Department of Clinical and Toxicological Analyses, School of Pharmaceutical Sciences, University of São Paulo, Av. Prof. Lineu Prestes 580 Bl. 13B, São Paulo 05508-900, Brazil.
Department of Biochemistry, Cardiovascular Research Institute Maastricht, Maastricht University, 616 6200 MD, 6211 CH Maastricht, The Netherlands.
Exp Cell Res. 2018 Jun 15;367(2):282-290. doi: 10.1016/j.yexcr.2018.04.008. Epub 2018 Apr 9.
Annexin A1 (ANXA1) and Translocator Protein-18KDa (TSPO) down-regulate neuroinflammation. We investigated the role of recombinant ANXA1 (rANXA) on TSPO functions on Toll Like Receptor (TLR) activated microglia.
BV-2 cells (murine microglia), were stimulated by E. coli Lipopolysaccharide (LPS) and treated with rANXA1 in order to measure TSPO expression and inflammatory parameters. Anti-sense ANXA1 and TLR4 and TSPO shRNA, as well as pharmacological treatments, were employed to assess the mechanisms involved.
LPS-stimulated BV-2 cells caused overexpression of TSPO, which was inhibited by: pharmacological blockade of TLR4 or TLR4 mRNA silencing; inhibition of myeloid differentiation primary response gene 88 (MyD88) dimerization; or blocking of nuclear factor κB (NF-κB) activation. rANXA1 treatment impaired LPS-induced TSPO upregulation by down-modulating MyD88 and NF-κB signaling; the effect was abolished by WRW4, an antagonist of formyl peptide receptor 2 (FPR2). rANXA1 treatment also downregulated interleukin 1β (IL-1β) and tumor necrosis factor-α (TNFα) secretion in LPS-stimulated BV-2 cells. TSPO knockdown in BV-2 cells augmented LPS-induced TNFα secretion and abolished the inhibitory effect of rANXA1 on TNFα secretion evoked by LPS.
exogenous ANXA1 down-modulates LPS-induced TSPO via MyD-88/NF-κB pathways, and constitutive TSPO is pivotal for the control of ANXA1 on TNFα secretion. TSPO actions may be involved with the mechanisms of ANXA1 on inflammatory brain diseases.
膜联蛋白 A1（ANXA1）和转位蛋白 18kDa（TSPO）下调神经炎症。我们研究了重组 ANXA1（rANXA）对 Toll 样受体（TLR）激活的小胶质细胞中 TSPO 功能的作用。
用大肠杆菌脂多糖（LPS）刺激 BV-2 细胞（鼠小胶质细胞），并用 rANXA1 处理，以测量 TSPO 表达和炎症参数。使用反义 ANXA1 和 TLR4 和 TSPO shRNA 以及药理学治疗来评估所涉及的机制。
LPS 刺激的 BV-2 细胞导致 TSPO 的过表达，这可以通过以下方式抑制：TLR4 或 TLR4 mRNA 沉默的药理学阻断；髓样分化初级反应基因 88（MyD88）二聚化的抑制；或核因子 κB（NF-κB）激活的阻断。rANXA1 处理通过下调 MyD88 和 NF-κB 信号来损害 LPS 诱导的 TSPO 上调；该作用被形式肽受体 2（FPR2）拮抗剂 WRW4 消除。rANXA1 处理还下调 LPS 刺激的 BV-2 细胞中白细胞介素 1β（IL-1β）和肿瘤坏死因子-α（TNFα）的分泌。在 LPS 刺激的 BV-2 细胞中敲低 TSPO 会增加 LPS 诱导的 TNFα 分泌，并消除 rANXA1 对 LPS 诱导的 TNFα 分泌的抑制作用。
外源性 ANXA1 通过 MyD-88/NF-κB 途径下调 LPS 诱导的 TSPO，而组成型 TSPO 是控制 ANXA1 对 TNFα 分泌的关键。TSPO 的作用可能与 ANXA1 在炎症性脑疾病中的作用机制有关。
