Effect of a Single Bout of Aerobic Exercise on NF-κB in Peripheral Blood Mononuclear Cells

Abstract

Lipemia and systemic inflammation are involved in the development of metabolic disorders including atherosclerosis, Type 2 diabetes, and metabolic syndrome. Nuclear factor-κB (NF-κB), elevated by circulating lipids, has long been recognized as a key pro-inflammatory transcription factor involved in the pathogenesis of these and other diseases. Despite the known anti-inflammatory and lipid lowering effects of exercise, its effect on NF-κB remains unclear. PURPOSE: The aim of this study was to determine the effect of a single bout of aerobic exercise on fasting NF-κB phosphorylation in circulating peripheral blood mononuclear cells (PBMCs). METHODS: Healthy male subjects (n=9, age=24±6, BMI=23±4, %Fat=19±8) reported to the laboratory following an overnight fast (12-14h) on two separate occasions for blood draws. The afternoon prior (16-18h) to one of the morning visits participants completed an acute bout of aerobic exercise (45-min of cycling at 70-75% of VO2peak). Physical activity was monitored throughout the study and, with the exception of the prescribed exercise, participants were instructed to remain sedentary for the 24h prior to each visit. Fasting triglycerides (TG) were quantified using an in vitro assay and PBMCs were isolated using the Ficoll Paque Plus method. Cells were lysed and equal protein was separated by SDS-PAGE. Phosphorylated NF-κB p65 (Ser536) protein, as an indicator of activation, was determined via Western blot and analyzed with Image J software. Statistical analysis was performed between the control and exercise sessions using a paired T-test and linear regression was used to identify significant correlations. RESULTS: A single bout of acute aerobic exercise, performed 16-18h prior, significantly decreased fasting expression of phosphorylated NF-κB (p-NF-κB) in PBMCs (27% decrease, p=0.01). The exercise bout also tended to reduce fasting plasma TG levels (13% decrease, p=0.07). Age was significantly associated with the exercise-induced reduction in p-NF-κB (r=0.70, p=0.04). CONCLUSION: An acute bout of aerobic exercise decreased fasting NF-κB phosphorylation in circulating PBMCs, which may be related to reductions in triglycerides. Ongoing analyses will further describe molecular changes involved in the regulation of NF-κB signaling.