Xie Yuan, Zhou Jian Jiang, Zhao Yan, Zhang Ting, Mei Liu Zheng
Key Laboratory of Endemic and Ethnic Diseases, Guizhou Medical University, Ministry of Education, China; Key Laboratory of Medical Molecular Biology, Guizhou Medical University, Guizhou Province, China.
Key Laboratory of Endemic and Ethnic Diseases, Guizhou Medical University, Ministry of Education, China; Key Laboratory of Medical Molecular Biology, Guizhou Medical University, Guizhou Province, China; Affiliated Hospital, Guiyang Medical University, No. 9, Beijing Road, Guiyang 550004, China.
Microb Pathog. 2017 Jul;108:129-136. doi: 10.1016/j.micpath.2017.05.003. Epub 2017 May 3.
The aim of this study was to evaluate the correlation between H. pylori infection and global DNA methylation, as well as the methylation levels of the gastrin promoters.
We constructed a eukaryotic expression vector, pcDNA3.1::cagA, and transfected it into GES-1 gastric mucosal cells and SGC-7901 gastric cancer cells. Both cell lines were infected with the H. pylori/CagA strain NCTC11637. Then, we detected global DNA methylation by capture and detection antibodies, followed by colorimetric quantification. The methylation levels of the gastrin promoter were evaluated by base-specific cleavage and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry.
In H. pylori/CagA-infected GES-1 and SGC-7901 cells, the methylation levels of genomic DNA decreased by 49.4% and 18.8%, and in GES-1 and SGC-7901 cells transfected with pcDNA3.1::cagA, the methylation levels of genomic DNA decreased by 17.05% and 25.6%, respectively. Among 24 methylation sites detected in the gastrin promoter region, the methylation levels of 9 CpG sites were significantly decreased in H. pylori/CagA+-infected and pcDNA3.1:: cagA-transfected cells in comparison to corresponding control cells.
These results indicate that H. pylori/CagA decreases the methylation of the genome and the gastrin promoter at some CpG sites in gastric mucosal and gastric cancer cells.
本研究旨在评估幽门螺杆菌感染与全基因组DNA甲基化之间的相关性，以及胃泌素启动子的甲基化水平。
我们构建了真核表达载体pcDNA3.1::cagA，并将其转染至GES-1胃黏膜细胞和SGC-7901胃癌细胞中。两种细胞系均感染幽门螺杆菌/CagA菌株NCTC11637。然后，我们通过捕获和检测抗体检测全基因组DNA甲基化，随后进行比色定量。通过碱基特异性切割和基质辅助激光解吸电离飞行时间质谱法评估胃泌素启动子的甲基化水平。
在幽门螺杆菌/CagA感染的GES-1和SGC-7901细胞中，基因组DNA的甲基化水平分别降低了49.4%和18.8%，在转染了pcDNA3.1::cagA的GES-1和SGC-7901细胞中，基因组DNA的甲基化水平分别降低了17.05%和25.6%。在胃泌素启动子区域检测到的24个甲基化位点中，与相应对照细胞相比，幽门螺杆菌/CagA阳性感染和pcDNA3.1::cagA转染细胞中9个CpG位点的甲基化水平显著降低。
这些结果表明，幽门螺杆菌/CagA降低了胃黏膜和胃癌细胞中某些CpG位点的基因组和胃泌素启动子的甲基化。
