BS14 c-Rel drives atherosclerosis at sites of disturbed blood flow by activating inflammatory and proliferative transcriptional programmes in endothelium

IntroductionAtherosclerosis is an inflammatory disease that develops preferentially at bends and branches of the vasculature exposed to disturbed flow and low shear stress (LSS). Shear stress modifies endothelial cell (EC) function by regulating proliferation, inflammation and other fundamental processes. Shear stress alters multiple transcriptional programs, including those regulated by the NF-κB family of transcription factors. Although some members of the NF-κB pathway are known to respond to shear, the influence of haemodynamics on the c-Rel NF-κB subunit and its role in atherogenesis are unknown, and are a focus of the current study.MethodsC57BL/6 wildtype and c-Rel knockout mice were used to quantify the expression of c-Rel, the inflammatory protein E-selectin, and EC proliferation at LSS and high shear stress (HSS) regions of the aorta. To establish the role of c-Rel in atherosclerosis, C57BL/6 wildtype and c-Rel knockout mice were treated with AAV-PCSK9 and fed a high fat diet for 6 weeks. Plaque burden was quantified using Oil Red O. In vitro studies were performed using human umbilical vein EC (HUVEC) or human coronary artery EC (HCAEC) exposed to LSS or HSS. c-Rel was silenced using siRNA and EC proliferation and inflammation were measured by PCNA staining and qRT-PCR, respectively. Gene expression was studied using a microarray (ClariomTM S).ResultsEn face staining of murine aortas revealed a striking enrichment of c-Rel at LSS regions (P