Project Summary Idiopathic pulmonary fibrosis (IPF) is characterized by progressive fibrosis leading to disruption of the gas exchange unit and death within an average of four years from the time of diagnosis. A poor understanding of IPF pathogenesis, in part due to a lack of reliable human disease models, has been a major hurdle to developing effective therapies. With the advent of genome wide association studies and intensive study of familial forms of pulmonary fibrosis, dysfunction of the distal lung epithelium and in particular dysfunction of alveolar epithelial type 2 (AT2) cells has been implicated as a potential proximal disease driver. Using patient-specific induced pluripotent stem cell (iPSC)-derived AT2 cells (iAT2s) our group recently described how the inception of interstitial lung disease may result from a dysfunctional AT2 cell phenotype characterized by diminished progenitor capacity, perturbed proteostasis, mitochondrial dysfunction, and NF-κB pathway activation. Despite the progress made, critical information remains to be elucidated to allow for the development of effective mechanistic IPF therapies. This proposal aims to: 1) advance our understanding of the role of mitochondrial dysfunction in eliciting a pro-fibrotic AT2 cell phenotype, 2) understand how disease-relevant environmental insults, such as cigarette smoke exposure, contribute to this dysfunction, and 3) test its reversibility. Specifically, the role of insufficient adenosine monophosphate (AMP)-activated protein kinase (AMPK) activation in driving the AT2 cell mitochondrial dysfunction, suggested by our preliminary data, will be investigated and the potential of AMPK activators as IPF therapeutics will be tested both in vitro and in vivo. We test the hypothesis that mitochondrial dysfunction in genetically susceptible human AT2 cells results from insufficient AMPK activity and is exaggerated by environmental insults leading to diminished alveolar progenitor capacity, inflammatory activation, and fibrogenic mesenchymal activation. In aim 1, using patient-specific iAT2s carrying SFTPC and TERT variants we test the hypothesis that in genetically susceptible human AT2 cells impaired AMPK activity is responsible for the mitochondrial dysfunction and metabolic reprogramming that leads to downstream epithelial canonical NF-κB pathway activation. In aim 2, we quantify the relative contribution of cigarette smoke exposure, to disease mechanisms by utilizing a novel model system. Finally in aim 3, we test the hypothesis that AT2 cell mitochondrial dysfunction results in fibrogenic mesenchymal activation and leverage this in vitro human platform to test the efficacy of AMPK agonists as potential disease-modifying therapeutics for pulmonary fibrosis. Any compounds found to be effective in vitro are then tested in vivo in the SftpcI73T mouse model.