Longitudinal shear stress response in human aortic endothelial cells to atheroprone and atheroprotective conditions

The goal of this study was to find longitudinal transcriptional response of human aortic endothelial cells (HAECs) to pulsatile shear (PS) and oscillatory shear (OS) and compare them with the responses in human umbilical vein endothelial cells (HUVECs) [GSE103672]. PS is associated with an atheroprotective endothelial phenotype, while OS is associated with an atheroprone endothelial phenotype. Using RNASeq method (single-ended 75-bp sequencing on Illumina Hi-seq 4000 instrument), we measured the transcriptional response at 3 time-points (1, 4, and 24 hrs) under PS and OS conditions. Measurements were also taken under static condition (ST, no flow) at t = 0 hr. Three replicates were used for each condition/time-point. Our results indicate that the responses of HAECs and HUVECs are qualitatively similar for endothelial-function relevant genes and several important pathways with a few exceptions, thus demonstrating that HUVECs can be used as a model to investigate the effects of shear on arterial ECs, with some reservations. Our findings show that HAECs exhibit an earlier response or faster kinetics as compared to HUVECs. The comparative analysis in this study offers new insights into the mechanisms of common and disparate stress responses across these two endothelial cell types. Overall design: HAECs (Cell Applications Cat# 03405A) were cultured in endothelial growth medium (Cell applications Cat#211-500) with 100 U/mL penicillin-streptomycin. Pulsatile shear (PS) and oscillatory shear (OS) flows were applied to ECs with shear stresses of 12 ± 4 dyn/cm2 and 0.5 ± 4 dyn/cm2, respectively. Samples for RNA sequencing analysis were collected at 1, 4, and 24 hrs after exposure to shear. For static condition (ST), samples were collected at t = 0 hr under no flow. Three biological replicates were collected for each time point and for each shear condition. Total RNA was extracted from ECs, processed and sequenced on the Illumina HiSeq 4000 75-bp single-end reads platform.