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Liu Y, Ge X, Li C, Xue T. Derivation and characterization of new cell line from intestine of turbot (Scophthalmus maximus). In Vitro Cell Dev Biol Anim 2023; 59:153-162. [PMID: 36809593 PMCID: PMC10073165 DOI: 10.1007/s11626-022-00746-y] [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: 09/14/2022] [Accepted: 12/09/2022] [Indexed: 02/23/2023]
Abstract
A continuous intestine cell line from turbot (Scophthalmus maximus) designated as SMI was established utilizing the tissue explant technique. Primary SMI cell was cultured at 24 °C in a medium with 20% fetal bovine serum (FBS), then subcultured in 10% FBS after 10 passages. Impacts of medium or temperature on the growth of SMI were examined and the results indicated it grew well in DMEM supplemented with 10% FBS at 24 °C. The SMI cell line was subcultured more than 60 times. Karyotyping, chromosome number, and ribosomal RNA genotyping analysis revealed that SMI had a modal diploid chromosome number of 44 and originated from turbot. After being transfected with pEGFP-N1 and FAM-siRNA, a large number of green fluorescence signals were observed in SMI, indicating that SMI could be used as an ideal platform to explore gene function in vitro. In addition, the expression of epithelium-associated genes such as itga6, itgb4, gja1, claudin1, zo-1, and E-cadherin in SMI suggested the SMI had some characteristics of epidermal cells. The upregulation of immune-associated genes such as TNF-β, NF-κB, and IL-1β in SMI after stimulation with pathogen-associated molecular patterns suggested the SMI might exhibit immune functions similar to the intestinal epithelium in vivo.
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Affiliation(s)
- Yiping Liu
- School of Marine Science and Engineering, Qingdao Agricultural University, Qingdao, 266109, China
| | - Xuefeng Ge
- School of Marine Science and Engineering, Qingdao Agricultural University, Qingdao, 266109, China
| | - Chao Li
- School of Marine Science and Engineering, Qingdao Agricultural University, Qingdao, 266109, China.
| | - Ting Xue
- School of Marine Science and Engineering, Qingdao Agricultural University, Qingdao, 266109, China.
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2
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Vega JL, Gutiérrez C, Rojas M, Güiza J, Sáez JC. Contribution of large-pore channels to inflammation induced by microorganisms. Front Cell Dev Biol 2023; 10:1094362. [PMID: 36699007 PMCID: PMC9868820 DOI: 10.3389/fcell.2022.1094362] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2022] [Accepted: 12/22/2022] [Indexed: 01/12/2023] Open
Abstract
Plasma membrane ionic channels selectively permeate potassium, sodium, calcium, and chloride ions. However, large-pore channels are permeable to ions and small molecules such as ATP and glutamate, among others. Large-pore channels are structures formed by several protein families with little or no evolutionary linkages including connexins (Cxs), pannexins (Panxs), innexin (Inxs), unnexins (Unxs), calcium homeostasis modulator (CALHMs), and Leucine-rich repeat-containing 8 (LRRC8) proteins. Large-pore channels are key players in inflammatory cell response, guiding the activation of inflammasomes, the release of pro-inflammatory cytokines such as interleukin-1 beta (IL-1ß), and the release of adenosine-5'-triphosphate (ATP), which is considered a danger signal. This review summarizes our current understanding of large-pore channels and their contribution to inflammation induced by microorganisms, virulence factors or their toxins.
