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Martínez-Torres AM, Morán J. Aquaporin 4 and the endocannabinoid system: a potential therapeutic target in brain injury. Exp Brain Res 2024; 242:2041-2058. [PMID: 39043897 PMCID: PMC11306651 DOI: 10.1007/s00221-024-06896-7] [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: 02/20/2024] [Accepted: 07/14/2024] [Indexed: 07/25/2024]
Abstract
Brain edema is a critical complication arising from stroke and traumatic brain injury (TBI) with an important impact on patient recovery and can lead to long-term consequences. Therapeutic options to reduce edema progression are limited with variable patient outcomes. Aquaporin 4 (AQP4) is a water channel that allows bidirectional water diffusion across the astrocyte membrane and participates in the distinct phases of cerebral edema. The absence or inhibition of this channel has been demonstrated to ameliorate edema and brain damage. The endocannabinoid system (ECS) is a neuromodulator system with a wide expression in the brain and its activation has shown neuroprotective properties in diverse models of neuronal damage. This review describes and discusses the major features of ECS and AQP4 and their role during brain damage, observing that ECS stimulation reduces edema and injury size in diverse models of brain damage, however, the relationship between AQP4 expression and dynamics and ECS activation remains unclear. The research on these topics holds promising therapeutic implications for the treatment of brain edema following stroke and TBI.
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Affiliation(s)
- Ari Misael Martínez-Torres
- División de Neurociencias, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Coyoacán, Apartado Postal 70-253, 04510, Ciudad de Mexico, México
| | - Julio Morán
- División de Neurociencias, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Coyoacán, Apartado Postal 70-253, 04510, Ciudad de Mexico, México.
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2
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Hazell AS. Stem Cell Therapy and Thiamine Deficiency-Induced Brain Damage. Neurochem Res 2024; 49:1450-1467. [PMID: 38720090 DOI: 10.1007/s11064-024-04137-5] [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: 02/24/2023] [Revised: 01/18/2024] [Accepted: 03/15/2024] [Indexed: 05/21/2024]
Abstract
Wernicke's encephalopathy (WE) is a major central nervous system disorder resulting from thiamine deficiency (TD) in which a number of brain regions can develop serious damage including the thalamus and inferior colliculus. Despite decades of research into the pathophysiology of TD and potential therapeutic interventions, little progress has been made regarding effective treatment following the development of brain lesions and its associated cognitive issues. Recent developments in our understanding of stem cells suggest they are capable of repairing damage and improving function in different maladys. This article puts forward the case for the potential use of stem cell treatment as a therapeutic strategy in WE by first examining the effects of TD on brain functional integrity and its consequences. The second half of the paper will address the future benefits of treating TD with these cells by focusing on their nature and their potential to effectively treat neurodegenerative diseases that share some overlapping pathophysiological features with TD. At the same time, some of the obstacles these cells will have to overcome in order to become a viable therapeutic strategy for treating this potentially life-threatening illness in humans will be highlighted.
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Affiliation(s)
- Alan S Hazell
- Department of Medicine, University of Montreal, 2335 Bennett Avenue, Montreal, QC, H1V 2T6, Canada.
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3
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Zhao L, Hou S, Na R, Liu B, Wang Z, Li Y, Xie K. Prognostic role of serum ammonia in patients with sepsis-associated encephalopathy without hepatic failure. Front Public Health 2023; 10:1016931. [PMID: 36684934 PMCID: PMC9846324 DOI: 10.3389/fpubh.2022.1016931] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2022] [Accepted: 11/30/2022] [Indexed: 01/05/2023] Open
Abstract
Objectives Our previous study shows that serum ammonia in sepsis patients without hepatic failure is associated with a poor prognosis. The relationship between serum ammonia level and the prognosis of sepsis-associated encephalopathy (SAE) patients without hepatic failure remains unclear. We aimed to explore the relationship between serum ammonia levels and the prognosis of patients with SAE. Materials and methods This study is a retrospective cohort study. We collected 465 patients with SAE admitted to the intensive care unit (ICU) from Medical Information Mart for Intensive Care IV (MIMIC IV) from 2008 to 2019. Patients with SAE were divided into a survival group (369 patients) and a non-survival group (96 patients). We used the Wilcoxon signed-rank test and the multivariate logistic regression analysis to analyze the relationship between serum ammonia levels and the prognosis of patients with SAE. R software was used to analyze the dataset. Results The primary outcome was the relationship between serum ammonia level and hospital mortality of SAE. The secondary outcomes were the relationship between serum ammonia level and hospital stays, simplified acute physiology score (SAPS II), Charlson, Glasgow coma scale (GCS), sequential organ failure assessment (SOFA), and lactate level of SAE. The mortality of patients with SAE was 20.6%. The serum ammonia level was not significantly associated with hospital mortality, longer hospital stays, higher SAPS II and Charlson scores, and lower GCS of patients with SAE. The serum ammonia level was associated with higher SOFA scores and lactate levels in patients with SAE. The SAPS II and Charlson scores were independent risk factors for death in patients with SAE. Conclusion Serum ammonia level was associated with higher SOFA scores and lactate levels in patients with SAE. In addition, the SAPS II and Charlson scores can be used to assess the prognosis of patients with SAE. Therefore, we should closely monitor serum ammonia, SAPS II, and Charlson levels in patients with SAE.
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Affiliation(s)
- Lina Zhao
- Department of Critical Care Medicine, Tianjin Medical University General Hospital, Tianjin, China
| | - Shaowei Hou
- School of Biomedical Engineering and Technology, Tianjin Medical University, Tianjin, China
| | - Risu Na
- Department of Science and Education Department, Chifeng Municipal Hospital, Chifeng Clinical Medical College of Inner Mongolia Medical University, Chifeng, China
| | - Bin Liu
- Department of Emergency Chongqing University Central Hospital, Chongqing Emergency Medical Center, Chongqing, China
| | - Zhiwei Wang
- Department of Critical Care Medicine, Tianjin Medical University General Hospital, Tianjin, China
| | - Yun Li
- Department of Anesthesiology, Tianjin Institute of Anesthesiology, Tianjin Medical University General Hospital, Tianjin, China
| | - Keliang Xie
- Department of Critical Care Medicine, Tianjin Medical University General Hospital, Tianjin, China
- Department of Anesthesiology, Tianjin Institute of Anesthesiology, Tianjin Medical University General Hospital, Tianjin, China
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4
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Martínez N, Damiano AE. Aquaporins in Fetal Development. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2023; 1398:251-266. [PMID: 36717499 DOI: 10.1007/978-981-19-7415-1_17] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Water homeostasis is essential for fetal growth, and it depends on the successful development of the placenta. Many aquaporins (AQPs) were identified from blastocyst stages to term placenta. In the last years, cytokines, hormones, second messengers, intracellular pH, and membrane proteins were found to regulate their expression and function in the human placenta and fetal membranes. Accumulated data suggest that these proteins may be involved not only in the maintenance of the amniotic fluid volume homeostasis but also in the development of the placenta and fetal organs. In this sense, dysregulation of placental AQPs is associated with gestational disorders. Thus, current evidence shows that AQPs may collaborate in cellular events including trophoblast migration and apoptosis. In addition, aquaglyceroporins are involved in energy metabolism as well as urea elimination across the placenta. In the last year, the presence of AQP9 in trophoblast mitochondria opened new hypotheses about its role in pregnancy. However, much further work is needed to understand the importance of these proteins in human pregnancies.
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Affiliation(s)
- Nora Martínez
- Laboratorio de Biología de la Reproducción, Instituto de Fisiología y Biofísica Bernardo Houssay (IFIBIO)-CONICET-Facultad de Medicina, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Alicia E Damiano
- Laboratorio de Biología de la Reproducción, Instituto de Fisiología y Biofísica Bernardo Houssay (IFIBIO)-CONICET-Facultad de Medicina, Universidad de Buenos Aires, Buenos Aires, Argentina.
- Cátedra de Biología Celulary Molecular, Departamento de Ciencias Biológicas. Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Buenos Aires, Argentina.
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5
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Elsherbini DMA, Ghoneim FM, El-Mancy EM, Ebrahim HA, El-Sherbiny M, El-Shafey M, Al-Serwi RH, Elsherbiny NM. Astrocytes profiling in acute hepatic encephalopathy: Possible enrolling of glial fibrillary acidic protein, tumor necrosis factor-alpha, inwardly rectifying potassium channel (Kir 4.1) and aquaporin-4 in rat cerebral cortex. Front Cell Neurosci 2022; 16:896172. [PMID: 36060277 PMCID: PMC9428715 DOI: 10.3389/fncel.2022.896172] [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: 03/14/2022] [Accepted: 07/18/2022] [Indexed: 11/13/2022] Open
Abstract
Hepatic encephalopathy (HE) is a neurological disarray manifested as a sequel to chronic and acute liver failure (ALF). A potentially fatal consequence of ALF is brain edema with concomitant astrocyte enlargement. This study aims to outline the role of astrocytes in acute HE and shed light on the most critical mechanisms driving this role. Rats were allocated into two groups. Group 1, the control group, received the vehicle. Group 2, the TAA group, received TAA (300 mg/kg) for 3 days. Serum AST, ALT, and ammonia were determined. Liver and cerebral cortical sections were processed for hematoxylin and eosin staining. Additionally, mRNA expression and immunohistochemical staining of cortical GFAP, TNFα, Kir4.1, and AQP4 were performed. Cortical sections from the TAA group demonstrated neuropil vacuolation and astrocytes enlargement with focal gliosis. GFAP, TNFα, and AQP4 revealed increased mRNA expression, positive immunoreactivity, and a positive correlation to brain water content. In contrast, Kir 4.1 showed decreased mRNA expression and immunoreactivity and a negative correlation to brain water content. In conclusion, our findings revealed altered levels of TNFα, Kir 4.1, GFAP, and AQP4 in HE-associated brain edema. A more significant dysregulation of Kir 4.1 and TNFα was observed compared to AQP4 and GFAP.
