1
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van den Berg E, Kersten I, Brinkmalm G, Johansson K, de Kort AM, Klijn CJ, Schreuder FH, Gobom J, Stoops E, Portelius E, Gkanatsiou E, Zetterberg H, Blennow K, Kuiperij HB, Verbeek MM. Profiling amyloid-β peptides as biomarkers for cerebral amyloid angiopathy. J Neurochem 2024; 168:1254-1264. [PMID: 38362804 PMCID: PMC11260253 DOI: 10.1111/jnc.16074] [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: 10/25/2023] [Revised: 01/08/2024] [Accepted: 01/24/2024] [Indexed: 02/17/2024]
Abstract
Brain amyloid-β (Aβ) deposits are key pathological hallmarks of both cerebral amyloid angiopathy (CAA) and Alzheimer's disease (AD). Microvascular deposits in CAA mainly consist of the Aβ40 peptide, whereas Aβ42 is the predominant variant in parenchymal plaques in AD. The relevance in pathogenesis and diagnostic accuracy of various other Aβ isoforms in CAA remain understudied. We aimed to investigate the biomarker potential of various Aβ isoforms in cerebrospinal fluid (CSF) to differentiate CAA from AD pathology. We included 25 patients with probable CAA, 50 subjects with a CSF profile indicative of AD pathology (AD-like), and 23 age- and sex-matched controls. CSF levels of Aβ1-34, Aβ1-37, Aβ1-38, Aβ1-39, Aβ1-40, and Aβ1-42 were quantified by liquid chromatography mass spectrometry. Lower CSF levels of all six Aβ peptides were observed in CAA patients compared with controls (p = 0.0005-0.03). Except for Aβ1-42 (p = 1.0), all peptides were decreased in CAA compared with AD-like subjects (p = 0.007-0.03). Besides Aβ1-42, none of the Aβ peptides were decreased in AD-like subjects compared with controls. All Aβ peptides combined differentiated CAA from AD-like subjects better (area under the curve [AUC] 0.84) than individual peptide levels (AUC 0.51-0.75). Without Aβ1-42 in the model (since decreased Aβ1-42 served as AD-like selection criterion), the AUC was 0.78 for distinguishing CAA from AD-like subjects. CAA patients and AD-like subjects showed distinct disease-specific CSF Aβ profiles. Peptides shorter than Aβ1-42 were decreased in CAA patients, but not AD-like subjects, which could suggest different pathological mechanisms between vascular and parenchymal Aβ accumulation. This study supports the potential use of this panel of CSF Aβ peptides to indicate presence of CAA pathology with high accuracy.
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Affiliation(s)
- Emma van den Berg
- Department of Neurology, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Iris Kersten
- Department of Neurology, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Gunnar Brinkmalm
- Institute of Neuroscience and Physiology, the Sahlgrenska Academy at the University of Gothenburg, Mölndal, Sweden
- Clinical Neurochemistry Laboratory, Sahlgrenska University Hospital, Mölndal, Sweden
| | - Kjell Johansson
- Clinical Neurochemistry Laboratory, Sahlgrenska University Hospital, Mölndal, Sweden
| | - Anna M. de Kort
- Department of Neurology, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Catharina J.M. Klijn
- Department of Neurology, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Floris H.B.M. Schreuder
- Department of Neurology, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Johan Gobom
- Institute of Neuroscience and Physiology, the Sahlgrenska Academy at the University of Gothenburg, Mölndal, Sweden
- Clinical Neurochemistry Laboratory, Sahlgrenska University Hospital, Mölndal, Sweden
| | | | - Erik Portelius
- Clinical Neurochemistry Laboratory, Sahlgrenska University Hospital, Mölndal, Sweden
| | - Eleni Gkanatsiou
- Institute of Neuroscience and Physiology, the Sahlgrenska Academy at the University of Gothenburg, Mölndal, Sweden
- Clinical Neurochemistry Laboratory, Sahlgrenska University Hospital, Mölndal, Sweden
| | - Henrik Zetterberg
- Clinical Neurochemistry Laboratory, Sahlgrenska University Hospital, Mölndal, Sweden
- Department of Psychiatry and Neurochemistry, Institute of Neuroscience and Physiology, the Sahlgrenska Academy at the University of Gothenburg, Mölndal, Sweden
- UK Dementia Research Institute at UCL, London, United Kingdom
- Department of Neurodegenerative Disease, UCL Institute of Neurology, London, United Kingdom
- Hong Kong Center for Neurodegenerative Diseases, Clear Water Bay, Hong Kong, China
- Wisconsin Alzheimer’s Disease Research Center, University of Wisconsin School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI, USA
| | - Kaj Blennow
- Institute of Neuroscience and Physiology, the Sahlgrenska Academy at the University of Gothenburg, Mölndal, Sweden
- Clinical Neurochemistry Laboratory, Sahlgrenska University Hospital, Mölndal, Sweden
| | - H. Bea Kuiperij
- Department of Neurology, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Marcel M. Verbeek
- Department of Neurology, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, The Netherlands
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands
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2
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Ulku I, Leung R, Herre F, Walther L, Shobo A, Saftig P, Hancock MA, Liebsch F, Multhaup G. Inhibition of BACE1 affected both its Aβ producing and degrading activities and increased Aβ42 and Aβ40 levels at high level BACE1 expression. J Biol Chem 2024:107510. [PMID: 38944120 DOI: 10.1016/j.jbc.2024.107510] [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: 02/28/2024] [Revised: 06/14/2024] [Accepted: 06/20/2024] [Indexed: 07/01/2024] Open
Abstract
The beta-site amyloid precursor protein cleaving enzyme 1 (BACE1) is the predominant β-secretase, cleaving the amyloid precursor protein (APP) via the amyloidogenic pathway. In addition, BACE1 as an amyloid degrading enzyme (ADE), cleaves Aβ to produce the C-terminally truncated non-toxic Aβ fragment Aβ34 which is an indicator of amyloid clearance. Here, we analyzed effects of BACE1 inhibitors on its opposing enzymatic functions, i.e., amyloidogenic (Aβ producing) and amyloidolytic (Aβ degrading) activities, using cell culture models with varying BACE1/APP ratios. Under high level BACE1 expression, low-dose inhibition unexpectedly yielded a two-fold increase in Aβ42 and Aβ40 levels. The concomitant decrease in Aβ34 and secreted APPβ levels suggested that the elevated Aβ42 and Aβ40 levels were due to the attenuated Aβ degrading activity of BACE1. Notably, the amyloidolytic activity of BACE1 was impeded at lower BACE1 inhibitor concentrations compared to its amyloidogenic activity, thereby suggesting that the Aβ degrading activity of BACE1 was more sensitive to inhibition than its Aβ producing activity. Under endogenous BACE1 and APP levels, "low-dose" BACE1 inhibition affected both the Aβ producing and degrading activities of BACE1, i.e., significantly increased Aβ42/Aβ40 ratio and decreased Aβ34 levels, respectively. Further, we incubated recombinant BACE1 with synthetic Aβ peptides and found that BACE1 has higher affinity for Aβ substrates over APP. In summary, our results suggest that stimulating BACE1's ADE activity and halting Aβ production without decreasing Aβ clearance could still be a promising therapeutic approach with new, yet to be developed, BACE1 modulators.
