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Zhang Y, Li T, Miao J, Zhang Z, Yang M, Wang Z, Yang B, Zhang J, Li H, Su Q, Guo J. Gamma-glutamyl transferase 5 overexpression in cerebrovascular endothelial cells improves brain pathology, cognition, and behavior in APP/PS1 mice. Neural Regen Res 2025; 20:533-547. [PMID: 38819065 PMCID: PMC11317949 DOI: 10.4103/nrr.nrr-d-23-01525] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2023] [Revised: 12/18/2023] [Accepted: 02/21/2024] [Indexed: 06/01/2024] Open
Abstract
JOURNAL/nrgr/04.03/01300535-202502000-00030/figure1/v/2024-05-28T214302Z/r/image-tiff In patients with Alzheimer's disease, gamma-glutamyl transferase 5 (GGT5) expression has been observed to be downregulated in cerebrovascular endothelial cells. However, the functional role of GGT5 in the development of Alzheimer's disease remains unclear. This study aimed to explore the effect of GGT5 on cognitive function and brain pathology in an APP/PS1 mouse model of Alzheimer's disease, as well as the underlying mechanism. We observed a significant reduction in GGT5 expression in two in vitro models of Alzheimer's disease (Aβ1-42-treated hCMEC/D3 and bEnd.3 cells), as well as in the APP/PS1 mouse model. Additionally, injection of APP/PS1 mice with an adeno-associated virus encoding GGT5 enhanced hippocampal synaptic plasticity and mitigated cognitive deficits. Interestingly, increasing GGT5 expression in cerebrovascular endothelial cells reduced levels of both soluble and insoluble amyloid-β in the brains of APP/PS1 mice. This effect may be attributable to inhibition of the expression of β-site APP cleaving enzyme 1, which is mediated by nuclear factor-kappa B. Our findings demonstrate that GGT5 expression in cerebrovascular endothelial cells is inversely associated with Alzheimer's disease pathogenesis, and that GGT5 upregulation mitigates cognitive deficits in APP/PS1 mice. These findings suggest that GGT5 expression in cerebrovascular endothelial cells is a potential therapeutic target and biomarker for Alzheimer's disease.
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Affiliation(s)
- Yanli Zhang
- Department of Neurology, First Hospital of Shanxi Medical University, Taiyuan, Shanxi Province, China
- Department of Neurology, Sixth Hospital of Shanxi Medical University (General Hospital of Tisco), Taiyuan, Shanxi Province, China
| | - Tian Li
- Department of Physiology, Key Laboratory of Cellular Physiology, Ministry of Education, Shanxi Medical University, Taiyuan, Shanxi Province, China
| | - Jie Miao
- Department of Neurology, First Hospital of Shanxi Medical University, Taiyuan, Shanxi Province, China
| | - Zhina Zhang
- Department of Neurology, First Hospital of Shanxi Medical University, Taiyuan, Shanxi Province, China
| | - Mingxuan Yang
- Department of Neurology, First Hospital of Shanxi Medical University, Taiyuan, Shanxi Province, China
| | - Zhuoran Wang
- Department of Neurology, First Hospital of Shanxi Medical University, Taiyuan, Shanxi Province, China
| | - Bo Yang
- Department of Hernia and Abdominal Wall Surgery, Shanxi Bethune Hospital, Shanxi Academy of Medical Sciences, Tongji Shanxi Hospital, Third Hospital of Shanxi Medical University, Taiyuan, Shanxi Province, China
| | - Jiawei Zhang
- Department of Neurology, First Hospital of Shanxi Medical University, Taiyuan, Shanxi Province, China
| | - Haiting Li
- Department of Neurology, First Hospital of Shanxi Medical University, Taiyuan, Shanxi Province, China
| | - Qiang Su
- Department of Physiology, Key Laboratory of Cellular Physiology, Ministry of Education, Shanxi Medical University, Taiyuan, Shanxi Province, China
- Department of Laboratory Medicine of Fenyang College, Shanxi Medical University, Fenyang, Shanxi Province, China
| | - Junhong Guo
- Department of Neurology, First Hospital of Shanxi Medical University, Taiyuan, Shanxi Province, China
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Zhang Q, Yan Y. The role of natural flavonoids on neuroinflammation as a therapeutic target for Alzheimer's disease: a narrative review. Neural Regen Res 2023; 18:2582-2591. [PMID: 37449593 DOI: 10.4103/1673-5374.373680] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/18/2023] Open
Abstract
