1
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Totland MZ, Knudsen LM, Rasmussen NL, Omori Y, Sørensen V, Elster VCW, Stenersen JM, Larsen M, Jensen CL, Zickfeldt Lade AA, Bruusgaard E, Basing S, Kryeziu K, Brech A, Aasen T, Lothe RA, Leithe E. The E3 ubiquitin ligase ITCH negatively regulates intercellular communication via gap junctions by targeting connexin43 for lysosomal degradation. Cell Mol Life Sci 2024; 81:171. [PMID: 38597989 PMCID: PMC11006747 DOI: 10.1007/s00018-024-05165-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2023] [Revised: 01/27/2024] [Accepted: 02/05/2024] [Indexed: 04/11/2024]
Abstract
Intercellular communication via gap junctions has a fundamental role in regulating cell growth and tissue homeostasis, and its dysregulation may be involved in cancer development and radio- and chemotherapy resistance. Connexin43 (Cx43) is the most ubiquitously expressed gap junction channel protein in human tissues. Emerging evidence indicates that dysregulation of the sorting of Cx43 to lysosomes is important in mediating the loss of Cx43-based gap junctions in cancer cells. However, the molecular basis underlying this process is currently poorly understood. Here, we identified the E3 ubiquitin ligase ITCH as a novel regulator of intercellular communication via gap junctions. We demonstrate that ITCH promotes loss of gap junctions in cervical cancer cells, which is associated with increased degradation of Cx43 in lysosomes. The data further indicate that ITCH interacts with and regulates Cx43 ubiquitination and that the ITCH-induced loss of Cx43-based gap junctions requires its catalytic HECT (homologous to E6-AP C-terminus) domain. The data also suggest that the ability of ITCH to efficiently promote loss of Cx43-based gap junctions and degradation of Cx43 depends on a functional PY (PPXY) motif in the C-terminal tail of Cx43. Together, these data provide new insights into the molecular basis underlying the degradation of Cx43 and have implications for the understanding of how intercellular communication via gap junctions is lost during cancer development.
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Affiliation(s)
- Max Zachrisson Totland
- Department of Molecular Oncology, Institute for Cancer Research, Oslo University Hospital, Oslo, NO-0424, Norway
| | - Lars Mørland Knudsen
- Department of Molecular Oncology, Institute for Cancer Research, Oslo University Hospital, Oslo, NO-0424, Norway
| | - Nikoline Lander Rasmussen
- Department of Molecular Oncology, Institute for Cancer Research, Oslo University Hospital, Oslo, NO-0424, Norway
- Centre for Molecular Medicine Norway, Faculty of Medicine, Oslo, Norway
| | - Yasufumi Omori
- Department of Molecular and Tumour Pathology, Akita University Graduate School of Medicine, Akita, 010-8543, Japan
| | - Vigdis Sørensen
- Department of Core Facilities, Institute for Cancer Research, Oslo University Hospital, Oslo, NO-0424, Norway
- Centre for Cancer Cell Reprogramming, Faculty of Medicine, University of Oslo, Oslo, 0379, Norway
| | - Vilde C Wivestad Elster
- Department of Molecular Oncology, Institute for Cancer Research, Oslo University Hospital, Oslo, NO-0424, Norway
| | - Jakob Mørkved Stenersen
- Department of Molecular Oncology, Institute for Cancer Research, Oslo University Hospital, Oslo, NO-0424, Norway
| | - Mathias Larsen
- Department of Molecular Oncology, Institute for Cancer Research, Oslo University Hospital, Oslo, NO-0424, Norway
| | - Caroline Lunder Jensen
- Department of Molecular Oncology, Institute for Cancer Research, Oslo University Hospital, Oslo, NO-0424, Norway
| | - Anna A Zickfeldt Lade
- Department of Molecular Oncology, Institute for Cancer Research, Oslo University Hospital, Oslo, NO-0424, Norway
| | - Emilie Bruusgaard
- Department of Molecular Oncology, Institute for Cancer Research, Oslo University Hospital, Oslo, NO-0424, Norway
| | - Sebastian Basing
- Department of Molecular Oncology, Institute for Cancer Research, Oslo University Hospital, Oslo, NO-0424, Norway
| | - Kushtrim Kryeziu
- Department of Molecular Oncology, Institute for Cancer Research, Oslo University Hospital, Oslo, NO-0424, Norway
| | - Andreas Brech
- Department of Core Facilities, Institute for Cancer Research, Oslo University Hospital, Oslo, NO-0424, Norway
- Department of Molecular Cell Biology, Institute for Cancer Research, Oslo University Hospital, Oslo, 0379, Norway
- Department of Biosciences, Faculty of Mathematics and Natural Sciences, Oslo, 0316, Norway
| | - Trond Aasen
- Patologia Molecular Translacional, Vall d'Hebron Institut de Recerca (VHIR), Vall d'Hebron Hospital Universitari, Vall d'Hebron Barcelona Hospital Campus, Passeig Vall d'Hebron 119-129, Barcelona, 08035, Spain
| | - Ragnhild A Lothe
- Department of Molecular Oncology, Institute for Cancer Research, Oslo University Hospital, Oslo, NO-0424, Norway
- Department of Biosciences, Faculty of Mathematics and Natural Sciences, Oslo, 0316, Norway
- Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, Oslo, 0317, Norway
| | - Edward Leithe
- Department of Molecular Oncology, Institute for Cancer Research, Oslo University Hospital, Oslo, NO-0424, Norway
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Xu K, Chen S, Bai X, Xie L, Qiu Y, Liu X, Wang X, Kong W, Sun Y. Degradation of cochlear Connexin26 accelerate the development of age-related hearing loss. Aging Cell 2023; 22:e13973. [PMID: 37681746 PMCID: PMC10652327 DOI: 10.1111/acel.13973] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2023] [Revised: 08/03/2023] [Accepted: 08/15/2023] [Indexed: 09/09/2023] Open
Abstract
The GJB2 gene, encoding Connexin26 (Cx26), is one of the most common causes of inherited deafness. Clinically, mutations in GJB2 cause congenital deafness or late-onset progressive hearing loss. Recently, it has been reported that Cx26 haploid deficiency accelerates the development of age-related hearing loss (ARHL). However, the roles of cochlear Cx26 in the hearing function of aged animals remain unclear. In this study, we revealed that the Cx26 expression was significantly reduced in the cochleae of aged mice, and further explored the underlying molecular mechanism for Cx26 degradation. Immunofluorescence co-localization results showed that Cx26 was internalized and degraded by lysosomes, which might be one of the important ways for Cx26 degradation in the cochlea of aged mice. Currently, whether the degradation of Cx26 in the cochlea leads directly to ARHL, as well as the mechanism of Cx26 degradation-related hearing loss are still unclear. To address these questions, we generated mice with Cx26 knockout in the adult cochlea as a model for the natural degradation of Cx26. Auditory brainstem response (ABR) results showed that Cx26 knockout mice exhibited high-frequency hearing loss, which gradually progressed over time. Pathological examination also revealed the degeneration of hair cells and spiral ganglions, which is similar to the phenotype of ARHL. In summary, our findings suggest that degradation of Cx26 in the cochlea accelerates the occurrence of ARHL, which may be a novel mechanism of ARHL.
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Affiliation(s)
- Kai Xu
- Department of Otorhinolaryngology, Union Hospital, Tongji Medical CollegeHuazhong University of Science and TechnologyWuhanChina
| | - Sen Chen
- Department of Otorhinolaryngology, Union Hospital, Tongji Medical CollegeHuazhong University of Science and TechnologyWuhanChina
| | - Xue Bai
- Department of Otorhinolaryngology, Union Hospital, Tongji Medical CollegeHuazhong University of Science and TechnologyWuhanChina
| | - Le Xie
- Department of Otorhinolaryngology, Union Hospital, Tongji Medical CollegeHuazhong University of Science and TechnologyWuhanChina
| | - Yue Qiu
- Department of Otorhinolaryngology, Union Hospital, Tongji Medical CollegeHuazhong University of Science and TechnologyWuhanChina
| | - Xiao‐zhou Liu
- Department of Otorhinolaryngology, Union Hospital, Tongji Medical CollegeHuazhong University of Science and TechnologyWuhanChina
| | - Xiao‐hui Wang
- Department of Otorhinolaryngology, Union Hospital, Tongji Medical CollegeHuazhong University of Science and TechnologyWuhanChina
| | - Wei‐jia Kong
- Department of Otorhinolaryngology, Union Hospital, Tongji Medical CollegeHuazhong University of Science and TechnologyWuhanChina
| | - Yu Sun
- Department of Otorhinolaryngology, Union Hospital, Tongji Medical CollegeHuazhong University of Science and TechnologyWuhanChina
- Hubei Province Key Laboratory of Oral and Maxillofacial Development and RegenerationWuhanChina
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3
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Totland MZ, Omori Y, Sørensen V, Kryeziu K, Aasen T, Brech A, Leithe E. Endocytic trafficking of connexins in cancer pathogenesis. Biochim Biophys Acta Mol Basis Dis 2023:166812. [PMID: 37454772 DOI: 10.1016/j.bbadis.2023.166812] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2023] [Revised: 06/26/2023] [Accepted: 07/11/2023] [Indexed: 07/18/2023]
Abstract
Gap junctions are specialized regions of the plasma membrane containing clusters of channels that provide for the diffusion of ions and small molecules between adjacent cells. A fundamental role of gap junctions is to coordinate the functions of cells in tissues. Cancer pathogenesis is usually associated with loss of intercellular communication mediated by gap junctions, which may affect tumor growth and the response to radio- and chemotherapy. Gap junction channels consist of integral membrane proteins termed connexins. In addition to their canonical roles in cell-cell communication, connexins modulate a range of signal transduction pathways via interactions with proteins such as β-catenin, c-Src, and PTEN. Consequently, connexins can regulate cellular processes such as cell growth, migration, and differentiation through both channel-dependent and independent mechanisms. Gap junctions are dynamic plasma membrane entities, and by modulating the rate at which connexins undergo endocytosis and sorting to lysosomes for degradation, cells rapidly adjust the level of gap junctions in response to alterations in the intracellular or extracellular milieu. Current experimental evidence indicates that aberrant trafficking of connexins in the endocytic system is intrinsically involved in mediating the loss of gap junctions during carcinogenesis. This review highlights the role played by the endocytic system in controlling connexin degradation, and consequently gap junction levels, and discusses how dysregulation of these processes contributes to the loss of gap junctions during cancer development. We also discuss the therapeutic implications of aberrant endocytic trafficking of connexins in cancer cells.
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Affiliation(s)
| | - Yasufumi Omori
- Department of Molecular and Tumour Pathology, Akita University Graduate School of Medicine, Akita, Japan
| | | | | | - Trond Aasen
- Patologia Molecular Translacional, Vall d'Hebron Institut de Recerca (VHIR), Vall d'Hebron Hospital Universitari, Vall d'Hebron Barcelona Hospital Campus, Passeig Vall d'Hebron, Barcelona, Spain
| | - Andreas Brech
- Department of Molecular Cell Biology, Institute for Cancer Research, Oslo University Hospital, Oslo, Norway; Centre for Cancer Cell Reprogramming, Faculty of Medicine, University of Oslo, Oslo, Norway; Section for Physiology and Cell Biology, Department of Biosciences, Faculty of Mathematics and Natural Sciences, University of Oslo, Oslo, Norway
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Won DH, Hwang DB, Kim C, Kang M, Jeon Y, Park YI, Che JH, Yun JW. Genotoxic carcinogen 7,12-dimethylbenz[a]anthracene inhibits gap junction intercellular communication through post-transcriptional and post-translational processing involved in connexin 43 stability. Food Chem Toxicol 2023; 174:113695. [PMID: 36863560 DOI: 10.1016/j.fct.2023.113695] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2023] [Revised: 02/22/2023] [Accepted: 02/25/2023] [Indexed: 03/04/2023]
Abstract
Gap junctional intercellular communication (GJIC) is composed of connexin (Cx) and plays an important role in maintaining intracellular homeostasis. Loss of GJIC is involved in the early stages of cancer pathways of non-genotoxic carcinogens; however, the effect of genotoxic carcinogens, including polycyclic aromatic hydrocarbons (PAHs), on GJIC function remains unclear. Therefore, we determined whether and how a representative PAH 7,12-dimethylbenz[a]anthracene (DMBA) suppresses GJIC in WB-F344 cells. First, DMBA significantly inhibited GJIC and dose-dependently reduced Cx43 protein and mRNA expression. In contrast, Cx43 promoter activity was upregulated after DMBA treatment via the induction of specificity protein 1 and hepatocyte nuclear factor 3β, indicating that the promoter-independent loss of Cx43 mRNA can be associated with the inhibition of mRNA stability, which was verified by actinomycin D assay. In addition to a decrease in mRNA stability involved in human antigen R, we also observed DMBA-induced acceleration of Cx43 protein degradation, which was closely related to the loss of GJIC through Cx43 phosphorylation via MAPK activation. In conclusion, the genotoxic carcinogen DMBA suppresses GJIC by inhibiting post-transcriptional and post-translational processing of Cx43. Our findings suggest that the GJIC assay is an efficient short-term screening test for predicting the carcinogenic potential of genotoxic carcinogens.
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Affiliation(s)
- Dong-Hoon Won
- Department of Biotechnology, The Catholic University of Korea, Bucheon, 14662, South Korea
| | - Da-Bin Hwang
- Department of Biotechnology, The Catholic University of Korea, Bucheon, 14662, South Korea
| | - Changuk Kim
- Department of Biotechnology, The Catholic University of Korea, Bucheon, 14662, South Korea
| | - MinHwa Kang
- Laboratory of Veterinary Toxicology, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Seoul, 08826, Republic of Korea
| | - Young Jeon
- Laboratory of Veterinary Toxicology, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Seoul, 08826, Republic of Korea
| | - Yong Il Park
- Department of Biotechnology, The Catholic University of Korea, Bucheon, 14662, South Korea
| | - Jeong-Hwan Che
- Biomedical Center for Animal Resource and Development, Seoul National University College of Medicine, Seoul, 03080, South Korea
| | - Jun-Won Yun
- Laboratory of Veterinary Toxicology, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Seoul, 08826, Republic of Korea.
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El-Hajjar L, Saliba J, Karam M, Shaito A, El Hajj H, El-Sabban M. Ubiquitin-Related Modifier 1 (URM-1) Modulates Cx43 in Breast Cancer Cell Lines. Int J Mol Sci 2023; 24:ijms24032958. [PMID: 36769280 PMCID: PMC9917400 DOI: 10.3390/ijms24032958] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2022] [Revised: 12/23/2022] [Accepted: 12/28/2022] [Indexed: 02/05/2023] Open
Abstract
Gap-junction-forming connexins are exquisitely regulated by post-translational modifications (PTMs). In particular, the PTM of connexin 43 (Cx43), a tumor suppressor protein, regulates its turnover and activity. Here, we investigated the interaction of Cx43 with the ubiquitin-related modifier 1 (URM-1) protein and its impact on tumor progression in two breast cancer cell lines, highly metastatic triple-negative MDA-MB-231 and luminal breast cancer MCF-7 cell lines. To evaluate the subsequent modulation of Cx43 levels, URM-1 was downregulated in these cells. The transcriptional levels of epithelial-to-mesenchymal transition (EMT) markers and the metastatic phenotype were assessed. We demonstrated that Cx43 co-localizes and interacts with URM-1, and URMylated Cx43 was accentuated upon cellular stress. The significant upregulation of small ubiquitin-like modifier-1 (SUMO-1) was also observed. In cells with downregulated URM-1, Cx43 expression significantly decreased, and SUMOylation by SUMO-1 was affected. The concomitant expression of EMT markers increased, leading to increased proliferation, migration, and invasion potential. Inversely, the upregulation of URM-1 increased Cx43 expression and reversed EMT-induced processes, underpinning a role for this PTM in the observed phenotypes. This study proposes that the URMylation of Cx43 in breast cancer cells regulates its tumor suppression properties and contributes to breast cancer cell malignancy.
