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Roy S, Kim D. Retinal capillary basement membrane thickening: Role in the pathogenesis of diabetic retinopathy. Prog Retin Eye Res 2020; 82:100903. [PMID: 32950677 DOI: 10.1016/j.preteyeres.2020.100903] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Revised: 09/08/2020] [Accepted: 09/15/2020] [Indexed: 02/07/2023]
Abstract
Vascular basement membrane (BM) thickening has been hailed over half a century as the most prominent histological lesion in diabetic microangiopathy, and represents an early ultrastructural change in diabetic retinopathy (DR). Although vascular complications of DR have been clinically well established, specific cellular and molecular mechanisms underlying dysfunction of small vessels are not well understood. In DR, small vessels develop insidiously as BM thickening occurs. Studies examining high resolution imaging data have established BM thickening as one of the foremost structural abnormalities of retinal capillaries. This fundamental structural change develops, at least in part, from excess accumulation of BM components. Although BM thickening is closely associated with the development of DR, its contributory role in the pathogenesis of DR is coming to light recently. DR develops over several years before clinical manifestations appear, and it is during this clinically silent period that hyperglycemia induces excess synthesis of BM components, contributes to vascular BM thickening, and promotes structural and functional lesions including cell death and vascular leakage in the diabetic retina. Studies using animal models show promising results in preventing BM thickening with subsequent beneficial effects. Several gene regulatory approaches are being developed to prevent excess synthesis of vascular BM components in an effort to reduce BM thickening. This review highlights current understanding of capillary BM thickening development, role of BM thickening in retinal vascular lesions, and strategies for preventing vascular BM thickening as a potential therapeutic strategy in alleviating characteristic lesions associated with DR.
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Affiliation(s)
- Sayon Roy
- Boston University School of Medicine, Boston, MA, USA.
| | - Dongjoon Kim
- Boston University School of Medicine, Boston, MA, USA
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2
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Schadzek P, Hermes D, Stahl Y, Dilger N, Ngezahayo A. Concatenation of Human Connexin26 (hCx26) and Human Connexin46 (hCx46) for the Analysis of Heteromeric Gap Junction Hemichannels and Heterotypic Gap Junction Channels. Int J Mol Sci 2018; 19:E2742. [PMID: 30217016 PMCID: PMC6163895 DOI: 10.3390/ijms19092742] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2018] [Revised: 09/10/2018] [Accepted: 09/11/2018] [Indexed: 12/16/2022] Open
Abstract
Gap junction channels and hemichannels formed by concatenated connexins were analyzed. Monomeric (hCx26, hCx46), homodimeric (hCx46-hCx46, hCx26-hCx26), and heterodimeric (hCx26-hCx46, hCx46-hCx26) constructs, coupled to GFP, were expressed in HeLa cells. Confocal microscopy showed that the tandems formed gap junction plaques with a reduced plaque area compared to monomeric hCx26 or hCx46. Dye transfer experiments showed that concatenation allows metabolic transfer. Expressed in Xenopus oocytes, the inside-out patch-clamp configuration showed single channels with a conductance of about 46 pS and 39 pS for hemichannels composed of hCx46 and hCx26 monomers, respectively, when chloride was replaced by gluconate on both membrane sides. The conductance was reduced for hCx46-hCx46 and hCx26-hCx26 homodimers, probably due to the concatenation. Heteromerized hemichannels, depending on the connexin-order, were characterized by substates at 26 pS and 16 pS for hCx46-hCx26 and 31 pS and 20 pS for hCx26-hCx46. Because of the linker between the connexins, the properties of the formed hemichannels and gap junction channels (e.g., single channel conductance) may not represent the properties of hetero-oligomerized channels. However, should the removal of the linker be successful, this method could be used to analyze the electrical and metabolic selectivity of such channels and the physiological consequences for a tissue.
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Affiliation(s)
- Patrik Schadzek
- Institut für Biophysik, Leibniz Universität Hannover, Herrenhäuser Straße 2, 30419 Hannover, Germany.
| | - Doris Hermes
- Institut für Biophysik, Leibniz Universität Hannover, Herrenhäuser Straße 2, 30419 Hannover, Germany.
- Department of Clinical Neurophysiology, University of Göttingen, Robert-Koch Str. 40, D-37075 Göttingen, Germany.
| | - Yannick Stahl
- Institut für Biophysik, Leibniz Universität Hannover, Herrenhäuser Straße 2, 30419 Hannover, Germany.
| | - Nadine Dilger
- Institut für Biophysik, Leibniz Universität Hannover, Herrenhäuser Straße 2, 30419 Hannover, Germany.
| | - Anaclet Ngezahayo
- Institut für Biophysik, Leibniz Universität Hannover, Herrenhäuser Straße 2, 30419 Hannover, Germany.
- Zentrum für Systemische Neurowissenschaften Stiftung Tierärztliche Hochschule Hannover, Bünteweg 2, 30559 Hannover, Germany.
