胰腺十二指肠同源异型盒-1、神经源性分化因子-1及肌腱膜纤维肉瘤癌基因同系物A三基因修饰小鼠诱导多潜能干细胞分化为胰岛素分泌细胞的研究

摘要

目的 观察胰岛素转录关键调控因子胰腺十二指肠同源异型盒-1(PDX-1)、神经源性分化因子-1(NeuroD1)及肌腱膜纤维肉瘤癌基因同系物A(MafA)对小鼠诱导多潜能干细胞(iPS)分化为胰岛素分泌细胞的作用.方法 重组腺病毒Ad-mPDX-1-IRES-绿色荧光蛋白(GFP)、Ad-mNeuroD1IRES-GFP、Ad-mMafA-IRES-GFP联合转染小鼠iPS细胞,体外培养后逆转录-聚合酶链反应(RT-PCR)检测胰岛β细胞功能基因表达;免疫荧光检测胰岛素蛋白表达及定位;酶联免疫吸附试验(ELISA)检测不同糖浓度下胰岛素的分泌量.将胰岛素分泌细胞移植到糖尿病小鼠肝脏,免疫组织化学检测其在体内胰岛素的表达,葡萄糖耐量试验及空腹血糖监测评估移植细胞在糖尿病小鼠体内的功能发挥.结果 三基因转染的小鼠iPS细胞能分化为胰岛素分泌细胞,RT-PCR结果显示其胰岛β细胞功能基因的表达与小鼠胰岛β细胞株MIN6相似;免疫荧光检测见细胞内有胰岛素合成;ELISA检测结果显示细胞对不同浓度葡萄糖有较好的反应性.当葡萄糖浓度为30 mmol/L,胰岛素释放量最高为(0.309 3±0.017 9) ng.免疫组织化学染色显示移植细胞注射区域的肝实质内可见相对集中的棕黄色染色,表明移植细胞有胰岛素分泌.糖耐量试验及空腹血糖监测显示移植细胞能够控制糖尿病小鼠的血糖水平,在体内发挥良好的治疗作用.结论 胰岛素转录关键调控因子PDX-1、NeuroD1和MafA三基因能使小鼠iPS细胞分化为具有显著胰岛素合成和分泌能力的胰岛素分泌细胞,在体内发挥一定的治疗作用.%Objective To evaluate the effect of insulin gene transcription regulators pancreatic and duodenal homeobox-1 (PDX-1),neurogenic differentiation-1 (NeuroD1) and V-maf musculoaponeurotic fibrosarcoma oncogene homologue A (MafA) on the differentiation of induced pluripotent stem cells (iPS)into insulin-producing cells.Methods iPS were infected with adenovirus (Ad-mPDX-1-IRES-GFP、AdmNeuroD1-IRES-GFP and Ad-mMafA-IRES-GFP),and then differentiated into insulin-producing cells in vitro.Reverse transcriptase-polymerase chain reaction (RT-PCR) was applied to detecting target genes and insulin gene expression,immunofluorescence for identifying the presence and location of insulin protein and mouse insulin enzyme-linked immunosorbent assay (ELISA) to evaluating the secretory volume of insulin at different concentration of glucose.Diabetic mice were transplanted with infection iPS under the liver parenchyma.The grafts were analyzed by immunohistochemistry for the presence of insulin-producing cells.Intraperitoneal glucose tolerance test and fasting plasma glucose were used to assess the functions exertion of engrafted cell in vivo and revealed the therapeutic effect.Results RT-PCR results showed that polygenemodified iPS and pancreatic β-cell line MIN6 have similar gene expression.Mouse insulin ELISA showed polygene-modified iPS have a Satisfactory response to different concentrations of glucose.When glucose concentration was 30 mmol/L,insulin release up to (0.309 3 ±0.017 9) rg.Immunohistochemistry was performed to detect the expression of insulin in the liver tissue of diabetic mice and it exhibited positive staining of insulin.The results of intraperitoneal glucose tolerance test and fasting plasma glucose demonstrated the ability of these insulin-producing cells-transplanted mice to dispose of a glucose load.Conclusion The combination of PDX-1,NeuroD1 and MafA markedly induces insulin biosynthesis and secretion in iPS.