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Epel B, Viswakarma N, Hameed S, Freidin MM, Abrams CK, Kotecha M. Assessment of blood-brain barrier leakage and brain oxygenation in Connexin-32 knockout mice with systemic neuroinflammation using pulse electron paramagnetic resonance imaging techniques. Magn Reson Med 2024; 91:2519-2531. [PMID: 38193348 PMCID: PMC10997480 DOI: 10.1002/mrm.29994] [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: 08/11/2023] [Revised: 11/30/2023] [Accepted: 12/13/2023] [Indexed: 01/10/2024]
Abstract
PURPOSE The determination of blood-brain barrier (BBB) integrity and partial pressure of oxygen (pO2) in the brain is of substantial interest in several neurological applications. This study aimed to assess the feasibility of using trityl OX071-based pulse electron paramagnetic resonance imaging (pEPRI) to provide a quantitative estimate of BBB integrity and pO2 maps in mouse brains as a function of neuroinflammatory disease progression. METHODS Five Connexin-32 (Cx32)-knockout (KO) mice were injected with lipopolysaccharide to induce neuroinflammation for imaging. Three wild-type mice were also used to optimize the imaging procedure and as control animals. An additional seven Cx32-KO mice were used to establish the BBB leakage of trityl using the colorimetric assay. All pEPRI experiments were performed using a preclinical instrument, JIVA-25 (25 mT/720 MHz), at times t = 0, 4, and 6 h following lipopolysaccharide injection. Two pEPRI imaging techniques were used: (a) single-point imaging for obtaining spatial maps to outline the brain and calculate BBB leakage using the signal amplitude, and (b) inversion-recovery electron spin echo for obtaining pO2 maps. RESULTS A statistically significant change in BBB leakage was found using pEPRI with the progression of inflammation in Cx32 KO animals. However, the change in pO2 values with the progression of inflammation for these animals was not statistically significant. CONCLUSIONS For the first time, we show the ability of pEPRI to provide pO2 maps in mouse brains noninvasively, along with a quantitative assessment of BBB leakage. We expect this study to open new queries from the field to explore the pathology of many neurological diseases and provide a path to new treatments.
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Affiliation(s)
- Boris Epel
- Oxygen Measurement Core, O2M Technologies, LLC, Chicago, Illinois, USA
- Department of Radiation and Cellular Oncology, The University of Chicago, Chicago, Illinois, USA
| | - Navin Viswakarma
- Oxygen Measurement Core, O2M Technologies, LLC, Chicago, Illinois, USA
| | - Safa Hameed
- Oxygen Measurement Core, O2M Technologies, LLC, Chicago, Illinois, USA
| | - Mona M Freidin
- Department of Neurology and Rehabilitation, University of Illinois at Chicago, Chicago, Illinois, USA
| | - Charles K Abrams
- Department of Neurology and Rehabilitation, University of Illinois at Chicago, Chicago, Illinois, USA
- Richard and Loan Hill Department of Biomedical Engineering, University of Illinois at Chicago, Chicago, Illinois, USA
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Takase EO, Yamasaki R, Nagata S, Watanabe M, Masaki K, Yamaguchi H, Kira JI, Takeuchi H, Isobe N. Astroglial connexin 43 is a novel therapeutic target for chronic multiple sclerosis model. Sci Rep 2024; 14:10877. [PMID: 38740862 DOI: 10.1038/s41598-024-61508-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2023] [Accepted: 05/07/2024] [Indexed: 05/16/2024] Open
Abstract
In chronic stages of multiple sclerosis (MS) and its animal model, experimental autoimmune encephalitis (EAE), connexin (Cx)43 gap junction channel proteins are overexpressed because of astrogliosis. To elucidate the role of increased Cx43, the central nervous system (CNS)-permeable Cx blocker INI-0602 was therapeutically administered. C57BL6 mice with chronic EAE initiated by MOG35-55 received INI-0602 (40 mg/kg) or saline intraperitoneally every other day from days post-immunization (dpi) 17-50. Primary astroglia were employed to observe calcein efflux responses. In INI-0602-treated mice, EAE clinical signs improved significantly in the chronic phase, with reduced demyelination and decreased CD3+ T cells, Iba-1+ and F4/80+ microglia/macrophages, and C3+GFAP+ reactive astroglia infiltration in spinal cord lesions. Flow cytometry analysis of CD4+ T cells from CNS tissues revealed significantly reduced Th17 and Th17/Th1 cells (dpi 24) and Th1 cells (dpi 50). Multiplex array of cerebrospinal fluid showed significantly suppressed IL-6 and significantly increased IL-10 on dpi 24 in INI-0602-treated mice, and significantly suppressed IFN-γ and MCP-1 on dpi 50 in the same group. In vitro INI-0602 treatment inhibited ATP-induced calcium propagations of Cx43+/+ astroglial cells to similar levels of those of Cx43-/- cells. Astroglial Cx43 hemichannels represent a novel therapeutic target for chronic EAE and MS.
