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Zheng X, Ren B, Gao Y. Tight junction proteins related to blood-brain barrier and their regulatory signaling pathways in ischemic stroke. Biomed Pharmacother 2023; 165:115272. [PMID: 37544283 DOI: 10.1016/j.biopha.2023.115272] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2023] [Revised: 07/29/2023] [Accepted: 07/31/2023] [Indexed: 08/08/2023] Open
Abstract
Tight junctions (TJs) are crucial for intercellular connections. The abnormal expression of proteins related to TJs can result in TJ destruction, structural damage, and endothelial and epithelial cell dysfunction. These factors are associated with the occurrence and progression of several diseases. Studies have shown that blood-brain barrier (BBB) damage and dysfunction are the prominent pathological features of stroke. TJs are directly associated with the BBB integrity. In this article, we first discuss the structure and function of BBB TJ-related proteins before focusing on the crucial events that cause TJ dysfunction and BBB damage, as well as the regulatory mechanisms that affect the qualitative and quantitative expression of TJ proteins during ischemic stroke. Multiple regulatory mechanisms, including phosphorylation, matrix metalloproteinases (MMPs), and microRNAs, regulate TJ-related proteins and affect BBB permeability. Some signaling pathways and mechanisms have been demonstrated to have dual functions. Hopefully, our understanding of the regulation of BBB TJs in ischemic stroke will be applied to the development of targeted medications and therapeutic therapies.
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Affiliation(s)
- Xiangyi Zheng
- Dongzhimen Hospital, Beijing University of Chinese Medicine, Beijing, China
| | - Beida Ren
- Dongzhimen Hospital, Beijing University of Chinese Medicine, Beijing, China; Institute for Brain Disorders, Beijing University of Chinese Medicine, Beijing, China.
| | - Ying Gao
- Dongzhimen Hospital, Beijing University of Chinese Medicine, Beijing, China; Institute for Brain Disorders, Beijing University of Chinese Medicine, Beijing, China.
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2
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He T, Jin Z, Hu W, Xia X, Li D, Yao W, Li G, Zhou X, Song G. Tetrahydrocurcumin (THC) enhanced the clearance of Cryptococcus deneoformans during infection in vivo. Antonie Van Leeuwenhoek 2023; 116:565-576. [PMID: 37186068 DOI: 10.1007/s10482-023-01830-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2023] [Accepted: 04/07/2023] [Indexed: 05/17/2023]
Abstract
Cryptococcal species often cause lung infections and are the main cause of fungal meningitis. Claudin-4 appears to be a major structural component that maintains a tight alveolar barrier and prevents fluid and electrolyte leakage into the alveolar space. We aimed to determine whether S7-tetrahydrocurcumin (THC) could clearance of C. deneoformans and regulate claudin-4 expression during C. deneoformans infection. We investigated the effect of THC on C. deneoformans infection and its possible mechanism in vivo. Transmission electron microscopy was used to observe the ultrastructure of the lung tissue and the invasion of Cryptococcus. To clarify the effect of THC, we examined claudin-4, c-Jun, and Smad2 expression. We also measured claudin-4 expression in pulmonary specimens from clinical patients. THC reduced cryptococcal cell invasion in the lungs, improved alveolar exudation, and reduced inflammation. Pretreatment with THC suppressed c-Jun and Smad2 expression, resulting in significantly increased claudin-4 levels. In contrast, the expression of claudin-4 in clinical specimens from patients with cryptococcal infection was higher than that in normal specimens. THC enhanced the clearance of C. deneoformans during infection in vivo. We investigated the expression of claudin-4 and the possible mechanism of THC against C. deneoformans infection.
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Affiliation(s)
- Tianli He
- Department of Radiotherapy, Changxing People's Hospital, No. 66, Taihu Road, Changxing, Huzhou, 313100, Zhejiang, China
| | - Zhiran Jin
- Department of Surgery, Changxing People's Hospital, No. 66, Taihu Road, Changxing, Huzhou, 313100, Zhejiang, China
| | - Wei Hu
- Department of Radiotherapy, Changxing People's Hospital, No. 66, Taihu Road, Changxing, Huzhou, 313100, Zhejiang, China
| | - Xiaoxue Xia
- Department of Infectious Diseases Department of Respiratory, Changxing People's Hospital, No. 66, Taihu Road, Changxing, Huzhou , 313100, Zhejiang, China
| | - Donghui Li
- Department of Neurology, Changxing People's Hospital, No. 66, Taihu Road, Changxing, Huzhou, 313100, Zhejiang, China
| | - Weiyun Yao
- Department of Surgery, Changxing People's Hospital, No. 66, Taihu Road, Changxing, Huzhou, 313100, Zhejiang, China
| | - Guangnan Li
- Department of Respiratory Medicine, Changxing County Hospital of Traditional Chinese Medicine, Huzhou, 313100, Zhejiang, China
- Department of Respiratory Medicine, Changxing People's Hospital, No. 66, Taihu Road, Changxing, Huzhou, 313100, Zhejiang, China
| | - Xuefeng Zhou
- Department of Respiratory Medicine, Changxing People's Hospital, No. 66, Taihu Road, Changxing, Huzhou, 313100, Zhejiang, China
| | - Guoqiang Song
- Department of Respiratory Medicine, Changxing County Hospital of Traditional Chinese Medicine, Huzhou, 313100, Zhejiang, China.
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3
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Liu J, Dean DA. Gene Therapy for Acute Respiratory Distress Syndrome. Front Physiol 2022; 12:786255. [PMID: 35111077 PMCID: PMC8801611 DOI: 10.3389/fphys.2021.786255] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Accepted: 11/22/2021] [Indexed: 11/13/2022] Open
Abstract
Acute respiratory distress syndrome (ARDS) is a devastating clinical syndrome that leads to acute respiratory failure and accounts for over 70,000 deaths per year in the United States alone, even prior to the COVID-19 pandemic. While its molecular details have been teased apart and its pathophysiology largely established over the past 30 years, relatively few pharmacological advances in treatment have been made based on this knowledge. Indeed, mortality remains very close to what it was 30 years ago. As an alternative to traditional pharmacological approaches, gene therapy offers a highly controlled and targeted strategy to treat the disease at the molecular level. Although there is no single gene or combination of genes responsible for ARDS, there are a number of genes that can be targeted for upregulation or downregulation that could alleviate many of the symptoms and address the underlying mechanisms of this syndrome. This review will focus on the pathophysiology of ARDS and how gene therapy has been used for prevention and treatment. Strategies for gene delivery to the lung, such as barriers encountered during gene transfer, specific classes of genes that have been targeted, and the outcomes of these approaches on ARDS pathogenesis and resolution will be discussed.
