUNX2, ALP, OPN), Wnt signaling pathway inhibitor (sFRP1), and modulators of Wnt signaling pathway (Wnt3, Wnt6) were detected by qRT-PCR and Western blot method.

Results

The results showed that the addition of IL-17A inhibited osteogenic differentiation of BMSCs. IL-17A induced up-regulated expression of sFRP1 and down-regulated expression of Wnt3 and Wnt6 in BMSCs. In addition, sFRP1-shRNA abolished the inhibition effect of IL-17A in osteogenic differentiation of BMSCs and induced up-regulated expression of Wnt3 and Wnt6 in the Wnt signaling pathway in BMSCs.

Conclusions

Our findings show that IL-17A inhibits osteogenic differentiation of bone mesenchymal stem cells via the Wnt signaling pathway.

Interleukin-17A Levels Increase in Serum of Children With Juvenile Idiopathic Arthritis

Objectives

This study aims to determine the serum levels of interleukin-17A (IL-17A) in children with juvenile idiopathic arthritis (JIA) and analyze the correlation between IL-17A values and disease activity, certain clinical features, and laboratory markers of inflammation.

Patients and methods

The study included 30 children (7 boys, 23 girls; mean age 8.8±5.3 years; range 1 to 18 years), who had been diagnosed with JIA (18 children were diagnosed during the study period and 12 children were diagnosed before the start of the study) and had active disease during the study period. Control group included 30 healthy, age- and sex- matched children (9 boys, 21 girls; mean age 8.3±4.8 years; range 1 to 18 years). The enzyme-linked immunosorbent assay was used to assess the serum IL-17A levels of children with JIA in the active phase of the disease and control group. Clinical and laboratory features of the disease were evaluated for the children with JIA.

Results

Serum levels of IL-17A in children with JIA were significantly higher in comparison to control group. In children with JIA who were prospectively monitored, statistically significantly decreased IL-17A level was recorded in the inactive phase of the disease. The incidence of arthritis of coxofemoral joints was significantly more common, and the mean levels of erythrocyte sedimentation rate and C-reactive protein were significantly higher in the group of children with JIA with detectable levels of IL-17A. Children with JIA and detectable levels of IL-17A had significantly higher values of Juvenile Arthritis Disease Activity Score-27 in comparison to children with JIA and non-detectable IL-17A.

Conclusion

Assessment of serum IL-17A levels in early phases of JIA gives an opportunity for early detection of children that have higher risk for worse functional outcome.

Elevated Expression of Immunoreceptor Tyrosine-Based Inhibitory Motif (TIGIT) on T Lymphocytes is Correlated with Disease Activity in Rheumatoid Arthritis

Background

It is well known that lymphocytes play an important role in rheumatoid arthritis (RA). T cell immunoreceptors with immunoglobulin (Ig) and immunoreceptor tyrosine-based inhibitory motif (TIGIT) have immunosuppressive co-stimulatory molecules that mediate inhibitory effects, but their roles in RA are poorly understood.

Material/Methods

Were recruited 76 patients with RA and 33 healthy controls (HC). Clinical manifestations, laboratory measurements, physical examination, and medical history of RA patients were recorded. The expression of TIGIT on CD3⁺ T lymphocytes, B lymphocytes, monocytes, neutrophils, CD3⁺CD4⁺ T lymphocytes, and CD3⁺CD8⁺ T lymphocytes was determined using flow cytometry. The expression of TIGIT on T lymphocytes in patients with RA was further analyzed to investigate its correlations with markers of autoimmune response, inflammation, and disease activity in RA.

Results

Compared with HC, the expression levels of TIGIT on CD3⁺CD4⁺ T lymphocytes and CD3⁺CD8⁺ T lymphocytes were significantly increased in patients with RA (P < 0.01). The frequency of TIGIT-expressing CD3⁺CD4⁺ T lymphocytes was positively correlated with RF, increased ACPA, ESR, and CRP levels. The frequency of TIGIT-expressing CD3⁺CD8⁺ T lymphocytes was positively correlated with RF and ESR levels. Furthermore, the expression level of TIGIT on CD3⁺CD4⁺ T lymphocytes was positively correlated with the DAS28 score in RA.

Conclusions

The expression levels of TIGIT on T lymphocytes were elevated and correlated with disease activity in RA.

