Interleukin-20 antibody is a potential therapeutic agent for experimental arthritis

The effect of interleukin-20 on periodontal tissue destruction in individuals with periodontitis

BACKGROUND AND OBJECTIVE

Periodontitis is an inflammatory disease that destroys periodontal tissues. Interleukin-20 (IL-20), on the other hand, is known as a potent angiogenic, chemotactic, and pro-inflammatory cytokine associated with various chronic inflammatory disorders. IL-20 has a significant role in the regulation of osteoclastogenesis and osteoblastogenesis. This study aimed to evaluate the effect of IL-20 on periodontal destruction.

METHODS

In this study, a total of 60 participants were included, 30 of whom were systemically and periodontally healthy (control group), and 30 were systemically healthy but had periodontitis (periodontitis group). Gingival crevicular fluid (GCF) and serum samples were collected from the participants for biochemical analysis. Enzyme-linked immunosorbent assay was used to determine the levels of IL-20, tumor necrosis factor (TNF)-α, IL1β/IL-10, RANKL/osteoprotegerin (OPG), and matrix metalloproteinase-8 (MMP8). For statistical analysis, the independent t-test, Pearson correlation coefficients, and the Chi-square test were used.

RESULTS

GCF IL-20, RANKL, RANKL/OPG, serum IL-20, RANKL, RANKL/OPG, MMP-8, TNF-α, IL-1B, and IL-1β/IL-10 values were found to be statistically significantly higher in the periodontitis group than in the control group. GCF OPG and serum IL-10 values were found to be statistically significantly higher in the control group than in the periodontitis group. No statistically significant difference was observed between the groups in serum OPG values. A statistically significantly positive correlation was observed between serum IL-20 value and serum RANKL, RANKL/OPG, MMP-8, TNF-α, IL-1β values, and periodontal clinical parameters. The ROC curves showed: AUC = 0.788 for GCF IL-20, and AUC = 1.000 for serum IL-20.

CONCLUSION

According to the results of the study, IL-20 was found to be associated with periodontitis. The role of IL-20 in periodontal pathogenesis is related to osteoclastogenesis and collagen degradation. It is conceivable that IL-20 may increase bone destruction by both affecting the RANKL/OPG ratio and proinflammatory cytokines.

Immunomodulatory Effect of Hypericin-Mediated Photodynamic Therapy on Oral Cancer Cells

In 2020, there were 377,713 new oral and lip cancer diagnoses and 177,757 deaths. Oral cancer is a malignancy of the head and neck region, and 90% of cases are squamous cell carcinomas (OSCCs). One of the alternative methods of treating pre-cancerous lesions and oral cancer is photodynamic therapy (PDT). In addition to the cytotoxic effect, an important mechanism of PDT action is the immunomodulatory effect. This study used the OSCC (SCC-25) cell line and the healthy gingival fibroblast (HGF-1) line. A compound of natural origin-hypericin (HY)-was used as the photosensitizer (PS). The HY concentrations of 0-1 µM were used. After two hours of incubation with PS, the cells were irradiated with light doses of 0-20 J/cm2. The MTT test determined sublethal doses of PDT. Cell supernatants subjected to sublethal PDT were assessed for interleukin 6 (IL-6), soluble IL-6 receptor alpha (sIL-6Ralfa), sIL-6Rbeta, IL-8, IL-10, IL-11 IL-20, IL-32, and Pentraxin-3 using the Bio-Plex ProTM Assay. The phototoxic effect was observed starting with a light dose of 5 J/cm2 and amplified with increasing HY concentration and a light dose. HY-PDT affected the SCC-25 cell secretion of sIL-6Rbeta, IL-20, and Pentraxin-3. HY alone increased IL-8 secretion. In the case of HGF-1, the effect of HY-PDT on the secretion of IL-8 and IL-32 was found.

Nonalcoholic fatty liver disease in inflammatory arthritis: Relationship with cardiovascular risk

Liver disease is one of the most important causes of morbidity and mortality worldwide whose prevalence is dramatically increasing. The first sign of hepatic damage is inflammation which could be accompanied by the accumulation of fat called non-alcoholic fatty liver disease (NAFLD), causing damage in the hepatocytes. This stage can progress to fibrosis where the accumulation of fibrotic tissue replaces healthy tissue reducing liver function. The next stage is cirrhosis, a late phase of fibrosis where a high percentage of liver tissue has been replaced by fibrotic tissue and liver functionality is substantially impaired. There is a close interplay of cardiovascular disease (CVD) and hepatic alterations, where different mechanisms mediating this relation between the liver and systemic vasculature have been described. In chronic inflammatory diseases such as rheumatoid arthritis (RA) and psoriatic arthritis (PsA), in which the CVD risk is high, hepatic alterations seem to be more prevalent compared to the general population and other rheumatic disorders. The pathogenic mechanisms involved in the development of this comorbidity are still unraveled, although chronic inflammation, autoimmunity, treatments, and metabolic deregulation seem to have an important role. In this review, we will discuss the involvement of liver disease in the cardiovascular risk associated with inflammatory arthritis, the pathogenic mechanisms, and the recognized factors involved. Likewise, monitoring of the liver disease risk in routine clinical practice through both, classical and novel techniques and indexes will be exposed. Finally, we will examine the latest controversies that have been raised about the effects of the current therapies used to control the inflammation in RA and PsA, in the liver damage of those patients, such as methotrexate, leflunomide or biologics.

Increased expression of IL-20 is associated with ischemic cardiomyopathy and acute myocardial infarction

Background: The expression and clinical significance of IL-20 in coronary artery diseases needs to be analyzed. Methods: IL-20 and its receptors were analyzed in coronary artery tissues. In a separate study, plasma IL-20 was also evaluated. Results: IL-20 and its receptors were significantly higher in coronary artery stenosis tissues from ischemic cardiomyopathy patients than that from controls. T lymphocytes and macrophages were the main source of IL-20 and expressed its receptors abundantly. Plasma IL-20 was significantly higher in acute myocardial infarction patients than that in controls. Conclusion: IL-20 was closely associated with the presence of acute myocardial infarction. IL-20 may participate in the progression of coronary artery stenosis and plaque vulnerability via regulating T lymphocytes and macrophages.

Expression of IL-20 Receptor Subunit β Is Linked to EAE Neuropathology and CNS Neuroinflammation

Considerable clinical evidence supports that increased blood-brain barrier (BBB) permeability is linked to immune extravasation of CNS parenchyma during neuroinflammation. Although BBB permeability and immune extravasation are known to be provoked by vascular endothelial growth factor-A (i.e., VEGF-A) and C-X-C motif chemokine ligand 12 (CXCL12), respectively, the mechanisms that link both processes are still elusive. The interleukin-20 (i.e., IL-20) cytokine signaling pathway was previously implicated in VEGF-mediated angiogenesis and is known to induce cellular response by way of signaling through IL-20 receptor subunit β (i.e., IL-20RB). Dysregulated IL-20 signaling is implicated in many inflammatory pathologies, but it's contribution to neuroinflammation has yet to be reported. We hypothesize that the IL-20 cytokine, and the IL cytokine subfamily more broadly, play a key role in CNS neuroinflammation by signaling through IL-20RB, induce VEGF activity, and enhance both BBB-permeability and CXCL12-mediated immune extravasation. To address this hypothesis, we actively immunized IL-20RB^-/- mice and wild-type mice to induce experimental autoimmune encephalomyelitis (EAE) and found that IL-20RB^-/- mice showed amelioration of disease progression compared to wild-type mice. Similarly, we passively immunized IL-20RB^-/- mice and wild-type mice with myelin-reactive Th1 cells from either IL-20RB^-/- and wild-type genotype. Host IL-20RB^-/- mice showed lesser disease progression than wild-type mice, regardless of the myelin-reactive Th1 cells genotype. Using multianalyte bead-based immunoassay and ELISA, we found distinctive changes in levels of pro-inflammatory cytokines between IL-20RB^-/- mice and wild-type mice at peak of EAE. We also found detectable levels of all cytokines of the IL-20 subfamily within CNS tissues and specific alteration to IL-20 subfamily cytokines IL-19, IL-20, and IL-24, expression levels. Immunolabeling of CNS region-specific microvessels confirmed IL-20RB protein at the spinal cord microvasculature and upregulation during EAE. Microvessels isolated from macaques CNS tissues also expressed IL-20RB. Moreover, we identified the expression of all IL-20 receptor subunits: IL-22 receptor subunit α-1 (IL-22RA1), IL-20RB, and IL-20 receptor subunit α (IL-20RA) in human CNS microvessels. Notably, human cerebral microvasculature endothelial cells (HCMEC/D3) treated with IL-1β showed augmented expression of the IL-20 receptor. Lastly, IL-20-treated HCMEC/D3 showed alterations on CXCL12 apicobasal polarity consistent with a neuroinflammatory status. This evidence suggests that IL-20 subfamily cytokines may signal at the BBB via IL-20RB, triggering neuroinflammation.

