Wang Xu, Zhu Yuting, Sun Congcong, Wang Tao, Shen Yingjie, Cai Wanhui, Sun Jia, Chi Lisha, Wang Haijun, Song Na, Niu Chao, Shen Jiayi, Cong Weitao, Zhu Zhongxin, Xuan Yuanhu, Li Xiaokun, Jin Litai
Key Laboratory of Biotechnology Pharmaceutical Engineering, School of Pharmaceutical Sciences, Wenzhou Medical University Wenzhou, China.
Haining Hospital of Traditional Chinese Medicine Haining, China.
Front Pharmacol. 2017 Feb 3;8:32. doi: 10.3389/fphar.2017.00032. eCollection 2017.
Skin wound healing is a complex process requiring the coordinated behavior of many cell types, especially in the proliferation and migration of fibroblasts. Basic fibroblast growth factor (bFGF) is a member of the FGF family that promotes fibroblast migration, but the underlying molecular mechanism remains elusive. The present RNA sequencing study showed that the expression levels of several canonical Wnt pathway genes, including , , , , and () were modified by bFGF stimulation in fibroblasts. Enzyme-linked immunosorbent assay (ELISA) analysis also showed that Wnt pathway was activated under bFGF treatment. Furthermore, treatment of fibroblasts with lithium chloride or IWR-1, an inducer and inhibitor of the Wnt signaling pathway, respectively, promoted and inhibited cell migration. Also, levels of cytosolic glycogen synthase kinase 3 beta phosphorylated at serine (pGSK3β Ser) and nuclear β-catenin were increased upon exposure to bFGF. Molecular and biochemical assays indicated that phosphoinositide 3-kinase (PI3K) signaling activated the GSK3β/β-catenin/Wnt signaling pathway via activation of c-Jun N-terminal kinase (JNK), suggesting that PI3K and JNK act at the upstream of β-catenin. In contrast, knock-down of β delayed fibroblast cell migration even under bFGF stimulation. RNA sequencing analysis of β knock-down fibroblasts demonstrated that β-catenin positively regulated the transcription of and Moreover, FGF21 treatment activated AKT and JNK, and accelerated fibroblast migration to a similar extent as bFGF does. In addition, ELISA analysis demonstrated that both of bFGF and FGF21 were auto secretion factor and be regulated by Wnt pathway stimulators. Taken together, our analyses define a feedback regulatory loop between bFGF (FGF21) and Wnt signaling acting through β-catenin in skin fibroblasts.
皮肤伤口愈合是一个复杂的过程，需要多种细胞类型的协同作用，尤其是在成纤维细胞的增殖和迁移方面。碱性成纤维细胞生长因子（bFGF）是促进成纤维细胞迁移的FGF家族成员，但其潜在的分子机制仍不清楚。目前的RNA测序研究表明，在成纤维细胞中，bFGF刺激可改变几个经典Wnt通路基因的表达水平，包括 、 、 、 和 （ ）。酶联免疫吸附测定（ELISA）分析也表明，在bFGF处理下Wnt通路被激活。此外，分别用Wnt信号通路的诱导剂氯化锂或抑制剂IWR-1处理成纤维细胞，可促进和抑制细胞迁移。而且，暴露于bFGF后，丝氨酸磷酸化的细胞溶质糖原合酶激酶3β（pGSK3β Ser）和细胞核β-连环蛋白水平升高。分子和生化分析表明，磷酸肌醇3-激酶（PI3K）信号通过激活c-Jun氨基末端激酶（JNK）激活GSK3β/β-连环蛋白/Wnt信号通路，提示PI3K和JNK在β-连环蛋白的上游起作用。相反，即使在bFGF刺激下，敲低β也会延迟成纤维细胞迁移。对敲低β的成纤维细胞进行RNA测序分析表明，β-连环蛋白正向调节 和 的转录。此外，FGF21处理可激活AKT和JNK，并在与bFGF相似的程度上加速成纤维细胞迁移。另外，ELISA分析表明，bFGF和FGF21都是自分泌因子，并受Wnt通路刺激剂调节。综上所述，我们的分析确定了bFGF（FGF21）和通过β-连环蛋白作用于皮肤成纤维细胞的Wnt信号之间的反馈调节环。