Fibroblast-like synoviocytes-dependent effector molecules as a critical mediator for rheumatoid arthritis: Current status and future directions

Rheumatoid arthritis (RA) is a systemic-autoimmune-mediated disease characterized by synovial hyperplasia and progressive destruction of joint. Currently available biological agents and inhibitor therapy that specifically target tumor necrosis factor-α, interleukin 1β (IL-1β), IL-6, T cells, B cells, and subcellular molecules (p38 mitogen-activated protein kinase and janus kinase) cannot facilitate complete remission in all patients and are unable to cure the disease. Therefore, further potent therapeutic targets need to be identified for effective treatment and successful clinical outcomes in patients with RA. Scientific breakthroughs have brought new insights regarding fibroblast-like synoviocytes (FLS), a major constituent of the synovial hyperplasia. These play a pivotal role in RA invading cartilage and bone tissue. Currently there are no effective therapies available that specifically target these aggressive cells. Recent evidences indicate that FLS-dependent effector molecules (toll-like receptors, nodal effector molecules, hypoxia-inducible factor, and IL-17) have emerged as important mediators of RA. In this review, we discuss the pathological features and recent advances in understanding the role of FLS-dependent effector molecules in the disease onset of RA. Pharmacological inhibition of FLS-dependent effector molecules might be a promising option for FLS-targeted therapy in RA.

The Roles of Acidosis in Osteoclast Biology

The adverse effect of acidosis on the skeletal system has been recognized for almost a century. Although the underlying mechanism has not been fully elucidated, it appears that acidosis acts as a general stimulator of osteoclasts derived from bone marrow precursors cells and enhances osteoclastic resorption. Prior work suggests that acidosis plays a significant role in osteoclasts formation and activation via up-regulating various genes responsible for its adhesion, migration, survival and bone matrix degradation. Understanding the role of acidosis in osteoclast biology may lead to development of novel therapeutic approaches for the treatment of diseases related to low bone mass. In this review, we aim to discuss the recent investigations into the effects of acidosis in osteoclast biology and the acid-sensing molecular mechanism.

Total flavonoids of Bidens bipinnata L. ameliorate experimental adjuvant-induced arthritis through induction of synovial apoptosis

BACKGROUND

Bidens bipinnata are widely distributed in China, which have been widely used as a traditional Chinese medicine. The aim of this study was to examine the effect of total flavonoids of Bidens pilosa L. (TFB) on adjuvant arthritis (AA) and its possible mechanisms.

METHODS

The macroscopic scoring of paw edema, secondary paw swelling, and polyarthritis index were measured. Histological examination of the joints and the serum concentrations of IL-6, IL-1beta, and TNF-alpha were examined. Apoptosis in synovial tissue was detected. The expression of Caspase 3 cleavage, serves as a marker undergoing apoptosis, was confirmed by Western blot.

RESULTS

TFB attenuated the severity of arthritis on paw edema, hind paw volume, and polyarthritis index of AA rats, improved the histological status in AA rats as well. TFB can inhibit the production of IL-6, IL-1beta, and TNF-alpha from serum. Clear DNA ladder formation was observed in DNA extraction of synovium from TFB treated AA rats. The number of apoptosis was increased with TFB treatment in TUNEL assay. TFB treatment on AA rats significantly increased the expression of Caspase 3 in synovium.

CONCLUSIONS

Our data suggest that TFB has a significant anti-arthritic effect in AA through the induction of apoptosis in synovial.

Lapatinib ameliorates experimental arthritis in rats

Epidermal growth factor receptor (EGFR) and its ligands are commonly expressed by synovial cells. The aim of the present study was to detect the potential effect of lapatinib an inhibitor of EGFR tyrosine kinases on collagen-induced arthritis. Thirty Wistar albino female rats were randomized into three groups. Arthritis was induced by intradermal injection of chicken type II collagen with incomplete Freund's adjuvant. Serum TNF-α, IL-17, and malondialdehyde (MDA) levels were analyzed. Tissue superoxide dismutase (SOD), catalase and glutathione peroxidase (GPx) activities, and nuclear factor erythroid 2-related factor-2 (Nrf2) and heme oxgenase-1 (HO-1) expressions were determined. TNF-α, IL-17 and MDA levels, and Nrf2 and HO-1 expressions were lower in lapatinib-treated (30 mg/kg/day) group compared to sham group, while SOD, catalase, and GPx activities were higher (p < 0.05). Moreover, lapatinib ameliorated perisynovial inflammation and cartilage-bone destruction (p < 0.001). In conclusion, EGFR may have prominent pathogenic role and lapatinib may be an effective therapeutic option for arthritis.