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Affiliation(s)
- Jing Liu
- Department of Pediatrics, University of Rochester, Rochester, NY, United States
- Department of Pharmacology and Physiology, University of Rochester, Rochester, NY, United States
| | - David A. Dean
- Department of Pediatrics, University of Rochester, Rochester, NY, United States
- Department of Pharmacology and Physiology, University of Rochester, Rochester, NY, United States
- *Correspondence: David A. Dean,
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4
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Uddin MA, Akhter MS, Kubra KT, Barabutis N. Induction of the NEK family of kinases in the lungs of mice subjected to cecal ligation and puncture model of sepsis. Tissue Barriers 2021; 9:1929787. [PMID: 34151722 DOI: 10.1080/21688370.2021.1929787] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Endothelial barrier dysfunction (EBD) is the hallmark of Acute Respiratory Distress Syndrome (ARDS), a potentially lethal respiratory disorder associated with the COVID-19 - related deaths. Herein, we employed a cecal ligation and puncture (CLP) murine model of sepsis, to evaluate the effects of sepsis-induced EBD in the expression of the never in mitosis A (NIMA)-related kinases (NEKs). Members of that family of kinases regulate the activity and expression of the tumor suppressor P53, previously shown to modulate the actin cytoskeleton remodeling. Our results introduce the induction of NEK2, NEK3, NEK4, NEK7, and NEK9 in a CLP model of sepsis. Hence, we suggest that NEKs are involved in inflammatory processes and are holding the potential to serve as novel therapeutic targets for pathologies related to EBD, including ARDS and sepsis. Further studies will delineate the underlying molecular events and their interrelations with P53.
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Affiliation(s)
- Mohammad A Uddin
- School of Basic Pharmaceutical and Toxicological Sciences, College of Pharmacy, University of Louisiana Monroe, Monroe, Louisiana USA
| | - Mohammad S Akhter
- School of Basic Pharmaceutical and Toxicological Sciences, College of Pharmacy, University of Louisiana Monroe, Monroe, Louisiana USA
| | - Khadeja-Tul Kubra
- School of Basic Pharmaceutical and Toxicological Sciences, College of Pharmacy, University of Louisiana Monroe, Monroe, Louisiana USA
| | - Nektarios Barabutis
- School of Basic Pharmaceutical and Toxicological Sciences, College of Pharmacy, University of Louisiana Monroe, Monroe, Louisiana USA
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Kojima T, Shindo Y, Konno T, Kodera Y, Arai W, Miyakawa M, Ohwada K, Tanaka H, Tsujiwaki M, Sakuma Y, Kikuchi S, Ohkuni T, Takano K, Watanabe A, Kohno T. Dysfunction of epithelial permeability barrier induced by HMGB1 in 2.5D cultures of human epithelial cells. Tissue Barriers 2021; 10:1972760. [PMID: 34538217 DOI: 10.1080/21688370.2021.1972760] [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] [Indexed: 10/20/2022] Open
Abstract
Airway and intestinal epithelial permeability barriers are crucial in epithelial homeostasis. High mobility group box 1 (HMGB1), increased by various stimuli, is involved in the induction of airway inflammation, as well as the pathogenesis of inflammatory bowel disease. HMGB1 enhances epithelial hyperpermeability. Two-and-a-half dimensional (2.5D) culture assays are experimentally convenient and induce cells to form a more physiological tissue architecture than 2D culture assays for molecular transfer mechanism analysis. In 2.5D culture, treatment with HMGB1 induced permeability of FITC-dextran into the lumen formed by human lung, nasal and intestinal epithelial cells. The tricellular tight junction molecule angulin-1/LSR is responsible for the epithelial permeability barrier at tricellular contacts and contributes to various human airway and intestinal inflammatory diseases. In this review, we indicate the mechanisms including angulin-1/LSR and multiple signaling in dysfunction of the epithelial permeability barrier induced by HMGB1 in 2.5D culture of human airway and intestinal epithelial cells.
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Affiliation(s)
- Takashi Kojima
- Department of Cell Science, Research Institute for Frontier Medicine, Sapporo Medical University School of Medicine, Sapporo, Japan
| | - Yuma Shindo
- Department of Cell Science, Research Institute for Frontier Medicine, Sapporo Medical University School of Medicine, Sapporo, Japan.,Department of Thoracic Surgery, Sapporo Medical University School of Medicine, Sapporo, Japan
| | - Takumi Konno
- Department of Cell Science, Research Institute for Frontier Medicine, Sapporo Medical University School of Medicine, Sapporo, Japan
| | - Yuki Kodera
- Department of Cell Science, Research Institute for Frontier Medicine, Sapporo Medical University School of Medicine, Sapporo, Japan.,Department of Respiratory Medicine and Allergology, Sapporo Medical University School of Medicine, Sapporo, Japan
| | - Wataru Arai
- Department of Cell Science, Research Institute for Frontier Medicine, Sapporo Medical University School of Medicine, Sapporo, Japan.,Department of Thoracic Surgery, Sapporo Medical University School of Medicine, Sapporo, Japan
| | - Maki Miyakawa
- Department of Cell Science, Research Institute for Frontier Medicine, Sapporo Medical University School of Medicine, Sapporo, Japan.,IBD Hospital, Sapporo, Japan
| | - Kizuku Ohwada
- Department of Cell Science, Research Institute for Frontier Medicine, Sapporo Medical University School of Medicine, Sapporo, Japan.,Department of Otolaryngology, Sapporo Medical University School of Medicine, Sapporo, Japan
| | | | - Mitsuhiro Tsujiwaki
- Department of Pathology, Sapporo Medical University School of Medicine, Sapporo, Japan
| | - Yuji Sakuma
- Department of Molecular Medicine, Research Institute for Frontier Medicine, Sapporo Medical University School of Medicine, Sapporo, Japan
| | - Shin Kikuchi
- Department of Anatomy, Sapporo Medical University School of Medicine, Sapporo, Japan
| | - Tsuyoshi Ohkuni
- Department of Otolaryngology, Sapporo Medical University School of Medicine, Sapporo, Japan
| | - Kenichi Takano
- Department of Otolaryngology, Sapporo Medical University School of Medicine, Sapporo, Japan
| | - Atsushi Watanabe
- Department of Thoracic Surgery, Sapporo Medical University School of Medicine, Sapporo, Japan
| | - Takayuki Kohno
- Department of Cell Science, Research Institute for Frontier Medicine, Sapporo Medical University School of Medicine, Sapporo, Japan
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6
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Toll-Like Receptor-Mediated Cardiac Injury during Experimental Sepsis. Mediators Inflamm 2020; 2020:6051983. [PMID: 32410859 PMCID: PMC7199613 DOI: 10.1155/2020/6051983] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2019] [Accepted: 12/20/2019] [Indexed: 12/19/2022] Open
Abstract
Sepsis is associated with global cardiac dysfunction and with high mortality rate. The development of septic cardiomyopathy is due to complex interactions of damage-associated molecular patters, cytokines, and complement activation products. The aim of this study was to define the effects of sepsis on cardiac structure, gap junction, and tight junction (TJ) proteins. Sepsis was induced by cecal ligation and puncture in male C57BL/6 mice. After a period of 24 h, the expression of cardiac structure, gap junction, and TJ proteins was determined. Murine HL-1 cells were stimulated with LPS, and mRNA expression of cardiac structure and gap junction proteins, intracellular reactive oxygen species, and troponin I release was analyzed. Furthermore, pyrogenic receptor subtype 7 (P2X7) expression and troponin I release of human cardiomyocytes (iPS) were determined after LPS exposure. In vivo, protein expression of connexin43 and α-actinin was decreased after the onset of polymicrobial sepsis, whereas in HL-1 cells, mRNA expression of connexin43, α-actinin, and desmin was increased in the presence of LPS. Expression of TJ proteins was not affected in vivo during sepsis. Although the presence of LPS and nigericin resulted in a significant troponin I release from HL-1 cells. Sepsis affected cardiac structure and gap junction proteins in mice, potentially contributing to compromised cardiac function.
