Gene Expression Analysis of Murine and Human Osteoarthritis Synovium Reveals Elevation of Transforming Growth Factor β-Responsive Genes in Osteoarthritis-Related Fibrosis
Gene Expression Analysis of Murine and Human Osteoarthritis Synovium Reveals Elevation of Transforming Growth Factor β-Responsive Genes in Osteoarthritis-Related Fibrosis
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DOI：
10.1002/art.38266
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发表时间：
2014-03-01
影响因子：
13.3
通讯作者：
van der Kraan, P. M.
中科院分区：
文献类型：
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作者：
Remst, D. F. G.;Blom, A. B.;van der Kraan, P. M.
Objective.滑膜纤维化是骨关节炎（OA）关节僵硬的主要原因。转化生长因子β（TGF β）在OA中升高，在滑膜纤维化的发生和持续中起关键作用。然而，在OA中阻断TGF β作为纤维化的治疗干预不是一种选择，因为TGF β对于软骨维持和修复至关重要。因此，我们进行了本研究，以寻求TGF β下游的目标，以防止OA相关的纤维化，而不干扰关节内环境稳定。进行实验以确定参与细胞外基质转换的基因是否对TGF β有反应并且在OA相关纤维化中升高。我们分析了TGF β刺激的人OA滑膜成纤维细胞和TGF β诱导的纤维化小鼠、实验性OA小鼠和终末期OA人类滑膜中的基因表达。通过微阵列、低密度阵列或定量聚合酶链反应分析确定基因表达。我们观察到在所有OA相关纤维化条件下，前胶原基因和编码胶原交联酶的基因的表达增加。比较TGF β刺激的人OA滑膜成纤维细胞、实验性OA小鼠滑膜和终末期OA人滑膜中的基因表达，发现基因PLOD 2、LOX、COL1A1、COL5A1和TIMP 1在所有这些条件下均上调。此外，我们证实了这些基因在TGF β诱导的滑膜纤维化小鼠体内被TGF β上调。本研究中鉴定的大多数上调基因由于其在关节中的关键功能，将是治疗开发的不良靶点。然而，高度上调的基因PLOD 2，负责形成胶原交联，使胶原不太容易被酶降解，是一个有吸引力的和有前途的目标，在OA相关的滑膜纤维化的干扰。
Objective. Synovial fibrosis is a major contributor to joint stiffness in osteoarthritis (OA). Transforming growth factor beta (TGF beta), which is elevated in OA, plays a key role in the onset and persistence of synovial fibrosis. However, blocking of TGF beta in OA as a therapeutic intervention for fibrosis is not an option since TGF beta is crucial for cartilage maintenance and repair. Therefore, we undertook the present study to seek targets downstream of TGF beta for preventing OA-related fibrosis without interfering with joint homeostasis.Methods. Experiments were performed to determine whether genes involved in extracellular matrix turnover were responsive to TGF beta and were elevated in OA-related fibrosis. We analyzed gene expression in TGF beta-stimulated human OA synovial fibroblasts and in the synovium of mice with TGF beta-induced fibrosis, mice with experimental OA, and humans with end-stage OA. Gene expression was determined by microarray, low-density array, or quantitative polymerase chain reaction analysis.Results. We observed an increase in expression of procollagen genes and genes encoding collagen crosslinking enzymes under all of the OA-related fibrotic conditions investigated. Comparison of gene expression in TGF beta-stimulated human OA synovial fibroblasts, synovium from mice with experimental OA, and synovium from humans with end-stage OA revealed that the genes PLOD2, LOX, COL1A1, COL5A1, and TIMP1 were up-regulated in all of these conditions. Additionally, we confirmed that these genes were up-regulated by TGF beta in vivo in mice with TGF beta-induced synovial fibrosis.Conclusion. Most of the up-regulated genes identified in this study would be poor targets for therapy development, due to their crucial functions in the joint. However, the highly up-regulated gene PLOD2, responsible for the formation of collagen crosslinks that make collagen less susceptible to enzymatic degradation, is an attractive and promising target for interference in OA-related synovial fibrosis.