Effect of chronic cigarette smoking on human microvascular endothelial cell metabolism and function

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PROJECT SUMMARY/ABSTRACT This is an 18-month research proposal which will allow the applicant to develop an academic research career in Pulmonary Medicine. The applicant is currently a fellow in Pulmonary Sciences and Critical Care Medicine at the University of Colorado/National Jewish Health. Dr. Irina Petrache, an established physician-scientist with expertise in emphysema, lung injury and repair, lung vascular biology, and sphingolipid signaling, will be the applicant's primary mentor and sponsor. Dr. Karina Serban, a physician scientist with expertise in lung innate immune responses, monocyte-endothelial interactions, and alpha 1 antitrypsin deficiency, will be the co-mentor. The proposed research will investigate the mechanisms by which chronic cigarette smoking (CS) impairs the ability of human lung microvascular endothelial cells (HLMVEC) to undergo proper homeostatic and stress- induced autophagy (a survival and reparative process) and perform angiogenesis (required for injury repair). This mechanism has significant clinical implications, since HLMVEC are essential components of the alveolar membrane required for gas exchange, host defense, and injury repair. The scientific premise of the application relies on the key role of sphingosine-1 phosphate (S1P) signaling via S1P receptor 1 (S1P1) to ensure LMVEC survival, proliferation, and barrier function. Robust published and preliminary data from the primary sponsor's laboratory show that augmenting the S1P-S1P1 signaling pathway protects LMVECs from the detrimental effects of acute CS exposure. However, the effect of chronic CS exposure on LMVEC survival and function has not yet been defined. The applicant hypothesizes that HLMVEC develop maladaptive changes following chronic CS exposure, characterized by impaired autophagy and weakened angiogenesis due to diminished S1P1 signaling, which can be reversed by augmenting S1P-S1P1 signaling. The applicant will isolate and culture primary HLMVEC from de-identified human donor lungs with a history of chronic smoking or from lifelong nonsmokers and study differences in baseline S1P-S1P1 signaling and the quality of their repair responses (autophagy and tube formation, a surrogate of angiogenesis) to homeostatic and stress conditions. Finally, she will determine the dependency of these functions on intact S1P-S1P1 signaling by gain and loss of function of enzymes and receptors. The proposed project will be an important step in defining a specific and novel mechanism of chronic CS-induced LMVEC injury and dysfunction, and therefore may inform the development of therapies to treat devastating diseases such as emphysema and pulmonary hypertension secondary to COPD. The applicant will learn a large array of translational research skills and plans to use the results from the proposed project will form the basis of her future research grants as an independent researcher, including the K08 award. The applicant has strong support from her mentors, her research advisory committee, and the Division.