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7
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Kurian N, Cohen TS, Öberg L, De Zan E, Skogberg G, Vollmer S, Baturcam E, Svanberg P, Bonn B, Smith PD, Vaarala O, Cunoosamy DM. Dual Role For A MEK Inhibitor As A Modulator Of Inflammation And Host Defense Mechanisms With Potential Therapeutic Application In COPD. Int J Chron Obstruct Pulmon Dis 2019; 14:2611-2624. [PMID: 32063702 PMCID: PMC6885002 DOI: 10.2147/copd.s211619] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Accepted: 09/23/2019] [Indexed: 12/28/2022] Open
Abstract
Background Unlike p38 mitogen-activated protein Kinases (MAPK) that has been extensively studied in the context of lung-associated pathologies in COPD, the role of the dual-specificity mitogen-activated protein kinase kinase (MEK1/2) or its downstream signaling molecule extracellular signal-regulated kinases 1/2 (ERK1/2) in COPD is poorly understood. Objectives The aim of this study was to address whether MEK1/2 pathway activation is linked to COPD and that targeting this pathway can improve lung inflammation through decreased immune-mediated inflammatory responses without compromising bacterial clearance. Methods Association of MEK1/2 pathway activation to COPD was investigated by immunohistochemistry using lung tissue biopsies from COPD and healthy individuals and through analysis of sputum gene expression data from COPD patients. The anti-inflammatory effect of MEK1/2 inhibition was assessed on cytokine release from lipopolysaccharide-stimulated alveolar macrophages. The effect of MEK1/2 inhibition on bacterial clearance was assessed using Staphylococcus aureus killing assays with RAW 264.7 macrophage cell line and human neutrophils. Results We report here MEK1/2 pathway activation demonstrated by increased pERK1/2 staining in bronchial epithelium and by the presence of MEK gene activation signature in sputum samples from COPD patients. Inhibition of MEK1/2 resulted in a superior anti-inflammatory effect in human alveolar macrophages in comparison to a p38 inhibitor. Furthermore, MEK1/2 inhibition led to an increase in bacterial killing in human neutrophils and RAW 264.7 cells that was not observed with the p38 inhibitor. Conclusion Our data demonstrate the activation of MEK1/2 pathway in COPD and highlight a dual function of MEK1/2 inhibition in improving host defense responses whilst also controlling inflammation.
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Affiliation(s)
- Nisha Kurian
- Respiratory Inflammation and Autoimmune (RIA) Precision Medicine Unit, Precision Medicine, Oncology R&D, AstraZeneca, Gothenburg, Sweden
| | | | - Lisa Öberg
- Translational Science and Experimental Medicine, Research and Early Development, RIA, BioPharmaceuticals R&D, AstraZeneca, Gothenburg, Sweden
| | - Erica De Zan
- Translational Science and Experimental Medicine, Research and Early Development, RIA, BioPharmaceuticals R&D, AstraZeneca, Gothenburg, Sweden
| | - Gabriel Skogberg
- Bioscience, Research and Early Development, RIA, BioPharmaceuticals R&D, AstraZeneca, Gothenburg, Sweden
| | - Stefan Vollmer
- Translational Science and Experimental Medicine, Research and Early Development, RIA, BioPharmaceuticals R&D, AstraZeneca, Gothenburg, Sweden
| | - Engin Baturcam
- Translational Science and Experimental Medicine, Research and Early Development, RIA, BioPharmaceuticals R&D, AstraZeneca, Gothenburg, Sweden
| | - Petter Svanberg
- Drug Metabolism and Pharmacokinetics, Research and Early Development, RIA, BioPharmaceuticals R&D, AstraZeneca, Gothenburg, Sweden
| | - Britta Bonn
- Drug Metabolism and Pharmacokinetics, Research and Early Development, RIA, BioPharmaceuticals R&D, AstraZeneca, Gothenburg, Sweden
| | - Paul D Smith
- Bioscience, Oncology R&D, AstraZeneca, Cambridge, UK
| | - Outi Vaarala
- Translational Science and Experimental Medicine, Research and Early Development, RIA, BioPharmaceuticals R&D, AstraZeneca, Gothenburg, Sweden
| | - Danen M Cunoosamy
- Translational Science and Experimental Medicine, Research and Early Development, RIA, BioPharmaceuticals R&D, AstraZeneca, Gothenburg, Sweden
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8
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Yang R, Tan M, Xu J, Zhao X. Investigating the regulatory role of ORMDL3 in airway barrier dysfunction using in vivo and in vitro models. Int J Mol Med 2019; 44:535-548. [PMID: 31173170 PMCID: PMC6605285 DOI: 10.3892/ijmm.2019.4233] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2018] [Accepted: 06/04/2019] [Indexed: 02/06/2023] Open
Abstract
The airway epithelium (AE) is the main protective barrier between the host and external environmental factors causing asthma. Allergens or pathogens induce AE dysfunction, including epithelial permeability alteration, trans‑epithelial electrical resistance (TEER) reduction, upregulation of inflammatory mediators and downregulation of junctional complex molecules. Orosomucoid‑like protein isoform 3 (ORMDL3), a gene closely associated with childhood onset asthma, is involved in airway inflammation and remodeling. It was hypothesized that ORMDL3 plays an important role in regulating AE barrier function. In vivo [chronic asthma induced by ovalbumin‑respiratory syncytial virus (OVA‑RSV)] in mice) and in vitro (human bronchial epithelial cells and 16HBE cells) models were used to assess ORMDL3's role in AE function regulation, evaluating paracellular permeability, TEER and the expression levels of junctional complex molecules. The effects of ORMDL3 on the extracellular signal‑regulated protein kinase (ERK) pathway were determined. In mice with OVA‑RSV induced chronic asthma, ORMDL3 and sphingosine kinase 1 (SPHK1) were upregulated whereas the junction related proteins Claudin‑18 and E‑cadherin were downregulated. Overexpression of ORMDL3 resulted in decreased TEER, downregulation of junctional complex molecules and induced epithelial permeability. In contrast, ORMDL3 inhibition showed the opposite effects. In 16HBE cells, ORMDL3 overexpression induced SPHK1 distribution and activity, while SPHK1 inhibition resulted in increased TEER upon administration of an ORMDL3 agonist or ORMDL3 overexpression. In addition, ERK activation occurred downstream of SPHK1 activation in 16HBE cells. High levels of ORMDL3 result in damaged AE barrier function by inducing the SPHK1/ERK pathway.
