1
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Miller B, Kim SJ, Cao K, Mehta HH, Thumaty N, Kumagai H, Iida T, McGill C, Pike CJ, Nurmakova K, Levine ZA, Sullivan PM, Yen K, Ertekin-Taner N, Atzmon G, Barzilai N, Cohen P. Humanin variant P3S is associated with longevity in APOE4 carriers and resists APOE4-induced brain pathology. Aging Cell 2024:e14153. [PMID: 38520065 DOI: 10.1111/acel.14153] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2023] [Revised: 03/07/2024] [Accepted: 03/10/2024] [Indexed: 03/25/2024] Open
Abstract
The APOE4 allele is recognized as a significant genetic risk factor to Alzheimer's disease (AD) and influences longevity. Nonetheless, some APOE4 carriers exhibit resistance to AD even in advanced age. Humanin, a mitochondrial-derived peptide comprising 24 amino acids, has variants linked to cognitive resilience and longevity. Our research uncovered a unique humanin variant, P3S, specifically enriched in centenarians with the APOE4 allele. Through in silico analyses and subsequent experimental validation, we demonstrated a strong affinity between humanin P3S and APOE4. Utilizing an APOE4-centric mouse model of amyloidosis (APP/PS1/APOE4), we observed that humanin P3S significantly attenuated brain amyloid-beta accumulation compared to the wild-type humanin. Transcriptomic assessments of mice treated with humanin P3S highlighted its potential mechanism involving the enhancement of amyloid beta phagocytosis. Additionally, in vitro studies corroborated humanin P3S's efficacy in promoting amyloid-beta clearance. Notably, in the temporal cortex of APOE4 carriers, humanin expression is correlated with genes associated with phagocytosis. Our findings suggest a role of the rare humanin variant P3S, especially prevalent among individuals of Ashkenazi descent, in mitigating amyloid beta pathology and facilitating phagocytosis in APOE4-linked amyloidosis, underscoring its significance in longevity and cognitive health among APOE4 carriers.
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Affiliation(s)
- Brendan Miller
- Leonard Davis School of Gerontology, University of Southern California, Los Angeles, California, USA
| | - Su-Jeong Kim
- Leonard Davis School of Gerontology, University of Southern California, Los Angeles, California, USA
| | - Kevin Cao
- Leonard Davis School of Gerontology, University of Southern California, Los Angeles, California, USA
| | - Hemal H Mehta
- Leonard Davis School of Gerontology, University of Southern California, Los Angeles, California, USA
| | - Neehar Thumaty
- Leonard Davis School of Gerontology, University of Southern California, Los Angeles, California, USA
| | - Hiroshi Kumagai
- Leonard Davis School of Gerontology, University of Southern California, Los Angeles, California, USA
| | - Tomomitsu Iida
- Leonard Davis School of Gerontology, University of Southern California, Los Angeles, California, USA
| | - Cassandra McGill
- Leonard Davis School of Gerontology, University of Southern California, Los Angeles, California, USA
| | - Christian J Pike
- Leonard Davis School of Gerontology, University of Southern California, Los Angeles, California, USA
| | - Kamila Nurmakova
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut, USA
| | - Zachary A Levine
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut, USA
- Department of Pathology, Yale School of Medicine, New Haven, Connecticut, USA
| | - Patrick M Sullivan
- Department of Medicine (Geriatrics), Duke University Medical Center, Durham, North Carolina, USA
| | - Kelvin Yen
- Leonard Davis School of Gerontology, University of Southern California, Los Angeles, California, USA
| | | | - Gil Atzmon
- Department of Medicine, Albert Einstein College of Medicine, Bronx, New York, USA
- Department of Biology, Faculty of Natural Sciences, University of Haifa, Haifa, Israel
| | - Nir Barzilai
- Department of Medicine, Albert Einstein College of Medicine, Bronx, New York, USA
| | - Pinchas Cohen
- Leonard Davis School of Gerontology, University of Southern California, Los Angeles, California, USA
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McGill CJ, Christensen A, Qian W, Thorwald MA, Lugo JG, Namvari S, White OS, Finch CE, Benayoun BA, Pike CJ. Protection against APOE4 -associated aging phenotypes with the longevity-promoting intervention 17α-estradiol in male mice. bioRxiv 2024:2024.03.12.584678. [PMID: 38559059 PMCID: PMC10980056 DOI: 10.1101/2024.03.12.584678] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/04/2024]
Abstract
The apolipoprotein ε4 allele ( APOE4 ) is associated with decreased longevity, increased vulnerability to age-related declines, and disorders across multiple systems. Interventions that promote healthspan and lifespan represent a promising strategy to attenuate the development of APOE4 -associated aging phenotypes. Here we studied the ability of the longevity-promoting intervention 17α-estradiol (17αE2) to protect against age-related impairments in APOE4 versus the predominant APOE3 genotype using early middle-aged mice with knock-in of human APOE alleles. Beginning at age 10 months, male APOE3 or APOE4 mice were treated for 20 weeks with 17αE2 or vehicle then compared for indices of aging phenotypes body-wide. Across peripheral and neural measures, APOE4 was associated with poorer outcomes. Notably, 17αE2 treatment improved outcomes in a genotype-dependent manner favoring APOE4 mice. These data demonstrate a positive APOE4 bias in 17αE2-mediated healthspan actions, suggesting that longevity-promoting interventions may be useful in mitigating deleterious age-related risks associated with APOE4 genotype.
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3
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Liu J, Zaidi A, Pike CJ. Microglia/macrophage-specific deletion of TLR-4 protects against neural effects of diet-induced obesity. bioRxiv 2024:2024.02.13.580189. [PMID: 38405877 PMCID: PMC10888944 DOI: 10.1101/2024.02.13.580189] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/27/2024]
Abstract
Obesity is associated with numerous adverse neural effects, including reduced neurogenesis, cognitive impairment, and increased risks for developing Alzheimer's disease (AD) and vascular dementia. Obesity is also characterized by chronic, low-grade inflammation that is implicated in mediating negative consequences body-wide. Toll-like receptor 4 (TLR4) signaling from peripheral macrophages is implicated as an essential regulator of the systemic inflammatory effects of obesity. In the brain, obesity drives chronic neuroinflammation that involves microglial activation, however the contributions of microglia-derived TLR4 signaling to the consequences of obesity are poorly understood. To investigate this issue, we first generated mice that carry an inducible, microglia/macrophage-specific deletion of TLR4 that yields long-term TLR4 knockout only in brain indicating microglial specificity. Next, we analyzed the effects of microglial TLR4 deletion on systemic and neural effects of a 16-week of exposure to control versus obesogenic high-fat diets. In male mice, TLR4 deletion generally yielded limited effects on diet-induced systemic metabolic dysfunction but significantly reduced neuroinflammation and impairments in neurogenesis and cognitive performance. In female mice maintained on obesogenic diet, TLR4 deletion partially protected against weight gain, adiposity, and metabolic impairments. Compared to males, females showed milder diet-induced neural consequences, against which TLR4 deletion was protective. Collectively, these findings demonstrate a central role of microglial TLR4 signaling in mediating the neural effects of obesogenic diet and highlight sexual dimorphic responses to both diet and TLR4.
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Christensen A, Pike CJ. Effects of APOE Genotype and Western Diet on Metabolic Phenotypes in Female Mice. Metabolites 2023; 13:metabo13020287. [PMID: 36837905 PMCID: PMC9959618 DOI: 10.3390/metabo13020287] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2022] [Revised: 02/09/2023] [Accepted: 02/13/2023] [Indexed: 02/18/2023] Open
Abstract
Western diets high in sugars and saturated fats have been reported to induce metabolic and inflammatory impairments that are associated with several age-related disorders, including Alzheimer's disease (AD) and type 2 diabetes (T2D). The apolipoprotein E (APOE) genotype is associated with metabolic and inflammatory outcomes that contribute to risks for AD and T2D, with the APOE4 genotype increasing risks relative to the more common APOE3 allele. In this study, we investigated the impacts of the APOE genotype on systemic and neural effects of the Western diet. Female mice with knock-in of human APOE3 or APOE4 were exposed to control or Western diet for 13 weeks. In the control diet, we observed that APOE4 mice presented with impaired metabolic phenotypes, exhibiting greater adiposity, higher plasma leptin and insulin levels, and poorer glucose clearance than APOE3 mice. Behaviorally, APOE4 mice exhibited worse performance in a hippocampal-dependent learning task. In visceral adipose tissue, APOE4 mice exhibited generally higher expression levels of macrophage- and inflammation-related genes. The cerebral cortex showed a similar pattern, with higher expression of macrophage- and inflammation-related genes in APOE4 than APOE3 mice. Exposure to the Western diet yielded modest, statistically non-significant effects on most metabolic, behavioral, and gene expression measures in both APOE genotypes. Interestingly, the Western diet resulted in reduced gene expression of a few macrophage markers, specifically in APOE4 mice. The observed relative resistance to the Western diet suggests protective roles of both female sex and young adult age. Further, the data demonstrate that APOE4 is associated with deleterious systemic and neural phenotypes and an altered response to a metabolic stressor, findings relevant to the understanding of interactions between the APOE genotype and risks for metabolic disorders.
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5
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Valencia-Olvera AC, Maldonado Weng J, Christensen A, LaDu MJ, Pike CJ. Role of estrogen in women's Alzheimer's disease risk as modified by APOE. J Neuroendocrinol 2023; 35:e13209. [PMID: 36420620 PMCID: PMC10049970 DOI: 10.1111/jne.13209] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/24/2022] [Revised: 09/29/2022] [Accepted: 10/13/2022] [Indexed: 12/15/2022]
Abstract
Alzheimer's disease (AD) is characterized by numerous sexual dimorphisms that impact the development, progression, and probably the strategies to prevent and treat the most common form of dementia. In this review, we consider this topic from a female perspective with a specific focus on how women's vulnerability to the disease is affected by the individual and interactive effects of estrogens and apolipoprotein E (APOE) genotype. Importantly, APOE appears to modulate systemic and neural outcomes of both menopause and estrogen-based hormone therapy. In the brain, dementia risk is greater in APOE4 carriers, and the impacts of hormone therapy on cognitive decline and dementia risk vary according to both outcome measure and APOE genotype. Beyond the CNS, estrogen and APOE genotype affect vulnerability to menopause-associated bone loss, dyslipidemia and cardiovascular disease risk. An emerging concept that may link these relationships is the possibility that the effects of APOE in women interact with estrogen status by mechanisms that may include modulation of estrogen responsiveness. This review highlights the need to consider the key AD risk factors of advancing age in a sex-specific manner to optimize development of therapeutic approaches for AD, a view aligned with the principle of personalized medicine.
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Affiliation(s)
- AC Valencia-Olvera
- Department of Anatomy and Cell Biology, University of Illinois at Chicago, Chicago, IL 60612 USA
| | - J Maldonado Weng
- Department of Anatomy and Cell Biology, University of Illinois at Chicago, Chicago, IL 60612 USA
| | - A Christensen
- Leonard Davis School of Gerontology, University of Southern California, Los Angeles, CA 90089 USA
| | - MJ LaDu
- Department of Anatomy and Cell Biology, University of Illinois at Chicago, Chicago, IL 60612 USA
| | - CJ Pike
- Leonard Davis School of Gerontology, University of Southern California, Los Angeles, CA 90089 USA
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6
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McGill CJ, Christensen A, Qian W, Benayoun BA, Pike CJ. The longevity‐promoting intervention 17α‐Estradiol protects against aging phenotypes in
APOE4
mice. Alzheimers Dement 2022. [DOI: 10.1002/alz.064816] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Affiliation(s)
| | | | - Wenjie Qian
- University of Southern California Los Angeles CA USA
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7
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Rangan P, Lobo F, Parrella E, Rochette N, Morselli M, Stephen TL, Cremonini AL, Tagliafico L, Persia A, Caffa I, Monacelli F, Odetti P, Bonfiglio T, Nencioni A, Pigliautile M, Boccardi V, Mecocci P, Pike CJ, Cohen P, LaDu MJ, Pellegrini M, Xia K, Tran K, Ann B, Chowdhury D, Longo VD. Fasting-mimicking diet cycles reduce neuroinflammation to attenuate cognitive decline in Alzheimer's models. Cell Rep 2022; 40:111417. [PMID: 36170815 PMCID: PMC9648488 DOI: 10.1016/j.celrep.2022.111417] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Revised: 03/30/2022] [Accepted: 09/01/2022] [Indexed: 11/22/2022] Open
Abstract
The effects of fasting-mimicking diet (FMD) cycles in reducing many aging and disease risk factors indicate it could affect Alzheimer's disease (AD). Here, we show that FMD cycles reduce cognitive decline and AD pathology in E4FAD and 3xTg AD mouse models, with effects superior to those caused by protein restriction cycles. In 3xTg mice, long-term FMD cycles reduce hippocampal Aβ load and hyperphosphorylated tau, enhance genesis of neural stem cells, decrease microglia number, and reduce expression of neuroinflammatory genes, including superoxide-generating NADPH oxidase (Nox2). 3xTg mice lacking Nox2 or mice treated with the NADPH oxidase inhibitor apocynin also display improved cognition and reduced microglia activation compared with controls. Clinical data indicate that FMD cycles are feasible and generally safe in a small group of AD patients. These results indicate that FMD cycles delay cognitive decline in AD models in part by reducing neuroinflammation and/or superoxide production in the brain.
