51
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Negri AL, Del Valle EE. Role of claudins in idiopathic hypercalciuria and renal lithiasis. Int Urol Nephrol 2022; 54:2197-2204. [PMID: 35084652 DOI: 10.1007/s11255-022-03119-2] [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: 07/14/2021] [Accepted: 01/11/2022] [Indexed: 11/25/2022]
Abstract
Paracellular transport in the kidney is mediated by a family of proteins located in the tight junctions called claudins which confers its ionic selectivity. Claudin-2 is highly expressed in the proximal tubule and descending limb of Henle and mediate paracellular reabsorption of sodium and calcium cations. In the thick ascending limb of Henle (TALH) calcium is reabsorbed by a paracellular channel formed by Claudin-16 and-19. Claudin-16 mediates cationic permeability while Claudin-19 increases the cationic selectivity of Claudin-16 by blocking anionic permeability. On the other hand, Claudin 14, that is also located in TALH, inhibits the paracellular permeability of Claudin-16 to calcium. Recent wide genomic association analysis studies have detected four common synonymous variants (genetic polymorphisms of a single nucleotide, SNPs) at the locus of Claudin-14 gene that were significantly associated with the presence of renal lithiasis. Another study of wide genomic association and nephrolithiasis was carried out in the general population but including chromosome X, where claudin-2 gene is located. They detected nine SNPs that had a significant association with renal lithiasis risk. A greater knowledge of the paracellular pathway controlled by claudins and its regulation will allow us to develop future new treatments for idiopathic hypercalciuria and renal lithiasis.
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Affiliation(s)
- Armando Luis Negri
- Institute for Metabolic Research, Faculty of Medicine, Del Salvador University, Libertad 836, 1 Floor, 1012, Buenos Aires, Argentina.
| | - Elisa Elena Del Valle
- Institute for Metabolic Research, Faculty of Medicine, Del Salvador University, Libertad 836, 1 Floor, 1012, Buenos Aires, Argentina
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52
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Menaceur C, Gosselet F, Fenart L, Saint-Pol J. The Blood-Brain Barrier, an Evolving Concept Based on Technological Advances and Cell-Cell Communications. Cells 2021; 11:cells11010133. [PMID: 35011695 PMCID: PMC8750298 DOI: 10.3390/cells11010133] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2021] [Revised: 12/27/2021] [Accepted: 12/30/2021] [Indexed: 02/07/2023] Open
Abstract
The construction of the blood–brain barrier (BBB), which is a natural barrier for maintaining brain homeostasis, is the result of a meticulous organisation in space and time of cell–cell communication processes between the endothelial cells that carry the BBB phenotype, the brain pericytes, the glial cells (mainly the astrocytes), and the neurons. The importance of these communications for the establishment, maturation and maintenance of this unique phenotype had already been suggested in the pioneering work to identify and demonstrate the BBB. As for the history of the BBB, the evolution of analytical techniques has allowed knowledge to evolve on the cell–cell communication pathways involved, as well as on the role played by the cells constituting the neurovascular unit in the maintenance of the BBB phenotype, and more particularly the brain pericytes. This review summarises the key points of the history of the BBB, from its origin to the current knowledge of its physiology, as well as the cell–cell communication pathways identified so far during its development, maintenance, and pathophysiological alteration.
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53
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Wang J, Zheng B, Yang S, Zheng H, Wang J. Opicapone Protects Against Hyperhomocysteinemia-Induced Increase in Blood-Brain Barrier Permeability. Neurotox Res 2021; 39:2018-2028. [PMID: 34709593 DOI: 10.1007/s12640-021-00429-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Revised: 09/28/2021] [Accepted: 10/06/2021] [Indexed: 10/20/2022]
Abstract
Hyperhomocysteinemia (HHcy)-related brain vascular disorders and brain endothelial dysfunction are important characteristics of the pathogeneses of subarachnoid hemorrhage and stroke. Upregulated homocysteine (Hcy) can impair the integrity of the blood-brain barrier (BBB). Opicapone has been recently licensed for the management of Parkinson's disease (PD); however, it is unknown whether it possesses a protective effect in brain vessels against HHcy. To investigate the beneficial effects of Opicapone on BBB permeability against HHcy, we carried out both in vivo and in vitro experiments. Mice were allocated into four groups: the Control, Opicapone, HHcy, and HHcy + Opicapone. Interestingly, we found that the administration of Opicapone attenuated the increased BBB permeability in Hcy-treated mice, as determined by sodium fluorescein staining. The immunofluorescence staining showed that Opicapone prevented homocysteine-induced reduction of claudin-2 in the mice cortices. The in situ zymography assay revealed that Opicapone suppressed homocysteine-increased matrix metalloproteinases (MMPs) activity in the cortices. In bEnd.3 brain endothelial cells, Opicapone treatment ameliorated homocysteine-induced lactate dehydrogenase (LDH) release and expression of matrix metalloproteinase-2 (MMP-2) and matrix metalloproteinase-9 (MMP-9). Furthermore, Opicapone alleviated homocysteine-induced decrease in claudin-2 level in bEnd.3 cells. In summary, our results show that Opicapone protects against HHcy-induced BBB permeability by reducing the expression and gelatinase activity of MMPs, and increasing the expression of claudin-2.
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Affiliation(s)
- Jian Wang
- Department of Neurology, Ya'an Peoples Hospital, Ya'an, 625000, Sichuan, China
| | - Bo Zheng
- Department of Neurology, Ya'an Peoples Hospital, Ya'an, 625000, Sichuan, China
| | - Shu Yang
- Department of Neurology, The Affiliated Hospital of University of Electronic Science and Technology, Sichuan Provincial People's Hospital, Chengdu, 610000, Sichuan, China
| | - Hui Zheng
- Department of Neurology, Chengdu First People's Hospital, Chengdu, 610000, Sichuan, China.
| | - Jianhong Wang
- Department of Neurology, The Affiliated Hospital of University of Electronic Science and Technology, Sichuan Provincial People's Hospital, Chengdu, 610000, Sichuan, China.
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54
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Oda Y, Takahashi C, Harada S, Nakamura S, Sun D, Kiso K, Urata Y, Miyachi H, Fujiyoshi Y, Honigmann A, Uchida S, Ishihama Y, Toyoshima F. Discovery of anti-inflammatory physiological peptides that promote tissue repair by reinforcing epithelial barrier formation. SCIENCE ADVANCES 2021; 7:eabj6895. [PMID: 34788088 PMCID: PMC8597994 DOI: 10.1126/sciadv.abj6895] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/26/2021] [Accepted: 09/28/2021] [Indexed: 05/10/2023]
Abstract
Epithelial barriers that prevent dehydration and pathogen invasion are established by tight junctions (TJs), and their disruption leads to various inflammatory diseases and tissue destruction. However, a therapeutic strategy to overcome TJ disruption in diseases has not been established because of the lack of clinically applicable TJ-inducing molecules. Here, we found TJ-inducing peptides (JIPs) in mice and humans that corresponded to 35 to 42 residue peptides of the C terminus of alpha 1-antitrypsin (A1AT), an acute-phase anti-inflammatory protein. JIPs were inserted into the plasma membrane of epithelial cells, which promoted TJ formation by directly activating the heterotrimeric G protein G13. In a mouse intestinal epithelial injury model established by dextran sodium sulfate, mouse or human JIP administration restored TJ integrity and strongly prevented colitis. Our study has revealed TJ-inducing anti-inflammatory physiological peptides that play a critical role in tissue repair and proposes a previously unidentified therapeutic strategy for TJ-disrupted diseases.
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Affiliation(s)
- Yukako Oda
- Department of Biosystems Science, Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto 606-8507, Japan
| | - Chisato Takahashi
- Department of Molecular and Cellular BioAnalysis, Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto 606-8501, Japan
- Laboratory of Analytical Chemistry, Faculty of Pharmaceutical Sciences, Doshisha Women’s College of Liberal Arts, Kyoto 610-0395, Japan
| | - Shota Harada
- Laboratory of Human Interface, Graduate School of Systems Life Sciences, Kyushu University, Fukuoka 819-0395, Japan
| | - Shun Nakamura
- Cellular and Structural Physiology Laboratory, Advanced Research Institute, Tokyo Medical and Dental University, Tokyo 113-8510, Japan
- CeSPIA Inc., Tokyo 100-0004, Japan
| | - Daxiao Sun
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden 01309, Germany
| | - Kazumi Kiso
- Department of Biosystems Science, Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto 606-8507, Japan
| | - Yuko Urata
- Department of Biosystems Science, Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto 606-8507, Japan
| | - Hitoshi Miyachi
- Reproductive Engineering Team, Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto 606-8507, Japan
| | - Yoshinori Fujiyoshi
- Cellular and Structural Physiology Laboratory, Advanced Research Institute, Tokyo Medical and Dental University, Tokyo 113-8510, Japan
- CeSPIA Inc., Tokyo 100-0004, Japan
| | - Alf Honigmann
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden 01309, Germany
| | - Seiichi Uchida
- Laboratory of Human Interface, Graduate School of Systems Life Sciences, Kyushu University, Fukuoka 819-0395, Japan
| | - Yasushi Ishihama
- Department of Molecular and Cellular BioAnalysis, Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto 606-8501, Japan
| | - Fumiko Toyoshima
- Department of Biosystems Science, Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto 606-8507, Japan
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Ablation of Red Stable Transfected Claudin Expressing Canine Prostate Adenocarcinoma and Transitional Cell Carcinoma Cell Lines by C-CPE Gold-Nanoparticle-Mediated Laser Intervention. Int J Mol Sci 2021; 22:ijms222212289. [PMID: 34830170 PMCID: PMC8618062 DOI: 10.3390/ijms222212289] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2021] [Revised: 11/06/2021] [Accepted: 11/08/2021] [Indexed: 12/23/2022] Open
Abstract
Claudin (CLDN) proteins are commonly expressed in cancers and targeted in novel therapeutic approaches. The C-terminal of Clostridium perfringens enterotoxin (C-CPE) efficiently binds several claudins. In this study, recombinant C-CPE conjugated to gold nanoparticles (AuNPs) has been used for prostate adenocarcinoma (PAC) and transitional cell carcinoma (TCC) cell killing in vitro using gold-nanoparticle-mediated laser perforation (GNOME-LP). A PAC and TCC cell lines, as well as red fluorescence variants, allowing deep tissue imaging, were used. CLDN-3, -4, and -7 expression was confirmed by qPCR and immunofluorescences. The binding of C-CPE-AuNPs complexes on the cell surface was examined by scanning electron microscopy (SEM). Further, transcriptome analysis was carried out to evaluate the effect of C-CPE binder on the biological response of treated cells. Directed C-CPE-AuNP binding verified the capability to target CLDN receptors. Transcriptome analysis showed that C-CPE binding may activate immune and inflammatory responses but does not directly affect cell survival. Cancer cells ablation was demonstrated using a combination of GNOME-LP and C-CPE-AuNPs treatment reducing tumor cell viability to less than 10% depending on cell line. The fluorescent cell lines and the verified proof of concept in vitro provide the basis for perspective xenograft studies in an animal model.
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Claudin-9 constitutes tight junctions of folliculo-stellate cells in the anterior pituitary gland. Sci Rep 2021; 11:21642. [PMID: 34737342 PMCID: PMC8568902 DOI: 10.1038/s41598-021-01004-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Accepted: 10/20/2021] [Indexed: 12/27/2022] Open
Abstract
The anterior pituitary gland regulates growth, metabolism, and reproduction by secreting hormones. Folliculo-stellate (FS) cells are non-endocrine cells located among hormone-producing cells in the anterior pituitary glands. They form follicular lumens, which are sealed by tight junctions (TJs). Although FS cells are hypothesized to contribute to fine-tuning of endocrine cells, little is known about the exact roles of FS cells. Here, we investigated the molecular composition of TJs in FS cells. We demonstrated that occludin is a good marker for TJs in the pituitary gland and examined the structure of the lumens surrounded by FS cells. We also found that claudin-9 is a major component of TJs in the FS cells. In immunoelectron microscopy, claudin-9 was specifically localized at TJs of the FS cells. The expression of claudin-9 was gradually increased in the pituitary gland after birth, suggesting that claudin-9 is developmentally regulated and performs some specific functions on the paracellular barrier of follicles in the pituitary gland. Furthermore, we found that angulin-1, angulin-2, and tricellulin are localized at the tricellular contacts of the FS cells. Our findings provide a first comprehensive molecular profile of TJs in the FS cells, and may lead us towards unveiling the FS cell functions.
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57
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Yemanyi F, Bora K, Blomfield AK, Wang Z, Chen J. Wnt Signaling in Inner Blood-Retinal Barrier Maintenance. Int J Mol Sci 2021; 22:11877. [PMID: 34769308 PMCID: PMC8584977 DOI: 10.3390/ijms222111877] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2021] [Revised: 10/28/2021] [Accepted: 10/29/2021] [Indexed: 12/14/2022] Open
Abstract
The retina is a light-sensing ocular tissue that sends information to the brain to enable vision. The blood-retinal barrier (BRB) contributes to maintaining homeostasis in the retinal microenvironment by selectively regulating flux of molecules between systemic circulation and the retina. Maintaining such physiological balance is fundamental to visual function by facilitating the delivery of nutrients and oxygen and for protection from blood-borne toxins. The inner BRB (iBRB), composed mostly of inner retinal vasculature, controls substance exchange mainly via transportation processes between (paracellular) and through (transcellular) the retinal microvascular endothelium. Disruption of iBRB, characterized by retinal edema, is observed in many eye diseases and disturbs the physiological quiescence in the retina's extracellular space, resulting in vision loss. Consequently, understanding the mechanisms of iBRB formation, maintenance, and breakdown is pivotal to discovering potential targets to restore function to compromised physiological barriers. These unraveled targets can also inform potential drug delivery strategies across the BRB and the blood-brain barrier into retinas and brain tissues, respectively. This review summarizes mechanistic insights into the development and maintenance of iBRB in health and disease, with a specific focus on the Wnt signaling pathway and its regulatory role in both paracellular and transcellular transport across the retinal vascular endothelium.
