A potential role of the JNK pathway in hyperoxia-induced cell death, myofibroblast transdifferentiation and TGF-β1-mediated injury in the developing murine lung
1 Division of Perinatal Medicine, Department of Pediatrics, Yale University School of Medicine, New Haven, CT 06520, USA
2 Division of Neonatology, Department of Pediatrics, Harbor UCLA Medical Center, David Geffen School of Medicine at UCLA, Torrance, CA, 90502, USA
3 Department of Anesthesiology, Qilu Hospital of Shandong University, No. 107 Wenhua West Road, Lixia District, 250012 Jinan, Shandong, China
4 Department of Systems Biology, Beth Israel Deaconess Medical Center, Center for Life Sciences, 3 Blackfan Circle, Boston, MA 02115, USA
BMC Cell Biology 2011, 12:54 doi:10.1186/1471-2121-12-54Published: 15 December 2011
Transforming growth factor-beta 1 (TGF-β1) has been implicated in hyperoxia-induced cell death and impaired alveolarization in the developing lung. In addition, the c-JunNH2-terminal kinase (JNK) pathway has been shown to have a role for TGF-β1-mediated effects. We hypothesized that the JNK pathway is an important regulator of hyperoxia-induced pulmonary responses in the developing murine lung.
We used cultured human lung epithelial cells, fetal rat lung fibroblasts and a neonatal TGF-β1 transgenic mouse model. We demonstrate that hyperoxia inhibits cell proliferation, activates cell death mediators and causes cell death, and promotes myofibroblast transdifferentiation, in a dose-dependent manner. Except for fibroblast proliferation, the effects were mediated via the JNK pathway. In addition, since we observed increased expression of TGF-β1 by epithelial cells on exposure to hyperoxia, we used a TGF-β1 transgenic mouse model to determine the role of JNK activation in TGF-β1 induced effects on lung development and on exposure to hyperoxia. We noted that, in this model, inhibition of JNK signaling significantly improved the spontaneously impaired alveolarization in room air and decreased mortality on exposure to hyperoxia.
When viewed in combination, these studies demonstrate that hyperoxia-induced cell death, myofibroblast transdifferentiation, TGF-β1- and hyperoxia-mediated pulmonary responses are mediated, at least in part, via signaling through the JNK pathway.