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Affiliation(s)
- Layal El-Hajjar
- Department of Anatomy, Cell Biology and Physiological Sciences, Faculty of Medicine, American University of Beirut, Beirut P.O. Box 11-0236, Lebanon
| | - Jessica Saliba
- Department of Biology, Faculty of Sciences, Lebanese University, Beirut P.O. Box 90656, Lebanon
- Department of Public Health, Faculty of Health Sciences, University of Balamand, Beirut P.O. Box 100, Lebanon
| | - Mario Karam
- Department of Anatomy, Cell Biology and Physiological Sciences, Faculty of Medicine, American University of Beirut, Beirut P.O. Box 11-0236, Lebanon
| | - Abdullah Shaito
- Biomedical Research Center, Qatar University Doha, Doha P.O. Box 2713, Qatar
| | - Hiba El Hajj
- Department of Experimental Pathology, Immunology and Microbiology, Faculty of Medicine, American University of Beirut, Beirut P.O. Box 11-0236, Lebanon
| | - Marwan El-Sabban
- Department of Anatomy, Cell Biology and Physiological Sciences, Faculty of Medicine, American University of Beirut, Beirut P.O. Box 11-0236, Lebanon
- Correspondence: ; Tel.: +961-(1)-350000 (ext. 4765)
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Applicability of Scrape Loading-Dye Transfer Assay for Non-Genotoxic Carcinogen Testing. Int J Mol Sci 2021; 22:ijms22168977. [PMID: 34445682 PMCID: PMC8396440 DOI: 10.3390/ijms22168977] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Revised: 07/30/2021] [Accepted: 07/31/2021] [Indexed: 12/27/2022] Open
Abstract
Dysregulation of gap junction intercellular communication (GJIC) is recognized as one of the key hallmarks for identifying non-genotoxic carcinogens (NGTxC). Currently, there is a demand for in vitro assays addressing the gap junction hallmark, which would have the potential to eventually become an integral part of an integrated approach to the testing and assessment (IATA) of NGTxC. The scrape loading-dye transfer (SL-DT) technique is a simple assay for the functional evaluation of GJIC in various in vitro cultured mammalian cells and represents an interesting candidate assay. Out of the various techniques for evaluating GJIC, the SL-DT assay has been used frequently to assess the effects of various chemicals on GJIC in toxicological and tumor promotion research. In this review, we systematically searched the existing literature to gather papers assessing GJIC using the SL-DT assay in a rat liver epithelial cell line, WB-F344, after treating with chemicals, especially environmental and food toxicants, drugs, reproductive-, cardio- and neuro-toxicants and chemical tumor promoters. We discuss findings derived from the SL-DT assay with the known knowledge about the tumor-promoting activity and carcinogenicity of the assessed chemicals to evaluate the predictive capacity of the SL-DT assay in terms of its sensitivity, specificity and accuracy for identifying carcinogens. These data represent important information with respect to the applicability of the SL-DT assay for the testing of NGTxC within the IATA framework.
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Leroy K, Pieters A, Tabernilla A, Cooreman A, Van Campenhout R, Cogliati B, Vinken M. Targeting gap junctional intercellular communication by hepatocarcinogenic compounds. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH. PART B, CRITICAL REVIEWS 2020; 23:255-275. [PMID: 32568623 DOI: 10.1080/10937404.2020.1781010] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Gap junctions in liver, as in other organs, play a critical role in tissue homeostasis. Inherently, these cellular constituents are major targets for systemic toxicity and diseases, including cancer. This review provides an overview of chemicals that compromise liver gap junctions, in particular biological toxins, organic solvents, pesticides, pharmaceuticals, peroxides, metals and phthalates. The focus in this review is placed upon the mechanistic scenarios that underlie these adverse effects. Further, the potential use of gap junctional activity as an in vitro biomarker to identify non-genotoxic hepatocarcinogenic chemicals is discussed.
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Affiliation(s)
- Kaat Leroy
- Department of In Vitro Toxicology and Dermato-Cosmetology, Vrije Universiteit Brussel , Brussels, Belgium
| | - Alanah Pieters
- Department of In Vitro Toxicology and Dermato-Cosmetology, Vrije Universiteit Brussel , Brussels, Belgium
| | - Andrés Tabernilla
- Department of In Vitro Toxicology and Dermato-Cosmetology, Vrije Universiteit Brussel , Brussels, Belgium
| | - Axelle Cooreman
- Department of In Vitro Toxicology and Dermato-Cosmetology, Vrije Universiteit Brussel , Brussels, Belgium
| | - Raf Van Campenhout
- Department of In Vitro Toxicology and Dermato-Cosmetology, Vrije Universiteit Brussel , Brussels, Belgium
| | - Bruno Cogliati
- Department of Pathology, School of Veterinary Medicine and Animal Science, University of São Paulo, Cidade Universitária , São Paulo, Brazil
| | - Mathieu Vinken
- Department of In Vitro Toxicology and Dermato-Cosmetology, Vrije Universiteit Brussel , Brussels, Belgium
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Sánchez OF, Rodríguez AV, Velasco-España JM, Murillo LC, Sutachan JJ, Albarracin SL. Role of Connexins 30, 36, and 43 in Brain Tumors, Neurodegenerative Diseases, and Neuroprotection. Cells 2020; 9:E846. [PMID: 32244528 PMCID: PMC7226843 DOI: 10.3390/cells9040846] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2019] [Revised: 02/15/2020] [Accepted: 02/24/2020] [Indexed: 02/07/2023] Open
Abstract
Gap junction (GJ) channels and their connexins (Cxs) are complex proteins that have essential functions in cell communication processes in the central nervous system (CNS). Neurons, astrocytes, oligodendrocytes, and microglial cells express an extraordinary repertory of Cxs that are important for cell to cell communication and diffusion of metabolites, ions, neurotransmitters, and gliotransmitters. GJs and Cxs not only contribute to the normal function of the CNS but also the pathological progress of several diseases, such as cancer and neurodegenerative diseases. Besides, they have important roles in mediating neuroprotection by internal or external molecules. However, regulation of Cx expression by epigenetic mechanisms has not been fully elucidated. In this review, we provide an overview of the known mechanisms that regulate the expression of the most abundant Cxs in the central nervous system, Cx30, Cx36, and Cx43, and their role in brain cancer, CNS disorders, and neuroprotection. Initially, we focus on describing the Cx gene structure and how this is regulated by epigenetic mechanisms. Then, the posttranslational modifications that mediate the activity and stability of Cxs are reviewed. Finally, the role of GJs and Cxs in glioblastoma, Alzheimer's, Parkinson's, and Huntington's diseases, and neuroprotection are analyzed with the aim of shedding light in the possibility of using Cx regulators as potential therapeutic molecules.
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Affiliation(s)
- Oscar F. Sánchez
- Department of Nutrition and Biochemistry, Pontificia Universidad Javeriana, 110911 Bogota, Colombia; (A.V.R.); (J.M.V.-E.); (L.C.M.); (J.-J.S.)
| | | | | | | | | | - Sonia-Luz Albarracin
- Department of Nutrition and Biochemistry, Pontificia Universidad Javeriana, 110911 Bogota, Colombia; (A.V.R.); (J.M.V.-E.); (L.C.M.); (J.-J.S.)
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Totland MZ, Rasmussen NL, Knudsen LM, Leithe E. Regulation of gap junction intercellular communication by connexin ubiquitination: physiological and pathophysiological implications. Cell Mol Life Sci 2020; 77:573-591. [PMID: 31501970 PMCID: PMC7040059 DOI: 10.1007/s00018-019-03285-0] [Citation(s) in RCA: 89] [Impact Index Per Article: 22.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2019] [Revised: 08/10/2019] [Accepted: 08/16/2019] [Indexed: 12/15/2022]
Abstract
Gap junctions consist of arrays of intercellular channels that enable adjacent cells to communicate both electrically and metabolically. Gap junctions have a wide diversity of physiological functions, playing critical roles in both excitable and non-excitable tissues. Gap junction channels are formed by integral membrane proteins called connexins. Inherited or acquired alterations in connexins are associated with numerous diseases, including heart failure, neuropathologies, deafness, skin disorders, cataracts and cancer. Gap junctions are highly dynamic structures and by modulating the turnover rate of connexins, cells can rapidly alter the number of gap junction channels at the plasma membrane in response to extracellular or intracellular cues. Increasing evidence suggests that ubiquitination has important roles in the regulation of endoplasmic reticulum-associated degradation of connexins as well as in the modulation of gap junction endocytosis and post-endocytic sorting of connexins to lysosomes. In recent years, researchers have also started to provide insights into the physiological roles of connexin ubiquitination in specific tissue types. This review provides an overview of the advances made in understanding the roles of connexin ubiquitination in the regulation of gap junction intercellular communication and discusses the emerging physiological and pathophysiological implications of these processes.
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Affiliation(s)
- Max Zachrisson Totland
- Department of Molecular Oncology, Institute for Cancer Research, Oslo University Hospital, 0424, Oslo, Norway
- K.G. Jebsen Colorectal Cancer Research Centre, Oslo University Hospital, Oslo, Norway
| | - Nikoline Lander Rasmussen
- Department of Molecular Oncology, Institute for Cancer Research, Oslo University Hospital, 0424, Oslo, Norway
- K.G. Jebsen Colorectal Cancer Research Centre, Oslo University Hospital, Oslo, Norway
- Department of Medical Biology, University of Tromsø, Tromsø, Norway
| | - Lars Mørland Knudsen
- Department of Molecular Oncology, Institute for Cancer Research, Oslo University Hospital, 0424, Oslo, Norway
- K.G. Jebsen Colorectal Cancer Research Centre, Oslo University Hospital, Oslo, Norway
| | - Edward Leithe
- Department of Molecular Oncology, Institute for Cancer Research, Oslo University Hospital, 0424, Oslo, Norway.
- K.G. Jebsen Colorectal Cancer Research Centre, Oslo University Hospital, Oslo, Norway.
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Bell CL, Shakespeare TI, Smith AR, Murray SA. Visualization of Annular Gap Junction Vesicle Processing: The Interplay Between Annular Gap Junctions and Mitochondria. Int J Mol Sci 2018; 20:ijms20010044. [PMID: 30583492 PMCID: PMC6337258 DOI: 10.3390/ijms20010044] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2018] [Revised: 12/15/2018] [Accepted: 12/20/2018] [Indexed: 11/16/2022] Open
Abstract
It is becoming clear that in addition to gap junctions playing a role in cell⁻cell communication, gap junction proteins (connexins) located in cytoplasmic compartments may have other important functions. Mitochondrial connexin 43 (Cx43) is increased after ischemic preconditioning and has been suggested to play a protective role in the heart. How Cx43 traffics to the mitochondria and the interactions of mitochondria with other Cx43-containing structures are unclear. In this study, immunocytochemical, super-resolution, and transmission electron microscopy were used to detect cytoplasmic Cx43-containing structures and to demonstrate their interactions with other cytoplasmic organelles. The most prominent cytoplasmic Cx43-containing structures-annular gap junctions-were demonstrated to form intimate associations with lysosomes as well as with mitochondria. Surprisingly, the frequency of associations between mitochondria and annular gap junctions was greater than that between lysosomes and annular gap junctions. The benefits of annular gap junction/mitochondrial associations are not known. However, it is tempting to suggest, among other possibilities, that the contact between annular gap junction vesicles and mitochondria facilitates Cx43 delivery to the mitochondria. Furthermore, it points to the need for investigating annular gap junctions as more than only vesicles destined for degradation.
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Affiliation(s)
- Cheryl L Bell
- Department of Cell Biology, School of Medicine, University of Pittsburgh, Pittsburgh, PA 15261, USA.
| | | | - Amber R Smith
- Department of Cell Biology, School of Medicine, University of Pittsburgh, Pittsburgh, PA 15261, USA.
| | - Sandra A Murray
- Department of Cell Biology, School of Medicine, University of Pittsburgh, Pittsburgh, PA 15261, USA.
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Leybaert L, Lampe PD, Dhein S, Kwak BR, Ferdinandy P, Beyer EC, Laird DW, Naus CC, Green CR, Schulz R. Connexins in Cardiovascular and Neurovascular Health and Disease: Pharmacological Implications. Pharmacol Rev 2017; 69:396-478. [PMID: 28931622 PMCID: PMC5612248 DOI: 10.1124/pr.115.012062] [Citation(s) in RCA: 171] [Impact Index Per Article: 24.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Connexins are ubiquitous channel forming proteins that assemble as plasma membrane hemichannels and as intercellular gap junction channels that directly connect cells. In the heart, gap junction channels electrically connect myocytes and specialized conductive tissues to coordinate the atrial and ventricular contraction/relaxation cycles and pump function. In blood vessels, these channels facilitate long-distance endothelial cell communication, synchronize smooth muscle cell contraction, and support endothelial-smooth muscle cell communication. In the central nervous system they form cellular syncytia and coordinate neural function. Gap junction channels are normally open and hemichannels are normally closed, but pathologic conditions may restrict gap junction communication and promote hemichannel opening, thereby disturbing a delicate cellular communication balance. Until recently, most connexin-targeting agents exhibited little specificity and several off-target effects. Recent work with peptide-based approaches has demonstrated improved specificity and opened avenues for a more rational approach toward independently modulating the function of gap junctions and hemichannels. We here review the role of connexins and their channels in cardiovascular and neurovascular health and disease, focusing on crucial regulatory aspects and identification of potential targets to modify their function. We conclude that peptide-based investigations have raised several new opportunities for interfering with connexins and their channels that may soon allow preservation of gap junction communication, inhibition of hemichannel opening, and mitigation of inflammatory signaling.
