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Wang Z, Li Y, Wang Z, Liao Y, Ye Q, Tang S, Wei T, Xiao P, Huang J, Lu W. Edaravone Maintains AQP4 Polarity Via OS/MMP9/β-DG Pathway in an Experimental Intracerebral Hemorrhage Mouse Model. Mol Neurobiol 2024:10.1007/s12035-024-04028-4. [PMID: 38421470 DOI: 10.1007/s12035-024-04028-4] [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: 12/05/2023] [Accepted: 02/09/2024] [Indexed: 03/02/2024]
Abstract
Oxidative stress (OS) is the main cause of secondary damage following intracerebral hemorrhage (ICH). The polarity expression of aquaporin-4 (AQP4) has been shown to be important in maintaining the homeostasis of water transport and preventing post-injury brain edema in various neurological disorders. This study primarily aimed to investigate the effect of the oxygen free radical scavenger, edaravone, on AQP4 polarity expression in an ICH mouse model and determine whether it involves in AQP4 polarity expression via the OS/MMP9/β-dystroglycan (β-DG) pathway. The ICH mouse model was established by autologous blood injection into the basal nucleus. Edaravone or the specific inhibitor of matrix metalloproteinase 9 (MMP9), MMP9-IN-1, called MMP9-inh was administered 10 min after ICH via intraperitoneal injection. ELISA detection, neurobehavioral tests, dihydroethidium staining (DHE staining), intracisternal tracer infusion, hematoxylin and eosin (HE) staining, immunofluorescence staining, western blotting, Evans blue (EB) permeability assay, and brain water content test were performed. The results showed that OS was exacerbated, AQP4 polarity was lost, drainage function of brain fluids was damaged, brain injury was aggravated, expression of AQP4, MMP9, and GFAP increased, while the expression of β-DG decreased after ICH. Edaravone reduced OS, restored brain drainage function, reduced brain injury, and downregulated the expression of AQP4, MMP9. Both edaravone and MMP9-inh alleviated brain edema, maintained blood-brain barrier (BBB) integrity, mitigated the loss of AQP4 polarity, downregulated GFAP expression, and upregulated β-DG expression. The current study suggests that edaravone can maintain AQP4 polarity expression by inhibiting the OS /MMP9/β-DG pathway after ICH.
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Affiliation(s)
- Zhenhua Wang
- Department of Anatomy, Basic Medical College, Chongqing Medical University, Chongqing, China
- Institute of Neuroscience, Basic Medical College, Chongqing Medical University, Chongqing, China
| | - Yuan Li
- Department of Anatomy, Basic Medical College, Chongqing Medical University, Chongqing, China
- Institute of Neuroscience, Basic Medical College, Chongqing Medical University, Chongqing, China
| | - Zhixu Wang
- Department of Anatomy, Basic Medical College, Chongqing Medical University, Chongqing, China
- Institute of Neuroscience, Basic Medical College, Chongqing Medical University, Chongqing, China
| | - Yuhui Liao
- Department of Anatomy, Basic Medical College, Chongqing Medical University, Chongqing, China
- Institute of Neuroscience, Basic Medical College, Chongqing Medical University, Chongqing, China
- Sichuan University of Arts and Science, Sichuan, China
| | - Qingqing Ye
- Department of Anatomy, Basic Medical College, Chongqing Medical University, Chongqing, China
- Institute of Neuroscience, Basic Medical College, Chongqing Medical University, Chongqing, China
| | - Shilong Tang
- Department of Anatomy, Basic Medical College, Chongqing Medical University, Chongqing, China
- Institute of Neuroscience, Basic Medical College, Chongqing Medical University, Chongqing, China
- Department of Radiology, Children's Hospital of Chongqing Medical University, Chongqing, China
| | - Ting Wei
- Department of Anatomy, Basic Medical College, Chongqing Medical University, Chongqing, China
- Institute of Neuroscience, Basic Medical College, Chongqing Medical University, Chongqing, China
| | - Pengyu Xiao
- Department of Anatomy, Basic Medical College, Chongqing Medical University, Chongqing, China
- Institute of Neuroscience, Basic Medical College, Chongqing Medical University, Chongqing, China
| | - Juan Huang
- Department of Anatomy, Basic Medical College, Chongqing Medical University, Chongqing, China.
- Institute of Neuroscience, Basic Medical College, Chongqing Medical University, Chongqing, China.
| | - Weitian Lu
- Department of Anatomy, Basic Medical College, Chongqing Medical University, Chongqing, China.
- Institute of Neuroscience, Basic Medical College, Chongqing Medical University, Chongqing, China.
