With the execution of the SAVE programme we identify Piezo1 as a new molecular player linking mechanical stimuli, such as blood flow, to Notch activation and vascular remodelling. To do so, with a peristaltic pump, we tried to mimic the force created by the passage of blood flow on microvascular endothelial cells (HMvECs) or we cultured the cells in presence of a Piezo1 activator called Yoda1. We demonstrated that activation of Piezo1 by Yoda1 or shear stress resulted in increased intracellular Ca2+; activation of ADAM10, a metalloprotease involved in Notch signalling stimulation; upregulation of Notch target genes i.e. Delta-like 4 (DLL4), Hairy and enhancer of split1 (HES1) and Hairy/enhancer-of-split related with YRPW motif protein1 (HEY1) and increase of NICD release. When Piezo1 was depleted by transfecting HMvECs with siRNA targeting Piezo1, all Yoda1 and shear stress effects were suppressed. We also tried to ablate the expression of Piezo1 specifically in endothelial cells in embryos and neonatal pups in order to assess AVMs in the brain, retina and heart. However, the high lethality due to tamoxifen injection (used to inducibly disrupt the Piezo1 gene) in animals of a such young age brought us to eventually end these experiments. In order to investigate the biological importance of these molecular interactions in vivo, we analysed the expression of Notch members and arterial venous makers in freshly isolated liver endothelial cells. We were able to show that specific ablation of Piezo1 in liver endothelial cells was reflected in a decrease of Notch member expression (Hes1, Dll4, Hey1, HeyL and Jag1) and arterial marker expression Efnb2. Altogether these results identify a previously unrecognised determinant of vascular morphology downstream of shear stress, the Piezo1-Notch1 axis and were recently published in Elife journal.
In order to exploit and disseminate the results of this research, the experienced researcher (ER), Dr Caolo has presented her data in scientific conferences such as the “Cardio Metabolic Retreat” held in Ullswater (England, UK). The ER also regularly attended the weekly department seminars organized at LICAMM.
As mentioned above, the data obtained with the execution of the SAVE fellowship have been successfully published in Elife scientific journal.
In order to generate possible media interest in outreach journals and local newspapers, Dr Caolo communicated the research outcome through the LICAMM press office. The publication of this work was also mentioned on the LICAMM eNewsletter and Leeds School of Medicine twitter account, and on Vincenza’s twitter and Linkedin accounts.