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Affiliation(s)
- Luc Leybaert
- Physiology Group, Department of Basic Medical Sciences, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium (L.L.); Translational Research Program, Fred Hutchinson Cancer Research Center, Seattle, Washington (P.D.L.); Institute for Pharmacology, University of Leipzig, Leipzig, Germany (S.D.); Department of Pathology and Immunology, Department of Medical Specialization-Cardiology, University of Geneva, Geneva, Switzerland (B.R.K.); Department of Pharmacology and Pharmacotherapy, Semmelweis University, Budapest, Hungary (P.F.); Pharmahungary Group, Szeged, Hungary (P.F.); Department of Pediatrics, University of Chicago, Chicago, Illinois (E.C.B.); Department of Anatomy and Cell Biology, University of Western Ontario, Dental Science Building, London, Ontario, Canada (D.W.L.); Cellular and Physiological Sciences, Faculty of Medicine, The University of British Columbia, Vancouver, British Columbia, Canada (C.C.N.); Department of Ophthalmology and The New Zealand National Eye Centre, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand (C.R.G.); and Physiologisches Institut, Justus-Liebig-Universität Giessen, Giessen, Germany (R.S.)
| | - Paul D Lampe
- Physiology Group, Department of Basic Medical Sciences, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium (L.L.); Translational Research Program, Fred Hutchinson Cancer Research Center, Seattle, Washington (P.D.L.); Institute for Pharmacology, University of Leipzig, Leipzig, Germany (S.D.); Department of Pathology and Immunology, Department of Medical Specialization-Cardiology, University of Geneva, Geneva, Switzerland (B.R.K.); Department of Pharmacology and Pharmacotherapy, Semmelweis University, Budapest, Hungary (P.F.); Pharmahungary Group, Szeged, Hungary (P.F.); Department of Pediatrics, University of Chicago, Chicago, Illinois (E.C.B.); Department of Anatomy and Cell Biology, University of Western Ontario, Dental Science Building, London, Ontario, Canada (D.W.L.); Cellular and Physiological Sciences, Faculty of Medicine, The University of British Columbia, Vancouver, British Columbia, Canada (C.C.N.); Department of Ophthalmology and The New Zealand National Eye Centre, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand (C.R.G.); and Physiologisches Institut, Justus-Liebig-Universität Giessen, Giessen, Germany (R.S.)
| | - Stefan Dhein
- Physiology Group, Department of Basic Medical Sciences, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium (L.L.); Translational Research Program, Fred Hutchinson Cancer Research Center, Seattle, Washington (P.D.L.); Institute for Pharmacology, University of Leipzig, Leipzig, Germany (S.D.); Department of Pathology and Immunology, Department of Medical Specialization-Cardiology, University of Geneva, Geneva, Switzerland (B.R.K.); Department of Pharmacology and Pharmacotherapy, Semmelweis University, Budapest, Hungary (P.F.); Pharmahungary Group, Szeged, Hungary (P.F.); Department of Pediatrics, University of Chicago, Chicago, Illinois (E.C.B.); Department of Anatomy and Cell Biology, University of Western Ontario, Dental Science Building, London, Ontario, Canada (D.W.L.); Cellular and Physiological Sciences, Faculty of Medicine, The University of British Columbia, Vancouver, British Columbia, Canada (C.C.N.); Department of Ophthalmology and The New Zealand National Eye Centre, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand (C.R.G.); and Physiologisches Institut, Justus-Liebig-Universität Giessen, Giessen, Germany (R.S.)
| | - Brenda R Kwak
- Physiology Group, Department of Basic Medical Sciences, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium (L.L.); Translational Research Program, Fred Hutchinson Cancer Research Center, Seattle, Washington (P.D.L.); Institute for Pharmacology, University of Leipzig, Leipzig, Germany (S.D.); Department of Pathology and Immunology, Department of Medical Specialization-Cardiology, University of Geneva, Geneva, Switzerland (B.R.K.); Department of Pharmacology and Pharmacotherapy, Semmelweis University, Budapest, Hungary (P.F.); Pharmahungary Group, Szeged, Hungary (P.F.); Department of Pediatrics, University of Chicago, Chicago, Illinois (E.C.B.); Department of Anatomy and Cell Biology, University of Western Ontario, Dental Science Building, London, Ontario, Canada (D.W.L.); Cellular and Physiological Sciences, Faculty of Medicine, The University of British Columbia, Vancouver, British Columbia, Canada (C.C.N.); Department of Ophthalmology and The New Zealand National Eye Centre, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand (C.R.G.); and Physiologisches Institut, Justus-Liebig-Universität Giessen, Giessen, Germany (R.S.)
| | - Peter Ferdinandy
- Physiology Group, Department of Basic Medical Sciences, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium (L.L.); Translational Research Program, Fred Hutchinson Cancer Research Center, Seattle, Washington (P.D.L.); Institute for Pharmacology, University of Leipzig, Leipzig, Germany (S.D.); Department of Pathology and Immunology, Department of Medical Specialization-Cardiology, University of Geneva, Geneva, Switzerland (B.R.K.); Department of Pharmacology and Pharmacotherapy, Semmelweis University, Budapest, Hungary (P.F.); Pharmahungary Group, Szeged, Hungary (P.F.); Department of Pediatrics, University of Chicago, Chicago, Illinois (E.C.B.); Department of Anatomy and Cell Biology, University of Western Ontario, Dental Science Building, London, Ontario, Canada (D.W.L.); Cellular and Physiological Sciences, Faculty of Medicine, The University of British Columbia, Vancouver, British Columbia, Canada (C.C.N.); Department of Ophthalmology and The New Zealand National Eye Centre, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand (C.R.G.); and Physiologisches Institut, Justus-Liebig-Universität Giessen, Giessen, Germany (R.S.)
| | - Eric C Beyer
- Physiology Group, Department of Basic Medical Sciences, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium (L.L.); Translational Research Program, Fred Hutchinson Cancer Research Center, Seattle, Washington (P.D.L.); Institute for Pharmacology, University of Leipzig, Leipzig, Germany (S.D.); Department of Pathology and Immunology, Department of Medical Specialization-Cardiology, University of Geneva, Geneva, Switzerland (B.R.K.); Department of Pharmacology and Pharmacotherapy, Semmelweis University, Budapest, Hungary (P.F.); Pharmahungary Group, Szeged, Hungary (P.F.); Department of Pediatrics, University of Chicago, Chicago, Illinois (E.C.B.); Department of Anatomy and Cell Biology, University of Western Ontario, Dental Science Building, London, Ontario, Canada (D.W.L.); Cellular and Physiological Sciences, Faculty of Medicine, The University of British Columbia, Vancouver, British Columbia, Canada (C.C.N.); Department of Ophthalmology and The New Zealand National Eye Centre, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand (C.R.G.); and Physiologisches Institut, Justus-Liebig-Universität Giessen, Giessen, Germany (R.S.)
| | - Dale W Laird
- Physiology Group, Department of Basic Medical Sciences, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium (L.L.); Translational Research Program, Fred Hutchinson Cancer Research Center, Seattle, Washington (P.D.L.); Institute for Pharmacology, University of Leipzig, Leipzig, Germany (S.D.); Department of Pathology and Immunology, Department of Medical Specialization-Cardiology, University of Geneva, Geneva, Switzerland (B.R.K.); Department of Pharmacology and Pharmacotherapy, Semmelweis University, Budapest, Hungary (P.F.); Pharmahungary Group, Szeged, Hungary (P.F.); Department of Pediatrics, University of Chicago, Chicago, Illinois (E.C.B.); Department of Anatomy and Cell Biology, University of Western Ontario, Dental Science Building, London, Ontario, Canada (D.W.L.); Cellular and Physiological Sciences, Faculty of Medicine, The University of British Columbia, Vancouver, British Columbia, Canada (C.C.N.); Department of Ophthalmology and The New Zealand National Eye Centre, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand (C.R.G.); and Physiologisches Institut, Justus-Liebig-Universität Giessen, Giessen, Germany (R.S.)
| | - Christian C Naus
- Physiology Group, Department of Basic Medical Sciences, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium (L.L.); Translational Research Program, Fred Hutchinson Cancer Research Center, Seattle, Washington (P.D.L.); Institute for Pharmacology, University of Leipzig, Leipzig, Germany (S.D.); Department of Pathology and Immunology, Department of Medical Specialization-Cardiology, University of Geneva, Geneva, Switzerland (B.R.K.); Department of Pharmacology and Pharmacotherapy, Semmelweis University, Budapest, Hungary (P.F.); Pharmahungary Group, Szeged, Hungary (P.F.); Department of Pediatrics, University of Chicago, Chicago, Illinois (E.C.B.); Department of Anatomy and Cell Biology, University of Western Ontario, Dental Science Building, London, Ontario, Canada (D.W.L.); Cellular and Physiological Sciences, Faculty of Medicine, The University of British Columbia, Vancouver, British Columbia, Canada (C.C.N.); Department of Ophthalmology and The New Zealand National Eye Centre, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand (C.R.G.); and Physiologisches Institut, Justus-Liebig-Universität Giessen, Giessen, Germany (R.S.)
| | - Colin R Green
- Physiology Group, Department of Basic Medical Sciences, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium (L.L.); Translational Research Program, Fred Hutchinson Cancer Research Center, Seattle, Washington (P.D.L.); Institute for Pharmacology, University of Leipzig, Leipzig, Germany (S.D.); Department of Pathology and Immunology, Department of Medical Specialization-Cardiology, University of Geneva, Geneva, Switzerland (B.R.K.); Department of Pharmacology and Pharmacotherapy, Semmelweis University, Budapest, Hungary (P.F.); Pharmahungary Group, Szeged, Hungary (P.F.); Department of Pediatrics, University of Chicago, Chicago, Illinois (E.C.B.); Department of Anatomy and Cell Biology, University of Western Ontario, Dental Science Building, London, Ontario, Canada (D.W.L.); Cellular and Physiological Sciences, Faculty of Medicine, The University of British Columbia, Vancouver, British Columbia, Canada (C.C.N.); Department of Ophthalmology and The New Zealand National Eye Centre, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand (C.R.G.); and Physiologisches Institut, Justus-Liebig-Universität Giessen, Giessen, Germany (R.S.)
| | - Rainer Schulz
- Physiology Group, Department of Basic Medical Sciences, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium (L.L.); Translational Research Program, Fred Hutchinson Cancer Research Center, Seattle, Washington (P.D.L.); Institute for Pharmacology, University of Leipzig, Leipzig, Germany (S.D.); Department of Pathology and Immunology, Department of Medical Specialization-Cardiology, University of Geneva, Geneva, Switzerland (B.R.K.); Department of Pharmacology and Pharmacotherapy, Semmelweis University, Budapest, Hungary (P.F.); Pharmahungary Group, Szeged, Hungary (P.F.); Department of Pediatrics, University of Chicago, Chicago, Illinois (E.C.B.); Department of Anatomy and Cell Biology, University of Western Ontario, Dental Science Building, London, Ontario, Canada (D.W.L.); Cellular and Physiological Sciences, Faculty of Medicine, The University of British Columbia, Vancouver, British Columbia, Canada (C.C.N.); Department of Ophthalmology and The New Zealand National Eye Centre, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand (C.R.G.); and Physiologisches Institut, Justus-Liebig-Universität Giessen, Giessen, Germany (R.S.)
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12
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Leithe E, Mesnil M, Aasen T. The connexin 43 C-terminus: A tail of many tales. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2017; 1860:48-64. [PMID: 28526583 DOI: 10.1016/j.bbamem.2017.05.008] [Citation(s) in RCA: 142] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2017] [Revised: 05/10/2017] [Accepted: 05/12/2017] [Indexed: 10/19/2022]
Abstract
Connexins are chordate gap junction channel proteins that, by enabling direct communication between the cytosols of adjacent cells, create a unique cell signalling network. Gap junctional intercellular communication (GJIC) has important roles in controlling cell growth and differentiation and in tissue development and homeostasis. Moreover, several non-canonical connexin functions unrelated to GJIC have been discovered. Of the 21 members of the human connexin family, connexin 43 (Cx43) is the most widely expressed and studied. The long cytosolic C-terminus (CT) of Cx43 is subject to extensive post-translational modifications that modulate its intracellular trafficking and gap junction channel gating. Moreover, the Cx43 CT contains multiple domains involved in protein interactions that permit crosstalk between Cx43 and cytoskeletal and regulatory proteins. These domains endow Cx43 with the capacity to affect cell growth and differentiation independently of GJIC. Here, we review the current understanding of the regulation and unique functions of the Cx43 CT, both as an essential component of full-length Cx43 and as an independent signalling hub. We highlight the complex regulatory and signalling networks controlled by the Cx43 CT, including the extensive protein interactome that underlies both gap junction channel-dependent and -independent functions. We discuss these data in relation to the recent discovery of the direct translation of specific truncated forms of Cx43. This article is part of a Special Issue entitled: Gap Junction Proteins edited by Jean Claude Herve.
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Affiliation(s)
- Edward Leithe
- Department of Molecular Oncology, Institute for Cancer Research, University of Oslo, NO-0424 Oslo, Norway; Centre for Cancer Biomedicine, Faculty of Medicine, University of Oslo, NO-0424 Oslo, Norway
| | - Marc Mesnil
- STIM Laboratory ERL 7368 CNRS - Faculté des Sciences Fondamentales et Appliquées, Université de Poitiers, Poitiers 86073, France
| | - Trond Aasen
- Translational Molecular Pathology, Vall d'Hebron Institute of Research (VHIR), Autonomous University of Barcelona, CIBERONC, 08035 Barcelona, Spain.
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13
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Totland MZ, Bergsland CH, Fykerud TA, Knudsen LM, Rasmussen NL, Eide PW, Yohannes Z, Sørensen V, Brech A, Lothe RA, Leithe E. E3 ubiquitin ligase NEDD4 induces endocytosis and lysosomal sorting of connexin43 to promote loss of gap junctions. J Cell Sci 2017; 130:2867-2882. [DOI: 10.1242/jcs.202408] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2017] [Accepted: 07/12/2017] [Indexed: 01/07/2023] Open
Abstract
Intercellular communication via gap junctions has an important role in controlling cell growth and in maintaining tissue homeostasis. Connexin43 is the most abundantly expressed gap junction channel protein in humans and acts as a tumor suppressor in multiple tissue types. Connexin43 is often dysregulated at the post-translational level during cancer development, resulting in loss of gap junctions. However, the molecular basis underlying the aberrant regulation of connexin43 in cancer cells has remained elusive. Here, we demonstrate that the oncogenic E3 ubiquitin ligase NEDD4 regulates the connexin43 protein level in HeLa cells, both under basal conditions and in response to protein kinase C activation. Furthermore, overexpression of NEDD4, but not a catalytically inactive form of NEDD4, was found to result in nearly complete loss of gap junctions and increased lysosomal degradation of connexin43 in both HeLa and C33A cervical carcinoma cells. Collectively, the data provide new insights into the molecular basis underlying the regulation of gap junction size and represent the first evidence that an oncogenic E3 ubiquitin ligase promotes loss of gap junctions and connexin43 degradation in human carcinoma cells.