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Affiliation(s)
| | | | | | | | - Jing Chen
- Department of Ophthalmology, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA; (F.Y.); (K.B.); (A.K.B.); (Z.W.)
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58
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Li J. Targeting claudins in cancer: diagnosis, prognosis and therapy. Am J Cancer Res 2021; 11:3406-3424. [PMID: 34354852] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2021] [Accepted: 06/18/2021] [Indexed: 11/09/2022] Open
Abstract
Increasing evidence has linked claudins to signal transduction and tumorigenesis. The expression of claudins is frequently dysregulated in the context of neoplastic transformation, suggesting their promise as biomarkers for diagnosis and prognosis or targets for treatment. Claudin binders (Clostridium perfringens enterotoxin and monoclonal antibody) have been tested in preclinical experiments, and some of them have progressed into clinical trials involving patients with certain cancers. However, the clinical development of many of these agents has not advanced to clinical applications. Herein, I review the current status of preclinical and clinical investigations of agents targeting claudins for diagnosis, prognosis and therapy. I also discuss the potential of combining claudin binders with other currently approved therapeutic agents.
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Affiliation(s)
- Jian Li
- Department of General Surgery, The Third Hospital of Mianyang, Sichuan Mental Health Center Mianyang 621000, Sichuan, China
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59
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Li J. Context-Dependent Roles of Claudins in Tumorigenesis. Front Oncol 2021; 11:676781. [PMID: 34354941 PMCID: PMC8329526 DOI: 10.3389/fonc.2021.676781] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2021] [Accepted: 07/05/2021] [Indexed: 12/16/2022] Open
Abstract
The barrier and fence functions of the claudin protein family are fundamental to tissue integrity and human health. Increasing evidence has linked claudins to signal transduction and tumorigenesis. The expression of claudins is frequently dysregulated in the context of neoplastic transformation. Studies have uncovered that claudins engage in nearly all aspects of tumor biology and steps of tumor development, suggesting their promise as targets for treatment or biomarkers for diagnosis and prognosis. However, claudins can be either tumor promoters or tumor suppressors depending on the context, which emphasizes the importance of taking various factors, including organ type, environmental context and genetic confounders, into account when studying the biological functions and targeting of claudins in cancer. This review discusses the complicated roles and intrinsic and extrinsic determinants of the context-specific effects of claudins in cancer.
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Affiliation(s)
- Jian Li
- Department of General Surgery, The Third Hospital of Mianyang, Sichuan Mental Health Center, Mianyang, China
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60
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Monaco A, Ovryn B, Axis J, Amsler K. The Epithelial Cell Leak Pathway. Int J Mol Sci 2021; 22:ijms22147677. [PMID: 34299297 PMCID: PMC8305272 DOI: 10.3390/ijms22147677] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2021] [Revised: 07/13/2021] [Accepted: 07/15/2021] [Indexed: 01/08/2023] Open
Abstract
The epithelial cell tight junction structure is the site of the transepithelial movement of solutes and water between epithelial cells (paracellular permeability). Paracellular permeability can be divided into two distinct pathways, the Pore Pathway mediating the movement of small ions and solutes and the Leak Pathway mediating the movement of large solutes. Claudin proteins form the basic paracellular permeability barrier and mediate the movement of small ions and solutes via the Pore Pathway. The Leak Pathway remains less understood. Several proteins have been implicated in mediating the Leak Pathway, including occludin, ZO proteins, tricellulin, and actin filaments, but the proteins comprising the Leak Pathway remain unresolved. Many aspects of the Leak Pathway, such as its molecular mechanism, its properties, and its regulation, remain controversial. In this review, we provide a historical background to the evolution of the Leak Pathway concept from the initial examinations of paracellular permeability. We then discuss current information about the properties of the Leak Pathway and present current theories for the Leak Pathway. Finally, we discuss some recent research suggesting a possible molecular basis for the Leak Pathway.
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Affiliation(s)
- Ashley Monaco
- Department of Biomedical Sciences, New York Institute of Technology College of Osteopathic Medicine, Northern Boulevard, Old Westbury, NY 11568, USA; (A.M.); (J.A.)
| | - Ben Ovryn
- Department of Physics, New York Institute of Technology, Northern Boulevard, Old Westbury, NY 11568, USA;
| | - Josephine Axis
- Department of Biomedical Sciences, New York Institute of Technology College of Osteopathic Medicine, Northern Boulevard, Old Westbury, NY 11568, USA; (A.M.); (J.A.)
| | - Kurt Amsler
- Department of Biomedical Sciences, New York Institute of Technology College of Osteopathic Medicine, Northern Boulevard, Old Westbury, NY 11568, USA; (A.M.); (J.A.)
- Correspondence: ; Tel.: +1-516-686-3716
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Abstract
Claudins are adhesion molecules located at the tight junctions between epithelial cells. A series of studies have now reported aberrant expression of claudin proteins in the context of neoplastic transformation, suggesting its role in tumorigenesis. However, the precise mechanisms are still not well understood. Studies on expression alterations of claudins have revealed a range of outcomes that reflect the complexity of claudins in terms of spatial localization, tumor type and stage of disease. The diverse and dynamic expression patterns of claudins in cancer are tightly controlled by a wide range of regulatory mechanisms, which are commonly modulated by oncogenic signaling pathways. The present review summarizes the recent knowledge describing the dysregulation of claudin expression in cancer and discusses the intrinsic and extrinsic determinants of the context-specific expression patterns of claudins.
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Hou X, Du HJ, Zhou J, Hu D, Wang YS, Li X. Role of Junctional Adhesion Molecule-C in the Regulation of Inner Endothelial Blood-Retinal Barrier Function. Front Cell Dev Biol 2021; 9:695657. [PMID: 34164405 PMCID: PMC8215391 DOI: 10.3389/fcell.2021.695657] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2021] [Accepted: 05/14/2021] [Indexed: 12/27/2022] Open
Abstract
Although JAM-C is abundantly expressed in the retinae and upregulated in choroidal neovascularization (CNV), it remains thus far poorly understood whether it plays a role in the blood-retinal barrier, which is critical to maintain the normal functions of the eye. Here, we report that JAM-C is highly expressed in retinal capillary endothelial cells (RCECs), and VEGF or PDGF-C treatment induced JAM-C translocation from the cytoplasm to the cytomembrane. Moreover, JAM-C knockdown in RCECs inhibited the adhesion and transmigration of macrophages from wet age-related macular degeneration (wAMD) patients to and through RCECs, whereas JAM-C overexpression in RCECs increased the adhesion and transmigration of macrophages from both wAMD patients and healthy controls. Importantly, the JAM-C overexpression-induced transmigration of macrophages from wAMD patients was abolished by the administration of the protein kinase C (PKC) inhibitor GF109203X. Of note, we found that the serum levels of soluble JAM-C were more than twofold higher in wAMD patients than in healthy controls. Mechanistically, we show that JAM-C overexpression or knockdown in RCECs decreased or increased cytosolic Ca2+ concentrations, respectively. Our findings suggest that the dynamic translocation of JAM-C induced by vasoactive molecules might be one of the mechanisms underlying inner endothelial BRB malfunction, and inhibition of JAM-C or PKC in RCECs may help maintain the normal function of the inner BRB. In addition, increased serum soluble JAM-C levels might serve as a molecular marker for wAMD, and modulating JAM-C activity may have potential therapeutic value for the treatment of BRB malfunction-related ocular diseases.
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Affiliation(s)
- Xu Hou
- Department of Ophthalmology, Eye Institute of Chinese PLA, Xijing Hospital, Fourth Military Medical University, Xi'an, China
| | - Hong-Jun Du
- Department of Ophthalmology, Eye Institute of Chinese PLA, Xijing Hospital, Fourth Military Medical University, Xi'an, China
| | - Jian Zhou
- Department of Ophthalmology, Eye Institute of Chinese PLA, Xijing Hospital, Fourth Military Medical University, Xi'an, China
| | - Dan Hu
- Department of Ophthalmology, Eye Institute of Chinese PLA, Xijing Hospital, Fourth Military Medical University, Xi'an, China
| | - Yu-Sheng Wang
- Department of Ophthalmology, Eye Institute of Chinese PLA, Xijing Hospital, Fourth Military Medical University, Xi'an, China
| | - Xuri Li
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China
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Yeh TY, Liu PH. Removal of a compressive mass causes a transient disruption of blood-brain barrier but a long-term recovery of spiny stellate neurons in the rat somatosensory cortex. Restor Neurol Neurosci 2021; 39:111-127. [PMID: 34024792 DOI: 10.3233/rnn-201085] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
BACKGROUND In the cranial cavity, a space-occupying mass such as epidural hematoma usually leads to compression of brain. Removal of a large compressive mass under the cranial vault is critical to the patients. OBJECTIVE The purpose of this study was to examine whether and to what extent epidural decompression of the rat primary somatosensory cortex affects the underlying microvessels, spiny stellate neurons and their afferent fibers. METHODS Rats received epidural decompression with preceding 1-week compression by implantation of a bead. The thickness of cortex was measured using brain coronal sections. The permeability of blood-brain barrier (BBB) was assessed by Evans Blue and immunoglobulin G extravasation. The dendrites and dendritic spines of the spiny stellate neurons were revealed by Golgi-Cox staining and analyzed. In addition, the thalamocortical afferent (TCA) fibers in the cortex were illustrated using anterograde tracing and examined. RESULTS The cortex gradually regained its thickness over time and became comparable to the sham group at 3 days after decompression. Although the diameter of cortical microvessels were unaltered, a transient disruption of the BBB was observed at 6 hours and 1 day after decompression. Nevertheless, no brain edema was detected. In contrast, the dendrites and dendritic spines of the spiny stellate neurons and the TCA fibers were markedly restored from 2 weeks to 3 months after decompression. CONCLUSIONS Epidural decompression caused a breakdown of the BBB, which was early-occurring and short-lasting. In contrast, epidural decompression facilitated a late-onset and prolonged recovery of the spiny stellate neurons and their afferent fibers.
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Affiliation(s)
- Tzu-Yin Yeh
- Department of Anatomy, Tzu Chi University, Hualien, Taiwan
| | - Pei-Hsin Liu
- Department of Anatomy, Tzu Chi University, Hualien, Taiwan.,Medical Physiology, Tzu Chi University, Hualien, Taiwan
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Taylor A, Warner M, Mendoza C, Memmott C, LeCheminant T, Bailey S, Christensen C, Keller J, Suli A, Mizrachi D. Chimeric Claudins: A New Tool to Study Tight Junction Structure and Function. Int J Mol Sci 2021; 22:ijms22094947. [PMID: 34066630 PMCID: PMC8124314 DOI: 10.3390/ijms22094947] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2021] [Revised: 05/02/2021] [Accepted: 05/04/2021] [Indexed: 12/11/2022] Open
Abstract
The tight junction (TJ) is a structure composed of multiple proteins, both cytosolic and membranal, responsible for cell–cell adhesion in polarized endothelium and epithelium. The TJ is intimately connected to the cytoskeleton and plays a role in development and homeostasis. Among the TJ’s membrane proteins, claudins (CLDNs) are key to establishing blood–tissue barriers that protect organismal physiology. Recently, several crystal structures have been reported for detergent extracted recombinant CLDNs. These structural advances lack direct evidence to support quaternary structure of CLDNs. In this article, we have employed protein-engineering principles to create detergent-independent chimeric CLDNs, a combination of a 4-helix bundle soluble monomeric protein (PDB ID: 2jua) and the apical—50% of human CLDN1, the extracellular domain that is responsible for cell–cell adhesion. Maltose-binding protein-fused chimeric CLDNs (MBP-CCs) used in this study are soluble proteins that retain structural and functional aspects of native CLDNs. Here, we report the biophysical characterization of the structure and function of MBP-CCs. MBP-fused epithelial cadherin (MBP-eCAD) is used as a control and point of comparison of a well-characterized cell-adhesion molecule. Our synthetic strategy may benefit other families of 4-α-helix membrane proteins, including tetraspanins, connexins, pannexins, innexins, and more.
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65
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Sugimoto K, Chiba H. The claudin-transcription factor signaling pathway. Tissue Barriers 2021; 9:1908109. [PMID: 33906582 PMCID: PMC8489944 DOI: 10.1080/21688370.2021.1908109] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
Claudins (CLDNs) represent major transmembrane proteins of tight junctions and contribute to the barrier function. They also serve as anchors for several signaling proteins, but the underlying molecular basis has yet to be established. The present review covers the recent progress in our understanding of the CLDN signaling pathway in health and disease. We discuss the functional relevance of phosphotyrosine motifs in the C-terminal cytoplasmic domain of CLDNs and define mutual regulation between CLDNs and Src-family kinases (SFKs). In addition, we focus on the crosstalk between CLDN and transcription factor signaling. We also describe how aberrant CLDN–transcription factor signaling promotes or inhibits cancer progression. We propose that a link between various cell adhesion molecules and transcription factors coordinates a range of physiological and pathological events via activation or suppression of target genes.
