Kontizas Eleftherios, Tastsoglou Spyros, Karamitros Timokratis, Karayiannis Yiannis, Kollia Panagoula, Hatzigeorgiou Artemis G, Sgouras Dionyssios N
Laboratory of Medical Microbiology, Hellenic Pasteur Institute, 11521 Athens, Greece.
Department of Genetics and Biotechnology, Faculty of Biology, National and Kapodistrian University of Athens, 15772 Athens, Greece.
Microorganisms. 2020 Dec 16;8(12):2007. doi: 10.3390/microorganisms8122007.
infection induces a plethora of DNA damages. Gastric epithelial cells, in order to maintain genomic integrity, require an integrous DNA damage repair (DDR) machinery, which, however, is reported to be modulated by the infection. CagA is a major virulence factor, associated with increased risk for gastric carcinogenesis. Its pathogenic activity is partly regulated by phosphorylation on EPIYA motifs. Our aim was to identify effects of infection and CagA on DDR, investigating the transcriptome of AGS cells, infected with wild-type, ΔCagA and EPIYA-phosphorylation-defective strains. Upon RNA-Seq-based transcriptomic analysis, we observed that a notable number of DDR genes were found deregulated during the infection, potentially resulting to base excision repair and mismatch repair compromise and an intricate deregulation of nucleotide excision repair, homologous recombination and non-homologous end-joining. Transcriptome observations were further investigated on the protein expression level, utilizing infections of AGS and GES-1 cells. We observed that CagA contributed to the downregulation of Nth Like DNA Glycosylase 1 (NTHL1), MutY DNA Glycosylase (MUTYH), Flap Structure-Specific Endonuclease 1 (FEN1), RAD51 Recombinase, DNA Polymerase Delta Catalytic Subunit (POLD1), and DNA Ligase 1 (LIG1) and, contrary to transcriptome results, Apurinic/Apyrimidinic Endodeoxyribonuclease 1 (APE1) upregulation. Our study accentuates the role of CagA as a significant contributor of infection-mediated DDR modulation, potentially disrupting the balance between DNA damage and repair, thus favoring genomic instability and carcinogenesis.
感染会引发大量DNA损伤。胃上皮细胞为维持基因组完整性，需要完整的DNA损伤修复（DDR）机制，然而据报道该机制会受到感染的调节。细胞毒素相关基因A（CagA）是一种主要的毒力因子，与胃癌发生风险增加有关。其致病活性部分受EPIYA基序磷酸化的调节。我们的目的是确定感染和CagA对DDR的影响，研究感染野生型、ΔCagA和EPIYA磷酸化缺陷菌株的AGS细胞的转录组。基于RNA测序的转录组分析显示，我们观察到大量DDR基因在感染期间失调，这可能导致碱基切除修复和错配修复受损，以及核苷酸切除修复、同源重组和非同源末端连接的复杂失调。利用AGS和GES - 1细胞感染，在蛋白质表达水平上进一步研究转录组观察结果。我们观察到CagA导致Nth样DNA糖基化酶1（NTHL1）、MutY DNA糖基化酶（MUTYH）、瓣状结构特异性内切核酸酶1（FEN1）、RAD51重组酶、DNA聚合酶δ催化亚基（POLD1）和DNA连接酶1（LIG1）下调，并且与转录组结果相反，脱嘌呤/脱嘧啶内切脱氧核糖核酸酶1（APE1）上调。我们的研究强调了CagA作为感染介导的DDR调节的重要贡献者的作用，可能破坏DNA损伤与修复之间的平衡，从而促进基因组不稳定和致癌作用。
