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Matarrese P, Signore M, Ascione B, Fanelli G, Paggi MG, Abbruzzese C. Chlorpromazine overcomes temozolomide resistance in glioblastoma by inhibiting Cx43 and essential DNA repair pathways. J Transl Med 2024; 22:667. [PMID: 39026284 PMCID: PMC11256652 DOI: 10.1186/s12967-024-05501-3] [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: 05/06/2024] [Accepted: 07/10/2024] [Indexed: 07/20/2024] Open
Abstract
BACKGROUND In the fight against GBM, drug repurposing emerges as a viable and time-saving approach to explore new treatment options. Chlorpromazine, an old antipsychotic medication, has recently arisen as a promising candidate for repositioning in GBM therapy in addition to temozolomide, the first-line standard of care. We previously demonstrated the antitumor efficacy of chlorpromazine and its synergistic effects with temozolomide in suppressing GBM cell malignant features in vitro. This prompted us to accomplish a Phase II clinical trial to evaluate the efficacy and safety of adding chlorpromazine to temozolomide in GBM patients with unmethylated MGMT gene promoter. In this in vitro study, we investigate the potential role of chlorpromazine in overcoming temozolomide resistance. METHODS In our experimental set, we analyzed Connexin-43 expression at both the transcriptional and protein levels in control- and chlorpromazine-treated GBM cells. DNA damage and subsequent repair were assessed by immunofluorescence of γ-H2AX and Reverse-Phase Protein microArrays in chlorpromazine treated GBM cell lines. To elucidate the relationship between DNA repair systems and chemoresistance, we analyzed a signature of DNA repair genes in GBM cells after treatment with chlorpromazine, temozolomide and Connexin-43 downregulation. RESULTS Chlorpromazine treatment significantly downregulated connexin-43 expression in GBM cells, consequently compromising connexin-dependent cellular resilience, and ultimately contributing to cell death. In line with this, we observed concordant post-translational modifications of molecular determinants involved in DNA damage and repair pathways. Our evaluation of DNA repair genes revealed that temozolomide elicited an increase, while chlorpromazine, as well as connexin-43 silencing, a decrease in DNA repair gene expression in GBM cells. CONCLUSIONS Chlorpromazine potentiates the cytotoxic effects of the alkylating agent temozolomide through a mechanism involving downregulation of Cx43 expression and disruption of the cell cycle arrest essential for DNA repair processes. This finding suggests that chlorpromazine may be a potential therapeutic strategy to overcome TMZ resistance in GBM cells by inhibiting their DNA repair mechanisms.
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Affiliation(s)
- Paola Matarrese
- Center for Gender-Specific Medicine, Istituto Superiore di Sanità, 00161, Rome, Italy
| | - Michele Signore
- RPPA Unit, Proteomics Area, Core Facilities, Istituto Superiore di Sanità, 00161, Rome, Italy
| | - Barbara Ascione
- Center for Gender-Specific Medicine, Istituto Superiore di Sanità, 00161, Rome, Italy
| | - Giulia Fanelli
- Cellular Networks and Molecular Therapeutic Targets, Proteomics Unit, IRCCS-Regina Elena National Cancer Institute, Via Elio Chianesi 53, 00144, Rome, Italy
| | - Marco G Paggi
- Cellular Networks and Molecular Therapeutic Targets, Proteomics Unit, IRCCS-Regina Elena National Cancer Institute, Via Elio Chianesi 53, 00144, Rome, Italy.
| | - Claudia Abbruzzese
- Cellular Networks and Molecular Therapeutic Targets, Proteomics Unit, IRCCS-Regina Elena National Cancer Institute, Via Elio Chianesi 53, 00144, Rome, Italy.
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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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Quan Y, Du Y, Wu C, Gu S, Jiang JX. Connexin hemichannels regulate redox potential via metabolite exchange and protect lens against cellular oxidative damage. Redox Biol 2021; 46:102102. [PMID: 34474393 PMCID: PMC8408634 DOI: 10.1016/j.redox.2021.102102] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2021] [Revised: 08/10/2021] [Accepted: 08/11/2021] [Indexed: 11/23/2022] Open
Abstract
Increased oxidative stress contributes to cataract formation during aging. Anterior epithelial cells are a frontline antioxidant defense system with powerful capacities to maintain redox homeostasis and lens transparency. In this study, we report a new molecular mechanism of connexin (Cx) hemichannels (HCs) in lens epithelial cells to protect lens against oxidative stress. Our results showed haploinsufficiency of Cx43 elevated oxidative stress and susceptibility to cataracts in the mouse lens. Cx43 HCs opened in response to hydrogen peroxide (H2O2) or ultraviolet radiation (UVR) in human lens epithelium HLE-B3 cells, and this activation contributed to a cellular protective mechanism against oxidative stress-induced apoptotic cell death. Furthermore, we found that Cx43 HCs mediated the exchange of oxidants and antioxidants in lens epithelial cells undergoing oxidative stress. These transporting activities facilitated a reduction of intracellular reactive oxygen species (ROS) accumulation and maintained the intracellular glutathione (GSH) level through the exchange of redox metabolites and change of anti-oxidative gene expression. In addition, we show that Cx43 HCs can be regulated by the intracellular redox state and this regulation is mediated by residue Cys260 located at the Cx43 C-terminus. Together, our results demonstrate that Cx43 HCs activated by oxidative stress in the lens epithelial cells play a key role in maintaining redox homeostasis in lens under oxidative stress. Our findings contribute to advancing our understanding of oxidative stress induced lens disorders, such as age-related non-congenital cataracts.
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Affiliation(s)
- Yumeng Quan
- Department of Ophthalmology, First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi, China; Department of Biochemistry and Structural Biology, University of Texas Health Science Center, San Antonio, TX, USA
| | - Yu Du
- Department of Biochemistry and Structural Biology, University of Texas Health Science Center, San Antonio, TX, USA
| | - Changrui Wu
- Department of Biochemistry and Structural Biology, University of Texas Health Science Center, San Antonio, TX, USA
| | - Sumin Gu
- Department of Biochemistry and Structural Biology, University of Texas Health Science Center, San Antonio, TX, USA
| | - Jean X Jiang
- Department of Biochemistry and Structural Biology, University of Texas Health Science Center, San Antonio, TX, USA.
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Connexins in the Heart: Regulation, Function and Involvement in Cardiac Disease. Int J Mol Sci 2021; 22:ijms22094413. [PMID: 33922534 PMCID: PMC8122935 DOI: 10.3390/ijms22094413] [Citation(s) in RCA: 53] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Revised: 04/12/2021] [Accepted: 04/20/2021] [Indexed: 12/20/2022] Open
Abstract
Connexins are a family of transmembrane proteins that play a key role in cardiac physiology. Gap junctional channels put into contact the cytoplasms of connected cardiomyocytes, allowing the existence of electrical coupling. However, in addition to this fundamental role, connexins are also involved in cardiomyocyte death and survival. Thus, chemical coupling through gap junctions plays a key role in the spreading of injury between connected cells. Moreover, in addition to their involvement in cell-to-cell communication, mounting evidence indicates that connexins have additional gap junction-independent functions. Opening of unopposed hemichannels, located at the lateral surface of cardiomyocytes, may compromise cell homeostasis and may be involved in ischemia/reperfusion injury. In addition, connexins located at non-canonical cell structures, including mitochondria and the nucleus, have been demonstrated to be involved in cardioprotection and in regulation of cell growth and differentiation. In this review, we will provide, first, an overview on connexin biology, including their synthesis and degradation, their regulation and their interactions. Then, we will conduct an in-depth examination of the role of connexins in cardiac pathophysiology, including new findings regarding their involvement in myocardial ischemia/reperfusion injury, cardiac fibrosis, gene transcription or signaling regulation.
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Effects of Electroacupuncture on Ovarian Expression of the Androgen Receptor and Connexin 43 in Rats with Letrozole-Induced Polycystic Ovaries. EVIDENCE-BASED COMPLEMENTARY AND ALTERNATIVE MEDICINE 2020; 2020:3608062. [PMID: 32733580 PMCID: PMC7376399 DOI: 10.1155/2020/3608062] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/04/2020] [Revised: 05/28/2020] [Accepted: 06/19/2020] [Indexed: 11/23/2022]
Abstract
Background Polycystic ovarian syndrome (PCOS) occurs in women of reproductive age and is often characterized by reproductive and endocrine dysfunction. Androgens play a major role in PCOS, and previous studies reported abnormal expression of Connexin 43 (Cx43) in animal models of PCOS, suggesting an association of Cx43 with PCOS pathogenesis. Experimental and clinical evidence indicated that acupuncture may be a safe and effective approach for treating reproductive and endocrine disorders in women with PCOS. This study aimed to determine the effects of electroacupuncture (EA) on PCOS and its relationship with the expression of the androgen receptor (AR) and Cx43. Methods In total, 30 female Sprague Dawley rats (6 weeks old) were randomly divided into three groups: control group, letrozole (LE) group, and LE + EA group. Rats were administered LE solution (1.0 mg/kg) for 21 consecutive days to induce PCOS. For the LE + EA group, additional EA treatment was conducted (2 Hz, 20 min/d) with “Guanyuan” (CV3) for 14 consecutive days. After hematoxylin-eosin staining, the ovarian structure was observed with an optical microscope, and serum levels of the following hormones were examined via enzyme-linked immunosorbent assay (ELISA): testosterone (T), estradiol (E2), sex hormone-binding globulin (SHBG), follicle-stimulating hormone (FSH); luteinizing hormone (LH), insulin (INS), anti-Müllerian hormone (AMH), and inhibin B (INHB). Fasting blood glucose (FBG) levels were evaluated using glucose oxidase-peroxidase. Ovarian mRNA and protein expressions of AR and Cx43 were determined by real-time RT-PCR and Western blot analysis. Results EA was found to restore the cyclicity and ovarian morphology in the PCOS rat model. Serum derived from the LE + EA group showed significant decreases in the levels of T, free androgen index (FAI), LH, LH/FSH ratio, AMH, INHB, and fasting serum insulin (FINS), and significant increases in the levels of E2, FSH, and SHBG. Western blot analysis showed a decreased protein expression of ovarian AR and Cx43; real-time RT-PCR showed reduced expression of ovarian mRNA levels of AR and Cx43. Conclusions In conclusion, our results showed that EA can ease hyperandrogenism and polycystic ovary morphology in PCOS rats. Furthermore, EA counteracted the letrozole-induced upregulation of AR and Cx43. These results suggested that acupuncture can break the vicious cycle initiated by excessive androgen secretion and may be an effective treatment method for improving the reproductive and endocrine dysfunction caused by PCOS.
