Microskeletal stiffness promotes aortic aneurysm by sustaining pathological vascular smooth muscle cell mechanosensation via Piezo1

Mechanical overload of the vascular wall is a pathological hallmark of life-threatening abdominal aortic aneurysms (AAA). However, how this mechanical stress resonates at the unicellular level of vascular smooth muscle cells (VSMC) is undefined. Here, we combined novel tweezers-based micromechanical system and single-cell RNA sequencing to map defective mechano-phenotype signatures of VSMC in AAA. Notably, theoretical modelling predicted that cytoskeleton alterations fueled cell membrane tension of VSMC, thereby modulating their mechanoallostatic responses which were validated by live micromechanical measurements. Mechanistically, VSMC gradually adopted a mechanically solid-like state by upregulating CSK crosslinker, α-actinin2, in the presence of AAA-promoting signal, Netrin-1, thereby directly powering the activity of mechanosensory ion channel Piezo1. Inhibition of Piezo1 prevented mice from developing AAA by alleviating pathological vascular remodeling. Our findings demonstrate that deviations of mechanosensation behaviors of VSMC is detrimental for AAA and identifies Piezo1 as a novel culprit of mechanically fatigued aorta in AAA. Single cell RNA-sequencing datasets of abdominal aortas from Apolipoprotein E ko mice infused with Angiotensin II (4 hashtagged samples + 1 sample + 1 pooled sample (n=3)) or PBS (3 hashtagged samples + 1 pooled sample (n=3)) for 28 days