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Affiliation(s)
- Irem Ulku
- Department of Pharmacology and Therapeutics, McGill University, Montreal, QC H3G 1Y6, Canada; Integrated Program in Neuroscience, McGill University, Montreal, QC H3G 0B1, Canada
| | - Rocher Leung
- Department of Pharmacology and Therapeutics, McGill University, Montreal, QC H3G 1Y6, Canada
| | - Fritz Herre
- Department of Pharmacology and Therapeutics, McGill University, Montreal, QC H3G 1Y6, Canada
| | - Lina Walther
- Department of Pharmacology and Therapeutics, McGill University, Montreal, QC H3G 1Y6, Canada
| | - Adeola Shobo
- Department of Pharmacology and Therapeutics, McGill University, Montreal, QC H3G 1Y6, Canada
| | - Paul Saftig
- Biochemisches Institut, CAU Kiel, Olshausenstr, 40, 24098 Kiel, Germany
| | - Mark A Hancock
- Department of Pharmacology and Therapeutics, McGill University, Montreal, QC H3G 1Y6, Canada
| | - Filip Liebsch
- Department of Chemistry, Institute of Biochemistry, University of Cologne, 50674 Cologne, Germany
| | - Gerd Multhaup
- Department of Pharmacology and Therapeutics, McGill University, Montreal, QC H3G 1Y6, Canada; Integrated Program in Neuroscience, McGill University, Montreal, QC H3G 0B1, Canada.
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3
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Bohannon DG, Long D, Okhravi HR, Lee SC, De Jesus CL, Neubert TA, Rostagno AA, Ghiso JA, Kim WK. Functionally distinct pericyte subsets differently regulate amyloid-β deposition in patients with Alzheimer's disease. Brain Pathol 2024:e13282. [PMID: 38932696 DOI: 10.1111/bpa.13282] [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: 02/05/2024] [Accepted: 06/11/2024] [Indexed: 06/28/2024] Open
Abstract
Although the concept that the blood-brain barrier (BBB) plays an important role in the etiology and pathogenesis of Alzheimer's disease (AD) has become increasingly accepted, little is known yet about how it actually contributes. We and others have recently identified a novel functionally distinct subset of BBB pericytes (PCs). In the present study, we sought to determine whether these PC subsets differentially contribute to AD-associated pathologies by immunohistochemistry and amyloid beta (Aβ) peptidomics. We demonstrated that a disease-associated PC subset (PC2) expanded in AD patients compared to age-matched, cognitively unimpaired controls. Surprisingly, we found that this increase in the percentage of PC2 (%PC2) was correlated negatively with BBB breakdown in AD patients, unlike in natural aging or other reported disease conditions. The higher %PC2 in AD patients was also correlated with a lower Aβ42 plaque load and a lower Aβ42:Aβ40 ratio in the brain as determined by immunohistochemistry. Colocalization analysis of multicolor confocal immunofluorescence microscopy images suggests that AD patient with low %PC2 have higher BBB breakdown due to internalization of Aβ42 by the physiologically normal PC subset (PC1) and their concomitant cell death leading to more vessels without PCs and increased plaque load. On the contrary, it appears that PC2 can secrete cathepsin D to cleave and degrade Aβ built up outside of PC2 into more soluble forms, ultimately contributing to less BBB breakdown and reducing Aβ plaque load. Collectively our data shows functionally distinct mechanisms for PC1 and PC2 in high Aβ conditions, demonstrating the importance of correctly identifying these populations when investigating the contribution of neurovascular dysfunction to AD pathogenesis.
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Affiliation(s)
- Diana G Bohannon
- Department of Microbiology and Molecular Cell Biology, Eastern Virginia Medical School, Norfolk, Virginia, USA
| | - Danielle Long
- Department of Microbiology and Molecular Cell Biology, Eastern Virginia Medical School, Norfolk, Virginia, USA
| | - Hamid R Okhravi
- Glennan Center for Geriatrics and Gerontology, Eastern Virginia Medical School, Norfolk, Virginia, USA
- Integrated Neurodegenerative Disorders Center, Eastern Virginia Medical School, Norfolk, Virginia, USA
| | - Sunhee C Lee
- Regeneron Pharmaceuticals, Inc, Tarrytown, New York, USA
| | | | - Thomas A Neubert
- Department of Neuroscience and Physiology, New York University Grossman School of Medicine, New York, New York, USA
| | - Agueda A Rostagno
- Department of Pathology, New York University Grossman School of Medicine, New York, New York, USA
| | - Jorge A Ghiso
- Department of Pathology, New York University Grossman School of Medicine, New York, New York, USA
- Department of Psychiatry, New York University Grossman School of Medicine, New York, New York, USA
| | - Woong-Ki Kim
- Department of Microbiology and Molecular Cell Biology, Eastern Virginia Medical School, Norfolk, Virginia, USA
- Integrated Neurodegenerative Disorders Center, Eastern Virginia Medical School, Norfolk, Virginia, USA
- Division of Microbiology, Tulane National Primate Research Center, Covington, Louisiana, USA
- Department of Microbiology and Immunology, Tulane University School of Medicine, New Orleans, Louisiana, USA
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4
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Morris GP, Foster CG, Courtney J, Collins JM, Cashion JM, Brown LS, Howells DW, DeLuca GC, Canty AJ, King AE, Ziebell JM, Sutherland BA. Microglia directly associate with pericytes in the central nervous system. Glia 2023; 71:1847-1869. [PMID: 36994950 PMCID: PMC10952742 DOI: 10.1002/glia.24371] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2023] [Revised: 03/15/2023] [Accepted: 03/20/2023] [Indexed: 03/31/2023]
Abstract
Cerebral blood flow (CBF) is important for the maintenance of brain function and its dysregulation has been implicated in Alzheimer's disease (AD). Microglia associations with capillaries suggest they may play a role in the regulation of CBF or the blood-brain-barrier (BBB). We explored the relationship between microglia and pericytes, a vessel-resident cell type that has a major role in the control of CBF and maintenance of the BBB, discovering a spatially distinct subset of microglia that closely associate with pericytes. We termed these pericyte-associated microglia (PEM). PEM are present throughout the brain and spinal cord in NG2DsRed × CX3 CR1+/GFP mice, and in the human frontal cortex. Using in vivo two-photon microscopy, we found microglia residing adjacent to pericytes at all levels of the capillary tree and found they can maintain their position for at least 28 days. PEM can associate with pericytes lacking astroglial endfeet coverage and capillary vessel width is increased beneath pericytes with or without an associated PEM, but capillary width decreases if a pericyte loses a PEM. Deletion of the microglia fractalkine receptor (CX3 CR1) did not disrupt the association between pericytes and PEM. Finally, we found the proportion of microglia that are PEM declines in the superior frontal gyrus in AD. In summary, we identify microglia that specifically associate with pericytes and find these are reduced in number in AD, which may be a novel mechanism contributing to vascular dysfunction in neurodegenerative diseases.
