Mitochondrial regulation of lung development, injury and repair

Project: Research project

Description

Statement of the Problem: The acute respiratory distress syndrome (ARDS) is a devastating disorder commonly associated with pneumonia and influenza. The mortality rate is high from 30 to 45%, and there is no current effective therapy except supportive care. One novel therapeutic approach is to promote lung repair after injury has occurred, by inducing lung epithelial stem/progenitor cell populations. Little is known about how proliferation and differentiation are regulated in the epithelial stem/progenitor cells, both for homeostasis and for repair after injury. My mentor Dr. Chandel’s laboratory previously demonstrated that the mitochondrial respiratory chain is essential for the differentiation of various cells including hematopoietic stem cells. These effects are exerted through reactive oxygen species or the accumulation of mitochondrial metabolites that control epigenetic machinery, and are independent of the ATP synthetic function of mitochondria. Whether lung epithelial stem/progenitor cells are regulated by mitochondrial metabolism has not been studied. My preliminary data suggest that mitochondrial complex I is required for postnatal lung development and differentiation of lung stem/progenitor cells.
Specific Aims: The objectives of my project are to 1) investigate the mechanism by which mitochondrial complex I driven respiration is necessary and sufficient for lung development, and 2) test whether mitochondrial complex I respiration is required for the repair of influenza-induced epithelial adult lung injury.
Experimental Approach: I will deplete the mitochondrial complex I subunit, NADH:ubiquinone oxidoreductase core subunit S2 (NDUFS2) to induce mitochondrial complex I deficiency in mice. I will characterize the phenotypes of Ndufs2 null mice (Ndufs2fl/flSFTPC-Cre:R26RtdT), and perform RNA-Seq and metabolomics of alveolar epithelial cells isolated from the Ndufs2 null mice (Aim 1). Next, I will express alternative NADH dehydrogenase found in Saccharomyces cerevisiae that restores only electron transport, but not proton pumping, to evaluate which of these complex I functions is sufficient to restore the phenotype observed in the lung specific Ndufs2 null mice (Ndufs2fl/flSFTPC-Cre). Finally, using an inducible Cre system (Sftpc-CreERT2and Krt5-CreERT2), I will deplete NDUFS2 protein after influenza A infection to investigate if mitochondrial complex I is necessary for the repair of influenza-induced lung injury (Aim 2).
Significance of the results: My project will provide a new mechanistic model linking mitochondrial metabolism to lung epithelial stem/progenitor cells in the context of lung development and lung injury/repair. The activities planned in this proposal, including guidance with close mentorship, attendance of conferences, and completion of coursework in a research-intensive institutional environment, will further my continued development into an independent researcher.
StatusActive
Effective start/end date7/1/196/30/22

Funding

  • Francis Family Foundation (Agmt 3/6/19)

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Lung Injury
Stem Cells
Lung
Human Influenza
Epithelial Cells
Mentors
Electron Transport
Respiration
Electron Transport Complex I
Alveolar Epithelial Cells
Phenotype
NADH Dehydrogenase
Metabolomics
Adult Respiratory Distress Syndrome
Wounds and Injuries
Hematopoietic Stem Cells
Epigenomics
Saccharomyces cerevisiae
Protons
Cell Differentiation