TNFα阻止FGF4介导的人类ALS模型中星形胶质细胞功能障碍和反应性逆转

TNFα prevents FGF4-mediated rescue of astrocyte dysfunction and reactivity in human ALS models

NEUROBIOLOGY OF DISEASE

影响因子:5.6

分区:医学2区 Top / 神经科学2区

发表日期:2024 Oct 15

作者: Erika Velasquez, Ekaterina Savchenko, Sara Marmolejo-Martínez-Artesero, Désiré Challuau, Aline Aebi, Yuriy Pomeshchik, Nuno Jorge Lamas, Mauno Vihinen, Melinda Rezeli, Bernard Schneider, Cedric Raoul, Laurent Roybon

DOI: 10.1016/j.nbd.2024.106687

摘要

星形胶质细胞在肌萎缩侧索硬化症（ALS）的发病和进展中起关键作用，这是一种由中枢神经系统运动神经元（MNs）退行性变引发的致命性疾病。虽然已知ALS的星形胶质细胞对MNs具有毒性，但导致其神经毒性表型的病理变化尚未完全理解。在本研究中，我们利用携带ALS相关A4V突变的诱导多能干细胞（iPSCs）来源的人类星形胶质细胞，观察早期细胞通路和网络变化。蛋白质组分析显示，ALS星形胶质细胞表现出功能障碍和反应性，且与对照组胶质细胞相比存在差异。我们发现，与多种与ALS相关的蛋白及固有免疫cGAS-STING通路有关的蛋白水平发生显著变化。此外，ALS星形胶质细胞的反应性与用肿瘤坏死因子α（TNFα）处理的对照胶质细胞不同。我们评估了成纤维生长因子（FGF）2、4、16和18逆转ALS星形胶质细胞表型的潜力，其中FGF4在体外成功逆转了ALS胶质细胞的功能障碍和反应性。当FGF4被注入ALS模型SOD1G93A小鼠的脊髓时，降低了星形胶质细胞的反应性，但未能充分保护运动神经元免于死亡。进一步分析显示，TNFα抵消了FGF4所实现的反应性降低，提示在体内复杂的神经炎症过程中，FGF4的完全逆转ALS表型受到阻碍。综上所述，我们的数据显示，从ALS iPSCs获得的星形胶质细胞天生具有功能障碍，表现出免疫反应性表型。有效靶向星形胶质细胞的功能障碍和反应性，可能有助于缓解ALS，防止运动神经元死亡。

Abstract

Astrocytes play a crucial role in the onset and progression of amyotrophic lateral sclerosis (ALS), a fatal disorder marked by the degeneration of motor neurons (MNs) in the central nervous system. Although astrocytes in ALS are known to be toxic to MNs, the pathological changes leading to their neurotoxic phenotype remain poorly understood. In this study, we generated human astrocytes from induced pluripotent stem cells (iPSCs) carrying the ALS-associated A4V mutation in superoxide dismutase 1 (SOD1) to examine early cellular pathways and network changes. Proteomic analysis revealed that ALS astrocytes are both dysfunctional and reactive compared to control astrocytes. We identified significant alterations in the levels of proteins linked to ALS pathology and the innate immune cGAS-STING pathway. Furthermore, we found that ALS astrocyte reactivity differs from that of control astrocytes treated with tumor necrosis factor alpha (TNFα), a key cytokine in inflammatory reactions. We then evaluated the potential of fibroblast growth factor (FGF) 2, 4, 16, and 18 to reverse ALS astrocyte phenotype. Among these, FGF4 successfully reversed ALS astrocyte dysfunction and reactivity in vitro. When delivered to the spinal cord of the SOD1G93A mouse model of ALS, FGF4 lowered astrocyte reactivity. However, this was not sufficient to protect MNs from cell death. Further analysis indicated that TNFα abrogated the reactivity reduction achieved by FGF4, suggesting that complete rescue of the ALS phenotype by FGF4 is hindered by ongoing complex neuroinflammatory processes in vivo. In summary, our data demonstrate that astrocytes generated from ALS iPSCs are inherently dysfunctional and exhibit an immune reactive phenotype. Effectively targeting astrocyte dysfunction and reactivity in vivo may help mitigate ALS and prevent MN death.