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Abstract：
Clostridioides difficile (C. difficile) is responsible for a spectrum of nosocomial/antibiotic-associated gastrointestinal diseases that are increasing in global incidence and mortality rates. The C. difficile pathogenesis is due to toxin A and B (TcdA/TcdB), both causing cytopathic and cytotoxic effects and inflammation. Recently, we demonstrated that TcdB induces cytopathic and cytotoxic (apoptosis and necrosis) effects in enteric glial cells (EGCs) in a dose/time-dependent manner and described the underlying signaling. Despite the role played by lipids in host processes activated by pathogens, to counter infection and/or induce cell death, to date no studies have investigated lipid changes induced by TcdB/TcdA. Here, we evaluated the modification of lipid composition in our in vitro model of TcdB infection. Apoptosis, cell cycle, cell viability, and lipidomic profiles were evaluated in EGCs treated for 24 h with two concentrations of TcdB (0.1 ng/mL; 10 ng/mL). In EGCs treated with the highest concentration of TcdB, not only an increased content of total lipids was observed, but also lipidome changes, allowing the separation of TcdB-treated cells and controls into different clusters. The statistical analyses also allowed us to ascertain which lipid classes and lipid molecular species determine the clusterization. Changes in lipid species containing inositol as polar head and plasmalogen phosphatidylethanolamine emerged as key indicators of altered lipid metabolism in TcdB-treated EGCs. These results not only provide a picture of the phospholipid profile changes but also give information regarding the lipid metabolism pathways altered by TcdB, and this might represent an important step for developing strategies against C. difficile infection.
摘要：
艰难梭菌(C.difficile）负责一系列医院/抗生素相关的胃肠道疾病，这些疾病的全球发病率和死亡率都在增加。艰难梭菌的发病机制是由于毒素A和B（TcdA/TcdB），引起细胞病变和细胞毒性作用和炎症。最近,我们证明了TcdB以剂量/时间依赖性方式诱导肠神经胶质细胞（EGC）的细胞病变和细胞毒性（凋亡和坏死）效应，并描述了潜在的信号传导。尽管脂质在病原体激活的宿主过程中发挥了作用，对抗感染和/或诱导细胞死亡，迄今为止，尚无研究调查TcdB/TcdA诱导的脂质变化。这里,我们在TcdB感染的体外模型中评估了脂质组成的修饰。细胞凋亡,细胞周期,细胞活力，在用两种浓度的TcdB（0.1ng/mL;10ng/mL）处理24小时的EGCs中评估脂质组学谱。在用最高浓度的TcdB处理的EGCs中，不仅观察到总脂质含量增加，但也有脂肪改变，允许将TcdB处理的细胞和对照分离成不同的簇。统计分析还使我们能够确定哪些脂质类别和脂质分子种类决定了聚类。在TcdB处理的EGC中，含有作为极性头的肌醇和磷脂酰乙醇胺的脂质种类的变化是脂质代谢改变的关键指标。这些结果不仅提供了磷脂谱变化的图片，而且还提供了有关TcdB改变的脂质代谢途径的信息，这可能是制定针对艰难梭菌感染的策略的重要一步。
