Hemoxygenase-1 as a key mediator of acute radiation pneumonitis revealed in a human lung alveolus-on-a-chip

Abstract

ABSTRACTExposure to gamma radiation either due to environmental disasters or cancer radiotherapy can result in development of acute radiation syndrome (ARS), characterized by pneumonitis and lung fibrosis. We leveraged a microfluidic organ-on-a-chip lined by human lung alveolar epithelium interfaced with pulmonary endothelium to model acute radiation-induced lung injuryin vitro. Both lung epithelium and endothelium exhibited DNA damage, cellular hypertrophy, upregulation of inflammatory cytokines, and loss of barrier function within 6 h of radiation exposure, although greater damage was observed in the endothelium. Transcriptomic analysis revealed increased expression of the cytoprotective gene, hemoxygenase-1 (HMOX-1) and gene network analysis identified it as a central mediator of radiation-induced injury. Pharmacological stimulation of HMOX-1 activity also significantly reduced acute radiation-induced lung injury, although it enhanced damage at later times. Thus, this human lung chip offers a new platform to study ARS and these results suggest that HMOX-1 may be mechanistically involved in this injury response.