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Shindo A, Liang AC, Maki T, Miyamoto N, Tomimoto H, Lo EH, Arai K. Subcortical ischemic vascular disease: Roles of oligodendrocyte function in experimental models of subcortical white-matter injury. J Cereb Blood Flow Metab 2016; 36:187-98. [PMID: 25920960 PMCID: PMC4758561 DOI: 10.1038/jcbfm.2015.80] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/15/2015] [Revised: 03/30/2015] [Accepted: 03/31/2015] [Indexed: 12/25/2022]
Abstract
Oligodendrocytes are one of the major cell types in cerebral white matter. Under normal conditions, they form myelin sheaths that encircle axons to support fast nerve conduction. Under conditions of cerebral ischemia, oligodendrocytes tend to die, resulting in white-matter dysfunction. Repair of white matter involves the ability of oligodendrocyte precursors to proliferate and mature. However, replacement of lost oligodendrocytes may not be the only mechanism for white-matter recovery. Emerging data now suggest that coordinated signaling between neural, glial, and vascular cells in the entire neurovascular unit may be required. In this mini-review, we discuss how oligodendrocyte lineage cells participate in signaling and crosstalk with other cell types to underlie function and recovery in various experimental models of subcortical white-matter injury.
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Affiliation(s)
- Akihiro Shindo
- Neuroprotection Research Laboratory, Departments of Radiology and Neurology, Massachusetts General Hospital and Harvard Medical School, Charlestown, Massachusetts, USA
- Department of Neurology, Mie University Graduate School of Medicine, Mie, Japan
| | - Anna C Liang
- Neuroprotection Research Laboratory, Departments of Radiology and Neurology, Massachusetts General Hospital and Harvard Medical School, Charlestown, Massachusetts, USA
| | - Takakuni Maki
- Neuroprotection Research Laboratory, Departments of Radiology and Neurology, Massachusetts General Hospital and Harvard Medical School, Charlestown, Massachusetts, USA
| | - Nobukazu Miyamoto
- Neuroprotection Research Laboratory, Departments of Radiology and Neurology, Massachusetts General Hospital and Harvard Medical School, Charlestown, Massachusetts, USA
| | - Hidekazu Tomimoto
- Department of Neurology, Mie University Graduate School of Medicine, Mie, Japan
| | - Eng H Lo
- Neuroprotection Research Laboratory, Departments of Radiology and Neurology, Massachusetts General Hospital and Harvard Medical School, Charlestown, Massachusetts, USA
| | - Ken Arai
- Neuroprotection Research Laboratory, Departments of Radiology and Neurology, Massachusetts General Hospital and Harvard Medical School, Charlestown, Massachusetts, USA
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Sfera A, Osorio C, Inderias L, Cummings M. The Ticking of the Epigenetic Clock: Antipsychotic Drugs in Old Age. Front Endocrinol (Lausanne) 2016; 7:122. [PMID: 27630617 PMCID: PMC5005952 DOI: 10.3389/fendo.2016.00122] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/02/2016] [Accepted: 08/23/2016] [Indexed: 11/25/2022] Open
Abstract
BACKGROUND Exposed to antipsychotic drugs (APDs), older individuals with dementing illness are at risk of cerebrovascular adverse effects (CVAE), including sudden death. Transient microvascular dysfunctions are known to occur in younger persons exposed to APDs; however, they seldom progress to CVAE, suggesting that APDs alone are insufficient for engendering this untoward effect. It is, therefore, believed that a preexistent microvascular damage is necessary for CVAE to take place, but the exact nature of this lesion remains unclear. CNS small vessel disease (SVD) is a well-known age-related risk factor for strokes, dementia, and sudden death, which may constitute the initial CVAE-predisposing pathology. Therefore, we propose the two strikes CVAE paradigm, in which SVD represents the first strike, while exposure to APDs, the second. In this model, both strikes must be present for CVAE to take place, and the neuroimaging load of white matter hyperintensities may be directly proportional with the CVAE risk. To investigate this hypothesis at the molecular level, we focused on a seemingly unrelated phenomenon: both APDs and SVD were found protective against a similar repertoire of cancers and their spread to the brain (1-4). Since microRNA-29 has shown efficacy against the same malignancies and has been associated with small vessels pathology, we narrowed our search down to this miR, hypothesizing that the APDs mechanism of action includes miR-29 upregulation, which in turn facilitates the development of SVD. AIM To assess whether miR-29 can be utilized as a peripheral blood biomarker for SVD and CVAE risk. METHOD We conducted a search of experimentally verified miR-29 target genes utilizing the public domain tools miRanda, RNA22 and Weizemann Institute of Science miRNA Analysis. We identified in total 67 experimentally verified target genes for miR-29 family, 18 of which correlate with microvascular integrity and may be relevant for CVAE. CONCLUSION Upregulated microRNA-29 silences the expression of 18 genes connected with capillary stability, engendering a major vulnerability for SVD (first strike) which in turn increases the risk for CVAE after exposure to APDs (second strike).
