氧脂质代谢在神经胶质瘤进展和肿瘤微环境中的免疫调节中发挥着重要作用。脂质代谢重编程与巨噬细胞重塑有关，而对氧脂素及其催化酶脂加氧酶在神经胶质瘤相关小胶质细胞/巨噬细胞 (GAM) 调节中的了解在很大程度上仍未得到探索。为了探索氧脂素在人类神经胶质瘤中的病理生理学相关性，我们进行了人胶质瘤和非肿瘤脑组织的超高效液相色谱-MS/MS (UHPLC-MS/MS) 分析。为了全面研究花生四烯酸脂氧合酶 5 (ALOX5) 在神经胶质瘤中的作用，我们对原位神经胶质瘤小鼠的肿瘤进行了体内生物发光成像、免疫荧光染色和流式细胞术分析。我们开发了一种靶向 ALOX5 的纳米抗体，并测试了其与 α 程序性细胞死亡蛋白-1 (PD-1) 联合治疗的抗胶质瘤疗效。在这项研究中，我们发现 ALOX5 及其氧脂素 5-羟基二十碳四烯酸 (5 -HETE）在神经胶质瘤中表达上调，积累程序性死亡配体 1 (PD-L1) M2-GAM 并协调免疫抑制肿瘤微环境。从机制上讲，源自 ALOX5 过表达的胶质瘤细胞的 5-HETE 通过促进核因子红细胞 2 相关因子 2 的核转位，促进 GAM 迁移、PD-L1 表达和 M2 极化。此外，还开发了一种靶向 ALOX5 的纳米抗体，可显着抑制5-HETE 从神经胶质瘤细胞流出，减弱 GAM 的 M2 极化，从而改善神经胶质瘤的进展。此外，ALOX5 靶向纳米抗体与 α-PD-1 的联合治疗表现出优异的抗神经胶质瘤功效。我们的研究结果揭示了 ALOX5/5-HETE 轴在调节 GAM 中的关键作用，并强调 ALOX5 靶向纳米抗体作为潜在的治疗剂，可以增强神经胶质瘤的免疫检查点治疗。© 作者（或其雇主）2024。根据 CC BY-NC 允许重复使用。不得商业再利用。请参阅权利和权限。英国医学杂志出版。

Oxylipin metabolism plays an essential role in glioma progression and immune modulation in the tumor microenvironment. Lipid metabolic reprogramming has been linked to macrophage remodeling, while the understanding of oxylipins and their catalyzed enzymes lipoxygenases in the regulation of glioma-associated microglia/macrophages (GAMs) remains largely unexplored.To explore the pathophysiological relevance of oxylipin in human glioma, we performed Ultra-high performance liquid chromatography-MS/MS (UHPLC-MS/MS) analysis in human glioma and non-tumor brain tissues. To comprehensively investigate the role of arachidonate lipoxygenase 5 (ALOX5) in glioma, we performed in vivo bioluminescent imaging, immunofluorescence staining and flow cytometry analysis on tumors from orthotopic glioma-bearing mice. We developed an ALOX5-targeted nanobody, and tested its anti-glioma efficacy of combination therapy with α-programmed cell death protein-1 (PD-1).In this study, we found that ALOX5 and its oxylipin 5-hydroxyeicosatetraenoic acid (5-HETE) are upregulated in glioma, accumulating programmed death-ligand 1 (PD-L1)+ M2-GAMs and orchestrating an immunosuppressive tumor microenvironment. Mechanistically, 5-HETE derived from ALOX5-overexpressing glioma cells, promotes GAMs migration, PD-L1 expression, and M2 polarization by facilitating nuclear translocation of nuclear factor erythroid 2-related factor 2. Additionally, a nanobody targeting ALOX5 is developed that markedly suppresses 5-HETE efflux from glioma cells, attenuates M2 polarization of GAMs, and consequently ameliorates glioma progression. Furthermore, the combination therapy of the ALOX5-targeted nanobody plus α-PD-1 exhibits superior anti-glioma efficacy.Our findings reveal a pivotal role of the ALOX5/5-HETE axis in regulating GAMs and highlight the ALOX5-targeted nanobody as a potential therapeutic agent, which could potentiate immune checkpoint therapy for glioma.© Author(s) (or their employer(s)) 2024. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.