Alzheimer's disease is a neurodegenerative disease that affects a large proportion of older adult people and is characterized by memory loss, progressive cognitive impairment, and various behavioral disturbances. Although the pathological mechanisms underlying Alzheimer's disease are complex and remain unclear, previous research has identified two widely accepted pathological characteristics: extracellular neuritic plaques containing amyloid beta peptide, and intracellular neurofibrillary tangles containing tau. Furthermore, research has revealed the significant role played by neuroinflammation over recent years. The inflammatory microenvironment mainly consists of microglia, astrocytes, the complement system, chemokines, cytokines, and reactive oxygen intermediates; collectively, these factors can promote the pathological process and aggravate the severity of Alzheimer's disease. Therefore, the development of new drugs that can target neuroinflammation will be a significant step forward for the treatment of Alzheimer's disease. Flavonoids are plant-derived secondary metabolites that possess various bioactivities. Previous research found that multiple natural flavonoids could exert satisfactory treatment effects on the neuroinflammation associated with Alzheimer's disease. In this review, we describe the pathogenesis and neuroinflammatory processes of Alzheimer's disease, and summarize the effects and mechanisms of 13 natural flavonoids (apigenin, luteolin, naringenin, quercetin, morin, kaempferol, fisetin, isoquercitrin, astragalin, rutin, icariin, mangiferin, and anthocyanin) derived from plants or medicinal herbs on neuroinflammation in Alzheimer's disease. As an important resource for the development of novel compounds for the treatment of critical diseases, it is essential that we focus on the exploitation of natural products. In particular, it is vital that we investigate the effects of flavonoids on the neuroinflammation associated with Alzheimer's disease in greater detail.
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Affiliation(s)
- Qian Zhang
- National Engineering Laboratory for Resource Development of Endangered Crude Drugs in Northwest China; Key Laboratory of Medicinal Resources and Natural Pharmaceutical Chemistry, The Ministry of Education; College of Life Sciences, Shaanxi Normal University, Xi'an, Shaanxi Province, China
| | - Yaping Yan
- National Engineering Laboratory for Resource Development of Endangered Crude Drugs in Northwest China; Key Laboratory of Medicinal Resources and Natural Pharmaceutical Chemistry, The Ministry of Education; College of Life Sciences, Shaanxi Normal University, Xi'an, Shaanxi Province, China
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Ye X, Shao S, Wang Y, Su W. Ginsenoside Rg2 alleviates neurovascular damage in 3xTg-AD mice with Alzheimer's disease through the MAPK-ERK pathway. J Chem Neuroanat 2023; 133:102346. [PMID: 37805189 DOI: 10.1016/j.jchemneu.2023.102346] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2023] [Revised: 09/18/2023] [Accepted: 10/01/2023] [Indexed: 10/09/2023]
Abstract
Alzheimer's disease (AD) is the most common form of dementia, and ginsenoside Rg2 (Rg2) is proven to inhibit AD's progression. This study investigates the potential benefits of Rg2 treatment on 3xTg-AD mice. Following 6 weeks of gavage treatment, Rg2-treated 3xTg-AD mice exhibited improved spatial recognition memory behaviors, regional cerebral blood flow, and histopathological injury of the hippocampus, which were observed through a Y-maze test, laser Doppler flowmetry, and hematoxylin-eosin staining. Additionally, Rg2 treatment caused a decrease in the levels of amyloid beta 25-35, TNF-α, IL-1β, and IL-6, as measured by enzyme-linked immunosorbent assay, as well as a reduction in mRNA levels of IL-1β and IL-6 in 3xTg-AD mouse brains using quantitative real-time PCR. In particular, NeuN and CD31 levels were inhibited and GFAP level was elevated in 3xTg-AD mice that were observed through immunofluorescence, and these levels were all antagonized by Rg2, suggesting the effects of Rg2 on neurovascular damage, astrocyte activation, and neuronal loss. Furthermore, Western blot and qRT-PCR assays showed that Rg2 blocked the expression of ICAM-1 and VCAM-1 in 3xTg-AD mice. By Western blot, the ratios of p-ERK/ERK and p-MAPK/MAPK in 3xTg-AD mice were upregulated by Rg2 treatment, suggesting the neuroprotective effects of Rg2 may be related to the MAPK-ERK pathway. In summary, this study demonstrated the potential of Rg2 to improve AD and provided a scientific basis for research on the biological mechanism of AD and the development of Rg2.
