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Mayo F, González-Vinceiro L, Hiraldo-González L, Rodríguez-Gómez FD, Calle-Castillejo C, Mayo M, Netti V, Ramírez-Lorca R, Echevarría M. Impact of aquaporin-4 and CD11c + microglia in the development of ependymal cells in the aqueduct: inferences to hydrocephalus. Fluids Barriers CNS 2024; 21:53. [PMID: 38956598 PMCID: PMC11221146 DOI: 10.1186/s12987-024-00548-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2023] [Accepted: 05/07/2024] [Indexed: 07/04/2024] Open
Abstract
AQP4 is expressed in the endfeet membranes of subpial and perivascular astrocytes and in the ependymal cells that line the ventricular system. The sporadic appearance of obstructive congenital hydrocephalus (OCHC) has been observed in the offspring of AQP4-/- mice (KO) due to stenosis of Silvio's aqueduct. Here, we explore whether the lack of AQP4 expression leads to abnormal development of ependymal cells in the aqueduct of mice. We compared periaqueductal samples from wild-type and KO mice. The microarray-based transcriptome analysis reflected a large number of genes with differential expression (809). Gene sets (GS) associated with ependymal development, ciliary function and the immune system were specially modified qPCR confirmed reduced expression in the KO mice genes: (i) coding for transcription factors for ependymal differentiation (Rfx4 and FoxJ1), (ii) involved in the constitution of the central apparatus of the axoneme (Spag16 and Hydin), (iii) associated with ciliary assembly (Cfap43, Cfap69 and Ccdc170), and (iv) involved in intercellular junction complexes of the ependyma (Cdhr4). By contrast, genes such as Spp1, Gpnmb, Itgax, and Cd68, associated with a Cd11c-positive microglial population, were overexpressed in the KO mice. Electron microscopy and Immunofluorescence of vimentin and γ-tubulin revealed a disorganized ependyma in the KO mice, with changes in the intercellular complex union, unevenly orientated cilia, and variations in the planar cell polarity of the apical membrane. These structural alterations translate into reduced cilia beat frequency, which might alter cerebrospinal fluid movement. The presence of CD11c + microglia cells in the periaqueductal zone of mice during the first postnatal week is a novel finding. In AQP4-/- mice, these cells remain present around the aqueduct for an extended period, showing peak expression at P11. We propose that these cells play an important role in the normal development of the ependyma and that their overexpression in KO mice is crucial to reduce ependyma abnormalities that could otherwise contribute to the development of obstructive hydrocephalus.
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Affiliation(s)
- Francisco Mayo
- Instituto de Biomedicina de Sevilla, IBiS/Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Av. Manuel Siurot s/n, 41013, Seville, Spain
- Departamento de Fisiología Médica y Biofísica, Facultad de Medicina, Universidad de Sevilla, 41009, Seville, Spain
| | - Lourdes González-Vinceiro
- Instituto de Biomedicina de Sevilla, IBiS/Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Av. Manuel Siurot s/n, 41013, Seville, Spain
- Departamento de Fisiología Médica y Biofísica, Facultad de Medicina, Universidad de Sevilla, 41009, Seville, Spain
| | - Laura Hiraldo-González
- Instituto de Biomedicina de Sevilla, IBiS/Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Av. Manuel Siurot s/n, 41013, Seville, Spain
- Departamento de Fisiología Médica y Biofísica, Facultad de Medicina, Universidad de Sevilla, 41009, Seville, Spain
| | - Francisco D Rodríguez-Gómez
- Instituto de Biomedicina de Sevilla, IBiS/Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Av. Manuel Siurot s/n, 41013, Seville, Spain
| | - Claudia Calle-Castillejo
- Instituto de Biomedicina de Sevilla, IBiS/Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Av. Manuel Siurot s/n, 41013, Seville, Spain
| | - Manuel Mayo
- Física Teórica, Universidad de Sevilla, Apartado de Correos 1065, 41080, Seville, Spain
| | - Vanina Netti
- Facultad de Medicina, Departamento de Ciencias Fisiológicas, Laboratorio de Biomembranas, Universidad de Buenos Aires- CONICET, Instituto de Fisiología y Biofísica ''Bernardo Houssay'' (IFIBIO-HOUSSAY), Buenos Aires, Argentina
| | - Reposo Ramírez-Lorca
- Instituto de Biomedicina de Sevilla, IBiS/Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Av. Manuel Siurot s/n, 41013, Seville, Spain
- Departamento de Fisiología Médica y Biofísica, Facultad de Medicina, Universidad de Sevilla, 41009, Seville, Spain
| | - Miriam Echevarría
- Instituto de Biomedicina de Sevilla, IBiS/Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Av. Manuel Siurot s/n, 41013, Seville, Spain.
- Departamento de Fisiología Médica y Biofísica, Facultad de Medicina, Universidad de Sevilla, 41009, Seville, Spain.
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2
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Li J, Jia S, Song Y, Xu W, Lin J. Ginkgolide B can alleviate spinal cord glymphatic system dysfunction and provide neuroprotection in painful diabetic neuropathy rats by inhibiting matrix metalloproteinase-9. Neuropharmacology 2024; 250:109907. [PMID: 38492884 DOI: 10.1016/j.neuropharm.2024.109907] [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: 12/12/2023] [Revised: 03/02/2024] [Accepted: 03/10/2024] [Indexed: 03/18/2024]
Abstract
The glymphatic system plays a crucial role in maintaining optimal central nervous system (CNS) function by facilitating the removal of metabolic wastes. Aquaporin-4 (AQP4) protein, predominantly located on astrocyte end-feet, is a key pathway for metabolic waste excretion. β-Dystroglycan (β-DG) can anchor AQP4 protein to the end-feet membrane of astrocytes and can be cleaved by matrix metalloproteinase (MMP)-9 protein. Studies have demonstrated that hyperglycemia upregulates MMP-9 expression in the nervous system, leading to neuropathic pain. Ginkgolide B (GB) exerts an inhibitory effect on the MMP-9 protein. In this study, we investigated whether inhibition of MMP-9-mediated β-DG cleavage by GB is involved in the regulation of AQP4 polarity within the glymphatic system in painful diabetic neuropathy (PDN) and exerts neuroprotective effects. The PDN model was established by injecting streptozotocin (STZ). Functional changes in the glymphatic system were observed using magnetic resonance imaging (MRI). The paw withdrawal threshold (PWT) was measured to assess mechanical allodynia. The protein expressions of MMP-9, β-DG, and AQP4 were detected by Western blotting and immunofluorescence. Our findings revealed significant decreases in the efficiency of contrast agent clearance within the spinal glymphatic system of the rats, accompanied by decreased PWT, increased MMP-9 protein expression, decreased β-DG protein expression, and loss of AQP4 polarity. Notably, GB treatment demonstrated the capacity to ameliorate spinal cord glymphatic function by modulating AQP4 polarity through MMP-9 inhibition, offering a promising therapeutic avenue for PDN.
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Affiliation(s)
- Jiang Li
- Department of Anesthesiology, The Affiliated Hospital of North Sichuan Medical College, Nanchong, China.
| | - Shuaiying Jia
- Department of Anesthesiology, The Affiliated Hospital of North Sichuan Medical College, Nanchong, China.
| | | | - Wenmei Xu
- Department of Anesthesiology, The Affiliated Hospital of North Sichuan Medical College, Nanchong, China.
| | - Jingyan Lin
- Department of Anesthesiology, The Affiliated Hospital of North Sichuan Medical College, Nanchong, China.
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3
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Yuan Y, Peng W, Lei J, Zhao Y, Zhao B, Li Y, Wang J, Qu Q. AQP4 Endocytosis-Lysosome Degradation Mediated by MMP-9/β-DG Involved in Diabetes Cognitive Impairment. Mol Neurobiol 2024:10.1007/s12035-024-04085-9. [PMID: 38512439 DOI: 10.1007/s12035-024-04085-9] [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: 11/23/2023] [Accepted: 02/29/2024] [Indexed: 03/23/2024]
Abstract
Cognitive impairment is considered to be one of the important comorbidities of diabetes, but the underlying mechanisms are widely unknown. Aquaporin-4 (AQP4) is the most abundant water channel in the central nervous system, which plays a neuroprotective role in various neurological diseases by maintaining the function of glymphatic system and synaptic plasticity. However, whether AQP4 is involved in diabetes-related cognitive impairment remains unknown. β-dystroglycan (β-DG), a key molecule for anchoring AQP4 on the plasma membrane of astrocytes and avoiding its targeting to lysosomes for degradation, can be cleaved by matrix metalloproteinase-9 (MMP-9). β-DG deficiency can cause a decline in AQP4 via regulating its endocytosis. However, whether cleavage of β-DG can affect the expression of AQP4 remains unreported. In this study, we observed that diabetes mice displayed cognitive disorder accompanied by reduction of AQP4 in prefrontal cortex. And we found that bafilomycin A1, a widely used lysosome inhibitor, could reverse the downregulation of AQP4 in diabetes, further demonstrating that the reduction of AQP4 in diabetes is a result of more endocytosis-lysosome degradation. In further experiments, we found diabetes caused the excessive activation of MMP-9/β-DG which leaded to the loss of connection between AQP4 and β-DG, further inducing the endocytosis of AQP4. Moreover, inhibition of MMP-9/β-DG restored the endocytosis-lysosome degradation of AQP4 and partially alleviated cognitive dysfunction in diabetes. Our study sheds new light on the role of AQP4 in diabetes-associated cognitive disorder. And we provide a promising therapeutic target to reverse the endocytosis-lysosome degradation of AQP4 in diabetes, such as MMP-9/β-DG.
