PT - JOURNAL ARTICLE AU - Yoko Miura AU - Hirotsugu Ohkubo AU - Akio Niimi AU - Satoshi Kanazawa TI - Suppression of epithelial abnormalities by nintedanib in induced-rheumatoid arthritis-associated interstitial lung disease mouse model AID - 10.1183/23120541.00345-2021 DP - 2021 Oct 01 TA - ERJ Open Research PG - 00345-2021 VI - 7 IP - 4 4099 - http://openres.ersjournals.com/content/7/4/00345-2021.short 4100 - http://openres.ersjournals.com/content/7/4/00345-2021.full SO - erjor2021 Oct 01; 7 AB - Rheumatoid arthritis-associated interstitial lung disease (RA-ILD) is relevant for the prognosis in patients with RA. Nintedanib, which inhibits both receptor and non-receptor type tyrosine kinases, is an antifibrotic drug for the treatment of progressive fibrosing ILDs, such as idiopathic pulmonary fibrosis and systemic sclerosis-associated interstitial lung disease. Little is known about the effects of nintedanib on RA-ILD. We examined the characteristics of a novel induced RA-ILD (iRA-ILD) mouse model and the effects of nintedanib on the model.D1CC×D1BC mice are highly susceptible to arthritogenic antigens, such as bovine type II collagen, resulting in severe inflammatory arthritis. ILD develops after joint inflammation is alleviated. Serum surfactant protein D levels were monitored as an ILD marker. Nintedanib was orally administered to iRA-ILD mice for 2 months.The iRA-ILD model showed similar symptoms to those in patients with RA-ILD. The histopathological features of pulmonary disorder resembled nonspecific interstitial pneumonia, but with metaplastic epithelium. Histopathological analysis revealed that in addition to reducing fibrosis, nintedanib suppressed M2 macrophage polarisation and hyperplasia of Type 2 alveolar epithelial cells. The metaplastic epithelium acquired invasiveness because of the expression of E-cadherin, MMP7, Tgf-β, Col1a1, Padi2 and Padi4. Moreover, citrullinated peptides were detected in these invasive epithelial cells as well as in the bronchiolar epithelium. Administration of nintedanib reduced the expression of Pad4 and citrullinated peptides and eliminated invasive epithelial cells.The broad inhibitory effects of nintedanib on tyrosine kinases may contribute to the overall improvement in RA-ILD, including epithelial abnormalities associated with progressive lung fibrosis.A novel induced RA-ILD mouse model develops progressive lung fibrosis similar to NSIP, with epithelial abnormalities. Nintedanib provides a therapeutic intervention in the model, suggesting evidence of improvement in patients with RA-ILD. https://bit.ly/3yivzt1