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Ehrlich A, Pelli G, Pick R, Clochard L, Molica F, Kwak BR. Pannexin1 deletion in lymphatic endothelium affects lymphatic function in a sex-dependent manner. Physiol Rep 2024; 12:e16170. [PMID: 39085909 PMCID: PMC11291012 DOI: 10.14814/phy2.16170] [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: 01/24/2024] [Revised: 07/23/2024] [Accepted: 07/23/2024] [Indexed: 08/02/2024] Open
Abstract
The lymphatic network of capillaries and collecting vessels ensures tissue fluid homeostasis, absorption of dietary fats and trafficking of immune cells. Pannexin1 (Panx1) channels allow for the passage of ions and small metabolites between the cytosol and extracellular environment. Panx1 channels regulate the pathophysiological function of several tissues in a sex-dependent manner. Here, we studied the role of Panx1 in lymphatic function, and potential sex-dependent differences therein, in Prox1-CreERT2Panx1fl/fl and Panx1fl/fl control mice. Panx1 expression was higher in lymphatic endothelial cells (LECs) of male mice. Lymphatic vessel morphology was not affected in Prox1-CreERT2Panx1fl/fl male and female mice. Lymphatic drainage was decreased by 25% in male Prox1-CreERT2Panx1fl/fl mice, but was similar in females of both genotypes. Accordingly, only male Prox1-CreERT2Panx1fl/fl mice exhibited tail swelling, pointing to interstitial fluid accumulation in males upon Panx1 deletion in LECs. Moreover, serum triglyceride and free fatty acid levels raised less in Prox1-CreERT2Panx1fl/fl mice of both sexes in an oral lipid tolerance test. Finally, the percentage of migratory dendritic cells arriving in draining lymph nodes was increased in Prox1-CreERT2Panx1fl/fl female mice, but was comparable between male mice of both genotypes. Our results point to a LEC-specific role for Panx1 in the functions of the lymphatic system.
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Affiliation(s)
- Avigail Ehrlich
- Department of Pathology and Immunology (PATIM)University of GenevaGenevaSwitzerland
- Geneva Center for Inflammation Research (GCIR), Faculty of MedicineUniversity of GenevaGenevaSwitzerland
| | - Graziano Pelli
- Department of Pathology and Immunology (PATIM)University of GenevaGenevaSwitzerland
- Geneva Center for Inflammation Research (GCIR), Faculty of MedicineUniversity of GenevaGenevaSwitzerland
| | - Robert Pick
- Department of Pathology and Immunology (PATIM)University of GenevaGenevaSwitzerland
- Geneva Center for Inflammation Research (GCIR), Faculty of MedicineUniversity of GenevaGenevaSwitzerland
| | - Linda Clochard
- Department of Pathology and Immunology (PATIM)University of GenevaGenevaSwitzerland
- Geneva Center for Inflammation Research (GCIR), Faculty of MedicineUniversity of GenevaGenevaSwitzerland
| | - Filippo Molica
- Department of Pathology and Immunology (PATIM)University of GenevaGenevaSwitzerland
- Geneva Center for Inflammation Research (GCIR), Faculty of MedicineUniversity of GenevaGenevaSwitzerland
| | - Brenda R. Kwak
- Department of Pathology and Immunology (PATIM)University of GenevaGenevaSwitzerland
- Geneva Center for Inflammation Research (GCIR), Faculty of MedicineUniversity of GenevaGenevaSwitzerland
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2
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Davis MJ, Castorena-Gonzalez JA, Li M, Zawieja SD, Simon AM, Geng X, Srinivasan RS. Connexin-45 is expressed in mouse lymphatic endothelium and required for lymphatic valve function. JCI Insight 2024; 9:e169931. [PMID: 39074069 PMCID: PMC11343601 DOI: 10.1172/jci.insight.169931] [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: 03/13/2023] [Accepted: 07/11/2024] [Indexed: 07/31/2024] Open
Abstract
The expression and functional relevance of the gap junction molecule connexin-45 (Cx45; GJC1) in lymphatic endothelium were not previously known. We found that Cx45 was expressed widely in the endothelium of murine lymphatics, in both valve and nonvalve regions. Cell-specific deletion of Cx45, driven by a constitutive Cre line (Lyve1-Cre) or an inducible Cre line (Prox1-CreERT2), compromised the function of lymphatic valves, as assessed by physiological tests (back leak and closure) of isolated, single-valve vessel segments. The defects were comparable to those previously reported for loss of Cx43, and as with Cx43, deletion of Cx45 resulted in shortening or increased asymmetry of lymphatic valve leaflets, providing an explanation for the compromised valve function. In contrast with Cx43, lymphatic endothelial cell-specific (LEC-specific) deletion of Cx45 did not alter the number of valves in mesenteric or dermal lymphatic networks or the expression patterns of the canonical valve-associated proteins PROX1, ITGA9, or CLAUDIN5. Constitutive deletion of Cx45 from LECs resulted in increased backflow of injected tracer in popliteal networks in vivo and compromised the integrity of the LEC permeability barrier in a subset of collecting vessels. These findings provide evidence for an unexpected role of Cx45 in the development and maintenance of lymphatic valves.
