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Koga M, Sato M, Nakagawa R, Tokuno S, Asai F, Maezawa Y, Nagamine M, Yoshino A, Toda H. Molecular hydrogen supplementation in mice ameliorates lipopolysaccharide-induced loss of interest. PCN REPORTS : PSYCHIATRY AND CLINICAL NEUROSCIENCES 2024; 3:e70000. [PMID: 39171191 PMCID: PMC11337204 DOI: 10.1002/pcn5.70000] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/03/2024] [Revised: 07/15/2024] [Accepted: 08/05/2024] [Indexed: 08/23/2024]
Abstract
Aim The objective of this study was to evaluate the potential of hydrogen in preventing and treating psychiatric symptoms, particularly depressed mood and loss of interest, and to explore its underlying mechanisms. A mouse model exhibiting inflammation-derived depressive symptoms was used for the investigation. Methods Institute of Cancer Research mice were subjected to a 7-day intervention of either 30% hydrogen or 40 g per day of air via jelly intake. On the final day, lipopolysaccharide (LPS) was intraperitoneally administered at 5 mg/kg to induce inflammation-related depressive symptoms. Behavioral and biochemical assessments were conducted 24 h post-LPS administration. Results Following LPS administration, a decrease in spontaneous behavior was observed; however, this effect was mitigated in the group treated with hydrogen. The social interaction test revealed a significant reduction in interactions with unfamiliar mice in the LPS-treated group, whereas the hydrogen-treated group exhibited no such decrease. No significant changes were noted in the forced-swim test for either group. Additionally, the administration of LPS in the hydrogen group did not result in a decrease in zonula occludens-1, a biochemical marker associated with barrier function at the cerebrovascular barrier and expressed in tight junctions. Conclusion Hydrogen administration demonstrated a preventive effect against the LPS-induced loss of interest, suggesting a potential role in symptom prevention. However, it did not exhibit a suppressive effect on depressive symptoms in this particular model. These findings highlight the nuanced impact of hydrogen in the context of inflammation-induced psychiatric symptoms, indicating potential avenues for further exploration and research.
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Affiliation(s)
- Minori Koga
- Department of Psychiatry, School of MedicineNational Defense Medical CollegeSaitamaJapan
| | - Mayumi Sato
- Department of Psychiatry, School of MedicineNational Defense Medical CollegeSaitamaJapan
| | - Ryuichi Nakagawa
- Department of Psychiatry, School of MedicineNational Defense Medical CollegeSaitamaJapan
| | - Shinichi Tokuno
- Graduate School of Health InnovationKanagawa University of Human ServicesKanagawaJapan
- Department of BioengineeringGraduate School of EngineeringTokyoJapan
| | - Fumiho Asai
- Department of Psychiatry, School of MedicineNational Defense Medical CollegeSaitamaJapan
| | - Yuri Maezawa
- Department of Psychiatry, School of MedicineNational Defense Medical CollegeSaitamaJapan
| | - Masanori Nagamine
- Division of Behavioral SciencesNational Defense Medical College Research InstituteSaitamaJapan
| | - Aihide Yoshino
- Department of Psychiatry, School of MedicineNational Defense Medical CollegeSaitamaJapan
| | - Hiroyuki Toda
- Department of Psychiatry, School of MedicineNational Defense Medical CollegeSaitamaJapan
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2
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Cogill SA, Lee JH, Jeon MT, Kim DG, Chang Y. Hopping the Hurdle: Strategies to Enhance the Molecular Delivery to the Brain through the Blood-Brain Barrier. Cells 2024; 13:789. [PMID: 38786013 PMCID: PMC11119906 DOI: 10.3390/cells13100789] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2023] [Revised: 04/04/2024] [Accepted: 04/30/2024] [Indexed: 05/25/2024] Open
Abstract
Modern medicine has allowed for many advances in neurological and neurodegenerative disease (ND). However, the number of patients suffering from brain diseases is ever increasing and the treatment of brain diseases remains an issue, as drug efficacy is dramatically reduced due to the existence of the unique vascular structure, namely the blood-brain barrier (BBB). Several approaches to enhance drug delivery to the brain have been investigated but many have proven to be unsuccessful due to limited transport or damage induced in the BBB. Alternative approaches to enhance molecular delivery to the brain have been revealed in recent studies through the existence of molecular delivery pathways that regulate the passage of peripheral molecules. In this review, we present recent advancements of the basic research for these delivery pathways as well as examples of promising ventures to overcome the molecular hurdles that will enhance therapeutic interventions in the brain and potentially save the lives of millions of patients.
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Affiliation(s)
- Sinnead Anne Cogill
- Dementia Research Group, Korea Brain Research Institute, Daegu 41062, Republic of Korea; (S.A.C.); (J.-H.L.); (M.-T.J.)
- Department of Brain & Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu 42988, Republic of Korea
| | - Jae-Hyeok Lee
- Dementia Research Group, Korea Brain Research Institute, Daegu 41062, Republic of Korea; (S.A.C.); (J.-H.L.); (M.-T.J.)
- Department of Bio and Brain Engineering, Korea Advanced Institute of Science Technology (KAIST), Daejeon 34141, Republic of Korea
| | - Min-Tae Jeon
- Dementia Research Group, Korea Brain Research Institute, Daegu 41062, Republic of Korea; (S.A.C.); (J.-H.L.); (M.-T.J.)
| | - Do-Geun Kim
- Dementia Research Group, Korea Brain Research Institute, Daegu 41062, Republic of Korea; (S.A.C.); (J.-H.L.); (M.-T.J.)
- Department of Brain & Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu 42988, Republic of Korea
| | - Yongmin Chang
- Department of Molecular Medicine, School of Medicine, Kyungpook National University, Daegu 41944, Republic of Korea
- Department of Radiology, Kyungpook National University Hospital, Daegu 41944, Republic of Korea
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Pinkiewicz M, Pinkiewicz M, Walecki J, Zaczyński A, Zawadzki M. Breaking Barriers in Neuro-Oncology: A Scoping Literature Review on Invasive and Non-Invasive Techniques for Blood-Brain Barrier Disruption. Cancers (Basel) 2024; 16:236. [PMID: 38201663 PMCID: PMC10778052 DOI: 10.3390/cancers16010236] [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: 12/05/2023] [Revised: 12/22/2023] [Accepted: 12/27/2023] [Indexed: 01/12/2024] Open
Abstract
The blood-brain barrier (BBB) poses a significant challenge to drug delivery for brain tumors, with most chemotherapeutics having limited permeability into non-malignant brain tissue and only restricted access to primary and metastatic brain cancers. Consequently, due to the drug's inability to effectively penetrate the BBB, outcomes following brain chemotherapy continue to be suboptimal. Several methods to open the BBB and obtain higher drug concentrations in tumors have been proposed, with the selection of the optimal method depending on the size of the targeted tumor volume, the chosen therapeutic agent, and individual patient characteristics. Herein, we aim to comprehensively describe osmotic disruption with intra-arterial drug administration, intrathecal/intraventricular administration, laser interstitial thermal therapy, convection-enhanced delivery, and ultrasound methods, including high-intensity focused and low-intensity ultrasound as well as tumor-treating fields. We explain the scientific concept behind each method, preclinical/clinical research, advantages and disadvantages, indications, and potential avenues for improvement. Given that each method has its limitations, it is unlikely that the future of BBB disruption will rely on a single method but rather on a synergistic effect of a combined approach. Disruption of the BBB with osmotic infusion or high-intensity focused ultrasound, followed by the intra-arterial delivery of drugs, is a promising approach. Real-time monitoring of drug delivery will be necessary for optimal results.
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Affiliation(s)
- Miłosz Pinkiewicz
- Faculty of Medicine, Wroclaw Medical University, 50-367 Wrocław, Poland
| | - Mateusz Pinkiewicz
- Department of Diagnostic Imaging, Mazowiecki Regional Hospital in Siedlce, 08-110 Siedlce, Poland
| | - Jerzy Walecki
- Division of Interventional Neuroradiology, Department of Radiology, The National Medical Institute of the Ministry of the Interior and Administration, 02-507 Warsaw, Poland
| | - Artur Zaczyński
- Department of Neurosurgery, The National Medical Institute of the Ministry of the Interior and Administration, 02-507 Warsaw, Poland
| | - Michał Zawadzki
- Division of Interventional Neuroradiology, Department of Radiology, The National Medical Institute of the Ministry of the Interior and Administration, 02-507 Warsaw, Poland
- Department of Radiology, Centre of Postgraduate Medical Education, 01-813 Warsaw, Poland
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4
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Cong X, Mao XD, Wu LL, Yu GY. The role and mechanism of tight junctions in the regulation of salivary gland secretion. Oral Dis 2024; 30:3-22. [PMID: 36825434 DOI: 10.1111/odi.14549] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2022] [Revised: 01/27/2023] [Accepted: 02/21/2023] [Indexed: 02/25/2023]
Abstract
Tight junctions (TJs) are cell-cell interactions that localize at the most apical portion of epithelial/endothelial cells. One of the predominant functions of TJs is to regulate material transport through paracellular pathway, which serves as a selective barrier. In recent years, the expression and function of TJs in salivary glands has attracted great interest. The characteristics of multiple salivary gland TJ proteins have been identified. During salivation, the activation of muscarinic acetylcholine receptor and transient receptor potential vanilloid subtype 1, as well as other stimuli, promote the opening of acinar TJs by inducing internalization of TJs, thereby contributing to increased paracellular permeability. Besides, endothelial TJs are also redistributed with leakage of blood vessels in cholinergic-stimulated submandibular glands. Furthermore, under pathological conditions, such as Sjögren's syndrome, diabetes mellitus, immunoglobulin G4-related sialadenitis, and autotransplantation, the integrity and barrier function of TJ complex are impaired and may contribute to hyposalivation. Moreover, in submandibular glands of Sjögren's syndrome mouse model and patients, the endothelial barrier is disrupted and involved in hyposecretion and lymphocytic infiltration. These findings enrich our understanding of the secretory mechanisms that link the importance of epithelial and endothelial TJ functions to salivation under both physiological and pathophysiological conditions.
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Affiliation(s)
- Xin Cong
- Center for Salivary Gland Diseases, Peking University School and Hospital of Stomatology & National Center of Stomatology & National Clinical Research Center for Oral Diseases & National Engineering Research Center of Oral Biomaterials and Digital Medical Devices, Beijing, China
- Department of Physiology and Pathophysiology, Peking University School of Basic Sciences, Beijing, China
| | - Xiang-Di Mao
- Center for Salivary Gland Diseases, Peking University School and Hospital of Stomatology & National Center of Stomatology & National Clinical Research Center for Oral Diseases & National Engineering Research Center of Oral Biomaterials and Digital Medical Devices, Beijing, China
- Department of Physiology and Pathophysiology, Peking University School of Basic Sciences, Beijing, China
| | - Li-Ling Wu
- Center for Salivary Gland Diseases, Peking University School and Hospital of Stomatology & National Center of Stomatology & National Clinical Research Center for Oral Diseases & National Engineering Research Center of Oral Biomaterials and Digital Medical Devices, Beijing, China
- Department of Physiology and Pathophysiology, Peking University School of Basic Sciences, Beijing, China
| | - Guang-Yan Yu
- Center for Salivary Gland Diseases, Peking University School and Hospital of Stomatology & National Center of Stomatology & National Clinical Research Center for Oral Diseases & National Engineering Research Center of Oral Biomaterials and Digital Medical Devices, Beijing, China
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Dong M, Tang M, Li W, Li S, Yi M, Liu W. Morphological and transcriptional analysis of sexual differentiation and gonadal development in a burrowing fish, the four-eyed sleeper (Bostrychus sinensis). COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY. PART D, GENOMICS & PROTEOMICS 2023; 48:101148. [PMID: 37865042 DOI: 10.1016/j.cbd.2023.101148] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2023] [Revised: 10/10/2023] [Accepted: 10/12/2023] [Indexed: 10/23/2023]
Abstract
Four-eyed sleeper (Bostrychus sinensis) is a commercially important sea water fish, and the male individuals exhibit significant advantages in somatic growth and stress resistance, so developing sex control strategy to create all-male progeny will produce higher economic value. However, little is known about the genetic background associated with sex differentiation in this species. In this study, we investigated gonadal development and uncovered critical window stages of sexual differentiation (about 2 mph), transition from proliferation to differentiation in female germ stem cells (GSCs) (2-3 mph) and male GSCs (3-4 mph). De novo transcriptome analysis revealed candidate genes and signaling pathways associated with sexual differentiation and gonadal development in four-eyed sleeper. The results showed that sox9 and zglp1 were the earliest sex-biased transcription factors during sex differentiation. Down-regulation of chemokine, cytokines-cytokine receptors and up-regulation of cellular senescence pathway might be involved in GSC differentiation. Weighted gene correlation network analysis showed that metabolic pathway and occludin were the hub signaling and gene in ovarian development, meanwhile the MAPK signaling pathways, cellular senescence pathway and ash1l (histone H3-lysine4 N-trimethyltransferase) were the hub pathways and gene in testicular development. The present work elucidated the developmental processes of sexual differentiation and gonadal development and revealed their associated revealed genes and signaling pathways in four-eyed sleeper, providing theoretical basis for developing sex-control techniques.
