Muramoto Sakura, Shimizu Sachi, Shirakawa Sumika, Ikeda Honoka, Miyamoto Sayaka, Jo Misato, Takemori Uzuki, Morimoto Chiharu, Wu Zhou, Tozaki-Saitoh Hidetoshi, Oda Kosuke, Inoue Erika, Nonaka Saori, Nakanishi Hiroshi
School of Pharmacy, Yasuda Women's University, Hiroshima 731-0153, Japan.
Department of Aging Science and Pharmacology, Faculty of Dental Science, Kyushu University, Fukuoka 812-8582, Japan.
Int J Mol Sci. 2025 Mar 15;26(6):2660. doi: 10.3390/ijms26062660.
Infection with (), which is a major periodontal pathogen, causes a large number of systemic diseases based on chronic inflammation such as diabetes and Alzheimer's disease (AD). However, it is not yet fully understood how can augment local systemic immune and inflammatory responses during progression of AD. There is a strong association between depression and elevated levels of inflammation. Noradrenaline (NA) is a key neurotransmitter that modulates microglial activation during stress conditions. In this study, we have thus investigated the regulatory mechanisms of NA on the production of interleukin-1 (IL-1) by microglia following stimulation with virulence factors, lipopolysaccharide (LPS), and outer membrane vesicles (OMVs). NA (30-1000 nM) significantly enhanced the mRNA level, promoter activity, and protein level of IL-1 up to 20-fold in BV-2 microglia following treatment with LPS (10 μg/mL) and OMVs (150 μg of protein/mL) in a dose-dependent manner. Pharmacological studies have suggested that NA synergistically augments the responses induced by LPS and OMVs through different mechanisms. AP-1 is activated by the adrenergic receptor (AR)-mediated pathway. NF-B, which is activated by the LPS/toll-like receptor 2-mediated pathway, is required for the synergistic effect of NA on the LPS-induced IL-1 production by BV-2 microglia. Co-immunoprecipitation combined with Western blotting and the structural models generated by AlphaFold2 suggested that cross-coupling of NF-B p65 and AP-1 c-Fos transcription factors enhances the binding of NF-B p65 to the IB site, resulting in the synergistic augmentation of the IL-1 promoter activity. In contrast, OMVs were phagocytosed by BV-2 microglia and then activated the TLR9/p52/RelB-mediated pathway. The AR/Epac-mediated pathway, which promotes phagosome maturation, may be responsible for the synergistic effect of NA on the OMV-induced production of IL-1 in BV-2 microglia. Our study provides the first evidence that NA synergistically enhances the production of IL-1 in response to LPS and OMVs through distinct mechanisms.
伴放线聚集杆菌（Aa）感染是一种主要的牙周病原体，会引发大量基于慢性炎症的全身性疾病，如糖尿病和阿尔茨海默病（AD）。然而，关于Aa在AD进展过程中如何增强局部和全身免疫及炎症反应，目前尚未完全了解。抑郁症与炎症水平升高之间存在密切关联。去甲肾上腺素（NA）是一种关键神经递质，在应激条件下调节小胶质细胞的激活。在本研究中，我们因此研究了NA对小胶质细胞在受到Aa毒力因子、脂多糖（LPS）和外膜囊泡（OMV）刺激后白细胞介素-1（IL-1）产生的调控机制。在用10 μg/mL LPS和150 μg蛋白质/mL OMV处理BV-2小胶质细胞后，NA（30 - 1000 nM）以剂量依赖方式显著增强IL-1的mRNA水平、启动子活性和蛋白质水平，最高可达20倍。药理学研究表明，NA通过不同机制协同增强LPS和OMV诱导的反应。AP-1由α-肾上腺素能受体（AR）介导的途径激活。由LPS/ Toll样受体2介导的途径激活的NF-κB，是NA对BV-2小胶质细胞LPS诱导的IL-1产生协同作用所必需的。免疫共沉淀结合蛋白质印迹以及AlphaFold2生成的结构模型表明，NF-κB p65和AP-1 c-Fos转录因子的交叉偶联增强了NF-κB p65与IκB位点的结合，导致IL-1启动子活性的协同增强。相比之下，OMV被BV-2小胶质细胞吞噬，然后激活TLR9/p52/RelB介导的途径。促进吞噬体成熟的AR/Epac介导的途径，可能负责NA对BV-2小胶质细胞OMV诱导的IL-1产生的协同作用。我们的研究提供了首个证据，即NA通过不同机制协同增强对LPS和OMV的IL-1产生。