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Affiliation(s)
- José L. Vega
- Laboratory of Gap Junctions Proteins and Parasitic Diseases (GaPaL), Instituto Antofagasta, Universidad de Antofagasta, Antofagasta, Chile,Centro de Investigación en Inmunología y Biotecnología Biomédica de Antofagasta (CIIBBA), Universidad de Antofagasta, Antofagasta, Chile,Centro de Fisiología y Medicina de Altura (FIMEDALT), Universidad de Antofagasta, Antofagasta, Chile,*Correspondence: José L. Vega,
| | - Camila Gutiérrez
- Laboratory of Gap Junctions Proteins and Parasitic Diseases (GaPaL), Instituto Antofagasta, Universidad de Antofagasta, Antofagasta, Chile
| | - Mauro Rojas
- Laboratory of Gap Junctions Proteins and Parasitic Diseases (GaPaL), Instituto Antofagasta, Universidad de Antofagasta, Antofagasta, Chile
| | - Juan Güiza
- Laboratory of Gap Junctions Proteins and Parasitic Diseases (GaPaL), Instituto Antofagasta, Universidad de Antofagasta, Antofagasta, Chile
| | - Juan C. Sáez
- Centro Interdisciplinario de Neurociencias de Valparaíso (CINV), Instituto de Neurociencias, Universidad de Valparaíso, Valparaíso, Chile
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3
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Gokulan K, Cerniglia CE, Thomas C, Pineiro SA, Khare S. Effects of residual levels of tetracycline on the barrier functions of human intestinal epithelial cells. Food Chem Toxicol 2017; 109:253-263. [DOI: 10.1016/j.fct.2017.09.004] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2017] [Revised: 08/30/2017] [Accepted: 09/02/2017] [Indexed: 12/12/2022]
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Diezmos EF, Bertrand PP, Liu L. Purinergic Signaling in Gut Inflammation: The Role of Connexins and Pannexins. Front Neurosci 2016; 10:311. [PMID: 27445679 PMCID: PMC4925662 DOI: 10.3389/fnins.2016.00311] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2016] [Accepted: 06/20/2016] [Indexed: 12/13/2022] Open
Abstract
Purinergic receptors play an important role in inflammation, and can be activated by ATP released via pannexin channels and/or connexin hemichannels. The purinergic P2X7 receptor (P2X7R) is of interest since it is involved in apoptosis when activated. Most studies focus on the influence of pannexin-1 (Panx1) and connexin 43 (Cx43) on ATP release and how it affects P2X7R function during inflammation. Inflammatory bowel disease (IBD) is characterized by uncontrolled inflammation within the gastrointestinal system. At present, the pathophysiology of this disease remains largely unknown but it may involve the interplay between P2X7R, Panx1, and Cx43. There are two main types of IBD, ulcerative colitis and Crohn's disease, that are classified by their location and frequency of inflammation. Current research suggests that alterations to normal functioning of innate and adaptive immunity may be a factor in disease progression. The involvement of purinergic receptors, connexins, and pannexins in IBD is a relatively novel notion in the context of gastrointestinal inflammation, and has been explored by various research groups. Thus, the present review focuses on the current research involving connexins, pannexins, and purinergic receptors within the gut and enteric nervous system, and will examine their involvement in inflammation and the pathophysiology of IBD.
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Affiliation(s)
- Erica F Diezmos
- School of Medical Sciences, University of New South Wales Sydney, NSW, Australia
| | - Paul P Bertrand
- School of Medical Sciences, University of New South WalesSydney, NSW, Australia; School of Medical Sciences, RMIT UniversityBundoora, VIC, Australia
| | - Lu Liu
- School of Medical Sciences, University of New South Wales Sydney, NSW, Australia
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5
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Ross KF, Herzberg MC. Autonomous immunity in mucosal epithelial cells: fortifying the barrier against infection. Microbes Infect 2016; 18:387-398. [PMID: 27005450 DOI: 10.1016/j.micinf.2016.03.008] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2016] [Revised: 03/09/2016] [Accepted: 03/10/2016] [Indexed: 12/19/2022]
Abstract
Mucosal epithelial cells express an autonomous innate immune response that controls the overgrowth of invaded bacteria, mitigates the harmful effects of the bacteria carried within, and does not rely on other external arms of the immune response. Epithelial cell autonomous innate immunity "respects" the social biology of invading bacteria to achieve symbiosis, and is the primary protective mechanism against pathogens.
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Affiliation(s)
- Karen F Ross
- Department of Diagnostic and Biological Sciences, School of Dentistry, University of Minnesota, USA
| | - Mark C Herzberg
- Department of Diagnostic and Biological Sciences, School of Dentistry, University of Minnesota, USA.
