Temperature synchronisation of circadian rhythms in primary human airway epithelial cells from children.

Introduction: Cellular circadian rhythms regulate immune pathways and inflammatory responses that mediate human disease such as asthma. Circadian rhythms in the lung may also contribute to exacerbations of chronic diseases such as asthma by regulating observed rhythms in mucus production, bronchial reactivity, airway inflammation and airway resistance. Primary human airway epithelial cells (AECs) are commonly used to model human lung diseases, such as asthma, with circadian symptoms, but a method for synchronising circadian rhythms in AECs has not been developed, and the presence of circadian rhythms in human AECs remains uninvestigated.

Methods: We used temperature cycling to synchronise circadian rhythms in undifferentiated and differentiated primary human AECs. Reverse transcriptase-quantitative PCR was used to measure expression of the core circadian clock genes and .

Results: Following temperature synchronisation, the core circadian genes and maintained endogenous 24-hour rhythms under constant conditions. Following serum shock, the core circadian genes and demonstrated rhythmic expression. Following temperature synchronisation, demonstrated rhythmic circadian expression.

Conclusions: Temperature synchronised circadian rhythms in AECs differentiated at an air-liquid interface can serve as a model to investigate circadian rhythms in pulmonary diseases.