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Affiliation(s)
- Dalia Mahmoud Abdelmonem Elsherbini
- Department of Clinical Laboratory Sciences, College of Applied Medical Sciences, Jouf University, Sakaka, Saudi Arabia
- Department of Anatomy, Faculty of Medicine, Mansoura University, Mansoura, Egypt
- *Correspondence: Dalia Mahmoud Abdelmonem Elsherbini,
| | - Fatma M. Ghoneim
- Department of Histology and Cell Biology, Faculty of Medicine, Mansoura University, Mansoura, Egypt
| | - Eman Mohammed El-Mancy
- Deanship of Common First Year, Jouf University, Sakaka, Saudi Arabia
- Department of Zoology, Faculty of Women for Arts, Science and Education, Ain Shams University, Cairo, Egypt
| | - Hasnaa Ali Ebrahim
- Department of Anatomy, Faculty of Medicine, Mansoura University, Mansoura, Egypt
| | - Mohamed El-Sherbiny
- Department of Basic Medical Sciences, College of Medicine, AlMaarefa University, Riyadh, Saudi Arabia
- Mohamed El-Sherbiny,
| | - Mohamed El-Shafey
- Department of Anatomy, Faculty of Medicine, Mansoura University, Mansoura, Egypt
- Department of Physiological Sciences, Fakeeh College for Medical Sciences, Jeddah, Saudi Arabia
| | - Rasha Hamed Al-Serwi
- Department of Basic Dental Sciences, College of Dentistry, Princess Nourah bint Abdulrahman University, Riyadh, Saudi Arabia
| | - Nehal M. Elsherbiny
- Department of Pharmaceutical Chemistry, Faculty of Pharmacy, University of Tabuk, Tabuk, Saudi Arabia
- Department of Biochemistry, Faculty of Pharmacy, Mansoura University, Mansoura, Egypt
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6
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Zhao L, Li Y, Wang Y, Ge Z, Zhu H, Zhou X, Li Y. Non-hepatic Hyperammonemia: A Potential Therapeutic Target for Sepsis-associated Encephalopathy. CNS & NEUROLOGICAL DISORDERS DRUG TARGETS 2022; 21:738-751. [PMID: 34939553 DOI: 10.2174/1871527321666211221161534] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/17/2021] [Revised: 10/10/2021] [Accepted: 10/26/2021] [Indexed: 11/22/2022]
Abstract
Sepsis-Associated Encephalopathy (SAE) is a common complication in the acute phase of sepsis, and patients who develop SAE have a higher mortality rate, longer hospital stay, and worse quality of life than other sepsis patients. Although the incidence of SAE is as high as 70% in sepsis patients, no effective treatment is available for this condition. To develop an effective treatment for SAE, it is vital to explore its pathogenesis. It is known that hyperammonemia is a possible factor in the pathogenesis of hepatic encephalopathy as ammonia is a potent neurotoxin. Furthermore, our previous studies indicate that non-hepatic hyperammonemia seems to occur more often in sepsis patients; it was also found that >50% of sepsis patients with non-hepatic hyperammonemia exhibited encephalopathy and delirium. Substatistical analyses indicate that non-hepatic hyperammonemia is an independent risk factor for SAE. This study updates the definition, clinical manifestations, and diagnosis of SAE; it also investigates the possible treatment options available for non-hepatic hyperammonemia in patients with sepsis and the mechanisms by which non-hepatic hyperammonemia causes encephalopathy.
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Affiliation(s)
- Lina Zhao
- Emergency Department, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing 100730, China
| | - Yun Li
- Department of Anesthesiology, Chifeng Municipal Hospital, Chifeng Clinical Medical College of Inner Mongolia Medical University, Chifeng 024000, China
| | - Yunying Wang
- Department of Critical Care Medicine, Chifeng Municipal Hospital, Chifeng Clinical Medical College of Inner Mongolia Medical University, Chifeng 024000, China
| | - Zengzheng Ge
- Emergency Department, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing 100730, China
| | - Huadong Zhu
- Emergency Department, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing 100730, China
| | - Xiuhua Zhou
- Department of Critical Care Medicine, The Fourth Affiliated Hospital of China Medical University, Shenyang 110032, China
| | - Yi Li
- Emergency Department, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing 100730, China
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7
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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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8
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Wang N, Zhang SN, Xing RJ, Liu MQ, Huang CN, Jiang SM, Li T, Yang CS, Yang L, Zhang LJ. Cerebrospinal fluid lactate level in aquaporin-4 antibody positive neuromyelitis optica spectrum disorders: a hint on differential diagnosis and possible immunopathogenesis. Mult Scler Relat Disord 2020; 47:102629. [PMID: 33232908 DOI: 10.1016/j.msard.2020.102629] [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: 11/08/2020] [Accepted: 11/13/2020] [Indexed: 10/23/2022]
Abstract
BACKGROUND Neuromyelitis optica spectrum disorders (NMOSD) and multiple sclerosis (MS) may be similar to each other in clinical features. The differential diagnosis between them remains challenging in clinical practice. This retrospective study is aimed to describe the difference of cerebrospinal fluid (CSF) lactate level between aquaporin-4 antibody (AQP4-Ab) positive NMOSD and MS, to discuss the possible explanation upon immunopathogenesis and the significance in differential diagnosis. METHOD We retrospectively analysed cerebral biochemical results from 60 AQP4-Ab positive NMOSD and 55 MS Asian patients. To assess the diagnostic ability of cerebrospinal fluid lactate for distinguishing AQP4-Ab positive NMOSD from MS using receiver operating characteristic (ROC) curve analysis. RESULTS The cerebrospinal fluid lactate level is significantly higher in AQP4-Ab positive NMOSD than in MS based on multiple linear regression (P<0.0001). The differential diagnostic efficacy of cerebrospinal fluid lactate distinguishing AQP4-Ab positive NMOSD from MS reached an area under ROC curve (AUC) of 0.8842 (95% CI 0.82-0.95, P<0.0001), using 1.50 as the diagnostic critical point of the cerebrospinal fluid lactate level, the sensitivity was 88.3%, the specificity was 78.2%. CONCLUSION The cerebrospinal fluid lactate level differs between AQP4-Ab positive NMOSD and MS, which also contributes in differential diagnosis. The distinct patterns of cerebral biochemical results may cast a light on the immunopathogenesis of AQP4-Ab positive NMOSD.
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Affiliation(s)
- Nan Wang
- Department of Neurology, Tianjin Neurological Institute, Tianjin Medical University General Hospital, No.154 Anshan Road, Heping District, Tianjin 300052, China
| | - Sheng-Nan Zhang
- Department of Neurology, Tianjin Neurological Institute, Tianjin Medical University General Hospital, No.154 Anshan Road, Heping District, Tianjin 300052, China
| | - Rong-Jun Xing
- Department of Neurology, Tianjin Neurological Institute, Tianjin Medical University General Hospital, No.154 Anshan Road, Heping District, Tianjin 300052, China
| | - Ming-Qi Liu
- Department of Neurology, Tianjin Neurological Institute, Tianjin Medical University General Hospital, No.154 Anshan Road, Heping District, Tianjin 300052, China
| | - Chen-Na Huang
- Department of Neurology, Tianjin Neurological Institute, Tianjin Medical University General Hospital, No.154 Anshan Road, Heping District, Tianjin 300052, China
| | - Shu-Min Jiang
- Department of Neurology, Tianjin Neurological Institute, Tianjin Medical University General Hospital, No.154 Anshan Road, Heping District, Tianjin 300052, China
| | - Ting Li
- Department of Neurology, Tianjin Neurological Institute, Tianjin Medical University General Hospital, No.154 Anshan Road, Heping District, Tianjin 300052, China
| | - Chun-Sheng Yang
- Department of Neurology, Tianjin Neurological Institute, Tianjin Medical University General Hospital, No.154 Anshan Road, Heping District, Tianjin 300052, China
| | - Li Yang
- Department of Neurology, Tianjin Neurological Institute, Tianjin Medical University General Hospital, No.154 Anshan Road, Heping District, Tianjin 300052, China
| | - Lin-Jie Zhang
- Department of Neurology, Tianjin Neurological Institute, Tianjin Medical University General Hospital, No.154 Anshan Road, Heping District, Tianjin 300052, China.
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9
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Thoman ME, McKarns SC. Metabolomic Profiling in Neuromyelitis Optica Spectrum Disorder Biomarker Discovery. Metabolites 2020; 10:metabo10090374. [PMID: 32961928 PMCID: PMC7570337 DOI: 10.3390/metabo10090374] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Revised: 09/04/2020] [Accepted: 09/12/2020] [Indexed: 12/21/2022] Open
Abstract
There is no specific test for diagnosing neuromyelitis optica spectrum disorder (NMOSD), a disabling autoimmune disease of the central nervous system. Instead, diagnosis relies on ruling out other related disorders with overlapping clinical symptoms. An urgency for NMOSD biomarker discovery is underscored by adverse responses to treatment following misdiagnosis and poor prognosis following the delayed onset of treatment. Pathogenic autoantibiotics that target the water channel aquaporin-4 (AQP4) and myelin oligodendrocyte glycoprotein (MOG) contribute to NMOSD pathology. The importance of early diagnosis between AQP4-Ab+ NMOSD, MOG-Ab+ NMOSD, AQP4-Ab− MOG-Ab− NMOSD, and related disorders cannot be overemphasized. Here, we provide a comprehensive data collection and analysis of the currently known metabolomic perturbations and related proteomic outcomes of NMOSD. We highlight short chain fatty acids, lipoproteins, amino acids, and lactate as candidate diagnostic biomarkers. Although the application of metabolomic profiling to individual NMOSD patient care shows promise, more research is needed.
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Affiliation(s)
- Maxton E. Thoman
- Department of Surgery, University of Missouri School of Medicine, Columbia, MO 65212, USA;
- Laboratory of TGF-β Biology, Epigenetics, and Cytokine Regulation, Department of Surgery, University of Missouri School of Medicine, Columbia, MO 65212, USA
| | - Susan C. McKarns
- Department of Surgery, University of Missouri School of Medicine, Columbia, MO 65212, USA;
- Laboratory of TGF-β Biology, Epigenetics, and Cytokine Regulation, Department of Surgery, University of Missouri School of Medicine, Columbia, MO 65212, USA
- Department of Microbiology and Immunology, University of Missouri School of Medicine, Columbia, MO 65212, USA
- Correspondence:
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10
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Guo H, Yin A, Ma Y, Fan Z, Tao L, Tang W, Ma Y, Hou W, Cai G, Zhuo L, Zhang J, Li Y, Xiong L. Astroglial N-myc downstream-regulated gene 2 protects the brain from cerebral edema induced by stroke. Glia 2020; 69:281-295. [PMID: 32652708 PMCID: PMC7754347 DOI: 10.1002/glia.23888] [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: 12/05/2018] [Revised: 06/16/2020] [Accepted: 06/26/2020] [Indexed: 01/14/2023]
Abstract
Brain edema is a grave complication of brain ischemia and is the main cause of herniation and death. Although astrocytic swelling is the main contributor to cytotoxic edema, the molecular mechanism involved in this process remains elusive. N‐myc downstream‐regulated gene 2 (NDRG2), a well‐studied tumor suppressor gene, is mainly expressed in astrocytes in mammalian brains. Here, we found that NDRG2 deficiency leads to worsened cerebral edema, imbalanced Na+ transfer, and astrocyte swelling after ischemia. We also found that NDRG2 deletion in astrocytes dramatically changed the expression and distribution of aquaporin‐4 and Na+‐K+‐ATPase β1, which are strongly associated with cell polarity, in the ischemic brain. Brain edema and astrocyte swelling were significantly alleviated by rescuing the expression of astrocytic Na+‐K+‐ATPase β1 in NDRG2‐knockout mouse brains. In addition, the upregulation of astrocytic NDRG2 by lentiviral constructs notably attenuated brain edema, astrocytic swelling, and blood–brain barrier destruction. Our results indicate a particular role of NDRG2 in maintaining astrocytic polarization to facilitate Na+ and water transfer balance and to protect the brain from ischemic edema. These findings provide insight into NDRG2 as a therapeutic target in cerebral edema.