Management of SARS-CoV-2 Infection: Key Focus in Macrolides Efficacy for COVID-19

Macrolides (e.g., erythromycin, fidaxomicin, clarithromycin, and azithromycin) are a class of bacteriostatic antibiotics commonly employed in medicine against various gram-positive and atypical bacterial species mostly related to respiratory tract infections, besides they possess anti-inflammatory and immunomodulatory effects. Coronavirus Disease 2019 (COVID-19) is an infectious disease caused by the severe acute respiratory syndrome of coronavirus 2 (SARS-CoV-2). It was first detected in Wuhan, Hubei, China, in December 2019 and resulted in a continuing pandemic. Macrolides have been extensively researched as broad adjunctive therapy for COVID-19 due to its immunostimulant abilities. Among such class of drugs, azithromycin is described as azalide and is well-known for its ability to decrease the production of pro-inflammatory cytokines, including matrix metalloproteinases, tumor necrosis factor-alpha, interleukin (IL)-6, and IL-8. In fact, a report recently published highlighted the effectiveness of combining azithromycin and hydroxychloroquine for COVID-19 treatment. Indeed, it has been underlined that azithromycin quickly prevents SARS-CoV-2 infection by raising the levels of both interferons and interferon-stimulated proteins at the same time which reduces the virus replication and release. In this sense, the current review aims to evaluate the applications of macrolides for the treatment of COVID-19.

The expression of interleukin 20 increases in plasma and aortic tissues from patients with acute aortic dissection

OBJECTIVE

Acute aortic dissection (AAD) is the most devasting cardiovascular disease associated with high mortality. The occurrence and progression of AAD can be regulated by inflammatory processes, and further understanding of this inflammatory pathogenesis may improve the treatment of AAD. Interleukin 20 (IL-20), as an inflammatory mediator, has been demonstrated to be associated with several inflammatory diseases. However, the association between IL and 20 and AAD is still unknown.

METHODS

Five aortic dissection tissue samples and five control aortic tissue samples were evaluated in our study. The expression of IL-20 and its receptor subunits (IL-20Rα and IL-20Rβ) was detected by immunofluorescence staining. From January 2018 to March 2018, 70 consecutive AAD patients and 25 non-AAD (NAD) patients were enrolled in this study. Diagnosis was based on computed tomography angiography (CTA) results. Blood samples were obtained from the patients on the first day of hospitalization. Plasma IL-20, TNF-α and IL-6 concentrations were evaluated with enzyme-linked immunosorbent assay (ELISA) kits.

RESULTS

The expression levels of IL-20 and its receptor subunits (IL-20Rα and IL-20Rβ) were increased in the sites of arterial wall dissection in the AAD patients. In a separate group, the plasma IL-20, TNF-α and IL-6 concentrations were significantly higher in the AAD patients than in the non-AAD patients. Spearman's correlation analysis showed that plasma IL-20 was positively correlated with plasma TNF-α and IL-6, D-dimer, C-reaction protein (CRP), creatinine, fasting blood glucose, systolic blood pressure (SBP), and diastolic blood pressure (DBP). Multiple linear regression revealed that IL-20, in addition to IL-6, glucose, CRP and D-dimer, was independently associated with the presence of AAD.

CONCLUSION

IL-20 was closely associated with the presence of AAD. IL-20 may contribute to the inflammatory pathogenesis of AAD.

Interleukin-18, interleukin-20, and matrix metalloproteinases (MMP-1, MMP-3) as markers of psoriatic arthritis disease severity and their correlations with biomarkers of inflammation and turnover of joint cartilage

Introduction

Psoriatic arthritis (PsA) is a chronic, seronegative spondyloarthropathy characterised by joint inflammation and psoriatic skin changes. Recent data indicate that interleukin-18 (IL-18) and interleukin-20 (IL-20) may be involved in the aetiopathogenesis of PsA.

Aim

To evaluate the potential role of IL-18, IL-20, and matrix metalloproteinases (MMP-1, MMP-3) in the pathogenesis of PsA and their correlations with other markers of inflammation and destruction of joint cartilage, as well as clinical changes.

Material and methods

The study included 24 patients with PsA and 26 healthy volunteers as a control group. The concentration of IL-18 and IL-20, c-reactive protein (CRP), metalloproteinase-1 and -3 (MMP-1, MMP-3), cartilage oligomeric matrix protein (COMP), aggrecan (PG-AG), and human cartilage glycoprotein (YKL-40) in serum was determined. Clinical severity of the disease according to the BSA, PASI, and DLQI as well as tender and swollen joint count (TJC, SJC) were also evaluated.

Results

The concentration of IL-18 was statistically significantly higher in the serum of patients with PsA than in the control group (62.87 pg/ml vs. 16.73 pg/ml, p < 0.0049). Serum IL-20 levels in PsA patients were also higher than in the control group, but without statistical significance (p = 0.2939). The ROC curves showed: AUC = 0.81 for IL-18, AUC = 0.75 for IL-20, AUC = 0.96 for COMP, and AUC = 0.89 for MMP-3.

Conclusions

IL-18 and IL-20 as well as MMP-3 and COMP may be sensitive markers in the diagnosis of PsA.

IL-20 in Acute Kidney Injury: Role in Pathogenesis and Potential as a Therapeutic Target

Acute kidney injury (AKI) causes over 1 million deaths worldwide every year. AKI is now recognized as a major risk factor in the development and progression of chronic kidney disease (CKD). Diabetes is the main cause of CKD as well. Renal fibrosis and inflammation are hallmarks in kidney diseases. Various cytokines contribute to the progression of renal diseases; thus, many drugs that specifically block cytokine function are designed for disease amelioration. Numerous studies showed IL-20 functions as a pro-inflammatory mediator to regulate cytokine expression in several inflammation-mediated diseases. In this review, we will outline the effects of pro-inflammatory cytokines in the pathogenesis of AKI and CKD. We also discuss the role of IL-20 in kidney diseases and provide a potential therapeutic approach of IL-20 blockade for treating renal diseases.

IL-10 Family Cytokines IL-10 and IL-22: from Basic Science to Clinical Translation

Cytokines are among the most important effector and messenger molecules in the immune system. They profoundly participate in immune responses during infection and inflammation, protecting against or contributing to diseases such as allergy, autoimmunity, and cancer. Manipulating cytokine pathways, therefore, is one of the most effective strategies to treat various diseases. IL-10 family cytokines exert essential functions to maintain tissue homeostasis during infection and inflammation through restriction of excessive inflammatory responses, upregulation of innate immunity, and promotion of tissue repairing mechanisms. Their important functions in diseases are supported by data from many preclinical models, human genetic studies, and clinical interventions. Despite significant efforts, however, there is still no clinically approved therapy through manipulating IL-10 family cytokines. Here, we summarize the recent progress in understanding the biology of this family of cytokines, suggesting more specific strategies to maneuver these cytokines for the effective treatment of inflammatory diseases and cancers.

Ibudilast Inhibits Chemokine Expression in Rheumatoid Arthritis Synovial Fibroblasts and Exhibits Immunomodulatory Activity in Experimental Arthritis

OBJECTIVE

Ibudilast is a well-tolerated, orally available phosphodiesterase 4 (PDE4) inhibitor used to treat asthma and stroke. Since PDE4 inhibition suppresses inflammatory mediator production and cell proliferation in leukocytes, ibudilast may be a valuable therapy for the treatment of inflammatory autoimmune diseases such as rheumatoid arthritis (RA). This study was undertaken to assess the therapeutic potential of ibudilast by measuring its capacity to modulate inflammation in human leukocytes and RA synovial fibroblasts (RASFs) and in experimental arthritis.