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Affiliation(s)
- Mengdan Dong
- School of Marine Sciences, Sun Yat-sen University, Zhuhai 519082, China; Guangdong Provincial Key Laboratory of Marine Resources and Coastal Engineering, Guangzhou 510275, China
| | - Mingyue Tang
- School of Marine Sciences, Sun Yat-sen University, Zhuhai 519082, China; Guangdong Provincial Key Laboratory of Marine Resources and Coastal Engineering, Guangzhou 510275, China
| | - Wenjing Li
- School of Marine Sciences, Sun Yat-sen University, Zhuhai 519082, China; Guangdong Provincial Key Laboratory of Marine Resources and Coastal Engineering, Guangzhou 510275, China
| | - Shizhu Li
- School of Marine Sciences, Sun Yat-sen University, Zhuhai 519082, China; Guangdong Provincial Key Laboratory of Marine Resources and Coastal Engineering, Guangzhou 510275, China
| | - Meisheng Yi
- School of Marine Sciences, Sun Yat-sen University, Zhuhai 519082, China; Guangdong Provincial Key Laboratory of Marine Resources and Coastal Engineering, Guangzhou 510275, China
| | - Wei Liu
- School of Marine Sciences, Sun Yat-sen University, Zhuhai 519082, China; Guangdong Provincial Key Laboratory of Marine Resources and Coastal Engineering, Guangzhou 510275, China.
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6
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Torices S, Daire L, Simon S, Naranjo O, Mendoza L, Teglas T, Fattakhov N, Adesse D, Toborek M. Occludin: a gatekeeper of brain Infection by HIV-1. Fluids Barriers CNS 2023; 20:73. [PMID: 37840143 PMCID: PMC10577960 DOI: 10.1186/s12987-023-00476-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2023] [Accepted: 10/09/2023] [Indexed: 10/17/2023] Open
Abstract
Compromised structure and function of the blood-brain barrier (BBB) is one of the pathological hallmarks of brain infection by HIV-1. BBB damage during HIV-1 infection has been associated with modified expression of tight junction (TJ) proteins, including occludin. Recent evidence indicated occludin as a redox-sensitive, multifunctional protein that can act as both an NADH oxidase and influence cellular metabolism through AMPK kinase. One of the newly identified functions of occludin is its involvement in regulating HIV-1 infection. Studies suggest that occludin expression levels and the rate of HIV-1 infection share a reverse, bidirectional relationship; however, the mechanisms of this relationship are unclear. In this review, we describe the pathways involved in the regulation of HIV-1 infection by occludin. We propose that occludin may serve as a potential therapeutic target to control HIV-1 infection and to improve the lives of people living with HIV-1.
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Affiliation(s)
- Silvia Torices
- Department of Biochemistry and Molecular Biology, University of Miami School of Medicine, 528E Gautier Bldg. 1011 NW 15th Street Miami, Miami, FL, 11336, USA
| | - Leah Daire
- Department of Biochemistry and Molecular Biology, University of Miami School of Medicine, 528E Gautier Bldg. 1011 NW 15th Street Miami, Miami, FL, 11336, USA
| | - Sierra Simon
- Department of Biochemistry and Molecular Biology, University of Miami School of Medicine, 528E Gautier Bldg. 1011 NW 15th Street Miami, Miami, FL, 11336, USA
| | - Oandy Naranjo
- Department of Biochemistry and Molecular Biology, University of Miami School of Medicine, 528E Gautier Bldg. 1011 NW 15th Street Miami, Miami, FL, 11336, USA
| | - Luisa Mendoza
- Department of Biochemistry and Molecular Biology, University of Miami School of Medicine, 528E Gautier Bldg. 1011 NW 15th Street Miami, Miami, FL, 11336, USA
| | - Timea Teglas
- Department of Biochemistry and Molecular Biology, University of Miami School of Medicine, 528E Gautier Bldg. 1011 NW 15th Street Miami, Miami, FL, 11336, USA
| | - Nikolai Fattakhov
- Department of Biochemistry and Molecular Biology, University of Miami School of Medicine, 528E Gautier Bldg. 1011 NW 15th Street Miami, Miami, FL, 11336, USA
| | - Daniel Adesse
- Department of Biochemistry and Molecular Biology, University of Miami School of Medicine, 528E Gautier Bldg. 1011 NW 15th Street Miami, Miami, FL, 11336, USA
- Laboratório de Biologia Estrutural, Instituto Oswaldo Cruz, Fiocruz, Rio de Janeiro, Brazil
| | - Michal Toborek
- Department of Biochemistry and Molecular Biology, University of Miami School of Medicine, 528E Gautier Bldg. 1011 NW 15th Street Miami, Miami, FL, 11336, USA.
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7
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Wei W, Li W, Yang L, Weeramantry S, Ma L, Fu P, Zhao Y. Tight junctions and acute kidney injury. J Cell Physiol 2023; 238:727-741. [PMID: 36815285 DOI: 10.1002/jcp.30976] [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: 09/01/2022] [Revised: 01/27/2023] [Accepted: 02/04/2023] [Indexed: 02/24/2023]
Abstract
Acute kidney injury (AKI) is characterized by a rapid reduction in kidney function caused by various etiologies. Tubular epithelial cell dysregulation plays a pivotal role in the pathogenesis of AKI. Tight junction (TJ) is the major molecular structure that connects adjacent epithelial cells and is critical in maintaining barrier function and determining the permeability of epithelia. TJ proteins are dysregulated in various types of AKI, and some reno-protective drugs can reverse TJ changes caused by insult. An in-depth understanding of TJ regulation and its causality with AKI will provide more insight to the disease pathogenesis and will shed light on the potential role of TJs to serve as novel therapeutic targets in AKI.
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Affiliation(s)
- Wei Wei
- Division of Nephrology and Kidney Research Institute, West China Hospital, Sichuan University, Chengdu, Sichuan, China
| | - Weiying Li
- Department of Internal Medicine, Florida Hospital/AdventHealth, Orlando, Florida, USA
| | - Letian Yang
- Division of Nephrology and Kidney Research Institute, West China Hospital, Sichuan University, Chengdu, Sichuan, China
| | - Savidya Weeramantry
- Department of Internal Medicine, West China School of Medicine, Sichuan University, Chengdu, Sichuan, China
| | - Liang Ma
- Division of Nephrology and Kidney Research Institute, West China Hospital, Sichuan University, Chengdu, Sichuan, China
| | - Ping Fu
- Division of Nephrology and Kidney Research Institute, West China Hospital, Sichuan University, Chengdu, Sichuan, China
| | - Yuliang Zhao
- Division of Nephrology and Kidney Research Institute, West China Hospital, Sichuan University, Chengdu, Sichuan, China
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Mills WA, Coburn MA, Eyo UB. The emergence of the calvarial hematopoietic niche in health and disease. Immunol Rev 2022; 311:26-38. [PMID: 35880587 PMCID: PMC9489662 DOI: 10.1111/imr.13120] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
The diploë region of skull has recently been discovered to act as a myeloid cell reservoir to the underlying meninges. The presence of ossified vascular channels traversing the inner skull of cortex provides a passageway for the cells to traffic from the niche, and CNS-derived antigens traveling through cerebrospinal fluid in a perivascular manner reaches the niche to signal myeloid cell egress. This review will highlight the recent findings establishing this burgeoning field along with the known role this niche plays in CNS aging and disease. It will further highlight the anatomical routes and physiological properties of the vascular structures these cells use for trafficking, spanning from skull to brain parenchyma.
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Affiliation(s)
- William A. Mills
- Brain, Immunology, and Glia CenterUniversity of VirginiaCharlottesvilleVirginiaUSA,Department of NeuroscienceUniversity of VirginiaCharlottesvilleVirginiaUSA,Robert M. Berne Cardiovascular Research CenterUniversity of VirginiaCharlottesvilleVirginiaUSA
| | - Morgan A Coburn
- Brain, Immunology, and Glia CenterUniversity of VirginiaCharlottesvilleVirginiaUSA,Department of NeuroscienceUniversity of VirginiaCharlottesvilleVirginiaUSA,Robert M. Berne Cardiovascular Research CenterUniversity of VirginiaCharlottesvilleVirginiaUSA
| | - Ukpong B. Eyo
- Brain, Immunology, and Glia CenterUniversity of VirginiaCharlottesvilleVirginiaUSA,Department of NeuroscienceUniversity of VirginiaCharlottesvilleVirginiaUSA,Robert M. Berne Cardiovascular Research CenterUniversity of VirginiaCharlottesvilleVirginiaUSA
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9
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Solár P, Zamani A, Lakatosová K, Joukal M. The blood-brain barrier and the neurovascular unit in subarachnoid hemorrhage: molecular events and potential treatments. Fluids Barriers CNS 2022; 19:29. [PMID: 35410231 PMCID: PMC8996682 DOI: 10.1186/s12987-022-00312-4] [Citation(s) in RCA: 41] [Impact Index Per Article: 20.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Accepted: 01/24/2022] [Indexed: 12/12/2022] Open
Abstract
The response of the blood-brain barrier (BBB) following a stroke, including subarachnoid hemorrhage (SAH), has been studied extensively. The main components of this reaction are endothelial cells, pericytes, and astrocytes that affect microglia, neurons, and vascular smooth muscle cells. SAH induces alterations in individual BBB cells, leading to brain homeostasis disruption. Recent experiments have uncovered many pathophysiological cascades affecting the BBB following SAH. Targeting some of these pathways is important for restoring brain function following SAH. BBB injury occurs immediately after SAH and has long-lasting consequences, but most changes in the pathophysiological cascades occur in the first few days following SAH. These changes determine the development of early brain injury as well as delayed cerebral ischemia. SAH-induced neuroprotection also plays an important role and weakens the negative impact of SAH. Supporting some of these beneficial cascades while attenuating the major pathophysiological pathways might be decisive in inhibiting the negative impact of bleeding in the subarachnoid space. In this review, we attempt a comprehensive overview of the current knowledge on the molecular and cellular changes in the BBB following SAH and their possible modulation by various drugs and substances.
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Affiliation(s)
- Peter Solár
- Department of Anatomy, Cellular and Molecular Neurobiology Research Group, Faculty of Medicine, Masaryk University, 625 00, Brno, Czech Republic
- Department of Neurosurgery, Faculty of Medicine, Masaryk University and St. Anne's University Hospital Brno, Pekařská 53, 656 91, Brno, Czech Republic
| | - Alemeh Zamani
- Department of Anatomy, Cellular and Molecular Neurobiology Research Group, Faculty of Medicine, Masaryk University, 625 00, Brno, Czech Republic
| | - Klaudia Lakatosová
- Department of Anatomy, Cellular and Molecular Neurobiology Research Group, Faculty of Medicine, Masaryk University, 625 00, Brno, Czech Republic
| | - Marek Joukal
- Department of Anatomy, Cellular and Molecular Neurobiology Research Group, Faculty of Medicine, Masaryk University, 625 00, Brno, Czech Republic.
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10
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Potjewyd G, Kellett K, Hooper N. 3D hydrogel models of the neurovascular unit to investigate blood-brain barrier dysfunction. Neuronal Signal 2021; 5:NS20210027. [PMID: 34804595 PMCID: PMC8579151 DOI: 10.1042/ns20210027] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Revised: 10/20/2021] [Accepted: 10/22/2021] [Indexed: 12/16/2022] Open
Abstract
The neurovascular unit (NVU), consisting of neurons, glial cells, vascular cells (endothelial cells, pericytes and vascular smooth muscle cells (VSMCs)) together with the surrounding extracellular matrix (ECM), is an important interface between the peripheral blood and the brain parenchyma. Disruption of the NVU impacts on blood-brain barrier (BBB) regulation and underlies the development and pathology of multiple neurological disorders, including stroke and Alzheimer's disease (AD). The ability to differentiate induced pluripotent stem cells (iPSCs) into the different cell types of the NVU and incorporate them into physical models provides a reverse engineering approach to generate human NVU models to study BBB function. To recapitulate the in vivo situation such NVU models must also incorporate the ECM to provide a 3D environment with appropriate mechanical and biochemical cues for the cells of the NVU. In this review, we provide an overview of the cells of the NVU and the surrounding ECM, before discussing the characteristics (stiffness, functionality and porosity) required of hydrogels to mimic the ECM when incorporated into in vitro NVU models. We summarise the approaches available to measure BBB functionality and present the techniques in use to develop robust and translatable models of the NVU, including transwell models, hydrogel models, 3D-bioprinting, microfluidic models and organoids. The incorporation of iPSCs either without or with disease-specific genetic mutations into these NVU models provides a platform in which to study normal and disease mechanisms, test BBB permeability to drugs, screen for new therapeutic targets and drugs or to design cell-based therapies.
