Department of Clinical Immunology, State Key Discipline of Cell Biology, Xijing Hospital, Fourth Military Medical University, Xi'an, Shaanxi Province, China.
J Rheumatol. 2012 Mar;39(3):574-82. doi: 10.3899/jrheum.101257. Epub 2012 Jan 15.
HLA-B27 positivity strongly influences the susceptibility to and phenotype of spondyloarthropathies (SpA). This study was designed to screen factors that activate the promoter of HLA-B27 in U937 cells, and to assess whether these promoter-activating factors induce the unfolded protein response (UPR) in HLA-B27-expressing cells.
Cytometric Bead Array, flow cytometry, and real-time polymerase chain reaction were used to detect the expression of cytokines and UPR-associated proteins in peripheral blood and synovial fluid of patients with SpA. The HLA-B27 promotor transfectant was incubated separately with cytokines and Toll-like receptor ligands. After interferon-γ (IFN-γ) stimulation, expressions of GRP78, CHOP, and XBP-1 were tested in HLA-B27-expressing U937 cells and peripheral blood mononuclear cell (PBMC) of patients with ankylosing spondylitis (AS). (Clinical trial registration no. ChiCTR-OCC-11001565)
Expressions of GRP78, CHOP, and XBP-1 in monocytes/macrophages of SpA peripheral blood and synovial fluid were higher than those in healthy controls and patients with osteoarthritis (OA) (p < 0.05). Tumor necrosis factor-α (TNF-α) and IFN-α, IFN-ß, and IFN-γ were found to have activated the HLA-B27 promoter in the U937 cell line (p < 0.05). Following stimulation with IFN-γ, the expressions of GRP78, CHOP and XBP-1 in HLA-B27-transfected U937 cells and PBMC of HLA-B27-positive AS patients were more intense than those in A2-U937 cells, HLA-B27-negative AS patients, or healthy controls (p < 0.05).
Expressions of GRP78, CHOP, and XBP-1 were higher in monocytes/macrophages of patients with SpA than those in both OA patients and healthy controls, suggesting that UPR may participate in the pathogenesis of SpA. TNF-α and IFN-α, IFN-ß, and IFN-γ significantly activated HLA-B27 promoter in the U937 cell line, and IFN-γ, the strongest activating factor, may induce the UPR in HLA-B27-expressing cells.
HLA-B27 阳性强烈影响脊柱关节病（SpA）的易感性和表型。本研究旨在筛选激活 U937 细胞中 HLA-B27 启动子的因素，并评估这些启动子激活因子是否在 HLA-B27 表达细胞中诱导未折叠蛋白反应（UPR）。
使用流式细胞术和实时聚合酶链反应检测 SpA 患者外周血和滑液中细胞因子和 UPR 相关蛋白的表达。将 HLA-B27 启动子转染体分别与细胞因子和 Toll 样受体配体孵育。用干扰素-γ（IFN-γ）刺激后，检测 HLA-B27 表达的 U937 细胞和强直性脊柱炎（AS）患者外周血单个核细胞（PBMC）中 GRP78、CHOP 和 XBP-1 的表达。（临床试验注册号 ChiCTR-OCC-11001565）
SpA 外周血和滑液中单核细胞/巨噬细胞中 GRP78、CHOP 和 XBP-1 的表达高于健康对照组和骨关节炎（OA）患者（p < 0.05）。肿瘤坏死因子-α（TNF-α）和 IFN-α、IFN-β 和 IFN-γ被发现激活了 U937 细胞系中的 HLA-B27 启动子（p < 0.05）。用 IFN-γ刺激后，HLA-B27 转染的 U937 细胞和 HLA-B27 阳性 AS 患者 PBMC 中 GRP78、CHOP 和 XBP-1 的表达均高于 A2-U937 细胞、HLA-B27 阴性 AS 患者和健康对照组（p < 0.05）。
SpA 患者单核细胞/巨噬细胞中 GRP78、CHOP 和 XBP-1 的表达高于 OA 患者和健康对照组，提示 UPR 可能参与 SpA 的发病机制。TNF-α和 IFN-α、IFN-β 和 IFN-γ显著激活了 U937 细胞系中的 HLA-B27 启动子，而最强的激活因子 IFN-γ可能在 HLA-B27 表达细胞中诱导 UPR。