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Cotter ML, Boitano S, Vagner J, Burt JM. Lipidated connexin mimetic peptides potently inhibit gap junction-mediated Ca 2+-wave propagation. Am J Physiol Cell Physiol 2018; 315:C141-C154. [PMID: 29631365 DOI: 10.1152/ajpcell.00156.2017] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Connexin (Cx) mimetic peptides (e.g., Gap27: SRPTEKTIFII; Peptide5: VDCFLSRPTEKT) reversibly inhibit hemichannel (HCh) and gap junction channel (GJCh) function in a concentration- and time-dependent manner (HCh: ~5 µM, <1 h; GJCh: ~100 µM, > 1 h). We hypothesized that addition of a hexadecyl tail to SRPTEKT (SRPTEKT- Hdc) would improve its ability to concentrate in the plasma membrane and consequently increase its inhibitory efficacy. We show that SRPTEKT- Hdc inhibited intercellular Ca2+-wave propagation in Cx43-expressing MDCK and rabbit tracheal epithelial cells in a time (61-75 min)- and concentration (IC50: 66 pM)-dependent manner, a concentration efficacy five orders of magnitude lower than observed for the nonlipidated Gap27. HCh-mediated dye uptake was inhibited by SRPTEKT- Hdc with similar efficacy. Following peptide washout, HCh-mediated dye uptake was restored to control levels, whereas Ca2+-wave propagation was only partially restored. Scrambled and reverse sequence lipidated peptides had no detectable inhibitory effect on Ca2+-wave propagation or dye uptake. Cx43 expression was unchanged by SRPTEKT- Hdc incubation; however, Triton-insoluble Cx43 was reduced by SRPTEKT- Hdc exposure and reversed following washout. In summary, our results show that SRPTEKT- Hdc blocked HCh function and intercellular Ca2+ signaling at concentrations that minimally affected dye coupling. Selective inhibition of intercellular Ca2+ signaling, likely indicative of channel conformation-specific SRPTEKT- Hdc binding, could contribute significantly to the protective effects of these mimetic peptides in settings of injury. Our data also demonstrate that lipidation represents a paradigm for development of highly potent, efficacious, and selective mimetic peptide inhibitors of hemichannel and gap junction channel-mediated signaling.
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Affiliation(s)
- Maura L Cotter
- Department of Physiology, University of Arizona , Tucson, Arizona
| | - Scott Boitano
- Department of Physiology, University of Arizona , Tucson, Arizona.,Asthma and Airway Disease Research Center, University of Arizona , Tucson, Arizona.,Bio5 Collaborative Research Institute, University of Arizona , Tucson, Arizona
| | - Josef Vagner
- Bio5 Collaborative Research Institute, University of Arizona , Tucson, Arizona.,Department of Pharmacology, University of Arizona , Tucson, Arizona
| | - Janis M Burt
- Department of Physiology, University of Arizona , Tucson, Arizona
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Droguett K, Rios M, Carreño DV, Navarrete C, Fuentes C, Villalón M, Barrera NP. An autocrine ATP release mechanism regulates basal ciliary activity in airway epithelium. J Physiol 2017; 595:4755-4767. [PMID: 28422293 PMCID: PMC5509870 DOI: 10.1113/jp273996] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2016] [Accepted: 04/10/2017] [Indexed: 01/07/2023] Open
Abstract
KEY POINTS Extracellular ATP, in association with [Ca2+ ]i regulation, is required to maintain basal ciliary beat frequency. Increasing extracellular ATP levels increases ciliary beating in airway epithelial cells, maintaining a sustained response by inducing the release of additional ATP. Extracellular ATP levels in the millimolar range, previously associated with pathophysiological conditions of the airway epithelium, produce a transient arrest of ciliary activity. The regulation of ciliary beat frequency is dependent on ATP release by hemichannels (connexin/pannexin) and P2X receptor activation, the blockage of which may even stop ciliary movement. The force exerted by cilia, measured by atomic force microscopy, is reduced following extracellular ATP hydrolysis. This result complements the current understanding of the ciliary beating regulatory mechanism, with special relevance to inflammatory diseases of the airway epithelium that affect mucociliary clearance. ABSTRACT Extracellular nucleotides, including ATP, are locally released by the airway epithelium and stimulate ciliary activity in a [Ca2+ ]i -dependent manner after mechanical stimulation of ciliated cells. However, it is unclear whether the ATP released is involved in regulating basal ciliary activity and mediating changes in ciliary activity in response to chemical stimulation. In the present study, we evaluated ciliary beat frequency (CBF) and ciliary beating forces in primary cultures from mouse tracheal epithelium, using videomicroscopy and atomic force microscopy (AFM), respectively. Extracellular ATP levels and [Ca2+ ]i were measured by luminometric and fluorimetric assays, respectively. Uptake of ethidium bromide was measured to evaluate hemichannel functionality. We show that hydrolysis of constitutive extracellular ATP levels with apyrase (50 U ml-1 ) reduced basal CBF by 45% and ciliary force by 67%. The apyrase effect on CBF was potentiated by carbenoxolone, a hemichannel inhibitor, and oxidized ATP, an antagonist used to block P2X7 receptors, which reduced basal CBF by 85%. Additionally, increasing extracellular ATP levels (0.1-100 μm) increased CBF, maintaining a sustained response that was suppressed in the presence of carbenoxolone. We also show that high levels of ATP (1 mm), associated with inflammatory conditions, lowered basal CBF by reducing [Ca2+ ]i and hemichannel functionality. In summary, we provide evidence indicating that airway epithelium ATP release is the molecular autocrine mechanism regulating basal ciliary activity and is also the mediator of the ciliary response to chemical stimulation.
