Data_Sheet_1_The DNA adenine methylase of Salmonella Enteritidis promotes their intracellular replication by inhibiting arachidonic acid metabolism pathway in macrophages.docx

Macrophages can participate in immune responses by altering their metabolism, and play important roles in controlling bacterial infections. However, Salmonella Enteritidis can survive and proliferate in macrophages. After the deletion of DNA adenine methylase (Dam), the proliferation of Salmonella Enteritidis in macrophages decreased, the molecular mechanism is still unclear. After infecting macrophages with Salmonella Enteritidis wild type and dam gene deletion strains, intracellular metabolites were extracted and detected by non-targeted metabolomics and fatty acid targeted metabolomics. We found Dam had significant effects on arachidonic acid and related metabolic pathways in macrophages. The dam gene can promote the proliferation of Salmonella Enteritidis in macrophages by inhibiting the metabolic pathway of cytosolic phospholipase A2-mediated arachidonic acid production and conversion to prostaglandin E2 in macrophages, reducing the secretion of the pro-inflammatory factors IL-1β and IL-6. In addition, inhibition of arachidonic acid-related pathways in macrophages by Arachidonyl trifluoromethyl ketone could restore the proliferation of dam gene deletion strains in macrophages. This study explored the role of Dam in the process of Salmonella Enteritidis invading host cells from the perspective of host cell metabolism, and provides new insights into the immune escape mechanism of Salmonella Enteritidis.

巨噬细胞能够通过调节其代谢参与免疫反应，并在控制细菌感染中发挥着至关重要的作用。然而，沙门氏菌肠炎亚型能够在巨噬细胞中存活并增殖。在DNA腺嘌呤甲基化酶（Dam）基因被删除后，沙门氏菌肠炎亚型在巨噬细胞中的增殖得到了抑制，但其分子机制尚不明确。通过感染野生型沙门氏菌肠炎亚型和dam基因删除菌株的巨噬细胞，我们提取并检测了细胞内的代谢物，采用非靶向代谢组学和脂肪酸靶向代谢组学方法。研究发现，Dam对巨噬细胞中的花生四烯酸及其相关代谢途径具有显著影响。Dam基因通过抑制巨噬细胞中由细胞质磷脂酶A2介导的花生四烯酸的产生及其转化为前列腺素E2的代谢途径，从而促进沙门氏菌肠炎亚型在巨噬细胞中的增殖，并减少促炎因子IL-1β和IL-6的分泌。此外，通过抑制巨噬细胞中花生四烯酸相关途径的Arachidonyl trifluoromethyl ketone，可以恢复dam基因删除菌株在巨噬细胞中的增殖。本研究从宿主细胞代谢的角度探讨了Dam在沙门氏菌肠炎亚型侵入宿主细胞过程中的作用，并为沙门氏菌肠炎亚型的免疫逃逸机制提供了新的见解。