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Affiliation(s)
- Priya Rangan
- Longevity Institute, School of Gerontology, Department of Biological Sciences, University of Southern California, 3715 McClintock Avenue, Los Angeles, CA 90089-0191, USA
| | - Fleur Lobo
- Longevity Institute, School of Gerontology, Department of Biological Sciences, University of Southern California, 3715 McClintock Avenue, Los Angeles, CA 90089-0191, USA
| | - Edoardo Parrella
- Longevity Institute, School of Gerontology, Department of Biological Sciences, University of Southern California, 3715 McClintock Avenue, Los Angeles, CA 90089-0191, USA; Department of Molecular and Translational Medicine, University of Brescia, Viale Europa 11, Brescia, BS 25123, Italy
| | - Nicolas Rochette
- Institute for Quantitative and Computational Biosciences, University of California, Los Angeles, 611 Charles E. Young Dr. E., Los Angeles, CA 90095, USA; Department of Ecology and Evolutionary Biology, University of California, Los Angeles, 612 Charles E. Young Dr. E., Los Angeles, CA 90095, USA
| | - Marco Morselli
- Department of Molecular, Cell and Developmental Biology, University of California, Los Angeles, 610 Charles E. Young Dr. S., Los Angeles, CA 90095, USA; Institute for Quantitative and Computational Biosciences, University of California, Los Angeles, 611 Charles E. Young Dr. E., Los Angeles, CA 90095, USA
| | - Terri-Leigh Stephen
- Longevity Institute, School of Gerontology, Department of Biological Sciences, University of Southern California, 3715 McClintock Avenue, Los Angeles, CA 90089-0191, USA
| | - Anna Laura Cremonini
- Department of Internal Medicine and Medical Specialties, University of Genoa, Viale Benedetto XV 6, Genova, GE 16132, Italy; IRCCS Ospedale Policlinico San Martino, Largo Rosanna Benzi 10, 16132 Genoa, Italy
| | - Luca Tagliafico
- Department of Internal Medicine and Medical Specialties, University of Genoa, Viale Benedetto XV 6, Genova, GE 16132, Italy
| | - Angelica Persia
- Department of Internal Medicine and Medical Specialties, University of Genoa, Viale Benedetto XV 6, Genova, GE 16132, Italy
| | - Irene Caffa
- Department of Internal Medicine and Medical Specialties, University of Genoa, Viale Benedetto XV 6, Genova, GE 16132, Italy
| | - Fiammetta Monacelli
- Department of Internal Medicine and Medical Specialties, University of Genoa, Viale Benedetto XV 6, Genova, GE 16132, Italy; IRCCS Ospedale Policlinico San Martino, Largo Rosanna Benzi 10, 16132 Genoa, Italy
| | - Patrizio Odetti
- Department of Internal Medicine and Medical Specialties, University of Genoa, Viale Benedetto XV 6, Genova, GE 16132, Italy; IRCCS Ospedale Policlinico San Martino, Largo Rosanna Benzi 10, 16132 Genoa, Italy
| | - Tommaso Bonfiglio
- Department of Internal Medicine and Medical Specialties, University of Genoa, Viale Benedetto XV 6, Genova, GE 16132, Italy
| | - Alessio Nencioni
- Department of Internal Medicine and Medical Specialties, University of Genoa, Viale Benedetto XV 6, Genova, GE 16132, Italy; IRCCS Ospedale Policlinico San Martino, Largo Rosanna Benzi 10, 16132 Genoa, Italy
| | - Martina Pigliautile
- Santa Maria della Misericordia Hospital, Section of Gerontology and Geriatrics, Department of Medicine and Surgery, University of Perugia, Perugia, Italy
| | - Virginia Boccardi
- Santa Maria della Misericordia Hospital, Section of Gerontology and Geriatrics, Department of Medicine and Surgery, University of Perugia, Perugia, Italy
| | - Patrizia Mecocci
- Santa Maria della Misericordia Hospital, Section of Gerontology and Geriatrics, Department of Medicine and Surgery, University of Perugia, Perugia, Italy
| | - Christian J Pike
- Longevity Institute, School of Gerontology, Department of Biological Sciences, University of Southern California, 3715 McClintock Avenue, Los Angeles, CA 90089-0191, USA
| | - Pinchas Cohen
- Longevity Institute, School of Gerontology, Department of Biological Sciences, University of Southern California, 3715 McClintock Avenue, Los Angeles, CA 90089-0191, USA; USC Dornsife College of Letters, Arts & Sciences, Department of Biological Sciences, University of Southern California, 3551 Trousdale Pkwy., Los Angeles, CA 90089-0191, USA
| | - Mary Jo LaDu
- Department of Anatomy and Cell Biology, University of Illinois at Chicago, Chicago, IL, USA
| | - Matteo Pellegrini
- Department of Molecular, Cell and Developmental Biology, University of California, Los Angeles, 610 Charles E. Young Dr. S., Los Angeles, CA 90095, USA; Institute for Quantitative and Computational Biosciences, University of California, Los Angeles, 611 Charles E. Young Dr. E., Los Angeles, CA 90095, USA
| | - Kyle Xia
- Longevity Institute, School of Gerontology, Department of Biological Sciences, University of Southern California, 3715 McClintock Avenue, Los Angeles, CA 90089-0191, USA
| | - Katelynn Tran
- Longevity Institute, School of Gerontology, Department of Biological Sciences, University of Southern California, 3715 McClintock Avenue, Los Angeles, CA 90089-0191, USA
| | - Brandon Ann
- Longevity Institute, School of Gerontology, Department of Biological Sciences, University of Southern California, 3715 McClintock Avenue, Los Angeles, CA 90089-0191, USA
| | - Dolly Chowdhury
- Longevity Institute, School of Gerontology, Department of Biological Sciences, University of Southern California, 3715 McClintock Avenue, Los Angeles, CA 90089-0191, USA
| | - Valter D Longo
- Longevity Institute, School of Gerontology, Department of Biological Sciences, University of Southern California, 3715 McClintock Avenue, Los Angeles, CA 90089-0191, USA; Eli and Edythe Broad Center for Regenerative Medicine and Stem Cell Research at USC, Keck School of Medicine, University of Southern California, 1425 San Pablo St., Los Angeles, CA 90033, USA; IFOM FIRC Institute of Molecular Oncology, Via Adamello 16, Milano, MI 20139, Italy.
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8
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Yao M, Rosario ER, Soper JC, Pike CJ. Androgens Regulate Tau Phosphorylation Through Phosphatidylinositol 3-Kinase-Protein Kinase B-Glycogen Synthase Kinase 3β Signaling. Neuroscience 2022:S0306-4522(22)00335-9. [PMID: 35777535 PMCID: PMC9797620 DOI: 10.1016/j.neuroscience.2022.06.034] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2022] [Revised: 06/11/2022] [Accepted: 06/23/2022] [Indexed: 12/31/2022]
Abstract
Age-related testosterone depletion in men is a risk factor for Alzheimer's disease (AD). How testosterone modulates AD risk remains to be fully elucidated, although regulation of tau phosphorylation has been suggested as a contributing protective action. To investigate the relationship between testosterone and tau phosphorylation, we first evaluated the effect of androgen status on tau phosphorylation in 3xTg-AD mice. Depletion of endogenous androgens via gonadectomy resulted in increased tau phosphorylation that was prevented by acute testosterone treatment. Parallel alterations in the phosphorylation of both glycogen synthase kinase 3β (GSK3β) and protein kinase B (Akt) suggest possible components of the underlying signaling pathway. To further explore mechanism, primary cultured neurons were treated with a physiological concentration of testosterone or its active metabolite dihydrotestosterone (DHT). Results showed that testosterone and DHT induced significant decreases in phosphorylated tau and significant increases in phosphorylation of Akt and GSK3β. Pharmacological inhibition of phosphatidylinositol 3-kinase (PI3K) effectively inhibited androgen-induced increases in Akt and GSK3β phosphorylation, and decreases in tau phosphorylation. In addition, androgen receptor (AR) knock-down by small interfering RNA prevented androgen-induced changes in the phosphorylation of Akt, GSK3β and tau, suggesting an AR-dependent mechanism. Additional experiments demonstrated androgen-induced changes in Akt, GSK3β and tau phosphorylation in AR-expressing PC12 cells but not in AR-negative PC12 cells. Together, these results suggest an AR-dependent pathway involving PI3K-Akt-GSK3β signaling through which androgens can reduce tau phosphorylation. These findings identify an additional protective mechanism of androgens that can improve neural health and inhibit development of AD.
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Affiliation(s)
- Mingzhong Yao
- Leonard Davis School of Gerontology, University of Southern California, Los Angeles, CA 90089, USA
| | - Emily R Rosario
- Leonard Davis School of Gerontology, University of Southern California, Los Angeles, CA 90089, USA
| | - Jenna Carroll Soper
- Leonard Davis School of Gerontology, University of Southern California, Los Angeles, CA 90089, USA
| | - Christian J Pike
- Leonard Davis School of Gerontology, University of Southern California, Los Angeles, CA 90089, USA.
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9
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Qian W, Christensen A, Lu R, Finch CE, Benayoun BA, Pike CJ. 17alpha‐estradiol improves systemic and neural outcomes in middle‐aged APOE4 mice. Alzheimers Dement 2021. [DOI: 10.1002/alz.054279] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Wenjie Qian
- University of Southern California Los Angeles CA USA
| | | | - Ryan Lu
- University of Southern California Los Angeles CA USA
| | - Caleb E Finch
- USC Leonard Davis School of Gerontology Los Angeles CA USA
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10
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Moser VA, Workman MJ, Hurwitz SJ, Lipman RM, Pike CJ, Svendsen CN. Microglial transcription profiles in mouse and human are driven by APOE4 and sex. iScience 2021; 24:103238. [PMID: 34746703 PMCID: PMC8551075 DOI: 10.1016/j.isci.2021.103238] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2021] [Revised: 06/28/2021] [Accepted: 10/04/2021] [Indexed: 11/22/2022] Open
Abstract
Apolipoprotein E4 (APOE4) is the strongest genetic risk factor for sporadic Alzheimer's disease (AD). APOE4 is known to affect the function of microglia, but to what extent this gene drives microglial gene expression has thus far not been examined. Using a transgenic mouse model of AD that expresses human APOE, we identify a unique transcriptional profile associated with APOE4 expression. We also show a sex and APOE interaction, such that both female sex and APOE4 drive expression of this gene profile. We confirm these findings in human cells, using microglia derived from induced pluripotent stem cells (iMGL). Moreover, we find that these interactions are driven in part by genes related to metal processing, and we show that zinc treatment has APOE genotype-dependent effects on iMGL. These data identify a sex- and APOE4-associated microglial transcription profile and highlight the importance of considering interactive risk factors such as sex and environmental exposures.
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Affiliation(s)
- V. Alexandra Moser
- Board of Governors Regenerative Medicine Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Michael J. Workman
- Board of Governors Regenerative Medicine Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Samantha J. Hurwitz
- Board of Governors Regenerative Medicine Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Rachel M. Lipman
- Board of Governors Regenerative Medicine Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Christian J. Pike
- Leonard Davis School of Gerontology, University of Southern California, Los Angeles, CA, USA
| | - Clive N. Svendsen
- Board of Governors Regenerative Medicine Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA
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11
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Abstract
Studies of Alzheimer's disease (AD) using experimental systems most often involve transgenic mouse models that are characterized by neural accumulation of β-amyloid protein (Aβ), which is widely hypothesized to have a key role in AD pathogenesis. Quantification of Aβ in transgenic mice typically is accomplished through both biochemical and histochemical approaches. In this chapter, we describe two techniques for the histological detection of Aβ, immunostaining with Aβ antibodies and staining with the amyloid dye thioflavin S, and its quantification using digital imaging.
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Affiliation(s)
- Amy Christensen
- Leonard Davis School of Gerontology, University of Southern California, Los Angeles, CA, USA
| | - Christian J Pike
- Leonard Davis School of Gerontology, University of Southern California, Los Angeles, CA, USA.
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12
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Jiang J, Young K, Pike CJ. Higher digit ratio (2D:4D) associated with dementia in women. Alzheimers Dement 2020. [DOI: 10.1002/alz.042277] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Joanne Jiang
- University of Southern California Los Angeles CA USA
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13
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Gatz M, Pike CJ, Beam CR, Reynolds CA. Relative digit length is associated with cognitive abilities in women and men. Alzheimers Dement 2020. [DOI: 10.1002/alz.042328] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Margaret Gatz
- University of Southern California Los Angeles CA USA
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14
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Jiang J, Young K, Pike CJ. Second to fourth digit ratio (2D:4D) is associated with dementia in women. Early Hum Dev 2020; 149:105152. [PMID: 32781308 PMCID: PMC7484057 DOI: 10.1016/j.earlhumdev.2020.105152] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/23/2020] [Revised: 08/03/2020] [Accepted: 08/04/2020] [Indexed: 02/08/2023]
Abstract
Alzheimer's disease is characterized by sex differences that may involve sex hormone exposure during development. Finger length ratios, an indirect measure of prenatal androgen exposure, were found to significantly differ in women with and without dementia. This finding links a relatively feminine in utero development with vulnerability to dementia in women.