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Affiliation(s)
- Gary P. Morris
- Tasmanian School of Medicine, College of Health and MedicineUniversity of TasmaniaHobartTasmaniaAustralia
| | - Catherine G. Foster
- Tasmanian School of Medicine, College of Health and MedicineUniversity of TasmaniaHobartTasmaniaAustralia
| | - Jo‐Maree Courtney
- Tasmanian School of Medicine, College of Health and MedicineUniversity of TasmaniaHobartTasmaniaAustralia
| | - Jessica M. Collins
- Wicking Dementia Research and Education Centre, College of Health and MedicineUniversity of TasmaniaHobartTasmaniaAustralia
| | - Jake M. Cashion
- Tasmanian School of Medicine, College of Health and MedicineUniversity of TasmaniaHobartTasmaniaAustralia
| | - Lachlan S. Brown
- Tasmanian School of Medicine, College of Health and MedicineUniversity of TasmaniaHobartTasmaniaAustralia
| | - David W. Howells
- Tasmanian School of Medicine, College of Health and MedicineUniversity of TasmaniaHobartTasmaniaAustralia
| | - Gabriele C. DeLuca
- Nuffield Department of Clinical NeurosciencesUniversity of OxfordOxfordUK
| | - Alison J. Canty
- Wicking Dementia Research and Education Centre, College of Health and MedicineUniversity of TasmaniaHobartTasmaniaAustralia
- Global Brain Health InstituteTrinity CollegeDublinIreland
| | - Anna E. King
- Wicking Dementia Research and Education Centre, College of Health and MedicineUniversity of TasmaniaHobartTasmaniaAustralia
| | - Jenna M. Ziebell
- Wicking Dementia Research and Education Centre, College of Health and MedicineUniversity of TasmaniaHobartTasmaniaAustralia
| | - Brad A. Sutherland
- Tasmanian School of Medicine, College of Health and MedicineUniversity of TasmaniaHobartTasmaniaAustralia
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5
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Madsen LS, Parbo P, Ismail R, Gottrup H, Østergaard L, Brooks DJ, Eskildsen SF. Capillary dysfunction correlates with cortical amyloid load in early Alzheimer's disease. Neurobiol Aging 2023; 123:1-9. [PMID: 36610198 DOI: 10.1016/j.neurobiolaging.2022.12.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2022] [Revised: 12/09/2022] [Accepted: 12/12/2022] [Indexed: 12/23/2022]
Abstract
Alterations in cerebral perfusion is increasingly considered to play a crucial role in Alzheimer's disease (AD) and together with accumulated amyloid-β, deficiencies in the brain microvascular circulation may result in local hypoxia. Here, we studied alterations in cerebral circulation and the correlation between amyloid-β load and cerebral perfusion in prodromal AD (pAD). Using dynamic susceptibility contrast MRI and PET, we evaluated cerebral perfusion and amyloid-β levels in 19 individuals with mild cognitive impairment (MCI) and high amyloid-β load (pAD-MCI), 13 MCI individuals without AD pathology and 21 healthy controls. The pAD-MCI group showed significantly lower microvascular blood flow and significantly higher heterogeneity of microvascular blood transit times (p < 0.01) compared with the other 2 groups. Additionally, in the pAD-MCI group raised amyloid-β levels correlated with decreased microvascular blood flow and increased heterogeneity of microvascular blood flow in frontal and temporal areas (p < 0.01). These results indicate a close connection between levels of amyloid-β deposition and brain microvascular perfusion in pAD. A vicious cycle may be established where amyloid-β load and deficiencies in brain perfusion may reinforce each other.
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Affiliation(s)
- Lasse S Madsen
- Department of Nuclear Medicine and PET-Centre, Aarhus University Hospital, Aarhus, Denmark; Center of Functionally Integrative Neuroscience, Department of Clinical Medicine, Aarhus University, Aarhus, Denmark.
