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Hendrix RD, Ou Y, Davis JE, Odle AK, Groves TR, Allen AR, Childs GV, Barger SW. Alzheimer amyloid-β- peptide disrupts membrane localization of glucose transporter 1 in astrocytes: implications for glucose levels in brain and blood. Neurobiol Aging 2020; 97:73-88. [PMID: 33161213 PMCID: PMC7736209 DOI: 10.1016/j.neurobiolaging.2020.10.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Revised: 08/25/2020] [Accepted: 10/02/2020] [Indexed: 12/12/2022]
Abstract
Alzheimer’s disease (AD) is associated with disturbances in blood glucose regulation, and type-2 diabetes elevates the risk for dementia. A role for amyloid-β peptide (Aβ) in linking these age-related conditions has been proposed, tested primarily in transgenic mouse lines that overexpress mutated amyloid precursor protein (APP). Because APP has its own impacts on glucose regulation, we examined the BRI-Aβ42 line (“Aβ42-tg”), which produces extracellular Aβ1–42 in the CNS without elevation of APP. We also looked for interactions with diet-induced obesity (DIO) resulting from a high-fat, high-sucrose (“western”) diet. Aβ42-tg mice were impaired in both spatial memory and glucose tolerance. Although DIO induced insulin resistance, Aβ1–42 accumulation did not, and the impacts of DIO and Aβ on glucose tolerance were merely additive. Aβ42-tg mice exhibited no significant differences from wild-type in insulin production, body weight, lipidemia, appetite, physical activity, respiratory quotient, an-/orexigenic factors, or inflammatory factors. These negative findings suggested that the phenotype in these mice arose from perturbation of glucose excursion in an insulin-independent tissue. To wit, cerebral cortex of Aβ42-tg mice had reduced glucose utilization, similar to human patients with AD. This was associated with insufficient trafficking of glucose transporter 1 to the plasma membrane in parenchymal brain cells, a finding also documented in human AD tissue. Together, the lower cerebral metabolic rate of glucose and diminished function of parenchymal glucose transporter 1 indicate that aberrant regulation of blood glucose in AD likely reflects a central phenomenon, resulting from the effects of Aβ on cerebral parenchyma, rather than a generalized disruption of hypothalamic or peripheral endocrinology. The involvement of a specific glucose transporter in this deficit provides a new target for the design of AD therapies.
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Affiliation(s)
- Rachel D Hendrix
- Department of Neurobiology & Developmental Sciences, Little Rock, AR, USA
| | - Yang Ou
- Department of Geriatrics, Little Rock, AR, USA
| | - Jakeira E Davis
- Graduate Program in Interdisciplinary Biomedical Sciences, Little Rock, AR, USA
| | - Angela K Odle
- Department of Neurobiology & Developmental Sciences, Little Rock, AR, USA
| | - Thomas R Groves
- Department of Neurobiology & Developmental Sciences, Little Rock, AR, USA
| | - Antiño R Allen
- Department of Neurobiology & Developmental Sciences, Little Rock, AR, USA; Department of Pharmaceutical Sciences, University of Arkansas for Medical Sciences, Little Rock, AR, USA
| | - Gwen V Childs
- Department of Neurobiology & Developmental Sciences, Little Rock, AR, USA
| | - Steven W Barger
- Department of Neurobiology & Developmental Sciences, Little Rock, AR, USA; Department of Geriatrics, Little Rock, AR, USA; Geriatric Research, Education & Clinical Center, Central Arkansas Veterans Healthcare System, Little Rock, AR, USA.
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Abstract
Dendritic spines are the protuberances from the neuronal dendritic shafts that contain excitatory synapses. The morphological and branching variations of the neuronal dendrites within the hippocampus are implicated in cognition and memory formation. There are several approaches to Golgi staining, all of which have been useful for determining the morphological characteristics of dendritic arbors and produce a clear background. The present Golgi-Cox method, (a slight variation of the protocol that is provided with a commercial Golgi staining kit), was designed to assess how a relatively low dose of the chemotherapeutic drug 5-flurouracil (5-Fu) would affect dendritic morphology, the number of spines, and the complexity of arborization within the hippocampus. The 5-Fu significantly modulated the dendritic complexity and decreased the spine density throughout the hippocampus in a region-specific manner. The data presented show that the Golgi staining method effectively stained the mature neurons in the CA1, the CA3, and the dentate gyrus (DG) of the hippocampus. This protocol reports the details for each step so that other researchers can reliably stain tissue throughout the brain with high quality results and minimal troubleshooting.
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Affiliation(s)
- Thomas R Groves
- Division of Radiation Health, University of Arkansas for Medical Sciences; Department of Pharmaceutical Sciences, University of Arkansas for Medical Sciences; Neurobiology & Developmental Sciences, University of Arkansas for Medical Sciences
| | - Jing Wang
- Division of Radiation Health, University of Arkansas for Medical Sciences; Department of Pharmaceutical Sciences, University of Arkansas for Medical Sciences
| | - Marjan Boerma
- Division of Radiation Health, University of Arkansas for Medical Sciences; Department of Pharmaceutical Sciences, University of Arkansas for Medical Sciences
| | - Antiño R Allen
- Division of Radiation Health, University of Arkansas for Medical Sciences; Department of Pharmaceutical Sciences, University of Arkansas for Medical Sciences; Neurobiology & Developmental Sciences, University of Arkansas for Medical Sciences;
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