Kyung Hee University, Gangdong-gu, Seoul, Korea.
Rheumatology (Oxford). 2012 Mar;51(3):443-50. doi: 10.1093/rheumatology/ker327. Epub 2011 Nov 28.
To further understand the expression regulation of MMP-1 and MMP-13 under physiological and pathological conditions, we investigated the combined effects of hypoxia and pro-inflammatory stimuli on the expression of MMP-1 and MMP-13 in rheumatoid synovial fibroblasts.
Synovial fibroblasts were cultured under either hypoxic or normoxic conditions in the presence of IL-1β stimulation. The culture supernatant was analysed for secreted levels of VEGF, MMP-1 and MMP-13. Their gene expression was quantified with real-time and semi-quantitative PCR. Another group of cells was transfected with small-interfering RNA (siRNA) specific for hypoxia-inducible factor-1 α (HIF-1α). The protein levels of HIF-1α were detected by western blot analysis.
In response to 10 ng/ml of IL-1β under normoxia, the levels of MMP-1 and MMP-13 increased compared with the levels observed under hypoxia. IL-1β stimulation under hypoxia induced a 2-fold increase in the level of MMP-1 and a 2-fold decrease in the level of MMP-13 compared with cells cultured under normoxia. A similar pattern of differential expression for MMP-1 and MMP-13 was observed with 1 and 5 ng/ml IL-1β, but not at 0.1 ng/ml. The differential expression of MMPs under the combined effect of IL-1β and hypoxia was significantly attenuated by silencing HIF-1α with siRNA.
Hypoxia in arthritic joints may differentially affect the IL-1β-stimulated expression of MMP-1 and MMP-13 in rheumatoid synovial fibroblasts. This effect is dependent on HIF-1α expression. This hypoxia-mediated differential effect should be taken into consideration when testing the efficiency of therapies that target HIF-1α.
为了进一步了解 MMP-1 和 MMP-13 在生理和病理条件下的表达调控，我们研究了缺氧和促炎刺激物对类风湿滑膜成纤维细胞中 MMP-1 和 MMP-13 表达的联合作用。
在 IL-1β 刺激下，滑膜成纤维细胞在缺氧或常氧条件下培养。分析细胞培养上清液中 VEGF、MMP-1 和 MMP-13 的分泌水平。采用实时和半定量 PCR 定量检测其基因表达。另一组细胞用针对缺氧诱导因子-1α（HIF-1α）的小干扰 RNA（siRNA）转染。用 Western blot 分析检测 HIF-1α的蛋白水平。
在常氧条件下，10ng/ml 的 IL-1β 刺激下，MMP-1 和 MMP-13 的水平与缺氧条件下相比有所增加。与常氧培养的细胞相比，缺氧条件下 IL-1β 刺激诱导 MMP-1 水平增加 2 倍，MMP-13 水平降低 2 倍。用 1 和 5ng/ml 的 IL-1β 观察到 MMP-1 和 MMP-13 的表达差异具有相似的模式，但用 0.1ng/ml 的 IL-1β 时则没有。用 siRNA 沉默 HIF-1α 后，MMPs 在 IL-1β 和缺氧联合作用下的差异表达显著减弱。
关节炎关节中的缺氧可能会对类风湿滑膜成纤维细胞中 IL-1β 刺激的 MMP-1 和 MMP-13 的表达产生差异影响。这种影响依赖于 HIF-1α 的表达。在测试针对 HIF-1α 的治疗方法的疗效时，应考虑这种缺氧介导的差异效应。