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Affiliation(s)
- Ye Yuan
- Department of Neurology, The First Affiliated Hospital of Xi'an Jiaotong University, 277 West Yanta Rd, Xi'an, 710061, China
| | - Wei Peng
- Department of Neurology, The First Affiliated Hospital of Xi'an Jiaotong University, 277 West Yanta Rd, Xi'an, 710061, China
| | - Jingna Lei
- Department of Neurology, The First Affiliated Hospital of Xi'an Jiaotong University, 277 West Yanta Rd, Xi'an, 710061, China
| | - Yi Zhao
- Department of Neurology, The First Affiliated Hospital of Xi'an Jiaotong University, 277 West Yanta Rd, Xi'an, 710061, China
| | - Beiyu Zhao
- Department of Neurology, The First Affiliated Hospital of Xi'an Jiaotong University, 277 West Yanta Rd, Xi'an, 710061, China
| | - Yan Li
- Center for Brain Science, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, China
| | - Jin Wang
- Department of Neurology, The First Affiliated Hospital of Xi'an Jiaotong University, 277 West Yanta Rd, Xi'an, 710061, China.
| | - Qiumin Qu
- Department of Neurology, The First Affiliated Hospital of Xi'an Jiaotong University, 277 West Yanta Rd, Xi'an, 710061, China.
- Center for Brain Science, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, China.
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4
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Markou A, Kitchen P, Aldabbagh A, Repici M, Salman MM, Bill RM, Balklava Z. Mechanisms of aquaporin-4 vesicular trafficking in mammalian cells. J Neurochem 2024; 168:100-114. [PMID: 38102893 PMCID: PMC10953025 DOI: 10.1111/jnc.16029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Revised: 11/24/2023] [Accepted: 12/02/2023] [Indexed: 12/17/2023]
Abstract
The aquaporin-4 (AQP4) water channel is abundantly expressed in the glial cells of the central nervous system and facilitates brain swelling following diverse insults, such as traumatic injury or stroke. Lack of specific and therapeutic AQP4 inhibitors highlights the need to explore alternative routes to control the water permeability of glial cell membranes. The cell surface abundance of AQP4 in mammalian cells fluctuates rapidly in response to changes in oxygen levels and tonicity, suggesting a role for vesicular trafficking in its translocation to and from the cell surface. However, the molecular mechanisms of AQP4 trafficking are not fully elucidated. In this work, early and recycling endosomes were investigated as likely candidates of rapid AQP4 translocation together with changes in cytoskeletal dynamics. In transiently transfected HEK293 cells a significant amount of AQP-eGFP colocalised with mCherry-Rab5-positive early endosomes and mCherry-Rab11-positive recycling endosomes. When exposed to hypotonic conditions, AQP4-eGFP rapidly translocated from intracellular vesicles to the cell surface. Co-expression of dominant negative forms of the mCherry-Rab5 and -Rab11 with AQP4-eGFP prevented hypotonicity-induced AQP4-eGFP trafficking and led to concentration at the cell surface or intracellular vesicles respectively. Use of endocytosis inhibiting drugs indicated that AQP4 internalisation was dynamin-dependent. Cytoskeleton dynamics-modifying drugs also affected AQP4 translocation to and from the cell surface. AQP4 trafficking mechanisms were validated in primary human astrocytes, which express high levels of endogenous AQP4. The results highlight the role of early and recycling endosomes and cytoskeletal dynamics in AQP4 translocation in response to hypotonic and hypoxic stress and suggest continuous cycling of AQP4 between intracellular vesicles and the cell surface under physiological conditions.
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Affiliation(s)
- Andrea Markou
- College of Health and Life SciencesAston UniversityBirminghamUK
- School of Biosciences, Faculty of Health and Medical SciencesUniversity of SurreyGuildfordUK
| | - Philip Kitchen
- College of Health and Life SciencesAston UniversityBirminghamUK
| | - Ahmed Aldabbagh
- College of Health and Life SciencesAston UniversityBirminghamUK
| | | | - Mootaz M. Salman
- Department of Physiology, Anatomy and GeneticsUniversity of OxfordOxfordUK
- Kavli Institute for NanoScience DiscoveryUniversity of OxfordOxfordUK
| | - Roslyn M. Bill
- College of Health and Life SciencesAston UniversityBirminghamUK
| | - Zita Balklava
- College of Health and Life SciencesAston UniversityBirminghamUK
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5
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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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6
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Mayo F, González-Vinceiro L, Hiraldo-González L, Calle-Castillejo C, Morales-Alvarez S, Ramírez-Lorca R, Echevarría M. Aquaporin-4 Expression Switches from White to Gray Matter Regions during Postnatal Development of the Central Nervous System. Int J Mol Sci 2023; 24:3048. [PMID: 36769371 PMCID: PMC9917791 DOI: 10.3390/ijms24033048] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2023] [Revised: 01/24/2023] [Accepted: 01/31/2023] [Indexed: 02/09/2023] Open
Abstract
Aquaporin-4 (AQP4) is the most abundant water channel in the central nervous system and plays a fundamental role in maintaining water homeostasis there. In adult mice, AQP4 is located mainly in ependymal cells, in the endfeet of perivascular astrocytes, and in the glia limitans. Meanwhile, its expression, location, and function throughout postnatal development remain largely unknown. Here, the expression of AQP4 mRNA was studied by in situ hybridization and RT-qPCR, and the localization and amount of protein was studied by immunofluorescence and western blotting, both in the brain and spinal cord. For this, wild-type mice of the C57BL/6 line, aged 1, 3, 7, 11, 20, and 60 days, and 18 months were used. The results showed a change in both the expression and location of AQP4 in postnatal development compared to those during adult life. In the early stages of postnatal development it appears in highly myelinated areas, such as the corpus callosum or cerebellum, and as the animal grows, it disappears from these areas, passing through the cortical regions of the forebrain and concentrating around the blood vessels. These findings suggest an unprecedented possible role for AQP4 in the early cell differentiation process, during the first days of life in the newborn animal, which will lead to myelination.
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Affiliation(s)
- Francisco Mayo
- Institute of Biomedicine of Seville (IBiS), Virgen del Rocío University Hospital, (HUVR)/Spanish National Research Council (CSIC)/University of Seville, 41013 Seville, Spain
- Department of Physiology and Biophysics, University of Seville, 41009 Seville, Spain
| | - Lourdes González-Vinceiro
- Institute of Biomedicine of Seville (IBiS), Virgen del Rocío University Hospital, (HUVR)/Spanish National Research Council (CSIC)/University of Seville, 41013 Seville, Spain
- Department of Physiology and Biophysics, University of Seville, 41009 Seville, Spain
| | - Laura Hiraldo-González
- Institute of Biomedicine of Seville (IBiS), Virgen del Rocío University Hospital, (HUVR)/Spanish National Research Council (CSIC)/University of Seville, 41013 Seville, Spain
- Department of Physiology and Biophysics, University of Seville, 41009 Seville, Spain
| | - Claudia Calle-Castillejo
- Institute of Biomedicine of Seville (IBiS), Virgen del Rocío University Hospital, (HUVR)/Spanish National Research Council (CSIC)/University of Seville, 41013 Seville, Spain
| | - Sara Morales-Alvarez
- Institute of Biomedicine of Seville (IBiS), Virgen del Rocío University Hospital, (HUVR)/Spanish National Research Council (CSIC)/University of Seville, 41013 Seville, Spain
| | - Reposo Ramírez-Lorca
- Institute of Biomedicine of Seville (IBiS), Virgen del Rocío University Hospital, (HUVR)/Spanish National Research Council (CSIC)/University of Seville, 41013 Seville, Spain
- Department of Physiology and Biophysics, University of Seville, 41009 Seville, Spain
| | - Miriam Echevarría
- Institute of Biomedicine of Seville (IBiS), Virgen del Rocío University Hospital, (HUVR)/Spanish National Research Council (CSIC)/University of Seville, 41013 Seville, Spain
- Department of Physiology and Biophysics, University of Seville, 41009 Seville, Spain
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7
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Allnoch L, Leitzen E, Zdora I, Baumgärtner W, Hansmann F. Astrocyte depletion alters extracellular matrix composition in the demyelinating phase of Theiler's murine encephalomyelitis. PLoS One 2022; 17:e0270239. [PMID: 35714111 PMCID: PMC9205503 DOI: 10.1371/journal.pone.0270239] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2022] [Accepted: 06/07/2022] [Indexed: 12/14/2022] Open
Abstract
Astrocytes produce extracellular matrix (ECM) glycoproteins contributing to the blood-brain barrier and regulating the immune response in the central nervous system (CNS). The aim of this study was to investigate the impact of astrocyte depletion upon the clinical outcome and the composition of ECM glycoproteins in a virus-induced animal model of demyelination. Glial fibrillary acidic protein (GFAP)-thymidine-kinase transgenic SJL (GFAP-knockout) and wildtype mice were infected with Theiler’s murine encephalomyelitis virus (TMEV). Astrocyte depletion was induced during the progressive, demyelinating disease phase by ganciclovir administration once daily between 56 and 77 days post infection (dpi). At 77 dpi GFAP-knockout mice showed a significant deterioration of clinical signs associated with a reduction of azan and picrosirius red stained ECM-molecules in the thoracic spinal cord. Basement-membrane-associated ECM-molecules including laminin, entactin/nidogen-1 and Kir4.1 as well as non-basement membrane-associated ECM-molecules like collagen I, decorin, tenascin-R and CD44 were significantly reduced in the spinal cord of GFAP-knockout mice. The reduction of the investigated ECM-molecules demonstrates that astrocytes play a key role in the production of ECM-molecules. The present findings indicate that the detected loss of Kir4.1 and CD44 as well as the disruption of the integrity of perineuronal nets led to the deterioration of clinical signs in GFAP-knockout mice.
