最近报道了在纤维化皮肤病变的成纤维细胞中过度表达均聚聚糖聚唾液酸(polySia)的异常唾液酸化。然而,polySia水平或唾液酸化的这种升高是否在功能上与成纤维细胞的促纤维化活化有关,以及它们向肌成纤维细胞的转变仍是未知的.因此,我们在此探讨了唾液酸化的抑制是否会干扰主纤维化介质转化生长因子β1(TGFβ1)诱导的皮肤成纤维细胞向肌成纤维细胞的转化过程.在用重组人TGFβ1刺激之前,用竞争性泛唾液酸转移酶抑制剂3-Fax-peracetic-Neu5Ac(3-Fax)预处理成人皮肤成纤维细胞,然后分析polysia的表达,细胞活力,扩散,迁移能力,并获得肌成纤维细胞样形态功能特征。用TGFβ1刺激皮肤成纤维细胞导致polysia的过表达,3-Fax预管理有效地削弱了这一点。3-Fax预处理可有效减少TGFβ1诱导的皮肤成纤维细胞增殖,迁移,细胞形态的变化,以及表型和功能分化为肌成纤维细胞,FAP的大幅下降证明了这一点,ACTA2,COL1A1,COL1A2和FN1基因表达,和α-平滑肌肌动蛋白,N-钙黏着蛋白,COL1A1和FN-EDA蛋白水平,以及收缩能力降低。此外,预先给予3-Fax的皮肤成纤维细胞显示Smad3依赖性经典TGFβ1信号传导显着降低。总的来说,我们的体外研究结果首次证明,随着polySia水平的增加,异常唾液酸化在皮肤成纤维细胞向肌成纤维细胞的转化中具有功能性作用,并提示竞争性唾液酸转移酶抑制可能为皮肤纤维化提供新的治疗机会.
Aberrant sialylation with overexpression of the homopolymeric glycan polysialic acid (polySia) was recently reported in fibroblasts from fibrotic skin lesions. Yet, whether such a rise in polySia levels or sialylation in general may be functionally implicated in profibrotic activation of fibroblasts and their transition to
myofibroblasts remains unknown. Therefore, we herein explored whether inhibition of sialylation could interfere with the process of skin fibroblast-to-myofibroblast transition induced by the master profibrotic mediator transforming growth factor β1 (TGFβ1). Adult human skin fibroblasts were pretreated with the competitive pan-sialyltransferase inhibitor 3-Fax-peracetyl-Neu5Ac (3-Fax) before stimulation with recombinant human TGFβ1, and then analyzed for polySia expression, cell viability, proliferation, migratory ability, and acquisition of myofibroblast-like morphofunctional features. Skin fibroblast stimulation with TGFβ1 resulted in overexpression of polySia, which was effectively blunted by 3-Fax pre-administration. Pretreatment with 3-Fax efficiently lessened TGFβ1-induced skin fibroblast proliferation, migration, changes in cell morphology, and phenotypic and functional differentiation into
myofibroblasts, as testified by a significant reduction in FAP, ACTA2, COL1A1, COL1A2, and FN1 gene expression, and α-smooth muscle actin, N-cadherin, COL1A1, and FN-EDA protein levels, as well as a reduced contractile capability. Moreover, skin fibroblasts pre-administered with 3-Fax displayed a significant decrease in Smad3-dependent canonical TGFβ1 signaling. Collectively, our in vitro findings demonstrate for the first time that aberrant sialylation with increased polySia levels has a functional role in skin fibroblast-to-myofibroblast transition and suggest that competitive sialyltransferase inhibition might offer new therapeutic opportunities against skin fibrosis.