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Affiliation(s)
- Ruixue Yang
- Nanjing University of Chinese Medicine, Nanjing, Jiangsu 210023, P.R. China
| | - Min Tan
- Nanjing University of Chinese Medicine, Nanjing, Jiangsu 210023, P.R. China
| | - Jianya Xu
- Jiangsu Key Laboratory of Pediatric Respiratory Disease, Nanjing, Jiangsu 210023, P.R. China
| | - Xia Zhao
- Nanjing University of Chinese Medicine, Nanjing, Jiangsu 210023, P.R. China
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9
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Sim TY, Harith HH, Tham CL, Md Hashim NF, Shaari K, Sulaiman MR, Israf DA. The Protective Effects of a Synthetic Geranyl Acetophenone in a Cellular Model of TNF-α-Induced Pulmonary Epithelial Barrier Dysfunction. Molecules 2018; 23:molecules23061355. [PMID: 29874809 PMCID: PMC6100020 DOI: 10.3390/molecules23061355] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2018] [Revised: 05/19/2018] [Accepted: 05/25/2018] [Indexed: 01/19/2023] Open
Abstract
Alveolar epithelial barrier dysfunction contributes to lung edema and can lead to acute lung injury (ALI). The features include increased epithelial permeability, upregulation of inflammatory mediators and downregulation of junctional complex molecules; these changes are often induced by inflammation. tHGA is an acetophenone analogue with therapeutic potential in asthma. Its therapeutic potential in ALI is presently unknown. Herein, the effects of tHGA on epithelial barrier dysfunction were determined in TNF-α-induced human alveolar epithelial cells. The anti-inflammatory properties of tHGA were assessed by monocyte adhesion assay and analysis of MCP-1 and ICAM-1 expression. The epithelial barrier function was assessed by paracellular permeability and transepithelial electrical resistance (TEER) assays, and analysis of junctional complex molecules expression. To elucidate the mechanism of action, the effects of tHGA on the NF-κB and MAPK pathways were determined. Gene and protein expression were analyzed by RT-PCR and Western blotting or ELISA, respectively. tHGA suppressed leukocyte adhesion to TNF-α-induced epithelium and reduced MCP-1 and ICAM-1 gene expression and secretion. tHGA also increased TEER readings, reduced epithelial permeability and enhanced expression of junctional complex molecules (zona occludens-1, occludin and E-cadherin) in TNF-α-induced cells. Correspondingly, the NF-κB, ERK and p38 MAPK pathways were also inhibited by tHGA. These findings suggest that tHGA is able to preserve alveolar epithelial barrier function in response to acute inflammation, via its anti-inflammatory activity and stabilization of epithelial barrier integrity, mediated by NF-κB, ERK and p38 MAPK signaling.
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Affiliation(s)
- Tee Yee Sim
- Department of Biomedical Science, Faculty of Medicine & Health Sciences, Universiti Putra Malaysia, 43400 Serdang, Selangor, Malaysia.
| | - Hanis Hazeera Harith
- Department of Biomedical Science, Faculty of Medicine & Health Sciences, Universiti Putra Malaysia, 43400 Serdang, Selangor, Malaysia.
| | - Chau Ling Tham
- Department of Biomedical Science, Faculty of Medicine & Health Sciences, Universiti Putra Malaysia, 43400 Serdang, Selangor, Malaysia.
| | - Nur Fariesha Md Hashim
- Department of Biomedical Science, Faculty of Medicine & Health Sciences, Universiti Putra Malaysia, 43400 Serdang, Selangor, Malaysia.
| | - Khozirah Shaari
- Natural Products Laboratory, Institute of Bioscience, Universiti Putra Malaysia, 43400 Serdang, Selangor, Malaysia.
| | - Mohd Roslan Sulaiman
- Department of Biomedical Science, Faculty of Medicine & Health Sciences, Universiti Putra Malaysia, 43400 Serdang, Selangor, Malaysia.
| | - Daud Ahmad Israf
- Department of Biomedical Science, Faculty of Medicine & Health Sciences, Universiti Putra Malaysia, 43400 Serdang, Selangor, Malaysia.
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10
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Kielgast F, Schmidt H, Braubach P, Winkelmann VE, Thompson KE, Frick M, Dietl P, Wittekindt OH. Glucocorticoids Regulate Tight Junction Permeability of Lung Epithelia by Modulating Claudin 8. Am J Respir Cell Mol Biol 2016; 54:707-17. [DOI: 10.1165/rcmb.2015-0071oc] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
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11
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Gonçalves-de-Albuquerque CF, Silva AR, Burth P, Rocco PRM, Castro-Faria MV, Castro-Faria-Neto HC. Possible mechanisms of Pseudomonas aeruginosa-associated lung disease. Int J Med Microbiol 2015; 306:20-8. [PMID: 26652129 DOI: 10.1016/j.ijmm.2015.11.001] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2015] [Revised: 11/11/2015] [Accepted: 11/14/2015] [Indexed: 12/22/2022] Open
Abstract
Pseudomonas aeruginosa is an opportunistic bacterium causing lung injury in immunocompromised patients correlated with high morbidity and mortality. Many bacteria, including P. aeruginosa, use extracellular signals to synchronize group behaviors, a process known as quorum sensing (QS). In the P. aeruginosa complex QS system controls expression of over 300 genes, including many involved in host colonization and disease. P. aeruginosa infection elicits a complex immune response due to a large number of immunogenic factors present in the bacteria or released during infection. Here, we focused on the mechanisms by which P. aeruginosa triggers lung injury and inflammation, debating the possible ways that P. aeruginosa evades the host immune system, which leads to immune suppression and resistance.