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Affiliation(s)
- Hang Guo
- Department of Anesthesiology, The Seventh Medical Center of Chinese PLA General Hospital, Beijing, China.,Department of Anesthesiology and Perioperative Medicine, Xijing Hospital, The Air Force Military Medical University, Xi'an, China
| | - Anqi Yin
- Department of Anesthesiology and Perioperative Medicine, Xijing Hospital, The Air Force Military Medical University, Xi'an, China.,Department of Anesthesiology, Jinling Hospital, Nanjing, China
| | - Yulong Ma
- Anesthesia and Operation Center, The First Medical Center of Chinese PLA General Hospital, Beijing, China
| | - Ze Fan
- Department of Anesthesiology and Perioperative Medicine, Xijing Hospital, The Air Force Military Medical University, Xi'an, China
| | - Liang Tao
- Department of Anesthesiology and Perioperative Medicine, Xijing Hospital, The Air Force Military Medical University, Xi'an, China
| | - Wenhong Tang
- Department of Anesthesiology, The 960th Hospital of PLA, Jinan, China
| | - Yaqun Ma
- Department of Anesthesiology, The Seventh Medical Center of Chinese PLA General Hospital, Beijing, China
| | - Wugang Hou
- Department of Anesthesiology and Perioperative Medicine, Xijing Hospital, The Air Force Military Medical University, Xi'an, China
| | - Guohong Cai
- Institute of Neuroscience, The Air Force Military Medical University, Xi'an, China
| | - Lixia Zhuo
- Department of Anesthesiology & Center for Brain Science, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, China
| | - Jian Zhang
- Department of Biochemistry and Molecular Biology, The Air Force Military Medical University, Xi'an, China
| | - Yan Li
- Department of Anesthesiology and Perioperative Medicine, Xijing Hospital, The Air Force Military Medical University, Xi'an, China.,Department of Anesthesiology & Center for Brain Science, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, China
| | - Lize Xiong
- Department of Anesthesiology and Perioperative Medicine, Xijing Hospital, The Air Force Military Medical University, Xi'an, China.,Department of Anesthesiology & Translational Research Institute of Brain and Brain-Like Intelligence, Shanghai Fourth People's Hospital, Tongji University School of Medicine, Shanghai, China
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11
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Ye L, Xu Z, Deng J, Yang J. Classical Triad and Periventricular Lesions Do Not Necessarily Indicate Wernicke's Encephalopathy: A Case Report and Review of the Literature. Front Neurol 2020; 11:451. [PMID: 32587564 PMCID: PMC7297919 DOI: 10.3389/fneur.2020.00451] [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: 05/16/2019] [Accepted: 04/28/2020] [Indexed: 11/30/2022] Open
Abstract
The classical triad-ophthalmoplegia, cerebellar dysfunction, and altered mental state-in addition to bilateral symmetrical periventricular lesions are actually common to see, and clinicians tend to associate that with Wernicke's encephalopathy (WE). The diagnosis is strengthened with a likely deficiency of thiamine. We herein describe a malnourished patient with clinical triad and hyperintensities in the circumventricular regions, and she turned out to have neuromyelitis optica spectrum disorder (NMOSD) after many twists and turns. Despite totally different pathogenic mechanisms, NMOSD can mimic WE, sometimes even exhibiting radiological features similar to that of WE, thereby complicating the diagnosis. Our case highlights how similar these two diseases could be and the importance of differential diagnosis in clinical practice, which are so far rarely reported. Some clinical and radiological differences of these two diseases are summarized to help establish a prompt diagnosis.
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Affiliation(s)
- Lisha Ye
- Department of Neurology, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai, China
- School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Zhouwei Xu
- Department of Neurology, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai, China
- School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Jiangshan Deng
- Department of Neurology, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai, China
- School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Jiajun Yang
- Department of Neurology, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai, China
- School of Medicine, Shanghai Jiao Tong University, Shanghai, China
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Sepehrinezhad A, Zarifkar A, Namvar G, Shahbazi A, Williams R. Astrocyte swelling in hepatic encephalopathy: molecular perspective of cytotoxic edema. Metab Brain Dis 2020; 35:559-578. [PMID: 32146658 DOI: 10.1007/s11011-020-00549-8] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/21/2019] [Accepted: 02/12/2020] [Indexed: 02/06/2023]
Abstract
Hepatic encephalopathy (HE) may occur in patients with liver failure. The most critical pathophysiologic mechanism of HE is cerebral edema following systemic hyperammonemia. The dysfunctional liver cannot eliminate circulatory ammonia, so its plasma and brain levels rise sharply. Astrocytes, the only cells that are responsible for ammonia detoxification in the brain, are dynamic cells with unique phenotypic properties that enable them to respond to small changes in their environment. Any pathological changes in astrocytes may cause neurological disturbances such as HE. Astrocyte swelling is the leading cause of cerebral edema, which may cause brain herniation and death by increasing intracranial pressure. Various factors may have a role in astrocyte swelling. However, the exact molecular mechanism of astrocyte swelling is not fully understood. This article discusses the possible mechanisms of astrocyte swelling which related to hyperammonia, including the possible roles of molecules like glutamine, lactate, aquaporin-4 water channel, 18 KDa translocator protein, glial fibrillary acidic protein, alanine, glutathione, toll-like receptor 4, epidermal growth factor receptor, glutamate, and manganese, as well as inflammation, oxidative stress, mitochondrial permeability transition, ATP depletion, and astrocyte senescence. All these agents and factors may be targeted in therapeutic approaches to HE.
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Affiliation(s)
- Ali Sepehrinezhad
- Department of Neuroscience, Faculty of Advanced Technologies in Medicine, Iran University of Medical Sciences (IUMS), Tehran, Iran
| | - Asadollah Zarifkar
- Shiraz Neuroscience Research Center and Department of Physiology, Shiraz University of Medical Sciences (SUMS), Shiraz, Iran
| | - Gholamreza Namvar
- Department of Neuroscience and Cognition, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Ali Shahbazi
- Department of Neuroscience, Faculty of Advanced Technologies in Medicine, Iran University of Medical Sciences (IUMS), Tehran, Iran.
- Cellular and Molecular Research Center, Iran University of Medical Sciences (IUMS), Tehran, Iran.
| | - Roger Williams
- The Institute of Hepatology London and Foundation for Liver Research, 111 Coldharbour Lane, London, SE5 9NT, UK.
- Faculty of Life Sciences & Medicine, King's College London, London, UK.
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Politi MT, Ochoa F, Netti V, Ferreyra R, Bortman G, Sanjuan N, Morales C, Piazza A, Capurro C. Changes in cardiac Aquaporin expression during aortic valve replacement surgery with cardiopulmonary bypass. Eur J Cardiothorac Surg 2020; 57:556-564. [PMID: 31535145 DOI: 10.1093/ejcts/ezz249] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/23/2019] [Revised: 07/21/2019] [Accepted: 08/13/2019] [Indexed: 01/08/2023] Open
Abstract
OBJECTIVES Cardiopulmonary bypass (CPB) use is an essential strategy for many cardiovascular surgeries. However, its use and duration have been associated with a higher rate of postoperative complications, such as low cardiac output syndrome due to myocardial oedema and dysfunction. Though Aquaporin water channels have been implicated in myocardial water balance, their specific role in this clinical scenario has not been established. METHODS In a consecutive study of 17 patients with severe aortic stenosis undergoing aortic valve replacement surgery, 2 myocardial biopsies of the left ventricle were taken: 1 before and 1 after CPB use. Sociodemographic, clinical and laboratory data were collected. Western blot and immunohistochemistry studies were performed. RESULTS After CPB use, there was a mean increase of ∼62% in Aquaporin 1 protein levels (P = 0.001) and a mean reduction of ∼38% in Aquaporin 4 protein levels (P = 0.030). In immunohistochemistry assays, Aquaporin 1 was found lining small blood vessels, while Aquaporin 4 formed a circular label in cardiomyocytes. There were no changes in the localization of either protein following CPB use. During the observed on-pump time interval, there was a 1.7%/min mean increase in Aquaporin 1 (P = 0.021) and a 2.5%/min mean decrease in Aquaporin 4 (P = 0.018). Myocardial interstitial oedema increased by 42% (95% confidence interval 31-54%) after CPB use. Patients who developed low cardiac output syndrome were in the upper half of the median percentage change of Aquaporin expression. CONCLUSION Time-dependent changes in cardiac Aquaporin expression may be associated with myocardial oedema and dysfunction related to CPB use.
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Affiliation(s)
- María Teresa Politi
- School of Medicine, University of Buenos Aires, National Scientific and Technical Research Council, Institute of Physiology and Biophysics "Bernardo Houssay" (IFIBIO-HOUSSAY), Buenos Aires, Argentina
| | - Federico Ochoa
- School of Medicine, University of Buenos Aires, National Scientific and Technical Research Council, Institute of Physiology and Biophysics "Bernardo Houssay" (IFIBIO-HOUSSAY), Buenos Aires, Argentina
| | - Vanina Netti
- School of Medicine, University of Buenos Aires, National Scientific and Technical Research Council, Institute of Physiology and Biophysics "Bernardo Houssay" (IFIBIO-HOUSSAY), Buenos Aires, Argentina
| | - Raúl Ferreyra
- Department of Cardiology, Sanatorio de la Trinidad-Mitre, Buenos Aires, Argentina
| | - Guillermo Bortman
- Department of Cardiology, Sanatorio de la Trinidad-Mitre, Buenos Aires, Argentina
| | - Norberto Sanjuan
- Laboratory of Experimental Pathology, Department of Microbiology (IMPaM-CONICET), School of Medicine, University of Buenos Aires, National Scientific and Technical Research Council, Buenos Aires, Argentina
| | - Celina Morales
- School of Medicine, Facultad de Medicina, University of Buenos Aires, Institute of Cardiovascular Pathophysiology (INFICA), Buenos Aires, Argentina
| | - Antonio Piazza
- Department of Cardiovascular Surgery, Sanatorio de la Trinidad-Mitre, Buenos Aires, Argentina
| | - Claudia Capurro
- School of Medicine, University of Buenos Aires, National Scientific and Technical Research Council, Institute of Physiology and Biophysics "Bernardo Houssay" (IFIBIO-HOUSSAY), Buenos Aires, Argentina
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Abstract
Aquaporins (AQPs) are water channels proteins that facilitate water flux across cell membranes in response to osmotic gradients. Despite of the differences in the mammalian placentas, the conserved combination of AQPs expressed in placental and fetal membranes throughout gestation suggests that these proteins may be important in the regulation of fetal water homeostasis. Thus, AQPs may regulate the amniotic fluid volume and participate in the trans-placental transfer of water. Apart from their classical roles, recent studies have revealed that placental AQPs may also cooperate in cellular processes such as the migration and the apoptosis of the trophoblasts. Aquaglyceroporins can also participate in the energy metabolism and in the urea elimination across the placenta. Many factors including oxygen, hormones, acid-basis homeostasis, maternal dietary status, interaction with other transport proteins and osmotic stress are proposed to regulate their expression and function during gestation and alterations result in pathological pregnancies.
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Affiliation(s)
- Alicia E Damiano
- Laboratorio de Biología de la Reproducción, Instituto de Fisiología y Biofísica Bernardo Houssay (IFIBIO)-CONICET-Facultad de Medicina, Universidad de Buenos Aires, Buenos Aires, Argentina; Cátedra de Biología Celular y Molecular, Departamento de Ciencias Biológicas, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Buenos Aires, Argentina.
