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Temporal Appearance of Enhanced Innate Anxiety in Alzheimer Model Mice. Biomedicines 2023; 11:biomedicines11020262. [PMID: 36830799 PMCID: PMC9953677 DOI: 10.3390/biomedicines11020262] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Revised: 01/12/2023] [Accepted: 01/13/2023] [Indexed: 01/20/2023] Open
Abstract
The prevalence of Alzheimer's disorder (AD) is increasing worldwide, and the co-morbid anxiety is an important, albeit often neglected problem, which might appear early during disease development. Animal models can be used to study this question. Mice, as prey animals, show an innate defensive response against a predator odor, providing a valuable tool for anxiety research. Our aim was to test whether the triple-transgenic mice model of AD shows signs of innate anxiety, with specific focus on the temporal appearance of the symptoms. We compared 3xTg-AD mice bearing human mutations of amyloid precursor protein, presenilin 1, and tau with age-matched controls. First, separate age-groups (between 2 and 18 months) were tested for the avoidance of 2-methyl-2-thiazoline, a fox odor component. To test whether hypolocomotion is a general sign of innate anxiety, open-field behavior was subsequently followed monthly in both sexes. The 3xTg-AD mice showed more immobility, approached the fox odor container less often, and spent more time in the avoidance zone. This effect was detectable already in two-month-old animals irrespective of sex, not visible around six months of age, and was more pronounced in aged females than males. The 3xTg-AD animals moved generally less. They also spent less time in the center of the open-field, which was detectable mainly in females older than five months. In contrast to controls, the aged 3xTg-AD was not able to habituate to the arena during a 30-min observation period irrespective of their sex. Amyloid beta and phospho-Tau accumulated gradually in the hippocampus, amygdala, olfactory bulb, and piriform cortex. In conclusion, the early appearance of predator odor- and open space-induced innate anxiety detected already in two-month-old 3xTg-AD mice make this genetically predisposed strain a good model for testing anxiety both before the onset of AD-related symptoms as well as during the later phase. Synaptic dysfunction by protein deposits might contribute to these disturbances.
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Aires V, Ziegler-Waldkirch S, Friesen M, Reichardt W, Erny D, Loreth D, Harborne A, Kretz O, von Elverfeldt D, Meyer-Luehmann M. Seed-induced Aβ deposits in the corpus callosum disrupt white matter integrity in a mouse model of Alzheimer’s disease. Front Cell Neurosci 2022; 16:862918. [PMID: 36003141 PMCID: PMC9393256 DOI: 10.3389/fncel.2022.862918] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2022] [Accepted: 07/18/2022] [Indexed: 11/13/2022] Open
Abstract
Neuropathologically, Alzheimer’s disease (AD) is characterized by the accumulation of amyloid-beta peptide (Aβ) and subsequent formation of the so-called Aβ plaques. Along with neuronal loss, previous studies report white matter anomalies and corpus callosum (CC) atrophy in AD patients. Notably, perturbations in the white matter can be observed years before expected disease onset, suggesting that early stages of disease progression play a role in AD-associated loss of myelin integrity. Through seed-induced deposition of Aβ, we are able to examine alterations of central nervous system (CNS) integrity during the initial stages of plaque formation. In this study, we investigate the impact of Aβ seeding in the CC utilizing various imaging techniques as well as quantitative gene expression analysis and demonstrate that Aβ deposits result in an imbalance of glial cells in the CC. We found increased amounts of phagocytic microglia and reactive astrocytes, while oligodendrocyte progenitor cell (OPC) numbers were reduced. Moreover, white matter aberrations adjacent to the Aβ seeding were observed together with an overall decline in callosal myelination. This data indicate that the initial stages of plaque formation induce oligodendrocyte dysfunction, which might ultimately lead to myelin loss.
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Affiliation(s)
- Vanessa Aires
- Department of Neurology, Medical Center – University of Freiburg, Freiburg, Germany
- Faculty of Medicine, University of Freiburg, Freiburg, Germany
- Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Stephanie Ziegler-Waldkirch
- Department of Neurology, Medical Center – University of Freiburg, Freiburg, Germany
- Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Marina Friesen
- Department of Neurology, Medical Center – University of Freiburg, Freiburg, Germany
- Faculty of Medicine, University of Freiburg, Freiburg, Germany
- Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Wilfried Reichardt
- Faculty of Medicine, University of Freiburg, Freiburg, Germany
- Department of Radiology, Medical Physics, Medical Center – University of Freiburg, Freiburg, Germany
- German Consortium for Translational Cancer Research (DKTK), Heidelberg, Germany
- German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Daniel Erny
- Faculty of Medicine, University of Freiburg, Freiburg, Germany
- Institute of Neuropathology, University of Freiburg, Freiburg, Germany
- Berta-Ottenstein-Programme, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Desiree Loreth
- Department of Neurology, Medical Center – University of Freiburg, Freiburg, Germany
- Faculty of Medicine, University of Freiburg, Freiburg, Germany
- Institute of Cellular and Integrative Physiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Andrew Harborne
- Department of Neurology, Medical Center – University of Freiburg, Freiburg, Germany
- Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Oliver Kretz
- Department of Internal Medicine III, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Dominik von Elverfeldt
- Faculty of Medicine, University of Freiburg, Freiburg, Germany
- Department of Radiology, Medical Physics, Medical Center – University of Freiburg, Freiburg, Germany
| | - Melanie Meyer-Luehmann
- Department of Neurology, Medical Center – University of Freiburg, Freiburg, Germany
- Faculty of Medicine, University of Freiburg, Freiburg, Germany
- Center for Basics in NeuroModulation (NeuroModulBasics), Faculty of Medicine, University of Freiburg, Freiburg, Germany
- *Correspondence: Melanie Meyer-Luehmann,
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