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Affiliation(s)
- Geoffrey Potjewyd
- Division of Neuroscience and Experimental Psychology, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester M13 9PT, U.K
| | - Katherine A.B. Kellett
- Division of Neuroscience and Experimental Psychology, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester M13 9PT, U.K
| | - Nigel M. Hooper
- Division of Neuroscience and Experimental Psychology, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester M13 9PT, U.K
- Geoffrey Jefferson Brain Research Centre, Manchester Academic Health Science Centre, Northern Care Alliance and University of Manchester, Manchester, U.K
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Kim J, Tamura A, Tsukita S, Park S. Uniaxial stretching device for studying maturity-dependent morphological response of epithelial cell monolayers to tensile strain. J IND ENG CHEM 2021. [DOI: 10.1016/j.jiec.2021.04.036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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12
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Duarte Lobo D, Nobre RJ, Oliveira Miranda C, Pereira D, Castelhano J, Sereno J, Koeppen A, Castelo-Branco M, Pereira de Almeida L. The blood-brain barrier is disrupted in Machado-Joseph disease/spinocerebellar ataxia type 3: evidence from transgenic mice and human post-mortem samples. Acta Neuropathol Commun 2020; 8:152. [PMID: 32867861 PMCID: PMC7457506 DOI: 10.1186/s40478-020-00955-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2020] [Accepted: 05/25/2020] [Indexed: 12/20/2022] Open
Abstract
Blood-brain barrier (BBB) disruption is a common feature in neurodegenerative diseases. However, BBB integrity has not been assessed in spinocerebellar ataxias (SCAs) such as Machado-Joseph disease/SCA type 3 (MJD/SCA3), a genetic disorder, triggered by polyglutamine-expanded ataxin-3. To investigate that, BBB integrity was evaluated in a transgenic mouse model of MJD and in human post-mortem brain tissues. Firstly, we investigated the BBB permeability in MJD mice by: i) assessing the extravasation of the Evans blue (EB) dye and blood-borne proteins (e.g fibrinogen) in the cerebellum by immunofluorescence, and ii) in vivo Dynamic Contrast Enhanced-Magnetic Resonance Imaging (DCE-MRI). The presence of ataxin-3 aggregates in brain blood vessels and the levels of tight junction (TJ)-associated proteins were also explored by immunofluorescence and western blotting. Human brain samples were used to confirm BBB permeability by evaluating fibrinogen extravasation, co-localization of ataxin-3 aggregates with brain blood vessels and neuroinflammation. In the cerebellum of the mouse model of MJD, there was a 5-fold increase in EB accumulation when compared to age-matched controls. Moreover, vascular permeability displayed a 13-fold increase demonstrated by DCE-MRI. These results were validated by the 2-fold increase in fibrinogen extravasation in transgenic animals comparing to controls. Interestingly, mutant ataxin-3 aggregates were detected in cerebellar blood vessels of transgenic mice, accompanied by alterations of TJ-associated proteins in cerebellar endothelial cells, namely a 29% decrease in claudin-5 oligomers and a 10-fold increase in an occludin cleavage fragment. These results were validated in post-mortem brain samples from MJD patients as we detected fibrinogen extravasation across BBB, the presence of ataxin-3 aggregates in blood vessels and associated microgliosis. Altogether, our results prove BBB impairment in MJD/SCA3. These findings contribute for a better understanding of the disease mechanisms and opens the opportunity to treat MJD with medicinal products that in normal conditions would not cross the BBB.
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Bierbaumer L, Schwarze UY, Gruber R, Neuhaus W. Cell culture models of oral mucosal barriers: A review with a focus on applications, culture conditions and barrier properties. Tissue Barriers 2018; 6:1479568. [PMID: 30252599 PMCID: PMC6389128 DOI: 10.1080/21688370.2018.1479568] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Understanding the function of oral mucosal epithelial barriers is essential for a plethora of research fields such as tumor biology, inflammation and infection diseases, microbiomics, pharmacology, drug delivery, dental and biomarker research. The barrier properties are comprised by a physical, a transport and a metabolic barrier, and all these barrier components play pivotal roles in the communication between saliva and blood. The sum of all epithelia of the oral cavity and salivary glands is defined as the blood-saliva barrier. The functionality of the barrier is regulated by its microenvironment and often altered during diseases. A huge array of cell culture models have been developed to mimic specific parts of the blood-saliva barrier, but no ultimate standard in vitro models have been established. This review provides a comprehensive overview about developed in vitro models of oral mucosal barriers, their applications, various cultivation protocols and corresponding barrier properties.
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Affiliation(s)
- Lisa Bierbaumer
- a Competence Unit Molecular Diagnostics, Center Health and Bioresources, Austrian Institute of Technology (AIT) GmbH , Vienna , Austria
| | - Uwe Yacine Schwarze
- b Department of Oral Biology , School of Dentistry, Medical University of Vienna , Vienna , Austria.,c Austrian Cluster for Tissue Regeneration , Vienna , Austria
| | - Reinhard Gruber
- b Department of Oral Biology , School of Dentistry, Medical University of Vienna , Vienna , Austria.,c Austrian Cluster for Tissue Regeneration , Vienna , Austria.,d Department of Periodontology , School of Dental Medicine, University of Bern , Bern , Switzerland
| | - Winfried Neuhaus
- a Competence Unit Molecular Diagnostics, Center Health and Bioresources, Austrian Institute of Technology (AIT) GmbH , Vienna , Austria
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Zhang L, Feng T, Spicer LJ. The role of tight junction proteins in ovarian follicular development and ovarian cancer. Reproduction 2018; 155:R183-R198. [PMID: 29374086 DOI: 10.1530/rep-17-0503] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2017] [Accepted: 01/26/2018] [Indexed: 01/01/2023]
Abstract
Tight junctions (TJ) are protein structures that control the transport of water, ions and macromolecules across cell layers. Functions of the transmembrane TJ protein, occluding (OCLN) and the cytoplasmic TJ proteins, tight junction protein 1 (TJP1; also known as zona occludens protein-1), cingulin (CGN) and claudins (CLDN) are reviewed, and current evidence of their role in the ovarian function is reviewed. Abundance of OCLN, CLDNs and TJP1 mRNA changed during follicular growth. In vitro treatment with various growth factors known to affect ovarian folliculogenesis indicated that CGN, OCLN and TJP1 are hormonally regulated. The summarized studies indicate that expression of TJ proteins (i.e., OCLN, CLDN, TJP1 and CGN) changes with follicle size in a variety of vertebrate species but whether these changes in TJ proteins are increased or decreased depends on species and cell type. Evidence indicates that autocrine, paracrine and endocrine regulators, such as fibroblast growth factor-9, epidermal growth factor, androgens, tumor necrosis factor-α and glucocorticoids may modulate these TJ proteins. Additional evidence presented indicates that TJ proteins may be involved in ovarian cancer development in addition to normal follicular and luteal development. A model is proposed suggesting that hormonal downregulation of TJ proteins during ovarian follicular development could reduce barrier function (i.e., selective permeability of molecules between theca and granulosa cells) and allow for an increase in the volume of follicular fluid as well as allow additional serum factors into the follicle that may directly impact granulosa cell functions.
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Affiliation(s)
- Lingna Zhang
- Department of Animal ScienceOklahoma State University, Stillwater, Oklahoma, USA
| | - Tao Feng
- Institute of Animal Husbandry and Veterinary MedicineBeijing Academy of Agriculture and Forestry Sciences, Beijing, China
| | - Leon J Spicer
- Department of Animal ScienceOklahoma State University, Stillwater, Oklahoma, USA
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Na W, Shin JY, Lee JY, Jeong S, Kim WS, Yune TY, Ju BG. Dexamethasone suppresses JMJD3 gene activation via a putative negative glucocorticoid response element and maintains integrity of tight junctions in brain microvascular endothelial cells. J Cereb Blood Flow Metab 2017; 37:3695-3708. [PMID: 28338398 PMCID: PMC5718327 DOI: 10.1177/0271678x17701156] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The blood-brain barrier (BBB) exhibits a highly selective permeability to support the homeostasis of the central nervous system (CNS). The tight junctions in the BBB microvascular endothelial cells seal the paracellular space to prevent diffusion. Thus, disruption of tight junctions results in harmful effects in CNS diseases and injuries. It has recently been demonstrated that glucocorticoids have beneficial effects on maintaining tight junctions in both in vitro cell and in vivo animal models. In the present study, we found that dexamethasone suppresses the expression of JMJD3, a histone H3K27 demethylase, via the recruitment of glucocorticoid receptor α (GRα) and nuclear receptor co-repressor (N-CoR) to the negative glucocorticoid response element (nGRE) in the upstream region of JMJD3 gene in brain microvascular endothelial cells subjected to TNFα treatment. The decreased JMJD3 gene expression resulted in the suppression of MMP-2, MMP-3, and MMP-9 gene activation. Dexamethasone also activated the expression of the claudin 5 and occludin genes. Collectively, dexamethasone attenuated the disruption of the tight junctions in the brain microvascular endothelial cells subjected to TNFα treatment. Therefore, glucocorticoids may help to preserve the integrity of the tight junctions in the BBB via transcriptional and post-translational regulation following CNS diseases and injuries.
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Affiliation(s)
- Wonho Na
- 1 Department of Life Science, Sogang University, Seoul, Korea
| | - Jee Y Shin
- 1 Department of Life Science, Sogang University, Seoul, Korea
| | - Jee Y Lee
- 2 Age-Related and Brain Diseases Research Center, Kyung Hee University, Seoul, Korea
| | - Sangyun Jeong
- 3 Department of Molecular Biology, Chonbuk National University, Jeonju, Korea
| | - Won-Sun Kim
- 1 Department of Life Science, Sogang University, Seoul, Korea
| | - Tae Y Yune
- 2 Age-Related and Brain Diseases Research Center, Kyung Hee University, Seoul, Korea.,4 Department of Biochemistry and Molecular Biology, School of Medicine, Kyung Hee University, Seoul, Korea
| | - Bong-Gun Ju
- 1 Department of Life Science, Sogang University, Seoul, Korea
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Zhang L, Schütz LF, Robinson CL, Totty ML, Spicer LJ. Evidence that gene expression of ovarian follicular tight junction proteins is regulated in vivo and in vitro in cattle. J Anim Sci 2017; 95:1313-1324. [PMID: 28380519 DOI: 10.2527/jas.2016.0892] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Tight junctions (TJ) are common paracellular sealing structures that control the transport of water, ions, and macromolecules across cell layers. Because the role of TJ in bovine follicular development is unknown, we investigated the developmental and hormonal regulation of the transmembrane TJ protein, occludin (OCLN), and the cytoplasmic TJ proteins, TJ protein 1 (TJP1) and cingulin (CGN) in bovine granulosa cells (GC) and theca cells (TC). For this purpose, bovine GC and TC were isolated from large (>8 mm) and/or small (1 to 5 mm) follicles and either extracted for real-time PCR (qPCR) or cultured in vitro. The abundances of both and mRNA were greater ( < 0.05) in TC than GC, whereas the mRNA abundance was greater ( < 0.05) in GC than TC. The abundance of mRNA in both GC and TC was greater ( < 0.05) in small follicles compared with large follicles, whereas the GC of large follicles had less ( < 0.05) mRNA abundance than the GC of small follicles. The abundance of mRNA in GC or TC did not differ ( > 0.10) among follicle sizes. In vitro treatment with various growth factors known to affect ovarian folliculogenesis indicated that , , and were hormonally regulated. Fibroblast growth factor 9 (FGF9) decreased ( < 0.05) the and mRNA abundances. Tumor necrosis factor α (TNFα) and vascular endothelial growth factor A (VEGFA) increased ( < 0.05) the mRNA abundance but decreased ( < 0.05) the mRNA abundance. Dexamethasone (DEX) increased ( < 0.05) and mRNA abundances. Epidermal growth factor (EGF) decreased ( < 0.05) and dihydrotestosterone (DHT) increased ( < 0.05) the abundances of , , and mRNA. We propose that the downregulation of OCLN and other TJ proteins during follicular development could reduce barrier function, thereby participating in increasing follicle size by allowing for an increase in the volume of follicular fluid as well as by allowing additional serum factors into the follicular fluid that potentially may directly impact GC functions. The results of the current study indicate the following in cattle: 1) gene expression of TJ proteins (i.e., , , and ) differs between GC and TC and changes with follicle size, and 2) autocrine, paracrine, and endocrine regulators, such as FGF9, EGF, DHT, TNFα, and glucocorticoids, modulate , , and mRNA abundance in TC in vitro.