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Bonnet M, Tran Van Nhieu G. How Shigella Utilizes Ca(2+) Jagged Edge Signals during Invasion of Epithelial Cells. Front Cell Infect Microbiol 2016; 6:16. [PMID: 26904514 PMCID: PMC4748038 DOI: 10.3389/fcimb.2016.00016] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2015] [Accepted: 01/25/2016] [Indexed: 12/20/2022] Open
Abstract
Shigella, the causative agent of bacillary dysentery invades intestinal epithelial cells using a type III secretion system (T3SS). Through the injection of type III effectors, Shigella manipulates the actin cytoskeleton to induce its internalization in epithelial cells. At early invasion stages, Shigella induces atypical Ca(2+) responses confined at entry sites allowing local cytoskeletal remodeling for bacteria engulfment. Global Ca(2+) increase in the cell triggers the opening of connexin hemichannels at the plasma membrane that releases ATP in the extracellular milieu, favoring Shigella invasion and spreading through purinergic receptor signaling. During intracellular replication, Shigella regulates inflammatory and death pathways to disseminate within the epithelium. At later stages of infection, Shigella downregulates hemichannel opening and the release of extracellular ATP to dampen inflammatory signals. To avoid premature cell death, Shigella activates cell survival by upregulating the PI3K/Akt pathway and downregulating the levels of p53. Furthermore, Shigella interferes with pro-apoptotic caspases, and orients infected cells toward a slow necrotic cell death linked to mitochondrial Ca(2+) overload. In this review, we will focus on the role of Ca(2+) responses and their regulation by Shigella during the different stages of bacterial infection.
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Affiliation(s)
- Mariette Bonnet
- Equipe Communication Intercellulaire et Infections Microbiennes, Centre de Recherche Interdisciplinaire en Biologie, Collège de FranceParis, France; Institut National de la Santé et de la Recherche Médicale U1050Paris, France; Centre National de la Recherche Scientifique, UMR7241Paris, France; MEMOLIFE Laboratory of Excellence and Paris Science LettreParis, France
| | - Guy Tran Van Nhieu
- Equipe Communication Intercellulaire et Infections Microbiennes, Centre de Recherche Interdisciplinaire en Biologie, Collège de FranceParis, France; Institut National de la Santé et de la Recherche Médicale U1050Paris, France; Centre National de la Recherche Scientifique, UMR7241Paris, France; MEMOLIFE Laboratory of Excellence and Paris Science LettreParis, France
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Chen J, Li L, Li Y, Liang X, Sun Q, Yu H, Zhong J, Ni Y, Chen J, Zhao Z, Gao P, Wang B, Liu D, Zhu Z, Yan Z. Activation of TRPV1 channel by dietary capsaicin improves visceral fat remodeling through connexin43-mediated Ca2+ influx. Cardiovasc Diabetol 2015; 14:22. [PMID: 25849380 PMCID: PMC4340344 DOI: 10.1186/s12933-015-0183-6] [Citation(s) in RCA: 77] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/01/2014] [Accepted: 01/24/2015] [Indexed: 02/06/2023] Open
Abstract
Background The prevalence of obesity has dramatically increased worldwide and has attracted rising attention, but the mechanism is still unclear. Previous studies revealed that transient receptor potential vanilloid 1 (TRPV1) channels take part in weight loss by enhancing intracellular Ca2+ levels. However, the potential mechanism of the effect of dietary capsaicin on obesity is not completely understood. Ca2+ transfer induced by connexin43 (Cx43) molecules between coupled cells takes part in adipocyte differentiation. Whether TRPV1-evoked alterations in Cx43-mediated adipocyte-to-adipocyte communication play a role in obesity is unknown. Materials and methods We investigated whether Cx43 participated in TRPV1-mediated adipocyte lipolysis in cultured 3T3-L1 preadipocytes and visceral adipose tissues from humans and wild-type (WT) and TRPV1-deficient (TRPV1-/-) mice. Results TRPV1 and Cx43 co-expressed in mesenteric adipose tissue. TRPV1 activation by capsaicin increased the influx of Ca2+ in 3T3-L1 preadipocytes and promoted cell lipolysis, as shown by Oil-red O staining. These effects were deficient when capsazepine, a TRPV1 antagonist, and 18 alpha-glycyrrhetinic acid (18α-GA), a gap-junction inhibitor, were administered. Long-term chronic dietary capsaicin reduced the weights of perirenal, mesenteric and testicular adipose tissues in WT mice fed a high-fat diet. Capsaicin increased the expression levels of p-CaM, Cx43, CaMKII, PPARδ and HSL in mesenteric adipose tissues from WT mice fed a high-fat diet, db/db mice, as well as obese humans, but these effects of capsaicin were absent in TRPV1-/- mice. Long-term chronic dietary capsaicin decreased the body weights and serum lipids of WT mice, but not TRPV1-/- mice, fed a high-fat diet. Conclusion This study demonstrated that capsaicin activation of TRPV1-evoked increased Ca2+ influx in Cx43-mediated adipocyte-to-adipocyte communication promotes lipolysis in both vitro and vivo. TRPV1 activation by dietary capsaicin improves visceral fat remodeling through the up-regulation of Cx43.