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Abstract
Of the 21 members of the connexin family, 4 (Cx37, Cx40, Cx43, and Cx45) are expressed in the endothelium and/or smooth muscle of intact blood vessels to a variable and dynamically regulated degree. Full-length connexins oligomerize and form channel structures connecting the cytosol of adjacent cells (gap junctions) or the cytosol with the extracellular space (hemichannels). The different connexins vary mainly with regard to length and sequence of their cytosolic COOH-terminal tails. These COOH-terminal parts, which in the case of Cx43 are also translated as independent short isoforms, are involved in various cellular signaling cascades and regulate cell functions. This review focuses on channel-dependent and -independent effects of connexins in vascular cells. Channels play an essential role in coordinating and synchronizing endothelial and smooth muscle activity and in their interplay, in the control of vasomotor actions of blood vessels including endothelial cell reactivity to agonist stimulation, nitric oxide-dependent dilation, and endothelial-derived hyperpolarizing factor-type responses. Further channel-dependent and -independent roles of connexins in blood vessel function range from basic processes of vascular remodeling and angiogenesis to vascular permeability and interactions with leukocytes with the vessel wall. Together, these connexin functions constitute an often underestimated basis for the enormous plasticity of vascular morphology and function enabling the required dynamic adaptation of the vascular system to varying tissue demands.
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Affiliation(s)
- Ulrich Pohl
- Walter-Brendel-Centre of Experimental Medicine, University Hospital, LMU Munich, Planegg-Martinsried, Germany; Biomedical Centre, Cardiovascular Physiology, LMU Munich, Planegg-Martinsried, Germany; German Centre for Cardiovascular Research, Partner Site Munich Heart Alliance, Munich, Germany; and Munich Cluster for Systems Neurology (SyNergy), Munich, Germany
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Gamma Radiation-Induced Disruption of Cellular Junctions in HUVECs Is Mediated through Affecting MAPK/NF- κB Inflammatory Pathways. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2019; 2019:1486232. [PMID: 31467629 PMCID: PMC6701340 DOI: 10.1155/2019/1486232] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/22/2019] [Revised: 04/08/2019] [Accepted: 07/02/2019] [Indexed: 12/15/2022]
Abstract
Ionizing radiation-induced cardiovascular diseases (CVDs) have been well documented. However, the mechanisms of CVD genesis are still not fully understood. In this study, human umbilical vein endothelial cells (HUVECs) were exposed to gamma irradiation at different doses ranging from 0.2 Gy to 5 Gy. Cell viability, migration ability, permeability, oxidative and nitrosative stresses, inflammation, and nuclear factor kappa-light-chain-enhancer of activated B cell (NF-κB) pathway activation were evaluated postirradiation. It was found that gamma irradiation at doses ranging from 0.5 Gy to 5 Gy inhibited the migration ability of HUVECs without any significant effects on cell viability at 6 h and 24 h postirradiation. The decreased transendothelial electrical resistance (TEER), increased permeability, and disruption of cellular junctions were observed in HUVECs after gamma irradiation accompanied by the lower levels of junction-related proteins such as ZO-1, occludin, vascular endothelial- (VE-) cadherin, and connexin 40. The enhanced oxidative and nitrosative stresses, e.g., ROS and NO2 - levels and inflammatory cytokines IL-6 and TNF-α were demonstrated in HUVECs after gamma irradiation. Western blot results showed that protein levels of mitogen-activated protein kinase (MAPK) pathway molecules p38, p53, p21, and p27 increased after gamma irradiation, which further induced the activation of the NF-κB pathway. BAY 11-7085, an inhibitor of NF-κB activation, was demonstrated to partially block the effects of gamma radiation in HUVECs examined by TEER and FITC-dextran permeability assay. We therefore concluded that the gamma irradiation-induced disruption of cellular junctions in HUVECs was through the inflammatory MAPK/NF-κB signaling pathway.
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Trotta MC, Ferraro B, Messina A, Panarese I, Gulotta E, Nicoletti GF, D'Amico M, Pieretti G. Telmisartan cardioprotects from the ischaemic/hypoxic damage through a miR-1-dependent pathway. J Cell Mol Med 2019; 23:6635-6645. [PMID: 31369209 PMCID: PMC6787508 DOI: 10.1111/jcmm.14534] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2019] [Revised: 05/27/2019] [Accepted: 06/24/2019] [Indexed: 01/01/2023] Open
Abstract
The aim of this study was to investigate whether telmisartan protects the heart from the ischaemia/reperfusion damage through a local microRNA‐1 modulation. Studies on the myocardial ischaemia/reperfusion injury in vivo and on the cardiomyocyte hypoxia/reoxygenation damage in vitro were done. In vivo, male Sprague‐Dawley rats administered for 3 weeks with telmisartan 12 mg/kg/d by gastric gavage underwent ischaemia/reperfusion of the left descending coronary artery. In these rats, infarct size measurement, ELISA, immunohistochemistry (IHC) and reverse transcriptase real‐time polymerase chain reaction showed that expressions of connexin 43, potassium voltage‐gated channel subfamily Q member 1 and the protein Bcl‐2 were significantly increased by telmisartan in the reperfused myocardium, paralleled by microRNA‐1 down‐regulation. In vitro, the transfection of cardiomyocytes with microRNA‐1 reduced the expressions of connexin 43, potassium voltage‐gated channel subfamily Q member 1 and Bcl‐2 in the cells. Telmisartan (50 µmol/L) 60 minutes before hypoxia/reoxygenation, while not affecting the levels of miR‐1 in transfected cells in normoxic condition, almost abolished the increment of miR‐1 induced by the hypoxia/reoxygenation to transfected cells. All together, telmisartan cardioprotected against the myocardial damage through the microRNA‐1 modulation, and consequent modifications of its downstream target connexin 43, potassium voltage‐gated channel subfamily Q member 1 and Bcl‐2.
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Affiliation(s)
- Maria Consiglia Trotta
- Department of Experimental Medicine, University of Campania 'Luigi Vanvitelli', Naples, Italy
| | - Bartolo Ferraro
- Department of Experimental Medicine, University of Campania 'Luigi Vanvitelli', Naples, Italy
| | - Antonietta Messina
- Department of Experimental Medicine, University of Campania 'Luigi Vanvitelli', Naples, Italy
| | - Iacopo Panarese
- Department of Mental and Physical Health and Preventive Medicine, University of Campania 'Luigi Vanvitelli', Naples, Italy
| | - Eliana Gulotta
- Department of Surgical, Oncological and Stomatological Disciplines, University of Palermo, Palermo, Italy
| | - Giovanni Francesco Nicoletti
- Multidisciplinary Department of Surgical and Dental Specialties, University of Campania 'Luigi Vanvitelli', Naples, Italy
| | - Michele D'Amico
- Department of Experimental Medicine, University of Campania 'Luigi Vanvitelli', Naples, Italy
| | - Gorizio Pieretti
- Multidisciplinary Department of Surgical and Dental Specialties, University of Campania 'Luigi Vanvitelli', Naples, Italy
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Pogoda K, Kameritsch P, Mannell H, Pohl U. Connexins in the control of vasomotor function. Acta Physiol (Oxf) 2019; 225:e13108. [PMID: 29858558 DOI: 10.1111/apha.13108] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2017] [Revised: 05/25/2018] [Accepted: 05/28/2018] [Indexed: 12/13/2022]
Abstract
Vascular endothelial cells, as well as smooth muscle cells, show heterogeneity with regard to their receptor expression and reactivity. For the vascular wall to act as a functional unit, the various cells' responses require integration. Such an integration is not only required for a homogeneous response of the vascular wall, but also for the vasomotor behaviour of consecutive segments of the microvascular arteriolar tree. As flow resistances of individual sections are connected in series, sections require synchronization and coordination to allow effective changes of conductivity and blood flow. A prerequisite for the local coordination of individual vascular cells and different sections of an arteriolar tree is intercellular communication. Connexins are involved in a dual manner in this coordination. (i) By forming gap junctions between cells, they allow an intercellular exchange of signalling molecules and electrical currents. In particular, the spread of electrical currents allows for coordination of cell responses over longer distances. (ii) Connexins are able to interact with other proteins to form signalling complexes. In this way, they can modulate and integrate individual cells' responses also in a channel-independent manner. This review outlines mechanisms allowing the vascular connexins to exert their coordinating function and to regulate the vasomotor reactions of blood vessels both locally, and in vascular networks. Wherever possible, we focus on the vasomotor behaviour of small vessels and arterioles which are the main vessels determining vascular resistance, blood pressure and local blood flow.
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Affiliation(s)
- K. Pogoda
- Walter-Brendel-Centre of Experimental Medicine; University Hospital; LMU Munich; Munich Germany
- Biomedical Center; Cardiovascular Physiology; LMU Munich; Munich Germany
- DZHK (German Center for Cardiovascular Research); Partner Site Munich Heart Alliance; Munich Germany
| | - P. Kameritsch
- Walter-Brendel-Centre of Experimental Medicine; University Hospital; LMU Munich; Munich Germany
- Biomedical Center; Cardiovascular Physiology; LMU Munich; Munich Germany
- DZHK (German Center for Cardiovascular Research); Partner Site Munich Heart Alliance; Munich Germany
| | - H. Mannell
- Walter-Brendel-Centre of Experimental Medicine; University Hospital; LMU Munich; Munich Germany
- Biomedical Center; Cardiovascular Physiology; LMU Munich; Munich Germany
| | - U. Pohl
- Walter-Brendel-Centre of Experimental Medicine; University Hospital; LMU Munich; Munich Germany
- Biomedical Center; Cardiovascular Physiology; LMU Munich; Munich Germany
- DZHK (German Center for Cardiovascular Research); Partner Site Munich Heart Alliance; Munich Germany
- Munich Cluster for Systems Neurology (SyNergy); Munich Germany
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Vuong NH, Cook DP, Forrest LA, Carter LE, Robineau-Charette P, Kofsky JM, Hodgkinson KM, Vanderhyden BC. Single-cell RNA-sequencing reveals transcriptional dynamics of estrogen-induced dysplasia in the ovarian surface epithelium. PLoS Genet 2018; 14:e1007788. [PMID: 30418965 PMCID: PMC6258431 DOI: 10.1371/journal.pgen.1007788] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2018] [Revised: 11/26/2018] [Accepted: 10/25/2018] [Indexed: 12/30/2022] Open
Abstract
Estrogen therapy increases the risk of ovarian cancer and exogenous estradiol accelerates the onset of ovarian cancer in mouse models. Both in vivo and in vitro, ovarian surface epithelial (OSE) cells exposed to estradiol develop a subpopulation that loses cell polarity, contact inhibition, and forms multi-layered foci of dysplastic cells with increased susceptibility to transformation. Here, we use single-cell RNA-sequencing to characterize this dysplastic subpopulation and identify the transcriptional dynamics involved in its emergence. Estradiol-treated cells were characterized by up-regulation of genes associated with proliferation, metabolism, and survival pathways. Pseudotemporal ordering revealed that OSE cells occupy a largely linear phenotypic spectrum that, in estradiol-treated cells, diverges towards cell state consistent with the dysplastic population. This divergence is characterized by the activation of various cancer-associated pathways including an increase in Greb1 which was validated in fallopian tube epithelium and human ovarian cancers. Taken together, this work reveals possible mechanisms by which estradiol increases epithelial cell susceptibility to tumour initiation.