METHODS

Using standard curve quantitative polymerase chain reaction, the effect of ibudilast on gene expression in activated human leukocytes and RASFs was measured. Ibudilast was used to treat DBA/1 mice with collagen-induced arthritis, and an adoptive transfer model was used to assess its tolerogenic capacity.

RESULTS

Ibudilast inhibited the expression of TNF, IL12A, and IL12B and the secretion of tumor necrosis factor (TNF) and interleukin-12 (IL-12)/23p40 from leukocytes, and reduced the expression of CCL5 and CCL3 in activated RASFs. Treatment of experimental arthritis with ibudilast resulted in a reduction in IL-17-producing cells and inhibition of disease progression. When combined with a TNF inhibitor, ibudilast caused marked suppression of active disease. Exposure of leukocytes from type II collagen-immunized DBA/1 mice to ibudilast in vitro attenuated their ability to adoptively transfer arthritis to DBA/1J-Prkdc^SCID mice, providing evidence of an immunomodulatory effect.

CONCLUSION

Our findings indicate that ibudilast reduces the expression and/or secretion of inflammatory mediators from activated human leukocytes and RASFs, inhibits Th17 cell responses in vivo, and improves established arthritis. Given the established safety profile of ibudilast in humans, its clinical evaluation in RA, either alone or in combination with a TNF inhibitor, should be considered.

Correlation Between IL-20 and De Quervain's Disease Severity

De Quervain's disease is a stenosing tenosynovitis of the first dorsal compartment of the wrist. Histopathological studies have reported that the thickening of the first dorsal retinaculum is characterized by degeneration rather than inflammation. However, significant infiltration of mast cells and macrophages was noted in a torn tendon study, which suggested that innate immune pathways are part of the mechanism that mediates early tendinopathy. Recently, Interleukin-20 (IL-20) has been reported to provoke potent inflammation and regulate angiogenesis and chemotaxis, which are important for the pathogenesis of inflammatory diseases. The main purpose of our study was to investigate the correlation between IL-20 and tumor necrosis factor (TNF-α) and clarify the potential predictor of tendinopathy progression. Hematoxylin and eosin (H & E) and immunohistochemistry (IHC) staining were used to score and analyze the clinical outcome. TNF-α, IL-20 and related inflammation cytokines were examined. Moreover, the tenocytes were cultured with a stimulator and were used to examine inflammatory cytokine secretions. A real-time polymerase chain reaction (Real-time PCR) was used to detect the gene expression profile. The IHC data showed that TNF-α is up-regulated in grade III de Quervain's. The analysis data showed that IL-20 is positively correlated with TNF-α and disease severity. The real-time PCR showed that the inflammation stimulator enhanced the expression of IL-20 mRNA expression. Inflammation cytokines such as TNF-alpha, transforming growth factor-β (TGF-β) and IL-1 have been used as predictors of de Quervain's; IL-20 is a new predictor based on this study. In the future, IL-20 expression's involvement in the molecular mechanism of the severity of de Quervain's should be further investigated.

IL-20 receptor cytokines in autoimmune diseases

IL-19, IL-20, and IL-24 are the members of IL-10 family. They are also known as IL-20 receptor (IL-20R) cytokines as they all signal through the IL-20RA/IL-20RB receptor complex; IL-20 and IL-24 (but not IL-19) also signal through the IL-20RB/IL22RA1 receptor complex. Despite their protein structure homology and shared use of receptor complexes, they display distinct biological functions in immune regulation, tissue homeostasis, host defense, and oncogenesis. IL-20R cytokines can be expressed by both immune cells and epithelial cells, and are important for their interaction. In general, these cytokines are considered to be associated with pathogenesis of chronic inflammation and autoimmune diseases, including psoriasis, rheumatoid arthritis, and inflammatory bowel disease. However, a number of studies also highlighted their suppressive functions in regulating both innate and adaptive T cell responses and other immune cells, suggesting that the role of IL-20R cytokines in autoimmunity may be complex. In this review, we will discuss the immunobiological functions of IL-20R cytokines and how they are involved in regulating autoimmune diseases.

Potential therapeutic antibodies targeting specific adiponectin isoforms in rheumatoid arthritis

Background

Different adiponectin isoforms appear to be differentially involved in the pathogenesis of various diseases. The purpose of this study was to generate monoclonal antibodies (mAbs) specific to different adiponectin isoforms and investigate whether these mAbs have potential as therapeutic agents for such diseases.

Methods

Hybridoma cells producing monoclonal antibodies were generated and screened using enzyme-linked immunosorbent assay and Western blotting for the production of mAbs recognizing human adiponectin isoforms.

Results

The mAb from hybridoma clone KH7–41 recognized both the middle molecular weight (MMW) (hexamer) and low molecular weight (LMW) (trimer) isoforms of adiponectin in human serum, whereas the KH7–33 mAb detected only MMW (hexamer) adiponectin. The KH4–8 clone recognized both the high molecular weight (HMW) (multimer) and MMW adiponectin isoforms. However, in mouse and rat sera, the abovementioned antibodies recognized only the MMW isomer. These mAbs also recognized adiponectin in various human tissues, such as lung, kidney, and adipose tissues, although the three mAbs had different staining intensities. The mAb from clone KH4–8 effectively inhibited increases in interleukin-6 (IL-6) and IL-8 expression in recombinant adiponectin-stimulated human osteoblasts and human umbilical vein endothelial cells. Also, the mAbs KH7–33 and KH4–8 significantly ameliorated rheumatic symptoms in a collagen-induced arthritis mouse model. This result suggests that these mAb treatments may ameliorate adiponectin-mediated inflammatory response.

Conclusions

mAbs against human adiponectin isomers can potentially be developed as therapeutic antibodies to target specific detrimental isoforms of adiponectin while maintaining the functions of beneficial isoforms.

Electronic supplementary material

The online version of this article (10.1186/s13075-018-1736-3) contains supplementary material, which is available to authorized users.

The roles of IL-19 and IL-20 in the inflammation of degenerative lumbar spondylolisthesis

Background

Degenerative lumbar spondylolisthesis (DLS) is a major cause of spinal canal stenosis and is often related to lower back pain. IL-20 is emerging as a potent angiogenic, chemotactic, and proinflammatory cytokine related to several chronic inflammatory bone disorders likes intervertebral disc herniation, rheumatoid arthritis (RA), osteoporosis, and bone fracture. IL-19 also acts as a proinflammatory cytokine in RA. The aim of the present study was to investigate whether IL-19 and IL-20 are involved in DLS and compare three different tissues including disc, facet joint, and ligamentum flavum of patients with DLS to verify which tissue is affected more by inflammation.

Methods

Disc, facet joint and ligamentum flavum from 13 patients with DLS was retrieved, and the expression pattern of IL-19, IL-20, IL-20R1, IL-20R2, TNF-α, IL-1β, and MCP-1 was evaluated using immunohistochemical staining with specific antibodies. The disc cells were isolated and incubated with IL-19 and IL-20 under CoCl₂-mimicked hypoxic conditions to analyze the proinflammatory cytokine expression pattern using real-time quantitative PCR with specific primers.

Results

IL-19 and IL-20 were positively stained and accompanied by abundant expression of TNF-α, IL-1β, and MCP-1 in facet joints of DLS patients. IL-19 and IL-20's receptors (IL-20R1 and IL-20R2) were expressed on chondrocytes and fibrocytes/fibroblasts in facet joint and ligamentum flavum tissues from patients with DLS. There was a significant correlation between the expression of IL-20 and IL-1β in facet joint. In vitro assay, IL-19 and IL-20 upregulated the expression of IL-1β, IL-6, TNF-α, IL-8, VEGF, and MCP-1 in primary cultured DLS disc cells under CoCl₂-mimicked hypoxic conditions.

Conclusions

IL-19, IL-20, and their receptors as well as proinflammatory cytokines (TNF-α, IL-1β, and MCP-1) were expressed more in facet joints than the other tissues in patients with DLS; therefore, the etiology of inflammation might be more facet-centric. IL-19 and IL-20 induced proinflammatory cytokine expression in disc cells and might play a role in the pathogenesis of DLS.