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Affiliation(s)
- Adonis Sfera
- Psychiatry, Patton State Hospital, Patton, CA, USA
- *Correspondence: Adonis Sfera,
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Mayhan WG, Scott JP, Arrick DM. Influence of type 1 diabetes on basal and agonist-induced permeability of the blood-brain barrier. Physiol Rep 2015; 3:3/12/e12653. [PMID: 26660561 PMCID: PMC4760440 DOI: 10.14814/phy2.12653] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Type 1 diabetes mellitus (T1D) impairs endothelial nitric oxide synthase (eNOS)‐dependent responses of cerebral arterioles. However, the influence of T1D on another critical aspect of endothelial cell function in the cerebral microcirculation, i.e., regulation of permeability of the blood–brain barrier (BBB), remains largely unknown. Our goal was to examine basal and agonist‐induced changes in permeability of the BBB in nondiabetic and type 1 diabetic (streptozotocin; 50 mg/kg IP) rats. On the day of the experiment (2–3 months after streptozotocin), a craniotomy was made over the parietal cortex in nondiabetic and diabetic rats. We measured the permeability of the BBB (FITC‐dextran‐10K) under basal conditions and during application of histamine. We also measured diameter of cerebral arterioles in response to histamine in the absence and presence of NG‐monomethyl‐L‐arginine (L‐NMMA). We found that basal permeability of the BBB was elevated in T1D and application of histamine did not produce a further increase in permeability. In contrast, basal permeability of the BBB was minimal in nondiabetics and histamine produced an increase in permeability. In addition, histamine‐induced arteriolar dilation was less in diabetics than in nondiabetics, and vasodilation to histamine was inhibited by L‐NMMA. Our findings suggest that T1D‐induced endothelial dysfunction leads to an increase in basal permeability of the BBB, but decreases the ability of the endothelium of the BBB to respond to an important inflammatory mediator. Thus, T1D impairs two critical aspects of endothelial cell function in the cerebral microcirculation, i.e., basal and agonist‐induced changes in permeability of the BBB and arteriolar dilation.
