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Broad Kinase Inhibition Mitigates Early Neuronal Dysfunction in Tauopathy. Int J Mol Sci 2021; 22:ijms22031186. [PMID: 33530349 PMCID: PMC7865413 DOI: 10.3390/ijms22031186] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2020] [Revised: 01/11/2021] [Accepted: 01/13/2021] [Indexed: 12/26/2022] Open
Abstract
Tauopathies are a group of more than twenty known disorders that involve progressive neurodegeneration, cognitive decline and pathological tau accumulation. Current therapeutic strategies provide only limited, late-stage symptomatic treatment. This is partly due to lack of understanding of the molecular mechanisms linking tau and cellular dysfunction, especially during the early stages of disease progression. In this study, we treated early stage tau transgenic mice with a multi-target kinase inhibitor to identify novel substrates that contribute to cognitive impairment and exhibit therapeutic potential. Drug treatment significantly ameliorated brain atrophy and cognitive function as determined by behavioral testing and a sensitive imaging technique called manganese-enhanced magnetic resonance imaging (MEMRI) with quantitative R1 mapping. Surprisingly, these benefits occurred despite unchanged hyperphosphorylated tau levels. To elucidate the mechanism behind these improved cognitive outcomes, we performed quantitative proteomics to determine the altered protein network during this early stage in tauopathy and compare this model with the human Alzheimer’s disease (AD) proteome. We identified a cluster of preserved pathways shared with human tauopathy with striking potential for broad multi-target kinase intervention. We further report high confidence candidate proteins as novel therapeutically relevant targets for the treatment of tauopathy. Proteomics data are available via ProteomeXchange with identifier PXD023562.
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Boengler K, Rohrbach S, Weissmann N, Schulz R. Importance of Cx43 for Right Ventricular Function. Int J Mol Sci 2021; 22:ijms22030987. [PMID: 33498172 PMCID: PMC7863922 DOI: 10.3390/ijms22030987] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Revised: 01/13/2021] [Accepted: 01/18/2021] [Indexed: 11/16/2022] Open
Abstract
In the heart, connexins form gap junctions, hemichannels, and are also present within mitochondria, with connexin 43 (Cx43) being the most prominent connexin in the ventricles. Whereas the role of Cx43 is well established for the healthy and diseased left ventricle, less is known about the importance of Cx43 for the development of right ventricular (RV) dysfunction. The present article focusses on the importance of Cx43 for the developing heart. Furthermore, we discuss the expression and localization of Cx43 in the diseased RV, i.e., in the tetralogy of Fallot and in pulmonary hypertension, in which the RV is affected, and RV hypertrophy and failure occur. We will also introduce other Cx molecules that are expressed in RV and surrounding tissues and have been reported to be involved in RV pathophysiology. Finally, we highlight therapeutic strategies aiming to improve RV function in pulmonary hypertension that are associated with alterations of Cx43 expression and function.
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Cirillo F, Piccoli M, Ghiroldi A, Monasky MM, Rota P, La Rocca P, Tarantino A, D'Imperio S, Signorelli P, Pappone C, Anastasia L. The antithetic role of ceramide and sphingosine-1-phosphate in cardiac dysfunction. J Cell Physiol 2021; 236:4857-4873. [PMID: 33432663 DOI: 10.1002/jcp.30235] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Revised: 12/09/2020] [Accepted: 12/11/2020] [Indexed: 12/27/2022]
Abstract
Cardiovascular diseases (CVDs) are the leading cause of death globally and the number of cardiovascular patients, which is estimated to be over 30 million in 2018, represent a challenging issue for the healthcare systems worldwide. Therefore, the identification of novel molecular targets to develop new treatments is an ongoing challenge for the scientific community. In this context, sphingolipids (SLs) have been progressively recognized as potent bioactive compounds that play crucial roles in the modulation of several key biological processes, such as proliferation, differentiation, and apoptosis. Furthermore, SLs involvement in cardiac physiology and pathophysiology attracted much attention, since these molecules could be crucial in the development of CVDs. Among SLs, ceramide and sphingosine-1-phosphate (S1P) represent the most studied bioactive lipid mediators, which are characterized by opposing activities in the regulation of the fate of cardiac cells. In particular, maintaining the balance of the so-called ceramide/S1P rheostat emerged as an important novel therapeutical target to counteract CVDs. Thus, this review aims at critically summarizing the current knowledge about the antithetic roles of ceramide and S1P in cardiomyocytes dysfunctions, highlighting how the modulation of their metabolism through specific molecules, such as myriocin and FTY720, could represent a novel and interesting therapeutic approach to improve the management of CVDs.
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Affiliation(s)
- Federica Cirillo
- Laboratory of Stem Cells for Tissue Engineering, IRCCS Policlinico San Donato, Milan, Italy
| | - Marco Piccoli
- Laboratory of Stem Cells for Tissue Engineering, IRCCS Policlinico San Donato, Milan, Italy
| | - Andrea Ghiroldi
- Laboratory of Stem Cells for Tissue Engineering, IRCCS Policlinico San Donato, Milan, Italy
| | | | - Paola Rota
- Department of Biomedical, Surgical and Dental Sciences, University of Milan, Milan, Italy
| | - Paolo La Rocca
- Department of Biomedical Sciences for Health, University of Milan, Milan, Italy
| | - Adriana Tarantino
- Laboratory of Stem Cells for Tissue Engineering, IRCCS Policlinico San Donato, Milan, Italy.,Department of Arrhythmology, IRCCS Policlinico San Donato, Milan, Italy
| | - Sara D'Imperio
- Laboratory of Stem Cells for Tissue Engineering, IRCCS Policlinico San Donato, Milan, Italy.,Department of Arrhythmology, IRCCS Policlinico San Donato, Milan, Italy
| | - Paola Signorelli
- Department of Health Sciences, Biochemistry and Molecular Biology Laboratory, University of Milan, Milan, Italy
| | - Carlo Pappone
- Department of Arrhythmology, IRCCS Policlinico San Donato, Milan, Italy.,Faculty of Medicine and Surgery, University of Vita-Salute San Raffaele, Milan, Italy
| | - Luigi Anastasia
- Laboratory of Stem Cells for Tissue Engineering, IRCCS Policlinico San Donato, Milan, Italy.,Faculty of Medicine and Surgery, University of Vita-Salute San Raffaele, Milan, Italy
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54
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Acosta ML, Mat Nor MN, Guo CX, Mugisho OO, Coutinho FP, Rupenthal ID, Green CR. Connexin therapeutics: blocking connexin hemichannel pores is distinct from blocking pannexin channels or gap junctions. Neural Regen Res 2021; 16:482-488. [PMID: 32985469 PMCID: PMC7996017 DOI: 10.4103/1673-5374.290097] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Compounds that block the function of connexin and pannexin protein channels have been suggested to be valuable therapeutics for a range of diseases. Some of these compounds are now in clinical trials, but for many of them, the literature is inconclusive about the molecular effect on the tissue, despite evidence of functional recovery. Blocking the different channel types has distinct physiological and pathological implications and this review describes current knowledge of connexin and pannexin protein channels, their function as channels and possible mechanisms of the channel block effect for the latest therapeutic compounds. We summarize the evidence implicating pannexins and connexins in disease, considering their homeostatic versus pathological roles, their contribution to excesive ATP release linked to disease onset and progression.
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Affiliation(s)
- Monica L Acosta
- School of Optometry and Vision Science; New Zealand National Eye Centre, University of Auckland; Centre for Brain Research, Faculty of Medical and Health Sciences, The University of Auckland; Brain Research New Zealand-Rangahau Roro Aotearoa, Auckland, New Zealand
| | - Mohd N Mat Nor
- School of Optometry and Vision Science, University of Auckland, Auckland, New Zealand; Faculty of Medicine, Universiti Sultan Zainal Abidin, Terengganu, Malaysia
| | - Cindy X Guo
- School of Optometry and Vision Science, University of Auckland, Auckland, New Zealand
| | - Odunayo O Mugisho
- Department of Ophthalmology, University of Auckland; Buchanan Ocular Therapeutics Unit, Department of Ophthalmology; New Zealand National Eye Centre, University of Auckland, Auckland, New Zealand
| | - Frazer P Coutinho
- Department of Ophthalmology, University of Auckland, Auckland, New Zealand
| | - Ilva D Rupenthal
- Department of Ophthalmology, University of Auckland; Buchanan Ocular Therapeutics Unit, Department of Ophthalmology; New Zealand National Eye Centre, University of Auckland, Auckland, New Zealand
| | - Colin R Green
- Department of Ophthalmology; New Zealand National Eye Centre, University of Auckland, Auckland, New Zealand
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55
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Au A, Shao Q, White KK, Lucaciu SA, Esseltine JL, Barr K, Laird DW. Comparative Analysis of Cx31 and Cx43 in Differentiation-Competent Rodent Keratinocytes. Biomolecules 2020; 10:biom10101443. [PMID: 33066499 PMCID: PMC7602205 DOI: 10.3390/biom10101443] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2020] [Revised: 09/30/2020] [Accepted: 10/08/2020] [Indexed: 12/25/2022] Open
Abstract
When considering connexin expression and regulation, the epidermis of the skin is one of the most complex tissues found in mammals even though it largely contains a single cell type, the keratinocyte. In the rodent epidermis, up to 9 connexin family members have been detected at the mRNA level. Many of these connexins are temporally and spatially regulated in coordination with keratinocyte progenitor cell differentiation and migration from the stratum basale to form the stratum spinosum and stratum granulosum layers before finally forming the stratum corneum. Cx43 is the principal connexin found in basal keratinocytes and to a lesser degree found in keratinocytes that have begun to differentiate where Cx26, Cx30 and Cx31 become prevalent. Here we show that the CRISPR-Cas9 ablation of Cx43 reduces overall gap junction coupling in monolayer cultures of rat epidermal keratinocytes (REKs) and dysregulates the differentiation of REKs when grown in organotypic cultures. Natively found in differentiated keratinocytes, Cx31 readily assembles into gap junctions when expressed in REKs where it can extensively co-assemble into the same gap junctions with co-expressed Cx30. Time-lapse imaging indicated that many Cx31 gap junctions are mobile within the plasma membrane undergoing both fusion and fission events. Finally, the persistence of pre-existing Cx31 gap junctions in the presence of the protein trafficking blocker, brefeldin A, is longer than that found for Cx43 gap junctions indicating that it has a distinctly different life expectancy in REKs. Collectively, this study highlights the importance of Cx43 in rodent keratinocyte differentiation and suggests that Cx31 acquires life-cycle properties that are distinct from Cx43.
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Affiliation(s)
- Akina Au
- Department of Physiology and Pharmacology, The University of Western Ontario, London, ON N6A 5C1, Canada; (A.A.); (S.A.L.)
| | - Qing Shao
- Department of Anatomy and Cell Biology, The University of Western Ontario, London, ON N6A 5C1, Canada; (Q.S.); (K.K.W.); (K.B.)
| | - Kyra K. White
- Department of Anatomy and Cell Biology, The University of Western Ontario, London, ON N6A 5C1, Canada; (Q.S.); (K.K.W.); (K.B.)
| | - Sergiu A. Lucaciu
- Department of Physiology and Pharmacology, The University of Western Ontario, London, ON N6A 5C1, Canada; (A.A.); (S.A.L.)
| | - Jessica L. Esseltine
- Division of BioMedical Sciences, Faculty of Medicine, Memorial University of Newfoundland, St. John’s, NL A1B 3V6, Canada;
| | - Kevin Barr
- Department of Anatomy and Cell Biology, The University of Western Ontario, London, ON N6A 5C1, Canada; (Q.S.); (K.K.W.); (K.B.)
| | - Dale W. Laird
- Department of Physiology and Pharmacology, The University of Western Ontario, London, ON N6A 5C1, Canada; (A.A.); (S.A.L.)
- Department of Anatomy and Cell Biology, The University of Western Ontario, London, ON N6A 5C1, Canada; (Q.S.); (K.K.W.); (K.B.)
- Correspondence: ; Tel.: +1-519-661-2111 (ext. 86827)
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56
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Brecker M, Khakhina S, Schubert TJ, Thompson Z, Rubenstein RC. The Probable, Possible, and Novel Functions of ERp29. Front Physiol 2020; 11:574339. [PMID: 33013490 PMCID: PMC7506106 DOI: 10.3389/fphys.2020.574339] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Accepted: 08/14/2020] [Indexed: 12/16/2022] Open
Abstract
The luminal endoplasmic reticulum (ER) protein of 29 kDa (ERp29) is a ubiquitously expressed cellular agent with multiple critical roles. ERp29 regulates the biosynthesis and trafficking of several transmembrane and secretory proteins, including the cystic fibrosis transmembrane conductance regulator (CFTR), the epithelial sodium channel (ENaC), thyroglobulin, connexin 43 hemichannels, and proinsulin. ERp29 is hypothesized to promote ER to cis-Golgi cargo protein transport via COP II machinery through its interactions with the KDEL receptor; this interaction may facilitate the loading of ERp29 clients into COP II vesicles. ERp29 also plays a role in ER stress (ERS) and the unfolded protein response (UPR) and is implicated in oncogenesis. Here, we review the vast array of ERp29’s clients, its role as an ER to Golgi escort protein, and further suggest ERp29 as a potential target for therapies related to diseases of protein misfolding and mistrafficking.