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Affiliation(s)
- Karla Droguett
- Department of Physiology, Faculty of Biological SciencesPontificia Universidad Católica de ChileSantiagoChile
| | - Mariana Rios
- Department of Physiology, Faculty of Biological SciencesPontificia Universidad Católica de ChileSantiagoChile
| | - Daniela V. Carreño
- Department of Physiology, Faculty of Biological SciencesPontificia Universidad Católica de ChileSantiagoChile
| | - Camilo Navarrete
- Department of Physiology, Faculty of Biological SciencesPontificia Universidad Católica de ChileSantiagoChile
| | - Christian Fuentes
- Department of Physiology, Faculty of Biological SciencesPontificia Universidad Católica de ChileSantiagoChile
| | - Manuel Villalón
- Department of Physiology, Faculty of Biological SciencesPontificia Universidad Católica de ChileSantiagoChile
| | - Nelson P. Barrera
- Department of Physiology, Faculty of Biological SciencesPontificia Universidad Católica de ChileSantiagoChile
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Manipulating Cx43 expression triggers gene reprogramming events in dermal fibroblasts from oculodentodigital dysplasia patients. Biochem J 2015; 472:55-69. [PMID: 26349540 DOI: 10.1042/bj20150652] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2015] [Accepted: 09/08/2015] [Indexed: 02/06/2023]
Abstract
Oculodentodigital dysplasia (ODDD) is primarily an autosomal dominant disorder linked to over 70 GJA1 gene [connexin43 (Cx43)] mutations. For nearly a decade, our laboratory has been investigating the relationship between Cx43 and ODDD by expressing disease-linked mutants in reference cells, tissue-relevant cell lines, 3D organ cultures and by using genetically modified mouse models of human disease. Although salient features of Cx43 mutants have been revealed, these models do not necessarily reflect the complexity of the human context. To further overcome these limitations, we have acquired dermal fibroblasts from two ODDD-affected individuals harbouring D3N and V216L mutations in Cx43, along with familial controls. Using these ODDD patient dermal fibroblasts, which naturally produce less GJA1 gene product, along with RNAi and RNA activation (RNAa) approaches, we show that manipulating Cx43 expression triggers cellular gene reprogramming. Quantitative RT-PCR, Western blot and immunofluorescent analysis of ODDD patient fibroblasts show unusually high levels of extracellular matrix (ECM)-interacting proteins, including integrin α5β1, matrix metalloproteinases as well as secreted ECM proteins collagen-I and laminin. Cx43 knockdown in familial control cells produces similar effects on ECM expression, whereas Cx43 transcriptional up-regulation using RNAa decreases production of collagen-I. Interestingly, the enhanced levels of ECM-associated proteins in ODDD V216L fibroblasts is not only a consequence of increased ECM gene expression, but also due to an apparent deficit in collagen-I secretion which may further contribute to impaired collagen gel contraction in ODDD fibroblasts. These findings further illuminate the altered function of Cx43 in ODDD-affected individuals and highlight the impact of manipulating Cx43 expression in human cells.
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Roy S, Bae E, Amin S, Kim D. Extracellular matrix, gap junctions, and retinal vascular homeostasis in diabetic retinopathy. Exp Eye Res 2015; 133:58-68. [PMID: 25819455 DOI: 10.1016/j.exer.2014.08.011] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2014] [Revised: 08/19/2014] [Accepted: 08/20/2014] [Indexed: 12/15/2022]
Abstract
The vascular basement membrane (BM) contains extracellular matrix (ECM) proteins that assemble in a highly organized manner to form a supportive substratum for cell attachment facilitating myriad functions that are vital to cell survival and overall retinal homeostasis. The BM provides a microenvironment in which bidirectional signaling through integrins regulates cell attachment, turnover, and functionality. In diabetic retinopathy, the BM undergoes profound structural and functional changes, and recent studies have brought to light the implications of such changes. Thickened vascular BM in the retinal capillaries actively participate in the development and progression of characteristic changes associated with diabetic retinopathy. High glucose (HG)-induced compromised cell-cell communication via gap junctions (GJ) in retinal vascular cells may disrupt homeostasis in the retinal microenvironment. In this review, the role of altered ECM synthesis, compromised GJ activity, and disturbed retinal homeostasis in the development of retinal vascular lesions in diabetic retinopathy are discussed.
