Abstract Body (Do not enter title and authors here): Background: Hyperlipidemia and vascular inflammation, two major drivers of atherosclerosis, are both linked to endothelial cell (EC) dysfunction. While EC dysfunction contributes to vascular inflammation, it is often viewed as a consequence of hyperlipidemia. We previously identified Argonaute 1 (AGO1), a core component of the RNA-induced silencing complex, as a regulator of angiogenesis and metabolic homeostasis. In this study, we tested the effect of endothelial AGO1 inhibition on a model of hyperlipidemia and atherosclerosis.
Methods:
EC-specific AGO1 knockout (EC-AGO1-KO) and wildtype mice were subjected to pro-atherosclerotic models induced by AAV9-PCSK9 and a western diet, or carotid artery ligation. Metabolic and vascular phenotyping and gene expression analyses were performed. In human liver sinusoidal ECs (HLSECs) and human aortic ECs (HAECs), AGO1 was knocked down using antisense oligos (ASO), followed by assays for inflammatory responses (qPCR, RNA-seq, ELISA, and monocyte adhesion). Mechanistic studies included Cut&Tag sequencing, and chromatin immunoprecipitation assays, and EC-hepatocyte co-cultures. Therapeutic effect of AGO1 inhibition was assessed using lipid nanoparticle (LNP)-delivered ASO in mice.
Results:
EC-AGO1-KO mice exhibited markedly improved plasma lipid profiles, reduced hepatic steatosis, inflammation, and fibrosis, and significantly attenuated atherosclerosis across the aorta. AGO1 inhibition suppressed the inflammatory responses of ECs, evidenced by decreased pro-inflammatory gene expression, cytokine production, and monocyte adhesion. In co-culture models, EC-AGO1-inhibition enhanced hepatocyte lipid metabolism. Mechanistically, AGO1 localized to the nucleus in ECs, and through a non-canonical mechanism, acted as a transcriptional coactivator of NF-κB, promoting p65 binding to the pro-inflammatory gene promoters including ICAM1 and THBS1. LNP-delivered AGO1-ASO improved hyperlipidemia, liver function, and atherosclerosis without detectable hepatotoxicity.
Conclusions:
Endothelial AGO1 promotes vascular inflammation and liver dysfunction via a non-canonical mechanism involving transcriptional coactivation of NF-κB. Inhibition of EC-AGO1 offers dual therapeutic benefits—improving lipid metabolism and suppressing vascular inflammation—highlighting endothelial AGO1 as a promising therapeutic target for atherosclerosis and cardiometabolic diseases.