Protective Effects of Endothelin-2 Expressed in Epithelial Cells on Bleomycin-Induced Pulmonary Fibrosis in Mice.

Abstract

Initially, endothelin (ET)-2 was described as an endothelium-derived vasoconstrictor. However, accumulating evidence suggests the involvement of ET-2 in non-cardiovascular physiology and disease pathophysiology. The deficiency of ET-2 in mice can be lethal, and such mice exhibit a distinct developmental abnormality in the lungs. Nonetheless, the definite role of ET-2 in the lungs remains unclear. The ET-2 isoform, ET-1, promotes pulmonary fibrosis in mice. Although endothelin receptor antagonists (ERAs) show improvements in bleomycin-induced pulmonary fibrosis in mouse models, clinical trials examining ERAs for pulmonary fibrosis treatment have been unsuccessful, even showing harmful effects in patients. We hypothesized that ET-2, which activates the same receptor as ET-1, plays a distinct role in pulmonary fibrosis. In this study, we showed that ET-2 is expressed in the lung epithelium, and ET-2 deletion in epithelial cells of mice results in the exacerbation of bleomycin-induced pulmonary fibrosis. ET-2 knockdown in lung epithelial cell lines resulted in increased apoptosis mediated via oxidative stress induction. In contrast to the effects of ET-1, which induced fibroblast activation, ET-2 hampered fibroblast activation in primary mouse lung fibroblast cells by inhibiting the TGF-β-SMAD2/3 pathway. Our results demonstrated the divergent roles of ET-1 and ET-2 in pulmonary fibrosis pathophysiology and suggested that ET-2, expressed in epithelial cells, exerts protective effects against the development of pulmonary fibrosis in mice.

• Authors: Aristi Intan Soraya, Yoko Suzuki, Mitsuru Morimoto, Chemyong Jay Ko, Koji Ikeda, Ken-Ichi Hirata, Noriaki Emoto
• Journal: The Kobe journal of medical sciences (Kobe J Med Sci) Vol. 67 Issue 2 Pg. E61-E70 (Nov 02 2021) ISSN: 1883-0498 [Electronic] Japan
• PMID: 34795157 (Publication Type: Journal Article)

Chemical References

• Endothelin-2
• Transforming Growth Factor beta
• Bleomycin

Topics

• Animals
• Bleomycin (administration & dosage, toxicity)
• Endothelin-2 (metabolism)
• Epithelial Cells
• Epithelium (metabolism, pathology)
• Lung (metabolism, pathology)
• Mice
• Pulmonary Fibrosis (chemically induced, metabolism)
• Transforming Growth Factor beta (metabolism)