Acute Exercise-induced Endothelial Shear Stress Activates Nos3 Mrna Translation In Vitro

Endothelial nitric oxide synthase (eNOS), a protein encoded by the NOS3 gene, synthesizes nitric oxide (NO) to maintain and regulate vascular tone. In vivo studies show a positive correlation between physical activity and eNOS and NOS3 expression after 4 to 8-week interventions. However, the acute effects of exercise have not been explored. PURPOSE: To determine the acute effects of different exercise intensities on eNOS and NOS3 expression using an in vitro model of exercise. METHODS: Cultured human umbilical vein endothelial cells (HUVEC) were exposed to five hours of resting ESS (18 dyn/cm2, 60 pulses per minute [PPM]) and one hour of one of the experimental conditions, rest (18 dyn/cm2, 60 PPM), low (35 dyn/cm2, 100 PPM), moderate (50 dyn/cm2, 120 PPM), or high (60 dyn/cm2, 150 PPM). Cells were harvested immediately after exposure to ESS, and protein and ribosomal RNA were extracted. The eNOS expression relative to the loading control GAPDH was assessed by Western Blots. The NOS3 expression relative to the housekeeping gene GAPDH was assessed by RT-qPCR. One-way ANOVA using Tukey post hoc test (p = 0.05) was used to assess significant differences in protein expression. RESULTS: There was a significant increase in eNOS expression in HUVEC exposed to low (p = 0.021) and high-intensity (p = 0.025) ESS compared to rest ESS and a decrease in NOS3 in HUVEC exposed to low, moderate, and high-intensity ESS compared to rest ESS. CONCLUSIONS: acute exercise-induced ESS in vitro contributes to the upregulation of eNOS expression by activating the translation of NOS3 mRNA. National Institute of General Medical Sciences of the National Institutes of Health