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Affiliation(s)
- Michael J. Davis
- Department of Medical Pharmacology & Physiology, University of Missouri, Columbia, Missouri, USA
| | | | - Min Li
- Department of Medical Pharmacology & Physiology, University of Missouri, Columbia, Missouri, USA
| | - Scott D. Zawieja
- Department of Medical Pharmacology & Physiology, University of Missouri, Columbia, Missouri, USA
| | - Alex M. Simon
- Department of Physiology, University of Arizona School of Medicine, Tucson, Arizona, USA
| | - Xin Geng
- Cardiovascular Biology Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma, USA
| | - R. Sathish Srinivasan
- Cardiovascular Biology Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma, USA
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3
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Brouillard P, Witte MH, Erickson RP, Damstra RJ, Becker C, Quéré I, Vikkula M. Primary lymphoedema. Nat Rev Dis Primers 2021; 7:77. [PMID: 34675250 DOI: 10.1038/s41572-021-00309-7] [Citation(s) in RCA: 40] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 09/17/2021] [Indexed: 11/09/2022]
Abstract
Lymphoedema is the swelling of one or several parts of the body owing to lymph accumulation in the extracellular space. It is often chronic, worsens if untreated, predisposes to infections and causes an important reduction in quality of life. Primary lymphoedema (PLE) is thought to result from abnormal development and/or functioning of the lymphatic system, can present in isolation or as part of a syndrome, and can be present at birth or develop later in life. Mutations in numerous genes involved in the initial formation of lymphatic vessels (including valves) as well as in the growth and expansion of the lymphatic system and associated pathways have been identified in syndromic and non-syndromic forms of PLE. Thus, the current hypothesis is that most cases of PLE have a genetic origin, although a causative mutation is identified in only about one-third of affected individuals. Diagnosis relies on clinical presentation, imaging of the structure and functionality of the lymphatics, and in genetic analyses. Management aims at reducing or preventing swelling by compression therapy (with manual drainage, exercise and compressive garments) and, in carefully selected cases, by various surgical techniques. Individuals with PLE often have a reduced quality of life owing to the psychosocial and lifelong management burden associated with their chronic condition. Improved understanding of the underlying genetic origins of PLE will translate into more accurate diagnosis and prognosis and personalized treatment.
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Affiliation(s)
- Pascal Brouillard
- Human Molecular Genetics, de Duve Institute, University of Louvain, Brussels, Belgium
| | - Marlys H Witte
- Department of Surgery, Neurosurgery, and Pediatrics, University of Arizona College of Medicine, Tucson, AZ, USA
| | - Robert P Erickson
- Department of Pediatrics, University of Arizona College of Medicine, Tucson, AZ, USA
| | - Robert J Damstra
- VASCERN PPL European Reference Centre; Department of Dermatology, Phlebology and Lymphology, Nij Smellinghe Hospital, Drachten, Netherlands
| | | | - Isabelle Quéré
- Department of Vascular Medicine, Centre de référence des Maladies Lymphatiques et Vasculaires Rares, Inserm IDESP, CHU Montpellier, Université de Montpellier, Montpellier, France
| | - Miikka Vikkula
- Human Molecular Genetics, de Duve Institute, University of Louvain, Brussels, Belgium. .,VASCERN VASCA European Reference Centre; Center for Vascular Anomalies, Division of Plastic Surgery, University Clinics Saint-Luc, University of Louvain, Brussels, Belgium. .,Walloon Excellence in Lifesciences and Biotechnology (WELBIO), de Duve Institute, University of Louvain, Brussels, Belgium.
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4
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Martin-Almedina S, Mortimer PS, Ostergaard P. Development and physiological functions of the lymphatic system: insights from human genetic studies of primary lymphedema. Physiol Rev 2021; 101:1809-1871. [PMID: 33507128 DOI: 10.1152/physrev.00006.2020] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Primary lymphedema is a long-term (chronic) condition characterized by tissue lymph retention and swelling that can affect any part of the body, although it usually develops in the arms or legs. Due to the relevant contribution of the lymphatic system to human physiology, while this review mainly focuses on the clinical and physiological aspects related to the regulation of fluid homeostasis and edema, clinicians need to know that the impact of lymphatic dysfunction with a genetic origin can be wide ranging. Lymphatic dysfunction can affect immune function so leading to infection; it can influence cancer development and spread, and it can determine fat transport so impacting on nutrition and obesity. Genetic studies and the development of imaging techniques for the assessment of lymphatic function have enabled the recognition of primary lymphedema as a heterogenic condition in terms of genetic causes and disease mechanisms. In this review, the known biological functions of several genes crucial to the development and function of the lymphatic system are used as a basis for understanding normal lymphatic biology. The disease conditions originating from mutations in these genes are discussed together with a detailed clinical description of the phenotype and the up-to-date knowledge in terms of disease mechanisms acquired from in vitro and in vivo research models.