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Miyoshi Y, Tanabe S, Suzuki T. Cellular zinc is required for intestinal epithelial barrier maintenance via the regulation of claudin-3 and occludin expression. Am J Physiol Gastrointest Liver Physiol 2016; 311:G105-16. [PMID: 27151944 DOI: 10.1152/ajpgi.00405.2015] [Citation(s) in RCA: 69] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/16/2015] [Accepted: 05/02/2016] [Indexed: 01/31/2023]
Abstract
Intracellular zinc is required for a variety of cell functions, but its precise roles in the maintenance of the intestinal tight junction (TJ) barrier remain unclear. The present study investigated the essential roles of intracellular zinc in the preservation of intestinal TJ integrity and the underlying molecular mechanisms. Depletion of intracellular zinc in both intestinal Caco-2 cells and mouse colons through the application of a cell-permeable zinc chelator N,N,N',N'-tetrakis(2-pyridylmethyl)ethylenediamine (TPEN) induced a disruption of the TJ barrier, as indicated by increased FITC-labeled dextran flux and decreased transepithelial electrical resistance. The TPEN-induced TJ disruption is associated with downregulation of two TJ proteins, occludin and claudin-3. Biotinylation of cell surface proteins revealed that the zinc depletion induced the proteolysis of occludin but not claudin-3. Occludin proteolysis was sensitive to the inhibition of calpain activity, and increased calpain activity was observed in the zinc-depleted cells. Although quantitative PCR analysis and promoter reporter assay have demonstrated that the zinc depletion-induced claudin-3 downregulation occurred at transcriptional levels, a site-directed mutation in the egr1 binding site in the claudin-3 promoter sequence induced loss of both the basal promoter activity and the TPEN-induced decreases. Reduced egr1 expression by a specific siRNA also inhibited claudin-3 expression and transepithelial electrical resistance maintenance in cells. This study shows that intracellular zinc has an essential role in the maintenance of the intestinal epithelial TJ barrier through regulation of occludin proteolysis and claudin-3 transcription.
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Affiliation(s)
- Yuka Miyoshi
- Department of Biofunctional Science and Technology, Graduate School of Biosphere Science, Hiroshima University, Higashi-Hiroshima, Japan
| | - Soichi Tanabe
- Department of Biofunctional Science and Technology, Graduate School of Biosphere Science, Hiroshima University, Higashi-Hiroshima, Japan
| | - Takuya Suzuki
- Department of Biofunctional Science and Technology, Graduate School of Biosphere Science, Hiroshima University, Higashi-Hiroshima, Japan
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18
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Baker OJ. Current trends in salivary gland tight junctions. Tissue Barriers 2016; 4:e1162348. [PMID: 27583188 DOI: 10.1080/21688370.2016.1162348] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2016] [Revised: 02/28/2016] [Accepted: 03/01/2016] [Indexed: 12/21/2022] Open
Abstract
Tight junctions form a continuous intercellular barrier between epithelial cells that is required to separate tissue spaces and regulate selective movement of solutes across the epithelium. They are composed of strands containing integral membrane proteins (e.g., claudins, occludin and tricellulin, junctional adhesion molecules and the coxsackie adenovirus receptor). These proteins are anchored to the cytoskeleton via scaffolding proteins such as ZO-1 and ZO-2. In salivary glands, tight junctions are involved in polarized saliva secretion and barrier maintenance between the extracellular environment and the glandular lumen. This review seeks to provide an overview of what is currently known, as well as the major questions and future research directions, regarding tight junction expression, organization and function within salivary glands.
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Affiliation(s)
- Olga J Baker
- School of Dentistry, University of Utah , Salt Lake City, UT, USA
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Reinforced Epithelial Barrier Integrity via Matriptase Induction with Sphingosine-1-Phosphate Did Not Result in Disturbances in Physiological Redox Status. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2015; 2016:9674272. [PMID: 26823955 PMCID: PMC4707357 DOI: 10.1155/2016/9674272] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/17/2015] [Revised: 10/10/2015] [Accepted: 10/19/2015] [Indexed: 12/18/2022]
Abstract
Objectives. The relationship among matriptase function, cellular redox status, and maintenance of intestinal barrier integrity has not been established yet. The aim of this study is to reveal if the crosstalk between matriptase activators and intestinal epithelial monolayers can lead to perturbations in physiological redox regulation in vitro. Methods. The effects of suramin and sphingosine-1-phosphate (S1P) were tested on viability of intestinal porcine epithelial IPEC-J2 cells using MTS assay. Measurements of transepithelial electrical resistance (TER) were performed to determine changes in barrier integrity of cell monolayers. Amplex Red assay was used to monitor extracellular hydrogen peroxide production. Occludin distribution pattern was detected prior to and after matriptase activation using immunofluorescent staining technique. Results. TER reduction was observed in suramin-treated IPEC-J2 cell monolayers, which could be attributed to cell cytotoxic properties of 48 hr 50 μM suramin administration. In contrast, S1P treatment increased TER significantly and elevated occludin accumulation in tight junctions. It was also found that extracellular hydrogen peroxide levels were maintained in IPEC-J2 cells exposed to matriptase activators. Discussion. S1P administration not accompanied by redox imbalance might be one of the key strategies in the improvement of barrier function and consequently in the therapy of intestinal inflammations.
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Broux B, Gowing E, Prat A. Glial regulation of the blood-brain barrier in health and disease. Semin Immunopathol 2015; 37:577-90. [PMID: 26245144 DOI: 10.1007/s00281-015-0516-2] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2015] [Accepted: 07/15/2015] [Indexed: 12/14/2022]
Abstract
The brain is the organ with the highest metabolic demand in the body. Therefore, it needs specialized vasculature to provide it with the necessary oxygen and nutrients, while protecting it against pathogens and toxins. The blood-brain barrier (BBB) is very tightly regulated by specialized endothelial cells, two basement membranes, and astrocytic endfeet. The proximity of astrocytes to the vessel makes them perfect candidates to influence the function of the BBB. Moreover, other glial cells are also known to contribute to either BBB quiescence or breakdown. In this review, we summarize the knowledge on glial regulation of the BBB during development, in homeostatic conditions in the adult, and during neuroinflammatory responses.
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Affiliation(s)
- Bieke Broux
- Neuroimmunology Unit, Centre de Recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), 900 Rue Saint Denis Street, Room R9.912, Montréal, Québec, Canada, H2X 0A9
- Department of Neuroscience, Faculté de Médecine, Université de Montréal, Montréal, Canada
- Hasselt University, Biomedical Research Institute and transnationale Universiteit Limburg, School of Life Sciences, Agoralaan, Building C, 3590, Diepenbeek, Belgium
| | - Elizabeth Gowing
- Neuroimmunology Unit, Centre de Recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), 900 Rue Saint Denis Street, Room R9.912, Montréal, Québec, Canada, H2X 0A9
- Department of Neuroscience, Faculté de Médecine, Université de Montréal, Montréal, Canada
| | - Alexandre Prat
- Neuroimmunology Unit, Centre de Recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), 900 Rue Saint Denis Street, Room R9.912, Montréal, Québec, Canada, H2X 0A9.
- Department of Neuroscience, Faculté de Médecine, Université de Montréal, Montréal, Canada.
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Weight CM, Jones EJ, Horn N, Wellner N, Carding SR. Elucidating pathways of Toxoplasma gondii invasion in the gastrointestinal tract: involvement of the tight junction protein occludin. Microbes Infect 2015; 17:698-709. [PMID: 26183539 DOI: 10.1016/j.micinf.2015.07.001] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2015] [Revised: 06/17/2015] [Accepted: 07/02/2015] [Indexed: 01/28/2023]
Abstract
Toxoplasma gondii is an obligate intracellular parasite infecting one third of the world's population. The small intestine is the parasite's primary route of infection, although the pathway of epithelium transmigration remains unclear. Using an in vitro invasion assay and live imaging we showed that T. gondii (RH) tachyzoites infect and transmigrate between adjacent intestinal epithelial cells in polarized monolayers without altering barrier integrity, despite eliciting the production of specific inflammatory mediators and chemokines. During invasion, T. gondii co-localized with occludin. Reducing the levels of endogenous cellular occludin with specific small interfering RNAs significantly reduced the ability of T. gondii to penetrate between and infect epithelial cells. Furthermore, an in vitro invasion and binding assays using recombinant occludin fragments established the capacity of the parasite to bind occludin and in particular to the extracellular loops of the protein. These findings provide evidence for occludin playing a role in the invasion of T. gondii in small intestinal epithelial cells.
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Affiliation(s)
- Caroline M Weight
- Gut Health and Food Safety Institute Strategic Programme, Norwich Research Park, Norwich, NR4 7UA, UK; Norwich Medical School, University of East Anglia, Norwich Research Park, Norwich, NR4 7UA, UK
| | - Emily J Jones
- Gut Health and Food Safety Institute Strategic Programme, Norwich Research Park, Norwich, NR4 7UA, UK; Norwich Medical School, University of East Anglia, Norwich Research Park, Norwich, NR4 7UA, UK
| | - Nikki Horn
- Gut Health and Food Safety Institute Strategic Programme, Norwich Research Park, Norwich, NR4 7UA, UK
| | - Nikolaus Wellner
- Analytical Sciences Unit, Institute of Food Research, Norwich Research Park, Norwich, NR4 7UA, UK
| | - Simon R Carding
- Gut Health and Food Safety Institute Strategic Programme, Norwich Research Park, Norwich, NR4 7UA, UK; Norwich Medical School, University of East Anglia, Norwich Research Park, Norwich, NR4 7UA, UK.
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Posada-Duque RA, Barreto GE, Cardona-Gomez GP. Protection after stroke: cellular effectors of neurovascular unit integrity. Front Cell Neurosci 2014; 8:231. [PMID: 25177270 PMCID: PMC4132372 DOI: 10.3389/fncel.2014.00231] [Citation(s) in RCA: 87] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2014] [Accepted: 07/24/2014] [Indexed: 12/16/2022] Open
Abstract
Neurological disorders are prevalent worldwide. Cerebrovascular diseases (CVDs), which account for 55% of all neurological diseases, are the leading cause of permanent disability, cognitive and motor disorders and dementia. Stroke affects the function and structure of blood-brain barrier, the loss of cerebral blood flow regulation, oxidative stress, inflammation and the loss of neural connections. Currently, no gold standard treatments are available outside the acute therapeutic window to improve outcome in stroke patients. Some promising candidate targets have been identified for the improvement of long-term recovery after stroke, such as Rho GTPases, cell adhesion proteins, kinases, and phosphatases. Previous studies by our lab indicated that Rho GTPases (Rac and RhoA) are involved in both tissue damage and survival, as these proteins are essential for the morphology and movement of neurons, astrocytes and endothelial cells, thus playing a critical role in the balance between cell survival and death. Treatment with a pharmacological inhibitor of RhoA/ROCK blocks the activation of the neurodegeneration cascade. In addition, Rac and synaptic adhesion proteins (p120 catenin and N-catenin) play critical roles in protection against cerebral infarction and in recovery by supporting the neurovascular unit and cytoskeletal remodeling activity to maintain the integrity of the brain parenchyma. Interestingly, neuroprotective agents, such as atorvastatin, and CDK5 silencing after cerebral ischemia and in a glutamate-induced excitotoxicity model may act on the same cellular effectors to recover neurovascular unit integrity. Therefore, future efforts must focus on individually targeting the structural and functional roles of each effector of neurovascular unit and the interactions in neural and non-neural cells in the post-ischemic brain and address how to promote the recovery or prevent the loss of homeostasis in the short, medium and long term.
