慢病毒介导shRNA沉默Nicastrin基因的人永生化角质形成细胞模型构建

Construction of a Nicastrin gene-silenced human immortalized keratinocyte cell model by lentivirus. mediated short hairpin RNA

目的 构建Nicastrin（NCT）基因的RNA干扰慢病毒表达载体，并在人永生化角质形成细胞（HaCaT细胞）上鉴定其沉默效率，构建NCT基因稳定下调的人永生化角质形成细胞模型，为后续研究NCT基因下调对角质形成细胞的生物学行为影响奠定实验基础。方法 设计3个靶向NCT基因特异性短发卡RNA（shRNA）表达序列并连接到慢病毒表达质粒pGLV3/H1/GFP ＋ Puro中，成功构建慢病毒重组表达质粒，并通过测序鉴定。将构建的重组表达质粒与包装质粒共转染293T细胞，产生慢病毒颗粒，并测其滴度。将HaCaT细胞分为空白组（未感染病毒）、阴性对照组（NC组，感染空载病毒LV3-shNC）和干扰组（感染NCT-shRNA1、2、3慢病毒）。流式细胞仪检测慢病毒转染效率，实时荧光定量PCR（qRT-PCR）、Western印迹检测靶基因的沉默效率，筛选出沉默效果最佳的干扰序列。结果 测序表明，NCT-shRNA慢病毒重组表达质粒构建成功。重组表达质粒与包装质粒共转染293T细胞后产生的慢病毒颗粒滴度为109 TU/ml。慢病毒感染HaCaT细胞后，流式细胞仪检测，慢病毒转染效率大于95%。qRT-PCR结果，与NC组相比，干扰组NCT mRNA表达量明显下降，其中NCT-shRNA1组NCT基因沉默效果最佳，干扰效率达到75%。Western印迹结果，与NC组相比，shRNA1组NCT蛋白表达抑制率为71.7%。结论 成功筛选出高效NCT-shRNA干扰序列，构建NCT-shRNA慢病毒重组表达载体，并构建NCT基因稳定下调的人永生化角质形成细胞模型。

Objective To construct a lentiviral vector delivering the Nicastrin （NCT） gene-targeted short hairpin RNA （shRNA） and determine gene-silencing efficiency of the vector in the human immortalized keratinocyte cell line HaCaT, and to construct a NCT gene-silenced HaCaT cell model to lay an experimental foundation for subsequently studying effects of NCT gene silencing on biological behavior of keratinocytes. Methods Three NCT gene-targeted shRNAs were designed and inserted into the pGLV3/H1/GFP ＋ Puro vector to construct three recombinant plasmids, which were then confirmed by sequencing. Recombinant plasmids combined with lentivirus packaging plasmids were co-transfected into 293T cells to obtain lentivirus particles, and the virus titer was determined. Cultured HaCaT cells were divided into 3 groups： blank group receiving no treatment, negative control group infected with the empty vector LV3-shNC, interference groups infected with lentivirus NCT-shRNA1, -shRNA2, -shRNA3, respectively. Flow cytometry was performed to determine transfection efficiency, and real-time fluorescence-based quantitative PCR （qRT-PCR） and Western blot analysis were conducted to determine efficiency of target gene silencing in HaCaT cells, so as to select the most efficient interference sequence. Results Sequencing analysis indicated that recombinant lentiviral vector NCT-shRNA was constructed successfully. After co-transfection of recombinant plasmids and lentivirus packaging plasmids into 293T cells, the titer of recombinant lentivirus particles was about 109 TU/ml. Flow cytometry showed that the transfection efficiency was greater than 95%. qRT-PCR revealed that the NCT mRNA was obviously down-regulated in the interference group compared with the negative control group, and NCT-shRNA1 was the most efficient sequence with interference efficiency being 75%. Western blot analysis showed that the inhibition rate of NCT protein was 71.7% in the shRNA1 group compared with the negative control group. Conclusion The most efficient NCT-shRNA interference sequence is screened out, and the recombinant lentiviral vector NCT-shRNA and an NCT gene-silenced HaCaT cell model are both constructed successfully.