The role of "bone immunological niche" for a new pathogenetic paradigm of osteoporosis

Osteoporosis is characterized by low bone mass and microarchitectural deterioration of bone tissue. The etiology and pathogenetic mechanisms of osteoporosis have not been clearly elucidated. Osteoporosis is linked to bone resorption by the activation of the osteoclastogenic process. The breakdown of homeostasis among pro- and antiosteoclastogenic cells causes unbalanced bone remodeling. The complex interactions among these cells in the bone microenvironment involve several mediators and proinflammatory pathways. Thus, we may consider the bone microenvironment as a complex system in which local and systemic immunity are regulated and we propose to consider it as an "immunological niche." The study of the "bone immunological niche" will permit a better understanding of the complex cell trafficking which regulates bone resorption and disease. The goal of a perfect therapy for osteoporosis would be to potentiate good cells and block the bad ones. In this scenario, additional factors may take part in helping or hindering the proosteoblastogenic factors. Several proosteoblastogenic and antiosteoclastogenic agents have already been identified and some have been developed and commercialized as biological therapies for osteoporosis. Targeting the cellular network of the "bone immunological niche" may represent a successful strategy to better understand and treat osteoporosis and its complications.

DNA methylation: roles in rheumatoid arthritis

Rheumatoid arthritis (RA) is an immune-mediated disease of unknown cause that primarily affects the joints and ultimately leads to joint destruction. In recent years, the potential role of DNA methylation in the development of RA is raising great expectations among clinicians and researchers. DNA methylation influences diverse aspects of the disease and regulates epigenetic silencing of genes and behavior of several cell types, especially fibroblast-like synoviocytes (FLS), the most resident cells in joints. The activation of FLS is generally regarded as a key process in the development of RA that actively results in the promotion of ongoing inflammation and joint damage. It has also been shown that aberrant DNA methylation occurs in the pathogenesis of RA and contributes to the development of the disease. Recently, there has been an impressive increase in studies involving DNA methylation in RA. In this paper, we consider the role of DNA methylation in the development of RA.

Changes of serum cytokines-related Th1/Th2/Th17 concentration in patients with postmenopausal osteoporosis

BACKGROUND

Postmenopausal osteoporosis is now hypothetically considered to be an autoimmune and inflammatory process in which many pro-inflammatory and T cell-derived cytokines play important roles in the loss of bone mass. For instance, interleukin-2 (IL-2), interferon-γ (IFN-γ), and tumor necrosis factor-α (TNF-α) secreted by Th1 and IL-6, IL-4, and IL-10 secreted by Th2 have been shown to be involved in the pathogenesis of osteoporosis. Interleukin-17 (IL-17) is a characteristic cytokine secreted by Th17 cells of the CD4 + subgroup. Although IL-17 has been shown to enhance bone resorption in ovariectomized mouse model, bone cells and genetic research, human-related studies of IL-17 are few.

METHODS

According to WHO classification of osteoporosis by the T scores of BMD, the subjects were divided into the postmenopausal osteoporosis group (T scores≤-2.5), the postmenopausal osteopenia group (-2.5 < T scores<-1), and the postmenopausal normal BMD group (T scores≥-1); 30 subjects in each group. Cytometric bead array (CBA) technique was employed for serum determination of the primary indexes including IL-17A, IL-2, IFN-γ, TNF-α, IL-6, IL-4, and IL-10 concentrations in the 90 volunteers. In the meantime, serum calcium, phosphorus, magnesium, and alkaline phosphatase concentrations were also determined in the patients. One-way analysis of variance (one-way ANOVA) was employed in data analysis to determine whether the testing results of various parameters had significant differences. The bivariate correlation was tested with the Pearson correlation coefficient. When p < 0.05, the difference was considered to have statistical significance.

RESULTS

Serum IL-17A concentration was significantly higher in the postmenopausal osteoporosis group than in the postmenopausal osteopenia group and the postmenopausal normal BMD group, but the difference between the postmenopausal osteopenia group and the postmenopausal normal BMD group had no statistical significance. IL-17A was negatively correlated with BMD. To our knowledge, we discovered for the first time that serum concentrations of IFN-γ and IL-4 were significantly lower in the postmenopausal osteoporosis group than in the postmenopausal normal BMD group; IFN-γ and IL-4 were positively correlated with BMD. In addition, we also determined that BMI was negatively correlated with BMD; IL-17A was positively correlated with serum calcium. However, no significant differences in IL-6, TNF-α, IL-2, and IL-10 were observed among the three groups; these three factors were not correlated with BMD.

CONCLUSIONS

Our experiments have confirmed the roles of IL-17 in the pathogenesis of postmenopausal osteoporosis and in the promotion of bone resorption. Targeted therapy of IL-17, IFN-γ, and IL-4 may be beneficial in the treatment of patients with postmenopausal osteoporosis. Our experiments have also confirmed the roles of IFN-γ and IL-4 in the pathogenesis of postmenopausal osteoporosis and in the inhibition of bone resorption.