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Affiliation(s)
- Lisa Allnoch
- Department of Pathology, University of Veterinary Medicine Hannover, Hannover, Germany
- Center for Systems Neuroscience, Hannover, Germany
| | - Eva Leitzen
- Department of Pathology, University of Veterinary Medicine Hannover, Hannover, Germany
| | - Isabel Zdora
- Department of Pathology, University of Veterinary Medicine Hannover, Hannover, Germany
- Center for Systems Neuroscience, Hannover, Germany
| | - Wolfgang Baumgärtner
- Department of Pathology, University of Veterinary Medicine Hannover, Hannover, Germany
- Center for Systems Neuroscience, Hannover, Germany
- * E-mail:
| | - Florian Hansmann
- Department of Pathology, University of Veterinary Medicine Hannover, Hannover, Germany
- Center for Systems Neuroscience, Hannover, Germany
- Institute for Veterinary Pathology, Veterinary Faculty, Leipzig University, Leipzig, Germany
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8
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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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9
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Markou A, Unger L, Abir-Awan M, Saadallah A, Halsey A, Balklava Z, Conner M, Törnroth-Horsefield S, Greenhill SD, Conner A, Bill RM, Salman MM, Kitchen P. Molecular mechanisms governing aquaporin relocalisation. BIOCHIMICA ET BIOPHYSICA ACTA. BIOMEMBRANES 2022; 1864:183853. [PMID: 34973181 PMCID: PMC8825993 DOI: 10.1016/j.bbamem.2021.183853] [Citation(s) in RCA: 42] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Revised: 12/20/2021] [Accepted: 12/21/2021] [Indexed: 02/07/2023]
Abstract
The aquaporins (AQPs) form a family of integral membrane proteins that facilitate the movement of water across biological membrane by osmosis, as well as facilitating the diffusion of small polar solutes. AQPs have been recognised as drug targets for a variety of disorders associated with disrupted water or solute transport, including brain oedema following stroke or trauma, epilepsy, cancer cell migration and tumour angiogenesis, metabolic disorders, and inflammation. Despite this, drug discovery for AQPs has made little progress due to a lack of reproducible high-throughput assays and difficulties with the druggability of AQP proteins. However, recent studies have suggested that targetting the trafficking of AQP proteins to the plasma membrane is a viable alternative drug target to direct inhibition of the water-conducting pore. Here we review the literature on the trafficking of mammalian AQPs with a view to highlighting potential new drug targets for a variety of conditions associated with disrupted water and solute homeostasis.
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Affiliation(s)
- Andrea Markou
- College of Health and Life Sciences, Aston University, Aston Triangle, Birmingham B4 7ET, UK
| | - Lucas Unger
- College of Health and Life Sciences, Aston University, Aston Triangle, Birmingham B4 7ET, UK
| | - Mohammed Abir-Awan
- College of Health and Life Sciences, Aston University, Aston Triangle, Birmingham B4 7ET, UK
| | - Ahmed Saadallah
- College of Health and Life Sciences, Aston University, Aston Triangle, Birmingham B4 7ET, UK
| | - Andrea Halsey
- MRC Institute of Metabolic Science, University of Cambridge, Cambridge CB2 0QQ, UK
| | - Zita Balklava
- College of Health and Life Sciences, Aston University, Aston Triangle, Birmingham B4 7ET, UK
| | - Matthew Conner
- School of Sciences, Research Institute in Healthcare Science, University of Wolverhampton, Wolverhampton WV1 1LY, UK
| | | | - Stuart D Greenhill
- College of Health and Life Sciences, Aston University, Aston Triangle, Birmingham B4 7ET, UK
| | - Alex Conner
- Institute of Clinical Sciences, College of Medical and Dental Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
| | - Roslyn M Bill
- College of Health and Life Sciences, Aston University, Aston Triangle, Birmingham B4 7ET, UK
| | - Mootaz M Salman
- Department of Physiology Anatomy and Genetics, University of Oxford, Oxford OX1 3QX, UK; Oxford Parkinson's Disease Centre, University of Oxford, South Parks Road, Oxford OX1 3QX, UK.
| | - Philip Kitchen
- College of Health and Life Sciences, Aston University, Aston Triangle, Birmingham B4 7ET, UK.
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10
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Cellular Distribution of Brain Aquaporins and Their Contribution to Cerebrospinal Fluid Homeostasis and Hydrocephalus. Biomolecules 2022; 12:biom12040530. [PMID: 35454119 PMCID: PMC9025855 DOI: 10.3390/biom12040530] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2022] [Revised: 03/28/2022] [Accepted: 03/30/2022] [Indexed: 01/19/2023] Open
Abstract
Brain aquaporins facilitate the movement of water between the four water compartments: blood, cerebrospinal fluid, interstitial fluid, and intracellular fluid. This work analyzes the expression of the four most abundant aquaporins (AQPs) (AQP1, AQP4, AQP9, and AQP11) in the brains of mice and discuss their contribution to hydrocephalus. We analyzed available data from single-cell RNA sequencing of the central nervous system of mice to describe the expression of aquaporins and compare their distribution with that based on qPCR, western blot, and immunohistochemistry assays. Expression of AQP1 in the apical cell membrane of choroid plexus epithelial cells and of AQP4 in ependymal cells, glia limitans, and astrocyte processes in the pericapillary end foot is consistent with the involvement of both proteins in cerebrospinal fluid homeostasis. The expression of both aquaporins compensates for experimentally induced hydrocephalus in the animals. Recent data demonstrate that hypoxia in aged animals alters AQP4 expression in the choroidal plexus and cortex, increasing the ventricle size and intraventricular pressure. Cerebral distensibility is reduced in parallel with a reduction in cerebrospinal fluid drainage and cognitive deterioration. We propose that aged mice chronically exposed to hypoxia represent an excellent experimental model for studying the pathophysiological characteristics of idiopathic normal pressure hydrocephalus and roles for AQPs in such disease.
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11
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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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12
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Bancroft EA, Srinivasan R. Emerging Roles for Aberrant Astrocytic Calcium Signals in Parkinson's Disease. Front Physiol 2022; 12:812212. [PMID: 35087422 PMCID: PMC8787054 DOI: 10.3389/fphys.2021.812212] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2021] [Accepted: 12/09/2021] [Indexed: 11/25/2022] Open
Abstract
Astrocytes display a plethora of spontaneous Ca2+ signals that modulate vital functions of the central nervous system (CNS). This suggests that astrocytic Ca2+ signals also contribute to pathological processes in the CNS. In this context, the molecular mechanisms by which aberrant astrocytic Ca2+ signals trigger dopaminergic neuron loss during Parkinson's disease (PD) are only beginning to emerge. Here, we provide an evidence-based perspective on potential mechanisms by which aberrant astrocytic Ca2+ signals can trigger dysfunction in three distinct compartments of the brain, viz., neurons, microglia, and the blood brain barrier, thereby leading to PD. We envision that the coming decades will unravel novel mechanisms by which aberrant astrocytic Ca2+ signals contribute to PD and other neurodegenerative processes in the CNS.
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Affiliation(s)
- Eric A. Bancroft
- Department of Neuroscience and Experimental Therapeutics, Texas A&M University College of Medicine, Bryan, TX, United States
| | - Rahul Srinivasan
- Department of Neuroscience and Experimental Therapeutics, Texas A&M University College of Medicine, Bryan, TX, United States
- Texas A&M Institute for Neuroscience (TAMIN), College Station, TX, United States
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13
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Saha S, Mukherjee S, Guha G, Mukhopadhyay D. Dynamics of AQP4 upon exposure to seropositive patient serum before and after Rituximab therapy in Neuromyelitis Optica: A cell-based study. J Neuroimmunol 2021; 361:577752. [PMID: 34715591 DOI: 10.1016/j.jneuroim.2021.577752] [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: 04/28/2021] [Revised: 09/27/2021] [Accepted: 10/12/2021] [Indexed: 10/20/2022]
Abstract
Neuromyelitis Optica (NMO) is an autoimmune inflammatory disease that affects the optic nerves and spinal cord. The autoantibody is generated against the abundant water channel protein of the brain, Aquaporin 4 (AQP4). Of the two isoforms of AQP4, the shorter one (M23) often exists as a supramolecular assembly known as an orthogonal array of particles (OAPs). There have been debates about the fate of these AQP4 clusters upon binding to the antibody, the exact mechanism of its turnover, and the proteins associated with the process. Recently several clinical cases of NMO were reported delineating the effect of Rituximab (RTX) therapy. Extending these reports at the cell signaling level, we developed a glioma based cellular model that mimicked antibody binding and helped us track the subsequent events including a variation of AQP4 levels, alterations in cellular morphology, and the changes in downstream signaling cascades. Our results revealed the extent of perturbations in the signaling pathways related to stress involving ERK, JNK, and AKT1 together with markers for cell death. We could also decipher the possible routes of degradation of AQP4, post-exposure to antibody. We further investigated the effect of autoantibody on AQP4 transcriptional level and involvement of FOXO3a and miRNA-145 in the regulation of transcription. This study highlights the differential outcome at the cellular level when treated with the serum of the same patient pre and post RTX therapy and for the first time mechanistically describes the effect of RTX.
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Affiliation(s)
- Suparna Saha
- Biophysics and Structural Genomics Division, Saha Institute of Nuclear Physics, HBNI.Sector - 1, Block - AF Bidhannagar, Kolkata 700064, India.
| | - Soumava Mukherjee
- Department of Neurology, Nil Ratan Sircar Medical College and Hospital, West Bengal University of Health Sciences, Kolkata, West Bengal, India
| | - Gautam Guha
- Department of Neurology, Nil Ratan Sircar Medical College and Hospital, West Bengal University of Health Sciences, Kolkata, West Bengal, India
| | - Debashis Mukhopadhyay
- Biophysics and Structural Genomics Division, Saha Institute of Nuclear Physics, HBNI.Sector - 1, Block - AF Bidhannagar, Kolkata 700064, India.