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Affiliation(s)
- Ezgi Ozdemir Takase
- Department of Neurology, Neurological Institute, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan
| | - Ryo Yamasaki
- Department of Neurology, Neurological Institute, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan.
| | - Satoshi Nagata
- Department of Neurology, Neurological Institute, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan
| | - Mitsuru Watanabe
- Department of Neurology, Neurological Institute, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan
| | - Katsuhisa Masaki
- Department of Neurology, Neurological Institute, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan
| | - Hiroo Yamaguchi
- School of Physical Therapy, Faculty of Rehabilitation, Reiwa Health Sciences University, Fukuoka, Japan
| | - Jun-Ichi Kira
- Translational Neuroscience Center, Graduate School of Medicine, and School of Pharmacy at Fukuoka, International University of Health and Welfare, Ookawa, Japan
- Department of Neurology, Brain and Nerve Center, Fukuoka Central Hospital, Fukuoka, Japan
| | - Hideyuki Takeuchi
- Department of Neurology and Stroke Medicine, Graduate School of Medicine, Yokohama City University, 3-9 Fukuura, Kanazawa-ku, Yokohama, 236-0004, Japan.
- Department of Neurology, Graduate School of Medicine, International University of Health and Welfare, Narita, Japan.
- Center for Intractable Neurological Diseases and Dementia, International University of Health and Welfare Atami Hospital, Atami, Japan.
| | - Noriko Isobe
- Department of Neurology, Neurological Institute, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan
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Li Z, Jiang YY, Long C, Peng X, Tao J, Pu Y, Yue R. Bridging metabolic syndrome and cognitive dysfunction: role of astrocytes. Front Endocrinol (Lausanne) 2024; 15:1393253. [PMID: 38800473 PMCID: PMC11116704 DOI: 10.3389/fendo.2024.1393253] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/28/2024] [Accepted: 04/25/2024] [Indexed: 05/29/2024] Open
Abstract
Metabolic syndrome (MetS) and cognitive dysfunction pose significant challenges to global health and the economy. Systemic inflammation, endocrine disruption, and autoregulatory impairment drive neurodegeneration and microcirculatory damage in MetS. Due to their unique anatomy and function, astrocytes sense and integrate multiple metabolic signals, including peripheral endocrine hormones and nutrients. Astrocytes and synapses engage in a complex dialogue of energetic and immunological interactions. Astrocytes act as a bridge between MetS and cognitive dysfunction, undergoing diverse activation in response to metabolic dysfunction. This article summarizes the alterations in astrocyte phenotypic characteristics across multiple pathological factors in MetS. It also discusses the clinical value of astrocytes as a critical pathologic diagnostic marker and potential therapeutic target for MetS-associated cognitive dysfunction.
