1. The IL-33:ST2 axis is unlikely to play a central fibrogenic role in idiopathic pulmonary fibrosis
- Author
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Katherine E. Stephenson, Joanne Porte, Aoife Kelly, William A. Wallace, Catherine E. Huntington, Catherine L. Overed-Sayer, E. Suzanne Cohen, R. Gisli Jenkins, and Alison E. John
- Subjects
Idiopathic pulmonary fibrosis ,IL-33 ,ST2 ,Fibroblasts ,Bleomycin-induced pulmonary fibrosis ,Precision-cut lung slices ,Diseases of the respiratory system ,RC705-779 - Abstract
Abstract Background Idiopathic pulmonary fibrosis (IPF) is a devastating interstitial lung disease (ILD) with limited treatment options. Interleukin-33 (IL-33) is proposed to play a role in the development of IPF however the exclusive use of prophylactic dosing regimens means that the therapeutic benefit of targeting this cytokine in IPF is unclear. Methods IL-33 expression was assessed in ILD lung sections and human lung fibroblasts (HLFs) by immunohistochemistry and gene/protein expression and responses of HLFs to IL-33 stimulation measured by qPCR. In vivo, the fibrotic potential of IL-33:ST2 signalling was assessed using a murine model of bleomycin (BLM)-induced pulmonary fibrosis and therapeutic dosing with an ST2-Fc fusion protein. Lung and bronchoalveolar lavage fluid were collected for measurement of inflammatory and fibrotic endpoints. Human precision-cut lung slices (PCLS) were stimulated with transforming growth factor-β (TGFβ) or IL-33 and fibrotic readouts assessed. Results IL-33 was expressed by fibrotic fibroblasts in situ and was increased by TGFβ treatment in vitro. IL-33 treatment of HLFs did not induce IL6, CXCL8, ACTA2 and COL1A1 mRNA expression with these cells found to lack the IL-33 receptor ST2. Similarly, IL-33 stimulation had no effect on ACTA2, COL1A1, FN1 and fibronectin expression by PCLS. Despite having effects on inflammation suggestive of target engagement, therapeutic dosing with the ST2-Fc fusion protein failed to reduce BLM-induced fibrosis measured by hydroxyproline content or Ashcroft score. Conclusions Together these findings suggest the IL-33:ST2 axis does not play a central fibrogenic role in the lungs with therapeutic blockade of this pathway unlikely to surpass the current standard of care for IPF.
- Published
- 2023
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