Project Summary/Abstract Pulmonary lymphangioleiomyomatosis (LAM) is a rare lung disease caused by inactivating mutations in the tuberous sclerosis complex (TSC1/TSC2) gene which results in constitutive activation of the mechanistic target of rapamycin (mTOR) pathway. LAM manifests with diffuse parenchymal cysts complicated by secondary spontaneous pneumothorax, chylous pleural effusions and renal angiomyolipoma. In addition, a subset of LAM patients also develops pulmonary vascular remodeling and pulmonary hypertension. More recently, mTOR has been implicated in other proliferative pulmonary diseases including chronic obstructive lung disease (COPD), idiopathic pulmonary fibrosis (IPF) and pulmonary arterial hypertension (PAH). Despite the growing importance of mTOR activation in pulmonary diseases, the effects of mTOR hyperactivation on pulmonary cells remains incompletely understood. To study the effects of mTOR activation on pulmonary vascular remodeling, I will utilize a novel mouse model with tsc2 deletion as well as single cell RNA sequencing of human LAM lungs. I have found pulmonary vascular remodeling in the tsc2-null mice that mirrors histopathological findings in human LAM. Moreover, our lab recently found that LAM cells hijack the lung transcriptome leading to WNT pathway upregulation in the LAM lung. This proposal will examine how WNT activation in mTOR hyperactivated lungs contributes to pulmonary vascular remodeling with transgenic mice created by the cross of our novel tsc2-null (mTOR activated) mouse with Ctnnb1 (β-catenin) WNT pathway-activated mouse lines. This project will expand my training to include key methods and concepts in cellular crosstalk and signaling. My training will comprise of individualized mentorship, coursework/workshops in flow cytometry, training in bioinformatics and animal models. My training will take place under the sponsorship of Dr. Vera Krymskaya, a leader in LAM research. The Krymskaya lab was the first to establish human LAM cell cultures to demonstrate efficacy of rapamycin for inhibition of mTORC1 and abrogating LAM cell growth. This work will be conducted at the University of Pennsylvania, a world-class research institution with a rich intellectual environment, collaborative investigators and extensive resources for the pursuit of biomedical research. Together, the research and training plans proposed herein will facilitate a better understanding of the pulmonary microenvironment and endothelial-mesenchymal crosstalk while preparing me for my future career as an independent investigator in the field of pulmonary biology.