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Affiliation(s)
- Xiaojun Ye
- Department of Neurology, The Affiliated Hospital of Hangzhou Normal University, Hangzhou, Zhejiang 310015, China
| | - Sen Shao
- Department of Neurology, The Xixi Hospital of Hangzhou Affiliated to Zhejiang University School of Medicine, Hangzhou, Zhejiang 310023, China
| | - Yanbo Wang
- Department of Neurology, The Third Affiliated Hospital of Zhejiang Chinese Medicine University, Hangzhou, Zhejiang 310000, China
| | - Wenwen Su
- Department of Internal Medicine, Cixi Seventh People's Hospital, Ningbo, Zhejiang 315000, China.
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Zhou J, Singh N, Galske J, Hudobenko J, Hu X, Yan R. BACE1 regulates expression of Clusterin in astrocytes for enhancing clearance of β-amyloid peptides. Mol Neurodegener 2023; 18:31. [PMID: 37143090 PMCID: PMC10161466 DOI: 10.1186/s13024-023-00611-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2023] [Accepted: 03/07/2023] [Indexed: 05/06/2023] Open
Abstract
BACKGROUND Abnormal accumulation of amyloid beta peptide (Aβ) in the brain induces a cascade of pathological changes in Alzheimer's disease (AD), and inhibiting BACE1, which is required for Aβ generation, is therefore being explored for the treatment of AD by reducing Aβ accumulation. As Bace1 knockout mice exhibit increased number of reactive astrocytes and AD brains have reactive astrocytes that surround amyloid plaques, we investigated the role of BACE1 in astrocytes and determined whether BACE1 regulates astrocytic functions. METHODS We conducted unbiased single cell RNA-seq (scRNA-seq) using purified astrocytes from Bace1 KO mice and wild type control littermates. Similar scRNA-seq was also conducted using AD mice with conditional deletion of Bace1 in the adult stage (5xFAD;Bace1fl/fl;UBC-creER compared to 5xFAD;Bace1fl/fl controls). We compared the transcriptomes of astrocyte and reactive astrocyte clusters and identified several differentially expressed genes, which were further validated using Bace1 KO astrocyte cultures. Mice with astrocyte-specific Bace1 knockout in 5xFAD background were used to compare amyloid deposition. Mechanistic studies using cultured astrocytes were used to identify BACE1 substrates for changes in gene expression and signaling activity. RESULTS Among altered genes, Clusterin (Clu) and Cxcl14 were significantly upregulated and validated by measuring protein levels. Moreover, BACE1 deficiency enhanced both astrocytic Aβ uptake and degradation, and this effect was significantly attenuated by siRNA knockdown of Clu. Mechanistic study suggests that BACE1 deficiency abolishes cleavage of astrocytic insulin receptors (IR), and this may enhance expression of Clu and Cxcl14. Acutely isolated astrocytes from astrocyte-specific knockout of Bace1 mice (Bace1 fl/fl;Gfap-cre) show similar increases in CLU and IR. Furthermore, astrocyte-specific knockout of Bace1 in a 5xFAD background resulted in a significant attenuation in cortical Aβ plaque load through enhanced clearance. CONCLUSION Together, our study suggests that BACE1 in astrocytes regulates expression of Clu and Cxcl14, likely via the control of insulin receptor pathway, and inhibition of astrocytic BACE1 is a potential alternative strategy for enhancing Aβ clearance.