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14
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Trillo-Contreras JL, Toledo-Aral JJ, Villadiego J, Echevarría M. Aquaporin-4 Mediates Permanent Brain Alterations in a Mouse Model of Hypoxia-Aged Hydrocephalus. Int J Mol Sci 2021; 22:ijms22189745. [PMID: 34575909 PMCID: PMC8471142 DOI: 10.3390/ijms22189745] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Revised: 09/06/2021] [Accepted: 09/07/2021] [Indexed: 11/29/2022] Open
Abstract
Aquaporin-4 (AQP4) is the principal water channel in the brain being expressed in astrocytes and ependymal cells. AQP4 plays an important role in cerebrospinal fluid (CSF) homeostasis, and alterations in its expression have been associated with hydrocephalus. AQP4 contributes to the development of hydrocephalus by hypoxia in aged mice, reproducing such principal characteristics of the disease. Here, we explore whether these alterations associated with the hydrocephalic state are permanent or can be reverted by reexposure to normoxia. Alterations such as ventriculomegaly, elevated intracranial pressure, and cognitive deficits were reversed, whereas deficits in CSF outflow and ventricular distensibility were not recovered, remaining impaired even one month after reestablishment of normoxia. Interestingly, in AQP4−/− mice, the impairment in CSF drainage and ventricular distensibility was completely reverted by re-normoxia, indicating that AQP4 has a structural role in the chronification of those alterations. Finally, we show that aged mice subjected to two hypoxic episodes experience permanent ventriculomegaly. These data reveal that repetitive hypoxic events in aged cerebral tissue promote the permanent alterations involved in hydrocephalic pathophysiology, which are dependent on AQP4 expression.
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Affiliation(s)
- José Luis Trillo-Contreras
- Institute of Biomedicine of Seville-IBiS, University Hospital Virgen del Rocío, CSIC, University of Seville, 41013 Seville, Spain; (J.L.T.-C.); (J.J.T.-A.)
- Department of Medical Physiology and Biophysics, University of Seville, 41009 Seville, Spain
| | - Juan José Toledo-Aral
- Institute of Biomedicine of Seville-IBiS, University Hospital Virgen del Rocío, CSIC, University of Seville, 41013 Seville, Spain; (J.L.T.-C.); (J.J.T.-A.)
- Department of Medical Physiology and Biophysics, University of Seville, 41009 Seville, Spain
- Network Center for Biomedical Research in Neurodegenerative Diseases (CIBERNED), 28031 Madrid, Spain
| | - Javier Villadiego
- Institute of Biomedicine of Seville-IBiS, University Hospital Virgen del Rocío, CSIC, University of Seville, 41013 Seville, Spain; (J.L.T.-C.); (J.J.T.-A.)
- Department of Medical Physiology and Biophysics, University of Seville, 41009 Seville, Spain
- Network Center for Biomedical Research in Neurodegenerative Diseases (CIBERNED), 28031 Madrid, Spain
- Correspondence: (J.V.); (M.E.); Tel.: +34-955-920-034 (J.V.); +34-955-920-036 (M.E.)
| | - Miriam Echevarría
- Institute of Biomedicine of Seville-IBiS, University Hospital Virgen del Rocío, CSIC, University of Seville, 41013 Seville, Spain; (J.L.T.-C.); (J.J.T.-A.)
- Department of Medical Physiology and Biophysics, University of Seville, 41009 Seville, Spain
- Correspondence: (J.V.); (M.E.); Tel.: +34-955-920-034 (J.V.); +34-955-920-036 (M.E.)
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15
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Ludwig HC, Bock HC, Gärtner J, Schiller S, Frahm J, Dreha-Kulaczewski S. Hydrocephalus Revisited: New Insights into Dynamics of Neurofluids on Macro- and Microscales. Neuropediatrics 2021; 52:233-241. [PMID: 34192788 DOI: 10.1055/s-0041-1731981] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
New experimental and clinical findings question the historic view of hydrocephalus and its 100-year-old classification. In particular, real-time magnetic resonance imaging (MRI) evaluation of cerebrospinal fluid (CSF) flow and detailed insights into brain water regulation on the molecular scale indicate the existence of at least three main mechanisms that determine the dynamics of neurofluids: (1) inspiration is a major driving force; (2) adequate filling of brain ventricles by balanced CSF upsurge is sensed by cilia; and (3) the perivascular glial network connects the ependymal surface to the pericapillary Virchow-Robin spaces. Hitherto, these aspects have not been considered a common physiologic framework, improving knowledge and therapy for severe disorders of normal-pressure and posthemorrhagic hydrocephalus, spontaneous intracranial hypotension, and spaceflight disease.
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Affiliation(s)
- Hans C Ludwig
- Division of Pediatric Neurosurgery, Department of Neurosurgery, University Medical Center Göttingen, Göttingen, Germany
| | - Hans C Bock
- Division of Pediatric Neurosurgery, Department of Neurosurgery, University Medical Center Göttingen, Göttingen, Germany
| | - Jutta Gärtner
- Division of Pediatric Neurology, Department of Pediatrics and Adolescent Medicine, University Medical Center Göttingen, Göttingen, Germany
| | - Stina Schiller
- Division of Pediatric Neurology, Department of Pediatrics and Adolescent Medicine, University Medical Center Göttingen, Göttingen, Germany
| | - Jens Frahm
- Biomedical NMR, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Steffi Dreha-Kulaczewski
- Division of Pediatric Neurology, Department of Pediatrics and Adolescent Medicine, University Medical Center Göttingen, Göttingen, Germany
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16
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Lysosomal Functions in Glia Associated with Neurodegeneration. Biomolecules 2021; 11:biom11030400. [PMID: 33803137 PMCID: PMC7999372 DOI: 10.3390/biom11030400] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2021] [Revised: 03/03/2021] [Accepted: 03/08/2021] [Indexed: 12/12/2022] Open
Abstract
Lysosomes are cellular organelles that contain various acidic digestive enzymes. Despite their small size, they have multiple functions. Lysosomes remove or recycle unnecessary cell parts. They repair damaged cellular membranes by exocytosis. Lysosomes also sense cellular energy status and transmit signals to the nucleus. Glial cells are non-neuronal cells in the nervous system and have an active role in homeostatic support for neurons. In response to dynamic cues, glia use lysosomal pathways for the secretion and uptake of regulatory molecules, which affect the physiology of neighboring neurons. Therefore, functional aberration of glial lysosomes can trigger neuronal degeneration. Here, we review lysosomal functions in oligodendrocytes, astrocytes, and microglia, with emphasis on neurodegeneration.
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17
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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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18
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Álvarez P, Blasco E, Pumarola M, Wessmann A. Aquaporin-4 protein expression in normal canine brains. BMC Vet Res 2021; 17:29. [PMID: 33455577 PMCID: PMC7812730 DOI: 10.1186/s12917-021-02745-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Accepted: 01/01/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Aquaporin-4 (AQP4) is in growing recognition as potential marker for cancer progression, differentiation and therapeutic intervention. No information is available about AQP4 expression in the normal canine brain. The aim of this histopathological study is to confirm the presence of AQP4 by immunohistochemistry technique in a group of non-pathological canine brains and to describe its expression and distribution across the brain. RESULTS Twelve non-pathological canine brains of various ages (ranging from 21 days to 17 years) and breeds were included in the study. Immunohistochemical expression of AQP4 was analyzed using formalin-fixed paraffin-embedded brain tissue sections. The findings were correlated between AQP4 expressing cells and astrocytes using glial fibrillary acidic protein (GFAP). AQP4 expression was more marked in the astrocyte foot processes of subpial, perivascular and periventricular surfaces in all specimens. The majority of the canine brain sections (9/12) presented with an AQP4 predilection for white matter tracts. Interestingly, the two youngest dogs (21 days and 3 months old) were characterized by diffuse AQP4 labelling in both grey and white matter tracts. This result may suggest that brain development and ageing may play a role in the AQP4 distribution throughout the canine brain. CONCLUSIONS This is the first study to describe immunohistochemical distribution of AQP4 in normal canine brains. The AQP4 expression and distribution in non-pathological canine brains was comparable to other species. Larger studies are needed to substantiate the influence of breed and ageing on AQP4 expression in the normal canine brain.
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Affiliation(s)
- Patricia Álvarez
- Neurology and Neurosurgery Service, Pride Veterinary Centre, Derby, UK
| | - Ester Blasco
- Unit of Murine and Comparative Pathology (UPMiC), Department of Animal Medicine and Surgery, Veterinary Faculty, Autonomous University of Barcelona, Barcelona, Spain
| | - Martí Pumarola
- Unit of Murine and Comparative Pathology (UPMiC), Department of Animal Medicine and Surgery, Veterinary Faculty, Autonomous University of Barcelona, Barcelona, Spain.,Center on Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN) Networking Research, Universitat Autònoma de Barcelona, Bellaterra, Barcelona, Spain
| | - Annette Wessmann
- Neurology and Neurosurgery Service, Pride Veterinary Centre, Derby, UK.
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19
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Jorgačevski J, Zorec R, Potokar M. Insights into Cell Surface Expression, Supramolecular Organization, and Functions of Aquaporin 4 Isoforms in Astrocytes. Cells 2020; 9:cells9122622. [PMID: 33297299 PMCID: PMC7762321 DOI: 10.3390/cells9122622] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2020] [Revised: 12/03/2020] [Accepted: 12/05/2020] [Indexed: 12/13/2022] Open
Abstract
Aquaporin 4 (AQP4) is the most abundant water channel in the central nervous system (CNS). Its expression is confined to non-neuronal glial cells, predominantly to astrocytes that represent a heterogeneous glial cell type in the CNS. The membrane of astrocyte processes, which align brain capillaries and pia, is particularly rich in AQP4. Several isoforms of AQP4 have been described; however, only some (AQP4a (M1), AQP4 c (M23), AQP4e, and AQP4ex) have been identified in the plasma membrane assemblies of astrocytes termed orthogonal arrays of particles (OAPs). Intracellular splicing isoforms (AQP4b, AQP4d, AQP4f, AQP4-Δ4) have been documented, and most of them are postulated to have a role in the cell surface distribution of the plasma membrane isoforms and in the formation of OAPs in murine and human astrocytes. Although OAPs have been proposed to play various roles in the functioning of astrocytes and CNS tissue as a whole, many of these still need to be described. OAPs are studied primarily from the perspective of understanding water permeability regulation through the plasma membrane and of their involvement in cell adhesion and in the dynamics of astrocytic processes. This review describes the cellular distribution of various AQP4 isoforms and their implications in OAP assembly, which is regulated by several intracellular and extracellular proteins.
