Université de Bordeaux, INSERM-Institut National de la Santé et de la Recherche Médicale, BaRITOn-Bordeaux Research in Translational Oncology, UMR1053, 33076 Bordeaux, France.
Université de Bordeaux, TBMCore, CRISP'edit, TBMcore CNRS-Centre National de la Recherche Scientifique UMS3427/INSERM-Institut National de la Santé et de la Recherche Médicale US005, 33076 Bordeaux, France.
Toxins (Basel). 2020 Mar 12;12(3):174. doi: 10.3390/toxins12030174.
Enterohepatic Helicobacters, such as and are associated with several intestinal and hepatic diseases. Their main virulence factor is the cytolethal distending toxin (CDT). In the present study, whole genome microarray-based identification of differentially expressed genes was performed in vitro in HT-29 intestinal cells while following the ectopic expression of the active CdtB subunit of CDT. A CdtB-dependent upregulation of the V-maf musculoaponeurotic fibrosarcoma oncogene homolog B () gene encoding the MAFB oncoprotein was found, as well as the CdtB-dependent regulation of several MAFB target genes. The transduction and coculture experiments confirmed mRNA and protein induction in response to CDT and its CdtB subunit in intestinal and hepatic cell lines. An analysis of MAFB protein subcellular localization revealed a strong nuclear and perinuclear localization in the CdtB-distended nuclei in intestinal and hepatic cells. MAFB was also detected at the cell periphery of the CdtB-induced lamellipodia in some cells. The silencing of MAFB changed the cellular response to CDT with the formation of narrower lamellipodia, a reduction of the increase in nucleus size, and the formation of less γH2AX foci, the biomarker for DNA double-strand breaks. Taken together, these data show that the CDT of enterohepatic Helicobacters modulates the expression of the MAFB oncoprotein, which is translocated in the nucleus and is associated with the remodeling of the nuclei and actin cytoskeleton.
肠肝型幽门螺杆菌，如 和 ，与多种肠道和肝脏疾病有关。其主要毒力因子是细胞致死扩张毒素（CDT）。本研究采用基于全基因组微阵列的方法，在体外培养 HT-29 肠细胞时，异位表达 CDT 的活性 CdtB 亚基，检测差异表达基因。发现 CdtB 依赖性上调编码 MAFB 癌蛋白的 V-maf 肌肉腱膜纤维肉瘤癌基因同源物 B（）基因，以及 CdtB 依赖性调节几个 MAFB 靶基因。转导和共培养实验证实了肠道和肝脏细胞系中 CDT 及其 CdtB 亚基对 mRNA 和蛋白的诱导作用。MAFB 蛋白亚细胞定位分析显示，在 CdtB 扩张的细胞核中，MAFB 蛋白呈强核和核周定位，在一些细胞中，在 CdtB 诱导的片状伪足的细胞边缘也检测到 MAFB。MAFB 的沉默改变了细胞对 CDT 的反应，形成了更窄的片状伪足，细胞核增大的增加减少，γH2AX 焦点（DNA 双链断裂的生物标志物）形成减少。综上所述，这些数据表明肠肝型幽门螺杆菌的 CDT 调节 MAFB 癌蛋白的表达，该蛋白易位到细胞核，并与核和肌动蛋白细胞骨架的重塑有关。