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Affiliation(s)
| | | | - Christian J. Pike
- Corresponding Author: Christian J. Pike, Ph.D., Leonard Davis School of Gerontology, University of Southern California, 3715 McClintock Avenue, Los Angeles, CA 90089-0191 USA, Tel: 213-740-4205,
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Luo J, Beam CR, Karlsson IK, Pike CJ, Reynolds CA, Gatz M. Dementia risk in women higher in same-sex than opposite-sex twins. Alzheimers Dement (Amst) 2020; 12:e12049. [PMID: 32582836 PMCID: PMC7306516 DOI: 10.1002/dad2.12049] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/13/2020] [Revised: 05/11/2020] [Accepted: 05/12/2020] [Indexed: 12/27/2022]
Abstract
INTRODUCTION Hormones may be one possible mechanism underlying sex differences in dementia incidence. We examined whether presumed differential prenatal hormone milieu is related to dementia risk by comparing dementia rates in same- and opposite-sex dizygotic twin pairs in male and female twins. METHODS The sample comprised 43,254 individuals from dizygotic twin pairs aged 60 and older from the Swedish Twin Registry. Survival analyses were conducted separately for females and males. RESULTS Female twins from opposite-sex pairs had significantly lower dementia risk than female twins from same-sex pairs, but the differences emerged only after age 70 (hazard ratio = 0.64, P = 0.004). Results were not explained by postnatal risk factors for dementia, and no interaction between twin type and apolipoprotein E (APOE) ε4 was found. Male twins from same-sex versus opposite-sex pairs did not differ significantly. DISCUSSION The results suggest that relatively masculine prenatal hormone milieus correlate with lower dementia risk in females.
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Affiliation(s)
- Jing Luo
- Department of PsychologyUniversity of Southern CaliforniaLos AngelesCaliforniaUSA
| | - Christopher R. Beam
- Department of PsychologyUniversity of Southern CaliforniaLos AngelesCaliforniaUSA
- Leonard Davis School of GerontologyUniversity of Southern CaliforniaLos AngelesCaliforniaUSA
| | - Ida K. Karlsson
- Institute of Gerontology and Aging Research Network – Jönköping (ARN‐J)School of Health and Welfare, Jönköping UniversityJönköpingSweden
- Department of Medical Epidemiology and BiostatisticsKarolinska InstitutetStockholmSweden
| | - Christian J. Pike
- Leonard Davis School of GerontologyUniversity of Southern CaliforniaLos AngelesCaliforniaUSA
| | - Chandra A. Reynolds
- Department of PsychologyUniversity of California, RiversideRiversideCaliforniaUSA
| | - Margaret Gatz
- Department of PsychologyUniversity of Southern CaliforniaLos AngelesCaliforniaUSA
- Leonard Davis School of GerontologyUniversity of Southern CaliforniaLos AngelesCaliforniaUSA
- Department of Medical Epidemiology and BiostatisticsKarolinska InstitutetStockholmSweden
- Center for Economic and Social ResearchUniversity of Southern CaliforniaLos AngelesCaliforniaUSA
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16
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Christensen A, Liu J, Pike CJ. Aging Reduces Estradiol Protection Against Neural but Not Metabolic Effects of Obesity in Female 3xTg-AD Mice. Front Aging Neurosci 2020; 12:113. [PMID: 32431604 PMCID: PMC7214793 DOI: 10.3389/fnagi.2020.00113] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2020] [Accepted: 04/03/2020] [Indexed: 12/29/2022] Open
Abstract
Vulnerability to Alzheimer's disease (AD) is increased by several risk factors, including midlife obesity, female sex, and the depletion of estrogens in women as a consequence of menopause. Conversely, estrogen-based hormone therapies have been linked with protection from age-related increases in adiposity and dementia risk, although treatment efficacy appears to be affected by the age of initiation. Potential interactions between obesity, AD, aging, and estrogen treatment are likely to have significant impact on optimizing the use of hormone therapies in postmenopausal women. In the current study, we compared how treatment with the primary estrogen, 17β-estradiol (E2), affects levels of AD-like neuropathology, behavioral impairment, and other neural and systemic effects of preexisting diet-induced obesity in female 3xTg-AD mice. Importantly, experiments were conducted at chronological ages associated with both the early and late stages of reproductive senescence. We observed that E2 treatment was generally associated with significantly improved metabolic outcomes, including reductions in body weight, adiposity, and leptin, across both age groups. Conversely, neural benefits of E2 in obese mice, including decreased β-amyloid burden, improved behavioral performance, and reduced microglial activation, were observed only in the early aging group. These results are consistent with the perspective that neural benefits of estrogen-based therapies require initiation of treatment during early rather than later phases of reproductive aging. Further, the discordance between E2 protection against systemic versus neural effects of obesity across age groups suggests that pathways other than general metabolic function, perhaps including reduced microglial activation, contribute to the mechanism(s) of the observed E2 actions. These findings reinforce the potential systemic and neural benefits of estrogen therapies against obesity, while also highlighting the critical role of aging as a mediator of estrogens' protective actions.
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Affiliation(s)
| | | | - Christian J. Pike
- Davis School of Gerontology, University of Southern California, Los Angeles, CA, United States
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17
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Luo J, Beam CR, Pike CJ, Gatz M. P3-549: SEX DIFFERENCES IN DEMENTIA RISK: THE EFFECTS OF PRENATAL TESTOSTERONE EXPOSURE, APOE4, AND THEIR INTERACTION. Alzheimers Dement 2019. [DOI: 10.1016/j.jalz.2019.06.3585] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Affiliation(s)
- Jing Luo
- University of Southern California; Los Angeles CA USA
| | | | | | - Margaret Gatz
- University of Southern California; Los Angeles CA USA
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18
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Christensen A, Pike CJ. APOE genotype affects metabolic and Alzheimer-related outcomes induced by Western diet in female EFAD mice. FASEB J 2019; 33:4054-4066. [PMID: 30509127 PMCID: PMC6404574 DOI: 10.1096/fj.201801756r] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2018] [Accepted: 11/05/2018] [Indexed: 01/24/2023]
Abstract
Development of Alzheimer's disease (AD) is regulated by interactive effects of genetic and environmental risk factors. The most significant genetic risk factor for AD is the ε4 allele of apolipoprotein E ( APOE4), which has been shown to exert greater AD risk in women. An important modifiable AD risk factor is obesity and its associated metabolic dysfunctions. Whether APOE genotype might interact with obesity in females to regulate AD pathogenesis is unclear. To investigate this issue, we studied the effects of Western diet (WD) on female EFAD mice, a transgenic mouse model of AD that includes human APOE alleles ε3 (E3FAD) and ε4 (E4FAD). EFAD mice were fed either control (10% fat, 7% sugar) or WD (45% fat, 17% sugar), and both metabolic and neuropathologic outcomes were determined. Although E4FAD mice generally exhibited poorer metabolic status at baseline, E3FAD mice showed greater diet-induced metabolic impairments. Similarly, E4FAD mice exhibited higher levels of AD-related pathology overall, but only E3FAD showed significant increases on select measures of β-amyloid pathology after exposure to WD. These data demonstrate a gene-environment interaction between APOE and obesogenic diets in females. Understanding how AD-promoting effects of obesity are modulated by genetic factors will foster the identification of at-risk populations and development of preventive interventions.-Christensen, A., Pike, C. J. APOE genotype affects metabolic and Alzheimer-related outcomes induced by Western diet in female EFAD mice.
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Affiliation(s)
- Amy Christensen
- Leonard Davis School of Gerontology, University of Southern California, Los Angeles, California, USA
| | - Christian J. Pike
- Leonard Davis School of Gerontology, University of Southern California, Los Angeles, California, USA
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19
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Moser VA, Christensen A, Liu J, Zhou A, Yagi S, Beam CR, Galea L, Pike CJ. Effects of aging, high-fat diet, and testosterone treatment on neural and metabolic outcomes in male brown Norway rats. Neurobiol Aging 2019; 73:145-160. [PMID: 30359877 PMCID: PMC6252085 DOI: 10.1016/j.neurobiolaging.2018.09.016] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2017] [Revised: 07/01/2018] [Accepted: 09/13/2018] [Indexed: 12/23/2022]
Abstract
Risk for Alzheimer's disease (AD) is affected by multiple factors, including aging, obesity, and low testosterone. We previously showed that obesity and low testosterone independently and interactively exacerbate AD-related outcomes in young adult rodents. The goals of the present study are two-fold: to examine whether the effects of an obesogenic diet differ with increasing age and to determine if testosterone treatment in middle-aged and aged animals mitigates negative effects of the diet. Male brown Norway rats were maintained on control or high-fat diets for 12 weeks beginning in young adulthood, middle age, or advanced age. Separate cohorts of middle-aged and aged animals were treated with testosterone during dietary manipulations. Endpoints included metabolic indices, inflammation, cognitive performance, and neural health outcomes. Aging was associated with poorer outcomes that were generally exacerbated by high-fat diet, especially at middle age. Testosterone treatment was largely without benefit, exerting only subtle effects on a select number of measures. Understanding how the deleterious effects of obesity are affected by advancing age and the ability of protective strategies such as testosterone to reduce these effects may provide significant insight into both the development and prevention of age-related cognitive decline and AD.
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Affiliation(s)
- V Alexandra Moser
- Neuroscience Graduate Program, University of Southern California, Los Angeles, CA, USA
| | - Amy Christensen
- Leonard Davis School of Gerontology, University of Southern California, Los Angeles, CA, USA
| | - Jiahui Liu
- Leonard Davis School of Gerontology, University of Southern California, Los Angeles, CA, USA
| | - Amanda Zhou
- Leonard Davis School of Gerontology, University of Southern California, Los Angeles, CA, USA
| | - Shunya Yagi
- Djavad Mowafaghian Centre for Brain Health, Department of Psychology, University of British Columbia, Vancouver BC, Canada
| | - Christopher R Beam
- Department of Psychology, University of Southern California, Los Angeles, CA, USA
| | - Liisa Galea
- Djavad Mowafaghian Centre for Brain Health, Department of Psychology, University of British Columbia, Vancouver BC, Canada
| | - Christian J Pike
- Neuroscience Graduate Program, University of Southern California, Los Angeles, CA, USA; Leonard Davis School of Gerontology, University of Southern California, Los Angeles, CA, USA.
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20
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Moser VA, Uchoa MF, Pike CJ. TLR4 inhibitor TAK-242 attenuates the adverse neural effects of diet-induced obesity. J Neuroinflammation 2018; 15:306. [PMID: 30396359 PMCID: PMC6217784 DOI: 10.1186/s12974-018-1340-0] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [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: 04/05/2018] [Accepted: 10/22/2018] [Indexed: 01/22/2023] Open
Abstract
BACKGROUND Obesity exerts negative effects on brain health, including decreased neurogenesis, impaired learning and memory, and increased risk for Alzheimer's disease and related dementias. Because obesity promotes glial activation, chronic neuroinflammation, and neural injury, microglia are implicated in the deleterious effects of obesity. One pathway that is particularly important in mediating the effects of obesity in peripheral tissues is toll-like receptor 4 (TLR4) signaling. The potential contribution of TLR4 pathways in mediating adverse neural outcomes of obesity has not been well addressed. To investigate this possibility, we examined how pharmacological inhibition of TLR4 affects the peripheral and neural outcomes of diet-induced obesity. METHODS Male C57BL6/J mice were maintained on either a control or high-fat diet for 12 weeks in the presence or absence of the specific TLR4 signaling inhibitor TAK-242. Outcomes examined included metabolic indices, a range of behavioral assessments, microglial activation, systemic and neuroinflammation, and neural health endpoints. RESULTS Peripherally, TAK-242 treatment was associated with partial inhibition of inflammation in the adipose tissue but exerted no significant effects on body weight, adiposity, and a range of metabolic measures. In the brain, obese mice treated with TAK-242 exhibited a significant reduction in microglial activation, improved levels of neurogenesis, and inhibition of Alzheimer-related amyloidogenic pathways. High-fat diet and TAK-242 were associated with only very modest effects on a range of behavioral measures. CONCLUSIONS These results demonstrate a significant protective effect of TLR4 inhibition on neural consequences of obesity, findings that further define the role of microglia in obesity-mediated outcomes and identify a strategy for improving brain health in obese individuals.
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Affiliation(s)
- V. Alexandra Moser
- 0000 0001 2156 6853grid.42505.36Neuroscience Graduate Program, University of Southern California, 3641 Watt Way, HNB 120, Los Angeles, CA 90089 USA
| | - Mariana F. Uchoa
- 0000 0001 2156 6853grid.42505.36Neuroscience Graduate Program, University of Southern California, 3641 Watt Way, HNB 120, Los Angeles, CA 90089 USA
| | - Christian J. Pike
- 0000 0001 2156 6853grid.42505.36Neuroscience Graduate Program, University of Southern California, 3641 Watt Way, HNB 120, Los Angeles, CA 90089 USA ,0000 0001 2156 6853grid.42505.36Leonard Davis School of Gerontology, University of Southern California, 3715 McClintock Avenue, Los Angeles, CA 90089-0191 USA
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21
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Yen K, Wan J, Mehta HH, Miller B, Christensen A, Levine ME, Salomon MP, Brandhorst S, Xiao J, Kim SJ, Navarrete G, Campo D, Harry GJ, Longo V, Pike CJ, Mack WJ, Hodis HN, Crimmins EM, Cohen P. Humanin Prevents Age-Related Cognitive Decline in Mice and is Associated with Improved Cognitive Age in Humans. Sci Rep 2018; 8:14212. [PMID: 30242290 PMCID: PMC6154958 DOI: 10.1038/s41598-018-32616-7] [Citation(s) in RCA: 67] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2018] [Accepted: 09/07/2018] [Indexed: 12/30/2022] Open
Abstract
Advanced age is associated with a decline in cognitive function, likely caused by a combination of modifiable and non-modifiable factors such as genetics and lifestyle choices. Mounting evidence suggests that humanin and other mitochondrial derived peptides play a role in several age-related conditions including neurodegenerative disease. Here we demonstrate that humanin administration has neuroprotective effects in vitro in human cell culture models and is sufficient to improve cognition in vivo in aged mice. Furthermore, in a human cohort, using mitochondrial GWAS, we identified a specific SNP (rs2854128) in the humanin-coding region of the mitochondrial genome that is associated with a decrease in circulating humanin levels. In a large, independent cohort, consisting of a nationally-representative sample of older adults, we find that this SNP is associated with accelerated cognitive aging, supporting the concept that humanin is an important factor in cognitive aging.
