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Zhang X, O’Callaghan P, Li H, Tan Y, Zhang G, Barash U, Wang X, Lannfelt L, Vlodavsky I, Lindahl U, Li JP. Heparanase overexpression impedes perivascular clearance of amyloid-β from murine brain: relevance to Alzheimer's disease. Acta Neuropathol Commun 2021; 9:84. [PMID: 33971986 PMCID: PMC8111754 DOI: 10.1186/s40478-021-01182-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2021] [Accepted: 04/14/2021] [Indexed: 12/23/2022] Open
Abstract
Defective amyloid-β (Aβ) clearance from the brain is a major contributing factor to the pathophysiology of Alzheimer's disease (AD). Aβ clearance is mediated by macrophages, enzymatic degradation, perivascular drainage along the vascular basement membrane (VBM) and transcytosis across the blood-brain barrier (BBB). AD pathology is typically associated with cerebral amyloid angiopathy due to perivascular accumulation of Aβ. Heparan sulfate (HS) is an important component of the VBM, thought to fulfill multiple roles in AD pathology. We previously showed that macrophage-mediated clearance of intracortically injected Aβ was impaired in the brains of transgenic mice overexpressing heparanase (Hpa-tg). This study revealed that perivascular drainage was impeded in the Hpa-tg brain, evidenced by perivascular accumulation of the injected Aβ in the thalamus of Hpa-tg mice. Furthermore, endogenous Aβ accumulated at the perivasculature of Hpa-tg thalamus, but not in control thalamus. This perivascular clearance defect was confirmed following intracortical injection of dextran that was largely retained in the perivasculature of Hpa-tg brains, compared to control brains. Hpa-tg brains presented with thicker VBMs and swollen perivascular astrocyte endfeet, as well as elevated expression of the BBB-associated water-pump protein aquaporin 4 (AQP4). Elevated levels of both heparanase and AQP4 were also detected in human AD brain. These findings indicate that elevated heparanase levels alter the organization and composition of the BBB, likely through increased fragmentation of BBB-associated HS, resulting in defective perivascular drainage. This defect contributes to perivascular accumulation of Aβ in the Hpa-tg brain, highlighting a potential role for heparanase in the pathogenesis of AD.
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Rosu GC, Catalin B, Balseanu TA, Laurentiu M, Claudiu M, Kumar-Singh S, Daniel P. Inhibition of Aquaporin 4 Decreases Amyloid Aβ40 Drainage Around Cerebral Vessels. Mol Neurobiol 2020; 57:4720-34. [PMID: 32783141 DOI: 10.1007/s12035-020-02044-8] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Accepted: 07/24/2020] [Indexed: 01/17/2023]
Abstract
Aquaporin-4 (AQP4) is located mainly in the astrocytic end-feet around cerebral blood vessels and regulates ion and water homeostasis in the brain. While deletion of AQP4 is shown to reduce amyloid-β (Aβ) clearance and exacerbate Aβ peptide accumulation in plaques and vessels of Alzheimer's disease mouse models, the mechanism and clearing pathways involved are debated. Here, we investigated how inhibiting the function of AQP4 in healthy male C57BL/6 J mice impacts clearance of Aβ40, the more soluble Aβ isoform. Using two-photon in vivo imaging and visualizing vessels with Sulfurodamine 101 (SR101), we first showed that Aβ40 injected as a ≤ 0.5-μl volume in the cerebral cortex diffused rapidly in parenchyma and accumulated around blood vessels. In animals treated with the AQP4 inhibitor TGN-020, the perivascular Aβ40 accumulation was significantly (P < 0.001) intensified by involving four times more vessels, thus suggesting a generalized clearance defect associated with vessels. Increasing the injecting volume to ≥ 0.5 ≤ 1 μl decreased the difference of Aβ40-positive vessels observed in non-treated and AQP4 inhibitor-treated animals, although the difference was still significant (P = 0.001), suggesting that larger injection volumes could overwhelm intramural vascular clearance mechanisms. While both small and large vessels accumulated Aβ40, for the ≤ 0.5-μl volume group, the average diameter of the Aβ40-positive vessels tended to be larger in control animals compared with TGN-020-treated animals, although the difference was non-significant (P = 0.066). Using histopathology and ultrastructural microscopy, no vascular structural change was observed after a single massive dose of TGN-020. These data suggest that AQP4 deficiency is directly involved in impaired Aβ brain clearance via the peri-/para-vascular routes, and AQP4-mediated vascular clearance might counteract blood-brain barrier abnormalities and age-related vascular amyloidopathy.