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Affiliation(s)
- Silvia Martin-Almedina
- Molecular and Clinical Sciences Institute, St. George's University of London, London, United Kingdom
| | - Peter S Mortimer
- Molecular and Clinical Sciences Institute, St. George's University of London, London, United Kingdom
- Dermatology and Lymphovascular Medicine, St. George's Universities NHS Foundation Trust, London, United Kingdom
| | - Pia Ostergaard
- Molecular and Clinical Sciences Institute, St. George's University of London, London, United Kingdom
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5
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Stavropoulos F, Georgiou E, Sargiannidou I, Kleopa KA. Dysregulation of Blood-Brain Barrier and Exacerbated Inflammatory Response in Cx47-Deficient Mice after Induction of EAE. Pharmaceuticals (Basel) 2021; 14:ph14070621. [PMID: 34203192 PMCID: PMC8308522 DOI: 10.3390/ph14070621] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2021] [Revised: 06/23/2021] [Accepted: 06/24/2021] [Indexed: 12/18/2022] Open
Abstract
Induction of experimental autoimmune encephalomyelitis (EAE), an animal model of multiple sclerosis (MS), in connexin 32 (Cx32) or Cx47 knockout (KO) mice with deficiency in oligodendrocyte gap junctions (GJs) results in a more severe disease course. In particular, Cx47 KO EAE mice experience an earlier EAE onset and more pronounced disease severity, accompanied by dysregulated pro-inflammatory responses preceding the disease manifestations. In this study, analysis of relevant pro-inflammatory cytokines in wild type EAE, Cx32 KO EAE, and Cx47 KO EAE mice revealed altered expression of Vcam-1 preceding EAE [7 days post injection (dpi)], of Ccl2 at the onset of EAE (12 dpi), and of Gm-csf at the peak of EAE (24 dpi) in Cx47 KO EAE mice. Moreover, Cx47 KO EAE mice exhibited more severe blood-spinal cord barrier (BSCB) disruption, enhanced astrogliosis with defects in tight junction formation at the glia limitans, and increased T-cell infiltration prior to disease onset. Thus, Cx47 deficiency appears to cause dysregulation of the inflammatory profile and BSCB integrity, promoting early astrocyte responses in Cx47 KO EAE mice that lead to a more severe EAE outcome. Further investigation into the role of oligodendrocytic Cx47 in EAE and multiple sclerosis pathology is warranted.
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Affiliation(s)
- Filippos Stavropoulos
- Neuroscience Department, The Cyprus Institute of Neurology and Genetics, Nicosia 2371, Cyprus; (F.S.); (E.G.); (I.S.)
| | - Elena Georgiou
- Neuroscience Department, The Cyprus Institute of Neurology and Genetics, Nicosia 2371, Cyprus; (F.S.); (E.G.); (I.S.)
| | - Irene Sargiannidou
- Neuroscience Department, The Cyprus Institute of Neurology and Genetics, Nicosia 2371, Cyprus; (F.S.); (E.G.); (I.S.)
| | - Kleopas A. Kleopa
- Neuroscience Department, The Cyprus Institute of Neurology and Genetics, Nicosia 2371, Cyprus; (F.S.); (E.G.); (I.S.)
- Center for Multiple Sclerosis and Related Disorders, The Cyprus Institute of Neurology and Genetics and Cyprus School of Molecular Medicine, Nicosia 2371, Cyprus
- Correspondence: ; Tel.: +357-22-358600; Fax: +357-22-392786
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6
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Lymphatic Connexins and Pannexins in Health and Disease. Int J Mol Sci 2021; 22:ijms22115734. [PMID: 34072103 PMCID: PMC8199429 DOI: 10.3390/ijms22115734] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2021] [Revised: 05/18/2021] [Accepted: 05/26/2021] [Indexed: 12/25/2022] Open
Abstract
This review highlights current knowledge on the expression and function of connexins and pannexins, transmembrane channel proteins that play an important role in intercellular communication, in both the developing and mature lymphatic vasculature. A particular focus is given to the involvement of these proteins in functions of the healthy lymphatic system. We describe their influence on the maintenance of extracellular fluid homeostasis, immune cell trafficking to draining lymph nodes and dietary nutrient absorption by intestinal villi. Moreover, new insights into connexin mutations in primary and secondary lymphedema as well as on the implication of lymphatic connexins and pannexins in acquired cardiovascular diseases are discussed, allowing for a better understanding of the role of these proteins in pathologies linked to dysfunctions in the lymphatic system.
