In:
Circulation Research, Ovid Technologies (Wolters Kluwer Health), Vol. 118, No. 3 ( 2016-02-05), p. 388-399
Abstract:
Aortic aneurysm is a life-threatening cardiovascular disorder caused by the predisposition for dissection and rupture. Genetic studies have proved the involvement of the transforming growth factor-β (TGF-β) pathway in aortic aneurysm. Smad4 is the central mediator of the canonical TGF-β signaling pathway. However, the exact role of Smad4 in smooth muscle cells (SMCs) leading to the pathogenesis of aortic aneurysms is largely unknown. Objective: To determine the role of smooth muscle Smad4 in the pathogenesis of aortic aneurysms. Methods and Results: Conditional gene knockout strategy combined with histology and expression analysis showed that Smad4 or TGF-β receptor type II deficiency in SMCs led to the occurrence of aortic aneurysms along with an upregulation of cathepsin S and matrix metallopeptidase-12, which are proteases essential for elastin degradation. We further demonstrated a previously unknown downregulation of matrix metallopeptidase-12 by TGF-β in the aortic SMCs, which is largely abrogated in the absence of Smad4. Chemotactic assay and pharmacologic treatment demonstrated that Smad4-deficient SMCs directly triggered aortic wall inflammation via the excessive production of chemokines to recruit macrophages. Monocyte/macrophage depletion or blocking selective chemokine axis largely abrogated the progression of aortic aneurysm caused by Smad4 deficiency in SMCs. Conclusions: The findings reveal that Smad4-dependent TGF-β signaling in SMCs protects against aortic aneurysm formation and dissection. The data also suggest important implications for novel therapeutic strategies to limit the progression of the aneurysm resulting from TGF-β signaling loss-of-function mutations.
Type of Medium:
Online Resource
ISSN:
0009-7330
,
1524-4571
DOI:
10.1161/CIRCRESAHA.115.308040
Language:
English
Publisher:
Ovid Technologies (Wolters Kluwer Health)
Publication Date:
2016
detail.hit.zdb_id:
1467838-X
Permalink