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Affiliation(s)
- Jernej Jorgačevski
- Laboratory of Neuroendocrinology—Molecular Cell Physiology, Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Zaloška 4, 1000 Ljubljana, Slovenia; (J.J.); (R.Z.)
- Celica Biomedical, Tehnološki park 24, 1000 Ljubljana, Slovenia
| | - Robert Zorec
- Laboratory of Neuroendocrinology—Molecular Cell Physiology, Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Zaloška 4, 1000 Ljubljana, Slovenia; (J.J.); (R.Z.)
- Celica Biomedical, Tehnološki park 24, 1000 Ljubljana, Slovenia
| | - Maja Potokar
- Laboratory of Neuroendocrinology—Molecular Cell Physiology, Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Zaloška 4, 1000 Ljubljana, Slovenia; (J.J.); (R.Z.)
- Celica Biomedical, Tehnološki park 24, 1000 Ljubljana, Slovenia
- Correspondence: ; Tel.: +386-1543-7020; Fax: +386-1543-7036
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20
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Howe MD, McCullough LD, Urayama A. The Role of Basement Membranes in Cerebral Amyloid Angiopathy. Front Physiol 2020; 11:601320. [PMID: 33329053 PMCID: PMC7732667 DOI: 10.3389/fphys.2020.601320] [Citation(s) in RCA: 14] [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: 08/31/2020] [Accepted: 10/28/2020] [Indexed: 12/25/2022] Open
Abstract
Dementia is a neuropsychiatric syndrome characterized by cognitive decline in multiple domains, often leading to functional impairment in activities of daily living, disability, and death. The most common causes of age-related progressive dementia include Alzheimer's disease (AD) and vascular cognitive impairment (VCI), however, mixed disease pathologies commonly occur, as epitomized by a type of small vessel pathology called cerebral amyloid angiopathy (CAA). In CAA patients, the small vessels of the brain become hardened and vulnerable to rupture, leading to impaired neurovascular coupling, multiple microhemorrhage, microinfarction, neurological emergencies, and cognitive decline across multiple functional domains. While the pathogenesis of CAA is not well understood, it has long been thought to be initiated in thickened basement membrane (BM) segments, which contain abnormal protein deposits and amyloid-β (Aβ). Recent advances in our understanding of CAA pathogenesis link BM remodeling to functional impairment of perivascular transport pathways that are key to removing Aβ from the brain. Dysregulation of this process may drive CAA pathogenesis and provides an important link between vascular risk factors and disease phenotype. The present review summarizes how the structure and composition of the BM allows for perivascular transport pathways to operate in the healthy brain, and then outlines multiple mechanisms by which specific dementia risk factors may promote dysfunction of perivascular transport pathways and increase Aβ deposition during CAA pathogenesis. A better understanding of how BM remodeling alters perivascular transport could lead to novel diagnostic and therapeutic strategies for CAA patients.
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Affiliation(s)
| | | | - Akihiko Urayama
- Department of Neurology, McGovern Medical School, The University of Texas Health Science Center at Houston, Houston, TX, United States
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Cohen-Salmon M, Slaoui L, Mazaré N, Gilbert A, Oudart M, Alvear-Perez R, Elorza-Vidal X, Chever O, Boulay AC. Astrocytes in the regulation of cerebrovascular functions. Glia 2020; 69:817-841. [PMID: 33058289 DOI: 10.1002/glia.23924] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Revised: 09/18/2020] [Accepted: 09/21/2020] [Indexed: 12/18/2022]
Abstract
Astrocytes are the most numerous type of neuroglia in the brain and have a predominant influence on the cerebrovascular system; they control perivascular homeostasis, the integrity of the blood-brain barrier, the dialogue with the peripheral immune system, the transfer of metabolites from the blood, and blood vessel contractility in response to neuronal activity. These regulatory processes occur in a specialized interface composed of perivascular astrocyte extensions that almost completely cover the cerebral blood vessels. Scientists have only recently started to study how this interface is formed and how it influences cerebrovascular functions. Here, we review the literature on the astrocytes' role in the regulation of the cerebrovascular system. We cover the anatomy and development of the gliovascular interface, the known gliovascular functions, and molecular factors, the latter's implication in certain pathophysiological situations, and recent cutting-edge experimental tools developed to examine the astrocytes' role at the vascular interface. Finally, we highlight some open questions in this field of research.
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Affiliation(s)
- Martine Cohen-Salmon
- Physiology and Physiopathology of the Gliovascular Unit Research Group, Center for Interdisciplinary Research in Biology (CIRB), College de France, CNRS Unité Mixte de Recherche 724, INSERM Unité 1050, Labex Memolife, PSL Research University, Paris, France
| | - Leila Slaoui
- Physiology and Physiopathology of the Gliovascular Unit Research Group, Center for Interdisciplinary Research in Biology (CIRB), College de France, CNRS Unité Mixte de Recherche 724, INSERM Unité 1050, Labex Memolife, PSL Research University, Paris, France
| | - Noémie Mazaré
- Physiology and Physiopathology of the Gliovascular Unit Research Group, Center for Interdisciplinary Research in Biology (CIRB), College de France, CNRS Unité Mixte de Recherche 724, INSERM Unité 1050, Labex Memolife, PSL Research University, Paris, France
| | - Alice Gilbert
- Physiology and Physiopathology of the Gliovascular Unit Research Group, Center for Interdisciplinary Research in Biology (CIRB), College de France, CNRS Unité Mixte de Recherche 724, INSERM Unité 1050, Labex Memolife, PSL Research University, Paris, France
| | - Marc Oudart
- Physiology and Physiopathology of the Gliovascular Unit Research Group, Center for Interdisciplinary Research in Biology (CIRB), College de France, CNRS Unité Mixte de Recherche 724, INSERM Unité 1050, Labex Memolife, PSL Research University, Paris, France
| | - Rodrigo Alvear-Perez
- Physiology and Physiopathology of the Gliovascular Unit Research Group, Center for Interdisciplinary Research in Biology (CIRB), College de France, CNRS Unité Mixte de Recherche 724, INSERM Unité 1050, Labex Memolife, PSL Research University, Paris, France
| | - Xabier Elorza-Vidal
- Physiology and Physiopathology of the Gliovascular Unit Research Group, Center for Interdisciplinary Research in Biology (CIRB), College de France, CNRS Unité Mixte de Recherche 724, INSERM Unité 1050, Labex Memolife, PSL Research University, Paris, France
| | - Oana Chever
- Normandie University, UNIROUEN, INSERM, DC2N, IRIB, Rouen, France
| | - Anne-Cécile Boulay
- Physiology and Physiopathology of the Gliovascular Unit Research Group, Center for Interdisciplinary Research in Biology (CIRB), College de France, CNRS Unité Mixte de Recherche 724, INSERM Unité 1050, Labex Memolife, PSL Research University, Paris, France
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22
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Noël G, Tham DKL, Guadagno E, MacVicar B, Moukhles H. The Laminin-Induced Phosphorylation of PKCδ Regulates AQP4 Distribution and Water Permeability in Rat Astrocytes. Cell Mol Neurobiol 2020; 41:1743-1757. [PMID: 32851539 DOI: 10.1007/s10571-020-00944-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2020] [Accepted: 08/14/2020] [Indexed: 11/29/2022]
Abstract
In astrocytes, the water-permeable channel aquaporin-4 (AQP4) is concentrated at the endfeet that abut the blood vessels of the brain. The asymmetric distribution of this channel is dependent on the function of dystroglycan (DG), a co-expressed laminin receptor, and its associated protein complex. We have demonstrated that the addition of laminin to astrocytes in culture causes the clustering of AQP4, DG, and lipid rafts. The last, in particular, have been associated with the initiation of cell signaling. As laminin binding to DG in muscle cells can induce the tyrosine phosphorylation of syntrophin and laminin requires tyrosine kinases for acetylcholine receptor clustering in myotubes, we asked if signal transduction might also be involved in AQP4 clustering in astrocytes. We analyzed the timecourse of AQP4, DG, and monosialotetrahexosylganglioside (GM1) clustering in primary cultures of rat astrocytes following the addition of laminin, and determined that the clustering of DG precedes that of AQP4 and GM1. We also showed that laminin induces the formation of phosphotyrosine-rich clusters and that the tyrosine kinase inhibitor, genistein, disrupts the laminin-induced clustering of both β-DG and AQP4. Using the Kinexus antibody microarray chip, we then identified protein-serine kinase C delta (PKCδ) as one of the main proteins exhibiting high levels of tyrosine phosphorylation upon laminin treatment. Selective inhibitors of PKC and siRNA against PKCδ disrupted β-DG and AQP4 clustering, and also caused water transport to increase in astrocytes treated with laminin. Our results demonstrate that the effects of laminin on AQP4 localization and function are relayed, at least in part, through PKC signaling.
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Affiliation(s)
- Geoffroy Noël
- Department of Cellular and Physiological Sciences, Life Sciences Institute, University of British Columbia, 2350 Health Sciences Mall, Vancouver, V6T 1Z3, Canada
| | - Daniel Kai Long Tham
- Department of Cellular and Physiological Sciences, Life Sciences Institute, University of British Columbia, 2350 Health Sciences Mall, Vancouver, V6T 1Z3, Canada
| | - Eric Guadagno
- Department of Cellular and Physiological Sciences, Life Sciences Institute, University of British Columbia, 2350 Health Sciences Mall, Vancouver, V6T 1Z3, Canada
| | - Brian MacVicar
- Department of Psychiatry, Djavad Mowafaghian Centre for Brain Health, University of British Columbia, 2215 Wesbrook Mall, Vancouver, V6T 1Z3, Canada
| | - Hakima Moukhles
- Department of Cellular and Physiological Sciences, Life Sciences Institute, University of British Columbia, 2350 Health Sciences Mall, Vancouver, V6T 1Z3, Canada.