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Affiliation(s)
- Zihan Li
- Department of Endocrinology, Hospital of Chengdu University of Traditional Chinese Medicine, Chengdu, China
- Clinical Medical School, Chengdu University of Traditional Chinese Medicine, Chengdu, China
| | - Ya-yi Jiang
- Department of Endocrinology, Hospital of Chengdu University of Traditional Chinese Medicine, Chengdu, China
- Clinical Medical School, Chengdu University of Traditional Chinese Medicine, Chengdu, China
| | - Caiyi Long
- Department of Endocrinology, Hospital of Chengdu University of Traditional Chinese Medicine, Chengdu, China
- Clinical Medical School, Chengdu University of Traditional Chinese Medicine, Chengdu, China
| | - Xi Peng
- Department of Endocrinology, Hospital of Chengdu University of Traditional Chinese Medicine, Chengdu, China
- Clinical Medical School, Chengdu University of Traditional Chinese Medicine, Chengdu, China
| | - Jiajing Tao
- Department of Endocrinology, Hospital of Chengdu University of Traditional Chinese Medicine, Chengdu, China
- Clinical Medical School, Chengdu University of Traditional Chinese Medicine, Chengdu, China
| | - Yueheng Pu
- Department of Endocrinology, Hospital of Chengdu University of Traditional Chinese Medicine, Chengdu, China
- Clinical Medical School, Chengdu University of Traditional Chinese Medicine, Chengdu, China
| | - Rensong Yue
- Department of Endocrinology, Hospital of Chengdu University of Traditional Chinese Medicine, Chengdu, China
- Clinical Medical School, Chengdu University of Traditional Chinese Medicine, Chengdu, China
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Faisal SM, Clewner JE, Stack B, Varela ML, Comba A, Abbud G, Motsch S, Castro MG, Lowenstein PR. Spatiotemporal Insights into Glioma Oncostream Dynamics: Unraveling Formation, Stability, and Disassembly Pathways. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2024; 11:e2309796. [PMID: 38384234 PMCID: PMC11095212 DOI: 10.1002/advs.202309796] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2023] [Revised: 02/08/2024] [Indexed: 02/23/2024]
Abstract
Glioblastoma (GBM) remains a challenge in Neuro-oncology, with a poor prognosis showing only a 5% survival rate beyond two years. This is primarily due to its aggressiveness and intra-tumoral heterogeneity, which limits complete surgical resection and reduces the efficacy of existing treatments. The existence of oncostreams-neuropathological structures comprising aligned spindle-like cells from both tumor and non-tumor origins- is discovered earlier. Oncostreams are closely linked to glioma aggressiveness and facilitate the spread into adjacent healthy brain tissue. A unique molecular signature intrinsic to oncostreams, with overexpression of key genes (i.e., COL1A1, ACTA2) that drive the tumor's mesenchymal transition and malignancy is also identified. Pre-clinical studies on genetically engineered mouse models demonstrated that COL1A1 inhibition disrupts oncostreams, modifies TME, reduces mesenchymal gene expression, and extends survival. An in vitro model using GFP+ NPA cells to investigate how various treatments affect oncostream dynamics is developed. Analysis showed that factors such as cell density, morphology, neurotransmitter agonists, calcium chelators, and cytoskeleton-targeting drugs influence oncostream formation. This data illuminate the patterns of glioma migration and suggest anti-invasion strategies that can improve GBM patient outcomes when combined with traditional therapies. This work highlights the potential of targeting oncostreams to control glioma invasion and enhance treatment efficacy.
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Affiliation(s)
- Syed M. Faisal
- Department of NeurosurgeryUniversity of Michigan Medical SchoolAnn ArborMichigan48108USA
- Department of Cell and Developmental BiologyUniversity of Michigan Medical SchoolAnn ArborMichigan48108USA
- Rogel Cancer CentreUniversity of Michigan Medical SchoolAnn ArborMichigan48108USA
| | - Jarred E. Clewner
- Department of NeurosurgeryUniversity of Michigan Medical SchoolAnn ArborMichigan48108USA
- Department of Cell and Developmental BiologyUniversity of Michigan Medical SchoolAnn ArborMichigan48108USA
- Rogel Cancer CentreUniversity of Michigan Medical SchoolAnn ArborMichigan48108USA
| | - Brooklyn Stack
