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Canet G, Hernandez C, Zussy C, Chevallier N, Desrumaux C, Givalois L. Is AD a Stress-Related Disorder? Focus on the HPA Axis and Its Promising Therapeutic Targets. Front Aging Neurosci 2019; 11:269. [PMID: 31611783 PMCID: PMC6776918 DOI: 10.3389/fnagi.2019.00269] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2019] [Accepted: 09/18/2019] [Indexed: 01/04/2023] Open
Abstract
Alzheimer’s disease (AD) is a progressive neurodegenerative disorder that has important health and economic impacts in the elderly. Despite a better understanding of the molecular mechanisms leading to the appearance of major pathological hallmarks (senile plaques and neurofibrillary tangles), effective treatments are still lacking. Sporadic AD forms (98% of all cases) are multifactorial, and a panoply of risk factors have been identified. While the major risk factor is aging, growing evidence suggests that chronic stress or stress-related disorders increase the probability to develop AD. An early dysregulation of the hypothalamic-pituitary-adrenal axis (HPA axis or stress axis) has been observed in patients. The direct consequence of such perturbation is an oversecretion of glucocorticoids (GC) associated with an impairment of its receptors (glucocorticoid receptors, GR). These steroids hormones easily penetrate the brain and act in synergy with excitatory amino acids. An overexposure could be highly toxic in limbic structures (prefrontal cortex and hippocampus) and contribute in the cognitive decline occurring in AD. GC and GR dysregulations seem to be involved in lots of functions disturbed in AD and a vicious cycle appears, where AD induces HPA axis dysregulation, which in turn potentiates the pathology. This review article presents some preclinical and clinical studies focusing on the HPA axis hormones and their receptors to fight AD. Due to its primordial role in the maintenance of homeostasis, the HPA axis appears as a key-actor in the etiology of AD and a prime target to tackle AD by offering multiple angles of action.
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Affiliation(s)
- Geoffrey Canet
- Molecular Mechanisms in Neurodegenerative Dementia Laboratory (MMDN), INSERM, U1198, Environmental Impact in Alzheimer's Disease and Related Disorders (EiAlz) Team, EPHE, University of Montpellier, Paris, France
| | - Célia Hernandez
- Molecular Mechanisms in Neurodegenerative Dementia Laboratory (MMDN), INSERM, U1198, Environmental Impact in Alzheimer's Disease and Related Disorders (EiAlz) Team, EPHE, University of Montpellier, Paris, France
| | - Charleine Zussy
- Molecular Mechanisms in Neurodegenerative Dementia Laboratory (MMDN), INSERM, U1198, Environmental Impact in Alzheimer's Disease and Related Disorders (EiAlz) Team, EPHE, University of Montpellier, Paris, France
| | - Nathalie Chevallier
- Molecular Mechanisms in Neurodegenerative Dementia Laboratory (MMDN), INSERM, U1198, Environmental Impact in Alzheimer's Disease and Related Disorders (EiAlz) Team, EPHE, University of Montpellier, Paris, France
| | - Catherine Desrumaux
- Molecular Mechanisms in Neurodegenerative Dementia Laboratory (MMDN), INSERM, U1198, Environmental Impact in Alzheimer's Disease and Related Disorders (EiAlz) Team, EPHE, University of Montpellier, Paris, France
| | - Laurent Givalois
- Molecular Mechanisms in Neurodegenerative Dementia Laboratory (MMDN), INSERM, U1198, Environmental Impact in Alzheimer's Disease and Related Disorders (EiAlz) Team, EPHE, University of Montpellier, Paris, France
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Canet G, Chevallier N, Zussy C, Desrumaux C, Givalois L. Central Role of Glucocorticoid Receptors in Alzheimer's Disease and Depression. Front Neurosci 2018; 12:739. [PMID: 30459541 PMCID: PMC6232776 DOI: 10.3389/fnins.2018.00739] [Citation(s) in RCA: 64] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2018] [Accepted: 09/25/2018] [Indexed: 01/21/2023] Open
Abstract
Alzheimer’s disease (AD) is the principal neurodegenerative pathology in the world displaying negative impacts on both the health and social ability of patients and inducing considerable economic costs. In the case of sporadic forms of AD (more than 95% of patients), even if mechanisms are unknown, some risk factors were identified. The principal risk is aging, but there is growing evidence that lifetime events like chronic stress or stress-related disorders may increase the probability to develop AD. This mini-review reinforces the rationale to consider major depressive disorder (MDD) as an important risk factor to develop AD and points the central role played by the hypothalamic-pituitary-adrenal (HPA) axis, glucocorticoids (GC) and their receptors (GR) in the etiology of MDD and AD. Several strategies directly targeting GR were tested to neutralize the HPA axis dysregulation and GC overproduction. Given the ubiquitous expression of GR, antagonists have many undesired side effects, limiting their therapeutic potential. However, a new class of molecules was developed, highly selective and acting as modulators. They present the advantage to selectively abrogate pathogenic GR-dependent processes, while retaining beneficial aspects of GR signaling. In fact, these “selective GR modulators” induce a receptor conformation that allows activation of only a subset of downstream signaling pathways, explaining their capacity to combine agonistic and antagonistic properties. Thus, targeting GR with selective modulators, alone or in association with current strategies, becomes particularly attractive and relevant to develop novel preventive and/or therapeutic strategies to tackle disorders associated with a dysregulation of the HPA axis.