Trivalent soluble TNF Receptor, a potent TNF-α antagonist for the treatment collagen-induced arthritis

Tumor necrosis factor is a major pro-inflammatory cytokine which triggers various physiological consequences by binding to and trimerizing its receptors, and has been the single most sought-after drug target for intervening autoimmune diseases such as rheumatoid arthritis and psoriasis. However, current TNF-α blockers, including soluble receptor-Fc fusion and therapeutic antibodies, are all dimeric in structure, whereas their target TNF-α itself is homotrimeric in nature. Here we describe the development of a trivalent soluble TNF receptor and show that it is a more potent than the dimeric TNF receptor decoys in inhibiting TNF-α signaling both in vitro and in vivo. The process involves gene fusion between a soluble receptor TNFRII with a ligand binding domain and a trimerization tag from the C-propeptide of human collagen (Trimer-Tag), which is capable of self-assembly into a covalently linked trimer. We show that the homotrimeric soluble TNF receptor (TNFRII-Trimer) produced with such method is more potent in ligand binding kinetics and cell based bioassays, as well as more efficacious in attenuating collagen-induced arthritis (CIA) in a mouse model than its dimeric TNFRII-Fc counterpart. Thus, this work demonstrates the proof of concept of Trimer-Tag and provides a new platform for rational designs of next generation biologic drugs.

IL-20 bone diseases involvement and therapeutic target potential

BACKGROUND

Millions of people around the world suffer from bone disorders, likes osteoporosis, rheumatoid arthritis (RA), and cancer-induced osteolysis. In general, the bone remodeling balance is determined by osteoclasts and osteoblasts, respectively responsible for bone resorption and bone formation. Excessive inflammation disturbs the activities of these two kinds of cells, typically resulting in the bone loss.

MAIN BODY

IL-20 is emerging as a potent angiogenic, chemotactic, and proinflammatory cytokine related to several chronic inflammatory disorders likes psoriasis, atherosclerosis, cancer, liver fibrosis, and RA. IL-20 has an important role in the regulation of osteoclastogenesis and osteoblastogenesis and is upregulated in several bone-related diseases. The anti-IL-20 monoclonal antibody treatment has a therapeutic potential in several experimental disease models including ovariectomy-induced osteoporosis, cancer-induced osteolysis, and bone fracture.

CONCLUSION

This review article provides an overview describing the IL-20's biological functions in the common bone disorders and thus providing a novel therapeutic strategy in the future.

The IL20 Genetic Polymorphism Is Associated with Altered Clinical Outcome in Septic Shock

BACKGROUND

The IL10 family of genes includes crucial immune regulators. We tested the hypothesis that single nucleotide polymorphisms (SNPs) in IL10, IL19, IL20, and IL24 of the IL10 family gene cluster alter the clinical outcome of septic shock.

METHODS

Patients with septic shock (n = 1,193) were genotyped for 13 tag SNPs of IL10, IL19, IL20, and IL24. IL20 gene expression was measured in genotyped lymphoblastoid cells in vitro. Cardiac surgical ICU patients (n = 981) were genotyped for IL20 rs2981573 A/G. The primary outcome variable was 28-day mortality.

RESULTS

Patients with the G allele of IL20 rs2981573 had a significantly increased hazard of death over the 28-day period compared to patients with the A allele in the septic shock cohort (adjusted hazard ratio 1.27; 95% confidence interval 1.10-1.47; p = 8.0 × 10-4). Patients with the GG genotype had more organ dysfunction (p < 0.05). The GG genotype was associated with increased IL20 gene expression in stimulated lymphoblastoid cells in vitro (p < 0.05). The cardiac surgical ICU patients with the GG genotype had an increased length of ICU stay (p = 0.032).

CONCLUSIONS

The GG genotype of IL20 rs2981573 SNP was associated with increased IL20 gene expression and increased adverse outcomes in patients with septic shock and following cardiac surgery.

Hierarchical, imbalanced pro-inflammatory cytokine networks govern the pathogenesis of chronic arthropathies

BACKGROUND

Chronic inflammatory arthropathies, such as rheumatoid arthritis (RA), spondyloarthritis, including psoriatic arthritis (PsA), ankylosing spondyloarthritis (AS), osteoarthritis (OA), and intervertebral disc degenerative disease (DDD) constitute major public health problems that are anticipated to grow significantly as the human population ages. However, many aspects concerning the molecular mechanisms underlying their onset and progression remain unclear.

DESIGN

This narrative review critically analyzes the molecular mechanisms underlying the inflammation-associated pathogenesis of the aforementioned joint diseases. This includes, in particular, the major role played by several key soluble factors (such as cytokines and the associated signaling pathways, designated as "fragile nodes") produced by local cells and recruited to the joints' immune cells, whose elimination by specific drugs has dramatically improved the diseases' symptomatology and outcome in human clinical trials or in rodent arthritis models.

HYPOTHESIS AND THE AIM OF THIS REVIEW

We hypothesize that the pathogenesis of chronic inflammatory arthropathies is governed by hierarchical, imbalanced pro-inflammatory cytokine networks (HIPICNs) (comprising a combination of fragile nodes) that are created during the development of both autoimmune (RA, PsA, and AS) and non-autoimmune (OA and DDD) disorders. The main aim of this review is to provide evidence that despite substantial pathobiological differences between these arthropathies, the HIPICNs created are quite common, thus justifying the merging of these disorders mechanistically and suggesting that these common mechanisms exist in the onset and progression of different joint diseases.

Suppression and resolution of autoimmune arthritis by rhesus θ-defensin-1, an immunomodulatory macrocyclic peptide

θ-defensins constitute a family of macrocyclic peptides expressed exclusively in Old World monkeys. The peptides are pleiotropic effectors of innate immunity, possessing broad spectrum antimicrobial activities and immunoregulatory properties. Here we report that rhesus θ-defensin 1 (RTD-1) is highly effective in arresting and reversing joint disease in a rodent model of rheumatoid arthritis (RA). Parenteral RTD-1 treatment of DA/OlaHsd rats with established pristane-induced arthritis (PIA) rapidly suppressed joint disease progression, restored limb mobility, and preserved normal joint architecture. RTD-1 significantly reduced joint IL-1β levels compared with controls. RTD-1 dose-dependently inhibited fibroblast-like synoviocyte (FLS) invasiveness and FLS IL-6 production. Consistent with the inhibition of FLS invasiveness, RTD-1 was a potent inhibitor of arthritogenic proteases including ADAMs 17 and 10 which activate TNFα, and inhibited matrix metalloproteases, and cathepsin K. RTD-1 was non-toxic, non-immunogenic, and effective when administered as infrequently as once every five days. Thus θ-defensins, which are absent in humans, have potential as retroevolutionary biologics for the treatment of RA.

Interleukin-20 is triggered by TLR ligands and associates with disease activity in patients with rheumatoid arthritis

BACKGROUND

Interleukin (IL)-20 is a pro-inflammatory cytokine that may be implicated in the pathogenesis of rheumatoid arthritis (RA). This study aimed to determine the association between IL-20 and disease activity in patients with RA.

METHODS

The levels of serum and synovial fluid IL-20 were measured in patients with RA and OA. The disease activity was assessed based on the Disease Activity Score of 28 joints (DAS28). The expression of IL-20 in synovial tissue samples from patients with RA and OA were determined by immunohistochemistry. Immunofluorescence staining was used to co-localize IL-20 with selected cells. The secretion of IL-20 was analysed in human peripheral blood mononuclear cells (PBMCs) of patients with RA.

RESULTS

Synovial fluid and synovial tissue IL-20 were significantly increased in patients with RA compared with patients with OA. The expression of IL-20 in RA synovial tissue was particularly associated with macrophages and neutrophil granulocytes, but also with synovial fibroblasts and lymphocytes. The IL-20 levels in synovial fluid correlated with DAS28 (r=0.434; p=0.015) and were significantly elevated in anti-CCP positive RA compared with anti-CCP negative RA (122.3±104.1pg/ml and 45.9±35.8pg/ml; p=0.008). IL-20 production from PBMCs was induced by Poly I:C and LPS but not with pro-inflammatory cytokines, such as TNF-α or IL-1.

CONCLUSION

Our data showed that IL-20 is independently associated with RA disease activity and may be triggered by TLR ligands at local sites of inflammation.