- Department of NeurosurgeryUniversity of Michigan Medical SchoolAnn ArborMichigan48108USA
- Department of Cell and Developmental BiologyUniversity of Michigan Medical SchoolAnn ArborMichigan48108USA
- Rogel Cancer CentreUniversity of Michigan Medical SchoolAnn ArborMichigan48108USA
| | - Maria L. Varela
- Department of NeurosurgeryUniversity of Michigan Medical SchoolAnn ArborMichigan48108USA
- Department of Cell and Developmental BiologyUniversity of Michigan Medical SchoolAnn ArborMichigan48108USA
- Rogel Cancer CentreUniversity of Michigan Medical SchoolAnn ArborMichigan48108USA
| | - Andrea Comba
- Department of NeurosurgeryUniversity of Michigan Medical SchoolAnn ArborMichigan48108USA
- Department of Cell and Developmental BiologyUniversity of Michigan Medical SchoolAnn ArborMichigan48108USA
- Rogel Cancer CentreUniversity of Michigan Medical SchoolAnn ArborMichigan48108USA
| | - Grace Abbud
- Department of NeurosurgeryUniversity of Michigan Medical SchoolAnn ArborMichigan48108USA
- Department of Cell and Developmental BiologyUniversity of Michigan Medical SchoolAnn ArborMichigan48108USA
- Rogel Cancer CentreUniversity of Michigan Medical SchoolAnn ArborMichigan48108USA
| | - Sebastien Motsch
- Department of Statistics and Mathematical SciencesArizona State UniversityTempeArizona85287USA
| | - Maria G. Castro
- Department of NeurosurgeryUniversity of Michigan Medical SchoolAnn ArborMichigan48108USA
- Department of Cell and Developmental BiologyUniversity of Michigan Medical SchoolAnn ArborMichigan48108USA
- Rogel Cancer CentreUniversity of Michigan Medical SchoolAnn ArborMichigan48108USA
| | - Pedro R. Lowenstein
- Department of NeurosurgeryUniversity of Michigan Medical SchoolAnn ArborMichigan48108USA
- Department of Cell and Developmental BiologyUniversity of Michigan Medical SchoolAnn ArborMichigan48108USA
- Rogel Cancer CentreUniversity of Michigan Medical SchoolAnn ArborMichigan48108USA
- Department of Biomedical EngineeringUniversity of Michigan Medical SchoolAnn ArborMichigan48108USA
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Tao S, Hulpiau P, Wagner LE, Witschas K, Yule DI, Bultynck G, Leybaert L. IP3RPEP6, a novel peptide inhibitor of IP 3 receptor channels that does not affect connexin-43 hemichannels. Acta Physiol (Oxf) 2024; 240:e14086. [PMID: 38240350 DOI: 10.1111/apha.14086] [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: 07/20/2023] [Revised: 10/24/2023] [Accepted: 01/01/2024] [Indexed: 02/24/2024]
Abstract
AIM Inositol 1,4,5-trisphosphate receptors (IP3 Rs) are intracellular Ca2+ -release channels with crucial roles in cell function. Current IP3 R inhibitors suffer from off-target effects and poor selectivity towards the three distinct IP3 R subtypes. We developed a novel peptide inhibitor of IP3 Rs and determined its effect on connexin-43 (Cx43) hemichannels, which are co-activated by IP3 R stimulation. METHODS IP3RPEP6 was developed by in silico molecular docking studies and characterized by on-nucleus patch-clamp experiments of IP3 R2 channels and carbachol-induced IP3 -mediated Ca2+ responses in IP3 R1, 2 or 3 expressing cells, triple IP3 R KO cells and astrocytes. Cx43 hemichannels were studied by patch-clamp and ATP-release approaches, and by inhibition with Gap19 peptide. IP3RPEP6 interactions with IP3 Rs were verified by co-immunoprecipitation and affinity pull-down assays. RESULTS IP3RPEP6 concentration-dependently reduced the open probability of IP3 R2 channels and competitively inhibited IP3 Rs in an IC50 order of IP3 R2 (~3.9 μM) < IP3 R3 (~4.3 μM) < IP3 R1 (~9.0 μM), without affecting Cx43 hemichannels or ryanodine receptors. IP3RPEP6 co-immunoprecipitated with IP3 R2 but not with IP3 R1; interaction with IP3 R3 varied between cell types. The IC50 of IP3RPEP6 inhibition of carbachol-induced Ca2+ responses decreased with increasing cellular Cx43 expression. Moreover, Gap19-inhibition of Cx43 hemichannels significantly reduced the amplitude of the IP3 -Ca2+ responses and strongly increased the EC50 of these responses. Finally, we identified palmitoyl-8G-IP3RPEP6 as a membrane-permeable IP3RPEP6 version allowing extracellular application of the IP3 R-inhibiting peptide. CONCLUSION IP3RPEP6 inhibits IP3 R2/R3 at concentrations that have limited effects on IP3 R1. IP3 R activation triggers hemichannel opening, which strongly affects the amplitude and concentration-dependence of IP3 -triggered Ca2+ responses.