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Zhu S, Qiang J, Xia Q, Wang Y, Zhang J, Liu X. Hypothalamic sydrome as an initial presentation of Wernicke encephalopathy: A case report. Medicine (Baltimore) 2019; 98:e16181. [PMID: 31261554 PMCID: PMC6617480 DOI: 10.1097/md.0000000000016181] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/11/2019] [Revised: 04/28/2019] [Accepted: 06/03/2019] [Indexed: 01/18/2023] Open
Abstract
RATIONALE Wernicke encephalopathy (WE) is a syndrome characterized by an acute or subacute onset of ataxia, ophthalmoplegia, and mental status changes. To our knowledge, hypothalamic syndrome is rare in WE. PATIENT CONCERNS A 73-year-old female patient with acute cerebral infarct, who showed initial symptoms of vomiting, nausea, ataxia, and subsequent anorexia, was treated with parenteral nutritional supplement for 20 days. Nevertheless, the patient still developed refractory hyponatremia despite the appropriate sodium supplement given for a week following parenteral nutritional supplement. In fact, after 14 days of parenteral nutritional supplement, the patient gradually showed hypotension and apathy. Hyponatremia, hypotension, anorexia and apathy were signs of hypothalamic syndrome. DIAGNOSES Finally, the patient was diagnosed as WE by head magnetic resonance imaging, which showed symmetrical lesions in T2-weighted imaging images and FLAIR high signal intensity in the periaqueduct, hypothalamus, thalamus, mammiliary bodies, medulla oblongata, and vermis cerebelli. INTERVENTIONS The patient was given thiamine supplementation. OUTCOMES The patient regained consciousness within 3 days. The sings of hyponatremia, hypotension, and apathy were relieved subsequently. LESSONS When patients develop unexplained hypothalamic syndrome, we should think of the possibility of WE. The concomitant presence of hyponatremia, hypotension, anorexia, and apathy in WE is rare. Therefore, this case is reported here for discussion.
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Affiliation(s)
- Sha Zhu
- Department of Neurology, Peking University International Hospital
| | - Jun Qiang
- Department of Neurology, Peking University International Hospital
| | - Qing Xia
- Department of Neurology, Peking University International Hospital
| | - Yanshu Wang
- Department of Neurology, Peking University International Hospital
| | - Jun Zhang
- Department of Neurology, Peking University People's Hospital, Beijing, China
| | - Xianzeng Liu
- Department of Neurology, Peking University International Hospital
- Department of Neurology, Peking University People's Hospital, Beijing, China
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Zera K, Zastre J. Thiamine deficiency activates hypoxia inducible factor-1α to facilitate pro-apoptotic responses in mouse primary astrocytes. PLoS One 2017; 12:e0186707. [PMID: 29045486 PMCID: PMC5646851 DOI: 10.1371/journal.pone.0186707] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2017] [Accepted: 10/05/2017] [Indexed: 02/06/2023] Open
Abstract
Thiamine is an essential enzyme cofactor required for proper metabolic function and maintenance of metabolism and energy production in the brain. In developed countries, thiamine deficiency (TD) is most often manifested following chronic alcohol consumption leading to impaired mitochondrial function, oxidative stress, inflammation and excitotoxicity. These biochemical lesions result in apoptotic cell death in both neurons and astrocytes. Comparable histological injuries in patients with hypoxia/ischemia and TD have been described in the thalamus and mammillary bodies, suggesting a congruency between the cellular responses to these stresses. Consistent with hypoxia/ischemia, TD stabilizes and activates Hypoxia Inducible Factor-1α (HIF-1α) under physiological oxygen levels. However, the role of TD-induced HIF-1α in neurological injury is currently unknown. Using Western blot analysis and RT-PCR, we have demonstrated that TD induces HIF-1α expression and activity in primary mouse astrocytes. We observed a time-dependent increase in mRNA and protein expression of the pro-apoptotic and pro-inflammatory HIF-1α target genes MCP1, BNIP3, Nix and Noxa during TD. We also observed apoptotic cell death in TD as demonstrated by PI/Annexin V staining, TUNEL assay, and Cell Death ELISA. Pharmacological inhibition of HIF-1α activity using YC1 and thiamine repletion both reduced expression of pro-apoptotic HIF-1α target genes and apoptotic cell death in TD. These results demonstrate that induction of HIF-1α mediated transcriptional up-regulation of pro-apoptotic/inflammatory signaling contributes to astrocyte cell death during thiamine deficiency.
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Affiliation(s)
- Kristy Zera
- Department of Pharmaceutical and Biomedical Sciences, College of Pharmacy, University of Georgia, Athens, Georgia, United States of America
| | - Jason Zastre
- Department of Pharmaceutical and Biomedical Sciences, College of Pharmacy, University of Georgia, Athens, Georgia, United States of America
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Begum G, Song S, Wang S, Zhao H, Bhuiyan MIH, Li E, Nepomuceno R, Ye Q, Sun M, Calderon MJ, Stolz DB, St Croix C, Watkins SC, Chen Y, He P, Shull GE, Sun D. Selective knockout of astrocytic Na + /H + exchanger isoform 1 reduces astrogliosis, BBB damage, infarction, and improves neurological function after ischemic stroke. Glia 2017; 66:126-144. [PMID: 28925083 DOI: 10.1002/glia.23232] [Citation(s) in RCA: 73] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2017] [Revised: 08/25/2017] [Accepted: 08/29/2017] [Indexed: 01/25/2023]
Abstract
Stimulation of Na+ /H+ exchanger isoform 1 (NHE1) in astrocytes causes ionic dysregulation under ischemic conditions. In this study, we created a Nhe1flox/flox (Nhe1f/f ) mouse line with exon 5 of Nhe1 flanked with two loxP sites and selective ablation of Nhe1 in astrocytes was achieved by crossing Nhe1f/f mice with Gfap-CreERT2 Cre-recombinase mice. Gfap-CreERT2+/- ;Nhe1f/f mice at postnatal day 60-90 were treated with either corn oil or tamoxifen (Tam, 75 mg/kg/day, i.p.) for 5 days. After 30 days post-injection, mice underwent transient middle cerebral artery occlusion (tMCAO) to induce ischemic stroke. Compared with the oil-vehicle group (control), Tam-treated Gfap-CreERT2+/- ;Nhe1f/f (Nhe1 KO) mice developed significantly smaller ischemic infarction, less edema, and less neurological function deficits at 1-5 days after tMCAO. Immunocytochemical analysis revealed less astrocytic proliferation, less cellular hypertrophy, and less peri-lesion gliosis in Nhe1 KO mouse brains. Selective deletion of Nhe1 in astrocytes also reduced cerebral microvessel damage and blood-brain barrier (BBB) injury in ischemic brains. The BBB microvessels of the control brains show swollen endothelial cells, opened tight junctions, increased expression of proinflammatory protease MMP-9, and significant loss of tight junction protein occludin. In contrast, the Nhe1 KO mice exhibited reduced BBB breakdown and normal tight junction structure, with increased expression of occludin and reduced MMP-9. Most importantly, deletion of astrocytic Nhe1 gene significantly increased regional cerebral blood flow in the ischemic hemisphere at 24 hr post-MCAO. Taken together, our study provides the first line of evidence for a causative role of astrocytic NHE1 protein in reactive astrogliosis and ischemic neurovascular damage.
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Affiliation(s)
- Gulnaz Begum
- Department of Neurology, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Shanshan Song
- Department of Neurology, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Shaoxia Wang
- Department of Neurology, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Hanshu Zhao
- Department of Neurology, University of Pittsburgh, Pittsburgh, Pennsylvania
| | | | - Eric Li
- Department of Neurology, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Rachel Nepomuceno
- Department of Neurology, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Qing Ye
- Department of Neurology, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Ming Sun
- Department of Cell Biology, University of Pittsburgh, Pittsburgh, Pennsylvania
| | | | - Donna B Stolz
- Department of Cell Biology, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Claudette St Croix
- Department of Cell Biology, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Simon C Watkins
- Department of Cell Biology, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Yinhuai Chen
- Department of Molecular Genetics, Biochemistry and Microbiology, University of Cincinnati, Cincinnati, Ohio
| | - Pingnian He
- Department of Cellular and Molecular Physiology, Penn State Hershey College of Medicine, Hershey, Pennsylvania
| | - Gary E Shull
- Department of Molecular Genetics, Biochemistry and Microbiology, University of Cincinnati, Cincinnati, Ohio
| | - Dandan Sun
- Department of Neurology, University of Pittsburgh, Pittsburgh, Pennsylvania.,Veterans Affairs Pittsburgh Health Care System, Geriatric Research, Educational and Clinical Center, Pittsburgh, Pennsylvania
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18
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Onoda A, Takeda K, Umezawa M. Dose-dependent induction of astrocyte activation and reactive astrogliosis in mouse brain following maternal exposure to carbon black nanoparticle. Part Fibre Toxicol 2017; 14:4. [PMID: 28148272 PMCID: PMC5289048 DOI: 10.1186/s12989-017-0184-6] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2016] [Accepted: 01/20/2017] [Indexed: 11/24/2022] Open
Abstract
Background Recent studies indicate that maternal exposure to ambient ultrafine particles and nanoparticles has adverse effects of on the central nervous system. Quantitative dose–response data is required to better understand the developmental neurotoxicity of nanoparticles. The present study investigated dose-dependent effects of maternal exposure to carbon black nanoparticle (CB-NP) on astrocyte in the brains of mouse offspring. Methods A CB-NP suspension (2.9, 15, or 73 μg/kg) was intranasally administered to pregnant ICR mice on gestational days 5 and 9. Cerebral cortex samples were collected from 6-week-old offspring and examined by Western blotting, immunostaining, microarray analysis, and quantitative reverse transcriptase-polymerase chain reaction. Placentae were collected from pregnant dams on gestational day 13 and examined by microarray analysis. Results Maternal exposure to CB-NP induced a dose-dependent increase in glial fibrillary acidic protein (GFAP) expression in the cerebral cortex; this increase was particularly observed in astrocytic end-feet attached to denatured perivascular macrophages. Moreover, maternal CB-NP exposure dose-dependently increased aquaporin-4 expression in the brain parenchyma region around blood vessels. The changes in the expression profiles of GFAP and Aqp4 in offspring after maternal CB-NP exposure were similar to those observed in mice of a more advanced age. The expression levels of mRNAs associated with angiogenesis, cell migration, proliferation, chemotaxis, and growth factor production were also altered in the cerebral cortex of offspring after maternal CB-NP exposure. Differentially expressed genes in placental tissues after CB-NP exposure did not populate any specific gene ontology category. Conclusions Maternal CB-NP exposure induced long-term activation of astrocytes resulting in reactive astrogliosis in the brains of young mice. Our observations suggest a potentially increased risk of the onset of age-related neurodegenerative diseases by maternal NP exposure. In this study, we report for the first time a quantitative dose–response relationship between maternal NP exposure and phenotypic changes in the central nervous system of the offspring. Moreover, our findings indicate that cortical GFAP and Aqp4 are useful biomarkers that can be employed in further studies aiming to elucidate the underlying mechanism of nanoparticle-mediated developmental neurotoxicity.
