瑞士乳杆菌通过ROS-Hsp72途径抑制人IECs NF-κB信号通路的免疫调节作用机制

Several studies have shown that reactive oxygen species (ROS) generated by intestinal epithelial cells (IECs) co-cultured with probiotic lactobacilli down-regulated NF-κB activation. However, little is known about mechanisms underlying the inhibitory effects of ROS induced by probiotics on NF-κB sigaling. In our previous study, probiotic Lactobacillus helveticus R0052 down-regulated activation of TNF-α-induced NF-κB signaling in human intestinal epithelial cells (IECs) via ROS. We also found that L. helveticus R0052 induced heat shock protein 72 (Hsp72) expression in a ROS-dependent manner. Hsp72 is known as an anti-inflammatory agent. Based on these findings, we hypothesize that L. helveticus R0052 down-regulates activation of NF-κB signaling via ROS and consequent Hsp72. The over-arching objective of this proposal is to investigate the immunomodulatory mechanisms involved in down-regulation of NF-κB activation of L. helveticus R0052 in IECs. To meet this challenge, objectives to be met include (a) Investigation of effects of L. helveticus R0052 on intracellular ROS level, redox status and Hsp72 gene expression in IECs and (b) Investigation of effects of L. helveticus R0052 on nuclear NF-B activity, degradation of nuclear factor kappa B inhibitor protein-α, and activation of critical upstream kinases of NF-κB signaling in TNF-α-stimulated IECs via ROS and Hsp72. This research will elucidate the modes of L. helveticus immunomodulation on IECs and provide insight into the mechanisms underlying the immunomodulatory actions of probiotics. This research will also extend our understanding the crosstalk between probiotics and IECs.

有研究表明乳杆菌类益生菌诱导人IECs产生的ROS可抑制NF-κB信号通路活化，发挥免疫调节作用，但ROS抑制NF-κB信号通路的作用机制尚未阐明清楚。申请人研究发现，益生菌瑞士乳杆菌R0052诱导人IECs 产生的ROS抑制了NF-κB信号通路的过度活化，并促进了ROS依赖的抗炎分子Hsp72的表达。因此，我们推测瑞士乳杆菌R0052可能通过ROS-Hsp72途径抑制了NF-κB信号通路活化。本项目拟研究瑞士乳杆菌R0052对人IECs胞内ROS水平、细胞氧化还原状态和Hsp72基因表达的影响，以及ROS通过Hsp72对NF-κB核内信号活化、抑制蛋白降解和关键上游激酶活化的影响，探讨瑞士乳杆菌通过ROS-Hsp72途径抑制人IECs NF-κB信号通路的免疫调节作用机理。研究成果可深入阐明益生菌和IECs间相互作用关系，揭示益生菌免疫调节作用机制，具有重要的科学意义。

有研究表明乳杆菌类益生菌诱导人IECs产生的ROS可抑制NF-κB信号通路活化，发挥免疫调节作用，但ROS抑制NF-κB信号通路的作用机制尚未阐明清楚。申请人研究发现，益生菌瑞士乳杆菌R0052诱导人IECs 产生的ROS抑制了NF-κB信号通路的过度活化，并促进了ROS依赖的抗炎分子Hsp72的表达。项目组在国家自然科学基金青年基金“瑞士乳杆菌通过ROS-Hsp72途径抑制人IECs NF-κB信号通路的免疫调节作用机制（31501496）”资助下，研究完成了瑞士乳杆菌R0052对人IECs胞内ROS水平、细胞氧化还原状态和Hsp72基因表达的影响，以及ROS通过Hsp72对NF-κB核内信号活化、抑制蛋白降解和关键上游激酶活化的影响，结果显示瑞士乳杆菌R0052瑞士乳杆菌诱导人IECs 产生的ROS 促进了Hsp72 基因大量表达，瑞士乳杆菌R0052通过ROS-Hsp72途径，抑制了促炎剂TNF-α诱导的NF-κB核内转录活性和p65亚基核转位，从而阻断了NF-κB 核内信号活化；抑制了促炎剂TNF-α诱导的NF-κB 抑制蛋白IκB-α磷酸化和泛素化水平，预防了NF-κB 抑制蛋白IκB-α降解；瑞士乳杆菌诱导人IECs 产生的ROS 通过Hsp72抑制了促炎剂TNF-α诱导的NF-κB 信号通路关键上游激酶TAK1活化。研究阐明了瑞士乳杆菌R0052通过ROS-Hsp72途径抑制人IECs NF-κB信号通路的免疫调节作用机制。研究成果为深入阐明益生菌和IECs间相互作用关系提供了理论依据，具有重要的科学意义。