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Affiliation(s)
- Rafael Andres Posada-Duque
- Cellular and Molecular Neurobiology Area, Group of Neuroscience of Antioquia, Faculty of Medicine, Sede de Investigación Universitaria (SIU), University of Antioquia UdeA Medellín, Colombia
| | - George E Barreto
- Departamento de Nutrición y Bioquímica, Facultad de Ciencias, Pontificia Universidad Javeriana Bogotá D.C., Colombia
| | - Gloria Patricia Cardona-Gomez
- Cellular and Molecular Neurobiology Area, Group of Neuroscience of Antioquia, Faculty of Medicine, Sede de Investigación Universitaria (SIU), University of Antioquia UdeA Medellín, Colombia
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Chen D, Li L, Yan J, Yang X, You Y, Zhou Y, Ling X. The loss of αSNAP downregulates the expression of occludin in the intestinal epithelial cell of acute pancreatitis model. Pancreatology 2014; 14:347-55. [PMID: 25278303 DOI: 10.1016/j.pan.2014.06.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/16/2013] [Revised: 06/11/2014] [Accepted: 06/23/2014] [Indexed: 12/11/2022]
Abstract
BACKGROUND AND OBJECTIVE Intestinal barrier damage is an important event during the occurrence and progression of severe acute pancreatitis. The expression of occludin, one of the main components of the intestinal barrier proteins, is regulated by various factors related to intestinal barrier formation and the remodeling process. The αSNAP, as a novel membrane protein, is ubiquitously expressed in intestinal epithelial cells. This study aimed to investigate the role of αSNAP in acute pancreatitis and the relationship between occludin and αSNAP. METHODS Mild and severe acute pancreatitis models were established by retrograde injections of 0.5% and 3.8% sodium taurocholate solutions, respectively, into rat pancreaticobiliary ducts. The animals were killed at 1, 2, and 3 days after the injection, and the pathological changes of the pancreas and intestinal mucosa, the changes in intestinal permeability, and the protein expression of occludin and αSNAP were assessed. Cultured epithelial IEC-6 cells were further infected with lentiviral αSNAP shRNA, cell apoptosis was determined with flow cytometry (FCM), and any changes in occludin expression were detected by Western blotting and immunofluorescent staining. RESULTS This pathologic study of a rat acute pancreatitis model indicated pancreatic tissue necrosis and inflammatory cell infiltration; the intestinal villi in the severe acute pancreatitis (SAP) group demonstrated edema, lodging, atrophy, and intestinal epithelial cell necrosis, and shedding. The intestinal permeability in rats with pancreatitis increased significantly. The SAP group showed significantly increased levels of serum TNF-α and endotoxins. The results of immunofluorescent staining and Western blotting revealed that compared with the SO (sham operation) and MAP (mild acute pancreatitis) groups, the SAP group displayed significantly downregulated protein expressions of αSNAP and occludin in the intestinal epithelial cells. After the lentiviral transduction of αSNAP shRNA, apoptosis in IEC-6 cells was drastically increased, whereas the expression of occludin was decreased significantly. CONCLUSION The downregulated expression of αSNAP in intestinal epithelial cells leads to reduced occludin expression and enhanced apoptosis of intestinal epithelial cells. Hence, the permeability of the intestinal barrier may be increased in a severe acute pancreatitis model.
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Affiliation(s)
- Daixing Chen
- Department of Gastroenterology, Xinqiao Hospital, Third Military Medical University, Chongqing 400037, China
| | - Lili Li
- Department of Gastroenterology, Xinqiao Hospital, Third Military Medical University, Chongqing 400037, China
| | - Jing Yan
- Department of Gastroenterology, Xinqiao Hospital, Third Military Medical University, Chongqing 400037, China
| | - Xin Yang
- Department of Gastroenterology, Xinqiao Hospital, Third Military Medical University, Chongqing 400037, China
| | - Yang You
- Department of Gastroenterology, Xinqiao Hospital, Third Military Medical University, Chongqing 400037, China
| | - Yuan Zhou
- Department of Gastroenterology, Xinqiao Hospital, Third Military Medical University, Chongqing 400037, China.
| | - Xianlong Ling
- Department of Gastroenterology, Xinqiao Hospital, Third Military Medical University, Chongqing 400037, China.
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Wen J, Qian S, Yang Q, Deng L, Mo Y, Yu Y. Overexpression of netrin-1 increases the expression of tight junction-associated proteins, claudin-5, occludin, and ZO-1, following traumatic brain injury in rats. Exp Ther Med 2014; 8:881-886. [PMID: 25120618 PMCID: PMC4113541 DOI: 10.3892/etm.2014.1818] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2014] [Accepted: 05/13/2014] [Indexed: 12/18/2022] Open
Abstract
The function of the blood-brain barrier (BBB) depends on the integrity of tight junction (TJ)-associated proteins. Netrin-1 is known to promote angiogenesis and may also regulate the BBB. To understand the association between netrin-1 and the TJ-associated proteins, the expression levels of proteins involved in maintaining the integrity of the BBB, including netrin-1, claudin-5, occludin and zonula occluden (ZO)-1, were investigated in the present study using quantitative polymerase chain reaction, western blot analysis and immunofluorescence. The aim of the present study was to determine the changes in BBB permeability and whether pZsGreen1-N1 mediated overexpression of netrin-1 increased the expression of the TJ-associated proteins following traumatic brain injury (TBI). The results demonstrated that the levels of mRNA transcription and protein expression of the TJ-associated proteins, claudin-5, occludin and ZO-1, were significantly reduced following TBI. Furthermore, the changes in the expression of these three TJ proteins were consistent with the changes in the BBB permeability, indicating that weakening intercellular junctions leads to BBB opening. The present study also demonstrated that netrin-1 significantly increased the downregulation of claudin-5, occludin and ZO-1 expression levels induced by TBI, which provided a basis for further investigation on the role of netrin-1 in the integrity of TJs and proper functioning of the BBB.
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Affiliation(s)
- Jianfeng Wen
- Department of Neurosurgery, Changcheng Sub-Hospital of Nanchang University, Nanchang, Jiangxi 330002, P.R. China ; Department of Neurosurgery, The 94 Hospital of PLA, Nanchang, Jiangxi 330002, P.R. China
| | - Suokai Qian
- Department of Neurosurgery, The 94 Hospital of PLA, Nanchang, Jiangxi 330002, P.R. China
| | - Qifan Yang
- Department of Neurosurgery, The 94 Hospital of PLA, Nanchang, Jiangxi 330002, P.R. China
| | - Lei Deng
- Department of Neurosurgery, The 94 Hospital of PLA, Nanchang, Jiangxi 330002, P.R. China
| | - Ye Mo
- Department of Nursing, The 94 Hospital of PLA, Nanchang, Jiangxi 330002, P.R. China
| | - Yuefei Yu
- Department of Neurosurgery, Changcheng Sub-Hospital of Nanchang University, Nanchang, Jiangxi 330002, P.R. China ; Department of Internal Medicine, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA
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Szaszi K, Amoozadeh Y. New Insights into Functions, Regulation, and Pathological Roles of Tight Junctions in Kidney Tubular Epithelium. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2014; 308:205-71. [DOI: 10.1016/b978-0-12-800097-7.00006-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
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26
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Glucocorticoids and endothelial cell barrier function. Cell Tissue Res 2013; 355:597-605. [PMID: 24352805 PMCID: PMC3972429 DOI: 10.1007/s00441-013-1762-z] [Citation(s) in RCA: 97] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2013] [Accepted: 11/05/2013] [Indexed: 01/14/2023]
Abstract
Glucocorticoids (GCs) are steroid hormones that have inflammatory and immunosuppressive effects on a wide variety of cells. They are used as therapy for inflammatory disease and as a common agent against edema. The blood brain barrier (BBB), comprising microvascular endothelial cells, serves as a permeability screen between the blood and the brain. As such, it maintains homeostasis of the central nervous system (CNS). In many CNS disorders, BBB integrity is compromised. GC treatment has been demonstrated to improve the tightness of the BBB. The responses and effects of GCs are mediated by the ubiquitous GC receptor (GR). Ligand-bound GR recognizes and binds to the GC response element located within the promoter region of target genes. Transactivation of certain target genes leads to improved barrier properties of endothelial cells. In this review, we deal with the role of GCs in endothelial cell barrier function. First, we describe the mechanisms of GC action at the molecular level. Next, we discuss the regulation of the BBB by GCs, with emphasis on genes targeted by GCs such as occludin, claudins and VE-cadherin. Finally, we present currently available GC therapeutic strategies and their limitations.
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Abstract
Increased endothelial permeability and reduction of alveolar liquid clearance capacity are two leading pathogenic mechanisms of pulmonary edema, which is a major complication of acute lung injury, severe pneumonia, and acute respiratory distress syndrome, the pathologies characterized by unacceptably high rates of morbidity and mortality. Besides the success in protective ventilation strategies, no efficient pharmacological approaches exist to treat this devastating condition. Understanding of fundamental mechanisms involved in regulation of endothelial permeability is essential for development of barrier protective therapeutic strategies. Ongoing studies characterized specific barrier protective mechanisms and identified intracellular targets directly involved in regulation of endothelial permeability. Growing evidence suggests that, although each protective agonist triggers a unique pattern of signaling pathways, selected common mechanisms contributing to endothelial barrier protection may be shared by different barrier protective agents. Therefore, understanding of basic barrier protective mechanisms in pulmonary endothelium is essential for selection of optimal treatment of pulmonary edema of different etiology. This article focuses on mechanisms of lung vascular permeability, reviews major intracellular signaling cascades involved in endothelial monolayer barrier preservation and summarizes a current knowledge regarding recently identified compounds which either reduce pulmonary endothelial barrier disruption and hyperpermeability, or reverse preexisting lung vascular barrier compromise induced by pathologic insults.
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Affiliation(s)
- Konstantin G Birukov
- Lung Injury Center, Section of Pulmonary and Critical Care, Department of Medicine, University of Chicago, Chicago, Illinois, USA.
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Effects of soybean agglutinin on mechanical barrier function and tight junction protein expression in intestinal epithelial cells from piglets. Int J Mol Sci 2013; 14:21689-704. [PMID: 24189218 PMCID: PMC3856029 DOI: 10.3390/ijms141121689] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2013] [Revised: 09/24/2013] [Accepted: 10/08/2013] [Indexed: 12/14/2022] Open
Abstract
In this study, we sought to investigate the role of soybean agglutinin (SBA) in mediating membrane permeability and the mechanical barrier function of intestinal epithelial cells. The IPEC-J2 cells were cultured and treated with 0, 0.5, 1.0, 1.5, 2.0, 2.5, or 3.0 mg/mL SBA. Transepithelial electrical resistance (TEER) and alkaline phosphatase (AP) activity were measured to evaluate membrane permeability. The results showed a significant decrease in TEER values (p < 0.05) in a time- and dose-dependent manner, and a pronounced increase in AP activity (p < 0.05). Cell growth and cell morphology were used to evaluate the cell viability. A significant cell growth inhibition (p < 0.05) and alteration of morphology were observed when the concentration of SBA was increased. The results of western blotting showed that the expression levels of occludin and claudin-3 were decreased by 31% and 64% compared to those of the control, respectively (p < 0.05). In addition, immunofluorescence labeling indicated an obvious decrease in staining of these targets and changes in their localizations. In conclusion, SBA increased the membrane permeability, inhibited the cell viability and reduced the levels of tight junction proteins (occludin and claudin-3), leading to a decrease in mechanical barrier function in intestinal epithelial cells.
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Buschmann MM, Shen L, Rajapakse H, Raleigh DR, Wang Y, Wang Y, Lingaraju A, Zha J, Abbott E, McAuley EM, Breskin LA, Wu L, Anderson K, Turner JR, Weber CR. Occludin OCEL-domain interactions are required for maintenance and regulation of the tight junction barrier to macromolecular flux. Mol Biol Cell 2013; 24:3056-68. [PMID: 23924897 PMCID: PMC3784380 DOI: 10.1091/mbc.e12-09-0688] [Citation(s) in RCA: 132] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2012] [Revised: 07/10/2013] [Accepted: 07/30/2013] [Indexed: 12/31/2022] Open
Abstract
In vitro and in vivo studies implicate occludin in the regulation of paracellular macromolecular flux at steady state and in response to tumor necrosis factor (TNF). To define the roles of occludin in these processes, we established intestinal epithelia with stable occludin knockdown. Knockdown monolayers had markedly enhanced tight junction permeability to large molecules that could be modeled by size-selective channels with radii of ~62.5 Å. TNF increased paracellular flux of large molecules in occludin-sufficient, but not occludin-deficient, monolayers. Complementation using full-length or C-terminal coiled-coil occludin/ELL domain (OCEL)-deficient enhanced green fluorescent protein (EGFP)-occludin showed that TNF-induced occludin endocytosis and barrier regulation both required the OCEL domain. Either TNF treatment or OCEL deletion accelerated EGFP-occludin fluorescence recovery after photobleaching, but TNF treatment did not affect behavior of EGFP-occludin(ΔOCEL). Further, the free OCEL domain prevented TNF-induced acceleration of occludin fluorescence recovery, occludin endocytosis, and barrier loss. OCEL mutated within a recently proposed ZO-1-binding domain (K433) could not inhibit TNF effects, but OCEL mutated within the ZO-1 SH3-GuK-binding region (K485/K488) remained functional. We conclude that OCEL-mediated occludin interactions are essential for limiting paracellular macromolecular flux. Moreover, our data implicate interactions mediated by the OCEL K433 region as an effector of TNF-induced barrier regulation.