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Affiliation(s)
- John Zhou
- Department of Neuroscience, UConn Health, 263 Farmington Avenue, Farmington, CT, 06030-3401, USA
- Department of Molecular Medicine, Cleveland Clinic Lerner College of Medicine, Case Western Reserve University, Cleveland, OH, 44195, United States
- Department of Neuroscience, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, 44195, United States
| | - Neeraj Singh
- Department of Neuroscience, UConn Health, 263 Farmington Avenue, Farmington, CT, 06030-3401, USA
| | - James Galske
- Department of Neuroscience, UConn Health, 263 Farmington Avenue, Farmington, CT, 06030-3401, USA
| | - Jacob Hudobenko
- Department of Neuroscience, UConn Health, 263 Farmington Avenue, Farmington, CT, 06030-3401, USA
| | - Xiangyou Hu
- Department of Neuroscience, UConn Health, 263 Farmington Avenue, Farmington, CT, 06030-3401, USA
| | - Riqiang Yan
- Department of Neuroscience, UConn Health, 263 Farmington Avenue, Farmington, CT, 06030-3401, USA.
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Montero-Cosme TG, Pascual-Mathey LI, Hernández-Aguilar ME, Herrera-Covarrubias D, Rojas-Durán F, Aranda-Abreu GE. Potential drugs for the treatment of Alzheimer's disease. Pharmacol Rep 2023; 75:544-559. [PMID: 37005970 DOI: 10.1007/s43440-023-00481-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2023] [Revised: 03/24/2023] [Accepted: 03/26/2023] [Indexed: 04/04/2023]
Abstract
It is well known that amyloid precursor protein (APP), the enzyme β-secretase 1 (BACE1), cyclooxygenase 2 (COX-2), nicastrin (NCT), and hyperphosphorylated tau protein (p-tau) are closely related to the development of Alzheimer's disease (AD). In addition, recent evidence shows that neuroinflammation also contributes to the pathogenesis of AD. Although the mechanism is not clearly known, such inflammation could alter the activity of the aforementioned molecules. Therefore, the use of anti-inflammatory agents could slow the progression of the disease. Nimesulide, resveratrol, and citalopram are three anti-inflammatory agents that could contribute to a decrease in neuroinflammation and consequently to a decrease in the overexpression of APP, BACE1, COX-2, NCT, and p-Tau, as they possess anti-inflammatory effects that could regulate the expression of APP, BACE1, COX-2, NCT, and p-Tau of potent pro-inflammatory markers indirectly involved in the expression of APP, BACE1, NCT, COX-2, and p-Tau; therefore, their use could be beneficial as preventive treatment as well as in the early stages of AD.
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Affiliation(s)
| | | | | | | | - Fausto Rojas-Durán
- Instituto de Investigaciones Cerebrales, Universidad Veracruzana, Xalapa, Veracruz, México
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Natale G, Zhang Y, Hanes DW, Clouston SAP. Obesity in Late-Life as a Protective Factor Against Dementia and Dementia-Related Mortality. Am J Alzheimers Dis Other Demen 2023; 38:15333175221111658. [PMID: 37391890 PMCID: PMC10580725 DOI: 10.1177/15333175221111658] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/02/2023]
Abstract
OBJECTIVE We estimated the conversion from cognitively normal to mild cognitive impairment (MCI) to probable dementia and death for underweight, normal, overweight, and obese older adults, where the timing of examinations is associated with the severity of dementia. METHODS We analyzed six waves of the National Health and Aging Trends Study (NHATS). Body mass (BMI) was computed from height and weight. Multi-state survival models (MSMs) examined misclassification probability, time-to-event ratios, and cognitive decline. RESULTS Participants (n = 6078) were 77 years old, 62% had overweight and/or obese BMI. After adjusting for the effects of cardiometabolic factors, age, sex, and race, obesity was protective against developing dementia (aHR=.44; 95%CI [.29-.67]) and dementia-related mortality (aHR=.63; 95%CI [.42-.95]). DISCUSSION We found a negative relationship between obesity and dementia and dementia-related mortality, a finding that has been underreported in the literature. The continuing obesity epidemic might complicate the diagnosis and treatment of dementia.