| | - Peter Parbo
- Department of Nuclear Medicine, Odense University Hospital, Odense, Denmark
| | - Rola Ismail
- Department of Nuclear Medicine, Sygehus Lillebaelt, Kolding, Denmark
| | - Hanne Gottrup
- Dementia Clinic, Department of Neurology, Aarhus University Hospital, Aarhus, Denmark
| | - Leif Østergaard
- Center of Functionally Integrative Neuroscience, Department of Clinical Medicine, Aarhus University, Aarhus, Denmark; Department of Neuroradiology, Aarhus University Hospital, Aarhus, Denmark
| | - David J Brooks
- Department of Nuclear Medicine and PET-Centre, Aarhus University Hospital, Aarhus, Denmark; Institute of Translational and Clinical Research, University of Newcastle upon Tyne, Newcastle, UK
| | - Simon F Eskildsen
- Center of Functionally Integrative Neuroscience, Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
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6
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Ulku I, Liebsch F, Akerman SC, Schulz JF, Kulic L, Hock C, Pietrzik C, Di Spiezio A, Thinakaran G, Saftig P, Multhaup G. Mechanisms of amyloid-β34 generation indicate a pivotal role for BACE1 in amyloid homeostasis. Sci Rep 2023; 13:2216. [PMID: 36750595 PMCID: PMC9905473 DOI: 10.1038/s41598-023-28846-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2022] [Accepted: 01/25/2023] [Indexed: 02/09/2023] Open
Abstract
The beta‑site amyloid precursor protein (APP) cleaving enzyme (BACE1) was discovered due to its "amyloidogenic" activity which contributes to the production of amyloid-beta (Aβ) peptides. However, BACE1 also possesses an "amyloidolytic" activity, whereby it degrades longer Aβ peptides into a non‑toxic Aβ34 intermediate. Here, we examine conditions that shift the equilibrium between BACE1 amyloidogenic and amyloidolytic activities by altering BACE1/APP ratios. In Alzheimer disease brain tissue, we found an association between elevated levels of BACE1 and Aβ34. In mice, the deletion of one BACE1 gene copy reduced BACE1 amyloidolytic activity by ~ 50%. In cells, a stepwise increase of BACE1 but not APP expression promoted amyloidolytic cleavage resulting in dose-dependently increased Aβ34 levels. At the cellular level, a mislocalization of surplus BACE1 caused a reduction in Aβ34 levels. To align the role of γ-secretase in this pathway, we silenced Presenilin (PS) expression and identified PS2-γ-secretase as the main γ-secretase that generates Aβ40 and Aβ42 peptides serving as substrates for BACE1's amyloidolytic cleavage to generate Aβ34.
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Affiliation(s)
- Irem Ulku
- Integrated Program in Neuroscience, McGill University, Montreal, QC, H3G 0B1, Canada
| | - Filip Liebsch
- Integrated Program in Neuroscience, McGill University, Montreal, QC, H3G 0B1, Canada.,Department of Chemistry, Institute of Biochemistry, University of Cologne, 50674, Cologne, Germany
| | - S Can Akerman
- Department of Pharmacology and Therapeutics, McGill University, Montreal, QC, H3G 1Y6, Canada
| | - Jana F Schulz
- Institut Für Chemie Und Biochemie, Freie Universität Berlin, 14195, Berlin, Germany.,Cardiovascular and Metabolic Sciences, Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), 13125, Berlin, Germany
| | - Luka Kulic
- Roche Pharma Research & Early Development, F.Hoffmann-La Roche Ltd., 4070, Basel, Switzerland
| | - Christoph Hock
- Institute for Regenerative Medicine, Un Iversity of Zurich, 8952, Schlieren, Switzerland.,Neurimmune AG, 8952, Schlieren, Switzerland
| | - Claus Pietrzik
- Department Molecular Neurodegeneration, Institute of Pathobiochemistry, University Medical Center of the Johannes Gutenberg-University of Mainz, Duesbergweg 6, 55099, Mainz, Germany
| | | | - Gopal Thinakaran
- Department of Molecular Medicine and Byrd Alzheimer's Institute, University of South Florida, Tampa, FL, 33613, USA
| | - Paul Saftig
- Biochemisches Institut, CAU Kiel, Olshausenstr. 40, 24098, Kiel, Germany
| | - Gerhard Multhaup
- Integrated Program in Neuroscience, McGill University, Montreal, QC, H3G 0B1, Canada. .,Department of Pharmacology and Therapeutics, McGill University, Montreal, QC, H3G 1Y6, Canada.
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7
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Huang L, Lu Z, Zhang H, Wen H, Li Z, Liu Q, Wang R. A Novel Strategy for Alzheimer's Disease Based on the Regulatory Effect of Amyloid-β on Gut Flora. J Alzheimers Dis 2023; 94:S227-S239. [PMID: 36336932 PMCID: PMC10473151 DOI: 10.3233/jad-220651] [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] [Accepted: 09/19/2022] [Indexed: 06/16/2023]
Abstract
Alzheimer's disease (AD) is one of the most common neurodegenerative diseases worldwide. The accumulation of amyloid-β (Aβ) protein and plaque formation in the brain are two major causes of AD. Interestingly, growing evidence demonstrates that the gut flora can alleviate AD by affecting amyloid production and metabolism. However, the underlying mechanism remains largely unknown. This review will discuss the possible association between the gut flora and Aβ in an attempt to provide novel therapeutic directions for AD treatment based on the regulatory effect of Aβ on the gut flora.
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Affiliation(s)
- Li Huang
- School of Pharmacy, Ningxia Medical University, Yinchuan, China
| | - Zhaogang Lu
- Department of Pharmacy, People’s Hospital of Ningxia /First Affiliated Hospital of Northwest University for Nationalities, Yinchuan, China
| | - Hexin Zhang
- School of Pharmacy, Ningxia Medical University, Yinchuan, China
| | - Hongyong Wen
- School of Pharmacy, Ningxia Medical University, Yinchuan, China
| | - Zongji Li
- Laboratory Department, Clinical College of Ningxia Medical University, Yinchuan, China
| | - Qibing Liu
- Department of Pharmacology, Hainan Medical University, Haikou, China
| | - Rui Wang
- School of Pharmacy, Ningxia Medical University, Yinchuan, China
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8
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Hanbouch L, Schaack B, Kasri A, Fontaine G, Gkanatsiou E, Brinkmalm G, Camporesi E, Portelius E, Blennow K, Mourier G, Gilles N, Millan MJ, Marquer C, Zetterberg H, Boussicault L, Potier MC. Specific Mutations in the Cholesterol-Binding Site of APP Alter Its Processing and Favor the Production of Shorter, Less Toxic Aβ Peptides. Mol Neurobiol 2022; 59:7056-7073. [PMID: 36076005 PMCID: PMC9525381 DOI: 10.1007/s12035-022-03025-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2022] [Accepted: 08/31/2022] [Indexed: 12/05/2022]
Abstract
Excess brain cholesterol is strongly implicated in the pathogenesis of Alzheimer's disease (AD). Here we evaluated how the presence of a cholesterol-binding site (CBS) in the transmembrane and juxtamembrane regions of the amyloid precursor protein (APP) regulates its processing. We generated nine point mutations in the APP gene, changing the charge and/or hydrophobicity of the amino-acids which were previously shown as part of the CBS. Most mutations triggered a reduction of amyloid-β peptides Aβ40 and Aβ42 secretion from transiently transfected HEK293T cells. Only the mutations at position 28 of Aβ in the APP sequence resulted in a concomitant significant increase in the production of shorter Aβ peptides. Mass spectrometry (MS) confirmed the predominance of Aβx-33 and Aβx-34 with the APPK28A mutant. The enzymatic activity of α-, β-, and γ-secretases remained unchanged in cells expressing all mutants. Similarly, subcellular localization of the mutants in early endosomes did not differ from the APPWT protein. A transient increase of plasma membrane cholesterol enhanced the production of Aβ40 and Aβ42 by APPWT, an effect absent in APPK28A mutant. Finally, WT but not CBS mutant Aβ derived peptides bound to cholesterol-rich exosomes. Collectively, the present data revealed a major role of juxtamembrane amino acids of the APP CBS in modulating the production of toxic Aβ species. More generally, they underpin the role of cholesterol in the pathophysiology of AD.