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Affiliation(s)
- Kotaro Sugimoto
- Department of Basic Pathology, Fukushima Medical University School of Medicine, Fukushima, Japan
| | - Hideki Chiba
- Department of Basic Pathology, Fukushima Medical University School of Medicine, Fukushima, Japan
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Sun X, Cui Y, Su Y, Gao Z, Diao X, Li J, Zhu X, Li D, Li Z, Wang C, Shi Y. Dietary Fiber Ameliorates Lipopolysaccharide-Induced Intestinal Barrier Function Damage in Piglets by Modulation of Intestinal Microbiome. mSystems 2021; 6:e01374-20. [PMID: 33824201 PMCID: PMC8547013 DOI: 10.1128/msystems.01374-20] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2020] [Accepted: 03/10/2021] [Indexed: 12/24/2022] Open
Abstract
Weaning of piglets is accompanied by intestinal inflammation, impaired intestinal barrier function, and intestinal microflora disorder. Regulating intestinal microflora structure can directly or indirectly affect intestinal health and host growth and development. However, whether dietary fiber (DF) affects the inflammatory response and barrier function by affecting the intestinal microflora and its metabolites is unclear. In this study, we investigated the role of intestinal microflora in relieving immune stress and maintaining homeostasis using piglets with lipopolysaccharide (LPS)-induced intestinal injury as a model. DF improved intestinal morphology and barrier function, inhibited the expression of inflammatory signal pathways (Toll-like receptor 2 [TLR2], TLR4, and NF-κB) and proinflammatory cytokines (interleukin 1β [IL-1β], IL-6, and tumor necrosis factor alpha [TNF-α]), and upregulated the expression of barrier-related genes (encoding claudin-1, occludin, and ZO-1). The contents of proinflammatory cytokines (IL-1β, IL-6, and TNF-α) and the activity of diamine oxidase in plasma were decreased. Meanwhile, DF had a strong effect on the composition and function of intestinal microflora at different taxonomic levels, the relative abundances of cellulolytic bacteria and anti-inflammatory bacteria were increased, and the concentrations of propionate, butyrate, and total short-chain fatty acids (SCFAs) in intestinal contents were increased. In addition, the correlation analysis also revealed the potential relationship between metabolites and certain intestinal microflora, as well as the relationship between metabolites and intestinal morphology, intestinal gene expression, and plasma cytokine levels. These results indicate that DF improves intestinal barrier function, in part, by altering intestinal microbiota composition and increasing the synthesis of SCFAs, which subsequently alleviate local and systemic inflammation.IMPORTANCE Adding DF to the diet of LPS-challenged piglets alleviated intestinal and systemic inflammation, improved intestinal barrier function, and ultimately alleviated the growth retardation of piglets. In addition, the addition of DF significantly increased the relative abundance of SCFA-producing bacteria and the production of SCFAs. We believe that the improvement of growth performance of piglets with LPS-induced injury can be attributed to the beneficial effects of DF on intestinal microflora and SCFAs, which reduced the inflammatory response in piglets, improving intestinal barrier function and enhancing body health. These research results provide a theoretical basis and guidance for the use of specific fiber sources in the diet to improve intestinal health and growth performance of piglets and thus alleviate weaning stress. Our data also provide insights for studying the role of DF in regulating gastrointestinal function in human infants.
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Affiliation(s)
- Xiao Sun
- College of Animal Science and Technology, Henan Agricultural University, Zhengzhou, China
| | - Yalei Cui
- College of Animal Science and Technology, Henan Agricultural University, Zhengzhou, China
- Henan Key Laboratory of Innovation and Utilization of Grassland Resources, Zhengzhou, China
- Henan Forage Engineering Technology Research Center, Zhengzhou, China
| | - Yingying Su
- College of Animal Science and Technology, Henan Agricultural University, Zhengzhou, China
| | - Zimin Gao
- College of Animal Science and Technology, Henan Agricultural University, Zhengzhou, China
| | - Xinying Diao
- College of Animal Science and Technology, Henan Agricultural University, Zhengzhou, China
| | - Ju Li
- Henan Yinfa Animal Husbandry Co., Xinzheng, China
| | - Xiaoyan Zhu
- College of Animal Science and Technology, Henan Agricultural University, Zhengzhou, China
- Henan Key Laboratory of Innovation and Utilization of Grassland Resources, Zhengzhou, China
- Henan Forage Engineering Technology Research Center, Zhengzhou, China
| | - Defeng Li
- College of Animal Science and Technology, Henan Agricultural University, Zhengzhou, China
- Henan Key Laboratory of Innovation and Utilization of Grassland Resources, Zhengzhou, China
- Henan Forage Engineering Technology Research Center, Zhengzhou, China
| | - Zhentian Li
- College of Animal Science and Technology, Henan Agricultural University, Zhengzhou, China
- Henan Key Laboratory of Innovation and Utilization of Grassland Resources, Zhengzhou, China
- Henan Forage Engineering Technology Research Center, Zhengzhou, China
| | - Chengzhang Wang
- College of Animal Science and Technology, Henan Agricultural University, Zhengzhou, China
- Henan Key Laboratory of Innovation and Utilization of Grassland Resources, Zhengzhou, China
- Henan Forage Engineering Technology Research Center, Zhengzhou, China
| | - Yinghua Shi
- College of Animal Science and Technology, Henan Agricultural University, Zhengzhou, China
- Henan Key Laboratory of Innovation and Utilization of Grassland Resources, Zhengzhou, China
- Henan Forage Engineering Technology Research Center, Zhengzhou, China
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67
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Brunner J, Ragupathy S, Borchard G. Target specific tight junction modulators. Adv Drug Deliv Rev 2021; 171:266-288. [PMID: 33617902 DOI: 10.1016/j.addr.2021.02.008] [Citation(s) in RCA: 65] [Impact Index Per Article: 21.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Revised: 02/08/2021] [Accepted: 02/10/2021] [Indexed: 02/07/2023]
Abstract
Intercellular tight junctions represent a formidable barrier against paracellular drug absorption at epithelia (e.g., nasal, intestinal) and the endothelium (e.g., blood-brain barrier). In order to enhance paracellular transport of drugs and increase their bioavailability and organ deposition, active excipients modulating tight junctions have been applied. First-generation of permeation enhancers (PEs) acted by unspecific interactions, while recently developed PEs address specific physiological mechanisms. Such target specific tight junction modulators (TJMs) have the advantage of a defined specific mechanism of action. To date, merely a few of these novel active excipients has entered into clinical trials, as their lack in safety and efficiency in vivo often impedes their commercialisation. A stronger focus on the development of such active excipients would result in an economic and therapeutic improvement of current and future drugs.
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Affiliation(s)
- Joël Brunner
- Section of Pharmaceutical Sciences, Institute of Pharmaceutical Sciences of Western Switzerland, University of Geneva, 1211 Geneva, Switzerland
| | - Sakthikumar Ragupathy
- Section of Pharmaceutical Sciences, Institute of Pharmaceutical Sciences of Western Switzerland, University of Geneva, 1211 Geneva, Switzerland
| | - Gerrit Borchard
- Section of Pharmaceutical Sciences, Institute of Pharmaceutical Sciences of Western Switzerland, University of Geneva, 1211 Geneva, Switzerland.
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68
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Cioanca AV, Wu C(S, Natoli R, Conway RM, McCluskey PJ, Jager MJ, Sitiwin EI, Eamegdool SS, Madigan MC. The role of melanocytes in the human choroidal microenvironment and inflammation: Insights from the transcriptome. Pigment Cell Melanoma Res 2021; 34:928-945. [DOI: 10.1111/pcmr.12972] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Revised: 02/22/2021] [Accepted: 03/13/2021] [Indexed: 12/23/2022]
Affiliation(s)
- Adrian V. Cioanca
- John Curtin School of Medical Research The Australian National University Canberra ACT Australia
| | - Chieh‐Lin (Stanley) Wu
- School of Optometry and Vision Science University of NSW Sydney NSW Australia
- Save Sight Institute University of Sydney Sydney NSW Australia
| | - Riccardo Natoli
- John Curtin School of Medical Research The Australian National University Canberra ACT Australia
| | - R. Max Conway
- Save Sight Institute University of Sydney Sydney NSW Australia
| | | | - Martine J Jager
- Department of Ophthalmology Leiden University Medical Center Leiden The Netherlands
| | | | - Steven S. Eamegdool
- Save Sight Institute University of Sydney Sydney NSW Australia
- Eye Genetics Research Unit Children’s Medical Research Institute Westmead Hospital Westmead NSW Australia
| | - Michele C. Madigan
- School of Optometry and Vision Science University of NSW Sydney NSW Australia
- Save Sight Institute University of Sydney Sydney NSW Australia
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69
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Zhong J, Yu R, Zhou Q, Liu P, Liu Z, Bian Y. Naringenin prevents TNF-α-induced gut-vascular barrier disruption associated with inhibiting the NF-κB-mediated MLCK/p-MLC and NLRP3 pathways. Food Funct 2021; 12:2715-2725. [PMID: 33667286 DOI: 10.1039/d1fo00155h] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The microvasculature endothelium accurately regulates the passage of molecules across the gut-vascular barrier (GVB), which plays an essential role in intestinal immunity. Naringenin is reported to have therapeutic potential against several intestinal disorders. However, the effect of naringenin on GVB disruption has been rarely studied. This study aims to investigate the effect of naringenin on GVB function and the potential mechanism. In the present study, the in vitro GVB disruption of rat intestinal microvascular endothelial cells (RIMVEC) was induced by 50 ng mL-1 of tumor necrosis factor-α (TNF-α). The integrity of the in vitro GVB was determined by Evans blue (EB)-albumin efflux assay and trans-endothelial electrical resistance (TER). Meanwhile, the expression of tight junction proteins and the related NF-κB, MLCK/p-MLC and NLRP3 pathways were determined using enzyme-linked immunosorbent assay (ELISA), real-time quantitative polymerase chain reaction (RT-qPCR), western blot analysis and immunofluorescence. The results show that naringenin (100 μM) inhibits TNF-α-induced interleukin (IL)-6 hypersecretion, alleviates GVB disruption and mitigates the change in the tight junction protein expression pattern. Naringenin inhibits the GVB-disruption-associated activation of the MLCK/p-MLC system and TLR4/NF-κB/NLRP3 pathways. Furthermore, naringenin shows a similar effect to that of NF-κB inhibitor Bay 11-7082 in reducing the TNF-α-induced activation of NLRP3, p-MLC and secondary GVB disruption. The results suggest that naringenin evidently alleviates TNF-α-induced in vitro GVB disruption via the maintenance of a tight junction protein pattern, partly with the inhibition of the NF-κB-mediated MLCK/p-MLC and NLRP3 pathway activation.
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Affiliation(s)
- Jia Zhong
- Division of Traditional Chinese Veterinary Medicine, College of Veterinary Medicine, China Agricultural University, Beijing 100193, P. R. China.
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70
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Winkler A, Wrzos C, Haberl M, Weil MT, Gao M, Möbius W, Odoardi F, Thal DR, Chang M, Opdenakker G, Bennett JL, Nessler S, Stadelmann C. Blood-brain barrier resealing in neuromyelitis optica occurs independently of astrocyte regeneration. J Clin Invest 2021; 131:141694. [PMID: 33645550 DOI: 10.1172/jci141694] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Accepted: 01/06/2021] [Indexed: 01/19/2023] Open
Abstract
Approximately 80% of neuromyelitis optica spectrum disorder (NMOSD) patients harbor serum anti-aquaporin-4 autoantibodies targeting astrocytes in the CNS. Crucial for NMOSD lesion initiation is disruption of the blood-brain barrier (BBB), which allows the entrance of Abs and serum complement into the CNS and which is a target for new NMOSD therapies. Astrocytes have important functions in BBB maintenance; however, the influence of their loss and the role of immune cell infiltration on BBB permeability in NMOSD have not yet been investigated. Using an experimental model of targeted NMOSD lesions in rats, we demonstrate that astrocyte destruction coincides with a transient disruption of the BBB and a selective loss of occludin from tight junctions. It is noteworthy that BBB integrity is reestablished before astrocytes repopulate. Rather than persistent astrocyte loss, polymorphonuclear leukocytes (PMNs) are the main mediators of BBB disruption, and their depletion preserves BBB integrity and prevents astrocyte loss. Inhibition of PMN chemoattraction, activation, and proteolytic function reduces lesion size. In summary, our data support a crucial role for PMNs in BBB disruption and NMOSD lesion development, rendering their recruitment and activation promising therapeutic targets.
