title: Toll-Interleukin 1 Receptor domain-containing adaptor protein positively regulates BV2 cell M1 polarization.
abstract: Microglial activation, including classical (M1) and alternative (M2) activation, plays important roles in the development of several central nervous system disorders and promotes tissue reconstruction. Toll-like receptor (TLR)4 is important for microglial polarization. TIR domain-containing adaptor protein (TIRAP) is an intracellular adaptor protein, which is responsible for the early phase of TLR4 activation. The role of TIRAP in BV2 cell M1 polarization is still unknown. In this study, we showed that TIRAP expression is greatly elevated in lipopolysaccharide (LPS)/interferon (IFN)-γ-treated microglia. TIRAP overexpression promoted BV2 microglial M1 polarization by increasing M1-related marker production (inducible nitric oxide synthase, CD86, interleukin-6, interleukin-1β and tumour necrosis factor-α). In contrast, TIRAP knockdown prevented M1-related marker production. Mechanistically, TIRAP could interact with TNF Receptor-Associated Factor 6 (TRAF6) to increase M1-related marker production in TIRAP overexpressed and LPS/IFN-γ-treated BV2 cells. In addition, silencing of TIRAP effectively inhibited the activation of the Transforming Growth Factor-Beta-Activated Kinase 1/I-Kappa-B Kinase /Nuclear Factor of Kappa Light Polypeptide Gene Enhancer in B-Cells (TAK1/IKK/NF-κB) signalling pathway and the phosphorylation of Akt and mitogen-activated protein kinases, which were activated by LPS/IFN-γ stimulation. Thus, our results suggest that TIRAP positively regulated BV2 microglial M1 polarization through TLR4-mediated TAK1/IKK/NF-κB, mitogen-activated protein kinases and Akt signalling pathways.
authors.affiliation: The Jiangsu Key Laboratory of Neuroregeneration, Nantong University, Nantong, 226001, Jiangsu Province, China.
authors.forename: Leilei
authors.initials: L
authors.lastname: Gong
authors.affiliation: Jiangsu Province Key Laboratory for Inflammation and Molecular Drug Target, Medical College of Nantong University, Nantong, 226001, Jiangsu Province, China.
authors.forename: Hanxiang
authors.initials: H
authors.lastname: Wang
authors.affiliation: Jiangsu Province Key Laboratory for Inflammation and Molecular Drug Target, Medical College of Nantong University, Nantong, 226001, Jiangsu Province, China.
authors.forename: Xiaolei
authors.initials: X
authors.lastname: Sun
authors.affiliation: Laboratory Animal Center, Nantong University, Nantong, 226001, Jiangsu Province, China.
authors.forename: Chun
authors.initials: C
authors.lastname: Liu
authors.affiliation: The Jiangsu Key Laboratory of Neuroregeneration, Nantong University, Nantong, 226001, Jiangsu Province, China.
authors.forename: Chengwei
authors.initials: C
authors.lastname: Duan
authors.affiliation: Jiangsu Province Key Laboratory for Inflammation and Molecular Drug Target, Medical College of Nantong University, Nantong, 226001, Jiangsu Province, China.
authors.forename: Rixin
authors.initials: R
authors.lastname: Cai
authors.affiliation: The Jiangsu Key Laboratory of Neuroregeneration, Nantong University, Nantong, 226001, Jiangsu Province, China.
authors.forename: Xingxing
authors.initials: X
authors.lastname: Gu
authors.affiliation: Laboratory Animal Center, Nantong University, Nantong, 226001, Jiangsu Province, China.
authors.forename: Shunxing
authors.initials: S
authors.lastname: Zhu
mesh_terms: D000818:Animals; D002460:Cell Line; D016764:Cell Polarity; D004660:Encephalitis / Q000139:chemically induced / Q000378:metabolism; D051550:I-kappa B Kinase / Q000378:metabolism; D007371:Interferon-gamma / Q000008:administration & dosage; D008070:Lipopolysaccharides; D020930:MAP Kinase Kinase Kinases / Q000378:metabolism; D008562:Membrane Glycoproteins / Q000378:metabolism*; D051379:Mice; D008810:Mice, Inbred C57BL; D017628:Microglia / Q000378:metabolism*; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D016328:NF-kappa B / Q000378:metabolism; D061251:Primary Cell Culture; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D017472:Receptors, Interleukin-1 / Q000378:metabolism*; D015398:Signal Transduction; D051197:Toll-Like Receptor 4 / Q000378:metabolism; D000099151:MAP Kinase Kinase Kinase 7
chemical_list: D051550:I-kappa B Kinase; D007371:Interferon-gamma; D008070:Lipopolysaccharides; D020930:MAP Kinase Kinase Kinases; D008562:Membrane Glycoproteins; D020928:Mitogen-Activated Protein Kinases; D016328:NF-kappa B; D051057:Proto-Oncogene Proteins c-akt; D017472:Receptors, Interleukin-1; D051197:Toll-Like Receptor 4; D000099151:MAP Kinase Kinase Kinase 7; C499045:TIRAP protein, mouse; C493487:Tlr4 protein, mouse; C496562:Ikbkb protein, mouse
keywords: BV2 cells; LPS/IFN-γ; M1 polarization; NF-κB signalling pathways; TIRAP; neuroinflammation