Zhang Mary Yinghua, Fang Shuyi, Gao Hongyu, Zhang Xiaoli, Gu Dongsheng, Liu Yunlong, Wan Jun, Xie Jingwu
Department of Pediatrics, The Wells Center for Pediatric Research, Indiana University School of Medicine, Indianapolis, IN, USA.
Department of BioHealth Informatics, School of Informatics and Computing At IUPUI, Indiana University, Indianapolis, IN, USA.
Cell Biosci. 2021 Feb 23;11(1):40. doi: 10.1186/s13578-021-00553-0.
We report our discovery of an important player in the development of skin fibrosis, a hallmark of scleroderma. Scleroderma is a fibrotic disease, affecting 70,000 to 150,000 Americans. Fibrosis is a pathological wound healing process that produces an excessive extracellular matrix to interfere with normal organ function. Fibrosis contributes to nearly half of human mortality. Scleroderma has heterogeneous phenotypes, unpredictable outcomes, no validated biomarkers, and no effective treatment. Thus, strategies to slow down scleroderma progression represent an urgent medical need. While a pathological wound healing process like fibrosis leaves scars and weakens organ function, oral mucosa wound healing is a scarless process. After re-analyses of gene expression datasets from oral mucosa wound healing and skin fibrosis, we discovered that several pathways constitutively activated in skin fibrosis are transiently induced during oral mucosa wound healing process, particularly the amphiregulin (Areg) gene. Areg expression is upregulated ~ 10 folds 24hrs after oral mucosa wound but reduced to the basal level 3 days later. During bleomycin-induced skin fibrosis, a commonly used mouse model for skin fibrosis, Areg is up-regulated throughout the fibrogenesis and is associated with elevated cell proliferation in the dermis. To demonstrate the role of Areg for skin fibrosis, we used mice with Areg knockout, and found that Areg deficiency essentially prevents bleomycin-induced skin fibrosis. We further determined that bleomycin-induced cell proliferation in the dermis was not observed in the Areg null mice. Furthermore, we found that inhibiting MEK, a downstream signaling effector of Areg, by selumetinib also effectively blocked bleomycin-based skin fibrosis model. Based on these results, we concluded that the Areg-EGFR-MEK signaling axis is critical for skin fibrosis development. Blocking this signaling axis may be effective in treating scleroderma.
我们报告了我们在皮肤纤维化(硬皮病的一个标志)发展过程中发现的一个重要因素。硬皮病是一种纤维化疾病,影响7万至15万美国人。纤维化是一种病理性伤口愈合过程,会产生过多的细胞外基质,干扰正常器官功能。纤维化导致近一半的人类死亡。硬皮病具有异质性表型、不可预测的结果、没有经过验证的生物标志物,也没有有效的治疗方法。因此,减缓硬皮病进展的策略代表了迫切的医疗需求。虽然像纤维化这样的病理性伤口愈合过程会留下疤痕并削弱器官功能,但口腔黏膜伤口愈合是一个无疤痕的过程。在对口腔黏膜伤口愈合和皮肤纤维化的基因表达数据集进行重新分析后发现,在皮肤纤维化中持续激活的几条信号通路在口腔黏膜伤口愈合过程中被短暂诱导,尤其是双调蛋白(Areg)基因。口腔黏膜伤口后24小时,Areg表达上调约10倍,但3天后降至基础水平。在博来霉素诱导的皮肤纤维化(一种常用的皮肤纤维化小鼠模型)中,Areg在整个纤维化过程中上调,并与真皮中细胞增殖增加有关。为了证明Areg在皮肤纤维化中的作用,我们使用了Areg基因敲除小鼠,发现Areg缺乏基本上可以预防博来霉素诱导的皮肤纤维化。我们进一步确定,在Areg基因缺失的小鼠中未观察到博来霉素诱导的真皮细胞增殖。此外,我们发现,用司美替尼抑制Areg下游信号效应器MEK也能有效阻断基于博来霉素的皮肤纤维化模型。基于这些结果,我们得出结论,Areg-表皮生长因子受体(EGFR)-MEK信号轴对皮肤纤维化发展至关重要。阻断该信号轴可能对治疗硬皮病有效。