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Falangola MF, Nie X, Ward R, McKinnon ET, Dhiman S, Nietert PJ, Helpern JA, Jensen JH. Diffusion MRI detects early brain microstructure abnormalities in 2-month-old 3×Tg-AD mice. NMR Biomed 2020; 33:e4346. [PMID: 32557874 PMCID: PMC7683375 DOI: 10.1002/nbm.4346] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/22/2020] [Revised: 05/08/2020] [Accepted: 05/20/2020] [Indexed: 06/11/2023]
Abstract
The 3×Tg-AD mouse is one of the most studied animal models of Alzheimer's disease (AD), and develops both amyloid beta deposits and neurofibrillary tangles in a temporal and spatial pattern that is similar to human AD pathology. Additionally, abnormal myelination patterns with changes in oligodendrocyte and myelin marker expression are reported to be an early pathological feature in this model. Only few diffusion MRI (dMRI) studies have investigated white matter abnormalities in 3×Tg-AD mice, with inconsistent results. Thus, the goal of this study was to investigate the sensitivity of dMRI to capture brain microstructural alterations in 2-month-old 3×Tg-AD mice. In the fimbria, the fractional anisotropy (FA), kurtosis fractional anisotropy (KFA), and radial kurtosis (K┴ ) were found to be significantly lower in 3×Tg-AD mice than in controls, while the mean diffusivity (MD) and radial diffusivity (D┴ ) were found to be elevated. In the fornix, K┴ was lower for 3×Tg-AD mice; in the dorsal hippocampus MD and D┴ were elevated, as were FA, MD, and D┴ in the ventral hippocampus. These results indicate, for the first time, dMRI changes associated with myelin abnormalities in young 3×Tg-AD mice, before they develop AD pathology. Morphological quantification of myelin basic protein immunoreactivity in the fimbria was significantly lower in the 3×Tg-AD mice compared with the age-matched controls. Our results demonstrate that dMRI is able to detect widespread, significant early brain morphological abnormalities in 2-month-old 3×Tg-AD mice.
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Affiliation(s)
- Maria Fatima Falangola
- Department of Neuroscience, Medical University of South Carolina, Charleston, South Carolina, US
- Center for Biomedical Imaging, Medical University of South Carolina, Charleston, South Carolina, US
| | - Xingju Nie
- Department of Neuroscience, Medical University of South Carolina, Charleston, South Carolina, US
- Center for Biomedical Imaging, Medical University of South Carolina, Charleston, South Carolina, US
| | - Ralph Ward
- Department of Public Health Sciences, Medical University of South Carolina, Charleston, SC, US
| | - Emilie T McKinnon
- Department of Neuroscience, Medical University of South Carolina, Charleston, South Carolina, US
- Department of Neurology, Medical University of South Carolina, Charleston, South Carolina, US
| | - Siddhartha Dhiman
- Department of Neuroscience, Medical University of South Carolina, Charleston, South Carolina, US
| | - Paul J Nietert
- Department of Public Health Sciences, Medical University of South Carolina, Charleston, SC, US
| | - Joseph A Helpern
- Department of Neuroscience, Medical University of South Carolina, Charleston, South Carolina, US
- Center for Biomedical Imaging, Medical University of South Carolina, Charleston, South Carolina, US
| | - Jens H Jensen
- Department of Neuroscience, Medical University of South Carolina, Charleston, South Carolina, US
- Center for Biomedical Imaging, Medical University of South Carolina, Charleston, South Carolina, US
- Department of Radiology and Radiological Science, Medical University of South Carolina, Charleston, South Carolina, US
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Bronzuoli MR, Facchinetti R, Valenza M, Cassano T, Steardo L, Scuderi C. Astrocyte Function Is Affected by Aging and Not Alzheimer's Disease: A Preliminary Investigation in Hippocampi of 3xTg-AD Mice. Front Pharmacol 2019; 10:644. [PMID: 31244658 PMCID: PMC6562169 DOI: 10.3389/fphar.2019.00644] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [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: 02/12/2019] [Accepted: 05/17/2019] [Indexed: 01/12/2023] Open
Abstract
Old age is a risk factor for Alzheimer's disease (AD), which is characterized by hippocampal impairment together with substantial changes in glial cell functions. Are these alterations due to the disease progression or are they a consequence of aging? To start addressing this issue, we studied the expression of specific astrocytic and microglial structural and functional proteins in a validated transgenic model of AD (3×Tg-AD). These mice develop both amyloid plaques and neurofibrillary tangles, and initial signs of the AD-like pathology have been documented as early as three months of age. We compared male 3×Tg-AD mice at 6 and 12 months of age with their wild-type age-matched counterparts. We also investigated neurons by examining the expression of both the microtubule-associated protein 2 (MAP2), a neuronal structural protein, and the brain-derived neurotrophic factor (BDNF). The latter is indeed a crucial indicator for synaptic plasticity and neurogenesis/neurodegeneration. Our results show that astrocytes are more susceptible to aging than microglia, regardless of mouse genotype. Moreover, we discovered significant age-dependent alterations in the expression of proteins responsible for astrocyte-astrocyte and astrocyte-neuron communication, as well as a significant age-dependent decline in BDNF expression. Our data promote further research on the unexplored role of astroglia in both physiological and pathological aging.
