Down-Regulation of TLR9 Expression Affects the Maturation and Function of Murine Bone Marrow-Derived Dendritic Cells Induced by CpG

• Published in: Cellular & molecular immunology Vol. 6; no. 3; pp. 199 - 205
• Main Authors: Ma, Ling, Zhao, Guangfeng, Hua, Chunyan, Li, Xiaoxi, Zhao, Xiaoyin, Sun, Lingyun, Hou, Yayi
• Format: Journal Article
• Language: English
• Published: China Nature Publishing Group 01.06.2009; Immunology and Reproductive Biology Lab, Medical School & State Key Laboratory of Pharmaceutical Biotechnology, Nanjing University, Nanjing 210093, China%The affiliated Drum Tower Hospital of Nanjing University Medical School Nanjing 210008, China%Immunology and Reproductive Biology Lab, Medical School & State Key Laboratory of Pharmaceutical Biotechnology, Nanjing University, Nanjing 210093, China; Jiangsu Key Laboratory of Molecular Medicine, Nanjing 210093, China
• Subjects: Animals; Blotting, Western; Bone marrow; Bone Marrow Cells - cytology; Bone Marrow Cells - drug effects; Bone Marrow Cells - metabolism; CD40 antigen; CD40 Antigens - metabolism; Cell Proliferation; Cells, Cultured; Coculture Techniques; CpG islands; CpG基序; Dendritic cells; Dendritic Cells - cytology; Dendritic Cells - drug effects; Dendritic Cells - metabolism; Down-regulation; Down-Regulation - drug effects; Endocytosis; Endocytosis - drug effects; Enzyme-Linked Immunosorbent Assay; Flow Cytometry; Gene Expression - drug effects; Histocompatibility Antigens Class II - metabolism; Interleukin 12; Interleukin-12 - metabolism; Lymphocytes T; Major histocompatibility complex; Mice; Mice, Inbred C57BL; Oligodeoxyribonucleotides - pharmacology; Reverse Transcriptase Polymerase Chain Reaction; RNA, Small Interfering - genetics; RNA-mediated interference; siRNA; Spleen - cytology; T-Lymphocytes - cytology; T-Lymphocytes - immunology; TLR9; TLR9 protein; Toll-Like Receptor 9 - genetics; Toll-Like Receptor 9 - immunology; Toll-Like Receptor 9 - metabolism; Toll-like receptors; Toll样受体; Transfection; 小鼠骨髓; 树突状细胞; TLR9; RNA interference; CpG; DC
• ISSN: 1672-7681; 2042-0226
• DOI: 10.1038/cmi.2009.27

Toll-like receptor 9 （TLR9） is expressed intracellularly by dendritic cells （DCs） and specifically recognizes unmethylated CpG motif. Recognition of TLR9 to CpG DNA can induce DC maturation followed by the subsequent immune responses. Here, RNA interference （RNAi） was used to identify the effect of CpG DNA signaling on DC function. The results showed that transfection of DCs with siRNA specific for TLR9 gene significantly down-regulated TLR9 expression. Immature DCs transfected with TLR9 siRNA did not differentiate into mature DCs with exposure to CpG. TLR9 siRNA-treated DCs expressed low levels of MHC II and CD40 without reducing endocytosis. Furthermore, TLR9 siRNA-transfected DCs exhibited a decreased allostimulatory capacity in a lymphocyte proliferation assay and attenuated Thl responses by decreasing IL-12p70 production. Our findings indicate that siRNA in silencing TLR9 gene in DCs may offer a potential tool to study the TLR9-CpG pathway.