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Affiliation(s)
- Nhung H. Vuong
- Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, Canada
- Cancer Therapeutics Program, Ottawa Hospital Research Institute, Ottawa, Canada
| | - David P. Cook
- Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, Canada
- Cancer Therapeutics Program, Ottawa Hospital Research Institute, Ottawa, Canada
| | - Laura A. Forrest
- Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, Canada
- Cancer Therapeutics Program, Ottawa Hospital Research Institute, Ottawa, Canada
| | - Lauren E. Carter
- Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, Canada
- Cancer Therapeutics Program, Ottawa Hospital Research Institute, Ottawa, Canada
| | - Pascale Robineau-Charette
- Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, Canada
- Cancer Therapeutics Program, Ottawa Hospital Research Institute, Ottawa, Canada
| | - Joshua M. Kofsky
- Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, Canada
- Cancer Therapeutics Program, Ottawa Hospital Research Institute, Ottawa, Canada
| | - Kendra M. Hodgkinson
- Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, Canada
- Cancer Therapeutics Program, Ottawa Hospital Research Institute, Ottawa, Canada
| | - Barbara C. Vanderhyden
- Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, Canada
- Cancer Therapeutics Program, Ottawa Hospital Research Institute, Ottawa, Canada
- * E-mail:
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Abrams CK, Peinado A, Mahmoud R, Bocarsly M, Zhang H, Chang P, Botello-Smith WM, Freidin MM, Luo Y. Alterations at Arg 76 of human connexin 46, a residue associated with cataract formation, cause loss of gap junction formation but preserve hemichannel function. Am J Physiol Cell Physiol 2018; 315:C623-C635. [PMID: 30044662 DOI: 10.1152/ajpcell.00157.2018] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The connexins are members of a family of integral membrane proteins that form gap junction channels between apposed cells and/or hemichannels across the plasma membranes. The importance of the arginine at position 76 (Arg76) in the structure and/or function of connexin 46 (Cx46) is highlighted by its conservation across the entire connexin family and the occurrence of pathogenic mutations at this (or the corresponding homologous) residue in a number of human diseases. Two mutations at Arg76 in Cx46 are associated with cataracts in humans, highlighting the importance of this residue. We examined the expression levels and macroscopic and single-channel properties of human Cx46 and compared them with those for two pathogenic mutants, namely R76H and R76G. To gain further insight into the role of charge at this position, we generated two additional nonnaturally occurring mutants, R76K (charge conserving) and R76E (charge inverting). We found that, when expressed exogenously in Neuro2a cells, all four mutants formed membrane hemichannels, inducing membrane permeability at levels comparable to those recorded in cells expressing the wild-type Cx46. In contrast, the number of gap-junction plaques and the magnitude of junctional coupling were reduced by all four mutations. To gain further insight into the role of Arg76 in the function of Cx46, we performed homology modeling of Cx46 and in silico mutagenesis of Arg76 to Gly, His, or Glu. Our studies suggest that the loss of interprotomeric interactions has a significant effect on the extracellular domain conformation and dynamics, thus affecting the hemichannel docking required for formation of cell-cell channels.
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Affiliation(s)
- Charles K Abrams
- Department of Neurology and Rehabilitation, University of Illinois at Chicago College of Medicine , Chicago, Illinois
- Department of Neurology State University of New York Downstate Medical Center , Brooklyn New York
| | - Alejandro Peinado
- Department of Neurology and Rehabilitation, University of Illinois at Chicago College of Medicine , Chicago, Illinois
| | - Rola Mahmoud
- Department of Neurology State University of New York Downstate Medical Center , Brooklyn New York
| | - Matan Bocarsly
- Department of Neurology State University of New York Downstate Medical Center , Brooklyn New York
| | - Han Zhang
- Department of Pharmaceutical Sciences, College of Pharmacy, Western University of Health Sciences , Pomona, California
| | - Paul Chang
- Department of Pharmaceutical Sciences, College of Pharmacy, Western University of Health Sciences , Pomona, California
| | - Wesley M Botello-Smith
- Department of Pharmaceutical Sciences, College of Pharmacy, Western University of Health Sciences , Pomona, California
| | - Mona M Freidin
- Department of Neurology and Rehabilitation, University of Illinois at Chicago College of Medicine , Chicago, Illinois
- Department of Neurology State University of New York Downstate Medical Center , Brooklyn New York
| | - Yun Luo
- Department of Pharmaceutical Sciences, College of Pharmacy, Western University of Health Sciences , Pomona, California
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Connexin43 and AMPK Have Essential Role in Resistance to Oxidative Stress Induced Necrosis. BIOMED RESEARCH INTERNATIONAL 2017; 2017:3962173. [PMID: 29279848 PMCID: PMC5723946 DOI: 10.1155/2017/3962173] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/20/2017] [Accepted: 10/03/2017] [Indexed: 01/17/2023]
Abstract
Reactive oxygen species (ROS) induced oxidative stress leads to cell damage and neurological disorders in astrocytes. The gap junction protein connexin43 (Cx43) could form intercellular channels in astrocytes and the expression of Cx43 plays an important role in protecting the cells from damage. In the present study, we investigated the contribution of Cx43 to astrocytic necrosis induced by the ROS hydrogen peroxide (H2O2) and the mechanism by which AMPK was involved in this process. Fluorescence microscopy, flow cytometry, and western blot were used quantitatively and qualitatively to determine the cell apoptosis, necrosis, and protein expression. Lack of Cx43 expression or blockage of Cx43 channels resulted in increased H2O2-induced astrocytic necrosis, supporting a cell protective effect of functional Cx43 channels. Our data suggest that AMPK is important for Cx43-mediated ROS resistance. Inhibition of AMPK activation results in reduction of necrosis and ROS production. Taken together, our findings suggest that the role of Cx43 in response to H2O2 stress is dependent on the activation of AMPK signaling pathways and regulates ROS production and cell necrosis.
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Pinto BI, Pupo A, García IE, Mena-Ulecia K, Martínez AD, Latorre R, Gonzalez C. Calcium binding and voltage gating in Cx46 hemichannels. Sci Rep 2017; 7:15851. [PMID: 29158540 PMCID: PMC5696461 DOI: 10.1038/s41598-017-15975-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2016] [Accepted: 10/24/2017] [Indexed: 12/26/2022] Open
Abstract
The opening of connexin (Cx) hemichannels in the membrane is tightly regulated by calcium (Ca2+) and membrane voltage. Electrophysiological and atomic force microscopy experiments indicate that Ca2+ stabilizes the hemichannel closed state. However, structural data show that Ca2+ binding induces an electrostatic seal preventing ion transport without significant structural rearrangements. In agreement with the closed-state stabilization hypothesis, we found that the apparent Ca2+ sensitivity is increased as the voltage is made more negative. Moreover, the voltage and Ca2+ dependence of the channel kinetics indicate that the voltage sensor movement and Ca2+ binding are allosterically coupled. An allosteric kinetic model in which the Ca2+ decreases the energy necessary to deactivate the voltage sensor reproduces the effects of Ca2+ and voltage in Cx46 hemichannels. In agreement with the model and suggesting a conformational change that narrows the pore, Ca2+ inhibits the water flux through Cx hemichannels. We conclude that Ca2+ and voltage act allosterically to stabilize the closed conformation of Cx46 hemichannels.
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Affiliation(s)
- Bernardo I Pinto
- Centro Interdisciplinario de Neurociencias de Valparaíso, Universidad de Valparaíso, Valparaíso, Chile
| | - Amaury Pupo
- Centro Interdisciplinario de Neurociencias de Valparaíso, Universidad de Valparaíso, Valparaíso, Chile
| | - Isaac E García
- Centro Interdisciplinario de Neurociencias de Valparaíso, Universidad de Valparaíso, Valparaíso, Chile
- Facultad de Odontología, Universidad de Valparaíso, Valparaíso, Chile
| | - Karel Mena-Ulecia
- Centro Interdisciplinario de Neurociencias de Valparaíso, Universidad de Valparaíso, Valparaíso, Chile
| | - Agustín D Martínez
- Centro Interdisciplinario de Neurociencias de Valparaíso, Universidad de Valparaíso, Valparaíso, Chile
| | - Ramón Latorre
- Centro Interdisciplinario de Neurociencias de Valparaíso, Universidad de Valparaíso, Valparaíso, Chile.
| | - Carlos Gonzalez
- Centro Interdisciplinario de Neurociencias de Valparaíso, Universidad de Valparaíso, Valparaíso, Chile.
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Pronin S, Koh CH, Hughes M. Effects of Ultraviolet Radiation on Glioma: Systematic Review. J Cell Biochem 2017; 118:4063-4071. [PMID: 28407299 DOI: 10.1002/jcb.26061] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2017] [Accepted: 04/12/2017] [Indexed: 01/05/2023]
Abstract
Glioblastoma multiforme is the most aggressive primary brain tumor. Treatment is largely palliative, with current strategies unable to prevent inevitable tumor recurrence. Implantable micro-electromechanical systems are becoming more feasible for the management of several human diseases. These systems may have a role in detecting tumor recurrence and delivering localized therapies. One potential therapeutic tool is ultraviolet (UV) light. This systematic review assesses the effects of UV light on glioma cells. A total of 47 publications are included. The large majority were in vitro experiments conducted on human glioblastoma cell lines in monolayer. In these cells, UV light was shown to induce apoptosis and the expression of genes or activation of proteins that modulate cell death, repair, and proliferation. The nature and magnitude of cellular response varied by UV wavelength, dose, cell line, and time after irradiation. UVC (wavelength 100-280 nm) was most effective at inducing apoptosis, and this effect was dose dependent. The included studies had varied methodologies, complicating reconciliation of results. Further work will be required to determine the best regime of UV irradiation for therapeutic use. J. Cell. Biochem. 118: 4063-4071, 2017. © 2017 Wiley Periodicals, Inc.
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Affiliation(s)
- Savva Pronin
- Edinburgh Medical School, University of Edinburgh, Edinburgh, UK
| | - Chan Hee Koh
- Edinburgh Medical School, University of Edinburgh, Edinburgh, UK
| | - Mark Hughes
- Translational Neurosurgery Unit, Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, UK
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15
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Rodríguez-Sinovas A, Ruiz-Meana M, Denuc A, García-Dorado D. Mitochondrial Cx43, an important component of cardiac preconditioning. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2017. [PMID: 28642043 DOI: 10.1016/j.bbamem.2017.06.011] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Connexin 43 (Cx43) forms gap junction channels that are essential for the propagation of electrical depolarization in cardiomyocytes, but also with important roles in the pathophysiology of reperfusion injury. However, more recent studies have shown that Cx43 has also important functions independent from intercellular communication between adjacent cardiomyocytes. Some of these actions have been related to the presence of Cx43 in the mitochondria of these cells (mitoCx43). The functions of mitoCx43 have not been completely elucidated, but there is strong evidence indicating that mitoCx43 modulates mitochondrial respiration at respiratory complex I, production of radical oxygen species and ATP synthesis. These functions of mitoCx43 modulate mitochondrial and cellular tolerance to reperfusion after prolonged ischemia and are necessary for the cardioprotective effect of ischemic preconditioning. In the present review article we discuss available knowledge on these functions of mitoCx43 in relation to reperfusion injury, the molecular mechanisms involved and explore the possibility that mitoCx43 may constitute a new pharmacological target in patients with ST-segment elevation myocardial infarction (STEMI). This article is part of a Special Issue entitled: Gap Junction Proteins edited by Jean Claude Herve.