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Affiliation(s)
- Max Z. Totland
- Department of Molecular Oncology, Institute for Cancer Research, Oslo University Hospital, Oslo, Norway
- Centre for Cancer Biomedicine, Faculty of Medicine, University of Oslo, Oslo, Norway
- Institute for Biosciences, University of Oslo, Oslo, Norway
- K.G. Jebsen Colorectal Cancer Research Centre, Oslo University Hospital, Oslo, Norway
| | - Christian H. Bergsland
- Department of Molecular Oncology, Institute for Cancer Research, Oslo University Hospital, Oslo, Norway
- Centre for Cancer Biomedicine, Faculty of Medicine, University of Oslo, Oslo, Norway
- Institute for Biosciences, University of Oslo, Oslo, Norway
- K.G. Jebsen Colorectal Cancer Research Centre, Oslo University Hospital, Oslo, Norway
| | - Tone A. Fykerud
- Department of Molecular Oncology, Institute for Cancer Research, Oslo University Hospital, Oslo, Norway
- Centre for Cancer Biomedicine, Faculty of Medicine, University of Oslo, Oslo, Norway
- K.G. Jebsen Colorectal Cancer Research Centre, Oslo University Hospital, Oslo, Norway
| | - Lars M. Knudsen
- Department of Molecular Oncology, Institute for Cancer Research, Oslo University Hospital, Oslo, Norway
- Centre for Cancer Biomedicine, Faculty of Medicine, University of Oslo, Oslo, Norway
- Institute for Biosciences, University of Oslo, Oslo, Norway
- K.G. Jebsen Colorectal Cancer Research Centre, Oslo University Hospital, Oslo, Norway
| | - Nikoline L. Rasmussen
- Department of Molecular Oncology, Institute for Cancer Research, Oslo University Hospital, Oslo, Norway
- Centre for Cancer Biomedicine, Faculty of Medicine, University of Oslo, Oslo, Norway
- Institute for Biosciences, University of Oslo, Oslo, Norway
- K.G. Jebsen Colorectal Cancer Research Centre, Oslo University Hospital, Oslo, Norway
| | - Peter W. Eide
- Department of Molecular Oncology, Institute for Cancer Research, Oslo University Hospital, Oslo, Norway
- Centre for Cancer Biomedicine, Faculty of Medicine, University of Oslo, Oslo, Norway
- K.G. Jebsen Colorectal Cancer Research Centre, Oslo University Hospital, Oslo, Norway
| | - Zeremariam Yohannes
- Department of Molecular Oncology, Institute for Cancer Research, Oslo University Hospital, Oslo, Norway
- Centre for Cancer Biomedicine, Faculty of Medicine, University of Oslo, Oslo, Norway
- K.G. Jebsen Colorectal Cancer Research Centre, Oslo University Hospital, Oslo, Norway
| | - Vigdis Sørensen
- Centre for Cancer Biomedicine, Faculty of Medicine, University of Oslo, Oslo, Norway
- Department of Molecular Cell Biology, Institute for Cancer Research, Oslo University Hospital, Oslo, Norway
- Department of Core Facilities, Institute for Cancer Research, Oslo University Hospital, Oslo, Norway
| | - Andreas Brech
- Centre for Cancer Biomedicine, Faculty of Medicine, University of Oslo, Oslo, Norway
- Institute for Biosciences, University of Oslo, Oslo, Norway
- Department of Molecular Cell Biology, Institute for Cancer Research, Oslo University Hospital, Oslo, Norway
- Department of Core Facilities, Institute for Cancer Research, Oslo University Hospital, Oslo, Norway
| | - Ragnhild A. Lothe
- Department of Molecular Oncology, Institute for Cancer Research, Oslo University Hospital, Oslo, Norway
- Centre for Cancer Biomedicine, Faculty of Medicine, University of Oslo, Oslo, Norway
- Institute for Biosciences, University of Oslo, Oslo, Norway
- K.G. Jebsen Colorectal Cancer Research Centre, Oslo University Hospital, Oslo, Norway
| | - Edward Leithe
- Department of Molecular Oncology, Institute for Cancer Research, Oslo University Hospital, Oslo, Norway
- Centre for Cancer Biomedicine, Faculty of Medicine, University of Oslo, Oslo, Norway
- K.G. Jebsen Colorectal Cancer Research Centre, Oslo University Hospital, Oslo, Norway
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14
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Falk MM, Bell CL, Kells Andrews RM, Murray SA. Molecular mechanisms regulating formation, trafficking and processing of annular gap junctions. BMC Cell Biol 2016; 17 Suppl 1:22. [PMID: 27230503 PMCID: PMC4896261 DOI: 10.1186/s12860-016-0087-7] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Internalization of gap junction plaques results in the formation of annular gap junction vesicles. The factors that regulate the coordinated internalization of the gap junction plaques to form annular gap junction vesicles, and the subsequent events involved in annular gap junction processing have only relatively recently been investigated in detail. However it is becoming clear that while annular gap junction vesicles have been demonstrated to be degraded by autophagosomal and endo-lysosomal pathways, they undergo a number of additional processing events. Here, we characterize the morphology of the annular gap junction vesicle and review the current knowledge of the processes involved in their formation, fission, fusion, and degradation. In addition, we address the possibility for connexin protein recycling back to the plasma membrane to contribute to gap junction formation and intercellular communication. Information on gap junction plaque removal from the plasma membrane and the subsequent processing of annular gap junction vesicles is critical to our understanding of cell-cell communication as it relates to events regulating development, cell homeostasis, unstable proliferation of cancer cells, wound healing, changes in the ischemic heart, and many other physiological and pathological cellular phenomena.
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Affiliation(s)
- Matthias M Falk
- Department of Biological Sciences, Lehigh University, Bethlehem, PA, 18049, USA.
| | - Cheryl L Bell
- Department of Cell Biology and Physiology, University of Pittsburgh, School of Medicine, Pittsburgh, PA, l5261, USA
| | | | - Sandra A Murray
- Department of Cell Biology and Physiology, University of Pittsburgh, School of Medicine, Pittsburgh, PA, l5261, USA.
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15
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Leithe E. Regulation of connexins by the ubiquitin system: Implications for intercellular communication and cancer. Biochim Biophys Acta Rev Cancer 2016; 1865:133-46. [DOI: 10.1016/j.bbcan.2016.02.001] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2015] [Revised: 01/15/2016] [Accepted: 02/04/2016] [Indexed: 12/31/2022]
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16
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Bell CL, Murray SA. Adrenocortical Gap Junctions and Their Functions. Front Endocrinol (Lausanne) 2016; 7:82. [PMID: 27445985 PMCID: PMC4925680 DOI: 10.3389/fendo.2016.00082] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/04/2016] [Accepted: 06/20/2016] [Indexed: 12/21/2022] Open
Abstract
Adrenal cortical steroidogenesis and proliferation are thought to be modulated by gap junction-mediated direct cell-cell communication of regulatory molecules between cells. Such communication is regulated by the number of gap junction channels between contacting cells, the rate at which information flows between these channels, and the rate of channel turnover. Knowledge of the factors regulating gap junction-mediated communication and the turnover process are critical to an understanding of adrenal cortical cell functions, including development, hormonal response to adrenocorticotropin, and neoplastic dedifferentiation. Here, we review what is known about gap junctions in the adrenal gland, with particular attention to their role in adrenocortical cell steroidogenesis and proliferation. Information and insight gained from electrophysiological, molecular biological, and imaging (immunocytochemical, freeze fracture, transmission electron microscopic, and live cell) techniques will be provided.
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Affiliation(s)
- Cheryl L. Bell
- Department of Cell Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Sandra A. Murray
- Department of Cell Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
- *Correspondence: Sandra A. Murray,
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17
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Kinase programs spatiotemporally regulate gap junction assembly and disassembly: Effects on wound repair. Semin Cell Dev Biol 2015; 50:40-8. [PMID: 26706150 DOI: 10.1016/j.semcdb.2015.12.010] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2015] [Accepted: 12/08/2015] [Indexed: 01/05/2023]
Abstract
Gap junctions are highly ordered plasma membrane domains that are constantly assembled, remodeled and turned over due to the short half-life of connexins, the integral membrane proteins that form gap junctions. Connexin 43 (Cx43), by far the most widely expressed connexin, is phosphorylated at multiple serine residues in the cytoplasmic, C-terminal region allowing for exquisite cellular control over gap junctional communication. This is evident during epidermal wounding where spatiotemporal changes in connexin expression occur as cells are instructed whether to die, proliferate or migrate to promote repair. Early gap junctional communication is required for initiation of keratinocyte migration, but accelerated Cx43 turnover is also critical for proper wound healing at later stages. These events are controlled via a "kinase program" where sequential phosphorylation of Cx43 leads to reductions in Cx43's half-life and significant depletion of gap junctions from the plasma membrane within several hours. The complex regulation of gap junction assembly and turnover affords several steps where intervention might speed wound healing.
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18
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Narayanan KB, Ali M, Barclay BJ, Cheng QS, D'Abronzo L, Dornetshuber-Fleiss R, Ghosh PM, Gonzalez Guzman MJ, Lee TJ, Leung PS, Li L, Luanpitpong S, Ratovitski E, Rojanasakul Y, Romano MF, Romano S, Sinha RK, Yedjou C, Al-Mulla F, Al-Temaimi R, Amedei A, Brown DG, Ryan EP, Colacci A, Hamid RA, Mondello C, Raju J, Salem HK, Woodrick J, Scovassi AI, Singh N, Vaccari M, Roy R, Forte S, Memeo L, Kim SY, Bisson WH, Lowe L, Park HH. Disruptive environmental chemicals and cellular mechanisms that confer resistance to cell death. Carcinogenesis 2015; 36 Suppl 1:S89-110. [PMID: 26106145 DOI: 10.1093/carcin/bgv032] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Cell death is a process of dying within biological cells that are ceasing to function. This process is essential in regulating organism development, tissue homeostasis, and to eliminate cells in the body that are irreparably damaged. In general, dysfunction in normal cellular death is tightly linked to cancer progression. Specifically, the up-regulation of pro-survival factors, including oncogenic factors and antiapoptotic signaling pathways, and the down-regulation of pro-apoptotic factors, including tumor suppressive factors, confers resistance to cell death in tumor cells, which supports the emergence of a fully immortalized cellular phenotype. This review considers the potential relevance of ubiquitous environmental chemical exposures that have been shown to disrupt key pathways and mechanisms associated with this sort of dysfunction. Specifically, bisphenol A, chlorothalonil, dibutyl phthalate, dichlorvos, lindane, linuron, methoxychlor and oxyfluorfen are discussed as prototypical chemical disruptors; as their effects relate to resistance to cell death, as constituents within environmental mixtures and as potential contributors to environmental carcinogenesis.
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Affiliation(s)
- Kannan Badri Narayanan
- Department of Chemistry and Biochemistry, Yeungnam University, Gyeongsan 712-749, South Korea, Sultan Zainal Abidin University, Malaysia, Plant Biotechnologies Inc, St. Albert AB, Canada, Computer Science Department, Southern Illinois University, Carbondale, IL 62901, USA, Department of Urology, University of California Davis, Sacramento, CA 95817, USA, Department of Pharmacology and Toxicology, University of Vienna, Austria, University of Puerto Rico, Medical Sciences Campus, School of Public Health, Nutrition Program, San Juan Puerto Rico 00936-5067, USA, Department of Anatomy, College of Medicine, Yeungnam University, Daegu, 705-717, South Korea, School of Biomedical Science, The Chinese University Of Hong Kong, Hong Kong, China, Siriraj Center of Excellence for Stem Cell Research, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand, Department of Otolaryngology/Head and Neck Surgery, Head and Neck Cancer Research Division, Johns Hopkins University School of Medicine, Baltimore, MD 21231, USA, Department of Pharmaceutical Sciences, Mary Babb Randolph Cancer Center, West Virginia University, Morgantown, WV 26506, USA, Department of Molecular Medicine and Medical Biotechnology, Federico II University of Naples, 80131 Naples, Italy, Department of Molecular and Experimental Medicine, MEM 180, The Scripps Research Institute, La Jolla, CA 92037, USA, Department of Biology, Jackson State University, Jackson, MS 39217, USA, Department of Pathology, Kuwait University, Safat 13110, Kuwait, Department of Experimental and Clinical Medicine, University of Firenze, Firenze, 50134, Italy, Department of Environmental and Radiological Health Sciences, Colorado state University/ Colorado School of Public Health, Fort Collins, CO 80523-1680, USA, Center for Environmental Carcinogenesis and Risk Assessment, Environmental Protection and Health Prevention Agency, Bologna, 40126, Italy, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, Se
| | - Manaf Ali
- Sultan Zainal Abidin University, Malaysia
| | | | - Qiang Shawn Cheng
- Computer Science Department, Southern Illinois University, Carbondale, IL 62901, USA
| | - Leandro D'Abronzo
- Department of Urology, University of California Davis, Sacramento, CA 95817, USA
| | | | - Paramita M Ghosh
- Department of Urology, University of California Davis, Sacramento, CA 95817, USA
| | - Michael J Gonzalez Guzman
- University of Puerto Rico, Medical Sciences Campus, School of Public Health, Nutrition Program, San Juan Puerto Rico 00936-5067, USA
| | - Tae-Jin Lee
- Department of Anatomy, College of Medicine, Yeungnam University, Daegu, 705-717, South Korea
| | - Po Sing Leung
- School of Biomedical Science, The Chinese University Of Hong Kong, Hong Kong, China
| | - Lin Li
- School of Biomedical Science, The Chinese University Of Hong Kong, Hong Kong, China
| | - Suidjit Luanpitpong
- Siriraj Center of Excellence for Stem Cell Research, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand
| | - Edward Ratovitski
- Department of Otolaryngology/Head and Neck Surgery, Head and Neck Cancer Research Division, Johns Hopkins University School of Medicine, Baltimore, MD 21231, USA
| | - Yon Rojanasakul
- Department of Pharmaceutical Sciences, Mary Babb Randolph Cancer Center, West Virginia University, Morgantown, WV 26506, USA
| | - Maria Fiammetta Romano
- Department of Molecular Medicine and Medical Biotechnology, Federico II University of Naples, 80131 Naples, Italy
| | - Simona Romano
- Department of Molecular Medicine and Medical Biotechnology, Federico II University of Naples, 80131 Naples, Italy
| | - Ranjeet K Sinha
- Department of Molecular and Experimental Medicine, MEM 180, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Clement Yedjou
- Department of Biology, Jackson State University, Jackson, MS 39217, USA
| | - Fahd Al-Mulla
- Department of Pathology, Kuwait University, Safat 13110, Kuwait
| | | | - Amedeo Amedei
- Department of Experimental and Clinical Medicine, University of Firenze, Firenze, 50134, Italy
| | - Dustin G Brown
- Department of Environmental and Radiological Health Sciences, Colorado state University/ Colorado School of Public Health, Fort Collins, CO 80523-1680, USA
| | - Elizabeth P Ryan
- Department of Environmental and Radiological Health Sciences, Colorado state University/ Colorado School of Public Health, Fort Collins, CO 80523-1680, USA
| | - Annamaria Colacci
- Center for Environmental Carcinogenesis and Risk Assessment, Environmental Protection and Health Prevention Agency, Bologna, 40126, Italy
| | - Roslida A Hamid
- Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, Serdang, Selangor 43400, Malaysia
| | - Chiara Mondello
- Institute of Molecular Genetics, National Research Council, Pavia, 27100, Italy
| | - Jayadev Raju
- Toxicology Research Division, Bureau of Chemical Safety Food Directorate, Health Products and Food Branch Health Canada, Ottawa, Ontario, K1A0K9, Canada
| | - Hosni K Salem
- Urology Department, Kasr Al-Ainy School of Medicine, Cairo University, El Manial, Cairo, 12515, Egypt
| | - Jordan Woodrick
- Molecular Oncology Program, Lombardi Comprehensive Cancer Center, Georgetown University Medical Center, Washington DC, 20057, USA
| | - A Ivana Scovassi
- Institute of Molecular Genetics, National Research Council, Pavia, 27100, Italy
| | - Neetu Singh
- Advenced Molecular Science Research Centre, King George's Medical University, Lucknow, Uttar Pradesh, 226003, India
| | - Monica Vaccari
- Center for Environmental Carcinogenesis and Risk Assessment, Environmental Protection and Health Prevention Agency, Bologna, 40126, Italy
| | - Rabindra Roy
- Molecular Oncology Program, Lombardi Comprehensive Cancer Center, Georgetown University Medical Center, Washington DC, 20057, USA
| | - Stefano Forte
- Mediterranean Institute of Oncology, Viagrande, 95029, Italy
| | - Lorenzo Memeo
- Mediterranean Institute of Oncology, Viagrande, 95029, Italy
| | - Seo Yun Kim
- Department of Internal Medicine, Korea Cancer Center Hospital, Seoul 139-706, South Korea
| | - William H Bisson
- Environmental and Molecular Toxicology, Environmental Health Science Center, Oregon State University, Corvallis, OR 97331, USA and
| | - Leroy Lowe
- Getting to Know Cancer, Truro, Nova Scotia, Canada
| | - Hyun Ho Park
- Department of Chemistry and Biochemistry, Yeungnam University, Gyeongsan 712-749, South Korea, Sultan Zainal Abidin University, Malaysia, Plant Biotechnologies Inc, St. Albert AB, Canada, Computer Science Department, Southern Illinois University, Carbondale, IL 62901, USA, Department of Urology, University of California Davis, Sacramento, CA 95817, USA, Department of Pharmacology and Toxicology, University of Vienna, Austria, University of Puerto Rico, Medical Sciences Campus, School of Public Health, Nutrition Program, San Juan Puerto Rico 00936-5067, USA, Department of Anatomy, College of Medicine, Yeungnam University, Daegu, 705-717, South Korea, School of Biomedical Science, The Chinese University Of Hong Kong, Hong Kong, China, Siriraj Center of Excellence for Stem Cell Research, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand, Department of Otolaryngology/Head and Neck Surgery, Head and Neck Cancer Research Division, Johns Hopkins University School of Medicine, Baltimore, MD 21231, USA, Department of Pharmaceutical Sciences, Mary Babb Randolph Cancer Center, West Virginia University, Morgantown, WV 26506, USA, Department of Molecular Medicine and Medical Biotechnology, Federico II University of Naples, 80131 Naples, Italy, Department of Molecular and Experimental Medicine, MEM 180, The Scripps Research Institute, La Jolla, CA 92037, USA, Department of Biology, Jackson State University, Jackson, MS 39217, USA, Department of Pathology, Kuwait University, Safat 13110, Kuwait, Department of Experimental and Clinical Medicine, University of Firenze, Firenze, 50134, Italy, Department of Environmental and Radiological Health Sciences, Colorado state University/ Colorado School of Public Health, Fort Collins, CO 80523-1680, USA, Center for Environmental Carcinogenesis and Risk Assessment, Environmental Protection and Health Prevention Agency, Bologna, 40126, Italy, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, Se
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19
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Nahta R, Al-Mulla F, Al-Temaimi R, Amedei A, Andrade-Vieira R, Bay SN, Brown DG, Calaf GM, Castellino RC, Cohen-Solal KA, Colacci A, Cruickshanks N, Dent P, Di Fiore R, Forte S, Goldberg GS, Hamid RA, Krishnan H, Laird DW, Lasfar A, Marignani PA, Memeo L, Mondello C, Naus CC, Ponce-Cusi R, Raju J, Roy D, Roy R, Ryan EP, Salem HK, Scovassi AI, Singh N, Vaccari M, Vento R, Vondráček J, Wade M, Woodrick J, Bisson WH. Mechanisms of environmental chemicals that enable the cancer hallmark of evasion of growth suppression. Carcinogenesis 2015; 36 Suppl 1:S2-18. [PMID: 26106139 DOI: 10.1093/carcin/bgv028] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
As part of the Halifax Project, this review brings attention to the potential effects of environmental chemicals on important molecular and cellular regulators of the cancer hallmark of evading growth suppression. Specifically, we review the mechanisms by which cancer cells escape the growth-inhibitory signals of p53, retinoblastoma protein, transforming growth factor-beta, gap junctions and contact inhibition. We discuss the effects of selected environmental chemicals on these mechanisms of growth inhibition and cross-reference the effects of these chemicals in other classical cancer hallmarks.