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Affiliation(s)
- Atsuto Onoda
- Department of Hygienic Chemistry, Graduate School of Pharmaceutical Sciences, Tokyo University of Science, 2641 Yamazaki, Noda, Chiba, 278-8510, Japan. .,The Center for Environmental Health Science for the Next Generation, Research Institute for Science and Technology, Organization for Research Advancement, Tokyo University of Science, 2641 Yamazaki, Noda, Chiba, 278-8510, Japan. .,Research Fellow of Japan Society for the Promotion of Science, 5-3-1 Kouji-machi, Chiyoda-ku, Tokyo, 102-0083, Japan.
| | - Ken Takeda
- The Center for Environmental Health Science for the Next Generation, Research Institute for Science and Technology, Organization for Research Advancement, Tokyo University of Science, 2641 Yamazaki, Noda, Chiba, 278-8510, Japan
| | - Masakazu Umezawa
- The Center for Environmental Health Science for the Next Generation, Research Institute for Science and Technology, Organization for Research Advancement, Tokyo University of Science, 2641 Yamazaki, Noda, Chiba, 278-8510, Japan.,Department of Materials Science and Technology, Faculty of Industrial Science and Technology, Tokyo University of Science, 6-3-1 Niijuku, Katsushika, Tokyo, 125-8585, Japan
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20
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Park SJ, Jeong IH, Kong BS, Lee JE, Kim KH, Lee DY, Kim HJ. Disease Type- and Status-Specific Alteration of CSF Metabolome Coordinated with Clinical Parameters in Inflammatory Demyelinating Diseases of CNS. PLoS One 2016; 11:e0166277. [PMID: 27855220 PMCID: PMC5113962 DOI: 10.1371/journal.pone.0166277] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2016] [Accepted: 10/25/2016] [Indexed: 01/15/2023] Open
Abstract
Central nervous system (CNS) inflammatory demyelinating diseases (IDDs) are a group of disorders with different aetiologies, characterized by inflammatory lesions. These disorders include multiple sclerosis (MS), neuromyelitis optica spectrum disorder (NMOSD), and idiopathic transverse myelitis (ITM). Differential diagnosis of the CNS IDDs still remains challenging due to frequent overlap of clinical and radiological manifestation, leading to increased demands for new biomarker discovery. Since cerebrospinal fluid (CSF) metabolites may reflect the status of CNS tissues and provide an interfacial linkage between blood and CNS tissues, we explored multi-component biomarker for different IDDs from CSF samples using gas chromatography mass spectrometry-based metabolite profiling coupled to multiplex bioinformatics approach. We successfully constructed the single model with multiple metabolite variables in coordinated regression with clinical characteristics, expanded disability status scale, oligoclonal bands, and protein levels. The multi-composite biomarker simultaneously discriminated four different immune statuses (a total of 145 samples; 54 MS, 49 NMOSD, 30 ITM, and 12 normal controls). Furthermore, systematic characterization of transitional metabolic modulation identified relapse-associated metabolites and proposed insights into the disease network underlying type-specific metabolic dysfunctionality. The comparative analysis revealed the lipids, 1-monopalmitin and 1-monostearin were common indicative for MS, NMOSD, and ITM whereas fatty acids were specific for the relapse identified in all types of IDDs.
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Affiliation(s)
- Soo Jin Park
- The Department of Bio and Fermentation Convergence Technology, BK21 PLUS project, Kookmin University, Seoul, Korea
| | - In Hye Jeong
- The Department of Neurology, Research Institute and Hospital of the National Cancer Center, Goyang, Korea
| | - Byung Soo Kong
- The Department of Neurology, Research Institute and Hospital of the National Cancer Center, Goyang, Korea
| | - Jung-Eun Lee
- The Department of Bio and Fermentation Convergence Technology, BK21 PLUS project, Kookmin University, Seoul, Korea
| | - Kyoung Heon Kim
- The Department of Biotechnology, Graduate School, Korea University, Seoul, Korea
| | - Do Yup Lee
- The Department of Bio and Fermentation Convergence Technology, BK21 PLUS project, Kookmin University, Seoul, Korea
- * E-mail: (HJK); (DYL)
| | - Ho Jin Kim
- The Department of Neurology, Research Institute and Hospital of the National Cancer Center, Goyang, Korea
- * E-mail: (HJK); (DYL)
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Manchester LC, Lee V, Schmithorst V, Kochanek PM, Panigrahy A, Fink EL. Global and Regional Derangements of Cerebral Blood Flow and Diffusion Magnetic Resonance Imaging after Pediatric Cardiac Arrest. J Pediatr 2016; 169:28-35.e1. [PMID: 26561380 PMCID: PMC4729616 DOI: 10.1016/j.jpeds.2015.10.003] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/16/2015] [Revised: 08/19/2015] [Accepted: 10/01/2015] [Indexed: 01/06/2023]
Abstract
OBJECTIVE To quantify and examine the relationship between global and regional cerebral blood flow (CBF) and water diffusion on brain magnetic resonance imaging (MRI) in children after cardiac arrest. STUDY DESIGN Children admitted to a tertiary care children's hospital from July 2011 to April 2013 who received a brain MRI within 2 weeks after cardiac arrest that included arterial spin labeling and apparent diffusion coefficient (ADC) sequences were studied. CBF and ADC values were calculated globally and in 19 regions of interest. Outcome variables included survival and favorable neurologic outcome, which was defined as Pediatric Cerebral Performance Category ≤3 at 6 months. We examined global and regional relationships between CBF and ADC and their association with outcome. RESULTS This sample included 14 pediatric patients (mean time to MRI 6 ± 4 days), 9 of whom survived and 6 who survived with favorable outcome. Global ADC was significantly decreased in patients with unfavorable outcome (P = .02). Increased CBF and decreased ADC often were colocalized in the same region, especially in children who had unfavorable outcomes. CONCLUSIONS In this exploratory study, global restricted water diffusion on ADC after pediatric cardiac arrest was associated with unfavorable outcome. MRI assessments of perfusion and diffusion may have prognostic value after pediatric cardiac arrest.
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Affiliation(s)
| | - Vince Lee
- Department of Radiology, Children’s Hospital of Pittsburgh
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Dietrich V, Damiano AE. Activity of NA+/H+ exchangers alters aquaporin-mediated water transport in human placenta. Placenta 2015; 36:1487-9. [DOI: 10.1016/j.placenta.2015.09.014] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/30/2015] [Revised: 09/17/2015] [Accepted: 09/30/2015] [Indexed: 11/27/2022]
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Barrese V, Taglialatela M, Greenwood IA, Davidson C. Protective role of Kv7 channels in oxygen and glucose deprivation-induced damage in rat caudate brain slices. J Cereb Blood Flow Metab 2015; 35:1593-600. [PMID: 25966943 PMCID: PMC4640310 DOI: 10.1038/jcbfm.2015.83] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/19/2014] [Revised: 03/09/2015] [Accepted: 04/09/2015] [Indexed: 11/09/2022]
Abstract
Ischemic stroke can cause striatal dopamine efflux that contributes to cell death. Since Kv7 potassium channels regulate dopamine release, we investigated the effects of their pharmacological modulation on dopamine efflux, measured by fast cyclic voltammetry (FCV), and neurotoxicity, in Wistar rat caudate brain slices undergoing oxygen and glucose deprivation (OGD). The Kv7 activators retigabine and ICA27243 delayed the onset, and decreased the peak level of dopamine efflux induced by OGD; and also decreased OGD-induced damage measured by 2,3,5-triphenyltetrazolium chloride (TTC) staining. Retigabine also reduced OGD-induced necrotic cell death evaluated by lactate dehydrogenase activity assay. The Kv7 blocker linopirdine increased OGD-evoked dopamine efflux and OGD-induced damage, and attenuated the effects of retigabine. Quantitative-PCR experiments showed that OGD caused an ~6-fold decrease in Kv7.2 transcript, while levels of mRNAs encoding for other Kv7 subunits were unaffected; western blot experiments showed a parallel reduction in Kv7.2 protein levels. Retigabine also decreased the peak level of dopamine efflux induced by L-glutamate, and attenuated the loss of TTC staining induced by the excitotoxin. These results suggest a role for Kv7.2 in modulating ischemia-evoked caudate damage.
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Affiliation(s)
- Vincenzo Barrese
- Division of Biomedical Sciences, St George's University of London, London, UK.,Department of Neuroscience Reproductive Sciences and Odontostomatology, University of Naples Federico II, Naples, Italy
| | - Maurizio Taglialatela
- Department of Neuroscience Reproductive Sciences and Odontostomatology, University of Naples Federico II, Naples, Italy.,Department of Medicine and Health Science, University of Molise, Campobasso, Italy
| | - Iain A Greenwood
- Division of Biomedical Sciences, St George's University of London, London, UK
| | - Colin Davidson
- Division of Biomedical Sciences, St George's University of London, London, UK
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Vella J, Zammit C, Di Giovanni G, Muscat R, Valentino M. The central role of aquaporins in the pathophysiology of ischemic stroke. Front Cell Neurosci 2015; 9:108. [PMID: 25904843 PMCID: PMC4389728 DOI: 10.3389/fncel.2015.00108] [Citation(s) in RCA: 84] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2015] [Accepted: 04/10/2015] [Indexed: 11/16/2022] Open
Abstract
Stroke is a complex and devastating neurological condition with limited treatment options. Brain edema is a serious complication of stroke. Early edema formation can significantly contribute to infarct formation and thus represents a promising target. Aquaporin (AQP) water channels contribute to water homeostasis by regulating water transport and are implicated in several disease pathways. At least 7 AQP subtypes have been identified in the rodent brain and the use of transgenic mice has greatly aided our understanding of their functions. AQP4, the most abundant channel in the brain, is up-regulated around the peri-infarct border in transient cerebral ischemia and AQP4 knockout mice demonstrate significantly reduced cerebral edema and improved neurological outcome. In models of vasogenic edema, brain swelling is more pronounced in AQP4-null mice than wild-type providing strong evidence of the dual role of AQP4 in the formation and resolution of both vasogenic and cytotoxic edema. AQP4 is co-localized with inwardly rectifying K(+)-channels (Kir4.1) and glial K(+) uptake is attenuated in AQP4 knockout mice compared to wild-type, indicating some form of functional interaction. AQP4-null mice also exhibit a reduction in calcium signaling, suggesting that this channel may also be involved in triggering pathological downstream signaling events. Associations with the gap junction protein Cx43 possibly recapitulate its role in edema dissipation within the astroglial syncytium. Other roles ascribed to AQP4 include facilitation of astrocyte migration, glial scar formation, modulation of inflammation and signaling functions. Treatment of ischemic cerebral edema is based on the various mechanisms in which fluid content in different brain compartments can be modified. The identification of modulators and inhibitors of AQP4 offer new therapeutic avenues in the hope of reducing the extent of morbidity and mortality in stroke.
