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Vara-Pérez M, Movahedi K. Border-associated macrophages as gatekeepers of brain homeostasis and immunity. Immunity 2025; 58:1085-1100. [PMID: 40324381 PMCID: PMC12094687 DOI: 10.1016/j.immuni.2025.04.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2025] [Revised: 03/26/2025] [Accepted: 04/07/2025] [Indexed: 05/07/2025]
Abstract
The brain's border tissues serve as essential hubs for neuroimmune regulation and the trafficking of biomaterials to and from the brain. These complex tissues-including the meninges, perivascular spaces, choroid plexus, and circumventricular organs-balance the brain's need for immune privilege with immune surveillance and blood-brain communication. Macrophages are integral components of these tissues, taking up key strategic positions within the brain's circulatory system. These border-associated macrophages, or "BAMs," are therefore emerging as pivotal for brain homeostasis and disease. BAMs perform trophic functions that help to support border homeostasis but also act as immune sentinels essential for border defense. In this review, we integrate recent findings on BAM origins, cell states, and functions, aiming to provide global insights and perspectives on the complex relationship between these macrophages and their border niche.
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Affiliation(s)
- Mónica Vara-Pérez
- Brain and Systems Immunology Laboratory, Brussels Center for Immunology, Vrije Universiteit Brussel, Brussels, Belgium
| | - Kiavash Movahedi
- Brain and Systems Immunology Laboratory, Brussels Center for Immunology, Vrije Universiteit Brussel, Brussels, Belgium.
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2
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Asimakidou E, Saipuljumri EN, Lo CH, Zeng J. Role of metabolic dysfunction and inflammation along the liver-brain axis in animal models with obesity-induced neurodegeneration. Neural Regen Res 2025; 20:1069-1076. [PMID: 38989938 PMCID: PMC11438328 DOI: 10.4103/nrr.nrr-d-23-01770] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2023] [Accepted: 04/26/2024] [Indexed: 07/12/2024] Open
Abstract
The interaction between metabolic dysfunction and inflammation is central to the development of neurodegenerative diseases such as Alzheimer's disease and Parkinson's disease. Obesity-related conditions like type 2 diabetes and non-alcoholic fatty liver disease exacerbate this relationship. Peripheral lipid accumulation, particularly in the liver, initiates a cascade of inflammatory processes that extend to the brain, influencing critical metabolic regulatory regions. Ceramide and palmitate, key lipid components, along with lipid transporters lipocalin-2 and apolipoprotein E, contribute to neuroinflammation by disrupting blood-brain barrier integrity and promoting gliosis. Peripheral insulin resistance further exacerbates brain insulin resistance and neuroinflammation. Preclinical interventions targeting peripheral lipid metabolism and insulin signaling pathways have shown promise in reducing neuroinflammation in animal models. However, translating these findings to clinical practice requires further investigation into human subjects. In conclusion, metabolic dysfunction, peripheral inflammation, and insulin resistance are integral to neuroinflammation and neurodegeneration. Understanding these complex mechanisms holds potential for identifying novel therapeutic targets and improving outcomes for neurodegenerative diseases.
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Affiliation(s)
- Evridiki Asimakidou
- Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK
| | - Eka Norfaishanty Saipuljumri
- School of Applied Science, Republic Polytechnic, Singapore, Singapore
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, Singapore
| | - Chih Hung Lo
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, Singapore
| | - Jialiu Zeng
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, Singapore
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3
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Savulescu-Fiedler I, Dorobantu-Lungu LR, Dragosloveanu S, Benea SN, Dragosloveanu CDM, Caruntu A, Scheau AE, Caruntu C, Scheau C. The Cross-Talk Between the Peripheral and Brain Cholesterol Metabolisms. Curr Issues Mol Biol 2025; 47:115. [PMID: 39996836 PMCID: PMC11853762 DOI: 10.3390/cimb47020115] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2024] [Revised: 01/30/2025] [Accepted: 02/07/2025] [Indexed: 02/26/2025] Open
Abstract
Cholesterol is an essential element for the development and normal function of the central nervous system. While peripheral cholesterol is influenced by liver metabolism and diet, brain cholesterol metabolism takes place in an isolated system due to the impermeability of the blood-brain barrier (BBB). However, cross-talk occurs between the brain and periphery, specifically through metabolites such as oxysterols that play key roles in regulating cholesterol balance. Several neurodegenerative conditions such as Alzheimer's disease or Parkinson's disease are considered to be affected by the loss of this balance. Also, the treatment of hypercholesterolemia needs to consider these discrete interferences between brain and peripheral cholesterol and the possible implications of each therapeutic approach. This is particularly important because of 27-hydroxycholesterol and 24-hydroxycholesterol, which can cross the BBB and are involved in cholesterol metabolism. This paper examines the metabolic pathways of cholesterol metabolism in the brain and periphery and focuses on the complex cross-talk between these metabolisms. Also, we emphasize the regulatory role of the BBB and the need for an integrated approach to cholesterol management.
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Affiliation(s)
- Ilinca Savulescu-Fiedler
- Department of Internal Medicine, The “Carol Davila” University of Medicine and Pharmacy, 050474 Bucharest, Romania
- Department of Internal Medicine and Cardiology, Coltea Clinical Hospital, 030167 Bucharest, Romania
| | - Luiza-Roxana Dorobantu-Lungu
- Department of Cardiology, Emergency Institute for Cardiovascular Diseases “C.C. Iliescu”, 022328 Bucharest, Romania
| | - Serban Dragosloveanu
- Department of Orthopaedics, “Foisor” Clinical Hospital of Orthopaedics, Traumatology and Osteoarticular TB, 021382 Bucharest, Romania
- Department of Orthopaedics and Traumatology, The “Carol Davila” University of Medicine and Pharmacy, 050474 Bucharest, Romania
| | - Serban Nicolae Benea
- Department of Infectious Diseases, The “Carol Davila” University of Medicine and Pharmacy, 050474 Bucharest, Romania
- Departament of Infectious Diseases, National Institute for Infectious Diseases “Prof. Dr. Matei Balș”, 021105 Bucharest, Romania
| | - Christiana Diana Maria Dragosloveanu
- Department of Ophthalmology, Faculty of Dentistry, The “Carol Davila” University of Medicine and Pharmacy, 050474 Bucharest, Romania
- Department of Ophthalmology, Clinical Hospital for Ophthalmological Emergencies, 010464 Bucharest, Romania
| | - Ana Caruntu
- Department of Oral and Maxillofacial Surgery, “Carol Davila” Central Military Emergency Hospital, 010825 Bucharest, Romania
- Department of Oral and Maxillofacial Surgery, Faculty of Dental Medicine, “Titu Maiorescu” University, 031593 Bucharest, Romania
| | - Andreea-Elena Scheau
- Department of Radiology and Medical Imaging, Fundeni Clinical Institute, 022328 Bucharest, Romania
| | - Constantin Caruntu
- Department of Physiology, The “Carol Davila” University of Medicine and Pharmacy, 050474 Bucharest, Romania
- Department of Dermatology, “Prof. N.C. Paulescu” National Institute of Diabetes, Nutrition and Metabolic Diseases, 011233 Bucharest, Romania
| | - Cristian Scheau
- Department of Physiology, The “Carol Davila” University of Medicine and Pharmacy, 050474 Bucharest, Romania
- Department of Radiology and Medical Imaging, “Foisor” Clinical Hospital of Orthopaedics, Traumatology and Osteoarticular TB, 021382 Bucharest, Romania
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Kovacs M, Dominguez-Belloso A, Ali-Moussa S, Deczkowska A. Immune control of brain physiology. Nat Rev Immunol 2025:10.1038/s41577-025-01129-6. [PMID: 39890999 DOI: 10.1038/s41577-025-01129-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/02/2025] [Indexed: 02/03/2025]
Abstract
The peripheral immune system communicates with the brain through complex anatomical routes involving the skull, the brain borders, circumventricular organs and peripheral nerves. These immune-brain communication pathways were classically considered to be dormant under physiological conditions and active only in cases of infection or damage. Yet, peripheral immune cells and signals are key in brain development, function and maintenance. In this Perspective, we propose an alternative framework for understanding the mechanisms of immune-brain communication. During brain development and in homeostasis, these anatomical structures allow selected elements of the peripheral immune system to affect the brain directly or indirectly, within physiological limits. By contrast, in ageing and pathological settings, detrimental peripheral immune signals hijack the existing communication routes or alter their structure. We discuss why a diversity of communication channels is needed and how they work in relation to one another to maintain homeostasis of the brain.
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Affiliation(s)
- Mariángeles Kovacs
- Brain-Immune Communication Lab, Institut Pasteur, Université Paris Cité, Inserm U1224, Paris, France
| | - Amaia Dominguez-Belloso
- Brain-Immune Communication Lab, Institut Pasteur, Université Paris Cité, Inserm U1224, Paris, France
| | - Samir Ali-Moussa
- Brain-Immune Communication Lab, Institut Pasteur, Université Paris Cité, Inserm U1224, Paris, France
| | - Aleksandra Deczkowska
- Brain-Immune Communication Lab, Institut Pasteur, Université Paris Cité, Inserm U1224, Paris, France.
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Fujii R, Nambu Y, Sawant Shirikant N, Furube E, Morita M, Yoshimura R, Miyata S. Neuronal regeneration in the area postrema of adult mouse medulla oblongata following glutamate-induced neuronal elimination. Neuroscience 2024; 563:188-201. [PMID: 39521321 DOI: 10.1016/j.neuroscience.2024.11.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2023] [Revised: 11/02/2024] [Accepted: 11/04/2024] [Indexed: 11/16/2024]
Abstract
Neural stem cells and/or progenitor cells (NSCs/NPCs) in the subventricular and subgranular zones of the adult mammal forebrain generate new neurons and are involved in partial repair after injury. Recently, NSCs/NPCs were identified in the area postrema (AP) of the medulla oblongata of the hindbrain. In this study, we used the properties of fenestrate capillaries to observe specific neuronal elimination in the AP of adult mice and investigated subsequent neuronal regeneration by neurogenesis. Subcutaneous administration of monosodium glutamate (MSG) induced prominent Fos expression in HuC/D+ neurons in the AP 2 h after administration. MSG administration caused a marked decrease in HuC/D+ neuronal density by neuronal death 3 to 21 days after administration, which recovered to the control level 35 days later. After MSG administration, the density of TUNEL+ dying neurons and phagocytic microglia surrounding or engulfing neurons increased. Within 7 days of MSG administration, the number of BrdU+ Sox2+ and BrdU+ Math1+ cells increased markedly, and at least the BrdU+ Math1+ cells similarly increased for the next following 7 days. A remarkable number of HuC/D+ neurons with BrdU+ nuclei were observed 35 days after MSG administration. This study reveals that neurogenesis occurs in the AP of adult mice, recovering and maintaining normal neuronal density after neuronal death.
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Affiliation(s)
- Rena Fujii
- Department of Applied Biology, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 606-8585, Japan
| | - Yuri Nambu
- Department of Applied Biology, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 606-8585, Japan
| | - Nitin Sawant Shirikant
- Department of Biology, Graduate School of Science, Kobe University, Kobe 657-8501, Japan
| | - Eriko Furube
- Department of Applied Biology, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 606-8585, Japan; Department of Anatomy, Asahikawa Medical University School of Medicine, Midorigaoka, Asahikawa, Hokkaido 078-8510, Japan
| | - Mitsuhiro Morita
- Department of Biology, Graduate School of Science, Kobe University, Kobe 657-8501, Japan
| | - Ryoichi Yoshimura
- Department of Applied Biology, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 606-8585, Japan
| | - Seiji Miyata
- Department of Applied Biology, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 606-8585, Japan.
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Jurcau MC, Jurcau A, Cristian A, Hogea VO, Diaconu RG, Nunkoo VS. Inflammaging and Brain Aging. Int J Mol Sci 2024; 25:10535. [PMID: 39408862 PMCID: PMC11476611 DOI: 10.3390/ijms251910535] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2024] [Revised: 09/25/2024] [Accepted: 09/26/2024] [Indexed: 10/20/2024] Open
Abstract
Progress made by the medical community in increasing lifespans comes with the costs of increasing the incidence and prevalence of age-related diseases, neurodegenerative ones included. Aging is associated with a series of morphological changes at the tissue and cellular levels in the brain, as well as impairments in signaling pathways and gene transcription, which lead to synaptic dysfunction and cognitive decline. Although we are not able to pinpoint the exact differences between healthy aging and neurodegeneration, research increasingly highlights the involvement of neuroinflammation and chronic systemic inflammation (inflammaging) in the development of age-associated impairments via a series of pathogenic cascades, triggered by dysfunctions of the circadian clock, gut dysbiosis, immunosenescence, or impaired cholinergic signaling. In addition, gender differences in the susceptibility and course of neurodegeneration that appear to be mediated by glial cells emphasize the need for future research in this area and an individualized therapeutic approach. Although rejuvenation research is still in its very early infancy, accumulated knowledge on the various signaling pathways involved in promoting cellular senescence opens the perspective of interfering with these pathways and preventing or delaying senescence.