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Affiliation(s)
- Antonio Rodríguez-Sinovas
- Cardiovascular Diseases Research Group, Department of Cardiology, Vall d'Hebron University Hospital and Research Institute, Universitat Autònoma de Barcelona, Barcelona, Spain; Centro de Investigación Biomédica en Red sobre Enfermedades Cardiovasculares (CIBERCV), Spain
| | - Marisol Ruiz-Meana
- Cardiovascular Diseases Research Group, Department of Cardiology, Vall d'Hebron University Hospital and Research Institute, Universitat Autònoma de Barcelona, Barcelona, Spain; Centro de Investigación Biomédica en Red sobre Enfermedades Cardiovasculares (CIBERCV), Spain
| | - Amanda Denuc
- Cardiovascular Diseases Research Group, Department of Cardiology, Vall d'Hebron University Hospital and Research Institute, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - David García-Dorado
- Cardiovascular Diseases Research Group, Department of Cardiology, Vall d'Hebron University Hospital and Research Institute, Universitat Autònoma de Barcelona, Barcelona, Spain; Centro de Investigación Biomédica en Red sobre Enfermedades Cardiovasculares (CIBERCV), Spain.
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16
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Enhanced gap junction intercellular communication inhibits catabolic and pro-inflammatory responses in tenocytes against heat stress. J Cell Commun Signal 2017; 11:369-380. [PMID: 28601938 DOI: 10.1007/s12079-017-0397-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2017] [Accepted: 05/28/2017] [Indexed: 12/17/2022] Open
Abstract
Elevation of tendon core temperature during severe activity is well known. However, its effects on tenocyte function have not been studied in detail. The present study tested a hypothesis that heat stimulation upregulates tenocyte catabolism, which can be modulated by the inhibition or the enhancement of gap junction intercellular communication (GJIC). Tenocytes isolated from rabbit Achilles tendons were subjected to heat stimulation at 37 °C, 41 °C or 43 °C for 30 min, and changes in cell viability, gene expressions and GJIC were examined. It was found that GJIC exhibited no changes by the stimulation even at 43 °C, but cell viability was decreased and catabolic and proinflammatory gene expressions were upregulated. Inhibition of GJIC demonstrated further upregulated catabolic and proinflammatory gene expressions. In contrast, enhanced GJIC, resulting from forced upregulation of connexin 43 gene, counteracted the heat-induced upregulation of catabolic and proinflammatory genes. These findings suggest that the temperature rise in tendon core could upregulate catabolic and proinflammatory activities, potentially leading to the onset of tendinopathy, and such upregulations could be suppressed by the enhancement of GJIC. Therefore, to prevent tendon injury at an early stage from becoming chronic injury, tendon core temperature and GJIC could be targets for post-activity treatments.
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17
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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: 137] [Impact Index Per Article: 19.6] [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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18
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Ogawa E, Kurotsu M, Arai T. Irradiance dependence of the conduction block of an in vitro cardiomyocyte wire. Photodiagnosis Photodyn Ther 2017; 19:93-97. [PMID: 28502877 DOI: 10.1016/j.pdpdt.2017.05.008] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2017] [Revised: 04/25/2017] [Accepted: 05/09/2017] [Indexed: 11/30/2022]
Abstract
BACKGROUND To obtain therapeutic condition precisely by in vitro experiment, we studied the irradiance dependence of the electrical conduction blockage caused by a photodynamic reaction using a high extracellular concentration of talaporfin sodium on a novel in vitro cardiomyocyte electrical conduction wire. METHODS The cardiomyocyte wires were constructed on patterned cultivation cover glass, which had cultivation areas 60μm in width, and a maximum length of 10mm. The talaporfin sodium concentration was set to 20μg/mL. The photodynamic reaction with a high extracellular photosensitizer concentration was performed with a short time interval (approximately 15min) between photosensitizer exposure and irradiation. A 663-nm laser was applied to the cardiomyocyte wire, and the irradiance was varied between 3 and 120mW/cm2. The cardiomyocyte electrical conduction was evaluated using the cross-correlation function of intracellular Ca2+ probe fluorescence brightness from an upper and lower section outside the laser irradiation area of a wire every 10s, which lasted up to 600s. RESULTS The onset of electrical conduction blockage was defined by an 85% decrease in the cross-correlation function, compared with its initial value. The time for the electrical conduction blockage decreased from 600 to 300s as the irradiance was increased. Also, the probability of electrical conduction blockage was found to increase with increasing irradiance. CONCLUSIONS We found a strong dependence on the irradiance for the time and probability of electrical conduction blockage.
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Affiliation(s)
- Emiyu Ogawa
- School of Fundamental Science and Technology, Graduate School of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223-8522, Japan.
| | - Mariko Kurotsu
- School of Fundamental Science and Technology, Graduate School of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223-8522, Japan
| | - Tsunenori Arai
- School of Fundamental Science and Technology, Graduate School of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223-8522, Japan; School of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223-8522, Japan
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19
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Wu W, Fan L, Bao Z, Zhang Y, Peng Y, Shao M, Xiang Y, Zhang X, Wang Q, Tao L. The cytoplasmic translocation of Cx32 mediates cisplatin resistance in ovarian cancer cells. Biochem Biophys Res Commun 2017; 487:292-299. [PMID: 28412364 DOI: 10.1016/j.bbrc.2017.04.053] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2017] [Accepted: 04/11/2017] [Indexed: 01/09/2023]
Abstract
Ovarian cancer is the most lethal gynecologic malignancy, and cisplatin is one of the first-line chemotherapeutic agents. However, acquired cisplatin resistance prevents the successful treatment of patients with ovarian cancer. Gap junction (GJ) and connexin (Cx) are closely related to tumor formation, but the relationship between cisplatin resistance and GJ or Cx are undetermined. In this study, we established the cisplatin-resistant human ovarian cancer cell line A2780-CDDP. Here we showed that cisplatin resistance was correlated to the loss of GJ and the upregulation of Cx32 expression. Enhancing GJ in A2780-CDDP cells could increase the apoptotic response to cisplatin treatment. Furthermore, although Cx32 expression was increased in A2780-CDDP cells, it was more localized to the cytoplasm rather than in the membrane, and knockdown of Cx32 in A2780-CDDP cells sensitized them to cisplatin treatment. In summary, Cx32 is involved in cisplatin resistance, and cytoplasmic Cx32 plays an important role in chemoresistance.
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Affiliation(s)
- Weili Wu
- Department of Pharmacology, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou 510080, People's Republic of China
| | - Lixia Fan
- Department of Pharmacology, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou 510080, People's Republic of China
| | - Zeqing Bao
- Zhaoqing Medical College Pharmacology Teaching and Research Section, Zhaoqing 526020, People's Republic of China
| | - Yu Zhang
- Department of Pharmacology, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou 510080, People's Republic of China
| | - Yuexia Peng
- Department of Pharmacology, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou 510080, People's Republic of China
| | - Min Shao
- Department of Pharmacology, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou 510080, People's Republic of China
| | - Yuke Xiang
- Department of Pharmacology, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou 510080, People's Republic of China
| | - Xiaomin Zhang
- Department of Pharmacology, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou 510080, People's Republic of China
| | - Qin Wang
- Department of Pharmacology, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou 510080, People's Republic of China
| | - Liang Tao
- Department of Pharmacology, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou 510080, People's Republic of China.
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20
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Kim YJ, Kim J, Kim YS, Shin B, Choo OS, Lee JJ, Choung YH. Connexin 43 Acts as a Proapoptotic Modulator in Cisplatin-Induced Auditory Cell Death. Antioxid Redox Signal 2016; 25:623-636. [PMID: 27122099 DOI: 10.1089/ars.2015.6412] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
AIMS Gap junction coupling is known to play a role in intercellular communication by the Good Samaritan effect or bystander effect. Nonjunctional connexins (Cxs) may also play certain gap junction-independent roles in cell death or survival. The purpose of the present study was to investigate the role of junctional and nonjunctional Cxs in ototoxic drug-induced auditory cell death by focusing on Cx43 in the cochlea. RESULTS Nonjunctional Cx43 conditions were prepared by low confluence culture (5 × 103/cm2) or a trafficking inhibitor, brefeldin A (BFA), in auditory cells, and short lengthened Cx43s with amino-terminal (NT; amino acids 1-256) or carboxy-terminal (CT; amino acids 257-382) were transfected into Cx-deficient HeLa cells to avoid gap junction formation. Knockdown of nonchannel Cx43 (small interfering RNA [siRNA]) inhibited Cis-diamminedichloroplatinum (cisplatin)-induced cell death regardless of gap junction formation; however, a gap junction blocker, 18 alpha-glycyrrhetinic acid (18α-GA), showed inhibitory effect only under the junctional condition. BFA did not show any additive influence on the inhibitory effect of siRNA Cx43. Shortened Cx43-transfected HeLa cells also resulted in a significant increase in cell death under cisplatin. In the animal studies with cisplatin-treated rats, hearing thresholds of auditory brainstem response were significantly preserved by a gap junction blocker, carbenoxolone, showing much more preserved stereocilia of hair cells in scanning electron microscopic findings. Innovation and Conclusion: Cx43 plays a proapoptotic role in cisplatin-induced auditory cell death in both junctional and nonjunctional conditions. Targeting the Cx-mediated signaling control may be helpful in designing new therapeutic strategies for drug-induced ototoxicity. Antioxid. Redox Signal. 25, 623-636.
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Affiliation(s)
- Yeon Ju Kim
- 1 Department of Otolaryngology, Ajou University School of Medicine , Suwon, Republic of Korea
| | - Jangho Kim
- 2 Department of Rural and Biosystems Engineering, Chonnam National University , Gwangju, Republic of Korea
| | - Young Sun Kim
- 1 Department of Otolaryngology, Ajou University School of Medicine , Suwon, Republic of Korea
| | - Beomyong Shin
- 3 Department of Medical Sciences, The Graduate School, Ajou University , Suwon, Republic of Korea
| | - Oak-Sung Choo
- 1 Department of Otolaryngology, Ajou University School of Medicine , Suwon, Republic of Korea
| | - Jong Joo Lee
- 1 Department of Otolaryngology, Ajou University School of Medicine , Suwon, Republic of Korea
| | - Yun-Hoon Choung
- 1 Department of Otolaryngology, Ajou University School of Medicine , Suwon, Republic of Korea.,3 Department of Medical Sciences, The Graduate School, Ajou University , Suwon, Republic of Korea
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González-Nieto D, Chang KH, Fasciani I, Nayak R, Fernandez-García L, Barrio LC, Cancelas JA. Connexins: Intercellular Signal Transmitters in Lymphohematopoietic Tissues. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2015; 318:27-62. [PMID: 26315883 DOI: 10.1016/bs.ircmb.2015.06.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Life-long hematopoietic demands are met by a pool of hematopoietic stem cells (HSC) with self-renewal and multipotential differentiation ability. Humoral and paracrine signals from the bone marrow (BM) hematopoietic microenvironment control HSC activity. Cell-to-cell communication through connexin (Cx) containing gap junctions (GJs) allows pluricellular coordination and synchronization through transfer of small molecules with messenger activity. Hematopoietic and surrounding nonhematopoietic cells communicate each other through GJs, which regulate fetal and postnatal HSC content and function in hematopoietic tissues. Traffic of HSC between peripheral blood and BM is also dependent on Cx proteins. Cx mutations are associated with human disease and hematopoietic dysfunction and Cx signaling may represent a target for therapeutic intervention. In this review, we illustrate and highlight the importance of Cxs in the regulation of hematopoietic homeostasis under normal and pathological conditions.