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Affiliation(s)
| | | | - Michael Haberl
- Institute for Multiple Sclerosis Research and Neuroimmunology, University Medical Center Göttingen, Göttingen, Germany
| | - Marie-Theres Weil
- Electron Microscopy Core Unit, Department of Neurogenetics, Max-Planck-Institute of Experimental Medicine, Göttingen, Germany.,Center Nanoscale Microscopy and Molecular Physiology of the Brain (CNMPB), Göttingen, Germany
| | - Ming Gao
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana, USA
| | - Wiebke Möbius
- Electron Microscopy Core Unit, Department of Neurogenetics, Max-Planck-Institute of Experimental Medicine, Göttingen, Germany.,Center Nanoscale Microscopy and Molecular Physiology of the Brain (CNMPB), Göttingen, Germany
| | - Francesca Odoardi
- Institute for Multiple Sclerosis Research and Neuroimmunology, University Medical Center Göttingen, Göttingen, Germany
| | - Dietmar R Thal
- Department of Imaging and Pathology, KU Leuven, and Department of Pathology, UZ Leuven, Leuven, Belgium.,Laboratory of Neuropathology, Institute of Pathology, Ulm University, Ulm, Germany
| | - Mayland Chang
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana, USA
| | - Ghislain Opdenakker
- Laboratory of Immunobiology, Department of Microbiology and Immunology, Rega Institute for Medical Research, KU Leuven, Leuven, Belgium
| | - Jeffrey L Bennett
- Departments of Neurology and Ophthalmology, Program in Neuroscience, University of Colorado at Anschutz Medical Campus, Aurora, Colorado, USA
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71
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Imafuku K, Kamaguchi M, Natsuga K, Nakamura H, Shimizu H, Iwata H. Zonula occludens-1 demonstrates a unique appearance in buccal mucosa over several layers. Cell Tissue Res 2021; 384:691-702. [PMID: 33635425 DOI: 10.1007/s00441-021-03425-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2019] [Accepted: 01/24/2021] [Indexed: 02/07/2023]
Abstract
Tight junctions (TJs) firmly seal epithelial cells and are key players in the epithelial barrier. TJs consist of several proteins, including those of the transmembrane claudin family and the scaffold zonula occludens (ZO) family. Epithelial tissues are exposed to different conditions: to air in the stratified epithelium of the skin and to liquids in the monolayer of the intestine. The TJs in stratified oral mucosal epithelium have remained insufficiently elucidated in terms of distributions, appearances and barrier functions of TJ proteins in normal buccal mucosa. We investigated these and ZO-1 and claudin-1 were found to be expressed in the top third and in the bottom three quarters of the mucosal epithelium. ZO-1 in the buccal mucosa was found to have an irregular linear appearance. ZO-1 in the buccal mucosa continuously existed in several layers. Electron microscopy revealed the buccal mucosa to have kissing points. In a biotin permeation assay that sought to investigate inside-outside barrier function, the biotin tracer penetrated several ZO-1 layers but did not pass through all the ZO-1 layers. We found that the oral mucosal cell knockdown of TJP1 or CLDN1 resulted in decreases of TER but no significant change in FITC-dextran leakage. Our results suggest that the distribution and appearance of ZO-1 in the buccal mucosa differ from those in the skin. We were unable to prove barrier function in this study but we did show barrier function against small molecules in vivo and against ions in vitro.
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Affiliation(s)
- Keisuke Imafuku
- Department of Dermatology, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Kita-ku, 060-8638, Sapporo, Japan
| | - Mayumi Kamaguchi
- Department of Oral Diagnosis and Medicine, Faculty of Medicine and Graduate School of Dental Medicine, Hokkaido University, Kita 13, Nishi 7, Kita-ku, Sapporo, 060-8586, Japan.,Lübeck Institute of Experimental Dermatology, University of Lübeck, Building B9 Ratzeburger Allee 160, 23562, Lubeck, Germany
| | - Ken Natsuga
- Department of Dermatology, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Kita-ku, 060-8638, Sapporo, Japan
| | - Hideki Nakamura
- Department of Dermatology, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Kita-ku, 060-8638, Sapporo, Japan
| | - Hiroshi Shimizu
- Department of Dermatology, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Kita-ku, 060-8638, Sapporo, Japan
| | - Hiroaki Iwata
- Department of Dermatology, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Kita-ku, 060-8638, Sapporo, Japan.
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72
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Kumar B, Ahmad R, Giannico GA, Zent R, Talmon GA, Harris RC, Clark PE, Lokeshwar V, Dhawan P, Singh AB. Claudin-2 inhibits renal clear cell carcinoma progression by inhibiting YAP-activation. JOURNAL OF EXPERIMENTAL & CLINICAL CANCER RESEARCH : CR 2021; 40:77. [PMID: 33622361 PMCID: PMC7901196 DOI: 10.1186/s13046-021-01870-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/22/2020] [Accepted: 02/08/2021] [Indexed: 12/28/2022]
Abstract
Background Claudin-2 expression is upregulated in multiple cancers and promotes cancer malignancy. Remarkably, the regulation of claudin-2 expression in kidney cell lines contrasts its reported regulation in other organs. However, claudin-2 role in renal clear cell carcinoma (RCC) remains unknown despite its predominant expression in the proximal tubular epithelium (PTE), the site of RCC origin. Methods Publicly available and independent patient databases were examined for claudin-2 association with RCC. The novel protein function was validated in vitro and in vivo by gain or loss of function assays. Mechanistic results were concluded by Mass spectroscopy, immunoprecipitation and mutational studies, and functional evaluations. Results We show that the significant decrease in claudin-2 expression characterized PTE cells and Ex-vivo cultured mouse kidney subjected to dedifferentiation. Inhibition of claudin-2 was enough to induce mesenchymal plasticity and invasive mobility in these models. Further, a progressive loss of claudin-2 expression associated with the RCC progression and poor patient survival. Overexpression of claudin-2 in RCC-derived cancer cells inhibited tumorigenic abilities and xenograft tumor growth. These data supported a novel tumor-suppressive role of claudin-2 in RCC. Mechanistic insights further revealed that claudin-2 associates with YAP-protein and modulates its phosphorylation (S127) and nuclear expression. The tumor suppressive effects of claudin-2 expression were lost upon deletion of its PDZ-binding motif emphasizing the critical role of the PDZ-domain in claudin-2 interaction with YAP in regulating RCC malignancy. Conclusions Our results demonstrate a novel kidney specific tumor suppressive role for claudin-2 protein and further demonstrate that claudin-2 co-operates with the YAP signaling in regulating the RCC malignancy. Supplementary Information The online version contains supplementary material available at 10.1186/s13046-021-01870-5.
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Affiliation(s)
- Balawant Kumar
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, 985870 Nebraska Medical Center, Omaha, NE, 68198-5870, USA
| | - Rizwan Ahmad
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, 985870 Nebraska Medical Center, Omaha, NE, 68198-5870, USA
| | - Giovanna A Giannico
- Department of Pathology, Microbiology and Immunology, Vanderbilt Medical Center, Nashville, TN, USA
| | - Roy Zent
- Department of Medicine, Vanderbilt Medical Center, Nashville, TN, USA
| | - Geoffrey A Talmon
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, NE, 68198, USA
| | - Raymond C Harris
- Department of Medicine, Vanderbilt Medical Center, Nashville, TN, USA
| | | | - Vinata Lokeshwar
- Department of Biochemistry and Molecular Biology, Augusta University, Augusta, GA, USA
| | - Punita Dhawan
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, 985870 Nebraska Medical Center, Omaha, NE, 68198-5870, USA.,Member, Fred and Pamela Buffett Cancer Center, University of Nebraska Medical Center, 985870 Nebraska Medical Center, Omaha, NE, 68198-5870, USA.,VA Nebraska-Western Iowa Health Care System, Omaha, NE, USA
| | - Amar B Singh
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, 985870 Nebraska Medical Center, Omaha, NE, 68198-5870, USA. .,Member, Fred and Pamela Buffett Cancer Center, University of Nebraska Medical Center, 985870 Nebraska Medical Center, Omaha, NE, 68198-5870, USA. .,VA Nebraska-Western Iowa Health Care System, Omaha, NE, USA.
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73
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Saito AC, Higashi T, Fukazawa Y, Otani T, Tauchi M, Higashi AY, Furuse M, Chiba H. Occludin and tricellulin facilitate formation of anastomosing tight-junction strand network to improve barrier function. Mol Biol Cell 2021; 32:722-738. [PMID: 33566640 PMCID: PMC8108510 DOI: 10.1091/mbc.e20-07-0464] [Citation(s) in RCA: 56] [Impact Index Per Article: 18.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Tight junctions (TJs) are composed of a claudin-based anastomosing network of TJ strands at which plasma membranes of adjacent epithelial cells are closely attached to regulate the paracellular permeability. Although the TJ proteins occludin and tricellulin have been known to be incorporated in the TJ strand network, their molecular functions remain unknown. Here, we established tricellulin/occludin-double knockout (dKO) MDCK II cells using a genome editing technique and evaluated the structure and barrier function of these cells. In freeze-fracture replica electron microscopy, the TJ strands of tricellulin/occludin-dKO cells had fewer branches and were less anastomosed compared with the controls. The paracellular permeability of ions and small tracers was increased in the dKO cells. A single KO of tricellulin or occludin had limited effects on the morphology and permeability of TJs. Mathematical simulation using a simplified TJ strand network model predicted that reduced cross-links in TJ strands lead to increased permeability of ions and small macromolecules. Furthermore, overexpression of occludin increased the complexity of TJ strand network and strengthened barrier function. Taken together, our data suggest that tricellulin and occludin mediate the formation and/or stabilization of TJ-strand branching points and contribute to the maintenance of epithelial barrier integrity.
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Affiliation(s)
- Akira C Saito
- Department of Basic Pathology, Fukushima Medical University, Fukushima 960-1295, Japan
| | - Tomohito Higashi
- Department of Basic Pathology, Fukushima Medical University, Fukushima 960-1295, Japan
| | - Yugo Fukazawa
- Division of Brain Structure and Function, Research Center for Child Mental Development, School of Medical Science, University of Fukui, Fukui 910-1193, Japan
| | - Tetsuhisa Otani
- Division of Cell Structure, National Institute for Physiological Sciences, Okazaki, Aichi 444-8787, Japan.,Department of Physiological Sciences, School of Life Science, SOKENDAI (Graduate University for Advanced Studies), Okazaki, Aichi 444-8585, Japan
| | - Masashi Tauchi
- Department of Basic Pathology, Fukushima Medical University, Fukushima 960-1295, Japan
| | - Atsuko Y Higashi
- Department of Basic Pathology, Fukushima Medical University, Fukushima 960-1295, Japan
| | - Mikio Furuse
- Division of Cell Structure, National Institute for Physiological Sciences, Okazaki, Aichi 444-8787, Japan.,Department of Physiological Sciences, School of Life Science, SOKENDAI (Graduate University for Advanced Studies), Okazaki, Aichi 444-8585, Japan
| | - Hideki Chiba
- Department of Basic Pathology, Fukushima Medical University, Fukushima 960-1295, Japan
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74
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Shima A, Matsuoka H, Yamaoka A, Michihara A. Transcription of CLDND1 in human brain endothelial cells is regulated by the myeloid zinc finger 1. Clin Exp Pharmacol Physiol 2021; 48:260-269. [PMID: 33037622 DOI: 10.1111/1440-1681.13416] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2020] [Revised: 09/12/2020] [Accepted: 10/05/2020] [Indexed: 12/01/2022]
Abstract
Increased permeability of endothelial cells lining the blood vessels in the brain leads to vascular oedema and, potentially, to stroke. The tight junctions (TJs), primarily responsible for the regulation of vascular permeability, are multi-protein complexes comprising the claudin family of proteins and occludin. Several studies have reported that downregulation of the claudin domain containing 1 (CLDND1) gene enhances vascular permeability, which consequently increases the risk of stroke. However, the transcriptional regulation of CLDND1 has not been studied extensively. Therefore, this study aimed to identify the transcription factors (TFs) regulating CLDND1 expression. A luciferase reporter assay identified a silencer within the first intron of CLDND1, which was identified as a potential binding site of the myeloid zinc finger 1 (MZF1) through in silico and TFBIND software analyses, and confirmed through a reporter assay using the MZF1 expression vector and chromatin immunoprecipitation (ChIP) assays. Moreover, the transient overexpression of MZF1 significantly increased the mRNA and protein expression levels of CLDND1, conversely, which were suppressed through the siRNA-mediated MZF1 knockdown. Furthermore, the permeability of FITC-dextran was observed to be increased on MZF1 knockdown as compared to that of the siGFP control. Our data revealed the underlying mechanism of the transcriptional regulation of CLDND1 by the MZF1. The findings suggest a potential role of MZF1 in TJ formation, which could be studied further and applied to prevent cerebral haemorrhage.