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7
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Papaneophytou C, Georgiou E, Kleopa KA. The role of oligodendrocyte gap junctions in neuroinflammation. Channels (Austin) 2020; 13:247-263. [PMID: 31232168 PMCID: PMC6602578 DOI: 10.1080/19336950.2019.1631107] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
Abstract
Gap junctions (GJs) provide channels for direct cell-to-cell connectivity serving the homeostasis in several organs of vertebrates including the central (CNS) and peripheral (PNS) nervous systems. GJs are composed of connexins (Cx), which show a highly distinct cellular and subcellular expression pattern. Oligodendrocytes, the myelinating cells of the CNS, are characterized by extensive GJ connectivity with each other as well as with astrocytes. The main oligodendrocyte connexins forming these GJ channels are Cx47 and Cx32. The importance of these channels has been highlighted by the discovery of human diseases caused by mutations in oligodendrocyte connexins, manifesting with leukodystrophy or transient encephalopathy. Experimental models have provided further evidence that oligodendrocyte GJs are essential for CNS myelination and homeostasis, while a strong inflammatory component has been recognized in the absence of oligodendrocyte connexins. Further studies revealed that connexins are also disrupted in multiple sclerosis (MS) brain, and in experimental models of induced inflammatory demyelination. Moreover, induced demyelination was more severe and associated with higher degree of CNS inflammation in models with oligodendrocyte GJ deficiency, suggesting that disrupted connexin expression in oligodendrocytes is not only a consequence but can also drive a pro-inflammatory environment in acquired demyelinating disorders such as MS. In this review, we summarize the current insights from human disorders as well as from genetic and acquired models of demyelination related to oligodendrocyte connexins, with the remaining challenges and perspectives.
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Affiliation(s)
- Christos Papaneophytou
- a Neuroscience Laboratory, The Cyprus Institute of Neurology and Genetics and Cyprus School of Molecular Medicine , Nicosia , Cyprus.,b Department of Life and Health Sciences, School of Sciences and Engineering , University of Nicosia , Nicosia , Cyprus
| | - Elena Georgiou
- a Neuroscience Laboratory, The Cyprus Institute of Neurology and Genetics and Cyprus School of Molecular Medicine , Nicosia , Cyprus
| | - Kleopas A Kleopa
- a Neuroscience Laboratory, The Cyprus Institute of Neurology and Genetics and Cyprus School of Molecular Medicine , Nicosia , Cyprus.,c Neurology Clinics , the Cyprus Institute of Neurology and Genetics, and the Cyprus School of Molecular Medicine , Nicosia , Cyprus
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8
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Zhang F, Zarkada G, Yi S, Eichmann A. Lymphatic Endothelial Cell Junctions: Molecular Regulation in Physiology and Diseases. Front Physiol 2020; 11:509. [PMID: 32547411 PMCID: PMC7274196 DOI: 10.3389/fphys.2020.00509] [Citation(s) in RCA: 55] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2019] [Accepted: 04/27/2020] [Indexed: 12/13/2022] Open
Abstract
Lymphatic endothelial cells (LECs) lining lymphatic vessels develop specialized cell-cell junctions that are crucial for the maintenance of vessel integrity and proper lymphatic vascular functions. Successful lymphatic drainage requires a division of labor between lymphatic capillaries that take up lymph via open "button-like" junctions, and collectors that transport lymph to veins, which have tight "zipper-like" junctions that prevent lymph leakage. In recent years, progress has been made in the understanding of these specialized junctions, as a result of the application of state-of-the-art imaging tools and novel transgenic animal models. In this review, we discuss lymphatic development and mechanisms governing junction remodeling between button and zipper-like states in LECs. Understanding lymphatic junction remodeling is important in order to unravel lymphatic drainage regulation in obesity and inflammatory diseases and may pave the way towards future novel therapeutic interventions.