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Affiliation(s)
| | - Anamaria Jurcau
- Department of Psycho-Neurosciences and Rehabilitation, University of Oradea, 410087 Oradea, Romania
| | - Alexander Cristian
- Department of Psycho-Neurosciences and Rehabilitation, University of Oradea, 410087 Oradea, Romania
| | - Vlad Octavian Hogea
- Faculty of Medicine and Pharmacy, University of Oradea, 410087 Oradea, Romania
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Yao Y, Chen Y, Tomer R, Silver R. Capillary connections between sensory circumventricular organs and adjacent parenchyma enable local volume transmission. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.07.30.605849. [PMID: 39211092 PMCID: PMC11361043 DOI: 10.1101/2024.07.30.605849] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/04/2024]
Abstract
Among contributors to diffusible signaling are portal systems which join two capillary beds through connecting veins (Dorland 2020). Portal systems allow diffusible signals to be transported in high concentrations directly from one capillary bed to the other without dilution in the systemic circulation. Two portal systems have been identified in the brain. The first was discovered almost a century ago and connects the median eminence to the anterior pituitary gland (Popa & Fielding 1930). The second was discovered a few years ago, and links the suprachiasmatic nucleus to the organum vasculosum of the lamina terminalis, a sensory circumventricular organ (CVO) (Yao et al. 2021). Sensory CVOs bear neuronal receptors for sensing signals in the fluid milieu (McKinley et al. 2003). They line the surface of brain ventricles and bear fenestrated capillaries, thereby lacking blood brain barriers. It is not known whether the other sensory CVOs, namely the subfornical organ (SFO), and area postrema (AP) form portal neurovascular connections with nearby parenchymal tissue. This has been difficult to establish as the structures lie at the midline and protrude into the ventricular space. To preserve the integrity of the vasculature of CVOs and their adjacent neuropil, we combined iDISCO clearing and light-sheet microscopy to acquire volumetric images of blood vessels. The results indicate that there is a portal pathway linking the capillary vessels of the SFO and the posterior septal nuclei, namely the septofimbrial nucleus and the triangular nucleus of the septum. Unlike the latter arrangement, the AP and the nucleus of the solitary tract share their capillary beds. Taken together, the results reveal that all three sensory circumventricular organs bear specialized capillary connections to adjacent neuropil, providing a direct route for diffusible signals to travel from their source to their targets.
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Lau K, Kotzur R, Richter F. Blood-brain barrier alterations and their impact on Parkinson's disease pathogenesis and therapy. Transl Neurodegener 2024; 13:37. [PMID: 39075566 PMCID: PMC11285262 DOI: 10.1186/s40035-024-00430-z] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2024] [Accepted: 07/11/2024] [Indexed: 07/31/2024] Open
Abstract
There is increasing evidence for blood-brain barrier (BBB) alterations in Parkinson's disease (PD), the second most common neurodegenerative disorder with rapidly rising prevalence. Altered tight junction and transporter protein levels, accumulation of α-synuclein and increase in inflammatory processes lead to extravasation of blood molecules and vessel degeneration. This could result in a self-perpetuating pathophysiology of inflammation and BBB alteration, which contribute to neurodegeneration. Toxin exposure or α-synuclein over-expression in animal models has been shown to initiate similar pathologies, providing a platform to study underlying mechanisms and therapeutic interventions. Here we provide a comprehensive review of the current knowledge on BBB alterations in PD patients and how rodent models that replicate some of these changes can be used to study disease mechanisms. Specific challenges in assessing the BBB in patients and in healthy controls are discussed. Finally, a potential role of BBB alterations in disease pathogenesis and possible implications for therapy are explored. The interference of BBB alterations with current and novel therapeutic strategies requires more attention. Brain region-specific BBB alterations could also open up novel opportunities to target specifically vulnerable neuronal subpopulations.
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Affiliation(s)
- Kristina Lau
- Department of Pharmacology, Toxicology and Pharmacy, University of Veterinary Medicine Hannover, Foundation, Bünteweg 17, 30559, Hannover, Germany
- Center for Systems Neuroscience, Hannover, Germany
| | - Rebecca Kotzur
- Department of Pharmacology, Toxicology and Pharmacy, University of Veterinary Medicine Hannover, Foundation, Bünteweg 17, 30559, Hannover, Germany
| | - Franziska Richter
- Department of Pharmacology, Toxicology and Pharmacy, University of Veterinary Medicine Hannover, Foundation, Bünteweg 17, 30559, Hannover, Germany.
- Center for Systems Neuroscience, Hannover, Germany.
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Yang R, Yan F, Shen J, Wang T, Li M, Ni H. Geraniol attenuates oxygen-glucose deprivation/reoxygenation-induced ROS-dependent apoptosis and permeability of human brain microvascular endothelial cells by activating the Nrf-2/HO-1 pathway. J Bioenerg Biomembr 2024; 56:193-204. [PMID: 38446318 DOI: 10.1007/s10863-024-10011-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2023] [Accepted: 03/01/2024] [Indexed: 03/07/2024]
Abstract
Blood-brain barrier breakdown and ROS overproduction are important events during the progression of ischemic stroke aggravating brain damage. Geraniol, a natural monoterpenoid, possesses anti-apoptotic, cytoprotective, anti-oxidant, and anti-inflammatory activities. Our study aimed to investigate the effect and underlying mechanisms of geraniol in oxygen-glucose deprivation/reoxygenation (OGD/R)-induced human brain microvascular endothelial cells (HBMECs). Apoptosis, caspase-3 activity, and cytotoxicity of HBMECs were evaluated using TUNEL, caspase-3 activity, and CCK-8 assays, respectively. The permeability of HBMECs was examined using FITC-dextran assay. Reactive oxygen species (ROS) production was measured using the fluorescent probe DCFH-DA. The protein levels of zonula occludens-1 (ZO-1), occludin, claudin-5, β-catenin, nuclear factor erythroid 2-related factor 2 (Nrf2), and heme oxygenase-1 (HO-1) were determined by western blotting. Geraniol showed no cytotoxicity in HBMECs. Geraniol and ROS scavenger N-acetylcysteine (NAC) both attenuated OGD/R-induced apoptosis and increase of caspase-3 activity and the permeability to FITC-dextran in HBMECs. Geraniol relieved OGD/R-induced ROS accumulation and decrease of expression of ZO-1, occludin, claudin-5, and β-catenin in HBMECs. Furthermore, we found that geraniol activated Nrf2/HO-1 pathway to inhibit ROS in HBMECs. In conclusion, geraniol attenuated OGD/R-induced ROS-dependent apoptosis and permeability in HBMECs through activating the Nrf2/HO-1 pathway.
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Affiliation(s)
- Ronggang Yang
- Department of Neurological Intensive Resuscitation, Nanshi Hospital of Nanyang, Nanyang, 473000, China
| | - Feng Yan
- Department of Neurological Intensive Resuscitation, Nanshi Hospital of Nanyang, Nanyang, 473000, China
| | - Jiangyi Shen
- Department of Critical Care Medicine, Nanshi Hospital of Nanyang, Nanyang, 473000, China
| | - Tiancai Wang
- Department of Critical Care Medicine, Nanshi Hospital of Nanyang, Nanyang, 473000, China
| | - Menglong Li
- Department of Critical Care Medicine, Nanshi Hospital of Nanyang, Nanyang, 473000, China
| | - Hongzao Ni
- Department of Neurosurgery, Huai'an Second People's Hospital, the Affiliated Huai'an Hospital of Xuzhou Medical University, Huai'an, 223300, China.
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Morsy SAA, Fathelbab MH, El-Sayed NS, El-Habashy SE, Aly RG, Harby SA. Doxycycline-Loaded Calcium Phosphate Nanoparticles with a Pectin Coat Can Ameliorate Lipopolysaccharide-Induced Neuroinflammation Via Enhancing AMPK. J Neuroimmune Pharmacol 2024; 19:2. [PMID: 38236457 PMCID: PMC10796490 DOI: 10.1007/s11481-024-10099-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2023] [Accepted: 12/06/2023] [Indexed: 01/19/2024]
Abstract
Neuroinflammation occurs in response to different injurious triggers to limit their hazardous effects. However, failure to stop this process can end in multiple neurological diseases. Doxycycline (DX) is a tetracycline, with potential antioxidant and anti-inflammatory properties. The current study tested the effects of free DX, DX-loaded calcium phosphate (DX@CaP), and pectin-coated DX@CaP (Pec/DX@CaP) nanoparticles on the lipopolysaccharide (LPS)-induced neuroinflammation in mice and to identify the role of adenosine monophosphate-activated protein kinase (AMPK) in this effect. The present study was conducted on 48 mice, divided into 6 groups, eight mice each. Group 1 (normal control), Group 2 (blank nanoparticles-treated), Group 3 (LPS (untreated)), Groups 4, 5, and 6 received LPS, then Group 4 received free DX, Group 5 received DX-loaded calcium phosphate nanoparticles (DX@CaP), and Group 6 received DX-loaded calcium phosphate nanoparticles with a pectin coat (Pec/DX@CaP). At the end of the experimentation period, behavioral tests were carried out. Then, mice were sacrificed, and brain tissue was extracted and used for histological examination, and assessment of interleukin-6 positive cells in different brain areas, in addition to biochemical measurement of SOD activity, TLR-4, AMPK and Nrf2. LPS can induce prominent neuroinflammation. Treatment with (Pec/DX@CaP) can reverse most behavioral, histopathological, and biochemical changes caused by LPS. The findings of the current study suggest that (Pec/DX@CaP) exerts a significant reverse of LPS-induced neuroinflammation by enhancing SOD activity, AMPK, and Nrf2 expression, in addition to suppression of TLR-4.
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Affiliation(s)
| | - Mona Hassan Fathelbab
- Medical Biochemistry Department, Faculty of Medicine, Alexandria University, Alexandria, Egypt
| | - Norhan S El-Sayed
- Medical Physiology Department, Faculty of Medicine, Alexandria University, Alexandria, Egypt
| | - Salma E El-Habashy
- Department of Pharmaceutics, Faculty of Pharmacy, Alexandria University, Alexandria, Egypt
| | - Rania G Aly
- Pathology Department, Faculty of Medicine, Alexandria University, Alexandria, Egypt
| | - Sahar A Harby
- Clinical Pharmacology Department, Faculty of Medicine, Alexandria University, Alexandria, Egypt.
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11
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Aspden JW, Murphy MA, Kashlan RD, Xiong Y, Poznansky MC, Sîrbulescu RF. Intruders or protectors - the multifaceted role of B cells in CNS disorders. Front Cell Neurosci 2024; 17:1329823. [PMID: 38269112 PMCID: PMC10806081 DOI: 10.3389/fncel.2023.1329823] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2023] [Accepted: 12/20/2023] [Indexed: 01/26/2024] Open
Abstract
B lymphocytes are immune cells studied predominantly in the context of peripheral humoral immune responses against pathogens. Evidence has been accumulating in recent years on the diversity of immunomodulatory functions that B cells undertake, with particular relevance for pathologies of the central nervous system (CNS). This review summarizes current knowledge on B cell populations, localization, infiltration mechanisms, and function in the CNS and associated tissues. Acute and chronic neurodegenerative pathologies are examined in order to explore the complex, and sometimes conflicting, effects that B cells can have in each context, with implications for disease progression and treatment outcomes. Additional factors such as aging modulate the proportions and function of B cell subpopulations over time and are also discussed in the context of neuroinflammatory response and disease susceptibility. A better understanding of the multifactorial role of B cell populations in the CNS may ultimately lead to innovative therapeutic strategies for a variety of neurological conditions.
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Affiliation(s)
- James W. Aspden
- Vaccine and Immunotherapy Center, Massachusetts General Hospital and Harvard Medical School, Boston, MA, United States
| | - Matthew A. Murphy
- Vaccine and Immunotherapy Center, Massachusetts General Hospital and Harvard Medical School, Boston, MA, United States
| | - Rommi D. Kashlan
- Vaccine and Immunotherapy Center, Massachusetts General Hospital and Harvard Medical School, Boston, MA, United States
| | - Yueyue Xiong
- Vaccine and Immunotherapy Center, Massachusetts General Hospital and Harvard Medical School, Boston, MA, United States
| | - Mark C. Poznansky
- Vaccine and Immunotherapy Center, Massachusetts General Hospital and Harvard Medical School, Boston, MA, United States
| | - Ruxandra F. Sîrbulescu
- Vaccine and Immunotherapy Center, Massachusetts General Hospital and Harvard Medical School, Boston, MA, United States
- Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, United States
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12
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Wevers NR, De Vries HE. Microfluidic models of the neurovascular unit: a translational view. Fluids Barriers CNS 2023; 20:86. [PMID: 38008744 PMCID: PMC10680291 DOI: 10.1186/s12987-023-00490-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2023] [Accepted: 11/15/2023] [Indexed: 11/28/2023] Open
Abstract
The vasculature of the brain consists of specialized endothelial cells that form a blood-brain barrier (BBB). This barrier, in conjunction with supporting cell types, forms the neurovascular unit (NVU). The NVU restricts the passage of certain substances from the bloodstream while selectively permitting essential nutrients and molecules to enter the brain. This protective role is crucial for optimal brain function, but presents a significant obstacle in treating neurological conditions, necessitating chemical modifications or advanced drug delivery methods for most drugs to cross the NVU. A deeper understanding of NVU in health and disease will aid in the identification of new therapeutic targets and drug delivery strategies for improved treatment of neurological disorders.To achieve this goal, we need models that reflect the human BBB and NVU in health and disease. Although animal models of the brain's vasculature have proven valuable, they are often of limited translational relevance due to interspecies differences or inability to faithfully mimic human disease conditions. For this reason, human in vitro models are essential to improve our understanding of the brain's vasculature under healthy and diseased conditions. This review delves into the advancements in in vitro modeling of the BBB and NVU, with a particular focus on microfluidic models. After providing a historical overview of the field, we shift our focus to recent developments, offering insights into the latest achievements and their associated constraints. We briefly examine the importance of chip materials and methods to facilitate fluid flow, emphasizing their critical roles in achieving the necessary throughput for the integration of microfluidic models into routine experimentation. Subsequently, we highlight the recent strides made in enhancing the biological complexity of microfluidic NVU models and propose recommendations for elevating the biological relevance of future iterations.Importantly, the NVU is an intricate structure and it is improbable that any model will fully encompass all its aspects. Fit-for-purpose models offer a valuable compromise between physiological relevance and ease-of-use and hold the future of NVU modeling: as simple as possible, as complex as needed.
