A Potential Association between Helicobacter pylori CagA EPIYA and Multimerization Motifs with Cytokeratin 18 Cleavage Rate during Early Apoptosis
A Potential Association between Helicobacter pylori CagA EPIYA and Multimerization Motifs with Cytokeratin 18 Cleavage Rate during Early Apoptosis
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DOI：
10.1111/j.1523-5378.2012.00954.x
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发表时间：
2012-10-01
期刊：
影响因子：
4.4
通讯作者：
Mohammadi, Marjan
中科院分区：
文献类型：
--
作者：
Saberi, Samaneh;Douraghi, Masoumeh;Mohammadi, Marjan
背景和目标：幽门螺杆菌是一种高度多样化的病原体，在其终生感染过程中会遇到上皮细胞作为最初的防御屏障。上皮细胞的结构可以通过微丝的分裂而被破坏。细胞角蛋白18（CK 18）是一种中间丝，其裂解被认为是效应半胱天冬酶激活后细胞凋亡过程中的早期事件。方法：对76例消化不良患者进行幽门螺杆菌分离。PCR和Western blotting分别检测cagA 3可变区和CagA蛋白的表达。AGS细胞与不同浓度的H. pylori菌株，使用对CK 18裂解诱导的新表位特异性的M30单克隆抗体进行流式细胞术分析。结果：AGS细胞与H. pylori菌株携带更多数量的cagA EPIYA-C和多聚化（CM）基序。另一方面，H.相对于EPIYA-C，具有更多数量的EPIYA-B的pylori菌株表现出CK 18裂解率的降低。因此，H. pylori介导的CK 18裂解似乎与CagA EPIYA-C和CM基序的数目成比例，这似乎在EPIYA-B基序存在下被淡化。结论：我们的观察将cagA变异体的异质性与H. pylori菌株诱导CK 18裂解作为胃上皮细胞凋亡的早期指示支持了凋亡可能是类型特异性特征的事实。然而，需要额外的cagA靶向实验，以明确识别EPIYA和CM基序在细胞凋亡和/或负责任的效应分子中的作用。
Background and Aims: Helicobacter pylori is a highly diverse pathogen, which encounters epithelial cells as the initial defense barrier during its lifelong infection. The structure of epithelial cells can be disrupted through cleavage of microfilaments. Cytokeratin 18 (CK18) is an intermediate filament, the cleavage of which is considered an early event during apoptosis following activation of effector caspases. Methods: Helicobacter pylori strains were isolated from 76 dyspeptic patients. cagA 3 variable region and CagA protein status were analyzed by PCR and western blotting, respectively. Eight hours post-co-culture of AGS cells with different H. pylori strains, flow cytometric analysis was performed using M30 monoclonal antibody specific to CK18 cleavage-induced neo-epitope. Results: Higher rates of CK18 cleavage were detected during co-culture of AGS cells with H. pylori strains bearing greater numbers of cagA EPIYA-C and multimerization (CM) motifs. On the other hand, H. pylori strains with greater numbers of EPIYA-B relative to EPIYA-C demonstrated a decrease in CK18 cleavage rate. Thus, H. pylori-mediated cleavage of CK18 appeared proportional to the number of CagA EPIYA-C and CM motifs, which seemed to be downplayed in the presence of EPIYA-B motifs. Conclusions: Our observation associating the heterogeneity of cagA variants with the potential of H. pylori strains in the induction of CK18 cleavage as an early indication of apoptosis in gastric epithelial cells supports the fact that apoptosis may be a type-specific trait. However, additional cagA-targeted experiments are required to clearly identify the role of EPIYA and CM motifs in apoptosis and/or the responsible effector molecules.