Journal of Neuroimmune Pharmacology ( IF 6.2 ) Pub Date : 2021-01-03 , DOI: 10.1007/s11481-020-09976-x Kate O'Reilly 1 , Katherine O'Farrell 1 , Oivind Midttun 2 , Yuliia Rakovets 1 , Jennifer David-Bercholz 1 , Andrew Harkin 1
Brain glia produce neuroactive metabolites via tryptophan-kynurenine catabolism. A role for kynurenine pathway (KP) metabolites is proposed in reactive glial associated neurodegeneration. The aim of this investigation was to assess the role of KP induction and KP metabolites in driving reactive glial associated neuronal atrophy. Rat primary mixed glia, and enriched microglial and astroglial cultures were stimulated with IFNγ (10 ng/ml) for 24 hours. KP induction in mixed glial cells was confirmed by raised expression of the rate limiting KP enzyme indoleamine 2,3 dioxygenase (IDO) and raised concentrations of KP metabolites kynurenic acid (KYNA) and quinolinic acid (QUIN) in the conditioned media. Conditioned media was transferred onto immature (3 days) and mature (21 days) primary cortical neurons in vitro for 24 hours. IFNγ-stimulated mixed glial conditioned media reduced neurite outgrowth and complexity of both immature and mature neurons and co-localised expression of synaptic markers determined by immunocytochemistry. Pre-treatment of mixed glial cells with the IDO inhibitor, 1-methyltryptophan (1-MT) (L) prevented these effects of IFNγ-stimulated mixed glial conditioned media. KYNA increased complexity and synapse formation in mature cortical neurons and protected against reduced neuronal complexity and co-localised expression of synaptic markers induced by conditioned media from IFNγ-stimulated mixed glia and by treatment of neuronal cells with QUIN (1 µM). Overall, this study supports a role for the KP in driving neuronal atrophy associated with reactive glia and indicates that inhibition of the KP in glia, or raising the concentration of the astrocytic metabolite KYNA, protects against reactive microglial and QUIN-associated neuronal atrophy.
Graphical Abstract
中文翻译:
犬尿酸可防止原发性皮层神经元复杂性的反应性神经胶质相关降低
脑胶质细胞通过色氨酸-犬尿氨酸分解代谢产生神经活性代谢物。提出了犬尿氨酸途径 (KP) 代谢物在反应性神经胶质相关神经变性中的作用。本研究的目的是评估 KP 诱导和 KP 代谢物在驱动反应性神经胶质相关神经元萎缩中的作用。用 IFNγ (10 ng/ml) 刺激大鼠原代混合胶质细胞、富集的小胶质细胞和星形胶质细胞培养物 24 小时。混合神经胶质细胞中的 KP 诱导通过提高限速 KP 酶吲哚胺 2,3 双加氧酶 (IDO) 的表达和提高条件培养基中 KP 代谢物犬尿酸 (KYNA) 和喹啉酸 (QUIN) 的浓度来证实。在体外将条件培养基转移到未成熟(3天)和成熟(21天)的初级皮层神经元上24 小时。IFNγ刺激的混合神经胶质条件培养基减少了未成熟和成熟神经元的神经突生长和复杂性,以及免疫细胞化学确定的突触标志物的共定位表达。用 IDO 抑制剂 1-甲基色氨酸 (1-MT) (L) 预处理混合神经胶质细胞可防止 IFNγ 刺激的混合神经胶质条件培养基的这些影响。KYNA 增加成熟皮质神经元的复杂性和突触形成,并防止神经元复杂性降低和突触标志物的共定位表达,这些标志物由来自 IFNγ 刺激的混合神经胶质的条件培养基和用 QUIN (1 µM) 处理的神经元细胞诱导。总体而言,这项研究支持 KP 在驱动与反应性胶质细胞相关的神经元萎缩中的作用,并表明抑制胶质细胞中的 KP,