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目的:构建早老蛋白增强子2（PSENEN）基因沉默的人永生化角质形成细胞（HaCaT）模型，探究PSENEN基因表达下调对HaCaT细胞增殖以及γ分泌酶表达的影响。方法:设计3组靶向PSENEN基因的shRNA序列，与线性化的LV3-pGLV-h1-GFP-puro载体构建慢病毒重组表达质粒，经酶切及测序鉴定后，进行慢病毒的包装、纯化和滴度测定。将HaCaT细胞分为5组进行转染：shRNA1组、shRNA2组、shRNA3组分别加入含沉默PSENEN基因的shRNA1、shRNA2、shRNA3慢病毒原液，NC组加入含阴性对照shNC慢病毒原液，空白组不加病毒液。转染完成后，荧光显微镜下观察荧光表达，流式细胞仪检测转染效率。CCK8法测定HaCaT细胞增殖活性，实时荧光定量PCR（qPCR）、Western印迹法分别检测PSENEN、呆蛋白（NCT）、早老蛋白1（PS1）、前咽缺陷蛋白1a（APH1a）mRNA、蛋白的相对表达量。统计分析采用重复测量方差分析、单因素方差分析，组间两两比较采用LSD-n t检验。n 结果:倒置荧光显微镜下观察到shRNA1~shRNA3组、NC组均有荧光表达，流式细胞仪示转染效率均达98%以上。qPCR、Western印迹法显示，与NC组（1.054 ± 0.272、1.076 ± 0.075）相比，shRNA1、shRNA2、shRNA3组PSENEN mRNA（0.187 ± 0.010、0.163 ± 0.022、0.174 ± 0.009）、蛋白（0.219 ± 0.097、0.208 ± 0.014、0.185 ± 0.062）表达均显著降低（均n P < 0.001）。CCK8法显示，与NC组相比，shRNA1组细胞增殖活性在0、12、36、48 h均显著增高（均 n P 0.05）；shRNA2、shRNA3组在0、12、24、36、48、60 h细胞增殖水平均显著高于NC组（均 n P 0.05），mNCT、imNCT、PS1-CTF、APH1a蛋白相对表达差异有统计学意义（ n F值分别为39.268、5.929、27.842、20.663，均n P ≤ 0.01）。与NC组相比，shRNA1、shRNA2、shRNA3组mNCT、PS1-CTF、APH1a蛋白表达均显著降低（均n P 0.05）。n 结论:成功构建了PSENEN基因沉默的HaCaT细胞模型，PSENEN基因沉默会引起HaCaT细胞增殖活性增强，γ分泌酶其他亚基蛋白含量下降。“,”Objective:To establish a presenilin enhancer-2 (PSENEN) gene-silenced human immortalized keratinocyte (HaCaT) cell model, and to evaluate the effect of PSENEN gene silencing on the proliferation of and γ-secretase expression in HaCaT cells.Methods:Three shRNAs targeting the PSENEN gene were constructed, and inserted into the linearized LV3-pGLV-h1-GFP-puro vector to establish a recombinant lentiviral expression plasmid. After restriction enzyme digestion and sequencing, lentiviral packaging and purification were performed, and lentiviral titer was determined. Cultured HaCaT cells were divided into 5 groups: shRNA1, shRNA2 and shRNA3 groups treated with the lentivirus solutions containing PSENEN gene-targeted shRNA1, shRNA2 and shRNA3 respectively, NC group treated with the lentivirus solution containing a negative control shRNA (shNC) , and blank group treated without lentivirus solution. After transfection, inverted fluorescence microscopy was performed, and transfection efficiency was determined by flow cytometry. Cell counting kit-8 (CCK8) assay was performed to evaluate the effect of PSENEN gene silencing on the proliferation of HaCaT cells, and real-time fluorescence-based quantitative PCR (qPCR) and Western blot analysis were conducted to determine the mRNA and protein expression of PSENEN, nicastrin (NCT) , presenilin-1 (PS1) and anterior pharynx defective 1a (APH1a) genes respectively. Statistical analysis was carried out by using repeated measures analysis of variance, one-way analysis of variance, and least significant difference n t test for multiple comparisons.n Results:Inverted fluorescence microscopy showed that fluorescence was observed in the shRNA1 group, shRNA2 group, shRNA3 group and NC group, and flow cytometry showed that the transfection efficiency was over 98% in the above 4 groups. qPCR and Western blot analysis revealed that the mRNA and protein expression of PSENEN gene significantly decreased in the shRNA1 (0.187 ± 0.010, 0.219 ± 0.097, respectively) , shRNA2 (0.163 ± 0.022, 0.208 ± 0.014, respectively) and shRNA3 (0.174 ± 0.009, 0.185 ± 0.062, respectively) groups compared with the NC group (1.054 ± 0.272, 1.076 ± 0.075, respectively, all n P < 0.001) . CCK8 assay showed that the cellular proliferative activity significantly increased in the shRNA1 group compared with the NC group at 0, 12, 36 and 48 hours (all n P 0.05) ; the cellular proliferative activity was significantly higher in the shRNA2 and shRNA3 groups than in the NC group at 0, 12, 24, 36, 48 and 60 hours (all n P 0.05) , while the relative protein expression level of mature NCT (mNCT) , immature NCT (imNCT) , carboxyl-terminal fragment of PS1 (PS1-CTF) and APH1a significantly differed among the above 5 groups ( n F= 39.268, 5.929, 27.842, 20.663, respectively, all n P ≤ 0.01) . Compared with the NC group, the shRNA1, shRNA2 and shRNA3 groups all showed significantly decreased protein expression of mNCT, PS1-CTF and APH1a (all n P 0.05) .n Conclusion:The PSENEN gene-silenced HaCaT cell model was successfully constructed, and the PSENEN gene silencing could lead to an increase in the cellular proliferative activity of HaCaT cells and a decrease in the protein expression of γ-secretase subunits mNCT, PS1-CTF and APH1a.