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Reed EG, Keller-Norrell PR. Minding the Gap: Exploring Neuroinflammatory and Microglial Sex Differences in Alzheimer's Disease. Int J Mol Sci 2023; 24:17377. [PMID: 38139206 PMCID: PMC10743742 DOI: 10.3390/ijms242417377] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2023] [Revised: 12/04/2023] [Accepted: 12/09/2023] [Indexed: 12/24/2023] Open
Abstract
Research into Alzheimer's Disease (AD) describes a link between AD and the resident immune cells of the brain, the microglia. Further, this suspected link is thought to have underlying sex effects, although the mechanisms of these effects are only just beginning to be understood. Many of these insights are the result of policies put in place by funding agencies such as the National Institutes of Health (NIH) to consider sex as a biological variable (SABV) and the move towards precision medicine due to continued lackluster therapeutic options. The purpose of this review is to provide an updated assessment of the current research that summarizes sex differences and the research pertaining to microglia and their varied responses in AD.
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Affiliation(s)
- Erin G. Reed
- Department of Pharmaceutical Sciences, Northeast Ohio Medical University, Rootstown, OH 44242, USA
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Palmer JM, Huentelman M, Ryan L. More than just risk for Alzheimer's disease: APOE ε4's impact on the aging brain. Trends Neurosci 2023; 46:750-763. [PMID: 37460334 DOI: 10.1016/j.tins.2023.06.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2023] [Revised: 05/16/2023] [Accepted: 06/12/2023] [Indexed: 08/18/2023]
Abstract
The apolipoprotein ε4 (APOE ε4) allele is most commonly associated with increased risk for late-onset Alzheimer's disease (AD). However, recent longitudinal studies suggest that these risks are overestimated; most ε4 carriers will not develop dementia in their lifetime. In this article, we review new evidence regarding the impact of APOE ε4 on cognition among healthy older adults. We discuss emerging work from animal models suggesting that ε4 impacts brain structure and function in multiple ways that may lead to age-related cognitive impairment, independent from AD pathology. We discuss the importance of taking an individualized approach in future studies by incorporating biomarkers and neuroimaging methods that may better disentangle the phenotypic influences of APOE ε4 on the aging brain from prodromal AD pathology.
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Affiliation(s)
- Justin M Palmer
- The University of Arizona, Tucson, AZ, USA; Arizona Alzheimer's Consortium, Phoenix, AZ, USA.
| | - Matthew Huentelman
- Translational Genomics Research Institute, Phoenix, AZ, USA; Arizona Alzheimer's Consortium, Phoenix, AZ, USA
| | - Lee Ryan
- The University of Arizona, Tucson, AZ, USA; Arizona Alzheimer's Consortium, Phoenix, AZ, USA.
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Nguyen V, Thomas P, Pemberton S, Babin A, Noonan C, Weaver R, Banks WA, Rhea EM. Central nervous system insulin signaling can influence the rate of insulin influx into brain. Fluids Barriers CNS 2023; 20:28. [PMID: 37076875 PMCID: PMC10114367 DOI: 10.1186/s12987-023-00431-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2022] [Accepted: 04/10/2023] [Indexed: 04/21/2023] Open
Abstract
BACKGROUND Insulin transport across the blood-brain barrier (BBB) is a highly regulated, saturable process, known to be affected by many peripheral substrates including insulin itself and triglycerides. This is in contrast to insulin leakage into peripheral tissues. Whether the central nervous system (CNS) can control the rate of insulin uptake by brain remains to be determined. Insulin BBB interactions are impaired in Alzheimer's disease (AD) and CNS insulin resistance is widely prevalent in AD. Therefore, if CNS insulin controls the rate of insulin transport across the BBB, then the defective transport of insulin seen in AD could be one manifestation of the resistance to CNS insulin observed in AD. METHODS We investigated whether enhancing CNS insulin levels or induction of CNS insulin resistance using an inhibitor of the insulin receptor altered the blood-to-brain transport of radioactively labeled insulin in young, healthy mice. RESULTS We found that insulin injected directly into the brain decreased insulin transport across the BBB for whole brain and the olfactory bulb in male mice, whereas insulin receptor blockade decreased transport in female mice for whole brain and hypothalamus. Intranasal insulin, currently being investigated as a treatment in AD patients, decreased transport across the BBB of the hypothalamus. CONCLUSIONS These results suggest CNS insulin can control the rate of insulin brain uptake, connecting CNS insulin resistance to the rate of insulin transport across the BBB.