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Affiliation(s)
| | | | | | | | - Mario Valentino
- Department of Physiology and Biochemistry, University of MaltaMsida, Malta
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25
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Afadlal S, Labetoulle R, Hazell AS. Role of astrocytes in thiamine deficiency. Metab Brain Dis 2014; 29:1061-8. [PMID: 24929329 DOI: 10.1007/s11011-014-9571-y] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/11/2014] [Accepted: 05/20/2014] [Indexed: 12/21/2022]
Abstract
Thiamine deficiency (TD) is the underlying cause of Wernicke's encephalopathy (WE), an acute neurological disorder characterized by structural damage to key periventricular structures in the brain. Increasing evidence suggests these focal histological lesions may be representative of a gliopathy in which astrocyte-related changes are a major feature of the disorder. These changes include a loss of the glutamate transporters GLT-1 and GLAST concomitant with elevated interstitial glutamate levels, lowered brain pH associated with increased lactate production, decreased levels of GFAP, reduction in the levels of glutamine synthetase, swelling, alterations in levels of aquaporin-4, and disruption of the blood-brain barrier. This review focusses on how these manifestations contribute to the pathophysiology of TD and possibly WE.
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Affiliation(s)
- Szeifoul Afadlal
- Departamento de Neurologia, Universidade Estadual de Campinas (UNICAMP), Campinas, SP, Brazil
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26
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Abdou E, Hazell AS. Thiamine deficiency: an update of pathophysiologic mechanisms and future therapeutic considerations. Neurochem Res 2014; 40:353-61. [PMID: 25297573 DOI: 10.1007/s11064-014-1430-z] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2014] [Revised: 09/02/2014] [Accepted: 09/03/2014] [Indexed: 12/17/2022]
Abstract
Thiamine is an essential vitamin that is necessary to maintain the functional integrity of cells in the brain. Its deficiency is the underlying cause of Wernicke's encephalopathy (WE), a disorder primarily associated with, but not limited to, chronic alcoholism. Thiamine deficiency leads to the development of impaired energy metabolism due to mitochondrial dysfunction in focal regions of the brain resulting in cerebral vulnerability. The consequences of this include oxidative stress, excitotoxicity, inflammatory responses, decreased neurogenesis, blood-brain barrier disruption, lactic acidosis and a reduction in astrocyte functional integrity involving a loss of glutamate transporters and other astrocyte-specific proteins which together contribute in a major way to the resulting neurodegeneration. Exactly how these factors acting in concert lead to the demise of neurons is unclear. In this review we reassess their relative importance in the light of more recent findings and discuss therapeutic possibilities that may provide hope for the future for individuals with WE.
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Affiliation(s)
- Eman Abdou
- Department of Medicine, University of Montreal, Montreal, QC, Canada
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27
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Neuroinflammation and neurodegeneration in adult rat brain from binge ethanol exposure: abrogation by docosahexaenoic acid. PLoS One 2014; 9:e101223. [PMID: 25029343 PMCID: PMC4100731 DOI: 10.1371/journal.pone.0101223] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2014] [Accepted: 06/04/2014] [Indexed: 12/18/2022] Open
Abstract
Evidence that brain edema and aquaporin-4 (AQP4) water channels have roles in experimental binge ethanol-induced neurodegeneration has stimulated interest in swelling/edema-linked neuroinflammatory pathways leading to oxidative stress. We report here that neurotoxic binge ethanol exposure produces comparable significant effects in vivo and in vitro on adult rat brain levels of AQP4 as well as neuroinflammation-linked enzymes: key phospholipase A2 (PLA2) family members and poly (ADP-ribose) polymerase-1 (PARP-1). In adult male rats, repetitive ethanol intoxication (3 gavages/d for 4 d, ∼9 g/kg/d, achieving blood ethanol levels ∼375 mg/dl; “Majchrowicz” model) significantly increased AQP4, Ca+2-dependent PLA2 GIVA (cPLA2), phospho-cPLA2 GIVA (p-cPLA2), secretory PLA2 GIIA (sPLA2) and PARP-1 in regions incurring extensive neurodegeneration in this model—hippocampus, entorhinal cortex, and olfactory bulb—but not in two regions typically lacking neurodamage, frontal cortex and cerebellum. Also, ethanol reduced hippocampal Ca+2-independent PLA2 GVIA (iPLA2) levels and increased brain “oxidative stress footprints” (4-hydroxynonenal-adducted proteins). For in vitro studies, organotypic cultures of rat hippocampal-entorhinocortical slices of adult age (∼60 d) were ethanol-binged (100 mM or ∼450 mg/dl) for 4 d, which augments AQP4 and causes neurodegeneration (Collins et al. 2013). Reproducing the in vivo results, cPLA2, p-cPLA2, sPLA2 and PARP-1 were significantly elevated while iPLA2 was decreased. Furthermore, supplementation with docosahexaenoic acid (DHA; 22:6n-3), known to quell AQP4 and neurodegeneration in ethanol-treated slices, blocked PARP-1 and PLA2 changes while counteracting endogenous DHA reduction and increases in oxidative stress footprints (3-nitrotyrosinated proteins). Notably, the PARP-1 inhibitor PJ-34 suppressed binge ethanol-dependent neurodegeneration, indicating PARP upstream involvement. The results with corresponding models support involvement of AQP4- and PLA2-associated neuroinflammatory pro-oxidative pathways in the neurodamage, with potential regulation by PARP-1 as well. Furthermore, DHA emerges as an effective inhibitor of these binge ethanol-dependent neuroinflammatory pathways as well as associated neurodegeneration in adult-age brain.
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Stokum JA, Kurland DB, Gerzanich V, Simard JM. Mechanisms of astrocyte-mediated cerebral edema. Neurochem Res 2014; 40:317-28. [PMID: 24996934 DOI: 10.1007/s11064-014-1374-3] [Citation(s) in RCA: 96] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2014] [Revised: 06/18/2014] [Accepted: 06/26/2014] [Indexed: 11/26/2022]
Abstract
Cerebral edema formation stems from disruption of blood brain barrier (BBB) integrity and occurs after injury to the CNS. Due to the restrictive skull, relatively small increases in brain volume can translate into impaired tissue perfusion and brain herniation. In excess, cerebral edema can be gravely harmful. Astrocytes are key participants in cerebral edema by virtue of their relationship with the cerebral vasculature, their unique compliment of solute and water transport proteins, and their general role in brain volume homeostasis. Following the discovery of aquaporins, passive conduits of water flow, aquaporin 4 (AQP4) was identified as the predominant astrocyte water channel. Normally, AQP4 is highly enriched at perivascular endfeet, the outermost layer of the BBB, whereas after injury, AQP4 expression disseminates to the entire astrocytic plasmalemma, a phenomenon termed dysregulation. Arguably, the most important role of AQP4 is to rapidly neutralize osmotic gradients generated by ionic transporters. In pathological conditions, AQP4 is believed to be intimately involved in the formation and clearance of cerebral edema. In this review, we discuss aquaporin function and localization in the BBB during health and injury, and we examine post-injury ionic events that modulate AQP4-dependent edema formation.
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Affiliation(s)
- Jesse A Stokum
- Department of Neurosurgery, University of Maryland School of Medicine, 22 S. Greene St., Suite S12D, Baltimore, MD, 21201-1595, USA
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29
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Jarius S, Wildemann B. Aquaporin-4 antibodies, CNS acidosis and neuromyelitis optica: a potential link. Med Hypotheses 2013; 81:1090-5. [PMID: 24182872 DOI: 10.1016/j.mehy.2013.10.011] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2013] [Revised: 09/17/2013] [Accepted: 10/09/2013] [Indexed: 12/12/2022]
Abstract
BACKGROUND Neuromyelitis optica (NMO, Devic's syndrome) is a severely disabling disorder of the central nervous system characterized by optic neuritis and longitudinally extensive myelitis. In around 80% of cases, NMO is caused by autoantibodies to astrocytic aquaporin-4 (AQP4), the most abundant water channel in the CNS. Acute NMO attacks are frequently accompanied by elevated levels of lactate in the cerebrospinal fluid (CSF). As a strongly dissociated anion (pK'=3.7) directly changing the strong ion difference, lactate causes a reduction in the dependent anion [HCO3-] and a rise in [H+], resulting in "metabolic" acidosis in the CSF. CSF acidosis also develops during respiratory failure due to brainstem or high cervical spinal cord lesions, the most common cause of death in NMO. However, lactic acid and more generally, a decrease in pH, has been shown to increase the membrane expression of AQP4 in astrocytes. An increase in AQP4 membrane expression during acute NMO attacks could potentially enhance the complement-mediated humoral immune reaction against AQP4-expressing astrocytes characteristic for NMO and, thus, result in more severe astrocytic damage. Moreover, lactate and acidosis have been shown to cause astrocytic swelling and to affect astrocytic viability, potentially rendering astrocytes more susceptible to AQP4-Ab-mediated damage. Finally, increased AQP4 expression could be an independent risk factor in NMO and other forms of CNS inflammation, as indicated by the finding of grossly attenuated experimental autoimmune encephalomyelitis in AQP4-null mice. Therefore, we hypothesize that CSF acidosis might play a role in the pathophysiology of AQP4-Ab-positive NMO and that alterations in CSF pH might possibly influence the outcome of acute attacks in this condition. In addition, we discuss potential clinical implications and make proposals on how to test the hypothesis. Finally, other factors that influence astrocytic AQP4 membrane expression and might play a role in NMO are discussed.
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Affiliation(s)
- S Jarius
- Division of Molecular Neuroimmunology, Department of Neurology, University of Heidelberg, Germany.
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30
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Hell M, Bernhofer C, Stalzer P, Kern JM, Claassen E. Probiotics in Clostridium difficile infection: reviewing the need for a multistrain probiotic. Benef Microbes 2013; 4:39-51. [PMID: 23434948 DOI: 10.3920/bm2012.0049] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
In the past two years an enormous amount of molecular, genetic, metabolomic and mechanistic data on the host-bacterium interaction, a healthy gut microbiota and a possible role for probiotics in Clostridium difficile infection (CDI) has been accumulated. Also, new hypervirulent strains of C. difficile have emerged. Yet, clinical trials in CDI have been less promising than in antibiotic associated diarrhoea in general, with more meta-analysis than primary papers on CDI-clinical-trials. The fact that C. difficile is a spore former, producing at least three different toxins has not yet been incorporated in the rational design of probiotics for (recurrent) CDI. Here we postulate that the plethora of effects of C. difficile and the vast amount of data on the role of commensal gut residents and probiotics point towards a multistrain mixture of probiotics to reduce CDI, but also to limit (nosocomial) transmission and/or endogenous reinfection. On the basis of a retrospective chart review of a series of ten CDI patients where recurrence was expected, all patients on adjunctive probiotic therapy with multistrain cocktail (Ecologic®AAD/OMNiBiOTiC® 10) showed complete clinical resolution. This result, and recent success in faecal transplants in CDI treatment, are supportive for the rational design of multistrain probiotics for CDI.