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Affiliation(s)
- Margaret Brecker
- Cystic Fibrosis Center, The Children’s Hospital of Philadelphia, Philadelphia, PA, United States
| | - Svetlana Khakhina
- Cystic Fibrosis Center, The Children’s Hospital of Philadelphia, Philadelphia, PA, United States
| | - Tyler J. Schubert
- Cystic Fibrosis Center, The Children’s Hospital of Philadelphia, Philadelphia, PA, United States
| | - Zachary Thompson
- Cystic Fibrosis Center, The Children’s Hospital of Philadelphia, Philadelphia, PA, United States
| | - Ronald C. Rubenstein
- Cystic Fibrosis Center, The Children’s Hospital of Philadelphia, Philadelphia, PA, United States
- Department of Pediatrics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, United States
- Division of Allergy and Pulmonary Medicine, Department of Pediatrics, Washington University in St. Louis School of Medicine, St. Louis, MO, United States
- *Correspondence: Ronald C. Rubenstein, ;
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Development of a Cx46 Targeting Strategy for Cancer Stem Cells. Cell Rep 2020; 27:1062-1072.e5. [PMID: 31018124 PMCID: PMC6497083 DOI: 10.1016/j.celrep.2019.03.079] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2018] [Revised: 01/21/2019] [Accepted: 03/21/2019] [Indexed: 12/18/2022] Open
Abstract
Gap-junction-mediated cell-cell communication enables tumor cells to synchronize complex processes. We previously found that glioblastoma cancer stem cells (CSCs) express higher levels of the gap junction protein Cx46 compared to non-stem tumor cells (non-CSCs) and that this was necessary and sufficient for CSC maintenance. To understand the mechanism underlying this requirement, we use point mutants to disrupt specific functions of Cx46 and find that Cx46-mediated gap-junction coupling is critical for CSCs. To develop a Cx46 targeting strategy, we screen a clinically relevant small molecule library and identify clofazimine as an inhibitor of Cx46-specific cell-cell communication. Clofazimine attenuates proliferation, self-renewal, and tumor growth and synergizes with temozolomide to induce apoptosis. Although clofazimine does not cross the blood-brain barrier, the combination of clofazimine derivatives optimized for brain penetrance with standard-of-care therapies may target glioblastoma CSCs. Furthermore, these results demonstrate the importance of targeting cell-cell communication as an anti-cancer therapy.
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58
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Taylor SSZ, Jacobsen NL, Pontifex TK, Langlais P, Burt JM. Serine 319 phosphorylation is necessary and sufficient to induce a Cx37 conformation that leads to arrested cell cycling. J Cell Sci 2020; 133:jcs240721. [PMID: 32350069 PMCID: PMC7328134 DOI: 10.1242/jcs.240721] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2019] [Accepted: 04/14/2020] [Indexed: 11/20/2022] Open
Abstract
Connexin 37 (Cx37; protein product of GJA4) expression profoundly suppresses proliferation of rat insulinoma (Rin) cells in a manner dependent on gap junction channel (GJCh) functionality and the presence and phosphorylation status of its C-terminus (CT). In Rin cells, growth is arrested upon induced Cx37 expression and serine 319 (S319) is frequently phosphorylated. Here, we show that preventing phosphorylation at this site (alanine substitution; S319A) relieved Cx37 of its growth-suppressive effect whereas mimicking phosphorylation at this site (aspartate substitution; S319D) enhanced the growth-suppressive properties of Cx37. Like wild-type Cx37 (Cx37-WT), Cx37-S319D GJChs and hemichannels (HChs) preferred the closed state, rarely opening fully, and gated slowly. In contrast, Cx37-S319A channels preferred open states, opened fully and gated rapidly. These data indicate that phosphorylation-dependent conformational differences in Cx37 protein and channel function underlie Cx37-induced growth arrest versus growth-permissive phenotypes. That the closed state of Cx37-WT and Cx37-S319D GJChs and HChs favors growth arrest suggests that rather than specific permeants mediating cell cycle arrest, the closed conformation instead supports interaction of Cx37 with growth regulatory proteins that result in growth arrest.
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Affiliation(s)
| | - Nicole L Jacobsen
- Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, MO 65211, USA
| | - Tasha K Pontifex
- Department of Physiology, University of Arizona, Tucson, AZ 85724, USA
| | - Paul Langlais
- Department of Medicine, University of Arizona, Tucson, AZ 85724, USA
| | - Janis M Burt
- Department of Physiology, University of Arizona, Tucson, AZ 85724, USA
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59
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Plotkin LI, Buvinic S, Balanta-Melo J. In vitro and in vivo studies using non-traditional bisphosphonates. Bone 2020; 134:115301. [PMID: 32112989 PMCID: PMC7138726 DOI: 10.1016/j.bone.2020.115301] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Revised: 02/06/2020] [Accepted: 02/22/2020] [Indexed: 01/26/2023]
Abstract
Non-traditional bisphosphonates, that is, bisphosphonates that do not inhibit osteoclast viability or function, were initially reported in the 1990s by Socrates Papapoulos' group. Originally designed to study the role of the R1 residue of aminobisphosphonates on bisphosphonate affinity for hydroxyapatite, these modified bisphosphonates retained similar affinity for mineralized bone as their parent compounds, but they lacked the potential to inhibit the mevalonate pathway or bone resorption. We found that, similar to classical bisphosphonates, these non-traditional compounds prevented osteoblast and osteocyte apoptosis in vitro through a pathway that requires the expression of the gap junction protein connexin 43, and the activation of the Src/MEK/ERK signaling pathway. Furthermore, one of those compounds named IG9402 (also known as amino-olpadronate or lidadronate), was able to inhibit osteoblast and osteocyte apoptosis, without affecting osteoclast number or bone resorption in vivo in a model of glucocorticoid-induced osteoporosis. IG9402 administration also ameliorated the decrease in bone mass and in bone mechanical properties induced by glucocorticoids. Similarly, IG9402 prevented apoptosis of osteoblastic cells in a model of immobilization due to hindlimb unloading. However, in this case, the bisphosphonate was not able to preserve the bone mass, and only partially prevented the decrease in bone mechanical properties induced by immobilization. The effect of IG9402 administration was also tested in a mouse model of masticatory hypofunction through the induction of masseter muscle atrophy by unilateral injection of botulinum toxin type A (BoNTA). IG9402 partially inhibited the loss of trabecular bone microstructure in the mandibular condyle, but not the decrease in masseter muscle mass induced by BoNTA administration. In summary, these non-traditional bisphosphonates that lack anti-resorptive activity but are able to preserve osteoblast and osteocyte viability could constitute useful tools to study the consequences of preventing apoptosis of osteoblastic cells in animal models. Furthermore, they could be used to treat conditions associated with reduced bone mass and increased bone fragility in which a reduction of bone remodeling is not desirable.
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Affiliation(s)
- Lilian I Plotkin
- Department of Anatomy, Cell Biology & Physiology, Indiana University School of Medicine, Indianapolis, IN, United States of America; Indiana Center for Musculoskeletal Health, Indianapolis, IN, United States of America.
| | - Sonja Buvinic
- Institute for Research in Dental Sciences, Faculty of Dentistry, Universidad de Chile, Santiago, Chile; Center for Exercise, Metabolism and Cancer CEMC2016, Faculty of Medicine, Universidad de Chile, Santiago, Chile
| | - Julián Balanta-Melo
- Institute for Research in Dental Sciences, Faculty of Dentistry, Universidad de Chile, Santiago, Chile; School of Dentistry, Universidad del Valle, Cali, Colombia; Max Planck Weizmann Center for Integrative Archaeology and Anthropology, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
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60
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Giaume C, Naus CC, Sáez JC, Leybaert L. Glial Connexins and Pannexins in the Healthy and Diseased Brain. Physiol Rev 2020; 101:93-145. [PMID: 32326824 DOI: 10.1152/physrev.00043.2018] [Citation(s) in RCA: 75] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Over the past several decades a large amount of data have established that glial cells, the main cell population in the brain, dynamically interact with neurons and thus impact their activity and survival. One typical feature of glia is their marked expression of several connexins, the membrane proteins forming intercellular gap junction channels and hemichannels. Pannexins, which have a tetraspan membrane topology as connexins, are also detected in glial cells. Here, we review the evidence that connexin and pannexin channels are actively involved in dynamic and metabolic neuroglial interactions in physiological as well as in pathological situations. These features of neuroglial interactions open the way to identify novel non-neuronal aspects that allow for a better understanding of behavior and information processing performed by neurons. This will also complement the "neurocentric" view by facilitating the development of glia-targeted therapeutic strategies in brain disease.
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Affiliation(s)
- Christian Giaume
- Collège de France, Center for Interdisciplinary Research in Biology (CIRB)/Centre National de la Recherche Scientifique, Unité Mixte de Recherche 7241/Institut National de la Santé et de la Recherche Médicale U1050, Paris, France; University Pierre et Marie Curie, Paris, France; MEMOLIFE Laboratory of Excellence and Paris Science Lettre Research University, Paris, France; Department of Cellular & Physiological Sciences, Life Sciences Institute, Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada; Departamento de Fisiología, Pontificia Universidad Católica de Chile, Santiago, Chile; Instituo de Neurociencias, Centro Interdisciplinario de Neurociencias, Universidad de Valparaíso, Valparaíso, Chile; Physiology Group, Department of Basic and Applied Medical Sciences, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium
| | - Christian C Naus
- Collège de France, Center for Interdisciplinary Research in Biology (CIRB)/Centre National de la Recherche Scientifique, Unité Mixte de Recherche 7241/Institut National de la Santé et de la Recherche Médicale U1050, Paris, France; University Pierre et Marie Curie, Paris, France; MEMOLIFE Laboratory of Excellence and Paris Science Lettre Research University, Paris, France; Department of Cellular & Physiological Sciences, Life Sciences Institute, Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada; Departamento de Fisiología, Pontificia Universidad Católica de Chile, Santiago, Chile; Instituo de Neurociencias, Centro Interdisciplinario de Neurociencias, Universidad de Valparaíso, Valparaíso, Chile; Physiology Group, Department of Basic and Applied Medical Sciences, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium
| | - Juan C Sáez
- Collège de France, Center for Interdisciplinary Research in Biology (CIRB)/Centre National de la Recherche Scientifique, Unité Mixte de Recherche 7241/Institut National de la Santé et de la Recherche Médicale U1050, Paris, France; University Pierre et Marie Curie, Paris, France; MEMOLIFE Laboratory of Excellence and Paris Science Lettre Research University, Paris, France; Department of Cellular & Physiological Sciences, Life Sciences Institute, Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada; Departamento de Fisiología, Pontificia Universidad Católica de Chile, Santiago, Chile; Instituo de Neurociencias, Centro Interdisciplinario de Neurociencias, Universidad de Valparaíso, Valparaíso, Chile; Physiology Group, Department of Basic and Applied Medical Sciences, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium
| | - Luc Leybaert
- Collège de France, Center for Interdisciplinary Research in Biology (CIRB)/Centre National de la Recherche Scientifique, Unité Mixte de Recherche 7241/Institut National de la Santé et de la Recherche Médicale U1050, Paris, France; University Pierre et Marie Curie, Paris, France; MEMOLIFE Laboratory of Excellence and Paris Science Lettre Research University, Paris, France; Department of Cellular & Physiological Sciences, Life Sciences Institute, Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada; Departamento de Fisiología, Pontificia Universidad Católica de Chile, Santiago, Chile; Instituo de Neurociencias, Centro Interdisciplinario de Neurociencias, Universidad de Valparaíso, Valparaíso, Chile; Physiology Group, Department of Basic and Applied Medical Sciences, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium
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61
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Buruiană A, Florian ȘI, Florian AI, Timiș TL, Mihu CM, Miclăuș M, Oșan S, Hrapșa I, Cataniciu RC, Farcaș M, Șușman S. The Roles of miRNA in Glioblastoma Tumor Cell Communication: Diplomatic and Aggressive Negotiations. Int J Mol Sci 2020; 21:ijms21061950. [PMID: 32178454 PMCID: PMC7139390 DOI: 10.3390/ijms21061950] [Citation(s) in RCA: 62] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Revised: 03/05/2020] [Accepted: 03/06/2020] [Indexed: 02/07/2023] Open
Abstract
Glioblastoma (GBM) consists of a heterogeneous collection of competing cellular clones which communicate with each other and with the tumor microenvironment (TME). MicroRNAs (miRNAs) present various exchange mechanisms: free miRNA, extracellular vesicles (EVs), or gap junctions (GJs). GBM cells transfer miR-4519 and miR-5096 to astrocytes through GJs. Oligodendrocytes located in the invasion front present high levels of miR-219-5p, miR-219-2-3p, and miR-338-3p, all related to their differentiation. There is a reciprocal exchange between GBM cells and endothelial cells (ECs) as miR-5096 promotes angiogenesis after being transferred into ECs, whereas miR-145-5p acts as a tumor suppressor. In glioma stem cells (GSCs), miR-1587 and miR-3620-5p increase the proliferation and miR-1587 inhibits the hormone receptor co-repressor-1 (NCOR1) after EVs transfers. GBM-derived EVs carry miR-21 and miR-451 that are up-taken by microglia and monocytes/macrophages, promoting their proliferation. Macrophages release EVs enriched in miR-21 that are transferred to glioma cells. This bidirectional miR-21 exchange increases STAT3 activity in GBM cells and macrophages, promoting invasion, proliferation, angiogenesis, and resistance to treatment. miR-1238 is upregulated in resistant GBM clones and their EVs, conferring resistance to adjacent cells via the CAV1/EGFR signaling pathway. Decrypting these mechanisms could lead to a better patient stratification and the development of novel target therapies.
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Affiliation(s)
- Andrei Buruiană
- Department of Medical Genetics, Iuliu Hațieganu University of Medicine and Pharmacy, 8 Victor Babes Street, 400012 Cluj-Napoca, Romania; (A.B.); (S.O.); (I.H.); (R.C.C.); (M.F.)
| | - Ștefan Ioan Florian
- Department of Neurosurgery, Iuliu Hațieganu University of Medicine and Pharmacy, 8 Victor Babes Street, 400012 Cluj-Napoca, Romania; (Ș.I.F.); (A.I.F.)
