Alpha7 Nicotinic Acetylcholine Receptor Mediates Chronic Nicotine Inhalation-Induced Cardiopulmonary Dysfunction

Purpose: The goal of this study is to compare the effects of inhaled nicotine on aortic gene expression and the role of the alpha7 nicotinic acetylcholine receptor (alpha7-nAChR) in mediating the nicotine effects. Methods: WT and alpha7-nAChR knockout (KO) mice at 5-month of age were exposed to nicotine vapor or room air for a total of 12 weeks. Total RNA was extracted from thoracic aortas using RNeasy Plus mini kit followed by library preparation using SMART-Seq v4 Ultra Low Input RNA Kit. Illumina next generation sequencing was performed using the NextSeq 500 system with the high output flow cell (up to 800 M paired end reads). Results: A total of 179 differentially expressed genes (149 upregulated and 30 downregulated, adjusted P-value < 0.1) were found in thoracic aortas from WT mice exposed to nicotine vapor compared to those exposed to room air. In contrast, only 7 non-overlapping genes were found to be differentially expressed in alpha7-nAChR KO mice exposed to nicotine compared to the air controls. Conclusions: Our study suggests that nicotine-induced changes in vascular gene expression is largely mediated by the alpha7-nAChR. Thoracic aorta gene expression of 8-month old WT and alpha7-nAChR KO mice with prior exposure to nicotine vapor or room air for 12 weeks.