Institute for Biomedical Research and Innovation, National Research Council, 95126 Catania, Italy.
Section of Human Anatomy and Histology, Department of Biomedical and Biotechnological Sciences, University of Catania, 95123 Catania, Italy.
Cells. 2023 Jul 9;12(14):1813. doi: 10.3390/cells12141813.
Amyotrophic lateral sclerosis (ALS) is a multifactorial neurodegenerative disease characterized by progressive depletion of motor neurons (MNs). Recent evidence suggests a role in ALS pathology for the C-X-C motif chemokine receptor 2 (CXCR2), whose expression was found increased at both mRNA and protein level in cortical neurons of sporadic ALS patients. Previous findings also showed that the receptor inhibition is able to prevent iPSC-derived MNs degeneration in vitro and improve neuromuscular function in SOD1-G93A mice. Here, by performing transcriptional analysis and immunofluorescence studies, we detailed the increased expression and localization of CXCR2 and its main ligand CXCL8 in the human lumbar spinal cord of sporadic ALS patients. We further investigated the functional role of CXCR2/ligands axis in NSC-34 motor neuron-like cells expressing human wild-type (WT) or mutant (G93A) SOD1. A significant expression of CXCR2 was found in doxycycline-induced G93A-SOD1-expressing cells, but not in WT cells. In vitro assays showed CXCR2 activation by GROα and MIP2α, two murine endogenous ligands and functional homologs of CXCL8, reduces cellular viability and triggers apoptosis in a dose dependent manner, while treatment with reparixin, a non-competitive allosteric CXCR2 inhibitor, effectively counteracts GROα and MIP2α toxicity, significantly inhibiting the chemokine-induced cell death. Altogether, data further support a role of CXCR2 axis in ALS etiopathogenesis and confirm its pharmacological modulation as a candidate therapeutic strategy.
肌萎缩侧索硬化症（ALS）是一种多因素神经退行性疾病，其特征是运动神经元（MNs）逐渐耗竭。最近的证据表明，C-X-C 基序趋化因子受体 2（CXCR2）在 ALS 病理中起作用，其在散发性 ALS 患者的皮质神经元中的 mRNA 和蛋白水平均升高。先前的研究结果还表明，受体抑制能够防止 iPSC 衍生的 MN 在体外退化，并改善 SOD1-G93A 小鼠的神经肌肉功能。在这里，通过进行转录分析和免疫荧光研究，我们详细描述了 CXCR2 及其主要配体 CXCL8 在散发性 ALS 患者人类腰椎脊髓中的表达增加和定位。我们进一步研究了 CXCR2/配体轴在表达人野生型（WT）或突变型（G93A）SOD1 的 NSC-34 运动神经元样细胞中的功能作用。在诱导表达 G93A-SOD1 的细胞中发现 CXCR2 的表达显著增加，但在 WT 细胞中没有。体外试验表明，GROα 和 MIP2α（两种鼠内源性配体和 CXCL8 的功能同源物）激活 CXCR2 以剂量依赖的方式降低细胞活力并引发细胞凋亡，而用非竞争性变构 CXCR2 抑制剂 reparixin 处理可有效抵抗 GROα 和 MIP2α 的毒性，显著抑制趋化因子诱导的细胞死亡。总的来说，数据进一步支持 CXCR2 轴在 ALS 发病机制中的作用，并证实其药理学调节作为候选治疗策略。