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Affiliation(s)
- Kelvin Yen
- Leonard Davis School of Gerontology, University of Southern California, Los Angeles, CA, USA
| | - Junxiang Wan
- Leonard Davis School of Gerontology, University of Southern California, Los Angeles, CA, USA
| | - Hemal H Mehta
- Leonard Davis School of Gerontology, University of Southern California, Los Angeles, CA, USA
| | - Brendan Miller
- Leonard Davis School of Gerontology, University of Southern California, Los Angeles, CA, USA
| | - Amy Christensen
- Leonard Davis School of Gerontology, University of Southern California, Los Angeles, CA, USA
| | - Morgan E Levine
- Department of Pathology, Yale School of Medicine, New Haven, CT, USA
| | - Matthew P Salomon
- Department of Translational Molecular Medicine, John Wayne Cancer Institute at Providence Saint John's Health Center, Santa Monica, CA, USA
| | - Sebastian Brandhorst
- Leonard Davis School of Gerontology, University of Southern California, Los Angeles, CA, USA
| | - Jialin Xiao
- Leonard Davis School of Gerontology, University of Southern California, Los Angeles, CA, USA
| | - Su-Jeong Kim
- Leonard Davis School of Gerontology, University of Southern California, Los Angeles, CA, USA
| | - Gerardo Navarrete
- Leonard Davis School of Gerontology, University of Southern California, Los Angeles, CA, USA
| | - Daniel Campo
- Department of Molecular and Computational Biology, University of Southern California, Los Angeles, CA, USA
| | - G Jean Harry
- Neurotoxicology Group, National Toxicology Program Laboratory, National Institute of Environmental Health Sciences, Research Triangle Park, Triangle Park, NC, USA
| | - Valter Longo
- Leonard Davis School of Gerontology, University of Southern California, Los Angeles, CA, USA
| | - Christian J Pike
- Leonard Davis School of Gerontology, University of Southern California, Los Angeles, CA, USA
| | - Wendy J Mack
- Departments of Medicine and Preventive Medicine, University of Southern California Atherosclerosis Research Unit, University of Southern California, Los Angeles, CA, USA
| | - Howard N Hodis
- Departments of Medicine and Preventive Medicine, University of Southern California Atherosclerosis Research Unit, University of Southern California, Los Angeles, CA, USA
| | - Eileen M Crimmins
- Leonard Davis School of Gerontology, University of Southern California, Los Angeles, CA, USA
| | - Pinchas Cohen
- Leonard Davis School of Gerontology, University of Southern California, Los Angeles, CA, USA.
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22
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Abstract
Alzheimer's disease (AD) pathogenesis is a multifactorial process that involves numerous pathways within the central nervous system. Thus, interventions that interact with several disease-related pathways may offer an increased opportunity for successful prevention and treatment of AD. Translocator protein 18 kD (TSPO) is a mitochondrial protein that is associated with regulation of many cellular processes including inflammation, steroid synthesis, apoptosis, and mitochondrial respiration. Although TSPO ligands have been shown to be protective in several neurodegenerative paradigms, little work has been done to assess their potential as treatments for AD. Female 3xTg-AD mice were administered the TSPO ligand PK11195 once weekly for 5 weeks beginning at 16 months, an age characterized by extensive β-amyloid pathology and behavioral impairments. Animals treated with PK11195 showed improvements in behavior and modest reductions of in both soluble and deposited β-amyloid. The finding that short-term PK11195 treatment was effective in improving both behavioral and pathological outcomes in a model of late-stage AD supports further investigation of TSPO ligands as potential therapeutics for the treatment of AD.
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Affiliation(s)
- Amy Christensen
- Leonard Davis School of Gerontology, University of Southern California, Los Angeles, CA USA
| | - Christian J Pike
- Leonard Davis School of Gerontology, University of Southern California, Los Angeles, CA USA.
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23
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Davies JMS, Cillard J, Friguet B, Cadenas E, Cadet J, Cayce R, Fishmann A, Liao D, Bulteau AL, Derbré F, Rébillard A, Burstein S, Hirsch E, Kloner RA, Jakowec M, Petzinger G, Sauce D, Sennlaub F, Limon I, Ursini F, Maiorino M, Economides C, Pike CJ, Cohen P, Salvayre AN, Halliday MR, Lundquist AJ, Jakowec NA, Mechta-Grigoriou F, Mericskay M, Mariani J, Li Z, Huang D, Grant E, Forman HJ, Finch CE, Sun PY, Pomatto LCD, Agbulut O, Warburton D, Neri C, Rouis M, Cillard P, Capeau J, Rosenbaum J, Davies KJA. The Oxygen Paradox, the French Paradox, and age-related diseases. GeroScience 2017; 39:499-550. [PMID: 29270905 PMCID: PMC5745211 DOI: 10.1007/s11357-017-0002-y] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2017] [Accepted: 11/09/2017] [Indexed: 02/06/2023] Open
Abstract
A paradox is a seemingly absurd or impossible concept, proposition, or theory that is often difficult to understand or explain, sometimes apparently self-contradictory, and yet ultimately correct or true. How is it possible, for example, that oxygen "a toxic environmental poison" could be also indispensable for life (Beckman and Ames Physiol Rev 78(2):547-81, 1998; Stadtman and Berlett Chem Res Toxicol 10(5):485-94, 1997)?: the so-called Oxygen Paradox (Davies and Ursini 1995; Davies Biochem Soc Symp 61:1-31, 1995). How can French people apparently disregard the rule that high dietary intakes of cholesterol and saturated fats (e.g., cheese and paté) will result in an early death from cardiovascular diseases (Renaud and de Lorgeril Lancet 339(8808):1523-6, 1992; Catalgol et al. Front Pharmacol 3:141, 2012; Eisenberg et al. Nat Med 22(12):1428-1438, 2016)?: the so-called, French Paradox. Doubtless, the truth is not a duality and epistemological bias probably generates apparently self-contradictory conclusions. Perhaps nowhere in biology are there so many apparently contradictory views, and even experimental results, affecting human physiology and pathology as in the fields of free radicals and oxidative stress, antioxidants, foods and drinks, and dietary recommendations; this is particularly true when issues such as disease-susceptibility or avoidance, "healthspan," "lifespan," and ageing are involved. Consider, for example, the apparently paradoxical observation that treatment with low doses of a substance that is toxic at high concentrations may actually induce transient adaptations that protect against a subsequent exposure to the same (or similar) toxin. This particular paradox is now mechanistically explained as "Adaptive Homeostasis" (Davies Mol Asp Med 49:1-7, 2016; Pomatto et al. 2017a; Lomeli et al. Clin Sci (Lond) 131(21):2573-2599, 2017; Pomatto and Davies 2017); the non-damaging process by which an apparent toxicant can activate biological signal transduction pathways to increase expression of protective genes, by mechanisms that are completely different from those by which the same agent induces toxicity at high concentrations. In this review, we explore the influences and effects of paradoxes such as the Oxygen Paradox and the French Paradox on the etiology, progression, and outcomes of many of the major human age-related diseases, as well as the basic biological phenomenon of ageing itself.
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Affiliation(s)
- Joanna M S Davies
- The Medical Group, Internal Medicine, Rheumatology & Osteoporosis, Dermatology, Pulmonology, Ophthalmology, and Cardiology; the Hospital of the Good Samaritan, Los Angeles, CA, 90017, USA
- Leonard Davis School of Gerontology of the Ethel Percy Andrus Gerontology Center, University of Southern California, Los Angeles, CA, 90089-0191, USA
| | - Josiane Cillard
- Lab de Biologie Cellulaire et Végétale, Faculté de Pharmacie, Université de Rennes, 35043, Rennes Cedex, France
| | - Bertrand Friguet
- Institut de Biologie Paris-Seine (IBPS), UMR CNRS 8256, Biological Adaptation and Ageing, Sorbonne Universités, UPMC Univ Paris 06, 75005, Paris, France
- INSERM ERL U1164, 75005, Paris, France
| | - Enrique Cadenas
- Leonard Davis School of Gerontology of the Ethel Percy Andrus Gerontology Center, University of Southern California, Los Angeles, CA, 90089-0191, USA
- School of Pharmacy, University of Southern California, Los Angeles, CA, 90089-9121, USA
- Department of Biochemistry & Molecular Medicine, Keck School of Medicine of USC, University of Southern California, Los Angeles, CA, 90033, USA
| | - Jean Cadet
- Département de Médecine nucléaire et Radiobiologie, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, Québec, J1H 5N4, Canada
| | - Rachael Cayce
- The Medical Group, Internal Medicine, Rheumatology & Osteoporosis, Dermatology, Pulmonology, Ophthalmology, and Cardiology; the Hospital of the Good Samaritan, Los Angeles, CA, 90017, USA
| | - Andrew Fishmann
- The Medical Group, Internal Medicine, Rheumatology & Osteoporosis, Dermatology, Pulmonology, Ophthalmology, and Cardiology; the Hospital of the Good Samaritan, Los Angeles, CA, 90017, USA
| | - David Liao
- The Medical Group, Internal Medicine, Rheumatology & Osteoporosis, Dermatology, Pulmonology, Ophthalmology, and Cardiology; the Hospital of the Good Samaritan, Los Angeles, CA, 90017, USA
| | - Anne-Laure Bulteau
- Institut de Génomique Fonctionnelle de Lyon,ENS de Lyon, CNRS, 69364, Lyon Cedex 07, France
| | - Frédéric Derbré
- Laboratory for Movement, Sport and Health Sciences-EA 1274, M2S, Université de Rennes 2-ENS, Bruz, 35170, Rennes, France
| | - Amélie Rébillard
- Laboratory for Movement, Sport and Health Sciences-EA 1274, M2S, Université de Rennes 2-ENS, Bruz, 35170, Rennes, France
| | - Steven Burstein
- The Medical Group, Internal Medicine, Rheumatology & Osteoporosis, Dermatology, Pulmonology, Ophthalmology, and Cardiology; the Hospital of the Good Samaritan, Los Angeles, CA, 90017, USA
| | - Etienne Hirsch
- INSERM UMR 1127-CNRS UMR 7225, Institut du cerveau et de la moelle épinière-ICM Thérapeutique Expérimentale de la Maladie de Parkinson, Université Pierre et Marie Curie, 75651, Paris Cedex 13, France
| | - Robert A Kloner
- Huntington Medical Research Institutes, Pasadena, CA, 91105, USA
| | - Michael Jakowec
- Department of Neurology, Keck School of Medicine, University of Southern California, Los Angeles, CA, 90033, USA
| | - Giselle Petzinger
- Department of Neurology, Keck School of Medicine, University of Southern California, Los Angeles, CA, 90033, USA
| | - Delphine Sauce
- Chronic infections and Immune ageing, INSERM U1135, Hopital Pitie-Salpetriere, Pierre et Marie Curie University, 75013, Paris, France
| | | | - Isabelle Limon
- Institut de Biologie Paris-Seine (IBPS), UMR CNRS 8256, Biological Adaptation and Ageing, Sorbonne Universités, UPMC Univ Paris 06, 75005, Paris, France
| | - Fulvio Ursini
- Department of Molecular Medicine, University of Padova, 35121, Padova, Italy
| | - Matilde Maiorino
- Department of Molecular Medicine, University of Padova, 35121, Padova, Italy
| | - Christina Economides
- Los Angeles Cardiology Associates, Hospital of the Good Samaritan, Los Angeles, CA, 90017, USA
| | - Christian J Pike
- Leonard Davis School of Gerontology of the Ethel Percy Andrus Gerontology Center, University of Southern California, Los Angeles, CA, 90089-0191, USA
- Division of Neurobiology, Department of Biological Sciences of the Dornsife College of Letters, Arts, and Sciences, University of Southern California, Los Angeles, CA, 90089-0191, USA
| | - Pinchas Cohen
- Leonard Davis School of Gerontology of the Ethel Percy Andrus Gerontology Center, University of Southern California, Los Angeles, CA, 90089-0191, USA
- Keck School of Medicine of USC, University of Southern California, Los Angeles, CA, 90033, USA
| | - Anne Negre Salvayre
- Lipid peroxidation, Signalling and Vascular Diseases INSERM U1048, 31432, Toulouse Cedex 4, France
| | - Matthew R Halliday
- Department of Neurology, Keck School of Medicine, University of Southern California, Los Angeles, CA, 90033, USA
| | - Adam J Lundquist
- Department of Neurology, Keck School of Medicine, University of Southern California, Los Angeles, CA, 90033, USA
| | - Nicolaus A Jakowec
- Department of Neurology, Keck School of Medicine, University of Southern California, Los Angeles, CA, 90033, USA
| | | | - Mathias Mericskay
- Laboratoire de Signalisation et Physiopathologie Cardiovasculaire-Inserm UMR-S 1180, Faculté de Pharmacie, Université Paris-Sud, 92296 Châtenay-Malabry, Paris, France
| | - Jean Mariani
- Institut de Biologie Paris-Seine (IBPS), UMR CNRS 8256, Biological Adaptation and Ageing, Sorbonne Universités, UPMC Univ Paris 06, 75005, Paris, France
| | - Zhenlin Li
- Institut de Biologie Paris-Seine (IBPS), UMR CNRS 8256, Biological Adaptation and Ageing, Sorbonne Universités, UPMC Univ Paris 06, 75005, Paris, France
- INSERM ERL U1164, 75005, Paris, France
| | - David Huang
- Department of Radiation Oncology, Hospital of the Good Samaritan, Los Angeles, CA, 90017, USA
| | - Ellsworth Grant
- Department of Oncology & Hematology, Hospital of the Good Samaritan, Los Angeles, CA, 90017, USA
| | - Henry J Forman
- Leonard Davis School of Gerontology of the Ethel Percy Andrus Gerontology Center, University of Southern California, Los Angeles, CA, 90089-0191, USA
| | - Caleb E Finch
- Leonard Davis School of Gerontology of the Ethel Percy Andrus Gerontology Center, University of Southern California, Los Angeles, CA, 90089-0191, USA
- Los Angeles Cardiology Associates, Hospital of the Good Samaritan, Los Angeles, CA, 90017, USA
- Division of Molecular & Computational Biology, Department of Biological Sciences of the Dornsife College of Letters, Arts, and Sciences, University of Southern California, Los Angeles, CA, 90089-0191, USA
| | - Patrick Y Sun
- Leonard Davis School of Gerontology of the Ethel Percy Andrus Gerontology Center, University of Southern California, Los Angeles, CA, 90089-0191, USA
- Division of Molecular & Computational Biology, Department of Biological Sciences of the Dornsife College of Letters, Arts, and Sciences, University of Southern California, Los Angeles, CA, 90089-0191, USA
| | - Laura C D Pomatto
- Leonard Davis School of Gerontology of the Ethel Percy Andrus Gerontology Center, University of Southern California, Los Angeles, CA, 90089-0191, USA
- Division of Molecular & Computational Biology, Department of Biological Sciences of the Dornsife College of Letters, Arts, and Sciences, University of Southern California, Los Angeles, CA, 90089-0191, USA
| | - Onnik Agbulut
- Institut de Biologie Paris-Seine (IBPS), UMR CNRS 8256, Biological Adaptation and Ageing, Sorbonne Universités, UPMC Univ Paris 06, 75005, Paris, France
| | - David Warburton
- Children's Hospital of Los Angeles, Developmental Biology, Regenerative Medicine and Stem Cell Therapeutics program and the Center for Environmental Impact on Global Health Across the Lifespan at The Saban Research Institute, Los Angeles, CA, 90027, USA
- Department of Pediatrics, Keck School of Medicine of USC, University of Southern California, Los Angeles, CA, 90033, USA
| | - Christian Neri
- Institut de Biologie Paris-Seine (IBPS), UMR CNRS 8256, Biological Adaptation and Ageing, Sorbonne Universités, UPMC Univ Paris 06, 75005, Paris, France
| | - Mustapha Rouis
- Institut de Biologie Paris-Seine (IBPS), UMR CNRS 8256, Biological Adaptation and Ageing, Sorbonne Universités, UPMC Univ Paris 06, 75005, Paris, France
- INSERM ERL U1164, 75005, Paris, France
| | - Pierre Cillard
- Lab de Biologie Cellulaire et Végétale, Faculté de Pharmacie, Université de Rennes, 35043, Rennes Cedex, France
| | - Jacqueline Capeau
- DR Saint-Antoine UMR_S938, UPMC, Inserm Faculté de Médecine, Université Pierre et Marie Curie, 75012, Paris, France
| | - Jean Rosenbaum
- Scientific Service of the Embassy of France in the USA, Consulate General of France in Los Angeles, Los Angeles, CA, 90025, USA
| | - Kelvin J A Davies
- Leonard Davis School of Gerontology of the Ethel Percy Andrus Gerontology Center, University of Southern California, Los Angeles, CA, 90089-0191, USA.