- Department of Neurosurgery, Emergency County Hospital, 3-5 Clinicilor Street, 400006 Cluj-Napoca, Romania
| | - Alexandru Ioan Florian
- Department of Neurosurgery, Iuliu Hațieganu University of Medicine and Pharmacy, 8 Victor Babes Street, 400012 Cluj-Napoca, Romania; (Ș.I.F.); (A.I.F.)
- Department of Neurosurgery, Emergency County Hospital, 3-5 Clinicilor Street, 400006 Cluj-Napoca, Romania
| | - Teodora-Larisa Timiș
- Department of Physiology, Iuliu Hațieganu University of Medicine and Pharmacy, 8 Victor Babes Street, 400012 Cluj-Napoca, Romania;
| | - Carmen Mihaela Mihu
- Department of Morphological Sciences-Histology, Iuliu Hațieganu University of Medicine and Pharmacy, 8 Victor Babes Street, 400012 Cluj-Napoca, Romania;
| | - Maria Miclăuș
- Department of Medical Genetics, Emergency Hospital for Children, 68 Moților Street, 400370 Cluj-Napoca, Romania;
| | - Sergiu Oșan
- Department of Medical Genetics, Iuliu Hațieganu University of Medicine and Pharmacy, 8 Victor Babes Street, 400012 Cluj-Napoca, Romania; (A.B.); (S.O.); (I.H.); (R.C.C.); (M.F.)
| | - Iona Hrapșa
- Department of Medical Genetics, Iuliu Hațieganu University of Medicine and Pharmacy, 8 Victor Babes Street, 400012 Cluj-Napoca, Romania; (A.B.); (S.O.); (I.H.); (R.C.C.); (M.F.)
| | - Radu Constantin Cataniciu
- Department of Medical Genetics, Iuliu Hațieganu University of Medicine and Pharmacy, 8 Victor Babes Street, 400012 Cluj-Napoca, Romania; (A.B.); (S.O.); (I.H.); (R.C.C.); (M.F.)
| | - Marius Farcaș
- Department of Medical Genetics, Iuliu Hațieganu University of Medicine and Pharmacy, 8 Victor Babes Street, 400012 Cluj-Napoca, Romania; (A.B.); (S.O.); (I.H.); (R.C.C.); (M.F.)
- Department of Genetics, IMOGEN Research Center, Louis Pasteur Street, 400349 Cluj-Napoca, Romania
| | - Sergiu Șușman
- Department of Morphological Sciences-Histology, Iuliu Hațieganu University of Medicine and Pharmacy, 8 Victor Babes Street, 400012 Cluj-Napoca, Romania;
- Department of Pathology, IMOGEN Research Center, Louis Pasteur Street, 400349 Cluj-Napoca, Romania
- Correspondence:
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Guo J, Yoshida K, Ikegame M, Okamura H. Quorum sensing molecule N-(3-oxododecanoyl)-l-homoserine lactone: An all-rounder in mammalian cell modification. J Oral Biosci 2020; 62:16-29. [DOI: 10.1016/j.job.2020.01.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2019] [Revised: 01/09/2020] [Accepted: 01/14/2020] [Indexed: 01/17/2023]
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Riquelme MA, Cardenas ER, Xu H, Jiang JX. The Role of Connexin Channels in the Response of Mechanical Loading and Unloading of Bone. Int J Mol Sci 2020; 21:ijms21031146. [PMID: 32050469 PMCID: PMC7038207 DOI: 10.3390/ijms21031146] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2020] [Revised: 01/31/2020] [Accepted: 02/04/2020] [Indexed: 12/13/2022] Open
Abstract
The skeleton adapts to mechanical loading to promote bone formation and remodeling. While most bone cells are involved in mechanosensing, it is well accepted that osteocytes are the principal mechanosensory cells. The osteocyte cell body and processes are surrounded by a fluid-filled space, forming an extensive lacuno-canalicular network. The flow of interstitial fluid is a major stress-related factor that transmits mechanical stimulation to bone cells. The long dendritic processes of osteocytes form a gap junction channel network connecting not only neighboring osteocytes, but also cells on the bone surface, such as osteoblasts and osteoclasts. Mechanosensitive osteocytes also form hemichannels that mediate the communication between the cytoplasmic and extracellular microenvironment. This paper will discuss recent research progress regarding connexin (Cx)-forming gap junctions and hemichannels in osteocytes, osteoblasts, and other bone cells, including those richly expressing Cx43. We will then cover the recent progress regarding the regulation of these channels by mechanical loading and the role of integrins and signals in mediating Cx43 channels, and bone cell function and viability. Finally, we will summarize the recent studies regarding bone responses to mechanical unloading in Cx43 transgenic mouse models. The osteocyte has been perceived as the center of bone remodeling, and connexin channels enriched in osteocytes are a likely major player in meditating the function of bone. Based on numerous studies, connexin channels may present as a potential new therapeutic target in the treatment of bone loss and osteoporosis. This review will primarily focus on Cx43, with some discussion in other connexins expressed in bone cells.
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Affiliation(s)
- Manuel A. Riquelme
- Department of Biochemistry and Structural Biology, University of Texas Health Science Center, San Antonio, TX 78229, USA; (M.A.R.); (E.R.C.)
| | - Eduardo R. Cardenas
- Department of Biochemistry and Structural Biology, University of Texas Health Science Center, San Antonio, TX 78229, USA; (M.A.R.); (E.R.C.)
| | - Huiyun Xu
- Key Laboratory for Space Bioscience and Biotechnology, School of Life Sciences, Northwestern Polytechnical University, Xi’an 710072, China;
| | - Jean X. Jiang
- Department of Biochemistry and Structural Biology, University of Texas Health Science Center, San Antonio, TX 78229, USA; (M.A.R.); (E.R.C.)
- Correspondence: ; Tel.: +1-210-562-4094
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Jalaleddine N, El-Hajjar L, Dakik H, Shaito A, Saliba J, Safi R, Zibara K, El-Sabban M. Pannexin1 Is Associated with Enhanced Epithelial-To-Mesenchymal Transition in Human Patient Breast Cancer Tissues and in Breast Cancer Cell Lines. Cancers (Basel) 2019; 11:cancers11121967. [PMID: 31817827 PMCID: PMC6966616 DOI: 10.3390/cancers11121967] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Revised: 10/30/2019] [Accepted: 11/05/2019] [Indexed: 12/21/2022] Open
Abstract
Loss of connexin-mediated cell-cell communication is a hallmark of breast cancer progression. Pannexin1 (PANX1), a glycoprotein that shares structural and functional features with connexins and engages in cell communication with its environment, is highly expressed in breast cancer metastatic foci; however, PANX1 contribution to metastatic progression is still obscure. Here we report elevated expression of PANX1 in different breast cancer (BRCA) subtypes using RNA-seq data from The Cancer Genome Atlas (TCGA). The elevated PANX1 expression correlated with poorer outcomes in TCGA BRCA patients. In addition, gene set enrichment analysis (GSEA) revealed that epithelial-to-mesenchymal transition (EMT) pathway genes correlated positively with PANX1 expression. Pharmacological inhibition of PANX1, in MDA-MB-231 and MCF-7 breast cancer cells, or genetic ablation of PANX1, in MDA-MB-231 cells, reverted the EMT phenotype, as evidenced by decreased expression of EMT markers. In addition, PANX1 inhibition or genetic ablation decreased the invasiveness of MDA-MB-231 cells. Our results suggest PANX1 overexpression in breast cancer is associated with a shift towards an EMT phenotype, in silico and in vitro, attributing to it a tumor-promoting effect, with poorer clinical outcomes in breast cancer patients. This association offers a novel target for breast cancer therapy.
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Affiliation(s)
- Nour Jalaleddine
- Department of Biological and Environmental Sciences, Faculty of Science, Beirut Arab University, Beirut 1107-2809, Lebanon;
| | - Layal El-Hajjar
- Department of Anatomy, Cell Biology and Physiological Sciences, Faculty of Medicine, American University of Beirut, Beirut 1107-2020, Lebanon;
| | - Hassan Dakik
- University of Tours, EA 7501 GICC, CNRS ERL 7001 LNOx, CEDEX 01, 37032 Tours, France;
| | - Abdullah Shaito
- Department of Biological and Chemical Sciences, Faculty of Arts and Sciences, Lebanese International University, Beirut 1105, Lebanon;
| | - Jessica Saliba
- Department of Biology, Faculty of Sciences, Lebanese University, Hadath, Beirut 1003, Lebanon;
| | - Rémi Safi
- Department of Dermatology, Faculty of Medicine, American University of Beirut, Beirut 1107-2020, Lebanon;
| | - Kazem Zibara
- ER045-Laboratory of Stem Cells, PRASE, Department of Biology, Faculty of Sciences, Lebanese University, Hadath, Beirut 1003, Lebanon;
| | - Marwan El-Sabban
- Department of Anatomy, Cell Biology and Physiological Sciences, Faculty of Medicine, American University of Beirut, Beirut 1107-2020, Lebanon;
- Correspondence: ; Tel.: +961-1-350000 (ext. 4765-4766)
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Mohamed WKE, Mahfood M, Al Mutery A, Abdallah SH, Tlili A. A Novel Nonsense Mutation (c.414G>A; p.Trp138*) in CLDN14 Causes Hearing Loss in Yemeni Families: A Case Report. Front Genet 2019; 10:1087. [PMID: 31781163 PMCID: PMC6856671 DOI: 10.3389/fgene.2019.01087] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2019] [Accepted: 10/09/2019] [Indexed: 12/01/2022] Open
Abstract
Non-syndromic hearing loss (NSHL) is a hereditary disorder that affects many populations. Many genes are involved in NSHL and the mutational load of these genes often differs among ethnic groups. Claudin-14 (CLDN14), a tight junction protein, is known to be associated with NSHL in many populations. In this study, we aimed to identify the responsible variants in 3 different Yemeni families affected with NSHL. Firstly, clinical exome sequencing (CES) performed for 3 affected patients from these different families identified a new nonsense variant (c.414G > A) in CLDN14. This variant was then confirmed by Sanger sequencing and PCR-RFLP. Subsequently, four microsatellite markers were used to genotype these families, which revealed a founder effect for this variant. Overall, this study illustrates the implication of the CLDN14 gene in the Yemeni population with NSHL and identifies a new founder variant.
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Affiliation(s)
- Walaa Kamal Eldin Mohamed
- Department of Applied Biology, College of Sciences, University of Sharjah, Sharjah, United Arab Emirates.,Departament de Genètica i de Microbiologia, Facultat de Biociències, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Mona Mahfood
- Department of Applied Biology, College of Sciences, University of Sharjah, Sharjah, United Arab Emirates
| | - Abdullah Al Mutery
- Department of Applied Biology, College of Sciences, University of Sharjah, Sharjah, United Arab Emirates.,Human Genetics & Stem Cells Research Group, Research Institute of Sciences & Engineering, University of Sharjah, Sharjah, United Arab Emirates
| | - Sallam Hasan Abdallah
- Human Genetics & Stem Cells Research Group, Research Institute of Sciences & Engineering, University of Sharjah, Sharjah, United Arab Emirates
| | - Abdelaziz Tlili
- Department of Applied Biology, College of Sciences, University of Sharjah, Sharjah, United Arab Emirates.,Human Genetics & Stem Cells Research Group, Research Institute of Sciences & Engineering, University of Sharjah, Sharjah, United Arab Emirates
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66
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Ivanova E, Kovacs-Oller T, Sagdullaev BT. Domain-specific distribution of gap junctions defines cellular coupling to establish a vascular relay in the retina. J Comp Neurol 2019; 527:2675-2693. [PMID: 30950036 PMCID: PMC6721971 DOI: 10.1002/cne.24699] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2019] [Revised: 04/02/2019] [Accepted: 04/02/2019] [Indexed: 12/22/2022]
Abstract
In the retina, diverse functions of neuronal gap junctions (GJs) have been established. However, the distribution and function of vascular GJs are less clear. Here in the mouse retina whole mounts, we combined structural immunohistochemical analysis and a functional assessment of cellular coupling with a GJ-permeable tracer Neurobiotin to determine distribution patterns of three major vascular connexins. We found that Cx43 was expressed in punctate fashion on astroglia, surrounding all types of blood vessels and in continuous string-like structures along endothelial cell contacts in specialized regions of the vascular tree. Specifically, these Cx43-positive strings originated at the finest capillaries and extended toward the feeding artery. As this structural arrangement promoted strong and exclusive coupling of pericytes and endothelial cells along the corresponding branch, we termed this region a "vascular relay." Cx40 expression was found predominantly along the endothelial cell contacts of the primary arteries and did not overlap with Cx43-positive strings. At their occupied territories, Cx43 and Cx40 clustered with tight junctions and, to a lesser extent, with adhesion contacts, both key elements of the blood-retina barrier. Finally, Cx37 puncta were associated with the entire surface of both mural and endothelial cells across all regions of the vascular tree. This combinatorial analysis of vascular connexins and identification of the vascular relay region will serve as a structural foundation for future studies of neurovascular signaling in health and disease.