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Affiliation(s)
- Ginny Natale
- Program in Public Health and Department of Family, Population, and Preventive Medicine, Stony Brook University, Stony Brook, NY, USA
| | - Yun Zhang
- Program in Public Health and Department of Family, Population, and Preventive Medicine, Stony Brook University, Stony Brook, NY, USA
| | - Douglas William Hanes
- Program in Public Health and Department of Family, Population, and Preventive Medicine, Stony Brook University, Stony Brook, NY, USA
| | - Sean AP Clouston
- Program in Public Health and Department of Family, Population, and Preventive Medicine, Stony Brook University, Stony Brook, NY, USA
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Abstract
PURPOSE OF REVIEW An epidemic of age-associated cognitive decline, most commonly ascribed to neurodegenerative conditions such as Alzheimer's and Parkinson's disease, is causing healthcare costs to soar and devastating caregivers. An estimated 6.5 million Americans are living today with Alzheimer's disease, with 13.8 million cases projected by mid-century. Although genetic mutations are known to cause neurodegeneration, autosomal dominant disease is very rare and most sporadic cases can be attributed, at least in part, to modifiable risk factors. RECENT FINDINGS Diet is a potential modifiable risk factor in cognitive decline. Food communicates with the brain through a complex signaling web involving multiple cells, mediators and receptors. Gut-brain communication is modulated by microorganisms including bacteria, archaea, viruses, and unicellular eukaryotes, which together constitute the microbiota. Microbes not only play major roles in the digestion and fermentation of the food, providing nutrients and bioactive metabolites, but also reflect the type and amount of food consumed and food-borne toxic exposures. Food components modify the diversity and abundance of the microbial populations, maintain the integrity of the gut barrier, and regulate the passage of microbes and their metabolites into the blood stream where they modulate the immune system and communicate with body systems including the brain. This paper will focus on selected mechanisms through which interactions between diet and the gut microbiota can modify brain integrity and cognitive function with emphasis on the pathogenesis of the most common dementia, Alzheimer's disease.
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Affiliation(s)
- Susan Ettinger
- Interdisciplinary Health Sciences, New York Institute of Technology, New York, USA.
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Kettunen P, Bjerke M, Eckerström C, Jonsson M, Zetterberg H, Blennow K, Svensson J, Wallin A. Blood-brain barrier dysfunction and reduced cerebrospinal fluid levels of soluble amyloid precursor protein-β in patients with subcortical small-vessel disease. ALZHEIMER'S & DEMENTIA (AMSTERDAM, NETHERLANDS) 2022; 14:e12296. [PMID: 35356486 PMCID: PMC8949877 DOI: 10.1002/dad2.12296] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/05/2021] [Revised: 01/13/2022] [Accepted: 01/30/2022] [Indexed: 11/30/2022]
Abstract
Introduction Subcortical small-vessel disease (SSVD) is the most common vascular cognitive disorder. However, because no disease-specific cerebrospinal fluid (CSF) biomarkers are available for SSVD, our aim was to identify such markers. Methods We included 170 healthy controls and patients from the Gothenburg Mild Cognitive Impairment (MCI) study clinically diagnosed with SSVD dementia, Alzheimer's disease (AD), or mixed AD/SSVD. We quantified CSF levels of amyloid-β (Aβ)x-38, Aβx-40, Aβx-42, as well as soluble amyloid precursor protein (sAPP)-α and sAPP-β. Results sAPP-β was lower in SSVD patients than in AD patients and controls. Receiver-operating characteristic (ROC) analyses showed that sAPP-β moderately separated SSVD from AD and controls. Moreover, the CSF/serum albumin ratio was elevated exclusively in SSVD and could moderately separate SSVD from the other groups in ROC analyses. Discussion SSVD has a biomarker profile that differs from that of AD and controls, and to some extent also from mixed AD/SSVD, suggesting that signs of blood-brain barrier (BBB) dysfunction and sAPP-β could be additional tools to diagnose SSVD. Highlights Patients with subcortical small-vessel disease (SSVD) exhibited reduced levels of sAPP-β and disturbances of the blood-brain barrier (BBB).This biochemical pattern is different from that of Alzheimer's disease (AD) and to some degree from that of mixed AD/SSVD.Our findings are speaking in favor of the concept that SSVD is a distinct vascular cognitive disorder (VCD) form.
