Th22 Cells Promote Osteoclast Differentiation via Production of IL-22 in Rheumatoid Arthritis

Abstract

T helper (Th) cells can differentiate into functionally distinct subsets and play a pivotal role in inflammatory and autoimmune diseases such as rheumatoid arthritis (RA). Th22 cells have been identified as a new subset secreting interleukin (IL)-22. Although elevated levels of IL-22 in the synovial fluids of RA patients were reported, its pathological roles remain unclear. Here, we demonstrated that IL-22 was characteristically produced from CD3+CD4+CC-chemokine receptor (CCR)4+CCR6+CCR10+ cells and their ability of the production of IL-22 markedly exceeded that of other Th subsets and the subset, thereby, designated Th22 cells. Th22 cells were efficiently induced by the stimulation with tumor necrosis factor-α, IL-6, and IL-1β. Th22 cells were markedly infiltrated in synovial tissue in patients with active RA, but not in patients with osteoarthritis (OA). CCL17, CCL20, and CCL28, which are chemokine ligands of CCR4, CCR6, and CCR10, respectively, were abundantly expressed in RA synovial tissue compared to OA. By in vitro Trans-well migration assay, Th22 cells efficiently migrated toward CCL28. Co-culture of Th22 cells, which were sorted from peripheral blood, with monocytes in the presence of macrophage colony-stimulating factor and receptor activator of nuclear factor (NF)-κB ligand induced osteoclasts formation more efficiently than that of either Th1 cells or Th17 cells. Furthermore, IL-22 markedly augmented osteoclast differentiation by promoting nuclear factor of activated T cells c1 expression in CD14+ monocytes. Contrarily, the addition of IFN-γ to the culture significantly decreased osteoclasts number, whereas IL-17 had marginal effects. IL-22 neutralizing antibody inhibited osteoclast formation in the co-culture of Th22 cells with CD14+ monocytes. Collectively, the results indicated that Th22 cells, which co-express chemokine receptors CCR4, CCR6, and CCR10, possess strong potency of tissue migration and accumulate into inflamed synovial tissues where the ligands such as CCL28 are highly expressed. Thus, Th22 cells have the capacity to promote osteoclast differentiation through production of IL-22 and thus play a pivotal role in bone destruction in patients with RA.

Interleukin-22 deficiency alleviates doxorubicin-induced oxidative stress and cardiac injury via the p38 MAPK/macrophage/Fizz3 axis in mice

“…IL-22 is an important inflammatory regulator secreted mainly by immune cells, including macrophages and lymphocytes; however, it is also secreted in small quantities by non-immune cells, such as cardiomyocytes and fibroblasts [ [9] , [10] , [11] ]. The target cells for IL-22 are epithelial cells, and increasing numbers of recent studies have shown that the IL-22 receptor can be expressed on the surfaces of immune cells and that IL-22 can regulate the differentiation of immune cells [ [12] , [13] , [14] , [15] , [16] ]. In addition, numerous studies have shown that IL-22 can participate in a variety of cardiovascular diseases, including hypertension, cardiac hypertrophy, atherosclerosis, and myocardial infarction [ [17] , [18] , [19] , [20] ].…”

Th17 Cells and the IL-23/IL-17 Axis in the Pathogenesis of Periodontitis and Immune-Mediated Inflammatory Diseases

“…Furthermore, upregulated TNF and IL-17 can synergistically lead to further stimulation of the fibroblasts and epithelial cells to secrete IL-6, IL-8, PGE2, and the neutrophil chemoattractants; thus, intensifying the inflammation [35]. Independently from IL-17, IL-22 was also demonstrated to increase synovial inflammation in rheumatoid arthritis joints and clinical attachment loss in periodontitis patients, similarly to its proinflammatory function in psoriasis [118,119,120].…”

Interleukin (IL)-25 suppresses IL-22-induced osteoclastogenesis in rheumatoid arthritis via STAT3 and p38 MAPK/IκBα pathway

“…Elevated IL-22 levels in plasma can predict future bone erosion in RA [ 22 ], and IL-22 produced by natural killer (NK) cells can induce FLS proliferation [ 9 ]. Furthermore, IL-22 has been reported to promote osteoclastogenesis via the p38 MAPK/NF-κB and JAK2/STAT-3 signaling pathways [ 8 ]; Th22 cells have been shown to play a crucial role in osteoclastogenesis by producing IL-22 [ 23 ]. These findings collectively support the pathological roles of IL-22 in RA pathogenesis and progression.…”