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Mills WA, Woo AM, Jiang S, Martin J, Surendran D, Bergstresser M, Kimbrough IF, Eyo UB, Sofroniew MV, Sontheimer H. Astrocyte plasticity in mice ensures continued endfoot coverage of cerebral blood vessels following injury and declines with age. Nat Commun 2022; 13:1794. [PMID: 35379828 PMCID: PMC8980042 DOI: 10.1038/s41467-022-29475-2] [Citation(s) in RCA: 26] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2021] [Accepted: 03/11/2022] [Indexed: 01/30/2023] Open
Abstract
Astrocytes extend endfeet that enwrap the vasculature, and disruptions to this association which may occur in disease coincide with breaches in blood-brain barrier (BBB) integrity. Here we investigate if focal ablation of astrocytes is sufficient to disrupt the BBB in mice. Targeted two-photon chemical apoptotic ablation of astrocytes induced a plasticity response whereby surrounding astrocytes extended processes to cover vascular vacancies. In young animals, replacement processes occur in advance of endfoot retraction, but this is delayed in aged animals. Stimulation of replacement astrocytes results in constriction of pre-capillary arterioles, suggesting that replacement astrocytes are functional. Pharmacological inhibition of pSTAT3, as well as astrocyte specific deletion of pSTAT3, reduces astrocyte replacement post-ablation, without perturbations to BBB integrity. Similar endfoot replacement occurs following astrocyte cell death due to reperfusion in a stroke model. Together, these studies uncover the ability of astrocytes to maintain cerebrovascular coverage via substitution from nearby cells.
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Affiliation(s)
- William A. Mills
- grid.27755.320000 0000 9136 933XBrain, Immunology, and Glia Center, University of Virginia School of Medicine, Charlottesville, VA USA ,grid.27755.320000 0000 9136 933XDepartment of Neuroscience, University of Virginia School of Medicine, Charlottesville, VA USA ,grid.27755.320000 0000 9136 933XRobert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, VA USA ,grid.438526.e0000 0001 0694 4940Graduate Program in Translational Biology, Medicine, & Health, Virginia Polytechnic Institute and State University, Blacksburg, VA USA
| | - AnnaLin M. Woo
- grid.27755.320000 0000 9136 933XBrain, Immunology, and Glia Center, University of Virginia School of Medicine, Charlottesville, VA USA ,grid.27755.320000 0000 9136 933XDepartment of Neuroscience, University of Virginia School of Medicine, Charlottesville, VA USA
| | - Shan Jiang
- grid.168010.e0000000419368956Department of Material Science and Engineering, Stanford University, Stanford, CA USA ,grid.168010.e0000000419368956Wu Tsai Neurosciences Institute, Stanford University, Stanford, CA USA
| | - Joelle Martin
- grid.438526.e0000 0001 0694 4940Graduate Program in Translational Biology, Medicine, & Health, Virginia Polytechnic Institute and State University, Blacksburg, VA USA
| | - Dayana Surendran
- grid.27755.320000 0000 9136 933XBrain, Immunology, and Glia Center, University of Virginia School of Medicine, Charlottesville, VA USA ,grid.27755.320000 0000 9136 933XDepartment of Neuroscience, University of Virginia School of Medicine, Charlottesville, VA USA
| | - Matthew Bergstresser
- grid.438526.e0000 0001 0694 4940School of Neuroscience, Virginia Polytechnic Institute and State University, Blacksburg, VA USA
| | - Ian F. Kimbrough
- grid.27755.320000 0000 9136 933XBrain, Immunology, and Glia Center, University of Virginia School of Medicine, Charlottesville, VA USA ,grid.27755.320000 0000 9136 933XDepartment of Neuroscience, University of Virginia School of Medicine, Charlottesville, VA USA
| | - Ukpong B. Eyo
- grid.27755.320000 0000 9136 933XBrain, Immunology, and Glia Center, University of Virginia School of Medicine, Charlottesville, VA USA ,grid.27755.320000 0000 9136 933XDepartment of Neuroscience, University of Virginia School of Medicine, Charlottesville, VA USA ,grid.27755.320000 0000 9136 933XRobert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, VA USA
| | - Michael V. Sofroniew
- grid.19006.3e0000 0000 9632 6718Department of Neurobiology, University of California, Los Angeles, CA USA
| | - Harald Sontheimer
- grid.27755.320000 0000 9136 933XBrain, Immunology, and Glia Center, University of Virginia School of Medicine, Charlottesville, VA USA ,grid.27755.320000 0000 9136 933XDepartment of Neuroscience, University of Virginia School of Medicine, Charlottesville, VA USA
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152
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Woo E, Datta D, Arnsten AFT. Glutamate Metabotropic Receptor Type 3 (mGlu3) Localization in the Rat Prelimbic Medial Prefrontal Cortex. Front Neuroanat 2022; 16:849937. [PMID: 35444520 PMCID: PMC9013768 DOI: 10.3389/fnana.2022.849937] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2022] [Accepted: 02/18/2022] [Indexed: 11/13/2022] Open
Abstract
Metabotropic glutamate receptors type 3 (mGlu3, encoded by GRM3) are increasingly related to cognitive functioning, including the working memory operations of the prefrontal cortex (PFC). In rhesus monkeys, mGlu3 are most commonly expressed on glia (36%), but are also very prominent on layer III dendritic spines (23%) in the dorsolateral PFC (dlPFC) where they enhance working memory-related neuronal firing. In contrast, mGlu2 are predominately presynaptic in layer III of macaque dlPFC, indicating a pre- vs. post-synaptic dissociation by receptor subtype. The current study examined the cellular and subcellular localizations of mGlu3 in the rat prelimbic medial PFC (PL mPFC), a region needed for spatial working memory performance in rodents. Multiple label immunofluorescence demonstrated mGlu3 expression in neurons and astrocytes, with rare labeling in microglia. Immunoelectron microscopy of layers III and V found that the predominant location for mGlu3 was on axons (layer III: 35.9%; layer V: 44.1%), with labeling especially prominent within the intervaricose segments distant from axon terminals. mGlu3 were also found on glia (likely astrocytes), throughout the glial membrane (layer III: 28.2%; layer V: 29.5%). Importantly, mGlu3 could be seen on dendritic spines, especially in layer III (layer III: 15.6%; layer V: 8.2%), with minor labeling on dendrites. These data show that there are some similarities between mGlu3 expression in rat PL mPFC and macaque dlPFC, but the spine expression enriches and differentiates in the more recently evolved primate dlPFC.
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153
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Tran CHT. Toolbox for studying neurovascular coupling in vivo, with a focus on vascular activity and calcium dynamics in astrocytes. NEUROPHOTONICS 2022; 9:021909. [PMID: 35295714 PMCID: PMC8920490 DOI: 10.1117/1.nph.9.2.021909] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2021] [Accepted: 02/23/2022] [Indexed: 05/14/2023]
Abstract
Significance: Insights into the cellular activity of each member of the neurovascular unit (NVU) is critical for understanding their contributions to neurovascular coupling (NVC)-one of the key control mechanisms in cerebral blood flow regulation. Advances in imaging and genetic tools have enhanced our ability to observe, manipulate and understand the cellular activity of NVU components, namely neurons, astrocytes, microglia, endothelial cells, vascular smooth muscle cells, and pericytes. However, there are still many unresolved questions. Since astrocytes are considered electrically unexcitable,Ca 2 + signaling is the main parameter used to monitor their activity. It is therefore imperative to study astrocyticCa 2 + dynamics simultaneously with vascular activity using tools appropriate for the question of interest. Aim: To highlight currently available genetic and imaging tools for studying the NVU-and thus NVC-with a focus on astrocyteCa 2 + dynamics and vascular activity, and discuss the utility, technical advantages, and limitations of these tools for elucidating NVC mechanisms. Approach: We draw attention to some outstanding questions regarding the mechanistic basis of NVC and emphasize the role of astrocyticCa 2 + elevations in functional hyperemia. We further discuss commonly used genetic, and optical imaging tools, as well as some newly developed imaging modalities for studying NVC at the cellular level, highlighting their advantages and limitations. Results: We provide an overview of the current state of NVC research, focusing on the role of astrocyticCa 2 + elevations in functional hyperemia; summarize recent advances in genetically engineeredCa 2 + indicators, fluorescence microscopy techniques for studying NVC; and discuss the unmet challenges for future imaging development. Conclusions: Advances in imaging techniques together with improvements in genetic tools have significantly contributed to our understanding of NVC. Many pieces of the puzzle have been revealed, but many more remain to be discovered. Ultimately, optimizing NVC research will require a concerted effort to improve imaging techniques, available genetic tools, and analytical software.
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Affiliation(s)
- Cam Ha T. Tran
- University of Nevada, Reno School of Medicine, Department of Physiology and Cell Biology, Reno, Nevada, United States
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154
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Abstract
The brain harbors a unique ability to, figuratively speaking, shift its gears. During wakefulness, the brain is geared fully toward processing information and behaving, while homeostatic functions predominate during sleep. The blood-brain barrier establishes a stable environment that is optimal for neuronal function, yet the barrier imposes a physiological problem; transcapillary filtration that forms extracellular fluid in other organs is reduced to a minimum in brain. Consequently, the brain depends on a special fluid [the cerebrospinal fluid (CSF)] that is flushed into brain along the unique perivascular spaces created by astrocytic vascular endfeet. We describe this pathway, coined the term glymphatic system, based on its dependency on astrocytic vascular endfeet and their adluminal expression of aquaporin-4 water channels facing toward CSF-filled perivascular spaces. Glymphatic clearance of potentially harmful metabolic or protein waste products, such as amyloid-β, is primarily active during sleep, when its physiological drivers, the cardiac cycle, respiration, and slow vasomotion, together efficiently propel CSF inflow along periarterial spaces. The brain's extracellular space contains an abundance of proteoglycans and hyaluronan, which provide a low-resistance hydraulic conduit that rapidly can expand and shrink during the sleep-wake cycle. We describe this unique fluid system of the brain, which meets the brain's requisites to maintain homeostasis similar to peripheral organs, considering the blood-brain-barrier and the paths for formation and egress of the CSF.
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Affiliation(s)
- Martin Kaag Rasmussen
- Center for Translational Neuromedicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Humberto Mestre
- Center for Translational Neuromedicine, University of Rochester Medical Center, Rochester, New York
| | - Maiken Nedergaard
- Center for Translational Neuromedicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
- Center for Translational Neuromedicine, University of Rochester Medical Center, Rochester, New York
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155
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Fang Y, Huang L, Wang X, Si X, Lenahan C, Shi H, Shao A, Tang J, Chen S, Zhang J, Zhang JH. A new perspective on cerebrospinal fluid dynamics after subarachnoid hemorrhage: From normal physiology to pathophysiological changes. J Cereb Blood Flow Metab 2022; 42:543-558. [PMID: 34806932 PMCID: PMC9051143 DOI: 10.1177/0271678x211045748] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/24/2021] [Revised: 08/14/2021] [Accepted: 08/19/2021] [Indexed: 11/17/2022]
Abstract
Knowledge about the dynamic metabolism and function of cerebrospinal fluid (CSF) physiology has rapidly progressed in recent decades. It has traditionally been suggested that CSF is produced by the choroid plexus and drains to the arachnoid villi. However, recent findings have revealed that the brain parenchyma produces a large portion of CSF and drains through the perivascular glymphatic system and meningeal lymphatic vessels into the blood. The primary function of CSF is not limited to maintaining physiological CNS homeostasis but also participates in clearing waste products resulting from neurodegenerative diseases and acute brain injury. Aneurysmal subarachnoid hemorrhage (SAH), a disastrous subtype of acute brain injury, is associated with high mortality and morbidity. Post-SAH complications contribute to the poor outcomes associated with SAH. Recently, abnormal CSF flow was suggested to play an essential role in the post-SAH pathophysiological changes, such as increased intracerebral pressure, brain edema formation, hydrocephalus, and delayed blood clearance. An in-depth understanding of CSF dynamics in post-SAH events would shed light on potential development of SAH treatment options. This review summarizes and updates the latest physiological characteristics of CSF dynamics and discusses potential pathophysiological changes and therapeutic targets after SAH.
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Affiliation(s)
- Yuanjian Fang
- Department of Neurosurgery, The Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, China
| | - Lei Huang
- Department of Neurosurgery, Loma Linda University, Loma Linda, CA, USA
- Department of Physiology and Pharmacology, Loma Linda University, Loma Linda, CA, USA
| | - Xiaoyu Wang
- Department of Neurosurgery, The Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, China
| | - Xiaoli Si
- Department of Neurology, The Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, China
| | - Cameron Lenahan
- Department of Neurosurgery, Loma Linda University, Loma Linda, CA, USA
- Burrell College of Osteopathic Medicine, Las Cruces, NM, USA
| | - Hui Shi
- Department of Neurosurgery, Loma Linda University, Loma Linda, CA, USA
- Department of Neurosurgery, Yongchuan Hospital, Chongqing Medical University, Chongqing, China
| | - Anwen Shao
- Department of Neurosurgery, The Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, China
| | - Jiping Tang
- Department of Neurosurgery, Loma Linda University, Loma Linda, CA, USA
- Department of Physiology and Pharmacology, Loma Linda University, Loma Linda, CA, USA
- Department of Anesthesiology, Loma Linda University, Loma Linda, CA, USA
| | - Sheng Chen
- Department of Neurosurgery, The Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, China
| | - Jianmin Zhang
- Department of Neurosurgery, The Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, China
| | - John H Zhang
- Department of Neurosurgery, Loma Linda University, Loma Linda, CA, USA
- Department of Physiology and Pharmacology, Loma Linda University, Loma Linda, CA, USA
- Department of Anesthesiology, Loma Linda University, Loma Linda, CA, USA
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156
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Gorzo KA, Gordon GR. Photonics tools begin to clarify astrocyte calcium transients. NEUROPHOTONICS 2022; 9:021907. [PMID: 35211642 PMCID: PMC8857908 DOI: 10.1117/1.nph.9.2.021907] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Accepted: 02/01/2022] [Indexed: 05/27/2023]
Abstract
Astrocytes integrate information from neurons and the microvasculature to coordinate brain activity and metabolism. Using a variety of calcium-dependent cellular mechanisms, these cells impact numerous aspects of neurophysiology in health and disease. Astrocyte calcium signaling is highly diverse, with complex spatiotemporal features. Here, we review astrocyte calcium dynamics and the optical imaging tools used to measure and analyze these events. We briefly cover historical calcium measurements, followed by our current understanding of how calcium transients relate to the structure of astrocytes. We then explore newer photonics tools including super-resolution techniques and genetically encoded calcium indicators targeted to specific cellular compartments and how these have been applied to astrocyte biology. Finally, we provide a brief overview of analysis software used to accurately quantify the data and ultimately aid in our interpretation of the various functions of astrocyte calcium transients.