Anti-IL-20 monoclonal antibody inhibited inflammation and protected against cartilage destruction in murine models of osteoarthritis

Osteoarthritis (OA) is a degenerative joint disease characterized by progressive destruction of articular cartilage. Interleukin (IL)-20 is a proinflammatory cytokine involved in the pathogenesis of rheumatoid arthritis. We investigated the role of IL-20 in OA and evaluated whether anti-IL-20 antibody (7E) treatment attenuates disease severity in murine models of surgery-induced OA. Immunohistochemical staining was used to detect IL-20 and its receptors expression in synovial tissue and cartilage from OA patients, and in OA synovial fibroblasts (OASFs) and chondrocytes (OACCs) from rodents with surgery-induced OA. RTQ-PCR and western blotting were used to determine IL-20-regulated OA-associated gene expression in OASFs and OACCs. OA rats and OA mice were treated with 7E. Arthritis severity was determined based on the degree of cartilage damage and the arthritis severity score. We found that IL-20 and its receptors were expressed in OASFs and OACCs. IL-20 induced TNF-α, IL-1β, MMP-1, and MMP-13 expression by activating ERK-1/2 and JNK signals in OASFs. IL-20 not only upregulated MCP-1, IL-6, MMP-1, and MMP-13 expression, but also downregulated aggrecan, type 2 collagen, TGF-β, and BMP-2 expression in OACCs. Arthritis severity was significantly lower in 7E-treated OA rats, and 7E- or MSC-treated OA mice. Therefore, we concluded that IL-20 was involved in the progression and development of OA through inducing proinflammatory cytokines and OA-associated gene expression in OASFs and OACCs. 7E reduced the severity of arthritis in murine models of surgery-induced OA. Our findings provide evidence that IL-20 is a novel target and that 7E is a potential therapeutic agent for OA.

A Broad Blockade of Signaling from the IL-20 Family of Cytokines Potently Attenuates Collagen-Induced Arthritis

Two heterodimeric receptors consisting of either IL-20R1 or IL-22R1 in complex with a common β receptor subunit IL-20R2 are shared by three of the IL-20 family of cytokines: IL-19, IL-20, and IL-24. These proinflammatory cytokines have been implicated in the pathogenesis of some autoimmune diseases, including rheumatoid arthritis (RA), psoriasis, and atopic dermatitis. Although mAbs against IL-19 and IL-20 have each been shown to modulate disease severity of collagen-induced arthritis in animal models, and anti-IL-20 therapeutic Ab has exhibited some efficacy in the treatment of RA in clinical trials, benefits for a complete blockade of these functionally redundant cytokines remain to be explored. In this report, we show that recombinant human soluble IL-20R2-Fc fusion protein binds to IL-19, IL-20, and IL-24 with similar high affinity and blocks their signaling in vitro. In DBA/1 mouse collagen-induced arthritis model, recombinant human IL-20R2-Fc exhibits comparable efficacy as TNF blocker etanercept in the treatment of established arthritis, whereas the combined use of both biologics manifests little synergistic therapeutic effects. In situ ligand-receptor functional binding analysis shows that a large amount of immune infiltrates expressing high levels of TNFR and IL-20 subfamily cytokines congregate within the inflamed disease tissues. Colocalization experiments reveal that signals from IL-20R2 and TNF transduction pathways seem to converge in macrophages and function in tandem in orchestrating the pathogenesis of RA. Elucidation of this interaction provides a better understanding of cytokine cross-talk in RA and a rationale for more effective biologic therapies that target IL-20R2 instead of individual cytokines from IL-20 family.

The IL-20 receptor axis in immune-mediated inflammatory arthritis: novel links between innate immune recognition and bone homeostasis

The treatment of rheumatoid arthritis (RA) and spondyloarthritis (SpA) was transformed a little over a decade ago by the introduction of agents neutralizing the pro-inflammatory cytokine tumour necrosis factor (TNF)-α. Nevertheless, some patients do not achieve remission and the inhibition of the normal immune system with current drugs increases the risk of infection. The interleukin (IL)-20 receptor (IL-20R) axis is pivotal for tissue homeostasis. By contrast, this axis does not seem to directly activate cells of the immune system. Thus, modulation of the IL-20R axis might not result in increased risk of infection. The IL-20R axis consists of the three cytokines IL-19, IL-20, and IL-24 (termed the IL-20R cytokines) and their shared receptors. All three cytokines bind the receptor complex of IL-20R2/IL-20R1 whereas only IL-20 and IL-24 also bind the receptor complex of IL-20R2/IL-22R1. This short review describes how the IL-20R axis could be a novel link between innate immune recognition and bone homeostasis. The IL-20R cytokines are produced in response to both danger-associated molecular patterns and immune complexes formed by RA-associated autoantibodies. This could be of importance because these mediators can thus be present even in situations without inflammation. IL-19 shows anti-inflammatory properties in arthritis through IL-20R1. IL-20 and IL-24 through IL-22R seem to participate in the recruitment of mononuclear cells to the synovial joint and to sites of bone erosion in particular. Our results indicate that dual inhibition of IL-20 and IL-24 or attenuation of the shared IL-22R subunit could have a beneficial effect on radiographic progression, especially in seropositive RA.

Possibilities for preventive treatment in rheumatoid arthritis? Lessons from experimental animal models of arthritis: a systematic literature review and meta-analysis

OBJECTIVE

Current research in rheumatoid arthritis focuses on preclinical disease phases as it is hypothesised that early preclinical treatment might prevent progression to full-blown disease. Since performance of studies in prearthritis phases in humans is challenging, animal models offer an opportunity to evaluate preventive treatments. We performed a systematic literature review and summarised treatment effects during different stages of arthritis development in animal models.

METHODS

Eight medical literature databases were systematically searched. Studies were selected if they reported effects of synthetic or biological disease-modifying antirheumatic drugs in animal models of arthritis (collagen-induced arthritis and adjuvant-induced arthritis) on arthritis severity, as measured with arthritis severity scores, paw swelling or paw volume. Quality was assessed using an 11-item checklist. Study characteristics were extracted and effect sizes obtained in high-quality studies were summarised in meta-analyses. Studies were categorised into three groups: prophylactic (prior to generation of autoantibody response), prearthritis (after induction of autoantibody response) and therapeutic intervention (after arthritis development).

RESULTS

Out of 1415 screened articles, 22 studies (including n=712 animals) were eligible of good quality and included in meta-analyses. Prophylactic (16 experiments, n=312 animals) and prearthritis treatment (9 experiments, n=156 animals) both were associated with a reduction of arthritis severity (p<0.001 and p=0.005, respectively). Stratified analyses for different antirheumatic drugs initiated in the prearthritis phase suggested higher efficacy of methotrexate than of anti-tumour necrosis factor.

CONCLUSIONS

Data of experimental studies in animal models of arthritis suggest that prophylactic and prearthritis treatment strategies are effective and hint at differences in efficacy between antirheumatic drugs.

Emerging Therapies for Rheumatoid Arthritis

Diverse strategies to develop novel treatments for rheumatoid arthritis which specifically target those patients who do not respond to available medications, including biologics, are currently being explored. New potential therapeutic approaches which may become available as part of standard therapeutic regimens include the propagation of regulatory T cells and-in the future-of regulatory B cells. New biologic disease-modifying antirheumatic drugs (b-DMARDs) against interleukin-17 and -6, granulocyte-macrophage colony-stimulating factor, and complement component 5 are now standard components of clinical treatment programs. In addition, recent data indicate that bispecific monoclonal antibody therapies may be more effective than monoclonal antibody monotherapies. It is also becoming apparent that the use of more toxic b-DMARDs against B cells, a therapeutic strategy already being applied in the treatment of hematological diseases, may also be efficacious for treating B cell-mediated autoimmune diseases. Undoubtedly, more small molecules will be developed in the future, and combination therapies with, for example, kinase inhibitors and b-DMARDs, will most likely be tested. Finally, immunoproteasome inhibitors will become available for patients with B cell-mediated autoimmunities, which are refractory to currently available treatment options. The new and exciting extension of current treatment options for rheumatoid arthritis, biosimilars, will not be discussed in this review as details on these agents are available in recently published reports.