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Bou Saab J, Losa D, Chanson M, Ruez R. Connexins in respiratory and gastrointestinal mucosal immunity. FEBS Lett 2014; 588:1288-96. [PMID: 24631537 DOI: 10.1016/j.febslet.2014.02.059] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2014] [Revised: 02/27/2014] [Accepted: 02/27/2014] [Indexed: 12/18/2022]
Abstract
The mucosal lining forms the physical and chemical barrier that protects against pathogens and hostile particles and harbors its own population of bacteria, fungi and archea, known as the microbiota. The immune system controls tolerance of this population of microorganisms that have proven to be beneficial for its host. Keeping its physical integrity and a correct balance with the microbiota, the mucosa preserves its homeostasis and its protective function and maintains host's health. However, in some conditions, pathogens may succeed in breaching mucosal homeostasis and successfully infecting the host. In this review we will discuss the role the mucosa plays in the defense against bacterial pathogens by considering the gap junction protein connexins. We will detail their implication in mucosal homeostasis and upon infection with bacteria in the respiratory and the gastrointestinal tracts.
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Affiliation(s)
- Joanna Bou Saab
- Geneva University Hospitals and University of Geneva, Geneva, Switzerland
| | - Davide Losa
- Geneva University Hospitals and University of Geneva, Geneva, Switzerland
| | - Marc Chanson
- Geneva University Hospitals and University of Geneva, Geneva, Switzerland.
| | - Richard Ruez
- Geneva University Hospitals and University of Geneva, Geneva, Switzerland
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9
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Eugenin EA. Role of connexin/pannexin containing channels in infectious diseases. FEBS Lett 2014; 588:1389-95. [PMID: 24486013 DOI: 10.1016/j.febslet.2014.01.030] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2013] [Revised: 01/20/2014] [Accepted: 01/21/2014] [Indexed: 12/12/2022]
Abstract
In recent years it has become evident that gap junctions and hemichannels, in concert with extracellular ATP and purinergic receptors, play key roles in several physiological processes and pathological conditions. However, only recently has their importance in infectious diseases been explored, likely because early reports indicated that connexin containing channels were completely inactivated under inflammatory conditions, and therefore no further research was performed. However, recent evidence indicates that several infectious agents take advantage of these communication systems to enhance inflammation and apoptosis, as well as to participate in the infectious cycle of several pathogens. In the current review, we will discuss the role of these channels/receptors in the pathogenesis of several infectious diseases and the possibilities of generating novel therapeutic approaches to reduce or prevent these diseases.
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Affiliation(s)
- Eliseo A Eugenin
- Public Health Research Institute (PHRI), Rutgers New Jersey Medical School, Rutgers The State University of New Jersey, Newark, NJ, USA; Department of Microbiology and Molecular Genetics, Rutgers New Jersey Medical School, Rutgers The State University of New Jersey, Newark, NJ, USA.
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Nielsen MS, Axelsen LN, Sorgen PL, Verma V, Delmar M, Holstein-Rathlou NH. Gap junctions. Compr Physiol 2013; 2:1981-2035. [PMID: 23723031 DOI: 10.1002/cphy.c110051] [Citation(s) in RCA: 289] [Impact Index Per Article: 26.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Gap junctions are essential to the function of multicellular animals, which require a high degree of coordination between cells. In vertebrates, gap junctions comprise connexins and currently 21 connexins are known in humans. The functions of gap junctions are highly diverse and include exchange of metabolites and electrical signals between cells, as well as functions, which are apparently unrelated to intercellular communication. Given the diversity of gap junction physiology, regulation of gap junction activity is complex. The structure of the various connexins is known to some extent; and structural rearrangements and intramolecular interactions are important for regulation of channel function. Intercellular coupling is further regulated by the number and activity of channels present in gap junctional plaques. The number of connexins in cell-cell channels is regulated by controlling transcription, translation, trafficking, and degradation; and all of these processes are under strict control. Once in the membrane, channel activity is determined by the conductive properties of the connexin involved, which can be regulated by voltage and chemical gating, as well as a large number of posttranslational modifications. The aim of the present article is to review our current knowledge on the structure, regulation, function, and pharmacology of gap junctions. This will be supported by examples of how different connexins and their regulation act in concert to achieve appropriate physiological control, and how disturbances of connexin function can lead to disease.
