ABSTRACT Acute respiratory distress syndrome (ARDS) causes respiratory failure, affects more than 200,000 people annually, and has a mortality rate approaching forty percent. There are no molecularly targeted treatments for ARDS and clinicians utilize life-support with mechanical ventilation (MV) to give patients time to recover. Although lifesaving, MV can cause injury known as ventilator-induced lung injury (VILI). One mechanism by which MV induces VILI is through pulmonary surfactant dysfunction. We have identified a protein, annexin A2 (AnxA2), that is phosphorylated during VILI and is known to play a role in surfactant release. We hypothesize that injurious forces during VILI lead to phosphorylation of AnxA2 and impaired surfactant function by inhibiting actin bundling at the site of lamellar body fusion in alveolar type 2 (AT2) epithelial cells. Aim 1 will define the mechanism by which AnxA2 phosphorylation impairs surfactant function using a murine pre-clinical ARDS model. Aim 2 will determine how AnxA2 phosphorylation regulates surfactant release from AT2 cells using a novel, human ventilator-on-a-chip device. The scientific goal of this proposal is to identify novel molecular targets to treat or prevent surfactant dysfunction during ARDS and ameliorate the harmful effects of MV in critically ill patients. The research approach has been structured to support a training plan that will provide training for the principal investigator (Dr. Bentley) in several skills, including (1) becoming proficient in the fabrication and use of microscale models of the alveolar micro-environment and primary human lung cell isolation and culture, (2) the generation and use of cell-specific genetically modified mice, and (3) gaining expertise in murine models of lung injury. Additionally, Dr. Bentley will participate in didactic courses, workshops, and national conferences to build skills in grant writing and networking. The proposed work will also support the preparation and submission of 1-2 first-author manuscripts to build a publication portfolio. The training plan and mentorship committee assembled in this proposal will assist the principle investigator (Dr. Bentley) in attaining the skills and mentorship necessary to submit a competitive NIH career development (K-series) award at the end of the award period. Taken together, this proposal will assist the PI in attaining his goal of becoming an independent physician-scientist with expertise in acute lung injury.

Project Narrative Acute respiratory distress syndrome (ARDS) causes respiratory failure, and patients frequently require life- support with mechanical ventilation when affected with ARDS. Mechanical ventilation can be lifesaving but can also cause an injury known as ventilator induced lung injury (VILI), which is at least partly due to surfactant dysfunction. This proposal will deepen our understanding of the mechanisms that drive surfactant dysfunction in VILI and identify novel therapeutic targets to improve the outcomes of patients with ARDS who require mechanical ventilation.