Anti-IL-20 monoclonal antibody promotes bone fracture healing through regulating IL-20-mediated osteoblastogenesis

Bone loss and skeletal fragility in bone fracture are caused by an imbalance in bone remodeling. The current challenge in bone fracture healing is to promote osteoblastogenesis and bone formation. We aimed to explore the role of IL-20 in osteoblastogenesis, osteoblast differentiation and bone fracture. Serum IL-20 was significantly correlated with serum sclerostin in patients with bone fracture. In a mouse model, anti-IL-20 monoclonal antibody (mAb) 7E increased bone formation during fracture healing. In vitro, IL-20 inhibited osteoblastogenesis by upregulating sclerostin, and downregulating osterix (OSX), RUNX2, and osteoprotegerin (OPG). IL-20R1 deficiency attenuated IL-20-mediated inhibition of osteoblast differentiation and maturation and reduced the healing time after a bone fracture. We conclude that IL-20 affects bone formation and downregulates osteoblastogenesis by modulating sclerostin, OSX, RUNX2, and OPG on osteoblasts. Our results demonstrated that IL-20 is involved in osteoregulation and anti-IL-20 mAb is a potential therapeutic for treating bone fracture or metabolic bone diseases.

Immunoregulatory Pathways Involved in Inflammatory Bowel Disease

Inflammatory bowel diseases (IBD) include ulcerative colitis and Crohn's disease. The immune response in ulcerative colitis is different from the Crohn's disease. Accumulating evidence suggests that IBD results from an inappropriate inflammatory response to intestinal microbes in a genetically susceptible host. Several immunoregulatory abnormalities have been reported in patients with IBD, including the ratio of proinflammatory (tumor necrosis factor alpha, IL-6, IL-1-β) to immunoregulatory cytokines (IL-10, TGF-β, IL-35) and selective activation of T-helper (Th) lymphocyte subsets (Th1, Th2, Th9, Th17, and regulatory T cells). The purpose of this review is to show the immunoregulatory pathways (regulatory cells and cytokines) involved in IBD published in recent years.

Efficacy and Safety of Anti-Interleukin-20 Monoclonal Antibody in Patients With Rheumatoid Arthritis: A Randomized Phase IIa Trial

OBJECTIVE

Interleukin-20 (IL-20) is implicated in the pathogenesis of rheumatoid arthritis (RA). The efficacy, safety, and tolerability of NNC0109-0012, a selective anti-IL-20 recombinant human monoclonal antibody (mAb), were assessed in patients with active RA who had an inadequate response to methotrexate therapy.

METHODS

Sixty-seven patients with RA were enrolled and randomized (2:1) to receive NNC0109-0012 (3 mg/kg per week, subcutaneously) or placebo in a phase IIa, double-blind, 12-week trial with a 13-week followup. The primary end point was change in the Disease Activity Score in 28 joints based on C-reactive protein level (DAS28-CRP) from baseline to week 12.

RESULTS

In patients treated with NNC0109-0012, the primary end point, improvement in the DAS28-CRP at week 12, was achieved (estimated difference -0.88; P = 0.02), with significant improvement starting at week 1. A greater response was observed in seropositive patients (estimated difference -1.66; P < 0.001), which was sustained through 13 weeks of followup, whereas no improvement was noted in patients with seronegative RA. A significant proportion of patients with seropositive RA receiving NNC0109-0012, compared to those receiving placebo, achieved treatment responses according to the American College of Rheumatology 20% (ACR20) (59% versus 21%), ACR50 (48% versus 14%), and ACR70 (35% versus 0%) levels of improvement, and showed greater improvements in the Health Assessment Questionnaire disability index (P = 0.047). The most frequent adverse events reported with NNC0109-0012 were injection site reactions and infections (e.g., herpes, nasopharyngitis, respiratory, and urinary). No serious infections or discontinuations associated with NNC0109-0012 were observed.

CONCLUSION

In this phase IIa trial, treatment with NNC0109-0012 (anti-IL-20 mAb) was effective in patients with seropositive RA as early as week 1, with further improvements to week 12. No safety or tolerability concerns were identified with weekly NNC0109-0012 administration.

Distribution of interleukin-10 family cytokines in serum and synovial fluid of patients with inflammatory arthritis reveals different contribution to systemic and joint inflammation

Evidence exists that interleukin (IL)-10 family cytokines may be involved in the pathogenesis of rheumatoid arthritis (RA). We sought to determine whether or not these cytokines are involved in psoriatic arthritis (PsA). We conducted a prospective study on patients with PsA, RA and osteoarthritis (OA); healthy controls (HC) were also included. We analysed IL-20, IL-24 and IL-19 serum and synovial fluid (SF) levels and change of serum levels following treatment with biological agents. IL-20 serum levels were increased in PsA and RA compared with OA patients and HC and with matched SF levels. IL-24 serum levels in PsA, RA and OA patients were higher than those in HC and also with respect to matched SF in PsA. IL-19 serum levels were higher in HC and OA compared with PsA and RA patients; IL-19 SF levels were higher in PsA and RA compared with OA patients, and in PsA compared with RA patients. PsA and RA patients showed a reduction of IL-19 serum levels after biological treatment. Therefore, IL-19 seems to be involved mainly in the joint inflammation, whereas IL-20 and IL-24 appear to participate mainly in the systemic responses. These findings may further the comprehension of the contribution of these cytokines to the inflammatory response involved in chronic arthritis, as well as to the development of novel therapeutic strategies.

Clinical pharmacokinetics of the anti-interleukin-20 monoclonal antibody NNC0109-0012 in healthy volunteers and patients with psoriasis or rheumatoid arthritis

INTRODUCTION

NNC0109-0012, a novel human monoclonal antibody that binds to and neutralizes the activity of interleukin-20, was investigated as a potential treatment for inflammatory diseases. Pharmacokinetic (PK) modeling was performed using data from four completed clinical phase 1/2 trials to better understand the clinical PK of NNC0109-0012.

METHODS

The populations included were patients with rheumatoid arthritis (RA), chronic plaque psoriasis, and healthy volunteers. NNC0109-0012 was administered subcutaneously at various dose levels (0.01-3 mg/kg) as single dose, once weekly, or multiple doses every second week for up to 12 doses. Noncompartmental methods were used to describe the PK parameters. Population PK was analyzed using nonlinear mixed-effects modeling, with body weight as the main covariate and gender, age, and population as additional covariates.

RESULTS

Across studies (N = 116), mean age and body weight ranged from 38 to 58 years and 72 to 96 kg, respectively. NNC0109-0012 displays linear PK. Time to maximum plasma concentration occurred at approximately 1 week, and the terminal half-life was approximately 3 weeks. Clearance and volume of distribution increased proportionally to body weight. No difference in clearance or volume of distribution was observed between gender or different age groups; however, clearance was slightly lower in healthy volunteers than in patients with RA.

CONCLUSION

The PK profile of NNC0109-0012 is similar to other monoclonal antibodies directed against soluble targets.

Inhibition of synovitis and joint destruction by a new single domain antibody specific for cyclophilin A in two different mouse models of rheumatoid arthritis

Introduction

Cyclophilin A (CypA) is implicated in rheumatoid arthritis (RA) pathogenesis. We studied whether a novel anti-CypA single domain antibody (sdAb) treatment would modulate the severity of the disease in two different animal models of RA.

Methods

A novel sdAb, named sdAbA1, was screened from an immunized camel sdAb library and found to have a high binding affinity (K_D = 6.9 × 10^-9 M) for CypA. The SCID-HuRAg model and the collagen-induced arthritis (CIA) in mice were used to evaluate the effects of sdAbA1 treatment on inflammation and joint destruction. For in vitro analysis, monocytes/macrophages were purified from synovial fluid and peripheral blood of patients with RA and were tested for the effect of anti-CypA sdAb on metalloproteinase (MMP) production. Human monocyte cell line THP-1 cells were selected and western blot analyses were performed to examine the potential signaling pathways.

Results

In the CIA model of RA, the sdAbA1 treatment resulted in a significant decrease in clinical symptoms as well as of joint damage (P <0.05). In the SCID-HuRAg model, treatment with anti-CypA antibody sdAbA1 significantly reduced cartilage erosion, inflammatory cell numbers and MMP-9 production in the implanted tissues (P <0.05). It also significantly reduced the levels of human inflammatory cytokines IL-6 and IL-8 in mouse serum (P <0.05). No toxic effects were observed in the two animal models. In vitro results showed that sdAbA1 could counteract CypA-dependent MMP-9 secretion and IL-8 production by interfering with the ERK-NF-κB pathway.