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Si X, Dai S, Fang Y, Tang J, Wang Z, Li Y, Song Z, Chen Y, Liu Y, Zhao G, Zhang B, Pu J. Matrix metalloproteinase-9 inhibition prevents aquaporin-4 depolarization-mediated glymphatic dysfunction in Parkinson's disease. J Adv Res 2024; 56:125-136. [PMID: 36940850 PMCID: PMC10834796 DOI: 10.1016/j.jare.2023.03.004] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2022] [Revised: 01/31/2023] [Accepted: 03/14/2023] [Indexed: 03/23/2023] Open
Abstract
INTRODUCTION The glymphatic system offers a perivascular pathway for the clearance of pathological proteins and metabolites to optimize neurological functions. Glymphatic dysfunction plays a pathogenic role in Parkinson's disease (PD); however, the molecular mechanism of glymphatic dysfunction in PD remains elusive. OBJECTIVE To explore whether matrix metalloproteinase-9 (MMP-9)-mediated β-dystroglycan (β-DG) cleavage is involved in the regulation of aquaporin-4 (AQP4) polarity-mediated glymphatic system in PD. METHODS 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced PD and A53T mice were used in this study. The glymphatic function was evaluated using ex vivo imaging. TGN-020, an AQP4 antagonist, was administered to investigate the role of AQP4 in glymphatic dysfunction in PD. GM6001, an MMP-9 antagonist, was administered to investigate the role of the MMP-9/β-DG pathway in regulating AQP4. The expression and distribution of AQP4, MMP-9, and β-DG were assessed using western blotting, immunofluorescence, and co-immunoprecipitation. The ultrastructure of basement membrane (BM)-astrocyte endfeet was detected using transmission electron microscopy. Rotarod and open-field tests were performed to evaluate motor behavior. RESULTS Perivascular influx and efflux of cerebral spinal fluid tracers were reduced in MPTP-induced PD mice with impaired AQP4 polarization. AQP4 inhibition aggravated reactive astrogliosis, glymphatic drainage restriction, and dopaminergic neuronal loss in MPTP-induced PD mice. MMP-9 and cleaved β-DG were upregulated in both MPTP-induced PD and A53T mice, with reduced polarized localization of β-DG and AQP4 to astrocyte endfeet. MMP-9 inhibition restored BM-astrocyte endfeet-AQP4 integrity and attenuated MPTP-induced metabolic perturbations and dopaminergic neuronal loss. CONCLUSION AQP4 depolarization contributes to glymphatic dysfunction and aggravates PD pathologies, and MMP-9-mediated β-DG cleavage regulates glymphatic function through AQP4 polarization in PD, which may provide novel insights into the pathogenesis of PD.
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Affiliation(s)
- Xiaoli Si
- Department of Neurology, The Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang 310009, China; Department of Neurology, The Fourth Affiliated Hospital, International Institutes of Medicine, Zhejiang University, School of Medicine, Yiwu, Zhejiang 322000, China
| | - Shaobing Dai
- Department of Anesthesiology, Women's Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang 310009, China
| | - Yi Fang
- Department of Neurology, The Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang 310009, China
| | - Jiahui Tang
- Department of Neurology, The Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang 310009, China
| | - Zhiyun Wang
- Department of Neurology, The Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang 310009, China
| | - Yaolin Li
- Department of Neurology, The Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang 310009, China
| | - Zhe Song
- Department of Neurology, The Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang 310009, China
| | - Ying Chen
- Department of Neurology, The Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang 310009, China
| | - Yi Liu
- Department of Neurology, The Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang 310009, China
| | - Guohua Zhao
- Department of Neurology, The Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang 310009, China; Department of Neurology, The Fourth Affiliated Hospital, International Institutes of Medicine, Zhejiang University, School of Medicine, Yiwu, Zhejiang 322000, China.
| | - Baorong Zhang
- Department of Neurology, The Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang 310009, China.
| | - Jiali Pu
- Department of Neurology, The Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang 310009, China.
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Bonosi L, Benigno UE, Musso S, Giardina K, Gerardi RM, Brunasso L, Costanzo R, Paolini F, Buscemi F, Avallone C, Gulino V, Iacopino DG, Maugeri R. The Role of Aquaporins in Epileptogenesis-A Systematic Review. Int J Mol Sci 2023; 24:11923. [PMID: 37569297 PMCID: PMC10418736 DOI: 10.3390/ijms241511923] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2023] [Revised: 07/20/2023] [Accepted: 07/23/2023] [Indexed: 08/13/2023] Open
Abstract
Aquaporins (AQPs) are a family of membrane proteins involved in the transport of water and ions across cell membranes. AQPs have been shown to be implicated in various physiological and pathological processes in the brain, including water homeostasis, cell migration, and inflammation, among others. Epileptogenesis is a complex and multifactorial process that involves alterations in the structure and function of neuronal networks. Recent evidence suggests that AQPs may also play a role in the pathogenesis of epilepsy. In animal models of epilepsy, AQPs have been shown to be upregulated in regions of the brain that are involved in seizure generation, suggesting that they may contribute to the hyperexcitability of neuronal networks. Moreover, genetic studies have identified mutations in AQP genes associated with an increased risk of developing epilepsy. Our review aims to investigate the role of AQPs in epilepsy and seizure onset from a pathophysiological point of view, pointing out the potential molecular mechanism and their clinical implications.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | | | | | - Rosario Maugeri
- Neurosurgical Clinic, AOUP “Paolo Giaccone”, Post Graduate Residency Program in Neurologic Surgery, Department of Biomedicine Neurosciences and Advanced Diagnostics, School of Medicine, University of Palermo, 90127 Palermo, Italy; (L.B.); (U.E.B.); (S.M.); (K.G.); (R.M.G.); (L.B.); (R.C.); (F.P.); (F.B.); (C.A.); (V.G.); (D.G.I.)
