OBJECTIVE To identify long noncoding RNAs (lncRNAs) associated with the inflammatory phenotype of synovial fibroblasts from obese patients with osteoarthritis (OA), and to explore the expression and function of these lncRNAs. METHODS Synovium was collected from normal-weight patients with hip fracture (non-OA; n = 6) and from normal-weight (n = 8) and obese (n = 8) patients with hip OA. Expression of RNA was determined by RNA-sequencing and quantitative reverse transcription-polymerase chain reaction. Knockdown of lncRNA was performed using LNA-based GapmeRs. Synovial fibroblast cytokine production was measured by enzyme-linked immunosorbent assay. RESULTS Synovial fibroblasts from obese patients with OA secreted greater levels of interleukin-6 (IL-6) (mean ± SEM 162 ± 21 pg/ml; P < 0.001) and CXCL8 (262 ± 67 pg/ml; P < 0.05) compared to fibroblasts from normal-weight patients with OA (IL-6, 51 ± 4 pg/ml; CXCL8, 78 ± 11 pg/ml) or non-OA patients (IL-6, 35 ± 3 pg/ml; CXCL8, 56 ± 6 pg/ml) (n = 6 patients per group). RNA-sequencing revealed that fibroblasts from obese OA patients exhibited an inflammatory transcriptome, with increased expression of proinflammatory messenger RNAs (mRNAs) as compared to that in fibroblasts from normal-weight OA or non-OA patients (>2-fold change, P < 0.05; n = 4 patients per group). A total of 19 lncRNAs were differentially expressed between normal-weight OA and non-OA patient fibroblasts, and a further 19 lncRNAs were differentially expressed in fibroblasts from obese OA patients compared to normal-weight OA patients (>2-fold change, P < 0.05 for each), which included the lncRNA for metastasis-associated lung adenocarcinoma transcript 1 (MALAT1). MALAT1 was rapidly induced upon stimulation of OA synovial fibroblasts with proinflammatory cytokines, and was up-regulated in the synovium from obese OA patients as compared to normal-weight OA patients (1.6-fold change, P < 0.001) or non-OA patients (6-fold change, P < 0.001). MALAT1 knockdown in OA synovial fibroblasts (n = 4 patients) decreased the levels of mRNA expression and protein secretion of CXCL8 (>1.5-fold change, P < 0.01), whereas it increased expression of mRNAs for TRIM6 (>2-fold change, P < 0.01), IL7R (<2-fold change, P < 0.01), HIST1H1C (>1.5-fold change, P < 0.001), and MAML3 (>1.5-fold change, P < 0.001). In addition, MALAT1 knockdown inhibited the proliferation of synovial fibroblasts from obese patients with OA. CONCLUSION Synovial fibroblasts from obese patients with hip OA exhibit an inflammatory phenotype. MALAT1 lncRNA may mediate joint inflammation in obese OA patients.

中文翻译：

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转移相关肺腺癌转录本 1 长非编码 RNA 在肥胖骨关节炎患者中对炎症性滑膜成纤维细胞表型的调节。

目的 鉴定与肥胖骨关节炎（OA）患者滑膜成纤维细胞炎症表型相关的长链非编码RNA（lncRNA），并探讨这些lncRNA的表达和功能。方法 从体重正常的髋部骨折患者（非 OA；n = 6）和体重正常（n = 8）和肥胖（n = 8）的髋关节 OA 患者中收集滑膜。通过 RNA 测序和定量逆转录聚合酶链反应确定 RNA 的表达。使用基于 LNA 的 GapmeR 进行 lncRNA 的敲低。通过酶联免疫吸附测定法测量滑膜成纤维细胞细胞因子的产生。结果 来自肥胖 OA 患者的滑膜成纤维细胞分泌更高水平的白细胞介素 6 (IL-6)（平均值 ± SEM 162 ± 21 pg/ml；P < 0.001）和 CXCL8（262 ± 67 pg/ml；P < 0。05) 与来自正常体重 OA 患者 (IL-6, 51 ± 4 pg/ml; CXCL8, 78 ± 11 pg/ml) 或非 OA 患者 (IL-6, 35 ± 3 pg/ml; CXCL8, 56 ± 6 pg/ml)（每组 n = 6 名患者）。RNA 测序显示，与来自正常体重 OA 或非 OA 患者的成纤维细胞相比，来自肥胖 OA 患者的成纤维细胞表现出炎症转录组，促炎信使 RNA (mRNA) 的表达增加（>2 倍变化，P < 0.05；n = 每组 4 名患者）。共有 19 个 lncRNA 在正常体重 OA 和非 OA 患者成纤维细胞之间差异表达，另外 19 个 lncRNA 在肥胖 OA 患者与正常体重 OA 患者的成纤维细胞中差异表达（>2 倍变化，P <每个 0.05），其中包括转移相关肺腺癌转录本 1 (MALAT1) 的 lncRNA。与正常体重的 OA 患者（变化 1.6 倍，P < 0.001）或非 OA 患者相比，MALAT1 在用促炎细胞因子刺激 OA 滑膜成纤维细胞后迅速诱导，并且在肥胖 OA 患者的滑膜中上调（1.6 倍变化，P < 0.001）。 6 倍变化，P < 0.001）。OA 滑膜成纤维细胞（n = 4 名患者）中的 MALAT1 敲低降低了 CXCL8 的 mRNA 表达和蛋白质分泌水平（> 1.5 倍变化，P < 0.01），而它增加了 TRIM6 mRNA 的表达（> 2 倍变化， P < 0.01）、IL7R（<2 倍变化，P < 0.01）、HIST1H1C（>1.5 倍变化，P < 0.001）和 MAML3（>1.5 倍变化，P < 0.001）。此外，MALAT1 敲低抑制了肥胖 OA 患者滑膜成纤维细胞的增殖。结论 来自肥胖髋关节 OA 患者的滑膜成纤维细胞表现出炎症表型。MALAT1 lncRNA 可能介导肥胖 OA 患者的关节炎症。