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Affiliation(s)
- Linda Hanbouch
- Paris Brain Institute, ICM, CNRS UMR7225-INSERM U1127-Sorbonne University Hôpital de La Pitié-Salpêtrière, 47 Bd de l'Hôpital, 75013, Paris, France
| | - Béatrice Schaack
- Univ. Grenoble Alpes, CNRS, INP, TheRex Team, TIMC-IMAG, 38700, La Tronche, France
- Univ. Grenoble Alpes, CEA, CNRS, IBS, 38044, Grenoble, France
| | - Amal Kasri
- Paris Brain Institute, ICM, CNRS UMR7225-INSERM U1127-Sorbonne University Hôpital de La Pitié-Salpêtrière, 47 Bd de l'Hôpital, 75013, Paris, France
| | - Gaëlle Fontaine
- Paris Brain Institute, ICM, CNRS UMR7225-INSERM U1127-Sorbonne University Hôpital de La Pitié-Salpêtrière, 47 Bd de l'Hôpital, 75013, Paris, France
| | - Eleni Gkanatsiou
- Department of Psychiatry and Neurochemistry, Institute of Neuroscience & Physiology, the Sahlgrenska Academy at the University of Gothenburg, Mölndal, S-431 80, Sweden
| | - Gunnar Brinkmalm
- Department of Psychiatry and Neurochemistry, Institute of Neuroscience & Physiology, the Sahlgrenska Academy at the University of Gothenburg, Mölndal, S-431 80, Sweden
| | - Elena Camporesi
- Department of Psychiatry and Neurochemistry, Institute of Neuroscience & Physiology, the Sahlgrenska Academy at the University of Gothenburg, Mölndal, S-431 80, Sweden
| | - Erik Portelius
- Department of Psychiatry and Neurochemistry, Institute of Neuroscience & Physiology, the Sahlgrenska Academy at the University of Gothenburg, Mölndal, S-431 80, Sweden
- Clinical Neurochemistry Laboratory, Sahlgrenska University Hospital, S-431 80, Mölndal, Sweden
| | - Kaj Blennow
- Department of Psychiatry and Neurochemistry, Institute of Neuroscience & Physiology, the Sahlgrenska Academy at the University of Gothenburg, Mölndal, S-431 80, Sweden
- Clinical Neurochemistry Laboratory, Sahlgrenska University Hospital, S-431 80, Mölndal, Sweden
| | - Gilles Mourier
- Clinical Neurochemistry Laboratory, Sahlgrenska University Hospital, S-431 80, Mölndal, Sweden
- Département Médicaments Et Technologies Pour La Santé (DMTS), Université Paris Saclay, CEA, INRAE, SIMoS, 91191, Gif-sur-Yvette, France
| | - Nicolas Gilles
- Clinical Neurochemistry Laboratory, Sahlgrenska University Hospital, S-431 80, Mölndal, Sweden
- Département Médicaments Et Technologies Pour La Santé (DMTS), Université Paris Saclay, CEA, INRAE, SIMoS, 91191, Gif-sur-Yvette, France
| | - Mark J Millan
- Neuroscience Inflammation Thérapeutic Area, IDR Servier, 125 Chemin de Ronde, 78290, Croissy-sur-Seine, France
- Institute of Neuroscience and Psychology, College of Medicine, Vet and Life Sciences, Glasgow University, 62 Hillhead Street, Glasgow, G12 8QB, Scotland
| | - Catherine Marquer
- Paris Brain Institute, ICM, CNRS UMR7225-INSERM U1127-Sorbonne University Hôpital de La Pitié-Salpêtrière, 47 Bd de l'Hôpital, 75013, Paris, France
| | - Henrik Zetterberg
- Department of Psychiatry and Neurochemistry, Institute of Neuroscience & Physiology, the Sahlgrenska Academy at the University of Gothenburg, Mölndal, S-431 80, Sweden
- Clinical Neurochemistry Laboratory, Sahlgrenska University Hospital, S-431 80, Mölndal, Sweden
- Department of Neurodegenerative Disease, UCL Institute of Neurology, London, WC1N 3BG, UK
- UK Dementia Research Institute at UCL, London, WC1E 6BT, UK
| | - Lydie Boussicault
- Paris Brain Institute, ICM, CNRS UMR7225-INSERM U1127-Sorbonne University Hôpital de La Pitié-Salpêtrière, 47 Bd de l'Hôpital, 75013, Paris, France
| | - Marie-Claude Potier
- Paris Brain Institute, ICM, CNRS UMR7225-INSERM U1127-Sorbonne University Hôpital de La Pitié-Salpêtrière, 47 Bd de l'Hôpital, 75013, Paris, France.
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9
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A Historical Review of Brain Drug Delivery. Pharmaceutics 2022; 14:pharmaceutics14061283. [PMID: 35745855 PMCID: PMC9229021 DOI: 10.3390/pharmaceutics14061283] [Citation(s) in RCA: 49] [Impact Index Per Article: 24.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Revised: 06/01/2022] [Accepted: 06/07/2022] [Indexed: 12/13/2022] Open
Abstract
The history of brain drug delivery is reviewed beginning with the first demonstration, in 1914, that a drug for syphilis, salvarsan, did not enter the brain, due to the presence of a blood-brain barrier (BBB). Owing to restricted transport across the BBB, FDA-approved drugs for the CNS have been generally limited to lipid-soluble small molecules. Drugs that do not cross the BBB can be re-engineered for transport on endogenous BBB carrier-mediated transport and receptor-mediated transport systems, which were identified during the 1970s-1980s. By the 1990s, a multitude of brain drug delivery technologies emerged, including trans-cranial delivery, CSF delivery, BBB disruption, lipid carriers, prodrugs, stem cells, exosomes, nanoparticles, gene therapy, and biologics. The advantages and limitations of each of these brain drug delivery technologies are critically reviewed.