Effects of Interleukin-17A on Osteogenic Differentiation of Isolated Human Mesenchymal Stem Cells

OBJECTIVES

Rheumatoid arthritis (RA) is characterized by defective bone repair and excessive destruction and ankylosing spondylitis (AS) by increased ectopic bone formation with syndesmophytes. Since TNF-α and IL-17A are involved in both diseases, this study investigated their effects on the osteogenic differentiation of isolated human bone marrow-derived mesenchymal stem cells (hMSCs).

METHODS

Differentiation of hMSCs into osteoblasts was induced in the presence or absence of IL-17A and/or TNF-α. Matrix mineralization (MM) was evaluated by alizarin red staining and alkaline phosphatase (ALP) activity. mRNA expression was measured by qRT-PCR for bone morphogenetic protein (BMP)-2 and Runx2, genes associated with osteogenesis, DKK-1, a negative regulator of osteogenesis, Schnurri-3 and receptor activator of nuclear factor kappa B ligand (RANKL), associated with the cross talk with osteoclasts, and TNF-α receptor type I and TNF-α receptor type II (TNFRII).

RESULTS

TNF-α alone increased both MM and ALP activity. IL-17A alone increased ALP but not MM. Their combination was more potent. TNF-α alone increased BMP2 mRNA expression at 6 and 12 h. These levels decreased in combination with IL-17A at 6 h only. DKK-1 mRNA expression was inhibited by TNF-α and IL-17A either alone or combined. Supporting an imbalance toward osteoblastogenesis, RANKL expression was inhibited by TNF-α and IL-17A. However, TNF-α but not IL-17 alone decreased Runx2 mRNA expression at 6 h. In parallel, TNF-α but not IL-17 alone increased Schnurri-3 expression with a synergistic effect with their combination. This may be related to an increase of TNFRII overexpression.

CONCLUSION

IL-17 increased the effects of TNF-α on bone matrix formation by hMSCs. However, IL-17 decreased the TNF-α-induced BMP2 inhibition. Synergistic interactions between TNF-α and IL-17 were seen for RANKL inhibition and Schnurri-3 induction. Such increase of Schnurri-3 may in turn activate osteoclasts leading to bone destruction as in RA. Conversely, in the absence of osteoclasts, this could promote ectopic bone formation as in AS.

Halofuginone ameliorates autoimmune arthritis in mice by regulating the balance between Th17 and Treg cells and inhibiting osteoclastogenesis

OBJECTIVE

The small molecule halofuginone has been shown to inhibit fibrosis, angiogenesis, and tumor progression. This study was undertaken to evaluate the effects of halofuginone in preventing autoimmune arthritis in mice.

METHODS

The effects of halofuginone on joint diseases were assessed by clinical scoring and histologic analysis. Protein expression levels were confirmed by immunohistochemistry, enzyme-linked immunosorbent assay, flow cytometry, and/or Western blotting. The expression levels of messenger RNA (mRNA) for various molecules were determined by real-time polymerase chain reaction (PCR). Proliferation of osteoclast precursors was assessed by bromodeoxyuridine uptake. Osteoclast differentiation and activity were determined by quantifying tartrate-resistant acid phosphatase (TRAP)-positive multinucleated cells and area of resorbed bone.

RESULTS

Treatment with halofuginone suppressed the development of autoimmune arthritis and reciprocally regulated Th17 cells and FoxP3+ Treg cells. These effects of halofuginone on Th17 differentiation involved increased signaling of ERK and reduction of STAT-3 and NF-ATc1 expression. Furthermore, halofuginone induced the expression of indoleamine 2,3-dioxygenase (IDO) in dendritic cells, leading to reduced production of Th17 cells. In addition, halofuginone prevented the formation and activity of osteoclasts through suppression of transcription factors, such as activator protein 1 and NF-ATc1, and inhibited cell cycle arrest by the committed osteoclast precursors via expression of Ccnd1 encoding cyclin D1.

CONCLUSION

Taken together, our results suggest that halofuginone is a promising therapeutic agent for the treatment of Th17 cell-mediated inflammatory diseases and bone diseases.