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Affiliation(s)
- Van Nguyen
- School of Medicine, University of Washington, Seattle, WA, 98195, USA
| | - Peter Thomas
- Geriatric Research Education and Clinical Center, Veterans Affairs Puget Sound Health Care System, Seattle, WA, 98108, USA
| | - Sarah Pemberton
- Geriatric Research Education and Clinical Center, Veterans Affairs Puget Sound Health Care System, Seattle, WA, 98108, USA
- University of Washington, Seattle, WA, 98195, USA
| | - Alice Babin
- Geriatric Research Education and Clinical Center, Veterans Affairs Puget Sound Health Care System, Seattle, WA, 98108, USA
| | - Cassidy Noonan
- Geriatric Research Education and Clinical Center, Veterans Affairs Puget Sound Health Care System, Seattle, WA, 98108, USA
- University of Washington, Seattle, WA, 98195, USA
| | - Riley Weaver
- Geriatric Research Education and Clinical Center, Veterans Affairs Puget Sound Health Care System, Seattle, WA, 98108, USA
| | - William A Banks
- Geriatric Research Education and Clinical Center, Veterans Affairs Puget Sound Health Care System, Seattle, WA, 98108, USA
- Department of Medicine, Division of Gerontology and Geriatric Medicine, University of Washington, Seattle, WA, 98195, USA
| | - Elizabeth M Rhea
- Geriatric Research Education and Clinical Center, Veterans Affairs Puget Sound Health Care System, Seattle, WA, 98108, USA.
- Department of Medicine, Division of Gerontology and Geriatric Medicine, University of Washington, Seattle, WA, 98195, USA.
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Adesse D, Gladulich L, Alvarez-Rosa L, Siqueira M, Marcos AC, Heider M, Motta CS, Torices S, Toborek M, Stipursky J. Role of aging in Blood-Brain Barrier dysfunction and susceptibility to SARS-CoV-2 infection: impacts on neurological symptoms of COVID-19. Fluids Barriers CNS 2022; 19:63. [PMID: 35982454 PMCID: PMC9386676 DOI: 10.1186/s12987-022-00357-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2022] [Accepted: 07/18/2022] [Indexed: 12/21/2022] Open
Abstract
COVID-19, which is caused by Severe Acute Respiratory Syndrome Corona Virus 2 (SARS-CoV-2), has resulted in devastating morbidity and mortality worldwide due to lethal pneumonia and respiratory distress. In addition, the central nervous system (CNS) is well documented to be a target of SARS-CoV-2, and studies detected SARS-CoV-2 in the brain and the cerebrospinal fluid of COVID-19 patients. The blood-brain barrier (BBB) was suggested to be the major route of SARS-CoV-2 infection of the brain. Functionally, the BBB is created by an interactome between endothelial cells, pericytes, astrocytes, microglia, and neurons, which form the neurovascular units (NVU). However, at present, the interactions of SARS-CoV-2 with the NVU and the outcomes of this process are largely unknown. Moreover, age was described as one of the most prominent risk factors for hospitalization and deaths, along with other comorbidities such as diabetes and co-infections. This review will discuss the impact of SARS-CoV-2 on the NVU, the expression profile of SARS-CoV-2 receptors in the different cell types of the CNS and the possible role of aging in the neurological outcomes of COVID-19. A special emphasis will be placed on mitochondrial functions because dysfunctional mitochondria are also a strong inducer of inflammatory reactions and the "cytokine storm" associated with SARS-CoV-2 infection. Finally, we will discuss possible drug therapies to treat neural endothelial function in aged patients, and, thus, alleviate the neurological symptoms associated with COVID-19.
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Affiliation(s)
- Daniel Adesse
- Laboratório de Biologia Estrutural, Instituto Oswaldo Cruz, Fiocruz, Avenida Brasil, 4365, Pavilhão Carlos Chagas, sala 307b, Rio de Janeiro, RJ, 21040-360, Brazil.
- Department of Biochemistry and Molecular Biology, University of Miami Miller School of Medicine, Miami, FL, 33136, USA.
| | - Luis Gladulich
- Laboratório de Biologia Estrutural, Instituto Oswaldo Cruz, Fiocruz, Avenida Brasil, 4365, Pavilhão Carlos Chagas, sala 307b, Rio de Janeiro, RJ, 21040-360, Brazil
| | - Liandra Alvarez-Rosa
- Laboratório de Biologia Estrutural, Instituto Oswaldo Cruz, Fiocruz, Avenida Brasil, 4365, Pavilhão Carlos Chagas, sala 307b, Rio de Janeiro, RJ, 21040-360, Brazil
- Laboratório Compartilhado, Instituto de Ciências Biomédicas, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Michele Siqueira
- Laboratório Compartilhado, Instituto de Ciências Biomédicas, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Anne Caroline Marcos
- Laboratório de Biologia Estrutural, Instituto Oswaldo Cruz, Fiocruz, Avenida Brasil, 4365, Pavilhão Carlos Chagas, sala 307b, Rio de Janeiro, RJ, 21040-360, Brazil
| | - Marialice Heider
- Laboratório de Biologia Estrutural, Instituto Oswaldo Cruz, Fiocruz, Avenida Brasil, 4365, Pavilhão Carlos Chagas, sala 307b, Rio de Janeiro, RJ, 21040-360, Brazil
| | - Caroline Soares Motta
- Laboratório de Biologia Estrutural, Instituto Oswaldo Cruz, Fiocruz, Avenida Brasil, 4365, Pavilhão Carlos Chagas, sala 307b, Rio de Janeiro, RJ, 21040-360, Brazil
| | - Silvia Torices
- Department of Biochemistry and Molecular Biology, University of Miami Miller School of Medicine, Miami, FL, 33136, USA
| | - Michal Toborek
- Department of Biochemistry and Molecular Biology, University of Miami Miller School of Medicine, Miami, FL, 33136, USA
