Division of Pediatric Gastroenterology and Hepatology, Department of Pediatrics, Shuang Ho Hospital, Taipei Medical University, No. 291, Jhong Jheng Road, Jhong Ho, New Taipei City, 23561, Taiwan.
Department of Pediatrics, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan.
J Biomed Sci. 2022 Dec 1;29(1):102. doi: 10.1186/s12929-022-00885-0.
yqiC is required for colonizing the Salmonella enterica serovar Typhimurium (S. Typhimurium) in human cells; however, how yqiC regulates nontyphoidal Salmonella (NTS) genes to influence bacteria-host interactions remains unclear.
The global transcriptomes of S. Typhimurium yqiC-deleted mutant (ΔyqiC) and its wild-type strain SL1344 after 2 h of in vitro infection with Caco-2 cells were obtained through RNA sequencing to conduct comparisons and identify major yqiC-regulated genes, particularly those involved in Salmonella pathogenicity islands (SPIs), ubiquinone and menaquinone biosynthesis, electron transportation chains (ETCs), and carbohydrate/energy metabolism. A Seahorse XFp Analyzer and assays of NADH/NAD and HO were used to compare oxygen consumption and extracellular acidification, glycolysis parameters, adenosine triphosphate (ATP) generation, NADH/NAD ratios, and HO production between ΔyqiC and SL1344.
After S. Typhimurium interacts with Caco-2 cells, yqiC represses gene upregulation in aspartate carbamoyl transferase, type 1 fimbriae, and iron-sulfur assembly, and it is required for expressing ilvB operon, flagellin, tdcABCD, and dmsAB. Furthermore, yqiC is required for expressing mainly SPI-1 genes and specific SPI-4, SPI-5, and SPI-6 genes; however, it diversely regulates SPI-2 and SPI-3 gene expression. yqiC significantly contributes to menD expression in menaquinone biosynthesis. A Kyoto Encyclopedia of Genes and Genomes analysis revealed the extensive association of yqiC with carbohydrate and energy metabolism. yqiC contributes to ATP generation, and the analyzer results demonstrate that yqiC is required for maintaining cellular respiration and metabolic potential under energy stress and for achieving glycolysis, glycolytic capacity, and glycolytic reserve. yqiC is also required for expressing ndh, cydA, nuoE, and sdhB but suppresses cyoC upregulation in the ETC of aerobically and anaerobically grown S. Typhimurium; priming with Caco-2 cells caused a reversed regulation of yiqC toward upregulation in these ETC complex genes. Furthermore, yqiC is required for maintaining NADH/NAD redox status and HO production.
Specific unreported genes that were considerably regulated by the colonization-associated gene yqiC in NTS were identified, and the key role and tentative mechanisms of yqiC in the extensive modulation of virulence factors, SPIs, ubiquinone and menaquinone biosynthesis, ETCs, glycolysis, and oxidative stress were discovered.
yqiC 是鼠伤寒沙门氏菌（S. Typhimurium）在人细胞中定殖所必需的；然而，yqiC 如何调节非伤寒沙门氏菌（NTS）基因以影响细菌-宿主相互作用尚不清楚。
通过 RNA 测序获得了体外感染 Caco-2 细胞 2 小时后 S. Typhimurium yqiC 缺失突变体（ΔyqiC）及其野生型菌株 SL1344 的全转录组，以进行比较并鉴定主要的 yqiC 调控基因，特别是那些参与沙门氏菌致病岛（SPI）、泛醌和甲萘醌生物合成、电子传递链（ETC）和碳水化合物/能量代谢的基因。使用 Seahorse XFp 分析仪和 NADH/NAD 和 HO 测定法比较 ΔyqiC 和 SL1344 之间的耗氧量和细胞外酸化、糖酵解参数、三磷酸腺苷（ATP）生成、NADH/NAD 比和 HO 生成。
鼠伤寒沙门氏菌与 Caco-2 细胞相互作用后，yqiC 抑制天冬氨酸氨甲酰转移酶、1 型菌毛和铁硫组装的基因上调，并且需要表达 ilvB 操纵子、鞭毛、tdcABCD 和 dmsAB。此外，yqiC 还需要表达主要的 SPI-1 基因和特定的 SPI-4、SPI-5 和 SPI-6 基因；然而，它对 SPI-2 和 SPI-3 基因表达的调节则各不相同。yqiC 对menaquinone 生物合成中的 menD 表达有重要贡献。京都基因与基因组百科全书分析显示，yqiC 与碳水化合物和能量代谢广泛相关。yqiC 有助于 ATP 的生成，分析仪的结果表明，yqiC 在能量应激下维持细胞呼吸和代谢潜力以及实现糖酵解、糖酵解能力和糖酵解储备是必需的。yqiC 还需要表达 ndh、cydA、nuoE 和 sdhB，但在有氧和无氧生长的鼠伤寒沙门氏菌的 ETC 中抑制 cyoC 的上调；用 Caco-2 细胞启动会导致 ETC 复合基因中 yiqC 对 yqiC 的调控发生逆转。此外，yqiC 还需要维持 NADH/NAD 氧化还原状态和 HO 生成。
鉴定出了非伤寒沙门氏菌中由定植相关基因 yqiC 显著调控的特定未报道基因，并发现了 yqiC 在广泛调节毒力因子、SPI、泛醌和甲萘醌生物合成、ETC、糖酵解和氧化应激方面的关键作用和推测机制。