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Affiliation(s)
- Kelsea A. Gorzo
- University of Calgary, Hotchkiss Brain Institute, Cumming School of Medicine, Calgary, Alberta, Canada
| | - Grant R. Gordon
- University of Calgary, Hotchkiss Brain Institute, Cumming School of Medicine, Calgary, Alberta, Canada
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157
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Brain Metabolic Alterations in Alzheimer's Disease. Int J Mol Sci 2022; 23:ijms23073785. [PMID: 35409145 PMCID: PMC8998942 DOI: 10.3390/ijms23073785] [Citation(s) in RCA: 31] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2022] [Revised: 03/23/2022] [Accepted: 03/28/2022] [Indexed: 01/27/2023] Open
Abstract
The brain is one of the most energy-consuming organs in the body. Satisfying such energy demand requires compartmentalized, cell-specific metabolic processes, known to be complementary and intimately coupled. Thus, the brain relies on thoroughly orchestrated energy-obtaining agents, processes and molecular features, such as the neurovascular unit, the astrocyte-neuron metabolic coupling, and the cellular distribution of energy substrate transporters. Importantly, early features of the aging process are determined by the progressive perturbation of certain processes responsible for adequate brain energy supply, resulting in brain hypometabolism. These age-related brain energy alterations are further worsened during the prodromal stages of neurodegenerative diseases, namely Alzheimer's disease (AD), preceding the onset of clinical symptoms, and are anatomically and functionally associated with the loss of cognitive abilities. Here, we focus on concrete neuroenergetic features such as the brain's fueling by glucose and lactate, the transporters and vascular system guaranteeing its supply, and the metabolic interactions between astrocytes and neurons, and on its neurodegenerative-related disruption. We sought to review the principles underlying the metabolic dimension of healthy and AD brains, and suggest that the integration of these concepts in the preventive, diagnostic and treatment strategies for AD is key to improving the precision of these interventions.
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158
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Autoimmune Encephalitis in COVID-19 Infection: Our Experience and Systematic Review of the Literature. Biomedicines 2022; 10:biomedicines10040774. [PMID: 35453524 PMCID: PMC9024859 DOI: 10.3390/biomedicines10040774] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2022] [Revised: 03/02/2022] [Accepted: 03/21/2022] [Indexed: 01/08/2023] Open
Abstract
The neurologic complications of COVID-19 infection are frequent in hospitalized patients; a high percentage of them present neurologic manifestations at some point during the course of their disease. Headache, muscle pain, encephalopathy and dizziness are among the most common complications. Encephalitis is an inflammatory condition with many etiologies. There are several forms of encephalitis associated with antibodies against intracellular neuronal proteins, cell surfaces or synaptic proteins, referred to as autoimmune encephalitis. Several case reports published in the literature document autoimmune encephalitis cases triggered by COVID-19 infection. Our paper first presents our experience in this issue and then systematically reviews the literature on autoimmune encephalitis that developed in the background of SARS-CoV-2 infections and also discusses the possible pathophysiological mechanisms of auto-immune-mediated damage to the nervous system. This review contributes to improve the management and prognosis of COVID-19-related autoimmune encephalitis.
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159
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Kim HK, Song J. Hypothyroidism and Diabetes-Related Dementia: Focused on Neuronal Dysfunction, Insulin Resistance, and Dyslipidemia. Int J Mol Sci 2022; 23:ijms23062982. [PMID: 35328405 PMCID: PMC8952212 DOI: 10.3390/ijms23062982] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2022] [Revised: 03/06/2022] [Accepted: 03/07/2022] [Indexed: 01/27/2023] Open
Abstract
The incidence of dementia is steadily increasing worldwide. The risk factors for dementia are diverse, and include genetic background, environmental factors, sex differences, and vascular abnormalities. Among the subtypes of dementia, diabetes-related dementia is emerging as a complex type of dementia related to metabolic imbalance, due to the increase in the number of patients with metabolic syndrome and dementia worldwide. Thyroid hormones are considered metabolic regulatory hormones and affect various diseases, such as liver failure, obesity, and dementia. Thyroid dysregulation affects various cellular mechanisms and is linked to multiple disease pathologies. In particular, hypothyroidism is considered a critical cause for various neurological problems-such as metabolic disease, depressive symptoms, and dementia-in the central nervous system. Recent studies have demonstrated the relationship between hypothyroidism and brain insulin resistance and dyslipidemia, leading to diabetes-related dementia. Therefore, we reviewed the relationship between hypothyroidism and diabetes-related dementia, with a focus on major features of diabetes-related dementia such as insulin resistance, neuronal dysfunction, and dyslipidemia.
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Affiliation(s)
- Hee Kyung Kim
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Chonnam National University Medical School, 264 Seoyangro, Hwasun 58128, Korea;
| | - Juhyun Song
- Department of Anatomy, Chonnam National University Medical School, Hwasun 58128, Korea
- BioMedical Sciences Graduate Program (BMSGP), Chonnam National University, 264 Seoyangro, Hwasun 58128, Korea
- Correspondence: ; Tel.: +82-61-379-2706; Fax: +82-61-375-5834
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160
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Jackson JG, Krizman E, Takano H, Lee M, Choi GH, Putt ME, Robinson MB. Activation of Glutamate Transport Increases Arteriole Diameter in v ivo: Implications for Neurovascular Coupling. Front Cell Neurosci 2022; 16:831061. [PMID: 35308116 PMCID: PMC8930833 DOI: 10.3389/fncel.2022.831061] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2021] [Accepted: 01/24/2022] [Indexed: 11/21/2022] Open
Abstract
In order to meet the energetic demands of cell-to-cell signaling, increases in local neuronal signaling are matched by a coordinated increase in local blood flow, termed neurovascular coupling. Multiple different signals from neurons, astrocytes, and pericytes contribute to this control of blood flow. Previously, several groups demonstrated that inhibition/ablation of glutamate transporters attenuates the neurovascular response. However, it was not determined if glutamate transporter activation was sufficient to increase blood flow. Here, we used multiphoton imaging to monitor the diameter of fluorescently labeled cortical arterioles in anesthetized C57/B6J mice. We delivered vehicle, glutamate transporter substrates, or a combination of a glutamate transporter substrate with various pharmacologic agents via a glass micropipette while simultaneously visualizing changes in arteriole diameter. We developed a novel image analysis method to automate the measurement of arteriole diameter in these time-lapse analyses. Using this workflow, we first conducted pilot experiments in which we focally applied L-glutamate, D-aspartate, or L-threo-hydroxyaspartate (L-THA) and measured arteriole responses as proof of concept. We subsequently applied the selective glutamate transport substrate L-THA (applied at concentrations that do not activate glutamate receptors). We found that L-THA evoked a significantly larger dilation than that observed with focal saline application. This response was blocked by co-application of the potent glutamate transport inhibitor, L-(2S,3S)-3-[3-[4-(trifluoromethyl)-benzoylamino]benzyloxy]-aspartate (TFB-TBOA). Conversely, we were unable to demonstrate a reduction of this effect through co-application of a cocktail of glutamate and GABA receptor antagonists. These studies provide the first direct evidence that activation of glutamate transport is sufficient to increase arteriole diameter. We explored potential downstream mechanisms mediating this transporter-mediated dilation by using a Ca2+ chelator or inhibitors of reversed-mode Na+/Ca2+ exchange, nitric oxide synthetase, or cyclo-oxygenase. The estimated effects and confidence intervals suggested some form of inhibition for a number of these inhibitors. Limitations to our study design prevented definitive conclusions with respect to these downstream inhibitors; these limitations are discussed along with possible next steps. Understanding the mechanisms that control blood flow are important because changes in blood flow/energy supply are implicated in several neurodegenerative disorders and are used as a surrogate measure of neuronal activity in widely used techniques such as functional magnetic resonance imaging (fMRI).
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Affiliation(s)
- Joshua G. Jackson
- Children’s Hospital of Philadelphia, Philadelphia, PA, United States
- Department of Pediatrics, University of Pennsylvania, Philadelphia, PA, United States
| | - Elizabeth Krizman
- Children’s Hospital of Philadelphia, Philadelphia, PA, United States
- Department of Pediatrics, University of Pennsylvania, Philadelphia, PA, United States
| | - Hajime Takano
- Children’s Hospital of Philadelphia, Philadelphia, PA, United States
- Department of Neurology, University of Pennsylvania, Philadelphia, PA, United States
| | - Meredith Lee
- Children’s Hospital of Philadelphia, Philadelphia, PA, United States
| | - Grace H. Choi
- Department of Biostatistics, Epidemiology & Informatics, University of Pennsylvania, Philadelphia, PA, United States
| | - Mary E. Putt
- Department of Biostatistics, Epidemiology & Informatics, University of Pennsylvania, Philadelphia, PA, United States
| | - Michael B. Robinson
- Children’s Hospital of Philadelphia, Philadelphia, PA, United States
- Department of Systems Pharmacology and Translational Therapeutics, University of Pennsylvania, Philadelphia, PA, United States
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161
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Maheshwari U, Huang SF, Sridhar S, Keller A. The Interplay Between Brain Vascular Calcification and Microglia. Front Aging Neurosci 2022; 14:848495. [PMID: 35309892 PMCID: PMC8924545 DOI: 10.3389/fnagi.2022.848495] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2022] [Accepted: 02/11/2022] [Indexed: 12/17/2022] Open
Abstract
Vascular calcifications are characterized by the ectopic deposition of calcium and phosphate in the vascular lumen or wall. They are a common finding in computed tomography scans or during autopsy and are often directly related to a pathological condition. While the pathogenesis and functional consequences of vascular calcifications have been intensively studied in some peripheral organs, vascular calcification, and its pathogenesis in the central nervous system is poorly characterized and understood. Here, we review the occurrence of vessel calcifications in the brain in the context of aging and various brain diseases. We discuss the pathomechanism of brain vascular calcification in primary familial brain calcification as an example of brain vessel calcification. A particular focus is the response of microglia to the vessel calcification in the brain and their role in the clearance of calcifications.
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Affiliation(s)
- Upasana Maheshwari
- Department of Neurosurgery, Clinical Neuroscience Center, Zürich University Hospital, University of Zürich, Zurich, Switzerland
| | - Sheng-Fu Huang
- Department of Neurosurgery, Clinical Neuroscience Center, Zürich University Hospital, University of Zürich, Zurich, Switzerland
| | - Sucheta Sridhar
- Department of Neurosurgery, Clinical Neuroscience Center, Zürich University Hospital, University of Zürich, Zurich, Switzerland
- Neuroscience Center Zürich, University of Zürich and ETH Zürich, Zurich, Switzerland
| | - Annika Keller
- Department of Neurosurgery, Clinical Neuroscience Center, Zürich University Hospital, University of Zürich, Zurich, Switzerland
- Neuroscience Center Zürich, University of Zürich and ETH Zürich, Zurich, Switzerland
- *Correspondence: Annika Keller,
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162
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Hladky SB, Barrand MA. The glymphatic hypothesis: the theory and the evidence. Fluids Barriers CNS 2022; 19:9. [PMID: 35115036 PMCID: PMC8815211 DOI: 10.1186/s12987-021-00282-z] [Citation(s) in RCA: 87] [Impact Index Per Article: 43.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2021] [Accepted: 10/15/2021] [Indexed: 12/13/2022] Open
Abstract
The glymphatic hypothesis proposes a mechanism for extravascular transport into and out of the brain of hydrophilic solutes unable to cross the blood-brain barrier. It suggests that there is a circulation of fluid carrying solutes inwards via periarterial routes, through the interstitium and outwards via perivenous routes. This review critically analyses the evidence surrounding the mechanisms involved in each of these stages. There is good evidence that both influx and efflux of solutes occur along periarterial routes but no evidence that the principal route of outflow is perivenous. Furthermore, periarterial inflow of fluid is unlikely to be adequate to provide the outflow that would be needed to account for solute efflux. A tenet of the hypothesis is that flow sweeps solutes through the parenchyma. However, the velocity of any possible circulatory flow within the interstitium is too small compared to diffusion to provide effective solute movement. By comparison the earlier classical hypothesis describing extravascular transport proposed fluid entry into the parenchyma across the blood-brain barrier, solute movements within the parenchyma by diffusion, and solute efflux partly by diffusion near brain surfaces and partly carried by flow along "preferred routes" including perivascular spaces, white matter tracts and subependymal spaces. It did not suggest fluid entry via periarterial routes. Evidence is still incomplete concerning the routes and fate of solutes leaving the brain. A large proportion of the solutes eliminated from the parenchyma go to lymph nodes before reaching blood but the proportions delivered directly to lymph or indirectly via CSF which then enters lymph are as yet unclear. In addition, still not understood is why and how the absence of AQP4 which is normally highly expressed on glial endfeet lining periarterial and perivenous routes reduces rates of solute elimination from the parenchyma and of solute delivery to it from remote sites of injection. Neither the glymphatic hypothesis nor the earlier classical hypothesis adequately explain how solutes and fluid move into, through and out of the brain parenchyma. Features of a more complete description are discussed. All aspects of extravascular transport require further study.
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Affiliation(s)
- Stephen B. Hladky
- Department of Pharmacology, University of Cambridge, Cambridge, CB2 1PD UK
| | - Margery A. Barrand
- Department of Pharmacology, University of Cambridge, Cambridge, CB2 1PD UK
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163
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Taliyan R, Kakoty V, Sarathlal KC, Kharavtekar SS, Karennanavar CR, Choudhary YK, Singhvi G, Riadi Y, Dubey SK, Kesharwani P. Nanocarrier mediated drug delivery as an impeccable therapeutic approach against Alzheimer's disease. J Control Release 2022; 343:528-550. [PMID: 35114208 DOI: 10.1016/j.jconrel.2022.01.044] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Revised: 01/22/2022] [Accepted: 01/25/2022] [Indexed: 12/14/2022]
Abstract
For the past several years, dementia, is one of the predominantly observed groups of symptoms in a geriatric population. Alzheimer's disease (AD) is a progressive memory related neurodegenerative disease, for which the current Food and drug administration approved therapeutics are only meant for a symptomatic management rather than targeting the root cause of AD. These therapeutics belong to two classes, Acetylcholine Esterase inhibitors and N-methyl D-aspartate antagonist. Furthermore, to facilitate neuroprotective action in AD, the drugs are majorly expected to reach the specific target area in the brain for the desired efficacy. Thus, there is a huge requirement for drug discovery and development for facilitating the entry of drugs more in brain to exert a specific action. The very first line of defense and the major limitation for the entry of drugs into the brain is the Blood Brain Barrier, followed by Blood-Cerebrospinal Fluid Barrier. More than a barrier, these mainly act as selectively permeable membranes, which allows entry of specific molecules into the brain. Furthermore, specific enzymes result in the degradation of xenobiotics. All these mechanisms pose as hurdles in the way of effective drug delivery in the brain. Thus, novel techniques need to be harbored for the facilitation of the delivery of such drugs into the brain. Nanocarriers are advantageous for facilitating the specific targeted drug treatment in AD. As nanomedicines are one of the novels and most useful approaches for AD, thus the present review mainly focuses on understanding the advanced use of nanocarriers for targeted drug delivery in the management of AD.
