TY - JOUR TI - RIPK1 Expression Associates with Inflammation in Early Atherosclerosis in Humans and Can be Therapeutically Silenced to Reduce NF-κB Activation and Atherogenesis in Mice AU - Karunakaran Denuja AU - Nguyen My-Anh AU - Geoffrion Michele AU - Vreeken Dianne AU - Lister Zachary AU - Cheng Henry S. AU - Otte Nicola AU - Essebier Patricia AU - Wyatt Hailey AU - Kandiah Joshua W. AU - Jung Richard AU - Alenghat Francis J. AU - Mompeon Ana AU - Lee Richard AU - Pan Calvin AU - Gordon Emma AU - Rasheed Adil AU - Lusis Aldons J. AU - Liu Peter AU - Matic Ljubica Perisic AU - Hedin Ulf AU - Fish Jason E. AU - Guo Liang AU - Kolodgie Frank AU - Virmani Renu AU - van Gils Janine M. AU - Rayner Katey J. T2 - Circulation AB - Background: Chronic activation of the innate immune system drives inflammation and contributes directly to atherosclerosis. Previously, we showed that macrophages in the atherogenic plaque undergo RIPK3-MLKL-dependent programmed necroptosis in response to sterile ligands such as oxidized LDL and damage-associated patterns (DAMPs) and necroptosis is active in advanced atherosclerotic plaques. Upstream of the RIPK3-MLKL necroptotic machinery lies RIPK1, which acts as a master switch that controls whether the cell undergoes NFκB-dependent inflammation, caspase-dependent apoptosis or necroptosis in response to extracellular stimuli. We therefore set out to investigate the role of RIPK1 in the development of atherosclerosis, which is largely driven by NFκB-dependent inflammation at early stages. We hypothesize that, unlike RIPK3 and MLKL, RIPK1 primarily drives NFκB-dependent inflammation in early atherogenic lesions and knocking down RIPK1 will reduce inflammatory cell activation and protect against the progression of atherosclerosis. Methods: We examined expression of RIPK1 protein and mRNA in both human and mouse atherosclerotic lesions, and using loss-of-function approaches in vitro in macrophages and endothelial cells to measure inflammatory responses. We administered weekly injections of RIPK1 anti-sense oligonucleotides (ASO) to Apoe-/- mice fed a cholesterol-rich (Western) diet for 8 weeks. Results: We find RIPK1 expression is abundant in early-stage atherosclerotic lesions in both humans and mice. Treatment with RIPK1 ASOs led to a reduction in aortic sinus and en face lesion areas (47.2% or 58.8% decrease relative to control, p<0.01) and plasma inflammatory cytokines (IL-1α, IL-17A, p<0.05) compared to controls. RIPK1 knockdown in macrophages decreased inflammatory genes (NFκB, TNFα, IL-1α) and in vivo LPS- and atherogenic diet-induced NF-κB activation. In endothelial cells, knockdown of RIPK1 prevented NF-κB translocation to the nucleus in response to TNFα, where accordingly there was a reduction in gene expression of IL1B, E-selectin and monocyte attachment. Conclusions: We have identified RIPK1 as a central driver of inflammation in atherosclerosis by its ability to activate the NF-κB pathway and promote inflammatory cytokine release. Given the high levels of RIPK1 expression in human atherosclerotic lesions, our study suggests RIPK1 as a future therapeutic target to reduce residual inflammation in patients at high risk of coronary artery disease. DO - 10.1161/CIRCULATIONAHA.118.038379 DP - ahajournals.org (Atypon) VL - 0 IS - 0 J2 - Circulation UR - https://www.ahajournals.org/doi/10.1161/CIRCULATIONAHA.118.038379 Y2 - 2020/11/23/17:59:37 ER -