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Affiliation(s)
- Rita Nahta
- Departments of Pharmacology and Hematology & Medical Oncology, Emory University School of Medicine and Winship Cancer Institute, Atlanta, GA 30322, USA, Department of Pathology, Kuwait University, Safat 13110, Kuwait, Department of Experimental and Clinical Medicine, University of Firenze, 50134 Florence, Italy, Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada, Program in Genetics and Molecular Biology, Graduate Division of Biological and Biomedical Sciences, Emory University, Atlanta, GA 30322, USA, Department of Environmental and Radiological Health Sciences/Colorado State University/Colorado School of Public Health, Fort Collins, CO 80523-1680, USA, Center for Radiological Research, Columbia University Medical Center, New York, NY 10032, USA, Instituto de Alta Investigacion, Universidad de Tarapaca, Arica 8097877, Chile, Division of Hematology and Oncology, Department of Pediatrics, Children's Healthcare of Atlanta and Emory University, Atlanta, GA 30322, USA, Department of Medicine/Medical Oncology, Rutgers Cancer Institute of New Jersey, New Brunswick, NJ 08901-1914, USA, Center for Environmental Carcinogenesis and Risk Assessment, Environmental Protection and Health Prevention Agency, Bologna 40126, Italy, Departments of Neurosurgery and Biochemistry and Massey Cancer Center, Virginia Commonwealth University, Richmond, VA 980033, USA, Department of Biological, Chemical, and Pharmaceutical Sciences and Technologies, Polyclinic Plexus, University of Palermo, 90127 Palermo, Italy, Mediterranean Institute of Oncology, 95029 Viagrande, Italy, Graduate School of Biomedical Sciences and Department of Molecular Biology, School of Osteopathic Medicine, Rowan University, Stratford, NJ 08084-1501, USA, Department of Biomedical Science, Faculty of Medicine and Health Sciences, University Putra, Serdang, Selangor 43400, Malaysia, Department of Anatomy and Cell Biology, University of Western Ontario, London, Ontari
| | - Fahd Al-Mulla
- Department of Pathology, Kuwait University, Safat 13110, Kuwait
| | | | - Amedeo Amedei
- Department of Experimental and Clinical Medicine, University of Firenze, 50134 Florence, Italy
| | - Rafaela Andrade-Vieira
- Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada
| | - Sarah N Bay
- Program in Genetics and Molecular Biology, Graduate Division of Biological and Biomedical Sciences, Emory University, Atlanta, GA 30322, USA
| | - Dustin G Brown
- Department of Environmental and Radiological Health Sciences/Colorado State University/Colorado School of Public Health, Fort Collins, CO 80523-1680, USA
| | - Gloria M Calaf
- Center for Radiological Research, Columbia University Medical Center, New York, NY 10032, USA, Instituto de Alta Investigacion, Universidad de Tarapaca, Arica 8097877, Chile
| | - Robert C Castellino
- Division of Hematology and Oncology, Department of Pediatrics, Children's Healthcare of Atlanta and Emory University, Atlanta, GA 30322, USA
| | - Karine A Cohen-Solal
- Department of Medicine/Medical Oncology, Rutgers Cancer Institute of New Jersey, New Brunswick, NJ 08901-1914, USA
| | - Annamaria Colacci
- Center for Environmental Carcinogenesis and Risk Assessment, Environmental Protection and Health Prevention Agency, Bologna 40126, Italy
| | - Nichola Cruickshanks
- Departments of Neurosurgery and Biochemistry and Massey Cancer Center, Virginia Commonwealth University, Richmond, VA 980033, USA
| | - Paul Dent
- Departments of Neurosurgery and Biochemistry and Massey Cancer Center, Virginia Commonwealth University, Richmond, VA 980033, USA
| | - Riccardo Di Fiore
- Department of Biological, Chemical, and Pharmaceutical Sciences and Technologies, Polyclinic Plexus, University of Palermo, 90127 Palermo, Italy
| | - Stefano Forte
- Mediterranean Institute of Oncology, 95029 Viagrande, Italy
| | - Gary S Goldberg
- Graduate School of Biomedical Sciences and Department of Molecular Biology, School of Osteopathic Medicine, Rowan University, Stratford, NJ 08084-1501, USA
| | - Roslida A Hamid
- Department of Biomedical Science, Faculty of Medicine and Health Sciences, University Putra, Serdang, Selangor 43400, Malaysia
| | - Harini Krishnan
- Graduate School of Biomedical Sciences and Department of Molecular Biology, School of Osteopathic Medicine, Rowan University, Stratford, NJ 08084-1501, USA
| | - Dale W Laird
- Department of Anatomy and Cell Biology, University of Western Ontario, London, Ontario N6A 5C1, Canada
| | - Ahmed Lasfar
- Department of Pharmacology and Toxicology, Ernest Mario School of Pharmacy, Rutgers, the State University of New Jersey, Piscataway, NJ 60503, USA
| | - Paola A Marignani
- Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada
| | - Lorenzo Memeo
- Mediterranean Institute of Oncology, 95029 Viagrande, Italy
| | - Chiara Mondello
- Institute of Molecular Genetics, National Research Council, 27100 Pavia, Italy
| | - Christian C Naus
- Department of Cellular & Physiological Sciences, Life Sciences Institute, Faculty of Medicine, The University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada
| | - Richard Ponce-Cusi
- Instituto de Alta Investigacion, Universidad de Tarapaca, Arica 8097877, Chile
| | - Jayadev Raju
- Toxicology Research Division, Bureau of Chemical Safety Food Directorate, Health Products and Food Branch Health Canada, Ottawa, Ontario K1A0K9, Canada
| | - Debasish Roy
- Department of Natural Science, The City University of New York at Hostos Campus, Bronx, NY 10451, USA
| | - Rabindra Roy
- Molecular Oncology Program, Lombardi Comprehensive Cancer Center, Georgetown University Medical Center, Washington DC 20057, USA
| | - Elizabeth P Ryan
- Department of Environmental and Radiological Health Sciences/Colorado State University/Colorado School of Public Health, Fort Collins, CO 80523-1680, USA
| | - Hosni K Salem
- Urology Dept., kasr Al-Ainy School of Medicine, Cairo University, El Manial, Cairo 12515, Egypt
| | - A Ivana Scovassi
- Institute of Molecular Genetics, National Research Council, 27100 Pavia, Italy
| | - Neetu Singh
- Advanced Molecular Science Research Centre, King George's Medical University, Lucknow, UP 226003, India
| | - Monica Vaccari
- Center for Environmental Carcinogenesis and Risk Assessment, Environmental Protection and Health Prevention Agency, Bologna 40126, Italy
| | - Renza Vento
- Department of Biological, Chemical, and Pharmaceutical Sciences and Technologies, Polyclinic Plexus, University of Palermo, 90127 Palermo, Italy, Sbarro Institute for Cancer Research and Molecular Medicine, College of Science and Technology, Temple University, Philadelphia, PA 19122, USA
| | - Jan Vondráček
- Department of Cytokinetics, Institute of Biophysics AS CR, Brno 612 65, Czech Republic
| | - Mark Wade
- Center for Genomic Science of IIT@SEMM, Istituto Italiano di Tecnologia (IIT), Milan 16163, Italy and
| | - Jordan Woodrick
- Molecular Oncology Program, Lombardi Comprehensive Cancer Center, Georgetown University Medical Center, Washington DC 20057, USA
| | - William H Bisson
- Environmental and Molecular Toxicology, Environmental Health Sciences Center, Oregon State University, Corvallis, OR 97331, USA
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20
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Sovadinova I, Babica P, Böke H, Kumar E, Wilke A, Park JS, Trosko JE, Upham BL. Phosphatidylcholine Specific PLC-Induced Dysregulation of Gap Junctions, a Robust Cellular Response to Environmental Toxicants, and Prevention by Resveratrol in a Rat Liver Cell Model. PLoS One 2015; 10:e0124454. [PMID: 26023933 PMCID: PMC4449167 DOI: 10.1371/journal.pone.0124454] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2014] [Accepted: 03/10/2015] [Indexed: 12/04/2022] Open
Abstract
Dysregulation of gap junctional intercellular communication (GJIC) has been associated with different pathologies, including cancer; however, molecular mechanisms regulating GJIC are not fully understood. Mitogen Activated Protein Kinase (MAPK)-dependent mechanisms of GJIC-dysregulation have been well-established, however recent discoveries have implicated phosphatidylcholine-specific phospholipase C (PC-PLC) in the regulation of GJIC. What is not known is how prevalent these two signaling mechanisms are in toxicant/toxin-induced dysregulation of GJIC, and do toxicants/toxins work through either signaling mechanisms or both, or through alternative signaling mechanisms. Different chemical toxicants were used to assess whether they dysregulate GJIC via MEK or PC-PLC, or both Mek and PC-PLC, or through other signaling pathways, using a pluripotent rat liver epithelial oval-cell line, WB-F344. Epidermal growth factor, 12-O-tetradecanoylphorbol-13-acetate, thrombin receptor activating peptide-6 and lindane regulated GJIC through a MEK1/2-dependent mechanism that was independent of PC-PLC; whereas PAHs, DDT, PCB 153, dicumylperoxide and perfluorodecanoic acid inhibited GJIC through PC-PLC independent of Mek. Dysregulation of GJIC by perfluorooctanoic acid and R59022 required both MEK1/2 and PC-PLC; while benzoylperoxide, arachidonic acid, 18β-glycyrrhetinic acid, perfluorooctane sulfonic acid, 1-monolaurin, pentachlorophenol and alachlor required neither MEK1/2 nor PC-PLC. Resveratrol prevented dysregulation of GJIC by toxicants that acted either through MEK1/2 or PC-PLC. Except for alachlor, resveratrol did not prevent dysregulation of GJIC by toxicants that worked through PC-PLC-independent and MEK1/2-independent pathways, which indicated at least two other, yet unidentified, pathways that are involved in the regulation of GJIC. In conclusion: the dysregulation of GJIC is a contributing factor to the cancer process; however the underlying mechanisms by which gap junction channels are closed by toxicants vary. Thus, accurate assessments of risk posed by toxic agents, and the role of dietary phytochemicals play in preventing or reversing the effects of these agents must take into account the specific mechanisms involved in the cancer process.