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Affiliation(s)
- Akiho Shima
- Laboratory of Genomic Function and Pathophysiology, Faculty of Pharmacy and Pharmaceutical Sciences, Fukuyama University, Fukuyama, Japan
| | - Hiroshi Matsuoka
- Laboratory of Genomic Function and Pathophysiology, Faculty of Pharmacy and Pharmaceutical Sciences, Fukuyama University, Fukuyama, Japan
| | - Alice Yamaoka
- Laboratory of Genomic Function and Pathophysiology, Faculty of Pharmacy and Pharmaceutical Sciences, Fukuyama University, Fukuyama, Japan
| | - Akihiro Michihara
- Laboratory of Genomic Function and Pathophysiology, Faculty of Pharmacy and Pharmaceutical Sciences, Fukuyama University, Fukuyama, Japan
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75
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Jia Z, Bao K, Wei P, Yu X, Zhang Y, Wang X, Wang X, Yao L, Li L, Wu P, Yuan W, Wang S, Zheng J, Hua Y, Hong M. EGFR activation-induced decreases in claudin1 promote MUC5AC expression and exacerbate asthma in mice. Mucosal Immunol 2021; 14:125-134. [PMID: 32132671 DOI: 10.1038/s41385-020-0272-z] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2019] [Revised: 02/09/2020] [Accepted: 02/11/2020] [Indexed: 02/04/2023]
Abstract
Claudin1 plays a critical role in maintaining the epithelial barrier, and mucus hypersecretion induced by epidermal growth factor receptor (EGFR) activation is a pivotal pathological feature of asthma. The relationship between claudin1 expression and mucus hypersecretion and EGFR activation is still poorly understood. In this report, we showed that claudin1 expression correlated with asthma stage, in both patients with asthma and in the house dust mite (HDM)-induced mouse asthma model. Claudin1 knockdown induced MUC5AC overexpression both in 16HBE cells and in mouse airways. In addition, claudin1 expression negatively correlated with asthma severity as demonstrated by significantly higher MUC5AC expression, more severe airway inflammation, and increased airway hyperreactivity in mouse lungs with claudin1 knockdown following HDM challenge. EGFR activation reduced claudin1 expression and increased MUC5AC expression, both in vitro and in vivo. Erlotinib alleviated murine allergic airway inflammation, restored claudin1 expression and decreased MUC5AC expression. These results suggest that EGFR activation-induced decreases in claudin1 promote goblet-cell metaplasia, and restoring claudin1 to maintain barrier integrity by EGFR antagonism may provide a novel therapeutic strategy for asthma.
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Affiliation(s)
- Zhirong Jia
- Jiangsu Key Laboratory for Pharmacology and Safety Evaluation of Chinese Materia Medica, School of Pharmacy, Nanjing University of Chinese Medicine, 210046, Nanjing, China.,School of Basic Medicine and Clinical Pharmacy, China Pharmaceutical University, 211198, Nanjing, China
| | - Kaifan Bao
- Jiangsu Key Laboratory for Pharmacology and Safety Evaluation of Chinese Materia Medica, School of Pharmacy, Nanjing University of Chinese Medicine, 210046, Nanjing, China
| | - Pan Wei
- Jiangsu Key Laboratory for Pharmacology and Safety Evaluation of Chinese Materia Medica, School of Pharmacy, Nanjing University of Chinese Medicine, 210046, Nanjing, China
| | - Xuerui Yu
- Jiangsu Key Laboratory for Pharmacology and Safety Evaluation of Chinese Materia Medica, School of Pharmacy, Nanjing University of Chinese Medicine, 210046, Nanjing, China
| | - Yuheng Zhang
- Jiangsu Key Laboratory for Pharmacology and Safety Evaluation of Chinese Materia Medica, School of Pharmacy, Nanjing University of Chinese Medicine, 210046, Nanjing, China
| | - Xiaotong Wang
- Jiangsu Key Laboratory for Pharmacology and Safety Evaluation of Chinese Materia Medica, School of Pharmacy, Nanjing University of Chinese Medicine, 210046, Nanjing, China
| | - Xiaoyu Wang
- Jiangsu Key Laboratory for Pharmacology and Safety Evaluation of Chinese Materia Medica, School of Pharmacy, Nanjing University of Chinese Medicine, 210046, Nanjing, China
| | - Lu Yao
- Jiangsu Key Laboratory for Pharmacology and Safety Evaluation of Chinese Materia Medica, School of Pharmacy, Nanjing University of Chinese Medicine, 210046, Nanjing, China
| | - Lianqu Li
- Jiangsu Key Laboratory for Pharmacology and Safety Evaluation of Chinese Materia Medica, School of Pharmacy, Nanjing University of Chinese Medicine, 210046, Nanjing, China
| | - Peng Wu
- Jiangsu Key Laboratory for Pharmacology and Safety Evaluation of Chinese Materia Medica, School of Pharmacy, Nanjing University of Chinese Medicine, 210046, Nanjing, China
| | - Weiyuan Yuan
- Jiangsu Key Laboratory for Pharmacology and Safety Evaluation of Chinese Materia Medica, School of Pharmacy, Nanjing University of Chinese Medicine, 210046, Nanjing, China
| | - Siqi Wang
- Jiangsu Key Laboratory for Pharmacology and Safety Evaluation of Chinese Materia Medica, School of Pharmacy, Nanjing University of Chinese Medicine, 210046, Nanjing, China
| | - Jie Zheng
- Jiangsu Key Laboratory for Pharmacology and Safety Evaluation of Chinese Materia Medica, School of Pharmacy, Nanjing University of Chinese Medicine, 210046, Nanjing, China.,School of Medicine and Life Science, Nanjing University of Chinese Medicine, 210046, Nanjing, China
| | - Yongqing Hua
- Jiangsu Key Laboratory for Pharmacology and Safety Evaluation of Chinese Materia Medica, School of Pharmacy, Nanjing University of Chinese Medicine, 210046, Nanjing, China
| | - Min Hong
- Jiangsu Key Laboratory for Pharmacology and Safety Evaluation of Chinese Materia Medica, School of Pharmacy, Nanjing University of Chinese Medicine, 210046, Nanjing, China.
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Li F, Egea PF, Vecchio AJ, Asial I, Gupta M, Paulino J, Bajaj R, Dickinson MS, Ferguson-Miller S, Monk BC, Stroud RM. Highlighting membrane protein structure and function: A celebration of the Protein Data Bank. J Biol Chem 2021; 296:100557. [PMID: 33744283 PMCID: PMC8102919 DOI: 10.1016/j.jbc.2021.100557] [Citation(s) in RCA: 39] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2020] [Revised: 02/10/2021] [Accepted: 03/16/2021] [Indexed: 12/13/2022] Open
Abstract
Biological membranes define the boundaries of cells and compartmentalize the chemical and physical processes required for life. Many biological processes are carried out by proteins embedded in or associated with such membranes. Determination of membrane protein (MP) structures at atomic or near-atomic resolution plays a vital role in elucidating their structural and functional impact in biology. This endeavor has determined 1198 unique MP structures as of early 2021. The value of these structures is expanded greatly by deposition of their three-dimensional (3D) coordinates into the Protein Data Bank (PDB) after the first atomic MP structure was elucidated in 1985. Since then, free access to MP structures facilitates broader and deeper understanding of MPs, which provides crucial new insights into their biological functions. Here we highlight the structural and functional biology of representative MPs and landmarks in the evolution of new technologies, with insights into key developments influenced by the PDB in magnifying their impact.
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Affiliation(s)
- Fei Li
- Department of Biochemistry and Biophysics, University of California San Francisco, San Francisco, California, USA; Department of Neurology, University of California San Francisco, San Francisco, California, USA
| | - Pascal F Egea
- Department of Biological Chemistry, School of Medicine, University of California Los Angeles, Los Angeles, California, USA
| | - Alex J Vecchio
- Department of Biochemistry, University of Nebraska-Lincoln, Lincoln, Nebraska, USA
| | | | - Meghna Gupta
- Department of Biochemistry and Biophysics, University of California San Francisco, San Francisco, California, USA
| | - Joana Paulino
- Department of Biochemistry and Biophysics, University of California San Francisco, San Francisco, California, USA
| | - Ruchika Bajaj
- Department of Bioengineering and Therapeutic Sciences, University of California San Francisco, San Francisco, California, USA
| | - Miles Sasha Dickinson
- Department of Biochemistry and Biophysics, University of California San Francisco, San Francisco, California, USA
| | - Shelagh Ferguson-Miller
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan, USA
| | - Brian C Monk
- Sir John Walsh Research Institute and Department of Oral Sciences, University of Otago, North Dunedin, Dunedin, New Zealand
| | - Robert M Stroud
- Department of Biochemistry and Biophysics, University of California San Francisco, San Francisco, California, USA.
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Towards the development of a human in vitro model of the blood-brain barrier for virus-associated acute encephalopathy: assessment of the time- and concentration-dependent effects of TNF-α on paracellular tightness. Exp Brain Res 2020; 239:451-461. [PMID: 33219841 DOI: 10.1007/s00221-020-05985-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2020] [Accepted: 11/09/2020] [Indexed: 12/30/2022]
Abstract
The pathogenesis of virus-associated acute encephalopathy (VAE) involves brain edema caused by disruption of the blood-brain barrier (BBB). We aimed to develop an in vitro VAE model using an in vitro BBB model, to evaluate the dynamics of vascular dysfunction caused by tumor necrosis factor (TNF)-α. A co-culture model, consisting of Transwell®-grown human brain microvascular endothelial cells and pericytes, was treated with serially diluted TNF-α. Transendothelial electrical resistance (TER) was measured using cellZscope®. A permeability assay, using fluorescein isothiocyanate-conjugated sodium or dextran, was performed. Changes in claudin-5 localization and expression after TNF-α treatment were observed using immunofluorescence staining and western blot analysis. The TER decreased and permeability increased after TNF-α treatment; recovery time was dependent on TNF-α concentration. Claudin-5 was delocalized after TNF-α treatment and recovered in a TNF-α concentration-dependent manner. The expression of claudin-5 decreased 24 h after the TNF-α treatment and completely recovered 48 h after TNF-α treatment. Claudin-5 delocalization was likely associated with vascular hyperpermeability. To conclude, we evaluated vascular endothelial cell permeability and injury in VAE using an in vitro BBB model treated with TNF-α. This system can be useful for developing novel therapeutic strategies for VAE and designing treatments that target vascular permeability.
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78
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Zou H, Shan C, Ma L, Liu J, Yang N, Zhao J. Polarity and epithelial-mesenchymal transition of retinal pigment epithelial cells in proliferative vitreoretinopathy. PeerJ 2020; 8:e10136. [PMID: 33150072 PMCID: PMC7583629 DOI: 10.7717/peerj.10136] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2020] [Accepted: 09/18/2020] [Indexed: 12/11/2022] Open
Abstract
Under physiological conditions, retinal pigment epithelium (RPE) is a cellular monolayer composed of mitotically quiescent cells. Tight junctions and adherens junctions maintain the polarity of RPE cells, and are required for cellular functions. In proliferative vitreoretinopathy (PVR), upon retinal tear, RPE cells lose cell-cell contact, undergo epithelial-mesenchymal transition (EMT), and ultimately transform into myofibroblasts, leading to the formation of fibrocellular membranes on both surfaces of the detached retina and on the posterior hyaloids, which causes tractional retinal detachment. In PVR, RPE cells are crucial contributors, and multiple signaling pathways, including the SMAD-dependent pathway, Rho pathway, MAPK pathways, Jagged/Notch pathway, and the Wnt/β-catenin pathway are activated. These pathways mediate the EMT of RPE cells, which play a key role in the pathogenesis of PVR. This review summarizes the current body of knowledge on the polarized phenotype of RPE, the role of cell-cell contact, and the molecular mechanisms underlying the RPE EMT in PVR, emphasizing key insights into potential approaches to prevent PVR.
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Affiliation(s)
- Hui Zou
- Eye Center, The Second Hospital of Jilin University, Changchun, China
| | - Chenli Shan
- Eye Center, The Second Hospital of Jilin University, Changchun, China
| | - Linlin Ma
- Eye Center, The Second Hospital of Jilin University, Changchun, China
| | - Jia Liu
- Eye Center, The Second Hospital of Jilin University, Changchun, China
| | - Ning Yang
- Eye Center, The Second Hospital of Jilin University, Changchun, China
| | - Jinsong Zhao
- Eye Center, The Second Hospital of Jilin University, Changchun, China
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79
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Zhu M, Lu J, Shen J, Fei L, Chen D. A 22-amino-acid peptide regulates tight junctions through occludin and cell apoptosis. PeerJ 2020; 8:e10147. [PMID: 33194394 PMCID: PMC7646304 DOI: 10.7717/peerj.10147] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Accepted: 09/21/2020] [Indexed: 12/18/2022] Open
Abstract
Occludin is a structural protein of tight junctions (TJ) in the blood–testis barrier (BTB). A 22-amino-acid peptide (22AA) in the second extracellular loop can reversibly regulate TJ, but its regulatory mechanism is unknown. In this study, a 22AA-induced TJ destruction animal model was constructed to investigate the effect of 22AA on Sertoli cells (SCs) and spermatid counts and cell apoptosis at different time points using a multiplex immunofluorescence technique. The effect of 22AA on the location and distribution of occludin was analyzed via dual confocal fluorescence microscope. Western blotting was used to analyze dynamic changes in occludin expression. Real-time RT-PCR was used to analyze miR-122-5p expression changes. Sperm density counts and mating methods were used to analyze the effect of 22AA on fertility in mice. The results showed that 22AA promoted SC and spermatid apoptosis, downregulated occludin, upregulated miR-122-5p, and decreased sperm density and litter size before 27 days (27D). After 27D, the expression of occludin increased again, miR-122-5p expression decreased again, both sperm density and litter size returned to normal, apoptosis stopped, and spermatogenesis began to recover. Therefore, it can be concluded that 22AA can destroy TJ by downregulating occludin and inducing cell apoptosis. After 27D, TJ and spermatogenesis functions return to normal.
