title: Aminoacyl tRNA Synthetase-Interacting Multifunctional Protein 1 Acts as a Novel B Cell-Activating Factor In Vitro and In Vivo.
abstract: Endogenous B cell-activating factors play pivotal roles in defense mechanisms by regulating B cell responses. We previously reported that aminoacyl tRNA synthetase-interacting multifunctional protein 1 (AIMP1) functions as a novel proinflammatory cytokine that activates macrophages and dendritic cells. However, roles of AIMP1 in B cell responses have not been studied. In this study, we investigated the effects of AIMP1 on B cell responses and their underlying mechanisms. AIMP1 induced the expression of surface activation markers on murine B cells and the proliferation of B cells. Additionally, AIMP1 increased the expression of activation-induced deaminase and class switch recombination in B cells. AIMP1 also had synergistic effects on B cell activation when combined with CD40 stimulus. Intracellular signaling experiments showed that AIMP1 activated B cells through a protein kinase C/NF-κB signaling pathway. Importantly, i.v. injection of AIMP1 into mice increased the expression of CD69 on splenic B cells and significantly enhanced Ag-specific Ab production. Taken together, our results show that AIMP1 acts as a novel B cell-activating factor. AIMP1-mediated B cell activation and the involvement of AIMP1 in diseases will provide additional information for therapeutic strategies.
authors: Division of Life Sciences, College of Life Sciences and Biotechnology, Korea University, Seoul 136-701, Republic of Korea.
authors: Myun Soo
authors: MS
authors: Kim
authors: Division of Life Sciences, College of Life Sciences and Biotechnology, Korea University, Seoul 136-701, Republic of Korea tskim@korea.ac.kr.
authors: Tae Sung
authors: TS
authors: Kim
mesh_terms: D000818:Animals; D001402:B-Lymphocytes / Q000276:immunology*; D015153:Blotting, Western; D002469:Cell Separation; D016207:Cytokines / Q000276:immunology*; D005434:Flow Cytometry; D066298:In Vitro Techniques; D008213:Lymphocyte Activation / Q000276:immunology*; D051379:Mice; D008810:Mice, Inbred C57BL; D008856:Microscopy, Fluorescence; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: C514492:Aimp1 protein, mouse; D016207:Cytokines