Acute Respiratory Distress Syndrome (ARDS) is a severe medical condition which is characterized by significant alveolar fluid accumulation and insufficient gas exchange. Cardiac surgery, ECMO, and use of cardiac medications are all known risk factors for ARDS which also complicates management of these and other cardiovascular diseases. Effective alveolar fluid clearance and repair of a functional alveolar-capillary barrier are considered the primary mechanisms for edema resolution in ARDS. Apart from enhancing fluid clearance, the Na+,K+-ATPase has been shown important for alveolar barrier function. Our lab showed that overexpression of the Na+,K+-ATPase b1 subunit into lungs enhances alveolar barrier integrity in previously injured lungs in mice and pigs. Previous in vitro data indicated that MRCKa mediates the upregulation of tight junction (TJ) proteins and epithelial barrier integrity by b1 overexpression. I hypothesize that the b1-Na+,K+-ATPase regulates alveolar barrier function through MRCKa in vivo. I will determine 1) whether MRCKa is required for the upregulation of TJ proteins and barrier function by b1 gene delivery in vivo, and 2) whether overexpression of MRCKa alone is sufficient to protect and/or treat lipopolysaccharides (LPS) induced lung injury in mice. LPS will be delivered by oropharyngeal aspiration to induce lung injury. Various plasmids will be delivered to mouse lungs by electroporation. For aim 1, plasmid to knockdown MRCKa or an MRCKa inhibitor will be delivered to lungs 24 hours before gene transfer of plasmid to overexpress b1. If required for signaling, MRCKa knockdown or inhibition will abolish b1's induction of TJ proteins and barrier upregulation. For aim 2, mice will be challenged with LPS 24 hours after (protection study) or before (treatment study) gene transfer. At end points, various assays will be performed to assess lung injury. It is expected that overexpression of MRCKa alone will be sufficient to protect and treat LPS induced acute lung injury, decreasing lung injury and increasing TJ expression; overexpression of both MRCKa and b1 subunit will augment the protection and treatment of LPS injured lungs to give the greatest reduction in lung injury and improvement in barrier function. These studies will increase our understanding of the pathogenesis and treatment of ARDS, improve lung health, and ultimately decrease cardiovascular complications.
|Program type||Predoctoral Fellowship|
|Effective start/end date||01/01/2020 → 12/31/2021|