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Affiliation(s)
- Siyu Tao
- Department of Basic and Applied Medical Sciences-Physiology Group, Ghent University, Ghent, Belgium
| | - Paco Hulpiau
- Department of Bio-Medical Sciences, HOWEST University of Applied Sciences (Hogeschool West-Vlaanderen), Bruges, Belgium
| | - Larry E Wagner
- Department of Pharmacology and Physiology, School of Medicine and Dentistry, University of Rochester Medical Center, Rochester, New York, USA
| | - Katja Witschas
- Department of Basic and Applied Medical Sciences-Physiology Group, Ghent University, Ghent, Belgium
| | - David I Yule
- Department of Pharmacology and Physiology, School of Medicine and Dentistry, University of Rochester Medical Center, Rochester, New York, USA
| | - Geert Bultynck
- Laboratory of Molecular and Cellular Signaling, Department of Molecular Cell Biology, KU Leuven, Leuven, Belgium
| | - Luc Leybaert
- Department of Basic and Applied Medical Sciences-Physiology Group, Ghent University, Ghent, Belgium
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Chumak T, Jullienne A, Joakim Ek C, Ardalan M, Svedin P, Quan R, Salehi A, Salari S, Obenaus A, Vexler ZS, Mallard C. Maternal n-3 enriched diet reprograms neurovascular transcriptome and blunts inflammation in neonate. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.22.576634. [PMID: 38328227 PMCID: PMC10849562 DOI: 10.1101/2024.01.22.576634] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/09/2024]
Abstract
Infection during perinatal period can adversely affect brain development, predispose infants to ischemic stroke and have lifelong consequences. We previously demonstrated that diet enriched in n-3 polyunsaturated fatty acids (PUFA) transforms brain lipid composition and protects from neonatal stroke. Vasculature is a critical interface between blood and brain providing a barrier to systemic infection. Here we examined whether maternal PUFA-enriched diets exert reprograming of endothelial cell signalling in 9-day old mice after endotoxin (LPS)-induced infection. Transcriptome analysis was performed on brain microvessels from pups born to dams maintained on 3 diets: standard, n-3 or n-6 enriched. N-3 diet enabled higher immune reactivity in brain vasculature, while preventing imbalance of cell cycle regulation and extracellular matrix cascades that accompanied inflammatory response in standard diet. LPS response in blood and brain was blunted in n-3 offspring. Cerebral angioarchitecture analysis revealed modified vessel complexity after LPS. Thus, n-3-enriched maternal diet partially prevents imbalance in homeostatic processes and alters inflammation rather than affects brain vascularization during early life. Importantly, maternal diet may presage offspring neurovascular outcomes later in life.
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Wu BA, Chand KK, Bell A, Miller SL, Colditz PB, Malhotra A, Wixey JA. Effects of fetal growth restriction on the perinatal neurovascular unit and possible treatment targets. Pediatr Res 2024; 95:59-69. [PMID: 37674023 PMCID: PMC10798895 DOI: 10.1038/s41390-023-02805-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/01/2023] [Revised: 08/04/2023] [Accepted: 08/16/2023] [Indexed: 09/08/2023]
Abstract
The neurovascular unit (NVU) within the brain is a multicellular unit that synergistically acts to maintain blood-brain barrier function and meet cerebral metabolic demand. Recent studies have indicated disruption to the NVU is associated with neuropathology in the perinatal brain. Infants with fetal growth restriction (FGR) are known to be at increased risk of neurodevelopmental conditions including motor, learning, and behavioural deficits. There are currently no neuroprotective treatments for these conditions. In this review, we analyse large animal studies examining the effects of FGR on the perinatal NVU. These studies show altered vascularity in the FGR brain as well as blood-brain barrier dysfunction due to underlying cellular changes, mediated by neuroinflammation. Neuroinflammation is a key mechanism associated with pathological effects in the FGR brain. Hence, targeting inflammation may be key to preserving the multicellular NVU and providing neuroprotection in FGR. A number of maternal and postnatal therapies with anti-inflammatory components have been investigated in FGR animal models examining targets for amelioration of NVU disruption. Each therapy showed promise by uniquely ameliorating the adverse effects of FGR on multiple aspects of the NVU. The successful implementation of a clinically viable neuroprotective treatment has the potential to improve outcomes for neonates affected by FGR. IMPACT: Disruption to the neurovascular unit is associated with neuropathology in fetal growth restriction. Inflammation is a key mechanism associated with neurovascular unit disruption in the growth-restricted brain. Anti-inflammatory treatments ameliorate adverse effects on the neurovascular unit and may provide neuroprotection.