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Affiliation(s)
- Daniel González-Nieto
- Unit of Cellular and Animal Models, Center for Biomedical Technology, Universidad Politécnica de Madrid, Madrid, Spain; Biomedical Research Networking Center in Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN), Madrid, Spain
| | - Kyung-Hee Chang
- Division of Experimental Hematology and Cancer Biology, Children's Hospital Medical Center, University of Cincinnati College of Medicine, Cincinnati, OH, USA; Hoxworth Blood Center, University of Cincinnati, Cincinnati, OH, USA
| | - Ilaria Fasciani
- Unit of Experimental Neurology, Hospital Ramon y Cajal, Madrid, Spain
| | - Ramesh Nayak
- Division of Experimental Hematology and Cancer Biology, Children's Hospital Medical Center, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Laura Fernandez-García
- Unit of Cellular and Animal Models, Center for Biomedical Technology, Universidad Politécnica de Madrid, Madrid, Spain
| | - Luis C Barrio
- Unit of Experimental Neurology, Hospital Ramon y Cajal, Madrid, Spain
| | - José A Cancelas
- Division of Experimental Hematology and Cancer Biology, Children's Hospital Medical Center, University of Cincinnati College of Medicine, Cincinnati, OH, USA; Hoxworth Blood Center, University of Cincinnati, Cincinnati, OH, USA
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Freidin M, Asche-Godin S, Abrams CK. Gene expression profiling studies in regenerating nerves in a mouse model for CMT1X: uninjured Cx32-knockout peripheral nerves display expression profile of injured wild type nerves. Exp Neurol 2015; 263:339-49. [PMID: 25447941 PMCID: PMC4262134 DOI: 10.1016/j.expneurol.2014.10.014] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2014] [Revised: 10/13/2014] [Accepted: 10/18/2014] [Indexed: 11/20/2022]
Abstract
X-linked Charcot-Marie-Tooth disease (CMT1X) is an inherited peripheral neuropathy caused by mutations in GJB1, the human gene for Connexin32 (Cx32). This present study uses Ilumina Ref8-v2 BeadArray to examine the expression profiles of injured and uninjured sciatic nerves at 5, 7, and 14 days post-crush injury (dpi) from Wild Type (WT) and Cx32-knockout (Cx32KO) mice to identify the genes and signaling pathways that are dysregulated in the absence of Schwann cell Cx32. Given the assumption that loss of Schwann cell Cx32 disrupts the regeneration and maintenance of myelinated nerve leading to a demyelinating neuropathy in CMT1X, we initially hypothesized that nerve crush injury would result in significant increases in differential gene expression in Cx32KO mice relative to WT nerves. However, microarray analysis revealed a striking collapse in the number of differentially expressed genes at 5 and 7 dpi in Cx32KO nerves relative to WT, while uninjured and 14 dpi time points showed large numbers of differentially regulated genes. Further comparisons within each genotype showed limited changes in Cx32KO gene expression following crush injury when compared to uninjured Cx32KO nerves. By contrast, WT nerves exhibited robust changes in gene expression at 5 and 7 dpi with no significant differences in gene expression by 14dpi relative to uninjured WT nerve samples. Taken together, these data suggest that the gene expression profile in uninjured Cx32KO sciatic nerve strongly resembles that of a WT nerve following injury and that loss of Schwann cell Cx32 leads to a basal state of gene expression similar to that of an injured WT nerve. These findings support a role for Cx32 in non-myelinating and regenerating populations of Schwann cells in normal axonal maintenance in re-myelination, and regeneration of peripheral nerve following injury. Disruption of Schwann cell-axonal communication in CMT1X may cause dysregulation of signaling pathways that are essential for the maintenance of intact myelinated peripheral nerves and to establish the necessary conditions for successful regeneration and remyelination following nerve injury.
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Affiliation(s)
- Mona Freidin
- Department of Neuroscience, Albert Einstein College of Medicine, Bronx, NY 10461, USA.
| | - Samantha Asche-Godin
- Department of Neurology, State University of New York, Downstate Medical Center, Brooklyn, NY 11203, USA
| | - Charles K Abrams
- Department of Neurology, State University of New York, Downstate Medical Center, Brooklyn, NY 11203, USA
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Dexmedetomidine protects against apoptosis induced by hypoxia/reoxygenation through the inhibition of gap junctions in NRK-52E cells. Life Sci 2014; 122:72-7. [PMID: 25529146 DOI: 10.1016/j.lfs.2014.12.009] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2014] [Revised: 11/29/2014] [Accepted: 12/08/2014] [Indexed: 11/23/2022]
Abstract
AIMS The α2-adrenoceptor inducer dexmedetomidine (Dex) provides renoprotection against ischemia/reperfusion (I/R) injury, but the mechanism of this effect is largely unknown. The present study investigated the effect of Dex on apoptosis induced by hypoxia/reoxygenation (H/R) and the relationship between this effect and gap junction intercellular communication (GJIC). MAIN METHODS In vitro, two cell lines of normal rat kidney proximal tubular cells (NRK-52E) and HeLa cells that were transfected with a connexin 32 (Cx32) plasmid were exposed to H/R. The role of Dex in the modulation of H/R-induced apoptosis was explored by the manipulation of connexin expression, and hence gap junction (GJ) function, using a GJIC inhibitor, heptanol, and a GJIC inducer, retinoic acid. GJ function and the Cx32 protein level were determined by the parachute dye-coupling assay and Western blotting, respectively. KEY FINDINGS Dex and heptanol significantly reduced H/R-induced apoptosis in NRK-52E cells. The anti-apoptosis effect of Dex was exhibited only in Cx32-expressing HeLa cells. One hour Dex exposure inhibited GJ function mainly via a decrease in Cx32 protein levels in NRK-52E cells. SIGNIFICANCE Our data suggest that Dex reduced H/R-induced apoptosis through the inhibition of GJ activity by reducing Cx32 protein levels.
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24
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Artesi M, Kroonen J, Bredel M, Nguyen-Khac M, Deprez M, Schoysman L, Poulet C, Chakravarti A, Kim H, Scholtens D, Seute T, Rogister B, Bours V, Robe PA. Connexin 30 expression inhibits growth of human malignant gliomas but protects them against radiation therapy. Neuro Oncol 2014; 17:392-406. [PMID: 25155356 DOI: 10.1093/neuonc/nou215] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2013] [Accepted: 07/28/2014] [Indexed: 12/24/2022] Open
Abstract
BACKGROUND Glioblastomas remain ominous tumors that almost invariably escape treatment. Connexins are a family of transmembrane, gap junction-forming proteins, some members of which were reported to act as tumor suppressors and to modulate cellular metabolism in response to cytotoxic stress. METHODS We analyzed the copy number and expression of the connexin (Cx)30 gene gap junction beta-6 (GJB6), as well as of its protein immunoreactivity in several public and proprietary repositories of glioblastomas, and their influence on patient survival. We evaluated the effect of the expression of this gap junction protein on the growth, DNA repair and energy metabolism, and treatment resistance of these tumors. RESULTS The GJB6 gene was deleted in 25.8% of 751 analyzed tumors and mutated in 15.8% of 158 tumors. Cx30 immunoreactivity was absent in 28.9% of 145 tumors. Restoration of Cx30 expression in human glioblastoma cells reduced their growth in vitro and as xenografts in the striatum of immunodeficient mice. Cx30 immunoreactivity was, however, found to adversely affect survival in 2 independent retrospective cohorts of glioblastoma patients. Cx30 was found in clonogenic assays to protect glioblastoma cells against radiation-induced mortality and to decrease radiation-induced DNA damage. This radioprotection correlated with a heat shock protein 90-dependent mitochondrial translocation of Cx30 following radiation and an improved ATP production following this genotoxic stress. CONCLUSION These results underline the complex relationship between potential tumor suppressors and treatment resistance in glioblastomas and single out GJB6/Cx30 as a potential biomarker and target for therapeutic intervention in these tumors.
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Affiliation(s)
- Maria Artesi
- Department of Human Genetics, CBIG/GIGA Research Center, University of Liège, Liège, Belgium (M.A., J.K., M.N.-K., L.S., C.P., V.B., P.A.R.); Department of Neurology and Neurosurgery and T. and P. Bonhenn Neuro-Oncology Laboratory, University Hospital of Utrecht, Utrecht, Netherlands (J.K., L.S., T.S., P.A.R.); Robert H. Lurie Comprehensive Cancer Center, Feinberg School of Medicine, Chicago, Illinois (D.S.); Center for Population Health Sciences, Institute for Public Health and Medicine, Northwestern University, Chicago (D.S.); Division of Neuropathology, University Hospital of Liège, Liège, Belgium (M.D.); Division of Neurobiology, CBIG/GIGA Research Center, University Hospital of Liège, Liège, Belgium (B.R.); Department of Radiation Oncology, Arthur G James Comprehensive Cancer Center and Richard L. Solove Research Institute, The Ohio State University Medical Center, Columbus, Ohio (A.C., P.A.R.); Department of Radiation Oncology, Hazelrig-Salter Radiation Oncology Center and UAB Comprehensive Cancer Center, Birmingham, Alabama (M.B., H.K.)
| | - Jerome Kroonen
- Department of Human Genetics, CBIG/GIGA Research Center, University of Liège, Liège, Belgium (M.A., J.K., M.N.-K., L.S., C.P., V.B., P.A.R.); Department of Neurology and Neurosurgery and T. and P. Bonhenn Neuro-Oncology Laboratory, University Hospital of Utrecht, Utrecht, Netherlands (J.K., L.S., T.S., P.A.R.); Robert H. Lurie Comprehensive Cancer Center, Feinberg School of Medicine, Chicago, Illinois (D.S.); Center for Population Health Sciences, Institute for Public Health and Medicine, Northwestern University, Chicago (D.S.); Division of Neuropathology, University Hospital of Liège, Liège, Belgium (M.D.); Division of Neurobiology, CBIG/GIGA Research Center, University Hospital of Liège, Liège, Belgium (B.R.); Department of Radiation Oncology, Arthur G James Comprehensive Cancer Center and Richard L. Solove Research Institute, The Ohio State University Medical Center, Columbus, Ohio (A.C., P.A.R.); Department of Radiation Oncology, Hazelrig-Salter Radiation Oncology Center and UAB Comprehensive Cancer Center, Birmingham, Alabama (M.B., H.K.)
| | - Markus Bredel
- Department of Human Genetics, CBIG/GIGA Research Center, University of Liège, Liège, Belgium (M.A., J.K., M.N.-K., L.S., C.P., V.B., P.A.R.); Department of Neurology and Neurosurgery and T. and P. Bonhenn Neuro-Oncology Laboratory, University Hospital of Utrecht, Utrecht, Netherlands (J.K., L.S., T.S., P.A.R.); Robert H. Lurie Comprehensive Cancer Center, Feinberg School of Medicine, Chicago, Illinois (D.S.); Center for Population Health Sciences, Institute for Public Health and Medicine, Northwestern University, Chicago (D.S.); Division of Neuropathology, University Hospital of Liège, Liège, Belgium (M.D.); Division of Neurobiology, CBIG/GIGA Research Center, University Hospital of Liège, Liège, Belgium (B.R.); Department of Radiation Oncology, Arthur G James Comprehensive Cancer Center and Richard L. Solove Research Institute, The Ohio State University Medical Center, Columbus, Ohio (A.C., P.A.R.); Department of Radiation Oncology, Hazelrig-Salter Radiation Oncology Center and UAB Comprehensive Cancer Center, Birmingham, Alabama (M.B., H.K.)