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Affiliation(s)
| | - Adriana Ribeiro Silva
- Laboratório de Imunofarmacologia, Instituto Oswaldo Cruz, Fiocruz, Rio de Janeiro, Brazil
| | - Patrícia Burth
- Departamento de Biologia Celular e Molecular, Instituto de Biologia, Universidade Federal Fluminense, Niterói, Brazil
| | - Patricia Rieken Macêdo Rocco
- Laboratório de Investigação Pulmonar, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Mauro Velho Castro-Faria
- Laboratório Integrado de Nefrologia, Departamento de Medicina Interna, Faculdade de Ciências Médicas, Universidade do Estado do Rio de Janeiro, Rio de Janeiro, Brazil
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Song MJ, Davis CI, Lawrence GG, Margulies SS. Local influence of cell viability on stretch-induced permeability of alveolar epithelial cell monolayers. Cell Mol Bioeng 2015; 9:65-72. [PMID: 26958093 DOI: 10.1007/s12195-015-0405-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Ventilator induced lung injury (VILI), often attributed to over-distension of the alveolar epithelial cell layer, can trigger loss of barrier function. Alveolar epithelial cell monolayers can be used as an idealized in vitro model of the pulmonary epithelium, with cell death and tight junction disruption and permeability employed to estimate stretch-induced changes in barrier function. We adapted a method published for vascular endothelial permeability, compare its sensitivity with our previously published method, and determine the relationship between breeches in barrier properties after stretch and regions of cell death After 4-5 days in culture, primary rat alveolar epithelial cells seeded on plasma treated polydimethylsiloxane membrane coated with biotin-labeled fibronectin, or fibronectin alone were stretched in the presence of FITC-tagged streptavidin (biotin-labeled membrane) or BODIPY-ouabain. We found that the FITC-labeling method was a more sensitive indicator of permeability disruption, with significantly larger positively stained areas visible in the presence of stretch and with ATP production inhibitor Antimycin-A. Triple-stained images with Hoescht (nuclei), Ethidium Homodimer (EthD, damaged cell nuclei) and FITC (permeable regions) were used to determine that within permeable regions intact cells were positioned closer to damaged cells than in non-permeable regions. We concluded that local cell death may be an important contributor to barrier integrity.
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Affiliation(s)
- M J Song
- Department of Bioengineering, University of Pennsylvania 210 South 33rd Street, Philadelphia, PA 19104-6321, USA
| | - C I Davis
- Department of Bioengineering, University of Pennsylvania 210 South 33rd Street, Philadelphia, PA 19104-6321, USA
| | - G G Lawrence
- Department of Bioengineering, University of Pennsylvania 210 South 33rd Street, Philadelphia, PA 19104-6321, USA
| | - S S Margulies
- Department of Bioengineering, University of Pennsylvania 210 South 33rd Street, Philadelphia, PA 19104-6321, USA
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Schlingmann B, Molina SA, Koval M. Claudins: Gatekeepers of lung epithelial function. Semin Cell Dev Biol 2015; 42:47-57. [PMID: 25951797 DOI: 10.1016/j.semcdb.2015.04.009] [Citation(s) in RCA: 125] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2015] [Accepted: 04/24/2015] [Indexed: 12/25/2022]
Abstract
The lung must maintain a proper barrier between airspaces and fluid filled tissues in order to maintain lung fluid balance. Central to maintaining lung fluid balance are epithelial cells which create a barrier to water and solutes. The barrier function of these cells is mainly provided by tight junction proteins known as claudins. Epithelial barrier function varies depending on the different needs within the segments of the respiratory tree. In the lower airways, fluid is required to maintain mucociliary clearance, whereas in the terminal alveolar airspaces a thin layer of surfactant enriched fluid lowers surface tension to prevent airspace collapse and is critical for gas exchange. As the epithelial cells within the segments of the respiratory tree differ, the composition of claudins found in these epithelial cells is also different. Among these differences is claudin-18 which is uniquely expressed by the alveolar epithelial cells. Other claudins, notably claudin-4 and claudin-7, are more ubiquitously expressed throughout the respiratory epithelium. Claudin-5 is expressed by both pulmonary epithelial and endothelial cells. Based on in vitro and in vivo model systems and histologic analysis of lungs from human patients, roles for specific claudins in maintaining barrier function and protecting the lung from the effects of acute injury and disease are being identified. One surprising finding is that claudin-18 and claudin-4 control lung cell phenotype and inflammation beyond simply maintaining a selective paracellular permeability barrier. This suggests claudins have more nuanced roles for the control of airway and alveolar physiology in the healthy and diseased lung.
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Affiliation(s)
- Barbara Schlingmann
- Department of Medicine, Division of Pulmonary, Allergy, Critical Care and Sleep Medicine, Emory University School of Medicine, Atlanta, GA 30322, United States; Department of Cell Biology, Emory University School of Medicine, Atlanta, GA 30322, United States
| | - Samuel A Molina
- Department of Medicine, Division of Pulmonary, Allergy, Critical Care and Sleep Medicine, Emory University School of Medicine, Atlanta, GA 30322, United States; Department of Cell Biology, Emory University School of Medicine, Atlanta, GA 30322, United States
| | - Michael Koval
- Department of Medicine, Division of Pulmonary, Allergy, Critical Care and Sleep Medicine, Emory University School of Medicine, Atlanta, GA 30322, United States; Department of Cell Biology, Emory University School of Medicine, Atlanta, GA 30322, United States.
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14
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Ward C, Schlingmann B, Stecenko AA, Guidot DM, Koval M. NF-κB inhibitors impair lung epithelial tight junctions in the absence of inflammation. Tissue Barriers 2015; 3:e982424. [PMID: 25838984 DOI: 10.4161/21688370.2014.982424] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2014] [Accepted: 10/27/2014] [Indexed: 01/11/2023] Open
Abstract
NF-κB (p50/p65) is the best characterized transcription factor known to regulate cell responses to inflammation. However, NF-κB is also constitutively expressed. We used inhibitors of the classical NF-κB signaling pathway to determine whether this transcription factor has a role in regulating alveolar epithelial tight junctions. Primary rat type II alveolar epithelial cells were isolated and cultured on Transwell permeable supports coated with collagen for 5 d to generate a model type I cell monolayer. Treatment of alveolar epithelial monolayers overnight with one of 2 different IκB kinase inhibitors (BAY 11-7082 or BMS-345541) resulted in a dose-dependent decrease in TER at concentrations that did not affect cell viability. In response to BMS-345541 treatment there was an increase in total claudin-4 and claudin-5 along with a decrease in claudin-18, as determined by immunoblot. However, there was little effect on the total amount of cell-associated claudin-7, occludin, junctional adhesion molecule A (JAM-A), zonula occludens (ZO)-1 or ZO-2. Moreover, treatment with BMS-345541 resulted in altered tight junction morphology as assessed by immunofluorescence microscopy. Cells treated with BMS-345541 had an increase in claudin-18 containing projections emanating from tight junctions ("spikes") that were less prominent in control cells. There also were several areas of cell-cell contact which lacked ZO-1 and ZO-2 localization as well as rearrangements to the actin cytoskeleton in response to BMS-345541. Consistent with an anti-inflammatory effect, BMS-345541 antagonized the deleterious effects of lipopolysaccharide (LPS) on alveolar epithelial barrier function. However, BMS-345541 also inhibited the ability of GM-CSF to increase alveolar epithelial TER. These data suggest a dual role for NF-κB in regulating alveolar barrier function and that constitutive NF-κB function is required for the integrity of alveolar epithelial tight junctions.