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Affiliation(s)
- Sayon Roy
- Department of Medicine, Boston University School of Medicine, Boston, MA, USA; Department of Ophthalmology, Boston University School of Medicine, Boston, MA, USA.
| | - Edward Bae
- Department of Medicine, Boston University School of Medicine, Boston, MA, USA; Department of Ophthalmology, Boston University School of Medicine, Boston, MA, USA
| | - Shruti Amin
- Department of Medicine, Boston University School of Medicine, Boston, MA, USA; Department of Ophthalmology, Boston University School of Medicine, Boston, MA, USA
| | - Dongjoon Kim
- Department of Medicine, Boston University School of Medicine, Boston, MA, USA; Department of Ophthalmology, Boston University School of Medicine, Boston, MA, USA
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7
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Yang H, Borg TK, Schmidt LP, Gao BZ. Laser cell-micropatterned pair of cardiomyocytes: the relationship between basement membrane development and gap junction maturation. Biofabrication 2014; 6:045003. [PMID: 25215627 DOI: 10.1088/1758-5082/6/4/045003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
The basement membrane (BM), a network of laminin and collagen IV, mechanically supports individual cells and directly mediates cell-cell and cell-extracellular matrix (ECM) interactions. For example, the BM network that tightly encloses each cardiomyocyte (CM) mediates the alignment of CMs with collagen I in the ECM. Additionally, the BM-laminin is involved in the formation of gap junctions (GJs), which regulate electrical coupling between two CMs in the myocardium. The role of BM in GJ maturation remains unclear because of the complicated in vivo structures and lack of an ideal in vitro culturing mode. In this study, our laser cell-micropatterning system was used to place two neonatal CMs (NCMs) in contact on an aligned collagen gel (ACG) to study the relationship between GJ maturation and BM development. The results of double immunofluorescence staining and confocal imaging showed that BM-laminin was deposited earlier than the formation of GJs in the intercellular space and that newly expressed connexin 43 clusters were preferentially assembled near the deposited BM structures. Eventually the BM network surrounded the GJs.
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Affiliation(s)
- Huaxiao Yang
- Department of Bioengineering, Clemson University, SC, USA
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8
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Hackley C, Mulholland E, Kim GJ, Newman-Smith E, Smith WC. A transiently expressed connexin is essential for anterior neural plate development in Ciona intestinalis. Development 2012; 140:147-55. [PMID: 23175630 DOI: 10.1242/dev.084681] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
A forward genetic screen in the ascidian Ciona intestinalis identified a mutant line (frimousse) with a profound disruption in neural plate development. In embryos with the frimousse mutation, the anteriormost neural plate cells, which are products of an FGF induction at the blastula and gastrula stages, initially express neural plate-specific genes but fail to maintain the induced state and ultimately default to epidermis. The genetic lesion in the frimousse mutant lies within a connexin gene (cx-11) that is transiently expressed in the developing neural plate in a temporal window corresponding to the period of a-lineage neural induction. Using a genetically encoded calcium indicator we observed multiple calcium transients throughout the developing neural plate in wild-type embryos, but not in mutant embryos. A series of treatments at the gastrula and neurula stages that block the calcium transients, including gap junction inhibition and calcium depletion, were also found to disrupt the development of the anterior neural plate in a similar way to the frimousse mutation. The requirement for cx-11 for anterior neural fate points to a crucial role for intercellular communication via gap junctions, probably through mediation of Ca(2+) transients, in Ciona intestinalis neural induction.
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Affiliation(s)
- Christopher Hackley
- Department of Molecular, Cellular and Developmental Biology, University of California Santa Barbara, Santa Barbara, CA 93106, USA
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9
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Suh HN, Kim MO, Han HJ. Laminin-111 stimulates proliferation of mouse embryonic stem cells through a reduction of gap junctional intercellular communication via RhoA-mediated Cx43 phosphorylation and dissociation of Cx43/ZO-1/drebrin complex. Stem Cells Dev 2012; 21:2058-70. [PMID: 22150760 DOI: 10.1089/scd.2011.0505] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Gap junctions within extracellular matrix (ECM)-defined boundaries ensure synchronous activity between cells destined to become functional mediators that regulate cell behavior. However, the role of ECM in connexin (Cx) function in mouse embryonic stem cells (mESCs) has not been elucidated. Therefore, we examined the role of laminin-111 in the control of Cx43 functions and related signal pathways in mESCs. ECM components (laminin-111, fibronectin, and collagen I) increased Cx43 phosphorylation and decreased Lucifer yellow (Ly) diffusion. In addition, laminin-111 increased the proliferation index through reduction of gap junctional intercellular communication (GJIC), which was confirmed by 18α-glycyrrhetinic acid (18α-GA). Laminin-111 increased phosphorylation of focal adhesion kinase (FAK)/Src and protein kinase C (PKC), which were inhibited by integrin β1 antibody (Ab) and laminin receptor-1 (LR-1) Ab, respectively. In addition, inhibition of both FAK/Src and PKC blocked Cx43 phosphorylation. Laminin-111 increased the Ras homolog gene family, member A (RhoA) activation, which was blocked by FAK/Src and PKC inhibitors, suggesting the existence of parallel pathways that merge at RhoA. Inhibition of RhoA reversed the laminin-111-induced increase of Cx43 phosphorylation and reduction of GJIC. Laminin-111 also stimulated the dissociation of Cx43/ZO-1 complex followed by disruption of Cx43/drebrin and Cx43/F-actin complexes, which were reversed by C3 (RhoA inhibitor). ZO-1 small interfering (si) RNA significantly decreased Ly diffusion. Moreover, laminin-111 decreased Cx43 labeling at the intercellular junction, whereas pretreatment with degradation inhibitors (lysosomal protease inhibitor, chloroquine; proteasome inhibitor, lactacystin) increased Cx43 expression, reversely. In conclusion, laminin-111 stimulated mESC proliferation through a reduction of GJIC via RhoA-mediated Cx43 phosphorylation and Cx43/ZO-1/drebrin complex instability-mediated Cx43 degradation.
