Recombinant TAT-CD137 Ligand Cytoplasmic Domain Fusion Protein Induces the Production of IL-6 and TNF-alpha in Peritoneal Macrophages.
- Author:
Jung Dae KIM
1
;
Eun Ah LEE
;
Nguyen N QUANG
;
Hong Rae CHO
;
Byungsuk KWON
Author Information
- Publication Type:Original Article
- Keywords: CD137 ligand; CD137; Reverse signaling; TAT; Peritoneal macrophages
- MeSH: 4-1BB Ligand; B-Lymphocytes; Cytokines; Cytoplasm; Dendritic Cells; Interleukin-6; Macrophages; Macrophages, Peritoneal; NF-kappa B; p38 Mitogen-Activated Protein Kinases; Phosphorylation; Proteins; RNA, Messenger; Transcription Factors; Tumor Necrosis Factor-alpha
- From:Immune Network 2011;11(4):216-222
- CountryRepublic of Korea
- Language:English
- Abstract: BACKGROUND: The ligand for CD137 (CD137L; also called 4-1BBL) is mainly expressed on activated APCs such as dendritic cells, B cells and macrophages. Even though CD137L functions as a trigger of the CD137 signaling pathway for T cell activation and expansion, engagement of CD137L can deliver a signal leading to the production of proinflammatory cytokines in macrophages. METHODS: We generated cell-permeable TAT-CD137L cytoplasmic domain fusion protein (TAT-CD137Lct) and examined its ability to initiate the CD137L reverse signaling pathway. RESULTS: Treatment of TAT-CD137Lct induced the production of high levels of IL-6 and TNF-alpha mRNAs and proteins in peritoneal macrophages. TAT-CD137Lct increased phosphorylation of Erk, p38 MAPK and Jnk, and activated transcription factors C/EBP and CREB. However, TAT-CD137Lct did not visibly affect the degradation of the inhibitor of NF-kB (IkBalpha). We further demonstrated that JNK activation was required for TAT-CD137Lct-induced production of TNF-alpha, while activation of Erk and p38 MAPK were involved in IL-6 and TNF-alpha production. CONCLUSION: Our results suggest that TAT-CD137Lct is an effective activator for the CD137L reverse signaling pathway.