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Key Words
- ARDS, Acute Respiratory Distress Syndrome
- GM-CSF, Granulocyte Macrophage Colony Stimulating Factor
- IL, interleukin
- IκB, Inhibitor of κB
- JAM-A, junctional adhesion molecule A
- LPS, lipolysaccharide
- NF-κB, nuclear factor kappa-light-chain-enhancer of activated B cells
- PBS, phosphate buffered saline
- TER, transepithelial resistance
- TNF, Tumor Necrosis Factor
- ZO, zonula occludens
- alveolus
- claudin
- lung barrier
- tight junction
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Affiliation(s)
- Christina Ward
- Pulmonary Division; Department of Medicine; Emory University School of Medicine ; Atlanta, GA USA
| | - Barbara Schlingmann
- Pulmonary Division; Department of Medicine; Emory University School of Medicine ; Atlanta, GA USA
| | - Arlene A Stecenko
- Department of Pediatrics; Emory University School of Medicine ; Atlanta, GA USA
| | - David M Guidot
- Pulmonary Division; Department of Medicine; Emory University School of Medicine ; Atlanta, GA USA
| | - Michael Koval
- Pulmonary Division; Department of Medicine; Emory University School of Medicine ; Atlanta, GA USA ; Department of Cell Biology; Emory University School of Medicine ; Atlanta, GA USA
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15
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Junctional adhesion molecule A promotes epithelial tight junction assembly to augment lung barrier function. THE AMERICAN JOURNAL OF PATHOLOGY 2014; 185:372-86. [PMID: 25438062 DOI: 10.1016/j.ajpath.2014.10.010] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/01/2014] [Revised: 09/12/2014] [Accepted: 10/15/2014] [Indexed: 12/14/2022]
Abstract
Epithelial barrier function is maintained by tight junction proteins that control paracellular fluid flux. Among these proteins is junctional adhesion molecule A (JAM-A), an Ig fold transmembrane protein. To assess JAM-A function in the lung, we depleted JAM-A in primary alveolar epithelial cells using shRNA. In cultured cells, loss of JAM-A caused an approximately 30% decrease in transepithelial resistance, decreased expression of the tight junction scaffold protein zonula occludens 1, and disrupted junctional localization of the structural transmembrane protein claudin-18. Consistent with findings in other organs, loss of JAM-A decreased β1 integrin expression and impaired filamentous actin formation. Using a model of mild systemic endoxotemia induced by i.p. injection of lipopolysaccharide, we report that JAM-A(-/-) mice showed increased susceptibility to pulmonary edema. On injury, the enhanced susceptibility of JAM-A(-/-) mice to edema correlated with increased, transient disruption of claudin-18, zonula occludens 1, and zonula occludens 2 localization to lung tight junctions in situ along with a delay in up-regulation of claudin-4. In contrast, wild-type mice showed no change in lung tight junction morphologic features in response to mild systemic endotoxemia. These findings support a key role of JAM-A in promoting tight junction homeostasis and lung barrier function by coordinating interactions among claudins, the tight junction scaffold, and the cytoskeleton.
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16
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Sutherasan Y, D'Antini D, Pelosi P. Advances in ventilator-associated lung injury: prevention is the target. Expert Rev Respir Med 2014; 8:233-48. [PMID: 24601663 DOI: 10.1586/17476348.2014.890519] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Mechanical ventilation (MV) is the main supportive treatment in respiratory failure due to different etiologies. However, MV might aggravate ventilator-associated lung injury (VALI). Four main mechanisms leading to VALI are: 1) increased stress and strain, induced by high tidal volume (VT); 2) increased shear stress, i.e. opening and closing, of previously atelectatic alveolar units; 3) distribution of perfusion and 4) biotrauma. In severe acute respiratory distress syndrome patients, low VT, higher levels of positive end expiratory pressure, long duration prone position and neuromuscular blockade within the first 48 hours are associated to a better outcome. VALI can also occur by using high VT in previously non injured lungs. We believe that prevention is the target to minimize injurious effects of MV. This review aims to describe pathophysiology of VALI, the possible prevention and treatment as well as monitoring MV to minimize VALI.
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Affiliation(s)
- Yuda Sutherasan
- Department of Surgical Sciences and Integrated Diagnostics, University of Genoa, IRCCS San Martino - IST, Genoa, Italy
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17
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Kage H, Flodby P, Gao D, Kim YH, Marconett CN, DeMaio L, Kim KJ, Crandall ED, Borok Z. Claudin 4 knockout mice: normal physiological phenotype with increased susceptibility to lung injury. Am J Physiol Lung Cell Mol Physiol 2014; 307:L524-36. [PMID: 25106430 DOI: 10.1152/ajplung.00077.2014] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Claudins are tight junction proteins that regulate paracellular ion permeability of epithelium and endothelium. Claudin 4 has been reported to function as a paracellular sodium barrier and is one of three major claudins expressed in lung alveolar epithelial cells (AEC). To directly assess the role of claudin 4 in regulation of alveolar epithelial barrier function and fluid homeostasis in vivo, we generated claudin 4 knockout (Cldn4 KO) mice. Unexpectedly, Cldn4 KO mice exhibited normal physiological phenotype although increased permeability to 5-carboxyfluorescein and decreased alveolar fluid clearance were noted. Cldn4 KO AEC monolayers exhibited unchanged ion permeability, higher solute permeability, and lower short-circuit current compared with monolayers from wild-type mice. Claudin 3 and 18 expression was similar between wild-type and Cldn4 KO alveolar epithelial type II cells. In response to either ventilator-induced lung injury or hyperoxia, claudin 4 expression was markedly upregulated in wild-type mice, whereas Cldn4 KO mice showed greater degrees of lung injury. RNA sequencing, in conjunction with differential expression and upstream analysis after ventilator-induced lung injury, suggested Egr1, Tnf, and Il1b as potential mediators of increased lung injury in Cldn4 KO mice. These results demonstrate that claudin 4 has little effect on normal lung physiology but may function to protect against acute lung injury.
