Department of Anatomy, Physiology and Cell Biology, School of Veterinary Medicine, University of California, Davis, California 95616, USA.
Toxicol Sci. 2010 Feb;113(2):453-67. doi: 10.1093/toxsci/kfp268. Epub 2009 Oct 30.
While the role of trefoil factors (TFF) in the maintenance of epithelial integrity in the gastrointestinal tract is well known, their involvement in wound healing in the conducting airway is less well understood. We defined the pattern of expression of TFF1, TFF2, and TFF3 in the airways of mice during repair of both severe (300 mg/kg) and moderate (200 mg/kg) naphthalene-induced Clara cell injury. Quantitative real-time PCR for tff messenger RNA expression and immunohistochemistry for protein expression were applied to airway samples obtained by microdissection of airway trees or to fixed lung tissue from mice at 6 and 24 h and 4 and 7 days after exposure to either naphthalene or an oil (vehicle) control. All three TFF were expressed in normal whole lung and airways. TFF2 was the most abundant and was enriched in airways. Injury of the airway epithelium by 300 mg/kg naphthalene caused a significant induction of tff1 gene expression at 24 h, 4 days, and 7 days. In contrast, tff2 was decreased in the high-dose group at 24 h and 4 days but returned to baseline levels by 7 days. tff3 gene expression was not significantly changed at any time point. Protein localization via immunohistochemistry did not directly correlate with the gene expression measurements. TFF1 and TFF2 expression was most intense in the degenerating Clara cells in the injury target zone at 6 and 24 h. Following the acute injury phase, TFF1 and TFF2 were localized to the luminal apices of repairing epithelial cells and to the adjacent mesenchyme in focal regions that correlated with bifurcations and the bronchoalveolar duct junction. The temporal pattern of increases in TFF1, TFF2, and TFF3 indicate a role in cell death as well as proliferation, migration, and differentiation phases of airway epithelial repair.
虽然三叶因子 (TFF) 在维持胃肠道上皮完整性方面的作用众所周知，但它们在传导气道的伤口愈合中的作用知之甚少。我们定义了 TFF1、TFF2 和 TFF3 在小鼠严重（300mg/kg）和中度（200mg/kg）萘诱导的 Clara 细胞损伤修复过程中在气道中的表达模式。应用定量实时 PCR 检测 tff 信使 RNA 表达，免疫组织化学检测蛋白表达，对气道树微解剖获得的气道样本或暴露于萘或油（对照）后 6、24 小时和 4、7 天的小鼠固定肺组织进行检测。所有三种 TFF 在正常全肺和气道中均有表达。TFF2 最为丰富，在气道中富集。300mg/kg 萘对气道上皮的损伤导致 tff1 基因表达在 24 小时、4 天和 7 天显著诱导。相比之下，tff2 在高剂量组在 24 小时和 4 天减少，但在 7 天恢复到基线水平。tff3 基因表达在任何时间点均无明显变化。通过免疫组织化学进行的蛋白定位与基因表达测量没有直接相关。TFF1 和 TFF2 表达在损伤靶区的变性 Clara 细胞中在 6 和 24 小时最强。在急性损伤阶段之后，TFF1 和 TFF2 定位于修复上皮细胞的腔顶和局灶性区域的相邻间质，这些区域与分叉和支气管肺泡导管交界处相关。TFF1、TFF2 和 TFF3 的增加时间模式表明它们在细胞死亡以及气道上皮修复的增殖、迁移和分化阶段发挥作用。