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Affiliation(s)
- Han Na Suh
- Department of Veterinary Physiology, College of Veterinary Medicine, Chonnam National University, Gwangju, South Korea
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Ichikawa-Tomikawa N, Ogawa J, Douet V, Xu Z, Kamikubo Y, Sakurai T, Kohsaka S, Chiba H, Hattori N, Yamada Y, Arikawa-Hirasawa E. Laminin α1 is essential for mouse cerebellar development. Matrix Biol 2012; 31:17-28. [PMID: 21983115 PMCID: PMC3259268 DOI: 10.1016/j.matbio.2011.09.002] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2011] [Revised: 09/13/2011] [Accepted: 09/16/2011] [Indexed: 11/25/2022]
Abstract
Laminin α1 (Lama1), which is a subunit of laminin-1 (laminin-111), a heterotrimeric ECM protein, is essential for embryonic development and promotes neurite outgrowth in culture. Because the deletion of Lama1 causes lethality at early embryonic stages in mice, the in vivo role of Lama1 in neural development and functions has not yet been possible to determine. In this study, we generated conditional Lama1 knockout (Lama1(CKO)) mice in the epiblast lineage using Sox2-Cre mice. These Lama1(CKO) mice survived, but displayed behavioral disorders and impaired formation of the cerebellum. Deficiency of Lama1 in the pial basement membrane of the meninges resulted in defects in the conformation of the meninges. During cerebellar development, Lama1 deficiency also caused a decrease in the proliferation and migration of granule cell precursors, disorganization of Bergmann glial fibers and endfeet, and a transient reduction in the activity of Akt. A marked reduction in numbers of dendritic processes in Purkinje cells was observed in Lama1(CKO) mice. Together, these results indicate that Lama1 is required for cerebellar development and functions.
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Affiliation(s)
- Naoki Ichikawa-Tomikawa
- Research Institute for Diseases of Old Age, Juntendo University Graduate School of Medicine, Tokyo, Japan
- Department of Basic Pathology, Fukushima Medical University School of Medicine, Fukushima, Japan
| | - Junko Ogawa
- Research Institute for Diseases of Old Age, Juntendo University Graduate School of Medicine, Tokyo, Japan
- National Institute of Neuroscience, National Center of Neurology and Psychiatry, Tokyo, Japan
| | - Vanessa Douet
- Research Institute for Diseases of Old Age, Juntendo University Graduate School of Medicine, Tokyo, Japan
| | - Zhuo Xu
- Research Institute for Diseases of Old Age, Juntendo University Graduate School of Medicine, Tokyo, Japan
| | - Yuji Kamikubo
- Department of Pharmacology, Juntendo University Graduate School of Medicine, Tokyo, Japan
| | - Takashi Sakurai
- Department of Pharmacology, Juntendo University Graduate School of Medicine, Tokyo, Japan
| | - Shinichi Kohsaka
- National Institute of Neuroscience, National Center of Neurology and Psychiatry, Tokyo, Japan
| | - Hideki Chiba
- Department of Basic Pathology, Fukushima Medical University School of Medicine, Fukushima, Japan
| | - Nobutaka Hattori
- Department of Neurology, Juntendo University Graduate School of Medicine, Tokyo, Japan
| | - Yoshihiko Yamada
- National Institute of Dental and Craniofacial Research, NIH, Bethesda, Maryland, U.S.A
| | - Eri Arikawa-Hirasawa
- Research Institute for Diseases of Old Age, Juntendo University Graduate School of Medicine, Tokyo, Japan
- Department of Neurology, Juntendo University Graduate School of Medicine, Tokyo, Japan
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Regulation of Intercellular Calcium Signaling Through Calcium Interactions with Connexin-Based Channels. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2012; 740:777-94. [DOI: 10.1007/978-94-007-2888-2_34] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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12
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Choi YH, Lee SN, Aoyagi H, Yamasaki Y, Yoo JY, Park B, Shin DM, Yoon HG, Yoon JH. The extracellular signal-regulated kinase mitogen-activated protein kinase/ribosomal S6 protein kinase 1 cascade phosphorylates cAMP response element-binding protein to induce MUC5B gene expression via D-prostanoid receptor signaling. J Biol Chem 2011; 286:34199-214. [PMID: 21832046 DOI: 10.1074/jbc.m111.247684] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Mucus hypersecretion is a prominent feature of respiratory diseases, and MUC5B is a major airway mucin. Mucin gene expression can be affected by inflammatory mediators, including prostaglandin (PG) D(2,) an inflammatory mediator synthesized by hematopoietic PGD synthase (H-PGDS). PGD(2) binds to either D-prostanoid receptor (DP1) or chemoattractant receptor homologous molecule expressed on T-helper type 2 cells (CRTH2). We investigated the mechanisms by which PGD(2) induces MUC5B gene expression in airway epithelial cells. Western blot analysis showed that H-PGDS was highly expressed in nasal polyps. Similar results were obtained for PGD(2) expression. In addition, we could clearly detect the expressions of both H-PGDS and DP1 in nasal epithelial cells but not CRTH2. We demonstrated that PGD(2) increased MUC5B gene expression in normal human nasal epithelial cells as well as in NCI-H292 cells in vitro. S5751, a DP1 antagonist, inhibited PGD(2)-induced MUC5B expression, whereas a CRTH2 antagonist (OC0459) did not. These data suggest that PGD(2) induced MUC5B expression via DP1. Pretreatment with extracellular signal-regulated kinase (ERK) inhibitor (PD98059) blocked both PGD(2)-induced ERK mitogen-activated protein kinase (MAPK) activation and MUC5B expression. Proximity ligation assays showed direct interaction between RSK1 and cAMP response element-binding protein (CREB). Stimulation with PGD(2) caused an increase in intracellular cAMP levels, whereas intracellular Ca(2+) did not have such an effect. PGD(2)-induced MUC5B mRNA levels were regulated by CREB via direct interaction with two cAMP-response element sites (-921/-914 and -900/-893). Finally, we demonstrated that PGD(2) can induce MUC5B overproduction via ERK MAPK/RSK1/CREB signaling and that DP1 receptor may have suppressive effects in controlling MUC5B overproduction in the airway.