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Affiliation(s)
- Morten Schak Nielsen
- Department of Biomedical Sciences and The Danish National Research Foundation Centre for Cardiac Arrhythmia, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark
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11
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Connexins form functional hemichannels in porcine ciliary epithelium. Exp Eye Res 2013; 118:20-9. [PMID: 24262135 DOI: 10.1016/j.exer.2013.11.004] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2013] [Revised: 11/05/2013] [Accepted: 11/11/2013] [Indexed: 01/20/2023]
Abstract
The expression of connexins in the ciliary epithelium is consistent with gap junctions between the pigmented (PE) and nonpigmented ciliary epithelium (NPE) that form when connexon hemichannels from adjacent cells pair to form a channel. Here we present evidence that suggests undocked connexons may form functional hemichannels that permit exchange of substances between NPE and the aqueous humor. Intact porcine eyes were perfused via the ciliary artery and propidium iodide (PI) (MW 668) was added to the aqueous humor compartment as a tracer. After calcium-free solution containing PI was introduced into the aqueous humor compartment for 30 min, fluorescence microscopy revealed PI in the NPE cell layer. PI entry into the NPE was inhibited by calcium and by the connexin antagonist 18α-glycyrrhetinic acid (18-AGA). Studies also were carried out with cultured porcine NPE. Under normal conditions, little PI entered the cultured cells but calcium-free medium stimulated PI accumulation and the entry was inhibited by 18-AGA. In cells loaded with calcein (MW 622), calcium-free solution stimulated calcein exit. 18-AGA partially suppressed calcein exit in calcium-free medium. Connexin 43 and connexin 50 proteins were detected by western blot analysis in both native and cultured NPE. In the intact eye, immunolocalization studies revealed connexin 50 at the basolateral, aqueous humor-facing, margin of the NPE. In contrast, connexin 43 was observed at the junction of the PE and NPE layer and on the basolateral membrane of PE. The results point to functional hemichannels at the NPE basolateral surface. It is feasible that hemichannels might contribute to the transfer of substances between the ciliary epithelium cytoplasm and aqueous humor.
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12
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Role of gap junctions and hemichannels in parasitic infections. BIOMED RESEARCH INTERNATIONAL 2013; 2013:589130. [PMID: 24236292 PMCID: PMC3819887 DOI: 10.1155/2013/589130] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/21/2013] [Revised: 08/07/2013] [Accepted: 08/26/2013] [Indexed: 02/06/2023]
Abstract
In vertebrates, connexins (Cxs) and pannexins (Panxs) are proteins that form gap junction channels and/or hemichannels located at cell-cell interfaces and cell surface, respectively. Similar channel types are formed by innexins in invertebrate cells. These channels serve as pathways for cellular communication that coordinate diverse physiologic processes. However, it is known that many acquired and inherited diseases deregulate Cx and/or Panx channels, condition that frequently worsens the pathological state of vertebrates. Recent evidences suggest that Cx and/or Panx hemichannels play a relevant role in bacterial and viral infections. Nonetheless, little is known about the role of Cx- and Panx-based channels in parasitic infections of vertebrates. In this review, available data on changes in Cx and gap junction channel changes induced by parasitic infections are summarized. Additionally, we describe recent findings that suggest possible roles of hemichannels in parasitic infections. Finally, the possibility of new therapeutic designs based on hemichannel blokers is presented.
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Ceelen L, Haesebrouck F, Vanhaecke T, Rogiers V, Vinken M. Modulation of connexin signaling by bacterial pathogens and their toxins. Cell Mol Life Sci 2011; 68:3047-64. [PMID: 21656255 PMCID: PMC11115019 DOI: 10.1007/s00018-011-0737-z] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2011] [Revised: 05/12/2011] [Accepted: 05/17/2011] [Indexed: 02/07/2023]
Abstract
Inherent to their pivotal tasks in the maintenance of cellular homeostasis, gap junctions, connexin hemichannels, and pannexin hemichannels are frequently involved in the dysregulation of this critical balance. The present paper specifically focuses on their roles in bacterial infection and disease. In particular, the reported biological outcome of clinically important bacteria including Escherichia coli, Shigella flexneri, Yersinia enterocolitica, Helicobacter pylori, Bordetella pertussis, Aggregatibacter actinomycetemcomitans, Pseudomonas aeruginosa, Citrobacter rodentium, Clostridium species, Streptococcus pneumoniae, and Staphylococcus aureus and their toxic products on connexin- and pannexin-related signaling in host cells is reviewed. Particular attention is paid to the underlying molecular mechanisms of these effects as well as to the actual biological relevance of these findings.