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Matsuo K, Shindo A, Niwa A, Tabei KI, Akatsu H, Hashizume Y, Akiyama H, Ayaki T, Maki T, Sawamoto N, Takahashi R, Oikawa S, Tomimoto H. Complement Activation in Capillary Cerebral Amyloid Angiopathy. Dement Geriatr Cogn Disord 2018; 44:343-353. [PMID: 29421784 DOI: 10.1159/000486091] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/15/2017] [Accepted: 11/30/2017] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND Cerebral amyloid angiopathy (CAA) is classified as type 1 with capillary amyloid β (Aβ) or type 2 without capillary Aβ. While it is known that CAA activates complement, an inflammatory mediator, there is no information on the relationship between capillary Aβ and complement activation. METHODS We evaluated 34 autopsy brains, including 22 with CAA and 12 with other neurodegenerative diseases. We assessed the vascular density of CAA by analyzing the expression of complement (C1q, C3d, C6, C5b-9), macrophage scavenger receptor (MSR), and apolipoprotein E (ApoE). RESULTS Capillary immunostaining for C1q, C3d, MSR, and ApoE was identified almost exclusively in CAA-type1 brains. There was intense expression of C1q, C3d, MSR, and ApoE, as well as weaker expression of C5b-9 and C6 in the arteries/ arterioles of both CAA subtypes, but not in control brains. C5b-9 and C6 were preferentially expressed in arteries/arterioles with subcortical hemorrhage or cortical superficial siderosis. Triple immunofluorescence revealed that C1q, C3d, and ApoE were colocalized with Aβ in CAA brain capillaries. CONCLUSION Complement, MSR, and ApoE were only coexpressed in the presence of Aβ accumulation in capillaries, suggesting a role for complement activation in the propagation of Aβ. Additionally, C5b-9 expression may be associated with hemorrhagic brain injury in CAA.
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Affiliation(s)
- Ko Matsuo
- Department of Neurology, Mie University Graduate School of Medicine, Tsu, Japan
| | - Akihiro Shindo
- Department of Neurology, Mie University Graduate School of Medicine, Tsu, Japan
| | - Atsushi Niwa
- Department of Neurology, Mie University Graduate School of Medicine, Tsu, Japan
| | - Ken-Ichi Tabei
- Department of Dementia Prevention and Therapeutics, Mie University Graduate School of Medicine, Tsu, Japan
| | - Hiroyasu Akatsu
- Choju Medical Institute, Fukushimura Hospital, Toyohashi, Japan
| | | | - Haruhiko Akiyama
- Department of Clinical Research, Yokohama Brain and Spine Center, Yokohama, Japan
| | - Takashi Ayaki
- Department of Neurology, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Takakuni Maki
- Department of Neurology, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Nobukatsu Sawamoto
- Department of Neurology, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Ryosuke Takahashi
- Department of Neurology, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Shinji Oikawa
- Department of Environmental and Molecular Medicine, Mie University Graduate School of Medicine, Tsu, Japan
| | - Hidekazu Tomimoto
- Department of Neurology, Mie University Graduate School of Medicine, Tsu, Japan
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Cai K, Tain R, Das S, Damen FC, Sui Y, Valyi-Nagy T, Elliott MA, Zhou XJ. The feasibility of quantitative MRI of perivascular spaces at 7T. J Neurosci Methods 2015; 256:151-6. [PMID: 26358620 DOI: 10.1016/j.jneumeth.2015.09.001] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2015] [Revised: 08/05/2015] [Accepted: 09/01/2015] [Indexed: 01/05/2023]
Abstract
BACKGROUND Dilated brain perivascular spaces (PVSs) are found to be associated with many conditions, including aging, dementia, and Alzheimer's disease (AD). Conventionally, PVS assessment is mainly based on subjective observations of the number, size and shape of PVSs in MR images collected at clinical field strengths (≤3T). This study tests the feasibility of imaging and quantifying brain PVS with an ultra-high 7T whole-body MRI scanner. NEW METHOD 3D high resolution T2-weighted brain images from healthy subjects (n=3) and AD patients (n=5) were acquired on a 7T whole-body MRI scanner. To automatically segment the small hyperintensive fluid-filling PVS structures, we also developed a quantitative program based on algorithms for spatial gradient, component connectivity, edge-detection, k-means clustering, etc., producing quantitative results of white matter PVS volume densities. RESULTS The 3D maps of automatically segmented PVS show an apparent increase in PVS density in AD patients compared to age-matched healthy controls due to the PVS dilation (8.0±2.1 v/v% in AD vs. 4.9±1.3 v/v% in controls, p<0.05). COMPARISON WITH EXISTING METHOD We demonstrated that 7T provides sufficient SNR and resolution for quantitatively measuring PVSs in deep white matter that is challenging with clinical MRI systems (≤3T). Compared to the conventional visual counting and rating for the PVS assessment, the quantitation method we developed is automatic and objective. CONCLUSIONS Quantitative PVS MRI at 7T may serve as a non-invasive and endogenous imaging biomarker for diseases with PVS dilation.
