Molecular pathophysiology of impaired glucose metabolism, mitochondrial dysfunction, and oxidative DNA damage in Alzheimer's disease brain. (January 2017)

• Record Type: Journal Article
• Authors: Abolhassani, Nona; Leon, Julio; Sheng, Zijing; Oka, Sugako; Hamasaki, Hideomi; Iwaki, Toru; Nakabeppu, Yusaku
• Is Part Of: Mechanisms of ageing and development. Volume 161:Part A(2017)
• Page Start: 95
• Page End: 104
• Publication Date: 2017-01
• Subjects: Alzheimer's disease -- Glucose metabolism -- Mitochondrial dysfunction -- Oxidative DNA damage -- 8-Oxoguanine; Aging -- Periodicals; Developmental biology -- Periodicals; Aging -- Periodicals; Developmental Biology -- Periodicals; Vieillissement -- Périodiques; Biologie du développement -- Périodiques; Aging; Developmental biology; Periodicals; 612.67
• DOI: 10.1016/j.mad.2016.05.005
• Languages: English
• ISSNs: 0047-6374

Abstract

Highlights: In Alzheimer's disease (AD) brain, glucose metabolism and insulin signaling are impaired. Mitochondrial dysfunction and oxidative stress are involved in AD pathology. Oxidative DNA damage may be involved in AD pathology. Abstract: In normal brain, neurons in the cortex and hippocampus produce insulin, which modulates glucose metabolism and cognitive functions. It has been shown that insulin resistance impairs glucose metabolism and mitochondrial function, thus increasing production of reactive oxygen species. Recent progress in Alzheimer's disease (AD) research revealed that insulin production and signaling are severely impaired in AD brain, thereby resulting in mitochondrial dysfunction and increased oxidative stress. Among possible oxidative DNA lesions, 8-oxoguanine (8-oxoG) is highly accumulated in the brain of AD patients. Previously we have shown that incorporating 8-oxoG in nuclear and mitochondrial DNA promotes MUTYH (adenine DNA glycosylase) dependent neurodegeneration. Moreover, cortical neurons prepared from MTH1 (8-oxo-dGTPase)/OGG1 (8-oxoG DNA glycosylase)-double deficient adult mouse brains is shown to exhibit significantly poor neuritogenesis in vitro with increased 8-oxoG accumulation in mitochondrial DNA in the absence of antioxidants. Therefore, 8-oxoG can be considered involved in the neurodegenerative process in AD brain. In mild cognitive impairment, mitochondrial dysfunction and oxidative damage may induce synaptic dysfunction due to energy failures in neurons thus resulting in impaired cognitive function. If such abnormality lasts long, it can lead to vicious cycles of oxidative damage, which may then trigger the neurodegenerative process seen in Alzheimer type dementia.