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Affiliation(s)
| | | | - Harsha Rajapakse
- Department of Pathology, The University of Chicago, Chicago, IL 60637
| | - David R. Raleigh
- Department of Pathology, The University of Chicago, Chicago, IL 60637
| | - Yitang Wang
- Department of Pathology, The University of Chicago, Chicago, IL 60637
| | - Yingmin Wang
- Department of Pathology, The University of Chicago, Chicago, IL 60637
| | - Amulya Lingaraju
- Department of Pathology, The University of Chicago, Chicago, IL 60637
| | - Juanmin Zha
- Department of Pathology, The University of Chicago, Chicago, IL 60637
| | - Elliot Abbott
- Department of Pathology, The University of Chicago, Chicago, IL 60637
| | - Erin M. McAuley
- Department of Pathology, The University of Chicago, Chicago, IL 60637
| | - Lydia A. Breskin
- Department of Pathology, The University of Chicago, Chicago, IL 60637
| | - Licheng Wu
- Department of Pathology, The University of Chicago, Chicago, IL 60637
| | - Kenneth Anderson
- Department of Pathology, The University of Chicago, Chicago, IL 60637
| | - Jerrold R. Turner
- Department of Pathology, The University of Chicago, Chicago, IL 60637
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Minoxidil sulfate induced the increase in blood-brain tumor barrier permeability through ROS/RhoA/PI3K/PKB signaling pathway. Neuropharmacology 2013; 75:407-15. [PMID: 23973310 DOI: 10.1016/j.neuropharm.2013.08.004] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2013] [Revised: 07/31/2013] [Accepted: 08/10/2013] [Indexed: 11/21/2022]
Abstract
Adenosine 5'-triphosphate-sensitive potassium channel (KATP channel) activator, minoxidil sulfate (MS), can selectively increase the permeability of the blood-tumor barrier (BTB); however, the mechanism by which this occurs is still under investigation. Using a rat brain glioma (C6) model, we first examined the expression levels of occludin and claudin-5 at different time points after intracarotid infusion of MS (30 μg/kg/min) by western blotting. Compared to MS treatment for 0 min group, the protein expression levels of occludin and claudin-5 in brain tumor tissue of rats showed no changes within 1 h and began to decrease significantly after 2 h of MS infusion. Based on these findings, we then used an in vitro BTB model and selective inhibitors of diverse signaling pathways to investigate whether reactive oxygen species (ROS)/RhoA/PI3K/PKB pathway play a key role in the process of the increase of BTB permeability induced by MS. The inhibitor of ROS or RhoA or PI3K or PKB significantly attenuated the expression of tight junction (TJ) protein and the increase of the BTB permeability after 2 h of MS treatment. In addition, the significant increases in RhoA activity and PKB phosphorylation after MS administration were observed, which were partly inhibited by N-2-mercaptopropionyl glycine (MPG) or C3 exoenzyme or LY294002 pretreatment. The present study indicates that the activation of signaling cascades involving ROS/RhoA/PI3K/PKB in BTB was required for the increase of BTB permeability induced by MS. Taken together, all of these results suggested that MS might increase BTB permeability in a time-dependent manner by down-regulating TJ protein expression and this effect could be related to ROS/RhoA/PI3K/PKB signal pathway.
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TIMP-1 attenuates blood-brain barrier permeability in mice with acute liver failure. J Cereb Blood Flow Metab 2013; 33:1041-9. [PMID: 23532086 PMCID: PMC3705430 DOI: 10.1038/jcbfm.2013.45] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/21/2012] [Revised: 02/28/2013] [Accepted: 03/03/2013] [Indexed: 02/06/2023]
Abstract
Blood-brain barrier (BBB) dysfunction in acute liver failure (ALF) results in increased BBB permeability that often precludes the patients from obtaining a life-saving liver transplantation. It remains controversial whether matrix metalloproteinase-9 (MMP-9) from the injured liver contributes to the deregulation of BBB function in ALF. We selectively upregulated a physiologic inhibitor of MMP-9 (TIMP-1) with a single intracerebroventricular injection of TIMP-1 cDNA plasmids at 48 and 72 hours, or with pegylated-TIMP-1 protein. Acute liver failure was induced with tumor necrosis factor-α and D-(+)-galactosamine in mice. Permeability of BBB was assessed with sodium fluorescein (NaF) extravasation. We found a significant increase in TIMP-1 within the central nervous system (CNS) after the administration of TIMP-1 cDNA plasmids and that increased TIMP-1 within the CNS resulted in an attenuation of BBB permeability, a reduction in activation of epidermal growth factor receptor and p38 mitogen-activated protein kinase signals, and a restoration of the tight junction protein occludin in mice with experimental ALF. Pegylated TIMP-1 provided similar protection against BBB permeability in mice with ALF. Our results provided a proof of principle that MMP-9 contributes to the BBB dysfunction in ALF and suggests a potential therapeutic role of TIMP-1 in ALF.
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Bao J, Yura RE, Matters GL, Bradley SG, Shi P, Tian F, Bond JS. Meprin A impairs epithelial barrier function, enhances monocyte migration, and cleaves the tight junction protein occludin. Am J Physiol Renal Physiol 2013; 305:F714-26. [PMID: 23804454 DOI: 10.1152/ajprenal.00179.2012] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Meprin metalloproteases are highly expressed at the luminal interface of the intestine and kidney and in certain leukocytes. Meprins cleave a variety of substrates in vitro, including extracellular matrix proteins, adherens junction proteins, and cytokines, and have been implicated in a number of inflammatory diseases. The linkage between results in vitro and pathogenesis, however, has not been elucidated. The present study aimed to determine whether meprins are determinative factors in disrupting the barrier function of the epithelium. Active meprin A or meprin B applied to Madin-Darby canine kidney (MDCK) cell monolayers increased permeability to fluorescein isothiocyanate-dextran and disrupted immunostaining of the tight junction protein occludin but not claudin-4. Meprin A, but not meprin B, cleaved occludin in MDCK monolayers. Experiments with recombinant occludin demonstrated that meprin A cleaves the protein between Gly(100) and Ser(101) on the first extracellular loop. In vivo experiments demonstrated that meprin A infused into the mouse bladder increased the epithelium permeability to sodium fluorescein. Furthermore, monocytes from meprin knockout mice on a C57BL/6 background were less able to migrate through an MDCK monolayer than monocytes from their wild-type counterparts. These results demonstrate the capability of meprin A to disrupt epithelial barriers and implicate occludin as one of the important targets of meprin A that may modulate inflammation.
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Affiliation(s)
- Jialing Bao
- Dept. of Biochemistry and Molecular Biology, The Pennsylvania State Univ. College of Medicine, 500 University Dr., H171, Hershey, PA 17033, USA
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Cong X, Zhang Y, Yang NY, Li J, Ding C, Ding QW, Su YC, Mei M, Guo XH, Wu LL, Yu GY. Occludin is required for TRPV1-modulated paracellular permeability in the submandibular gland. J Cell Sci 2013; 126:1109-21. [PMID: 23345400 DOI: 10.1242/jcs.111781] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
Occludin plays an important role in maintaining tight junction barrier function in many types of epithelia. We previously reported that activation of transient receptor potential vanilloid subtype 1 (TRPV1) in rabbit submandibular gland promoted salivary secretion, partly by an increase in paracellular permeability. We have now explored the role of occludin in TRPV1-modulated paracellular permeability in a rat submandibular gland cell line SMG-C6. Both TRPV1 and occludin were expressed in SMG-C6 cells, and capsaicin induced redistribution of occludin, but not claudin-3, claudin-4 or E-cadherin, from the cell membrane into the cytoplasm. Capsaicin also decreased transepithelial electrical resistance (TER) and increased the Trypan Blue and FITC-dextran flux. Capsazepine (CPZ), a TRPV1 antagonist, inhibited the capsaicin-induced occludin redistribution and TER decrease. Moreover, occludin knockdown by shRNA suppressed, whereas occludin re-expression restored, the TER response to capsaicin. Mechanistically, TRPV1 activation increased ERK1/2 and MLC2 phosphorylation. PD98059, an ERK1/2 kinase inhibitor, abolished the capsaicin-induced MLC2 phosphorylation, whereas ML-7, an MLC2 kinase inhibitor, did not affect ERK1/2 phosphorylation, suggesting that ERK1/2 is the upstream signaling molecule of MLC2. Capsaicin also induced F-actin reorganization, which was abolished by CPZ, PD98059 and ML-7, indicating that TRPV1 activation altered F-actin organization in an ERK1/2- and MLC2-dependent manner. Furthermore, either PD98059 or ML-7 could abolish the capsaicin-induced TER response and occludin redistribution, whereas knockdown of ERK1/2 further confirmed that the TRPV1-modulated paracellular permeability was ERK1/2 dependent. Taken together, these results identified a crucial role of occludin in submandibular epithelial cells, and more importantly, demonstrated that occludin was required to mediate TRPV1-modulated paracellular permeability.
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Affiliation(s)
- Xin Cong
- Center for Salivary Gland Diseases of Peking University School and Hospital of Stomatology, Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Peking University Health Science Center and Key Laboratory of Molecular Cardiovascular Sciences, Ministry of Education, Beijing, China
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Comparative tight junction protein expressions in colonic Crohn’s disease, ulcerative colitis, and tuberculosis: a new perspective. Virchows Arch 2012; 460:261-70. [PMID: 22297703 DOI: 10.1007/s00428-012-1195-1] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2011] [Revised: 12/31/2011] [Accepted: 01/11/2012] [Indexed: 12/13/2022]
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35
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Yan J, Zhang Z, Shi H. HIF-1 is involved in high glucose-induced paracellular permeability of brain endothelial cells. Cell Mol Life Sci 2012; 69:115-28. [PMID: 21617913 PMCID: PMC11115066 DOI: 10.1007/s00018-011-0731-5] [Citation(s) in RCA: 78] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2011] [Revised: 04/22/2011] [Accepted: 05/09/2011] [Indexed: 01/04/2023]
Abstract
Experimental evidence from human patients and animal models of diabetes has demonstrated that hyperglycemia increases blood-brain barrier (BBB) permeability, which is associated with increased risk of neurological dysfunction. However, the mechanism underlying high glucose-induced BBB disruption is not understood. Here we investigated the role of hypoxia-inducible factor-1 (HIF-1) in high glucose-induced endothelial permeability in vitro using mouse brain microvascular endothelial cells (b.End3). Our results demonstrated that high glucose (30 mM) upregulated the protein level of HIF-1α, the regulatable subunit of HIF-1, and increased the transcriptional activity of HIF-1 in the endothelial cells. At the same time, high glucose increased the paracellular permeability associated with diminished expression and disrupted continuity of tight junction proteins occludin and zona occludens protein-1 (ZO-1) of the endothelial cells. Upregulating HIF-1 activity by cobalt chloride increased the paracellular permeability of the endothelial cells exposed to normal glucose (5.5 mM). In contrast, downregulating HIF-1 activity by HIF-1α inhibitors and HIF-1α specific siRNA ameliorated the increased paracellular permeability and the alterations of distribution pattern of occludin and ZO-1 induced by high glucose. In addition, high glucose increased expression of vascular endothelial growth factor (VEGF), a downstream gene of HIF-1. Inhibiting VEGF improved the expression pattern of occludin and ZO-1, and attenuated the endothelial leakage. Furthermore, key results were confirmed in human brain microvascular endothelial cells. These results strongly indicate that HIF-1 plays an important role in high glucose-induced BBB dysfunction. The results will help us understand the molecular mechanisms involved in hyperglycemia-induced BBB dysfunction and neurological outcomes.
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Affiliation(s)
- Jingqi Yan
- Department of Pharmacology and Toxicology, School of Pharmacy, University of Kansas, 1251 Wescoe Hall Drive, Malott Hall 5044, Lawrence, KS 66045 USA
| | - Ziyan Zhang
- Department of Pharmacology and Toxicology, School of Pharmacy, University of Kansas, 1251 Wescoe Hall Drive, Malott Hall 5044, Lawrence, KS 66045 USA
| | - Honglian Shi
- Department of Pharmacology and Toxicology, School of Pharmacy, University of Kansas, 1251 Wescoe Hall Drive, Malott Hall 5044, Lawrence, KS 66045 USA
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36
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Yan J, Zhou B, Taheri S, Shi H. Differential effects of HIF-1 inhibition by YC-1 on the overall outcome and blood-brain barrier damage in a rat model of ischemic stroke. PLoS One 2011; 6:e27798. [PMID: 22110762 PMCID: PMC3218033 DOI: 10.1371/journal.pone.0027798] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2011] [Accepted: 10/25/2011] [Indexed: 01/02/2023] Open
Abstract
Hypoxia-inducible factor 1 (HIF-1) is a master regulator of cellular adaptation to hypoxia and has been suggested as a potent therapeutic target in cerebral ischemia. Here we show in an ischemic stroke model of rats that inhibiting HIF-1 and its downstream genes by 3-(5'-hydroxymethyl-2'-furyl)-1-benzylindazole (YC-1) significantly increases mortality and enlarges infarct volume evaluated by MRI and histological staining. Interestingly, the HIF-1 inhibition remarkably ameliorates ischemia-induced blood-brain barrier (BBB) disruption determined by Evans blue leakage although it does not affect brain edema. The result demonstrates that HIF-1 inhibition has differential effects on ischemic outcomes and BBB permeability. It indicates that HIF-1 may have different functions in different brain cells. Further analyses show that ischemia upregulates HIF-1 and its downstream genes erythropoietin (EPO), vascular endothelial growth factor (VEGF), and glucose transporter (Glut) in neurons and brain endothelial cells and that YC-1 inhibits their expression. We postulate that HIF-1-induced VEGF increases BBB permeability while certain other proteins coded by HIF-1's downstream genes such as epo and glut provide neuroprotection in an ischemic brain. The results indicate that YC-1 lacks the potential as a cerebral ischemic treatment although it confers certain protection to the cerebral vascular system.
