Post-Translational Modification of Annexin A2 Mediates Surfactant Dysfunction During Injurious Mechanical Ventilation

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.

Grant Number: 5F32HL176082-02
NIH Institute/Center: NIH
Principal Investigator: Ian Bentley