期刊
CIRCULATION RESEARCH
卷 98, 期 8, 页码 1032-1039出版社
LIPPINCOTT WILLIAMS & WILKINS
DOI: 10.1161/01.RES.0000218782.52610.dc
关键词
angiotensin; TGF-beta; Smads; vascular fibrosis
资金
- NHLBI NIH HHS [R01 HL076661, R01HL076661] Funding Source: Medline
- NIDDK NIH HHS [P50DK-064233, P50 DK064233, R01 DK062828, R01 DK060043, R01DK062828] Funding Source: Medline
Angiotensin II (Ang II) plays a pivotal role in vascular fibrosis, which leads to serious complications in hypertension and diabetes. However, the underlying signaling mechanisms are largely unclear. In hypertensive patients, we found that arteriosclerosis was associated with the activation of Smad2/3. This observation was further investigated in vitro by stimulating mouse primary aorta vascular smooth muscle cells (VSMCs) with Ang II. There were several novel findings. First, Ang II was able to activate an early Smad signaling pathway directly at 15 to 30 minutes. This was extracellular signal-regulated kinase 1/2 (ERK1/2) mitogen-activated protein kinase ( MAPK) dependent but transforming growth factor-beta (TGF-beta) independent because Ang II-induced Smad signaling was blocked by addition of ERK1/2 inhibitor and by dominant-negative (DN) ERK1/2 but not by DN-TGF-beta receptor II (T beta RII) or conditional deletion of T beta RII. Second, Ang II was also able to activate the late Smad2/3 signaling pathway at 24 hours, which was TGF-beta dependent because it was blocked by the anti-TGF-beta antibody and DN-T beta RII. Finally, activation of Smad3 but not Smad2 was a key and necessary mechanism of Ang II-induced vascular fibrosis because Ang II induced Smad3/4 promoter activities and collagen matrix expression was abolished in VSMCs null for Smad3 but not Smad2. Thus, we concluded that Ang II induces vascular fibrosis via both TGF-beta-dependent and ERK1/2 MAPK-dependent Smad signaling pathways. Activation of Smad3 but not Smad2 is a key mechanism by which Ang II mediates arteriosclerosis.
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