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Affiliation(s)
- Geoffrey Canet
- Molecular Mechanisms in Neurodegenerative Dementia Laboratory, INSERM, U1198, Team Environmental Impact in Alzheimer's Disease and Related Disorders (EiAlz), Montpellier, France.,University of Montpellier, Montpellier, France.,EPHE, Paris, France
| | - Nathalie Chevallier
- Molecular Mechanisms in Neurodegenerative Dementia Laboratory, INSERM, U1198, Team Environmental Impact in Alzheimer's Disease and Related Disorders (EiAlz), Montpellier, France.,University of Montpellier, Montpellier, France.,EPHE, Paris, France
| | - Charleine Zussy
- Molecular Mechanisms in Neurodegenerative Dementia Laboratory, INSERM, U1198, Team Environmental Impact in Alzheimer's Disease and Related Disorders (EiAlz), Montpellier, France.,University of Montpellier, Montpellier, France.,EPHE, Paris, France
| | - Catherine Desrumaux
- Molecular Mechanisms in Neurodegenerative Dementia Laboratory, INSERM, U1198, Team Environmental Impact in Alzheimer's Disease and Related Disorders (EiAlz), Montpellier, France.,University of Montpellier, Montpellier, France.,EPHE, Paris, France
| | - Laurent Givalois
- Molecular Mechanisms in Neurodegenerative Dementia Laboratory, INSERM, U1198, Team Environmental Impact in Alzheimer's Disease and Related Disorders (EiAlz), Montpellier, France.,University of Montpellier, Montpellier, France.,EPHE, Paris, France
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Chan TE, Grossman YS, Bloss EB, Janssen WG, Lou W, McEwen BS, Dumitriu D, Morrison JH. Cell-Type Specific Changes in Glial Morphology and Glucocorticoid Expression During Stress and Aging in the Medial Prefrontal Cortex. Front Aging Neurosci 2018; 10:146. [PMID: 29875653 PMCID: PMC5974224 DOI: 10.3389/fnagi.2018.00146] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2018] [Accepted: 04/30/2018] [Indexed: 12/15/2022] Open
Abstract
Repeated exposure to stressors is known to produce large-scale remodeling of neurons within the prefrontal cortex (PFC). Recent work suggests stress-related forms of structural plasticity can interact with aging to drive distinct patterns of pyramidal cell morphological changes. However, little is known about how other cellular components within PFC might be affected by these challenges. Here, we examined the effects of stress exposure and aging on medial prefrontal cortical glial subpopulations. Interestingly, we found no changes in glial morphology with stress exposure but a profound morphological change with aging. Furthermore, we found an upregulation of non-nuclear glucocorticoid receptors (GR) with aging, while nuclear levels remained largely unaffected. Both changes are selective for microglia, with no stress or aging effect found in astrocytes. Lastly, we show that the changes found within microglia inversely correlated with the density of dendritic spines on layer III pyramidal cells. These findings suggest microglia play a selective role in synaptic health within the aging brain.
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Affiliation(s)
- Thomas E. Chan
- Department of Neuroscience, The Friedman Brain Institute, Mount Sinai School of Medicine, New York, NY, United States
| | - Yael S. Grossman
- Department of Neuroscience, The Friedman Brain Institute, Mount Sinai School of Medicine, New York, NY, United States
| | - Erik B. Bloss
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, United States
| | - William G. Janssen
- Department of Neuroscience, The Friedman Brain Institute, Mount Sinai School of Medicine, New York, NY, United States
| | - Wendy Lou
- Dalla Lana School of Public Health, University of Toronto, Toronto, ON, Canada
| | - Bruce S. McEwen
- Laboratory of Neuroendocrinology, Department of Neuroscience, Rockefeller University, New York, NY, United States
| | - Dani Dumitriu
- Department of Neuroscience, The Friedman Brain Institute, Mount Sinai School of Medicine, New York, NY, United States
| | - John H. Morrison
- Department of Neuroscience, The Friedman Brain Institute, Mount Sinai School of Medicine, New York, NY, United States
- California National Primate Research Center, Department of Neurology, University of California, Davis, Davis, CA, United States
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