The Effect of Different Concentrations TGF-β1 on Phenotype and Function of Type II Alveolar Epithelial Cell Line MLE-12

Liu Fangjun, Song Sisi, Deng Chun, Guo Chunbao, Fu Zhou, Liu Enmei, Liu Sha, Tan li, Gong Caihui^*

Children’s Hospital of Chongqing Medical University, Department of Respiratory Medicine, Key Laboratory of Pediatrics in Chongqing, Chongqing International Science and Technology Cooperation Center for Child Development and Disorders, Ministry of Educatio

Abstract: To investigate the phenotype and function of type II alveolar epithelial cells induced by TGF-β1 with different concentrations and times， the type II alveolar epithelial cell line MLE-12 cells were randomly divided into following groups， control group (0 ng/mL)， low concentration group (0.1 ng/mL)， middle concentration group (1 ng/mL)， and high concentration group (10 ng/mL). The morphological changes of each group， the protein and mRNA expressions of AEC II -specific marker (lung surfactant protein B， SP-B) and fibroblast-specific marker (fibroblast-specific protein 1， FSP-1) were observed at 12， 24， 48， 72 h by Double-labeled immunofluorescence and Real-time PCR， respectively. The results demonstrated that with the time and concentration of exposure to TGF-β1， the shape of AECII cells were gradually changed the pebble-like sharp into spindle， and gained some fibroblast appearance. With their morphological changes， the protein expression of SP-B in AECII cells were decreased， while the expression of FSP1 were increased， co-expressed were observed in 48 hours of middle concentration group and 24 hours of high concentration group. In parallel with the changes， the mRNA expression of SP-B were decreaseed markedly， but compared with control group for the same time the mRNA expression of FSP1 increased significantily. Nevertheless， different results with low concentration group had not been observed. TGF-β1 can induce type II alveolar epithelial cells transition to fibroblast (EMT) in a time and concentration dependent manner.

CSTR: 32200.14.cjcb.2014.04.0017