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Kawauchi S, Mizoguchi T, Horibe S, Tanaka T, Sasaki N, Ikeda K, Emoto N, Hirata KI, Rikitake Y. Gliovascular interface abnormality in mice with endothelial cell senescence. Glia 2023; 71:467-479. [PMID: 36286494 DOI: 10.1002/glia.24287] [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: 05/01/2022] [Revised: 10/06/2022] [Accepted: 10/10/2022] [Indexed: 12/24/2022]
Abstract
In the brain, neurons, glial cells, vascular endothelial cells (ECs), and mural cells form a functional structure referred to as the neurovascular unit (NVU). The functions of the NVU become impaired with aging. To gain insight into the mechanism underlying the aging-related changes in the NVU, we characterized in the present study the gliovascular interface in transgenic mice expressing a dominant-negative form of the telomeric repeat-binding factor 2 (TERF2) specifically in ECs using the Tie2 promoter. In these transgenic mice, senescence occurred in the cerebral ECs and was accompanied by upregulation of the mRNAs of proinflammatory cell adhesion molecules and cytokines. It is noteworthy that in the deep layers of the cerebral cortex, astrocytes exhibited an increase in the signals for S100β as well as a decrease in the polarization of the water channel aquaporin-4 (AQP4) to the perivascular endfeet of the astrocytes. Mechanistically, the perivascular localization of dystroglycan and its ligand, laminin α2, was decreased, and their localization correlated well with the perivascular localization of AQP4, which supports the notion that their interaction regulates the perivascular localization of AQP4. The diminished perivascular localization of laminin α2 may be attributed to its proteolytic degradation by the matrix metalloproteinase-2 released by senescent ECs. Pericyte coverage was increased and negatively correlated with the decrease in the perivascular localization of AQP4. We propose that aging-related changes in ECs induce a mild morphological alteration of astrocytes and affect the localization of AQP4 at the gliovascular interface.
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Affiliation(s)
- Shoji Kawauchi
- Comprehensive Education and Research Center, Kobe Pharmaceutical University, Kobe, Japan
| | - Taiji Mizoguchi
- Laboratory of Medical Pharmaceutics, Kobe Pharmaceutical University, Kobe, Japan
| | - Sayo Horibe
- Laboratory of Medical Pharmaceutics, Kobe Pharmaceutical University, Kobe, Japan
| | - Toru Tanaka
- Laboratory of Medical Pharmaceutics, Kobe Pharmaceutical University, Kobe, Japan
| | - Naoto Sasaki
- Laboratory of Medical Pharmaceutics, Kobe Pharmaceutical University, Kobe, Japan
| | - Koji Ikeda
- Laboratory of Clinical Pharmaceutical Science, Kobe Pharmaceutical University, Kobe, Japan
| | - Noriaki Emoto
- Laboratory of Clinical Pharmaceutical Science, Kobe Pharmaceutical University, Kobe, Japan
| | - Ken-Ichi Hirata
- Division of Cardiovascular Medicine, Department of Internal Medicine, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Yoshiyuki Rikitake
- Laboratory of Medical Pharmaceutics, Kobe Pharmaceutical University, Kobe, Japan
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Lin S, Zhou FQ, Cheng JB, Sun XD, He GQ. Editorial: The role of astrocyte in vascular aging. Front Aging Neurosci 2022; 14:961288. [PMID: 35992606 PMCID: PMC9382830 DOI: 10.3389/fnagi.2022.961288] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2022] [Accepted: 06/16/2022] [Indexed: 11/13/2022] Open
Affiliation(s)
- Sen Lin
- Department of Neurology, The Second Affiliated Hospital, Army Medical University, Chongqing, China
- *Correspondence: Sen Lin
| | - Feng-Quan Zhou
- Department of Orthopedic Surgery, Johns Hopkins University School of Medicine, Baltimore, MD, United States
- Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD, United States
| | - Jin-Bo Cheng
- College of Life and Environmental Sciences, Minzu University of China, Beijing, China
| | - Xiang-Dong Sun
- Key Laboratory of Neuroscience, School of Basic Medical Sciences, Guangzhou Medical University, Guangzhou, China
| | - Gui-Qiong He
- Chongqing Key Laboratory of Neurobiology, Department of Anatomy, Institute of Neuroscience, Chongqing Medical University, Chongqing, China
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Kimball EC, Quillen S, Pease ME, Keuthan C, Nagalingam A, Zack DJ, Johnson TV, Quigley HA. Aquaporin 4 is not present in normal porcine and human lamina cribrosa. PLoS One 2022; 17:e0268541. [PMID: 35709078 PMCID: PMC9202842 DOI: 10.1371/journal.pone.0268541] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2021] [Accepted: 05/03/2022] [Indexed: 02/02/2023] Open
Abstract
Aquaporin 4 is absent from astrocytes in the rodent optic nerve head, despite high expression in the retina and myelinated optic nerve. The purpose of this study was to quantify regional aquaporin channel expression in astrocytes of the porcine and human mouse optic nerve (ON). Ocular tissue sections were immunolabeled for aquaporins 1(AQP1), 4(AQP4), and 9(AQP9), myelin basic protein (MBP), glial fibrillary acidic protein (GFAP) and alpha-dystroglycan (αDG) for their presence in retina, lamina, myelin transition zone (MTZ, region just posterior to lamina) and myelinated ON (MON). Semi- quantification of AQP4 labeling & real-time quantitative PCR (qPCR) data were analyzed in retina and ON tissue. Porcine and control human eyes had abundant AQP4 in Müller cells, retinal astrocytes, and myelinated ON (MON), but minimal expression in the lamina cribrosa. AQP1 and AQP9 were present in retina, but not in the lamina. Immunolabeling of GFAP and αDG was similar in lamina, myelin transition zone (MTZ) and MON regions. Semi-quantitative AQP4 labeling was at background level in lamina, increasing in the MTZ, and highest in the MON (lamina vs MTZ, MON; p≤0.05, p≤0.01, respectively). Expression of AQP4 mRNA was minimal in lamina and substantial in MTZ and MON, while GFAP mRNA expression was uniform among the lamina, MTZ, and MON regions. Western blot assay showed AQP4 protein expression in the MON samples, but none was detected in the lamina tissue. The minimal presence of AQP4 in the lamina is a specific regional phenotype of astrocytes in the mammalian optic nerve head.