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Affiliation(s)
- Elena Ivanova
- Burke Neurological Institute, Department of Ophthalmology, Weill Cornell Medicine, White Plains, New York
| | - Tamas Kovacs-Oller
- Burke Neurological Institute, Department of Ophthalmology, Weill Cornell Medicine, White Plains, New York
| | - Botir T Sagdullaev
- Burke Neurological Institute, Department of Ophthalmology, Weill Cornell Medicine, White Plains, New York
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Li X, Guo L, Yang X, Wang J, Hou Y, Zhu S, Du J, Feng J, Xie Y, Zhuang L, He X, Liu Y. TGF-β1-induced connexin43 promotes scar formation via the Erk/MMP-1/collagen III pathway. J Oral Rehabil 2019; 47 Suppl 1:99-106. [PMID: 31175668 DOI: 10.1111/joor.12829] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2019] [Revised: 05/07/2019] [Accepted: 05/26/2019] [Indexed: 12/11/2022]
Abstract
Wound healing can be divided into different phases, and timely initiation and cessation of these stages is key to successful wound healing; otherwise, scar tissue forms in the wounded area. Connexins (Cxs) were confirmed to influence scar formation, and Cx43, an indispensable member of the Cx family, was shown to be involved in this process. Our study investigated the regulatory role of Cx43 in scar formation and the possible cell signalling pathways. We established oral mucosa and skin wound healing models in C57BL/6J mice. RT-PCR, western blotting, immunohistochemistry and immunofluorescence were used to examine the expression of ECM components and key proteins in cell signalling pathways (TGF-β1, Smad2/3, Cx43, Erk1/2 MMP-1 and collagen III). After injury, buccal mucosa wounds healed with no scar, whereas skin wounds healed with an evident scar. Nevertheless, TGF-β1 expression gradually increased by the 5th day after injury; Cx43 expression showed a similar response, with a progressive increase in the skin and a peak on day 14. In contrast, TGF-β1 and Cx43 expression in the oral mucosa remained low. The high level of TGF-β1 increased p-Smad2/3 levels and then induced Cx43, whereas increased expression of Cx43 antagonised the phosphorylation of Erk1/2, a protein downstream of Cx43, which affected MMP-1 synthesis. MMP-1 deficiency led to collagen III accumulation and facilitated scar formation. We demonstrated that TGF-β1-induced Cx43 promotes scar formation via the Erk/MMP-1/collagen III pathway.
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Affiliation(s)
- Xiaoyan Li
- Laboratory of Tissue Regeneration and Immunology and Department of Periodontics, Beijing Key Laboratory of Tooth Regeneration and Function Reconstruction, School of Stomatology, Capital Medical University, Beijing, China
| | - Lijia Guo
- Department of Orthodontics, School of Stomatology, Capital Medical University, Beijing, China
| | - Xiaohui Yang
- Laboratory of Tissue Regeneration and Immunology and Department of Periodontics, Beijing Key Laboratory of Tooth Regeneration and Function Reconstruction, School of Stomatology, Capital Medical University, Beijing, China
| | - Jingyi Wang
- School of Dental Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Yanan Hou
- Department of Orthodontics the Third Dental Center, Peking University School of Stomatology, Beijing, China
| | - Siying Zhu
- Laboratory of Tissue Regeneration and Immunology and Department of Periodontics, Beijing Key Laboratory of Tooth Regeneration and Function Reconstruction, School of Stomatology, Capital Medical University, Beijing, China
| | - Juan Du
- Laboratory of Tissue Regeneration and Immunology and Department of Periodontics, Beijing Key Laboratory of Tooth Regeneration and Function Reconstruction, School of Stomatology, Capital Medical University, Beijing, China
| | - Jie Feng
- Department of General Dentistry, School of Stomatology, Capital Medical University, Beijing, China
| | - Yongmei Xie
- Department of General Dentistry, School of Stomatology, Capital Medical University, Beijing, China
| | - Li Zhuang
- Department of Orthodontics, School of Stomatology, Capital Medical University, Beijing, China
| | - Xin He
- Department of Orthodontics, School of Stomatology, Capital Medical University, Beijing, China
| | - Yi Liu
- Laboratory of Tissue Regeneration and Immunology and Department of Periodontics, Beijing Key Laboratory of Tooth Regeneration and Function Reconstruction, School of Stomatology, Capital Medical University, Beijing, China
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68
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Singh MB, White JA, McKimm EJ, Milosevic MM, Antic SD. Mechanisms of Spontaneous Electrical Activity in the Developing Cerebral Cortex-Mouse Subplate Zone. Cereb Cortex 2019; 29:3363-3379. [PMID: 30169554 PMCID: PMC7963116 DOI: 10.1093/cercor/bhy205] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2018] [Revised: 06/28/2018] [Accepted: 08/05/2018] [Indexed: 12/15/2022] Open
Abstract
Subplate (SP) neurons exhibit spontaneous plateau depolarizations mediated by connexin hemichannels. Postnatal (P1-P6) mice show identical voltage pattern and drug-sensitivity as observed in slices from human fetal cortex; indicating that the mouse is a useful model for studying the cellular physiology of the developing neocortex. In mouse SP neurons, spontaneous plateau depolarizations were insensitive to blockers of: synaptic transmission (glutamatergic, GABAergic, or glycinergic), pannexins (probenecid), or calcium channels (mibefradil, verapamil, diltiazem); while highly sensitive to blockers of gap junctions (octanol), hemichannels (La3+, lindane, Gd3+), or glial metabolism (DLFC). Application of La3+ (100 μM) does not exert its effect on electrical activity by blocking calcium channels. Intracellular application of Gd3+ determined that Gd3+-sensitive pores (putative connexin hemichannels) reside on the membrane of SP neurons. Immunostaining of cortical sections (P1-P6) detected connexins 26, and 45 in neurons, but not connexins 32 and 36. Vimentin-positive glial cells were detected in the SP zone suggesting a potential physiological interaction between SP neurons and radial glia. SP spontaneous activity was reduced by blocking glial metabolism with DFLC or by blocking purinergic receptors by PPADS. Connexin hemichannels and ATP release from vimentin-positive glial cells may underlie spontaneous plateau depolarizations in the developing mammalian cortex.
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Affiliation(s)
- Mandakini B Singh
- Institute for Systems Genomics, Stem Cell Institute, Department of Neuroscience, UConn Health, Farmington, CT, USA
| | - Jesse A White
- Institute for Systems Genomics, Stem Cell Institute, Department of Neuroscience, UConn Health, Farmington, CT, USA
| | - Eric J McKimm
- Institute for Systems Genomics, Stem Cell Institute, Department of Neuroscience, UConn Health, Farmington, CT, USA
| | - Milena M Milosevic
- Institute for Systems Genomics, Stem Cell Institute, Department of Neuroscience, UConn Health, Farmington, CT, USA
| | - Srdjan D Antic
- Institute for Systems Genomics, Stem Cell Institute, Department of Neuroscience, UConn Health, Farmington, CT, USA
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69
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Connexin 43 hemichannels protect bone loss during estrogen deficiency. Bone Res 2019; 7:11. [PMID: 31016065 PMCID: PMC6476886 DOI: 10.1038/s41413-019-0050-2] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2018] [Revised: 02/28/2019] [Accepted: 03/18/2019] [Indexed: 02/02/2023] Open
Abstract
Estrogen deficiency in postmenopausal women is a major cause of bone loss, resulting in osteopenia, osteoporosis, and a high risk for bone fracture. Connexin 43 (Cx43) hemichannels (HCs) in osteocytes play an important role in osteocyte viability, bone formation, and remodeling. We showed here that estrogen deficiency reduced Cx43 expression and HC function. To determine if functional HCs protect osteocytes and bone loss during estrogen deficiency, we adopted an ovariectomy model in wild-type (WT) and two transgenic Cx43 mice: R76W (dominant-negative mutant inhibiting only gap junction channels) and Cx43 Δ130–136 (dominant-negative mutant compromising both gap junction channels and HCs). The bone mineral density (BMD), bone structure, and histomorphometric changes of cortical and trabecular bones after ovariectomy were investigated. Our results showed that the Δ130–136 transgenic cohort had greatly decreased vertebral trabecular bone mass compared to WT and R76W mice, associated with a significant increase in the number of apoptotic osteocyte and empty lacunae. Moreover, osteoclast surfaces in trabecular and cortical bones were increased after ovariectomy in the R76W and WT mice, respectively, but not in ∆130–136 mice. These data demonstrate that impairment of Cx43 HCs in osteocytes accelerates vertebral trabecular bone loss and increase in osteocyte apoptosis, and further suggest that Cx43 HCs in osteocytes protect trabecular bone against catabolic effects due to estrogen deficiency. Channels that form between cells and their extracellular environment help protect bone tissue from the damage wrought by low estrogen levels, a major cause of bone loss in post-menopausal women. Jean Jiang from the UT Health San Antonio and colleagues showed that depleting the estrogen hormone in mouse bone cells reduced levels of connexin 43 and impaired the protein’s ability to forms pores known as ‘hemichannels’. The researchers surgically removed the ovaries of various mouse strains to induce estrogen deficiencies. They found that transgenic mice without working hemichannels had reduced bone mass compared to normal mice or mice that could make hemichannels but lacked the ability for those channels to come together to form complete passageways. The findings highlight the importance of connexin 43 hemichannels in protecting bone tissue against osteoporosis.
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70
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Dispelling myths about connexins, pannexins and P2X7 in hypoxic-ischemic central nervous system. Neurosci Lett 2019; 695:76-85. [PMID: 29195910 DOI: 10.1016/j.neulet.2017.11.044] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2017] [Revised: 10/07/2017] [Accepted: 11/21/2017] [Indexed: 01/17/2023]
Abstract
In membrane physiology, as in other fields, myths or speculations may be repeated so often and so widely that they are perceived as facts. To some extent, this has occurred with regard to gap junctions, hemichannels, pannexin channels and P2X7 (ionotropic receptors), especially concerning the interpretation of the individual role of these channels in hypoxic-ischemic CNS since these channels may be closed by the same pharmacological blockers. Significance of existing controversial data are highlighted and contradictory views from different groups are critically discussed herein.
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71
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Novielli-Kuntz NM, Jelen M, Barr K, DeLalio LJ, Feng Q, Isakson BE, Gros R, Laird DW. Ablation of both Cx40 and Panx1 results in similar cardiovascular phenotypes exhibited in Cx40 knockout mice. Biosci Rep 2019; 39:BSR20182350. [PMID: 30745457 PMCID: PMC6393227 DOI: 10.1042/bsr20182350] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2018] [Revised: 01/10/2019] [Accepted: 02/05/2019] [Indexed: 11/30/2022] Open
Abstract
Connexins (Cxs) and pannexins (Panxs) are highly regulated large-pore channel-forming proteins that participate in cellular communication via small molecular exchange with the extracellular microenvironment, or in the case of connexins, directly between cells. Given the putative functional overlap between single membrane-spanning connexin hemichannels and Panx channels, and cardiovascular system prevalence, we generated the first Cx40-/-Panx1-/- mouse with the anticipation that this genetic modification would lead to a severe cardiovascular phenotype. Mice null for both Cx40 and Panx1 produced litter sizes and adult growth progression similar to wild-type (WT), Cx40-/- and Panx1-/- mice. Akin to Cx40-/- mice, Cx40-/-Panx1-/- mice exhibited cardiac hypertrophy and elevated systolic, diastolic, and mean arterial blood pressure compared with WT and Panx1-/- mice; however assessment of left ventricular ejection fraction and fractional shortening revealed no evidence of cardiac dysfunction between groups. Furthermore, Cx40-/-, Panx1-/-, and Cx40-/-Panx1-/- mice demonstrated impaired endothelial-mediated vasodilation of aortic segments to increasing concentrations of methacholine (MCh) compared with WT, highlighting roles for both Cx40 and Panx1 in vascular endothelial cell (EC) function. Surprisingly, elevated kidney renin mRNA expression, plasma renin activity, and extraglomerular renin-producing cell populations found in Cx40-/- mice was further exaggerated in double knockout mice. Thus, while gestation and gross development were conserved in Cx40-/-Panx1-/- mice, they exhibit cardiac hypertrophy, hypertension, and impaired endothelial-mediated vasodilation that phenocopies Cx40-/- mice. Nevertheless, the augmented renin homeostasis observed in the double knockout mice suggests that both Cx40 and Panx1 may play an integrative role.
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Affiliation(s)
| | - Meghan Jelen
- Department of Anatomy and Cell Biology, University of Western Ontario, London, Canada
| | - Kevin Barr
- Department of Anatomy and Cell Biology, University of Western Ontario, London, Canada
| | - Leon J DeLalio
- Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, VA, U.S.A
| | - Qingping Feng
- Department of Physiology and Pharmacology London, ON, Canada
| | - Brant E Isakson
- Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, VA, U.S.A
| | - Robert Gros
- Department of Physiology and Pharmacology London, ON, Canada
- Robarts Research Institute, Schulich School of Medicine & Dentistry, University of Western Ontario, London, ON, Canada
| | - Dale W Laird
- Department of Anatomy and Cell Biology, University of Western Ontario, London, Canada
- Department of Physiology and Pharmacology London, ON, Canada
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72
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Xing L, Yang T, Cui S, Chen G. Connexin Hemichannels in Astrocytes: Role in CNS Disorders. Front Mol Neurosci 2019; 12:23. [PMID: 30787868 PMCID: PMC6372977 DOI: 10.3389/fnmol.2019.00023] [Citation(s) in RCA: 122] [Impact Index Per Article: 24.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2018] [Accepted: 01/21/2019] [Indexed: 12/19/2022] Open
Abstract
In the central nervous system (CNS), astrocytes form networks interconnected by gap junctions made from connexins of the subtypes Cx30 and Cx43. When unopposed by an adjoining hemichannel, astrocytic connexins can act as hemichannels to control the release of small molecules such as ATP and glutamate into the extracellular space. Accruing evidence indicates that astrocytic connexins are crucial for the coordination and maintenance of physiologic CNS activity. Here we provide an update on the role of astrocytic connexins in neurodegenerative disorders, glioma, and ischemia. In addition, we address the regulation of Cx43 in chronic pain.
