Conditionally reprogrammed asthmatic bronchial epithelial cells express lower FOXJ1 at terminal differentiation and lower IFNs following RV-A1 infection

Primary bronchial epithelial cells (pBECs) obtained from donors have limited proliferation capacity. Recently, conditional reprogramming (CR) technique has overcome this and has provided the potential for extended passaging and subsequent differentiation of cells at air-liquid interface (ALI). However, there has been no donor-specific comparison of cell morphology, baseline gene expression, barrier function and anti-viral responses compared to their 'parent' pBECs, especially cells obtained from asthma donors. We, therefore, collected and differentiated pBECs at ALI from mild asthma donors (n=6) for the parent group. The same cells were conditionally reprogrammed and later differentiated at ALI. Barrier function was measured during the differentiation phase. Morphology and baseline gene expression were compared at terminal differentiation. Viral replication kinetics and anti-viral responses were assessed following RV infection over 96 hours. Barrier function during the differentiation phase and cell structural morphology at terminal differentiation appear similar in both parent and CR groups, however, there were elongated cell structures superficial to basal cells and significantly lower FOXJ1 expression in CR group. Anti-viral responses were also lower in CR group compared to parent asthma group following RV infection. The CR technique is a beneficial tool to proliferate pBECs over extended passages. Considering lower FOXJ1 expression, viral replication kinetics and anti-viral responses, a cautious approach should be taken while choosing CR cells for experiments. In addition, as lab-to-lab cell culture techniques vary, the most appropriate technique must be utilized to best match individual cell functions and morphologies to address specific research questions and experimental reproducibility across the labs.