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Affiliation(s)
- Elizabeth C. Kimball
- Glaucoma Center of Excellence, Wilmer Eye Institute, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Sarah Quillen
- Glaucoma Center of Excellence, Wilmer Eye Institute, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Mary E. Pease
- Glaucoma Center of Excellence, Wilmer Eye Institute, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Casey Keuthan
- Glaucoma Center of Excellence, Wilmer Eye Institute, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Aru Nagalingam
- Glaucoma Center of Excellence, Wilmer Eye Institute, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Donald J. Zack
- Glaucoma Center of Excellence, Wilmer Eye Institute, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Thomas V. Johnson
- Glaucoma Center of Excellence, Wilmer Eye Institute, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Harry A. Quigley
- Glaucoma Center of Excellence, Wilmer Eye Institute, Johns Hopkins University, Baltimore, Maryland, United States of America
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The cell adhesion protein dystroglycan affects the structural remodeling of dendritic spines. Sci Rep 2022; 12:2506. [PMID: 35169214 PMCID: PMC8847666 DOI: 10.1038/s41598-022-06462-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Accepted: 01/28/2022] [Indexed: 11/30/2022] Open
Abstract
Dystroglycan (DG) is a cell membrane protein that binds to the extracellular matrix in various mammalian tissues. The function of DG has been well defined in embryonic development as well as in the proper migration of differentiated neuroblasts in the central nervous system (CNS). Although DG is known to be a target for matrix metalloproteinase-9 (MMP-9), cleaved in response to enhanced synaptic activity, the role of DG in the structural remodeling of dendritic spines is still unknown. Here, we report for the first time that the deletion of DG in rat hippocampal cell cultures causes pronounced changes in the density and morphology of dendritic spines. Furthermore, we noted a decrease in laminin, one of the major extracellular partners of DG. We have also observed that the lack of DG evokes alterations in the morphological complexity of astrocytes accompanied by a decrease in the level of aquaporin 4 (AQP4), a protein located within astrocyte endfeet surrounding neuronal dendrites and synapses. Regardless of all of these changes, we did not observe any effect of DG silencing on either excitatory or inhibitory synaptic transmission. Likewise, the knockdown of DG had no effect on Psd-95 protein expression. Our results indicate that DG is involved in dendritic spine remodeling that is not functionally reflected. This may suggest the existence of unknown mechanisms that maintain proper synaptic signaling despite impaired structure of dendritic spines. Presumably, astrocytes are involved in these processes.
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Spampinato SF, Takeshita Y, Obermeier B. An In Vitro Model of the Blood-Brain Barrier to Study Alzheimer's Disease: The Role of β-Amyloid and Its Influence on PBMC Infiltration. Methods Mol Biol 2022; 2492:333-352. [PMID: 35733055 DOI: 10.1007/978-1-0716-2289-6_20] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
The blood-brain barrier (BBB) is a highly specialized structure, constituted by endothelial cells that together with astrocytes and pericytes provide a functional interface between the central nervous system and the periphery. Several pathological conditions may affect its functions, and lately BBB involvement in the pathogenesis of Alzheimer's disease has been demonstrated. Both endothelial cells and astrocytes can be differentially affected during the course of the disease. In vitro BBB models present a powerful tool in evaluating the effects that β-amyloid (Aβ), or other pathogenic stimuli, play on the BBB at cellular level. In vitro BBB models derived from human cell sources are rare and not easily implemented. We generated two conditionally immortalized human cell lines, brain microvascular endothelial cells (TY10), and astrocytes (hAST), that, when co-cultured under appropriate conditions, exhibit BBB-like characteristics. This model allowed us to evaluate the transmigration of peripheral blood mononuclear cells (PBMCs) through the in vitro barrier exposed to Aβ and the role played by astrocytes in the modulation of this phenomenon. We describe here the methodology used in our lab to set up our in vitro model of the BBB and to carry out a PBMC transmigration assay.
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Affiliation(s)
- Simona Federica Spampinato
- Department of Biomedical and Biotechnological Sciences, Section of Pharmacology, University of Catania, Catania, Italy.
- Departement of Scienza e Tecnologia del Farmaco, Universita' di Turin, Turin, Italy.
| | - Yukio Takeshita
- Department of Neurology and Clinical Neuroscience, Yamaguchi University Graduate School of Medicine, Ube, Yamaguchi, Japan
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Price BR, Johnson LA, Norris CM. Reactive astrocytes: The nexus of pathological and clinical hallmarks of Alzheimer's disease. Ageing Res Rev 2021; 68:101335. [PMID: 33812051 PMCID: PMC8168445 DOI: 10.1016/j.arr.2021.101335] [Citation(s) in RCA: 62] [Impact Index Per Article: 20.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2020] [Revised: 01/21/2021] [Accepted: 03/20/2021] [Indexed: 02/06/2023]
Abstract
Astrocyte reactivity is a hallmark of neuroinflammation that arises with Alzheimer’s disease (AD) and nearly every other neurodegenerative condition. While astrocytes certainly contribute to classic inflammatory processes (e.g. cytokine release, waste clearance, and tissue repair), newly emerging technologies for measuring and targeting cell specific activities in the brain have uncovered essential roles for astrocytes in synapse function, brain metabolism, neurovascular coupling, and sleep/wake patterns. In this review, we use a holistic approach to incorporate, and expand upon, classic neuroinflammatory concepts to consider how astrocyte dysfunction/reactivity modulates multiple pathological and clinical hallmarks of AD. Our ever-evolving understanding of astrocyte signaling in neurodegeneration is not only revealing new drug targets and treatments for dementia but is suggesting we reimagine AD pathophysiological mechanisms.