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Affiliation(s)
- Rajeev Taliyan
- Neuropsychopharmacology Division, Department of Pharmacy, Birla Institute of Technology and Science-Pilani, Pilani Campus, 333031, Rajasthan, India.
| | - Violina Kakoty
- Neuropsychopharmacology Division, Department of Pharmacy, Birla Institute of Technology and Science-Pilani, Pilani Campus, 333031, Rajasthan, India
| | - K C Sarathlal
- Neuropsychopharmacology Division, Department of Pharmacy, Birla Institute of Technology and Science-Pilani, Pilani Campus, 333031, Rajasthan, India
| | - Sanskruti Santosh Kharavtekar
- Neuropsychopharmacology Division, Department of Pharmacy, Birla Institute of Technology and Science-Pilani, Pilani Campus, 333031, Rajasthan, India
| | - Chandrashekar R Karennanavar
- Neuropsychopharmacology Division, Department of Pharmacy, Birla Institute of Technology and Science-Pilani, Pilani Campus, 333031, Rajasthan, India
| | | | - Gautam Singhvi
- Neuropsychopharmacology Division, Department of Pharmacy, Birla Institute of Technology and Science-Pilani, Pilani Campus, 333031, Rajasthan, India
| | - Yassine Riadi
- Department of Pharmaceutical Chemistry, College of Pharmacy, Prince Sattam Bin Abdulaziz University, Al-Kharj 11942, Saudi Arabia
| | - Sunil Kumar Dubey
- Medical Research, R&D Healthcare Division, Emami Ltd, 13, BT Road, Belgharia, Kolkata 700056, India
| | - Prashant Kesharwani
- Department of Pharmaceutics, School of Pharmaceutical Education and Research, Jamia Hamdard, New Delhi 110062, India.
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164
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Dadgostar E, Rahimi S, Nikmanzar S, Nazemi S, Naderi Taheri M, Alibolandi Z, Aschner M, Mirzaei H, Tamtaji OR. Aquaporin 4 in Traumatic Brain Injury: From Molecular Pathways to Therapeutic Target. Neurochem Res 2022; 47:860-871. [PMID: 35088218 DOI: 10.1007/s11064-021-03512-w] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2021] [Revised: 12/14/2021] [Accepted: 12/16/2021] [Indexed: 12/22/2022]
Abstract
Traumatic brain injury (TBI) is known as an acute degenerative pathology of the central nervous system, and has been shown to increase brain aquaporin 4 (AQP4) expression. Various molecular mechanisms affect AQP4 expression, including neuronal high mobility group box 1, forkhead box O3a, vascular endothelial growth factor, hypoxia-inducible factor-1 α (HIF-1 α) sirtuin 2, NF-κB, Malat1, nerve growth factor and Angiotensin II receptor type 1. In addition, inhibition of AQP4 with FK-506, MK-801 (indirectly by targeting N-methyl-D-aspartate receptor), inactivation of adenosine A2A receptor, levetiracetam, adjudin, progesterone, estrogen, V1aR inhibitor, hypertonic saline, erythropoietin, poloxamer 188, brilliant blue G, HIF-1alpha inhibitor, normobaric oxygen therapy, astaxanthin, epigallocatechin-3-gallate, sesamin, thaliporphine, magnesium, prebiotic fiber, resveratrol and omega-3, as well as AQP4 gene silencing lead to reduced edema upon TBI. This review summarizes current knowledge and evidence on the relationship between AQP4 and TBI, and the potential mechanisms involved.
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Affiliation(s)
- Ehsan Dadgostar
- Behavioral Sciences Research Center, Isfahan University of Medical Sciences, Isfahan, Iran
- Student Research Committee, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Shiva Rahimi
- School of Medicine, Fasa University of Medical Sciences, Fasa, Iran
| | - Shahin Nikmanzar
- Department of Neurosurgery, Iran University of Medical Sciences, Tehran, Iran
| | - Sina Nazemi
- Tracheal Disease Research Center (TDRC), National Research Institute of Tuberculosis and Lung Diseases (NRITLD), Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Mojtaba Naderi Taheri
- Students' Scientific Research Center (SSRC), Tehran University of Medical Sciences, Tehran, Iran
| | - Zahra Alibolandi
- Anatomical Science Research Center, Institute for Basic Sciences, Kashan University of Medical Sciences, Kashan, Iran
| | - Michael Aschner
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
| | - Hamed Mirzaei
- Research Center for Biochemistry and Nutrition in Metabolic Diseases, Institute for Basic Sciences, Kashan University of Medical Sciences, Kashan, Iran.
| | - Omid Reza Tamtaji
- Students' Scientific Research Center (SSRC), Tehran University of Medical Sciences, Tehran, Iran.
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165
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Maurissen TL, Pavlou G, Bichsel C, Villaseñor R, Kamm RD, Ragelle H. Microphysiological Neurovascular Barriers to Model the Inner Retinal Microvasculature. J Pers Med 2022; 12:jpm12020148. [PMID: 35207637 PMCID: PMC8876566 DOI: 10.3390/jpm12020148] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Revised: 01/14/2022] [Accepted: 01/18/2022] [Indexed: 02/07/2023] Open
Abstract
Blood-neural barriers regulate nutrient supply to neuronal tissues and prevent neurotoxicity. In particular, the inner blood-retinal barrier (iBRB) and blood–brain barrier (BBB) share common origins in development, and similar morphology and function in adult tissue, while barrier breakdown and leakage of neurotoxic molecules can be accompanied by neurodegeneration. Therefore, pre-clinical research requires human in vitro models that elucidate pathophysiological mechanisms and support drug discovery, to add to animal in vivo modeling that poorly predict patient responses. Advanced cellular models such as microphysiological systems (MPS) recapitulate tissue organization and function in many organ-specific contexts, providing physiological relevance, potential for customization to different population groups, and scalability for drug screening purposes. While human-based MPS have been developed for tissues such as lung, gut, brain and tumors, few comprehensive models exist for ocular tissues and iBRB modeling. Recent BBB in vitro models using human cells of the neurovascular unit (NVU) showed physiological morphology and permeability values, and reproduced brain neurological disorder phenotypes that could be applicable to modeling the iBRB. Here, we describe similarities between iBRB and BBB properties, compare existing neurovascular barrier models, propose leverage of MPS-based strategies to develop new iBRB models, and explore potentials to personalize cellular inputs and improve pre-clinical testing.
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Affiliation(s)
- Thomas L. Maurissen
- Roche Pharma Research and Early Development, Immunology, Infectious Diseases and Ophthalmology, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd., Grenzacherstrasse 124, 4070 Basel, Switzerland;
| | - Georgios Pavlou
- Department of Biological Engineering, Massachusetts Institute of Technology, 77 Massachusetts Ave., MIT Building, Room NE47-321, Cambridge, MA 02139, USA;
| | - Colette Bichsel
- Roche Pharma Research and Early Development, Pharmaceutical Sciences, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd., Grenzacherstrasse 124, 4070 Basel, Switzerland;
- Roche Pharma Research and Early Development, Institute for Translational Bioengineering, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd., Grenzacherstrasse 124, 4070 Basel, Switzerland
| | - Roberto Villaseñor
- Roche Pharma Research and Early Development, Neuroscience and Rare Diseases, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd., Grenzacherstrasse 124, 4070 Basel, Switzerland;
| | - Roger D. Kamm
- Department of Biological Engineering, Massachusetts Institute of Technology, 77 Massachusetts Ave., MIT Building, Room NE47-321, Cambridge, MA 02139, USA;
- Department of Mechanical Engineering, Massachusetts Institute of Technology, 77 Massachusetts Ave., MIT Building, Room NE47-321, Cambridge, MA 02139, USA
- Correspondence: (R.D.K.); (H.R.)
| | - Héloïse Ragelle
- Roche Pharma Research and Early Development, Immunology, Infectious Diseases and Ophthalmology, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd., Grenzacherstrasse 124, 4070 Basel, Switzerland;
- Correspondence: (R.D.K.); (H.R.)
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166
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Pluta R, Kiś J, Januszewski S, Jabłoński M, Czuczwar SJ. Cross-Talk between Amyloid, Tau Protein and Free Radicals in Post-Ischemic Brain Neurodegeneration in the Form of Alzheimer’s Disease Proteinopathy. Antioxidants (Basel) 2022; 11:antiox11010146. [PMID: 35052650 PMCID: PMC8772936 DOI: 10.3390/antiox11010146] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2021] [Revised: 01/05/2022] [Accepted: 01/09/2022] [Indexed: 02/04/2023] Open
Abstract
Recent years have seen remarkable progress in research into free radicals oxidative stress, particularly in the context of post-ischemic recirculation brain injury. Oxidative stress in post-ischemic tissues violates the integrity of the genome, causing DNA damage, death of neuronal, glial and vascular cells, and impaired neurological outcome after brain ischemia. Indeed, it is now known that DNA damage and repair play a key role in post-stroke white and gray matter remodeling, and restoring the integrity of the blood-brain barrier. This review will present one of the newly characterized mechanisms that emerged with genomic and proteomic development that led to brain ischemia to a new level of post-ischemic neuropathological mechanisms, such as the presence of amyloid plaques and the development of neurofibrillary tangles, which further exacerbate oxidative stress. Finally, we hypothesize that modified amyloid and the tau protein, along with the oxidative stress generated, are new key elements in the vicious circle important in the development of post-ischemic neurodegeneration in a type of Alzheimer’s disease proteinopathy.
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Affiliation(s)
- Ryszard Pluta
- Laboratory of Ischemic and Neurodegenerative Brain Research, Mossakowski Medical Research Institute, Polish Academy of Sciences, Pawińskiego 5 Str., 02-106 Warsaw, Poland;
- Correspondence: ; Tel.: +48-22-608-6540
| | - Jacek Kiś
- Department of Urology, 1st Military Clinical Hospital with the Outpatient Clinic, Al. Racławickie 23, 20-049 Lublin, Poland;
| | - Sławomir Januszewski
- Laboratory of Ischemic and Neurodegenerative Brain Research, Mossakowski Medical Research Institute, Polish Academy of Sciences, Pawińskiego 5 Str., 02-106 Warsaw, Poland;
| | - Mirosław Jabłoński
- Department of Rehabilitation and Orthopedics, Medical University of Lublin, Jaczewskiego 8 Str., 20-090 Lublin, Poland;
| | - Stanisław J. Czuczwar
- Department of Pathophysiology, Medical University of Lublin, Jaczewskiego 8b Str., 20-090 Lublin, Poland;
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167
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Beard E, Lengacher S, Dias S, Magistretti PJ, Finsterwald C. Astrocytes as Key Regulators of Brain Energy Metabolism: New Therapeutic Perspectives. Front Physiol 2022; 12:825816. [PMID: 35087428 PMCID: PMC8787066 DOI: 10.3389/fphys.2021.825816] [Citation(s) in RCA: 69] [Impact Index Per Article: 34.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Accepted: 12/20/2021] [Indexed: 12/11/2022] Open
Abstract
Astrocytes play key roles in the regulation of brain energy metabolism, which has a major impact on brain functions, including memory, neuroprotection, resistance to oxidative stress and homeostatic tone. Energy demands of the brain are very large, as they continuously account for 20–25% of the whole body’s energy consumption. Energy supply of the brain is tightly linked to neuronal activity, providing the origin of the signals detected by the widely used functional brain imaging techniques such as functional magnetic resonance imaging and positron emission tomography. In particular, neuroenergetic coupling is regulated by astrocytes through glutamate uptake that triggers astrocytic aerobic glycolysis and leads to glucose uptake and lactate release, a mechanism known as the Astrocyte Neuron Lactate Shuttle. Other neurotransmitters such as noradrenaline and Vasoactive Intestinal Peptide mobilize glycogen, the reserve for glucose exclusively localized in astrocytes, also resulting in lactate release. Lactate is then transferred to neurons where it is used, after conversion to pyruvate, as a rapid energy substrate, and also as a signal that modulates neuronal excitability, homeostasis, and the expression of survival and plasticity genes. Importantly, glycolysis in astrocytes and more generally cerebral glucose metabolism progressively deteriorate in aging and age-associated neurodegenerative diseases such as Alzheimer’s disease. This decreased glycolysis actually represents a common feature of several neurological pathologies. Here, we review the critical role of astrocytes in the regulation of brain energy metabolism, and how dysregulation of astrocyte-mediated metabolic pathways is involved in brain hypometabolism. Further, we summarize recent efforts at preclinical and clinical stages to target brain hypometabolism for the development of new therapeutic interventions in age-related neurodegenerative diseases.
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168
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Kim SY, Choi J, Roh J, Kim CH. NeuroTrace 500/525 identifies human induced pluripotent stem cell-derived brain pericyte-like cells. Mol Brain 2022; 15:11. [PMID: 35012603 PMCID: PMC8751259 DOI: 10.1186/s13041-021-00893-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2021] [Accepted: 12/25/2021] [Indexed: 01/23/2023] Open
Abstract
In the CNS, pericytes are important for maintaining the blood–brain barrier (BBB) and for controlling blood flow. Recently, several methods were suggested for the differentiation of human pluripotent stem cells (hPSCs) into brain mural cells, specifically pericytes or vascular smooth muscle cells (vSMCs). Unfortunately, identifying the pericytes from among such hPSC-derived mural cells has been challenging. This is due both to the lack of pericyte-specific markers and to the loss of defining anatomical information inherent to culture conditions. We therefore asked whether NeuroTrace 500/525, a newly developed dye that shows cell-specific uptake into pericytes in the mouse brain, can help identify human induced pluripotent stem cell (hiPSC)-derived brain pericyte-like cells. First, we found that NeuroTrace 500/525 specifically stains primary cultured human brain pericytes, confirming its specificity in vitro. Second, we found that NeuroTrace 500/525 specifically labels hiPSC-derived pericyte-like cells, but not endothelial cells or vSMCs derived from the same hiPSCs. Last, we found that neuroectoderm-derived vSMCs, which have pericyte-like features, also take up NeuroTrace 500/525. These data indicate NeuroTrace 500/525 is useful for identifying pericyte-like cells among hiPSC-derived brain mural cells.
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Affiliation(s)
- Seo Young Kim
- Department of Pharmacology, BK21 PLUS Project for Medical Science, Brain Research Institute, Yonsei University College of Medicine, 03722, Seoul, Korea
| | - Jihye Choi
- Department of Pharmacology, BK21 PLUS Project for Medical Science, Brain Research Institute, Yonsei University College of Medicine, 03722, Seoul, Korea
| | - Junhee Roh
- Kyung Hee University College of Medicine, 02447, Seoul, Korea
| | - Chul Hoon Kim
- Department of Pharmacology, BK21 PLUS Project for Medical Science, Brain Research Institute, Yonsei University College of Medicine, 03722, Seoul, Korea.
