Compound 1

The 727-member NIH Clinical Collection (NIH-CC) was obtained from Scripps Molecular Screening Center. The NIH-CC is a small molecule library comprised of drugs that have been in Phase I or II clinical trials. Thus, compounds were selected for drug-likeness, bioavailability, and stability. The 95-member Kinase library (SYNLibrary-95, catalog # SYN-2103) was purchased from Synkinase. SYNLibrary-95 contains a kinase inhibitor library that recognizes 57 targets. Three pre-mRNA splicing regulators were obtained from the California Institute for Biomedical Research (Calibr). The 201-member RNA-focused compound library was obtained from Scripps Molecular Screening Center. These compounds were previously identified by performing chemical similarity search based on molecules that possess bis-benzimidazole or similar cores (Rzuczek, et al., 2015 (link)). Hit compounds were re-purchased in larger quantities for testing. Compound 1 was purchased from Cayman Chemicals, while 2 and 3 were purchased from Biotang, Inc.

Immortalized hSAECs were previously described.^{37 (link),38 (link)} hSAECs were grown in SAGM small airway epithelial cell growth medium (Lonza, Walkersville, MD) in a humidified atmosphere of 5% CO₂. Poly(I:C) was obtained from Sigma (St. Louis, MO) and used at 10 μg/mL in the cell culture. Compound 1 was purchased from Tocris and compound 3 was either purchased from Cayman Chemical (Ann Arbor, Michigan) or resynthesized in house. Compounds were dissolved in DMSO and added at the indicated concentrations.