- Department of Biochemistry & Molecular Medicine, Keck School of Medicine of USC, University of Southern California, Los Angeles, CA, 90033, USA.
- Division of Molecular & Computational Biology, Department of Biological Sciences of the Dornsife College of Letters, Arts, and Sciences, University of Southern California, Los Angeles, CA, 90089-0191, USA.
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Abstract
Men and women exhibit differences in the development and progression of Alzheimer's disease (AD). The factors underlying the sex differences in AD are not well understood. This Review emphasizes the contributions of sex steroid hormones to the relationship between sex and AD. In women, events that decrease lifetime exposure to estrogens are generally associated with increased AD risk, whereas estrogen-based hormone therapy administered near the time of menopause may reduce AD risk. In men, estrogens do not exhibit age-related reduction and are not significantly associated with AD risk. Rather, normal age-related depletions of testosterone in plasma and brain predict enhanced vulnerability to AD. Both estrogens and androgens exert numerous protective actions in the adult brain that increase neural functioning and resilience as well as specifically attenuating multiple aspects of AD-related neuropathology. Aging diminishes the activational effects of sex hormones in sex-specific manners, which is hypothesized to contribute to the relationship between aging and AD. Sex steroid hormones may also drive sex differences in AD through their organizational effects during developmental sexual differentiation of the brain. Specifically, sex hormone actions during early development may confer inherent vulnerability of the female brain to development of AD in advanced age. The combined effects of organizational and activational effects of sex steroids yield distinct sex differences in AD pathogenesis, a significant variable that must be more rigorously considered in future research. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Christian J Pike
- Leonard Davis School of Gerontology, University of Southern California, Los Angeles, California
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25
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Abstract
Alzheimer's disease (AD) risk is modified by both genetic and environmental risk factors, which are believed to interact to cooperatively modify pathogenesis. Although numerous genetic and environmental risk factors for AD have been identified, relatively little is known about potential gene-environment interactions in regulating disease risk. The strongest genetic risk factor for late-onset AD is the ε4 allele of apolipoprotein E (APOE4). An important modifiable risk factor for AD is obesity, which has been shown to increase AD risk in humans and accelerate development of AD-related pathology in rodent models. Potential interactions between APOE4 and obesity are suggested by the literature but have not been thoroughly investigated. In the current study, we evaluated this relationship by studying the effects of diet-induced obesity (DIO) in the EFAD mouse model, which combines familial AD transgenes with human APOE3 or APOE4. Male E3FAD and E4FAD mice were maintained for 12 weeks on either a control diet or a Western diet high in saturated fat and sugars. We observed that metabolic outcomes of DIO were similar in E3FAD and E4FAD mice. Importantly, our data showed a significant interaction between diet and APOE genotype on AD-related outcomes in which Western diet was associated with robust increases in amyloid deposits, β-amyloid burden, and glial activation in E4FAD but not in E3FAD mice. These findings demonstrate an important gene-environment interaction in an AD mouse model that suggests that AD risk associated with obesity is strongly influenced by APOE genotype.
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Affiliation(s)
- V Alexandra Moser
- Neuroscience Graduate Program, Leonard Davis School of Gerontology, University of Southern California, Los Angeles, CA 90089
| | - Christian J Pike
- Neuroscience Graduate Program, Leonard Davis School of Gerontology, University of Southern California, Los Angeles, CA 90089
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26
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Uchoa MF, Moser VA, Pike CJ. Interactions between inflammation, sex steroids, and Alzheimer's disease risk factors. Front Neuroendocrinol 2016; 43:60-82. [PMID: 27651175 PMCID: PMC5123957 DOI: 10.1016/j.yfrne.2016.09.001] [Citation(s) in RCA: 66] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/02/2016] [Revised: 09/10/2016] [Accepted: 09/14/2016] [Indexed: 12/19/2022]
Abstract
Alzheimer's disease (AD) is an age-related neurodegenerative disorder for which there are no effective strategies to prevent or slow its progression. Because AD is multifactorial, recent research has focused on understanding interactions among the numerous risk factors and mechanisms underlying the disease. One mechanism through which several risk factors may be acting is inflammation. AD is characterized by chronic inflammation that is observed before clinical onset of dementia. Several genetic and environmental risk factors for AD increase inflammation, including apolipoprotein E4, obesity, and air pollution. Additionally, sex steroid hormones appear to contribute to AD risk, with age-related losses of estrogens in women and androgens in men associated with increased risk. Importantly, sex steroid hormones have anti-inflammatory actions and can interact with several other AD risk factors. This review examines the individual and interactive roles of inflammation and sex steroid hormones in AD, as well as their relationships with the AD risk factors apolipoprotein E4, obesity, and air pollution.
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Affiliation(s)
- Mariana F Uchoa
- Neuroscience Graduate Program, University of Southern California, Los Angeles, CA 90089, USA
| | - V Alexandra Moser
- Neuroscience Graduate Program, University of Southern California, Los Angeles, CA 90089, USA
| | - Christian J Pike
- Neuroscience Graduate Program, University of Southern California, Los Angeles, CA 90089, USA; Leonard Davis School of Gerontology, University of Southern California, Los Angeles, CA 90089, USA.
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27
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Moser VA, Pike CJ. Obesity and sex interact in the regulation of Alzheimer's disease. Neurosci Biobehav Rev 2015; 67:102-18. [PMID: 26708713 DOI: 10.1016/j.neubiorev.2015.08.021] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2015] [Revised: 08/01/2015] [Accepted: 08/03/2015] [Indexed: 01/09/2023]
Abstract
Alzheimer's disease (AD) is a progressive neurodegenerative disorder, for which a number of genetic, environmental, and lifestyle risk factors have been identified. A significant modifiable risk factor is obesity in mid-life. Interestingly, both obesity and AD exhibit sex differences and are regulated by sex steroid hormones. Accumulating evidence suggests interactions between obesity and sex in regulation of AD risk, although the pathways underlying this relationship are unclear. Inflammation and the E4 allele of apolipoprotein E have been identified as independent risk factors for AD and both interact with obesity and sex steroid hormones. We review the individual and cooperative effects of obesity and sex on development of AD and examine the potential contributions of apolipoprotein E, inflammation, and their interactions to this relationship.
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Affiliation(s)
- V Alexandra Moser
- Neuroscience Graduate Program, University of Southern California, Los Angeles, CA 90089, USA.
| | - Christian J Pike
- Neuroscience Graduate Program, University of Southern California, Los Angeles, CA 90089, USA; Davis School of Gerontology, University of Southern California, Los Angeles, CA 90089, USA.
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28
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Cacciottolo M, Christensen A, Moser A, Liu J, Pike CJ, Smith C, LaDu MJ, Sullivan PM, Morgan TE, Dolzhenko E, Charidimou A, Wahlund LO, Wiberg MK, Shams S, Chiang GCY, Finch CE. The APOE4 allele shows opposite sex bias in microbleeds and Alzheimer's disease of humans and mice. Neurobiol Aging 2015; 37:47-57. [PMID: 26686669 DOI: 10.1016/j.neurobiolaging.2015.10.010] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2015] [Revised: 10/06/2015] [Accepted: 10/11/2015] [Indexed: 12/21/2022]
Abstract
The apolipoprotein APOE4 allele confers greater risk of Alzheimer's disease (AD) for women than men, in conjunction with greater clinical deficits per unit of AD neuropathology (plaques, tangles). Cerebral microbleeds, which contribute to cognitive dysfunctions during AD, also show APOE4 excess, but sex-APOE allele interactions are not described. We report that elderly men diagnosed for mild cognitive impairment and AD showed a higher risk of cerebral cortex microbleeds with APOE4 allele dose effect in 2 clinical cohorts (ADNI and KIDS). Sex-APOE interactions were further analyzed in EFAD mice carrying human APOE alleles and familial AD genes (5XFAD (+/-) /human APOE(+/+)). At 7 months, E4FAD mice had cerebral cortex microbleeds with female excess, in contrast to humans. Cerebral amyloid angiopathy, plaques, and soluble Aβ also showed female excess. Both the cerebral microbleeds and cerebral amyloid angiopathy increased in proportion to individual Aβ load. In humans, the opposite sex bias of APOE4 allele for microbleeds versus the plaques and tangles is the first example of organ-specific, sex-linked APOE allele effects, and further shows AD as a uniquely human condition.
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Affiliation(s)
- Mafalda Cacciottolo
- Davis School of Gerontology, University of Southern California, Los Angeles, CA, USA
| | - Amy Christensen
- Davis School of Gerontology, University of Southern California, Los Angeles, CA, USA
| | - Alexandra Moser
- Davis School of Gerontology, University of Southern California, Los Angeles, CA, USA
| | - Jiahui Liu
- Davis School of Gerontology, University of Southern California, Los Angeles, CA, USA
| | - Christian J Pike
- Davis School of Gerontology, University of Southern California, Los Angeles, CA, USA
| | - Conor Smith
- Department of Anatomy and Cell Biology, University of Illinois at Chicago, Chicago, IL, USA
| | - Mary Jo LaDu
- Department of Anatomy and Cell Biology, University of Illinois at Chicago, Chicago, IL, USA
| | - Patrick M Sullivan
- Department of Medicine, Duke University, Durham VA Medical Center and GRECC, Durham, NC, USA
| | - Todd E Morgan
- Davis School of Gerontology, University of Southern California, Los Angeles, CA, USA
| | - Egor Dolzhenko
- Department of Molecular and Computational Biology, University of Southern California, Los Angeles, CA, USA
| | - Andreas Charidimou
- Hemorrhagic Stroke Research Program, Department of Neurology, Massachusetts General Hospital Stroke Research Center, Harvard Medical School, Boston, MA, USA
| | - Lars-Olof Wahlund
- Department of Neurobiology, Care Sciences, and Society, Karolinska Institutet, Stockholm, Sweden; Division of Clinical Geriatrics, Karolinska University Hospital, Stockholm, Sweden
| | - Maria Kristofferson Wiberg
- Division of Medical Imaging and Technology, Department of Clinical Science, Intervention, and Technology, Karolinska Institutet, Stockholm, Sweden; Department of Radiology, Karolinska University Hospital, Stockholm, Sweden
| | - Sara Shams
- Division of Medical Imaging and Technology, Department of Clinical Science, Intervention, and Technology, Karolinska Institutet, Stockholm, Sweden; Department of Radiology, Karolinska University Hospital, Stockholm, Sweden
| | | | | | - Caleb E Finch
- Davis School of Gerontology, University of Southern California, Los Angeles, CA, USA; Department of Molecular and Computational Biology, University of Southern California, Los Angeles, CA, USA; Department of Biological Sciences, Dornsife College, University of Southern California, Los Angeles, CA, USA.