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Affiliation(s)
- Petronella Kettunen
- Department of Psychiatry and Neurochemistry, Institute of Neuroscience and Physiology, Sahlgrenska AcademyUniversity of GothenburgGothenburgSweden
| | - Maria Bjerke
- Laboratory of Neurochemistry, Department of Clinical Biology and Center for NeurosciencesUniversitair Ziekenhuis BrusselBrusselsBelgium
- Department of Biomedical SciencesInstitute Born‐BungeUniversity of AntwerpAntwerpBelgium
| | - Carl Eckerström
- Department of Psychiatry and Neurochemistry, Institute of Neuroscience and Physiology, Sahlgrenska AcademyUniversity of GothenburgGothenburgSweden
- Department of Immunology and Transfusion MedicineSahlgrenska University HospitalGothenburgSweden
| | - Michael Jonsson
- Department of Psychiatry and Neurochemistry, Institute of Neuroscience and Physiology, Sahlgrenska AcademyUniversity of GothenburgGothenburgSweden
| | - Henrik Zetterberg
- Department of Psychiatry and Neurochemistry, Institute of Neuroscience and Physiology, Sahlgrenska AcademyUniversity of GothenburgGothenburgSweden
- Clinical Neurochemistry LaboratorySahlgrenska University HospitalMölndalSweden
- Department of Neurodegenerative DiseaseUCL Institute of NeurologyLondonUK
- UK Dementia Research Institute at UCLLondonUK
- Hong Kong Center for Neurodegenerative DiseasesHong KongChina
| | - Kaj Blennow
- Department of Psychiatry and Neurochemistry, Institute of Neuroscience and Physiology, Sahlgrenska AcademyUniversity of GothenburgGothenburgSweden
- Clinical Neurochemistry LaboratorySahlgrenska University HospitalMölndalSweden
| | - Johan Svensson
- Department of Internal Medicine and Clinical Nutrition, Institute of Medicine, Sahlgrenska AcademyUniversity of GothenburgGothenburgSweden
- Region Västra Götaland, Department of Internal MedicineSkaraborg Central HospitalSkövdeSweden
| | - Anders Wallin
- Department of Psychiatry and Neurochemistry, Institute of Neuroscience and Physiology, Sahlgrenska AcademyUniversity of GothenburgGothenburgSweden
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Staurenghi E, Giannelli S, Testa G, Sottero B, Leonarduzzi G, Gamba P. Cholesterol Dysmetabolism in Alzheimer's Disease: A Starring Role for Astrocytes? Antioxidants (Basel) 2021; 10:antiox10121890. [PMID: 34943002 PMCID: PMC8750262 DOI: 10.3390/antiox10121890] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Revised: 11/22/2021] [Accepted: 11/24/2021] [Indexed: 01/19/2023] Open
Abstract
In recent decades, the impairment of cholesterol metabolism in the pathogenesis of Alzheimer’s disease (AD) has been intensively investigated, and it has been recognized to affect amyloid β (Aβ) production and clearance, tau phosphorylation, neuroinflammation and degeneration. In particular, the key role of cholesterol oxidation products, named oxysterols, has emerged. Brain cholesterol metabolism is independent from that of peripheral tissues and it must be preserved in order to guarantee cerebral functions. Among the cells that help maintain brain cholesterol homeostasis, astrocytes play a starring role since they deliver de novo synthesized cholesterol to neurons. In addition, other physiological roles of astrocytes are to modulate synaptic transmission and plasticity and support neurons providing energy. In the AD brain, astrocytes undergo significant morphological and functional changes that contribute to AD onset and development. However, the extent of this contribution and the role played by oxysterols are still unclear. Here we review the current understanding of the physiological role exerted by astrocytes in the brain and their contribution to AD pathogenesis. In particular, we focus on the impact of cholesterol dysmetabolism on astrocyte functions suggesting new potential approaches to develop therapeutic strategies aimed at counteracting AD development.