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Affiliation(s)
- M Hell
- Department of Hospital Epidemiology and Infection Control, Salzburg University Hospital, Paracelsus Medical University, Strubergasse 21, 5020 Salzburg, Austria
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31
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Castro-Parodi M, Szpilbarg N, Dietrich V, Sordelli M, Reca A, Abán C, Maskin B, Farina M, Damiano A. Oxygen tension modulates AQP9 expression in human placenta. Placenta 2013; 34:690-8. [DOI: 10.1016/j.placenta.2013.04.017] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/27/2012] [Revised: 03/29/2013] [Accepted: 04/24/2013] [Indexed: 12/31/2022]
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32
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Antidepressant acts on astrocytes leading to an increase in the expression of neurotrophic/growth factors: differential regulation of FGF-2 by noradrenaline. PLoS One 2012; 7:e51197. [PMID: 23227251 PMCID: PMC3515577 DOI: 10.1371/journal.pone.0051197] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2012] [Accepted: 10/29/2012] [Indexed: 01/27/2023] Open
Abstract
Recently, multiple neurotrophic/growth factors have been proposed to play an important role in the therapeutic action of antidepressants. In this study, we prepared astrocyte- and neuron-enriched cultures from the neonatal rat cortex, and examined the changes in neurotrophic/growth factor expression by antidepressant treatment using real-time PCR. Treatment with amitriptyline (a tricyclic antidepressant) significantly increased the expression of fibroblast growth factor-2 (FGF-2), brain-derived neurotrophic factor, vascular endothelial growth factor and glial cell line-derived neurotrophic factor mRNA with a different time course in astrocyte cultures, but not in neuron-enriched cultures. Only the expression of FGF-2 was higher in astrocyte cultures than in neuron-enriched cultures. We focused on the FGF-2 production in astrocytes. Several different classes of antidepressants, but not non-antidepressants, also induced FGF-2 mRNA expression. Noradrenaline (NA) is known to induce FGF-2 expression in astrocyte cultures, as with antidepressants. Therefore, we also assessed the mechanism of NA-induced FGF-2 expression, in comparison to amitriptyline. NA increased the FGF-2 mRNA expression via α1 and β-adrenergic receptors; however, the amitriptyline-induced FGF-2 mRNA expression was not mediated via these adrenergic receptors. Furthermore, the amitriptyline-induced FGF-2 mRNA expression was completely blocked by cycloheximide (an inhibitor of protein synthesis), while the NA-induced FGF-2 mRNA was not. These data suggest that the regulation of FGF-2 mRNA expression by amitriptyline was distinct from that by NA. Taken together, antidepressant-stimulated astrocytes may therefore be important mediators that produce several neurotrophic/growth factors, especially FGF-2, through a monoamine-independent and a de novo protein synthesis-dependent mechanism.
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33
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Docosahexaenoic acid (DHA) prevents binge ethanol-dependent aquaporin-4 elevations while inhibiting neurodegeneration: experiments in rat adult-age entorhino-hippocampal slice cultures. Neurotox Res 2012. [PMID: 23184649 DOI: 10.1007/s12640-012-9360-5] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Repetitive binge intoxication with ethanol (alcohol) in adult rats, mimicking chronic ethanol abuse in alcoholics, causes trauma-like brain edema and relatively selective neurodegeneration of hippocampal dentate granule cells and pyramidal neurons in the temporal cortex (especially entorhinal cortex). We have now modeled the aspects of this type of acquired brain damage in vitro with rat entorhino-hippocampal slice cultures of adult brain age (62 ± 3 days). When sequentially treated (four 16-h overnight exposures) with 100 mM ethanol, the slices display elevated levels of aquaporin-4 (AQP4) water channels accompanied by significant neurodegeneration. Increased AQP4 has been associated with neuroinflammatory responses including edema, pro-inflammatory cytokine elevations, arachidonic acid release, and oxidative stress. Co-treatment of ethanol-binged slice cultures with docosahexaenoic acid (DHA), an omega-3 fatty acid known to suppress brain damage from other insults, prevents both the AQP4 elevations and the neurodamage. Surmising that AQP4 augmentation is a causative neuroinflammatory component in this model, we are investigating several possibilities to explain the protective actions of the omega-3 fatty acid. Since the worldwide incidence of cognitive dysfunction and dementia from ethanol abuse and alcoholism is not inconsequential, DHA supplementation with chronic alcoholics could emerge to be a rational approach to potentially lessening brain disabilities.
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Bodega G, Suárez I, López-Fernández LA, García MI, Köber M, Penedo M, Luna M, Juárez S, Ciordia S, Oria M, Córdoba J, Fernández B. Ammonia induces aquaporin-4 rearrangement in the plasma membrane of cultured astrocytes. Neurochem Int 2012; 61:1314-24. [PMID: 23022607 DOI: 10.1016/j.neuint.2012.09.008] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2012] [Revised: 09/06/2012] [Accepted: 09/13/2012] [Indexed: 11/30/2022]
Abstract
Aquaporin-4 (AQP4) is a water channel protein mainly located in the astroglial plasma membrane, the precise function of which in the brain edema that accompanies hepatic encephalopathy (HE) is unclear. Since ammonia is the main pathogenic agent in HE, its effect on AQP4 expression and distribution in confluent primary astroglial cultures was examined via their exposure to ammonium chloride (1, 3 and 5 mM) for 5 and 10 days. Ammonia induced the general inhibition of AQP4 mRNA synthesis except in the 1 mM/5 day treatment. However, the AQP4 protein content measured was dependent on the method of analysis; an apparent increase was recorded in treated cells in in-cell Western assays, while an apparent reduction was seen with the classic Western blot method, perhaps due to differences in AQP4 aggregation. Ammonia might therefore induce the formation of insoluble AQP4 aggregates in the astroglial plasma membrane. The finding of AQP4 in the pellet of classic Western blot samples, plus data obtained via confocal microscopy, atomic force microscopy (using immunolabeled cells with gold nanoparticles) and scanning electron microscopy, all corroborate this hypothesis. The effect of ammonia on AQP4 seems not to be due to any osmotic effect; identical osmotic stress induced by glutamine and salt had no significant effect on the AQP4 content. AQP4 functional analysis (subjecting astrocytes to a hypo-osmotic medium and using flow cytometry to measure cell size) demonstrated a smaller water influx in ammonia-treated astrocytes suggesting that AQP4 aggregates are representative of an inactive status; however, more confirmatory studies are required to fully understand the functional status of AQP4 aggregates. The present results suggest that ammonia affects AQP4 expression and distribution, and that astrocytes change their expression of AQP4 mRNA as well as the aggregation status of the ensuing protein depending on the ammonia concentration and duration of exposure.
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Affiliation(s)
- Guillermo Bodega
- Departamento de Biología Celular y Genética, Facultad de Biología, Universidad de Alcalá, 28871 Alcalá de Henares, Madrid, Spain.
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35
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6-Hydroxydopamine leads to T2 hyperintensity, decreased claudin-3 immunoreactivity and altered aquaporin 4 expression in the striatum. Behav Brain Res 2012; 232:148-58. [DOI: 10.1016/j.bbr.2012.04.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2012] [Revised: 03/30/2012] [Accepted: 04/03/2012] [Indexed: 11/23/2022]
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36
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Pasantes-Morales H, Vázquez-Juárez E. Transporters and channels in cytotoxic astrocyte swelling. Neurochem Res 2012; 37:2379-87. [PMID: 22544664 DOI: 10.1007/s11064-012-0777-2] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2012] [Revised: 03/30/2012] [Accepted: 04/03/2012] [Indexed: 12/29/2022]
Abstract
Brain edema is a severe clinical complication in a number of pathologies and is a major cause of increased morbidity and death. The swelling of astrocytes caused by a disruption of water and ion homeostasis, is the primary event contributing to the cytotoxic form of brain edema. Astrocyte cytotoxic swelling ultimately leads to transcapillary fluxes of ions and water into the brain parenchyma. This review focuses on the implication of transporters and channels in cytotoxic astrocyte swelling in hyponatremia, ischemia, trauma and hepatic encephalopathy. Emphasis is put on some salient features of the astrocyte physiology, all related to cell swelling, i.e. predominance of aquaporins, control of K(+) homeostasis and ammonia accumulation during the brain ammonia-detoxifying process.
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Affiliation(s)
- Herminia Pasantes-Morales
- División de Neurociencias, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Mexico City, Mexico.
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37
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Collins MA, Neafsey EJ. Neuroinflammatory pathways in binge alcohol-induced neuronal degeneration: oxidative stress cascade involving aquaporin, brain edema, and phospholipase A2 activation. Neurotox Res 2011; 21:70-8. [PMID: 21927955 DOI: 10.1007/s12640-011-9276-5] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2011] [Revised: 09/01/2011] [Accepted: 09/05/2011] [Indexed: 12/21/2022]
Abstract
Chronic binge alcohol exposure in adult rat models causes neuronal degeneration in the cortex and hippocampus that is not reduced by excitotoxic receptor antagonists, but is prevented by antioxidants. Neuroinflammatory (glial-neuronal) signaling pathways are believed to underlie the oxidative stress and brain damage. Based on our experimental results as well as increased knowledge about the pro-neuroinflammatory potential of glial water channels, we propose that induction of aquaporin-4 can be a critical initiating factor in alcohol's neurotoxic effects, through the instigation of cellular edema-based neuroinflammatory cascades involving increased phospholipase A2 activities, polyunsaturated fatty acid release/membrane depletion, decreased prosurvival signaling, and oxidative stress. A testable scheme for this pathway is presented that incorporates recent findings in the alcohol-brain literature indicating a role for neuroimmune activation (upregulation of NF-kappaB, proinflammatory cytokines, and toll-like receptors). We present the argument that such neuroimmune activation could be associated with or even dependent on increased aquaporin-4 and glial swelling as well.
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Affiliation(s)
- Michael A Collins
- Department of Molecular Pharmacology & Therapeutics, Stritch School of Medicine, Loyola University Chicago, 2160 South First Avenue, Maywood, IL 60153, USA.
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38
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Pisani F, Rossi A, Nicchia GP, Svelto M, Frigeri A. Translational regulation mechanisms of aquaporin-4 supramolecular organization in astrocytes. Glia 2011; 59:1923-32. [PMID: 21850708 DOI: 10.1002/glia.21234] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2011] [Accepted: 07/27/2011] [Indexed: 12/21/2022]
Abstract
The two predominant isoforms of Aquaporin-4 (AQP4), AQP4-M23 and AQP4-M1, assemble in the plasma membrane to form supramolecular structures called Orthogonal Array of Particles (OAPs) whose dimension is tightly associated to the M1/M23 ratio. Here, we explore translational regulation contribution to M1/M23 expression in primary cultures of rat astrocytes, and analyze the role of M1 mRNA 5'untranslated region (5'UTR) in this mechanism. Using isoform-specific RNAi we found that in rat astrocytes primary cultures a large proportion of M23 protein derives from M1 mRNA translation. Furthermore, site-specific mutagenesis of the 5'UTR sequence of AQP4-M1 mRNA indicates that a multiple-site leaky scanning mechanism, an out-of-frame upstream ORF (uORF), and a reinitiation mechanism are able to modulate the M1/M23 ratio and consequently, OAPs formation. These mechanisms are likely to be shared by different species, including human, and they can also be assumed to play a role in those pathophysiological situations where the organization of AQP4 in supramolecular structures (OAPs) is involved. Finally, we report that, when transfected in Hela cells, the longer rat AQP4 isoform, called Mz, which is not present in human impairs OAPs formation.