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29
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Abstract
Alzheimer’s disease (AD) is a multifactorial neurodegenerative disorder, the development of which is regulated by several environmental and genetic risk factors. Two factors theorized to contribute to the initiation and/or progression of AD pathogenesis are age-related increases in inflammation and obesity. These factors may be particularly problematic in women. The onset of menopause in mid-life elevates the vulnerability of women to AD, an increased risk that is likely associated with the depletion of estrogens. Menopause is also linked with an abundance of additional changes, including increased central adiposity and inflammation. Here, we review the current literature to explore the interactions between obesity, inflammation, menopause and AD.
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Affiliation(s)
- Amy Christensen
- Davis School of Gerontology, University of Southern California Los Angeles, CA, USA
| | - Christian J Pike
- Davis School of Gerontology, University of Southern California Los Angeles, CA, USA
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30
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Yin F, Yao J, Sancheti H, Feng T, Melcangi RC, Morgan TE, Finch CE, Pike CJ, Mack WJ, Cadenas E, Brinton RD. The perimenopausal aging transition in the female rat brain: decline in bioenergetic systems and synaptic plasticity. Neurobiol Aging 2015; 36:2282-2295. [PMID: 25921624 DOI: 10.1016/j.neurobiolaging.2015.03.013] [Citation(s) in RCA: 65] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2014] [Revised: 02/20/2015] [Accepted: 03/25/2015] [Indexed: 01/03/2023]
Abstract
The perimenopause is an aging transition unique to the female that leads to reproductive senescence which can be characterized by multiple neurological symptoms. To better understand potential underlying mechanisms of neurological symptoms of perimenopause, the present study determined genomic, biochemical, brain metabolic, and electrophysiological transformations that occur during this transition using a rat model recapitulating fundamental characteristics of the human perimenopause. Gene expression analyses indicated two distinct aging programs: chronological and endocrine. A critical period emerged during the endocrine transition from regular to irregular cycling characterized by decline in bioenergetic gene expression, confirmed by deficits in fluorodeoxyglucose-positron emission tomography (FDG-PET) brain metabolism, mitochondrial function, and long-term potentiation. Bioinformatic analysis predicted insulin/insulin-like growth factor 1 and adenosine monophosphate-activated protein kinase/peroxisome proliferator-activated receptor gamma coactivator 1 alpha (AMPK/PGC1α) signaling pathways as upstream regulators. Onset of acyclicity was accompanied by a rise in genes required for fatty acid metabolism, inflammation, and mitochondrial function. Subsequent chronological aging resulted in decline of genes required for mitochondrial function and β-amyloid degradation. Emergence of glucose hypometabolism and impaired synaptic function in brain provide plausible mechanisms of neurological symptoms of perimenopause and may be predictive of later-life vulnerability to hypometabolic conditions such as Alzheimer's.
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Affiliation(s)
- Fei Yin
- Department of Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Southern California, Los Angeles, CA, USA
| | - Jia Yao
- Department of Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Southern California, Los Angeles, CA, USA
| | - Harsh Sancheti
- Department of Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Southern California, Los Angeles, CA, USA
| | - Tao Feng
- Department of Preventive Medicine, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | - Roberto C Melcangi
- Department of Pharmacological and Biomolecular Sciences, University of Milan, Milan, Italy
| | - Todd E Morgan
- Davis School of Gerontology, University of Southern California, Los Angeles, CA, USA
| | - Caleb E Finch
- Davis School of Gerontology, University of Southern California, Los Angeles, CA, USA
| | - Christian J Pike
- Davis School of Gerontology, University of Southern California, Los Angeles, CA, USA
| | - Wendy J Mack
- Department of Preventive Medicine, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | - Enrique Cadenas
- Department of Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Southern California, Los Angeles, CA, USA
| | - Roberta D Brinton
- Department of Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Southern California, Los Angeles, CA, USA; Department of Neurology, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA.
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31
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Barron AM, Brown MA, Morgan TE, Pike CJ. Impact of continuous versus discontinuous progesterone on estradiol regulation of neuron viability and sprouting after entorhinal cortex lesion in female rats. Endocrinology 2015; 156:1091-9. [PMID: 25514084 PMCID: PMC4330320 DOI: 10.1210/en.2014-1216] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Because the estrogen-based hormone therapy (HT) in postmenopausal women typically contains a progestogen component, understanding the interactions between estrogens and progestogens is critical for optimizing the potential neural benefits of HT. An important issue in this regard is the use of continuous vs discontinuous hormone treatments. Although sex steroid hormone levels naturally exhibit cyclic fluctuation, many HT formulations include continuous delivery of hormones. Recent findings from our laboratory and others have shown that coadministration of progesterone (P4) can either attenuate or augment beneficial actions of 17β-estradiol (E2) in experimental models depending in part upon the delivery schedule of P4. In this study, we demonstrate that the P4 delivery schedule in combined E2 and P4 treatments alters degenerative and regenerative outcomes of unilateral entorhinal cortex lesion. We assessed how lesion-induced degeneration of layer II neurons in entorhinal cortex layer and deafferentation in dentate gyrus are affected by ovariectomy and treatments with E2 alone or in combination with either continuous or discontinuous P4. Our results demonstrate the combined efficacy of E2 and P4 is dependent on the administration regimen. Importantly, the discontinuous-combined E2+P4 regimen had the greatest neuroprotective efficacy for both end points. These data extend a growing literature that indicates qualitative differences in the neuroprotective effects of E2 as a function of cotreatment with continuous versus discontinuous P4, the understanding of which has important implications for HT in postmenopausal women.
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Affiliation(s)
- Anna M Barron
- Davis School of Gerontology (A.M.B., M.A.B., T.E.M., C.J.P.), University of Southern California, Los Angeles, California 90089; Molecular Imaging Center (A.M.B.), National Institute of Radiological Sciences, Chiba 263-8555, Japan
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32
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Jayaraman A, Lent-Schochet D, Pike CJ. Diet-induced obesity and low testosterone increase neuroinflammation and impair neural function. J Neuroinflammation 2014; 11:162. [PMID: 25224590 PMCID: PMC4190446 DOI: 10.1186/s12974-014-0162-y] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2014] [Accepted: 08/28/2014] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND Low testosterone and obesity are independent risk factors for dysfunction of the nervous system including neurodegenerative disorders such as Alzheimer's disease (AD). In this study, we investigate the independent and cooperative interactions of testosterone and diet-induced obesity on metabolic, inflammatory, and neural health indices in the central and peripheral nervous systems. METHODS Male C57B6/J mice were maintained on normal or high-fat diet under varying testosterone conditions for a four-month treatment period, after which metabolic indices were measured and RNA isolated from cerebral cortex and sciatic nerve. Cortices were used to generate mixed glial cultures, upon which embryonic cerebrocortical neurons were co-cultured for assessment of neuron survival and neurite outgrowth. Peripheral nerve damage was determined using paw-withdrawal assay, myelin sheath protein expression levels, and Na+,K+-ATPase activity levels. RESULTS Our results demonstrate that detrimental effects on both metabolic (blood glucose, insulin sensitivity) and proinflammatory (cytokine expression) responses caused by diet-induced obesity are exacerbated by testosterone depletion. Mixed glial cultures generated from obese mice retain elevated cytokine expression, although low testosterone effects do not persist ex vivo. Primary neurons co-cultured with glial cultures generated from high-fat fed animals exhibit reduced survival and poorer neurite outgrowth. In addition, low testosterone and diet-induced obesity combine to increase inflammation and evidence of nerve damage in the peripheral nervous system. CONCLUSIONS Testosterone and diet-induced obesity independently and cooperatively regulate neuroinflammation in central and peripheral nervous systems, which may contribute to observed impairments in neural health. Together, our findings suggest that low testosterone and obesity are interactive regulators of neuroinflammation that, in combination with adipose-derived inflammatory pathways and other factors, increase the risk of downstream disorders including type 2 diabetes and Alzheimer's disease.
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Affiliation(s)
| | | | - Christian J Pike
- Davis School of Gerontology, University of Southern California, 3715 McClintock Avenue, Los Angeles 90089, CA, USA.
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33
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Barron AM, Christensen AK, Ji B, Suhara T, Higuchi M, Pike CJ. P3‐406: THE ROLE OF STEROID BIOSYNTHESIS IN THE PROTECTIVE ACTIONS OF LIGANDS FOR THE TRANSLOCATOR PROTEIN (TSPO). Alzheimers Dement 2014. [DOI: 10.1016/j.jalz.2014.05.1501] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Affiliation(s)
| | | | - Bin Ji
- National Institute of Radiological SciencesChibaJapan
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34
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Jayaraman A, Christensen A, Moser VA, Vest RS, Miller CP, Hattersley G, Pike CJ. Selective androgen receptor modulator RAD140 is neuroprotective in cultured neurons and kainate-lesioned male rats. Endocrinology 2014; 155:1398-406. [PMID: 24428527 PMCID: PMC3959610 DOI: 10.1210/en.2013-1725] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The decline in testosterone levels in men during normal aging increases risks of dysfunction and disease in androgen-responsive tissues, including brain. The use of testosterone therapy has the potential to increase the risks for developing prostate cancer and or accelerating its progression. To overcome this limitation, novel compounds termed "selective androgen receptor modulators" (SARMs) have been developed that lack significant androgen action in prostate but exert agonist effects in select androgen-responsive tissues. The efficacy of SARMs in brain is largely unknown. In this study, we investigate the SARM RAD140 in cultured rat neurons and male rat brain for its ability to provide neuroprotection, an important neural action of endogenous androgens that is relevant to neural health and resilience to neurodegenerative diseases. In cultured hippocampal neurons, RAD140 was as effective as testosterone in reducing cell death induced by apoptotic insults. Mechanistically, RAD140 neuroprotection was dependent upon MAPK signaling, as evidenced by elevation of ERK phosphorylation and inhibition of protection by the MAPK kinase inhibitor U0126. Importantly, RAD140 was also neuroprotective in vivo using the rat kainate lesion model. In experiments with gonadectomized, adult male rats, RAD140 was shown to exhibit peripheral tissue-specific androgen action that largely spared prostate, neural efficacy as demonstrated by activation of androgenic gene regulation effects, and neuroprotection of hippocampal neurons against cell death caused by systemic administration of the excitotoxin kainate. These novel findings demonstrate initial preclinical efficacy of a SARM in neuroprotective actions relevant to Alzheimer's disease and related neurodegenerative diseases.
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Affiliation(s)
- Anusha Jayaraman
- Davis School of Gerontology (A.J., A.C., R.S.V., C.J.P.) and Neuroscience Graduate Program (V.A.M., C.J.P.), University of Southern California, Los Angeles, California 90089; and Radius Health, Inc. (C.P.M., G.H.), Cambridge, Massachusetts 02139
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35
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Abstract
Obesity, metabolic syndrome, and type 2 diabetes (T2D) are related disorders with widespread deleterious effects throughout the body. One important target of damage is the brain. Persons with metabolic disorders are at significantly increased risk for cognitive decline and the development of vascular dementia and Alzheimer's disease. Our review of available evidence from epidemiologic, clinical, and basic research suggests that neural dysfunction from T2D-related disease results from several underlying mechanisms, including metabolic, inflammatory, vascular, and oxidative changes. The relationships between T2D and neural dysfunction are regulated by several modifiers. We emphasize 2 such modifiers, the genetic risk factor apolipoprotein E and an age-related endocrine change, low testosterone. Both factors are independent risk factors for Alzheimer's disease that may also cooperatively regulate pathologic interactions between T2D and dementia. Continued elucidation of the links between metabolic disorders and neural dysfunction promises to foster the development of effective therapeutic strategies.
