(556.29) Higher Levels of Shear Stress Downregulate Endothelin-1 mRNA Expression

Poster Board Number: E121

Carmen Rodriguez (The University of Texas at El Paso), Mario Garcia (The University of Texas at El Paso), Shelsea Cabral (The University of Texas at El Paso), Daniel Conde (The University of Texas at El Paso), Alvaro Gurovich (The University of Texas at El Paso, The University of Texas at El Paso)

Background

Physical inactivity has been shown to be a risk factor in the development of endothelial dysfunction. Endothelin-1 (EDN-1), a potent vasoconstrictor contributes to the pathogenesis of cardiovascular disease. Exercise-induced endothelial shear stress (ESS) is a mechanical stimulus caused by alterations in blood flow patterns that regulates vascular function. Although it has been reported that higher levels of ESS may act as a protective mechanism to prevent vascular dysfunction, the role of pulsatile exercise-induced ESS with varying exercise intensities has not been explored. Therefore, the purpose of this study was to determine the effects of pulsatile exercise-induced ESS based on in vivo exercise intensity on EDN-1 expression.

Methods

Commercially available human umbilical vein endothelial cells (HUVEC; Sigma-Aldrich, St Louis, MO) were cultured until 90–100% confluence. Exercise-induced ESS in vivo was obtained from our previous reports. Cultured HUVEC cells were exposed to pulsatile resting ESS (18 dynes/cm2) for 2 hours, followed by 1 hour at resting ESS, low-intensity exercise-induced ESS (35 dynes/cm2), moderate exercise-induced ESS, or high-intensity exercise-induced ESS (75 dynes/cm2) on a closed circuit pump and channeled slide (Ibidi pump system (PumpControl Software 1.5.4) and slides, Ibidi Inc., Fitchburg, WI). A set of cells were exposed to physiologically low shear stress levels (10 dynes/cm2) for 3 hours as a control. Total RNA was extracted and reverse transcribed followed by measurement of EDN-1 mRNA expression via qRT-PCR. qRT-PCRs were performed in duplicates and changes in gene expression were calculated using the ΔΔ-CT method with GAPDH used as the normalizing control gene. Statistical analysis was performed using graphpad prism 8 software (Graphpad Software.). Significance was considered at plt;0.05.

Results

EDN-1 mRNA expression was significantly downregulated following low and high intensity exercise-induced ESS compared to resting conditions (plt;0.05). Moderate intensity exercise induced ESS showed a trend downregulation in EDN-1 mRNA expression compared to resting conditions (plt;0.10).

Conclusions

Our data suggests that higher levels of pulsatile exercise-induced ESS are needed to suppress mRNA expression of EDN-1. Although moderate intensity exercise induced ESS showed only a trend difference in mRNA expression compared to resting conditions, we have previously reported that moderate exercise-induced ESS was shown to upregulate endothelial nitric oxide gene expression, a key vasodilatory enzyme that may prevent vascular dysfunction.

Research reported in this publication was supported by the National Institute Of General Medical Sciences of the National Institutes of Health under Award Number
SC2GM140952. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.



Endothelin-1 mRNA expression after resting conditions and 3 intensities of exercise-induced endothelial shear stress in vitro. (*: p<0.05 Low and High vs. Resting, ‡: p<0.10 Moderate vs. Resting)