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Affiliation(s)
- Brittani R Price
- Department of Neuroscience, Tufts University School of Medicine, 136 Harrison Ave., Boston, MA, 02111, USA
| | - Lance A Johnson
- Sanders-Brown Center on Aging, University of Kentucky, 800 S. Limestone St., Lexington, KY, 40356, USA; Department of Physiology, University of Kentucky, College of Medicine, UK Medical Center MN 150, Lexington, KY, 40536, USA
| | - Christopher M Norris
- Sanders-Brown Center on Aging, University of Kentucky, 800 S. Limestone St., Lexington, KY, 40356, USA; Department of Pharmacology and Nutritional Sciences, University of Kentucky, College of Medicine, UK Medical Center MN 150, Lexington, KY, 40536, USA.
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Ramadhanti J, Yamada T, Yasui M, Nuriya M. Differentially regulated pools of aquaporin-4 (AQP4) proteins in the cerebral cortex revealed by biochemical fractionation analyses. J Pharmacol Sci 2021; 146:58-64. [PMID: 33858656 DOI: 10.1016/j.jphs.2021.03.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2021] [Revised: 03/05/2021] [Accepted: 03/09/2021] [Indexed: 11/29/2022] Open
Abstract
Aquaporin-4 (AQP4) is a predominant water channel in the central nervous system. It regulates water movement in the brain and has been suggested to play critical roles in various pathological conditions. However, the molecular mechanisms underlying its regulation are not yet well understood. In this study, we biochemically characterized AQP4 in the brain using acute cortical brain slices prepared from mice. Using biochemical fractionation, we found that AQP4 is enriched in the detergent-resistant membrane (DRM) fraction that is not soluble in 1% Triton X-100. In contrast, β-dystroglycan and syntrophin, which are part of the dystrophin complex in the brain, primarily reside in the non-DRM fraction. DRM enrichment of AQP4 is insensitive to cholesterol depletion, suggesting that it is not tightly associated with lipid rafts. Furthermore, AQP4 in the DRM fraction is more enriched in the M23 isoform than in the non-DRM fraction. Finally, by employing oxygen-glucose deprivation (OGD), an in vitro model of ischemia, we examined the molecular changes of AQP4. Under OGD conditions, a reduction in AQP4 in the DRM fraction was observed before the total AQP4 protein level dropped. Our data therefore highlight the characteristics of two pools of AQP4 that are distinctly regulated under ischemic conditions.
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Affiliation(s)
- Julia Ramadhanti
- Department of Pharmacology School of Medicine, Keio University, 35 Shinanomachi, Shinjuku-ku, Tokyo, 160-8582, Japan; Department of Biomedical Science, Medical Faculty, Universitas Padjadjaran, Jalan Professor Eijkman no.38, Bandung, 40161, Indonesia
| | - Tomoko Yamada
- Department of Pharmacology School of Medicine, Keio University, 35 Shinanomachi, Shinjuku-ku, Tokyo, 160-8582, Japan
| | - Masato Yasui
- Department of Pharmacology School of Medicine, Keio University, 35 Shinanomachi, Shinjuku-ku, Tokyo, 160-8582, Japan; Keio Advanced Research Center for Water Biology and Medicine, Keio University, 2-15-45 Mita, Minato-ku, Tokyo, 108-8345, Japan
| | - Mutsuo Nuriya
- Department of Pharmacology School of Medicine, Keio University, 35 Shinanomachi, Shinjuku-ku, Tokyo, 160-8582, Japan; Graduate School of Environment and Information Sciences, Yokohama National University, Kanagawa, 240-8501, Japan; Precursory Research for Embryonic Science and Technology (PRESTO), Japan Science and Technology Agency (JST), Kawaguchi, Saitama, 332-0012, Japan; Keio Advanced Research Center for Water Biology and Medicine, Keio University, 2-15-45 Mita, Minato-ku, Tokyo, 108-8345, Japan.
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11
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Kimball E, Schaub J, Quillen S, Keuthan C, Pease ME, Korneva A, Quigley H. The role of aquaporin-4 in optic nerve head astrocytes in experimental glaucoma. PLoS One 2021; 16:e0244123. [PMID: 33529207 PMCID: PMC7853498 DOI: 10.1371/journal.pone.0244123] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Accepted: 01/11/2021] [Indexed: 02/04/2023] Open
Abstract
PURPOSE To study aquaporin channel expression in astrocytes of the mouse optic nerve (ON) and the response to IOP elevation in mice lacking aquaporin 4 (AQP4 null). METHODS C57BL/6 (B6) and AQP4 null mice were exposed to bead-induced IOP elevation for 3 days (3D-IOP), 1 and 6 weeks. Mouse ocular tissue sections were immunolabeled against aquaporins 1(AQP1), 4(AQP4), and 9(AQP9). Ocular tissue was imaged to identify normal AQP distribution, ON changes, and axon loss after IOP elevation. Ultrastructure examination, cell proliferation, gene expression, and transport block were also analyzed. RESULTS B6 mice had abundant AQP4 expression in Müller cells, astrocytes of retina and myelinated ON (MON), but minimal AQP4in prelaminar and unmyelinated ON (UON). MON of AQP4 nulls had smaller ON area, smaller axon diameter, higher axon density, and larger proportionate axon area than B6 (all p≤0.05). Bead-injection led to comparable 3D-IOP elevation (p = 0.42) and axonal transport blockade in both strains. In B6, AQP4 distribution was unchanged after 3D-IOP. At baseline, AQP1 and AQP9 were present in retina, but not in UON and this was unaffected after IOP elevation in both strains. In 3D-IOP mice, ON astrocytes and microglia proliferated, more in B6 than AQP4 null. After 6 week IOP elevation, axon loss occurred equally in the two mouse types (24.6%, AQP4 null vs. 23.3%, B6). CONCLUSION Lack of AQP4 was neither protective nor detrimental to the effects of IOP elevation. The minimal presence of AQP4 in UON may be a vital aspect of the regionally specific phenotype of astrocytes in the mouse optic nerve head.