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Affiliation(s)
- Hidenori Kage
- Will Rogers Institute Pulmonary Research Center, Division of Pulmonary, Critical Care, and Sleep Medicine, Department of Medicine
| | - Per Flodby
- Will Rogers Institute Pulmonary Research Center, Division of Pulmonary, Critical Care, and Sleep Medicine, Department of Medicine
| | - Danping Gao
- Will Rogers Institute Pulmonary Research Center, Division of Pulmonary, Critical Care, and Sleep Medicine, Department of Medicine
| | - Yong Ho Kim
- Will Rogers Institute Pulmonary Research Center, Division of Pulmonary, Critical Care, and Sleep Medicine, Department of Medicine
| | - Crystal N Marconett
- Departments of Surgery and Biochemistry and Molecular Biology, Norris Comprehensive Cancer Center
| | - Lucas DeMaio
- Will Rogers Institute Pulmonary Research Center, Division of Pulmonary, Critical Care, and Sleep Medicine, Department of Medicine
| | - Kwang-Jin Kim
- Will Rogers Institute Pulmonary Research Center, Division of Pulmonary, Critical Care, and Sleep Medicine, Department of Medicine, Departments of Physiology and Biophysics and Department of Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Southern California; Department of Biomedical Engineering and
| | - Edward D Crandall
- Will Rogers Institute Pulmonary Research Center, Division of Pulmonary, Critical Care, and Sleep Medicine, Department of Medicine, Pathology, Keck School of Medicine, University of Southern California; Mork Family Department of Chemical Engineering and Materials Science, Viterbi School of Engineering, University of Southern California, Los Angeles, California
| | - Zea Borok
- Will Rogers Institute Pulmonary Research Center, Division of Pulmonary, Critical Care, and Sleep Medicine, Department of Medicine, Biochemistry and Molecular Biology, Norris Comprehensive Cancer Center,
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18
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Jin W, Rong L, Liu Y, Song Y, Li Y, Pan J. Increased claudin-3, -4 and -18 levels in bronchoalveolar lavage fluid reflect severity of acute lung injury. Respirology 2013; 18:643-51. [PMID: 23253121 DOI: 10.1111/resp.12034] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2012] [Accepted: 10/09/2012] [Indexed: 11/30/2022]
Affiliation(s)
| | - Linyi Rong
- Department of Pulmonary Medicine; Zhongshan Hospital, Fudan University; Shanghai; China
| | | | | | | | - Jue Pan
- Department of Pulmonary Medicine; Zhongshan Hospital, Fudan University; Shanghai; China
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19
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Cuzić S, Bosnar M, Kramarić MD, Ferencić Z, Marković D, Glojnarić I, Eraković Haber V. Claudin-3 and Clara cell 10 kDa protein as early signals of cigarette smoke-induced epithelial injury along alveolar ducts. Toxicol Pathol 2012; 40:1169-87. [PMID: 22659244 DOI: 10.1177/0192623312448937] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Smoking-associated chronic obstructive pulmonary disease is characterized by inflammation, changes affecting small airways, and development of emphysema. Various short- and long-term models have been introduced to investigate these processes. The aim of the present study was to identify markers of early epithelial injury/adaptation in a short-term animal model of cigarette smoke exposure. Initially, male BALB/c mice were exposed to smoke from one to five cigarettes and lung changes were assessed 4 and 24 hr after smoking cessation. Subsequently, animals were exposed to smoke from five cigarettes for 2 consecutive days and lungs investigated daily until the seventh postexposure day. Lung homogenates cytokines were determined, bronchioloalveolar fluid cells were counted, and lung tissue was analyzed by immunohistochemistry. Exposure to smoke from a single cigarette induced slight pulmonary neutrophilia. Smoke from two cigarettes additionally induced de novo expression of tight junction protein, claudin-3, by alveolar duct (AD) epithelial cells. Further increases in smoke exposure induced epithelial changes in airway progenitor regions. During the recovery period, the severity/frequency of epithelial reactions slowly decreased, coinciding with the switch from acute to a chronic inflammatory reaction. Claudin-3 and Clara cell 10 kDa protein were identified as possible markers of early tobacco smoke-induced epithelial injury along ADs.
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Affiliation(s)
- Snjezana Cuzić
- GlaxoSmithKline Research Centre Zagreb Limited, Zagreb, Croatia.
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20
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Overgaard CE, Mitchell LA, Koval M. Roles for claudins in alveolar epithelial barrier function. Ann N Y Acad Sci 2012; 1257:167-74. [PMID: 22671603 DOI: 10.1111/j.1749-6632.2012.06545.x] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Terminal airspaces of the lung, alveoli, are sites of gas exchange that are sensitive to disrupted fluid balance. The alveolar epithelium is a heterogeneous monolayer of cells interconnected by tight junctions at sites of cell-cell contact. Paracellular permeability depends on claudin (cldn)-family tight junction proteins. Of over a dozen alveolar cldns, cldn-3, cldn-4, and cldn-18 are the most highly expressed; other prominent alveolar claudins include cldn-5 and cldn-7. Cldn-3 is primarily expressed by type II alveolar epithelial cells, whereas cldn-4 and cldn-18 are expressed throughout the alveolar epithelium. Lung diseases associated with pulmonary edema, such as alcoholic lung syndrome and acute lung injury, affect alveolar claudin expression, which is frequently associated with impaired fluid clearance due to increased alveolar leak. However, recent studies have identified a role for increased cldn-4 in protecting alveolar barrier function following injury. Thus, alveolar claudins are dynamically regulated, tailoring lung barrier function to control the air-liquid interface.
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Affiliation(s)
- Christian E Overgaard
- Division of Pulmonary, Allergy and Critical Care Medicine, Department of Medicine, Emory Alcohol and Lung Biology Center, Emory University, Atlanta, Georgia, USA
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21
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Abstract
Lung epithelial cells interconnected by tight junctions provide a barrier to the free diffusion of solutes into airspaces. Transmembrane tight junction proteins known as claudins are essential for epithelial barrier function. Claudins are regulated through interactions with each other that are coordinated with other transmembrane tight junction proteins and cytosolic scaffold proteins. Of the 14 claudins expressed by the alveolar epithelium, claudin-3, claudin-4, and claudin-18 are the most prominent; each confers unique properties to alveolar barrier function. In particular, a protective role for claudin-4 in preventing lung injury has emerged. By contrast, lung diseases that affect claudin expression and impair barrier function, including alcoholic lung syndrome and sepsis, prime the lung for pulmonary edema. Thus, approaches to restore and/or augment lung claudin expression provide potential targets for promoting healthy barrier function.
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Affiliation(s)
- Michael Koval
- Division of Pulmonary, Allergy and Critical Care Medicine, Department of Medicine, Emory University, Atlanta, Georgia 30322, USA.
