Abstract Introduction Molecular circadian rhythms regulate cellular processes underlying health including innate immune pathways. Prior studies have indicated that viral infections abolish circadian rhythms in the airways of mice, but investigation in human cell models of airway epithelium has been limited. Using primary human airway epithelial cells differentiated at an air-liquid interface as an ex vivo organotypic model from healthy donors and donors with asthma, we investigated circadian rhythms in airway epithelial cells and the response to interferon stimulation. Methods Primary airway epithelial cells (AECs) from healthy donors (n=7) and donors with pediatric asthma (n=2) were differentiated at an air-liquid interface to an organotypic epithelium in temperature cycled incubators. Intrinsic circadian rhythmicity following temperature cycling was confirmed using BMAL1:Luciferase recordings and western blotting for BMAL1. At circadian time 0 hours and circadian time 12 hours, interferon-beta (10ng/mL) or polyI:C as a viral mimic was added to the media. BMAL1:Luciferase recordings were obtained from 5 days of continuous recording. Results Temperature cycles of 12 hours at 37C and 12 hours at 34C for 6 days reliably synchronized intrinsic circadian rhythms measured in luciferase assays in AECs. Circadian amplitude and period was similar between healthy AECs and AECs from donors with asthma by gene expression and BMAL:Luciferase recording. Treatment with interferon-beta or polyI:C did not alter circadian period or phase, but reduced BMAL:Luciferase amplitude by 50%. Conclusion The core circadian clock genes maintain rhythmicity in healthy and asthma airway epithelia. Interferon stimulation or polyI:C stimulation as a viral infection mimic reduces amplitude of circadian rhythmicity. Future work will investigate reduced circadian rhythmicity with altered innate immune signaling. Support (if any) SRS (WTP), Parker B Francis Fellowship (WTP), NIH K08HL179396 (WTP), NIH R01AI163160 (JSD), NIH K24AI150991 (JSD), NIH U19AI175089 (JSD).
Jahn et al. (Fri,) studied this question.