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Affiliation(s)
- Elizabeth Kimball
- Glaucoma Center of Excellence, Wilmer Eye Institute, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Julie Schaub
- Glaucoma Center of Excellence, Wilmer Eye Institute, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Sarah Quillen
- Glaucoma Center of Excellence, Wilmer Eye Institute, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Casey Keuthan
- Glaucoma Center of Excellence, Wilmer Eye Institute, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Mary Ellen Pease
- Glaucoma Center of Excellence, Wilmer Eye Institute, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Arina Korneva
- Glaucoma Center of Excellence, Wilmer Eye Institute, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Harry Quigley
- Glaucoma Center of Excellence, Wilmer Eye Institute, Johns Hopkins University, Baltimore, Maryland, United States of America
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Moretti R, Caruso P. Small Vessel Disease-Related Dementia: An Invalid Neurovascular Coupling? Int J Mol Sci 2020; 21:E1095. [PMID: 32046035 PMCID: PMC7036993 DOI: 10.3390/ijms21031095] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2020] [Revised: 02/04/2020] [Accepted: 02/04/2020] [Indexed: 12/18/2022] Open
Abstract
The arteriosclerosis-dependent alteration of brain perfusion is one of the major determinants in small vessel disease, since small vessels have a pivotal role in the brain's autoregulation. Nevertheless, as far as we know, endothelium distress can potentiate the flow dysregulation and lead to subcortical vascular dementia that is related to small vessel disease (SVD), also being defined as subcortical vascular dementia (sVAD), as well as microglia activation, chronic hypoxia and hypoperfusion, vessel-tone dysregulation, altered astrocytes, and pericytes functioning blood-brain barrier disruption. The molecular basis of this pathology remains controversial. The apparent consequence (or a first event, too) is the macroscopic alteration of the neurovascular coupling. Here, we examined the possible mechanisms that lead a healthy aging process towards subcortical dementia. We remarked that SVD and white matter abnormalities related to age could be accelerated and potentiated by different vascular risk factors. Vascular function changes can be heavily influenced by genetic and epigenetic factors, which are, to the best of our knowledge, mostly unknown. Metabolic demands, active neurovascular coupling, correct glymphatic process, and adequate oxidative and inflammatory responses could be bulwarks in defense of the correct aging process; their impairments lead to a potentially catastrophic and non-reversible condition.
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Affiliation(s)
- Rita Moretti
- Neurology Clinic, Department of Medical, Surgical and Health Sciences, University of Trieste, 34149 Trieste, Italy;
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Nickolls AR, Bönnemann CG. The roles of dystroglycan in the nervous system: insights from animal models of muscular dystrophy. Dis Model Mech 2018; 11:11/12/dmm035931. [PMID: 30578246 PMCID: PMC6307911 DOI: 10.1242/dmm.035931] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Dystroglycan is a cell membrane protein that binds to the extracellular matrix in a variety of mammalian tissues. The α-subunit of dystroglycan (αDG) is heavily glycosylated, including a special O-mannosyl glycoepitope, relying upon this unique glycosylation to bind its matrix ligands. A distinct group of muscular dystrophies results from specific hypoglycosylation of αDG, and they are frequently associated with central nervous system involvement, ranging from profound brain malformation to intellectual disability without evident morphological defects. There is an expanding literature addressing the function of αDG in the nervous system, with recent reports demonstrating important roles in brain development and in the maintenance of neuronal synapses. Much of these data are derived from an increasingly rich array of experimental animal models. This Review aims to synthesize the information from such diverse models, formulating an up-to-date understanding about the various functions of αDG in neurons and glia of the central and peripheral nervous systems. Where possible, we integrate these data with our knowledge of the human disorders to promote translation from basic mechanistic findings to clinical therapies that take the neural phenotypes into account. Summary: Dystroglycan is a ubiquitous matrix receptor linked to brain and muscle disease. Unraveling the functions of this protein will inform basic and translational research on neural development and muscular dystrophies.
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Affiliation(s)
- Alec R Nickolls
- National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA.,Department of Neuroscience, Brown University, Providence, RI 02912, USA
| | - Carsten G Bönnemann
- National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA
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14
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Norepinephrine induces rapid and long-lasting phosphorylation and redistribution of connexin 43 in cortical astrocytes. Biochem Biophys Res Commun 2018; 504:690-697. [DOI: 10.1016/j.bbrc.2018.09.021] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2018] [Accepted: 09/05/2018] [Indexed: 11/21/2022]
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15
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Kraner SD, Norris CM. Astrocyte Activation and the Calcineurin/NFAT Pathway in Cerebrovascular Disease. Front Aging Neurosci 2018; 10:287. [PMID: 30297999 PMCID: PMC6160594 DOI: 10.3389/fnagi.2018.00287] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2018] [Accepted: 09/03/2018] [Indexed: 12/27/2022] Open
Abstract
Calcineurin (CN) is a Ca2+/calmodulin-dependent protein phosphatase with high abundance in nervous tissue. Though enriched in neurons, CN can become strongly induced in subsets of activated astrocytes under different pathological conditions where it interacts extensively with the nuclear factor of activated T cells (NFATs). Recent work has shown that regions of small vessel damage are associated with the upregulation of a proteolized, highly active form of CN in nearby astrocytes, suggesting a link between the CN/NFAT pathway and chronic cerebrovascular disease. In this Mini Review article, we discuss CN/NFAT signaling properties in the context of vascular disease and use previous cell type-specific intervention studies in Alzheimer's disease and traumatic brain injury models as a framework to understand how astrocytic CN/NFATs may couple vascular pathology to neurodegeneration and cognitive loss.
