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A7144 - Cigarette Smoke Condensate Induces the Glycolysis and Pentose Phosphate Pathways in Normal Airway Epithelial Cells
Author Block: X. Ji; Georgia State University, Atlanta, GA, United States.
Introduction: COPD is the third leading cause of death in the US. Patients with advanced COPD often suffer from sputum production, shortness of breath and a productive cough. To significantly reduce the deaths from this disease, more accurate and reliable strategies are urgently needed to detect the disease early and to offer ways of preventing progression beyond smoking cessation efforts. Our preliminary proteomic analysis of the airway epithelium from patients with or without COPD points towards early metabolic reprogramming of bronchial epithelial cells. Some of the rate-limiting enzymes such as G6PD and LDHA are potential targets for early steps in COPD development because inhibition of their function does not affect the normal airway epithelial cell metabolism. We propose to test the hypothesis that cigarette smoking induces metabolic reprogramming in the airway epithelium and promotes the development of COPD. METHODS: First of all, we generated the cells by exposing normal airway epithelial cells to cigarette smoke condensate (CSC) for more than 7 months. Then we tested the expression of enzymes identified by proteomics in CSC long-term exposure cells. After that, we investigated the metabolic status of these cells, by using [1, 2-13C2] glucose tracer to investigate metabolic flux analysis to quantify intracellular fluxes. Last, we screened the specific metabolic signature of smoking by using LC-MS based untargeted metabolomics analysis. RESULTS: We confirmed the metabolic enzymes were upregulated based on western blotting analysis in normal airway epithelial cells after long-term cigarette smoking exposure such as G6PD and LDHA. We found that long-term exposure to CSC increased glucose consumption and lactate production compared to the control, suggestive of the Warburg effect. Our stable isotope metabolomics analysis demonstrated that 7 months exposure to CSC increases glycolysis and pentose phosphate pathways. In addition, we found that glutamine reductive carboxylation and lipid biogenesis were induced. Using untargeted LC-MS analysis we found that fatty acid biosynthetic pathway, vitamin E metabolism, and aspartate metabolism were specific metabolic signature of cigarette smoking. CONCLUSION: Our results in vitro model strongly suggest profound metabolic reprogramming such as glycolysis pathways and pentose phosphate pathway. Further investigation into the mechanism of transformation may help in answering fundamental questions pertaining to how glutamate/cystine exchange contributes to COPD development and progression and also in establishing glutamine metabolism as a potential novel therapeutic target in COPD. This work was supported by FAMRI foundation “METABOLIC REPROGRAMMING IN PATIENTS WITH COPD”, YCSA 2015