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23
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Gao M, Lu W, Shu Y, Yang Z, Sun S, Xu J, Gan S, Zhu S, Qiu G, Zhuo F, Xu S, Wang Y, Chen J, Wu X, Huang J. Poldip2 mediates blood-brain barrier disruption and cerebral edema by inducing AQP4 polarity loss in mouse bacterial meningitis model. CNS Neurosci Ther 2020; 26:1288-1302. [PMID: 32790044 PMCID: PMC7702237 DOI: 10.1111/cns.13446] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2020] [Revised: 06/27/2020] [Accepted: 07/05/2020] [Indexed: 12/20/2022] Open
Abstract
Background Specific highly polarized aquaporin‐4 (AQP4) expression is reported to play a crucial role in blood‐brain barrier (BBB) integrity and brain water transport balance. The upregulation of polymerase δ‐interacting protein 2 (Poldip2) was involved in aggravating BBB disruption following ischemic stroke. This study aimed to investigate whether Poldip2‐mediated BBB disruption and cerebral edema formation in mouse bacterial meningitis (BM) model occur via induction of AQP4 polarity loss. Methods and Results Mouse BM model was induced by injecting mice with group B hemolytic streptococci via posterior cistern. Recombinant human Poldip2 (rh‐Poldip2) was administered intranasally at 1 hour after BM induction. Small interfering ribonucleic acid (siRNA) targeting Poldip2 was administered by intracerebroventricular (i.c.v) injection at 48 hours before BM induction. A specific inhibitor of matrix metalloproteinases (MMPs), UK383367, was administered intravenously at 0.5 hour before BM induction. Western blotting, immunofluorescence staining, quantitative real‐time PCR, neurobehavioral test, brain water content test, Evans blue (EB) permeability assay, transmission electron microscopy (TEM), and gelatin zymography were carried out. The results showed that Poldip2 was upregulated and AQP4 polarity was lost in mouse BM model. Both Poldip2 siRNA and UK383367 improved neurobehavioral outcomes, alleviated brain edema, preserved the integrity of BBB, and relieved the loss of AQP4 polarity in BM model. Rh‐Poldip2 upregulated the expression of MMPs and glial fibrillary acidic protein (GFAP) and downregulated the expression of β‐dystroglycan (β‐DG), zonula occludens‐1 (ZO‐1), occludin, and claudin‐5; whereas Poldip2 siRNA downregulated the expression of MMPs and GFAP, and upregulated β‐DG, ZO‐1, occludin, and claudin‐5. Similarly, UK383367 downregulated the expression of GFAP and upregulated the expression of β‐DG, ZO‐1, occludin, and claudin‐5. Conclusion Poldip2 inhibition alleviated brain edema and preserved the integrity of BBB partially by relieving the loss of AQP4 polarity via MMPs/β‐DG pathway.
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Affiliation(s)
- Meng Gao
- Department of Anatomy, Chongqing Medical University, Chongqing, China
| | - Weitian Lu
- Department of Anatomy, Chongqing Medical University, Chongqing, China.,Institute of Neuroscience, Chongqing Medical University, Chongqing, China
| | - Yue Shu
- Department of Anatomy, Chongqing Medical University, Chongqing, China
| | - Zhengyu Yang
- Department of Anatomy, Chongqing Medical University, Chongqing, China
| | - Shanquan Sun
- Department of Anatomy, Chongqing Medical University, Chongqing, China.,Institute of Neuroscience, Chongqing Medical University, Chongqing, China
| | - Jin Xu
- Department of Anatomy, Chongqing Medical University, Chongqing, China.,Institute of Neuroscience, Chongqing Medical University, Chongqing, China
| | - Shengwei Gan
- Department of Anatomy, Chongqing Medical University, Chongqing, China.,Institute of Neuroscience, Chongqing Medical University, Chongqing, China
| | - Shujuan Zhu
- Department of Anatomy, Chongqing Medical University, Chongqing, China.,Institute of Neuroscience, Chongqing Medical University, Chongqing, China
| | - Guoping Qiu
- Department of Anatomy, Chongqing Medical University, Chongqing, China.,Institute of Neuroscience, Chongqing Medical University, Chongqing, China
| | - Fei Zhuo
- Department of Anatomy, Chongqing Medical University, Chongqing, China.,Institute of Neuroscience, Chongqing Medical University, Chongqing, China
| | - Shiye Xu
- Department of Anatomy, Chongqing Medical University, Chongqing, China.,Institute of Neuroscience, Chongqing Medical University, Chongqing, China
| | - Yiying Wang
- Department of Anatomy, Chongqing Medical University, Chongqing, China
| | - Junhong Chen
- Department of Anatomy, Chongqing Medical University, Chongqing, China
| | - Xuan Wu
- Department of Neurosurgery, The Second Affiliated Hospital, Chongqing Medical University, Chongqing, China
| | - Juan Huang
- Department of Anatomy, Chongqing Medical University, Chongqing, China.,Institute of Neuroscience, Chongqing Medical University, Chongqing, China
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24
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Filchenko I, Blochet C, Buscemi L, Price M, Badaut J, Hirt L. Caveolin-1 Regulates Perivascular Aquaporin-4 Expression After Cerebral Ischemia. Front Cell Dev Biol 2020; 8:371. [PMID: 32523952 PMCID: PMC7261922 DOI: 10.3389/fcell.2020.00371] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Accepted: 04/27/2020] [Indexed: 01/25/2023] Open
Abstract
Edema is a hallmark of many brain disorders including stroke. During vasogenic edema, blood-brain barrier (BBB) permeability increases, contributing to the entry of plasma proteins followed by water. Caveolae and caveolin-1 (Cav-1) are involved in these BBB permeability changes. The expression of the aquaporin-4 (AQP4) water channel relates to brain swelling, however, its regulation is poorly understood. Here we tested whether Cav-1 regulates AQP4 expression in the perivascular region after brain ischemia in mice. We showed that Cav-1 knockout mice had enhanced hemispheric swelling and decreased perivascular AQP4 expression in perilesional and contralateral cortical regions compared to wild-type. Glial fibrillary acidic protein-positive astrocytes displayed less branching and ramification in Cav-1 knockout mice compared to wild-type animals. There was a positive correlation between the area of perivascular AQP4-immunolabelling and branch length of Glial fibrillary acidic protein-positive astrocytes in wild-type mice, not seen in Cav-1 knockout mice. In summary, we show for the first time that loss of Cav-1 results in decreased AQP4 expression and impaired perivascular AQP4 covering after cerebral ischemia associated with altered reactive astrocyte morphology and enhanced brain swelling. Therapeutic approaches targeting Cav-1 may provide new opportunities for improving stroke outcome.
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Affiliation(s)
- Irina Filchenko
- Service of Neurology, Department of Clinical Neurosciences, CHUV, Lausanne, Switzerland.,North-Western State Medical University named after I.I. Mechnikov, Saint-Petersburg, Russia.,Department of Fundamental Neurosciences, University of Lausanne, Lausanne, Switzerland
| | - Camille Blochet
- Service of Neurology, Department of Clinical Neurosciences, CHUV, Lausanne, Switzerland.,Department of Fundamental Neurosciences, University of Lausanne, Lausanne, Switzerland
| | - Lara Buscemi
- Service of Neurology, Department of Clinical Neurosciences, CHUV, Lausanne, Switzerland.,Department of Fundamental Neurosciences, University of Lausanne, Lausanne, Switzerland
| | - Melanie Price
- Service of Neurology, Department of Clinical Neurosciences, CHUV, Lausanne, Switzerland.,Department of Fundamental Neurosciences, University of Lausanne, Lausanne, Switzerland
| | - Jerome Badaut
- Brain Molecular Imaging Lab, CNRS UMR 5287, INCIA, University of Bordeaux, Bordeaux, France.,Basic Science Department, Loma Linda University School of Medicine, Loma Linda, CA, United States
| | - Lorenz Hirt
- Service of Neurology, Department of Clinical Neurosciences, CHUV, Lausanne, Switzerland.,Department of Fundamental Neurosciences, University of Lausanne, Lausanne, Switzerland
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25
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Lisjak M, Potokar M, Zorec R, Jorgačevski J. Indirect Role of AQP4b and AQP4d Isoforms in Dynamics of Astrocyte Volume and Orthogonal Arrays of Particles. Cells 2020; 9:cells9030735. [PMID: 32192013 PMCID: PMC7140617 DOI: 10.3390/cells9030735] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Revised: 03/10/2020] [Accepted: 03/13/2020] [Indexed: 01/10/2023] Open
Abstract
Water channel aquaporin 4 (AQP4) plays a key role in the regulation of water homeostasis in the central nervous system (CNS). It is predominantly expressed in astrocytes lining blood–brain and blood–liquor boundaries. AQP4a (M1), AQP4c (M23), and AQP4e, present in the plasma membrane, participate in the cell volume regulation of astrocytes. The function of their splicing variants, AQP4b and AQP4d, predicted to be present in the cytoplasm, is unknown. We examined the cellular distribution of AQP4b and AQP4d in primary rat astrocytes and their role in cell volume regulation. The AQP4b and AQP4d isoforms exhibited extensive cytoplasmic localization in early and late endosomes/lysosomes and in the Golgi apparatus. Neither isoform localized to orthogonal arrays of particles (OAPs) in the plasma membrane. The overexpression of AQP4b and AQP4d isoforms in isoosmotic conditions reduced the density of OAPs; in hypoosmotic conditions, they remained absent from OAPs. In hypoosmotic conditions, the AQP4d isoform was significantly redistributed to early endosomes, which correlated with the increased trafficking of AQP4-laden vesicles. The overexpression of AQP4d facilitated the kinetics of cell swelling, without affecting the regulatory volume decrease. Therefore, although they reside in the cytoplasm, AQP4b and AQP4d isoforms may play an indirect role in astrocyte volume changes.