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10
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Nelson AR. Peripheral Pathways to Neurovascular Unit Dysfunction, Cognitive Impairment, and Alzheimer’s Disease. Front Aging Neurosci 2022; 14:858429. [PMID: 35517047 PMCID: PMC9062225 DOI: 10.3389/fnagi.2022.858429] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2022] [Accepted: 03/03/2022] [Indexed: 12/11/2022] Open
Abstract
Alzheimer’s disease (AD) is the most common form of dementia. It was first described more than a century ago, and scientists are acquiring new data and learning novel information about the disease every day. Although there are nuances and details continuously being unraveled, many key players were identified in the early 1900’s by Dr. Oskar Fischer and Dr. Alois Alzheimer, including amyloid-beta (Aβ), tau, vascular abnormalities, gliosis, and a possible role of infections. More recently, there has been growing interest in and appreciation for neurovascular unit dysfunction that occurs early in mild cognitive impairment (MCI) before and independent of Aβ and tau brain accumulation. In the last decade, evidence that Aβ and tau oligomers are antimicrobial peptides generated in response to infection has expanded our knowledge and challenged preconceived notions. The concept that pathogenic germs cause infections generating an innate immune response (e.g., Aβ and tau produced by peripheral organs) that is associated with incident dementia is worthwhile considering in the context of sporadic AD with an unknown root cause. Therefore, the peripheral amyloid hypothesis to cognitive impairment and AD is proposed and remains to be vetted by future research. Meanwhile, humans remain complex variable organisms with individual risk factors that define their immune status, neurovascular function, and neuronal plasticity. In this focused review, the idea that infections and organ dysfunction contribute to Alzheimer’s disease, through the generation of peripheral amyloids and/or neurovascular unit dysfunction will be explored and discussed. Ultimately, many questions remain to be answered and critical areas of future exploration are highlighted.
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11
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Capillary function progressively deteriorates in prodromal Alzheimer's disease: A longitudinal MRI perfusion study. AGING BRAIN 2022; 2:100035. [PMID: 36908896 PMCID: PMC9997144 DOI: 10.1016/j.nbas.2022.100035] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2021] [Revised: 02/02/2022] [Accepted: 02/04/2022] [Indexed: 11/20/2022] Open
Abstract
Cardiovascular risk factors are associated with the development of Alzheimer's disease (AD), and increasing evidence suggests that cerebral microvascular dysfunction plays a vital role in the disease progression. Using magnetic resonance imaging, we investigated the two-year changes of the cerebral microvascular blood flow in 11 mild cognitively impaired (MCI) patients with prodromal AD compared to 12 MCI patients without evidence of AD and 10 cognitively intact age-matched controls. The pAD-MCI patients displayed widespread deterioration in microvascular cerebral perfusion associated with capillary dysfunction. No such changes were observed in the other two groups, suggesting that the dysfunction in capillary perfusion is linked to the AD pathophysiology. The observed capillary dysfunction may limit local oxygenation in AD leading to downstream β-amyloid aggregation, tau hyperphosphorylation, neuroinflammation and neuronal dysfunction. The findings are in agreement with the capillary dysfunction hypothesis of AD, suggesting that increasing heterogeneity of capillary blood flow is a primary pathological event in AD.
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12
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Ojo J, Eisenbaum M, Shackleton B, Lynch C, Joshi U, Saltiel N, Pearson A, Ringland C, Paris D, Mouzon B, Mullan M, Crawford F, Bachmeier C. Mural cell dysfunction leads to altered cerebrovascular tau uptake following repetitive head trauma. Neurobiol Dis 2020; 150:105237. [PMID: 33383188 PMCID: PMC8170787 DOI: 10.1016/j.nbd.2020.105237] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Revised: 12/07/2020] [Accepted: 12/26/2020] [Indexed: 12/29/2022] Open
Abstract
A pathological characteristic of repetitive traumatic brain injury (TBI) is the deposition of hyperphosphorylated and aggregated tau species in the brain and increased levels of extracellular monomeric tau are believed to play a role in the pathogenesis of neurodegenerative tauopathies. The pathways by which extracellular tau is eliminated from the brain, however, remains elusive. The purpose of this study was to examine tau uptake by cerebrovascular cells and the effect of TBI on these processes. We found monomeric tau interacts with brain vascular mural cells (pericytes and smooth muscle cells) to a greater extent than other cerebrovascular cells, indicating mural cells may contribute to the elimination of extracellular tau, as previously described for other solutes such as beta-amyloid. Consistent with other neurodegenerative disorders, we observed a progressive decline in cerebrovascular mural cell markers up to 12 months post-injury in a mouse model of repetitive mild TBI (r-mTBI) and human TBI brain specimens, when compared to control. These changes appear to reflect mural cell degeneration and not cellular loss as no difference in the mural cell population was observed between r-mTBI and r-sham animals as determined through flow cytometry. Moreover, freshly isolated r-mTBI cerebrovessels showed reduced tau uptake at 6 and 12 months post-injury compared to r-sham animals, which may be the result of diminished cerebrovascular endocytosis, as caveolin-1 levels were significantly decreased in mouse r-mTBI and human TBI cerebrovessels compared to their respective controls. Further emphasizing the interaction between mural cells and tau, similar reductions in mural cell markers, tau uptake, and caveolin-1 were observed in cerebrovessels from transgenic mural cell-depleted animals. In conclusion, our studies indicate repeated injuries to the brain causes chronic mural cell degeneration, reducing the caveolar-mediated uptake of tau by these cells. Alterations in tau uptake by vascular mural cells may contribute to tau deposition in the brain following head trauma and could represent a novel therapeutic target for TBI or other neurodegenerative disorders.