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Affiliation(s)
- Susan D. Kraner
- Sanders-Brown Center on Aging, University of Kentucky College of Medicine, Lexington, KY, United States
| | - Christopher M. Norris
- Sanders-Brown Center on Aging, University of Kentucky College of Medicine, Lexington, KY, United States
- Department of Pharmacology and Nutritional Sciences, University of Kentucky College of Medicine, Lexington, KY, United States
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16
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Gorlewicz A, Kaczmarek L. Pathophysiology of Trans-Synaptic Adhesion Molecules: Implications for Epilepsy. Front Cell Dev Biol 2018; 6:119. [PMID: 30298130 PMCID: PMC6160742 DOI: 10.3389/fcell.2018.00119] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2018] [Accepted: 08/30/2018] [Indexed: 12/31/2022] Open
Abstract
Chemical synapses are specialized interfaces between neurons in the brain that transmit and modulate information, thereby integrating cells into multiplicity of interacting neural circuits. Cell adhesion molecules (CAMs) might form trans-synaptic complexes that are crucial for the appropriate identification of synaptic partners and further for the establishment, properties, and dynamics of synapses. When affected, trans-synaptic adhesion mechanisms play a role in synaptopathies in a variety of neuropsychiatric disorders including epilepsy. This review recapitulates current understanding of trans-synaptic interactions in pathophysiology of interneuronal connections. In particular, we discuss here the possible implications of trans-synaptic adhesion dysfunction for epilepsy.
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Affiliation(s)
- Adam Gorlewicz
- Laboratory of Neurobiology, Nencki Institute of Experimental Biology, Polish Academy of Sciences, Warsaw, Poland
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Jian WX, Zhang Z, Chu SF, Peng Y, Chen NH. Potential roles of brain barrier dysfunctions in the early stage of Alzheimer’s disease. Brain Res Bull 2018; 142:360-367. [DOI: 10.1016/j.brainresbull.2018.08.012] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2018] [Revised: 08/03/2018] [Accepted: 08/17/2018] [Indexed: 02/07/2023]
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18
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Nuriya M, Yasui D, Yamada T, Aoki T, Yasui M. Direct posttranslational modification of astrocytic connexin 43 proteins by the general anesthetic propofol in the cerebral cortex. Biochem Biophys Res Commun 2018; 497:734-741. [DOI: 10.1016/j.bbrc.2018.02.142] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2018] [Accepted: 02/16/2018] [Indexed: 10/18/2022]
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Price BR, Norris CM, Sompol P, Wilcock DM. An emerging role of astrocytes in vascular contributions to cognitive impairment and dementia. J Neurochem 2018; 144:644-650. [PMID: 29222909 DOI: 10.1111/jnc.14273] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2017] [Revised: 10/30/2017] [Accepted: 11/23/2017] [Indexed: 01/15/2023]
Abstract
Vascular contributions to cognitive impairment and dementia (VCID) is understood to be the second most common cause of dementia after Alzheimer's disease, and is also a frequent comorbidity with Alzheimer's disease. While VCID is widely acknowledged as a key contributor to dementia, the mechanistic underpinnings of VCID remain poorly understood. In this review, we address the potential role of astrocytes in the pathophysiology of VCID. The vast majority of the blood vessels in the brain are surrounded by astrocytic end-feet. Given that astrocytes make up a significant proportion of the cells in the brain, and that astrocytes are usually passively connected to one another through gap junctions, we hypothesize that astrocytes are key mediators of cognitive impairment because of cerebrovascular disease. In this review, we discuss the existing body of literature regarding the role of astrocytes at the vasculature in the brain, and the known consequences of their dysfunction, as well as our hypotheses regarding the role astrocytes play in VCID. This article is part of the Special Issue "Vascular Dementia".
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Affiliation(s)
- Brittani R Price
- Department of Physiology, Sanders-Brown Center on Aging, University of Kentucky, Lexington, Kentucky, USA
| | - Christopher M Norris
- Department of Pharmacology and Nutritional Sciences, University of Kentucky, Lexington, Kentucky, USA
| | - Pradoldej Sompol
- Department of Pharmacology and Nutritional Sciences, University of Kentucky, Lexington, Kentucky, USA
| | - Donna M Wilcock
- Department of Physiology, Sanders-Brown Center on Aging, University of Kentucky, Lexington, Kentucky, USA
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Time-course of glial changes in the hyperhomocysteinemia model of vascular cognitive impairment and dementia (VCID). Neuroscience 2016; 341:42-51. [PMID: 27890830 DOI: 10.1016/j.neuroscience.2016.11.024] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2016] [Revised: 11/10/2016] [Accepted: 11/17/2016] [Indexed: 12/31/2022]
Abstract
Vascular cognitive impairment and dementia (VCID) is the second leading cause of dementia behind Alzheimer's disease (AD) and is a frequent co-morbidity with AD. Despite its prevalence, little is known about the molecular mechanisms underlying the cognitive dysfunction resulting from cerebrovascular disease. Astrocytic end-feet almost completely surround intraparenchymal blood vessels in the brain and express a variety of channels and markers indicative of their specialized functions in the maintenance of ionic and osmotic homeostasis and gliovascular signaling. These functions are mediated by end-foot enrichment of the aquaporin 4 water channel (AQP4), the inward rectifying potassium channel Kir4.1 and the calcium-dependent potassium channel MaxiK. Using our hyperhomocysteinemia (HHcy) model of VCID we examined the time-course of astrocytic end-foot changes along with cognitive and neuroinflammatory outcomes. We found that there were significant astrocytic end-foot disruptions in the HHcy model. AQP4 becomes dislocalized from the end-feet, there is a loss of Kir4.1 and MaxiK protein expression, as well as a loss of the Dp71 protein known to anchor the Kir4.1, MaxiK and AQP4 channels to the end-foot membrane. Neuroinflammation occurs prior to the astrocytic changes, while cognitive impairment continues to decline with the exacerbation of the astrocytic changes. We have previously reported similar astrocytic changes in models of cerebral amyloid angiopathy (CAA) and therefore, we believe astrocytic end-foot disruption could represent a common cellular mechanism of VCID and may be a target for therapeutic development.
