Wang Mingyi, Zhao Di, Spinetti Gaia, Zhang Jing, Jiang Li-Qun, Pintus Gianfranco, Monticone Robert, Lakatta Edward G
Laboratory of Cardiovascular Science, Gerontology Research Center, National Institute on Aging/NIH, 5600 Nathan Shock Dr, Baltimore, MD 21224-6825, USA.
Arterioscler Thromb Vasc Biol. 2006 Jul;26(7):1503-9. doi: 10.1161/01.ATV.0000225777.58488.f2. Epub 2006 May 11.
To study matrix metalloproteinase 2 (MMP-2) effects on transforming growth factor-beta1 (TGF-beta1) activation status and downstream signaling during arterial aging.
Western blotting and immunostaining showed that latent and activated TGF-beta1 are markedly increased within the aorta of aged Fisher 344 cross-bred Brown Norway (30 months of age) rats compared with adult (8 months of age) rats. Aortic TGF-beta1-type II receptor (TbetaRII), its downstream molecules p-similar to mad-mother against decapentaplegic (SMAD)2/3 and SMAD4, fibronectin, and collagen also increased with age. Moreover, TGF-beta1 staining is colocalized with that of activated MMP-2 within the aged arterial wall and vascular smooth muscle cell (VSMC) in vitro, and this physical association was confirmed by coimmunoprecipitation. Incubation of young aortic rings ex vivo or VSMCs in vitro with activated MMP-2 enhanced active TGF-beta1, collagen, and fibronectin expression to the level of untreated old counterparts, and this effect was abolished via inhibitors of MMP-2. Interestingly, in old untreated rings or VSMCs, the increased TGF-beta1, fibronectin, and collagen were also substantially reduced by inhibition of MMP-2.
Active TGF-beta1, its receptor, and receptor-mediated signaling increase within the aortic wall with aging. TGF-beta1 activation is dependent, in part at least, by a concomitant age-associated increase in MMP-2 activity. Thus, MMP-2-activated TGF-beta1, and subsequently TbetaRII signaling, is a novel molecular mechanism for arterial aging.
研究基质金属蛋白酶2（MMP - 2）对动脉衰老过程中转化生长因子β1（TGF - β1）激活状态及下游信号传导的影响。
蛋白质免疫印迹法和免疫染色显示，与成年（8月龄）大鼠相比，老年（30月龄）Fisher 344杂交Brown Norway大鼠主动脉内潜伏型和激活型TGF - β1显著增加。主动脉TGF - β1Ⅱ型受体（TβRⅡ）、其下游分子磷酸化的与果蝇抗五体不全蛋白相似蛋白（SMAD）2/3和SMAD4、纤连蛋白以及胶原蛋白也随年龄增加。此外，在体外，老年动脉壁和血管平滑肌细胞（VSMC）中TGF - β1染色与激活的MMP - 2染色共定位，免疫共沉淀证实了这种物理关联。用激活的MMP - 2离体孵育年轻主动脉环或体外培养VSMC，可使活性TGF - β1、胶原蛋白和纤连蛋白表达增强至未处理老年组的水平，且MMP - 2抑制剂可消除这种作用。有趣的是，在未处理的老年主动脉环或VSMC中，抑制MMP - 2也可使增加的TGF - β1、纤连蛋白和胶原蛋白显著减少。
随着衰老，主动脉壁内活性TGF - β1、其受体及受体介导的信号传导增加。TGF - β1激活至少部分依赖于与年龄相关的MMP - 2活性的伴随性增加。因此，MMP - 2激活的TGF - β1以及随后的TβRⅡ信号传导是动脉衰老的一种新型分子机制。
