A mechano-dependent senescence associated secretory phenotype triggers the recruitment of endothelial and immune cells by Cerebral Cavernous Malformation 2 deficient endothelial cells

Cerebral Cavernous Malformations (CCM) is a cerebrovascular disease in which stacks of dilated haemorrhagic blood-filled capillaries form focally in the brain. Endothelial loss-of-function mutations on any of the three CCM genes (CCM1-3) are responsible for the familial form of the disease. Whether and how the defective mechanotransduction, inflammatory response and mosaic state characteristic of these lesions interplay to sustain the progression of CCM diseases is unknown. Here, we show that CCM1- and CCM2-silenced endothelial cells enter into a senescence associated with secretory phenotype (SASP) that they use to invade the extracellular matrix and attract surrounding wild-type endothelial and immune cells. Further, we demonstrate that this SASP is driven by the mechanical and molecular disorders provoked by ROCKs dysfunctions when CCM2 is lost. This discovery reconciles all the known dysregulated traits of CCM1/2-deficient endothelial cells into a unique mechano-dependent SASP that links perturbed cellular mechanics to microenvironment remodelling and long-range activation of WT endothelial and immune cells. RNA-seq analysis of monolayers of HUVEC silenced for CCM2 and/or ROCK1 or ROCK2 (3 replicates per condition; 6 conditions. NT used as the reference sample).