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Affiliation(s)
- LingYan Xing
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-innovation Center of Neuroregeneration, Nantong University, Nantong, China
| | - Tuo Yang
- Department of Hand Surgery, China-Japan Union Hospital of Jilin University, Changchun, China
| | - ShuSen Cui
- Department of Hand Surgery, China-Japan Union Hospital of Jilin University, Changchun, China
| | - Gang Chen
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-innovation Center of Neuroregeneration, Nantong University, Nantong, China.,Department of Anesthesiology, Affiliated Hospital of Nantong University, Nantong, China
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73
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Plotkin LI, Bruzzaniti A. Molecular signaling in bone cells: Regulation of cell differentiation and survival. ADVANCES IN PROTEIN CHEMISTRY AND STRUCTURAL BIOLOGY 2019; 116:237-281. [PMID: 31036293 PMCID: PMC7416488 DOI: 10.1016/bs.apcsb.2019.01.002] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The achievement of proper bone mass and architecture, and their maintenance throughout life requires the concerted actions of osteoblasts, the bone forming cells, and osteoclasts, the bone resorbing cells. The differentiation and activity of osteoblasts and osteoclasts are regulated by molecules produced by matrix-embedded osteocytes, as well as by cross talk between osteoblasts and osteoclasts through secreted factors. In addition, it is likely that direct contact between osteoblast and osteoclast precursors, and the contact of these cells with osteocytes and cells in the bone marrow, also modulates bone cell differentiation and function. With the advancement of molecular and genetic tools, our comprehension of the intracellular signals activated in bone cells has evolved significantly, from early suggestions that osteoblasts and osteoclasts have common precursors and that osteocytes are inert cells in the bone matrix, to the very sophisticated understanding of a network of receptors, ligands, intracellular kinases/phosphatases, transcription factors, and cell-specific genes that are known today. These advances have allowed the design and FDA-approval of new therapies to preserve and increase bone mass and strength in a wide variety of pathological conditions, improving bone health from early childhood to the elderly. We have summarized here the current knowledge on selected intracellular signal pathways activated in osteoblasts, osteocytes, and osteoclasts.
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Affiliation(s)
- Lilian I Plotkin
- Department of Anatomy and Cell Biology, Indiana University School of Medicine, Indianapolis, IN, United States; Indiana Center for Musculoskeletal Health, Indianapolis, IN, United States; Roudebush Veterans Administration Medical Center, Indianapolis, IN, United States.
| | - Angela Bruzzaniti
- Department of Anatomy and Cell Biology, Indiana University School of Medicine, Indianapolis, IN, United States; Indiana Center for Musculoskeletal Health, Indianapolis, IN, United States; Department of Biomedical and Applied Sciences, Indiana University School of Dentistry, Indianapolis, IN, United States
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74
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Evidence for an autosomal recessive pattern of inheritance in Keratitis-ichthyosis-deafness (KID) syndrome: Exome sequencing reveals a novel homozygous GJB2 mutation. Meta Gene 2019. [DOI: 10.1016/j.mgene.2018.10.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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75
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Sinyuk M, Mulkearns-Hubert EE, Reizes O, Lathia J. Cancer Connectors: Connexins, Gap Junctions, and Communication. Front Oncol 2018; 8:646. [PMID: 30622930 PMCID: PMC6308394 DOI: 10.3389/fonc.2018.00646] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2018] [Accepted: 12/10/2018] [Indexed: 12/21/2022] Open
Abstract
Despite concerted clinical and research efforts, cancer is a leading cause of death worldwide. Surgery, radiation, and chemotherapy have remained the most common standard-of-care strategies against cancer for decades. However, the side effects of these therapies demonstrate the need to investigate adjuvant novel treatment modalities that minimize the harm caused to healthy cells and tissues. Normal and cancerous cells require communication amongst themselves and with their surroundings to proliferate and drive tumor growth. It is vital to understand how intercellular and external communication impacts tumor cell malignancy. To survive and grow, tumor cells, and their normal counterparts utilize cell junction molecules including gap junctions (GJs), tight junctions, and adherens junctions to provide contact points between neighboring cells and the extracellular matrix. GJs are specialized structures composed of a family of connexin proteins that allow the free diffusion of small molecules and ions directly from the cytoplasm of adjacent cells, without encountering the extracellular milieu, which enables rapid, and coordinated cellular responses to internal and external stimuli. Importantly, connexins perform three main cellular functions. They enable direct gap junction intercellular communication (GJIC) between cells, form hemichannels to allow cell communication with the extracellular environment, and serve as a site for protein-protein interactions to regulate signaling pathways. Connexins themselves have been found to promote tumor cell growth and invasiveness, contributing to the overall tumorigenicity and have emerged as attractive anti-tumor targets due to their functional diversity. However, connexins can also serve as tumor suppressors, and therefore, a complete understanding of the roles of the connexins and GJs in physiological and pathophysiological conditions is needed before connexin targeting strategies are applied. Here, we discuss how the three aspects of connexin function, namely GJIC, hemichannel formation, and connexin-protein interactions, function in normal cells, and contribute to tumor cell growth, proliferation, and death. Finally, we discuss the current state of anti-connexin therapies and speculate which role may be most amenable for the development of targeting strategies.
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Affiliation(s)
- Maksim Sinyuk
- Department of Biological, Geological, and Environmental Sciences, Cleveland State University, Cleveland, OH, United States
- Department of Cellular and Molecular Medicine, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, United States
| | - Erin E. Mulkearns-Hubert
- Department of Cellular and Molecular Medicine, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, United States
| | - Ofer Reizes
- Department of Biological, Geological, and Environmental Sciences, Cleveland State University, Cleveland, OH, United States
- Department of Cellular and Molecular Medicine, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, United States
- Cleveland Clinic Lerner College of Medicine, Cleveland Clinic, Cleveland, OH, United States
- Case Comprehensive Cancer Center, Case Western University, Cleveland, OH, United States
| | - Justin Lathia
- Department of Biological, Geological, and Environmental Sciences, Cleveland State University, Cleveland, OH, United States
- Department of Cellular and Molecular Medicine, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, United States
- Cleveland Clinic Lerner College of Medicine, Cleveland Clinic, Cleveland, OH, United States
- Case Comprehensive Cancer Center, Case Western University, Cleveland, OH, United States
- Rose Ella Burkhardt Brain Tumor and Neuro-Oncology Center, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, United States
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76
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Kajiwara Y, Wang E, Wang M, Sin WC, Brennand KJ, Schadt E, Naus CC, Buxbaum J, Zhang B. GJA1 (connexin43) is a key regulator of Alzheimer's disease pathogenesis. Acta Neuropathol Commun 2018; 6:144. [PMID: 30577786 PMCID: PMC6303945 DOI: 10.1186/s40478-018-0642-x] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Accepted: 12/01/2018] [Indexed: 12/02/2022] Open
Abstract
GJA1 (connexin43) has been predicted as the top key driver of an astrocyte enriched subnetwork associated with Alzheimer's disease (AD). In this study, we comprehensively examined GJA1 expression across 29 transcriptomic and proteomic datasets from post-mortem AD and normal control brains. We demonstrated that GJA1 was strongly associated with AD amyloid and tau pathologies and cognitive functions. RNA sequencing analysis of Gja1-/- astrocytes validated that Gja1 regulated the subnetwork identified in AD, and many genes involved in Aβ metabolism. Astrocytes lacking Gja1 showed reduced Apoe protein levels as well as impaired Aβ phagocytosis. Consistent with this, wildtype neurons co-cultured with Gja1-/- astrocytes contained higher levels of Aβ species than those with wildtype astrocytes. Moreover, Gja1-/- astrocytes was more neuroprotective under Aβ stress. Our results underscore the importance of GJA1 in AD pathogenesis and its potential for further investigation as a promising pharmacological target in AD.
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Affiliation(s)
- Yuji Kajiwara
- Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
- Current address: Denali Therapeutics,, South San Francisco,, CA, 94080, USA
| | - Erming Wang
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
- Mount Sinai Center for Transformative Disease Modeling, Icahn Institute of Genomics and Multiscale Biology, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
| | - Minghui Wang
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
- Mount Sinai Center for Transformative Disease Modeling, Icahn Institute of Genomics and Multiscale Biology, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
| | - Wun Chey Sin
- Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, British Columbia, V6T 1Z3, Canada
| | - Kristen J Brennand
- Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
- Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
- Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
| | - Eric Schadt
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
- Mount Sinai Center for Transformative Disease Modeling, Icahn Institute of Genomics and Multiscale Biology, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
| | - Christian C Naus
- Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, British Columbia, V6T 1Z3, Canada
| | - Joseph Buxbaum
- Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
- Mount Sinai Center for Transformative Disease Modeling, Icahn Institute of Genomics and Multiscale Biology, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
- Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
- Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
| | - Bin Zhang
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA.
- Mount Sinai Center for Transformative Disease Modeling, Icahn Institute of Genomics and Multiscale Biology, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA.
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Arnhold S, Elashry MI, Klymiuk MC, Wenisch S. Biological macromolecules and mesenchymal stem cells: Basic research for regenerative therapies in veterinary medicine. Int J Biol Macromol 2018; 123:889-899. [PMID: 30452985 DOI: 10.1016/j.ijbiomac.2018.11.158] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2018] [Revised: 11/05/2018] [Accepted: 11/15/2018] [Indexed: 02/07/2023]
Affiliation(s)
- Stefan Arnhold
- Institute of Veterinary Anatomy-, Histology and -Embryology, University of Giessen, 35392 Giessen, Germany
| | - Mohamed I Elashry
- Institute of Veterinary Anatomy-, Histology and -Embryology, University of Giessen, 35392 Giessen, Germany; Anatomy and Embryology Department, Faculty of Veterinary Medicine, University of Mansoura 35516, Egypt.
| | - Michele C Klymiuk
- Institute of Veterinary Anatomy-, Histology and -Embryology, University of Giessen, 35392 Giessen, Germany
| | - Sabine Wenisch
- Clinic of Small Animals, c/o Institute of Veterinary Anatomy, Histology and Embryology, Justus Liebig University of Giessen 35392, Giessen, Germany
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78
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Li Q, Li QQ, Jia JN, Liu ZQ, Zhou HH, Mao XY. Targeting gap junction in epilepsy: Perspectives and challenges. Biomed Pharmacother 2018; 109:57-65. [PMID: 30396092 DOI: 10.1016/j.biopha.2018.10.068] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2018] [Revised: 10/08/2018] [Accepted: 10/12/2018] [Indexed: 12/21/2022] Open
Abstract
Gap junctions (GJs) are multiple cellular intercellular connections that allow ions to pass directly into the cytoplasm of neighboring cells. Electrical coupling mediated by GJs plays a role in the generation of highly synchronous electrical activity. Accumulative investigations show that GJs in the brain are involved in the generation, synchronization and maintenance of seizure events. At the same time, GJ blockers exert potent curative potential on epilepsy in vivo or in vitro. This review aims to shed light on the role of GJs in epileptogenesis. Targeting GJs is likely to be served as a novel therapeutic approach on epileptic patients.
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Affiliation(s)
- Qin Li
- Department of Clinical Pharmacology, Xiangya Hospital, Central South University, Changsha 410008, China; Institute of Clinical Pharmacology, Hunan Key Laboratory of Pharmacogenetics, Central South University, Changsha 410078, Hunan, China
| | - Qiu-Qi Li
- Department of Clinical Pharmacology, Xiangya Hospital, Central South University, Changsha 410008, China; Institute of Clinical Pharmacology, Hunan Key Laboratory of Pharmacogenetics, Central South University, Changsha 410078, Hunan, China
| | - Ji-Ning Jia
- Department of Clinical Pharmacology, Xiangya Hospital, Central South University, Changsha 410008, China; Institute of Clinical Pharmacology, Hunan Key Laboratory of Pharmacogenetics, Central South University, Changsha 410078, Hunan, China
| | - Zhao-Qian Liu
- Department of Clinical Pharmacology, Xiangya Hospital, Central South University, Changsha 410008, China; Institute of Clinical Pharmacology, Hunan Key Laboratory of Pharmacogenetics, Central South University, Changsha 410078, Hunan, China
| | - Hong-Hao Zhou
- Department of Clinical Pharmacology, Xiangya Hospital, Central South University, Changsha 410008, China; Institute of Clinical Pharmacology, Hunan Key Laboratory of Pharmacogenetics, Central South University, Changsha 410078, Hunan, China
| | - Xiao-Yuan Mao
- Department of Clinical Pharmacology, Xiangya Hospital, Central South University, Changsha 410008, China; Institute of Clinical Pharmacology, Hunan Key Laboratory of Pharmacogenetics, Central South University, Changsha 410078, Hunan, China.
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79
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Fan Q, Mao H, Xie L, Pi X. Prolyl Hydroxylase Domain-2 Protein Regulates Lipopolysaccharide-Induced Vascular Inflammation. THE AMERICAN JOURNAL OF PATHOLOGY 2018; 189:200-213. [PMID: 30339838 DOI: 10.1016/j.ajpath.2018.09.012] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/09/2018] [Revised: 09/12/2018] [Accepted: 09/13/2018] [Indexed: 12/25/2022]
Abstract
Acute lung injury and its more severe form, acute respiratory distress syndrome, are life-threatening respiratory disorders. Overwhelming pulmonary inflammation and endothelium disruption are commonly observed. Endothelial cells (ECs) are well recognized as key regulators in leukocyte adhesion and migration in response to bacterial infection. Prolyl hydroxylase domain (PHD)-2 protein, a major PHD in ECs, plays a critical role in intracellular oxygen homeostasis, angiogenesis, and pulmonary hypertension. However, its role in endothelial inflammatory response is unclear. We investigated the role of PHD2 in ECs during endotoxin-induced lung inflammatory responses with EC-specific PHD2 inducible knockout mice. On lipopolysaccharide challenge, PHD2 depletion in ECs attenuates lipopolysaccharide-induced increases of lung vascular permeability, edema, and inflammatory cell infiltration. Moreover, EC-specific PHD2 inducible knockout mice exhibit improved adherens junction integrity and endothelial barrier function. Mechanistically, PHD2 knockdown induces vascular endothelial cadherin in mouse lung microvascular primary endothelial cells. Moreover, PHD2 knockdown can increase hypoxia-inducible factor/vascular endothelial protein tyrosine phosphatase signaling and reactive oxygen species-dependent p38 activation, leading to the induction of vascular endothelial cadherin. Data indicate that PHD2 depletion prevents the formation of leaky vessels and edema by regulating endothelial barrier function. It provides direct in vivo evidence to suggest that PHD2 plays a pivotal role in vascular inflammation. The inhibition of endothelial PHD2 activity may be a new therapeutic strategy for acute inflammatory diseases.
