bioRxiv preprint doi: https://doi.org/10.1101/2020.08.22.258459; this version posted August 24, 2020. The copyright holder for this preprint (which was not certified by peer review) is the author/funder. All rights reserved. No reuse allowed without permission. 1 The inhaled steroid ciclesonide blocks SARS-CoV-2 RNA replication by targeting viral 2 replication-transcription complex in culture cells 3 4 Shutoku Matsuyamaa#, Miyuki Kawasea, Naganori Naoa, Kazuya Shiratoa, Makoto Ujikeb, Wataru 5 Kamitanic, Masayuki Shimojimad, and Shuetsu Fukushid 6 7 aDepartment of Virology III, National Institute of Infectious Diseases, Tokyo, Japan 8 bFaculty of Veterinary Medicine, Nippon Veterinary and Life Science University, Tokyo, Japan 9 cDepartment of Infectious Diseases and Host Defense, Gunma University Graduate School of 10 Medicine, Gunma, Japan 11 dDepartment of Virology I, National Institute of Infectious Diseases, Tokyo, Japan. 12 13 Running Head: Ciclesonide blocks SARS-CoV-2 replication 14 15 #Address correspondence to Shutoku Matsuyama,
[email protected] 16 17 Word count: Abstract 149, Text 3,016 bioRxiv preprint doi: https://doi.org/10.1101/2020.08.22.258459; this version posted August 24, 2020. The copyright holder for this preprint (which was not certified by peer review) is the author/funder. All rights reserved. No reuse allowed without permission. 18 Abstract 19 We screened steroid compounds to obtain a drug expected to block host inflammatory responses and 20 MERS-CoV replication. Ciclesonide, an inhaled corticosteroid, suppressed replication of MERS-CoV 21 and other coronaviruses, including SARS-CoV-2, the cause of COVID-19, in cultured cells. The 22 effective concentration (EC90) of ciclesonide for SARS-CoV-2 in differentiated human bronchial 23 tracheal epithelial cells was 0.55 μM.