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Affiliation(s)
- Nienke R Wevers
- MIMETAS BV, De Limes 7, Oegstgeest, 2342 DH, The Netherlands.
| | - Helga E De Vries
- Amsterdam UMC location Vrije Universiteit Amsterdam, Amsterdam Neuroscience - Neuroinfection and Neuroinflammation, De Boelelaan 1117, Amsterdam, the Netherlands
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13
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Wang J, Lv F, Yin W, Gao Z, Liu H, Wang Z, Sun J. The organum vasculosum of the lamina terminalis and subfornical organ: regulation of thirst. Front Neurosci 2023; 17:1223836. [PMID: 37732311 PMCID: PMC10507174 DOI: 10.3389/fnins.2023.1223836] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2023] [Accepted: 08/22/2023] [Indexed: 09/22/2023] Open
Abstract
Thirst and water intake are regulated by the organum vasculosum of the lamina terminalis (OVLT) and subfornical organ (SFO), located around the anteroventral third ventricle, which plays a critical role in sensing dynamic changes in sodium and water balance in body fluids. Meanwhile, neural circuits involved in thirst regulation and intracellular mechanisms underlying the osmosensitive function of OVLT and SFO are reviewed. Having specific Nax channels in the glial cells and other channels (such as TRPV1 and TRPV4), the OVLT and SFO detect the increased Na+ concentration or hyperosmolality to orchestrate osmotic stimuli to the insular and cingulate cortex to evoke thirst. Meanwhile, the osmotic stimuli are relayed to the supraoptic nucleus (SON) and paraventricular nucleus of the hypothalamus (PVN) via direct neural projections or the median preoptic nucleus (MnPO) to promote the secretion of vasopressin which plays a vital role in the regulation of body fluid homeostasis. Importantly, the vital role of OVLT in sleep-arousal regulation is discussed, where vasopressin is proposed as the mediator in the regulation when OVLT senses osmotic stimuli.
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Affiliation(s)
- Jiaxu Wang
- Department of Anatomy and Neurobiology, School of Medicine, Shandong University, Jinan, Shandong, China
| | - Fenglin Lv
- Department of Anatomy and Neurobiology, School of Medicine, Shandong University, Jinan, Shandong, China
| | - Wei Yin
- Department of Anatomy and Neurobiology, School of Medicine, Shandong University, Jinan, Shandong, China
| | - Zhanpeng Gao
- Department of Anatomy and Neurobiology, School of Medicine, Shandong University, Jinan, Shandong, China
| | - Hongyu Liu
- Institute of Sport and Exercise Medicine, North University of China, Taiyuan, China
| | - Zhen Wang
- Department of Cardiology, Affiliated Hospital of Shandong University of Traditional Chinese Medicine, Jinan, China
| | - Jinhao Sun
- Department of Anatomy and Neurobiology, School of Medicine, Shandong University, Jinan, Shandong, China
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14
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Goertz JE, Garcia-Bonilla L, Iadecola C, Anrather J. Immune compartments at the brain's borders in health and neurovascular diseases. Semin Immunopathol 2023; 45:437-449. [PMID: 37138042 PMCID: PMC10279585 DOI: 10.1007/s00281-023-00992-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Accepted: 03/14/2023] [Indexed: 05/05/2023]
Abstract
Recent evidence implicates cranial border immune compartments in the meninges, choroid plexus, circumventricular organs, and skull bone marrow in several neuroinflammatory and neoplastic diseases. Their pathogenic importance has also been described for cardiovascular diseases such as hypertension and stroke. In this review, we will examine the cellular composition of these cranial border immune niches, the potential pathways through which they might interact, and the evidence linking them to cardiovascular disease.
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Affiliation(s)
- Jennifer E Goertz
- Feil Family Brain and Mind Research Institute, Weill Cornell Medicine, 407 East 61St Street; RR-405, New York, NY, 10065, USA
| | - Lidia Garcia-Bonilla
- Feil Family Brain and Mind Research Institute, Weill Cornell Medicine, 407 East 61St Street; RR-405, New York, NY, 10065, USA
| | - Costantino Iadecola
- Feil Family Brain and Mind Research Institute, Weill Cornell Medicine, 407 East 61St Street; RR-405, New York, NY, 10065, USA
| | - Josef Anrather
- Feil Family Brain and Mind Research Institute, Weill Cornell Medicine, 407 East 61St Street; RR-405, New York, NY, 10065, USA.
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15
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Miyata S. Glial functions in the blood-brain communication at the circumventricular organs. Front Neurosci 2022; 16:991779. [PMID: 36278020 PMCID: PMC9583022 DOI: 10.3389/fnins.2022.991779] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2022] [Accepted: 09/20/2022] [Indexed: 11/13/2022] Open
Abstract
The circumventricular organs (CVOs) are located around the brain ventricles, lack a blood-brain barrier (BBB) and sense blood-derived molecules. This review discusses recent advances in the importance of CVO functions, especially glial cells transferring periphery inflammation signals to the brain. The CVOs show size-limited vascular permeability, allowing the passage of molecules with molecular weight <10,000. This indicates that the lack of an endothelial cell barrier does not mean the free movement of blood-derived molecules into the CVO parenchyma. Astrocytes and tanycytes constitute a dense barrier at the distal CVO subdivision, preventing the free diffusion of blood-derived molecules into neighboring brain regions. Tanycytes in the CVOs mediate communication between cerebrospinal fluid and brain parenchyma via transcytosis. Microglia and macrophages of the CVOs are essential for transmitting peripheral information to other brain regions via toll-like receptor 2 (TLR2). Inhibition of TLR2 signaling or depletion of microglia and macrophages in the brain eliminates TLR2-dependent inflammatory responses. In contrast to TLR2, astrocytes and tanycytes in the CVOs of the brain are crucial for initiating lipopolysaccharide (LPS)-induced inflammatory responses via TLR4. Depletion of microglia and macrophages augments LPS-induced fever and chronic sickness responses. Microglia and macrophages in the CVOs are continuously activated, even under normal physiological conditions, as they exhibit activated morphology and express the M1/M2 marker proteins. Moreover, the microglial proliferation occurs in various regions, such as the hypothalamus, medulla oblongata, and telencephalon, with a marked increase in the CVOs, due to low-dose LPS administration, and after high-dose LPS administration, proliferation is seen in most brain regions, except for the cerebral cortex and hippocampus. A transient increase in the microglial population is beneficial during LPS-induced inflammation for attenuating sickness response. Transient receptor potential receptor vanilloid 1 expressed in astrocytes and tanycytes of the CVOs is responsible for thermoregulation upon exposure to a warm environment less than 37°C. Alternatively, Nax expressed in astrocytes and tanycytes of the CVOs is crucial for maintaining body fluid homeostasis. Thus, recent findings indicate that glial cells in the brain CVOs are essential for initiating neuroinflammatory responses and maintaining body fluid and thermal homeostasis.
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16
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Guselnikova VV, Razenkova VA, Sufieva DA, Korzhevskii DE. Microglia and putative macrophages of the subfornical organ: structural and functional features. BULLETIN OF RUSSIAN STATE MEDICAL UNIVERSITY 2022. [DOI: 10.24075/brsmu.2022.020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The subfornical organ is an important regulator of water-salt metabolism and energy balance of the body, involved in the control of the cardiovascular system and immune regulation. The organ comprises several cell populations, among which microglia and macrophages remain uncharacterized. This study aimed at structural, cytochemical, and functional characterization of microglia and macrophages of the subfornical organ in rats. Brain specimens were collected from mature male Wistar rats (n = 8). Microglia and macrophages were revealed by immunostaining with poly- and monoclonal antibodies against calcium-binding protein Iba1 and lysosomal protein CD68; the slides were examined by light and confocal laser microscopy. The study provides a comprehensive morphological characterization of microglial cells and macrophages of the subfornical organ. We demonstrate that the majority of Iba1-expressing cells in this area of the brain are microglial cells, not macrophages. Pre-activated state of the subfornical organ microglia may reflect structural and functional features of this organ and specific functions of local microglia. Subependymal microglial cells, the processes of which penetrate into the third ventricle of the brain, constitute a distinct subpopulation among the Iba1-expressing cells of the subfornical organ. Apart from microglial elements, the subfornical organ contains few tissue macrophages with characteristic strong expression of CD68 accompanied by undetectable or weak expression of Iba1.
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Affiliation(s)
- VV Guselnikova
- Institute of Experimental Medicine, St Petersburg, Russia
| | - VA Razenkova
- Institute of Experimental Medicine, St Petersburg, Russia
| | - DA Sufieva
- Institute of Experimental Medicine, St Petersburg, Russia
| | - DE Korzhevskii
- Institute of Experimental Medicine, St Petersburg, Russia
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17
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Transcytosis of tanycytes in the circumventricular organs of adult mouse brain. Neurosci Lett 2022; 779:136633. [DOI: 10.1016/j.neulet.2022.136633] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2022] [Revised: 03/26/2022] [Accepted: 04/11/2022] [Indexed: 12/18/2022]
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18
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Torii K, Takagi S, Yoshimura R, Miyata S. Microglial proliferation attenuates sickness responses in adult mice during endotoxin-induced inflammation. J Neuroimmunol 2022; 365:577832. [PMID: 35192968 DOI: 10.1016/j.jneuroim.2022.577832] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2021] [Revised: 02/04/2022] [Accepted: 02/14/2022] [Indexed: 12/19/2022]
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19
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Sustained microglial activation in the area postrema of collagen-induced arthritis mice. Arthritis Res Ther 2021; 23:273. [PMID: 34715926 PMCID: PMC8556992 DOI: 10.1186/s13075-021-02657-x] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2021] [Accepted: 10/12/2021] [Indexed: 02/07/2023] Open
Abstract
Background Central nervous system (CNS)-mediated symptoms, such as fatigue, depression, and hyperalgesia, are common complications among patients with rheumatoid arthritis (RA). However, it remains unclear how the peripheral pathology of RA spreads to the brain. Accumulated evidence showing an association between serum cytokine levels and aberrant CNS function suggests that humoral factors participate in this mechanism. In contrast to the well-known early responses of microglia (CNS-resident immune cells) in the area postrema [AP; a brain region lacking a blood–brain barrier (BBB)] to experimental inflammation, microglial alterations in the AP during chronic inflammation like RA remain unclear. Therefore, to determine whether microglia in the AP can react to persistent autoimmune-arthritis conditions, we analyzed these cells in a mouse model of collagen-induced arthritis (CIA). Methods Microglial number and morphology were analyzed in the AP of CIA and control mice (administered Freund’s adjuvant or saline). Immunostaining for ionized calcium-binding adaptor molecule-1 was performed at various disease phases: “pre-onset” [post-immunization day (PID) 21], “establishment” (PID 35), and “chronic” (PID 56 and 84). Quantitative analyses of microglial number and morphology were performed, with principal component analysis used to classify microglia. Interleukin-1β (IL-1β) mRNA expression was analyzed by multiple fluorescent in situ hybridization and real-time polymerase chain reaction. Behavioral changes were assessed by sucrose preference test. Results Microglia in the AP significantly increased in density and exhibited changes in morphology during the establishment and chronic phases, but not the pre-onset phase. Non-subjective clustering classification of cell morphology (CIA, 1,256 cells; saline, 852 cells) showed that the proportion of highly activated microglia increased in the CIA group during establishment and chronic phases. Moreover, the density of IL-1β-positive microglia, a hallmark of functional activation, was increased in the AP. Sucrose preferences in CIA mice negatively correlated with IL-1β expression in brain regions containing the AP. Conclusions Our findings demonstrate that microglia in the AP can sustain their activated state during persistent autoimmune arthritis, which suggests that chronic inflammation, such as RA, may affect microglia in brain regions lacking a BBB and have various neural consequences. Supplementary Information The online version contains supplementary material available at 10.1186/s13075-021-02657-x.