| | - Minh Nguyen-Khac
- Department of Human Genetics, CBIG/GIGA Research Center, University of Liège, Liège, Belgium (M.A., J.K., M.N.-K., L.S., C.P., V.B., P.A.R.); Department of Neurology and Neurosurgery and T. and P. Bonhenn Neuro-Oncology Laboratory, University Hospital of Utrecht, Utrecht, Netherlands (J.K., L.S., T.S., P.A.R.); Robert H. Lurie Comprehensive Cancer Center, Feinberg School of Medicine, Chicago, Illinois (D.S.); Center for Population Health Sciences, Institute for Public Health and Medicine, Northwestern University, Chicago (D.S.); Division of Neuropathology, University Hospital of Liège, Liège, Belgium (M.D.); Division of Neurobiology, CBIG/GIGA Research Center, University Hospital of Liège, Liège, Belgium (B.R.); Department of Radiation Oncology, Arthur G James Comprehensive Cancer Center and Richard L. Solove Research Institute, The Ohio State University Medical Center, Columbus, Ohio (A.C., P.A.R.); Department of Radiation Oncology, Hazelrig-Salter Radiation Oncology Center and UAB Comprehensive Cancer Center, Birmingham, Alabama (M.B., H.K.)
| | - Manuel Deprez
- Department of Human Genetics, CBIG/GIGA Research Center, University of Liège, Liège, Belgium (M.A., J.K., M.N.-K., L.S., C.P., V.B., P.A.R.); Department of Neurology and Neurosurgery and T. and P. Bonhenn Neuro-Oncology Laboratory, University Hospital of Utrecht, Utrecht, Netherlands (J.K., L.S., T.S., P.A.R.); Robert H. Lurie Comprehensive Cancer Center, Feinberg School of Medicine, Chicago, Illinois (D.S.); Center for Population Health Sciences, Institute for Public Health and Medicine, Northwestern University, Chicago (D.S.); Division of Neuropathology, University Hospital of Liège, Liège, Belgium (M.D.); Division of Neurobiology, CBIG/GIGA Research Center, University Hospital of Liège, Liège, Belgium (B.R.); Department of Radiation Oncology, Arthur G James Comprehensive Cancer Center and Richard L. Solove Research Institute, The Ohio State University Medical Center, Columbus, Ohio (A.C., P.A.R.); Department of Radiation Oncology, Hazelrig-Salter Radiation Oncology Center and UAB Comprehensive Cancer Center, Birmingham, Alabama (M.B., H.K.)
| | - Laurent Schoysman
- Department of Human Genetics, CBIG/GIGA Research Center, University of Liège, Liège, Belgium (M.A., J.K., M.N.-K., L.S., C.P., V.B., P.A.R.); Department of Neurology and Neurosurgery and T. and P. Bonhenn Neuro-Oncology Laboratory, University Hospital of Utrecht, Utrecht, Netherlands (J.K., L.S., T.S., P.A.R.); Robert H. Lurie Comprehensive Cancer Center, Feinberg School of Medicine, Chicago, Illinois (D.S.); Center for Population Health Sciences, Institute for Public Health and Medicine, Northwestern University, Chicago (D.S.); Division of Neuropathology, University Hospital of Liège, Liège, Belgium (M.D.); Division of Neurobiology, CBIG/GIGA Research Center, University Hospital of Liège, Liège, Belgium (B.R.); Department of Radiation Oncology, Arthur G James Comprehensive Cancer Center and Richard L. Solove Research Institute, The Ohio State University Medical Center, Columbus, Ohio (A.C., P.A.R.); Department of Radiation Oncology, Hazelrig-Salter Radiation Oncology Center and UAB Comprehensive Cancer Center, Birmingham, Alabama (M.B., H.K.)
| | - Christophe Poulet
- Department of Human Genetics, CBIG/GIGA Research Center, University of Liège, Liège, Belgium (M.A., J.K., M.N.-K., L.S., C.P., V.B., P.A.R.); Department of Neurology and Neurosurgery and T. and P. Bonhenn Neuro-Oncology Laboratory, University Hospital of Utrecht, Utrecht, Netherlands (J.K., L.S., T.S., P.A.R.); Robert H. Lurie Comprehensive Cancer Center, Feinberg School of Medicine, Chicago, Illinois (D.S.); Center for Population Health Sciences, Institute for Public Health and Medicine, Northwestern University, Chicago (D.S.); Division of Neuropathology, University Hospital of Liège, Liège, Belgium (M.D.); Division of Neurobiology, CBIG/GIGA Research Center, University Hospital of Liège, Liège, Belgium (B.R.); Department of Radiation Oncology, Arthur G James Comprehensive Cancer Center and Richard L. Solove Research Institute, The Ohio State University Medical Center, Columbus, Ohio (A.C., P.A.R.); Department of Radiation Oncology, Hazelrig-Salter Radiation Oncology Center and UAB Comprehensive Cancer Center, Birmingham, Alabama (M.B., H.K.)
| | - Arnab Chakravarti
- Department of Human Genetics, CBIG/GIGA Research Center, University of Liège, Liège, Belgium (M.A., J.K., M.N.-K., L.S., C.P., V.B., P.A.R.); Department of Neurology and Neurosurgery and T. and P. Bonhenn Neuro-Oncology Laboratory, University Hospital of Utrecht, Utrecht, Netherlands (J.K., L.S., T.S., P.A.R.); Robert H. Lurie Comprehensive Cancer Center, Feinberg School of Medicine, Chicago, Illinois (D.S.); Center for Population Health Sciences, Institute for Public Health and Medicine, Northwestern University, Chicago (D.S.); Division of Neuropathology, University Hospital of Liège, Liège, Belgium (M.D.); Division of Neurobiology, CBIG/GIGA Research Center, University Hospital of Liège, Liège, Belgium (B.R.); Department of Radiation Oncology, Arthur G James Comprehensive Cancer Center and Richard L. Solove Research Institute, The Ohio State University Medical Center, Columbus, Ohio (A.C., P.A.R.); Department of Radiation Oncology, Hazelrig-Salter Radiation Oncology Center and UAB Comprehensive Cancer Center, Birmingham, Alabama (M.B., H.K.)
| | - Hyunsoo Kim
- Department of Human Genetics, CBIG/GIGA Research Center, University of Liège, Liège, Belgium (M.A., J.K., M.N.-K., L.S., C.P., V.B., P.A.R.); Department of Neurology and Neurosurgery and T. and P. Bonhenn Neuro-Oncology Laboratory, University Hospital of Utrecht, Utrecht, Netherlands (J.K., L.S., T.S., P.A.R.); Robert H. Lurie Comprehensive Cancer Center, Feinberg School of Medicine, Chicago, Illinois (D.S.); Center for Population Health Sciences, Institute for Public Health and Medicine, Northwestern University, Chicago (D.S.); Division of Neuropathology, University Hospital of Liège, Liège, Belgium (M.D.); Division of Neurobiology, CBIG/GIGA Research Center, University Hospital of Liège, Liège, Belgium (B.R.); Department of Radiation Oncology, Arthur G James Comprehensive Cancer Center and Richard L. Solove Research Institute, The Ohio State University Medical Center, Columbus, Ohio (A.C., P.A.R.); Department of Radiation Oncology, Hazelrig-Salter Radiation Oncology Center and UAB Comprehensive Cancer Center, Birmingham, Alabama (M.B., H.K.)
| | - Denise Scholtens
- Department of Human Genetics, CBIG/GIGA Research Center, University of Liège, Liège, Belgium (M.A., J.K., M.N.-K., L.S., C.P., V.B., P.A.R.); Department of Neurology and Neurosurgery and T. and P. Bonhenn Neuro-Oncology Laboratory, University Hospital of Utrecht, Utrecht, Netherlands (J.K., L.S., T.S., P.A.R.); Robert H. Lurie Comprehensive Cancer Center, Feinberg School of Medicine, Chicago, Illinois (D.S.); Center for Population Health Sciences, Institute for Public Health and Medicine, Northwestern University, Chicago (D.S.); Division of Neuropathology, University Hospital of Liège, Liège, Belgium (M.D.); Division of Neurobiology, CBIG/GIGA Research Center, University Hospital of Liège, Liège, Belgium (B.R.); Department of Radiation Oncology, Arthur G James Comprehensive Cancer Center and Richard L. Solove Research Institute, The Ohio State University Medical Center, Columbus, Ohio (A.C., P.A.R.); Department of Radiation Oncology, Hazelrig-Salter Radiation Oncology Center and UAB Comprehensive Cancer Center, Birmingham, Alabama (M.B., H.K.)
| | - Tatjana Seute
- Department of Human Genetics, CBIG/GIGA Research Center, University of Liège, Liège, Belgium (M.A., J.K., M.N.-K., L.S., C.P., V.B., P.A.R.); Department of Neurology and Neurosurgery and T. and P. Bonhenn Neuro-Oncology Laboratory, University Hospital of Utrecht, Utrecht, Netherlands (J.K., L.S., T.S., P.A.R.); Robert H. Lurie Comprehensive Cancer Center, Feinberg School of Medicine, Chicago, Illinois (D.S.); Center for Population Health Sciences, Institute for Public Health and Medicine, Northwestern University, Chicago (D.S.); Division of Neuropathology, University Hospital of Liège, Liège, Belgium (M.D.); Division of Neurobiology, CBIG/GIGA Research Center, University Hospital of Liège, Liège, Belgium (B.R.); Department of Radiation Oncology, Arthur G James Comprehensive Cancer Center and Richard L. Solove Research Institute, The Ohio State University Medical Center, Columbus, Ohio (A.C., P.A.R.); Department of Radiation Oncology, Hazelrig-Salter Radiation Oncology Center and UAB Comprehensive Cancer Center, Birmingham, Alabama (M.B., H.K.)
| | - Bernard Rogister
- Department of Human Genetics, CBIG/GIGA Research Center, University of Liège, Liège, Belgium (M.A., J.K., M.N.-K., L.S., C.P., V.B., P.A.R.); Department of Neurology and Neurosurgery and T. and P. Bonhenn Neuro-Oncology Laboratory, University Hospital of Utrecht, Utrecht, Netherlands (J.K., L.S., T.S., P.A.R.); Robert H. Lurie Comprehensive Cancer Center, Feinberg School of Medicine, Chicago, Illinois (D.S.); Center for Population Health Sciences, Institute for Public Health and Medicine, Northwestern University, Chicago (D.S.); Division of Neuropathology, University Hospital of Liège, Liège, Belgium (M.D.); Division of Neurobiology, CBIG/GIGA Research Center, University Hospital of Liège, Liège, Belgium (B.R.); Department of Radiation Oncology, Arthur G James Comprehensive Cancer Center and Richard L. Solove Research Institute, The Ohio State University Medical Center, Columbus, Ohio (A.C., P.A.R.); Department of Radiation Oncology, Hazelrig-Salter Radiation Oncology Center and UAB Comprehensive Cancer Center, Birmingham, Alabama (M.B., H.K.)