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Affiliation(s)
- Joseph Ojo
- The Roskamp Institute, Sarasota, FL, USA; The Open University, Milton Keynes, UK
| | - Max Eisenbaum
- The Roskamp Institute, Sarasota, FL, USA; The Open University, Milton Keynes, UK
| | - Ben Shackleton
- The Roskamp Institute, Sarasota, FL, USA; The Open University, Milton Keynes, UK
| | - Cillian Lynch
- The Roskamp Institute, Sarasota, FL, USA; The Open University, Milton Keynes, UK
| | - Utsav Joshi
- The Roskamp Institute, Sarasota, FL, USA; The Open University, Milton Keynes, UK
| | | | - Andrew Pearson
- The Roskamp Institute, Sarasota, FL, USA; The Open University, Milton Keynes, UK
| | - Charis Ringland
- The Roskamp Institute, Sarasota, FL, USA; The Open University, Milton Keynes, UK
| | - Daniel Paris
- The Roskamp Institute, Sarasota, FL, USA; The Open University, Milton Keynes, UK
| | - Benoit Mouzon
- The Roskamp Institute, Sarasota, FL, USA; The Open University, Milton Keynes, UK
| | - Michael Mullan
- The Roskamp Institute, Sarasota, FL, USA; The Open University, Milton Keynes, UK
| | - Fiona Crawford
- The Roskamp Institute, Sarasota, FL, USA; The Open University, Milton Keynes, UK; James A. Haley Veterans' Hospital, Tampa, FL, USA
| | - Corbin Bachmeier
- The Roskamp Institute, Sarasota, FL, USA; The Open University, Milton Keynes, UK; Bay Pines VA Healthcare System, Bay Pines, FL, USA.
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13
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Pardridge WM. Treatment of Alzheimer's Disease and Blood-Brain Barrier Drug Delivery. Pharmaceuticals (Basel) 2020; 13:E394. [PMID: 33207605 PMCID: PMC7697739 DOI: 10.3390/ph13110394] [Citation(s) in RCA: 84] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2020] [Revised: 11/12/2020] [Accepted: 11/13/2020] [Indexed: 12/12/2022] Open
Abstract
Despite the enormity of the societal and health burdens caused by Alzheimer's disease (AD), there have been no FDA approvals for new therapeutics for AD since 2003. This profound lack of progress in treatment of AD is due to dual problems, both related to the blood-brain barrier (BBB). First, 98% of small molecule drugs do not cross the BBB, and ~100% of biologic drugs do not cross the BBB, so BBB drug delivery technology is needed in AD drug development. Second, the pharmaceutical industry has not developed BBB drug delivery technology, which would enable industry to invent new therapeutics for AD that actually penetrate into brain parenchyma from blood. In 2020, less than 1% of all AD drug development projects use a BBB drug delivery technology. The pathogenesis of AD involves chronic neuro-inflammation, the progressive deposition of insoluble amyloid-beta or tau aggregates, and neural degeneration. New drugs that both attack these multiple sites in AD, and that have been coupled with BBB drug delivery technology, can lead to new and effective treatments of this serious disorder.
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Affiliation(s)
- William M Pardridge
- Department of Medicine, University of California, Los Angeles, CA 90024, USA
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14
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Kirabali T, Rust R, Rigotti S, Siccoli A, Nitsch RM, Kulic L. Distinct changes in all major components of the neurovascular unit across different neuropathological stages of Alzheimer's disease. Brain Pathol 2020; 30:1056-1070. [PMID: 32866303 PMCID: PMC8018068 DOI: 10.1111/bpa.12895] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
In the brain capillaries, endothelial cells, pericytes, astrocytes and microglia form a structural and functional complex called neurovascular unit (NVU) which is critically involved in maintaining neuronal homeostasis. In the present study, we applied a comprehensive immunohistochemical approach to investigate the structural alterations in the NVU across different Alzheimer's disease (AD) neuropathological stages. Post-mortem human cortical and hippocampal samples derived from AD patients and non-demented elderly control individuals were immunostained using a panel of markers representing specific components of the NVU including Collagen IV (basement membrane), PDGFR-β (pericytes), GFAP (astrocytes), Iba1 (microglia), MRC1 (perivascular macrophages) and lectin as an endothelial cell label. Astrocytes (GFAP) and microglia (Iba1) were quantified both in the whole visual-field and specifically within the NVU, and the sample set was additionally analyzed using anti-tau (AT8) and three different anti-Aβ (clones G2-10, G2-11, 4G8) antibodies. Analyses of lectin labeled sections showed an altered vascular distribution in AD patients as revealed by a reduced nearest distance between capillaries. Within the NVU, a Braak-stage dependent reduction in pericyte coverage was identified as the earliest structural alteration during AD progression. In comparison to non-demented elderly controls, AD patients showed a significantly higher astrocyte coverage within the NVU, which was paralleled by a reduced microglial coverage around capillaries. Assessment of perivascular macrophages moreover demonstrated a relocation of these cells from leptomeningeal arteries to penetrating parenchymal vessels in AD patients. Collectively, the results of our study represent a comprehensive first in-depth analysis of AD-related structural changes in the NVU and suggest distinct alterations in all components of the NVU during AD progression.
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Affiliation(s)
- Tunahan Kirabali
- Institute for Regenerative MedicineUniversity of ZurichSchlierenSwitzerland
| | - Ruslan Rust
- Institute for Regenerative MedicineUniversity of ZurichSchlierenSwitzerland
| | - Serena Rigotti
- Institute for Regenerative MedicineUniversity of ZurichSchlierenSwitzerland
- Department of BiologyETH ZurichZurichSwitzerland
| | - Alessandro Siccoli
- Institute for Regenerative MedicineUniversity of ZurichSchlierenSwitzerland
- Faculty of MedicineUniversity Hospital ZurichZürichSwitzerland
| | - Roger M. Nitsch
- Institute for Regenerative MedicineUniversity of ZurichSchlierenSwitzerland
- NeurimmuneSchlierenSwitzerland
| | - Luka Kulic
- Institute for Regenerative MedicineUniversity of ZurichSchlierenSwitzerland
- Roche Pharma Research & Early DevelopmentF. Hoffmann‐La Roche Ltd.BaselSwitzerland
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15
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Jeske R, Albo J, Marzano M, Bejoy J, Li Y. Engineering Brain-Specific Pericytes from Human Pluripotent Stem Cells. TISSUE ENGINEERING. PART B, REVIEWS 2020; 26:367-382. [PMID: 32571167 PMCID: PMC7462039 DOI: 10.1089/ten.teb.2020.0091] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2020] [Accepted: 06/19/2020] [Indexed: 02/06/2023]
Abstract
Pericytes (PCs) are a type of perivascular cells that surround endothelial cells of small blood vessels. In the brain, PCs show heterogeneity depending on their position within the vasculature. As a result, PC interactions with surrounding endothelial cells, astrocytes, and neuron cells play a key role in a wide array of neurovascular functions such as regulating blood-brain barrier (BBB) permeability, cerebral blood flow, and helping to facilitate the clearance of toxic cellular molecules. Therefore, a reliable method of engineering brain-specific PCs from human induced pluripotent stem cells (hiPSCs) is critical in neurodegenerative disease modeling. This review summarizes brain-specific PC differentiation of hiPSCs through mesoderm and neural crest induction. Key signaling pathways (platelet-derived growth factor-B [PDGF-B], transforming growth factor [TGF]-β, and Notch signaling) regulating PC function, PC interactions with adjacent cells, and PC differentiation from hiPSCs are also discussed. Specifically, PDGF-BB-platelet-derived growth factor receptor β signaling promotes PC cell survival, TGF-β signal transduction facilitates PC attachment to endothelial cells, and Notch signaling is critical in vascular development and arterial-venous specification. Furthermore, current challenges facing the use of hiPSC-derived PCs are discussed, and their ongoing uses in neurodegenerative disease modeling are identified. Further investigations into PCs and surrounding cell interactions are needed to characterize the roles of brain PCs in various neurodegenerative disorders. Impact statement This article summarizes the work related to brain-specific pericytes (PCs) derived from human pluripotent stem cells (hPSCs). In particular, key signaling pathways regulating PC function, PC interactions with adjacent cells, and PC differentiation from hPSCs were discussed. Furthermore, current challenges facing the use of hPSC-derived PCs were identified, and their ongoing uses in neurodegenerative disease modeling were discussed. The review highlights the important role of cell-cell interactions in blood-brain barrier (BBB) models and neurodegeneration. The summarized findings are significant for establishing pluripotent stem cell-based BBB models toward the applications in drug screening and disease modeling.