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Affiliation(s)
- William G Mayhan
- Department of Cellular Biology and Anatomy, LSU Health Sciences Center-Shreveport, Shreveport, Louisiana
| | - Jasmine P Scott
- Department of Cellular Biology and Anatomy, LSU Health Sciences Center-Shreveport, Shreveport, Louisiana
| | - Denise M Arrick
- Department of Cellular Biology and Anatomy, LSU Health Sciences Center-Shreveport, Shreveport, Louisiana
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Potassium channelopathy-like defect underlies early-stage cerebrovascular dysfunction in a genetic model of small vessel disease. Proc Natl Acad Sci U S A 2015; 112:E796-805. [PMID: 25646445 DOI: 10.1073/pnas.1420765112] [Citation(s) in RCA: 67] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL), caused by dominant mutations in the NOTCH3 receptor in vascular smooth muscle, is a genetic paradigm of small vessel disease (SVD) of the brain. Recent studies using transgenic (Tg)Notch3(R169C) mice, a genetic model of CADASIL, revealed functional defects in cerebral (pial) arteries on the surface of the brain at an early stage of disease progression. Here, using parenchymal arterioles (PAs) from within the brain, we determined the molecular mechanism underlying the early functional deficits associated with this Notch3 mutation. At physiological pressure (40 mmHg), smooth muscle membrane potential depolarization and constriction to pressure (myogenic tone) were blunted in PAs from TgNotch3(R169C) mice. This effect was associated with an ∼ 60% increase in the number of voltage-gated potassium (KV) channels, which oppose pressure-induced depolarization. Inhibition of KV1 channels with 4-aminopyridine (4-AP) or treatment with the epidermal growth factor receptor agonist heparin-binding EGF (HB-EGF), which promotes KV1 channel endocytosis, reduced KV current density and restored myogenic responses in PAs from TgNotch3(R169C) mice, whereas pharmacological inhibition of other major vasodilatory influences had no effect. KV1 currents and myogenic responses were similarly altered in pial arteries from TgNotch3(R169C) mice, but not in mesenteric arteries. Interestingly, HB-EGF had no effect on mesenteric arteries, suggesting a possible mechanistic basis for the exclusive cerebrovascular manifestation of CADASIL. Collectively, our results indicate that increasing the number of KV1 channels in cerebral smooth muscle produces a mutant vascular phenotype akin to a channelopathy in a genetic model of SVD.
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Choi JC. Genetics of cerebral small vessel disease. J Stroke 2015; 17:7-16. [PMID: 25692103 PMCID: PMC4325630 DOI: 10.5853/jos.2015.17.1.7] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2014] [Revised: 12/26/2014] [Accepted: 12/29/2014] [Indexed: 01/23/2023] Open
Abstract
Cerebral small vessel disease (SVD) is an important cause of stroke and cognitive impairment among the elderly and is a more frequent cause of stroke in Asia than in the US or Europe. Although traditional risk factors such as hypertension or diabetes mellitus are important in the development of cerebral SVD, the exact pathogenesis is still uncertain. Both, twin and family history studies suggest heritability of sporadic cerebral SVD, while the candidate gene study and the genome-wide association study (GWAS) are mainly used in genetic research. Robust associations between the candidate genes and occurrence of various features of sporadic cerebral SVD, such as lacunar infarction, intracerebral hemorrhage, or white matter hyperintensities, have not yet been elucidated. GWAS, a relatively new technique, overcomes several shortcomings of previous genetic techniques, enabling the detection of several important genetic loci associated with cerebral SVD. In addition to the more common, sporadic cerebral SVD, several single-gene disorders causing cerebral SVD have been identified. The number of reported cases is increasing as the clinical features become clear and diagnostic examinations are more readily available. These include cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy, cerebral autosomal recessive arteriopathy with subcortical infarcts and leukoencephalopathy, COL4A1-related cerebral SVD, autosomal dominant retinal vasculopathy with cerebral leukodystrophy, and Fabry disease. These rare single-gene disorders are expected to play a crucial role in our understanding of cerebral SVD pathogenesis by providing animal models for the identification of cellular, molecular, and biochemical changes underlying cerebral small vessel damage.