| | - Vincent Bours
- Department of Human Genetics, CBIG/GIGA Research Center, University of Liège, Liège, Belgium (M.A., J.K., M.N.-K., L.S., C.P., V.B., P.A.R.); Department of Neurology and Neurosurgery and T. and P. Bonhenn Neuro-Oncology Laboratory, University Hospital of Utrecht, Utrecht, Netherlands (J.K., L.S., T.S., P.A.R.); Robert H. Lurie Comprehensive Cancer Center, Feinberg School of Medicine, Chicago, Illinois (D.S.); Center for Population Health Sciences, Institute for Public Health and Medicine, Northwestern University, Chicago (D.S.); Division of Neuropathology, University Hospital of Liège, Liège, Belgium (M.D.); Division of Neurobiology, CBIG/GIGA Research Center, University Hospital of Liège, Liège, Belgium (B.R.); Department of Radiation Oncology, Arthur G James Comprehensive Cancer Center and Richard L. Solove Research Institute, The Ohio State University Medical Center, Columbus, Ohio (A.C., P.A.R.); Department of Radiation Oncology, Hazelrig-Salter Radiation Oncology Center and UAB Comprehensive Cancer Center, Birmingham, Alabama (M.B., H.K.)
| | - Pierre A Robe
- Department of Human Genetics, CBIG/GIGA Research Center, University of Liège, Liège, Belgium (M.A., J.K., M.N.-K., L.S., C.P., V.B., P.A.R.); Department of Neurology and Neurosurgery and T. and P. Bonhenn Neuro-Oncology Laboratory, University Hospital of Utrecht, Utrecht, Netherlands (J.K., L.S., T.S., P.A.R.); Robert H. Lurie Comprehensive Cancer Center, Feinberg School of Medicine, Chicago, Illinois (D.S.); Center for Population Health Sciences, Institute for Public Health and Medicine, Northwestern University, Chicago (D.S.); Division of Neuropathology, University Hospital of Liège, Liège, Belgium (M.D.); Division of Neurobiology, CBIG/GIGA Research Center, University Hospital of Liège, Liège, Belgium (B.R.); Department of Radiation Oncology, Arthur G James Comprehensive Cancer Center and Richard L. Solove Research Institute, The Ohio State University Medical Center, Columbus, Ohio (A.C., P.A.R.); Department of Radiation Oncology, Hazelrig-Salter Radiation Oncology Center and UAB Comprehensive Cancer Center, Birmingham, Alabama (M.B., H.K.)
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Le Bourhis M, Rimbaud S, Grebert D, Congar P, Meunier N. Endothelin uncouples gap junctions in sustentacular cells and olfactory ensheathing cells of the olfactory mucosa. Eur J Neurosci 2014; 40:2878-87. [PMID: 24995882 DOI: 10.1111/ejn.12665] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2014] [Revised: 05/28/2014] [Accepted: 06/02/2014] [Indexed: 11/30/2022]
Abstract
Several factors modulate the first step of odour detection in the rat olfactory mucosa (OM). Among others, vasoactive peptides such as endothelin might play multifaceted roles in the different OM cells. Like their counterparts in the central nervous system, the olfactory sensory neurons are encompassed by different glial-like non-neuronal OM cells; sustentacular cells (SCs) surround their cell bodies, whereas olfactory ensheathing cells (OECs) wrap their axons. Whereas SCs maintain both the structural and ionic integrity of the OM, OECs assure protection, local blood flow control and guiding of olfactory sensory neuron axons toward the olfactory bulb. We previously showed that these non-neuronal OM cells are particularly responsive to endothelin in vitro. Here, we confirmed that the endothelin system is strongly expressed in the OM using in situ hybridization. We then further explored the effects of endothelin on SCs and OECs using electrophysiological recordings and calcium imaging approaches on both in vitro and ex vivo OM preparations. Endothelin induced both robust calcium signals and gap junction uncoupling in both types of cells. This latter effect was mimicked by carbenoxolone, a known gap junction uncoupling agent. However, although endothelin is known for its antiapoptotic effect in the OM, the uncoupling of gap junctions by carbenoxolone was not sufficient to limit the cellular death induced by serum deprivation in OM primary culture. The functional consequence of the endothelin 1-induced reduction of the gap junctional communication between OM non-neuronal cells thus remains to be elucidated.
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Affiliation(s)
- Mikaël Le Bourhis
- Université d'Evry Val d'Essone, Evry, France; Domaine de Vilvert, INRA, UR1197 Neurobiologie de l'Olfaction et Modélisation en Imagerie, Biologie de l'Olfaction et Biosenseurs, Jouy en Josas, France; Neuro-Sud, IFR 144, Paris, France
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Carette D, Gilleron J, Chevallier D, Segretain D, Pointis G. Connexin a check-point component of cell apoptosis in normal and physiopathological conditions. Biochimie 2014; 101:1-9. [DOI: 10.1016/j.biochi.2013.11.015] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2013] [Accepted: 11/18/2013] [Indexed: 12/16/2022]
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Moinfar Z, Dambach H, Faustmann PM. Influence of drugs on gap junctions in glioma cell lines and primary astrocytes in vitro. Front Physiol 2014; 5:186. [PMID: 24904426 PMCID: PMC4032976 DOI: 10.3389/fphys.2014.00186] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2013] [Accepted: 04/25/2014] [Indexed: 12/17/2022] Open
Abstract
Gap junctions (GJs) are hemichannels on cell membrane. Once they are intercellulary connected to the neighboring cells, they build a functional syncytium which allows rapid transfer of ions and molecules between cells. This characteristic makes GJs a potential modulator in proliferation, migration, and development of the cells. So far, several types of GJs are recognized on different brain cells as well as in glioma. Astrocytes, as one of the major cells that maintain neuronal homeostasis, express different types of GJs that let them communicate with neurons, oligodendrocytes, and endothelial cells of the blood brain barrier; however, the main GJ in astrocytes is connexin 43. There are different cerebral diseases in which astrocyte GJs might play a role. Several drugs have been reported to modulate gap junctional communication in the brain which can consequently have beneficial or detrimental effects on the course of treatment in certain diseases. However, the exact cellular mechanism behind those pharmaceutical efficacies on GJs is not well-understood. Accordingly, how specific drugs would affect GJs and what some consequent specific brain diseases would be are the interests of the authors of this chapter. We would focus on pharmaceutical effects on GJs on astrocytes in specific diseases where GJs could possibly play a role including: (1) migraine and a novel therapy for migraine with aura, (2) neuroautoimmune diseases and immunomodulatory drugs in the treatment of demyelinating diseases of the central nervous system such as multiple sclerosis, (3) glioma and antineoplastic and anti-inflammatory agents that are used in treating brain tumors, and (4) epilepsy and anticonvulsants that are widely used for seizures therapy. All of the above-mentioned therapeutic categories can possibly affect GJs expression of astrocytes and the role is discussed in the upcoming chapter.
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Affiliation(s)
- Zahra Moinfar
- International Graduate School of Neuroscience, Ruhr University Bochum Bochum, Germany ; Department of Neuroanatomy and Molecular Brain Research, Ruhr University Bochum Bochum, Germany
| | - Hannes Dambach
- Department of Neuroanatomy and Molecular Brain Research, Ruhr University Bochum Bochum, Germany
| | - Pedro M Faustmann
- International Graduate School of Neuroscience, Ruhr University Bochum Bochum, Germany ; Department of Neuroanatomy and Molecular Brain Research, Ruhr University Bochum Bochum, Germany
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Reyes EP, Cerpa V, Corvalán L, Retamal MA. Cxs and Panx- hemichannels in peripheral and central chemosensing in mammals. Front Cell Neurosci 2014; 8:123. [PMID: 24847209 PMCID: PMC4023181 DOI: 10.3389/fncel.2014.00123] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2014] [Accepted: 04/18/2014] [Indexed: 01/08/2023] Open
Abstract
Connexins (Cxs) and Pannexins (Panx) form hemichannels at the plasma membrane of animals. Despite their low open probability under physiological conditions, these hemichannels release signaling molecules (i.e., ATP, Glutamate, PGE2) to the extracellular space, thus subserving several important physiological processes. Oxygen and CO2 sensing are fundamental to the normal functioning of vertebrate organisms. Fluctuations in blood PO2, PCO2 and pH are sensed at the carotid bifurcations of adult mammals by glomus cells of the carotid bodies. Likewise, changes in pH and/or PCO2 of cerebrospinal fluid are sensed by central chemoreceptors, a group of specialized neurones distributed in the ventrolateral medulla (VLM), raphe nuclei, and some other brainstem areas. After many years of research, the molecular mechanisms involved in chemosensing process are not completely understood. This manuscript will review data regarding relationships between chemosensitive cells and the expression of channels formed by Cxs and Panx, with special emphasis on hemichannels.
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Affiliation(s)
- Edison Pablo Reyes
- Centro de Fisiología Celular e Integrativa, Facultad de Medicina, Clínica Alemana Universidad del Desarrollo Santiago, Chile ; Dirección de Investigación, Universidad Autónoma de Chile Santiago, Chile
| | - Verónica Cerpa
- Centro de Fisiología Celular e Integrativa, Facultad de Medicina, Clínica Alemana Universidad del Desarrollo Santiago, Chile
| | - Liliana Corvalán
- Centro de Fisiología Celular e Integrativa, Facultad de Medicina, Clínica Alemana Universidad del Desarrollo Santiago, Chile
| | - Mauricio Antonio Retamal
- Centro de Fisiología Celular e Integrativa, Facultad de Medicina, Clínica Alemana Universidad del Desarrollo Santiago, Chile
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Igarashi I, Maejima T, Kai K, Arakawa S, Teranishi M, Sanbuissho A. Role of connexin 32 in acetaminophen toxicity in a knockout mice model. EXPERIMENTAL AND TOXICOLOGIC PATHOLOGY : OFFICIAL JOURNAL OF THE GESELLSCHAFT FUR TOXIKOLOGISCHE PATHOLOGIE 2014; 66:103-10. [PMID: 24263089 DOI: 10.1016/j.etp.2013.10.002] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2013] [Revised: 09/03/2013] [Accepted: 10/21/2013] [Indexed: 01/28/2023]
Abstract
Gap junctional intercellular communication (GJIC), by which glutathione (GSH) and inorganic ions are transmitted to neighboring cells, is recognized as being largely involved in toxic processes of chemicals. We examined acetaminophen (APAP)-induced hepatotoxicity clinicopathologically using male wild-type mice and mice lacking the gene for connexin32, a major gap junction protein in the liver [knockout (Cx32KO) mice]. When APAP was intraperitoneally administered at doses of 100, 200, or 300mg/kg, hepatic centrilobular necrosis with elevated plasma aminotransferase activities was observed in wild-type mice receiving 300mg/kg, and in Cx32KO mice given 100mg/kg or more. At 200mg/kg or more, hepatic GSH and GSSG contents decreased significantly and the effect was more severe in wild-type mice than in Cx32KO mice. On the other hand, markedly decreased GSH staining was observed in the hepatic centrilobular zones of Cx32KO mice compared to that of wild-type mice. These results demonstrate that Cx32KO mice are more susceptible to APAP hepatotoxicity than wild-type mice, and indicate that the distribution of GSH of the centrilobular zones in the hepatic lobules, rather than GSH and GSSG contents in the liver, is important in APAP hepatotoxicity. In conclusion, Cx32 protects against APAP-induced hepatic centrilobular necrosis in mice, which may be through the GSH transmission to neighboring hepatocytes by GJIC.
