在高α脂蛋白血症患者中，对 CETP 启动子和 LIPC 基因中的新型变异进行功能特征分析。
Functional characterization of novel variants in the CETP promoter and the LIPC gene in subjects with hyperalphalipoproteinemia.
机构信息
Hormonal and Metabolic Disorders Research Unit, Department of Medicine, Faculty of Medicine, Chulalongkorn University, and King Chulalongkorn Memorial Hospital, Thai Red Cross Society, Patumwan, Bangkok 10330, Thailand.
出版信息
Clin Chim Acta. 2013 Feb 1;416:92-5. doi: 10.1016/j.cca.2012.11.024. Epub 2012 Dec 5.
BACKGROUND
Variants in the CETP and the LIPC genes, encoding cholesteryl ester transfer protein and hepatic lipase, respectively, are associated with high levels of HDL-cholesterol or hyperalphalipoproteinemia (HALP). Recently, we have identified three novel variants in the CETP promoter and two novel variants in LIPC in Thai subjects with HALP. In this study, we investigated the functions of these 5 variants in vitro.
METHODS
For CETP promoter variants, we used site-directed mutagenesis, transient expression in HepG2 cells and luciferase reporter assay. For LIPC variants, cDNA was cloned and mutagenesis for missense variants was performed before expression in HepG2 cells.
RESULTS
The transcriptional activities of -49G>T,-70C>T, and -372C>T CETP promoter variants were markedly reduced (5%, 8% and 30%, respectively, compared to that of the wild-type, P<0.001). For LIPC variants, hepatic lipase activities in the lysates of cells transfected with c.421A>G (p.G141S) and c.517G>A (p.V173M) variants were 41% and 46%, respectively, compared to that of the wild-type (P<0.05).
CONCLUSIONS
The recently-identified variants in the CETP promoter and in the LIPC gene may contribute to HALP. Our result may have a diagnostic application in the genetic evaluation of subjects with high HDL-cholesterol levels.
背景
载脂蛋白 CETP 基因和肝脂酶基因 LIPC 分别编码胆固醇酯转移蛋白和肝脂酶，其变体与高密度脂蛋白胆固醇（HDL-C）水平升高或高α脂蛋白血症（HALP）相关。最近，我们在泰国 HALP 患者中发现了 CETP 启动子中的 3 个新变体和 LIPC 中的 2 个新变体。在这项研究中，我们研究了这些 5 个变体在体外的功能。
方法
对于 CETP 启动子变体，我们使用定点诱变、瞬时转染 HepG2 细胞和荧光素酶报告基因检测。对于 LIPC 变体，我们在 HepG2 细胞中转录表达之前，对 cDNA 进行克隆并对错义变体进行诱变。
结果
-49G>T、-70C>T 和 -372C>T 的 CETP 启动子变体的转录活性明显降低（分别比野生型降低 5%、8%和 30%，P<0.001）。对于 LIPC 变体，转染 c.421A>G（p.G141S）和 c.517G>A（p.V173M）变体的细胞裂解物中的肝脂酶活性分别比野生型降低 41%和 46%（P<0.05）。
结论
最近在 CETP 启动子和 LIPC 基因中发现的变体可能导致 HALP。我们的结果可能在具有高 HDL-C 水平的受试者的遗传评估中具有诊断应用。
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