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Affiliation(s)
- Bing Anthony Wu
- Department of Paediatrics, Monash University, Melbourne, VIC, Australia
| | - Kirat K Chand
- UQ Centre for Clinical Research, Faculty of Medicine, The University of Queensland, Brisbane, QLD, Australia
| | - Alexander Bell
- Department of Obstetrics and Gynaecology, Monash University, Melbourne, VIC, Australia
- The Ritchie Centre, Hudson Institute of Medical Research, Melbourne, VIC, Australia
| | - Suzanne L Miller
- Department of Obstetrics and Gynaecology, Monash University, Melbourne, VIC, Australia
- The Ritchie Centre, Hudson Institute of Medical Research, Melbourne, VIC, Australia
| | - Paul B Colditz
- UQ Centre for Clinical Research, Faculty of Medicine, The University of Queensland, Brisbane, QLD, Australia
- Perinatal Research Centre, Royal Brisbane and Women's Hospital, Brisbane, QLD, Australia
| | - Atul Malhotra
- Department of Paediatrics, Monash University, Melbourne, VIC, Australia
- The Ritchie Centre, Hudson Institute of Medical Research, Melbourne, VIC, Australia
- Monash Newborn, Monash Children's Hospital, Melbourne, VIC, Australia
| | - Julie A Wixey
- UQ Centre for Clinical Research, Faculty of Medicine, The University of Queensland, Brisbane, QLD, Australia.
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Schumacher S, Tahiri H, Ezan P, Rouach N, Witschas K, Leybaert L. Inhibiting astrocyte connexin-43 hemichannels blocks radiation-induced vesicular VEGF-A release and blood-brain barrier dysfunction. Glia 2024; 72:34-50. [PMID: 37670489 DOI: 10.1002/glia.24460] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2023] [Revised: 07/28/2023] [Accepted: 08/09/2023] [Indexed: 09/07/2023]
Abstract
Therapeutic brain irradiation with ionizing radiation exerts multiple side effects including barrier leakage that disturbs glial-neuronal functioning and may affect cognition. Astrocytes contribute to barrier leakage by endfeet release of various vasoactive substances acting on capillary endothelial cells forming the barrier. Here, we investigated X-ray effects on astrocytic vesicular transport in mice and determined whether interfering with astrocyte connexins affects radiation-induced barrier leakage. We found that astrocytic VEGF-A-loaded VAMP3 vesicles drastically reorganize starting from 6 h post-irradiation and move in a calcium- and Cx43-dependent manner towards endfeet where VEGF-A is released, provoking barrier leakage. Vesicular transport activation, VEGF-A release and leakage 24 h post-irradiation were all potently inhibited by astrocytic Cx43 KO, Cx43S255/262/279/282A (MK4) mutant mice and TATGap19 inhibition of Cx43 hemichannel opening. Astrocyte VEGF release is a major player in complications of brain irradiation, which can be mitigated by anti-VEGF treatments. Targeting Cx43 hemichannels allows to prevent astrocyte VEGF release at an early stage after brain irradiation.
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Affiliation(s)
- Steffi Schumacher
- Department of Basic and Applied Medical Sciences - Physiology Group, Ghent University, Ghent, Belgium
| | - Hanane Tahiri
- Department of Basic and Applied Medical Sciences - Physiology Group, Ghent University, Ghent, Belgium
| | - Pascal Ezan
- Center for Interdisciplinary Research in Biology, Collège de France, CNRS, INSERM, Université PSL, Labex Memolife, Paris, France
| | - Nathalie Rouach
- Center for Interdisciplinary Research in Biology, Collège de France, CNRS, INSERM, Université PSL, Labex Memolife, Paris, France
| | - Katja Witschas
- Department of Basic and Applied Medical Sciences - Physiology Group, Ghent University, Ghent, Belgium
| | - Luc Leybaert
- Department of Basic and Applied Medical Sciences - Physiology Group, Ghent University, Ghent, Belgium
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Estudillo E, López-Ornelas A, Rodríguez-Oviedo A, Gutiérrez de la Cruz N, Vargas-Hernández MA, Jiménez A. Thinking outside the black box: are the brain endothelial cells the new main target in Alzheimer's disease? Neural Regen Res 2023; 18:2592-2598. [PMID: 37449594 DOI: 10.4103/1673-5374.373672] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/18/2023] Open
Abstract
The blood-brain barrier is the interface through which the brain interacts with the milieu and consists mainly of a sophisticated network of brain endothelial cells that forms blood vessels and selectively moves molecules inside and outside the brain through multiple mechanisms of transport. Although brain endothelial cell function is crucial for brain homeostasis, their role in neurodegenerative diseases has historically not been considered with the same importance as other brain cells such as microglia, astroglia, neurons, or even molecules such as amyloid beta, Tau, or alpha-synuclein. Alzheimer's disease is the most common neurodegenerative disease, and brain endothelial cell dysfunction has been reported by several groups. However, its impairment has barely been considered as a potential therapeutic target. Here we review the most recent advances in the relationship between Alzheimer's disease and brain endothelial cells commitment and analyze the possible mechanisms through which their alterations contribute to this neurodegenerative disease, highlighting their inflammatory phenotype and the possibility of an impaired secretory pattern of brain endothelial cells that could contribute to the progression of this ailment. Finally, we discuss why shall brain endothelial cells be appreciated as a therapeutic target instead of solely an obstacle for delivering treatments to the injured brain in Alzheimer's disease.