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Affiliation(s)
- Anusha Jayaraman
- 3715 McClintock Avenue, Davis School of Gerontology, University of Southern California, Los Angeles, CA 90089-0191 USA, , (213) 740-8244
| | - Christian J. Pike
- 3715 McClintock Avenue, Davis School of Gerontology, University of Southern California, Los Angeles, CA 90089-0191 USA, , (213) 740-4205
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36
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Jayaraman A, Pike CJ. Differential effects of synthetic progestagens on neuron survival and estrogen neuroprotection in cultured neurons. Mol Cell Endocrinol 2014; 384:52-60. [PMID: 24424444 PMCID: PMC3954450 DOI: 10.1016/j.mce.2014.01.003] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/23/2013] [Revised: 11/22/2013] [Accepted: 01/03/2014] [Indexed: 11/19/2022]
Abstract
Progesterone and other progestagens are used in combination with estrogens for clinical purposes, including contraception and postmenopausal hormone therapy. Progesterone and estrogens have interactive effects in brain, however interactions between synthetic progestagens and 17β-estradiol (E2) in neurons are not well understood. In this study, we investigated the effects of seven clinically relevant progestagens on estrogen receptor (ER) mRNA expression, E2-induced neuroprotection, and E2-induced BDNF mRNA expression. We found that medroxyprogesterone acetate decreased both ERα and ERβ expression and blocked E2-mediated neuroprotection and BDNF expression. Conversely, levonorgestrel and nesterone increased ERα and or ERβ expression, were neuroprotective, and failed to attenuate E2-mediated increases in neuron survival and BDNF expression. Other progestagens tested, including norethindrone, norethindrone acetate, norethynodrel, and norgestimate, had variable effects on the measured endpoints. Our results demonstrate a range of qualitatively different actions of progestagens in cultured neurons, suggesting significant variability in the neural effects of clinically utilized progestagens.
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Affiliation(s)
- Anusha Jayaraman
- Davis School of Gerontology, University of Southern California, Los Angeles, CA 90089, USA
| | - Christian J Pike
- Davis School of Gerontology, University of Southern California, Los Angeles, CA 90089, USA.
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37
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Barron AM, Rosario ER, Elteriefi R, Pike CJ. Sex-specific effects of high fat diet on indices of metabolic syndrome in 3xTg-AD mice: implications for Alzheimer's disease. PLoS One 2013; 8:e78554. [PMID: 24205258 PMCID: PMC3810257 DOI: 10.1371/journal.pone.0078554] [Citation(s) in RCA: 87] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2012] [Accepted: 09/20/2013] [Indexed: 01/31/2023] Open
Abstract
Multiple factors of metabolic syndrome have been implicated in the pathogenesis of Alzheimer's disease (AD), including abdominal obesity, insulin resistance, endocrine dysfunction and dyslipidemia. High fat diet, a common experimental model of obesity and metabolic syndrome, has been shown to accelerate cognitive decline and AD-related neuropathology in animal models. However, sex interacts with the metabolic outcomes of high fat diet and, therefore, may alter neuropathological consequences of dietary manipulations. This study examines the effects of sex and high fat diet on metabolic and AD-related neuropathological outcomes in 3xTg-AD mice. Three month-old male and female 3xTg-AD mice were fed either standard or high fat diets for 4 months. Obesity was observed in all high fat fed mice; however, ectopic fat accumulation, hyperglycemia and hyperinsulinemia were observed only in males. Interestingly, despite the different metabolic outcomes of high fat diet, the neuropathological consequences were similar: both male and female mice maintained under high fat diet exhibited significant worsening in behavioral performance and hippocampal accumulation of β-amyloid protein. Because high fat diet resulted in obesity and increased AD-like pathology in both sexes, these data support a role of obesity-related factors in promoting AD pathogenesis.
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Affiliation(s)
- Anna M. Barron
- Davis School of Gerontology, University of Southern California, Los Angeles, California, United States of America
| | - Emily R. Rosario
- Davis School of Gerontology, University of Southern California, Los Angeles, California, United States of America
| | - Reem Elteriefi
- Davis School of Gerontology, University of Southern California, Los Angeles, California, United States of America
| | - Christian J. Pike
- Davis School of Gerontology, University of Southern California, Los Angeles, California, United States of America
- * E-mail:
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38
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Abstract
Age-related loss of sex steroid hormones is a established risk factor for the development of Alzheimer's disease (AD) in women and men. While the relationships between the sex steroid hormones and AD are not fully understood, findings from both human and experimental paradigms indicate that depletion of estrogens in women and androgens in men increases vulnerability of the aging brain to AD pathogenesis. We review evidence of a wide range of beneficial neural actions of sex steroid hormones that may contribute to their hypothesized protective roles against AD. Both estrogens and androgens exert general neuroprotective actions relevant to a several neurodegenerative conditions, some in a sex-specific manner, including protection from neuron death and promotion of select aspects of neural plasticity. In addition, estrogens and androgens regulate key processes implicated in AD pathogenesis, in particular the accumulation of β-amyloid protein. We discuss evidence of hormone-specific mechanisms related to the regulation of the production and clearance of β-amyloid as critical protective pathways. Continued elucidation of these pathways promises to yield effective hormone-based strategies to delay development of AD.
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Affiliation(s)
- Rebekah S Vest
- USC Davis School of Gerontology, University of Southern California, Los Angeles, CA 90089, USA
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39
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Caruso D, Barron AM, Brown MA, Abbiati F, Carrero P, Pike CJ, Garcia-Segura LM, Melcangi RC. Age-related changes in neuroactive steroid levels in 3xTg-AD mice. Neurobiol Aging 2012; 34:1080-9. [PMID: 23122920 DOI: 10.1016/j.neurobiolaging.2012.10.007] [Citation(s) in RCA: 83] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2012] [Revised: 10/02/2012] [Accepted: 10/07/2012] [Indexed: 11/19/2022]
Abstract
Although neuroactive steroids exert neuroprotective actions in different experimental models of neurodegenerative diseases, including those of Alzheimer's disease (AD), their relationships with aged related physiologic and pathologic brain changes remain to be clarified. In this study the levels of pregnenolone, dehydroepiandrosterone, progesterone, dihydroprogesterone, tetrahydroprogesterone, isopregnanolone, testosterone, dihydrotestosterone, 5α-androstane-3α,17β-diol, 5α-androstane-3β,17β-diol, 17α-estradiol, and 17β-estradiol were assessed in the limbic region of young adult (7 months) and aged (24 months) male wild type and triple transgenic AD mice. Age related neuropathological changes in AD brains, such as β-amyloid accumulation and gliosis, were associated with modified levels of specific neuroactive steroids and particularly with changes in the levels of progesterone and testosterone metabolites. The altered levels of neuroactive steroids in aged AD brains might impact on the activation of neuroprotective signaling mediated by classic and nonclassic steroid receptors, like the gamma-aminobuttyric acid (GABA)-A receptor.
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Affiliation(s)
- Donatella Caruso
- Department of Pharmacological and Biomolecular Sciences, Center of Excellence on Neurodegenerative Diseases, Università degli Studi di Milano, Milano, Italy
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40
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Jayaraman A, Carroll JC, Morgan TE, Lin S, Zhao L, Arimoto JM, Murphy MP, Beckett TL, Finch CE, Brinton RD, Pike CJ. 17β-estradiol and progesterone regulate expression of β-amyloid clearance factors in primary neuron cultures and female rat brain. Endocrinology 2012; 153:5467-79. [PMID: 22962256 PMCID: PMC3473201 DOI: 10.1210/en.2012-1464] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/24/2012] [Accepted: 08/06/2012] [Indexed: 02/04/2023]
Abstract
The accumulation of β-amyloid protein (Aβ) is a key risk factor in the development of Alzheimer's disease. The ovarian sex steroid hormones 17β-estradiol (E(2)) and progesterone (P(4)) have been shown to regulate Aβ accumulation, although the underlying mechanism(s) remain to be fully elucidated. In this study, we investigate the effects of E(2) and P(4) treatment on the expression levels of Aβ clearance factors including insulin-degrading enzyme, neprilysin, endothelin-converting enzyme 1 and 2, angiotensin-converting enzyme, and transthyretin, both in primary neuron cultures and female rat brains. Our results show that E(2) and P(4) affect the expression levels of several Aβ clearance factors in dose- and time-dependent manners. Most notably, expression of insulin-degrading enzyme is significantly increased by both hormones in cultured neurons and in vivo and is inversely associated with the soluble Aβ levels in vivo. These findings further define sex steroid hormone actions involved in regulation of Aβ, a relationship potentially important to therapeutic approaches aimed at reducing risk of Alzheimer's disease.
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Affiliation(s)
- Anusha Jayaraman
- Neuroscience Graduate Program, University of Southern California, Los Angeles, California 90089, USA
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41
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Rosario ER, Carroll JC, Pike CJ. Evaluation of the effects of testosterone and luteinizing hormone on regulation of β-amyloid in male 3xTg-AD mice. Brain Res 2012; 1466:137-45. [PMID: 22587890 DOI: 10.1016/j.brainres.2012.05.011] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2012] [Revised: 04/12/2012] [Accepted: 05/05/2012] [Indexed: 01/15/2023]
Abstract
During normal aging, men experience a significant decline in testosterone levels and a compensatory elevation in levels of gonadotropin luteinizing hormone (LH). Both low testosterone and elevated LH have been identified as significant risk factors for the development of Alzheimer's disease (AD) in men. It is unclear whether changes in testosterone or LH primarily underlie the relationship with AD, and therefore may be a more suitable therapeutic target. To examine this issue, we compared levels of β-amyloid (Aβ) immunoreactivity in male 3xTg-AD mice under varying experimental conditions associated with relatively low or high levels of testosterone and/or LH. In gonadally intact mice, Aβ accumulation increased after treatment with the gonadotropin-releasing hormone agonist leuprolide, which inhibits the hypothalamic-pituitary-gonadal (HPG) axis and reduces both testosterone and LH levels. In gonadectomized (GDX) mice with low testosterone and high LH, we also observed increased Aβ levels. Treatment of GDX mice with testosterone significantly reduced Aβ levels. In contrast, leuprolide did not significantly decrease Aβ levels and moreover, inhibited the Aβ-lowering effect of testosterone. Evaluation of hippocampal-dependent behavior revealed parallel findings, with performance in GDX mice improved by testosterone but not leuprolide. These data suggest that Aβ-lowering actions of testosterone are mediated directly by androgen pathways rather than indirectly via regulation of LH and the HPG axis. These findings support the clinical evaluation of androgen therapy in the prevention and perhaps treatment of AD in hypogonadal men.
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Affiliation(s)
- Emily R Rosario
- USC Davis School of Gerontology, University of Southern California, Los Angeles, CA 90089, USA.
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42
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Ling D, Pike CJ, Salvaterra PM. Deconvolution of the confounding variations for reverse transcription quantitative real-time polymerase chain reaction by separate analysis of biological replicate data. Anal Biochem 2012; 427:21-5. [PMID: 22561916 DOI: 10.1016/j.ab.2012.04.029] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2012] [Revised: 04/25/2012] [Accepted: 04/26/2012] [Indexed: 10/28/2022]
Abstract
Reverse transcription quantitative real-time polymerase chain reaction (RT-qPCR) uses threshold cycles (Ct values) for measuring relative gene expression. Ct values are signal-to-noise data composed of target gene expression and multiple sources of confounding variations. Data analysis is to minimize technical noises, evaluate biological variances, and estimate treatment-attributable expression changes of particular genes. However, this function is not sufficiently fulfilled in current analytic methods. An important but unrecognizable problem is that Ct values from all biological replicates and technical repeats are pooled across genes and treatment types. This violates the sample-specific association between target and reference genes, leading to inefficient removal of technical noises. To resolve this problem, here we propose to separate Ct values into replicate-specific data subsets and iteratively analyze expression ratios for individual data subsets. The individual expression ratios, rather than the raw Ct values, are pooled to determine the final expression change. The variances of all biological replicates and technical repeats across all target and reference genes are summed up. Our results from example data demonstrate that this separated method can substantially minimize RT-qPCR variance compared with the traditional methods using pooled Ct profiles. This analytic strategy is more effective in control of technical noises and improves the fidelity of RT-qPCR quantification.
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Affiliation(s)
- Daijun Ling
- Department of Neuroscience, Beckman Research Institute of City of Hope, Duarte, CA 91010, USA.
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43
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Abstract
Caspases, a family of cysteine proteases, are widely activated in neurons and glia in the injured brain, a response thought to induce apoptosis. However, caspase activation in astrocytes following injury is not strongly associated with apoptosis. The present study investigates the potential role of caspase activation in astrocytes with another characteristic response to neural injury, astrogliosis. Caspase activity and morphological and biochemical indices of astrogliosis and apoptosis were assessed in (i) cultured neonatal rat astrocytes treated with astrogliosis-inducing stimuli (dibutryl cAMP, β-amyloid peptide), and (ii) cultures of adult rat hippocampal astrocytes generated from control and kainate-lesioned rats. The effects of broad spectrum and specific pharmacological caspase inhibitors were assessed on indicators of astrogliosis, including stellate morphology and expression of glutamine synthetase and fibroblast growth factor-2. Reactive neonatal and adult astrocytes demonstrated an increase in total caspase activity with a corresponding increase in the expression of active caspase-3 in the absence of cell death. Broad spectrum caspase inhibition with zVAD significantly attenuated increases in glutamine synthetase and fibroblast growth factor-2 in the reactive astrocytes. In the reactive neonatal astrocyte cultures, specific inhibition of caspases-3 and -11 also attenuated glutamine synthetase and fibroblast growth factor-2 expression, but did not reverse the morphological reactive phenotype. Astrogliosis is observed in all forms of brain injury and despite extensive study, its molecular triggers remain largely unknown. While previous studies have demonstrated active caspases in astrocytes following acute brain injury, here we present evidence functionally implicating the caspases in astrogliosis.