ADAMTS-12: a multifaced metalloproteinase in arthritis and inflammation

ADAMTS-12 is a member of a disintegrin and metalloproteinase with thrombospondin motifs (ADAMTS) family of proteases, which were known to play important roles in various biological and pathological processes, such as development, angiogenesis, inflammation, cancer, arthritis, and atherosclerosis. In this review, we briefly summarize the structural organization of ADAMTS-12; concentrate on the emerging role of ADAMTS-12 in several pathophysiological conditions, including intervertebral disc degeneration, tumorigenesis and angioinhibitory effects, pediatric stroke, gonad differentiation, trophoblast invasion, and genetic linkage to schizophrenia and asthma, with special focus on its role in arthritis and inflammation; and end with the perspective research of ADAMTS-12 and its potential as a promising diagnostic and therapeutic target in various kinds of diseases and conditions.

Th17 Cells in Immunopathogenesis and treatment of rheumatoid arthritis

Rheumatoid arthritis (RA) is a chronic inflammatory disease characterized by the sequestration of various leukocyte subpopulations within both the developing pannus and synovial space. The chronic nature of this disease results in inflammation of multiple joints, with subsequent destruction of the joint cartilage and erosion of bone. Identification of T helper (Th)17 cells led to breaking the dichotomy of the Th1/Th2 axis in immunopathogenesis of autoimmune diseases such as RA, and its experimental model, collagen-induced arthritis (CIA). Th17 cells produce cytokines, including interleukin (IL)-17, IL-6, IL-21, IL-22 and tumor necrosis factor (TNF)-α, with pro-inflammatory effects, which appear to have a role in immunopathogenesis of RA. Regarding the wide ranging production of pro-inflammatory cytokines and chemokines by Th17 cells, it is expected that Th17 cell could be a potent pathogenic factor in disease immunopathophysiology. Thus the identification of effector mechanisms used by Th17 cells in induction of disease lesions may open new prospects for designing a new therapeutic strategy for treatment of RA.

Expression of TIM-3 on CD4+ and CD8+ T cells in the peripheral blood and synovial fluid of rheumatoid arthritis

Rheumatoid arthritis (RA) is characterized by a chronic inflammatory process that targets the synovial lining of diarthrodial joints. TIM-3 plays a key role in the negative regulation of the immune response. In this study, we investigated the expression of TIM-3 on CD4+ and CD8+ T cells from systemic (peripheral blood) and local (synovial fluid) perspectives of RA. Level of TIM-3+ cells from peripheral blood and synovial fluid of patients as well as peripheral blood of healthy controls was measured by flow cytometry. Results showed that TIM-3 expression was significantly increased in both CD4+ and CD8+ T cells in the peripheral blood of RA (p < 0.001 and p < 0.001, respectively). Furthermore, patients revealed even higher expression of TIM-3 in CD4+ and CD8+ T cells in synovial fluid than in peripheral blood. When comparing TIM-3 level with the severity of RA, we identified that the percentage of TIM-3 on both peripheral CD4+ and peripheral CD8+ T cells was negatively correlated with disease activity score 28 (DAS28) of the patients. Similarly, TIM-3 on synovial fluid CD4+ and CD8+ T cells also revealed inverse correlation with DAS28 of the cases. Our data demonstrate a negative correlation between TIM-3 and the disease progression of RA.

IL-17 inhibits chondrogenic differentiation of human mesenchymal stem cells

OBJECTIVE

Mesenchymal stem cells (MSCs) can differentiate into cells of mesenchymal lineages, such as osteoblasts and chondrocytes. Here we investigated the effects of IL-17, a key cytokine in chronic inflammation, on chondrogenic differentiation of human MSCs.

METHODS

Human bone marrow MSCs were pellet cultured in chondrogenic induction medium containing TGF-β3. Chondrogenic differentiation was detected by cartilage matrix accumulation and chondrogenic marker gene expression.

RESULTS

Over-expression of cartilage matrix and chondrogenic marker genes was noted in chondrogenic cultures, but was inhibited by IL-17 in a dose-dependent manner. Expression and phosphorylation of SOX9, the master transcription factor for chondrogenesis, were induced within 2 days and phosphorylated SOX9 was stably maintained until day 21. IL-17 did not alter total SOX9 expression, but significantly suppressed SOX9 phosphorylation in a dose-dependent manner. At day 7, IL-17 also suppressed the activity of cAMP-dependent protein kinase A (PKA), which is known to phosphorylate SOX9. H89, a selective PKA inhibitor, also suppressed SOX9 phosphorylation, expression of chondrogenic markers and cartilage matrix, and also decreased chondrogenesis.

CONCLUSIONS

IL-17 inhibited chondrogenesis of human MSCs through the suppression of PKA activity and SOX9 phosphorylation. These results suggest that chondrogenic differentiation of MSCs can be inhibited by a mechanism triggered by IL-17 under chronic inflammation.

