Bayoglu Burcu, Arslan Caner, Gode Safa, Kaya Dagistanli Fatma, Arapi Berk, Burc Deser Serkan, Dirican Ahmet, Cengiz Mujgan
Department of Medical Biology, Cerrahpasa Medical Faculty, Istanbul University.
J Atheroscler Thromb. 2014;21(7):659-71. doi: 10.5551/jat.21774. Epub 2014 Mar 5.
The INK4b-ARF-INK4a locus in the chromosome 9p21 region is known to play an important role in the development of atherosclerosis. The INK4/ARF transcript p16(INK4a) inhibits the activity of the cyclin-dependent kinases CDK4/CDK6 and arrests cell-cycle progression. CDK inhibitors also regulate G1/S phase progression in vascular smooth muscle cells(VSMCs) and may modulate the early stages of atherosclerosis. Therefore, we aimed to study the expression of the INK4/ARF locus genes CDKN2A and CDKN2BAS in order to examine the p16(INK4a) protein expression and the level of cell proliferation in carotid plaques and saphenous tissue samples.
A total of 50 patients(33 symptomatic subjects and 17 asymptomatic subjects) with carotid atherosclerosis CA) were studied. The CDKN2A and CDKN2BAS gene expression levels were determined using quantitative real-time polymerase chain reaction(qRT-PCR). All tissue sections were also analyzed for the p16(INK4a) and proliferating cell nuclear antigen(PCNA) protein expression using immunohistochemistry(IHC).
The CDKN2A gene expression was significantly higher in the carotid plaques than in the saphenous tissues(p=0.009), whereas no such differences were observed in the CDKN2BAS transcripts(p=0.157). The carotid plaque CDKN2A mRNA levels were higher in the symptomatic patients than in the asymptomatic patients(p=0.050); this finding was also associated with the severity of internal carotid artery(ICA) stenosis(p=0.034). The p16(INK4a) immune(＋) cell counts in the carotid plaques were higher in the symptomatic patients than in the asymptomatic patients (p=0.056), as was the cell proliferation index(p=0.001).
An increased CDKN2A gene expression in carotid plaques may increase the severity of ICA stenosis, thus raising the risk of atherosclerosis and contributing to the development of symptoms. In addition, the p16(INK4a) expression is associated with carotid atherosclerosis in various patient subgroups.
已知位于9号染色体p21区域的INK4b-ARF-INK4a基因座在动脉粥样硬化的发展中起重要作用。INK4/ARF转录本p16(INK4a)抑制细胞周期蛋白依赖性激酶CDK4/CDK6的活性并阻止细胞周期进程。CDK抑制剂还调节血管平滑肌细胞（VSMC）中的G1/S期进程，并可能调节动脉粥样硬化的早期阶段。因此，我们旨在研究INK4/ARF基因座基因CDKN2A和CDKN2BAS的表达，以检测颈动脉斑块和大隐静脉组织样本中p16(INK4a)蛋白表达及细胞增殖水平。
共研究了50例患有颈动脉粥样硬化（CA）的患者（33例有症状者和17例无症状者）。使用定量实时聚合酶链反应（qRT-PCR）测定CDKN2A和CDKN2BAS基因表达水平。所有组织切片还使用免疫组织化学（IHC）分析p16(INK4a)和增殖细胞核抗原（PCNA）蛋白表达。
颈动脉斑块中CDKN2A基因表达显著高于大隐静脉组织（p=0.009），而CDKN2BAS转录本未见此类差异（p=0.157）。有症状患者的颈动脉斑块CDKN2A mRNA水平高于无症状患者（p=0.050）；这一发现也与颈内动脉（ICA）狭窄的严重程度相关（p=0.034）。有症状患者颈动脉斑块中的p16(INK4a)免疫（＋）细胞计数高于无症状患者（p=0.056），细胞增殖指数也是如此（p=0.001）。
颈动脉斑块中CDKN2A基因表达增加可能会增加ICA狭窄的严重程度，从而提高动脉粥样硬化风险并促使症状出现。此外，p16(INK4a)表达与不同患者亚组的颈动脉粥样硬化相关。