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Affiliation(s)
- Jay Chol Choi
- Department of Neurology, Jeju National University, Jeju, Korea
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Mao M, Alavi MV, Labelle-Dumais C, Gould DB. Type IV Collagens and Basement Membrane Diseases. CURRENT TOPICS IN MEMBRANES 2015; 76:61-116. [DOI: 10.1016/bs.ctm.2015.09.002] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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Beaufort N, Scharrer E, Kremmer E, Lux V, Ehrmann M, Huber R, Houlden H, Werring D, Haffner C, Dichgans M. Cerebral small vessel disease-related protease HtrA1 processes latent TGF-β binding protein 1 and facilitates TGF-β signaling. Proc Natl Acad Sci U S A 2014; 111:16496-501. [PMID: 25369932 PMCID: PMC4246310 DOI: 10.1073/pnas.1418087111] [Citation(s) in RCA: 108] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
High temperature requirement protein A1 (HtrA1) is a primarily secreted serine protease involved in a variety of cellular processes including transforming growth factor β (TGF-β) signaling. Loss of its activity causes cerebral autosomal recessive arteriopathy with subcortical infarcts and leukoencephalopathy (CARASIL), an inherited form of cerebral small vessel disease leading to early-onset stroke and premature dementia. Dysregulated TGF-β signaling is considered to promote CARASIL pathogenesis, but the underlying molecular mechanisms are incompletely understood. Here we present evidence from mouse brain tissue and embryonic fibroblasts as well as patient skin fibroblasts for a facilitating role of HtrA1 in TGF-β pathway activation. We identify latent TGF-β binding protein 1 (LTBP-1), an extracellular matrix protein and key regulator of TGF-β bioavailability, as a novel HtrA1 target. Cleavage occurs at physiological protease concentrations, is prevented under HtrA1-deficient conditions as well as by CARASIL mutations and disrupts both LTBP-1 binding to fibronectin and its incorporation into the extracellular matrix. Hence, our data suggest an attenuation of TGF-β signaling caused by a lack of HtrA1-mediated LTBP-1 processing as mechanism underlying CARASIL pathogenesis.
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Affiliation(s)
- Nathalie Beaufort
- Institute for Stroke and Dementia Research, Klinikum der Universität München, Ludwig Maximilians University, 81377 Munich, Germany
| | - Eva Scharrer
- Institute for Stroke and Dementia Research, Klinikum der Universität München, Ludwig Maximilians University, 81377 Munich, Germany
| | - Elisabeth Kremmer
- Institute of Molecular Immunology, Helmholtz-Zentrum München, 81377 Munich, Germany
| | - Vanda Lux
- Centre for Medical Biotechnology, Faculty of Biology, University of Duisburg-Essen, 45141 Essen, Germany
| | - Michael Ehrmann
- Centre for Medical Biotechnology, Faculty of Biology, University of Duisburg-Essen, 45141 Essen, Germany
| | - Robert Huber
- Centre for Medical Biotechnology, Faculty of Biology, University of Duisburg-Essen, 45141 Essen, Germany; Emeritus Group Structure Research, Max Planck Institute of Biochemistry, 82152 Martinsried, Germany; Center for Integrated Protein Science at the Department of Chemistry, Lehrstuhl für Biochemie, Technische Unversität München, 85748 Garching, Germany; School of Biosciences, Cardiff University, Cardiff CF10 3US, Wales, United Kingdom;
| | - Henry Houlden
- Department of Molecular Neuroscience and Neurogenetics Laboratory, University College London (UCL) Institute of Neurology and The National Hospital for Neurology and Neurosurgery, London WC1N 3BG, United Kingdom
| | - David Werring
- Stroke Research Group, Department of Brain Repair and Rehabilitation, UCL Institute of Neurology and The National Hospital for Neurology and Neurosurgery, London WC1N 3BG, United Kingdom; and
| | - Christof Haffner
- Institute for Stroke and Dementia Research, Klinikum der Universität München, Ludwig Maximilians University, 81377 Munich, Germany;
| | - Martin Dichgans