- Institute of Physiotherapy and Health Sciences, The Jerzy Kukuczka Academy of Physical Education, Katowice, Poland
| | - Joice Stipursky
- Laboratório Compartilhado, Instituto de Ciências Biomédicas, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
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Rhea EM, Banks WA, Raber J. Insulin Resistance in Peripheral Tissues and the Brain: A Tale of Two Sites. Biomedicines 2022; 10:1582. [PMID: 35884888 PMCID: PMC9312939 DOI: 10.3390/biomedicines10071582] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2022] [Revised: 06/27/2022] [Accepted: 06/29/2022] [Indexed: 12/12/2022] Open
Abstract
The concept of insulin resistance has been around since a few decades after the discovery of insulin itself. To allude to the classic Charles Dicken's novel published 62 years before the discovery of insulin, in some ways, this is the best of times, as the concept of insulin resistance has expanded to include the brain, with the realization that insulin has a life beyond the regulation of glucose. In other ways, it is the worst of times as insulin resistance is implicated in devastating diseases, including diabetes mellitus, obesity, and Alzheimer's disease (AD) that affect the brain. Peripheral insulin resistance affects nearly a quarter of the United States population in adults over age 20. More recently, it has been implicated in AD, with the degree of brain insulin resistance correlating with cognitive decline. This has led to the investigation of brain or central nervous system (CNS) insulin resistance and the question of the relation between CNS and peripheral insulin resistance. While both may involve dysregulated insulin signaling, the two conditions are not identical and not always interlinked. In this review, we compare and contrast the similarities and differences between peripheral and CNS insulin resistance. We also discuss how an apolipoprotein involved in insulin signaling and related to AD, apolipoprotein E (apoE), has distinct pools in the periphery and CNS and can indirectly affect each system. As these systems are both separated but also linked via the blood-brain barrier (BBB), we discuss the role of the BBB in mediating some of the connections between insulin resistance in the brain and in the peripheral tissues.
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Affiliation(s)
- Elizabeth M. Rhea
- Department of Medicine, Division of Gerontology and Geriatric Medicine, University of Washington, Seattle, WA 98195, USA; (E.M.R.); (W.A.B.)
- Geriatric Research Education and Clinical Center, Veterans Affairs Puget Sound Health Care System, Seattle, WA 98108, USA
| | - William A. Banks
- Department of Medicine, Division of Gerontology and Geriatric Medicine, University of Washington, Seattle, WA 98195, USA; (E.M.R.); (W.A.B.)
- Geriatric Research Education and Clinical Center, Veterans Affairs Puget Sound Health Care System, Seattle, WA 98108, USA
| | - Jacob Raber
- Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, OR 97239, USA
- Departments of Neurology and Radiation Medicine, Division of Neuroscience, ONPRC, Oregon Health & Science University, Portland, OR 97239, USA
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Banks WA, Noonan C, Rhea EM, M. Rhea E. Evidence for an alternative insulin transporter at the blood-brain barrier. AGING PATHOBIOLOGY AND THERAPEUTICS 2022; 4:100-108. [PMID: 36644126 PMCID: PMC9837797 DOI: 10.31491/apt.2022.12.100] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Accumulating evidence suggests there is an alternative insulin transporter besides the insulin receptor at the blood-brain barrier (BBB), responsible for shuttling insulin from the circulation into the brain. In this review, we summarize key features of the BBB and what makes it unique compared to other capillary beds; summarize what we know about insulin BBB transport; provide an extensive list of diseases, physiological states, and serum factors tested in modifying insulin BBB transport; and lastly, highlight potential alternative transport systems that may be involved in or have already been tested in mediating insulin BBB transport. Identifying the transport system for insulin at the BBB would aide in controlling central nervous system (CNS) insulin levels in multiple diseases and conditions including Alzheimer's disease (AD) and obesity, where availability of insulin to the CNS is limited.
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Affiliation(s)
- William A. Banks
- Department of Medicine, Division of Gerontology and Geriatric Medicine, University of Washington, Seattle, WA 98195, USA.,Geriatric Research Education and Clinical Center, Veterans Affairs Puget Sound Health Care System, Seattle, WA 98108, USA
| | - Cassidy Noonan
- Research and Development, Veterans Affairs Puget Sound Health Care System, Seattle, WA 98108, USA.,University of Washington, Seattle, WA 98195, USA
| | - Elizabeth M. Rhea
- Department of Medicine, Division of Gerontology and Geriatric Medicine, University of Washington, Seattle, WA 98195, USA.,Geriatric Research Education and Clinical Center, Veterans Affairs Puget Sound Health Care System, Seattle, WA 98108, USA.,Corresponding author: Elizabeth M. Rhea, Mailing address: 1660 S. Columbian Way, Seattle, WA 98108, USA.
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