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Affiliation(s)
- Liesbeth Ceelen
- Department of Toxicology, Centre for Pharmaceutical Research, Faculty of Medicine and Pharmacy, Vrije Universiteit Brussel, Laarbeeklaan 103, 1090 Brussels, Belgium.
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Abstract
Cx (connexin) proteins are components of gap junctions which are aqueous pores that allow intercellular exchange of ions and small molecules. Mutations in Cx genes are linked to a range of human disorders. In the present review we discuss mutations in β-Cx genes encoding Cx26, Cx30, Cx30.3 and Cx31 which lead to skin disease and deafness. Functional studies with Cx proteins have given insights into disease-associated mechanisms and non-gap junctional roles for Cx proteins.
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D'hondt C, Ponsaerts R, De Smedt H, Bultynck G, Himpens B. Pannexins, distant relatives of the connexin family with specific cellular functions? Bioessays 2009; 31:953-74. [PMID: 19644918 DOI: 10.1002/bies.200800236] [Citation(s) in RCA: 131] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Intercellular communication (IC) is mediated by gap junctions (GJs) and hemichannels, which consist of proteins. This has been particularly well documented for the connexin (Cx) family. Initially, Cxs were thought to be the only proteins capable of GJ formation in vertebrates. About 10 years ago, however, a new GJ-forming protein family related to invertebrate innexins (Inxs) was discovered in vertebrates, and named the pannexin (Panx) family. Panxs, which are structurally similar to Cxs, but evolutionarily distinct, have been shown to be co-expressed with Cxs in vertebrates. Both protein families show distinct properties and have their own particular function. Identification of the mechanisms that control Panx channel gating is a major challenge for future work. In this review, we focus on the specific properties and role of Panxs in normal and pathological conditions.
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Affiliation(s)
- Catheleyne D'hondt
- Laboratory of Molecular and Cellular Signalling, KULeuven, Campus Gasthuisberg O/N, Leuven, Belgium
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Ey B, Eyking A, Gerken G, Podolsky DK, Cario E. TLR2 mediates gap junctional intercellular communication through connexin-43 in intestinal epithelial barrier injury. J Biol Chem 2009; 284:22332-22343. [PMID: 19528242 DOI: 10.1074/jbc.m901619200] [Citation(s) in RCA: 91] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Gap junctional intercellular communication (GJIC) coordinates cellular functions essential for sustaining tissue homeostasis; yet its regulation in the intestine is not well understood. Here, we identify a novel physiological link between Toll-like receptor (TLR) 2 and GJIC through modulation of Connexin-43 (Cx43) during acute and chronic inflammatory injury of the intestinal epithelial cell (IEC) barrier. Data from in vitro studies reveal that TLR2 activation modulates Cx43 synthesis and increases GJIC via Cx43 during IEC injury. The ulcerative colitis-associated TLR2-R753Q mutant targets Cx43 for increased proteasomal degradation, impairing TLR2-mediated GJIC during intestinal epithelial wounding. In vivo studies using mucosal RNA interference show that TLR2-mediated mucosal healing depends functionally on intestinal epithelial Cx43 during acute inflammatory stress-induced damage. Mice deficient in TLR2 exhibit IEC-specific alterations in Cx43, whereas administration of a TLR2 agonist protects GJIC by blocking accumulation of Cx43 and its hyperphosphorylation at Ser368 to prevent spontaneous chronic colitis in MDR1alpha-deficient mice. Finally, adding the TLR2 agonist to three-dimensional intestinal mucosa-like cultures of human biopsies preserves intestinal epithelial Cx43 integrity and polarization ex vivo. In conclusion, Cx43 plays an important role in innate immune control of commensal-mediated intestinal epithelial wound repair.
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Affiliation(s)
- Birgit Ey
- Division of Gastroenterology and Hepatology, University Hospital of Essen, and Medical School, University of Duisburg-Essen, 45147 Essen, Germany
| | - Annette Eyking
- Division of Gastroenterology and Hepatology, University Hospital of Essen, and Medical School, University of Duisburg-Essen, 45147 Essen, Germany
| | - Guido Gerken
- Division of Gastroenterology and Hepatology, University Hospital of Essen, and Medical School, University of Duisburg-Essen, 45147 Essen, Germany
| | - Daniel K Podolsky
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas 75390
| | - Elke Cario
- Division of Gastroenterology and Hepatology, University Hospital of Essen, and Medical School, University of Duisburg-Essen, 45147 Essen, Germany
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