Arnanz María Andrea, Ferrer María, Grande María Teresa, de Martín Esteban Samuel Ruiz, Ruiz-Pérez Gonzalo, Cravatt Benjamin F, Mostany Ricardo, Lobo Víctor Javier Sánchez-Arévalo, Romero Julián, Martínez-Relimpio Ana María
Faculty of Experimental Sciences, Universidad Francisco de Vitoria, Madrid, Spain.
Departamento de Anatomía Patológica, Instituto de Investigación Hospital 12 de Octubre, Madrid, Spain.
Glia. 2025 Feb;73(2):352-367. doi: 10.1002/glia.24638. Epub 2024 Oct 30.
Neuroinflammation has recently emerged as a crucial factor in Alzheimer's disease (AD) etiopathogenesis. Microglial cells play an important function in the inflammatory response; specifically, the emergence of disease-associated microglia (DAM) has offered new insights into the conflicting perspectives on the detrimental or beneficial roles of microglia. We previously showed that modulating the endocannabinoid tone by fatty acid amide hydrolase (FAAH) inactivation renders beneficial effects in an amyloidosis context, paradoxically accompanied by an exacerbated neuroinflammatory response and the enrichment of DAM population. Here, we aim to elucidate the role of microglial cells in FAAH-lacking mice in the 5xFAD mouse model of AD by using RNA-sequencing analysis, molecular determinations, and morphological studies by using in vivo multiphoton microscopy. FAAH-lacking AD mice displayed upregulated inflammatory genes and exhibited a DAM genetic profile. Conversely, genes linked to AD were downregulated. Depleting microglia using PLX5622 revealed that plaque-associated microglia in FAAH-deficient AD mice had a more stable, ramified morphology and increased Aβ uptake, leading to reduced plaque growth compared to control mice. Importantly, FAAH expression was negligible in microglial cells, thus suggesting a role for FAAH in the cellular interplay in the central nervous system. Our findings show that Faah gene inactivation triggers a hetero-cellular enhancement of microglial function that was paradoxically paralleled by an exacerbated inflammatory response. Taken together, the present data highlight FAAH as a potential therapeutic target in AD.
神经炎症最近已成为阿尔茨海默病(AD)病因发病机制中的一个关键因素。小胶质细胞在炎症反应中发挥着重要作用;具体而言,疾病相关小胶质细胞(DAM)的出现为关于小胶质细胞有害或有益作用的相互矛盾观点提供了新的见解。我们之前表明,通过脂肪酸酰胺水解酶(FAAH)失活来调节内源性大麻素水平在淀粉样变性背景下具有有益作用,矛盾的是,这伴随着神经炎症反应加剧和DAM群体的富集。在这里,我们旨在通过RNA测序分析、分子测定以及使用体内多光子显微镜进行形态学研究,阐明在AD的5xFAD小鼠模型中缺乏FAAH的小鼠体内小胶质细胞的作用。缺乏FAAH的AD小鼠表现出炎症基因上调,并呈现出DAM基因特征。相反,与AD相关的基因被下调。使用PLX5622清除小胶质细胞后发现,与对照小鼠相比,FAAH缺陷型AD小鼠中与斑块相关的小胶质细胞具有更稳定、分支状的形态,并且Aβ摄取增加,导致斑块生长减少。重要的是,FAAH在小胶质细胞中的表达可忽略不计,因此表明FAAH在中枢神经系统的细胞相互作用中发挥作用。我们的研究结果表明,Faah基因失活触发了小胶质细胞功能的异细胞增强,这与炎症反应加剧同时出现,看似矛盾。综上所述,目前的数据突出了FAAH作为AD潜在治疗靶点的地位。
J Neuroinflammation. 2014-6-19