Hyaluronan Orchestrates Transforming Growth Factor-β1-dependent Maintenance of Myofibroblast Phenotype
Hyaluronan Orchestrates Transforming Growth Factor-β1-dependent Maintenance of Myofibroblast Phenotype
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DOI：
10.1074/jbc.m806989200
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发表时间：
2009-04-03
影响因子：
4.8
通讯作者：
Phillips, Aled
中科院分区：
文献类型：
--
作者：
Webber, Jason;Meran, Soma;Phillips, Aled
成纤维细胞向肌成纤维细胞的分化是伤口愈合的关键。然而，在器官纤维化的背景下，这些肌成纤维细胞的持久性与进展性疾病有关。本研究探讨了肌成纤维细胞表型维持的控制机制。在成纤维细胞中加入转化生长因子-β1(TGF-β1)(10 ng/ml)诱导成纤维细胞，在去除转化生长因子-β1后，其表型可维持120h。Western印迹显示pSmad2和pSmad3的持续磷酸化，尽管外源性的转化生长因子-β1被去除。这种持续性是由于转化生长因子-β1的自分泌合成，这种合成被抗转化生长因子-β1抗体和碱性蛋白5抑制剂SB431542抑制。表型的持久性还与透明质酸(HA)生成增加、透明粘附素TSG6的合成以及HA细胞周毛的形成有关。这些都被转化生长因子-β受体阻断剂所抑制。为了进一步研究HA合成的重要性，4-甲基伞形酮被用来耗尽细胞质中对HA链延长至关重要的UDP-葡萄糖醛酸池。这阻止了细胞周围HA基质的形成，并减少了α-SMA的表达。而4-甲基伞形酮对Smad2和-3的磷酸化无影响。同样，用短干扰RNA抑制HAS2可以阻止表型激活，而不改变依赖于转化生长因子-β1的Smad的磷酸化，从而表明HA依赖的细胞表型调节独立于Smad的激活。这些数据表明，纤维化区的肌成纤维细胞通过自分泌转化生长因子-β1的作用维持其自身的表型，细胞外透明质酸基质是其重要的介导物。我们提出了一个模型，在该模型中，细胞周围HA基质的形成调节Smad依赖的自分泌转化生长因子-β1激活的信号转导的结果，从而调节肌成纤维细胞表型的持久性。
The differentiation of resident fibroblasts to myofibroblasts is central to wound healing. In the context of organ fibrosis, however, persistence of these myofibroblasts is associated with progressive disease. This study examines mechanisms controlling the maintenance of the myofibroblast phenotype. Myofibroblasts were induced by adding transforming growth factor-beta 1 (TGF-beta 1) (10 ng/ml) to fibroblasts for 72 h. The phenotype was maintained for up to 120 h following removal of TGF-beta 1. Western blot for pSmad2 and -3 demonstrated persistent phosphorylation despite removal of exogenous TGF-beta 1. This persistence was because of autocrine synthesis of TGF-beta 1, which was inhibited by both anti-TGF-beta 1 antibody and the ALK5 inhibitor SB431542. Persistence of phenotype was also associated with increased hyaluronan (HA) generation, synthesis of the hyaladherin TSG6, and HA pericellular coat formation. These were all inhibited by TGF-beta receptor blockade. To further investigate the importance of HA synthesis, 4-methylumbelliferone was used to deplete the cytoplasmic pool of UDP-glucuronic acid, essential for HA chain elongation. This prevented formation of the pericellular HA matrix and decreased expression of alpha-SMA. 4-Methylumbelliferone had no effect, however, on Smad2 and -3 phosphorylation. Similarly inhibition of HAS2 by short interfering RNA prevented phenotypic activation without altering TGF-beta 1-dependent Smad phosphorylation, thus suggesting that HA-dependent regulation of cell phenotype was independent of Smad activation. These data suggest that myofibroblasts in areas of fibrosis maintain their own phenotype through autocrine TGF-beta 1 action and that extracellular HA matrices are an essential mediator of this. We propose a model in which the formation of the pericellular HA matrix regulates the outcome of Smad-dependent autocrine TGF-beta 1-activated signaling, and therefore persistence of the myofibroblast phenotype.