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169
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Lauranzano E, Rasile M, Matteoli M. Integrating Primary Astrocytes in a Microfluidic Model of the Blood-Brain Barrier. Methods Mol Biol 2022; 2492:225-240. [PMID: 35733047 DOI: 10.1007/978-1-0716-2289-6_12] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
An in vitro blood-brain barrier (BBB) model must be highly reproducible and imitate as much as possible the properties of the in vivo environment, from both the functional and anatomical point of view. In our latest work, a BBB prototype was implemented through the use of human primary brain cells and then integrated in a microfluidic platform (Lauranzano et al., Adv Biosyst 3:e1800335, 2019). Here we describe, step by step, the setting of a customized bio-mimetic platform, which uses human brain endothelial cells and primary astrocytic cells to allow the study of the complex interactions between the immune system and the brain in healthy and neuroinflammatory conditions. The model can be exploited to investigate the neuroimmune communication at the blood-brain interface and to examine the transmigration of patient-derived lymphocytes in order to envisage cutting-edge strategies to restore barrier integrity and block the immune cell influx into the CNS.
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Affiliation(s)
| | - Marco Rasile
- Humanitas Clinical and Research Center, IRCCS, Rozzano, Italy
- Department of Biomedical Sciences, Humanitas University, Pieve Emanuele, Italy
| | - Michela Matteoli
- Humanitas Clinical and Research Center, IRCCS, Rozzano, Italy
- CNR Institute of Neuroscience, Milano, Italy
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170
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McConnell HL, Mishra A. Cells of the Blood-Brain Barrier: An Overview of the Neurovascular Unit in Health and Disease. Methods Mol Biol 2022; 2492:3-24. [PMID: 35733036 PMCID: PMC9987262 DOI: 10.1007/978-1-0716-2289-6_1] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/21/2023]
Abstract
The brain is endowed with highly specialized vasculature that is both structurally and functionally unique compared to vasculature supplying peripheral organs. The blood-brain barrier (BBB) is formed by endothelial cells of the cerebral vasculature and prevents extravasation of blood products into the brain to protect neural tissue and maintain a homeostatic environment. The BBB functions as part of the neurovascular unit (NVU), which is composed of neurons, astrocytes, and microglia in addition to the specialized endothelial cells, mural cells, and the basement membrane. Through coordinated intercellular signaling, these cells function as a dynamic unit to tightly regulate brain blood flow, vascular function, neuroimmune responses, and waste clearance. In this chapter, we review the functions of individual NVU components, describe neurovascular coupling as a classic example of NVU function, and discuss archetypal NVU pathophysiology during disease.
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Affiliation(s)
- Heather L McConnell
- Department of Neurology, Jungers Center for Neurosciences Research, Oregon Health & Science University, Portland, OR, USA
- Office of Academic Development, Houston Methodist Research Institute, Houston, TX, USA
| | - Anusha Mishra
- Department of Neurology, Jungers Center for Neurosciences Research, Oregon Health & Science University, Portland, OR, USA.
- Knight Cardiovascular Institute, Oregon Health & Science University, Portland, OR, USA.
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171
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Cader Z. Human Blood-Brain-Barrier In Vitro Models: Overview and Applications. Handb Exp Pharmacol 2022; 273:205-222. [PMID: 34935086 DOI: 10.1007/164_2021_562] [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] [Indexed: 06/14/2023]
Abstract
The human blood-brain-barrier (BBB) is a vital structure for brain health. Conversely it represents a challenge in drug development programmes that require breaching of the barrier in order to access the central nervous system. Very often brain disorders have early dysfunction of the BBB implicating an important role in pathogenesis and disease progression. The development of human in vitro models is a major advance to allow experimental studies and screening assays, although there remain outstanding questions for the field. In this chapter, the current state of the art will be reviewed, with the complementary innovative approaches to in vitro modelling described, from simple 2D-cultures to more complex multi-cell type micro-physiological systems.
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Affiliation(s)
- Zameel Cader
- Translational Molecular Neuroscience Group, University of Oxford, Oxford, UK.
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172
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The blood-brain barrier in aging and neurodegeneration. Mol Psychiatry 2022; 27:2659-2673. [PMID: 35361905 PMCID: PMC9156404 DOI: 10.1038/s41380-022-01511-z] [Citation(s) in RCA: 178] [Impact Index Per Article: 89.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/02/2021] [Revised: 01/24/2022] [Accepted: 02/24/2022] [Indexed: 12/01/2022]
Abstract
The blood-brain barrier (BBB) is vital for maintaining brain homeostasis by enabling an exquisite control of exchange of compounds between the blood and the brain parenchyma. Moreover, the BBB prevents unwanted toxins and pathogens from entering the brain. This barrier, however, breaks down with age and further disruption is a hallmark of many age-related disorders. Several drugs have been explored, thus far, to protect or restore BBB function. With the recent connection between the BBB and gut microbiota, microbial-derived metabolites have been explored for their capabilities to protect and restore BBB physiology. This review, will focus on the vital components that make up the BBB, dissect levels of disruption of the barrier, and discuss current drugs and therapeutics that maintain barrier integrity and the recent discoveries of effects microbial-derived metabolites have on BBB physiology.
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173
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Neurovascular Impairment and Therapeutic Strategies in Diabetic Retinopathy. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2021; 19:ijerph19010439. [PMID: 35010703 PMCID: PMC8744686 DOI: 10.3390/ijerph19010439] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/02/2021] [Revised: 12/25/2021] [Accepted: 12/30/2021] [Indexed: 12/15/2022]
Abstract
Diabetic retinopathy has recently been defined as a highly specific neurovascular complication of diabetes. The chronic progression of the impairment of the interdependence of neurovascular units (NVUs) is associated with the pathogenesis of diabetic retinopathy. The NVUs consist of neurons, glial cells, and vascular cells, and the interdependent relationships between these cells are disturbed under diabetic conditions. Clinicians should understand and update the current knowledge of the neurovascular impairments in diabetic retinopathy. Above all, neuronal cell death is an irreversible change, and it is directly related to vision loss in patients with diabetic retinopathy. Thus, neuroprotective and vasoprotective therapies for diabetic retinopathy must be established. Understanding the physiological and pathological interdependence of the NVUs is helpful in establishing neuroprotective and vasoprotective therapies for diabetic retinopathy. This review focuses on the pathogenesis of the neurovascular impairments and introduces possible neurovascular protective therapies for diabetic retinopathy.
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174
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Gorina YV, Salmina AB, Erofeev AI, Can Z, Bolshakova AV, Balaban PM, Bezprozvanny IB, Vlasova OL. Metabolic Plasticity of Astrocytes. J EVOL BIOCHEM PHYS+ 2021. [DOI: 10.1134/s0022093021060016] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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175
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Verkhratsky A, Parpura V, Li B, Scuderi C. Astrocytes: The Housekeepers and Guardians of the CNS. ADVANCES IN NEUROBIOLOGY 2021; 26:21-53. [PMID: 34888829 DOI: 10.1007/978-3-030-77375-5_2] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Astroglia are a diverse group of cells in the central nervous system. They are of the ectodermal, neuroepithelial origin and vary in morphology and function, yet, they can be collectively defined as cells having principle function to maintain homeostasis of the central nervous system at all levels of organisation, including homeostasis of ions, pH and neurotransmitters; supplying neurones with metabolic substrates; supporting oligodendrocytes and axons; regulating synaptogenesis, neurogenesis, and formation and maintenance of the blood-brain barrier; contributing to operation of the glymphatic system; and regulation of systemic homeostasis being central chemosensors for oxygen, CO2 and Na+. Their basic physiological features show a lack of electrical excitability (inapt to produce action potentials), but display instead a rather active excitability based on variations in cytosolic concentrations of Ca2+ and Na+. It is expression of neurotransmitter receptors, pumps and transporters at their plasmalemma, along with transports on the endoplasmic reticulum and mitochondria that exquisitely regulate the cytosolic levels of these ions, the fluctuation of which underlies most, if not all, astroglial homeostatic functions.
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Affiliation(s)
- Alexei Verkhratsky
- Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, UK.
- Achucarro Center for Neuroscience, IKERBASQUE, Basque Foundation for Science, Bilbao, Spain.
| | - Vladimir Parpura
- Department of Neurobiology, The University of Alabama at Birmingham, Birmingham, AL, USA
| | - Baoman Li
- Department of Forensic Analytical Toxicology, School of Forensic Medicine, China Medical University, Shenyang, China
| | - Caterina Scuderi
- Department of Physiology and Pharmacology "Vittorio Erspamer", SAPIENZA University of Rome, Rome, Italy
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176
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Yuan M, Wang Y, Wang S, Huang Z, Jin F, Zou Q, Li J, Pu Y, Cai Z. Bioenergetic Impairment in the Neuro-Glia-Vascular Unit: An Emerging Physiopathology during Aging. Aging Dis 2021; 12:2080-2095. [PMID: 34881087 PMCID: PMC8612602 DOI: 10.14336/ad.2021.04017] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2021] [Accepted: 04/17/2021] [Indexed: 12/28/2022] Open
Abstract
An emerging concept termed the "neuro-glia-vascular unit" (NGVU) has been established in recent years to understand the complicated mechanism of multicellular interactions among vascular cells, glial cells, and neurons. It has been proverbially reported that the NGVU is significantly associated with neurodegenerative disorders, such as Alzheimer's disease (AD), Parkinson's disease (PD), and amyotrophic lateral sclerosis (ALS). Physiological aging is an inevitable progression associated with oxidative damage, bioenergetic alterations, mitochondrial dysfunction, and neuroinflammation, which is partially similar to the pathology of AD. Thus, senescence is regarded as the background for the development of neurodegenerative diseases. With the exacerbation of global aging, senescence is an increasingly serious problem in the medical field. In this review, the coupling of each component, including neurons, glial cells, and vascular cells, in the NGVU is described in detail. Then, various mechanisms of age-dependent impairment in each part of the NGVU are discussed. Moreover, the potential bioenergetic alterations between different cell types in the NGVU are highlighted, which seems to be an emerging physiopathology associated with the aged brain. Bioenergetic intervention in the NGVU may be a new direction for studies on delaying or diminishing aging in the future.
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Affiliation(s)
- Minghao Yuan
- 1Department of Neurology, Chongqing General Hospital, University of Chinese Academy of Sciences, Chongqing, 400013, Chongqing, China.,2Chongqing School, University of Chinese Academy of Sciences, Chongqing, China.,3Chongqing Key Laboratory of Neurodegenerative Diseases, Chongqing, 400013, Chongqing, China.,4Chongqing Medical University, Chongqing, China
| | - Yangyang Wang
- 1Department of Neurology, Chongqing General Hospital, University of Chinese Academy of Sciences, Chongqing, 400013, Chongqing, China.,3Chongqing Key Laboratory of Neurodegenerative Diseases, Chongqing, 400013, Chongqing, China
| | - Shengyuan Wang
- 1Department of Neurology, Chongqing General Hospital, University of Chinese Academy of Sciences, Chongqing, 400013, Chongqing, China.,2Chongqing School, University of Chinese Academy of Sciences, Chongqing, China.,3Chongqing Key Laboratory of Neurodegenerative Diseases, Chongqing, 400013, Chongqing, China.,4Chongqing Medical University, Chongqing, China
| | - Zhenting Huang
- 1Department of Neurology, Chongqing General Hospital, University of Chinese Academy of Sciences, Chongqing, 400013, Chongqing, China.,3Chongqing Key Laboratory of Neurodegenerative Diseases, Chongqing, 400013, Chongqing, China
| | - Feng Jin
- 1Department of Neurology, Chongqing General Hospital, University of Chinese Academy of Sciences, Chongqing, 400013, Chongqing, China.,2Chongqing School, University of Chinese Academy of Sciences, Chongqing, China.,3Chongqing Key Laboratory of Neurodegenerative Diseases, Chongqing, 400013, Chongqing, China
| | - Qian Zou
- 1Department of Neurology, Chongqing General Hospital, University of Chinese Academy of Sciences, Chongqing, 400013, Chongqing, China.,3Chongqing Key Laboratory of Neurodegenerative Diseases, Chongqing, 400013, Chongqing, China
| | - Jing Li
- 1Department of Neurology, Chongqing General Hospital, University of Chinese Academy of Sciences, Chongqing, 400013, Chongqing, China.,3Chongqing Key Laboratory of Neurodegenerative Diseases, Chongqing, 400013, Chongqing, China
| | - Yinshuang Pu
- 1Department of Neurology, Chongqing General Hospital, University of Chinese Academy of Sciences, Chongqing, 400013, Chongqing, China.,3Chongqing Key Laboratory of Neurodegenerative Diseases, Chongqing, 400013, Chongqing, China
| | - Zhiyou Cai
- 1Department of Neurology, Chongqing General Hospital, University of Chinese Academy of Sciences, Chongqing, 400013, Chongqing, China.,2Chongqing School, University of Chinese Academy of Sciences, Chongqing, China.,3Chongqing Key Laboratory of Neurodegenerative Diseases, Chongqing, 400013, Chongqing, China.,4Chongqing Medical University, Chongqing, China
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177
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Crosstalk between Neuron and Glial Cells in Oxidative Injury and Neuroprotection. Int J Mol Sci 2021; 22:ijms222413315. [PMID: 34948108 PMCID: PMC8709409 DOI: 10.3390/ijms222413315] [Citation(s) in RCA: 45] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2021] [Accepted: 12/03/2021] [Indexed: 12/30/2022] Open
Abstract
To counteract oxidative stress and associated brain diseases, antioxidant systems rescue neuronal cells from oxidative stress by neutralizing reactive oxygen species and preserving gene regulation. It is necessary to understand the communication and interactions between brain cells, including neurons, astrocytes and microglia, to understand oxidative stress and antioxidant mechanisms. Here, the role of glia in the protection of neurons against oxidative injury and glia–neuron crosstalk to maintain antioxidant defense mechanisms and brain protection are reviewed. The first part of this review focuses on the role of glia in the morphological and physiological changes required for brain homeostasis under oxidative stress and antioxidant defense mechanisms. The second part focuses on the essential crosstalk between neurons and glia for redox balance in the brain for protection against oxidative stress.
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178
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Long RKM, Piatti L, Korbmacher F, Bernabeu M. Understanding parasite-brain microvascular interactions with engineered 3D blood-brain barrier models. Mol Microbiol 2021; 117:693-704. [PMID: 34837419 DOI: 10.1111/mmi.14852] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2021] [Accepted: 11/23/2021] [Indexed: 01/25/2023]
Abstract
Microbial interactions with the blood-brain barrier (BBB) can be highly pathogenic and are still not well understood. Among these, parasites present complex interactions with the brain microvasculature that are difficult to decipher using experimental animal models or reductionist 2D in vitro cultures. Novel 3D engineered blood-brain barrier models hold great promise to overcome limitations in traditional research approaches. These models better mimic the intricate 3D architecture of the brain microvasculature and recapitulate several aspects of BBB properties, physiology, and function. Moreover, they provide improved control over biophysical and biochemical experimental parameters and are compatible with advanced imaging and molecular biology techniques. Here, we review design considerations and methodologies utilized to successfully engineer BBB microvessels. Finally, we highlight the advantages and limitations of existing engineered models and propose applications to study parasite interactions with the BBB, including mechanisms of barrier disruption.