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Affiliation(s)
- Feng Zhang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China
| | - Georgia Zarkada
- Department of Cellular and Molecular Physiology, Cardiovascular Research Center, Yale School of Medicine, Yale University, New Haven, CT, United States
| | - Sanjun Yi
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China
| | - Anne Eichmann
- Department of Cellular and Molecular Physiology, Cardiovascular Research Center, Yale School of Medicine, Yale University, New Haven, CT, United States.,INSERM U970, Paris Cardiovascular Research Center, Paris, France
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9
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Hautefort A, Pfenniger A, Kwak BR. Endothelial connexins in vascular function. VASCULAR BIOLOGY 2019; 1:H117-H124. [PMID: 32923963 PMCID: PMC7439941 DOI: 10.1530/vb-19-0015] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/28/2019] [Accepted: 11/07/2019] [Indexed: 12/22/2022]
Abstract
Gap junctions are essential for intercellular crosstalk in blood and lymphatic vasculature. These clusters of intercellular channels ensure direct communication among endothelial cells and between endothelial and smooth muscle cells, and the synchronization of their behavior along the vascular tree. Gap junction channels are formed by connexins; six connexins form a connexon or hemichannel and the docking of two connexons result in a full gap junction channel allowing for the exchange of ions and small metabolites between neighboring cells. Recent evidence indicates that the intracellular domains of connexins may also function as an interaction platform (interactome) for other proteins, thereby regulating their function. Interestingly, fragments of Cx proteins generated by alternative internal translation were recently described, although their functions in the vascular wall remain to be uncovered. Variations in connexin expression are observed along different types of blood and lymphatic vessels; the most commonly found endothelial connexins are Cx37, Cx40, Cx43 and Cx47. Physiological studies on connexin-knockout mice demonstrated the essential roles of these channel-forming proteins in the coordination of vasomotor activity, endothelial permeability and inflammation, angiogenesis and in the maintenance of fluid balance in the body.
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Affiliation(s)
- Aurélie Hautefort
- Department of Pathology and Immunology, University of Geneva, Geneva, Switzerland
| | - Anna Pfenniger
- Department of Pathology and Immunology, University of Geneva, Geneva, Switzerland.,Department of Medical Specializations - Cardiology, University of Geneva, Geneva, Switzerland
| | - Brenda R Kwak
- Department of Pathology and Immunology, University of Geneva, Geneva, Switzerland.,Department of Medical Specializations - Cardiology, University of Geneva, Geneva, Switzerland
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10
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Abstract
The systemic circulation depends upon a highly organized, hierarchal blood vascular network that requires the successful specification of arterial and venous endothelial cells during development. This process is driven by a cascade of signaling events (including Hedgehog, vascular endothelial growth factor (VEGF), Notch, connexin (Cx), transforming growth factor-beta (TGF- β), and COUP transcription factor 2 (COUP-TFII)) to influence endothelial cell cycle status and expression of arterial or venous genes and is further regulated by hemodynamic flow. Failure of endothelial cells to properly undergo arteriovenous specification may contribute to vascular malformation and dysfunction, such as in hereditary hemorrhagic telangiectasia (HHT) and capillary malformation-arteriovenous malformation (CM-AVM) where abnormal vessel structures, such as large shunts lacking clear arteriovenous identity and function, form and compromise peripheral blood flow. This review provides an overview of recent findings in the field of arteriovenous specification and highlights key regulators of this process.
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Affiliation(s)
- Jennifer Fang
- Department of Molecular Biology and Biochemistry, School of Biological Sciences, University of California, Irvine, Irvine, CA, 92697, USA
| | - Karen Hirschi
- 2Departments of Medicine, Genetics, and Biomedical Engineering, Yale Cardiovascular Research Center, Yale Stem Cell Center, Yale University School of Medicine, 333 Cedar Street, New Haven, CT, 06520, USA
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11
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Papaneophytou CP, Georgiou E, Karaiskos C, Sargiannidou I, Markoullis K, Freidin MM, Abrams CK, Kleopa KA. Regulatory role of oligodendrocyte gap junctions in inflammatory demyelination. Glia 2018; 66:2589-2603. [PMID: 30325069 PMCID: PMC6519212 DOI: 10.1002/glia.23513] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2018] [Revised: 06/20/2018] [Accepted: 06/25/2018] [Indexed: 12/27/2022]
Abstract
Gap junctions (GJs) coupling oligodendrocytes to astrocytes and to other oligodendrocytes are formed mainly by connexin47 (Cx47) and a smaller portion by connexin32 (Cx32). Mutations in both connexins cause inherited demyelinating disorders, but their expression is also disrupted in multiple sclerosis (MS). To clarify whether the loss of either Cx47 or Cx32 could modify the outcome of inflammation and myelin loss, we induced experimental autoimmune encephalomyelitis (EAE) in fully backcrossed Cx32 knockout (KO) and Cx47KO mice and compared their outcome with wild type (WT, C57BI/6 N) mice. Cx47KO EAE mice developed the most severe phenotype assessed by clinical scores and behavioral testing, followed by Cx32KO and WT mice. Cx47KO more than Cx32KO EAE mice developed more microglial activation, myelin, and axonal loss than did WT mice. Oligodendrocyte apoptosis and precursor proliferation was also higher in Cx47KO than in Cx32KO or WT EAE mice. Similarly, blood-spinal cord barrier (BSCB) disruption and inflammatory infiltrates of macrophages, T- and B-cells were more severe in Cx47KO than either Cx32KO or WT EAE groups. Finally, expression profiling revealed that several proinflammatory cytokines were higher at the peak of inflammation in the Cx47KO mice and persisted at later stages of EAE in contrast to reduction of their levels in WT EAE mice. Thus, loss of oligodendrocyte GJs aggravates BSCB disruption and inflammatory myelin loss, likely due to dysregulation of proinflammatory cytokines. This mechanism may play an important role in MS brain with reduced connexin expression, as well as in patients with inherited mutations in oligodendrocyte connexins and secondary inflammation.