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Affiliation(s)
- Jingqi Yan
- Department of Pharmacology and Toxicology, University of Kansas, Lawrence, Kansas, United States of America
| | - Bo Zhou
- Department of Pharmacology and Toxicology, University of Kansas, Lawrence, Kansas, United States of America
| | - Saeid Taheri
- Department of Neurology, University of South Carolina, Columbia, South Carolina, United States of America
| | - Honglian Shi
- Department of Pharmacology and Toxicology, University of Kansas, Lawrence, Kansas, United States of America
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37
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Nguyen JH. Blood-brain barrier in acute liver failure. Neurochem Int 2011; 60:676-83. [PMID: 22100566 DOI: 10.1016/j.neuint.2011.10.012] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2011] [Revised: 10/20/2011] [Accepted: 10/26/2011] [Indexed: 12/16/2022]
Abstract
Brain edema remains a challenging obstacle in the management of acute liver failure (ALF). Cytotoxic mechanisms associated with brain edema have been well recognized, but evidence for vasogenic mechanisms in the pathogenesis of brain edema in ALF has been lacking. Recent reports have not only shown a role of matrix metalloproteinase-9 in the pathogenesis of brain edema in experimental ALF but have also found significant alterations in the tight junction elements including occludin and claudin-5, suggesting a vasogenic injury in the blood-brain barrier (BBB) integrity. This article reviews and explores the role of the paracellular tight junction proteins in the increased selective BBB permeability that leads to brain edema in ALF.
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Affiliation(s)
- Justin H Nguyen
- Division of Transplant Surgery, Department of Transplantation, Mayo Clinic, 4500 San Pablo Road, Jacksonville, FL 32224, United States.
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Muto S, Furuse M, Kusano E. Claudins and renal salt transport. Clin Exp Nephrol 2011; 16:61-7. [PMID: 22038258 DOI: 10.1007/s10157-011-0491-4] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2010] [Accepted: 01/03/2011] [Indexed: 11/25/2022]
Abstract
Tight junctions (TJs) are the most apical component of junctional complexes and regulate the movement of electrolytes and solutes by the paracellular pathway across epithelia. The defining ultrastructural features of TJs are strands of transmembrane protein particles that adhere to similar strands on adjacent cells. These strands are mainly composed of linearly polymerized integral membrane proteins called claudins. Claudins comprise a multigene family consisting of more than 20 members in mammals. Recent work has shown that claudins form barriers, determined by the paracellular electrical resistance and charge selectivity, and pores in the TJ strands. The paracellular pathways in renal tubular epithelia such as the proximal tubule, which reabsorbs the largest fraction of filtered NaCl and water, are important routes for the transport of electrolytes and water. Their transport characteristics vary among different nephron segments. Multiple claudins are expressed at TJs of individual nephron segments in a nephron segment-specific manner. Among them, claudin-2 is highly expressed at TJs of proximal tubules, which are leaky epithelia. Overexpression and knockdown of claudin-2 in epithelial cell lines, and knockout of the claudin-2 gene in mice, have demonstrated that claudin-2 forms high-conductance cation-selective pores in the proximal tubule. Here, we review the renal physiology of paracellular transport and the physiological roles of claudins in kidney function, especially claudin-2 and proximal tubule paracellular NaCl transport.
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Affiliation(s)
- Shigeaki Muto
- Division of Nephrology, Department of Internal Medicine, Jichi Medical University, Shimotsuke, Tochigi, 329-0498, Japan.
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Blasig IE, Bellmann C, Cording J, Del Vecchio G, Zwanziger D, Huber O, Haseloff RF. Occludin protein family: oxidative stress and reducing conditions. Antioxid Redox Signal 2011; 15:1195-219. [PMID: 21235353 DOI: 10.1089/ars.2010.3542] [Citation(s) in RCA: 103] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
The occludin-like proteins belong to a family of tetraspan transmembrane proteins carrying a marvel domain. The intrinsic function of the occludin family is not yet clear. Occludin is a unique marker of any tight junction and is found in polarized endothelial and epithelial tissue barriers, at least in the adult vertebrate organism. Occludin is able to oligomerize and to form tight junction strands by homologous and heterologous interactions, but has no direct tightening function. Its oligomerization is affected by pro- and antioxidative agents or processes. Phosphorylation of occludin has been described at multiple sites and is proposed to play a regulatory role in tight junction assembly and maintenance and, hence, to influence tissue barrier characteristics. Redox-dependent signal transduction mechanisms are among the pathways modulating occludin phosphorylation and function. This review discusses the novel concept that occludin plays a key role in the redox regulation of tight junctions, which has a major impact in pathologies related to oxidative stress and corresponding pharmacologic interventions.
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Affiliation(s)
- Ingolf E Blasig
- Leibniz-Institut für Molekulare Pharmakologie, Berlin-Buch, Germany.
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40
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Coisne C, Engelhardt B. Tight junctions in brain barriers during central nervous system inflammation. Antioxid Redox Signal 2011; 15:1285-303. [PMID: 21338320 DOI: 10.1089/ars.2011.3929] [Citation(s) in RCA: 136] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Homeostasis within the central nervous system (CNS) is a prerequisite to elicit proper neuronal function. The CNS is tightly sealed from the changeable milieu of the blood stream by the blood-brain barrier (BBB) and the blood-cerebrospinal fluid (CSF) barrier (BCSFB). Whereas the BBB is established by specialized endothelial cells of CNS microvessels, the BCSFB is formed by the epithelial cells of the choroid plexus. Both constitute physical barriers by a complex network of tight junctions (TJs) between adjacent cells. During many CNS inflammatory disorders, such as multiple sclerosis, human immunodeficiency virus infection, or Alzheimer's disease, production of pro-inflammatory cytokines, matrix metalloproteases, and reactive oxygen species are responsible for alterations of CNS barriers. Barrier dysfunction can contribute to neurological disorders in a passive way by vascular leakage of blood-borne molecules into the CNS and in an active way by guiding the migration of inflammatory cells into the CNS. Both ways may directly be linked to alterations in molecular composition, function, and dynamics of the TJ proteins. This review summarizes current knowledge on the cellular and molecular aspects of the functional and dysfunctional TJ complexes at the BBB and the BCSFB, with a particular emphasis on CNS inflammation and the role of reactive oxygen species.
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Affiliation(s)
- Caroline Coisne
- Theodor Kocher Institute, University of Bern, Bern, Switzerland.
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Alexander JS, Zivadinov R, Maghzi AH, Ganta VC, Harris MK, Minagar A. Multiple sclerosis and cerebral endothelial dysfunction: Mechanisms. ACTA ACUST UNITED AC 2011; 18:3-12. [PMID: 20663648 DOI: 10.1016/j.pathophys.2010.04.002] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2010] [Revised: 03/30/2010] [Accepted: 04/08/2010] [Indexed: 01/02/2023]
Abstract
Multiple sclerosis (MS) is believed to be an immune-mediated neurodegenerative disorder of the human central nervous system which usually affects younger adults with certain genetic backgrounds. The causes and cure for MS remain elusive. Based on the recent advances in our understanding of the pathogenic mechanisms of MS, it appears to represents a heterogeneous group of disorders with dissimilar pathophysiology and neuropathology. Currently, there is no unifying hypothesis to explain the pathogenesis of this complex disease. The three prevailing concepts on the pathogenesis of MS include viral, immunological, and vascular hypotheses. This review presents MS as a neuroinflammatory disease with a significant vascular component and examines the existing evidence for the role of cerebral endothelial cell dysfunction in the pathogenesis of this progressive central nervous system (CNS) inflammatory disorder.
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Affiliation(s)
- J Steven Alexander
- Department of Cellular and Molecular Physiology, Louisiana State University Health Sciences Center, Shreveport, LA 71130, USA
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Yu TX, Wang PY, Rao JN, Zou T, Liu L, Xiao L, Gorospe M, Wang JY. Chk2-dependent HuR phosphorylation regulates occludin mRNA translation and epithelial barrier function. Nucleic Acids Res 2011; 39:8472-87. [PMID: 21745814 PMCID: PMC3201881 DOI: 10.1093/nar/gkr567] [Citation(s) in RCA: 72] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Occludin is a transmembrane tight junction (TJ) protein that plays an important role in TJ assembly and regulation of the epithelial barrier function, but the mechanisms underlying its post-transcriptional regulation are unknown. The RNA-binding protein HuR modulates the stability and translation of many target mRNAs. Here, we investigated the role of HuR in the regulation of occludin expression and therefore in the intestinal epithelial barrier function. HuR bound the 3′-untranslated region of the occludin mRNA and enhanced occludin translation. HuR association with the occludin mRNA depended on Chk2-dependent HuR phosphorylation. Reduced HuR phosphorylation by Chk2 silencing or by reduction of Chk2 through polyamine depletion decreased HuR-binding to the occludin mRNA and repressed occludin translation, whereas Chk2 overexpression enhanced (HuR/occludin mRNA) association and stimulated occludin expression. In mice exposed to septic stress induced by cecal ligation and puncture, Chk2 levels in the intestinal mucosa decreased, associated with an inhibition of occludin expression and gut barrier dysfunction. These results indicate that HuR regulates occludin mRNA translation through Chk2-dependent HuR phosphorylation and that this influence is crucial for maintenance of the epithelial barrier integrity in the intestinal tract.
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Affiliation(s)
- Ting-Xi Yu
- Cell Biology Group, Department of Surgery, University of Maryland School of Medicine, Baltimore Street, Baltimore, MD 21201, USA
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Al-Sadi R, Khatib K, Guo S, Ye D, Youssef M, Ma T. Occludin regulates macromolecule flux across the intestinal epithelial tight junction barrier. Am J Physiol Gastrointest Liver Physiol 2011; 300:G1054-64. [PMID: 21415414 PMCID: PMC3119114 DOI: 10.1152/ajpgi.00055.2011] [Citation(s) in RCA: 288] [Impact Index Per Article: 22.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Defective intestinal epithelial tight junction (TJ) barrier has been shown to be an important pathogenic factor contributing to the development of intestinal inflammation. The expression of occludin is markedly decreased in intestinal permeability disorders, including in Crohn's disease, ulcerative colitis, and celiac disease, suggesting that the decrease in occludin expression may play a role in the increase in intestinal permeability. The purpose of this study was to delineate the involvement of occludin in intestinal epithelial TJ barrier by selective knock down of occludin in in vitro (filter-grown Caco-2 monolayers) and in vivo (recycling perfusion of mouse intestine) intestinal epithelial models. Our results indicated that occludin small-interfering RNA (siRNA) transfection causes an increase in transepithelial flux of various-sized probes, including urea, mannitol, inulin, and dextran, across the Caco-2 monolayers, without affecting the transepithelial resistance. The increase in relative flux rate was progressively greater for larger-sized probes, indicating that occludin depletion has the greatest effect on the flux of large macromolecules. siRNA-induced knock down of occludin in mouse intestine in vivo also caused an increase in intestinal permeability to dextran but did not affect intestinal tissue transepithelial resistance. In conclusion, these results show for the first time that occludin depletion in intestinal epithelial cells in vitro and in vivo leads to a selective or preferential increase in macromolecule flux, suggesting that occludin plays a crucial role in the maintenance of TJ barrier through the large-channel TJ pathway, the pathway responsible for the macromolecule flux.