Advances in understanding the pathogenesis of autoimmune disorders: focus on chemokines and lymphocyte trafficking

Lymphocyte trafficking is a key step in the pathogenesis of various autoimmune diseases. Recruitment of autoreactive lymphocytes to inflamed tissues is a defining feature of numerous persistent organ-specific autoimmune conditions and various therapies are now used in several of these diseases which appear to specifically block lymphocyte migration. Thus, better understanding of the molecular events involved in homing of autoreactive pathogenic lymphocytes may present novel opportunities for pharmacological intervention in autoimmune diseases, such as multiple sclerosis, rheumatoid arthritis, type-1 diabetes and psoriasis. This review describes recent progress in understanding lymphocyte trafficking in autoimmunity, focusing on the involvement of the chemokine and chemokine receptor superfamily. Possible strategies to improve therapeutics for autoimmune diseases arising from these studies are discussed.

Differential arthritogenicity of Staphylococcus aureus strains isolated from biological samples

BACKGROUND

Staphylococcus aureus is the most common agent of septic arthritis that is a severe, rapidly progressive and destructive joint disease. Superantigens produced by S. aureus are considered the major arthritogenic factors. In this study, we compared the arthritogenic potential of five superantigen-producing staphylococcal strains.

METHODS

Male C57BL/6 mice were intravenously infected with ATCC 19095 SEC+, N315 ST5 TSST-1+, S-70 TSST-1+, ATCC 51650 TSST-1+ and ATCC 13565 SEA+ strains. Clinical parameters as body weight, arthritis incidence and clinical score were daily evaluated. Joint histopathological analysis and spleen cytokine production were evaluated at the 14th day after infection.

RESULTS

Weight loss was observed in all infected mice. ATCC 19095 SEC+, N315 ST5 TSST-1+ and S-70 TSST-1+ were arthritogenic, being the highest scores observed in ATCC 19095 SEC+ infected mice. Intermediate and lower clinical scores were observed in N315 ST5 TSST-1+ and S-70 TSST-1+ infected mice, respectively. The ATCC 13565 SEA+ strain caused death of 85% of the animals after 48 h. Arthritis triggered by the ATCC 19095 SEC+ strain was characterized by accentuated synovial hyperplasia, inflammation, pannus formation, cartilage destruction and bone erosion. Similar joint alterations were found in N315 ST5 TSST-1+ infected mice, however they were strikingly more discrete. Only minor synovial proliferation and inflammation were triggered by the S-70 TSST-1+ strain. The lowest levels of TNF-α, IL-6 and IL-17 production in response to S. aureus stimulation were found in cultures from mice infected with the less arthritogenic strains (S-70 TSST-1+ and ATCC 51650 TSST-1+). The highest production of IL-17 was detected in mice infected with the most arthritogenic strains (ATCC 19095 SEC+ and N315 ST5 TSST-1+).

CONCLUSIONS

Together these results demonstrated that S. aureus strains, isolated from biological samples, were able to induce a typical septic arthritis in mice. These results also suggest that the variable arthritogenicity of these strains was, at least in part, related to their differential ability to induce IL-17 production.

Screening of osteoprotegerin-related feature genes in osteoporosis and functional analysis with DNA microarray

Background

Osteoporosis affects 200 million people worldwide and places an enormous economic burden on society. We aim to identify the feature genes that are related to osteoprotegerin in osteoporosis and to perform function analysis with DNA microarray from human bone marrow.

Methods

We downloaded the gene expression profile GSE35957 from Gene Expression Omnibus database including nine gene chips from bone marrow mesenchymal stem cells of five osteoporotic and four non-osteoporotic subjects. The differentially expressed genes between normal and disease samples were identified by LIMMA package in R language. The interactions among the osteoprotegerin gene (OPG) and differentially expressed genes were searched and visualized by Cytoscape. MCODE and Bingo were used to perform module analysis. Finally, GENECODIS was used to obtain enriched pathways of genes in an interaction network.

Results

A total of 656 genes were identified as differentially expressed genes between osteoporotic and non-osteoporotic samples. IL17RC, COL1A1, and ESR1 were identified to interact with OPG directly from the protein-protein interaction network. A module containing ERS1 was screened out, and this module was most significantly enriched in organ development. Pathway enrichment analysis suggested genes in the interaction network were related to focal adhesion.

Conclusions

The expression pattern of IL17RC, COL1A1, and ESR1 can be useful in osteoporosis detection, which may help in identifying those populations at high risk for osteoporosis, and in directing treatment of osteoporosis.

Metformin downregulates Th17 cells differentiation and attenuates murine autoimmune arthritis

INTRODUCTION

This study was undertaken to determine whether metformin has anti-inflammatory effects in the collagen antibody-induced arthritis (CAIA) murine model. The effect of metformin on Th17 cell differentiation was also investigated.

