MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, 210095, China.
Braz J Microbiol. 2022 Mar;53(1):289-301. doi: 10.1007/s42770-021-00627-8. Epub 2021 Oct 15.
Vibrio parahaemolyticus is an important foodborne pathogenic bacterium that harbors the type III secretion system 1 (T3SS1) as an essential virulence factor. However, the pathogenesis and infection mechanism mediated by T3SS1 are not entirely clarified. Similar to previous studies on other T3SS-positive bacteria, the T3SS1 needle is a major extracellular component in V. parahaemolyticus. We recently showed that the needle gene-deletion mutant (ΔvscF) exhibited markedly decreased cytotoxicity and effector translocation during interaction with HeLa cells. To further elucidate the pathogenesis of T3SS1 during host cell infection, bacterial RNA was extracted from wild-type POR-1 and ΔvscF mutants under infected condition for comparative RNA sequencing analysis in HeLa cell. The results showed that 120 differentially expressed genes (DEGs) were identified in the ΔvscF-infected group. These encoded proteins of DEGs, such as VP2088, VP2089, and VP2091, were annotated as ABC transporter system, whereas VP0757, VP1123, and VP1289 may be new transcriptional regulators. In addition, the downregulation of T3SS1 had a positive influence on the expression of T3SS2. Moreover, the transcription of the basal body is unaffected by the needle, and there was a close relation among the tip, translocon, and needle, because bacterial adenylate cyclase two-hybrid system (BACTH system) assay indicated the interaction of VP1656, VP1670, VP1693, and VP1694 (VscF). This study provides insights into transcription mechanism of T3SS1 upon infecting HeLa cell, which is expected to better clarify the T3SS1 virulent mechanism.
副溶血性弧菌是一种重要的食源性致病菌,其携带的 III 型分泌系统 1(T3SS1)是一种重要的毒力因子。然而,T3SS1 介导的发病机制和感染机制尚未完全阐明。与之前对其他 T3SS 阳性细菌的研究类似,T3SS1 针是副溶血性弧菌的主要细胞外成分。我们最近表明,针基因缺失突变体(ΔvscF)在与 HeLa 细胞相互作用时,细胞毒性和效应物易位明显降低。为了进一步阐明宿主细胞感染过程中 T3SS1 的发病机制,从野生型 POR-1 和 ΔvscF 突变体中提取了感染条件下的细菌 RNA,用于 HeLa 细胞中比较 RNA 测序分析。结果表明,在ΔvscF 感染组中鉴定出 120 个差异表达基因(DEGs)。这些 DEGs 编码的蛋白,如 VP2088、VP2089 和 VP2091,被注释为 ABC 转运系统,而 VP0757、VP1123 和 VP1289 可能是新的转录调节因子。此外,T3SS1 的下调对 T3SS2 的表达有积极影响。此外,针不会影响基础体的转录,并且尖端、转位器和针之间存在密切关系,因为细菌腺苷酸环化酶双杂交系统(BACTH 系统)测定表明 VP1656、VP1670、VP1693 和 VP1694(VscF)之间的相互作用。本研究深入了解了 T3SS1 在感染 HeLa 细胞时的转录机制,有望更好地阐明 T3SS1 的毒力机制。