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20
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Hicks AI, Kobrinsky S, Zhou S, Yang J, Prager-Khoutorsky M. Anatomical Organization of the Rat Subfornical Organ. Front Cell Neurosci 2021; 15:691711. [PMID: 34552469 PMCID: PMC8450496 DOI: 10.3389/fncel.2021.691711] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Accepted: 08/10/2021] [Indexed: 11/14/2022] Open
Abstract
The subfornical organ (SFO) is a sensory circumventricular organ located along the anterodorsal wall of the third ventricle. SFO lacks a complete blood-brain barrier (BBB), and thus peripherally-circulating factors can penetrate the SFO parenchyma. These signals are detected by local neurons providing the brain with information from the periphery to mediate central responses to humoral signals and physiological stressors. Circumventricular organs are characterized by the presence of unique populations of non-neuronal cells, such as tanycytes and fenestrated endothelium. However, how these populations are organized within the SFO is not well understood. In this study, we used histological techniques to analyze the anatomical organization of the rat SFO and examined the distribution of neurons, fenestrated and non-fenestrated vasculature, tanycytes, ependymocytes, glia cells, and pericytes within its confines. Our data show that the shell of SFO contains non-fenestrated vasculature, while fenestrated capillaries are restricted to the medial-posterior core region of the SFO and associated with a higher BBB permeability. In contrast to non-fenestrated vessels, fenestrated capillaries are encased in a scaffold created by pericytes and embedded in a network of tanycytic processes. Analysis of c-Fos expression following systemic injections of angiotensin II or hypertonic NaCl reveals distinct neuronal populations responding to these stimuli. Hypertonic NaCl activates ∼13% of SFO neurons located in the shell. Angiotensin II-sensitive neurons represent ∼35% of SFO neurons and their location varies between sexes. Our study provides a comprehensive description of the organization of diverse cellular elements within the SFO, facilitating future investigations in this important brain area.
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Affiliation(s)
| | - Simona Kobrinsky
- Department of Physiology, McGill University, Montreal, QC, Canada
| | - Suijian Zhou
- Department of Physiology, McGill University, Montreal, QC, Canada
| | - Jieyi Yang
- Department of Physiology, McGill University, Montreal, QC, Canada
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21
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Jeong JK, Dow SA, Young CN. Sensory Circumventricular Organs, Neuroendocrine Control, and Metabolic Regulation. Metabolites 2021; 11:metabo11080494. [PMID: 34436435 PMCID: PMC8402088 DOI: 10.3390/metabo11080494] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2021] [Revised: 07/13/2021] [Accepted: 07/27/2021] [Indexed: 11/16/2022] Open
Abstract
The central nervous system is critical in metabolic regulation, and accumulating evidence points to a distributed network of brain regions involved in energy homeostasis. This is accomplished, in part, by integrating peripheral and central metabolic information and subsequently modulating neuroendocrine outputs through the paraventricular and supraoptic nucleus of the hypothalamus. However, these hypothalamic nuclei are generally protected by a blood-brain-barrier limiting their ability to directly sense circulating metabolic signals—pointing to possible involvement of upstream brain nuclei. In this regard, sensory circumventricular organs (CVOs), brain sites traditionally recognized in thirst/fluid and cardiovascular regulation, are emerging as potential sites through which circulating metabolic substances influence neuroendocrine control. The sensory CVOs, including the subfornical organ, organum vasculosum of the lamina terminalis, and area postrema, are located outside the blood-brain-barrier, possess cellular machinery to sense the metabolic interior milieu, and establish complex neural networks to hypothalamic neuroendocrine nuclei. Here, evidence for a potential role of sensory CVO-hypothalamic neuroendocrine networks in energy homeostasis is presented.
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Affiliation(s)
| | | | - Colin N. Young
- Correspondence: ; Tel.: +1-202-994-9575; Fax: +1-202-994-287
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22
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Bernier LP, Brunner C, Cottarelli A, Balbi M. Location Matters: Navigating Regional Heterogeneity of the Neurovascular Unit. Front Cell Neurosci 2021; 15:696540. [PMID: 34276312 PMCID: PMC8277940 DOI: 10.3389/fncel.2021.696540] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2021] [Accepted: 05/31/2021] [Indexed: 12/27/2022] Open
Abstract
The neurovascular unit (NVU) of the brain is composed of multiple cell types that act synergistically to modify blood flow to locally match the energy demand of neural activity, as well as to maintain the integrity of the blood-brain barrier (BBB). It is becoming increasingly recognized that the functional specialization, as well as the cellular composition of the NVU varies spatially. This heterogeneity is encountered as variations in vascular and perivascular cells along the arteriole-capillary-venule axis, as well as through differences in NVU composition throughout anatomical regions of the brain. Given the wide variations in metabolic demands between brain regions, especially those of gray vs. white matter, the spatial heterogeneity of the NVU is critical to brain function. Here we review recent evidence demonstrating regional specialization of the NVU between brain regions, by focusing on the heterogeneity of its individual cellular components and briefly discussing novel approaches to investigate NVU diversity.
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Affiliation(s)
- Louis-Philippe Bernier
- Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, BC, Canada
| | - Clément Brunner
- Neuro-Electronics Research Flanders, Leuven, Belgium.,Vlaams Instituut voor Biotechnologie, Leuven, Belgium.,Interuniversity Microeletronics Centre, Leuven, Belgium.,Department of Neurosciences, KU Leuven, Leuven, Belgium
| | | | - Matilde Balbi
- Queensland Brain Institute, University of Queensland, Brisbane, QLD, Australia
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23
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Osawa I, Kozawa E, Yamamoto Y, Tanaka S, Shiratori T, Kaizu A, Inoue K, Niitsu M. Contrast Enhancement of the Normal Infundibular Recess Using Heavily T2-weighted 3D FLAIR. Magn Reson Med Sci 2021; 21:469-476. [PMID: 33980787 PMCID: PMC9316133 DOI: 10.2463/mrms.mp.2021-0021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Purpose: The purpose of the present study was to evaluate contrast enhancement of the infundibular recess in the normal state using heavily T2-weighted 3D fluid-attenuated inversion recovery (FLAIR) (HT2-FLAIR). Methods: Twenty-six patients were retrospectively recruited. We subjectively assessed overall contrast enhancement of the infundibular recess between postcontrast, 4-hour (4-h) delayed postcontrast, and precontrast HT2-FLAIR images. We also objectively conducted chronological and spatial comparisons by measuring the signal intensity (SI) ratio (SIR). Chronological comparisons were performed by comparing SI of the infundibular recess/SI of the midbrain (SIRIR-MB). Spatial comparisons were conducted by comparing SI on postcontrast HT2-FLAIR/SI on precontrast HT2-FLAIR (SIRPost-Pre) of the infundibular recess with that of other cerebrospinal fluid (CSF) spaces, including the superior part of the third ventricle, lateral ventricles, fourth ventricle, and interpeduncular cistern. Results: In the subjective analysis, all cases showed contrast enhancement of the infundibular recess on both postcontrast and 4-h delayed postcontrast HT2-FLAIR, and showed weaker contrast enhancement of the infundibular recess on 4-h delayed postcontrast HT2-FLAIR than on postcontrast HT2-FLAIR. In the objective analysis, SIRIR-MB was the highest on postcontrast images, followed by 4-h delayed postcontrast images. SIRPost-Pre was significantly higher in the infundibular recess than in the other CSF spaces. Conclusion: The present results demonstrated that the infundibular recess was enhanced on HT2-FLAIR after an intravenous gadolinium injection. The infundibular recess may be a potential source of the leakage of intravenously administered gadolinium into the CSF.
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Affiliation(s)
- Iichiro Osawa
- Department of Radiology, Saitama Medical University Hospital
| | - Eito Kozawa
- Department of Radiology, Saitama Medical University Hospital
| | - Yuya Yamamoto
- Department of Radiology, Saitama Medical University Hospital
| | - Sayuri Tanaka
- Department of Radiology, Saitama Medical University Hospital
| | - Taira Shiratori
- Department of Radiology, Saitama Medical University Hospital
| | - Akane Kaizu
- Department of Radiology, Saitama Medical University Hospital
| | - Kaiji Inoue
- Department of Radiology, Saitama Medical University Hospital
| | - Mamoru Niitsu
- Department of Radiology, Saitama Medical University Hospital
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24
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Nambu Y, Horie K, Kurganov E, Miyata S. Chronic running and a corticosterone treatment attenuate astrocyte-like neural stem cell proliferation in the area postrema of the adult mouse brain. Neurosci Lett 2021; 748:135732. [PMID: 33592302 DOI: 10.1016/j.neulet.2021.135732] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2020] [Revised: 02/05/2021] [Accepted: 02/08/2021] [Indexed: 01/25/2023]
Abstract
The discovery of neural stem cells (NSCs) in the adult mammalian brain has provided insights into an extra level of brain plasticity. The proliferation and differentiation of NSCs is modulated by various physiological, pathological, and pharmacological stimuli. NSCs were recently detected in the medulla oblongata of adult rodents and humans; however, their functional significance currently remains unknown. In the present study, we examined the effects of chronic wheel-running and a corticosterone (CORT) treatment on the proliferation of astrocyte-like NSCs in the area postrema (AP) and dentate gyrus (DG). Chronic running significantly decreased the number of bromodeoxyuridine (BrdU)-labeled astrocyte-like NSCs in the AP of adult mice, but markedly increased that of BrdU+ NSCs/neural progenitor cells in the DG. The chronic CORT treatment markedly reduced the number of BrdU+ astrocyte-like NSCs in the AP, but not in the DG. These results demonstrate that the proliferation of astrocyte-like NSCs in the medulla oblongata is decreased by chronic running and a CORT treatment.
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Affiliation(s)
- Yuri Nambu
- Department of Applied Biology, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 606-8585, Japan
| | - Kohei Horie
- Department of Applied Biology, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 606-8585, Japan
| | - Erkin Kurganov
- Department of Applied Biology, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 606-8585, Japan
| | - Seiji Miyata
- Department of Applied Biology, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 606-8585, Japan.
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25
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Chen J, Haase N, Haange SB, Sucher R, Münzker J, Jäger E, Schischke K, Seyfried F, von Bergen M, Hankir MK, Krügel U, Fenske WK. Roux-en-Y gastric bypass contributes to weight loss-independent improvement in hypothalamic inflammation and leptin sensitivity through gut-microglia-neuron-crosstalk. Mol Metab 2021; 48:101214. [PMID: 33741533 PMCID: PMC8095174 DOI: 10.1016/j.molmet.2021.101214] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Revised: 02/20/2021] [Accepted: 03/12/2021] [Indexed: 12/13/2022] Open
Abstract
Objective Hypothalamic inflammation and endoplasmic reticulum (ER) stress are extensively linked to leptin resistance and overnutrition-related diseases. Surgical intervention remains the most efficient long-term weight-loss strategy for morbid obesity, but mechanisms underlying sustained feeding suppression remain largely elusive. This study investigated whether Roux-en-Y gastric bypass (RYGB) interacts with obesity-associated hypothalamic inflammation to restore central leptin signaling as a mechanistic account for post-operative appetite suppression. Methods RYGB or sham surgery was performed in high-fat diet-induced obese Wistar rats. Sham-operated rats were fed ad libitum or by weight matching to RYGB via calorie restriction (CR) before hypothalamic leptin signaling, microglia reactivity, and the inflammatory pathways were examined to be under the control of gut microbiota-derived circulating signaling. Results RYGB, other than CR-induced adiposity reduction, ameliorates hypothalamic gliosis, inflammatory signaling, and ER stress, which are linked to enhanced hypothalamic leptin signaling and responsiveness. Mechanistically, we demonstrate that RYGB interferes with hypothalamic ER stress and toll-like receptor 4 (TLR4) signaling to restore the anorexigenic action of leptin, which most likely results from modulation of a circulating factor derived from the altered gut microbial environment upon RYGB surgery. Conclusions Our data demonstrate that RYGB interferes with hypothalamic TLR4 signaling to restore the anorexigenic action of leptin, which most likely results from modulation of a circulating factor derived from the post-surgical altered gut microbial environment. RYGB surgery-related weight loss independently restores hypothalamic leptin signaling and action in diet-induced obesity. RGYB modulates hypothalamic TLR4-mediated pro-inflammatory signaling and ER stress to restore leptin's anorexigenic action. Humoral factors contribute to modulated microglia-POMC neuron interaction, which appears specific to the RYGB procedure. Altering the gut microbiota environment by antibiotics deteriorates leptin's feeding suppressive action after RYGB.
