Department of Pathology and Pathophysiology, Zhejiang University School of Medicine, P.O. Box 59, 866 Yuhangtang Rd., Hangzhou 310058, China.
FASEB J. 2012 Jun;26(6):2338-50. doi: 10.1096/fj.11-200139. Epub 2012 Feb 23.
Type II alveolar epithelial (AT-II) cells produce pulmonary surfactant proteins that are essential for alveolar function. AT-II is a major target in lung injury, and ineffective repair of damaged alveolar epithelia has been postulated to cause pulmonary fibrosis. Previous studies have shown that tyrosine phosphatase Shp2 is expressed highly in the embryonic lung epithelial buds, and Shp2 activity is required for FGF-induced lung branching morphogenesis. To investigate in vivo function of pulmonary Shp2, we generated alveoli epithelia-specific Shp2-knockout (Shp2(Δ/Δ)) mice. Shp2(Δ/Δ) mice exhibit marked reduction in surfactant proteins, disorganized lamellar bodies, increased alveolar epithelial apoptosis, and interstitial pulmonary fibrosis without preceding inflammation. Mechanistically, Shp2 acts to mediate expression of thyroid transcription factor 1 (TTF1) and ATP-binding cassette subfamily A member 3 (ABCA3). Shp2 also plays a central role in mediating FGF/GAB/ERK activity, required for epithelial repair program. Together, our results identify a novel role of tyrosine phosphatase Shp2 in surfactant homeostasis, and deregulation of Shp2 triggers spontaneous pulmonary fibrosis with minimal inflammation.
II 型肺泡上皮 (AT-II) 细胞产生肺表面活性蛋白,这对于肺泡功能至关重要。AT-II 是肺损伤的主要靶点,受损的肺泡上皮细胞的修复无效被认为是导致肺纤维化的原因。先前的研究表明,酪氨酸磷酸酶 Shp2 在胚胎肺上皮芽中表达水平较高,并且 FGF 诱导的肺分支形态发生需要 Shp2 活性。为了研究肺 Shp2 的体内功能,我们生成了肺泡上皮细胞特异性 Shp2 敲除(Shp2(Δ/Δ))小鼠。Shp2(Δ/Δ) 小鼠表现出明显的表面活性蛋白减少、板层小体排列紊乱、肺泡上皮细胞凋亡增加和间质性肺纤维化,而没有先前的炎症。在机制上,Shp2 介导甲状腺转录因子 1 (TTF1) 和 ABC 转运蛋白 A 成员 3 (ABCA3) 的表达。Shp2 还在介导 FGF/GAB/ERK 活性方面发挥核心作用,这是上皮修复程序所必需的。总之,我们的结果确定了酪氨酸磷酸酶 Shp2 在表面活性物质稳态中的新作用,Shp2 的失调会引发自发性肺纤维化,而炎症最小。