Conclusions

Blockade of CypA significantly inhibited synovitis and cartilage/bone erosion in the two tested animal models of RA. Our findings provide evidence that sdAbA1 may be a potential therapeutic agent for RA.

The discoidin domain receptor 2/annexin A2/matrix metalloproteinase 13 loop promotes joint destruction in arthritis through promoting migration and invasion of fibroblast-like synoviocytes

OBJECTIVE

Discoidin domain receptor 2 (DDR-2)/matrix metalloproteinase (MMP) signaling is an important pathway involved in cartilage destruction in rheumatoid arthritis (RA). However, the molecular mechanisms of this pathway have not been clearly identified. This study was undertaken to screen key molecules involved in this pathway and evaluate their biologic functions in synovium invasion of RA.

METHODS

DDR-2-interacting proteins were examined in vitro by immunoprecipitation and mass spectrometry, and annexin A2 was acquired. The effects of annexin A2 on fibroblast-like synoviocyte (FLS) migration were evaluated using a Transwell invasion assay and an Erasion trace test. In Ddr2(-/-) mice with collagen-induced arthritis (CIA), hematoxylin and eosin (H&E) staining, immunohistochemical analysis, and Western blot analysis were used to assess expression of DDR-2, annexin A2, and MMP-13, as well as synovial hyperplasia. Rats with CIA were treated with lentivirus annexin A2 small interfering RNA (siRNA), and annexin A2 siRNA effects on joint damage were analyzed based upon arthritis index scores and results of micro-computed tomography and H&E staining. The differences between annexin A2 expression in clinical samples from RA and osteoarthritis patients were compared using Western blotting.

RESULTS

Annexin 2 was identified for the first time as a DDR-2 binding protein. It may be phosphorylated by phospho-DDR-2, leading to MMP-13 secretion. The annexin A2 phosphorylation level and MMP-13 expression level were decreased and collagen-induced joint damage greatly reduced in Ddr2(-/-) mice. Joint damage in rats with CIA was significantly ameliorated when annexin A2 was down-regulated. Annexin A2 expression and phosphorylation were elevated in human RA synovial tissue.

CONCLUSION

Annexin A2 is a key molecule in the DDR-2/annexin A2/MMP-13 loop, the activation of which contributes to joint destruction in RA, mainly through promoting invasion of FLS. Annexin A2 might therefore become a novel clinical target for RA treatment.

IL-20 and IL-20R1 antibodies protect against liver fibrosis

Interleukin (IL)-20 is a proinflammatory cytokine of the IL-10 family and involved in rheumatoid arthritis, atherosclerosis, stroke, and osteoporosis. However, the pathophysiological roles of IL-20 in liver injury have not been extensively studied. We explored the involvement of IL-20 in liver injury and the therapeutic potential of IL-20 antagonists for treating liver fibrosis. Compared with normal liver tissue from healthy individuals, the amount of IL-20 was much higher in hepatocytes and hepatic stellate cells in liver biopsies from patients with fibrosis, cirrhosis, and hepatocellular carcinoma. Carbon tetrachloride (CCl4) treatment induced IL-20 that further up-regulated the expression of transforming growth factor (TGF)-β1 and p21(WAF1) and resulted in cell cycle arrest in the Clone-9 rat hepatocyte cell line. IL-20 activated quiescent rat hepatic stellate cells (HSCs) and up-regulated TGF-β1 expression. IL-20 also increased TGF-β1, tumor necrosis factor (TNF)-α, and type I collagen (Col-I) expression, and promoted the proliferation and migration of activated HSCs. Serum IL-20 was significantly elevated in mice with short-term and long-term CCl4 -induced liver injury. In mice with short-term liver injury, anti-IL-20 monoclonal antibody (7E) and anti-IL-20 receptor (IL-20R1) monoclonal antibody (51D) attenuated hepatocyte damage caused by CCl4, TGF-β1, and chemokine production. In mice with long-term liver injury, 7E and 51D inhibited CCl4 -induced cell damage, TGF-β1 production, liver fibrosis, HSC activation, and extracellular matrix accumulation, which was caused by the reduced expression of tissue inhibitors of metalloproteinases as well as increased metalloproteinase expression and Col-I production. IL-20R1-deficient mice were protected from short-term and long-term liver injury.

CONCLUSION

We identified a pivotal role of IL-20 in liver injury and showed that 7E and 51D may be therapeutic for liver fibrosis.

The Therapeutic Potential of Anti-Interleukin-20 Monoclonal Antibody

Interleukin (IL)-20, a member of the IL-10 family of cytokines, was discovered in 2001. IL-20 acts on multiple cell types by activating on a heterodimer receptor complex of either IL-20R1–IL-20R2 or IL-22R1–IL-20R2. Recent evidence indicates that IL-20's interaction with its receptors might have proinflammatory effects on chronic inflammatory diseases, particularly rheumatoid arthritis (RA), osteoporosis, and breast cancer. Updated information about IL-20, such as its identification, expression, receptors, signaling, and biological activities, is illustrated in this review based on our research and the data available in the literature. IL-20 is a pleiotropic cytokine, which promotes inflammation, angiogenesis, and chemotaxis. IL-20 also regulates osteoclast differentiation by altering the receptor activator of NF-κB (RANK) and RANK ligand (RANKL) axis. Inflammation, angiogenesis, and osteoclastogenesis are critical for the pathogenesis of RA, osteoporosis, and breast cancer-induced osteolysis. Based on the in vitro and in vivo data and clinical samples, we demonstrated that IL-20 plays pivotal roles in these three diseases. In experimental models, anti-IL-20 monoclonal antibody ameliorates arthritis severity, protects against ovariectomized-induced bone loss, and inhibits breast tumor-induced osteolysis. This review presents the clinical implications of IL-20, which will lead to a better understanding of the biological functions of IL-20 in these diseases and provide new therapeutic options in the future.

Therapeutic opportunities of the IL-22-IL-22R1 system

Interleukin-22 (IL-22) is a key effector molecule that is produced by activated T cells, including T helper 22 (TH22) cells, TH17 cells and TH1 cells, as well as subsets of innate lymphoid cells. Although IL-22 can act synergistically with IL-17 or tumour necrosis factor, some important functions of IL-22 are unique to this cytokine. Data obtained over the past few years indicate that the IL-22-IL-22 receptor subunit 1 (IL-22R1) system has a high potential clinical relevance in psoriasis, ulcerative colitis, graft-versus-host disease, certain infections and tumours, as well as in liver and pancreas damage. This Review highlights current knowledge of the biology of the IL-22-IL-22R1 system, its role in inflammation, tissue protection, regeneration and antimicrobial defence, as well as the positive and potentially negative consequences of its therapeutic modulation.

Decreased interleukin-20 level in patients with systemic sclerosis: are they related with angiogenesis?

In this study, we aimed to evaluate the relation between angiogenesis indicators and T helper 17 cytokine group in patients with systemic sclerosis (SSc) which is a disease characterized by impaired angiogenesis and autoimmune response. In our study, patients with SSc are compared with patients with primary Raynaud's phenomenon (RP) and healthy controls. Forty SSc patients, 18 primary RP cases, and 20 healthy controls were included in our study. The demographic and clinical features of patients with SSc were recorded. The serum levels of vascular endothelial growth factor (VEGF), vascular endothelial (VE)-cadherin, interleukin (IL)-20, IL-22, and IL-23 were assessed. In the SSc group, IL-20 level was significantly lower than in both primary RP group and controls (p values <0.001). VE-cadherin level in SSc was significantly higher than in primary RP (p = 0.016). The IL-22 and IL-23 and VEGF levels of SSc, primary RP, and control groups were similar (p values >0.05). In SSc patients, IL-23 correlated negatively with VEGF (r = -0.36, p = 0.025) and positively with VE-cadherin (r = 0.55, p < 0.001). IL-20 levels in SSc patients correlated with disease duration (r = 0.32, p = 0.044). SSc patients with limited involvement had significantly higher VE-cadherin levels than SSc patients with diffuse involvement (p = 0.044). We observed that IL-20 which is an IL-10 group angiogenesis indicator was observed to be suppressed in SSc, suggesting abnormal angiogenesis.