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Affiliation(s)
- Yeon Ho Choi
- The Airway Mucus Institute, Yonsei University College of Medicine, Seoul 120-752, Korea
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13
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Abstract
Motile cilia in the airway epithelium are the engine for mucociliary clearance, the mechanism responsible for cleaning the airways from inhaled particles. Human airway epithelial cilia appear to have a slow constitutive rate of beating, driven by inherent and spontaneous dynein ATPase activity. Additionally, cilia can increase their beating frequency by activation of several different control mechanisms. One of these controllers is calcium. Its intracellular concentration is regulated by purinergic and acetylcholine receptors. Besides the rate regulatory effect of calcium on ciliary beat, calcium is also involved in synchronizing the beat among cilia of one single cell as well as between cilia on different cells. This article gives an overview of the complex effects of calcium on the beating of motile cilia in the airways.
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14
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Koval M, Billaud M, Straub AC, Johnstone SR, Zarbock A, Duling BR, Isakson BE. Spontaneous lung dysfunction and fibrosis in mice lacking connexin 40 and endothelial cell connexin 43. THE AMERICAN JOURNAL OF PATHOLOGY 2011; 178:2536-46. [PMID: 21641379 PMCID: PMC3124229 DOI: 10.1016/j.ajpath.2011.02.045] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2010] [Revised: 12/30/2010] [Accepted: 02/01/2011] [Indexed: 12/31/2022]
Abstract
Gap junction proteins (connexins) facilitate intercellular communication and serve several roles in regulation of tissue function and remodeling. To examine the physiologic effects of depleting two prominent endothelial connexins, Cx40 and Cx43, transgenic mice were generated by breeding Cx40-deficient mice (Cx40(-/-)) with a vascular endothelial cell (VEC)-specific Cx43-deficient mouse strain (VEC Cx43(-/-)) to produce double-connexin knockout mice (VEC Cx43(-/-)/Cx40(-/-)). The life span in VEC Cx43(-/-)/Cx40(-/-) mice was dramatically shortened, which correlated with severe spontaneous lung abnormalities as the mice aged including increased fibrosis, aberrant alveolar remodeling, and increased lung fibroblast content. Moreover, VEC Cx43(-/-)/Cx40(-/-) mice exhibited cardiac hypertrophy and hypertension. Because VEC Cx43(-/-)/Cx40(-/-) mice demonstrated phenotypic hallmarks that were remarkably similar to those in mice deficient in caveolin-1, pulmonary caveolin expression was examined. Lungs from VEC Cx43(-/-)/Cx40(-/-) mice demonstrated significantly decreased expression of caveolin-1 and caveolin-2. This suggests that expression of caveolin-1 may be linked to expression of Cx40 and endothelial Cx43. Moreover, the phenotype of caveolin-1(-/-) mice and VEC Cx43(-/-)/Cx40(-/-) mice may arise via a common mechanism.