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Affiliation(s)
- Qiying Fan
- Cardiovascular Research Institute, Section of Athero and Lipo, Department of Medicine, Baylor College of Medicine, Houston, Texas
| | - Hua Mao
- Cardiovascular Research Institute, Section of Athero and Lipo, Department of Medicine, Baylor College of Medicine, Houston, Texas
| | - Liang Xie
- Cardiovascular Research Institute, Section of Athero and Lipo, Department of Medicine, Baylor College of Medicine, Houston, Texas.
| | - Xinchun Pi
- Cardiovascular Research Institute, Section of Athero and Lipo, Department of Medicine, Baylor College of Medicine, Houston, Texas.
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80
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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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81
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Lemcke H, David R. Potential mechanisms of microRNA mobility. Traffic 2018; 19:910-917. [PMID: 30058163 DOI: 10.1111/tra.12606] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2018] [Revised: 07/26/2018] [Accepted: 07/26/2018] [Indexed: 12/29/2022]
Abstract
microRNAs (miRNAs) are important epigenetic modulators of gene expression that control cellular physiology as well as tissue homeostasis, and development. In addition to the temporal aspects of miRNA-mediated gene regulation, the intracellular localization of miRNA is crucial for its silencing activity. Recent studies indicated that miRNA is even translocated between cells via gap junctional cell-cell contacts, allowing spatiotemporal modulation of gene expression within multicellular systems. Although non coding RNA remains a focus of intense research, studies regarding the intra-and intercellular mobility of small RNAs are still largely missing. Emerging data from experimental and computational work suggest the involvement of transport mechanisms governing proper localization of miRNA in single cells and cellular syncytia. Based on these data, we discuss a model of miRNA translocation that could help to address the spatial aspects of miRNA function and the impact of miRNA molecules on the intercellular signaling network.
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Affiliation(s)
- Heiko Lemcke
- Department of Cardiac Surgery, Reference and Translation Center for Cardiac Stem Cell Therapy (RTC), University of Rostock, Rostock, Germany.,Department Life, Light & Matter, University of Rostock, 18051 Rostock, Germany
| | - Robert David
- Department of Cardiac Surgery, Reference and Translation Center for Cardiac Stem Cell Therapy (RTC), University of Rostock, Rostock, Germany.,Department Life, Light & Matter, University of Rostock, 18051 Rostock, Germany
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82
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Simmons S, Erfinanda L, Bartz C, Kuebler WM. Novel mechanisms regulating endothelial barrier function in the pulmonary microcirculation. J Physiol 2018; 597:997-1021. [PMID: 30015354 DOI: 10.1113/jp276245] [Citation(s) in RCA: 52] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2018] [Accepted: 05/25/2018] [Indexed: 12/11/2022] Open
Abstract
The pulmonary epithelial and vascular endothelial cell layers provide two sequential physical and immunological barriers that together form a semi-permeable interface and prevent alveolar and interstitial oedema formation. In this review, we focus specifically on the continuous endothelium of the pulmonary microvascular bed that warrants strict control of the exchange of gases, fluid, solutes and circulating cells between the plasma and the interstitial space. The present review provides an overview of emerging molecular mechanisms that permit constant transcellular exchange between the vascular and interstitial compartment, and cause, prevent or reverse lung endothelial barrier failure under experimental conditions, yet with a clinical perspective. Based on recent findings and at times seemingly conflicting results we discuss emerging paradigms of permeability regulation by altered ion transport as well as shifts in the homeostasis of sphingolipids, angiopoietins and prostaglandins.
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Affiliation(s)
- Szandor Simmons
- Institute of Physiology, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Lasti Erfinanda
- Institute of Physiology, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Christoph Bartz
- Institute of Physiology, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Wolfgang M Kuebler
- Institute of Physiology, Charité-Universitätsmedizin Berlin, Berlin, Germany.,Keenan Research Centre for Biomedical Science, St. Michael's Hospital, Toronto, ON, Canada.,Departments of Surgery and Physiology, University of Toronto, Toronto, ON, Canada
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83
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Iikawa N, Yamamoto Y, Kawasaki Y, Nishijima-Matsunobu A, Suzuki M, Yamada T, Omori Y. Intrinsic Oncogenic Function of Intracellular Connexin26 Protein in Head and Neck Squamous Cell Carcinoma Cells. Int J Mol Sci 2018; 19:ijms19072134. [PMID: 30041406 PMCID: PMC6073371 DOI: 10.3390/ijms19072134] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2018] [Revised: 07/19/2018] [Accepted: 07/21/2018] [Indexed: 02/07/2023] Open
Abstract
It has long been known that the gap junction is down-regulated in many tumours. One of the downregulation mechanisms is the translocation of connexin, a gap junction protein, from cell membrane into cytoplasm, nucleus, or Golgi apparatus. Interestingly, as tumours progress and reinforce their malignant phenotype, the amount of aberrantly-localised connexin increases in different malignant tumours including oesophageal squamous cell carcinoma, thus suggesting that such an aberrantly-localised connexin should be oncogenic, although gap junctional connexins are often tumour-suppressive. To define the dual roles of connexin in head and neck squamous cell carcinoma (HNSCC), we introduced the wild-type connexin26 (wtCx26) or the mutant Cx26 (icCx26) gene, the product of which carries the amino acid sequence AKKFF, an endoplasmic reticulum-Golgi retention signal, at the C-terminus and is not sorted to cell membrane, into the human FaDu hypopharyngeal cancer cell line that had severely impaired the expression of connexin during carcinogenesis. wtCx26 protein was trafficked to the cell membrane and formed gap junction, which successfully exerted cell-cell communication. On the other hand, the icCx26 protein was co-localised with a Golgi marker, as revealed by immunofluorescence, and thus was retained on the way to the cell membrane. While the forced expression of wtCx26 suppressed both cell proliferation in vitro and tumorigenicity in mice in vivo, icCx26 significantly enhanced both cell proliferation and tumorigenicity compared with the mock control clones, indicating that an excessive accumulation of connexin protein in intracellular domains should be involved in cancer progression and that restoration of proper subcellular sorting of connexin might be a therapeutic strategy to control HNSCC.
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Affiliation(s)
- Nobuko Iikawa
- Department of Molecular and Tumour Pathology, Akita University Graduate School of Medicine, Akita 010-8543, Japan.
- Department of Otorhinolaryngology and Head-and-Neck Surgery, Akita University Graduate School of Medicine, Akita 010-8543, Japan.
| | - Yohei Yamamoto
- Department of Molecular and Tumour Pathology, Akita University Graduate School of Medicine, Akita 010-8543, Japan.
| | - Yohei Kawasaki
- Department of Otorhinolaryngology and Head-and-Neck Surgery, Akita University Graduate School of Medicine, Akita 010-8543, Japan.
| | - Aki Nishijima-Matsunobu
- Department of Molecular and Tumour Pathology, Akita University Graduate School of Medicine, Akita 010-8543, Japan.
| | - Maya Suzuki
- Department of Molecular and Tumour Pathology, Akita University Graduate School of Medicine, Akita 010-8543, Japan.
| | - Takechiyo Yamada
- Department of Otorhinolaryngology and Head-and-Neck Surgery, Akita University Graduate School of Medicine, Akita 010-8543, Japan.
| | - Yasufumi Omori
- Department of Molecular and Tumour Pathology, Akita University Graduate School of Medicine, Akita 010-8543, Japan.
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84
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Huang D, Chen YS, Green CR, Rupenthal ID. Hyaluronic acid coated albumin nanoparticles for targeted peptide delivery in the treatment of retinal ischaemia. Biomaterials 2018; 168:10-23. [DOI: 10.1016/j.biomaterials.2018.03.034] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2018] [Revised: 03/15/2018] [Accepted: 03/18/2018] [Indexed: 12/19/2022]
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85
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Grek CL, Sheng Z, Naus CC, Sin WC, Gourdie RG, Ghatnekar GG. Novel approach to temozolomide resistance in malignant glioma: connexin43-directed therapeutics. Curr Opin Pharmacol 2018; 41:79-88. [PMID: 29803991 DOI: 10.1016/j.coph.2018.05.002] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2018] [Revised: 04/30/2018] [Accepted: 05/03/2018] [Indexed: 01/03/2023]
Abstract
Resistance of malignant glioma, including glioblastoma (GBM), to the chemotherapeutic temozolomide (TMZ) remains a key obstacle in treatment strategies. The gap junction protein connexin43 (Cx43) has complex roles in the establishment, progression, and persistence of malignant glioma. Recent findings demonstrate that connexins play an important role in the microenvironment of malignant glioma and that Cx43 is capable of conferring chemotherapeutic resistance to GBM cells. Carboxyl-terminal Cx43 peptidomimetics show therapeutic promise in overcoming TMZ resistance via mechanisms that may include modulating junctional activity between tumor cells and peritumoral cells and/or downstream molecular signaling events mediated by Cx43 protein binding. High levels of intra-tumor and inter-tumor heterogeneity make it difficult to clearly define specific populations for Cx43-targeted therapy; hence, development of in vitro models that better mimic the microenvironment of malignant glioma, and the incorporation of patient-derived stem cells, could provide opportunities for patient-specific drug screening. This review summarizes recent advances in understanding the roles of Cx43 in malignant glioma, with a special focus on tumor microenvironment, TMZ resistance, and therapeutic opportunity offered by Cx43 peptidomimetics.
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Affiliation(s)
| | - Zhi Sheng
- Virginia Tech Carilion Research Institute, Roanoke, VA, USA; Faculty of Health Science, Virginia Tech, Blacksburg, VA, USA; Department of Biological Sciences and Pathobiology, Virginia-Maryland College of Veterinary Medicine, Virginia Tech, Blacksburg, VA, USA; Department of Internal Medicine, Virginia Tech Carilion School of Medicine, Roanoke, VA, USA
| | - Christian C Naus
- Department of Cellular and Physiological Science, Life Sciences Institute, University of British Columbia, Vancouver, Canada
| | - Wun Chey Sin
- Department of Cellular and Physiological Science, Life Sciences Institute, University of British Columbia, Vancouver, Canada
| | - Robert G Gourdie
- Virginia Tech Carilion Research Institute, Roanoke, VA, USA; Faculty of Health Science, Virginia Tech, Blacksburg, VA, USA; Virginia Tech-Wake Forest University School of Biomedical Engineering and Sciences, Blacksburg, VA, USA; Department of Emergency Medicine, Virginia Tech Carilion School of Medicine, Roanoke, VA, USA
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86
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Conflicting Roles of Connexin43 in Tumor Invasion and Growth in the Central Nervous System. Int J Mol Sci 2018; 19:ijms19041159. [PMID: 29641478 PMCID: PMC5979343 DOI: 10.3390/ijms19041159] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2018] [Revised: 04/05/2018] [Accepted: 04/09/2018] [Indexed: 12/24/2022] Open
Abstract
The tumor microenvironment is known to have increased levels of cytokines and metabolites, such as glutamate, due to their release from the surrounding cells. A normal cell around the tumor that responds to the inflammatory environment is likely to be subsequently altered. We discuss how these abnormalities will support tumor survival via the actions of gap junctions (GJs) and hemichannels (HCs) which are composed of hexamer of connexin43 (Cx43) protein. In particular, we discuss how GJ intercellular communication (GJIC) in glioma cells, the primary brain tumor, is a regulatory factor and its attenuation leads to tumor invasion. In contrast, the astrocytes, which are normal cells around the glioma, are “hijacked” by tumor cells, either by receiving the transmission of malignant substances from the cancer cells via GJIC, or perhaps via astrocytic HC activity through the paracrine signaling which enable the delivery of these substances to the distal astrocytes. This astrocytic signaling would promote tumor expansion in the brain. In addition, brain metastasis from peripheral tissues has also been known to be facilitated by GJs formed between cerebral vascular endothelial cells and cancer cells. Astrocytes and microglia are generally thought to eliminate cancer cells at the blood–brain barrier. In contrast, some reports suggest they facilitate tumor progression as tumor cells take advantage of the normal functions of astrocytes that support the survival of the neurons by exchanging nutrients and metabolites. In summary, GJIC is essential for the normal physiological function of growth and allowing the diffusion of physiological substances. Therefore, whether GJIC is cancer promoting or suppressing may be dependent on what permeates through GJs, when it is active, and to which cells. The nature of GJs, which has been ambiguous in brain tumor progression, needs to be revisited and understood together with new findings on Cx proteins and HC activities.
