To construct a cell line of oral mucosa epithelial cells that stably express human telomerase reverse transcriptase (hTERT) by lentiviral vectors, approaches for the establishment of stable and efficient immortalized oral mucosa epithelial cell lines were explored.Whole RNA was extracted from 293T cells. The hTERT gene was amplified by polymerase chain reaction (PCR) and cloned into the lentiviral vector as pLVX-puro-hTERT. The lentivirus particles were successfully packaged and used to infect primary oral epithelial cells. The positive cell clones were selected by puromycin. Finally, the expression of hTERT was examined by real-time fluorescent quantitative PCR (qRT-PCR) and Western blot analysis.The sequencing results confirmed the construction of the recombinant lentivirus pLVX-puro-hTERT. The morphology of infected cells was similar to that of normal oral mucosal epithelial cells, with a cobble stone-like appearance. The qRT-PCR and Western blot results showed that hTERT was overexpressed in infected cells compared with the normal group (P<0.05).The oral epithelial cell line with stable expression of hTERT was successfully established by the lentivirus, which provides an experimental basis for the establishment of a highly efficient and stable oral epithelial immortalized cell line.目的 通过慢病毒法建立稳定表达外源性人端粒酶逆转录酶（hTERT）基因的口腔黏膜上皮细胞（OMECs），探索构建高效、稳定的永生化OMECs细胞系的方法。方法 提取293T细胞总RNA，应用聚合酶链反应（PCR）法扩增hTERT基因全长，构建重组慢病毒载体pLVX-puro-hTERT。包装慢病毒颗粒后感染人正常OMECs，经嘌呤霉素抗性筛选获得阳性克隆，采用实时荧光定量PCR法和Western blot法检测hTERT基因mRNA和蛋白的表达水平。结果 成功构建了pLVX-puro-hTERT过表达慢病毒载体并感染到OMECs中；感染细胞与正常OMECs形态相似，呈铺路石样生长；实时荧光定量PCR和Western blot结果均显示，hTERT在感染细胞中高表达，与正常细胞相比差异有统计学意义（P<0.05）。结论 通过慢病毒法成功建立了过表达hTERT的OMECs稳定细胞系，为构建高效、稳定增殖的人永生化OMECs细胞系奠定了实验基础。.
This study aimed to evaluate the biological characteristics of a human specifically targeted antimi- crobial peptide C16LL-37 against Streptococcus mutans (S. mutans).In this study, an antimicrobial peptide LL-37, a peptide derived from CSP(C16) (S. mutans competence stimulating peptide), and recombinant peptide C16LL-37 were synthesized by Fmoc-chemistry-based strategy. The selectivity and antibacterial activity of C16LL-37 were identified by the colony counting method on microbial culture plates. After treatment of C16LL-37 at 32 µmol · L⁻¹, the morphological changes in S. mutans were observed by using scanning electron microscopy (SEM). In addition, enzyme-linked immunosorbent assay was used to evaluate the hemolytic activity and antibacterial activity of C16LL-37 under different conditions.1) The minimum inhibitory concentration of C16LL-37 was 16 µmol · L⁻¹, and the minimum bactericidal concentration was 64 μmol ·L⁻¹. 2) The survival rate of S. mutans was 3.46% after C16LL-37 treatment at 64 µmo-L⁻¹ for 30 min, whereas it was 0% at 64 µmol · L⁻¹ for 60 min. The survival rates of four other kinds of bacteria were more than 60% at any time (P < 0.05). 3) The morphological change in S. mutans was observed after C16LL-37 treatment at 32 µmol · L⁻¹ by using SEM. S. mutans presented an irregular shape, rough surface, and evident splitting. 4) The hemolysis rate of C16LL-37 (≤ 64 µmol · L⁻¹) was less than 0.33%. 5) This study showed no significant in- fluence on the antibacterial activity of C16LL-37 under different conditions, such as temperature, pH, salinity, and trypsin at low concentration (P > 0.05).C16LL-37 exhibited obvious specificity for S. mutans, strong antibacterial activity, low toxicity, and high stability. Thus, C16LL-37 has good potential in caries research and clinical application.
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