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Affiliation(s)
- Michael Koval
- Division of Pulmonary, Allergy, and Critical Care Medicine, Department of Medicine, Emory University School of Medicine, Atlanta, Georgia
- Department of Cell Biology, Emory University School of Medicine, Atlanta, Georgia
| | - Marie Billaud
- Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, Virginia
| | - Adam C. Straub
- Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, Virginia
| | - Scott R. Johnstone
- Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, Virginia
| | - Alexander Zarbock
- Department of Anesthesiology and Critical Care Medicine, University of Münster, Münster, Germany
- Max-Planck-Institute of Molecular Biomedicine, Münster, Germany
| | - Brian R. Duling
- Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, Virginia
- Department of Molecular Physiology and Biological Physics, University of Virginia School of Medicine, Charlottesville, Virginia
| | - Brant E. Isakson
- Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, Virginia
- Department of Molecular Physiology and Biological Physics, University of Virginia School of Medicine, Charlottesville, Virginia
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Boitano S, Flynn AN, Schulz SM, Hoffman J, Price TJ, Vagner J. Potent agonists of the protease activated receptor 2 (PAR2). J Med Chem 2011; 54:1308-13. [PMID: 21294569 DOI: 10.1021/jm1013049] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Novel peptidomimetic pharmacophores to PAR(2) were designed based on the known activating peptide SLIGRL-NH(2). A set of 15 analogues was evaluated with a model cell line (16HBE14o-) that highly expresses PAR(2). Cells exposed to the PAR(2) activating peptide with N-terminal 2-furoyl modification (2-furoyl-LIGRLO-NH(2)) initiated increases in intracellular calcium concentration ([Ca(2+)](i) EC(50) = 0.84 μM) and in vitro physiological responses as measured by the xCELLigence real time cell analyzer (RTCA EC(50) = 138 nM). We discovered two selective PAR(2) agonists with comparable potency: compound 1 (2-aminothiazol-4-yl; Ca(2+) EC(50) = 1.77 μM, RTCA EC(50) = 142 nM) and compound 2 (6-aminonicotinyl; Ca(2+) EC(50) = 2.60 μM, RTCA EC(50) = 311 nM). Unlike the previously described agonist, these novel agonists are devoid of the metabolically unstable 2-furoyl modification and thus provide potential advantages for PAR(2) peptide design for in vitro and in vivo studies. The novel compounds described herein also serve as a starting point for structure-activity relationship (SAR) design and are, for the first time, evaluated via a unique high throughput in vitro physiological assay. Together these will lead to discovery of more potent agonists and antagonists of PAR(2).
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Affiliation(s)
- Scott Boitano
- Arizona Respiratory Center and Department of Physiology, University of Arizona, 1501 N Campbell Avenue, Tucson, Arizona 85724, United States
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16
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Chun J, Prince A. Ca2+ signaling in airway epithelial cells facilitates leukocyte recruitment and transepithelial migration. J Leukoc Biol 2009; 86:1135-44. [PMID: 19605699 DOI: 10.1189/jlb.0209072] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
In airway cells, TLR2 stimulation by bacterial products activates Ca2+ fluxes that signal leukocyte recruitment to the lung and facilitates transepithelial migration into the airway lumen. TLR2 is apically displayed on airway cells, where it senses bacterial stimuli. Biochemical and genetic approaches demonstrate that TLR2 ligands stimulate release of Ca2+ from intracellular stores by activating TLR2 phosphorylation by c-Src and recruiting PI3K and PLCgamma to affect Ca2+ release through IP3Rs. This Ca2+ release plays a pivotal role in signaling TLR2-dependent NF-kappaB activation and chemokine expression to recruit PMNs to the lung. In addition, TLR2-initiated Ca2+ release activates Ca2+-dependent proteases, calpains, which cleave the transmembrane proteins occludin and E-cadherin to promote PMN transmigration. This review highlights recent findings that demonstrate a central role for Ca2+ signaling in airway epithelial cells to induce proinflammatory gene transcription and to initiate junctional changes that accommodate transmigration of recruited PMNs.
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Affiliation(s)
- Jarin Chun
- Department of Pharmacology and Pediatrics, College of Physicians & Surgeons, Columbia University, New York, New York 10032, USA
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17
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Leinonen P, Aaltonen V, Koskela S, Lehenkari P, Korkiamäki T, Peltonen J. Impaired Gap Junction Formation and Intercellular Calcium Signaling in Urinary Bladder Cancer Cells can be Improved by Gö6976. ACTA ACUST UNITED AC 2009; 14:125-36. [DOI: 10.1080/15419060701557065] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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18
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Imbeault S, Gauvin LG, Toeg HD, Pettit A, Sorbara CD, Migahed L, DesRoches R, Menzies AS, Nishii K, Paul DL, Simon AM, Bennett SA. The extracellular matrix controls gap junction protein expression and function in postnatal hippocampal neural progenitor cells. BMC Neurosci 2009; 10:13. [PMID: 19236721 PMCID: PMC2655299 DOI: 10.1186/1471-2202-10-13] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2008] [Accepted: 02/24/2009] [Indexed: 11/23/2022] Open
Abstract
Background Gap junction protein and extracellular matrix signalling systems act in concert to influence developmental specification of neural stem and progenitor cells. It is not known how these two signalling systems interact. Here, we examined the role of ECM components in regulating connexin expression and function in postnatal hippocampal progenitor cells. Results We found that Cx26, Cx29, Cx30, Cx37, Cx40, Cx43, Cx45, and Cx47 mRNA and protein but only Cx32 and Cx36 mRNA are detected in distinct neural progenitor cell populations cultured in the absence of exogenous ECM. Multipotential Type 1 cells express Cx26, Cx30, and Cx43 protein. Their Type 2a progeny but not Type 2b and 3 neuronally committed progenitor cells additionally express Cx37, Cx40, and Cx45. Cx29 and Cx47 protein is detected in early oligodendrocyte progenitors and mature oligodendrocytes respectively. Engagement with a laminin substrate markedly increases Cx26 protein expression, decreases Cx40, Cx43, Cx45, and Cx47 protein expression, and alters subcellular localization of Cx30. These changes are associated with decreased neurogenesis. Further, laminin elicits the appearance of Cx32 protein in early oligodendrocyte progenitors and Cx36 protein in immature neurons. These changes impact upon functional connexin-mediated hemichannel activity but not gap junctional intercellular communication. Conclusion Together, these findings demonstrate a new role for extracellular matrix-cell interaction, specifically laminin, in the regulation of intrinsic connexin expression and function in postnatal neural progenitor cells.