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Affiliation(s)
- Iva Sovadinova
- Department of Pediatrics & Human Development; Center for Integrative Toxicology; and the Food Safety & Toxicology Center, Michigan State University, East Lansing, Michigan, 48824, United States of America
- Research Centre for Toxic Compounds in the Environment—RECETOX, Masaryk University, Kamenice 5, CZ62500, Brno, Czech Republic
| | - Pavel Babica
- Department of Pediatrics & Human Development; Center for Integrative Toxicology; and the Food Safety & Toxicology Center, Michigan State University, East Lansing, Michigan, 48824, United States of America
- Department of Experimental Phycology and Ecotoxicology, Institute of Botany ASCR, Lidicka 25/27, CZ60200, Brno, Czech Republic
| | - Hatice Böke
- Department of Pediatrics & Human Development; Center for Integrative Toxicology; and the Food Safety & Toxicology Center, Michigan State University, East Lansing, Michigan, 48824, United States of America
| | - Esha Kumar
- Department of Pediatrics & Human Development; Center for Integrative Toxicology; and the Food Safety & Toxicology Center, Michigan State University, East Lansing, Michigan, 48824, United States of America
| | - Andrew Wilke
- Department of Pediatrics & Human Development; Center for Integrative Toxicology; and the Food Safety & Toxicology Center, Michigan State University, East Lansing, Michigan, 48824, United States of America
| | - Joon-Suk Park
- Department of Pediatrics & Human Development; Center for Integrative Toxicology; and the Food Safety & Toxicology Center, Michigan State University, East Lansing, Michigan, 48824, United States of America
- Laboratory Animal Center, Daegu-Gyeongbuk Medical Innovation Foundation, Daegu, Korea
| | - James E. Trosko
- Department of Pediatrics & Human Development; Center for Integrative Toxicology; and the Food Safety & Toxicology Center, Michigan State University, East Lansing, Michigan, 48824, United States of America
| | - Brad L. Upham
- Department of Pediatrics & Human Development; Center for Integrative Toxicology; and the Food Safety & Toxicology Center, Michigan State University, East Lansing, Michigan, 48824, United States of America
- * E-mail:
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21
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De Mello WC. Chemical Communication between Heart Cells is Disrupted by Intracellular Renin and Angiotensin II: Implications for Heart Development and Disease. Front Endocrinol (Lausanne) 2015; 6:72. [PMID: 26042086 PMCID: PMC4437035 DOI: 10.3389/fendo.2015.00072] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/07/2015] [Accepted: 04/22/2015] [Indexed: 12/11/2022] Open
Abstract
HighlightsIntracellular renin and angiotensin disrupts chemical communication in heart.Epigenetic modification of renin angiotensin aldosterone system (RAAS) and heart disease.Intracrine renin angiotensin and metabolic cooperation.Gap junction, intracellular renin and angiotensin, cellular patterns, and heart development. The finding that intracellular renin and angiotensin II (Ang II) disrupts chemical communication and impairs metabolic cooperation between cardiomyocytes induced by aldosterone, hyperglycemia, and pathological conditions like myocardial ischemia is discussed. The hypothesis is presented that epigenetic changes of the renin angiotensin aldosterone system (RAAS) are responsible for cardiovascular abnormalities, including the expression of RAAS components inside cardiac myocytes (intracrine RAAS) with serious consequences including inhibition of electrical and chemical communication in the heart, resulting in metabolic disarrangement and cardiac arrhythmias. Moreover, the inhibition of gap junctional communication induced by intracellular Ang II or renin can contribute to the selection of cellular patterns during heart development.
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Affiliation(s)
- Walmor C. De Mello
- School of Medicine, University of Puerto Rico, San Juan, PR, USA
- *Correspondence: Walmor C. De Mello, School of Medicine, UPR, Medical Sciences Campus, San Juan, PR 00936, USA,
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22
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Xie F, Yi SL, Hao L, Zhang Y, Zhong JQ. Role of group I metabotropic glutamate receptors, mGluR1/mGluR5, in connexin43 phosphorylation and inhibition of gap junctional intercellular communication in H9c2 cardiomyoblast cells. Mol Cell Biochem 2014; 400:213-22. [DOI: 10.1007/s11010-014-2278-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2014] [Accepted: 11/15/2014] [Indexed: 12/11/2022]
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23
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Axelsen LN, Calloe K, Holstein-Rathlou NH, Nielsen MS. Managing the complexity of communication: regulation of gap junctions by post-translational modification. Front Pharmacol 2013; 4:130. [PMID: 24155720 PMCID: PMC3804956 DOI: 10.3389/fphar.2013.00130] [Citation(s) in RCA: 98] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2013] [Accepted: 09/30/2013] [Indexed: 12/21/2022] Open
Abstract
Gap junctions are comprised of connexins that form cell-to-cell channels which couple neighboring cells to accommodate the exchange of information. The need for communication does, however, change over time and therefore must be tightly controlled. Although the regulation of connexin protein expression by transcription and translation is of great importance, the trafficking, channel activity and degradation are also under tight control. The function of connexins can be regulated by several post translational modifications, which affect numerous parameters; including number of channels, open probability, single channel conductance or selectivity. The most extensively investigated post translational modifications are phosphorylations, which have been documented in all mammalian connexins. Besides phosphorylations, some connexins are known to be ubiquitinated, SUMOylated, nitrosylated, hydroxylated, acetylated, methylated, and γ-carboxyglutamated. The aim of the present review is to summarize our current knowledge of post translational regulation of the connexin family of proteins.
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Affiliation(s)
- Lene N Axelsen
- Department of Biomedical Sciences and The Danish National Research Foundation Centre for Cardiac Arrhythmia, Faculty of Health and Medical Sciences, University of Copenhagen Copenhagen, Denmark
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24
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Cell motility in models of wounded human skin is improved by Gap27 despite raised glucose, insulin and IGFBP-5. Exp Cell Res 2012; 319:390-401. [PMID: 23262023 DOI: 10.1016/j.yexcr.2012.12.013] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2012] [Revised: 12/12/2012] [Accepted: 12/13/2012] [Indexed: 11/21/2022]
Abstract
Reducing Cx43 expression stimulates skin wound healing. This is mimicked in models when Cx43 function is blocked by the connexin mimetic peptide Gap27. IGF-I also stimulates wound healing with IGFBP-5 attenuating its actions. Further, the IGF-I to IGFBP-5 ratio is altered in diabetic skin, where wound closure is impaired. We investigated whether Gap27 remains effective in augmenting scrape-wound closure in human skin wound models simulating diabetes-induced changes, using culture conditions with raised glucose, insulin and IGFBP-5. Gap27 increased scrape-wound closure in normal glucose and insulin (NGI) and to a lesser extent in high glucose and insulin (HGI). IGF-I enhanced scrape-wound closure in keratinocytes whereas IGFBP-5 inhibited this response. Gap27 overcame the inhibitory effects of IGFBP-5 on IGF-I activity. Connexin-mediated communication (CMC) was reduced in HGI, despite raised Cx43, and Gap27 significantly decreased CMC in NGI and HGI. IGF-I and IGFBP-5 did not affect CMC. IGF-I increased keratinocyte proliferation in NGI, and Gap27 increased proliferation in NGI to a greater extent than in HGI. We conclude that IGF-I and Gap27 stimulate scrape-wound closure by independent mechanisms with Gap27 inhibiting Cx43 function. Gap27 can enhance wound closure in diabetic conditions, irrespective of the IGF-I:IGFBP-5 balance.
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25
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Chen VC, Kristensen AR, Foster LJ, Naus CC. Association of Connexin43 with E3 Ubiquitin Ligase TRIM21 Reveals a Mechanism for Gap Junction Phosphodegron Control. J Proteome Res 2012; 11:6134-46. [DOI: 10.1021/pr300790h] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Affiliation(s)
- Vincent C. Chen
- Department
of Biochemistry and Molecular Biology, Centre for High-Throughput
Biology, ‡Department
of Cellular and Physiological Sciences, Life Sciences
Institute, University of British Columbia, 2350 Health Sciences Mall, Vancouver, British Columbia, V6T 1Z3,
Canada
| | - Anders R. Kristensen
- Department
of Biochemistry and Molecular Biology, Centre for High-Throughput
Biology, ‡Department
of Cellular and Physiological Sciences, Life Sciences
Institute, University of British Columbia, 2350 Health Sciences Mall, Vancouver, British Columbia, V6T 1Z3,
Canada
| | - Leonard J. Foster
- Department
of Biochemistry and Molecular Biology, Centre for High-Throughput
Biology, ‡Department
of Cellular and Physiological Sciences, Life Sciences
Institute, University of British Columbia, 2350 Health Sciences Mall, Vancouver, British Columbia, V6T 1Z3,
Canada
| | - Christian C. Naus
- Department
of Biochemistry and Molecular Biology, Centre for High-Throughput
Biology, ‡Department
of Cellular and Physiological Sciences, Life Sciences
Institute, University of British Columbia, 2350 Health Sciences Mall, Vancouver, British Columbia, V6T 1Z3,
Canada
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26
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Fykerud TA, Kjenseth A, Schink KO, Sirnes S, Bruun J, Omori Y, Brech A, Rivedal E, Leithe E. Smad ubiquitination regulatory factor-2 controls gap junction intercellular communication by modulating endocytosis and degradation of connexin43. J Cell Sci 2012; 125:3966-76. [DOI: 10.1242/jcs.093500] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Gap junctions consist of arrays of intercellular channels that enable adjacent cells to communicate both electrically and metabolically. Gap junction channels are made of a family of integral membrane proteins called connexins, of which the best-studied member is connexin43. Gap junctions are dynamic plasma membrane domains, and connexin43 has a high turnover rate in most tissue types. However, the mechanisms involved in the regulation of connexin43 endocytosis and transport to lysosomes are still poorly understood. Here, we demonstrate by live-cell imaging analysis that treatment of cells with 12-O-tetradecanoylphorbol 13-acetate (TPA) induces endocytosis of subdomains of connexin43 gap junctions. The internalized, connexin43-enriched vesicles were found to fuse with early endosomes, which was followed by transport of connexin43 to the lumen of early endosomes. The HECT E3 ubiquitin ligase smad ubiquitination regulatory factor-2 (Smurf2) was found to be recruited to connexin43 gap junctions in response to TPA treatment. Depletion of Smurf2 by small interfering RNA (siRNA) resulted in enhanced levels of connexin43 gap junctions between adjacent cells and increased gap junction intercellular communication. Smurf2 depletion also counteracted the TPA-induced endocytosis and degradation of connexin43. Collectively, these data identify Smurf2 as a novel regulator of connexin43 gap junctions.
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27
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Dunn CA, Su V, Lau AF, Lampe PD. Activation of Akt, not connexin 43 protein ubiquitination, regulates gap junction stability. J Biol Chem 2011; 287:2600-7. [PMID: 22139843 DOI: 10.1074/jbc.m111.276261] [Citation(s) in RCA: 87] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The pore-forming gap junctional protein connexin 43 (Cx43) has a short (1-3 h) half-life in cells in tissue culture and in whole tissues. Although critical for cellular function in all tissues, the process of gap junction turnover is not well understood because treatment of cells with a proteasomal inhibitor results in larger gap junctions but little change in total Cx43 protein whereas lysosomal inhibitors increase total, mostly nonjunctional Cx43. To better understand turnover and identify potential sites of Cx43 ubiquitination, we prepared constructs of Cx43 with different lysines converted to arginines. However, when transfected into cells, a mutant version of Cx43 with all lysines converted to arginines behaved similarly to wild type in the presence of proteasomal and lysosomal inhibitors, indicating that ubiquitination of Cx43 did not appear to be playing a role in gap junction stability. Through the use of inhibitors and dominant negative constructs, we found that Akt (protein kinase B) activity controlled gap junction stability and was necessary to form larger stable gap junctions. Akt activation was increased upon proteasomal inhibition and resulted in phosphorylation of Cx43 at Akt phosphorylation consensus sites. Thus, we conclude that Cx43 ubiquitination is not necessary for the regulation of Cx43 turnover; rather, Akt activity, probably through direct phosphorylation of Cx43, controls gap junction stability. This linkage of a kinase involved in controlling cell survival and growth to gap junction stability may mechanistically explain how gap junctions and Akt play similar regulatory roles.
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Affiliation(s)
- Clarence A Dunn
- Molecular Diagnostics Program, Human Biology and Public Health Sciences, Fred Hutchinson Cancer Research Center, Seattle, Washington 98109, USA
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Wang CY, Liu HJ, Chen HJ, Lin YC, Wang HH, Hung TC, Yeh HI. AGE-BSA down-regulates endothelial connexin43 gap junctions. BMC Cell Biol 2011; 12:19. [PMID: 21575204 PMCID: PMC3224147 DOI: 10.1186/1471-2121-12-19] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2010] [Accepted: 05/16/2011] [Indexed: 12/26/2022] Open
Abstract
Background Advanced glycation end products generated in the circulation of diabetic patients were reported to affect the function of vascular wall. We examined the effects of advanced glycation end products-bovine serum albumin (AGE-BSA) on endothelial connexin43 (Cx43) expression and gap-junction communication. Results In human aortic endothelial cells (HAEC) treated with a series concentrations of AGE-BSA (0-500 μg/ml) for 24 and 48 hours, Cx43 transcript and Cx43 protein were reduced in a dose dependent manner. In addition, gap-junction communication was reduced. To clarify the mechanisms underlying the down-regulation, MAPKs pathways in HAEC were examined. Both a MEK1 inhibitor (PD98059) and a p38 MAPK inhibitor (SB203580) significantly reversed the reductions of Cx43 mRNA and protein induced by AGE-BSA. Consistently, phosphorylation of ERK and p38 MAPK was enhanced in response to exposure to AGE-BSA. However, all reversions of down-regulated Cx43 by inhibitors did not restore the functional gap-junction communication. Conclusions AGE-BSA down-regulated Cx43 expression in HAEC, mainly through reduced Cx43 transcription, and the process involved activation of ERK and p38 MAPK.
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Affiliation(s)
- Chi-Young Wang
- Department of Internal Medicine, Mackay Memorial Hospital, New Taipei City 251, Taiwan
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Peptidoglycan derived from Staphylococcus epidermidis induces Connexin43 hemichannel activity with consequences on the innate immune response in endothelial cells. Biochem J 2010; 432:133-43. [PMID: 20815816 DOI: 10.1042/bj20091753] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Gram-positive bacterial cell wall components including PGN (peptidoglycan) elicit a potent pro-inflammatory response in diverse cell types, including endothelial cells, by activating TLR2 (Toll-like receptor 2) signalling. The functional integrity of the endothelium is under the influence of a network of gap junction intercellular communication channels composed of Cxs (connexins) that also form hemichannels, signalling conduits that are implicated in ATP release and purinergic signalling. PGN modulates Cx expression in a variety of cell types, yet effects in endothelial cells remain unresolved. Using the endothelial cell line b.End5, a 6 h challenge with PGN induced IL-6 (interleukin 6), TLR2 and Cx43 mRNA expression that was associated with enhanced Cx43 protein expression and gap junction coupling. Cx43 hemichannel activity, measured by ATP release from the cells, was induced following 15 min of exposure to PGN. Inhibition of hemichannel activity with carbenoxolone or apyrase prevented induction of IL-6 and TLR2 mRNA expression by PGN, but had no effect on Cx43 mRNA expression levels. In contrast, knockdown of TLR2 expression had no effect on PGN-induced hemichannel activity, but reduced the level of TLR2 and Cx43 mRNA expression following 6 h of PGN challenge. PGN also acutely induced hemichannel activity in HeLa cells transfected to express Cx43, but had no effect in Cx43-deficient HeLa OHIO cells. All ATP responses were blocked with Cx-specific channel blockers. We conclude that acute Cx43 hemichannel signalling plays a role in the initiation of early innate immune responses in the endothelium.