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Affiliation(s)
- Rory K M Long
- European Molecular Biology Laboratory (EMBL) Barcelona, Barcelona, Spain
| | - Livia Piatti
- European Molecular Biology Laboratory (EMBL) Barcelona, Barcelona, Spain
| | | | - Maria Bernabeu
- European Molecular Biology Laboratory (EMBL) Barcelona, Barcelona, Spain
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179
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Neurovascular Unit Alterations in the Growth-Restricted Newborn Are Improved Following Ibuprofen Treatment. Mol Neurobiol 2021; 59:1018-1040. [PMID: 34825315 DOI: 10.1007/s12035-021-02654-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2021] [Accepted: 11/17/2021] [Indexed: 10/19/2022]
Abstract
The developing brain is particularly vulnerable to foetal growth restriction (FGR) and abnormal neurodevelopment is common in the FGR infant ranging from behavioural and learning disorders to cerebral palsy. No treatment exists to protect the FGR newborn brain. Recent evidence suggests inflammation may play a key role in the mechanism responsible for the progression of brain impairment in the FGR newborn, including disruption to the neurovascular unit (NVU). We explored whether ibuprofen, an anti-inflammatory drug, could reduce NVU disruption and brain impairment in the FGR newborn. Using a preclinical FGR piglet model, ibuprofen was orally administered for 3 days from birth. FGR brains demonstrated a proinflammatory state, with changes to glial morphology (astrocytes and microglia), and blood-brain barrier disruption, assessed by IgG and albumin leakage into the brain parenchyma and a decrease in blood vessel density. Loss of interaction between astrocytic end-feet and blood vessels was evident where plasma protein leakage was present, suggestive of structural deficits to the NVU. T-cell infiltration was also evident in the parenchyma of FGR piglet brains. Ibuprofen treatment reduced the pro-inflammatory response in FGR piglets, reducing the number of activated microglia and enhancing astrocyte interaction with blood vessels. Ibuprofen also attenuated plasma protein leakage, regained astrocytic end-feet interaction around vessels, and decreased T-cell infiltration into the FGR brain. These findings suggest postnatal administration of ibuprofen modulates the inflammatory state, allowing for stronger interaction between vasculature and astrocytic end-feet to restore NVU integrity. Modulation of the NVU improves the FGR brain microenvironment and may be key to neuroprotection.
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180
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Blood-Brain Barrier in Brain Tumors: Biology and Clinical Relevance. Int J Mol Sci 2021; 22:ijms222312654. [PMID: 34884457 PMCID: PMC8657947 DOI: 10.3390/ijms222312654] [Citation(s) in RCA: 81] [Impact Index Per Article: 27.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Revised: 11/13/2021] [Accepted: 11/18/2021] [Indexed: 12/13/2022] Open
Abstract
The presence of barriers, such as the blood–brain barrier (BBB) and brain–tumor barrier (BTB), limits the penetration of antineoplastic drugs into the brain, resulting in poor response to treatments. Many techniques have been developed to overcome the presence of these barriers, including direct injections of substances by intranasal or intrathecal routes, chemical modification of drugs or constituents of BBB, inhibition of efflux pumps, physical disruption of BBB by radiofrequency electromagnetic radiation (EMP), laser-induced thermal therapy (LITT), focused ultrasounds (FUS) combined with microbubbles and convection enhanced delivery (CED). However, most of these strategies have been tested only in preclinical models or in phase 1–2 trials, and none of them have been approved for treatment of brain tumors yet. Concerning the treatment of brain metastases, many molecules have been developed in the last years with a better penetration across BBB (new generation tyrosine kinase inhibitors like osimertinib for non-small-cell lung carcinoma and neratinib/tucatinib for breast cancer), resulting in better progression-free survival and overall survival compared to older molecules. Promising studies concerning neural stem cells, CAR-T (chimeric antigen receptors) strategies and immunotherapy with checkpoint inhibitors are ongoing.
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181
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Yan L, Moriarty RA, Stroka KM. Recent progress and new challenges in modeling of human pluripotent stem cell-derived blood-brain barrier. Theranostics 2021; 11:10148-10170. [PMID: 34815809 PMCID: PMC8581424 DOI: 10.7150/thno.63195] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2021] [Accepted: 10/05/2021] [Indexed: 12/13/2022] Open
Abstract
The blood-brain barrier (BBB) is a semipermeable unit that serves to vascularize the central nervous system (CNS) while tightly regulating the movement of molecules, ions, and cells between the blood and the brain. The BBB precisely controls brain homeostasis and protects the neural tissue from toxins and pathogens. The BBB is coordinated by a tight monolayer of brain microvascular endothelial cells, which is subsequently supported by mural cells, astrocytes, and surrounding neuronal cells that regulate the barrier function with a series of specialized properties. Dysfunction of barrier properties is an important pathological feature in the progression of various neurological diseases. In vitro BBB models recapitulating the physiological and diseased states are important tools to understand the pathological mechanism and to serve as a platform to screen potential drugs. Recent advances in this field have stemmed from the use of pluripotent stem cells (PSCs). Various cell types of the BBB such as brain microvascular endothelial cells (BMECs), pericytes, and astrocytes have been derived from PSCs and synergistically incorporated to model the complex BBB structure in vitro. In this review, we summarize the most recent protocols and techniques for the differentiation of major cell types of the BBB. We also discuss the progress of BBB modeling by using PSC-derived cells and perspectives on how to reproduce more natural BBBs in vitro.
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Affiliation(s)
- Li Yan
- Fischell Department of Bioengineering, University of Maryland, College Park, MD 20742, USA
| | - Rebecca A. Moriarty
- Fischell Department of Bioengineering, University of Maryland, College Park, MD 20742, USA
| | - Kimberly M. Stroka
- Fischell Department of Bioengineering, University of Maryland, College Park, MD 20742, USA
- Biophysics Program, University of Maryland, College Park, MD 20742, USA
- Center for Stem Cell Biology and Regenerative Medicine, University of Maryland, Baltimore, MD 21201, USA
- Marlene and Stewart Greenebaum Comprehensive Cancer Center, University of Maryland, Baltimore, MD 21201, USA
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182
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Galea I. The blood-brain barrier in systemic infection and inflammation. Cell Mol Immunol 2021; 18:2489-2501. [PMID: 34594000 PMCID: PMC8481764 DOI: 10.1038/s41423-021-00757-x] [Citation(s) in RCA: 210] [Impact Index Per Article: 70.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Accepted: 08/04/2021] [Indexed: 02/08/2023] Open
Abstract
The vascular blood-brain barrier is a highly regulated interface between the blood and brain. Its primary function is to protect central neurons while signaling the presence of systemic inflammation and infection to the brain to enable a protective sickness behavior response. With increasing degrees and duration of systemic inflammation, the vascular blood-brain barrier becomes more permeable to solutes, undergoes an increase in lymphocyte trafficking, and is infiltrated by innate immune cells; endothelial cell damage may occasionally occur. Perturbation of neuronal function results in the clinical features of encephalopathy. Here, the molecular and cellular anatomy of the vascular blood-brain barrier is reviewed, first in a healthy context and second in a systemic inflammatory context. Distinct from the molecular and cellular mediators of the blood-brain barrier's response to inflammation, several moderators influence the direction and magnitude at genetic, system, cellular and molecular levels. These include sex, genetic background, age, pre-existing brain pathology, systemic comorbidity, and gut dysbiosis. Further progress is required to define and measure mediators and moderators of the blood-brain barrier's response to systemic inflammation in order to explain the heterogeneity observed in animal and human studies.
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Affiliation(s)
- Ian Galea
- grid.5491.90000 0004 1936 9297Clinical Neurosciences, Clinical & Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton, SO16 6YD UK
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183
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Cleland NRW, Al-Juboori SI, Dobrinskikh E, Bruce KD. Altered substrate metabolism in neurodegenerative disease: new insights from metabolic imaging. J Neuroinflammation 2021; 18:248. [PMID: 34711251 PMCID: PMC8555332 DOI: 10.1186/s12974-021-02305-w] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2021] [Accepted: 10/21/2021] [Indexed: 12/13/2022] Open
Abstract
Neurodegenerative diseases (NDs), such as Alzheimer's disease (AD), Parkinson's disease (PD) and multiple sclerosis (MS), are relatively common and devastating neurological disorders. For example, there are 6 million individuals living with AD in the United States, a number that is projected to grow to 14 million by the year 2030. Importantly, AD, PD and MS are all characterized by the lack of a true disease-modifying therapy that is able to reverse or halt disease progression. In addition, the existing standard of care for most NDs only addresses the symptoms of the disease. Therefore, alternative strategies that target mechanisms underlying the neuropathogenesis of disease are much needed. Recent studies have indicated that metabolic alterations in neurons and glia are commonly observed in AD, PD and MS and lead to changes in cell function that can either precede or protect against disease onset and progression. Specifically, single-cell RNAseq studies have shown that AD progression is tightly linked to the metabolic phenotype of microglia, the key immune effector cells of the brain. However, these analyses involve removing cells from their native environment and performing measurements in vitro, influencing metabolic status. Therefore, technical approaches that can accurately assess cell-specific metabolism in situ have the potential to be transformative to our understanding of the mechanisms driving AD. Here, we review our current understanding of metabolism in both neurons and glia during homeostasis and disease. We also evaluate recent advances in metabolic imaging, and discuss how emerging modalities, such as fluorescence lifetime imaging microscopy (FLIM) have the potential to determine how metabolic perturbations may drive the progression of NDs. Finally, we propose that the temporal, regional, and cell-specific characterization of brain metabolism afforded by FLIM will be a critical first step in the rational design of metabolism-focused interventions that delay or even prevent NDs.
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Affiliation(s)
- Nicholas R W Cleland
- Endocrinology, Metabolism and Diabetes, Division of Endocrinology, Metabolism and Diabetes, Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, USA
- School of Medicine, University of Colorado Anschutz Medical Campus, Aurora, USA
| | - Saif I Al-Juboori
- Section of Neonatology, Department of Pediatrics, University of Colorado Anschutz Medical Campus, Aurora, USA
| | - Evgenia Dobrinskikh
- Section of Neonatology, Department of Pediatrics, University of Colorado Anschutz Medical Campus, Aurora, USA
- Division of Pulmonary Sciences and Critical Care, Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, USA
| | - Kimberley D Bruce
- Endocrinology, Metabolism and Diabetes, Division of Endocrinology, Metabolism and Diabetes, Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, USA.
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184
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Astrocyte Gliotransmission in the Regulation of Systemic Metabolism. Metabolites 2021; 11:metabo11110732. [PMID: 34822390 PMCID: PMC8623475 DOI: 10.3390/metabo11110732] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2021] [Revised: 10/25/2021] [Accepted: 10/26/2021] [Indexed: 12/28/2022] Open
Abstract
Normal brain function highly relies on the appropriate functioning of astrocytes. These glial cells are strategically situated between blood vessels and neurons, provide significant substrate support to neuronal demand, and are sensitive to neuronal activity and energy-related molecules. Astrocytes respond to many metabolic conditions and regulate a wide array of physiological processes, including cerebral vascular remodeling, glucose sensing, feeding, and circadian rhythms for the control of systemic metabolism and behavior-related responses. This regulation ultimately elicits counterregulatory mechanisms in order to couple whole-body energy availability with brain function. Therefore, understanding the role of astrocyte crosstalk with neighboring cells via the release of molecules, e.g., gliotransmitters, into the parenchyma in response to metabolic and neuronal cues is of fundamental relevance to elucidate the distinct roles of these glial cells in the neuroendocrine control of metabolism. Here, we review the mechanisms underlying astrocyte-released gliotransmitters that have been reported to be crucial for maintaining homeostatic regulation of systemic metabolism.
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185
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Zisis E, Keller D, Kanari L, Arnaudon A, Gevaert M, Delemontex T, Coste B, Foni A, Abdellah M, Calì C, Hess K, Magistretti PJ, Schürmann F, Markram H. Digital Reconstruction of the Neuro-Glia-Vascular Architecture. Cereb Cortex 2021; 31:5686-5703. [PMID: 34387659 PMCID: PMC8568010 DOI: 10.1093/cercor/bhab254] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Revised: 07/05/2021] [Accepted: 07/06/2021] [Indexed: 01/21/2023] Open
Abstract
Astrocytes connect the vasculature to neurons mediating the supply of nutrients and biochemicals. They are involved in a growing number of physiological and pathophysiological processes that result from biophysical, physiological, and molecular interactions in this neuro-glia-vascular ensemble (NGV). The lack of a detailed cytoarchitecture severely restricts the understanding of how they support brain function. To address this problem, we used data from multiple sources to create a data-driven digital reconstruction of the NGV at micrometer anatomical resolution. We reconstructed 0.2 mm3 of the rat somatosensory cortex with 16 000 morphologically detailed neurons, 2500 protoplasmic astrocytes, and its microvasculature. The consistency of the reconstruction with a wide array of experimental measurements allows novel predictions of the NGV organization, allowing the anatomical reconstruction of overlapping astrocytic microdomains and the quantification of endfeet connecting each astrocyte to the vasculature, as well as the extent to which they cover the latter. Structural analysis showed that astrocytes optimize their positions to provide uniform vascular coverage for trophic support and signaling. However, this optimal organization rapidly declines as their density increases. The NGV digital reconstruction is a resource that will enable a better understanding of the anatomical principles and geometric constraints, which govern how astrocytes support brain function.
