Effect of shear stress on Chromatin structure

This study aimed to investigate chromatin accessibility in endothelial cells under pulsatile shear stress (PS) and Oscillatory shear stress (OS). The ATACseq signals were measured at four-time points (0, 2, 8, and 16 hr) under PS or OS. Three replicates were used for each condition and time point. HUVECS were cultured in M199 medium (Gibco) supplemented with 15% fetal bovine serum (FBS) , 1 ng/ml recombinant human fibroblast growth factor, 90 μg/ml heparin, 20 mM HEPES (pH 7.4), and 100 U/ml penicillin-streptomycin. Samples for ATAC sequencing were collected at 0, 2, 8, 16hr following exposure to shear stress. Three biological replicates were collected for each treatment and each at each time point. Following treatment, nuclei were isolated from ECs lysed in lysis buffer containing 10 mmol/L Tris-HCl, 10 mmol/L NaCl, 3 mmol/L MgCl2, and 0.1% NP-40. Resulting nuclei were incubated in 50 transposition buffer (Nextera DNA Library Preparation Kit; Illumina) and DNA samples were purified with Qiagen MinElute PCR purification kit followed by library preparation and paired-end sequencing on an Illumina NextSeq 500 sequencing platform.