α1,3GT siRNA打靶杂合子猪肝细胞阴性表达半乳糖转移酶

目的 研究联合应用基因敲除及RNA干扰(siRNA)技术对猪α1，3半乳糖转移酶(α1，3GT)基因修饰后，阳性猪杂合子( ／-)肝细胞的GT基因是否获得有效沉默并影响人天然抗体介导的细胞毒性作用。方法用pPNTloxPneo和PMXSV／U6载体构建猪GT基因敲除并siRNA载体，转染中国实验用小型猪的肝细胞，筛选获取杂合子克隆( ／-)。Northern blot检测GT mRNA表达，四甲基偶氮唑盐方法评估天然抗体细胞毒性。结果 野生型和pPNTloxPGT转染的杂合子猪肝细胞的inRNA表达阳性，而pPNTloxPGTsiRNA载体转染的杂合猪肝细胞阴性表达α1，3GT mRNA;pPNTloxPGT转染细胞( ／-)和野生型( ／ )猪肝细胞对人天然抗体介导的细胞毒性实验敏感，而pPNTloxPGTsiRNA转染细胞( ／-)则对毒性试验敏感性明显下降，只检测到17％细胞毒性。结论 对猪GT联合应用基因敲除及SiRNA能够在阳性猪杂合子肝细胞内有效沉默GT基因，降低猪肝细胞对人天然抗体细胞毒的敏感性。

The porcine α1,3 galactosyltransferase gene siRNA targeted heterozygous hepatocyte negative express GT

OBJECTIVE: To study whether the porcine alpha1, 3 galactosyltransferase gene siRNA targeted heterozygous hepatocyte negatively expresses GT mRNA and resists to the cytotoxicity of nature antibody in human serum. METHODS: The porcine alpha1, 3 galactosyltransferase gene siRNA targeted vector (pPNTloxPGTsiRNA) were construct with pPNTloxPGT and pMXSV/U6 vector. Positive-negative selection was used to produce a heterozygous pPNTloxPGTsiRNA knockout (+/-) clone. The GT mRNA expressions were detected with northern blot. Complement-mediated NAb cytotoxicity after incubation of hepatocytes with NAbs and complement was determined using 3- (4, 5-dimethylthiazol-2-yl)-5-(3-carboxymethyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium(MTS, tetrazolium salt) colorimetric assay. RESULTS: The pPNTloxPGTsiRNA targeted porcine hepatocyte (+/-) negative express GT mRNA. Only 14% to 18% cytotoxicity can be detected at the highest serum concentration. The pPNTloxPGT targeted porcine hepatocyte (+/-) express GT mRNA just as the wild type porcine cells and the cytotoxicity are 77% to 83%. CONCLUSION: The porcine a1, 3 galactosyltransferase gene siRNA targeted heterozygous hepatocyte (+/-) negative express GT and resisted to nature antibody in human serum.