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87
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Abstract
Adenosine triphosphate (ATP) has been well established as an important extracellular ligand of autocrine signaling, intercellular communication, and neurotransmission with numerous physiological and pathophysiological roles. In addition to the classical exocytosis, non-vesicular mechanisms of cellular ATP release have been demonstrated in many cell types. Although large and negatively charged ATP molecules cannot diffuse across the lipid bilayer of the plasma membrane, conductive ATP release from the cytosol into the extracellular space is possible through ATP-permeable channels. Such channels must possess two minimum qualifications for ATP permeation: anion permeability and a large ion-conducting pore. Currently, five groups of channels are acknowledged as ATP-release channels: connexin hemichannels, pannexin 1, calcium homeostasis modulator 1 (CALHM1), volume-regulated anion channels (VRACs, also known as volume-sensitive outwardly rectifying (VSOR) anion channels), and maxi-anion channels (MACs). Recently, major breakthroughs have been made in the field by molecular identification of CALHM1 as the action potential-dependent ATP-release channel in taste bud cells, LRRC8s as components of VRACs, and SLCO2A1 as a core subunit of MACs. Here, the function and physiological roles of these five groups of ATP-release channels are summarized, along with a discussion on the future implications of understanding these channels.
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88
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Abstract
Purpose of Review Considerable progress has been made in the field of stem cell research; nonetheless, the use of stem cells for regenerative medicine therapies, for either endogenous tissue repair or cellular grafts post injury, remains a challenge. To better understand how to maintain stem cell potential in vivo and promote differentiation ex vivo, it is fundamentally important to elucidate the interactions between stem cells and their surrounding partners within their distinct niches. Recent Findings Among the vast array of proteins depicted as mediators for cell-to-cell interactions, connexin-comprised gap junctions play pivotal roles in the regulation of stem cell fate both in vivo and in vitro. Summary This review summarizes and illustrates the current knowledge regarding the multifaceted roles of Cx43, specifically, in various stem cell niches.
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Affiliation(s)
- Nafiisha Genet
- Department of Medicine, Genetics and Biomedical Engineering, Yale Cardiovascular Research Center, Vascular Biology Therapeutics Program, New Haven, USA.,2Yale Stem Cell Center Yale University School of Medicine, 300 George St, New Haven, CT 06511 USA
| | - Neha Bhatt
- Department of Medicine, Genetics and Biomedical Engineering, Yale Cardiovascular Research Center, Vascular Biology Therapeutics Program, New Haven, USA.,2Yale Stem Cell Center Yale University School of Medicine, 300 George St, New Haven, CT 06511 USA
| | - Antonin Bourdieu
- Department of Medicine, Genetics and Biomedical Engineering, Yale Cardiovascular Research Center, Vascular Biology Therapeutics Program, New Haven, USA.,2Yale Stem Cell Center Yale University School of Medicine, 300 George St, New Haven, CT 06511 USA
| | - Karen K Hirschi
- Department of Medicine, Genetics and Biomedical Engineering, Yale Cardiovascular Research Center, Vascular Biology Therapeutics Program, New Haven, USA.,2Yale Stem Cell Center Yale University School of Medicine, 300 George St, New Haven, CT 06511 USA
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89
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Palacio-Mancheno PE, Evashwick-Rogler TW, Laudier DM, Purmessur D, Iatridis JC. Hyperosmolarity induces notochordal cell differentiation with aquaporin3 upregulation and reduced N-cadherin expression. J Orthop Res 2018; 36:788-798. [PMID: 28853179 PMCID: PMC5832547 DOI: 10.1002/jor.23715] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/21/2017] [Accepted: 08/19/2017] [Indexed: 02/04/2023]
Abstract
The nucleus pulposus (NP) of intervertebral discs (IVD) undergoes dramatic changes with aging including loss of its gelatinous structure and large, vacuolated notochordal cells (NCs) in favor of a matrix-rich structure populated by small NP cells (sNPCs). NP maturation also involves a loading-pattern shift from pressurization to matrix deformations, and these events are thought to predispose to degeneration. Little is known of the triggering events and cellular alterations involved with NP maturation, which remains a fundamental open spinal mechanobiology question. A mouse IVD organ culture model was used to test the hypotheses that hyperosmotic overloading will induce NP maturation with transition of NCs to sNPCs while also increasing matrix accumulation and altering osmoregulatory and mechanotransductive proteins. Results indicated that static hyperosmolarity, as might occur during growth, caused maturation of NCs to sNPCs and involved a cellular differentiation process since known NC markers (cytokeratin-8, -19, and sonic hedgehog) persisted without increased cell apoptosis. Osmosensitive channels Aquaporin 3 (Aqp3) and transient receptor potential vanilloid-4 (TRPV4) expression were both modified with altered osmolarity, but increased Aqp3 with hyperosmolarity was associated with NC to sNPC differentiation. NC to sNPC differentiation was accompanied by a shift in cellular mechanotransduction proteins with decreased N-cadherin adhesions and increased Connexin 43 connexons. We conclude that hyperosmotic overloading can promote NC differentiation into sNPCs. This study identified osmolarity as a triggering mechanism for notochordal cell differentiation with associated shifts in osmoregulatory and mechanotransductive proteins that are likely to play important roles in intervertebral disc aging. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:788-798, 2018.
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Affiliation(s)
| | | | - Damien M. Laudier
- Dept. of Orthopaedics, Icahn School of Medicine at Mount Sinai, New York, NY
| | - Devina Purmessur
- Dept. of Biomedical Engineering, Ohio State University, Columbus, OH
| | - James C. Iatridis
- Dept. of Orthopaedics, Icahn School of Medicine at Mount Sinai, New York, NY
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90
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Gadok AK, Zhao C, Meriwether AI, Ferrati S, Rowley TG, Zoldan J, Smyth HDC, Stachowiak JC. The Display of Single-Domain Antibodies on the Surfaces of Connectosomes Enables Gap Junction-Mediated Drug Delivery to Specific Cell Populations. Biochemistry 2018; 57:81-90. [PMID: 28829120 PMCID: PMC5880529 DOI: 10.1021/acs.biochem.7b00688] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Gap junctions, transmembrane protein channels that directly connect the cytoplasm of neighboring cells and enable the exchange of molecules between cells, are a promising new frontier for therapeutic delivery. Specifically, cell-derived lipid vesicles that contain functional gap junction channels, termed Connectosomes, have recently been demonstrated to substantially increase the effectiveness of small molecule chemotherapeutics. However, because gap junctions are present in nearly all tissues, Connectosomes have no intrinsic ability to target specific cell types, which potentially limits their therapeutic effectiveness. To address this challenge, here we display targeting ligands consisting of single-domain antibodies on the surfaces of Connectosomes. We demonstrate that these targeted Connectosomes selectively interact with cells that express a model receptor, promoting the selective delivery of the chemotherapeutic doxorubicin to this target cell population. More generally, our approach has the potential to boost cytoplasmic delivery of diverse therapeutic molecules to specific cell populations while protecting off-target cells, a critical step toward realizing the therapeutic potential of gap junctions.
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Affiliation(s)
- Avinash K. Gadok
- Department of Biomedical Engineering, The University of Texas at Austin, Austin, TX
| | - Chi Zhao
- Department of Biomedical Engineering, The University of Texas at Austin, Austin, TX
| | - Amanda I. Meriwether
- Department of Biomedical Engineering, The University of Texas at Austin, Austin, TX
| | - Silvia Ferrati
- College of Pharmacy, The University of Texas at Austin, Austin, TX
| | - Tanner G. Rowley
- Department of Biomedical Engineering, The University of Texas at Austin, Austin, TX
| | - Janet Zoldan
- Department of Biomedical Engineering, The University of Texas at Austin, Austin, TX
| | - Hugh D. C. Smyth
- College of Pharmacy, The University of Texas at Austin, Austin, TX
| | - Jeanne C. Stachowiak
- Department of Biomedical Engineering, The University of Texas at Austin, Austin, TX
- Institute for Cellular and Molecular Biology, The University of Texas at Austin, Austin, TX
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91
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Li S, Bjelobaba I, Stojilkovic SS. Interactions of Pannexin1 channels with purinergic and NMDA receptor channels. BIOCHIMICA ET BIOPHYSICA ACTA. BIOMEMBRANES 2018; 1860:166-173. [PMID: 28389204 PMCID: PMC5628093 DOI: 10.1016/j.bbamem.2017.03.025] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/28/2016] [Revised: 03/28/2017] [Accepted: 03/29/2017] [Indexed: 12/31/2022]
Abstract
Pannexins are a three-member family of vertebrate plasma membrane spanning molecules that have homology to the invertebrate gap junction forming proteins, the innexins. However, pannexins do not form gap junctions but operate as plasma membrane channels. The best-characterized member of these proteins, Pannexin1 (Panx1) was suggested to be functionally associated with purinergic P2X and N-methyl-D-aspartate (NMDA) receptor channels. Activation of these receptor channels by their endogenous ligands leads to cross-activation of Panx1 channels. This in turn potentiates P2X and NMDA receptor channel signaling. Two potentiation concepts have been suggested: enhancement of the current responses and/or sustained receptor channel activation by ATP released through Panx1 pore and adenosine generated by ectonucleotidase-dependent dephosphorylation of ATP. Here we summarize the current knowledge and hypotheses about interactions of Panx1 channels with P2X and NMDA receptor channels. This article is part of a Special Issue entitled: Gap Junction Proteins edited by Jean Claude Herve.
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Affiliation(s)
- Shuo Li
- Tianjin Key Laboratory of Animal and Plant Resistance, College of Life Sciences, Tianjin Normal University, Tianjin 300387, China
| | - Ivana Bjelobaba
- Institute for Biological Research "Sinisa Stankovic", University of Belgrade, 11000 Belgrade, Serbia
| | - Stanko S Stojilkovic
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, NIH, Bethesda, MD 20892, USA.
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92
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Park J, Mazare A, Schneider H, von der Mark K, Fischer MJM, Schmuki P. Electric Field-Induced Osteogenic Differentiation on TiO2 Nanotubular Layer. Tissue Eng Part C Methods 2017; 22:809-21. [PMID: 27416901 DOI: 10.1089/ten.tec.2016.0182] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
On biocompatible implant surfaces, cellular behavior and fate of stem cells are determined not only by microenvironmental signals but also by electrochemical signals. The potential of electric fields (EFs) to stimulate bone growth and bone healing has been widely demonstrated, but the molecular mechanism linking EFs to osteogenic differentiation has remained elusive. Here we show that constant EFs triggered osteogenic induction of mesenchymal stem cells (MSCs) on a defined nanotubular TiO2 substrate. EFs stimulate the formation of plasma membrane protrusions and the transport of connexin 43 to these protrusions. Connexin 43 is required for the EF-induced lasting intracellular calcium increase, which rapidly propagates to neighboring cells by gap junctions. This enables simultaneous osteogenic induction following downstream calcineurin/CAMKII/NFAT signaling. We propose that connexin 43-mediated, EF-induced osteogenic differentiation of MSCs on a defined nanotubular titanium oxide surface may give new insight on therapeutic interventions for bone regeneration and tissue engineering approaches.
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Affiliation(s)
- Jung Park
- 1 Division of Molecular Pediatrics, Department of Pediatrics, University of Erlangen-Nürnberg , Erlangen, Germany
| | - Anca Mazare
- 2 Department of Materials Science, University of Erlangen-Nürnberg , Erlangen, Germany
| | - Holm Schneider
- 1 Division of Molecular Pediatrics, Department of Pediatrics, University of Erlangen-Nürnberg , Erlangen, Germany
| | - Klaus von der Mark
- 3 Department of Experimental Medicine I, Nikolaus-Fiebiger Center of Molecular Medicine, University of Erlangen-Nürnberg , Erlangen, Germany
| | - Michael J M Fischer
- 4 Institute of Physiology and Pathophysiology, University of Erlangen-Nürnberg , Erlangen, Germany
| | - Patrik Schmuki
- 2 Department of Materials Science, University of Erlangen-Nürnberg , Erlangen, Germany
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93
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Wang QH, Zhang S, Qin LM, Zhang WJ, Liu FH, Xu JQ, Ma YF, Teng KD. Yimu San improves obstetric ability of pregnant mice by increasing serum oxytocin levels and connexin 43 expression in uterine smooth muscle. J Zhejiang Univ Sci B 2017; 18:986-993. [PMID: 29119736 DOI: 10.1631/jzus.b1600289] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Prolonged farrowing remains one of the critical challenges in intensive pig farming. This study aims to explore the effects and mechanism of Yimu San (YMS), a Chinese veterinary medicine micro mist, on delivery ability with mouse models. Thirty-two pregnant mice were randomly divided into a control group and low-YMS, med-YMS, and high-YMS groups. The labor process time and stillbirth rate were recorded, the levels of serum oxytocin and prostaglandin E2 (PGE2) were measured with enzyme-linked immunosorbent assay (ELISA). Contractility measurements of the isolated uterus and the expression of connexin 43 (Cx43) in uterine smooth muscle were evaluated. The results showed that compared with the control group, the birth process time and stillbirth rate in the med-YMS and high-YMS groups were remarkably lower. The in vitro uterine contractions, levels of oxytocin, PGE2, and Cx43 in the med-YMS and high-YMS groups were significantly higher than those in the control group. The differences of the above measurements between the low-YMS group and the control group were not obvious. It can be speculated that YMS could significantly promote labor in pregnant mice by enhancing the levels of oxytocin, Cx43, and PGE2.
