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Updated: Jul 29, 2026
Subcutaneous Angiotensin II Infusion using Osmotic Pumps Induces Aortic Aneurysms in Mice
Published on: September 28, 2015
The Nonproteolytic Intracellular Domain of Membrane-Type 1 Matrix Metalloproteinase Coordinately Modulates Abdominal
Michele Silvestro1, Cristobal F Rivera1, Dornazsadat Alebrahim1
1Division of Vascular and Endovascular Surgery, Department of Surgery (M.S., C.F.R., D.A., J.V., M.Y.P., C.T., Z.H., R.S.T., A.L.Z., D.J.M., D.B., B.R.).
Background:
MT1-MMP (membrane-type 1 matrix metalloproteinase, MMP-14) is a transmembrane-anchored protein with an extracellular proteinase domain and a cytoplasmic tail devoid of proteolytic functions but capable of mediating intracellular signaling that regulates tissue homeostasis. MT1-MMP extracellular proteolytic activity has been shown to regulate pathological remodeling in aortic aneurysm and atherosclerosis. However, the role of the nonproteolytic intracellular domain of MT1-MMP in vascular remodeling in abdominal aortic aneurysms (AAA) is unknown.
Methods:
We generated a mutant mouse that harbors a point mutation (Y573D) in the MT1-MMP cytoplasmic domain that abrogates the MT1-MMP signaling function without affecting its proteolytic activity. These mice and their control wild-type littermates were subjected to experimental AAA modeled by angiotensin II infusion combined with PCSK9 (proprotein convertase subtilisin/kexin type 9) overexpression and high-cholesterol feeding.
Results:
The mutant mice developed more severe AAA than the control mice, with concomitant generation of intraaneurysmal atherosclerotic lesions and dramatically increased macrophage infiltration and elastin degradation. Aortic lesion-associated and bone marrow-derived macrophages from the mutant mice exhibited an enhanced inflammatory state and expressed elevated levels of proinflammatory Netrin-1, a protein previously demonstrated to promote both atherosclerosis and AAA.
Conclusions:
Our findings show that the cytoplasmic domain of MT1-MMP safeguards from AAA and atherosclerotic plaque development through a proteolysis-independent signaling mechanism associated with Netrin-1 expression. This unexpected function of MT1-MMP unveils a novel mechanism of synchronous onset of AAA and atherogenesis and highlights its importance in the control of vascular wall homeostasis.