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Affiliation(s)
- Jiesi Chen
- Medical Department III, Endocrinology, Nephrology, and Rheumatology, University Hospital of Leipzig, Leipzig, Germany
| | - Nadine Haase
- Medical Department III, Endocrinology, Nephrology, and Rheumatology, University Hospital of Leipzig, Leipzig, Germany
| | - Sven-Bastiaan Haange
- Department of Molecular Systems Biology, Helmholtz Center for Environmental Research-UFZ, Permoserstraße 15, 04318 Leipzig, Germany
| | - Robert Sucher
- Division of Bariatric Surgery, Clinic of Visceral, Transplant, Thoracic, and Vascular Surgery, University Hospital, Liebigstraße 20, D-4015, Leipzig, Germany
| | - Julia Münzker
- Medical Department III, Endocrinology, Nephrology, and Rheumatology, University Hospital of Leipzig, Leipzig, Germany
| | - Elisabeth Jäger
- Medical Department III, Endocrinology, Nephrology, and Rheumatology, University Hospital of Leipzig, Leipzig, Germany
| | - Kristin Schischke
- Medical Department III, Endocrinology, Nephrology, and Rheumatology, University Hospital of Leipzig, Leipzig, Germany
| | - Florian Seyfried
- Department of General, Visceral, Transplant, Vascular, and Pediatric Surgery, University Hospital, Würzburg, Germany
| | - Martin von Bergen
- Department of Molecular Systems Biology, Helmholtz Center for Environmental Research-UFZ, Permoserstraße 15, 04318 Leipzig, Germany; Institute of Biochemistry, Faculty of Life Sciences, University of Leipzig, Talstraße 33, 04103 Leipzig, Germany
| | - Mohammed K Hankir
- Department of Experimental Surgery, University Hospital Würzburg, 97080 Würzburg, Germany
| | - Ute Krügel
- Rudolf Boehm Institute of Pharmacology and Toxicology, University of Leipzig, Härtelstraße 16-18, 04107 Leipzig, Germany
| | - Wiebke K Fenske
- Medical Department III, Endocrinology, Nephrology, and Rheumatology, University Hospital of Leipzig, Leipzig, Germany; Division of Endocrinology, Diabetes, and Metabolism, Medical Department I, University Hospital of Bonn, Bonn, Germany.
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26
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Verheggen ICM, de Jong JJA, van Boxtel MPJ, Postma AA, Verhey FRJ, Jansen JFA, Backes WH. Permeability of the windows of the brain: feasibility of dynamic contrast-enhanced MRI of the circumventricular organs. Fluids Barriers CNS 2020; 17:66. [PMID: 33115484 PMCID: PMC7594295 DOI: 10.1186/s12987-020-00228-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2020] [Accepted: 10/17/2020] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND Circumventricular organs (CVOs) are small structures without a blood-brain barrier surrounding the brain ventricles that serve homeostasic functions and facilitate communication between the blood, cerebrospinal fluid and brain. Secretory CVOs release peptides and sensory CVOs regulate signal transmission. However, pathogens may enter the brain through the CVOs and trigger neuroinflammation and neurodegeneration. We investigated the feasibility of dynamic contrast-enhanced (DCE) MRI to assess the CVO permeability characteristics in vivo, and expected significant contrast uptake in these regions, due to blood-brain barrier absence. METHODS Twenty healthy, middle-aged to older males underwent brain DCE MRI. Pharmacokinetic modeling was applied to contrast concentration time-courses of CVOs, and in reference to white and gray matter. We investigated whether a significant and positive transfer from blood to brain could be measured in the CVOs, and whether this differed between secretory and sensory CVOs or from normal-appearing brain matter. RESULTS In both the secretory and sensory CVOs, the transfer constants were significantly positive, and all secretory CVOs had significantly higher transfer than each sensory CVO. The transfer constants in both the secretory and sensory CVOs were higher than in the white and gray matter. CONCLUSIONS Current measurements confirm the often-held assumption of highly permeable CVOs, of which the secretory types have the strongest blood-to-brain transfer. The current study suggests that DCE MRI could be a promising technique to further assess the function of the CVOs and how pathogens can potentially enter the brain via these structures. TRIAL REGISTRATION Netherlands Trial Register number: NL6358, date of registration: 2017-03-24.
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Affiliation(s)
- Inge C M Verheggen
- Department of Psychiatry and Neuropsychology, Maastricht University, P.O. Box 616, 6200 MD, Maastricht, The Netherlands.
- School for Mental Health and Neuroscience (MHeNs), Maastricht University, Maastricht, The Netherlands.
- Alzheimer Center Limburg, Maastricht, The Netherlands.
| | - Joost J A de Jong
- School for Mental Health and Neuroscience (MHeNs), Maastricht University, Maastricht, The Netherlands
- Department of Radiology and Nuclear Medicine, Maastricht University Medical Center, Maastricht, The Netherlands
| | - Martin P J van Boxtel
- Department of Psychiatry and Neuropsychology, Maastricht University, P.O. Box 616, 6200 MD, Maastricht, The Netherlands
- School for Mental Health and Neuroscience (MHeNs), Maastricht University, Maastricht, The Netherlands
- Alzheimer Center Limburg, Maastricht, The Netherlands
| | - Alida A Postma
- School for Mental Health and Neuroscience (MHeNs), Maastricht University, Maastricht, The Netherlands
- Department of Radiology and Nuclear Medicine, Maastricht University Medical Center, Maastricht, The Netherlands
| | - Frans R J Verhey
- Department of Psychiatry and Neuropsychology, Maastricht University, P.O. Box 616, 6200 MD, Maastricht, The Netherlands
- School for Mental Health and Neuroscience (MHeNs), Maastricht University, Maastricht, The Netherlands
- Alzheimer Center Limburg, Maastricht, The Netherlands
| | - Jacobus F A Jansen
- School for Mental Health and Neuroscience (MHeNs), Maastricht University, Maastricht, The Netherlands
- Department of Radiology and Nuclear Medicine, Maastricht University Medical Center, Maastricht, The Netherlands
- Department of Electrical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands
| | - Walter H Backes
- School for Mental Health and Neuroscience (MHeNs), Maastricht University, Maastricht, The Netherlands
- Department of Radiology and Nuclear Medicine, Maastricht University Medical Center, Maastricht, The Netherlands
- School for Cardiovascular Research Institute Maastricht (CARIM), Maastricht University, Maastricht, The Netherlands
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Cohen-Salmon M, Slaoui L, Mazaré N, Gilbert A, Oudart M, Alvear-Perez R, Elorza-Vidal X, Chever O, Boulay AC. Astrocytes in the regulation of cerebrovascular functions. Glia 2020; 69:817-841. [PMID: 33058289 DOI: 10.1002/glia.23924] [Citation(s) in RCA: 53] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Revised: 09/18/2020] [Accepted: 09/21/2020] [Indexed: 12/18/2022]
Abstract
Astrocytes are the most numerous type of neuroglia in the brain and have a predominant influence on the cerebrovascular system; they control perivascular homeostasis, the integrity of the blood-brain barrier, the dialogue with the peripheral immune system, the transfer of metabolites from the blood, and blood vessel contractility in response to neuronal activity. These regulatory processes occur in a specialized interface composed of perivascular astrocyte extensions that almost completely cover the cerebral blood vessels. Scientists have only recently started to study how this interface is formed and how it influences cerebrovascular functions. Here, we review the literature on the astrocytes' role in the regulation of the cerebrovascular system. We cover the anatomy and development of the gliovascular interface, the known gliovascular functions, and molecular factors, the latter's implication in certain pathophysiological situations, and recent cutting-edge experimental tools developed to examine the astrocytes' role at the vascular interface. Finally, we highlight some open questions in this field of research.
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Affiliation(s)
- Martine Cohen-Salmon
- Physiology and Physiopathology of the Gliovascular Unit Research Group, Center for Interdisciplinary Research in Biology (CIRB), College de France, CNRS Unité Mixte de Recherche 724, INSERM Unité 1050, Labex Memolife, PSL Research University, Paris, France
| | - Leila Slaoui
- Physiology and Physiopathology of the Gliovascular Unit Research Group, Center for Interdisciplinary Research in Biology (CIRB), College de France, CNRS Unité Mixte de Recherche 724, INSERM Unité 1050, Labex Memolife, PSL Research University, Paris, France
| | - Noémie Mazaré
- Physiology and Physiopathology of the Gliovascular Unit Research Group, Center for Interdisciplinary Research in Biology (CIRB), College de France, CNRS Unité Mixte de Recherche 724, INSERM Unité 1050, Labex Memolife, PSL Research University, Paris, France
| | - Alice Gilbert
- Physiology and Physiopathology of the Gliovascular Unit Research Group, Center for Interdisciplinary Research in Biology (CIRB), College de France, CNRS Unité Mixte de Recherche 724, INSERM Unité 1050, Labex Memolife, PSL Research University, Paris, France
| | - Marc Oudart
- Physiology and Physiopathology of the Gliovascular Unit Research Group, Center for Interdisciplinary Research in Biology (CIRB), College de France, CNRS Unité Mixte de Recherche 724, INSERM Unité 1050, Labex Memolife, PSL Research University, Paris, France
| | - Rodrigo Alvear-Perez
- Physiology and Physiopathology of the Gliovascular Unit Research Group, Center for Interdisciplinary Research in Biology (CIRB), College de France, CNRS Unité Mixte de Recherche 724, INSERM Unité 1050, Labex Memolife, PSL Research University, Paris, France
| | - Xabier Elorza-Vidal
- Physiology and Physiopathology of the Gliovascular Unit Research Group, Center for Interdisciplinary Research in Biology (CIRB), College de France, CNRS Unité Mixte de Recherche 724, INSERM Unité 1050, Labex Memolife, PSL Research University, Paris, France
| | - Oana Chever
- Normandie University, UNIROUEN, INSERM, DC2N, IRIB, Rouen, France
| | - Anne-Cécile Boulay
- Physiology and Physiopathology of the Gliovascular Unit Research Group, Center for Interdisciplinary Research in Biology (CIRB), College de France, CNRS Unité Mixte de Recherche 724, INSERM Unité 1050, Labex Memolife, PSL Research University, Paris, France
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28
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Litvin DG, Denstaedt SJ, Borkowski LF, Nichols NL, Dick TE, Smith CB, Jacono FJ. Peripheral-to-central immune communication at the area postrema glial-barrier following bleomycin-induced sterile lung injury in adult rats. Brain Behav Immun 2020; 87:610-633. [PMID: 32097765 PMCID: PMC8895345 DOI: 10.1016/j.bbi.2020.02.006] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/18/2019] [Revised: 02/02/2020] [Accepted: 02/13/2020] [Indexed: 02/07/2023] Open
Abstract
The pathways for peripheral-to-central immune communication (P → C I-comm) following sterile lung injury (SLI) are unknown. SLI evokes systemic and central inflammation, which alters central respiratory control and viscerosensory transmission in the nucleus tractus solitarii (nTS). These functional changes coincide with increased interleukin-1 beta (IL-1β) in the area postrema, a sensory circumventricular organ that connects P → C I-comm to brainstem circuits that control homeostasis. We hypothesize that IL-1β and its downstream transcriptional target, cyclooxygenase-2 (COX-2), mediate P → C I-comm in the nTS. In a rodent model of SLI induced by intratracheal bleomycin (Bleo), the sigh frequency and duration of post-sigh apnea increased in Bleo- compared to saline- treated rats one week after injury. This SLI-dependent change in respiratory control occurred concurrently with augmented IL-1β and COX-2 immunoreactivity (IR) in the funiculus separans (FS), a barrier between the AP and the brainstem. At this barrier, increases in IL-1β and COX-2 IR were confined to processes that stained for glial fibrillary acidic protein (GFAP) and that projected basolaterally to the nTS. Further, FS radial-glia did not express TNF-α or IL-6 following SLI. To test our hypothesis, we blocked central COX-1/2 activity by intracerebroventricular (ICV) infusion of Indomethacin (Ind). Continuous ICV Ind treatment prevented Bleo-dependent increases in GFAP + and IL-1β + IR, and restored characteristics of sighs that reset the rhythm. These data indicate that changes in sighs following SLI depend partially on activation of a central COX-dependent P → C I-comm via radial-glia of the FS.
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Affiliation(s)
- David G Litvin
- Department of Physiology & Biophysics, Case Western Reserve University School of Medicine, Cleveland, OH 44106, United States; Division of Pulmonary, Critical Care and Sleep Medicine, Department of Medicine, Case Western Reserve University School of Medicine, Cleveland, OH 44106, United States; Department of Fundamental Neuroscience, University of Lausanne, 1005 Lausanne, Switzerland
| | - Scott J Denstaedt
- Division of Pulmonary, Critical Care and Sleep Medicine, Department of Medicine, Case Western Reserve University School of Medicine, Cleveland, OH 44106, United States; Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, MI 48109, United States
| | - Lauren F Borkowski
- Department of Biomedical Sciences, University of Missouri College of Veterinary Medicine, Columbia, MO 65212, United States
| | - Nicole L Nichols
- Department of Biomedical Sciences, University of Missouri College of Veterinary Medicine, Columbia, MO 65212, United States
| | - Thomas E Dick
- Division of Pulmonary, Critical Care and Sleep Medicine, Department of Medicine, Case Western Reserve University School of Medicine, Cleveland, OH 44106, United States; Department of Neurosciences, Case Western Reserve University School of Medicine, Cleveland, OH 44106, United States
| | - Corey B Smith
- Department of Physiology & Biophysics, Case Western Reserve University School of Medicine, Cleveland, OH 44106, United States
| | - Frank J Jacono
- Division of Pulmonary, Critical Care and Sleep Medicine, Department of Medicine, Case Western Reserve University School of Medicine, Cleveland, OH 44106, United States; Division of Pulmonary, Critical Care and Sleep Medicine, Louis Stokes VA Medical Center, Cleveland, OH 44106, United States.