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Affiliation(s)
- Maoying Zhu
- College of Biological and Food Engineering, Fuyang Normal University, Fuyang, Anhui, China
| | - Juan Lu
- College of Biological and Food Engineering, Fuyang Normal University, Fuyang, Anhui, China
| | - Jianyun Shen
- College of Biological and Food Engineering, Fuyang Normal University, Fuyang, Anhui, China
| | - Lumin Fei
- College of Biological and Food Engineering, Fuyang Normal University, Fuyang, Anhui, China
| | - Deyu Chen
- College of Medicine, Fuyang Normal University, Fuyang, Anhui, China
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80
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Rudraraju M, Narayanan SP, Somanath PR. Regulation of blood-retinal barrier cell-junctions in diabetic retinopathy. Pharmacol Res 2020; 161:105115. [PMID: 32750417 PMCID: PMC7755666 DOI: 10.1016/j.phrs.2020.105115] [Citation(s) in RCA: 82] [Impact Index Per Article: 20.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Revised: 07/22/2020] [Accepted: 07/27/2020] [Indexed: 12/15/2022]
Abstract
Loss of the blood-retinal barrier (BRB) integrity and subsequent damage to the neurovascular unit in the retina are the underlying reasons for diabetic retinopathy (DR). Damage to BRB eventually leads to severe visual impairment in the absence of prompt intervention. Diabetic macular edema and proliferative DR are the advanced stages of the disease where BRB integrity is altered. Primary mechanisms contributing to BRB dysfunction include loss of cell-cell barrier junctions, vascular endothelial growth factor, advanced glycation end products-induced damage, and oxidative stress. Although much is known about the involvement of adherens and tight-junction proteins in the regulation of vascular permeability in various diseases, there is a significant gap in our knowledge on the junctional proteins expressed in the BRB and how BRB function is modulated in the diabetic retina. In this review article, we present our current understanding of the molecular composition of BRB, the changes in the BRB junctional protein turnover in DR, and how BRB functional modulation affects vascular permeability and macular edema in the diabetic retina.
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Affiliation(s)
- Madhuri Rudraraju
- Clinical and Experimental Therapeutics, College of Pharmacy, University of Georgia and Charlie Norwood VA Medical Center, Augusta, GA 30912, United States; James and Jean Culver Vision Discovery Institute, Augusta University, Augusta, GA 30912, United States
| | - S Priya Narayanan
- Clinical and Experimental Therapeutics, College of Pharmacy, University of Georgia and Charlie Norwood VA Medical Center, Augusta, GA 30912, United States; Vascular Biology Center, Augusta University, Augusta, GA 30912, United States; James and Jean Culver Vision Discovery Institute, Augusta University, Augusta, GA 30912, United States
| | - Payaningal R Somanath
- Clinical and Experimental Therapeutics, College of Pharmacy, University of Georgia and Charlie Norwood VA Medical Center, Augusta, GA 30912, United States; Vascular Biology Center, Augusta University, Augusta, GA 30912, United States; Department of Medicine, Augusta University, Augusta, GA 30912, United States.
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81
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Rouaud F, Sluysmans S, Flinois A, Shah J, Vasileva E, Citi S. Scaffolding proteins of vertebrate apical junctions: structure, functions and biophysics. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2020; 1862:183399. [DOI: 10.1016/j.bbamem.2020.183399] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/13/2020] [Revised: 06/05/2020] [Accepted: 06/11/2020] [Indexed: 12/11/2022]
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82
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Otani T, Furuse M. Tight Junction Structure and Function Revisited. Trends Cell Biol 2020; 30:805-817. [PMID: 32891490 DOI: 10.1016/j.tcb.2020.08.004] [Citation(s) in RCA: 302] [Impact Index Per Article: 75.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2020] [Revised: 08/03/2020] [Accepted: 08/06/2020] [Indexed: 12/14/2022]
Abstract
Tight junctions (TJs) are intercellular junctions critical for building the epithelial barrier and maintaining epithelial polarity. The claudin family of membrane proteins play central roles in TJ structure and function. However, recent findings have uncovered claudin-independent aspects of TJ structure and function, and additional players including junctional adhesion molecules (JAMs), membrane lipids, phase separation of the zonula occludens (ZO) family of scaffolding proteins, and mechanical force have been shown to play important roles in TJ structure and function. In this review, we discuss how these new findings have the potential to transform our understanding of TJ structure and function, and how the intricate network of TJ proteins and membrane lipids dynamically interact to drive TJ assembly.
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Affiliation(s)
- Tetsuhisa Otani
- Division of Cell Structure, National Institute for Physiological Sciences, Okazaki, Aichi 444-8787, Japan; Department of Physiological Sciences, SOKENDAI (The Graduate University for Advanced Studies), Okazaki, Aichi 444-8787, Japan.
| | - Mikio Furuse
- Division of Cell Structure, National Institute for Physiological Sciences, Okazaki, Aichi 444-8787, Japan; Department of Physiological Sciences, SOKENDAI (The Graduate University for Advanced Studies), Okazaki, Aichi 444-8787, Japan
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83
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Chopyk DM, Grakoui A. Contribution of the Intestinal Microbiome and Gut Barrier to Hepatic Disorders. Gastroenterology 2020; 159:849-863. [PMID: 32569766 PMCID: PMC7502510 DOI: 10.1053/j.gastro.2020.04.077] [Citation(s) in RCA: 218] [Impact Index Per Article: 54.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/06/2020] [Revised: 04/16/2020] [Accepted: 04/29/2020] [Indexed: 02/07/2023]
Abstract
Intestinal barrier dysfunction and dysbiosis contribute to development of diseases in liver and other organs. Physical, immunologic, and microbiologic (bacterial, fungal, archaeal, viral, and protozoal) features of the intestine separate its nearly 100 trillion microbes from the rest of the human body. Failure of any aspect of this barrier can result in translocation of microbes into the blood and sustained inflammatory response that promote liver injury, fibrosis, cirrhosis, and oncogenic transformation. Alterations in intestinal microbial populations or their functions can also affect health. We review the mechanisms that regulate intestinal permeability and how changes in the intestinal microbiome contribute to development of acute and chronic liver diseases. We discuss individual components of the intestinal barrier and how these are disrupted during development of different liver diseases. Learning more about these processes will increase our understanding of the interactions among the liver, intestine, and its flora.
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Affiliation(s)
- Daniel M. Chopyk
- Emory Vaccine Center, Division of Microbiology and Immunology, Yerkes National Primate Research Center, Emory University School of Medicine, Atlanta, GA
| | - Arash Grakoui
- Emory Vaccine Center, Division of Microbiology and Immunology, Yerkes National Primate Research Center, Emory University School of Medicine, Atlanta, Georgia; Division of Infectious Diseases, Department of Medicine, Emory University School of Medicine, Atlanta, Georgia.
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84
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Lee PH, Hong J, Jang AS. N-acetylcysteine decreases airway inflammation and responsiveness in asthma by modulating claudin 18 expression. Korean J Intern Med 2020; 35:1229-1237. [PMID: 32098455 PMCID: PMC7487305 DOI: 10.3904/kjim.2019.105] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/25/2019] [Accepted: 07/15/2019] [Indexed: 12/18/2022] Open
Abstract
BACKGROUND/AIMS N-acetylcysteine (NAC) affects signaling pathways involved in apoptosis, angiogenesis, cell growth and arrest, redox-regulated gene expression, and the inflammatory response. However, it is not known how the signal mechanism for tight junctional protein claudin (CLDN) 18 is regulated in asthma patients. METHODS To investigate the effects of NAC on CLDN18 expression in a mouse model of asthma, and to assess plasma levels of CLDN18 in asthma patients. A murine model of asthma induced by ovalbumin (OVA) was established using wild-type BALB/c female mice, and the levels of CLDNs, phosphorylated-pyruvate dehydrogenase kinase 1 (p-PDK1), and protein kinase B (Akt) pathway proteins following NAC treatment were examined by Western blotting and immunohistochemistry. In addition, the plasma levels of CLDN18 were evaluated in asthmatic patients and control subjects. RESULTS NAC diminished OVA-induced airway hyper-responsiveness and inflammation. Levels of CLDN18 protein were higher in lung tissue from OVA mice than tissue from control mice, and were increased by treatment with NAC or dexamethasone. Treatment with NAC or dexamethasone decreased the OVA-induced increase in interleukin-1α protein levels. Although treatment with NAC increased OVA-induced p-PDK1 protein levels, it decreased phosphorylated Akt (pAkt)/Akt levels. Soluble CLDN18 levels were lower in patients with asthma than in controls and were correlated with the percentage of neutrophils, forced expiratory volume in 1 second (FEV1)/forced vital capacity % (FVC%) and FEV1%. CONCLUSION CLDN18 plays a role in the pathogenesis of asthma and NAC diminishes airway inflammation and responsiveness by modulating CLDN18 expression.
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Affiliation(s)
- Pureun-Haneul Lee
- Department of Internal Medicine, Soonchunhyang University Bucheon Hospital, Bucheon, Korea
| | - Jisu Hong
- Department of Internal Medicine, Soonchunhyang University Bucheon Hospital, Bucheon, Korea
| | - An-Soo Jang
- Department of Internal Medicine, Soonchunhyang University Bucheon Hospital, Bucheon, Korea
- Correspondence to An-Soo Jang, M.D. Division of Allergy and Respiratory Medicine, Department of Internal Medicine, Soonchunhyang University Bucheon Hospital, 170 Jomaru-ro, Wonmi-gu, Bucheon 14584, Korea Tel: +82-32-621-5143 Fax: +82-32-621-6950 E-mail:
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85
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A Weak Link with Actin Organizes Tight Junctions to Control Epithelial Permeability. Dev Cell 2020; 54:792-804.e7. [PMID: 32841596 DOI: 10.1016/j.devcel.2020.07.022] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2019] [Revised: 05/23/2020] [Accepted: 07/29/2020] [Indexed: 01/13/2023]
Abstract
In vertebrates, epithelial permeability is regulated by the tight junction (TJ) formed by specialized adhesive membrane proteins, adaptor proteins, and the actin cytoskeleton. Despite the TJ's critical physiological role, a molecular-level understanding of how TJ assembly sets the permeability of epithelial tissue is lacking. Here, we identify a 28-amino-acid sequence in the TJ adaptor protein ZO-1, which is responsible for actin binding, and show that this interaction is essential for TJ permeability. In contrast to the strong interactions at the adherens junction, we find that the affinity between ZO-1 and actin is surprisingly weak, and we propose a model based on kinetic trapping to explain how affinity could affect TJ assembly. Finally, by tuning the affinity of ZO-1 to actin, we demonstrate that epithelial monolayers can be engineered with a spectrum of permeabilities, which points to a promising target for treating transport disorders and improving drug delivery.
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86
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Anwer S, Szaszi K. Immunofluorescent Staining of Claudin-2 in Cultured Kidney Tubular Cells. Bio Protoc 2020; 10:e3678. [PMID: 33659349 DOI: 10.21769/bioprotoc.3678] [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: 01/22/2020] [Revised: 03/31/2020] [Accepted: 05/20/2020] [Indexed: 11/02/2022] Open
Abstract
Members of the claudin family of tight junction proteins regulate paracellular permeability and modulate cell signaling. During junction remodeling, these proteins are selectively inserted into or retrieved from the tight junctions, but the control and coordination of these processes remain incompletely understood. Visualization of claudins allows the assessment of changes in their localization and abundance. We use the described protocol to stain claudin-2, but it can also be adapted to stain any tight junction protein. We found that using methanol for fixing allows the best preservation of claudin-2 both at the membrane and in cytoplasmic vesicles. Staining is done using a claudin-2 specific primary and a fluorescently labelled secondary antibody, along with DAPI to label nuclei. The samples are then imaged using confocal microscopy, and a z-stack is obtained allowing visualization of both junctional and intracellular claudin-2. Total claudin-2 signal can be quantified after 3D reconstruction of the images using the Imaris software.
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Affiliation(s)
- Shaista Anwer
- Keenan Research Centre for Biomedical Science of the St. Michael's Hospital, Toronto, Canada
| | - Katalin Szaszi
- Keenan Research Centre for Biomedical Science of the St. Michael's Hospital, Toronto, Canada.,Dept. of Surgery, University of Toronto, ON, Canada
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87
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Cytoskeletal Organization and Cell Polarity in the Pathogenesis of Crohn’s Disease. Clin Rev Allergy Immunol 2020; 60:164-174. [DOI: 10.1007/s12016-020-08795-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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88
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Jin Y, Blikslager AT. The Regulation of Intestinal Mucosal Barrier by Myosin Light Chain Kinase/Rho Kinases. Int J Mol Sci 2020; 21:ijms21103550. [PMID: 32443411 PMCID: PMC7278945 DOI: 10.3390/ijms21103550] [Citation(s) in RCA: 63] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Revised: 05/15/2020] [Accepted: 05/16/2020] [Indexed: 12/19/2022] Open
Abstract
The intestinal epithelial apical junctional complex, which includes tight and adherens junctions, contributes to the intestinal barrier function via their role in regulating paracellular permeability. Myosin light chain II (MLC-2), has been shown to be a critical regulatory protein in altering paracellular permeability during gastrointestinal disorders. Previous studies have demonstrated that phosphorylation of MLC-2 is a biochemical marker for perijunctional actomyosin ring contraction, which increases paracellular permeability by regulating the apical junctional complex. The phosphorylation of MLC-2 is dominantly regulated by myosin light chain kinase- (MLCK-) and Rho-associated coiled-coil containing protein kinase- (ROCK-) mediated pathways. In this review, we aim to summarize the current state of knowledge regarding the role of MLCK- and ROCK-mediated pathways in the regulation of the intestinal barrier during normal homeostasis and digestive diseases. Additionally, we will also suggest potential therapeutic targeting of MLCK- and ROCK-associated pathways in gastrointestinal disorders that compromise the intestinal barrier.