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Meacci E, Bini F, Sassoli C, Martinesi M, Squecco R, Chellini F, Zecchi-Orlandini S, Francini F, Formigli L. Functional interaction between TRPC1 channel and connexin-43 protein: a novel pathway underlying S1P action on skeletal myogenesis. Cell Mol Life Sci 2010; 67:4269-85. [PMID: 20614160 PMCID: PMC11115629 DOI: 10.1007/s00018-010-0442-3] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2010] [Revised: 06/07/2010] [Accepted: 06/21/2010] [Indexed: 10/19/2022]
Abstract
We recently demonstrated that skeletal muscle differentiation induced by sphingosine 1-phosphate (S1P) requires gap junctions and transient receptor potential canonical 1 (TRPC1) channels. Here, we searched for the signaling pathway linking the channel activity with Cx43 expression/function, investigating the involvement of the Ca(2+)-sensitive protease, m-calpain, and its targets in S1P-induced C2C12 myoblast differentiation. Gene silencing and pharmacological inhibition of TRPC1 significantly reduced Cx43 up-regulation and Cx43/cytoskeletal interaction elicited by S1P. TRPC1-dependent functions were also required for the transient increase of m-calpain activity/expression and the subsequent decrease of PKCα levels. Remarkably, Cx43 expression in S1P-treated myoblasts was reduced by m-calpain-siRNA and enhanced by pharmacological inhibition of classical PKCs, stressing the relevance for calpain/PKCα axis in Cx43 protein remodeling. The contribution of this pathway in myogenesis was also investigated. In conclusion, these findings provide novel mechanisms by which S1P regulates myoblast differentiation and offer interesting therapeutic options to improve skeletal muscle regeneration.
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Affiliation(s)
- Elisabetta Meacci
- Department of Biochemical Sciences, University of Florence, Viale GB Morgagni 50, 50134, Florence, Italy.
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Green tea prevents down-regulation of gap junction intercellular communication in human keratinocytes treated with PMA. Eur Arch Otorhinolaryngol 2010; 268:885-92. [DOI: 10.1007/s00405-010-1411-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2010] [Accepted: 10/13/2010] [Indexed: 10/18/2022]
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Johnstone SR, Best AK, Wright CS, Isakson BE, Errington RJ, Martin PE. Enhanced connexin 43 expression delays intra-mitotic duration and cell cycle traverse independently of gap junction channel function. J Cell Biochem 2010; 110:772-82. [PMID: 20512937 DOI: 10.1002/jcb.22590] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Connexins (Cxs) and gap junction (GJ)-mediated communication have been linked with the regulation of cell cycle traverse. However, it is not clear whether Cx expression or GJ channel function are the key mediators in this process or at what stage this regulation may occur. We therefore tested the hypothesis that enhanced Cx expression could alter the rate of cell cycle traverse independently of GJ channel function. Sodium butyrate (NaBu) or anti-arrhythmic peptide (AAP10) were used to enhance Cx expression in HeLa cells stably expressing Cx43 (HeLa-43) and primary cultures of human fibroblasts (HFF) that predominantly express Cx43. To reduce GJ-mediated communication, 18-alpha-glycyrrhetinic acid (GA) was used. In HeLa-43 and HFF cells, NaBu and AAP10 enhanced Cx43 expression and increased channel function, while GA reduced GJ-mediated communication but did not significantly alter Cx43 expression levels. Timelapse microscopy and flow cytometry of HeLa-WT (wild-type, Cx deficient) and HeLa-43 cells dissected cell cycle traverse and enabled measurements of intra-mitotic time and determined levels of G1 arrest. Enhanced Cx43 expression increased mitotic durations corresponding with a G1 delay in cell cycle, which was linked to an increase in expression of the cell cycle inhibitor p21(waf1/cip1) in both HeLa-43 and HFF cells. Reductions in Cx43 channel function did not abrogate these responses, indicating that GJ channel function was not a critical factor in reducing cell proliferation in either cell type. We conclude that enhanced Cx43 expression and not GJ-mediated communication, is involved in regulating cell cycle traverse.
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Affiliation(s)
- Scott R Johnstone
- Department of Biological and Biomedical Sciences, School of Life Sciences, Glasgow Caledonian University, 70 Cowcaddens Rd, Glasgow, Scotland G4 0BA, UK
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Zhu H, Wang H, Zhang X, Hou X, Cao K, Zou J. Arrhythmogenic properties of dismantling cadherin-mediated adhesion in murine hearts. J Biomed Res 2010; 24:292-300. [PMID: 23554643 PMCID: PMC3596595 DOI: 10.1016/s1674-8301(10)60041-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2010] [Indexed: 11/28/2022] Open
Abstract
Objective To evaluate the arrhythmogenic effects of dismantling cadherin-mediated adhesion by recombinant mouse aminopeptidase N (rmAPN) in murine hearts. Methods rmAPN was incubated with cultured neonatal rat cardiomyocytes as well as being infused in adult mice. The cell-cell connections were immunolabelled and observed by laser confocal microscopy. Disruption of the N-terminal of N-cadherin (N-cad) was detected by western blot and quantitative immunofluorescence. The risk of inducible ventricular tachyarrhythmia was evaluated in mice by an electrophysiological study. Results Disrupted cell-cell contact was observed in cultured neonatal rat cardiomyocytes in response to 30-40 ng/µL rmAPN. Loss of the N-terminal in N-cad and altered distribution of connexin 43 (Cx43) were observed in hearts from rmAPN-infused mice. In addition, a reduction of phosphorylated Cx43 was also detected concomitant with redistribution of Cx43. Electrophysiological studies of rmAPN-infused mice showed prolonged QRS duration and increased inducibility of ventricular tachycardias. Conclusion Disruption of N-cad by rmAPN contributes to gap junction remodeling and may elicit arrhythmogenic effects. The disorder of adherent junctions by proteolytic enzymes may play an important role in arrhythmogenic mechanisms in correlated diseases.
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Affiliation(s)
- Hongjun Zhu
- Department of Cardiology, the First Affiliated Hospital of Nanjing Medical University, Nanjing 210029, Jiangsu Province, China
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Leithe E, Kjenseth A, Bruun J, Sirnes S, Rivedal E. Inhibition of connexin 43 gap junction channels by the endocrine disruptor ioxynil. Toxicol Appl Pharmacol 2010; 247:10-7. [PMID: 20510257 DOI: 10.1016/j.taap.2010.05.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2010] [Revised: 05/04/2010] [Accepted: 05/11/2010] [Indexed: 10/19/2022]
Abstract
Gap junctions are intercellular plasma membrane domains containing channels that mediate transport of ions, metabolites and small signaling molecules between adjacent cells. Gap junctions play important roles in a variety of cellular processes, including regulation of cell growth and differentiation, maintenance of tissue homeostasis and embryogenesis. The constituents of gap junction channels are a family of trans-membrane proteins called connexins, of which the best-studied is connexin 43. Connexin 43 functions as a tumor suppressor protein in various tissue types and is frequently dysregulated in human cancers. The pesticide ioxynil has previously been shown to act as an endocrine disrupting chemical and has multiple effects on the thyroid axis. Furthermore, both ioxynil and its derivative ioxynil octanoate have been reported to induce tumors in animal bioassays. However, the molecular mechanisms underlying the possible tumorigenic effects of these compounds are unknown. In the present study we show that ioxynil and ioxynil octanoate are strong inhibitors of connexin 43 gap junction channels. Both compounds induced rapid loss of connexin 43 gap junctions at the plasma membrane and increased connexin 43 degradation. Ioxynil octanoate, but not ioxynil, was found to be a strong activator of ERK1/2. The compounds also had different effects on the phosphorylation status of connexin 43. Taken together, the data show that ioxynil and ioxynil octanoate are potent inhibitors of intercellular communication via gap junctions.
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Affiliation(s)
- Edward Leithe
- Department of Cancer Prevention, Institute for Cancer Research, Norwegian Radium Hospital, Oslo University Hospital and Centre for Cancer Biomedicine, University of Oslo, Oslo, Norway
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Hsiao HJ, Liu PA, Yeh HI, Wang CY. Classical swine fever virus down-regulates endothelial connexin 43 gap junctions. Arch Virol 2010; 155:1107-16. [PMID: 20473696 DOI: 10.1007/s00705-010-0693-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2009] [Accepted: 02/26/2010] [Indexed: 10/19/2022]
Abstract
Classical swine fever is a contagious disease of pigs characterized by fatal hemorrhagic fever. Classical swine fever virus (CSFV) induces the expression of pro-inflammatory and pro-coagulant factors of vascular endothelial cells and establishes a long-term infection. This study aimed to understand the effect of CSFV on endothelial connexin 43 (Cx43) expression and gap junctional intercellular coupling (GJIC). Porcine aortic endothelial cells were infected with CSFV at different multiplicity of infection for 48 h. Semi-quantitative RT-PCR, immunoconfocal microscopy, and Western blotting showed that the transcription and translation of Cx43 were reduced, and this was associated with an attenuation of GJIC. This decrease occurred in a time-dependent manner. An ERK inhibitor (PD98059), a JNK inhibitor (SP600125), and proteasome/lysosome inhibitors all significantly reversed the reduction in Cx43 protein levels without any influence on the titer of progeny virus. In addition, CSFV activated ERK and JNK in a time-dependent manner and down-regulated Cx43 promoter activity, mainly through decreased AP2 binding. This effect was primarily caused by the replication of CSFV rather than a consequence of cytokines being induced by CSFV infection of endothelial cells.
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Affiliation(s)
- Hsiang-Jung Hsiao
- Department of Veterinary Medicine, National Chung Hsing University, Taichung 402, Taiwan
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36
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Rivedal E, Witz G, Leithe E. Gap junction intercellular communication and benzene toxicity. Chem Biol Interact 2010; 184:229-32. [DOI: 10.1016/j.cbi.2009.11.013] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2009] [Revised: 10/21/2009] [Accepted: 11/16/2009] [Indexed: 11/28/2022]
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Deng F, Olesen P, Foldbjerg R, Dang DA, Guo X, Autrup H. Silver nanoparticles up-regulate Connexin43 expression and increase gap junctional intercellular communication in human lung adenocarcinoma cell line A549. Nanotoxicology 2010; 4:186-95. [DOI: 10.3109/17435390903576451] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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38
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Liu Y, Zhang X, Li ZJ, Chen XH. Up-regulation of Cx43 expression and GJIC function in acute leukemia bone marrow stromal cells post-chemotherapy. Leuk Res 2009; 34:631-40. [PMID: 19910046 DOI: 10.1016/j.leukres.2009.10.013] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2009] [Revised: 09/10/2009] [Accepted: 10/14/2009] [Indexed: 10/20/2022]
Abstract
Gap junction intercellular communication (GJIC) among bone marrow stromal cells (BMSCs) most frequently occurs through a channel composed of connexin43 (Cx43). Dysregulation of connexin expression is believed to have a role in carcinogenesis. In earlier work, we found that in acute leukemia BMSCs, expression of Cx43 and functioning GJIC declined. However, there has been no evaluation of whether GJIC in BMSCs in complete remission (CR) post-chemotherapy is different from GJIC pre-chemotherapy. We studied Cx43 expression and tested GJIC function in human bone marrow cultures under different physiological and pathological conditions. To assay Cx43 expression we used immunocytochemistry, laser scan confocal microscopy (LSCM), flow cytometry and RT-PCR. The results showed that the expression level of Cx43 and its mRNA in acute leukemia BMSCs post-chemotherapy was significantly higher and similar to normal levels than in primary acute leukemia BMSCs (p<0.01). Functional tests in cultures using dye transfer and fluorescence recovery after photobleaching (FRAP) assays showed that the function of GJIC in acute leukemia BMSCs was significantly improved following effective chemotherapy. Our findings suggest Cx43 and GJIC might be involved in the courses of occurrence, development and termination of acute leukemia, and effective chemotherapy could improve Cx43 expression and GJIC function that were dysfunctional prior to treatment.
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Affiliation(s)
- Yao Liu
- Department of Hematology, Xinqiao Hospital, The Third Military Medical University, Shapingba District, Xinqiao Street, Chongqing 400037, China
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Gilleron J, Carette D, Carpentier F, Segretain D, Pointis G. Three-dimensional analysis of connexin43 gap junction in the ex vivo rat seminiferous tubules: Short-term effects of hormonal effectors. Microsc Res Tech 2009; 72:845-55. [DOI: 10.1002/jemt.20731] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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40
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Vinken M, Doktorova T, Decrock E, Leybaert L, Vanhaecke T, Rogiers V. Gap junctional intercellular communication as a target for liver toxicity and carcinogenicity. Crit Rev Biochem Mol Biol 2009; 44:201-22. [PMID: 19635038 DOI: 10.1080/10409230903061215] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Direct communication between hepatocytes, mediated by gap junctions, constitutes a major regulatory platform in the control of liver homeostasis, ranging from hepatocellular proliferation to hepatocyte cell death. Inherent to this pivotal task, gap junction functionality is frequently disrupted upon impairment of the homeostatic balance, as occurs during liver toxicity and carcinogenicity. In the present paper, the deleterious effects of a number of chemical and biological toxic compounds on hepatic gap junctions are discussed, including environmental pollutants, biological toxins, organic solvents, pesticides, pharmaceuticals, peroxides, metals and phthalates. Particular attention is paid to the molecular mechanisms that underlie the abrogation of gap junction functionality. Since hepatic gap junctions are specifically targeted by tumor promoters and epigenetic carcinogens, both in vivo and in vitro, inhibition of gap junction functionality is considered as a suitable indicator for the detection of nongenotoxic hepatocarcinogenicity.
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Affiliation(s)
- Mathieu Vinken
- Department of Toxicology, Faculty of Medicine and Pharmacy, Vrije Universiteit Brussel, Brussels, Belgium.
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41
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Heyman NS, Kurjiaka DT, Ek Vitorin JF, Burt JM. Regulation of gap junctional charge selectivity in cells coexpressing connexin 40 and connexin 43. Am J Physiol Heart Circ Physiol 2009; 297:H450-9. [PMID: 19465552 PMCID: PMC2711728 DOI: 10.1152/ajpheart.00287.2009] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/24/2009] [Accepted: 05/20/2009] [Indexed: 11/22/2022]
Abstract
Expression of connexin 40 (Cx40) and Cx43 in cardiovascular tissues varies as a function of age, injury, and development with unknown consequences on the selectivity of junctional communication and its acute regulation. We investigated the PKC-dependent regulation of charge selectivity in junctions composed of Cx43, Cx40, or both by simultaneous assessment of junctional permeance rate constants (B(dye)) for dyes of similar size but opposite charge, N,N,N-trimethyl-2-[methyl-(7-nitro-2,1,3-benzoxadiol-4-yl)amino]ethanaminium (NBD-M-TMA; +1) and Alexa 350 (-1). The ratio of dye rate constants (B(NBD-M-TMA)/B(Alexa 350)) indicated that Cx40 junctions are cation selective (10.7 +/- 0.5), whereas Cx43 junction are nonselective (1.22 +/- 0.14). In coexpressing cells, a broad range of junctional selectivities was observed with mean cation selectivity increasing as the Cx40 to Cx43 expression ratio increased. PKC activation reduced or eliminated dye permeability of Cx43 junctions without altering their charge selectivity, had no effect on either permeability or charge selectivity of Cx40 junctions, and significantly increased the cation selectivity of junctions formed by coexpressing cells (approaching charge selectivity of Cx40 junctions). Junctions composed of Cx43 truncated at residue 257 (Cx43tr) were also not charge selective, but when Cx43tr was coexpressed with Cx40, a broad range of junctional selectivities that was unaffected by PKC activation was observed. Thus, whereas the charge selectivities of homomeric/homotypic Cx43 and Cx40 junctions appear invariant, the selectivities of junctions formed by cells coexpressing Cx40 and Cx43 vary considerably, reflecting both their relative expression levels and phosphorylation-dependent regulation. Such regulation could represent a mechanism by which coexpressing cells such as vascular endothelium and atrial cells regulate acutely the selective intercellular communication mediated by their gap junctions.