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Depletion of microglia and macrophages with clodronate liposomes attenuates zymosan-induced Fos expression and hypothermia in the adult mouse. J Neuroimmunol 2020; 344:577244. [DOI: 10.1016/j.jneuroim.2020.577244] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2020] [Revised: 04/04/2020] [Accepted: 04/14/2020] [Indexed: 12/14/2022]
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Mastorakos P, McGavern D. The anatomy and immunology of vasculature in the central nervous system. Sci Immunol 2020; 4:4/37/eaav0492. [PMID: 31300479 DOI: 10.1126/sciimmunol.aav0492] [Citation(s) in RCA: 216] [Impact Index Per Article: 43.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2019] [Accepted: 06/13/2019] [Indexed: 12/21/2022]
Abstract
Barriers between circulation and the central nervous system (CNS) play a key role in the development and modulation of CNS immune responses. Structural variations in the vasculature traversing different anatomical regions within the CNS strongly influence where and how CNS immune responses first develop. Here, we provide an overview of cerebrovascular anatomy, focusing on the blood-CNS interface and how anatomical variations influence steady-state immunology in the compartment. We then discuss how CNS vasculature is affected by and influences the development of different pathophysiological states, such as CNS autoimmune disease, cerebrovascular injury, cerebral ischemia, and infection.
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Affiliation(s)
- Panagiotis Mastorakos
- Viral Immunology and Intravital Imaging Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA
| | - Dorian McGavern
- Viral Immunology and Intravital Imaging Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA.
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31
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Asami A, Kurganov E, Miyata S. Proliferation of endothelial cells in the choroid plexus of normal and hydrocephalic mice. J Chem Neuroanat 2020; 106:101796. [PMID: 32360474 DOI: 10.1016/j.jchemneu.2020.101796] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2020] [Revised: 04/16/2020] [Accepted: 04/16/2020] [Indexed: 01/08/2023]
Abstract
The choroid plexus (CP), located at the walls of the brain ventricles, produces and secretes cerebrospinal fluid (CSF). Hydrocephalus is a neurological disorder in which the CP abnormally secretes excess amounts of CSF into the ventricles. There is currently no information on the vascular dynamics of the CP in adult brains under normal and hydrocephalic conditions. In the present study, we reported the continuous proliferation of endothelial cells in the CP of normal mice, which depended on vascular endothelial cell growth factor (VEGF). The proliferation of endothelial cells increased in mice with intraventricular hemorrhage, which was attenuated by a pretreatment with the toll-like receptor 4 (TLR4) inhibitor VIPER. Moreover, the intracerebroventricular infusion of the TLR4 agonist, lipopolysaccharide, increased endothelial cell proliferation in the CP and induced ventriculomegaly. The present results provide insights into the importance of the TLR4-initiated and VEGF-dependent proliferation of endothelial cells in the pathogenesis of hydrocephalus.
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Affiliation(s)
- Ayumi Asami
- Department of Applied Biology, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 606-8585, Japan
| | - Erkin Kurganov
- Department of Applied Biology, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 606-8585, Japan
| | - Seiji Miyata
- Department of Applied Biology, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 606-8585, Japan.
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32
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Kawai S, Kurganov E, Miyata S. Transient increase of microglial C1q expression in the circumventricular organs of adult mouse during LPS-induced inflammation. Cell Biochem Funct 2020; 38:392-400. [PMID: 31904875 DOI: 10.1002/cbf.3477] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2018] [Revised: 10/14/2019] [Accepted: 12/15/2019] [Indexed: 12/20/2022]
Abstract
The circumventricular organs (CVOs) are the brain regions that lack the blood-brain barrier and allow free entry of blood-derived molecules, offering specialized niche to initiate rapid and early neuroinflammatory responses in the brain. Complement component 1q (C1q) is shown to be the first recognition component of the complement pathway and has a crucial function in the brain under pathological conditions. In the present study, we found that C1q expression in CX3CR1-positive microglia was increased in the CVOs and their neighbouring brain regions of adult mice at 1 day after a single administration of 1 mg/kg lipopolysaccharide (LPS), whereas it returned to control levels at 3 days after LPS stimulation. C1q expression was also seen to localize at synapsin-positive presynaptic axonal terminals in various brain regions. Thus, the present study demonstrates a transient upregulation of microglial C1q expression in the CVOs and their adjacent brain regions, indicating that a transient upregulation of C1q is possibly concerned with physiological responses at early phase of brain inflammation. SIGNIFICANCE OF THE STUDY: The circumventricular organs (CVOs) are specialized brain regions that lack the blood-brain barrier (BBB) and initiate neuroinflammatory responses in the brains. The present study showed that the expression of complement protein C1q was highly increased in microglia of the CVOs and their adjacent brain regions. Moreover, C1q expression was observed to localize specifically at presynaptic axonal terminals in the CVOs and their neighbouring brain regions. Thus, the present study indicates that C1q is possibly correlated with physiological responses at early phase of brain inflammation.
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Affiliation(s)
- Shintaro Kawai
- Department of Applied Biology, Kyoto Institute of Technology, Kyoto, Japan
| | - Erkin Kurganov
- Department of Applied Biology, Kyoto Institute of Technology, Kyoto, Japan
| | - Seiji Miyata
- Department of Applied Biology, Kyoto Institute of Technology, Kyoto, Japan
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33
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Abstract
The blood-brain barrier (BBB) protects the vertebrate central nervous system from harmful blood-borne, endogenous and exogenous substances to ensure proper neuronal function. The BBB describes a function that is established by endothelial cells of CNS vessels in conjunction with pericytes, astrocytes, neurons and microglia, together forming the neurovascular unit (NVU). Endothelial barrier function is crucially induced and maintained by the Wnt/β-catenin pathway and requires intact NVU for proper functionality. The BBB and the NVU are characterized by a specialized assortment of molecular specializations, providing the basis for tightening, transport and immune response functionality.The present chapter introduces state-of-the-art knowledge of BBB structure and function and highlights current research topics, aiming to understanding in more depth the cellular and molecular interactions at the NVU, determining functionality of the BBB in health and disease, and providing novel potential targets for therapeutic BBB modulation. Moreover, we highlight recent advances in understanding BBB and NVU heterogeneity within the CNS as well as their contribution to CNS physiology, such as neurovascular coupling, and pathophysiology, is discussed. Finally, we give an outlook onto new avenues of BBB research.
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Affiliation(s)
- Fabienne Benz
- Institute of Neurology (Edinger Institute), University Hospital, Goethe University Frankfurt, Frankfurt am Main, Germany
| | - Stefan Liebner
- Institute of Neurology (Edinger Institute), University Hospital, Goethe University Frankfurt, Frankfurt am Main, Germany.
- Excellence Cluster Cardio Pulmonary System (CPI), Partner Site Frankfurt, Frankfurt, Germany.
- German Center for Cardiovascular Research (DZHK), Partner Site Frankfurt/Mainz, Frankfurt, Germany.
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34
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Kálmán M, Oszwald E, Pócsai K. Three-plane description of astroglial populations of OVLT subdivisions in rat: Tanycyte connections to distant parts of third ventricle. J Comp Neurol 2019; 527:2793-2812. [PMID: 31045238 DOI: 10.1002/cne.24707] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2018] [Revised: 04/22/2019] [Accepted: 04/23/2019] [Indexed: 11/07/2022]
Abstract
This study demonstrates glial and gliovascular markers of organon vasculosum laminae terminalis (OVLT) in three planes. The distribution of glial markers displayed similarities to the subfornical organ. There was an inner part with vimentin- and nestin-immunopositive glia whereas GFAP and the water-channel aquaporin 4 were found at the periphery. This separation indicates different functions of the two regions. The presence of nestin may indicate stem cell-capabilities whereas aquaporin 4 has been reported to promote the osmoreceptor function. Glutamine synthetase immunoreactivity was sparse like in the area postrema and subfornical organ. The laminin and β-dystroglycan immunolabelings altered along the vessels such as in the subfornical organ indicating altering gliovascular relations. The different subdivisions of OVLT received glial processes of different origins. The posterior periventricular zone contained short vimentin-immunopositive processes from the ependyma of the adjacent surface of the third ventricle. The lateral periventricular zone received forceps-like process systems from the anterolateral part of the third ventricle. Most interestingly, the "dorsal cap" received a mixed group of long GFAP- and vimentin-immunopositive processes from a distant part of the third ventricle. The processes may have two functions: a guidance for newly produced cells like radial glia in immature brain and/or a connection between distant parts of the third ventricle and OVLT.
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Affiliation(s)
- Mihály Kálmán
- Department of Anatomy, Histology and Embryology, Semmelweis University, Budapest, Hungary
| | - Erzsébet Oszwald
- Department of Anatomy, Histology and Embryology, Semmelweis University, Budapest, Hungary
| | - Károly Pócsai
- Department of Anatomy, Histology and Embryology, Semmelweis University, Budapest, Hungary
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35
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Lainez NM, Coss D. Obesity, Neuroinflammation, and Reproductive Function. Endocrinology 2019; 160:2719-2736. [PMID: 31513269 PMCID: PMC6806266 DOI: 10.1210/en.2019-00487] [Citation(s) in RCA: 89] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/02/2019] [Accepted: 09/04/2019] [Indexed: 12/13/2022]
Abstract
The increasing occurrence of obesity has become a significant public health concern. Individuals with obesity have higher prevalence of heart disease, stroke, osteoarthritis, diabetes, and reproductive disorders. Reproductive problems include menstrual irregularities, pregnancy complications, and infertility due to anovulation, in women, and lower testosterone and diminished sperm count, in men. In particular, women with obesity have reduced levels of both gonadotropin hormones, and, in obese men, lower testosterone is accompanied by diminished LH. Taken together, these findings indicate central dysregulation of the hypothalamic-pituitary-gonadal axis, specifically at the level of the GnRH neuron function, which is the final brain output for the regulation of reproduction. Obesity is a state of hyperinsulinemia, hyperlipidemia, hyperleptinemia, and chronic inflammation. Herein, we review recent advances in our understanding of how these metabolic and immune changes affect hypothalamic function and regulation of GnRH neurons. In the latter part, we focus on neuroinflammation as a major consequence of obesity and discuss findings that reveal that GnRH neurons are uniquely positioned to respond to inflammatory changes.
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Affiliation(s)
- Nancy M Lainez
- Division of Biomedical Sciences, School of Medicine, University of California, Riverside, Riverside, California
| | - Djurdjica Coss
- Division of Biomedical Sciences, School of Medicine, University of California, Riverside, Riverside, California
- Correspondence: Djurdjica Coss, PhD, Division of Biomedical Sciences, School of Medicine, University of California, Riverside, 303 SOM Research Building, 900 University Avenue, Riverside, California 92521. E-mail:
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Murayama S, Kurganov E, Miyata S. Activation of microglia and macrophages in the circumventricular organs of the mouse brain during TLR2-induced fever and sickness responses. J Neuroimmunol 2019; 334:576973. [PMID: 31170673 DOI: 10.1016/j.jneuroim.2019.576973] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2019] [Revised: 05/26/2019] [Accepted: 05/27/2019] [Indexed: 01/28/2023]
Abstract
Toll-like receptor 2 (TLR2) recognizes cell wall components from Gram-positive bacteria. Until now, however, little has been known about the significance of brain TLR2 in controlling inflammation and thermoregulatory responses during systemic Gram-positive bacterial infection. In the present study, the TLR2 immunoreactivity was seen to be prominent in the microglia/macrophages of the circumventricular organs (CVOs) of the mouse brain. The intraperitoneal injection of Pam3CSK4, a TLR2 agonist, induced nuclear factor-κ B activation in the microglia/macrophages of the CVOs. The injection of Pam3CSK4 also produced the expression of Fos at astrocytes and neurons in the CVOs and the regions neighboring the CVOs. The Pam3CSK4 injection induced fever and sickness responses. Pretreatment with lipopolysaccharide, a TLR4 agonist, augmented the Pam3CSK4-induced fever together with the increased TLR2 immunoreactivity. These results indicate that the TLR2 in microglia/macrophages of the CVOs are possibly associated with initiating and transmitting inflammatory responses in the brain.
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Affiliation(s)
- Saki Murayama
- Department of Applied Biology, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 606-8585, Japan
| | - Erkin Kurganov
- Department of Applied Biology, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 606-8585, Japan
| | - Seiji Miyata
- Department of Applied Biology, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 606-8585, Japan.