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Affiliation(s)
- Maria Rosanna Bronzuoli
- Department of Physiology and Pharmacology "V. Erspamer," Sapienza University of Rome, Rome, Italy
| | - Roberta Facchinetti
- Department of Physiology and Pharmacology "V. Erspamer," Sapienza University of Rome, Rome, Italy
| | - Marta Valenza
- Department of Physiology and Pharmacology "V. Erspamer," Sapienza University of Rome, Rome, Italy.,Epitech Group SpA, Saccolongo, Italy
| | - Tommaso Cassano
- Department of Clinical and Experimental Medicine, University of Foggia, Foggia, Italy
| | - Luca Steardo
- Department of Physiology and Pharmacology "V. Erspamer," Sapienza University of Rome, Rome, Italy
| | - Caterina Scuderi
- Department of Physiology and Pharmacology "V. Erspamer," Sapienza University of Rome, Rome, Italy
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Yang JT, Wang ZJ, Cai HY, Yuan L, Hu MM, Wu MN, Qi JS. Sex Differences in Neuropathology and Cognitive Behavior in APP/PS1/tau Triple-Transgenic Mouse Model of Alzheimer's Disease. Neurosci Bull 2018; 34:736-46. [PMID: 30099679 DOI: 10.1007/s12264-018-0268-9] [Citation(s) in RCA: 65] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2017] [Accepted: 06/16/2018] [Indexed: 10/28/2022] Open
Abstract
Alzheimer's disease (AD) is the most common form of dementia among the elderly, characterized by amyloid plaques, neurofibrillary tangles, and neuroinflammation in the brain, as well as impaired cognitive behaviors. A sex difference in the prevalence of AD has been noted, while sex differences in the cerebral pathology and relevant molecular mechanisms are not well clarified. In the present study, we systematically investigated the sex differences in pathological characteristics and cognitive behavior in 12-month-old male and female APP/PS1/tau triple-transgenic AD mice (3×Tg-AD mice) and examined the molecular mechanisms. We found that female 3×Tg-AD mice displayed more prominent amyloid plaques, neurofibrillary tangles, neuroinflammation, and spatial cognitive deficits than male 3×Tg-AD mice. Furthermore, the expression levels of hippocampal protein kinase A-cAMP response element-binding protein (PKA-CREB) and p38-mitogen-activated protein kinases (MAPK) also showed sex difference in the AD mice, with a significant increase in the levels of p-PKA/p-CREB and a decrease in the p-p38 in female, but not male, 3×Tg-AD mice. We suggest that an estrogen deficiency-induced PKA-CREB-MAPK signaling disorder in 12-month-old female 3×Tg-AD mice might be involved in the serious pathological and cognitive damage in these mice. Therefore, sex differences should be taken into account in investigating AD biomarkers and related target molecules, and estrogen supplementation or PKA-CREB-MAPK stabilization could be beneficial in relieving the pathological damage in AD and improving the cognitive behavior of reproductively-senescent females.
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