Institute of Laboratory Medicine, Clinical Chemistry and Molecular Diagnostics, University Leipzig, Leipzig, Germany.
Atherosclerosis. 2011 Feb;214(2):264-70. doi: 10.1016/j.atherosclerosis.2010.06.029. Epub 2010 Jun 23.
The pathophysiology underlying the chromosome (Chr) 9p21 locus of atherosclerosis susceptibility is presently unknown. Here, we sought to determine whether protein coding genes in the Chr9p21 region, i.e. cyclin-dependent kinase inhibitors CDKN2B (p15(INK4b)), CDKN2A (p16(INK4a), p14(ARF)) and methylthioadenosine phosphorylase (MTAP) were expressed in human atherosclerotic lesions and whether expression was correlated with lesion composition.
Protein expression of p15(INK4b), p16(INK4a), p14(ARF) and MTAP was demonstrated by immunostaining in normal and atherosclerotic coronary arteries and co-localized with CD68 and smooth muscle alpha-actin positive cells. Quantitative RT-PCR in human endarteryectomy specimens (n = 57) revealed increased p16(INK4a) and decreased MTAP expression in macrophage-rich lesions (P<0.001 and P = 0.007, respectively). Functional studies suggest that decreased MTAP expression in macrophage-rich lesions might be mediated through down-regulation by TNF-alpha. No clear association of p15(INK4b), p16(INK4a), p14(ARF), and MTAP expression in plaque tissue with Chr9p21 haplotypes was found. The latter finding was corroborated by the lack of correlation of RNA expression of 9p21-regulated transcripts EU741058 and NR_003529 of antisense non-coding RNA in the INK4 locus (ANRIL) with mRNA expression of these genes. In contrast, ANRIL DQ485454 which is not genetically determined by the 9p21 genotype was significantly correlated with MTAP expression (P = 0.01).
CDKN2B (p15(INK4b)), CDKN2A (p16(INK4a), p14(ARF)), and MTAP are abundantly expressed in atherosclerotic lesions. While expression levels showed no clear association with Chr9p21 genotype, association of high p16(INK4a) and low MTAP expression with a less stable plaque phenotype suggests a more general role of these proteins in atherogenesis.
目前尚不清楚动脉粥样硬化易感性染色体（Chr）9p21 位点的病理生理学基础。在这里，我们试图确定 Chr9p21 区域的蛋白编码基因，即细胞周期蛋白依赖性激酶抑制剂 CDKN2B（p15（INK4b））、CDKN2A（p16（INK4a）、p14（ARF））和甲基硫腺苷磷酸化酶（MTAP）是否在人动脉粥样硬化病变中表达，以及表达是否与病变成分相关。
通过免疫染色在正常和动脉粥样硬化的冠状动脉中证明了 p15（INK4b）、p16（INK4a）、p14（ARF）和 MTAP 的蛋白表达，并与 CD68 和平滑肌α-肌动蛋白阳性细胞共定位。对人类内膜切除术标本（n=57）的定量 RT-PCR 显示，富含巨噬细胞的病变中 p16（INK4a）表达增加，MTAP 表达减少（P<0.001 和 P=0.007）。功能研究表明，富含巨噬细胞的病变中 MTAP 表达的降低可能是通过 TNF-α的下调介导的。在斑块组织中，p15（INK4b）、p16（INK4a）、p14（ARF）和 MTAP 的表达与 Chr9p21 单倍型之间没有明显的关联。后者的发现得到了以下事实的证实：INK4 基因座（ANRIL）中受 9p21 调控的转录物 EU741058 和 NR_003529 的 RNA 表达与这些基因的 mRNA 表达之间没有相关性。相比之下，DQ485454 型 ANRIL 不受 9p21 基因型遗传决定，与 MTAP 表达显著相关（P=0.01）。
CDKN2B（p15（INK4b））、CDKN2A（p16（INK4a）、p14（ARF））和 MTAP 在动脉粥样硬化病变中大量表达。虽然表达水平与 Chr9p21 基因型没有明显关联，但高 p16（INK4a）和低 MTAP 表达与更不稳定的斑块表型相关，提示这些蛋白在动脉粥样形成中具有更普遍的作用。