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22
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Cohen TS, DiPaolo BC, Gray Lawrence G, Margulies SS. Sepsis enhances epithelial permeability with stretch in an actin dependent manner. PLoS One 2012; 7:e38748. [PMID: 22723883 PMCID: PMC3378620 DOI: 10.1371/journal.pone.0038748] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2012] [Accepted: 05/11/2012] [Indexed: 01/11/2023] Open
Abstract
Ventilation of septic patients often leads to the development of edema and impaired gas exchange. We hypothesized that septic alveolar epithelial monolayers would experience stretch-induced barrier dysfunction at a lower magnitude of stretch than healthy alveolar epithelial monolayers. Alveolar epithelial cells were isolated from rats 24 hours after cecal ligation and double puncture (2CLP) or sham surgery. Following a 5-day culture period, monolayers were cyclically stretched for 0, 10, or 60 minutes to a magnitude of 12% or 25% change in surface area (ΔSA). Barrier function, MAPk and myosin light chain (MLC) phosphorylation, tight junction (TJ) protein expression and actin cytoskeletal organization were examined after stretch. Significant increases in epithelial permeability were observed only in 2CLP monolayers at the 12% ΔSA stretch level, and in both 2CLP and sham monolayers at the 25% ΔSA stretch level. Increased permeability in 2CLP monolayers was not associated with MAPk signaling or alterations in expression of TJ proteins. 2CLP monolayers had fewer actin stress fibers before stretch, a more robust stretch-induced actin redistribution, and reduced phosphorylated MLCK than sham monolayers. Jasplakinolide stabilization of the actin cytoskeleton in 2CLP monolayers prevented significant increases in permeability following 60 minutes of stretch to 12% ΔSA. We concluded that septic alveolar epithelial monolayers are more susceptible to stretch-induced barrier dysfunction than healthy monolayers due to actin reorganization.
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Affiliation(s)
- Taylor S. Cohen
- Department of Bioengineering, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Brian C. DiPaolo
- Department of Bioengineering, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Gladys Gray Lawrence
- Department of Bioengineering, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Susan S. Margulies
- Department of Bioengineering, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
- * E-mail:
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23
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Abstract
Tight junctions are the most apically localized part of the epithelial junctional complex. They regulate the permeability and polarity of cell layers and create compartments in cell membranes. Claudins are structural molecules of tight junctions. There are 27 claudins known, and expression of different claudins is responsible for changes in the electrolyte and solute permeability in cells layers. Studies have shown that claudins and tight junctions also protect multicellular organisms from infections and that some infectious agents may use claudins as targets to invade and weaken the host's defense. In neoplastic diseases, claudin expression may be up- or downregulated. Since their expression is associated with specific tumor types or with specific locations of tumors to a certain degree, they can, in a restricted sense, also be used as tumor markers. However, the regulation of claudin expression is complex involving growth factors and integrins, protein kinases, proto-oncogens and transcription factors. In this review, the significance of claudins is discussed in lung disease and development.
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Affiliation(s)
- Ylermi Soini
- Department of Pathology and Forensic Medicine, Institute of Clinical Medicine, Pathology and Forensic Medicine, School of Medicine, University of Eastern Finland, Cancer Center of Eastern Finland, PO Box 1627, FI-70211 Kuopio, Finland.
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Baloglu E, Reingruber T, Bärtsch P, Mairbäurl H. β2-Adrenergics in hypoxia desensitize receptors but blunt inhibition of reabsorption in rat lungs. Am J Respir Cell Mol Biol 2011; 45:1059-68. [PMID: 21562317 DOI: 10.1165/rcmb.2010-0273oc] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Alveolar edema and decreased inspired Po(2) decrease the oxygen supply to alveolar epithelia, impairing β(2)-adrenergic receptor (β2AR) signaling and alveolar reabsorption. β2AR agonists potently stimulate alveolar reabsorption. Thus, hypoxia impairs a major defense mechanism that provides protection from alveolar edema. Because in vivo data on the combined effects of prolonged hypoxia and β2AR agonist treatment on β2AR signaling are sparse, we tested whether in vivo hypoxia augments the inactivation of β2AR during prolonged stimulation. Rats were exposed to normoxia (N) and hypoxia (8% O(2); H), and were also treated with terbutaline (T; 2.5 mg/kg, intraperitoneal, twice daily) or saline (S) for 4 days. β2AR signaling was studied in alveolar epithelial (ATII) cells and in whole-lung tissue from treated rats. The terbutaline-stimulated formation of cyclic adenosine monophosphate was decreased by approximately 40% in whole lung and in ATII cells of NT, HS, and HT. The effects were not additive. The β2AR number was increased in HS, but decreased in NT and HT. Treatment increased the G-protein-coupled receptor kinase 2 protein in the plasma membranes of ATII cells, but did not affect G proteins. In vivo hypoxia significantly decreased total and amiloride-sensitive alveolar fluid reabsorption, which was prevented by acute alveolar treatment and 4 days of systemic terbutaline treatment. The αENaC (subunit of epithelial Na channels) protein in plasma membranes was increased in HT, without effects on mRNA. These results indicate that prolonged alveolar hypoxia and treatment with terbutaline impaired β2AR signaling in alveolar epithelia and in whole lungs, and this signaling was not further impaired by hypoxia. Despite impaired β2AR signaling, treatment with terbutaline for 4 days prevented the inhibition of alveolar reabsorption caused by in vivo hypoxia.
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Affiliation(s)
- Emel Baloglu
- Medical Clinic VII, Sports Medicine, University Hospital Heidelberg, University of Heidelberg, Germany
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25
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Mitchell LA, Overgaard CE, Ward C, Margulies SS, Koval M. Differential effects of claudin-3 and claudin-4 on alveolar epithelial barrier function. Am J Physiol Lung Cell Mol Physiol 2011; 301:L40-9. [PMID: 21515662 DOI: 10.1152/ajplung.00299.2010] [Citation(s) in RCA: 85] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Alveolar barrier function depends critically on the claudin family tight junction proteins. Of the major claudins expressed by alveolar epithelial cells, claudin (Cldn)-3 and Cldn-4 are the most closely related by amino acid homology, yet they differ dramatically in the pattern of expression. Previously published reports have shown that Cldn-3 is predominantly expressed by type II alveolar epithelial cells; Cldn-4 is expressed throughout the alveolar epithelium and is specifically upregulated in response to acute lung injury. Using primary rat alveolar epithelial cells transduced with yellow fluorescent protein-tagged claudin constructs, we have identified roles for Cldn-3 and Cldn-4 in alveolar epithelial barrier function. Surprisingly, increasing expression of Cldn-3 decreased alveolar epithelial barrier function, as assessed by transepithelial resistance and dye flux measurements. Conversely, increasing Cldn-4 expression improved alveolar epithelial transepithelial resistance compared with control cells. Other alveolar epithelial tight junction proteins were largely unaffected by increased expression of Cldn-3 and Cldn-4. Taken together, these results demonstrate that, in the context of the alveolar epithelium, Cldn-3 and Cldn-4 have different effects on paracellular permeability, despite significant homology in their extracellular loop domains.
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Affiliation(s)
- Leslie A Mitchell
- Division of Pulmonary, Allergy, and Critical Care Medicine, Department of Medicine, Emory University, Atlanta, Georgia 30322, USA
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26
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Koval M. Keratinocyte growth factor improves alveolar barrier function: keeping claudins in line. Am J Physiol Lung Cell Mol Physiol 2010; 299:L721-3. [PMID: 20952495 DOI: 10.1152/ajplung.00365.2010] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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