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MESH Headings
- Animals
- Apoptosis/genetics
- Astrocytes/metabolism
- Astrocytes/pathology
- Blood-Brain Barrier/drug effects
- Blood-Brain Barrier/physiopathology
- Calcium-Binding Proteins/metabolism
- Cell Proliferation/genetics
- Connexins/genetics
- Connexins/metabolism
- Cytokines/metabolism
- Disease Models, Animal
- Encephalomyelitis, Autoimmune, Experimental/chemically induced
- Encephalomyelitis, Autoimmune, Experimental/genetics
- Encephalomyelitis, Autoimmune, Experimental/pathology
- Encephalomyelitis, Autoimmune, Experimental/physiopathology
- Freund's Adjuvant/toxicity
- Gap Junctions/metabolism
- Gap Junctions/pathology
- Gene Expression Regulation/drug effects
- Gene Expression Regulation/genetics
- Gene Expression Regulation/physiology
- Hand Strength/physiology
- Macrophages/pathology
- Mice
- Mice, Inbred C57BL
- Microfilament Proteins/metabolism
- Motor Activity/drug effects
- Motor Activity/genetics
- Myelin-Oligodendrocyte Glycoprotein/toxicity
- Oligodendroglia/metabolism
- Oligodendroglia/pathology
- Peptide Fragments/toxicity
- Gap Junction beta-1 Protein
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Affiliation(s)
- Christos P. Papaneophytou
- Neuroscience LaboratoryThe Cyprus Institute of Neurology and Genetics and Cyprus School of Molecular MedicineNicosiaCyprus
- Department of Life and Health Sciences, School of Sciences and EngineeringUniversity of NicosiaNicosiaCyprus
| | - Elena Georgiou
- Neuroscience LaboratoryThe Cyprus Institute of Neurology and Genetics and Cyprus School of Molecular MedicineNicosiaCyprus
| | - Christos Karaiskos
- Neuroscience LaboratoryThe Cyprus Institute of Neurology and Genetics and Cyprus School of Molecular MedicineNicosiaCyprus
| | - Irene Sargiannidou
- Neuroscience LaboratoryThe Cyprus Institute of Neurology and Genetics and Cyprus School of Molecular MedicineNicosiaCyprus
| | - Kyriaki Markoullis
- Neuroscience LaboratoryThe Cyprus Institute of Neurology and Genetics and Cyprus School of Molecular MedicineNicosiaCyprus
| | - Mona M. Freidin
- Department of Neurology and RehabilitationUniversity of Illinois ChicagoChicagoIllinois
| | - Charles K. Abrams
- Department of Neurology and RehabilitationUniversity of Illinois ChicagoChicagoIllinois
| | - Kleopas A. Kleopa
- Neuroscience LaboratoryThe Cyprus Institute of Neurology and Genetics and Cyprus School of Molecular MedicineNicosiaCyprus
- Neurology Clinics, The Cyprus Institute of Neurology and Genetics and Cyprus School of Molecular MedicineNicosiaCyprus
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12
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Castorena-Gonzalez JA, Zawieja SD, Li M, Srinivasan RS, Simon AM, de Wit C, de la Torre R, Martinez-Lemus LA, Hennig GW, Davis MJ. Mechanisms of Connexin-Related Lymphedema. Circ Res 2018; 123:964-985. [PMID: 30355030 PMCID: PMC6771293 DOI: 10.1161/circresaha.117.312576] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
RATIONALE Mutations in GJC2 and GJA1, encoding Cxs (connexins) 47 and 43, respectively, are linked to lymphedema, but the underlying mechanisms are unknown. Because efficient lymph transport relies on the coordinated contractions of lymphatic muscle cells (LMCs) and their electrical coupling through Cxs, Cx-related lymphedema is proposed to result from dyssynchronous contractions of lymphatic vessels. OBJECTIVE To determine which Cx isoforms in LMCs and lymphatic endothelial cells are required for the entrainment of lymphatic contraction waves and efficient lymph transport. METHODS AND RESULTS We developed novel methods to quantify the spatiotemporal entrainment of lymphatic contraction waves and used optogenetic techniques to analyze calcium signaling within and between the LMC and the lymphatic endothelial cell layers. Genetic deletion of the major lymphatic endothelial cell Cxs (Cx43, Cx47, or Cx37) revealed that none were necessary for the synchronization of the global calcium events that triggered propagating contraction waves. We identified Cx45 in human and mouse LMCs as the critical Cx mediating the conduction of pacemaking signals and entrained contractions. Smooth muscle-specific Cx45 deficiency resulted in 10- to 18-fold reduction in conduction speed, partial-to-severe loss of contractile coordination, and impaired lymph pump function ex vivo and in vivo. Cx45 deficiency resulted in profound inhibition of lymph transport in vivo, but only under an imposed gravitational load. CONCLUSIONS Our results (1) identify Cx45 as the Cx isoform mediating the entrainment of the contraction waves in LMCs; (2) show that major endothelial Cxs are dispensable for the entrainment of contractions; (3) reveal a lack of coupling between lymphatic endothelial cells and LMCs, in contrast to arterioles; (4) point to lymphatic valve defects, rather than contraction dyssynchrony, as the mechanism underlying GJC2- or GJA1-related lymphedema; and (5) show that a gravitational load exacerbates lymphatic contractile defects in the intact mouse hindlimb, which is likely critical for the development of lymphedema in the adult mouse.