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Affiliation(s)
- Qi-Huan Wang
- College of Veterinary Medicine, China Agricultural University, Beijing 100193, China
| | - Shuang Zhang
- College of Veterinary Medicine, China Agricultural University, Beijing 100193, China
| | - Li-Meng Qin
- College of Veterinary Medicine, China Agricultural University, Beijing 100193, China
| | - Wen-Jun Zhang
- College of Veterinary Medicine, China Agricultural University, Beijing 100193, China
| | - Feng-Hua Liu
- College of Animal Science and Technology, Beijing University of Agriculture, Beijing 102206, China
| | - Jian-Qin Xu
- College of Veterinary Medicine, China Agricultural University, Beijing 100193, China
| | - Yun-Fei Ma
- College of Veterinary Medicine, China Agricultural University, Beijing 100193, China
| | - Ke-Dao Teng
- College of Veterinary Medicine, China Agricultural University, Beijing 100193, China
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94
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de Wolf E, van de Wiel J, Cook J, Dale N. Altered CO2 sensitivity of connexin26 mutant hemichannels in vitro. Physiol Rep 2017; 4:4/22/e13038. [PMID: 27884957 PMCID: PMC5357999 DOI: 10.14814/phy2.13038] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2016] [Revised: 10/19/2016] [Accepted: 10/21/2016] [Indexed: 12/17/2022] Open
Abstract
Connexin26 (Cx26) mutations underlie human pathologies ranging from hearing loss to keratitis ichthyosis deafness (KID) syndrome. Cx26 hemichannels are directly gated by CO2 and contribute to the chemosensory regulation of breathing. The KID syndrome mutation A88V is insensitive to CO2, and has a dominant negative action on the CO2 sensitivity of Cx26WT hemichannels, and reduces respiratory drive in humans. We have now examined the effect of further human mutations of Cx26 on its sensitivity to CO2 : Mutated Cx26 subunits, carrying one of A88S, N14K, N14Y, M34T, or V84L, were transiently expressed in HeLa cells. The CO2-dependence of hemichannel activity, and their ability to exert dominant negative actions on cells stably expressing Cx26WT, was quantified by a dye-loading assay. The KID syndrome mutation, N14K, abolished the sensitivity of Cx26 to CO2 Both N14Y and N14K exerted a powerful dominant negative action on the CO2 sensitivity of Cx26WT None of the other mutations (all recessive) had a dominant negative action. A88S shifted the affinity of Cx26 to slightly higher levels without reducing its ability to fully open to CO2 M34T did not change the affinity of Cx26 for CO2 but reduced its ability to open in response to CO2 V84L had no effect on the CO2-sensitivity of Cx26. Some pathological mutations of Cx26 can therefore alter the CO2 sensitivity of Cx26 hemichannels. The loss of CO2 sensitivity could contribute to pathology and consequent reduced respiratory drive could be an unrecognized comorbidity of these pathologies.
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Affiliation(s)
- Elizabeth de Wolf
- School of Life Sciences, University of Warwick, Coventry, United Kingdom
| | - Joseph van de Wiel
- School of Life Sciences, University of Warwick, Coventry, United Kingdom
| | - Jonathan Cook
- School of Life Sciences, University of Warwick, Coventry, United Kingdom
| | - Nicholas Dale
- School of Life Sciences, University of Warwick, Coventry, United Kingdom
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95
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Flores AF, Varela-Vazquez A, Mayan MD, Fonseca E. Expression of connexin 43 in the human hair follicle: emphasis on the connexin 43 protein levels in the bulge and through the keratinization process. J Cutan Pathol 2017; 45:8-15. [DOI: 10.1111/cup.13050] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2017] [Revised: 09/13/2017] [Accepted: 09/21/2017] [Indexed: 12/22/2022]
Affiliation(s)
- Angel Fernandez Flores
- Department of Cellular Pathology; Hospital El Bierzo; Ponferrada Spain
- Department of Cellular Pathology; Hospital de la Reina; Ponferrada Spain
- CellCOM-SB Group, Institute for Biomedical Research of A Coruña (INIBIC); University of A Coruña (UDC); A Coruña Spain
| | - Adrian Varela-Vazquez
- CellCOM-SB Group, Institute for Biomedical Research of A Coruña (INIBIC); University of A Coruña (UDC); A Coruña Spain
| | - Maria D. Mayan
- CellCOM-SB Group, Institute for Biomedical Research of A Coruña (INIBIC); University of A Coruña (UDC); A Coruña Spain
| | - Eduardo Fonseca
- CellCOM-SB Group, Institute for Biomedical Research of A Coruña (INIBIC); University of A Coruña (UDC); A Coruña Spain
- Department of Dermatology; University Hospital of A Coruña; A Coruña Spain
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96
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Zhang F, Bian Y, Huang L, Fan W. Association between connexin 40 and potassium voltage-gated channel subfamily A member 5 expression in the atrial myocytes of patients with atrial fibrillation. Exp Ther Med 2017; 14:5170-5176. [PMID: 29201233 DOI: 10.3892/etm.2017.5129] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2016] [Accepted: 03/17/2017] [Indexed: 12/24/2022] Open
Abstract
Structural and electrical remodeling within the atrium mediate the pathogenesis of atrial fibrillation (AF). Two key genes that sever a role in this remodeling are connexin 40 (Cx40) and potassium voltage-gated channel subfamily A member 5 (KCNA5), respectively. Electrical remodeling is considered to induce structural remodeling during AF. In the present study, the left atrial appendage section and atrial myocytes of patients with AF were evaluated. It was observed that Cx40 and KCNA5 mRNA (P<0.05) and protein (P<0.01) expression was significantly downregulated in AF compared with rheumatic heart disease. In addition, a positive correlation between the mRNA expression Cx40 and KCNA5 was observed in the atrial myocytes of patients with AF (P<0.05; r=0.42). The association between Cx40 and KCNA5 expression was subsequently investigated in primary cultured atrial myocytes using siRNA transfection. In atrial myocytes, downregulation of Cx40 inhibited the expression of KCNA5. Similarly, silencing of KCNA5 suppressed the expression of Cx40. These results indicate that synergistic regulation may occur between Cx40 and KCNA5 expression. Furthermore, the combined effects of electrical and structural remodeling in the atrial myocytes of patients with AF may contribute to the pathogenesis of AF.
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Affiliation(s)
- Fei Zhang
- Department of Cardiothoracic Surgery, Nanshan People's Hospital, Shenzhen, Guangdong 518052, P.R. China
| | - Yuhao Bian
- Department of Cardiothoracic Surgery, Nanshan People's Hospital, Shenzhen, Guangdong 518052, P.R. China.,Graduate School, Guangzhou Medical University, Guangzhou, Guangdong 510182, P.R. China
| | - Lei Huang
- Department of Cardiothoracic Surgery, Nanshan People's Hospital, Shenzhen, Guangdong 518052, P.R. China
| | - Wenbin Fan
- Department of Cardiothoracic Surgery, Nanshan People's Hospital, Shenzhen, Guangdong 518052, P.R. China
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97
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Umrani MR, Joglekar MV, Somerville Glover E, Wong W, Hardikar AA. Connexins and microRNAs: Interlinked players in regulating islet function? Islets 2017; 9:99-108. [PMID: 28686518 PMCID: PMC5624287 DOI: 10.1080/19382014.2017.1331192] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/15/2017] [Revised: 05/10/2017] [Accepted: 05/11/2017] [Indexed: 02/09/2023] Open
Abstract
Pancreatic β-cells are connected to neighboring endocrine cells through the adherin proteins and gap junctions. Connexin 36 (Cx36) is one of the most well-studied and abundantly expressed gap-junction proteins within rodent islets, which is important in coordinated insulin secretion. The expression of connexins is regulated at various levels and by several mechanisms; one of which is via microRNAs. In past 2 decades, microRNAs (miRNAs) have emerged as key molecules in developmental, physiologic and pathological processes. However, very few studies have demonstrated miRNA-mediated regulation of connexins. Even though there are no reports yet on miRNAs and Cx36; we envisage that considering the important role of connexins and microRNAs in insulin secretion, there would be common pathways interlinking these biomolecules. Here, we discuss the current literature on connexins and miRNAs specifically with reference to islet function.
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Affiliation(s)
- Malati R. Umrani
- National centre for cell science, Ganeshkhind, Pune University Campus, Pune, India
- Diabetes and Islet Biology Group, NHMRC Clinical Trials Centre, University of Sydney, Sydney, Australia
| | - Mugdha V. Joglekar
- Diabetes and Islet Biology Group, NHMRC Clinical Trials Centre, University of Sydney, Sydney, Australia
| | - Ella Somerville Glover
- Diabetes and Islet Biology Group, NHMRC Clinical Trials Centre, University of Sydney, Sydney, Australia
| | - Wilson Wong
- Diabetes and Islet Biology Group, NHMRC Clinical Trials Centre, University of Sydney, Sydney, Australia
| | - Anandwardhan A. Hardikar
- Diabetes and Islet Biology Group, NHMRC Clinical Trials Centre, University of Sydney, Sydney, Australia
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98
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Jacobsen NL, Pontifex TK, Li H, Solan JL, Lampe PD, Sorgen PL, Burt JM. Regulation of Cx37 channel and growth-suppressive properties by phosphorylation. J Cell Sci 2017; 130:3308-3321. [PMID: 28818996 DOI: 10.1242/jcs.202572] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2017] [Accepted: 08/08/2017] [Indexed: 12/24/2022] Open
Abstract
Growth suppression mediated by connexin 37 (Cx37; also known as GJA4) requires interaction between its C-terminus and functional pore-forming domain. Using rat insulinoma cells, we show that Cx37 induces cell death and cell cycle arrest, and slowed cell cycling. Whether differential phosphorylation might regulate intramolecular interactions, and consequently the growth-suppressive phenotype, is unknown. Protein kinase C inhibition increased the open state probability of low-conductance gap junction channels (GJChs) and reduced GJCh closed state probability. Substituting alanine at serine residues 275, 302 and 328 eliminated Cx37-induced cell death, supported proliferation and reduced the GJCh closed state probability. With additional alanine for serine substitutions at residues 285, 319, 321 and 325, Cx37-induced cell death was eliminated and the growth arrest period prolonged, and GJCh closed state probability was restored. With aspartate substitution at these seven sites, apoptosis was induced and the open state probability of large conductance GJChs (and hemichannels) was increased. These data suggest that differential phosphorylation of the C-terminus regulates channel conformation and, thereby, cell cycle progression and cell survival.
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Affiliation(s)
- Nicole L Jacobsen
- Department of Physiology, University of Arizona, Tucson, Arizona 85724-5051, USA
| | - Tasha K Pontifex
- Department of Physiology, University of Arizona, Tucson, Arizona 85724-5051, USA
| | - Hanjun Li
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE 68198-5870, USA
| | - Joell L Solan
- Translational Research Program, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA
| | - Paul D Lampe
- Translational Research Program, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA
| | - Paul L Sorgen
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE 68198-5870, USA
| | - Janis M Burt
- Department of Physiology, University of Arizona, Tucson, Arizona 85724-5051, USA
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99
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Abstract
PURPOSE OF REVIEW To discuss current knowledge on the role of connexins and pannexins in the musculoskeletal system. RECENT FINDINGS Connexins and pannexins are crucial for the development and maintenance of both bone and skeletal muscle. In bone, the presence of connexin and more recently of pannexin channels in osteoblasts, osteoclasts, and osteocytes has been described and shown to be essential for normal skeletal development and bone adaptation. In skeletal muscles, connexins and pannexins play important roles during development and regeneration through coordinated regulation of metabolic functions via cell-to-cell communication. Further, under pathological conditions, altered expression of these proteins can promote muscle atrophy and degeneration by stimulating inflammasome activity. In this review, we highlight the important roles of connexins and pannexins in the development, maintenance, and regeneration of musculoskeletal tissues, with emphasis on the mechanisms by which these molecules mediate chemical (e.g., ATP and prostaglandin E2) and physical (e.g., mechanical stimulation) stimuli that target the musculoskeletal system and their involvement in the pathophysiological changes in both genetic and acquired diseases.
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Affiliation(s)
- Lilian I Plotkin
- Department of Anatomy and Cell Biology, Indiana University School of Medicine, 635 Barnhill Drive, MS5045, Indianapolis, IN, 46202, USA.
- Roudebush Veterans Administration Medical Center, Indianapolis, Indiana, USA.
- Indiana Center for Musculoskeletal Health, Indianapolis, Indiana, USA.
| | - Hannah M Davis
- Department of Anatomy and Cell Biology, Indiana University School of Medicine, 635 Barnhill Drive, MS5045, Indianapolis, IN, 46202, USA
| | - Bruno A Cisterna
- Departamento de Fisiología, Pontificia Universidad Católica de Chile, Av. Alameda 340, Santiago, Chile
| | - Juan C Sáez
- Departamento de Fisiología, Pontificia Universidad Católica de Chile, Av. Alameda 340, Santiago, Chile.
- Centro Interdisciplinario de Neurociencias de Valparaíso, Valparaíso, Chile.
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The pivotal role of extracellular signal-regulated kinase in gap junction-mediated regulation of TXNIP. Cell Signal 2017; 38:116-126. [PMID: 28694028 DOI: 10.1016/j.cellsig.2017.07.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2017] [Revised: 07/06/2017] [Accepted: 07/06/2017] [Indexed: 12/27/2022]
Abstract
Gap junctions (GJs) play a major role in the control of cell structure, function, and metabolism. However, the molecular mechanisms involved are still poorly understood. Given that thioredoxin-interacting protein (TXNIP) regulates a broad range of cellular processes, we tested the possible involvement of TXNIP. Disruption of GJs with several chemical GJ inhibitors or connexin43 (Cx43) siRNA potently suppressed TXNIP, which was preceded by an activation of extracellular signal-regulated kinase (ERK). Inhibition of ERK or its upstream kinase with chemical inhibitors prevented the reduction of TXNIP. On the contrary, activation of ERK with mitogens or phosphatase inhibitors reproduced the suppressive effects of GJs. Further analysis revealed that dysfunction of GJs promoted TXNIP phosphorylation, ubiquitination, and degradation, whereas inhibition of ERK exerted the opposite effects. Moreover, inhibition of GJs elevated Glut1 and enhanced cell resistance to ER stress in a similar way to TXNIP downregulation. Collectively, our study thus characterizes ERK-mediated suppression of TXNIP as a presently unreported mechanism by which GJs regulate cell behaviors.
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