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Affiliation(s)
- Radha Aras
- Davis School of Gerontology, University of Southern California, Los Angeles, CA 90089
- Neuroscience Graduate Program, University of Southern California, Los Angeles, CA 90089
| | - Anna M. Barron
- Davis School of Gerontology, University of Southern California, Los Angeles, CA 90089
| | - Christian J. Pike
- Davis School of Gerontology, University of Southern California, Los Angeles, CA 90089
- Neuroscience Graduate Program, University of Southern California, Los Angeles, CA 90089
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44
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Zhao L, Morgan TE, Mao Z, Lin S, Cadenas E, Finch CE, Pike CJ, Mack WJ, Brinton RD. Continuous versus cyclic progesterone exposure differentially regulates hippocampal gene expression and functional profiles. PLoS One 2012; 7:e31267. [PMID: 22393359 PMCID: PMC3290616 DOI: 10.1371/journal.pone.0031267] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2011] [Accepted: 01/05/2012] [Indexed: 12/27/2022] Open
Abstract
This study investigated the impact of chronic exposure to continuous (CoP4) versus cyclic progesterone (CyP4) alone or in combination with 17β-estradiol (E2) on gene expression profiles targeting bioenergetics, metabolism and inflammation in the adult female rat hippocampus. High-throughput qRT-PCR analyses revealed that ovarian hormonal depletion induced by ovariectomy (OVX) led to multiple significant gene expression alterations, which were to a great extent reversed by co-administration of E2 and CyP4. In contrast, co-administration of E2 and CoP4 induced a pattern highly resembling OVX. Bioinformatics analyses further revealed clear disparities in functional profiles associated with E2+CoP4 and E2+CyP4. Genes involved in mitochondrial energy (ATP synthase α subunit; Atp5a1), redox homeostasis (peroxiredoxin 5; Prdx5), insulin signaling (insulin-like growth factor I; Igf1), and cholesterol trafficking (liver X receptor α subtype; Nr1h3), differed in direction of regulation by E2+CoP4 (down-regulation relative to OVX) and E2+CyP4 (up-regulation relative to OVX). In contrast, genes involved in amyloid metabolism (β-secretase; Bace1) differed only in degree of regulation, as both E2+CoP4 and E2+CyP4 induced down-regulation at different efficacy. E2+CyP4-induced changes could be associated with regulation of progesterone receptor membrane component 1(Pgrmc1). In summary, results from this study provide evidence at the molecular level that differing regimens of hormone therapy (HT) can induce disparate gene expression profiles in brain. From a translational perspective, confirmation of these results in a model of natural menopause, would imply that the common regimen of continuous combined HT may have adverse consequences whereas a cyclic combined regimen, which is more physiological, could be an effective strategy to maintain neurological health and function throughout menopausal aging.
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Affiliation(s)
- Liqin Zhao
- Department of Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Southern California, Los Angeles, California, United States of America
- * E-mail: (LZ); (RDB)
| | - Todd E. Morgan
- Davis School of Gerontology, University of Southern California, Los Angeles, California, United States of America
| | - Zisu Mao
- Department of Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Southern California, Los Angeles, California, United States of America
| | - Sharon Lin
- Davis School of Gerontology, University of Southern California, Los Angeles, California, United States of America
| | - Enrique Cadenas
- Department of Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Southern California, Los Angeles, California, United States of America
| | - Caleb E. Finch
- Davis School of Gerontology, University of Southern California, Los Angeles, California, United States of America
| | - Christian J. Pike
- Davis School of Gerontology, University of Southern California, Los Angeles, California, United States of America
| | - Wendy J. Mack
- Department of Preventive Medicine, Keck School of Medicine, University of Southern California, Los Angeles, California, United States of America
| | - Roberta D. Brinton
- Department of Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Southern California, Los Angeles, California, United States of America
- Department of Neurology, Keck School of Medicine, University of Southern California, Los Angeles, California, United States of America
- * E-mail: (LZ); (RDB)
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45
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Abstract
A promising strategy to delay and perhaps prevent Alzheimer's disease (AD) is to identify the age-related changes that put the brain at risk for the disease. A significant normal age change known to result in tissue-specific dysfunction is the depletion of sex hormones. In women, menopause results in a relatively rapid loss of estradiol and progesterone. In men, aging is associated with a comparatively gradual yet significant decrease in testosterone. We review a broad literature that indicates age-related losses of estrogens in women and testosterone in men are risk factors for AD. Both estrogens and androgens exert a wide range of protective actions that improve multiple aspects of neural health, suggesting that hormone therapies have the potential to combat AD pathogenesis. However, translation of experimental findings into effective therapies has proven challenging. One emerging treatment option is the development of novel hormone mimetics termed selective estrogen and androgen receptor modulators. Continued research of sex hormones and their roles in the aging brain is expected to yield valuable approaches to reducing the risk of AD.
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Affiliation(s)
- Anna M. Barron
- USC Davis School of Gerontology, University of Southern California, Los Angeles, CA 90089 USA
- Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, 153-8902 Japan
| | - Christian J. Pike
- USC Davis School of Gerontology, University of Southern California, Los Angeles, CA 90089 USA
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46
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Abstract
A promising strategy to delay and perhaps prevent Alzheimer's disease (AD) is to identify the age-related changes that put the brain at risk for the disease. A significant normal age change known to result in tissue-specific dysfunction is the depletion of sex hormones. In women, menopause results in a relatively rapid loss of estradiol and progesterone. In men, aging is associated with a comparatively gradual yet significant decrease in testosterone. We review a broad literature that indicates age-related losses of estrogens in women and testosterone in men are risk factors for AD. Both estrogens and androgens exert a wide range of protective actions that improve multiple aspects of neural health, suggesting that hormone therapies have the potential to combat AD pathogenesis. However, translation of experimental findings into effective therapies has proven challenging. One emerging treatment option is the development of novel hormone mimetics termed selective estrogen and androgen receptor modulators. Continued research of sex hormones and their roles in the aging brain is expected to yield valuable approaches to reducing the risk of AD.
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Affiliation(s)
- Anna M Barron
- USC Davis School of Gerontology, University of Southern California, Los Angeles, CA 90089 USA
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47
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Rosario ER, Chang L, Head EH, Stanczyk FZ, Pike CJ. Brain levels of sex steroid hormones in men and women during normal aging and in Alzheimer's disease. Neurobiol Aging 2011; 32:604-13. [PMID: 19428144 PMCID: PMC2930132 DOI: 10.1016/j.neurobiolaging.2009.04.008] [Citation(s) in RCA: 192] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2008] [Revised: 03/21/2009] [Accepted: 04/10/2009] [Indexed: 01/12/2023]
Abstract
We examined the relationships between normal aging, Alzheimer's disease (AD), and brain levels of sex steroid hormones in men and women. In postmortem brain tissue from neuropathologically normal, postmenopausal women, we found no age-related changes in brain levels of either androgens or estrogens. In comparing women with and without AD at different ages, brain levels of estrogens and androgens were lower in AD cases aged 80 years and older but not significantly different in the 60-79 year age range. In male brains, we observed that normal aging was associated with significant decreases in androgens but not estrogens. Further, in men aged 60-79 years, brain levels of testosterone but not estrogens were lower in cases with mild neuropathological changes as well as those with advanced AD neuropathology. In male cases over age 80, brain levels hormones did not significantly vary by neuropathological status. To begin investigating the relationships between hormone levels and indices of AD neuropathology, we measured brain levels of soluble β-amyloid (Aβ). In male cases with mild neuropathological changes, we found an inverse relationship between brain levels of testosterone and soluble Aβ. Collectively, these findings demonstrate sex-specific relationships between normal, age-related depletion of androgens and estrogens in men and women, which may be relevant to development of AD.
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Affiliation(s)
- Emily R. Rosario
- Davis School of Gerontology, University of Southern California, Los Angeles, CA 90089
| | - Lilly Chang
- Department of Obstetrics and Gynecology, Keck School of Medicine, University of Southern California, Los Angeles, CA 90089
| | - Elizabeth H. Head
- Department of Neurology, University of California Irvine, Irvine, CA 92697
| | - Frank Z. Stanczyk
- Department of Obstetrics and Gynecology, Keck School of Medicine, University of Southern California, Los Angeles, CA 90089
| | - Christian J. Pike
- Davis School of Gerontology, University of Southern California, Los Angeles, CA 90089
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48
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Carroll JC, Rosario ER, Kreimer S, Villamagna A, Gentzschein E, Stanczyk FZ, Pike CJ. Sex differences in β-amyloid accumulation in 3xTg-AD mice: role of neonatal sex steroid hormone exposure. Brain Res 2010; 1366:233-45. [PMID: 20934413 DOI: 10.1016/j.brainres.2010.10.009] [Citation(s) in RCA: 195] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2010] [Revised: 10/01/2010] [Accepted: 10/01/2010] [Indexed: 11/16/2022]
Abstract
The risk of Alzheimer's disease (AD) is higher in women than in men, a sex difference that likely results from the effects of sex steroid hormones. To investigate this relationship, we first compared progression of β-amyloid (Aβ) pathology in male and female triple transgenic (3xTg-AD) mice. We found that female 3xTg-AD mice exhibit significantly greater Aβ burden and larger behavioral deficits than age-matched males. Next, we evaluated how the organizational effects of sex steroid hormones during postnatal development may affect adult vulnerability to Aβ pathology. We observed that male 3xTg-AD mice demasculinized during early development exhibit significantly increased Aβ accumulation in adulthood. In contrast, female mice defeminized during early development exhibit a more male-like pattern of Aβ pathology in adulthood. Taken together, these results demonstrate significant sex differences in pathology in 3xTg-AD mice and suggest that these differences may be mediated by organizational actions of sex steroid hormones during development.
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Affiliation(s)
- Jenna C Carroll
- Neuroscience Graduate Program, University of Southern California, Los Angeles, CA 90089, USA
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49
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Abstract
Androgens can protect neurones from injury, although androgen neuroprotection is not well characterised in terms of either specificity or mechanism. In the present study, we compared the ability of androgens to protect neurones against a panel of insults, empirically determined to induce cell death by apoptotic or non-apoptotic mechanisms. Three criteria defining but not inclusive of apoptosis are: protection by caspase inhibition, protection by protein synthesis inhibition and the presence of pyknotic nuclei. According to these criteria, beta-amyloid, staurosporine, and Apoptosis Activator II induced cell death involving apoptosis, whereas hydrogen peroxide (H(2)O(2)), iron, calcium ionophore and 3-nitropropionic acid induced cell death featuring non-apoptotic characteristics. Pretreatment of hippocampal neurones with testosterone or dihydrotestosterone attenuated cell death induced by beta-amyloid, staurosporine and Apoptosis Activator II, but none of the other insults. The anti-oxidant Trolox did not reduce cell death induced by beta-amyloid, staurosporine and Apoptosis Activator II, but did protect against H(2)O(2) and iron. Similarly, a supra-physiological concentration of oestrogen reduced cell death induced by H(2)O(2) and iron, an effect not observed with androgens. We also show that activation of oestrogen pathways was not necessary for androgen neuroprotection. These data suggest that androgens directly activate a neuroprotective mechanism specific to inhibition of cell death involving apoptosis. Determining the specificity of androgen neuroprotection may enable the development of androgen compounds for the treatment of neurodegenerative disorders.
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Affiliation(s)
- T V Nguyen
- Neuroscience Graduate Programme and Davis School of Gerontology, University of Southern California, Los Angeles, CA 90089-0191, USA
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50
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Rosario ER, Carroll J, Pike CJ. Testosterone regulation of Alzheimer-like neuropathology in male 3xTg-AD mice involves both estrogen and androgen pathways. Brain Res 2010; 1359:281-90. [PMID: 20807511 DOI: 10.1016/j.brainres.2010.08.068] [Citation(s) in RCA: 90] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2010] [Revised: 08/20/2010] [Accepted: 08/22/2010] [Indexed: 01/20/2023]
Abstract
Normal, age-related depletion of the androgen testosterone is a risk factor for Alzheimer's disease (AD) in men. Previously, we reported that experimental androgen depletion significantly accelerates development of AD-like neuropathology in the 3xTg-AD triple-transgenic mouse model of AD, an effect prevented by androgen treatment. Because testosterone is metabolized in brain into both the androgen dihydrotestosterone (DHT) and the estrogen 17β-estradiol (E2), testosterone can mediate its effects through androgen and or estrogen pathways. To define the role of androgen and estrogen pathways in regulation of AD-like neuropathology, we compared the effects of testosterone (T) and its metabolites DHT and E2 in male 3xTg-AD mice depleted of endogenous sex steroid hormones by gonadectomy (GDX). Male 3xTg-AD mice were sham GDX or GDX, immediately treated with vehicle, T, DHT, or E2, and 4 months later evaluated for two indices of AD-like neuropathology, β-amyloid (Aβ) accumulation and tau hyperphosphorylation. In comparison to sham GDX mice, we observed a significant increase in Aβ accumulation in GDX mice in subiculum, hippocampus, and amygdala. Treatment of GDX mice with T prevented the increased Aβ accumulation in all three brain regions. DHT treatment yielded similar results, significantly reducing Aβ accumulation across brain regions. Interestingly, E2 prevented Aβ accumulation in hippocampus but exerted only partial effects in subiculum and amygdala. Levels of tau hyperphosphorylation in sham GDX male 3xTg-AD mice were modest and only slightly increased by GDX. Treatment of GDX mice with T or E2 but not DHT reduced tau hyperphosphorylation to levels lower than observed in sham animals. These data suggest that testosterone regulates Aβ pathology through androgen and estrogen pathways and reduces tau pathology largely through estrogen pathways. These findings further define hormone pathways involved in regulation of AD-related pathology, information that is important for understanding disease etiology and developing pathway-specific hormone interventions.
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Affiliation(s)
- Emily R Rosario
- Neuroscience Graduate Program, Davis School of Gerontology, University of Southern California, Los Angeles, CA 90089, USA
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