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Affiliation(s)
| | - Scott D. Zawieja
- Dept. of Medical Pharmacology and Physiology and University of Missouri School of Medicine
| | - Min Li
- Dept. of Medical Pharmacology and Physiology and University of Missouri School of Medicine
| | - R. Sathish Srinivasan
- Cardiovascular Biology Research Program, Oklahoma Medical Research Foundation, Oklahoma City OK
| | | | - Cor de Wit
- Institute of Physiology, University of Luebeck, Luebeck Germany
| | | | - Luis A. Martinez-Lemus
- Dept. of Medical Pharmacology and Physiology and University of Missouri School of Medicine
| | | | - Michael J. Davis
- Dept. of Medical Pharmacology and Physiology and University of Missouri School of Medicine
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13
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Function of Connexins in the Interaction between Glial and Vascular Cells in the Central Nervous System and Related Neurological Diseases. Neural Plast 2018; 2018:6323901. [PMID: 29983707 PMCID: PMC6015683 DOI: 10.1155/2018/6323901] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2018] [Revised: 05/06/2018] [Accepted: 05/14/2018] [Indexed: 02/05/2023] Open
Abstract
Neuronal signaling together with synapse activity in the central nervous system requires a precisely regulated microenvironment. Recently, the blood-brain barrier is considered as a “neuro-glia-vascular unit,” a structural and functional compound composed of capillary endothelial cells, glial cells, pericytes, and neurons, which plays a pivotal role in maintaining the balance of the microenvironment in and out of the brain. Tight junctions and adherens junctions, which function as barriers of the blood-brain barrier, are two well-known kinds in the endothelial cell junctions. In this review, we focus on the less-concerned contribution of gap junction proteins, connexins in blood-brain barrier integrity under physio-/pathology conditions. In the neuro-glia-vascular unit, connexins are expressed in the capillary endothelial cells and prominent in astrocyte endfeet around and associated with maturation and function of the blood-brain barrier through a unique signaling pathway and an interaction with tight junction proteins. Connexin hemichannels and connexin gap junction channels contribute to the physiological or pathological progress of the blood-brain barrier; in addition, the interaction with other cell-cell-adhesive proteins is also associated with the maintenance of the blood-brain barrier. Lastly, we explore the connexins and connexin channels involved in the blood-brain barrier in neurological diseases and any programme for drug discovery or delivery to target or avoid the blood-brain barrier.
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14
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Molica F, Figueroa XF, Kwak BR, Isakson BE, Gibbins JM. Connexins and Pannexins in Vascular Function and Disease. Int J Mol Sci 2018; 19:ijms19061663. [PMID: 29874791 PMCID: PMC6032213 DOI: 10.3390/ijms19061663] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2018] [Revised: 05/28/2018] [Accepted: 05/31/2018] [Indexed: 12/24/2022] Open
Abstract
Connexins (Cxs) and pannexins (Panxs) are ubiquitous membrane channel forming proteins that are critically involved in many aspects of vascular physiology and pathology. The permeation of ions and small metabolites through Panx channels, Cx hemichannels and gap junction channels confers a crucial role to these proteins in intercellular communication and in maintaining tissue homeostasis. This review provides an overview of current knowledge with respect to the pathophysiological role of these channels in large arteries, the microcirculation, veins, the lymphatic system and platelet function. The essential nature of these membrane proteins in vascular homeostasis is further emphasized by the pathologies that are linked to mutations and polymorphisms in Cx and Panx genes.
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Affiliation(s)
- Filippo Molica
- Department of Pathology and Immunology, University of Geneva, CH-1211 Geneva, Switzerland.
| | - Xavier F Figueroa
- Departamento de Fisiología, Faculdad de Ciencias Biológicas, Pontifica Universidad Católica de Chile, Santiago 8330025, Chile.
| | - Brenda R Kwak
- Department of Pathology and Immunology, University of Geneva, CH-1211 Geneva, Switzerland.
| | - Brant E Isakson
- Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, VA 22908, USA.
