Enhanced Activity of Variant Phospholipase C-1 Protein (R257H) Detected in Patients With Coronary Artery Spasm
Enhanced Activity of Variant Phospholipase C-1 Protein (R257H) Detected in Patients With Coronary Artery Spasm
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DOI：
10.1161/01.cir.0000014613.36469.3f
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发表时间：
2002-04
期刊：
影响因子：
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通讯作者：
T. Nakano;T. Osanai;H. Tomita;M. Sekimata;Y. Homma;K. Okumura
中科院分区：
文献类型：
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作者：
T. Nakano;T. Osanai;H. Tomita;M. Sekimata;Y. Homma;K. Okumura
背景：我们最近证明，从冠状动脉痉挛性心绞痛（CSA）患者获得的培养皮肤成纤维细胞中磷脂酶C (PLC) -1活性增强。我们检验了PLC-1异构体结构异常是活性增强的原因的假设。方法与结果：对从成纤维细胞中获得的PLC-1基因编码的cDNA序列分析显示，在一例CSA患者的864位核苷酸上出现了一次鸟嘌呤向腺嘌呤(A)的转化，导致精氨酸257被组氨酸（R257H）取代。单链构象多态性分析显示，CSA患者基因组DNA中864A/A的发生率高于男性对照组（57例CSA患者中有6例，62例对照组中有1例，P <0.05）。在游离钙浓度为10−8 ~ 10−7 mol/L范围内，变异PLC-1蛋白的活性是野生型蛋白的2倍。转染变异体PLC-1的人胚胎肾293细胞的基线细胞内钙浓度（[Ca2+]i）高于野生型细胞。在乙酰胆碱浓度为10−6和10−5 mol/L时，变异PLC-1细胞的[Ca2+]i的峰值升高高于野生型细胞。结论：这些发现表明，在CSA患者中检测到的PLC-1基因R257H变异与酶活性增强有关，并描述了CSA患者冠状动脉血管运动增强的新机制。
Background—We recently demonstrated that phospholipase C (PLC)–1 activity in cultured skin fibroblasts obtained from patients with coronary spastic angina (CSA) is enhanced. We tested the hypothesis that structural abnormality in PLC-1 isoform is a cause of the enhanced activity. Methods and Results—Sequence analysis of the cDNA coding for PLC-1 obtained from fibroblasts revealed that one conversion of guanine to adenine (A) was present at nucleotide position 864 in one CSA patient, resulting in the amino acid replacement of arginine 257 by histidine (R257H). The incidence of 864A/A in genomic DNA, analyzed by single-strand conformation polymorphism, was greater in patients with CSA than in male control subjects (6 of 57 patients with CSA versus 1 of 62 control subjects, P <0.05). The activity of the variant PLC-1 protein under free calcium concentration between 10−8 and 10−7 mol/L was 2-fold higher than that of the wild-type protein. Baseline intracellular calcium concentration ([Ca2+]i) in human embryonic kidney 293 cells transfected with the variant PLC-1 was higher than that in cells with the wild type. The peak increase in [Ca2+]i in response to acetylcholine at 10−6 and 10−5 mol/L was greater in the cells with the variant PLC-1 than in those with the wild type. Conclusions—These findings indicate that the R257H variant in the PLC-1 gene detected in patients with CSA is associated with enhancement of enzyme activity, and they describe a novel mechanism for the enhanced coronary vasomotility in CSA.