College of Veterinary Medicine, Yangzhou University, Yangzhou, Jiangsu 225009, China; Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, Jiangsu 225009, China.
College of Veterinary Medicine, Yangzhou University, Yangzhou, Jiangsu 225009, China; Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, Jiangsu 225009, China.
Int Immunopharmacol. 2020 Jun;83:106406. doi: 10.1016/j.intimp.2020.106406. Epub 2020 Mar 16.
Selenium can alleviate the inflammatory reaction infected by Staphylococcus aureus (S. aureus). However, the role of selenium on the autophagy in RAW264.7 macrophages infected by S. aureus has not been reported. The goal of this study was to clarify the effect of selenium on the autophagy and related inflammatory pathways (MAPK and NF-κB) in RAW264.7 macrophages infected by S. aureus. RAW264.7 macrophages were co-treated with NaSeO and S. aureus. The expression of related inflammatory pathways (MAPK and NF-κB) and autophagy-related proteins were detected by Western blotting. The microtubule-binding protein light chain 3 (LC3) puncta were measured with immunofluorescence staining. The ultrastructure of RAW264.7 macrophages infected by S. aureus was detected by transmission electron microscope (TEM). And plate counting method was used to detect the proliferation of S. aureus in RAW264.7 macrophages. The results showed that the expression levels of LC3 II increased and the expression levels of p62 decreased after adding selenium, compared with S. aureus infection group. Compared with S. aureus infection group, the intracellular LC3 puncta and autophagic vesicles, autophagosomes, and autolysosomes increased with selenium supplementation. The number of S. aureus proliferation decreased with addition of selenium, compared with S. aureus infection group. Selenium could significantly inhibit the phosphorylation of MAPK and NF-κB signaling pathway key proteins, compared with S. aureus infection group. In summary, selenium could promote the autophagy in macrophages infected by S. aureus, alleviate the blockade of autophagic flow, depress the transcription of MAPK and NF-κB signaling pathways, and inhibit the proliferation of S. aureus in RAW264.7 macrophages.
硒可以减轻金黄色葡萄球菌（S. aureus）感染引起的炎症反应。然而，关于硒对金黄色葡萄球菌感染 RAW264.7 巨噬细胞自噬的作用尚未见报道。本研究旨在阐明硒对金黄色葡萄球菌感染 RAW264.7 巨噬细胞自噬及相关炎症通路（MAPK 和 NF-κB）的影响。用 NaSeO 和金黄色葡萄球菌共同处理 RAW264.7 巨噬细胞。通过 Western blot 检测相关炎症通路（MAPK 和 NF-κB）和自噬相关蛋白的表达。用免疫荧光染色法测量微管结合蛋白轻链 3（LC3）斑点。用透射电子显微镜（TEM）检测金黄色葡萄球菌感染 RAW264.7 巨噬细胞的超微结构。用平板计数法检测 RAW264.7 巨噬细胞中金黄色葡萄球菌的增殖。结果表明，与金黄色葡萄球菌感染组相比，加入硒后 LC3 II 的表达水平增加，p62 的表达水平降低。与金黄色葡萄球菌感染组相比，添加硒后细胞内 LC3 斑点和自噬小体、自噬体和自噬溶酶体增加。与金黄色葡萄球菌感染组相比，加入硒后金黄色葡萄球菌的增殖数量减少。与金黄色葡萄球菌感染组相比，硒能显著抑制 MAPK 和 NF-κB 信号通路关键蛋白的磷酸化。综上所述，硒能促进金黄色葡萄球菌感染的巨噬细胞自噬，减轻自噬流阻断，抑制 MAPK 和 NF-κB 信号通路的转录，抑制 RAW264.7 巨噬细胞中金黄色葡萄球菌的增殖。