- Department of Molecular Physiology and Biophysics, University of Virginia School of Medicine, Charlottesville, VA 22908, USA.
| | - Jonathan M Gibbins
- Institute for Cardiovascular & Metabolic Research, School of Biological Sciences, Harborne Building, University of Reading, Reading RG6 6AS, UK.
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15
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Ruez R, Dubrot J, Zoso A, Bacchetta M, Molica F, Hugues S, Kwak BR, Chanson M. Dendritic Cell Migration Toward CCL21 Gradient Requires Functional Cx43. Front Physiol 2018; 9:288. [PMID: 29636699 PMCID: PMC5880903 DOI: 10.3389/fphys.2018.00288] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2018] [Accepted: 03/12/2018] [Indexed: 12/17/2022] Open
Abstract
Dendritic cells (DCs) travel through lymphatic vessels to transport antigens and present them to T cells in lymph nodes. DCs move directionally toward lymphatics by virtue of their CCR7 and a CCL21 chemotactic gradient. We evaluated in vivo and in bone marrow-derived dendritic cells (BMDCs) whether the gap junction protein Cx43 contributes to CCL21/CCR7-dependent DC migration in wild-type (WT) mice, heterozygous (Cx43+/−) mice and mice expressing a truncated form of Cx43 lacking its regulatory C-terminus (Cx43K258/−). In a model of flank skin inflammation, we found that the recruitment of myeloid DCs (mDCs) to skin draining lymph nodes was reduced in Cx43K258/− mice as compared to WT and Cx43+/− mice. In addition, the migration of Cx43K258/− BMDCs toward CCL21 was abolished in an in vitro chemotactic assay while it was only reduced in Cx43+/− cells. Both mutant genotypes showed defects in the directionality of BMDC migration as compared to WT BMDCs. No difference was found between the three populations of BMDCs in terms of expression of surface markers (CD11c, CD86, CD80, CD40, MHC-II, and CCR7) after differentiation and TLR activation. Finally, examination of the CCR7-induced signaling pathways in BMDCs revealed normal receptor-induced mobilization of intracellular Ca2+. These results demonstrate that full expression of an intact Cx43 is critical to the directionality and rate of DC migration, which may be amenable to regulation of the immune response.
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Affiliation(s)
- Richard Ruez
- Department of Pediatrics, Cell Physiology, and Metabolism, Geneva University Hospitals, University of Geneva, Geneva, Switzerland
| | - Juan Dubrot
- Department of Pathology and Immunology, University of Geneva, Geneva, Switzerland
| | - Alice Zoso
- Department of Pediatrics, Cell Physiology, and Metabolism, Geneva University Hospitals, University of Geneva, Geneva, Switzerland
| | - Marc Bacchetta
- Department of Pediatrics, Cell Physiology, and Metabolism, Geneva University Hospitals, University of Geneva, Geneva, Switzerland
| | - Filippo Molica
- Department of Pathology and Immunology, University of Geneva, Geneva, Switzerland
| | - Stéphanie Hugues
- Department of Pathology and Immunology, University of Geneva, Geneva, Switzerland
| | - Brenda R Kwak
- Department of Pathology and Immunology, University of Geneva, Geneva, Switzerland
| | - Marc Chanson
- Department of Pediatrics, Cell Physiology, and Metabolism, Geneva University Hospitals, University of Geneva, Geneva, Switzerland
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16
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The Role of Gap Junction-Mediated Endothelial Cell-Cell Interaction in the Crosstalk between Inflammation and Blood Coagulation. Int J Mol Sci 2017; 18:ijms18112254. [PMID: 29077057 PMCID: PMC5713224 DOI: 10.3390/ijms18112254] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2017] [Revised: 10/21/2017] [Accepted: 10/24/2017] [Indexed: 12/29/2022] Open
Abstract
Endothelial cells (ECs) play a pivotal role in the crosstalk between blood coagulation and inflammation. Endothelial cellular dysfunction underlies the development of vascular inflammatory diseases. Recent studies have revealed that aberrant gap junctions (GJs) and connexin (Cx) hemichannels participate in the progression of cardiovascular diseases such as cardiac infarction, hypertension and atherosclerosis. ECs can communicate with adjacent ECs, vascular smooth muscle cells, leukocytes and platelets via GJs and Cx channels. ECs dynamically regulate the expression of numerous Cxs, as well as GJ functionality, in the context of inflammation. Alterations to either result in various side effects across a wide range of vascular functions. Here, we review the roles of endothelial GJs and Cx channels in vascular inflammation, blood coagulation and leukocyte adhesion. In addition, we discuss the relevant molecular mechanisms that endothelial GJs and Cx channels regulate, both the endothelial functions and mechanical properties of ECs. A better understanding of these processes promises the possibility of pharmacological treatments for vascular pathogenesis.
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