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Affiliation(s)
- Marjeta Lisjak
- Laboratory of Neuroendocrinology–Molecular Cell Physiology, Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Zaloška 4, 1000 Ljubljana, Slovenia; (M.L.); (M.P.); (R.Z.)
| | - Maja Potokar
- Laboratory of Neuroendocrinology–Molecular Cell Physiology, Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Zaloška 4, 1000 Ljubljana, Slovenia; (M.L.); (M.P.); (R.Z.)
- Celica Biomedical, Tehnološki park 24, 1000 Ljubljana, Slovenia
| | - Robert Zorec
- Laboratory of Neuroendocrinology–Molecular Cell Physiology, Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Zaloška 4, 1000 Ljubljana, Slovenia; (M.L.); (M.P.); (R.Z.)
- Celica Biomedical, Tehnološki park 24, 1000 Ljubljana, Slovenia
| | - Jernej Jorgačevski
- Laboratory of Neuroendocrinology–Molecular Cell Physiology, Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Zaloška 4, 1000 Ljubljana, Slovenia; (M.L.); (M.P.); (R.Z.)
- Celica Biomedical, Tehnološki park 24, 1000 Ljubljana, Slovenia
- Correspondence: ; Tel.: +38615437081
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26
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Hoddevik EH, Rao SB, Zahl S, Boldt HB, Ottersen OP, Amiry-Moghaddam M. Organisation of extracellular matrix proteins laminin and agrin in pericapillary basal laminae in mouse brain. Brain Struct Funct 2020; 225:805-816. [PMID: 32072250 PMCID: PMC7046580 DOI: 10.1007/s00429-020-02036-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2019] [Accepted: 01/29/2020] [Indexed: 01/08/2023]
Abstract
Evidence suggests that extracellular matrix molecules of perivascular basal laminae help orchestrate the molecular assemblies at the gliovascular interface. Specifically, laminin and agrin are thought to tether the dystrophin-associated protein (DAP) complex to the astrocytic basal lamina. This complex includes α-syntrophin (α-Syn), which is believed to anchor aquaporin-4 (AQP4) to astrocytic endfoot membrane domains. We have previously shown that the size of the perivascular AQP4 pool differs considerably between brain regions in an α-Syn-dependent manner. Also, both AQP4 and α-Syn occur at higher densities in endfoot membrane domains facing pericytes than in endfoot membrane domains facing endothelial cells. The heterogeneous distribution of AQP4 at the regional and capillary level has been attributed to a direct interaction between AQP4 and α-Syn. This would be challenged (1) if the microdistributions of laminin and agrin fail to align with those of DAP and AQP4 and (2) if targeted deletion of α-Syn leads to a loss of laminin and/or agrin. Here, we provide the first detailed and quantitative analysis of laminin and agrin in brain basal laminae of mice. We show that the microdistributions of these molecules vary in a fashion that is well aligned with the previously reported microdistribution of AQP4. We also demonstrate that the expression patterns of laminin and agrin are insensitive to targeted deletion of α-Syn, suggesting that α-Syn deletion affects AQP4 directly and not indirectly via laminin or agrin. These data fill remaining voids in the current model of how key molecules are assembled and tethered at the gliovascular interface.
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Affiliation(s)
- Eystein Hellstrøm Hoddevik
- Division of Anatomy, Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, Blindern, Post box 1105, 0317, Oslo, Norway
- Department of Pathology, Oslo University Hospital, Oslo, Norway
| | - Shreyas Balachandra Rao
- Division of Anatomy, Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, Blindern, Post box 1105, 0317, Oslo, Norway
| | - Soulmaz Zahl
- Division of Anatomy, Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, Blindern, Post box 1105, 0317, Oslo, Norway
| | - Henning Bünsow Boldt
- Division of Anatomy, Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, Blindern, Post box 1105, 0317, Oslo, Norway
- Department of Pathology, Odense University Hospital, Odense, Denmark
| | - Ole Petter Ottersen
- Division of Anatomy, Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, Blindern, Post box 1105, 0317, Oslo, Norway
- President's Office, Karolinska Institutet, Nobels väg 6, 171 77, Stockholm, Sweden
| | - Mahmood Amiry-Moghaddam
- Division of Anatomy, Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, Blindern, Post box 1105, 0317, Oslo, Norway.
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27
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Li D, Liu X, Liu T, Liu H, Tong L, Jia S, Wang YF. Neurochemical regulation of the expression and function of glial fibrillary acidic protein in astrocytes. Glia 2019; 68:878-897. [PMID: 31626364 DOI: 10.1002/glia.23734] [Citation(s) in RCA: 85] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2019] [Revised: 08/27/2019] [Accepted: 09/17/2019] [Indexed: 12/30/2022]
Abstract
Glial fibrillary acidic protein (GFAP), a type III intermediate filament, is a marker of mature astrocytes. The expression of GFAP gene is regulated by many transcription factors (TFs), mainly Janus kinase-2/signal transducer and activator of transcription 3 cascade and nuclear factor κ-light-chain-enhancer of activated B cell signaling. GFAP expression is also modulated by protein kinase and other signaling molecules that are elicited by neuronal activity and hormones. Abnormal expression of GFAP proteins occurs in neuroinflammation, neurodegeneration, brain edema-eliciting diseases, traumatic brain injury, psychiatric disorders and others. GFAP, mainly in α-isoform, is the major component of cytoskeleton and the scaffold of astrocytes, which is essential for the maintenance of astrocytic structure and shape. GFAP also has highly morphological plasticity because of its quick changes in assembling and polymerizing states in response to environmental challenges. This plasticity and its corresponding cellular morphological changes endow astrocytes the functions of physical barrier between adjacent neurons and stabilizer of extracellular environment. Moreover, GFAP colocalizes and even molecularly associates with many functional molecules. This feature allows GFAP to function as a platform for direct interactions between different molecules. Last, GFAP involves transportation and localization of other functional proteins and thus serves as a protein transport guide in astrocytes. This guiding role of GFAP involves an elastic retraction and extension cytoskeletal network that couples with GFAP reassembling, transporting, and membrane protein recycling machinery. This paper reviews our current understanding of the expression and functions of GFAP as well as their regulation.
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Affiliation(s)
- Dongyang Li
- Department of Physiology, Harbin Medical University, Harbin, China
| | - Xiaoyu Liu
- Department of Physiology, Harbin Medical University, Harbin, China
| | - Tianming Liu
- Department of Physiology, Harbin Medical University, Harbin, China
| | - Haitao Liu
- Department of Physiology, Harbin Medical University, Harbin, China
| | - Li Tong
- Department of Physiology, Harbin Medical University, Harbin, China
| | - Shuwei Jia
- Department of Physiology, Harbin Medical University, Harbin, China
| | - Yu-Feng Wang
- Department of Physiology, Harbin Medical University, Harbin, China
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28
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Noël G, Tham DKL, MacVicar BA, Moukhles H. Agrin plays a major role in the coalescence of the aquaporin-4 clusters induced by gamma-1-containing laminin. J Comp Neurol 2019; 528:407-418. [PMID: 31454080 DOI: 10.1002/cne.24763] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2019] [Revised: 07/13/2019] [Accepted: 08/22/2019] [Indexed: 01/06/2023]
Abstract
The basement membrane that seperates the endothelial cells and astrocytic endfeet that comprise the blood-brain barrier is rich in collagen, laminin, agrin, and perlecan. Previous studies have demonstrated that the proper recruitment of the water-permeable channel aquaporin-4 (AQP4) to astrocytic endfeet is dependent on interactions between laminin and the receptor dystroglycan. In this study, we conducted a deeper investigation into how the basement membrane might further regulate the expression, localization, and function of AQP4, using primary astrocytes as a model system. We found that treating these cells with laminin causes endogenous agrin to localize to the cell surface, where it co-clusters with β-dystroglycan (β-DG). Conversely, agrin sliencing profoundly disrupts β-DG clustering. As in the case of laminin111, Matrigel™, a complete basement membrane analog, also causes the clustering of AQP4 and β-DG. This clustering, whether induced by laminin111 or Matrigel™ is inhibited when the astrocytes are first incubated with an antibody against the γ1 subunit of laminin, suggesting that the latter is crucial to the process. Finally, we showed that laminin111 appears to negatively regulate AQP4-mediated water transport in astrocytes, suppressing the cell swelling that occurs following a hypoosmotic challenge. This suppression is abolished if DG expression is silenced, again demonstrating the central role of this receptor in relaying the effects of laminin.
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Affiliation(s)
- Geoffroy Noël
- Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, British Columbia, Canada
| | - Daniel Kai Long Tham
- Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, British Columbia, Canada
| | - Brian A MacVicar
- Department of Psychiatry, University of British Columbia, Vancouver, British Columbia, Canada
| | - Hakima Moukhles
- Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, British Columbia, Canada
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29
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Zhang X, Gu Y, Li P, Jiang A, Sheng X, Jin X, Shi Y, Li G. Matrix Metalloproteases-Mediated Cleavage on β-Dystroglycan May Play a Key Role in the Blood-Brain Barrier After Intracerebral Hemorrhage in Rats. Med Sci Monit 2019; 25:794-800. [PMID: 30686819 PMCID: PMC6362757 DOI: 10.12659/msm.908500] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND It is well documented that the Blood-Brain barrier (BBB) can be damaged by matrix metalloproteases (MMPs) after intracerebral hemorrhage (ICH), but little is known about the mechanism of this effect. MATERIAL AND METHODS We established an ICH model in rats by injecting collagenase VII into the striatum. Afterwards, intraperitoneal injection of these rats with 40 mg/kg GM6001 (a MMPs inhibitor). The effects of GM6001 on ICH were investigated by neurological severity score, brain water content, Evans blue staining, hematoxylin-eosin staining, immunohistochemical staining, and Western blot assays. RESULTS We demonstrated that the neurological damage caused by ICH was relieved at 5 and 7 days following administration of GM6001. The impaired BBB induced by ICH was improved in response to GM6001 treatment at around 3 days, as evidenced by alleviated cerebral edema, decreased Evans blue extravasation, and a reduction in inflammatory cellular infiltration. Mechanism analysis revealed that ICH induced the generation of β-dystroglycan cleavage, which could be suppressed by GM6001 treatment. Furthermore, we found that recombinant MMP2 and MMP9 triggered the cleavage of β-dystroglycan in vitro, and this action could be inhibited by GM6001 administration. CONCLUSIONS Taken together, our results suggest that MMPs-mediated cleavage on β-dystroglycan may play an important role in BBB after ICH.
