Budny Vanessa, Bodenmann Chantal, Zürcher Kathrin J, Krüger Maik, de Leeuw Sherida M, Weber Rebecca Z, Rust Ruslan, Ravotto Luca, Ruminot Iván, Barros L Felipe, Weber Bruno, Tackenberg Christian
Institute for Regenerative Medicine, University of Zurich, Schlieren, Switzerland.
Neuroscience Center Zurich, University of Zurich and ETH, Zurich, Switzerland.
Front Cell Neurosci. 2025 Sep 1;19:1603657. doi: 10.3389/fncel.2025.1603657. eCollection 2025.
The main genetic risk factor for Alzheimer's disease (AD) is the presence of the apolipoprotein E4 () allele. While increases the risk of developing AD, the allele is protective and is risk-neutral. In the brain, APOE is primarily expressed by astrocytes and plays a key role in various processes including cholesterol and lipid transport, neuronal growth, synaptic plasticity, immune response and energy metabolism. Disruptions in brain energy metabolism are considered a major contributor to AD pathophysiology, raising a key question about how different APOE isoforms affect the energy metabolism of human astrocytes.
In this study, we generated astrocytes (iAstrocytes) from -isogenic human induced pluripotent stem cells (iPSCs), expressing either APOE2, APOE3, APOE4 or carrying an APOE knockout (), and investigated genotype-dependent changes in energy metabolism.
ATP Seahorse assay revealed a reduced mitochondrial and glycolytic ATP production in iAstrocytes. In contrast, glycolysis stress tests demonstrated enhanced glycolysis and glycolytic capacity in iAstrocytes while genetically encoded nanosensor-based FLIM analysis revealed that does not affect lactate dynamics. In agreement with the increased glycolytic activity, iAstrocytes also showed elevated mitochondrial respiration and activity, indicated by proteomic GO enrichment analysis and mitochondrial stress test. This was accompanied by elevated proton leak in iAstrocytes while levels of mitochondrial uncoupling proteins (UCPs) were not affected. Mass spectrometry-based metabolomic analysis identified various energy and glucose metabolism-related pathways that were differentially regulated in compared to the other genotypes, including mitochondrial electron transport chain (ETC) and glycolysis. In general, and iAstrocytes showed a very similar phenotype in all functional assays and differences between / and were stronger than between and .
Our study provides evidence for genotype-dependent effects on astrocyte energy metabolism and highlights alterations in the bioenergetic processes of the brain as important pathomechanisms in AD.
阿尔茨海默病（AD）的主要遗传风险因素是载脂蛋白E4（）等位基因的存在。虽然会增加患AD的风险，但等位基因具有保护作用，而则是风险中性的。在大脑中，APOE主要由星形胶质细胞表达，并在包括胆固醇和脂质运输、神经元生长、突触可塑性、免疫反应和能量代谢等各种过程中发挥关键作用。大脑能量代谢的紊乱被认为是AD病理生理学的主要促成因素，这就提出了一个关键问题，即不同的APOE异构体如何影响人类星形胶质细胞的能量代谢。
在本研究中，我们从 - 同基因人类诱导多能干细胞（iPSC）中生成了星形胶质细胞（iAstrocytes），这些细胞表达APOE2、APOE3、APOE4或携带APOE基因敲除（），并研究了能量代谢中基因型依赖性变化。
ATP海马实验显示，iAstrocytes中线粒体和糖酵解ATP产生减少。相比之下，糖酵解应激测试表明iAstrocytes中的糖酵解和糖酵解能力增强，而基于基因编码纳米传感器的荧光寿命成像分析显示不影响乳酸动力学。与增加的糖酵解活性一致，iAstrocytes还表现出线粒体呼吸和活性升高，蛋白质组学GO富集分析和线粒体应激测试表明了这一点。这伴随着iAstrocytes中质子泄漏增加，而线粒体解偶联蛋白（UCPs）水平不受影响。基于质谱的代谢组学分析确定了与其他基因型相比在中差异调节的各种能量和葡萄糖代谢相关途径，包括线粒体电子传递链（ETC）和糖酵解。总体而言，和iAstrocytes在所有功能测定中表现出非常相似的表型，/与之间的差异比与之间的差异更强。
我们的研究为基因型对星形胶质细胞能量代谢的依赖性影响提供了证据，并强调大脑生物能过程的改变是AD中的重要病理机制。
