Nicotine Treatment Resulted in Decreased Protein Expression of Prorenin and Soluble Prorenin Receptor in 3T3-L1 cells.

Over 36.5% of the United States population is affected by obesity, which is a major contributing factor to the rise of hypertension and cardiovascular disease. Furthermore, the CDC reports that over 16 million Americans suffer from nicotine-related diseases. Nicotine consumption causes an increase in blood pressure and a decrease in adipogenesis. The prorenin receptor (PRR) and its soluble form (sPRR) are newly discovered components of a blood pressure regulatory pathway, the renin angiotensin system (RAS), and are upregulated during times of obesity. Currently, there is no research to understand the contrasting relationship between nicotine and PRR. Therefore, in this present study, we aimed to determine whether nicotine regulates blood pressure through an adipocyte PRR-dependent. 3T3-L1 cells were grown to confluence and differentiated over 8 days. On day 8, cells were treated with nicotine dose response treatments: vehicle (water), 0.01 µM nicotine, 1 µM nicotine, or 10 µM nicotine. After 24-hour treatment, cells were collected to measure protein levels of PRR and it soluble form, sPRR. Additionally, gene expression levels of PRR, renin, 18S, furin, and S1P were measured. Media from the cells was collected after 2 hours, 4 hours, and 24 hours of incubation to measure the secretion levels of sPRR into the media. Nicotine significantly decreased PRR protein expression at 1µM (n=2) compared to vehicle treatment (n=6) (vehicle: 1.00 0.37au; 1 µM: 0.46 0.09au; p <0.05). Nicotine did not affect the gene expression of PRR but significantly decreased PRR and sPRR protein levels in a dose response manner compared to vehicle treatment (vehicle: 1.00 0.42au, n=6; 0.01 µM: 0.47 0.18au, n=4, 1uM: 0.32 0.12au, n=2; p <0.05). Nicotine did not change the expression of S1P, and furin, two enzymes involved in PRR cleavage. Finally, renin and angiotensinogen (AGT) increased significantly in differentiated adipocytes treated with nicotine compared to those treated with vehicle. Together our data indicated that nicotine influences local renin angiotensin system by post-transcriptionally down-regulating PRR and sPRR protein and by upregulating renin and AGT. Together, these data suggest that nicotine could assert its effect on blood pressure and adipogenesis via an adipocyte-PRR dependent mechanism.