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Affiliation(s)
- Xin Zhang
- Department of Neurology, The First Affiliated Hospital of Harbin Medical University, Harbin, Heilongjiang, China (mainland)
| | - Yunhe Gu
- Department of Pathology, The First Affiliated Hospital of Harbin Medical University, Harbin, Heilongjiang, China (mainland)
| | - Peitong Li
- Department of Neurology, The First Affiliated Hospital of Harbin Medical University, Harbin, Heilongjiang, China (mainland)
| | - Anqi Jiang
- Department of Neurology, The First Affiliated Hospital of Harbin Medical University, Harbin, Heilongjiang, China (mainland)
| | - Xiaomeng Sheng
- Department of Neurology, Harbin Fourth Hospital, Harbin, Heilongjiang, China (mainland)
| | - Xin Jin
- Department of Neurology, Jixi People's Hospital, Jixi, Heilongjiang, China (mainland)
| | - Yue Shi
- Department of Neurology, The First Affiliated Hospital of Harbin Medical University, Harbin, Heilongjiang, China (mainland)
| | - Guozhong Li
- Department of Neurology, The First Affiliated Hospital of Harbin Medical University, Harbin, Heilongjiang, China (mainland)
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30
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Pericytes in Primary Familial Brain Calcification. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1147:247-264. [PMID: 31147881 DOI: 10.1007/978-3-030-16908-4_11] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Pericytes are perivascular cells along capillaries that are critical for the development of a functional vascular bed in the central nervous system and other organs. Pericyte functions in the adult brain are less well understood. Pericytes have been suggested to mediate functional hyperemia at the capillary level, regulate the blood-brain barrier and to give rise to scar tissue after spinal cord injury. Furthermore, pericyte loss has been suggested to precede cognitive decline in mouse models of Alzheimer's disease. Despite this observation, there is no convincing causality between pericyte loss and the pathogenesis of Alzheimer's disease. However, recent loss-of-function mutations in PDGFB and PDGFRB genes have implicated pericytes as the principle cell type affected in primary familiar brain calcification (PFBC), a neuropsychiatric disorder with dominant inheritance. Here we review the role of the PDGFB/PDGFRB signaling pathway in pericyte development and briefly discuss homeostatic functions of pericytes in the brain. We provide an overview of recent studies with mouse models of PFBC and discuss suggested pathogenic mechanisms for PFBC with special reference to pericytes.
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31
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Bi C, Tham DKL, Perronnet C, Joshi B, Nabi IR, Moukhles H. The Oxidative Stress-Induced Increase in the Membrane Expression of the Water-Permeable Channel Aquaporin-4 in Astrocytes Is Regulated by Caveolin-1 Phosphorylation. Front Cell Neurosci 2017; 11:412. [PMID: 29326556 PMCID: PMC5742350 DOI: 10.3389/fncel.2017.00412] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2017] [Accepted: 12/08/2017] [Indexed: 01/14/2023] Open
Abstract
The reperfusion of ischemic brain tissue following a cerebral stroke causes oxidative stress, and leads to the generation of reactive oxygen species (ROS). Apart from inflicting oxidative damage, the latter may also trigger the upregulation of aquaporin 4 (AQP4), a water-permeable channel expressed by astroglial cells of the blood-brain barrier (BBB), and contribute to edema formation, the severity of which is known to be the primary determinant of mortality and morbidity. The mechanism through which this occurs remains unknown. In the present study, we have attempted to address this question using primary astrocyte cultures treated with hydrogen peroxide (H2O2) as a model system. First, we showed that H2O2 induces a significant increase in AQP4 protein levels and that this is inhibited by the antioxidant N-acetylcysteine (NAC). Second, we demonstrated using cell surface biotinylation that H2O2 increases AQP4 cell-surface expression independently of it's increased synthesis. In parallel, we found that caveolin-1 (Cav1) is phosphorylated in response to H2O2 and that this is reversed by the Src kinase inhibitor 4-Amino-5-(4-chlorophenyl)-7-(t-butyl)pyrazolo[3,4-d]pyrimidine (PP2). PP2 also abrogated the H2O2-induced increase in AQP4 surface levels, suggesting that the phosphorylation of tyrosine-14 of Cav1 regulates this process. We further showed that dominant-negative Y14F and phosphomimetic Y14D mutants caused a decrease and increase in AQP4 membrane expression respectively, and that the knockdown of Cav1 inhibits the increase in AQP4 cell-surface, expression following H2O2 treatment. Together, these findings suggest that oxidative stress-induced Cav1 phosphorylation modulates AQP4 subcellular distribution and therefore may indirectly regulate AQP4-mediated water transport.
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Affiliation(s)
- Chongshan Bi
- Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, BC, Canada
| | - Daniel K L Tham
- Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, BC, Canada
| | - Caroline Perronnet
- Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, BC, Canada
| | - Bharat Joshi
- Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, BC, Canada
| | - Ivan R Nabi
- Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, BC, Canada
| | - Hakima Moukhles
- Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, BC, Canada
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Fang Y, Dong Y, Zheng T, Du D, Wen J, Gao D, Liu L. Altered Tracer Distribution and Clearance in the Extracellular Space of the Substantia Nigra in a Rodent Model of Parkinson's Disease. Front Neurosci 2017; 11:409. [PMID: 28790882 PMCID: PMC5524830 DOI: 10.3389/fnins.2017.00409] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2017] [Accepted: 06/30/2017] [Indexed: 01/12/2023] Open
Abstract
The relationship between extracellular space (ECS) diffusion parameters and brain drug clearance is not well-studied, especially in the context of Parkinson's disease (PD). Therefore, we used a rodent model of PD to explore the distribution and clearance of a magnetic resonance tracer. Forty male Sprague Dawley rats were randomized into four different groups: a PD group, a Madopar group (PD + Madopar treatment), a sham group, and a control group. All rats received an injection of the extracellular tracer gadolinium-diethylene triaminepentacetic acid (Gd-DTPA) directly into the substantia nigra (SN). ECS diffusion parameters including the effective diffusion coefficient (D*), clearance coefficient (k'), ratio of the maximum distribution volume of the tracer (Vd-max%), and half-life (t1/2) were measured. We found that all parameters were significantly increased in the PD group compared to the other three groups (D*: F = 5.774, p = 0.0025; k': F = 20.00, P < 0.0001; Vd-max%: F = 12.81, P < 0.0001; and t1/2: F = 23.35, P < 0.0001). In conclusion, the PD group exhibited a wider distribution and lower clearance of the tracer compared to the other groups. Moreover, k' was more sensitive than D* for monitoring morphological and functional changes in the ECS in a rodent model of PD.
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Affiliation(s)
- Yuan Fang
- Department of Magnetic Resonance Imaging, Qinhuangdao Municipal No. 1 HospitalQinhuangdao, China
| | - Yanchao Dong
- Department of Interventional Therapy, Qinhuangdao Municipal No. 1 HospitalQinhuangdao, China
| | - Tao Zheng
- Department of Magnetic Resonance Imaging, Qinhuangdao Municipal No. 1 HospitalQinhuangdao, China
| | - Dan Du
- Department of Magnetic Resonance Imaging, Qinhuangdao Municipal No. 1 HospitalQinhuangdao, China
| | - Jiexia Wen
- Department of Central Laboratory, Qinhuangdao Municipal No. 1 HospitalQinhuangdao, China
| | - Dawei Gao
- Institute of Chemical and Environmental Engineering, Yanshan UniversityQinhuangdao, China
| | - Lanxiang Liu
- Department of Magnetic Resonance Imaging, Qinhuangdao Municipal No. 1 HospitalQinhuangdao, China
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Tham DKL, Moukhles H. Determining Cell-surface Expression and Endocytic Rate of Proteins in Primary Astrocyte Cultures Using Biotinylation. J Vis Exp 2017. [PMID: 28715371 DOI: 10.3791/55974] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
Cell-surface proteins mediate a wide array of functions. In many cases, their activity is regulated by endocytic processes that modulate their levels at the plasma membrane. Here, we present detailed protocols for 2 methods that facilitate the study of such processes, both of which are based on the principle of the biotinylation of cell-surface proteins. The first is designed to allow for the semi-quantitative determination of the relative levels of a particular protein at the cell-surface. In it, the lysine residues of the plasma membrane proteins of cells are first labeled with a biotin moiety. Once the cells are lysed, these proteins may then be specifically precipitated via the use of agarose-immobilized streptavidin by exploiting the natural affinity of the latter for biotin. The proteins isolated in such a manner may then be analyzed via a standard western blotting approach. The second method provides a means of determining the endocytic rate of a particular cell-surface target over a period of time. Cell-surface proteins are first modified with a biotin derivative containing a cleavable disulfide bond. The cells are then shifted back to normal culture conditions, which causes the endocytic uptake of a proportion of biotinylated proteins. Next, the disulfide bonds of non-internalized biotin groups are reduced using the membrane-impermeable reducing agent glutathione. Via this approach, endocytosed proteins may thus be isolated and quantified with a high degree of specificity.
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Affiliation(s)
- Daniel Kai Long Tham
- Department of Cellular and Physiological Sciences, University of British Columbia
| | - Hakima Moukhles
- Department of Cellular and Physiological Sciences, University of British Columbia;
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