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Affiliation(s)
- Eleftherios Zisis
- Blue Brain Project, École polytechnique fédérale de Lausanne (EPFL), Campus Biotech, Geneva 1202, Switzerland
| | - Daniel Keller
- Blue Brain Project, École polytechnique fédérale de Lausanne (EPFL), Campus Biotech, Geneva 1202, Switzerland
| | - Lida Kanari
- Blue Brain Project, École polytechnique fédérale de Lausanne (EPFL), Campus Biotech, Geneva 1202, Switzerland
| | - Alexis Arnaudon
- Blue Brain Project, École polytechnique fédérale de Lausanne (EPFL), Campus Biotech, Geneva 1202, Switzerland
| | - Michael Gevaert
- Blue Brain Project, École polytechnique fédérale de Lausanne (EPFL), Campus Biotech, Geneva 1202, Switzerland
| | - Thomas Delemontex
- Blue Brain Project, École polytechnique fédérale de Lausanne (EPFL), Campus Biotech, Geneva 1202, Switzerland
| | - Benoît Coste
- Blue Brain Project, École polytechnique fédérale de Lausanne (EPFL), Campus Biotech, Geneva 1202, Switzerland
| | - Alessandro Foni
- Blue Brain Project, École polytechnique fédérale de Lausanne (EPFL), Campus Biotech, Geneva 1202, Switzerland
| | - Marwan Abdellah
- Blue Brain Project, École polytechnique fédérale de Lausanne (EPFL), Campus Biotech, Geneva 1202, Switzerland
| | - Corrado Calì
- Neuroscience Institute Cavalieri Ottolenghi, Orbassano, Turin 10043, Italy
- Department of Neuroscience, University of Torino, Torino 10126, Italy
- Biological and Environmental Sciences and Engineering Division, King Abdullah University of Science and Technology (KAUST), Thuwal 23955, Saudi Arabia
| | - Kathryn Hess
- Laboratory for Topology and Neuroscience, Brain Mind Institute, École polytechnique fédérale de Lausanne (EPFL), Lausanne 1015, Switzerland
| | - Pierre Julius Magistretti
- Biological and Environmental Sciences and Engineering Division, King Abdullah University of Science and Technology (KAUST), Thuwal 23955, Saudi Arabia
| | - Felix Schürmann
- Blue Brain Project, École polytechnique fédérale de Lausanne (EPFL), Campus Biotech, Geneva 1202, Switzerland
| | - Henry Markram
- Blue Brain Project, École polytechnique fédérale de Lausanne (EPFL), Campus Biotech, Geneva 1202, Switzerland
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186
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Klostranec JM, Vucevic D, Bhatia KD, Kortman HGJ, Krings T, Murphy KP, terBrugge KG, Mikulis DJ. Current Concepts in Intracranial Interstitial Fluid Transport and the Glymphatic System: Part I-Anatomy and Physiology. Radiology 2021; 301:502-514. [PMID: 34665028 DOI: 10.1148/radiol.2021202043] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Normal physiologic function of organs requires a circulation of interstitial fluid to deliver nutrients and clear cellular waste products. Lymphatic vessels serve as collectors of this fluid in most organs; however, these vessels are absent in the central nervous system. How the central nervous system maintains tight control of extracellular conditions has been a fundamental question in neuroscience until recent discovery of the glial-lymphatic, or glymphatic, system was made this past decade. Networks of paravascular channels surrounding pial and parenchymal arteries and veins were found that extend into the walls of capillaries to allow fluid transport and exchange between the interstitial and cerebrospinal fluid spaces. The currently understood anatomy and physiology of the glymphatic system is reviewed, with the paravascular space presented as an intrinsic component of healthy pial and parenchymal cerebral blood vessels. Glymphatic system behavior in animal models of health and disease, and its enhanced function during sleep, are discussed. The evolving understanding of glymphatic system characteristics is then used to provide a current interpretation of its physiology that can be helpful for radiologists when interpreting neuroimaging investigations.
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Affiliation(s)
- Jesse M Klostranec
- From the Montreal Neurologic Institute and Hospital, Department of Diagnostic and Interventional Neuroradiology, McGill University Health Centre, 3801 Rue University, Montréal, QC, Canada H3A 2B4 (J.M.K.); Department of Medical Imaging, University of Toronto, Toronto, Canada (J.M.K., D.V., K.D.B., H.G.J.K., T.K., K.P.M., K.G.t.B., D.J.M.); Division of Neuroradiology, Toronto Western Hospital, University Health Network, Toronto, Canada (J.M.K., D.V., K.D.B., H.G.J.K., T.K., K.P.M., K.G.t.B., D.J.M.); Centre Hospitalier de l'Université de Montreal (CHUM), Department of Radiology, Service of Neuroradiology, l'Université de Montreal, Montréal, Canada (J.M.K.); Department of Materials Science & Engineering, Faculty of Applied Science & Engineering, University of Toronto, Toronto, Canada (D.V.); Department of Medical Imaging, Sydney Children's Hospitals Network, Westmead, Australia (K.D.B.); and Division of Neurosurgery, Department of Surgery, University of Toronto, Toronto, Canada (T.K., K.G.t.B.)
| | - Diana Vucevic
- From the Montreal Neurologic Institute and Hospital, Department of Diagnostic and Interventional Neuroradiology, McGill University Health Centre, 3801 Rue University, Montréal, QC, Canada H3A 2B4 (J.M.K.); Department of Medical Imaging, University of Toronto, Toronto, Canada (J.M.K., D.V., K.D.B., H.G.J.K., T.K., K.P.M., K.G.t.B., D.J.M.); Division of Neuroradiology, Toronto Western Hospital, University Health Network, Toronto, Canada (J.M.K., D.V., K.D.B., H.G.J.K., T.K., K.P.M., K.G.t.B., D.J.M.); Centre Hospitalier de l'Université de Montreal (CHUM), Department of Radiology, Service of Neuroradiology, l'Université de Montreal, Montréal, Canada (J.M.K.); Department of Materials Science & Engineering, Faculty of Applied Science & Engineering, University of Toronto, Toronto, Canada (D.V.); Department of Medical Imaging, Sydney Children's Hospitals Network, Westmead, Australia (K.D.B.); and Division of Neurosurgery, Department of Surgery, University of Toronto, Toronto, Canada (T.K., K.G.t.B.)
| | - Kartik D Bhatia
- From the Montreal Neurologic Institute and Hospital, Department of Diagnostic and Interventional Neuroradiology, McGill University Health Centre, 3801 Rue University, Montréal, QC, Canada H3A 2B4 (J.M.K.); Department of Medical Imaging, University of Toronto, Toronto, Canada (J.M.K., D.V., K.D.B., H.G.J.K., T.K., K.P.M., K.G.t.B., D.J.M.); Division of Neuroradiology, Toronto Western Hospital, University Health Network, Toronto, Canada (J.M.K., D.V., K.D.B., H.G.J.K., T.K., K.P.M., K.G.t.B., D.J.M.); Centre Hospitalier de l'Université de Montreal (CHUM), Department of Radiology, Service of Neuroradiology, l'Université de Montreal, Montréal, Canada (J.M.K.); Department of Materials Science & Engineering, Faculty of Applied Science & Engineering, University of Toronto, Toronto, Canada (D.V.); Department of Medical Imaging, Sydney Children's Hospitals Network, Westmead, Australia (K.D.B.); and Division of Neurosurgery, Department of Surgery, University of Toronto, Toronto, Canada (T.K., K.G.t.B.)
| | - Hans G J Kortman
- From the Montreal Neurologic Institute and Hospital, Department of Diagnostic and Interventional Neuroradiology, McGill University Health Centre, 3801 Rue University, Montréal, QC, Canada H3A 2B4 (J.M.K.); Department of Medical Imaging, University of Toronto, Toronto, Canada (J.M.K., D.V., K.D.B., H.G.J.K., T.K., K.P.M., K.G.t.B., D.J.M.); Division of Neuroradiology, Toronto Western Hospital, University Health Network, Toronto, Canada (J.M.K., D.V., K.D.B., H.G.J.K., T.K., K.P.M., K.G.t.B., D.J.M.); Centre Hospitalier de l'Université de Montreal (CHUM), Department of Radiology, Service of Neuroradiology, l'Université de Montreal, Montréal, Canada (J.M.K.); Department of Materials Science & Engineering, Faculty of Applied Science & Engineering, University of Toronto, Toronto, Canada (D.V.); Department of Medical Imaging, Sydney Children's Hospitals Network, Westmead, Australia (K.D.B.); and Division of Neurosurgery, Department of Surgery, University of Toronto, Toronto, Canada (T.K., K.G.t.B.)
| | - Timo Krings
- From the Montreal Neurologic Institute and Hospital, Department of Diagnostic and Interventional Neuroradiology, McGill University Health Centre, 3801 Rue University, Montréal, QC, Canada H3A 2B4 (J.M.K.); Department of Medical Imaging, University of Toronto, Toronto, Canada (J.M.K., D.V., K.D.B., H.G.J.K., T.K., K.P.M., K.G.t.B., D.J.M.); Division of Neuroradiology, Toronto Western Hospital, University Health Network, Toronto, Canada (J.M.K., D.V., K.D.B., H.G.J.K., T.K., K.P.M., K.G.t.B., D.J.M.); Centre Hospitalier de l'Université de Montreal (CHUM), Department of Radiology, Service of Neuroradiology, l'Université de Montreal, Montréal, Canada (J.M.K.); Department of Materials Science & Engineering, Faculty of Applied Science & Engineering, University of Toronto, Toronto, Canada (D.V.); Department of Medical Imaging, Sydney Children's Hospitals Network, Westmead, Australia (K.D.B.); and Division of Neurosurgery, Department of Surgery, University of Toronto, Toronto, Canada (T.K., K.G.t.B.)
| | - Kieran P Murphy
- From the Montreal Neurologic Institute and Hospital, Department of Diagnostic and Interventional Neuroradiology, McGill University Health Centre, 3801 Rue University, Montréal, QC, Canada H3A 2B4 (J.M.K.); Department of Medical Imaging, University of Toronto, Toronto, Canada (J.M.K., D.V., K.D.B., H.G.J.K., T.K., K.P.M., K.G.t.B., D.J.M.); Division of Neuroradiology, Toronto Western Hospital, University Health Network, Toronto, Canada (J.M.K., D.V., K.D.B., H.G.J.K., T.K., K.P.M., K.G.t.B., D.J.M.); Centre Hospitalier de l'Université de Montreal (CHUM), Department of Radiology, Service of Neuroradiology, l'Université de Montreal, Montréal, Canada (J.M.K.); Department of Materials Science & Engineering, Faculty of Applied Science & Engineering, University of Toronto, Toronto, Canada (D.V.); Department of Medical Imaging, Sydney Children's Hospitals Network, Westmead, Australia (K.D.B.); and Division of Neurosurgery, Department of Surgery, University of Toronto, Toronto, Canada (T.K., K.G.t.B.)
| | - Karel G terBrugge
- From the Montreal Neurologic Institute and Hospital, Department of Diagnostic and Interventional Neuroradiology, McGill University Health Centre, 3801 Rue University, Montréal, QC, Canada H3A 2B4 (J.M.K.); Department of Medical Imaging, University of Toronto, Toronto, Canada (J.M.K., D.V., K.D.B., H.G.J.K., T.K., K.P.M., K.G.t.B., D.J.M.); Division of Neuroradiology, Toronto Western Hospital, University Health Network, Toronto, Canada (J.M.K., D.V., K.D.B., H.G.J.K., T.K., K.P.M., K.G.t.B., D.J.M.); Centre Hospitalier de l'Université de Montreal (CHUM), Department of Radiology, Service of Neuroradiology, l'Université de Montreal, Montréal, Canada (J.M.K.); Department of Materials Science & Engineering, Faculty of Applied Science & Engineering, University of Toronto, Toronto, Canada (D.V.); Department of Medical Imaging, Sydney Children's Hospitals Network, Westmead, Australia (K.D.B.); and Division of Neurosurgery, Department of Surgery, University of Toronto, Toronto, Canada (T.K., K.G.t.B.)
| | - David J Mikulis
- From the Montreal Neurologic Institute and Hospital, Department of Diagnostic and Interventional Neuroradiology, McGill University Health Centre, 3801 Rue University, Montréal, QC, Canada H3A 2B4 (J.M.K.); Department of Medical Imaging, University of Toronto, Toronto, Canada (J.M.K., D.V., K.D.B., H.G.J.K., T.K., K.P.M., K.G.t.B., D.J.M.); Division of Neuroradiology, Toronto Western Hospital, University Health Network, Toronto, Canada (J.M.K., D.V., K.D.B., H.G.J.K., T.K., K.P.M., K.G.t.B., D.J.M.); Centre Hospitalier de l'Université de Montreal (CHUM), Department of Radiology, Service of Neuroradiology, l'Université de Montreal, Montréal, Canada (J.M.K.); Department of Materials Science & Engineering, Faculty of Applied Science & Engineering, University of Toronto, Toronto, Canada (D.V.); Department of Medical Imaging, Sydney Children's Hospitals Network, Westmead, Australia (K.D.B.); and Division of Neurosurgery, Department of Surgery, University of Toronto, Toronto, Canada (T.K., K.G.t.B.)
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187
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Virtuoso A, Colangelo AM, Maggio N, Fennig U, Weinberg N, Papa M, De Luca C. The Spatiotemporal Coupling: Regional Energy Failure and Aberrant Proteins in Neurodegenerative Diseases. Int J Mol Sci 2021; 22:11304. [PMID: 34768733 PMCID: PMC8583302 DOI: 10.3390/ijms222111304] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2021] [Revised: 10/15/2021] [Accepted: 10/17/2021] [Indexed: 12/14/2022] Open
Abstract
The spatial and temporal coordination of each element is a pivotal characteristic of systems, and the central nervous system (CNS) is not an exception. Glial elements and the vascular interface have been considered more recently, together with the extracellular matrix and the immune system. However, the knowledge of the single-element configuration is not sufficient to predict physiological or pathological long-lasting changes. Ionic currents, complex molecular cascades, genomic rearrangement, and the regional energy demand can be different even in neighboring cells of the same phenotype, and their differential expression could explain the region-specific progression of the most studied neurodegenerative diseases. We here reviewed the main nodes and edges of the system, which could be studied to develop a comprehensive knowledge of CNS plasticity from the neurovascular unit to the synaptic cleft. The future goal is to redefine the modeling of synaptic plasticity and achieve a better understanding of neurological diseases, pointing out cellular, subcellular, and molecular components that couple in specific neuroanatomical and functional regions.
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Affiliation(s)
- Assunta Virtuoso
- Laboratory of Neuronal Networks, Department of Mental and Physical Health and Preventive Medicine, University of Campania ‘‘Luigi Vanvitelli”, 80138 Naples, Italy; (A.V.); (C.D.L.)
| | - Anna Maria Colangelo
- SYSBIO Centre of Systems Biology ISBE-IT, University of Milano-Bicocca, 20126 Milan, Italy;
- Laboratory of Neuroscience “R. Levi-Montalcini”, Department of Biotechnology and Biosciences, University of Milano-Bicocca, 20126 Milan, Italy
| | - Nicola Maggio
- Department of Neurology and Neurosurgery, Sackler Faculty of Medicine, Sagol School of Neuroscience, Tel Aviv University, Tel Aviv 6997801, Israel; (N.M.); (U.F.); (N.W.)
- Department of Neurology, The Chaim Sheba Medical Center at Tel HaShomer, Ramat Gan 52662, Israel
| | - Uri Fennig
- Department of Neurology and Neurosurgery, Sackler Faculty of Medicine, Sagol School of Neuroscience, Tel Aviv University, Tel Aviv 6997801, Israel; (N.M.); (U.F.); (N.W.)
- Department of Neurology, The Chaim Sheba Medical Center at Tel HaShomer, Ramat Gan 52662, Israel
| | - Nitai Weinberg
- Department of Neurology and Neurosurgery, Sackler Faculty of Medicine, Sagol School of Neuroscience, Tel Aviv University, Tel Aviv 6997801, Israel; (N.M.); (U.F.); (N.W.)