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Affiliation(s)
- Younggeon Jin
- Department of Animal and Avian Sciences, College of Agriculture and Natural Resources, University of Maryland, College Park, MD 20742, USA;
| | - Anthony T. Blikslager
- Department of Clinical Sciences, Comparative Medicine Institute, College of Veterinary Medicine, North Carolina State University, Raleigh, NC 27607, USA
- Correspondence:
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89
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Lynn KS, Peterson RJ, Koval M. Ruffles and spikes: Control of tight junction morphology and permeability by claudins. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2020; 1862:183339. [PMID: 32389670 DOI: 10.1016/j.bbamem.2020.183339] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2020] [Revised: 04/24/2020] [Accepted: 05/01/2020] [Indexed: 02/06/2023]
Abstract
Epithelial barrier function is regulated by a family of transmembrane proteins known as claudins. Functional tight junctions are formed when claudins interact with other transmembrane proteins, cytosolic scaffold proteins and the actin cytoskeleton. The predominant scaffold protein, zonula occludens-1 (ZO-1), directly binds to most claudin C-terminal domains, crosslinking them to the actin cytoskeleton. When imaged by immunofluorescence microscopy, tight junctions most frequently are linear structures that form between tricellular junctions. However, tight junctions also adapt non-linear architectures exhibiting either a ruffled or spiked morphology, which both are responses to changes in claudin engagement of actin filaments. Other terms for ruffled tight junctions include wavy, tortuous, undulating, serpentine or zig-zag junctions. Ruffling is under the control of hypoxia induced factor (HIF) and integrin-mediated signaling, as well as direct mechanical stimulation. Tight junction ruffling is specifically enhanced by claudin-2, antagonized by claudin-1 and requires claudin binding to ZO-1. Tight junction spikes are sites of active vesicle budding and fusion that appear as perpendicular projections oriented towards the nucleus. Spikes share molecular features with focal adherens junctions and tubulobulbar complexes found in Sertoli cells. Lung epithelial cells under stress form spikes due to an increase in claudin-5 expression that directly disrupts claudin-18/ZO-1 interactions. Together this suggests that claudins are not simply passive cargoes controlled by scaffold proteins. We propose a model where claudins specifically influence tight junction scaffold proteins to control interactions with the cytoskeleton as a mechanism that regulates tight junction assembly and function.
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Affiliation(s)
- K Sabrina Lynn
- Division of Pulmonary, Allergy Critical Care and Sleep Medicine, Department of Medicine, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Raven J Peterson
- Division of Pulmonary, Allergy Critical Care and Sleep Medicine, Department of Medicine, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Michael Koval
- Division of Pulmonary, Allergy Critical Care and Sleep Medicine, Department of Medicine, Emory University School of Medicine, Atlanta, GA 30322, USA; Department of Cell Biology, Emory University School of Medicine, Atlanta, GA 30322, USA.
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90
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Post-translational modifications of tight junction transmembrane proteins and their direct effect on barrier function. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2020; 1862:183330. [PMID: 32376223 DOI: 10.1016/j.bbamem.2020.183330] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Revised: 04/21/2020] [Accepted: 04/27/2020] [Indexed: 12/24/2022]
Abstract
Post-translational modifications (PTMs) such as phosphorylation, ubiquitination or glycosylation are processes affecting the conformation, stability, localization and function of proteins. There is clear evidence that PTMs can act upon tight junction (TJ) proteins, thus modulating epithelial barrier function. Compared to transcriptional or translational regulation, PTMs are rapid and more dynamic processes so in the context of barrier maintenance they might be essential for coping with changing environmental or external impacts. The aim of this review is to extract literature deciphering PTMs in TJ proteins directly contributing to epithelial barrier changes in permeability to ions and macromolecules. It is not intended to cover the entire scope of PTMs in TJ proteins and should rather be understood as a digest of TJ protein modifications directly resulting in the tightening or opening of the epithelial barrier.
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91
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Shi Y, Li R, Yang J, Li X. No tight junctions in tight junction protein-1 expressing HeLa and fibroblast cells. INTERNATIONAL JOURNAL OF PHYSIOLOGY, PATHOPHYSIOLOGY AND PHARMACOLOGY 2020; 12:70-78. [PMID: 32419902 PMCID: PMC7218737] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 01/06/2020] [Accepted: 04/08/2020] [Indexed: 06/11/2023]
Abstract
Tight junctions are important structures that form the barrier of cells and tissues, and they play key roles in maintaining homeostasis of our body. The backbone of the tight junction proteins are claudins, which composed more than twenty members. The tight junction protein 1 (TJP1), also called ZO-1 (Zonula Occludens-1), is one of the tight junction related proteins, and it is widely used in literature to label tight junctions. Here we showed that TJP1 (ZO-1) is highly expressed in cancerous HeLa cells, fibroblast cells, HUVEC as well as MDCK cells, while claudin-1 is highly expressed in HUVEC and MDCK cells, but not expressed in HeLa and fibroblast cells. We aimed to investigate whether tight junction is present in HeLa and fibroblast cells. We used transepithelial/transendothelial electrical resistance (TEER) to measure tight junction dynamics in these cells. The results showed that there is no TEERs in HeLa and fibroblast cells, while there is relatively high TEER in HUVEC and MDCK cells. Importantly, the TEER in MDCK cells is dramatically reduced after knockdown of TJP1 (ZO-1). These results suggest that TJP1 (ZO-1) cannot be used as a marker of tight junctions in a variety of cells, while TJP1 (ZO-1) may play an important role in regulation of tight junctions in MDCK cells.
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Affiliation(s)
- Yumeng Shi
- Eye Institute, Eye and Ear, Nose, and Throat Hospital of Fudan University83 Fenyang Road, Shanghai 200031, People’s Republic of China
| | - Rongqiang Li
- Department of Urology, Weihaiwei HospitalWeihai, Shandong, China
| | - Jin Yang
- Eye Institute, Eye and Ear, Nose, and Throat Hospital of Fudan University83 Fenyang Road, Shanghai 200031, People’s Republic of China
| | - Xinbo Li
- Ophthalmology, Casey Eye Institute, Oregon Health & Science UniversityPortland, Oregon, USA
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92
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Mailly L, Baumert TF. Hepatitis C virus infection and tight junction proteins: The ties that bind. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2020; 1862:183296. [PMID: 32268133 DOI: 10.1016/j.bbamem.2020.183296] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/13/2020] [Revised: 03/25/2020] [Accepted: 03/28/2020] [Indexed: 02/07/2023]
Abstract
The hepatitis C virus (HCV) is a major cause of liver diseases ranging from liver inflammation to advanced liver diseases like cirrhosis and hepatocellular carcinoma (HCC). HCV infection is restricted to the liver, and more specifically to hepatocytes, which represent around 80% of liver cells. The mechanism of HCV entry in human hepatocytes has been extensively investigated since the discovery of the virus 30 years ago. The entry mechanism is a multi-step process relying on several host factors including heparan sulfate proteoglycan (HSPG), low density lipoprotein receptor (LDLR), tetraspanin CD81, Scavenger Receptor class B type I (SR-BI), Epidermal Growth Factor Receptor (EGFR) and Niemann-Pick C1-like 1 (NPC1L1). Moreover, in order to establish a persistent infection, HCV entry is dependent on the presence of tight junction (TJ) proteins Claudin-1 (CLDN1) and Occludin (OCLN). In the liver, tight junction proteins play a role in architecture and homeostasis including sealing the apical pole of adjacent cells to form bile canaliculi and separating the basolateral domain drained by sinusoidal blood flow. In this review, we will highlight the role of liver tight junction proteins in HCV infection, and we will discuss the potential targeted therapeutic approaches to improve virus eradication.
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Affiliation(s)
- Laurent Mailly
- Université de Strasbourg, INSERM, UMR-S1110, Institut de Recherche sur les Maladies Virales et Hépatiques, F-67000 Strasbourg, France.
| | - Thomas F Baumert
- Université de Strasbourg, INSERM, UMR-S1110, Institut de Recherche sur les Maladies Virales et Hépatiques, F-67000 Strasbourg, France; Pôle Hépato-digestif, Hôpitaux Universitaires de Strasbourg, F-67000 Strasbourg, France; Institut Universitaire de France, F-75231 Paris, France.
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93
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Sassi A, Wang Y, Chassot A, Komarynets O, Roth I, Olivier V, Crambert G, Dizin E, Boscardin E, Hummler E, Feraille E. Interaction between Epithelial Sodium Channel γ-Subunit and Claudin-8 Modulates Paracellular Sodium Permeability in Renal Collecting Duct. J Am Soc Nephrol 2020; 31:1009-1023. [PMID: 32245797 DOI: 10.1681/asn.2019080790] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2019] [Accepted: 02/15/2020] [Indexed: 12/25/2022] Open
Abstract
BACKGROUND Water and solute transport across epithelia can occur via the transcellular or paracellular pathways. Tight junctions play a key role in mediating paracellular ion reabsorption in the kidney. In the renal collecting duct, which is a typical absorptive tight epithelium, coordination between transcellular sodium reabsorption and paracellular permeability may prevent the backflow of reabsorbed sodium to the tubular lumen along a steep electrochemical gradient. METHODS To investigate whether transcellular sodium transport controls tight-junction composition and paracellular permeability via modulating expression of the transmembrane protein claudin-8, we used cultured mouse cortical collecting duct cells to see how overexpression or silencing of epithelial sodium channel (ENaC) subunits and claudin-8 affect paracellular permeability. We also used conditional kidney tubule-specific knockout mice lacking ENaC subunits to assess the ENaC's effect on claudin-8 expression. RESULTS Overexpression or silencing of the ENaC γ-subunit was associated with parallel and specific changes in claudin-8 abundance. Increased claudin-8 abundance was associated with a reduction in paracellular permeability to sodium, whereas decreased claudin-8 abundance was associated with the opposite effect. Claudin-8 overexpression and silencing reproduced these functional effects on paracellular ion permeability. Conditional kidney tubule-specific ENaC γ-subunit knockout mice displayed decreased claudin-8 expression, confirming the cell culture experiments' findings. Importantly, ENaC β-subunit or α-subunit silencing or kidney tubule-specific β-ENaC or α-ENaC knockout mice did not alter claudin-8 abundance. CONCLUSIONS Our data reveal the specific coupling between ENaC γ-subunit and claudin-8 expression. This coupling may play an important role in preventing the backflow of reabsorbed solutes and water to the tubular lumen, as well as in coupling paracellular and transcellular sodium permeability.
