Nanda Vivek, Downing Kelly P, Ye Jianqin, Xiao Sophia, Kojima Yoko, Spin Joshua M, DiRenzo Daniel, Nead Kevin T, Connolly Andrew J, Dandona Sonny, Perisic Ljubica, Hedin Ulf, Maegdefessel Lars, Dalman Jessie, Guo Liang, Zhao XiaoQing, Kolodgie Frank D, Virmani Renu, Davis Harry R, Leeper Nicholas J
From the Departments of Surgery (V.N., K.P.D., J.Y., S.X., Y.K., D.D., K.T.N., J.D., N.J.L.), Medicine (J.M.S., N.J.L.), and Pathology (A.J.C.), Stanford University School of Medicine, CA; Department of Medicine, McGill University, Montreal, Canada (S.D.); Departments of Molecular Medicine and Surgery (L.P., U.H.) and Medicine (L.M.), Karolinska Institute, Stockholm, Sweden; and CVPath Institute, Gaithersburg, MD (L.G., X.Z., F.D.K., R.V., H.R.D.).
Circ Res. 2016 Jan 22;118(2):230-40. doi: 10.1161/CIRCRESAHA.115.307906. Epub 2015 Nov 23.
Genetic variation at the chromosome 9p21 cardiovascular risk locus has been associated with peripheral artery disease, but its mechanism remains unknown.
To determine whether this association is secondary to an increase in atherosclerosis, or it is the result of a separate angiogenesis-related mechanism.
Quantitative evaluation of human vascular samples revealed that carriers of the 9p21 risk allele possess a significantly higher burden of immature intraplaque microvessels than carriers of the ancestral allele, irrespective of lesion size or patient comorbidity. To determine whether aberrant angiogenesis also occurs under nonatherosclerotic conditions, we performed femoral artery ligation surgery in mice lacking the 9p21 candidate gene, Cdkn2b. These animals developed advanced hindlimb ischemia and digital autoamputation, secondary to a defect in the capacity of the Cdkn2b-deficient smooth muscle cell to support the developing neovessel. Microarray studies identified impaired transforming growth factor β (TGFβ) signaling in cultured cyclin-dependent kinase inhibitor 2B (CDKN2B)-deficient cells, as well as TGFβ1 upregulation in the vasculature of 9p21 risk allele carriers. Molecular signaling studies indicated that loss of CDKN2B impairs the expression of the inhibitory factor, SMAD-7, which promotes downstream TGFβ activation. Ultimately, this manifests in the upregulation of a poorly studied effector molecule, TGFβ1-induced-1, which is a TGFβ-rheostat known to have antagonistic effects on the endothelial cell and smooth muscle cell. Dual knockdown studies confirmed the reversibility of the proposed mechanism, in vitro.
These results suggest that loss of CDKN2B may not only promote cardiovascular disease through the development of atherosclerosis but may also impair TGFβ signaling and hypoxic neovessel maturation.
9号染色体p21区域心血管风险位点的基因变异与外周动脉疾病相关，但其机制尚不清楚。
确定这种关联是动脉粥样硬化增加的继发结果，还是独立的血管生成相关机制的结果。
对人体血管样本的定量评估显示，无论病变大小或患者合并症如何，9p21风险等位基因携带者的斑块内未成熟微血管负担显著高于祖先等位基因携带者。为了确定在非动脉粥样硬化条件下是否也会发生异常血管生成，我们在缺乏9p21候选基因Cdkn2b的小鼠中进行了股动脉结扎手术。这些动物出现了严重的后肢缺血和趾自截，这是由于Cdkn2b缺陷的平滑肌细胞支持新生血管形成的能力缺陷所致。微阵列研究发现，在培养的细胞周期蛋白依赖性激酶抑制剂2B（CDKN2B）缺陷细胞中，转化生长因子β（TGFβ）信号受损，以及9p21风险等位基因携带者的血管系统中TGFβ1上调。分子信号研究表明，CDKN2B的缺失会损害抑制因子SMAD-7的表达，从而促进下游TGFβ的激活。最终，这表现为一种研究较少的效应分子TGFβ1诱导因子-1的上调，该因子是一种已知对内皮细胞和平滑肌细胞具有拮抗作用的TGFβ调节剂。双重敲低研究在体外证实了所提出机制的可逆性。
这些结果表明，CDKN2B的缺失不仅可能通过动脉粥样硬化的发展促进心血管疾病，还可能损害TGFβ信号和缺氧新生血管的成熟。