- Institute for Stroke and Dementia Research, Klinikum der Universität München, Ludwig Maximilians University, 81377 Munich, Germany; Munich Cluster for Systems Neurology (SyNergy), 80336 Munich, Germany
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De Silva TM, Ketsawatsomkron P, Pelham C, Sigmund CD, Faraci FM. Genetic interference with peroxisome proliferator-activated receptor γ in smooth muscle enhances myogenic tone in the cerebrovasculature via A Rho kinase-dependent mechanism. Hypertension 2014; 65:345-51. [PMID: 25385762 DOI: 10.1161/hypertensionaha.114.04541] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Myogenic responses by resistance vessels are a key component of autoregulation in brain, thus playing a crucial role in regulating cerebral blood flow and protecting the blood-brain barrier against potentially detrimental elevations in blood pressure. Although cerebrovascular disease is often accompanied by alterations in myogenic responses, mechanisms that control these changes are poorly understood. Peroxisome proliferator-activated receptor γ has emerged as a regulator of vascular tone. We hypothesized that interference with peroxisome proliferator-activated receptor γ in smooth muscle would augment myogenic responses in cerebral arteries. We studied transgenic mice expressing a dominant-negative mutation in peroxisome proliferator-activated receptor γ selectively in smooth muscle (S-P467L) and nontransgenic littermates. Myogenic tone in middle cerebral arteries from S-P467L was elevated 3-fold when compared with nontransgenic littermates. Rho kinase is thought to play a major role in cerebrovascular disease. The Rho kinase inhibitor, Y-27632, abolished augmented myogenic tone in middle cerebral arteries from S-P467L mice. CN-03, which modifies RhoA making it constitutively active, elevated myogenic tone to ≈60% in both strains, via a Y-27632-dependent mechanism. Large conductance Ca(2+)-activated K(+) channels (BKCa) modulate myogenic tone. Inhibitors of BKCa caused greater constriction in middle cerebral arteries from nontransgenic littermates when compared with S-P467L. Expression of RhoA or Rho kinase-I/II protein was similar in cerebral arteries from S-P467L mice. Overall, the data suggest that peroxisome proliferator-activated receptor γ in smooth muscle normally inhibits Rho kinase and promotes BKCa function, thus influencing myogenic tone in resistance arteries in brain. These findings have implications for mechanisms that underlie large- and small-vessel disease in brain, as well as regulation of cerebral blood flow.
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Affiliation(s)
- T Michael De Silva
- From the Departments of Internal Medicine (T.M.D.S., C.D.S, F.M.F.) and Pharmacology (P.K., C.P., C.D.S., F.M.F.), Francois M. Abboud Cardiovascular Center, The University of Iowa Carver College of Medicine; and Veterans Affairs Healthcare System, Iowa City, IA (F.M.F.)
| | - Pimonrat Ketsawatsomkron
- From the Departments of Internal Medicine (T.M.D.S., C.D.S, F.M.F.) and Pharmacology (P.K., C.P., C.D.S., F.M.F.), Francois M. Abboud Cardiovascular Center, The University of Iowa Carver College of Medicine; and Veterans Affairs Healthcare System, Iowa City, IA (F.M.F.)
| | - Christopher Pelham
- From the Departments of Internal Medicine (T.M.D.S., C.D.S, F.M.F.) and Pharmacology (P.K., C.P., C.D.S., F.M.F.), Francois M. Abboud Cardiovascular Center, The University of Iowa Carver College of Medicine; and Veterans Affairs Healthcare System, Iowa City, IA (F.M.F.)
| | - Curt D Sigmund
- From the Departments of Internal Medicine (T.M.D.S., C.D.S, F.M.F.) and Pharmacology (P.K., C.P., C.D.S., F.M.F.), Francois M. Abboud Cardiovascular Center, The University of Iowa Carver College of Medicine; and Veterans Affairs Healthcare System, Iowa City, IA (F.M.F.)
| | - Frank M Faraci
- From the Departments of Internal Medicine (T.M.D.S., C.D.S, F.M.F.) and Pharmacology (P.K., C.P., C.D.S., F.M.F.), Francois M. Abboud Cardiovascular Center, The University of Iowa Carver College of Medicine; and Veterans Affairs Healthcare System, Iowa City, IA (F.M.F.).