- Department of Neurology, The Chaim Sheba Medical Center at Tel HaShomer, Ramat Gan 52662, Israel
| | - Michele Papa
- Laboratory of Neuronal Networks, Department of Mental and Physical Health and Preventive Medicine, University of Campania ‘‘Luigi Vanvitelli”, 80138 Naples, Italy; (A.V.); (C.D.L.)
- SYSBIO Centre of Systems Biology ISBE-IT, University of Milano-Bicocca, 20126 Milan, Italy;
| | - Ciro De Luca
- Laboratory of Neuronal Networks, Department of Mental and Physical Health and Preventive Medicine, University of Campania ‘‘Luigi Vanvitelli”, 80138 Naples, Italy; (A.V.); (C.D.L.)
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188
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Andoh NE, Gyan BA. The Potential Roles of Glial Cells in the Neuropathogenesis of Cerebral Malaria. Front Cell Infect Microbiol 2021; 11:741370. [PMID: 34692564 PMCID: PMC8529055 DOI: 10.3389/fcimb.2021.741370] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2021] [Accepted: 09/17/2021] [Indexed: 01/02/2023] Open
Abstract
Cerebral malaria (CM) is a severe neurological complication of malaria caused by the Plasmodium falciparum parasite. It is one of the leading causes of death in children under 5 years of age in Sub-Saharan Africa. CM is associated with blood-brain barrier disruption and long-term neurological sequelae in survivors of CM. Despite the vast amount of research on cerebral malaria, the cause of neurological sequelae observed in CM patients is poorly understood. In this article, the potential roles of glial cells, astrocytes, and microglia, in cerebral malaria pathogenesis are reviewed. The possible mechanisms by which glial cells contribute to neurological damage in CM patients are also examined.
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Affiliation(s)
- Nana Efua Andoh
- Noguchi Memorial Institute for Medical Research, Department of Parasitology, University of Ghana, Accra, Ghana
| | - Ben Adu Gyan
- Noguchi Memorial Institute for Medical Research, Department of Immunology, University of Ghana, Accra, Ghana
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189
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Song J, Yang X, Zhang M, Wang C, Chen L. Glutamate Metabolism in Mitochondria is Closely Related to Alzheimer's Disease. J Alzheimers Dis 2021; 84:557-578. [PMID: 34602474 DOI: 10.3233/jad-210595] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Glutamate is the main excitatory neurotransmitter in the brain, and its excitatory neurotoxicity is closely related to the occurrence and development of Alzheimer's disease. However, increasing evidence shows that in the process of Alzheimer's disease, glutamate is not only limited to its excitotoxicity as a neurotransmitter but also related to the disorder of its metabolic balance. The balance of glutamate metabolism in the brain is an important determinant of central nervous system health, and the maintenance of this balance is closely related to glutamate uptake, glutamate circulation, intracellular mitochondrial transport, and mitochondrial metabolism. In this paper, we intend to elaborate the key role of mitochondrial glutamate metabolism in the pathogenesis of Alzheimer's disease and review glutamate metabolism in mitochondria as a potential target in the treatment of Alzheimer's disease.
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Affiliation(s)
- Jiayi Song
- Department of Pharmacology, Basic College of Medicine, Jilin University, Changchun, People's Republic of China.,Cadre's Ward, The First Hospital of Jilin University, Changchun, People's Republic of China
| | - Xuehan Yang
- Department of Pharmacology, Basic College of Medicine, Jilin University, Changchun, People's Republic of China
| | - Ming Zhang
- Department of Pharmacology, Basic College of Medicine, Jilin University, Changchun, People's Republic of China
| | - Chunyan Wang
- Cadre's Ward, The First Hospital of Jilin University, Changchun, People's Republic of China
| | - Li Chen
- Department of Pharmacology, Basic College of Medicine, Jilin University, Changchun, People's Republic of China
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190
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Stokum JA, Shim B, Huang W, Kane M, Smith JA, Gerzanich V, Simard JM. A large portion of the astrocyte proteome is dedicated to perivascular endfeet, including critical components of the electron transport chain. J Cereb Blood Flow Metab 2021; 41:2546-2560. [PMID: 33818185 PMCID: PMC8504955 DOI: 10.1177/0271678x211004182] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
The perivascular astrocyte endfoot is a specialized and diffusion-limited subcellular compartment that fully ensheathes the cerebral vasculature. Despite their ubiquitous presence, a detailed understanding of endfoot physiology remains elusive, in part due to a limited understanding of the proteins that distinguish the endfoot from the greater astrocyte body. Here, we developed a technique to isolate astrocyte endfeet from brain tissue, which was used to study the endfoot proteome in comparison to the astrocyte somata. In our approach, brain microvessels, which retain their endfoot processes, were isolated from mouse brain and dissociated, whereupon endfeet were recovered using an antibody-based column astrocyte isolation kit. Our findings expand the known set of proteins enriched at the endfoot from 10 to 516, which comprised more than 1/5th of the entire detected astrocyte proteome. Numerous critical electron transport chain proteins were expressed only at the endfeet, while enzymes involved in glycogen storage were distributed to the somata, indicating subcellular metabolic compartmentalization. The endfoot proteome also included numerous proteins that, while known to have important contributions to blood-brain barrier function, were not previously known to localize to the endfoot. Our findings highlight the importance of the endfoot and suggest new routes of investigation into endfoot function.
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Affiliation(s)
- Jesse A Stokum
- Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Bosung Shim
- Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Weiliang Huang
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Maryland, Baltimore, MD, USA
| | - Maureen Kane
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Maryland, Baltimore, MD, USA
| | - Jesse A Smith
- Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Volodymyr Gerzanich
- Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, MD, USA
| | - J Marc Simard
- Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, MD, USA.,Department of Pathology, University of Maryland School of Medicine, Baltimore, MD, USA.,Department of Physiology, University of Maryland School of Medicine, Baltimore, MD, USA
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191
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Neumaier F, Zlatopolskiy BD, Neumaier B. Drug Penetration into the Central Nervous System: Pharmacokinetic Concepts and In Vitro Model Systems. Pharmaceutics 2021; 13:1542. [PMID: 34683835 PMCID: PMC8538549 DOI: 10.3390/pharmaceutics13101542] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2021] [Revised: 09/17/2021] [Accepted: 09/20/2021] [Indexed: 12/22/2022] Open
Abstract
Delivery of most drugs into the central nervous system (CNS) is restricted by the blood-brain barrier (BBB), which remains a significant bottleneck for development of novel CNS-targeted therapeutics or molecular tracers for neuroimaging. Consistent failure to reliably predict drug efficiency based on single measures for the rate or extent of brain penetration has led to the emergence of a more holistic framework that integrates data from various in vivo, in situ and in vitro assays to obtain a comprehensive description of drug delivery to and distribution within the brain. Coupled with ongoing development of suitable in vitro BBB models, this integrated approach promises to reduce the incidence of costly late-stage failures in CNS drug development, and could help to overcome some of the technical, economic and ethical issues associated with in vivo studies in animal models. Here, we provide an overview of BBB structure and function in vivo, and a summary of the pharmacokinetic parameters that can be used to determine and predict the rate and extent of drug penetration into the brain. We also review different in vitro models with regard to their inherent shortcomings and potential usefulness for development of fast-acting drugs or neurotracers labeled with short-lived radionuclides. In this regard, a special focus has been set on those systems that are sufficiently well established to be used in laboratories without significant bioengineering expertise.
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Affiliation(s)
- Felix Neumaier
- Institute of Radiochemistry and Experimental Molecular Imaging, Faculty of Medicine and University Hospital Cologne, University of Cologne, Kerpener Str. 62, 50937 Cologne, Germany; (B.D.Z.); (B.N.)
- Forschungszentrum Jülich GmbH, Institute of Neuroscience and Medicine, Nuclear Chemistry (INM-5), Wilhelm-Johnen-Str., 52428 Jülich, Germany
| | - Boris D. Zlatopolskiy
- Institute of Radiochemistry and Experimental Molecular Imaging, Faculty of Medicine and University Hospital Cologne, University of Cologne, Kerpener Str. 62, 50937 Cologne, Germany; (B.D.Z.); (B.N.)
- Forschungszentrum Jülich GmbH, Institute of Neuroscience and Medicine, Nuclear Chemistry (INM-5), Wilhelm-Johnen-Str., 52428 Jülich, Germany
| | - Bernd Neumaier
- Institute of Radiochemistry and Experimental Molecular Imaging, Faculty of Medicine and University Hospital Cologne, University of Cologne, Kerpener Str. 62, 50937 Cologne, Germany; (B.D.Z.); (B.N.)
- Forschungszentrum Jülich GmbH, Institute of Neuroscience and Medicine, Nuclear Chemistry (INM-5), Wilhelm-Johnen-Str., 52428 Jülich, Germany
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192
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Chen S, Shao L, Ma L. Cerebral Edema Formation After Stroke: Emphasis on Blood-Brain Barrier and the Lymphatic Drainage System of the Brain. Front Cell Neurosci 2021; 15:716825. [PMID: 34483842 PMCID: PMC8415457 DOI: 10.3389/fncel.2021.716825] [Citation(s) in RCA: 56] [Impact Index Per Article: 18.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2021] [Accepted: 07/20/2021] [Indexed: 01/01/2023] Open
Abstract
Brain edema is a severe stroke complication that is associated with prolonged hospitalization and poor outcomes. Swollen tissues in the brain compromise cerebral perfusion and may also result in transtentorial herniation. As a physical and biochemical barrier between the peripheral circulation and the central nervous system (CNS), the blood–brain barrier (BBB) plays a vital role in maintaining the stable microenvironment of the CNS. Under pathological conditions, such as ischemic stroke, the dysfunction of the BBB results in increased paracellular permeability, directly contributing to the extravasation of blood components into the brain and causing cerebral vasogenic edema. Recent studies have led to the discovery of the glymphatic system and meningeal lymphatic vessels, which provide a channel for cerebrospinal fluid (CSF) to enter the brain and drain to nearby lymph nodes and communicate with the peripheral immune system, modulating immune surveillance and brain responses. A deeper understanding of the function of the cerebral lymphatic system calls into question the known mechanisms of cerebral edema after stroke. In this review, we first discuss how BBB disruption after stroke can cause or contribute to cerebral edema from the perspective of molecular and cellular pathophysiology. Finally, we discuss how the cerebral lymphatic system participates in the formation of cerebral edema after stroke and summarize the pathophysiological process of cerebral edema formation after stroke from the two directions of the BBB and cerebral lymphatic system.
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Affiliation(s)
- Sichao Chen
- Department of Neurosurgery, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Linqian Shao
- Department of Neurosurgery, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Li Ma
- Department of Neurosurgery, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China
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193
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Semyanov A, Verkhratsky A. Astrocytic processes: from tripartite synapses to the active milieu. Trends Neurosci 2021; 44:781-792. [PMID: 34479758 DOI: 10.1016/j.tins.2021.07.006] [Citation(s) in RCA: 114] [Impact Index Per Article: 38.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2021] [Revised: 07/09/2021] [Accepted: 07/20/2021] [Indexed: 12/16/2022]
Abstract
We define a new concept of 'active milieu' that unifies all components of nervous tissue (neuronal and glial compartments, extracellular space, extracellular matrix, and vasculature) into a dynamic information processing system. Within this framework, we focus on the role of astrocytic processes, classified into organelle-containing branches and organelle-free leaflets. We argue that astrocytic branches with emanating leaflets are homologous to dendritic shafts with spines. Within the active milieu, astrocytic processes are engaged in reciprocal interactions with neuronal compartments and communication with other cellular and non-cellular elements of the nervous tissue.
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Affiliation(s)
- Alexey Semyanov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, 117997, Russia; Faculty of Biology, Moscow State University, Moscow, Russia; Sechenov First Moscow State Medical University, Moscow, Russia.
| | - Alexei Verkhratsky
- Sechenov First Moscow State Medical University, Moscow, Russia; Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, UK; Achucarro Center for Neuroscience, IKERBASQUE, Basque Foundation for Science, 48011 Bilbao, Spain; Department of Neurosciences, University of the Basque Country UPV/EHU and CIBERNED, Leioa, Spain.
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194
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Hanafy AS, Dietrich D, Fricker G, Lamprecht A. Blood-brain barrier models: Rationale for selection. Adv Drug Deliv Rev 2021; 176:113859. [PMID: 34246710 DOI: 10.1016/j.addr.2021.113859] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2021] [Revised: 06/21/2021] [Accepted: 07/01/2021] [Indexed: 01/21/2023]
Abstract
Brain delivery is a broad research area, the outcomes of which are far hindered by the limited permeability of the blood-brain barrier (BBB). Over the last century, research has been revealing the BBB complexity and the crosstalk between its cellular and molecular components. Pathologically, BBB alterations may precede as well as be concomitant or lead to brain diseases. To simulate the BBB and investigate options for drug delivery, several in vitro, in vivo, ex vivo, in situ and in silico models are used. Hundreds of drug delivery vehicles successfully pass preclinical trials but fail in clinical settings. Inadequate selection of BBB models is believed to remarkably impact the data reliability leading to unsatisfactory results in clinical trials. In this review, we suggest a rationale for BBB model selection with respect to the addressed research question and downstream applications. The essential considerations of an optimal BBB model are discussed.
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Affiliation(s)
- Amira Sayed Hanafy
- Department of Pharmaceutics, Institute of Pharmacy, University of Bonn, Bonn, Germany; Department of Pharmaceutics and Pharmaceutical Technology, Faculty of Pharmacy, Pharos University in Alexandria, Alexandria, Egypt
| | - Dirk Dietrich
- Department of Neurosurgery, University Hospital Bonn, Bonn, Germany
| | - Gert Fricker
- Institute of Pharmacy and Molecular Biotechnology, Ruprecht-Karls University, Heidelberg, Germany
| | - Alf Lamprecht
- Department of Pharmaceutics, Institute of Pharmacy, University of Bonn, Bonn, Germany.
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195
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Ornelas S, Berthiaume AA, Bonney SK, Coelho-Santos V, Underly RG, Kremer A, Guérin CJ, Lippens S, Shih AY. Three-dimensional ultrastructure of the brain pericyte-endothelial interface. J Cereb Blood Flow Metab 2021; 41:2185-2200. [PMID: 33970018 PMCID: PMC8393306 DOI: 10.1177/0271678x211012836] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Pericytes and endothelial cells share membranous interdigitations called "peg-and-socket" interactions that facilitate their adhesion and biochemical crosstalk during vascular homeostasis. However, the morphology and distribution of these ultrastructures have remained elusive. Using a combination of 3D electron microscopy techniques, we examined peg-and-socket interactions in mouse brain capillaries. We found that pegs extending from pericytes to endothelial cells were morphologically diverse, exhibiting claw-like morphologies at the edge of the cell and bouton-shaped swellings away from the edge. Reciprocal endothelial pegs projecting into pericytes were less abundant and appeared as larger columnar protuberances. A large-scale 3D EM data set revealed enrichment of both pericyte and endothelial pegs around pericyte somata. The ratio of pericyte versus endothelial pegs was conserved among the pericytes examined, but total peg abundance was heterogeneous across cells. These data show considerable investment between pericytes and endothelial cells, and provide morphological evidence for pericyte somata as sites of enriched physical and biochemical interaction.