IL-10-- and IL-20--expressing epithelial and inflammatory cells are increased in patients with ulcerative colitis

Interleukin (IL)-20, a pro-inflammatory cytokine, is a recently discovered member of the IL-10 family. This cytokine has been described in inflammatory diseases such as psoriasis and asthma. However, IL-20 expression in ulcerative colitis (UC) patients has not been yet described. The aim of this study was to evaluate IL-20 and IL-10 gene and protein expression and their receptors in the mucosa from UC patients. Forty UC patients and 18 non-inflamed controls were studied. IL-10, IL-20, IL-10R1, IL-10R2, IL-20R1 and IL-20R2 gene expression was determined by real time RT-PCR in colonic biopsies. Protein expression was evaluated by immunohistochemistry. Patients in remission had significantly higher IL-10 gene expression in mucosa compared with active patients and controls. Conversely, IL-10R1/B gene expression was decreased in remission compared with active UC patients and controls. IL-20 gene expression was lower in colonic mucosa from UC patients in remission compared with controls and active patients. IL-20R1/B mRNA expression was higher in remission compared with active UC patients and controls. IHQ analysis showed an increased IL-10-, IL-20-, and IL-20R2-producing cells in active UC patients. IL-10-, IL-20- and IL-20R2-expressing epithelial and inflammatory cells were increased in active UC patients, meanwhile IL-20R1 was up-regulated only on inflammatory infiltrates vs. controls. This is the first depiction of the presence of IL-20 and its receptors in UC. Much remains to be learned however, about the pathogenic mechanisms that lead to IBD. This cytokine/receptor imbalance may be implicated in the pathogenesis of UC.

Anti-IL-20 monoclonal antibody alleviates inflammation in oral cancer and suppresses tumor growth

Interleukin-20 (IL-20) is a proinflammatory cytokine involved in rheumatoid arthritis, atherosclerosis, and osteoporosis. However, little is known about the role of IL-20 in oral cancer. We explored the function of IL-20 in the tumor progression of oral cancer. IL-20 expression levels in tumorous and nontumorous oral tissue specimens from 40 patients with four different stages oral cancer were analyzed with immunohistochemistry (IHC) staining and quantitative real-time PCR (qRT-PCR). Expression of IL-20 and its receptor subunits was higher in clinical oral tumor tissue than in nontumorous oral tissue. The role of IL-20 was examined in two oral cancer cell lines (OC-3 and OEC-M1). In vitro, IL-20 promoted TNF-α, IL-1β, MCP-1, CCR4, and CXCR4 and increased proliferation, migration, reactive oxygen species (ROS) production, and colony formation of oral cancer cells via activated STAT3 and AKT/JNK/ERK signals. To evaluate the therapeutic potential of anti-IL-20 monoclonal antibody 7E for treating oral cancer, an ex vivo tumor growth model was used. In vivo, 7E reduced tumor growth and inflammation in oral cancer cells. In conclusion, IL-20 promoted oral tumor growth, migration, and tumor-associated inflammation. Therefore, IL-20 may be a novel target for treating oral cancer, and anti-IL-20 monoclonal antibody 7E may be a feasible therapeutic.

Etanercept does not impair healing in rat models of tendon or metaphyseal bone injury

BACKGROUND AND PURPOSE

Should blockade of TNF-α be avoided after orthopedic surgery? Healing of injuries in soft tissues and bone starts with a brief inflammatory phase. Modulation of inflammatory signaling might therefore interfere with healing. For example, Cox inhibitors impair healing in animal models of tendon, ligament, and bone injury, as well as in fracture patients. TNF-α is expressed locally at increased levels during early healing of these tissues. We therefore investigated whether blocking of TNF-α with etanercept influences the healing process in established rat models of injury of tendons and metaphyseal bone.

METHODS

Rats were injected with etanercept, 3.5 mg/kg 3 times a week. Healing of transected Achilles tendons and bone healing around screws implanted in the tibial metaphysis were estimated by mechanical testing. Tendons were allowed to heal either with or without mechanical loading. Ectopic bone induction following intramuscular BMP-2 implants has previously been shown to be stimulated by etanercept in rodents. This was now tested as a positive control.

RESULTS

Tendon peak force after 10 days was not significantly influenced by etanercept. Changes exceeding 29% could be excluded with 95% confidence. Likewise, screw pull-out force was not significantly influenced. More than 25% decrease or 18% increase could be excluded with 95% confidence. However, etanercept treatment increased the amount of bone induced by intramuscular BMP-2 implants, as estimated by blind histological scoring.

INTERPRETATION

Etanercept does not appear to impair tendon or metaphyseal bone healing to any substantial degree.

Pathways for bone loss in inflammatory disease

Chronic inflammation including autoimmune disease is an important risk factor for the development of osteoporosis. Receptor activator of nuclear factor-κB ligand (RANKL) and macrophage colony-stimulating factor (M-CSF) play a central role in osteoclast differentiation and function, and the molecular pathways by which M-CSF and RANKL induce osteoclast differentiation have been analyzed in detail. Proinflammatory cytokines directly or indirectly regulate osteoclastogenesis and bone resorption providing a link between inflammation and osteoporosis. Tumor necrosis factor-α, interleukin (IL)-1, IL-6, and IL-17 are the most important proinflammatory cytokines triggering inflammatory bone loss. Inhibition of these cytokines has provided potent therapeutic effects in the treatment of diseases such as rheumatoid arthritis. Further investigation is needed to understand the pathophysiology and to develop new strategies to treat inflammatory bone loss. This review summarizes new data on inflammatory bone loss obtained in 2011.

Anti-IL-20 monoclonal antibody suppresses breast cancer progression and bone osteolysis in murine models

IL-20 is a proinflammatory cytokine involved in rheumatoid arthritis, atherosclerosis, and stroke. However, little is known about its role in breast cancer. We explored the function of IL-20 in tumor growth and metastasis, as well as in clinical outcome. Tumor expression of IL-20 was assessed by immunohistochemical staining among 198 patients with invasive ductal carcinoma of the breast, using available clinical and survival data. IL-20 expression was associated with advanced tumor stage, greater tumor metastasis, and worse survival. Reverse transcription quantitative polymerase chain reaction showed that clinical breast tumor tissue expressed higher levels of IL-20 and its receptors than did nontumorous breast tissue. IL-20 was also highly expressed in breast cancer bone-metastasis tissue. In vitro, IL-20 upregulated matrix metalloproteinase-9, matrix metalloproteinase-12, cathepsin K, and cathepsin G, and enhanced proliferation and migration of breast cancer cells, which were inhibited by anti-IL-20 mAb 7E. In vivo, we generated murine models to evaluate the therapeutic potential of 7E, using luminescence intensity, radiological scans, and micro-computed tomography. 7E reduced tumor growth, suppressed bone colonization, diminished tumor-mediated osteolysis, and lessened bone density decrement in mice injected with breast cancer cells. In conclusion, our results suggest that IL-20 plays pivotal roles in the tumor progression of breast cancer. IL-20 expression in breast cancer tissue is associated with a poor clinical outcome. Anti-IL-20 mAb 7E suppressed bone colonization and decreased osteolytic bone lesions. Therefore, IL-20 may be a novel target in treating breast tumor-induced osteolysis.

Purification, crystallization and preliminary X-ray diffraction analysis of the IL-20-IL-20R1-IL-20R2 complex

Interleukin-20 (IL-20) is an IL-10-family cytokine that regulates innate and adaptive immunity in skin and other tissues. In addition to protecting the host from various external pathogens, dysregulated IL-20 signaling has been shown to contribute to the pathogenesis of human psoriasis. IL-20 signals through two cell-surface receptor heterodimers, IL-20R1-IL-20R2 and IL-22R1-IL-20R2. In this report, crystals of the IL-20-IL-20R1-IL-20R2 ternary complex have been grown from polyethylene glycol solutions. The crystals belonged to space group P4(1)2(1)2 or P4(3)2(1)2, with unit-cell parameters a = 111, c = 135 Å, and diffracted X-rays to 3 Å resolution. The crystallographic asymmetric unit contains one IL-20-IL-20R1-IL-20R2 complex, corresponding to a solvent content of approximately 54%.