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Kast J, Hanecker P, Beaufort N, Giese A, Joutel A, Dichgans M, Opherk C, Haffner C. Sequestration of latent TGF-β binding protein 1 into CADASIL-related Notch3-ECD deposits. Acta Neuropathol Commun 2014; 2:96. [PMID: 25190493 PMCID: PMC4243959 DOI: 10.1186/s40478-014-0096-8] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2014] [Accepted: 08/04/2014] [Indexed: 12/20/2022] Open
Abstract
Introduction Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) represents the most common hereditary form of cerebral small vessel disease characterized by early-onset stroke and premature dementia. It is caused by mutations in the transmembrane receptor Notch3, which promote the aggregation and accumulation of the Notch3 extracellular domain (Notch3-ECD) within blood vessel walls. This process is believed to mediate the abnormal recruitment and dysregulation of additional factors including extracellular matrix (ECM) proteins resulting in brain vessel dysfunction. Based on recent evidence indicating a role for the transforming growth factor-β (TGF-β) pathway in sporadic and familial small vessel disease we studied fibronectin, fibrillin-1 and latent TGF-β binding protein 1 (LTBP-1), three ECM constituents involved in the regulation of TGF-β bioavailability, in post-mortem brain tissue from CADASIL patients and control subjects. Results Fibronectin and fibrillin-1 were found to be enriched in CADASIL vessels without co-localizing with Notch3-ECD deposits, likely as a result of fibrotic processes secondary to aggregate formation. In contrast, LTBP-1 showed both an accumulation and a striking co-localization with Notch3-ECD deposits suggesting specific recruitment into aggregates. We also detected increased levels of the TGF-β prodomain (also known as latency-associated peptide, LAP) indicating dysregulation of the TGF-β pathway in CADASIL development. In vitro analyses revealed a direct interaction between LTBP-1 and Notch3-ECD and demonstrated a specific co-aggregation of LTBP-1 with mutant Notch3. Conclusion We propose LTBP-1 as a novel component of Notch3-ECD deposits and suggest its involvement in pathological processes triggered by Notch3-ECD aggregation. Electronic supplementary material The online version of this article (doi:10.1186/s40478-014-0096-8) contains supplementary material, which is available to authorized users.
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Cognat E, Cleophax S, Domenga-Denier V, Joutel A. Early white matter changes in CADASIL: evidence of segmental intramyelinic oedema in a pre-clinical mouse model. Acta Neuropathol Commun 2014; 2:49. [PMID: 24886907 PMCID: PMC4035092 DOI: 10.1186/2051-5960-2-49] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2014] [Accepted: 04/22/2014] [Indexed: 01/28/2023] Open
Abstract
Introduction Small vessel disease (SVD) of the brain is a leading cause of age- and hypertension-related cognitive decline and disability. Cerebral white matter changes are a consistent manifestation of SVD on neuroimaging, progressing silently for many years before becoming clinically evident. The pathogenesis of these changes remains poorly understood, despite their importance. In particular, their pathological correlate at early stages remains largely undefined. Cerebral Autosomal Dominant Arteriopathy with Subcortical Infarcts and Leukoencephalopathy (CADASIL), caused by dominant mutations of the NOTCH3 receptor, is regarded as a paradigm for the most common form of sporadic SVD. In this study, we used immunohistochemistry, confocal microscopy and electron microscopy, together with qualitative and quantitative analyses to assess oligodendroglial, axon and myelin damage in TgPAC-Notch3R169C mice, a model of preclinical CADASIL. Results The principal cerebral white matter changes in TgPAC-Notch3R169C mice are microvacuoles (≤1 μm diameter) in the myelin sheaths associated with focal myelin degradation and occurring in the absence of oligodendrocyte loss. Half the damaged myelin sheaths still contain an apparently intact axon. Clearance of myelin debris appears inefficient, as demonstrated by the significant but mild microglial reaction, with occasional myelin debris either contacted or internalized by microglial cells. Conclusion Our findings suggest that segmental intramyelinic oedema is an early, conspicuous white matter change in CADASIL. Brain white matter intramyelinic oedema is consistently found in patients and mouse models with compromised ion and water homeostasis. These data provide a starting point for novel mechanistic studies to investigate the pathogenesis of SVD-related white matter changes. Electronic supplementary material The online version of this article (doi:10.1186/2051-5960-2-49) contains supplementary material, which is available to authorized users.
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