Int J Biol Sci 2023; 19(10):3042-3056. doi:10.7150/ijbs.80140 This issue Cite
Research Paper
1. The State Key Laboratory of Medicinal Chemical Biology, College of Pharmacy and Key Laboratory of Molecular Drug Research, Nankai University.
2. High-throughput Molecular Drug Screening Centre, Tianjin International Joint Academy of Biomedicine, Tianjin, China.
3. Department of Respiratory Medicine, Characteristic Medical Center of the Chinese People's Armed Police Force, Tianjin, China.
4. Department of Respiratory and Critical Care Medicine, Tianjin Beichen Hospital, No. 7 Beiyi Road, Beichen District, Tianjin 300400, China.
5. Department of Respiratory & Critical Care Medicine,Tianjin Chest Hospital,No.261,Taierzhuang South Road, Jinnan District,Tianjin 300222,China.
6. Department of Respiratory and Critical Care Medicine, Beijing Hospital, National Center of Gerontology, Beijing 100730, People's Republic of China.
7. Department of Respiratory Medicine, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China.
*These authors contributed equally: Hai-long Li, Jinhe Li and Yayue Hu
Forkhead box protein O3 (FOXO3) has good inhibition ability toward fibroblast activation and extracellular matrix, especially for the treatment of idiopathic pulmonary fibrosis. How FOXO3 regulates pulmonary fibrosis remains unclear. In this study, we reported that FOXO3 had binding sequences with F-spondin 1 (SPON1) promoter, which can activate its transcription and selectively promote the expression of SPON1 circRNA (circSPON1) but not mRNA expression. We further demonstrated that circSPON1 was involved in the extracellular matrix deposition of HFL1. In the cytoplasm, circSPON1 directly interacted with TGF-β1-induced Smad3 and inhibited the activation of fibroblasts by inhibiting nuclear translocation. Moreover, circSPON1 bound to miR-942-5p and miR-520f-3p that interfered with Smad7 mRNA and promoted Smad7 expression. This study revealed the mechanism of FOXO3-regulated circSPON1 in the development of pulmonary fibrosis. Potential therapeutic targets and new insights into the diagnosis and treatment of idiopathic pulmonary fibrosis based on circRNA were also provided.
Keywords: Idiopathic pulmonary fibrosis, FOXO3, circSPON1, Smad3, Smad7