Wang Jiong, Huang Wei-Lin, Liu Rong-Yu
Department of Pulmonary, Anhui Geriatrics Institute, The First Affiliated Hospital of Anhui Medical University, Jixi Road 218, 230022, Hefei, People's Republic of China.
Clin Exp Med. 2009 Mar;9(1):37-43. doi: 10.1007/s10238-008-0017-x. Epub 2008 Oct 25.
The clearance of apoptotic neutrophils by macrophages plays an important role in the process of inflammatory response. In the present study, we examined the ability of macrophages to ingest apoptotic neutrophils after activated by synthetic oligodeoxynucleotides containing CpG motifs (CpG-ODN) in vitro. The results showed that, while CpG-ODN at the experimental concentration had no cytotoxic effect on the viability of macrophages, the percentage of macrophages with ingested apoptotic neutrophils was increased from 23.6 to 42.30% by CpG-ODN stimulation. This effect was silenced when macrophages were treated with the mutation of CpG-ODN motifs. Both the total and cell surface protein of Toll-like receptor 9 (TLR9) expression in macrophages was up-regulated after CpG-ODN stimulation. While chloroquine (CHQ) had no effect on TLR9 expression in macrophages, it abolished the enhanced uptake of apoptotic neutrophils by macrophages. Although CpG-ODN had no significant effect on the IL-6 production, it was able to induce the increase of TNF-alpha protein expression and this effect was inhibited by CHQ pretreatment. Increased TNF-alpha production from macrophages induced by CpG-ODN stimulation was down-regulated after phagocytosis of apoptotic neutrophils. In conclusion, CpG-ODN could enhance the ingestion of apoptotic neutrophils by macrophages via TLR9 accompanied with an increasing in the level of TNF-alpha. After phagocytosis of apoptotic neutrophils, the increased TNF-alpha production from macrophages induced by CpG-ODN stimulation was down-regulated which the implications in the immune response remains for the further study.
巨噬细胞清除凋亡中性粒细胞在炎症反应过程中起重要作用。在本研究中，我们检测了体外经含CpG基序的合成寡脱氧核苷酸（CpG-ODN）激活后巨噬细胞摄取凋亡中性粒细胞的能力。结果显示，虽然实验浓度的CpG-ODN对巨噬细胞活力无细胞毒性作用，但经CpG-ODN刺激后，摄取凋亡中性粒细胞的巨噬细胞百分比从23.6%增加到42.30%。当用CpG-ODN基序突变体处理巨噬细胞时，这种效应消失。CpG-ODN刺激后，巨噬细胞中Toll样受体9（TLR9）表达的总蛋白和细胞表面蛋白均上调。虽然氯喹（CHQ）对巨噬细胞中TLR9表达无影响，但它消除了巨噬细胞对凋亡中性粒细胞摄取的增强作用。虽然CpG-ODN对IL-6产生无显著影响，但它能够诱导TNF-α蛋白表达增加，且这种效应被CHQ预处理所抑制。CpG-ODN刺激诱导的巨噬细胞TNF-α产生增加在吞噬凋亡中性粒细胞后下调。总之，CpG-ODN可通过TLR9增强巨噬细胞对凋亡中性粒细胞的摄取，并伴有TNF-α水平升高。在吞噬凋亡中性粒细胞后，CpG-ODN刺激诱导的巨噬细胞TNF-α产生增加被下调，其在免疫反应中的意义仍有待进一步研究。