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Affiliation(s)
- Sharon Ornelas
- Center for Developmental Biology and Regenerative Medicine, Seattle Children’s Research Institute, Seattle, WA, USA
| | - Andrée-Anne Berthiaume
- Center for Developmental Biology and Regenerative Medicine, Seattle Children’s Research Institute, Seattle, WA, USA
- Department of Neuroscience, Medical University of South Carolina, Charleston, SC, USA
| | - Stephanie K Bonney
- Center for Developmental Biology and Regenerative Medicine, Seattle Children’s Research Institute, Seattle, WA, USA
| | - Vanessa Coelho-Santos
- Center for Developmental Biology and Regenerative Medicine, Seattle Children’s Research Institute, Seattle, WA, USA
| | - Robert G Underly
- Department of Neuroscience, Medical University of South Carolina, Charleston, SC, USA
| | - Anna Kremer
- VIB BioImaging Core, VIB, Ghent, Belgium
- VIB Inflammation Research Center, VIB, Ghent, Belgium
- Department of Biomedical Molecular Biology, Ghent University, Ghent, Belgium
| | - Christopher J Guérin
- VIB BioImaging Core, VIB, Ghent, Belgium
- VIB Inflammation Research Center, VIB, Ghent, Belgium
- Department of Biomedical Molecular Biology, Ghent University, Ghent, Belgium
| | - Saskia Lippens
- VIB BioImaging Core, VIB, Ghent, Belgium
- VIB Inflammation Research Center, VIB, Ghent, Belgium
- Department of Biomedical Molecular Biology, Ghent University, Ghent, Belgium
| | - Andy Y Shih
- Center for Developmental Biology and Regenerative Medicine, Seattle Children’s Research Institute, Seattle, WA, USA
- Department of Neuroscience, Medical University of South Carolina, Charleston, SC, USA
- Department of Pediatrics, University of Washington, Seattle, WA, USA
- Department of Bioengineering, University of Washington, Seattle, WA, USA
- Andy Y Shih, Center for Developmental Biology and Regenerative Medicine, Seattle Children’s Research Institute, 1900 9th Avenue M/S JMB.-5, Seattle, WA 98101, USA.
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196
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Pan SM, Pan Y, Tang YL, Zuo N, Zhang YX, Jia KK, Kong LD. Thioredoxin interacting protein drives astrocytic glucose hypometabolism in corticosterone-induced depressive state. J Neurochem 2021; 161:84-100. [PMID: 34368959 DOI: 10.1111/jnc.15489] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2021] [Revised: 07/30/2021] [Accepted: 08/04/2021] [Indexed: 01/18/2023]
Abstract
Brain energetics disturbance is a hypothesized cause of depression. Glucose is the predominant fuel of brain energy metabolism, however, the cell-specific change of glucose metabolism and underlying molecular mechanism in depression remain unclear. In this study, we firstly applied 18 F-FDG PET and observed brain glucose hypometabolism in prefrontal cortex (PFC) of corticosterone-induced depression of rats. Next, astrocytic glucose hypometabolism was identified in PFC slices in in both corticosterone-induced depression of rats and cultured primary astrocytes from newborn rat PFC after stress-level corticosterone (100 nM) stimulation. Furthermore, we found the blockage of glucose uptake and the decrease of plasma membrane (PM) translocation of glucose transporter 1 (GLUT1) in astrocytic glucose hypometabolism under depressive condition. Interestingly, thioredoxin interacting protein (TXNIP), a glucose metabolism sensor and controller, was found to be overexpressed in corticosterone-stimulated astrocytes in vivo and in vitro. High TXNIP level could restrict GLUT1-mediated glucose uptake in primary astrocytes in vitro. Adeno-associated virus vector-mediated astrocytic TXNIP overexpression in rat medial PFC suppressed GLUT1 PM translocation, consequently developed depressive-like behavior. Conversely, TXNIP siRNA facilitated GLUT1 PM translocation to recover glucose hypometabolism in corticosterone-exposed cultured astrocytes. Notably, astrocyte-specific knockdown of TXNIP in medial PFC of rats facilitated astrocytic GLUT1 PM translocation, showing obvious antidepressant activity. These findings provide a new astrocytic energetic perspective in the pathogenesis of depression, more importantly, provide TXNIP as a promising molecular target for novel depression therapy.
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Affiliation(s)
- Shu-Man Pan
- State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing, 210023, Jiangsu Province, P. R. China
| | - Ying Pan
- State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing, 210023, Jiangsu Province, P. R. China
| | - Ya-Li Tang
- State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing, 210023, Jiangsu Province, P. R. China
| | - Na Zuo
- State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing, 210023, Jiangsu Province, P. R. China
| | - Yan-Xiu Zhang
- State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing, 210023, Jiangsu Province, P. R. China
| | - Ke-Ke Jia
- State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing, 210023, Jiangsu Province, P. R. China
| | - Ling-Dong Kong
- State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing, 210023, Jiangsu Province, P. R. China
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197
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Martinac AD, Fletcher DF, Bilston LE. Phase offset between arterial pulsations and subarachnoid space pressure fluctuations are unlikely to drive periarterial cerebrospinal fluid flow. Biomech Model Mechanobiol 2021; 20:1751-1766. [PMID: 34275063 DOI: 10.1007/s10237-021-01474-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Accepted: 06/02/2021] [Indexed: 11/24/2022]
Abstract
Circulation of fluid through the central nervous system maintains fluid homeostasis and is involved in solute clearance. The glymphatic system is hypothesised to facilitate waste clearance in the brain, with inflow via periarterial spaces, bulk flow through the parenchyma, and outflow via perivenous spaces. The driving force for this mechanism is unknown. Previous modelling in the spinal cord suggests that timing offsets between arterial and subarachnoid space pressure pulses can enable net inflow in perivascular spaces (PVS). This study adapted the spinal pulse offset mechanism to the brain and simulated movement of tracer particles used in experiments. Both bulk flow and diffusive movement of tracer were simulated. Intracranial pressure pulses were applied to one end of a 300-μm-long perivascular space combined with a moving arterial wall simulating arterial pulsations. The simulations indicate the pulse offset mechanism can enable net inflow via PVS; however, it is unknown whether the temporal offset required is physiologically realistic. Increasing the positive component of the ICP (intracranial pressure) pulse increased net flow. Tracer particles driven by bulk flow reached the outlet of the PVS with a net speed of ~ 16 μm/s when the permeability was two orders of magnitude higher than values in the literature. These particles were unable to penetrate into the parenchyma in the absence of diffusion. Dispersion dominated tracer movement in the parenchyma. Further research is required to reconcile discrepancies between these results, and both experimental and computational studies.
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Affiliation(s)
- Adam D Martinac
- Neuroscience Research Australia and Prince of Wales Clinical School, UNSW, Kensington, Australia.
| | - David F Fletcher
- School of Chemical and Biomolecular Engineering, The University of Sydney, Camperdown, Australia
| | - Lynne E Bilston
- Neuroscience Research Australia and Prince of Wales Clinical School, UNSW, Kensington, Australia
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198
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Abdellah M, Foni A, Zisis E, Guerrero NR, Lapere S, Coggan JS, Keller D, Markram H, Schürmann F. Metaball skinning of synthetic astroglial morphologies into realistic mesh models for visual analytics and in silico simulations. Bioinformatics 2021; 37:i426-i433. [PMID: 34252950 PMCID: PMC8275327 DOI: 10.1093/bioinformatics/btab280] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Motivation Astrocytes, the most abundant glial cells in the mammalian brain, have an instrumental role in developing neuronal circuits. They contribute to the physical structuring of the brain, modulating synaptic activity and maintaining the blood–brain barrier in addition to other significant aspects that impact brain function. Biophysically, detailed astrocytic models are key to unraveling their functional mechanisms via molecular simulations at microscopic scales. Detailed, and complete, biological reconstructions of astrocytic cells are sparse. Nonetheless, data-driven digital reconstruction of astroglial morphologies that are statistically identical to biological counterparts are becoming available. We use those synthetic morphologies to generate astrocytic meshes with realistic geometries, making it possible to perform these simulations. Results We present an unconditionally robust method capable of reconstructing high fidelity polygonal meshes of astroglial cells from algorithmically-synthesized morphologies. Our method uses implicit surfaces, or metaballs, to skin the different structural components of astrocytes and then blend them in a seamless fashion. We also provide an end-to-end pipeline to produce optimized two- and three-dimensional meshes for visual analytics and simulations, respectively. The performance of our pipeline has been assessed with a group of 5000 astroglial morphologies and the geometric metrics of the resulting meshes are evaluated. The usability of the meshes is then demonstrated with different use cases. Availability and implementation Our metaball skinning algorithm is implemented in Blender 2.82 relying on its Python API (Application Programming Interface). To make it accessible to computational biologists and neuroscientists, the implementation has been integrated into NeuroMorphoVis, an open source and domain specific package that is primarily designed for neuronal morphology visualization and meshing. Supplementary information Supplementary data are available at Bioinformatics online.
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Affiliation(s)
- Marwan Abdellah
- Blue Brain Project (BBP), École polytechnique fédérale de Lausanne (EPFL), Geneva 1202, Switzerland
| | - Alessandro Foni
- Blue Brain Project (BBP), École polytechnique fédérale de Lausanne (EPFL), Geneva 1202, Switzerland
| | - Eleftherios Zisis
- Blue Brain Project (BBP), École polytechnique fédérale de Lausanne (EPFL), Geneva 1202, Switzerland
| | - Nadir Román Guerrero
- Blue Brain Project (BBP), École polytechnique fédérale de Lausanne (EPFL), Geneva 1202, Switzerland
| | - Samuel Lapere
- Blue Brain Project (BBP), École polytechnique fédérale de Lausanne (EPFL), Geneva 1202, Switzerland
| | - Jay S Coggan
- Blue Brain Project (BBP), École polytechnique fédérale de Lausanne (EPFL), Geneva 1202, Switzerland
| | - Daniel Keller
- Blue Brain Project (BBP), École polytechnique fédérale de Lausanne (EPFL), Geneva 1202, Switzerland
| | - Henry Markram
- Blue Brain Project (BBP), École polytechnique fédérale de Lausanne (EPFL), Geneva 1202, Switzerland
| | - Felix Schürmann
- Blue Brain Project (BBP), École polytechnique fédérale de Lausanne (EPFL), Geneva 1202, Switzerland
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199
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Stackhouse TL, Mishra A. Neurovascular Coupling in Development and Disease: Focus on Astrocytes. Front Cell Dev Biol 2021; 9:702832. [PMID: 34327206 PMCID: PMC8313501 DOI: 10.3389/fcell.2021.702832] [Citation(s) in RCA: 49] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Accepted: 06/09/2021] [Indexed: 12/14/2022] Open
Abstract
Neurovascular coupling is a crucial mechanism that matches the high energy demand of the brain with a supply of energy substrates from the blood. Signaling within the neurovascular unit is responsible for activity-dependent changes in cerebral blood flow. The strength and reliability of neurovascular coupling form the basis of non-invasive human neuroimaging techniques, including blood oxygen level dependent (BOLD) functional magnetic resonance imaging. Interestingly, BOLD signals are negative in infants, indicating a mismatch between metabolism and blood flow upon neural activation; this response is the opposite of that observed in healthy adults where activity evokes a large oversupply of blood flow. Negative neurovascular coupling has also been observed in rodents at early postnatal stages, further implying that this is a process that matures during development. This rationale is consistent with the morphological maturation of the neurovascular unit, which occurs over a similar time frame. While neurons differentiate before birth, astrocytes differentiate postnatally in rodents and the maturation of their complex morphology during the first few weeks of life links them with synapses and the vasculature. The vascular network is also incomplete in neonates and matures in parallel with astrocytes. Here, we review the timeline of the structural maturation of the neurovascular unit with special emphasis on astrocytes and the vascular tree and what it implies for functional maturation of neurovascular coupling. We also discuss similarities between immature astrocytes during development and reactive astrocytes in disease, which are relevant to neurovascular coupling. Finally, we close by pointing out current gaps in knowledge that must be addressed to fully elucidate the mechanisms underlying neurovascular coupling maturation, with the expectation that this may also clarify astrocyte-dependent mechanisms of cerebrovascular impairment in neurodegenerative conditions in which reduced or negative neurovascular coupling is noted, such as stroke and Alzheimer’s disease.
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Affiliation(s)
- Teresa L Stackhouse
- Department of Neurology, Jungers Center for Neurosciences Research, Oregon Health & Science University, Portland, OR, United States
| | - Anusha Mishra
- Department of Neurology, Jungers Center for Neurosciences Research, Oregon Health & Science University, Portland, OR, United States.,Knight Cardiovascular Institute, Oregon Health & Sciences University, Portland, OR, United States
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200
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Lv T, Zhao B, Hu Q, Zhang X. The Glymphatic System: A Novel Therapeutic Target for Stroke Treatment. Front Aging Neurosci 2021; 13:689098. [PMID: 34305569 PMCID: PMC8297504 DOI: 10.3389/fnagi.2021.689098] [Citation(s) in RCA: 37] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Accepted: 06/07/2021] [Indexed: 12/25/2022] Open
Abstract
The glymphatic system (GS) is a novel defined brain-wide perivascular transit network between cerebrospinal fluid (CSF) and interstitial solutes that facilitates the clearance of brain metabolic wastes. The complicated network of the GS consists of the periarterial CSF influx pathway, astrocytes-mediated convective transport of fluid and solutes supported by AQP4 water channels, and perivenous efflux pathway. Recent researches indicate that the GS dysfunction is associated with various neurological disorders, including traumatic brain injury, hydrocephalus, epilepsy, migraine, and Alzheimer’s disease (AD). Meanwhile, the GS also plays a pivotal role in the pathophysiological process of stroke, including brain edema, blood–brain barrier (BBB) disruption, immune cell infiltration, neuroinflammation, and neuronal apoptosis. In this review, we illustrated the key anatomical structures of the GS, the relationship between the GS and the meningeal lymphatic system, the interaction between the GS and the BBB, and the crosstalk between astrocytes and other GS cellular components. In addition, we contributed to the current knowledge about the role of the GS in the pathology of stroke and the role of AQP4 in stroke. We further discussed the potential use of the GS in early risk assessment, diagnostics, prognostics, and therapeutics of stroke.
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Affiliation(s)
- Tao Lv
- Department of Neurosurgery, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Bing Zhao
- Department of Neurosurgery, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Qin Hu
- Central Laboratory, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Xiaohua Zhang
- Department of Neurosurgery, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
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