METHODS

CAIA mice were treated with 100 and 150 mg/kg i.p. metformin (low- and high-dose groups, respectively). Arthritis activity and histological joint destruction were studied. Flow cytometry was used to (i) determine RORγt-expressing CD4+ percentages in draining axillary lymph nodes (ALNs) from metformin-treated and untreated mice with CAIA, (ii) determine Th17 percentages in splenic CD4+ T cells cultured ex vivo for 3 days in Th17-differentiation-inducing conditions, and (iii) determine the percentages of RORγt+CD4+ T cells when normal splenic T cells from DBA/1 mice were cultured in Th17-differentiation-inducing conditions together with various metformin doses. Western blot analysis was used to assess the intracellular signaling of the metformin-treated splenocytes.

RESULTS

Metformin attenuated both arthritis scores and bone destruction in CAIA mice, decreased the serum levels of the pro-inflammatory cytokines, TNF-α and IL-1, and reduced the number of RORγt+CD4+ T cells in the ALNs. Splenocytes from metformin-treated CAIA mice differentiated less readily into Th17 cells upon ex vivo stimulation. Metformin treatment of normal cells cultured in Th17-differentiation-inducing conditions decreased the number of RORγt-expressing CD4+ cells in a dose-dependent manner and downregulated STAT3 phosphorylation via the AMPK pathway.

CONCLUSIONS

Metformin had an anti-inflammatory effect on murine autoimmune arthritis due to the inhibition of Th17 cell differentiation. Metformin may have a possible therapeutic value for treatment of rheumatoid arthritis.

The microbial capsular polysaccharide galactoxylomannan inhibits IL-17A production in circulating T cells from rheumatoid arthritis patients

The persistence of activated T cells in rheumatoid arthritis (RA) synovium may be attributable to increased homing, increased retention or a possible imbalance between cell proliferation and programmed cell death. Induction of apoptosis may represent a potential therapeutic approach. Galactoxylomannan (GalXM) from the opportunistic fungus Cryptococcus neoformans can interact with T cells and induce T-cell apoptosis through the inhibition of CD45 phosphatase activity. The aim of this study was to determine the effect of GalXM on circulating T cells from patients with RA and the underlying mechanisms. GalXM immunomodulating effect on apoptosis and signal transduction pathway involved in IL-17A production was evaluated on T cells. RA T-cell apoptosis, higher than that of control T cells, was further increased by GalXM through induction of caspase-3 activation. Activated T cells expressing the CD45RO molecule and producing IL-17A were the main target of GalXM-induced apoptosis. GalXM induced consistent impairment of IL-17A production and inhibition of STAT3, which was hyperactivated in RA. In conclusion, GalXM triggered apoptosis of activated memory T cells and interfered with IL-17A production in RA. These data suggest therapeutic targeting of deleterious Th17 cells in RA and other autoimmune diseases.

Influence of infliximab on cytokines network and markers of bone remodeling in rheumatoid arthritis patients

PURPOSE

Our aim was to determine the effects of infliximab on bone mineral metabolism in rheumatoid arthritis (RA) patients and analyze the relationship between inflammatory markers of acute phase thought to play a major role in bone remodeling.

MATERIALS AND METHODS

36 patients with established RA were investigated. All patients underwent physical examination and blood and urinary analysis at baseline, 2 weeks, 14 weeks, 6 months and 12 months after the initiation of treatment. The serum levels of: tumor necrosis factor alpha (TNF-alpha), tumor necrosis factor alpha receptor 1 (TNFR1), TNFR2, interleukin 6 (IL-6), IL-17, IL-23 and markers of bone remodeling such as osteocalcin (BGP), deoxypyridynoline (Dpd), and N-telopeptide of type I collagen (NTx) were measured by ELISA.

RESULTS

The results showed significant decrease of all the above cytokines levels in RA patients in comparison with those after 2 weeks of treatment. After 6 months, the markers of bone formation and resorption decreased compared to baseline values. We found positive correlation between the levels of NTx and the levels of IL-6, IL-17 and TNFR1, and between the levels of Dpd and IL-6 and Dpd and TNFR2, whereas negative correlation between BGP and IL-23. After 12 months the positive association was found at the BGP level and IL-6 as well as Dpd and the level of IL-6. We also observed a positive relation between Dpd and TNF-alpha and negative between BGP and TNFR1.

CONCLUSION

We suggest that infliximab treatment may limit the risk of osteoporosis in RA patients.

