严重高甘油三酯血症患者中apoA5基因新变异的初步研究

A preliminary report of apoA5 gene novel receptor-binding domain mutation in a patient with severe hypertriglyceridemia

目的 通过在严重高TG血症患者中进行apoA5基因的再测序，以期发现新的基因变异及其潜在的作用机制。 方法 对42例已排除LPL基因和apoCⅡ基因变异的严重高TG血症患者进行apoA5基因的再测序，构建出apoA5 cDNA野生型和突变型表达载体，通过在HEK293细胞中瞬时表达，用Western blot 观察细胞内蛋白的表达情况,用35S标记的培养基进行免疫沉淀放射性自显影观察分泌蛋白的情况。 结果 发现1例携带有T184S和V153M两个杂合性突变的患者，其中T184S为首次发现。并对患者家庭进行了基因型与表型的分析。成功构建载体，野生型和突变型载脂蛋白（Apo）A5蛋白质在细胞内均有表达，并且都能够分泌入培养基。 结论 通过对严重高TG血症的患者进行apoA5基因的再测序发现了一个新的突变T184S，该突变具有潜在的破坏ApoA5蛋白功能的作用，但并非造成其分泌障碍，还需进一步研究蛋白质－蛋白质间的作用机制。

Objective To find novel variants and explore potential mechanism of triglyceride metabolism by resequencing apoA5 gene in patients with severe hypertriglyceridemia. Methods The apoA5 gene in the patients with severe hypertriglyceridemia were resequenced, who had been excluded with variants in LPL or apoCⅡ. With constructed apoA5 cDNA expression vectors, transiently expression was observed in vitro and the protein expression was detected by Western blot and 35S-labeled immunoprecipitation. ResultsThe mutations of T184S and V153M were found in a patient with heterozygous variants in apoA5, and T184S was not reported before. Both mutant and wild type apoA5 cDNA expression vectors were constructed successfully. Western blot and immunoprecipitation showed they can be expressed in the cell and the mutational apoA5 can be secreted from the cell as well as wild type. Conclusion A novel mutation in apoA5 was found in a patient with severe hypertriglyceridemia, which has the potential damaging effect for the function of this protein but not the secretion function. It need further study on the interaction of apoA5 and other related proteins.