To address our overall hypotheses that Pulmonary vascular disease/pulmonary hypertension (PHTN) is an important component of the COPD syndrome with distinct genetic and environmental determinants, we will 1. Identify genes responsible for cigarette smoke related PHTN using a mouse model and by exposing 36 strains of mice to long-term cigarette smoke and quantifying the PHTN phenotype in each strain. Given the dense SNP map, we will perform in silico mapping to identify specific genes responsible for the phenotype. We will also perform classic QTL crosses and use bioinformatics to identify the genes. 2. We have identified high fat diet as an important environmental factor that we hypothesize aggravates cigarette smoke related PHTN. We hypothesize that the mechanism for this synergistic effect of high fat is that both high fat and smoke cause ER stress and endothelial dysfunction, interfering with NO production. Low NO + the saturated fat excess will interfere with NO-mediated nitration of the polyunsaturated fatty acid, linoleic acid (LN02), highest affinity endogenous PPARy agonist known. Impaired PPARy signaling then leads to vascular PDGF-mediated smooth muscle cell proliferation and PHTN. We will both dissect this pathway and treat mice with exogenous PPARy agonists, thiazolidinedioines (TZDs). 3. To prepare for translation in years 6- 10 we will assess vascular disease by chest CT scans in a cohort of well-characterized patients with a spectrum of airflow obstruction and emphysema. We will derive and correlate indices of pulmonary vascular disease with physiology, patient symptoms, exercise performance and biomarkers of vascular disease. In addition to anatomic parameters, CT scan data will be used in conjunction with computational fluid dynamic tools to create personalized functional models of the pulmonary circulation. With the Clinical Core, we will also recruit a cohort of patients with COPD who will undergo right heart catheterizations (along with PFTs, echocardiography, exercise testing and chest CT) both to validate our findings and to test the hypothesis that vascular characteristics extracted from chest CT scan will correlate with pulmonary hypertension and pulmonary vascular responsiveness.
In this project we will assess the overall hypotheses that 1. Pulmonary vascular disease/pulmonary hypertension (PHTN) is an important component of the COPD syndrome that has distinct genetic and environmental determinants and has an independent effect on symptoms and natural history, and 2. Molecular mechanisms identified in mice, are relevant to humans, and there are overiapping mechanisms involved in primary and secondary pulmonary hypertension, including COPD.
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