Epidermal growth factor receptor (EGFR) as a therapeutic target in rheumatoid arthritis

The epidermal growth factor receptor (EGFR) has an important role in the hyperplastic growth of tumor. Similar to tumor growth, rheumatoid arthritis (RA) synovium is hyperplastic, invasive, and expresses EGFR and its ligands. Activation of EGFR signaling is responsible for synovial fibroblast proliferation in RA. Furthermore, in addition to its role in proliferation, EGFR and its ligands can induce cytokine production of synovial fibroblasts during the pathogenesis of RA. Agents that target EGFR have yielded promising results in animal experiments involving RA, pharmacologic modulations targeting EGFR, or its ligands may give rise to new therapeutic approaches for RA. In this review article, we will discuss the biological features of EGFR and summarize recent advances regarding the role of EGFR in the pathogenesis and treatment of RA.

Immunopathogenesis of non-healing American cutaneous leishmaniasis and progressive visceral leishmaniasis

The outcomes of Leishmania infection are determined by host immune and nutrition status, parasite species, and co-infection with other pathogens. While subclinical infection and self-healing cutaneous leishmaniasis (CL) are common, uncontrolled parasite replication can lead to non-healing local lesions or visceral leishmaniasis (VL). It is known that infection control requires Th1-differentiation cytokines (IL-12, IL-18, and IL-27) and Th1 cell and macrophage activation. However, there is no generalized consensus for the mechanisms of host susceptibility. The recent studies on regulatory T cells and IL-17-producing cells help explain the effector T cell responses that occur independently of the known Th1/Th2 cell signaling pathways. This review focuses on the immunopathogenesis of non-healing American CL and progressive VL. We summarize recent evidence from human and animal studies that reveals the mechanisms of dysregulated, hyper-responses to Leishmania braziliensis, as well as the presence of disease-promoting or the absence of protective responses to Leishmania amazonensis and Leishmania donovani. We highlight immune-mediated parasite growth and immunopathogenesis, with an emphasis on the putative roles of IL-17 and its related cytokines as well as arginase. A better understanding of the quality and regulation of innate immunity and T cell responses triggered by Leishmania will aid in the rational control of pathology and the infection.

T cell immunoglobulin-3 as a new therapeutic target for rheumatoid arthritis

T cell immunoglobulin-3 (Tim-3) is a surface molecule expressed on various cell types of the immune system which plays a central role in immune regulation. Recently, identification of galectin-9 (Gal-9) as a ligand for Tim-3 has established the Tim-3-Gal-9 pathway as an important regulator of Th1 immunity and induction of tolerance. The interaction of Tim-3 with Gal-9 induces cell death; the in vivo blockade of this interaction results in exacerbated autoimmunity and abrogation of tolerance in experimental models, thus establishing Tim-3 as a negative regulatory molecule. A number of previous studies have demonstrated that Tim-3 influences chronic autoimmune diseases, such as multiple sclerosis and systemic lupus erythematosus. In addition, an association between Tim-3 polymorphisms and susceptibility to several autoimmune diseases has been identified in various autoimmune diseases, including rheumatoid arthritis (RA). Recent work has focused on the role of Tim-3 in RA, and the results indicate that Tim-3 may represent a novel target for the treatment of RA. In this article we will discuss the Tim-3 pathway and the therapeutic potential of modulating the Tim-3 pathway in RA.

Increased frequency of Th17 cells in the peripheral blood of children infected with enterovirus 71

Enterovirus 71 (EV71) affects the health of young children globally causing severe neurologic diseases. The relationship between EV71 infection and T helper type 17 (Th17) has not been described, although this new Th subset or interleukin-17 (IL-17) has been reported to be associated with other viral infections. The purpose of the current study was to describe the immune profile involving Th17 cells, neutrophils, and related factors and to speculate on the possible immunopathogenesis of EV71 infections. Flow cytometry and an automatic blood cell counter were used to analyze circulating Th17 cells and count neutrophils, respectively. Expression of acid-related orphan nuclear receptor gamma t (ROR γt) was evaluated by reverse-transcriptional PCR, and enzyme linked immunosorbent assays (ELISAs) were used for detecting concentrations of IL-17, IL-23, and IFN-γ. The results showed that the frequencies of Th17 cells (1.47 ± 0.87%) and the number of neutrophils (7.4 ± 4.1 × 10(9) /L) in peripheral blood samples from children infected with EV71 were significantly higher compared to controls. In addition, there was a statistically higher expression of ROR γt in peripheral blood mononuclear cells (PBMCs) and elevated concentrations of IL-17 and IL-23 in sera, but lower IFN-γ production during EV71 infections. The findings suggest that Th17 cells are mediators during the immunologic process.