MMPs are a family of proteolytic enzymes that degrade ECM proteins and are critical for cell migration and tissue remodeling under physiological and pathological conditions.[25] Studies have reported that MMP2 and MMP9 secreted by VSMCs play an important role in ECM degradation in aortic aneurysms and AD.[26, 27] Following Ang II administration, MMP2/9 activity—determined via an in situ MMP activity assay—was enhanced in the aorta of CCDC80−/− mice compared with WT mice (Figure S10A, B, Supporting Information). This evidence concerns the gene MMP9 and aortic aneurysm.