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Easton JA, Petersen JS, Martin PEM. The anti-arrhythmic peptide AAP10 remodels Cx43 and Cx40 expression and function. NAUNYN-SCHMIEDEBERG'S ARCHIVES OF PHARMACOLOGY 2009; 380:11-24. [PMID: 19326099 DOI: 10.1007/s00210-009-0411-2] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2008] [Accepted: 03/04/2009] [Indexed: 10/21/2022]
Abstract
The anti-arrhythmic peptide AAP10 has previously been shown to acutely upregulate electrical cell-to-cell coupling mediated via connexin 43 gap junctions. In the present work, we have further examined the connexin (Cx) specificity and mechanism of action of this peptide in HeLa cells expressing Cx43, Cx40 or Cx26. The ability of cells to transfer the small fluorescent dyes Alexa 488 (MW 570) or Alexa 594 (MW 759), as markers for metabolic coupling mediated via gap junctions, before and after exposure to AAP10 and/or the protein kinase C inhibitor chelerythrine for 5 h was determined by microinjection analysis. Immunofluorescence analysis assessed the effect of AAP10 on the spatial localisation of each Cx sub-type. Cell extracts were isolated for Western blot and reverse transcription polymerase chain reaction analysis at 0, 5, 10, 18 and 24 h following exposure to AAP10 and the relative Cx expression profiles determined. AAP10 enhanced the ability of Cx43 and, to a lesser extent, Cx40 to transfer Alexa 488. It also enhanced the ability of Cx43 to transfer Alexa 594 but not Cx40. Inhibition of protein kinase C blocked this enhanced response in both Cx sub-types. Western blot analysis determined that AAP10 induced Cx40 protein expression over periods of up to 24 h with an associated increase in the localisation of Cx40 at points of cell-to-cell contact following 24-h exposure. Cx43 expression was transiently induced following exposure to the peptide for 5-10 h, with an associated increase in Cx43 at points of cell-to-cell contact, returning to control levels by 18-24 h, via a post-translational mechanism independent of chelerythrine. A transient increase in Cx40 mRNA expression but not Cx43 mRNA expression was also observed. By contrast, AAP10 had no effect on the ability of Cx26 gap junctions to transfer the dyes or on the level of Cx26 expression. We propose that AAP10 is a versatile peptide that remodels metabolic coupling via Cx43 and to a lesser extent Cx40 gap junction channels via an initial protein-kinase-C-dependent pathway modifying local responses at the plasma membrane. This is followed by enhanced Cx43 or Cx40 protein expression.
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Affiliation(s)
- Jennifer A Easton
- Department of Biomedical and Biological Sciences, School of Life Sciences, Glasgow Caledonian University, Glasgow G4OBA, Scotland, UK
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43
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Hanstein R, Trotter J, Behl C, Clement AB. Increased connexin 43 expression as a potential mediator of the neuroprotective activity of the corticotropin-releasing hormone. Mol Endocrinol 2009; 23:1479-93. [PMID: 19460861 DOI: 10.1210/me.2009-0022] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
CRH is a major central stress mediator, but also a potent neuroprotective effector. The mechanisms by which CRH mediates its neuroprotective actions are largely unknown. Here, we describe that the gap junction molecule connexin43 (Cx43) mediates neuroprotective effects of CRH toward experimentally induced oxidative stress. An enhanced gap junction communication has been reported to contribute to neuroprotection after neurotoxic insults. We show that CRH treatment up-regulates Cx43 expression and gap junctional communication in a CRH receptor-dependent manner in IMR32 neuroblastoma cells, primary astrocytes, and organotypic hippocampal slice cultures. MAPKs and protein kinase A-cAMP response element binding protein -coupled pathways are involved in the signaling cascade from CRH to enhanced Cx43 function. Inhibition of CRH-promoted gap junction communication by the gap junction inhibitor carbenoxolone could prevent neuroprotective actions of CRH in cell and tissue culture models suggesting that gap junction molecules are involved in the neuroprotective effects of CRH. The extent of oxidative stress-induced protein carbonylation and cell death inversely correlated with Cx43 protein levels as shown by Cx43 small interfering RNA knockdown experiments. Coculture studies of primary neurons and astrocytes revealed that astrocytic Cx43 likely contributes to the neuroprotective effects of CRH. To our knowledge this is the first description of Cx43 as a potential mediator of the neuroprotective actions of CRH.
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Affiliation(s)
- Regina Hanstein
- Institute of Pathobiochemistry, University Medical Center, Johannes Gutenberg-University, 55099 Mainz, Germany
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44
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Hattis D, Chu M, Rahmioglu N, Goble R, Verma P, Hartman K, Kozlak M. A preliminary operational classification system for nonmutagenic modes of action for carcinogenesis. Crit Rev Toxicol 2009; 39:97-138. [PMID: 19009457 DOI: 10.1080/10408440802307467] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
This article proposes a system of categories for nonmutagenic modes of action for carcinogenesis. The classification is of modes of action rather than individual carcinogens, because the same compound can affect carcinogenesis in more than one way. Basically, we categorize modes of action as: (1) co-initiation (facilitating the original mutagenic changes in stem and progenitor cells that start the cancer process) (e.g. induction of activating enzymes for other carcinogens); (2) promotion (enhancing the relative growth vs differentiation/death of initiated clones (e.g. inhibition of growth-suppressing cell-cell communication); (3) progression (enhancing the growth, malignancy, or spread of already developed tumors) (e.g. suppression of immune surveillance, hormonally mediated growth stimulation for tumors with appropriate receptors by estrogens); and (4) multiphase (e.g., "epigenetic" silencing of tumor suppressor genes). A priori, agents that act at relatively early stages in the process are expected to manifest greater relative susceptibility in early life, whereas agents that act via later stage modes will tend to show greater susceptibility for exposures later in life.
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Affiliation(s)
- D Hattis
- George Perkins Marsh Institute, Clark University, Worcester, Massachusetts, USA
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Interplay between PKC and the MAP kinase pathway in Connexin43 phosphorylation and inhibition of gap junction intercellular communication. Biochem Biophys Res Commun 2009; 382:41-5. [PMID: 19258009 DOI: 10.1016/j.bbrc.2009.02.141] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2009] [Accepted: 02/21/2009] [Indexed: 11/22/2022]
Abstract
Gap junction channels are made of a family proteins called connexins. The best-studied type of connexin, Connexin43 (Cx43), is phosphorylated at several sites in its C-terminus. The tumor-promoting phorbol ester TPA strongly inhibits Cx43 gap junction channels. In this study we have investigated mechanisms involved in TPA-induced phosphorylation of Cx43 and inhibition of gap junction channels. The data show that TPA-induced inhibition of gap junction intercellular communication (GJIC) is dependent on both PKC and the MAP kinase pathway. The data suggest that PKC-induced activation of MAP kinase partly involves Src-independent trans-activation of the EGF receptor, and that TPA-induced shift in SDS-PAGE gel mobility of Cx43 is caused by MAP kinase phosphorylation, whereas phosphorylation of S368 by PKC does not alter gel migration of Cx43. We also show that TPA, in addition to phosphorylation of S368, also induces phosphorylation of S255 and S262, in a MAP kinase-dependent manner. The data add to our understanding of the molecular mechanisms involved in the interplay between signaling pathways in regulation of GJIC.
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Šimečková P, Vondráček J, Andrysík Z, Zatloukalová J, Krčmář P, Kozubík A, Machala M. The 2,2′,4,4′,5,5′-Hexachlorobiphenyl–Enhanced Degradation of Connexin 43 Involves Both Proteasomal and Lysosomal Activities. Toxicol Sci 2008; 107:9-18. [DOI: 10.1093/toxsci/kfn202] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Velasquez Almonacid LA, Tafuri S, Dipineto L, Matteoli G, Fiorillo E, Della Morte R, Fioretti A, Menna LF, Staiano N. Role of connexin-43 hemichannels in the pathogenesis of Yersinia enterocolitica. Vet J 2008; 182:452-7. [PMID: 18824377 DOI: 10.1016/j.tvjl.2008.08.011] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2008] [Revised: 07/10/2008] [Accepted: 08/07/2008] [Indexed: 01/09/2023]
Abstract
Connexin (Cx) channels are sites of cytoplasmic communication between contacting cells. Evidence indicates that the opening of hemichannels occurs under both physiological and pathological conditions. In this paper, the involvement of Cx-43 hemichannels is demonstrated in the pathogenesis of Yersinia. Parental HeLa cells and transfected HeLa cells stably expressing Cx-43 (HCx43) were infected with Yersiniaenterocolitica, and bacterial uptake was measured by the colony-forming unit method. Bacterial uptake was higher in HCx43 cells than in parental cells and was inhibited by the Cx channel blocker, 18-alpha-glycyrrhetinic acid (AGA). The inhibitory effect of AGA was more pronounced on the Y. enterocolitica uptake by HCx43 cells than by parental cells. The ability of HCx43 cells to incorporate the permeable fluorescent tracer Lucifer Yellow (LY) was assessed. Dye incorporation was inhibited by AGA, whereas Y. enterocolitica infection of HCx43 cells increased LY incorporation. Western blotting analysis demonstrated that Y. enterocolitica infection of HCx43 cells induced tyrosine phosphorylation of Cx-43, thus supporting a critical role for Cx-43 in the strategies exploited by bacterial pathogens to invade non-phagocytic cells.
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Affiliation(s)
- L A Velasquez Almonacid
- Dipartimento di Patologia e Sanità Animale, Università di Napoli Federico II, via F. Delpino 1, 80137 Napoli, Italy
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Gotow T, Shiozaki M, Higashi T, Yoshimura K, Shibata M, Kominami E, Uchiyama Y. Hepatic gap junctions in the hepatocarcinogen-resistant DRH rat. Histochem Cell Biol 2008; 130:583-94. [PMID: 18633633 DOI: 10.1007/s00418-008-0473-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/29/2008] [Indexed: 12/29/2022]
Abstract
Although the gap junction or connexin (Cx) is considered to be a tumor-suppressor, it is also required for tumor promotion. Therefore, we examined hepatic gap junctions in hepatocarcinogen-resistant (DRH) rats. Specifically, we investigated gap junction structure and Cx32 expression during normal conditions and in response to a hepatocarcinogen, 3'-methyl-4-dimethylaminoazobenzene (3'-MeDAB). On a basal diet without 3'-MeDAB, hepatic gap junctions and Cx32 protein expression were greater in DRH rats than in control Donryu rats, as evidenced by morphometry, immunohistochemistry and immunoblotting. On a diet containing 3'-MeDAB, gap junctions and expressed Cx32 were increased significantly in Donryu rats, but not in DRH rats. In this condition, Donryu rats lost weight but DRH rats increased relative liver weight. After 3'-MeDAB treatment, cathepsin D expression in hepatocytes was significantly increased only in Donryu rats, indicating that DRH rats were less susceptible to 3'-MeDAB. The abundance of mitogen-activated protein kinase, some constituent of which might be associated with the degree of Cx protein phosphorylation, was reduced to a greater extent in Donryu than in DRH rats after 3'-MeDAB treatment. The resistance of DRH rats to carcinogenesis may be due partially to their stabilized gap junctions, which could coordinate metabolic coupling to evade 3'-MeDAB toxicity.
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Affiliation(s)
- Takahiro Gotow
- Laboratory of Cell Biology, College of Nutrition, Koshien University, 10-1 Momijigaoka, Takarazuka Hyogo 665-0006, Japan.
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Chaumontet C, Bex V, Véran F, Martel P. The vitamin E analog tocopherol succinate strongly inhibits gap junctional intercellular communication in rat liver epithelial cells (IAR203). J Nutr Biochem 2008; 19:263-8. [PMID: 17683923 DOI: 10.1016/j.jnutbio.2007.03.005] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2006] [Revised: 02/01/2007] [Accepted: 03/27/2007] [Indexed: 01/09/2023]
Abstract
Vitamin E is a scavenger molecule trapping free radicals in biological membranes. However, it has also been shown to elicit the formation of reactive oxygen species and apoptosis in cancer cells. In this study, we tested the ability of alpha-tocopherol, tocopherol acetate, tocopherol phosphate and tocopherol succinate (TS) to modulate gap junctional intercellular communication in the rat liver epithelial cell line IAR203, as measured by the transfer of Lucifer yellow. While alpha-tocopherol, tocopherol acetate and tocopherol phosphate moderately reduced the dye transfer, TS at 10 and 25 microM strongly inhibited it, probably via the induction of the hypophosphorylation of connexin 43. Our results show that, besides their interesting antioxidant properties, vitamin E analogs, especially TS, can exert adverse effects on gap junctional intercellular communication, which could explain their controversial effects in carcinogenesis.
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Affiliation(s)
- Catherine Chaumontet
- Laboratoire de Nutrition et Sécurité Alimentaire, INRA, Domaine de Vilvert, Jouy-en-Josas Cedex, France.
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Kim JH, Kang NJ, Lee BK, Lee KW, Lee HJ. Gallic acid, a metabolite of the antioxidant propyl gallate, inhibits gap junctional intercellular communication via phosphorylation of connexin 43 and extracellular-signal-regulated kinase1/2 in rat liver epithelial cells. Mutat Res 2008; 638:175-183. [PMID: 18054051 DOI: 10.1016/j.mrfmmm.2007.10.005] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2007] [Revised: 10/07/2007] [Accepted: 10/08/2007] [Indexed: 05/25/2023]
Abstract
Propyl gallate and its metabolite, gallic acid, are widely used as antioxidants in the food industry, but they have been shown to exhibit liver toxicity and enhance carcinogenesis. In the present study, we investigated the possible undesirable effects of propyl gallate and gallic acid on gap junctional intercellular communication (GJIC), inhibition of which is closely linked to carcinogenesis. Gallic acid and propyl gallate exhibited dose-dependent free-radical-scavenging activities as determined by 1,1-diphenyl-2-picrylhydrazyl- or 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid)-radical-scavenging assays, and the free-radical-scavenging activity of gallic acid was stronger than that of propyl gallate. However, using WB-F344 rat liver epithelial cells, gallic acid inhibited GJIC in a dose-dependent manner, while propyl gallate had no significant effect compared with untreated controls. The gallic-acid-induced inhibition of GJIC was reversible, with a recovery of nearly 65% after 120 min. Gallic acid induced the phosphorylation of connexin 43 (Cx43) and phosphorylation of extracellular-signal-regulated kinase1/2 (ERK1/2). The gallic-acid-induced inhibition of GJIC was attenuated by treatment with mitogen-activated protein kinase kinase inhibitors (U0126 and PD098059). U0126 blocked the gallic-acid-induced phosphorylation of Cx43 and ERK1/2, indicating that the gallic-acid-induced inhibition of GJIC is mediated by phosphorylation of Cx43 via activation of ERK1/2. In addition, gallic-acid-induced inhibition of GJIC was protected by ascorbic acid and quercetin, which might represent a simple example of the different effects of natural antioxidants in carcinogenesis.
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Affiliation(s)
- Jong Hun Kim
- Department of Agricultural Biotechnology and Center for Agricultural Biomaterials, Seoul National University, Seoul 151-921, Republic of Korea
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