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Affiliation(s)
- Richard Jeske
- Department of Chemical and Biomedical Engineering, FAMU-FSU College of Engineering, Florida State University, Tallahassee, Florida, USA
| | - Jonathan Albo
- Department of Chemical and Biomedical Engineering, FAMU-FSU College of Engineering, Florida State University, Tallahassee, Florida, USA
| | - Mark Marzano
- Department of Chemical and Biomedical Engineering, FAMU-FSU College of Engineering, Florida State University, Tallahassee, Florida, USA
| | - Julie Bejoy
- Department of Chemical and Biomedical Engineering, FAMU-FSU College of Engineering, Florida State University, Tallahassee, Florida, USA
| | - Yan Li
- Department of Chemical and Biomedical Engineering, FAMU-FSU College of Engineering, Florida State University, Tallahassee, Florida, USA
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16
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Interactions between Amyloid-Β Proteins and Human Brain Pericytes: Implications for the Pathobiology of Alzheimer's Disease. J Clin Med 2020; 9:jcm9051490. [PMID: 32429102 PMCID: PMC7290583 DOI: 10.3390/jcm9051490] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2020] [Revised: 05/08/2020] [Accepted: 05/12/2020] [Indexed: 02/06/2023] Open
Abstract
Alzheimer’s disease (AD) is a progressive neurodegenerative disease that is the most common cause of dementia, especially among aging populations. Despite advances in AD research, the underlying cause and the discovery of disease-modifying treatments have remained elusive. Two key features of AD pathology are the aberrant deposition of amyloid beta (amyloid-β or Aβ) proteins in the brain parenchyma and Aβ toxicity in brain pericytes of the neurovascular unit/blood–brain barrier (NVU/BBB). This toxicity induces oxidative stress in pericytes and leads to capillary constriction. The interaction between pericytes and Aβ proteins results in the release of endothelin-1 in the pericytes. Endothelin-1 interacts with ETA receptors to cause pericyte contraction. This pericyte-mediated constriction of brain capillaries can cause chronic hypoperfusion of the brain microvasculature, subsequently leading to the neurodegeneration and cognitive decline observed in AD patients. The interaction between Aβ proteins and brain pericytes is largely unknown and requires further investigation. This review provides an updated overview of the interaction between Aβ proteins with pericytes, one the most significant and often forgotten cellular components of the BBB and the inner blood–retinal barrier (IBRB). The IBRB has been shown to be a window into the central nervous system (CNS) that could allow the early diagnosis of AD pathology in the brain and the BBB using modern photonic imaging systems such as optical coherence tomography (OCT) and two-photon microscopy. In this review, I explore the regulation of Aβ proteins in the brain parenchyma, their role in AD pathobiology, and their association with pericyte function. This review discusses Aβ proteins and pericytes in the ocular compartment of AD patients as well as strategies to rescue or protect pericytes from the effects of Aβ proteins, or to replace them with healthy cells.
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17
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Pardridge WM. The Isolated Brain Microvessel: A Versatile Experimental Model of the Blood-Brain Barrier. Front Physiol 2020; 11:398. [PMID: 32457645 PMCID: PMC7221163 DOI: 10.3389/fphys.2020.00398] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2020] [Accepted: 04/02/2020] [Indexed: 12/12/2022] Open
Abstract
A versatile experimental model for the investigation of the blood-brain barrier (BBB), including the neuro-vascular unit, is the isolated brain microvessel preparation. Brain microvessels are primarily comprised of endothelial cells, but also include pericytes, pre-capillary arteriolar smooth muscle cells, astrocyte foot processes, and occasional nerve endings. These microvessels can be isolated from brain with a 3 h procedure, and the microvessels are free of brain parenchyma. Brain microvessels have been isolated from fresh animal brain, fresh human brain obtained at neurosurgery, as well as fresh or frozen autopsy human brain. Brain microvessels are the starting point for isolation of brain microvessel RNA, which then enables the production of BBB cDNA libraries and a genomics analysis of the brain microvasculature. Brain microvessels, combined with quantitative targeted absolute proteomics, allow for the quantitation of specific transporters or receptors expressed at the brain microvasculature. Brain microvessels, combined with specific antibodies and immune labeling of isolated capillaries, allow for the cellular location of proteins expressed within the neuro-vascular unit. Isolated brain microvessels can be used as an “in vitro” preparation of the BBB for the study of the kinetic parameters of BBB carrier-mediated transport (CMT) systems, or for the determination of dissociation constants of peptide binding to BBB receptor-mediated transport (RMT) systems expressed at either the animal or the human BBB. This review will discuss how the isolated brain microvessel model system has advanced our understanding of the organization and functional properties of the BBB, and highlight recent renewed interest in this 50 year old model of the BBB.
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Affiliation(s)
- William M Pardridge
- Department of Medicine, University of California, Los Angeles, Los Angeles, CA, United States
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