Chemokine (C-C Motif) Ligand 20, a Potential Biomarker for Graves' Disease, Is Regulated by Osteopontin

Xiaoli Li,Xiaoli Li,Xiaoli Li,Xiaoli Li,Fengjiao Huang,Jie Hong,Jie Hong,Lingyan Xu,Lingyan Xu,Lingyan Xu,Lingyan Xu,Lingyan Xu,Xiaohua Jiang,Xiaohua Jiang,Yicheng Qi,Xinran Ma,Xinran Ma,Xinran Ma,Xinran Ma,Xinran Ma,Guang Ning,Guang Ning,Guang Ning,Guang Ning,Hua Guo,Hua Guo,Bin Cui,Bin Cui,Bin Cui,Bin Cui,Shu Wang,Shu Wang,Shu Wang,Shu Wang,Dongping Lin,Paul Proost

doi:10.1371/journal.pone.0064277

Abstract

ContextGraves’ disease (GD) is a common autoimmune disease involving the thyroid gland. The altered balance of pro- and anti-inflammatory cytokines plays an important role in the pathogenesis of GD. Chemokine (C-C motif) ligand 20 (CCL20) is important for interleukin-17 (IL-17) signal activation and a potent chemoattractant for Th17 cells. Meanwhile, Osteopontin (OPN), a broadly expressed pleiotropic cytokine, has been implicated in GD through inducing Th1-involved response to enhance the production of proinflammatory cytokines and chemokines, but little is known about the role of OPN in regulating CCL20 and IL-17 signaling.ObjectiveThis study sought to explore the possibility of CCL20 level as a biomarker for GD, as well as investigate the role of OPN in regulating CCL20 production.MethodsFifty untreated GD patients, fifteen euthyroid GD patients, twelve TRAb-negative GD patients and thirty-five healthy control donors were recruited. OPN, CCL20 and other clinical GD diagnosis parameters were measured. CD4+T cells were isolated from peripheral blood mononuclear cells (PBMCs) using antibody-coated magnetic beads. Enzyme-linked immune-sorbent assay and quantitative polymerase chain reaction were used to determine CCL20 expression level.ResultsWe found that the plasma CCL20 level was enhanced in GD patients and decreased in euthyroid and TRAb-negative GD patients. In addition, CCL20 level correlated with GD clinical diagnostic parameters and plasma OPN level. Moreover, we demonstrated that recombinant OPN and plasma from untreated GD patients increased the expression of CCL20 in CD4+T cells, which could be blocked by OPN antibody. Furthermore, we found that the effect of OPN on CCL20 expression was mediated by β3 integrin receptor, IL-17, NF-κB and MAPK pathways.ConclusionsThese results demonstrated that CCL20 might serve as a biomarker for GD and suggested the possible role of OPN in induction of CCL20 expression.

Highlights

Graves’ disease (GD) is a common organ-specific autoimmune disease characterized by the reactivity to self-thyroid antigens
We found that the plasma CCL20 level was enhanced in GD patients and decreased in euthyroid and thyrotropin receptor antibody (TRAb)-negative GD patients
We demonstrated that recombinant OPN and plasma from untreated GD patients increased the expression of CCL20 in CD4+T cells, which could be blocked by OPN antibody

Summary

Introduction

Graves’ disease (GD) is a common organ-specific autoimmune disease characterized by the reactivity to self-thyroid antigens. The pathogenesis of the disease remains elusive, evidences indicated that destruction of the balance of Th1/Th2 cells and Treg/Th17 cells could alter the expressions of pro- and anti-inflammatory cytokines resulting in thyroid lymphocytic infiltration and B cell activation, with antibody production against thyroid antigens, which in turn played a pivotal role in the pathogenesis of GD [1,2]. The previous study demonstrated that the proportion of the Th17 cells increased in intractable GD patients, who remained positive for anti-thyrotropin receptor antibody (TRAb) despite being treated with anti-thyroid drugs [8]. IL-17 produced from Th17 cells is a strong inducer of CCL20 expression in many cell types [12,13]. The positive regulatory loop indicates that CCL20 level is closely related to IL17 signal activation. CCL20 has been implicated in several autoimmune diseases, such as rheumatoid arthritis (RA) and Experimental Autoimmune Encephalomyelitis (EAE) [11,12,14], little is known about the association of CCL20 with GD and its regulatory factors

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Results

Conclusion