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Affiliation(s)
- Francesco Pisani
- Department of General and Environmental Physiology and Centre of Excellence in Comparative Genomics (CEGBA), University of Bari, Bari, Italy
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39
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Bonomini F, Francesca B, Rezzani R. Aquaporin and blood brain barrier. Curr Neuropharmacol 2011; 8:92-6. [PMID: 21119879 PMCID: PMC2923372 DOI: 10.2174/157015910791233132] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2009] [Revised: 03/01/2010] [Accepted: 04/07/2010] [Indexed: 12/25/2022] Open
Abstract
Large water fluxes continuously take place between the different compartments of the brain as well as between the brain parenchyma and the blood or cerebrospinal fluid. Disturbances in this well-regulated water homeostasis may have deleterious effects on brain function and may be fatal in cases where water accumulates in the brain following pathologies such as ischemia, haemorrhage, or brain trauma. The molecular pathways by which water molecules cross the blood brain barrier are not well-understood, although the discovery of Aquaporin 4 (AQP4) in the brain improved the understanding of some of these transport processes, particularly under pathological conditions.
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Affiliation(s)
- Francesca Bonomini
- Division of Human Anatomy, Department of Biomedical Sciences and Biotechnologies, University of Brescia, V.le Europa 11, 25123 Brescia, Italy
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40
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Jhala SS, Hazell AS. Modeling neurodegenerative disease pathophysiology in thiamine deficiency: Consequences of impaired oxidative metabolism. Neurochem Int 2011; 58:248-60. [DOI: 10.1016/j.neuint.2010.11.019] [Citation(s) in RCA: 73] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2010] [Revised: 11/18/2010] [Accepted: 11/25/2010] [Indexed: 11/28/2022]
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41
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Rao KVR, Jayakumar AR, Reddy PVB, Tong X, Curtis KM, Norenberg MD. Aquaporin-4 in manganese-treated cultured astrocytes. Glia 2010; 58:1490-9. [PMID: 20648640 DOI: 10.1002/glia.21023] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Manganese in excess is neurotoxic and causes CNS injury resembling that of Parkinson's disease. In brain, astrocytes predominantly take up and accumulate manganese and are thus vulnerable to its toxicity. Manganese was shown to induce cell swelling in cultured astrocytes, and oxidative/nitrosative stress (ONS) mediates such swelling. As aquaporin-4 (AQP4) is important in the mechanism of astrocyte swelling, we examined the effect of manganese on AQP4 protein levels in cultured astrocytes. Treatment of cultures with manganese increased AQP4 protein in the plasma membrane (PM), whereas total cellular AQP4 protein and mRNA levels were unchanged, suggesting that increased AQP4 levels is due to its increased stability and/or increased trafficking to the PM and not to its neosynthesis. AQP4 gene silencing by small interfering ribonucleic acid resulted in a marked reduction in astrocyte swelling by manganese. Antioxidants, as well as an inhibitor of nitric oxide synthase, diminished the increase in AQP4 protein expression, suggesting a role of ONS in the mechanism of AQP4 increase. As ONS is known to activate mitogen-activated protein kinases (MAPKs) and MAPK activation has been implicated in astrocyte swelling, we examined the effect of manganese on the activation of MAPKs and found an increased phosphorylation of extracellular signal-regulated kinase (ERK)1/2, C-Jun amino-terminal kinase (JNK)1/2/3, and p38-MAPK. Inhibitors of ERK1/2 and p38-MAPK (but not of JNK) blocked (40-60%) the manganese-induced increase in AQP4 protein content and astrocyte swelling, suggesting the involvement of these kinases in the increased AQP4 content. Inhibition of oxidative stress or MAPKs may represent potential strategies for counteracting AQP4-related neurological complications associated with manganese toxicity.
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Affiliation(s)
- Kakulavarapu V Rama Rao
- Department of Pathology, University of Miami Miller School of Medicine, Miami, FL 33101, USA.
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42
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Zelenina M. Regulation of brain aquaporins. Neurochem Int 2010; 57:468-88. [DOI: 10.1016/j.neuint.2010.03.022] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2009] [Revised: 03/21/2010] [Accepted: 03/31/2010] [Indexed: 01/27/2023]
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43
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Abstract
Intracranial hypertension caused by brain edema and associated astrocyte swelling is a potentially lethal complication of acute liver failure (ALF). Mechanisms of edema formation are not well understood, but elevated levels of blood and brain ammonia and its by-product glutamine have been implicated in this process. Since aquaporin-4 (AQP4) has been implicated in brain edema in other conditions, we examined its role in a rat model of ALF induced by the hepatotoxin thioacetamide. Rats with ALF showed increased AQP4 protein in the plasma membrane (PM). Total tissue levels of AQP4 protein and mRNA levels were not altered, indicating that increased AQP4 is not transcriptionally mediated but likely reflects a more stable anchoring of AQP4 to the PM and/or interference with its degradation. An increase inAQP4 immunoreactivity in thePM was observed in perivascular astrocytes in ALF. Rats with ALF also showed increased levels of α-syntrophin, a protein involved in anchoringAQP4 to perivascular astrocytic end-feet. Increased AQP4 andα-syntrophin levels were inhibited by L-histidine, an inhibitor of glutamine transport into mitochondria, suggesting a role for glutamine in the increase of PM levels of AQP4. These results indicate that increased AQP4 PM levels in perivascular astrocytic end-feet are likely critical to the development of brain edema in ALF.
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44
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Brain volume regulation: osmolytes and aquaporin perspectives. Neuroscience 2010; 168:871-84. [DOI: 10.1016/j.neuroscience.2009.11.074] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2009] [Revised: 11/13/2009] [Accepted: 11/25/2009] [Indexed: 02/08/2023]
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Tran ND, Kim S, Vincent HK, Rodriguez A, Hinton DR, Bullock MR, Young HF. Aquaporin-1-mediated cerebral edema following traumatic brain injury: effects of acidosis and corticosteroid administration. J Neurosurg 2010; 112:1095-104. [PMID: 19731985 DOI: 10.3171/2009.8.jns081704] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
OBJECT Dysregulation of water homeostasis induces cerebral edema. Edema is a major cause of morbidity and mortality following traumatic brain injury (TBI). Aquaporin-1 (AQP-1), a water channel found in the brain, can function as a transporter for CO2 across the cellular membrane. Additionally, AQP-1's promoter contains a glucocorticoid response element. Thus, AQP-1 may be involved with edema-related brain injury and might be modulated by external conditions such as the pH and the presence of steroids. In this study, the authors investigated the hypotheses that: 1) AQP-1 participates in brain water homeostasis following TBI; 2) secondary injury (for example, acidosis) alters the expression of AQP-1 and exacerbates cerebral edema; and 3) corticosteroids augment brain AQP-1 expression and differentially affect cerebral edema under nonacidotic and acidotic conditions. METHODS Anesthetized Sprague-Dawley rats were subjected to moderate to severe TBI (2.5-3.5 atm) or surgery without injury, and they were randomized to receive a 3-mg/kg bolus of intravenous dexamethasone within 10 minutes after injury or surgery, a 3-mg/kg bolus of dexamethasone followed by 1-mg/kg maintenance doses every 8 hours for 24 hours, or saline boluses at similar time intervals. A second group of animals was subjected to respiratory acidosis with target arterial blood pH 6.8-7.2 for 1 hour following the surgery or injury. To evaluate selective blockage of AQP-1, some animals received a single intraperitoneal dose of HgCl2 (0.3-30.0 mmol/L) within 30 minutes of injury or surgery. At 4 or 24 hours postinjury, animals were killed and their brains were harvested for mRNA, protein, or water content analyses. RESULTS The authors demonstrated elevated cerebral edema levels at 4 and 24 hours following TBI. Dexamethasone administration within 1 hour of TBI attenuated the cerebral edema under nonacidotic conditions but worsened it under acidotic conditions. Selective blockage of AQP-1 channels with HgCl2 attenuated the edematous effects of corticosteroids and acidosis. Reverse transcriptase polymerase chain reaction and immunohistochemical analyses demonstrated a paucity of AQP-1 in the cerebral cortices of the uninjured animals. In contrast, AQP-1 mRNA and protein levels were higher in the cerebral cortices of animals that sustained a TBI. CONCLUSIONS These findings implicate an important, modifiable role for AQP-1 in water homeostasis within the CNS following TBI.
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Affiliation(s)
- Nam D Tran
- Department of Neurosurgery, Medical College of Virginia, Virginia Commonwealth University, Richmond, Virginia, USA.
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46
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Abstract
It is well established that lactate can be used as an energy substrate by the brain by conversion to pyruvate and a subsequent oxidation in the mitochondria. Knowing the need for readily metabolizable substrates directly after ischemia and the protective effect of lactate after excitotoxicity, the aim of this study was to investigate whether lactate administration directly after ischemia could be neuroprotective. In vitro, the addition of 4 mmol/L L-lactate to the medium of rat organotypic hippocampal slices, directly after oxygen and glucose deprivation (OGD), protected against neuronal death, whereas a higher dose of 20 mmol/L was toxic. In vivo, after middle cerebral artery occlusion in the mouse, an intracerebroventricular injection of 2 microL of 100 mmol/L L-lactate, immediately after reperfusion, led to a significant decrease in lesion size, which was more pronounced in the striatum, and an improvement in neurologic outcome. A later injection 1 h after reperfusion did not reduce lesion size, but significantly improved neurologic outcome, which is an important point in the context of a potential clinical application. Therefore, a moderate increase in lactate after ischemia may be a therapeutic tool.
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Hazell AS. Astrocytes are a major target in thiamine deficiency and Wernicke's encephalopathy. Neurochem Int 2009; 55:129-35. [PMID: 19428817 DOI: 10.1016/j.neuint.2009.02.020] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2008] [Revised: 02/25/2009] [Accepted: 02/27/2009] [Indexed: 10/21/2022]
Abstract
Thiamine deficiency (TD) is the underlying cause, and an established model, of Wernicke's encephalopathy (WE). Although the neurologic dysfunction and brain damage that results from TD has been well-described, the precise mechanisms that lead to the selective histological lesions characteristic of this disorder remain a mystery. Over the course of many years, various processes have been proposed that could lead to focal neuronal cell death in this disorder. But despite a concerted effort to relate these processes to a clear sequelae of events culminating in development of the focal neuropathology, little success has resulted. In recent years, however, a role for astrocytes in the pathophysiology of TD has been emerging. Here, alterations in glutamate uptake, and levels of the astrocytic glutamate transporters EAAT1 and EAAT2 in TD and WE, are discussed in terms of an excitotoxic event, along with the GABA transporter subtype GAT-3, and changes in other astrocytic proteins including GFAP and glutamine synthetase. Lactic acidosis, changes in the water channel protein AQP-4 and brain edema are also a focus of attention in relation to astrocyte dysfunction, while involvement of oxidative stress and inflammatory processes, along with white matter injury in terms of excitotoxicity are other key issues considered. In summary, a new appraisal of the extent of involvement of astrocytes in TD and WE is presented, with the evidence suggesting these cells represent a major target for damage during the disease process.
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Affiliation(s)
- Alan S Hazell
- Department of Medicine, University of Montreal, Montreal, Quebec, Canada.
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Hazell AS, Butterworth RF. Update of Cell Damage Mechanisms in Thiamine Deficiency: Focus on Oxidative Stress, Excitotoxicity and Inflammation. Alcohol Alcohol 2009; 44:141-7. [DOI: 10.1093/alcalc/agn120] [Citation(s) in RCA: 114] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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