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Affiliation(s)
- Rana Al-Sadi
- 1Department of Internal Medicine, University of New Mexico, Albuquerque; and
| | - Khaldun Khatib
- 1Department of Internal Medicine, University of New Mexico, Albuquerque; and
| | - Shuhong Guo
- 1Department of Internal Medicine, University of New Mexico, Albuquerque; and
| | - Dongmei Ye
- 1Department of Internal Medicine, University of New Mexico, Albuquerque; and
| | - Moustafa Youssef
- 1Department of Internal Medicine, University of New Mexico, Albuquerque; and
| | - Thomas Ma
- 1Department of Internal Medicine, University of New Mexico, Albuquerque; and ,2Albuquerque Veterans Affairs Medical Center, Albuquerque, New Mexico
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Gu YT, Xue YX, Wei XY, Zhang H, Li Y. Calcium-activated potassium channel activator down-regulated the expression of tight junction protein in brain tumor model in rats. Neurosci Lett 2011; 493:140-4. [PMID: 21334421 DOI: 10.1016/j.neulet.2011.02.029] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2010] [Revised: 01/26/2011] [Accepted: 02/13/2011] [Indexed: 11/30/2022]
Abstract
This study was performed to investigate the mechanism of the blood-brain tumor-barrier (BTB) permeability increase, which was induced by NS1619, a selective K(Ca) channel activator. Using a rat brain glioma (C6) model, we exam the expression of ZO-1 and occludin in mRNA and protein level at different time point after intracarotid infusion of NS1619 (30 μg/kg/min) to tumor sites via RT-PCR and Western blot analysis. The mRNA and protein expression of ZO-1 and occludin had no great change before infusion and began to decrease significantly after 2 h NS1619 infusion, which was significantly attenuated by reactive oxygen species (ROS) scavenger (N-2-mercaptopropionyl glycine, MPG). In addition, MPG also significantly inhibited the increase of BTB permeability and malonaldehyde (MDA) level induced by NS1619. This led to the conclusion that NS1619 could time-dependently increase the BTB permeability by down-regulating the expression of tight junction protein, and this effect could be reversed by ROS.
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Affiliation(s)
- Yan-ting Gu
- Department of Physiology, Life Science and Biology Pharmacopedia Institution, Shenyang Pharmaceutical University, Shenyang 110016, Liaoning Province, PR China.
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Tam SJ, Watts RJ. Connecting vascular and nervous system development: angiogenesis and the blood-brain barrier. Annu Rev Neurosci 2011; 33:379-408. [PMID: 20367445 DOI: 10.1146/annurev-neuro-060909-152829] [Citation(s) in RCA: 134] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The vascular and nervous systems share a common necessity of circuit formation to coordinate nutrient and information transfer, respectively. Shared developmental principles have evolved to orchestrate the formation of both the vascular and the nervous systems. This evolution is highlighted by the identification of specific guidance cues that direct both systems to their target tissues. In addition to sharing cellular and molecular signaling events during development, the vascular and nervous systems also form an intricate interface within the central nervous system called the neurovascular unit. Understanding how the neurovascular unit develops and functions, and more specifically how the blood-brain barrier within this unit is established, is of utmost importance. We explore the history, recent discoveries, and unanswered questions surrounding the relationship between the vascular and nervous systems with a focus on developmental signaling cues that guide network formation and establish the interface between these two systems.
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Affiliation(s)
- Stephen J Tam
- Neurodegeneration Labs, Department of Neuroscience, Genentech, Inc., South San Francisco, California 94080, USA
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Redzic Z. Molecular biology of the blood-brain and the blood-cerebrospinal fluid barriers: similarities and differences. Fluids Barriers CNS 2011; 8:3. [PMID: 21349151 PMCID: PMC3045361 DOI: 10.1186/2045-8118-8-3] [Citation(s) in RCA: 251] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2010] [Accepted: 01/18/2011] [Indexed: 01/11/2023] Open
Abstract
Efficient processing of information by the central nervous system (CNS) represents an important evolutionary advantage. Thus, homeostatic mechanisms have developed that provide appropriate circumstances for neuronal signaling, including a highly controlled and stable microenvironment. To provide such a milieu for neurons, extracellular fluids of the CNS are separated from the changeable environment of blood at three major interfaces: at the brain capillaries by the blood-brain barrier (BBB), which is localized at the level of the endothelial cells and separates brain interstitial fluid (ISF) from blood; at the epithelial layer of four choroid plexuses, the blood-cerebrospinal fluid (CSF) barrier (BCSFB), which separates CSF from the CP ISF, and at the arachnoid barrier. The two barriers that represent the largest interface between blood and brain extracellular fluids, the BBB and the BCSFB, prevent the free paracellular diffusion of polar molecules by complex morphological features, including tight junctions (TJs) that interconnect the endothelial and epithelial cells, respectively. The first part of this review focuses on the molecular biology of TJs and adherens junctions in the brain capillary endothelial cells and in the CP epithelial cells. However, normal function of the CNS depends on a constant supply of essential molecules, like glucose and amino acids from the blood, exchange of electrolytes between brain extracellular fluids and blood, as well as on efficient removal of metabolic waste products and excess neurotransmitters from the brain ISF. Therefore, a number of specific transport proteins are expressed in brain capillary endothelial cells and CP epithelial cells that provide transport of nutrients and ions into the CNS and removal of waste products and ions from the CSF. The second part of this review concentrates on the molecular biology of various solute carrier (SLC) transport proteins at those two barriers and underlines differences in their expression between the two barriers. Also, many blood-borne molecules and xenobiotics can diffuse into brain ISF and then into neuronal membranes due to their physicochemical properties. Entry of these compounds could be detrimental for neural transmission and signalling. Thus, BBB and BCSFB express transport proteins that actively restrict entry of lipophilic and amphipathic substances from blood and/or remove those molecules from the brain extracellular fluids. The third part of this review concentrates on the molecular biology of ATP-binding cassette (ABC)-transporters and those SLC transporters that are involved in efflux transport of xenobiotics, their expression at the BBB and BCSFB and differences in expression in the two major blood-brain interfaces. In addition, transport and diffusion of ions by the BBB and CP epithelium are involved in the formation of fluid, the ISF and CSF, respectively, so the last part of this review discusses molecular biology of ion transporters/exchangers and ion channels in the brain endothelial and CP epithelial cells.
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Affiliation(s)
- Zoran Redzic
- Department of Physiology, Faculty of Medicine, Kuwait University, SAFAT 13110, Kuwait.
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Liu S, Kuo W, Yang W, Liu W, Gibson GA, Dorko K, Watkins SC, Strom SC, Wang T. The second extracellular loop dictates Occludin-mediated HCV entry. Virology 2010; 407:160-70. [PMID: 20822789 PMCID: PMC2946412 DOI: 10.1016/j.virol.2010.08.009] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2010] [Revised: 07/18/2010] [Accepted: 08/12/2010] [Indexed: 12/20/2022]
Abstract
Recent findings have implicated tight junction (TJ) protein Occludin (OCLN) as an essential factor for hepatitis C virus (HCV) to enter human hepatocytes. To gain insights into OCLN-mediated HCV entry, we created a panel of OCLN deletion mutants and found that without impairing OCLN's cell surface localization, removal of the extracellular loop 2 (EL2) from OCLN abolished both its ability to mediate HIV-HCV pseudotypes' (HCVpp) entry as well as its ability to coprecipitate HCV glycoprotein E2. Recombinant OCLN EL2, however, failed to robustly bind soluble E2 (sE2) in pull-down assays. Subsequent studies revealed that OCLN formed complex with Dynamin II, an important GTPase for endocytosis, in an EL2-dependent fashion. HCVpp, as well as cell culture grown HCV (HCVcc), was sensitive to Dynamin knockdown or inhibition. We conclude that OCLN EL2 dictates the Dynamin-dependent HCV entry. Furthermore, OCLN could function to bridge virions to Dynamin-dependent endocytic machineries.
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Affiliation(s)
- Shufeng Liu
- Department of Infectious Diseases and Microbiology, University of Pittsburgh, Pittsburgh, PA 15261
| | - Wayne Kuo
- Department of Infectious Diseases and Microbiology, University of Pittsburgh, Pittsburgh, PA 15261
| | - Wei Yang
- Institute of Pathogen Biology, Chinese Academy of Medical Sciences, Peking Union Medical College, Tsinghua University, Beijing, China
| | - Weiqun Liu
- Department of Infectious Diseases and Microbiology, University of Pittsburgh, Pittsburgh, PA 15261
| | - Gregory A. Gibson
- Department of Cell Biology and Physiology, University of Pittsburgh, Pittsburgh, PA 15261
| | - Kenneth Dorko
- Department of Pathology, University of Pittsburgh, Pittsburgh, PA 15261
| | - Simon C. Watkins
- Department of Cell Biology and Physiology, University of Pittsburgh, Pittsburgh, PA 15261
| | - Stephen C. Strom
- Department of Pathology, University of Pittsburgh, Pittsburgh, PA 15261
| | - Tianyi Wang
- Department of Infectious Diseases and Microbiology, University of Pittsburgh, Pittsburgh, PA 15261
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Kosovac K, Brenmoehl J, Holler E, Falk W, Schoelmerich J, Hausmann M, Rogler G. Association of the NOD2 genotype with bacterial translocation via altered cell-cell contacts in Crohn's disease patients. Inflamm Bowel Dis 2010; 16:1311-21. [PMID: 20232407 DOI: 10.1002/ibd.21223] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
BACKGROUND Recent insights into the pathogenesis of Crohn's disease (CD) point to an important role of the mucosal barrier and intestinal microflora that may induce a chronic inflammation after crossing the intestinal barrier. The first detected susceptibility gene for CD, NOD2, is a pattern recognition receptor (PRR) for the recognition of the bacterial cell wall component muramyldipeptide (MDP). Binding of MDP to NOD2 is followed by activation of proinflammatory pathways mainly regulated by nuclear factor kappa B (NF-kappaB). In this study we investigated whether impaired recognition of MDP via NOD2 variants is associated with increased bacterial translocation across the epithelial barrier and whether this is followed by increased or decreased NF-kappaB activation. METHODS NOD2 variants were analyzed in 36 CD patients and 30 controls. Endotoxin was stained by immunohistochemistry in 30 intestinal biopsies from patients carrying NOD2 variants (NOD2-mut) or being NOD2 wildtype (WT). Junctional proteins were visualized by immunofluorescence and quantified by Western blotting. NF-kappaB activation was analyzed by immunohistochemistry in specimens from NOD2-WT and NOD2-mut CD and control patients. RESULTS We demonstrated the increased presence of endotoxin in the mucosal lamina propria of CD patients carrying NOD2 variants. This was associated with an altered composition of epithelial cell-cell contacts. Patients carrying NOD2 variants displayed increased NF-kappaB activation in the mucosa. CONCLUSIONS This study for the first time demonstrates that translocation of luminal bacteria and/or bacterial products into the intestinal mucosa is increased in patients carrying NOD2 variants, leading to higher activation of proinflammatory signaling cascades.
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Affiliation(s)
- Katrin Kosovac
- University of Regensburg, Department of Internal Medicine I, Regensburg, Germany.
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Raikwar NS, Vandewalle A, Thomas CP. Nedd4-2 interacts with occludin to inhibit tight junction formation and enhance paracellular conductance in collecting duct epithelia. Am J Physiol Renal Physiol 2010; 299:F436-44. [PMID: 20504882 DOI: 10.1152/ajprenal.00674.2009] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Nedd4-2, a E3 ubiquitin ligase, regulates epithelial sodium channel-mediated transcellular Na(+) transport in the collecting duct. We investigated the effect of Nedd4-2 on the junctional complex and paracellular conductance in mpkCCD(c14) cells, a collecting duct cell line. We demonstrate that Nedd4-2 coimmunoprecipitated with and reduced the expression of transfected occludin in HEK293 cells. This interaction was mediated via a conserved PY motif in the COOH terminus of occludin and mutation of this PY motif increased the half-life of transfected occludin in HEK293 cells from 6.4 to 11.4 h. We demonstrate that Nedd4-2 ubiquitinates occludin, which was not seen when a catalytically inactive form of Nedd4-2 was used. Overexpression of Nedd4-2 in mpkCCD(c14) cells reduced occludin at the tight junction and transiently increased paracellular conductance in a Ca(2+) switch assay consistent with a delay in the formation of tight junctions. Conversely, siRNA-mediated knockdown of Nedd4-2 increased occludin levels and reduced paracellular conductance. In summary, we demonstrate that Nedd4-2 plays a role in tight junction assembly and the regulation of paracellular conductance in the collecting duct.
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Affiliation(s)
- Nandita S Raikwar
- Department of Internal Medicine, University of Iowa College of Medicine, Iowa City, 52242, USA
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Lischper M, Beuck S, Thanabalasundaram G, Pieper C, Galla HJ. Metalloproteinase mediated occludin cleavage in the cerebral microcapillary endothelium under pathological conditions. Brain Res 2010; 1326:114-27. [DOI: 10.1016/j.brainres.2010.02.054] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2009] [Revised: 01/26/2010] [Accepted: 02/18/2010] [Indexed: 10/19/2022]
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