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Affiliation(s)
- Sophie Imbeault
- Neural Regeneration Laboratory and Ottawa Institute of Systems Biology, Dept. of Biochemistry, Microbiology, and Immunology, University of Ottawa, ON, Canada.
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Evans WH, Leybaert L. Mimetic peptides as blockers of connexin channel-facilitated intercellular communication. ACTA ACUST UNITED AC 2008; 14:265-73. [PMID: 18392994 DOI: 10.1080/15419060801891034] [Citation(s) in RCA: 114] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
There is a dearth of chemical inhibitors of connexin-mediated intercellular communication. The advent of short "designer" connexin mimetic peptides has provided new tools to inhibit connexin channels quickly and reversibly. This perspective describes the development of mimetic peptides, especially Gap 26 and 27 that are the most popular and correspond to specific sequences in the extracellular loops of connexins 37, 40 and 43. Initially they were used to inhibit gap-junctional coupling in a wide range of mammalian cells and tissues. Currently, they are also being examined as therapeutic agents that accelerate wound healing and in the early treatment of spinal cord injury. The mimetic peptides bind to connexin hemichannels, influencing channel properties as shown by lowering of electrical conductivity and potently blocking the entry of small reporter dyes and the release of ATP by cells. A mechanism is proposed to help explain the dual action of connexin mimetic peptides on connexin hemichannels and gap-junctional coupling.
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Affiliation(s)
- W Howard Evans
- Department of Medical Biochemistry and Immunology, Wales Heart Research Institute Cardiff University Medical School, Heath Park, Cardiff, UK.
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20
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Martin FJ, Prince AS. TLR2 regulates gap junction intercellular communication in airway cells. THE JOURNAL OF IMMUNOLOGY 2008; 180:4986-93. [PMID: 18354224 DOI: 10.4049/jimmunol.180.7.4986] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The innate immune response to inhaled bacteria, such as the opportunist Pseudomonas aeruginosa, is initiated by TLR2 displayed on the apical surface of airway epithelial cells. Activation of TLR2 is accompanied by an immediate Ca(2+) flux that is both necessary and sufficient to stimulate NF-kappaB and MAPK proinflammatory signaling to recruit and activate polymorphonuclear leukocytes in the airway. In human airway cells, gap junction channels were found to provide a regulated conduit for the movement of Ca(2+) from cell to cell. In response to TLR2 stimulation, by either lipid agonists or P. aeruginosa, gap junctions functioned to transiently amplify proinflammatory signaling by communicating Ca(2+) fluxes from stimulated to adjacent, nonstimulated cells thus increasing epithelial CXCL8 production. P. aeruginosa stimulation also induced tyrosine phosphorylation of connexin 43 and association with c-Src, events linked to the closure of these channels. By 4 h postbacterial stimulation, gap junction communication was decreased indicating an autoregulatory control of the connexins. Thus, gap junction channels comprised of connexin 43 and other connexins in airway cells provide a mechanism to coordinate and regulate the epithelial immune response even in the absence of signals from the immune system.
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Affiliation(s)
- Francis J Martin
- Department of Pharmacology, College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA
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21
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Wiszniewski L, Sanz J, Scerri I, Gasparotto E, Dudez T, Lacroix JS, Suter S, Gallati S, Chanson M. Functional expression of connexin30 and connexin31 in the polarized human airway epithelium. Differentiation 2007; 75:382-92. [PMID: 17428265 DOI: 10.1111/j.1432-0436.2007.00157.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Gap junctions are documented in the human airway epithelium but the functional expression and molecular identity of their protein constituents (connexins, Cx) in the polarized epithelium is not known. To address this question, we documented the expression of a family of epithelial Cx (Cx26, Cx30, Cx30.3, Cx31, Cx31.1, Cx32, Cx37, Cx40, and Cx43) in primary human airway epithelial cells (AEC) grown on porous supports. Under submerged conditions, AEC formed a monolayer of airway cells whereas the air-liquid interface induced within 30-60 days AEC differentiation into a polarized epithelium for up to 6-9 months. Maturation of AEC was associated with the down-regulation of Cx26 and Cx43. The well-differentiated airway epithelium exhibited gap junctional communication between ciliated and between ciliated and basal cells. Interestingly, Cx30 was mostly present between ciliated cells whereas Cx31 was found between basal cells. These results are supportive of the establishment of signal-selective gap junctions with maturation of AEC, likely contributing to support airway epithelium function. These results lay the ground for studying the role of Cx-mediated cell-cell communication during repair following AEC injury and exploring Cx-targeted interventions to modulate the healing process.
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Affiliation(s)
- Ludovic Wiszniewski
- Laboratory of Clinical Investigation III, Department of Pediatrics, Geneva University Hospitals, Geneva, Switzerland
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