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Affiliation(s)
- Enrique Estudillo
- Laboratorio de Reprogramación Celular, Instituto Nacional de Neurología y Neurocirugía Manuel Velasco Suárez, Mexico City, Mexico
| | - Adolfo López-Ornelas
- División de Investigación, Hospital Juárez de México; Hospital Nacional Homeopático, Hospitales Federales de Referencia, Mexico City, Mexico
| | | | - Neptali Gutiérrez de la Cruz
- Laboratorio de Morfología; Escuela Militar de Graduados de Sanidad, Secretaría de la Defensa Nacional, Batalla de Celaya, Lomas de Sotelo, Miguel Hidalgo, Mexico City, Mexico
| | - Marco Antonio Vargas-Hernández
- Escuela Militar de Graduados de Sanidad, Secretaría de la Defensa Nacional, Batalla de Celaya, Lomas de Sotelo, Miguel Hidalgo, Mexico City, Mexico
| | - Adriana Jiménez
- División de Investigación, Hospital Juárez de México, Mexico City, Mexico
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10
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Yamasaki R. Connexins Control Glial Inflammation in Various Neurological Diseases. Int J Mol Sci 2023; 24:16879. [PMID: 38069203 PMCID: PMC10706219 DOI: 10.3390/ijms242316879] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2023] [Revised: 11/25/2023] [Accepted: 11/27/2023] [Indexed: 12/18/2023] Open
Abstract
Connexins (Cxs) form gap junctions through homotypic/heterotypic oligomerization. Cxs are initially synthesized in the endoplasmic reticulum, then assembled as hexamers in the Golgi apparatus before being integrated into the cell membrane as hemichannels. These hemichannels remain closed until they combine to create gap junctions, directly connecting neighboring cells. Changes in the intracellular or extracellular environment are believed to trigger the opening of hemichannels, creating a passage between the inside and outside of the cell. The size of the channel pore depends on the Cx isoform and cellular context-specific effects such as posttranslational modifications. Hemichannels allow various bioactive molecules, under ~1 kDa, to move in and out of the host cell in the direction of the electrochemical gradient. In this review, we explore the fundamental roles of Cxs and their clinical implications in various neurological dysfunctions, including hereditary diseases, ischemic brain disorders, degenerative conditions, demyelinating disorders, and psychiatric illnesses. The influence of Cxs on the pathomechanisms of different neurological disorders varies depending on the circumstances. Hemichannels are hypothesized to contribute to proinflammatory effects by releasing ATP, adenosine, glutamate, and other bioactive molecules, leading to neuroglial inflammation. Modulating Cxs' hemichannels has emerged as a promising therapeutic approach.
