Endothelial Integrin-Linked Kinase (ILK) Deficiency Promotes Endothelial Activation and Cardiovascular Dysfunction via Receptor Interacting Protein Kinase-1 (RIPK1) Enriched-Extracellular Vesicle Signalling.

Integrin-linked kinase (ILK) maintains endothelial homeostasis by supporting endothelial nitric oxide synthase activity and restraining vascular inflammation. Although endothelial ILK loss is linked to vascular and cardiac disease, the mechanisms driving progression remain unclear. We hypothesized that extracellular vesicles (EVs) released by ILK-deficient endothelial cells propagate endothelial activation and cardiac dysfunction. In endothelial-specific ILK conditional knockout mice, ILK loss induced rapid endothelial activation, marked by increased iNOS, VCAM-1 and ICAM-1, followed by perivascular macrophage accumulation and chronic cardiac inflammation. In vitro, ILK-deficient endothelial cells exhibited barrier dysfunction, NF-κB activation and increased chemokine production. EVs derived from ILK deficient cells were enriched in pro-inflammatory cargo, including receptor-interacting protein kinase 1 (RIPK1), and transferred the activation phenotype to naïve endothelial cells. RIPK1 inhibition in recipient cells or RIPK1 silencing in donor cells abolished EV-induced activation, thereby confirming a necessary role for RIPK1. Endothelial ILK-deficient mice also exhibited increased circulating EVs enriched in endothelial activation markers and RIPK1. Transfer of these EVs to wild type mice induced coronary endothelial activation, macrophage recruitment, microvascular remodelling, cardiac fibrosis, and ventricular dysfunction mimicking the phenotype of the donor mice. RIPK1-dependent inflammatory effects were similarly observed with EVs from atherosclerotic ApoE