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Lecordier S, Manrique-Castano D, El Moghrabi Y, ElAli A. Neurovascular Alterations in Vascular Dementia: Emphasis on Risk Factors. Front Aging Neurosci 2021; 13:727590. [PMID: 34566627 PMCID: PMC8461067 DOI: 10.3389/fnagi.2021.727590] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2021] [Accepted: 08/05/2021] [Indexed: 12/25/2022] Open
Abstract
Vascular dementia (VaD) constitutes the second most prevalent cause of dementia in the world after Alzheimer’s disease (AD). VaD regroups heterogeneous neurological conditions in which the decline of cognitive functions, including executive functions, is associated with structural and functional alterations in the cerebral vasculature. Among these cerebrovascular disorders, major stroke, and cerebral small vessel disease (cSVD) constitute the major risk factors for VaD. These conditions alter neurovascular functions leading to blood-brain barrier (BBB) deregulation, neurovascular coupling dysfunction, and inflammation. Accumulation of neurovascular impairments over time underlies the cognitive function decline associated with VaD. Furthermore, several vascular risk factors, such as hypertension, obesity, and diabetes have been shown to exacerbate neurovascular impairments and thus increase VaD prevalence. Importantly, air pollution constitutes an underestimated risk factor that triggers vascular dysfunction via inflammation and oxidative stress. The review summarizes the current knowledge related to the pathological mechanisms linking neurovascular impairments associated with stroke, cSVD, and vascular risk factors with a particular emphasis on air pollution, to VaD etiology and progression. Furthermore, the review discusses the major challenges to fully elucidate the pathobiology of VaD, as well as research directions to outline new therapeutic interventions.
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Affiliation(s)
- Sarah Lecordier
- Neuroscience Axis, Research Center of CHU de Québec-Université Laval, Québec City, QC, Canada.,Department of Psychiatry and Neuroscience, Faculty of Medicine, Université Laval, Québec City, QC, Canada
| | - Daniel Manrique-Castano
- Neuroscience Axis, Research Center of CHU de Québec-Université Laval, Québec City, QC, Canada.,Department of Psychiatry and Neuroscience, Faculty of Medicine, Université Laval, Québec City, QC, Canada
| | - Yara El Moghrabi
- Neuroscience Axis, Research Center of CHU de Québec-Université Laval, Québec City, QC, Canada.,Department of Psychiatry and Neuroscience, Faculty of Medicine, Université Laval, Québec City, QC, Canada
| | - Ayman ElAli
- Neuroscience Axis, Research Center of CHU de Québec-Université Laval, Québec City, QC, Canada.,Department of Psychiatry and Neuroscience, Faculty of Medicine, Université Laval, Québec City, QC, Canada
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Hussain B, Fang C, Chang J. Blood-Brain Barrier Breakdown: An Emerging Biomarker of Cognitive Impairment in Normal Aging and Dementia. Front Neurosci 2021; 15:688090. [PMID: 34489623 PMCID: PMC8418300 DOI: 10.3389/fnins.2021.688090] [Citation(s) in RCA: 108] [Impact Index Per Article: 36.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Accepted: 07/14/2021] [Indexed: 12/11/2022] Open
Abstract
The blood–brain barrier (BBB) plays a vital role in maintaining the specialized microenvironment of the neural tissue. It separates the peripheral circulatory system from the brain parenchyma while facilitating communication. Alterations in the distinct physiological properties of the BBB lead to BBB breakdown associated with normal aging and various neurodegenerative diseases. In this review, we first briefly discuss the aging process, then review the phenotypes and mechanisms of BBB breakdown associated with normal aging that further cause neurodegeneration and cognitive impairments. We also summarize dementia such as Alzheimer's disease (AD) and vascular dementia (VaD) and subsequently discuss the phenotypes and mechanisms of BBB disruption in dementia correlated with cognition decline. Overlaps between AD and VaD are also discussed. Techniques that could identify biomarkers associated with BBB breakdown are briefly summarized. Finally, we concluded that BBB breakdown could be used as an emerging biomarker to assist to diagnose cognitive impairment associated with normal aging and dementia.
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Affiliation(s)
- Basharat Hussain
- Shenzhen Key Laboratory of Biomimetic Materials and Cellular Immunomodulation, Institute of Biomedicine and Biotechnology, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Cheng Fang
- Shenzhen Key Laboratory of Biomimetic Materials and Cellular Immunomodulation, Institute of Biomedicine and Biotechnology, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
| | - Junlei Chang
- Shenzhen Key Laboratory of Biomimetic Materials and Cellular Immunomodulation, Institute of Biomedicine and Biotechnology, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
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