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Morita-Takemura S, Wanaka A. Blood-to-brain communication in the hypothalamus for energy intake regulation. Neurochem Int 2019; 128:135-142. [DOI: 10.1016/j.neuint.2019.04.007] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2018] [Revised: 04/08/2019] [Accepted: 04/11/2019] [Indexed: 01/03/2023]
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Muneoka S, Murayama S, Nakano Y, Miyata S. TLR4 in circumventricular neural stem cells is a negative regulator for thermogenic pathways in the mouse brain. J Neuroimmunol 2019; 331:58-73. [DOI: 10.1016/j.jneuroim.2018.04.017] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2017] [Revised: 04/23/2018] [Accepted: 04/30/2018] [Indexed: 12/22/2022]
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Benz F, Wichitnaowarat V, Lehmann M, Germano RF, Mihova D, Macas J, Adams RH, Taketo MM, Plate KH, Guérit S, Vanhollebeke B, Liebner S. Low wnt/β-catenin signaling determines leaky vessels in the subfornical organ and affects water homeostasis in mice. eLife 2019; 8:43818. [PMID: 30932814 PMCID: PMC6481993 DOI: 10.7554/elife.43818] [Citation(s) in RCA: 58] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2018] [Accepted: 03/28/2019] [Indexed: 12/17/2022] Open
Abstract
The circumventricular organs (CVOs) in the central nervous system (CNS) lack a vascular blood-brain barrier (BBB), creating communication sites for sensory or secretory neurons, involved in body homeostasis. Wnt/β-catenin signaling is essential for BBB development and maintenance in endothelial cells (ECs) in most CNS vessels. Here we show that in mouse development, as well as in adult mouse and zebrafish, CVO ECs rendered Wnt-reporter negative, suggesting low level pathway activity. Characterization of the subfornical organ (SFO) vasculature revealed heterogenous claudin-5 (Cldn5) and Plvap/Meca32 expression indicative for tight and leaky vessels, respectively. Dominant, EC-specific β-catenin transcription in mice, converted phenotypically leaky into BBB-like vessels, by augmenting Cldn5+vessels, stabilizing junctions and by reducing Plvap/Meca32+ and fenestrated vessels, resulting in decreased tracer permeability. Endothelial tightening augmented neuronal activity in the SFO of water restricted mice. Hence, regulating the SFO vessel barrier may influence neuronal function in the context of water homeostasis. Infections and diseases in the brain and spine can be very damaging and debilitating. Indeed, the central nervous system also needs a carefully controlled biochemical environment to survive. As such, all animals with a backbone have barriers and defenses to protect and preserve this key system. One of these is the blood-brain barrier, a physical barrier between the brain and the outside world. Where most blood vessels allow relatively free exchange of chemicals between the blood and surrounding cells, the blood-brain barrier controls what can move between the bloodstream and the brain. Yet, there are gaps in the blood-brain barrier, specifically within structures in the brain called the circumventricular organs. These leaky vessels allow the brain cells in these regions to monitor the blood and respond to changes, for example, by triggering sensations such as hunger, thirst or nausea. It is not clear what stops the blood-brain barrier from forming in these regions and what effect the presence of a barrier would have on the brains activity, or the health and behavior of the animal. Benz et al. have now used mice and zebrafish to examine the development and structure of the blood-brain barrier. The investigation revealed that the signals that induce the blood-brain barrier throughout the brain are absent in the circumventricular organs of both species. Next, by artificially activating a protein involved in cell-cell interactions in mice, Benz et al. created blood-brain barrier-like structures in circumventricular organs by converting the leaky vessels into tight ones. This change meant that the brain cells in these regions did not respond properly to water deprivation, which potentially may have affected the regulation of thirst in these mice. Understanding the blood-brain barrier could have a variety of impacts on how we treat diseases in the central nervous system. This includes stroke, brain tumors and Alzheimers disease. These findings could particularly help scientists to better understand conditions that affect basic needs like thirst and hunger.
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Affiliation(s)
- Fabienne Benz
- Institute of Neurology (Edinger Institute), University Hospital, Goethe University Frankfurt, Frankfurt am Main, Germany
| | - Viraya Wichitnaowarat
- Institute of Neurology (Edinger Institute), University Hospital, Goethe University Frankfurt, Frankfurt am Main, Germany
| | - Martin Lehmann
- Institute of Neurology (Edinger Institute), University Hospital, Goethe University Frankfurt, Frankfurt am Main, Germany
| | - Raoul Fv Germano
- Laboratory of Neurovascular Signaling, Department of Molecular Biology, ULB Neuroscience Institute, Université libre de Bruxelles, Bruxelles, Belgium
| | - Diana Mihova
- Institute of Neurology (Edinger Institute), University Hospital, Goethe University Frankfurt, Frankfurt am Main, Germany
| | - Jadranka Macas
- Institute of Neurology (Edinger Institute), University Hospital, Goethe University Frankfurt, Frankfurt am Main, Germany
| | - Ralf H Adams
- Department of Tissue Morphogenesis, Max-Planck-Institute for Molecular Biomedicine, University of Münster, Faculty of Medicine, Münster, Germany
| | - M Mark Taketo
- Division of Experimental Therapeutics, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Karl-Heinz Plate
- Institute of Neurology (Edinger Institute), University Hospital, Goethe University Frankfurt, Frankfurt am Main, Germany.,Excellence Cluster Cardio-Pulmonary systems (ECCPS), Partner site Frankfurt, Frankfurt, Germany.,German Cancer Consortium (DKTK), Partner Site Frankfurt/Mainz, Frankfurt, Germany.,German Center for Cardiovascular Research (DZHK), Partner site Frankfurt/Mainz, Frankfurt, Germany.,German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Sylvaine Guérit
- Institute of Neurology (Edinger Institute), University Hospital, Goethe University Frankfurt, Frankfurt am Main, Germany
| | - Benoit Vanhollebeke
- Laboratory of Neurovascular Signaling, Department of Molecular Biology, ULB Neuroscience Institute, Université libre de Bruxelles, Bruxelles, Belgium.,Walloon Excellence in Life Sciences and Biotechnology (WELBIO), Wallonia, Belgium
| | - Stefan Liebner
- Institute of Neurology (Edinger Institute), University Hospital, Goethe University Frankfurt, Frankfurt am Main, Germany.,Excellence Cluster Cardio-Pulmonary systems (ECCPS), Partner site Frankfurt, Frankfurt, Germany.,German Cancer Consortium (DKTK), Partner Site Frankfurt/Mainz, Frankfurt, Germany
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40
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McKinley MJ, Denton DA, Ryan PJ, Yao ST, Stefanidis A, Oldfield BJ. From sensory circumventricular organs to cerebral cortex: Neural pathways controlling thirst and hunger. J Neuroendocrinol 2019; 31:e12689. [PMID: 30672620 DOI: 10.1111/jne.12689] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/05/2018] [Revised: 01/20/2019] [Accepted: 01/21/2019] [Indexed: 01/14/2023]
Abstract
Much progress has been made during the past 30 years with respect to elucidating the neural and endocrine pathways by which bodily needs for water and energy are brought to conscious awareness through the generation of thirst and hunger. One way that circulating hormones influence thirst and hunger is by acting on neurones within sensory circumventricular organs (CVOs). This is possible because the subfornical organ and organum vasculosum of the lamina terminalis (OVLT), the sensory CVOs in the forebrain, and the area postrema in the hindbrain lack a normal blood-brain barrier such that neurones within them are exposed to blood-borne agents. The neural signals generated by hormonal action in these sensory CVOs are relayed to several sites in the cerebral cortex to stimulate or inhibit thirst or hunger. The subfornical organ and OVLT respond to circulating angiotensin II, relaxin and hypertonicity to drive thirst-related neural pathways, whereas circulating amylin, leptin and possibly glucagon-like peptide-1 act at the area postrema to influence neural pathways inhibiting food intake. As a result of investigations using functional brain imaging techniques, the insula and anterior cingulate cortex, as well as several other cortical sites, have been implicated in the conscious perception of thirst and hunger in humans. Viral tracing techniques show that the anterior cingulate cortex and insula receive neural inputs from thirst-related neurones in the subfornical organ and OVLT, with hunger-related neurones in the area postrema having polysynaptic efferent connections to these cortical regions. For thirst, initially, the median preoptic nucleus and, subsequently, the thalamic paraventricular nucleus and lateral hypothalamus have been identified as likely sites of synaptic links in pathways from the subfornical organ and OVLT to the cortex. The challenge remains to identify the links in the neural pathways that relay signals originating in sensory CVOs to cortical sites subserving either thirst or hunger.
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Affiliation(s)
- Michael J McKinley
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, Victoria, Australia
- Department of Physiology, University of Melbourne, Parkville, Victoria, Australia
| | - Derek A Denton
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, Victoria, Australia
- Office of the Dean of Medicine, University of Melbourne, Parkville, Victoria, Australia
| | - Philip J Ryan
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, Victoria, Australia
| | - Song T Yao
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, Victoria, Australia
| | - Aneta Stefanidis
- Department of Physiology, Monash University, Clayton, Victoria, Australia
| | - Brian J Oldfield
- Department of Physiology, Monash University, Clayton, Victoria, Australia
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41
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Morita-Takemura S, Nakahara K, Hasegawa-Ishii S, Isonishi A, Tatsumi K, Okuda H, Tanaka T, Kitabatake M, Ito T, Wanaka A. Responses of perivascular macrophages to circulating lipopolysaccharides in the subfornical organ with special reference to endotoxin tolerance. J Neuroinflammation 2019; 16:39. [PMID: 30764851 PMCID: PMC6375194 DOI: 10.1186/s12974-019-1431-6] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2018] [Accepted: 02/04/2019] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Circulating endotoxins including lipopolysaccharides (LPS) cause brain responses such as fever and decrease of food and water intake, while pre-injection of endotoxins attenuates these responses. This phenomenon is called endotoxin tolerance, but the mechanisms underlying it remain unclear. The subfornical organ (SFO) rapidly produces proinflammatory cytokines including interleukin-1β (IL-1β) in response to peripherally injected LPS, and repeated LPS injection attenuates IL-1β production in the SFO, indicating that the SFO is involved in endotoxin tolerance. The purpose of this study is to investigate features of the IL-1β source cells in the SFO of LPS-non-tolerant and LPS-tolerant mice. METHODS We first established the endotoxin-tolerant mouse model by injecting LPS into adult male mice (C57BL/6J). Immunohistochemistry was performed to characterize IL-1β-expressing cells, which were perivascular macrophages in the SFO. We depleted perivascular macrophages using clodronate liposomes to confirm the contribution of IL-1β production. To assess the effect of LPS pre-injection on perivascular macrophages, we transferred bone marrow-derived cells obtained from male mice (C57BL/6-Tg (CAG-EGFP)) to male recipient mice (C57BL/6N). Finally, we examined the effect of a second LPS injection on IL-1β expression in the SFO perivascular macrophages. RESULTS We report that perivascular macrophages but not parenchymal microglia rapidly produced the proinflammatory cytokine IL-1β in response to LPS. We found that peripherally injected LPS localized in the SFO perivascular space. Depletion of macrophages by injection of clodronate liposomes attenuated LPS-induced IL-1β expression in the SFO. When tolerance developed to LPS-induced sickness behavior in mice, the SFO perivascular macrophages ceased producing IL-1β, although bone marrow-derived perivascular macrophages increased in number in the SFO and peripherally injected LPS reached the SFO perivascular space. CONCLUSIONS The current data indicate that perivascular macrophages enable the SFO to produce IL-1β in response to circulating LPS and that its hyporesponsiveness may be the cause of endotoxin tolerance.
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Affiliation(s)
- Shoko Morita-Takemura
- Department of Anatomy and Neuroscience, Faculty of Medicine, Nara Medical University, 840 Shijo-cho, Kashihara, Nara, 634-8521, Japan.
| | - Kazuki Nakahara
- Department of Anatomy and Neuroscience, Faculty of Medicine, Nara Medical University, 840 Shijo-cho, Kashihara, Nara, 634-8521, Japan
| | | | - Ayami Isonishi
- Department of Anatomy and Neuroscience, Faculty of Medicine, Nara Medical University, 840 Shijo-cho, Kashihara, Nara, 634-8521, Japan
| | - Kouko Tatsumi
- Department of Anatomy and Neuroscience, Faculty of Medicine, Nara Medical University, 840 Shijo-cho, Kashihara, Nara, 634-8521, Japan
| | - Hiroaki Okuda
- Department of Anatomy and Neuroscience, Faculty of Medicine, Nara Medical University, 840 Shijo-cho, Kashihara, Nara, 634-8521, Japan.,Department of Anatomy, Graduate School of Medical Science, Kanazawa University, Kanazawa, Japan
| | - Tatsuhide Tanaka
- Department of Anatomy and Neuroscience, Faculty of Medicine, Nara Medical University, 840 Shijo-cho, Kashihara, Nara, 634-8521, Japan
| | | | - Toshihiro Ito
- Department of Immunology, Nara Medical University, Kashihara, Nara, Japan
| | - Akio Wanaka
- Department of Anatomy and Neuroscience, Faculty of Medicine, Nara Medical University, 840 Shijo-cho, Kashihara, Nara, 634-8521, Japan
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42
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Bentivoglio M, Kristensson K, Rottenberg ME. Circumventricular Organs and Parasite Neurotropism: Neglected Gates to the Brain? Front Immunol 2018; 9:2877. [PMID: 30619260 PMCID: PMC6302769 DOI: 10.3389/fimmu.2018.02877] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2018] [Accepted: 11/22/2018] [Indexed: 12/20/2022] Open
Abstract
Circumventricular organs (CVOs), neural structures located around the third and fourth ventricles, harbor, similarly to the choroid plexus, vessels devoid of a blood-brain barrier (BBB). This enables them to sense immune-stimulatory molecules in the blood circulation, but may also increase chances of exposure to microbes. In spite of this, attacks to CVOs by microbes are rarely described. It is here highlighted that CVOs and choroid plexus can be infected by pathogens circulating in the bloodstream, providing a route for brain penetration, as shown by infections with the parasites Trypanosoma brucei. Immune responses elicited by pathogens or systemic infections in the choroid plexus and CVOs are briefly outlined. From the choroid plexus trypanosomes can seed into the ventricles and initiate accelerated infiltration of T cells and parasites in periventricular areas. The highly motile trypanosomes may also enter the brain parenchyma from the median eminence, a CVO located at the base of the third ventricle, by crossing the border into the BBB-protected hypothalamic arcuate nuclei. A gate may, thus, be provided for trypanosomes to move into brain areas connected to networks of regulation of circadian rhythms and sleep-wakefulness, to which other CVOs are also connected. Functional imbalances in these networks characterize human African trypanosomiasis, also called sleeping sickness. They are distinct from the sickness response to bacterial infections, but can occur in common neuropsychiatric diseases. Altogether the findings lead to the question: does the neglect in reporting microbe attacks to CVOs reflect lack of awareness in investigations or of gate-opening capability by microbes?