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Affiliation(s)
- Ali Sassi
- Department of Cellular Physiology and Metabolism, University of Geneva, University Medical Center, Geneva, Switzerland.,National Center of Competence in Research Kidney Control of Homeostasis (Kidney.CH), Zurich, Switzerland
| | - Yubao Wang
- Department of Cellular Physiology and Metabolism, University of Geneva, University Medical Center, Geneva, Switzerland.,National Center of Competence in Research Kidney Control of Homeostasis (Kidney.CH), Zurich, Switzerland
| | - Alexandra Chassot
- Department of Cellular Physiology and Metabolism, University of Geneva, University Medical Center, Geneva, Switzerland.,National Center of Competence in Research Kidney Control of Homeostasis (Kidney.CH), Zurich, Switzerland
| | - Olga Komarynets
- Department of Cellular Physiology and Metabolism, University of Geneva, University Medical Center, Geneva, Switzerland
| | - Isabelle Roth
- Department of Cellular Physiology and Metabolism, University of Geneva, University Medical Center, Geneva, Switzerland
| | - Valérie Olivier
- Department of Cellular Physiology and Metabolism, University of Geneva, University Medical Center, Geneva, Switzerland.,National Center of Competence in Research Kidney Control of Homeostasis (Kidney.CH), Zurich, Switzerland
| | - Gilles Crambert
- Sorbonne University, Unité Mixte de Recherche (UMR) S1138, Cordeliers Research Center, Paris, France
| | - Eva Dizin
- Department of Cellular Physiology and Metabolism, University of Geneva, University Medical Center, Geneva, Switzerland.,National Center of Competence in Research Kidney Control of Homeostasis (Kidney.CH), Zurich, Switzerland
| | - Emilie Boscardin
- National Center of Competence in Research Kidney Control of Homeostasis (Kidney.CH), Zurich, Switzerland.,Department of Biomedical Sciences, University of Lausanne, Lausanne, Switzerland
| | - Edith Hummler
- National Center of Competence in Research Kidney Control of Homeostasis (Kidney.CH), Zurich, Switzerland.,Department of Biomedical Sciences, University of Lausanne, Lausanne, Switzerland
| | - Eric Feraille
- Department of Cellular Physiology and Metabolism, University of Geneva, University Medical Center, Geneva, Switzerland .,National Center of Competence in Research Kidney Control of Homeostasis (Kidney.CH), Zurich, Switzerland
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94
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Assembly of Tight Junction Strands: Claudin-10b and Claudin-3 Form Homo-Tetrameric Building Blocks that Polymerise in a Channel-Independent Manner. J Mol Biol 2020; 432:2405-2427. [DOI: 10.1016/j.jmb.2020.02.034] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2019] [Revised: 02/12/2020] [Accepted: 02/28/2020] [Indexed: 02/03/2023]
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95
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Kolosov D, Bui P, Wilkie MP, Kelly SP. Claudins of sea lamprey (Petromyzon marinus) - organ-specific expression and transcriptional responses to water of varying ion content. JOURNAL OF FISH BIOLOGY 2020; 96:768-781. [PMID: 32017083 DOI: 10.1111/jfb.14274] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/23/2019] [Accepted: 01/27/2020] [Indexed: 06/10/2023]
Abstract
The role of lamprey epithelium tight junctions (TJs) in the regulation of salt and water balance is poorly understood. This study reported on claudin (Cldn) TJ protein transcripts of pre-metamorphic larval and post-metamorphic juvenile sea lamprey (Petromyzon marinus) and the transcriptional response of genes encoding Cldns to changed environmental ion levels. Transcripts encoding Cldn-3b, -4, -5, -10, -14, -18 and -19 were identified, and mRNA expression profiles revealed the organ-specific presence of cldn-5 and -14, broad expression of cldn-3b, -4, -10, -18 and -19 and spatial differences in the mRNA abundance of cldn-4, -3b and -14 along the ammocoete intestine. Expression profiles were qualitatively similar in ammocoetes and juvenile fishes. Transcript abundance of genes encoding Cldns in osmoregulatory organs (gill, kidney, intestine and skin) was subsequently investigated after exposure of ammocoetes to ion-poor water (IPW) and juveniles to hyperosmotic conditions [60% sea water (SW)]. IPW-acclimated ammocoetes increased mRNA abundance of nearly all cldns in the gill. Simultaneously, cldn-10 abundance increased in the skin, whereas cldn-4, -14 and -18 decreased in the kidney. Ammocoete cldn mRNA abundance in the intestine was altered in a region-specific manner. In contrast, cldn transcript abundance was mostly downregulated in osmoregulatory organs of juvenile fish acclimated to SW - cldn-3b, -10 and -19 in the gill; cldn-3b, -4, -10 and -19 in the skin; cldn-3b in the kidney; and cldn-3b and -14 in the intestine. Data support the idea that Cldn TJ proteins play an important role in the osmoregulatory physiology of pre- and post-metamorphic sea lamprey and that Cldn participation can occur across organs, in an organ-specific manner, as well as differ spatially within organs, which contributes to the regulation of salt and water balance in these fishes.
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Affiliation(s)
- Dennis Kolosov
- Department of Biology, York University, Toronto, Ontario, Canada
- Department of Biology, McMaster University, Hamilton, Ontario, Canada
| | - Phuong Bui
- Department of Biology, York University, Toronto, Ontario, Canada
- Department of Biology, University of Toronto Mississauga, Mississauga, Ontario, Canada
| | - Mike P Wilkie
- Department of Biology, Wilfrid Laurier University, Waterloo, Ontario, Canada
| | - Scott P Kelly
- Department of Biology, York University, Toronto, Ontario, Canada
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96
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Abstract
Epithelial cells form highly organized polarized sheets with characteristic cell morphologies and tissue architecture. Cell–cell adhesion and intercellular communication are prerequisites of such cohesive sheets of cells, and cell connectivity is mediated through several junctional assemblies, namely desmosomes, adherens, tight and gap junctions. These cell–cell junctions form signalling hubs that not only mediate cell–cell adhesion but impact on multiple aspects of cell behaviour, helping to coordinate epithelial cell shape, polarity and function. This review will focus on the tight and adherens junctions, constituents of the apical junctional complex, and aims to provide a comprehensive overview of the complex signalling that underlies junction assembly, integrity and plasticity.
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Affiliation(s)
- Alexandra D Rusu
- School of Life Sciences, University of Nottingham, Nottingham NG7 2UH, UK
| | - Marios Georgiou
- School of Life Sciences, University of Nottingham, Nottingham NG7 2UH, UK
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97
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Molecular organization and function of vertebrate septate-like junctions. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2020; 1862:183211. [PMID: 32032590 DOI: 10.1016/j.bbamem.2020.183211] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Revised: 01/22/2020] [Accepted: 01/26/2020] [Indexed: 12/21/2022]
Abstract
Septate-like junctions display characteristic ladder-like ultrastructure reminiscent of the invertebrate epithelial septate junctions and are present at the paranodes of myelinated axons. The paranodal junctions where the myelin loops attach to the axon at the borders of the node of Ranvier provide both a paracellular barrier to ion diffusion and a lateral fence along the axonal membrane. The septate-like junctions constrain the proper distribution of nodal Na+ channels and juxtaparanodal K+ channels, which are required for the safe propagation of the nerve influx and rapid saltatory conduction. The paranodal cell adhesion molecules have been identified as target antigens in peripheral demyelinating autoimmune diseases and the pathogenic mechanisms described. This review aims at presenting the recent knowledge on the molecular and structural organization of septate-like junctions, their formation and stabilization during development, and how they are involved in demyelinating diseases.
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98
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Contributions of Myosin Light Chain Kinase to Regulation of Epithelial Paracellular Permeability and Mucosal Homeostasis. Int J Mol Sci 2020; 21:ijms21030993. [PMID: 32028590 PMCID: PMC7037368 DOI: 10.3390/ijms21030993] [Citation(s) in RCA: 75] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2020] [Revised: 01/30/2020] [Accepted: 01/30/2020] [Indexed: 12/20/2022] Open
Abstract
Intestinal barrier function is required for the maintenance of mucosal homeostasis. Barrier dysfunction is thought to promote progression of both intestinal and systemic diseases. In many cases, this barrier loss reflects increased permeability of the paracellular tight junction as a consequence of myosin light chain kinase (MLCK) activation and myosin II regulatory light chain (MLC) phosphorylation. Although some details about MLCK activation remain to be defined, it is clear that this triggers perijunctional actomyosin ring (PAMR) contraction that leads to molecular reorganization of tight junction structure and composition, including occludin endocytosis. In disease states, this process can be triggered by pro-inflammatory cytokines including tumor necrosis factor-α (TNF), interleukin-1β (IL-1β), and several related molecules. Of these, TNF has been studied in the greatest detail and is known to activate long MLCK transcription, expression, enzymatic activity, and recruitment to the PAMR. Unfortunately, toxicities associated with inhibition of MLCK expression or enzymatic activity make these unsuitable as therapeutic targets. Recent work has, however, identified a small molecule that prevents MLCK1 recruitment to the PAMR without inhibiting enzymatic function. This small molecule, termed Divertin, restores barrier function after TNF-induced barrier loss and prevents disease progression in experimental chronic inflammatory bowel disease.
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99
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Miyazono S, Otani T, Ogata K, Kitagawa N, Iida H, Inai Y, Matsuura T, Inai T. The reduced susceptibility of mouse keratinocytes to retinoic acid may be involved in the keratinization of oral and esophageal mucosal epithelium. Histochem Cell Biol 2020; 153:225-237. [PMID: 32006103 DOI: 10.1007/s00418-020-01845-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/14/2020] [Indexed: 10/24/2022]
Abstract
Keratinocytes take up serum-derived retinol (vitamin A) and metabolize it to all-trans-retinoic acid (atRA), which binds to the nuclear retinoic acid receptor (RAR). We previously reported that serum-affected keratinocyte differentiation and function; namely, it inhibited keratinization, decreased loricrin (LOR) and claudin (CLDN) 1 expression, increased keratin (K) 4 and CLDN4 levels, and reduced paracellular permeability in three-dimensional (3D) cultures of mouse keratinocytes (COCA). Contrarily, RAR inhibition reversed these changes. Here, we aimed to examine whether atRA exerted the same effects as serum, and whether it was involved in the differential oral mucosa keratinization among animal species. Porcine oral mucosal keratinocytes, which form non-keratinized epithelium in vivo, established keratinized epithelium in 3D cultures. Both mouse and porcine sera induced non-keratinized epithelium at 0.1% in COCA 3D cultures. Although atRA caused the same changes as serum, its effective concentration differed. atRA inhibited keratinization at 0.1 nM and 1 nM in porcine or human keratinocytes and COCA, respectively. Furthermore, atRA upregulated CLDN7 in the cytoplasm but not in cell-cell contacts. These atRA-induced changes were reverted by RAR inhibition. The results indicate that serum-induced changes are probably due to the effect of serum-derived atRA, and that mouse keratinocytes require higher atRA concentrations to suppress keratinization than porcine and human keratinocytes. We propose that the lower susceptibility of mouse keratinocytes to atRA, rather than a lower retinol concentration, is a possible reason for the keratinization of mouse oral mucosal epithelium.
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Affiliation(s)
- Shoji Miyazono
- Department of Oral Rehabilitation, Fukuoka Dental College, 2-15-1 Tamura, Sawara-ku, Fukuoka, 814-0193, Japan
| | - Takahito Otani
- Department of Morphological Biology, Fukuoka Dental College, 2-15-1 Tamura, Sawara-ku, Fukuoka, 814-0193, Japan
| | - Kayoko Ogata
- Department of Morphological Biology, Fukuoka Dental College, 2-15-1 Tamura, Sawara-ku, Fukuoka, 814-0193, Japan
| | - Norio Kitagawa
- Department of Morphological Biology, Fukuoka Dental College, 2-15-1 Tamura, Sawara-ku, Fukuoka, 814-0193, Japan
| | - Hiroshi Iida
- Laboratory of Zoology, Graduate School of Agriculture, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka, 819-0395, Japan
| | - Yuko Inai
- Division of General Dentistry, Kyushu University Hospital, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan
| | - Takashi Matsuura
- Department of Oral Rehabilitation, Fukuoka Dental College, 2-15-1 Tamura, Sawara-ku, Fukuoka, 814-0193, Japan
| | - Tetsuichiro Inai
- Department of Morphological Biology, Fukuoka Dental College, 2-15-1 Tamura, Sawara-ku, Fukuoka, 814-0193, Japan.
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100
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Zhang YX, Jiang ZY, Han SL, Li LY, Qiao F, Zhang ML, Du ZY. Inhibition of intestinal lipases alleviates the adverse effects caused by high-fat diet in Nile tilapia. FISH PHYSIOLOGY AND BIOCHEMISTRY 2020; 46:111-123. [PMID: 31520202 DOI: 10.1007/s10695-019-00701-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/29/2019] [Accepted: 09/02/2019] [Indexed: 06/10/2023]
Abstract
Intestinal lipases are fat-digesting enzymes, which play vital roles in lipid absorption in the intestine. To study the regulation of intestinal lipase activity in systemic lipid metabolism in fish, especially in the metabolic diseases caused by high-fat diet (HFD) feeding, we inhibited intestinal lipases in Nile tilapia to investigate the physiological consequences. In the present study, Nile tilapia were firstly fed with HFD (12% fat) for 6 weeks to establish a fatty fish model. Afterwards, Orlistat as a potent intestinal lipase inhibitor was added into the HFD for the following 5-week feeding trial, with two dietary doses (Orlistat16 group, 16 mg/kg body weight; Orlistat32 group, 32 mg/kg body weight). After the trial, both doses of Orlistat treatment significantly reduced intestinal lipase activity, fat absorption, hepatic lipid accumulation, and gene expression of lipogenesis, whereas increased gene expression of lipid catabolism. Moreover, intestinal lipase inhibition increased immune enzyme activities, antioxidant capacity, and gene expression of anti-inflammatory cytokines, whereas lowered gene expression of pro-inflammatory cytokines. Besides, Orlistat could also improve the structure of the intestine and increase expression of intestinal tight-coupling protein. Taken together, intestinal lipase inhibition alleviated the adverse effects caused by HFD in Nile tilapia. Thus, intestinal lipases played key roles in absorbing dietary lipid and could be a promising target in regulating systemic lipid metabolism in fish.
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Affiliation(s)
- Yu-Xue Zhang
- Laboratory of Aquaculture Nutrition and Environmental Health (LANEH), School of Life Sciences, East China Normal University, Shanghai, 200241, People's Republic of China
| | - Zhe-Yue Jiang
- Laboratory of Aquaculture Nutrition and Environmental Health (LANEH), School of Life Sciences, East China Normal University, Shanghai, 200241, People's Republic of China
| | - Si-Lan Han
- Laboratory of Aquaculture Nutrition and Environmental Health (LANEH), School of Life Sciences, East China Normal University, Shanghai, 200241, People's Republic of China
| | - Ling-Yu Li
- Laboratory of Aquaculture Nutrition and Environmental Health (LANEH), School of Life Sciences, East China Normal University, Shanghai, 200241, People's Republic of China
| | - Fang Qiao
- Laboratory of Aquaculture Nutrition and Environmental Health (LANEH), School of Life Sciences, East China Normal University, Shanghai, 200241, People's Republic of China
| | - Mei-Ling Zhang
- Laboratory of Aquaculture Nutrition and Environmental Health (LANEH), School of Life Sciences, East China Normal University, Shanghai, 200241, People's Republic of China
| | - Zhen-Yu Du
- Laboratory of Aquaculture Nutrition and Environmental Health (LANEH), School of Life Sciences, East China Normal University, Shanghai, 200241, People's Republic of China.
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