Dodson Matthew, Benavides Gloria A, Darley-Usmar Victor, Zhang Jianhua
Center for Free Radical Biology, University of Alabama at Birmingham, Birmingham, AL, United States.
Department of Pathology, University of Alabama at Birmingham, Birmingham, AL, United States.
Front Aging. 2022 Feb 21;3:812810. doi: 10.3389/fragi.2022.812810. eCollection 2022.
Mitochondrial dysfunction and metabolic decline are prevalent features of aging and age-related disorders, including neurodegeneration. Neurodegenerative diseases are associated with a progressive loss of metabolic homeostasis. This pathogenic decline in metabolism is the result of several factors, including decreased mitochondrial function, increased oxidative stress, inhibited autophagic flux, and altered metabolic substrate availability. One critical metabolite for maintaining neuronal function is glucose, which is utilized by the brain more than any other organ to meet its substantial metabolic demand. Enzymatic conversion of glucose into its downstream metabolites is critical for maintaining neuronal cell growth and overall metabolic homeostasis. Perturbation of glycolysis could significantly hinder neuronal metabolism by affecting key metabolic pathways. Here, we demonstrate that the glucose analogue 2-deoxyglucose (2DG) decreases cell viability, as well as both basal and maximal mitochondrial oxygen consumption in response to the neurotoxic lipid 4-hydroxynonenal (HNE), whereas glucose deprivation has a minimal effect. Furthermore, using a cell permeabilization assay we found that 2DG has a more pronounced effect on HNE-dependent inhibition of mitochondrial complex I and II than glucose deprivation. Importantly, these findings indicate that altered glucose utilization plays a critical role in dictating neuronal survival by regulating the mitochondrial response to electrophilic stress.
线粒体功能障碍和代谢衰退是衰老及与年龄相关疾病(包括神经退行性变)的普遍特征。神经退行性疾病与代谢稳态的逐渐丧失有关。这种病理性的代谢衰退是多种因素导致的结果,包括线粒体功能下降、氧化应激增加、自噬通量受抑制以及代谢底物可用性改变。维持神经元功能的一种关键代谢物是葡萄糖,大脑对葡萄糖的利用率高于其他任何器官,以满足其巨大的代谢需求。葡萄糖向其下游代谢物的酶促转化对于维持神经元细胞生长和整体代谢稳态至关重要。糖酵解的扰动可能通过影响关键代谢途径而显著阻碍神经元代谢。在此,我们证明葡萄糖类似物2-脱氧葡萄糖(2DG)会降低细胞活力,以及响应神经毒性脂质4-羟基壬烯醛(HNE)时的基础和最大线粒体氧消耗,而葡萄糖剥夺的影响则最小。此外,通过细胞通透实验我们发现,与葡萄糖剥夺相比,2DG对HNE依赖的线粒体复合物I和II的抑制作用更为明显。重要的是,这些发现表明葡萄糖利用的改变通过调节线粒体对亲电应激的反应,在决定神经元存活方面起着关键作用。