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Affiliation(s)
- Marina Bentivoglio
- Department of Neuroscience Biomedicine and Movement Sciences, University of Verona, Verona, Italy
| | | | - Martin E. Rottenberg
- Department Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden
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43
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Al-Kaabi M, Hussam F, Al-Marsoummi S, Al-Anbaki A, Al-Salihi A, Al-Aubaidy H. Expression of ZO1, vimentin, pan-cadherin and AGTR1 in tanycyte-like cells of the sulcus medianus organum. Biochem Biophys Res Commun 2018; 502:243-249. [PMID: 29803674 DOI: 10.1016/j.bbrc.2018.05.151] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2018] [Accepted: 05/22/2018] [Indexed: 11/19/2022]
Abstract
Tanycytes are a specialized ependymal lining of brain ventricles with exceptional features of having long basal processes and junctional complexes between cell bodies. These tanycytes are present at the regions of circumventricular organs (CVOs) which possess common morphological and functional features enabling them to be described as the brain windows where the barrier systems have special properties. Previous studies detailed seven of these CVOs but little information is available regarding another putative site at the rostral part of the median sulcus of the 4th ventricle, or the sulcus medianus organum (SMO). Here we performed a pilot immunohistochemical study to support earlier observations suggesting the SMO as a novel CVO. We labeled rat brain with ZO1, vimentin, pan-cadherin and angiotensin II type 1 receptors markers which showed a morphologically distinct population of cells at the region of the SMO similar to tanycytes present in the median eminence, a known CVO. These cells had basal processes reaching the deeply seated blood vessels while the caudal part of the median sulcus did not show similar long cellular extensions. We concluded that tanycyte-like cells are present in the SMO in a pattern resembling that of other CVOs where the strategic location of the SMO is probably for signal integration between brainstem nuclei and the rostrally located neuronal centers.
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Affiliation(s)
- Muthanna Al-Kaabi
- Al-Nahrain University, College of Medicine, Department of Human Anatomy, Baghdad, Iraq; University of Tasmania, Faculty of Health, School of Medicine, Medical Science Precinct, Hobart, Tasmania, Australia
| | - Fadhil Hussam
- Al-Nahrain University, College of Medicine, Department of Human Anatomy, Baghdad, Iraq
| | - Sarmad Al-Marsoummi
- Al-Nahrain University, College of Medicine, Department of Human Anatomy, Baghdad, Iraq; University of North Dakota, School of Medicine and Health Sciences, Department of Biomedical Sciences, North Dakota, USA
| | - Ali Al-Anbaki
- University of Manchester, Faculty of Biology, Medicine and Health, Manchester, UK
| | - Anam Al-Salihi
- Al-Nahrain University, College of Medicine, Department of Human Anatomy, Baghdad, Iraq
| | - Hayder Al-Aubaidy
- La Trobe University, School of Life Sciences, Department of Physiology, Anatomy & Microbiology, Bundoora, VIC, 3086, Australia.
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44
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Abstract
The circumventricular organs (CVOs) are specialised neuroepithelial structures found in the midline of the brain, grouped around the third and fourth ventricles. They mediate the communication between the brain and the periphery by performing sensory and secretory roles, facilitated by increased vascularisation and the absence of a blood-brain barrier. Surprisingly little is known about the origins of the CVOs (both developmental and evolutionary), but their functional and organisational similarities raise the question of the extent of their relationship. Here, I review our current knowledge of the embryonic development of the seven major CVOs (area postrema, median eminence, neurohypophysis, organum vasculosum of the lamina terminalis, pineal organ, subcommissural organ, subfornical organ) in embryos of different vertebrate species. Although there are conspicuous similarities between subsets of CVOs, no unifying feature characteristic of their development has been identified. Cross-species comparisons suggest that CVOs also display a high degree of evolutionary flexibility. Thus, the term 'CVO' is merely a functional definition, and features shared by multiple CVOs may be the result of homoplasy rather than ontogenetic or phylogenetic relationships.
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Affiliation(s)
- Clemens Kiecker
- Department of Developmental NeurobiologyKing's College LondonLondonUK
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45
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Furube E, Kawai S, Inagaki H, Takagi S, Miyata S. Brain Region-dependent Heterogeneity and Dose-dependent Difference in Transient Microglia Population Increase during Lipopolysaccharide-induced Inflammation. Sci Rep 2018; 8:2203. [PMID: 29396567 PMCID: PMC5797160 DOI: 10.1038/s41598-018-20643-3] [Citation(s) in RCA: 92] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2017] [Accepted: 01/23/2018] [Indexed: 12/26/2022] Open
Abstract
Numerous studies have reported the importance of microglial activation in various pathological conditions, whereas little attention has been given to the point for dynamics of microglial population under infection-induced inflammation. In the present study, the single systemic stimulation of 100 μg/kg lipopolysaccharide (LPS) induced robust microglial proliferation only in the circumventricular organs (CVOs) and their neighboring brain regions. More than half of microglia similarly showed proliferative activity in the CVOs and their neighboring brain regions after 1 mg/kg LPS stimulation, while this stimulation expanded microglia-proliferating brain regions including the hypothalamus, medulla oblongata, and limbic system. Microglia proliferation resulted in a transient increase of microglial density, since their density almost returned to basal levels within 3 weeks. Divided microglia survived at the same rate as non-divided ones. Proliferating microglia frequently expressed a resident microglia marker Tmem119, indicating that increase of microglia density is due to the proliferation of resident microglia. Thus, the present study demonstrates that transient increase in microglia density depends on the brain region and dose of LPS during infection-induced inflammation and could provide a new insight on microglia functions in inflammation and pathogenesis of brain diseases.
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Affiliation(s)
- Eriko Furube
- Department of Applied Biology, Kyoto, 606-8585, Japan
| | | | | | - Shohei Takagi
- Department of Applied Biology, Kyoto, 606-8585, Japan
| | - Seiji Miyata
- Department of Applied Biology, Kyoto, 606-8585, Japan.
- The Center for Advanced Insect Research Promotion, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto, 606-8585, Japan.
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46
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Abstract
Hypothalamic integration of gastrointestinal and adipose tissue-derived hormones serves as a key element of neuroendocrine control of food intake. Leptin, adiponectin, oleoylethanolamide, cholecystokinin, and ghrelin, to name a few, are in a constant "cross talk" with the feeding-related brain circuits that encompass hypothalamic populations synthesizing anorexigens (melanocortins, CART, oxytocin) and orexigens (Agouti-related protein, neuropeptide Y, orexins). While this integrated neuroendocrine circuit successfully ensures that enough energy is acquired, it does not seem to be equally efficient in preventing excessive energy intake, especially in the obesogenic environment in which highly caloric and palatable food is constantly available. The current review presents an overview of intricate mechanisms underlying hypothalamic integration of energy balance-related peripheral endocrine input. We discuss vulnerabilities and maladaptive neuroregulatory processes, including changes in hypothalamic neuronal plasticity that propel overeating despite negative consequences.
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47
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Abstract
PURPOSE OF REVIEW The central nervous system plays a pivotal role in the regulation of extracellular fluid volume and consequently arterial blood pressure. Key hypothalamic regions sense and integrate neurohumoral signals to subsequently alter intake (thirst and salt appetite) and output (renal excretion via neuroendocrine and autonomic function). Here, we review recent findings that provide new insight into such mechanisms that may represent new therapeutic targets. RECENT FINDINGS Implementation of cutting edge neuroscience approaches such as opto- and chemogenetics highlight pivotal roles of circumventricular organs to impact body fluid homeostasis. Key signaling mechanisms within these areas include the N-terminal variant of transient receptor potential vannilloid type-1, NaX, epithelial sodium channel, brain electroneutral transporters, and non-classical actions of vasopressin. Despite the identification of several new mechanisms, future studies need to better define the neurochemical phenotype and molecular profiles of neurons within circumventricular organs for future therapeutic potential.
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48
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In Reply to the Letter to the Editor “Circumventricular Organ Origin of Hemangioblastoama; Hypothesis for Pathogenesis of Disease”. World Neurosurg 2017; 108:983-984. [DOI: 10.1016/j.wneu.2017.09.093] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2017] [Accepted: 09/14/2017] [Indexed: 11/23/2022]
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49
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Gabriel Knoll J, Krasnow SM, Marks DL. Interleukin-1β signaling in fenestrated capillaries is sufficient to trigger sickness responses in mice. J Neuroinflammation 2017; 14:219. [PMID: 29121947 PMCID: PMC5680784 DOI: 10.1186/s12974-017-0990-7] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2017] [Accepted: 10/30/2017] [Indexed: 11/13/2023] Open
Abstract
BACKGROUND The physiological and behavioral symptoms of sickness, including fever, anorexia, behavioral depression, and weight loss can be both beneficial and detrimental. These sickness responses are triggered by pro-inflammatory cytokines acting on cells within the brain. Previous research demonstrates that the febrile response to peripheral insults depends upon prostaglandin production by vascular endothelial cells, but the mechanisms and specific cell type(s) responsible for other sickness responses remain unknown. The purpose of the present study was to identify which cells within the brain are required for sickness responses triggered by central nervous system inflammation. METHODS Intracerebroventricular (ICV) administration of 10 ng of the potent pro-inflammatory cytokine interleukin-1β (IL-1β) was used as an experimental model of central nervous system cytokine production. We examined which cells respond to IL-1β in vivo via fluorescent immunohistochemistry. Using multiple transgenic mouse lines expressing Cre recombinase under the control of cell-specific promoters, we eliminated IL-1β signaling from different populations of cells. Food consumption, body weight, movement, and temperature were recorded in adult male mice and analyzed by two-factor ANOVA to determine where IL-1β signaling is essential for sickness responses. RESULTS Endothelial cells, microglia, ependymal cells, and astrocytes exhibit nuclear translocation of NF-κB (nuclear factor kappa-light-chain-enhancer of activated B cells) in response to IL-1β. Interfering with IL-1β signaling in microglia, endothelial cells within the parenchyma of the brain, or both did not affect sickness responses. Only mice that lacked IL-1β signaling in all endothelium including fenestrated capillaries lacked sickness responses. CONCLUSIONS These experiments show that IL-1β-induced sickness responses depend on intact IL-1β signaling in blood vessels and suggest that fenestrated capillaries act as a critical signaling relay between the immune and nervous systems. TRIAL REGISTRATION Not applicable.
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Affiliation(s)
- J. Gabriel Knoll
- Department of Pediatrics, Papé Family Pediatric Research Institute, Oregon Health & Science University, Mail Code L481 3181 SW Sam Jackson Park Rd, Portland, OR 97239 USA
| | - Stephanie M. Krasnow
- Department of Pediatrics, Papé Family Pediatric Research Institute, Oregon Health & Science University, Mail Code L481 3181 SW Sam Jackson Park Rd, Portland, OR 97239 USA
| | - Daniel L. Marks
- Department of Pediatrics, Papé Family Pediatric Research Institute, Oregon Health & Science University, Mail Code L481 3181 SW Sam Jackson Park Rd, Portland, OR 97239 USA
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50
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Takagi S, Furube E, Nakano Y, Morita M, Miyata S. Microglia are continuously activated in the circumventricular organs of mouse brain. J Neuroimmunol 2017; 331:74-86. [PMID: 29107327 DOI: 10.1016/j.jneuroim.2017.10.008] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2017] [Revised: 10/13/2017] [Accepted: 10/13/2017] [Indexed: 12/11/2022]
Abstract
Microglia are the primary resident immune cells of the brain parenchyma and transform into the amoeboid form in the "activated state" under pathological conditions from the ramified form in the "resting state" under physiologically healthy conditions. In the present study, we found that microglia in the circumventricular organs (CVOs) of adult mice displayed the amoeboid form with fewer branched cellular processes even under normal conditions; however, those in other brain regions showed the ramified form, which is characterized by well-branched and dendritic cellular processes. Moreover, microglia in the CVOs showed the strong protein expression of the M1 markers CD16/32 and CD86 and M2 markers CD206 and Ym1 without any pathological stimulation. Thus, the present results indicate that microglia in the CVOs of adult mice are morphologically and functionally activated under normal conditions, possibly due to the specialized features of the CVOs, namely, the entry of blood-derived molecules into parenchyma through fenestrated capillaries and the presence of neural stem cells.
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Affiliation(s)
- Shohei Takagi
- Department of Applied Biology, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 606-8585, Japan
| | - Eriko Furube
- Department of Applied Biology, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 606-8585, Japan
| | - Yousuke Nakano
- Department of Applied Biology, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 606-8585, Japan; Department of Anatomy and Brain Science, Kansai Medical University, Hirakata, Japan
| | - Mitsuhiro Morita
- Department of Biology, Graduate School of Science, Kobe University, Kobe, Japan
| | - Seiji Miyata
- Department of Applied Biology, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 606-8585, Japan.
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