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Affiliation(s)
- Kejia Cai
- Department of Radiology, College of Medicine, University of Illinois at Chicago, Chicago, IL, USA; Center for MR Research, College of Medicine, University of Illinois at Chicago, Chicago, IL, USA.
| | - Rongwen Tain
- Department of Radiology, College of Medicine, University of Illinois at Chicago, Chicago, IL, USA; Center for MR Research, College of Medicine, University of Illinois at Chicago, Chicago, IL, USA
| | - Sandhitsu Das
- Department of Radiology, School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Frederick C Damen
- Department of Radiology, College of Medicine, University of Illinois at Chicago, Chicago, IL, USA; Center for MR Research, College of Medicine, University of Illinois at Chicago, Chicago, IL, USA
| | - Yi Sui
- Center for MR Research, College of Medicine, University of Illinois at Chicago, Chicago, IL, USA; Department of Bioengineering, University of Illinois at Chicago, Chicago, IL, USA
| | - Tibor Valyi-Nagy
- Department of Neuropathology, College of Medicine, University of Illinois at Chicago, Chicago, IL, USA
| | - Mark A Elliott
- Department of Radiology, School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Xiaohong J Zhou
- Department of Radiology, College of Medicine, University of Illinois at Chicago, Chicago, IL, USA; Center for MR Research, College of Medicine, University of Illinois at Chicago, Chicago, IL, USA
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Keable A, Fenna K, Yuen HM, Johnston DA, Smyth NR, Smith C, Al-Shahi Salman R, Samarasekera N, Nicoll JAR, Attems J, Kalaria RN, Weller RO, Carare RO. Deposition of amyloid β in the walls of human leptomeningeal arteries in relation to perivascular drainage pathways in cerebral amyloid angiopathy. Biochim Biophys Acta Mol Basis Dis 2015; 1862:1037-46. [PMID: 26327684 PMCID: PMC4827375 DOI: 10.1016/j.bbadis.2015.08.024] [Citation(s) in RCA: 103] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2015] [Revised: 08/11/2015] [Accepted: 08/26/2015] [Indexed: 11/20/2022]
Abstract
Deposition of amyloid β (Aβ) in the walls of cerebral arteries as cerebral amyloid angiopathy (CAA) suggests an age-related failure of perivascular drainage of soluble Aβ from the brain. As CAA is associated with Alzheimer's disease and with intracerebral haemorrhage, the present study determines the unique sequence of changes that occur as Aβ accumulates in artery walls. Paraffin sections of post-mortem human occipital cortex were immunostained for collagen IV, fibronectin, nidogen 2, Aβ and smooth muscle actin and the immunostaining was analysed using Image J and confocal microscopy. Results showed that nidogen 2 (entactin) increases with age and decreases in CAA. Confocal microscopy revealed stages in the progression of CAA: Aβ initially deposits in basement membranes in the tunica media, replaces first the smooth muscle cells and then the connective tissue elements to leave artery walls completely or focally replaced by Aβ. The pattern of development of CAA in the human brain suggests expansion of Aβ from the basement membranes to progressively replace all tissue elements in the artery wall. Establishing this full picture of the development of CAA is pivotal in understanding the clinical presentation of CAA and for developing therapies to prevent accumulation of Aβ in artery walls. This article is part of a Special Issue entitled: Vascular Contributions to Cognitive Impairment and Dementia edited by M. Paul Murphy, Roderick A. Corriveau and Donna M. Wilcock. Lymphatic drainage of the brain is along basement membranes in the walls of arteries. Perivascular lymphatic drainage fails with age and arteriosclerosis. Aβ deposits in the perivascular drainage pathways of leptomeningeal arteries as CAA. As CAA progresses, Aβ replaces all elements of the ageing artery wall. Facilitation of perivascular drainage may prevent CAA and delay Alzheimer's disease.
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Affiliation(s)
- Abby Keable
- Faculty of Medicine, University of Southampton, Tremona Road, SO16 6YD, UK
| | - Kate Fenna
- Faculty of Medicine, University of Southampton, Tremona Road, SO16 6YD, UK
| | - Ho Ming Yuen
- Faculty of Medicine, University of Southampton, Tremona Road, SO16 6YD, UK
| | - David A Johnston
- Faculty of Medicine, University of Southampton, Tremona Road, SO16 6YD, UK
| | - Neil R Smyth
- Faculty of Medicine, University of Southampton, Tremona Road, SO16 6YD, UK
| | - Colin Smith
- Centre for Clinical Brain Sciences, University of Edinburgh, UK
| | | | | | - James A R Nicoll
- Faculty of Medicine, University of Southampton, Tremona Road, SO16 6YD, UK
| | - Johannes Attems
- Institute of Neuroscience, Campus for Ageing and Vitality, Newcastle University, UK
| | - Rajesh N Kalaria
- Institute of Neuroscience, Campus for Ageing and Vitality, Newcastle University, UK
| | - Roy O Weller
- Faculty of Medicine, University of Southampton, Tremona Road, SO16 6YD, UK
| | - Roxana O Carare
- Faculty of Medicine, University of Southampton, Tremona Road, SO16 6YD, UK.
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