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Affiliation(s)
- Ryo Yamasaki
- Department of Neurology, Neurological Institute, Graduate School of Medical Sciences, Kyushu University, Fukuoka 812-8582, Japan
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Santana-Coelho D, Lugo JN. Hippocampal Upregulation of Complement Component C3 in Response to Lipopolysaccharide Stimuli in a Model of Fragile-X Syndrome. Curr Issues Mol Biol 2023; 45:9306-9315. [PMID: 37998759 PMCID: PMC10669955 DOI: 10.3390/cimb45110582] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2023] [Revised: 11/09/2023] [Accepted: 11/17/2023] [Indexed: 11/25/2023] Open
Abstract
The complement system is part of the innate immune system and has been shown to be altered in autism spectrum disorder (ASD). Fragile-X syndrome (FXS) is the main genetic cause of ASD and studies suggest a dysregulation in the immune system in patients with the disorder. To assess if an animal model of FXS presents with altered complement signaling, we treated male Fmr1 knockout (KO) mice with lipopolysaccharide (LPS) and collected the hippocampus 24 h later. Assessment of the expression of the complement genes C1q, C3, and C4 identified the upregulation of C3 in both wild-type (WT) and knockout mice. Levels of C3 also increased in both genotypes. Analysis of the correlation between the expression of C3 and the cytokines IL-6, IL-1β, and TNF-α identified a different relationship between the expression of the genes in Fmr1 KO when compared to WT mice. Our findings did not support our initial hypotheses that the lack of the FMR1 gene would alter complement system signaling, and that the induction of the complement system in response to LPS in Fmr1 KO mice differed from wild-type conspecifics.
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Affiliation(s)
| | - Joaquin N. Lugo
- Department of Psychology and Neuroscience, Baylor University, Waco, TX 76798, USA;
- Institute of Biomedical Studies, Baylor University, Waco, TX 76798, USA
- Department of Biology, Baylor University, Waco, TX 76798, USA
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Espinoza H, Figueroa XF. Opening of Cx43-formed hemichannels mediates the Ca 2+ signaling associated with endothelial cell migration. Biol Direct 2023; 18:52. [PMID: 37635249 PMCID: PMC10463847 DOI: 10.1186/s13062-023-00408-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2023] [Accepted: 08/19/2023] [Indexed: 08/29/2023] Open
Abstract
Endothelial cell migration is a key process in angiogenesis. Progress of endothelial cell migration is orchestrated by coordinated generation of Ca2+ signals through a mechanism organized in caveolar microdomains. Connexins (Cx) play a central role in coordination of endothelial cell function, directly by cell-to-cell communication via gap junction and, indirectly, by the release of autocrine/paracrine signals through Cx-formed hemichannels. However, Cx hemichannels are also permeable to Ca2+ and Cx43 can be associated with caveolin-1, a structural protein of caveolae. We proposed that endothelial cell migration relies on Cx43 hemichannel opening. Here we show a novel mechanism of Ca2+ signaling in endothelial cell migration. The Ca2+ signaling that mediates endothelial cell migration and the subsequent tubular structure formation depended on Cx43 hemichannel opening and is associated with the translocation of Cx43 with caveolae to the rear part of the cells. These findings indicate that Cx43 hemichannels play a central role in endothelial cell migration and provide new therapeutic targets for the control of deregulated angiogenesis in pathological conditions such as cancer.
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Affiliation(s)
- Hilda Espinoza
- Departamento de Fisiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, 8330025, Chile
- Escuela de Medicina, Facultad de Ciencias de la Salud, Universidad del Alba, Santiago, 8370007, Chile
| | - Xavier F Figueroa
- Departamento de Fisiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, 8330025, Chile.
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Keep RF, Jones HC, Hamilton MG, Drewes LR. A year in review: brain barriers and brain fluids research in 2022. Fluids Barriers CNS 2023; 20:30. [PMID: 37085841 PMCID: PMC10120509 DOI: 10.1186/s12987-023-00429-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2023] [Indexed: 04/23/2023] Open
Abstract
This aim of this editorial is to highlight progress made in brain barrier and brain fluid research in 2022. It covers studies on the blood-brain, blood-retina and blood-CSF barriers (choroid plexus and meninges), signaling within the neurovascular unit and elements of the brain fluid systems. It further discusses how brain barriers and brain fluid systems are impacted in CNS diseases, their role in disease progression and progress being made in treating such diseases.
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Affiliation(s)
- Richard F Keep
- Department of Neurosurgery, University of Michigan, R5018 BSRB 109 Zina Pitcher Place, Ann Arbor, MI, 48109-2200, USA.
| | | | - Mark G Hamilton
- Department of Clinical Neurosciences, Division of Neurosurgery, University of Calgary, Alberta, Canada
| | - Lester R Drewes
- Department of Biomedical Sciences, University of Minnesota Medical School Duluth, Duluth, MN, 55812, USA
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