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Effect of delta opioid receptor activation on spatial cognition and neurogenesis in cerebral ischemic rats. Neurosci Lett 2016; 620:20-6. [DOI: 10.1016/j.neulet.2016.03.035] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2016] [Revised: 03/14/2016] [Accepted: 03/21/2016] [Indexed: 01/14/2023]
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β-Dystroglycan cleavage by matrix metalloproteinase-2/-9 disturbs aquaporin-4 polarization and influences brain edema in acute cerebral ischemia. Neuroscience 2016; 326:141-157. [PMID: 27038751 DOI: 10.1016/j.neuroscience.2016.03.055] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2015] [Revised: 03/19/2016] [Accepted: 03/23/2016] [Indexed: 01/31/2023]
Abstract
Dystroglycan (DG) is widely expressed in various tissues, and throughout the cerebral microvasculature. It consists of two subunits, α-DG and β-DG, and the cleavage of the latter by matrix metalloproteinase (MMP)-2 and -9 underlies a number of physiological and pathological processes. However, the involvement of MMP-2/-9-mediated β-DG cleavage in cerebral ischemia remains uncertain. In astrocytes, DG is crucial for maintaining the polarization of aquaporin-4 (AQP4), which plays a role in the regulation of cytotoxic and vasogenic edema. The present study aimed to explore the effects of MMP-2/-9-mediated β-DG cleavage on AQP4 polarization and brain edema in acute cerebral ischemia. A model of cerebral ischemia was established via permanent middle cerebral artery occlusion (pMCAO) in male C57BL/6 mice. Western blotting, real-time polymerase chain reaction (PCR), immunohistochemical staining, immunofluorescent staining, electron microscopy, and light microscopy were used. Captopril was applied as a selective MMP-2/-9 inhibitor. Recombinant mouse MMP (rmMMP)-2 and -9 were used in an in vitro cleavage experiment. The present study demonstrated evidence of β-DG cleavage by MMP-2/-9 in pMCAO mouse brains; this cleavage was implicated in AQP4 redistribution and brain edema in cerebral ischemia. In addition, captopril exacerbated cytotoxic edema and ameliorated vasogenic edema at 24h after pMCAO, and alleviated brain edema and neurological deficit at 48h and 72h. In conclusion, this study provides novel insight into the effects of MMP-2/-9-mediated β-DG cleavage in acute cerebral ischemia. Such findings might facilitate the development of a therapeutic strategy for the optimization of MMP-2/-9 targeted treatment in cerebral ischemia.
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Recombinant Human Erythropoietin Protects Myocardial Cells from Apoptosis via the Janus-Activated Kinase 2/Signal Transducer and Activator of Transcription 5 Pathway in Rats with Epilepsy. Curr Ther Res Clin Exp 2015; 77:90-8. [PMID: 26649078 PMCID: PMC4644243 DOI: 10.1016/j.curtheres.2015.07.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/28/2015] [Indexed: 12/19/2022] Open
Abstract
OBJECTIVE To investigate the potential mechanisms underlying the protective effects of recombinant human erythropoietin (rhEPO) and carbamylated EPO (CEPO) against myocardial cell apoptosis in epilepsy. METHODS Rats were given an intra-amygdala injection of kainic acid to induce epilepsy. Groups of rats were treated with rhEPO or CEPO before induction of epilepsy, whereas additional rats were given a caudal vein injection of AG490, a selective inhibitor of Janus kinase 2 (JAK2). At different time points after seizure onset, electroencephalogram changes were recorded, and myocardium samples were taken for the detection of myocardial cell apoptosis and expression of JAK2, signal transducer and activator of transcription 5 (STAT5), caspase-3, and bcl-xl mRNAs and proteins. RESULTS Induction of epilepsy significantly enhanced myocardial cell apoptosis and upregulated the expression of caspase-3 and bcl-xl proteins and JAK2 and STAT5a at both the mRNA and protein levels. Pretreatment with either rhEPO or CEPO reduced the number of apoptotic cells, upregulated bcl-xl expression, and downregulated caspase-3 expression in the myocardium of epileptic rats. Both myocardial JAK2 and STAT5a mRNAs, as well as phosphorylated species of JAK2 and STAT5a, were upregulated in epileptic rats in response to rhEPO-but not to CEPO-pretreatment. AG490 treatment increased apoptosis, upregulated caspase-3 protein expression, and downregulated bcl-xl protein expression in the myocardium of epileptic rats. CONCLUSIONS These results indicate that myocardial cell apoptosis may contribute to myocardial injury in epilepsy. EPO protects myocardial cells from apoptosis via the JAK2/STAT5 pathway in rats with experimental epilepsy, whereas CEPO exerts antiapoptotic activity perhaps via a pathway independent of JAK2/STAT5 signaling.
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Nuriya M. [Astrovascular interaction]. Nihon Yakurigaku Zasshi 2015; 145:326-8. [PMID: 26063156 DOI: 10.1254/fpj.145.326] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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