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Affiliation(s)
- Isao Igarashi
- Medicinal Safety Research Laboratories, Daiichi Sankyo Co. Ltd., Fukuroi, Shizuoka 437-0065, Japan.
| | - Takanori Maejima
- Medicinal Safety Research Laboratories, Daiichi Sankyo Co. Ltd., Fukuroi, Shizuoka 437-0065, Japan
| | - Kiyonori Kai
- Medicinal Safety Research Laboratories, Daiichi Sankyo Co. Ltd., Fukuroi, Shizuoka 437-0065, Japan
| | - Shingo Arakawa
- Medicinal Safety Research Laboratories, Daiichi Sankyo Co. Ltd., Fukuroi, Shizuoka 437-0065, Japan
| | - Munehiro Teranishi
- Medicinal Safety Research Laboratories, Daiichi Sankyo Co. Ltd., Fukuroi, Shizuoka 437-0065, Japan
| | - Atsushi Sanbuissho
- Medicinal Safety Research Laboratories, Daiichi Sankyo Co. Ltd., Fukuroi, Shizuoka 437-0065, Japan
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Ganesan S, Keating AF. Impact of 7,12-dimethylbenz[a]anthracene exposure on connexin gap junction proteins in cultured rat ovaries. Toxicol Appl Pharmacol 2014; 274:209-14. [PMID: 24269759 PMCID: PMC3932824 DOI: 10.1016/j.taap.2013.11.008] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2013] [Revised: 11/11/2013] [Accepted: 11/12/2013] [Indexed: 10/26/2022]
Abstract
7,12-Dimethylbenz[a]anthracene (DMBA) destroys ovarian follicles in a concentration-dependent manner. The impact of DMBA on connexin (CX) proteins that mediate communication between follicular cell types along with pro-apoptotic factors p53 and Bax were investigated. Postnatal day (PND) 4 Fisher 344 rat ovaries were cultured for 4days in vehicle medium (1% DMSO) followed by a single exposure to vehicle control (1% DMSO) or DMBA (12.5nM or 75nM) and cultured for 4 or 8days. RT-PCR was performed to quantify Cx37, Cx43, p53 and Bax mRNA level. Western blotting and immunofluorescence staining were performed to determine CX37 or CX43 level and/or localization. Cx37 mRNA and protein increased (P<0.05) at 4days of 12.5 nM DMBA exposure. Relative to vehicle control-treated ovaries, mRNA encoding Cx43 decreased (P<0.05) but CX43 protein increased (P<0.05) at 4days by both DMBA exposures. mRNA expression of pro-apoptotic p53 was decreased (P<0.05) but no changes in Bax expression were observed after 4days of DMBA exposures. In contrast, after 8days, DMBA decreased Cx37 and Cx43 mRNA and protein but increased both p53 and Bax mRNA levels. CX43 protein was located between granulosa cells, while CX37 was located at the oocyte cell surface of all follicle stages. These findings support that DMBA exposure impacts ovarian Cx37 and Cx43 mRNA and protein prior to both observed changes in pro-apoptotic p53 and Bax and follicle loss. It is possible that such interference in follicular cell communication is detrimental to follicle viability, and may play a role in DMBA-induced follicular atresia.
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Affiliation(s)
- Shanthi Ganesan
- Department of Animal Science, Iowa State University, Ames, IA 50011, USA.
| | - Aileen F Keating
- Department of Animal Science, Iowa State University, Ames, IA 50011, USA.
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Gielen PR, Aftab Q, Ma N, Chen VC, Hong X, Lozinsky S, Naus CC, Sin WC. Connexin43 confers Temozolomide resistance in human glioma cells by modulating the mitochondrial apoptosis pathway. Neuropharmacology 2013; 75:539-48. [PMID: 23688923 DOI: 10.1016/j.neuropharm.2013.05.002] [Citation(s) in RCA: 84] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2013] [Revised: 04/26/2013] [Accepted: 05/01/2013] [Indexed: 10/26/2022]
Abstract
Glioblastoma multiforme (GBM) is the most aggressive astrocytoma, and therapeutic options are generally limited to surgical resection, radiotherapy, and Temozolomide (TMZ) chemotherapy. TMZ is a DNA alkylating agent that causes DNA damage and induces cell death. Unfortunately, glioma cells often develop resistance to TMZ treatment, with DNA de-methylation of the MGMT promoter identified as the primary reason. However, the contributions from proteins that normally protect cells against cytotoxic stress in TMZ-induced apoptosis have not been extensively explored. Here, we showed that increasing the level of the gap junction protein, Cx43, in human LN18 and LN229 glioma cells enhances resistance to TMZ treatment while knockdown of Cx43 in these same cells sensitizes them to TMZ treatment. By expressing a channel-dead or a C-terminal truncation mutant of Cx43, we show that Cx43-mediated TMZ resistance involves both channel dependent and independent functions. Expression of Cx43 in LN229 cells decreases TMZ-induced apoptosis, as determined by Annexin V staining. Cx43-mediated chemoresistance appears to be acting via a mitochondrial apoptosis pathway as manifested by the reduction in Bax/Bcl-2 ratio and the release of cytochrome C. Our findings highlight additional mechanisms and proteins that contribute to TMZ resistance, and raise the possibility of increasing TMZ efficiency by targeting Cx43 protein. This article is part of the Special Issue Section entitled 'Current Pharmacology of Gap Junction Channels and Hemichannels'.
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Affiliation(s)
- Paul R Gielen
- Department of Cellular and Physiological Science, Life Science Institute, University of British Columbia, 2350 Health Science Mall, Vancouver, BC V6T 1Z3, Canada; Department of Tumor Immunology, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, 6500 HB Nijmegen, Netherlands
| | - Qurratulain Aftab
- Department of Cellular and Physiological Science, Life Science Institute, University of British Columbia, 2350 Health Science Mall, Vancouver, BC V6T 1Z3, Canada
| | - Noreen Ma
- Department of Cellular and Physiological Science, Life Science Institute, University of British Columbia, 2350 Health Science Mall, Vancouver, BC V6T 1Z3, Canada
| | - Vincent C Chen
- Department of Cellular and Physiological Science, Life Science Institute, University of British Columbia, 2350 Health Science Mall, Vancouver, BC V6T 1Z3, Canada
| | - Xiaoting Hong
- Department of Cellular and Physiological Science, Life Science Institute, University of British Columbia, 2350 Health Science Mall, Vancouver, BC V6T 1Z3, Canada
| | - Shannon Lozinsky
- Department of Cellular and Physiological Science, Life Science Institute, University of British Columbia, 2350 Health Science Mall, Vancouver, BC V6T 1Z3, Canada
| | - Christian C Naus
- Department of Cellular and Physiological Science, Life Science Institute, University of British Columbia, 2350 Health Science Mall, Vancouver, BC V6T 1Z3, Canada
| | - Wun Chey Sin
- Department of Cellular and Physiological Science, Life Science Institute, University of British Columbia, 2350 Health Science Mall, Vancouver, BC V6T 1Z3, Canada.
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Protective effects of carbenoxolone are associated with attenuation of oxidative stress in ischemic brain injury. Neurosci Bull 2013; 29:311-20. [PMID: 23650049 DOI: 10.1007/s12264-013-1342-y] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2012] [Accepted: 10/02/2012] [Indexed: 12/19/2022] Open
Abstract
Accumulating evidence has suggested that the gap junction plays an important role in the determination of cerebral ischemia, but the underlying mechanisms remain to be elucidated. In this study, we assessed the effect of a gap-junction blocker, carbenoxolone (CBX), on ischemia/reperfusion-induced brain injury and the possible mechanisms. By using the transient cerebral ischemia model induced by occlusion of the middle cerebral artery for 30 min followed by reperfusion for 24 h, we found that pre-administration of CBX (25 mg/kg, intracerebroventricular injection, 30 min before cerebral ischemic surgery) diminished the infarction size in rats. And this was associated with a decrease of reactive oxygen species generation and inhibition of the activation of astrocytes and microglia. In PC12 cells, H2O2 treatment induced more coupling and apoptosis, while CBX partly inhibited the opening of gap junctions and improved the cell viability. These results suggest that cerebral ischemia enhances the opening of gap junctions. Blocking the gap junction with CBX may attenuate the brain injury after cerebral ischemia/reperfusion by partially contributing to amelioration of the oxidative stress and apoptosis.
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Yan Q, Gao K, Chi Y, Li K, Zhu Y, Wan Y, Sun W, Matsue H, Kitamura M, Yao J. NADPH oxidase-mediated upregulation of connexin43 contributes to podocyte injury. Free Radic Biol Med 2012; 53:1286-97. [PMID: 22824863 DOI: 10.1016/j.freeradbiomed.2012.07.012] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/09/2012] [Revised: 07/06/2012] [Accepted: 07/13/2012] [Indexed: 10/28/2022]
Abstract
The gap junction protein connexin43 (Cx43) was markedly increased in podocytes in a rat model of nephrosis induced by puromycin. However, the mechanisms and roles of the altered Cx43 in podocytes are still unclear. Given that oxidative stress mediates podocyte injury under a variety of pathological situations, we examined the possible involvement of an oxidative stress-related mechanism in the regulation of Cx43. Incubation of podocytes with puromycin led to a time- and concentration-dependent loss of cell viability, which was preceded by an elevation in Cx43 levels. Concomitantly, puromycin also induced NOX4 expression and promoted superoxide (O(2)(·-)) generation. Inhibition of NADPH oxidase with apocynin and diphenyleneiodonium chloride or addition of the superoxide dismutase mimetic tempol completely abrogated, whereas the O(2)(·-) donors menadione and 2,3-dimethoxy-1,4-naphthoquinone reproduced, the effects of puromycin on Cx43 expression and cell injury. Further analysis demonstrated that treatment of podocytes with several structurally different gap-junction inhibitors significantly attenuated the cytotoxicity of puromycin. Our results thus indicate that NADPH oxidase-mediated upregulation of Cx43 contributes to podocyte injury.
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Affiliation(s)
- Qiaojing Yan
- Department of Molecular Signaling, Interdisciplinary Graduate School of Medicine and Engineering, University of Yamanashi, Yamanashi 409-3898, Japan
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Abrams CK, Scherer SS. Gap junctions in inherited human disorders of the central nervous system. BIOCHIMICA ET BIOPHYSICA ACTA 2012; 1818:2030-47. [PMID: 21871435 PMCID: PMC3771870 DOI: 10.1016/j.bbamem.2011.08.015] [Citation(s) in RCA: 86] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2011] [Revised: 08/04/2011] [Accepted: 08/10/2011] [Indexed: 12/15/2022]
Abstract
CNS glia and neurons express connexins, the proteins that form gap junctions in vertebrates. We review the connexins expressed by oligodendrocytes and astrocytes, and discuss their proposed physiologic roles. Of the 21 members of the human connexin family, mutations in three are associated with significant central nervous system manifestations. For each, we review the phenotype and discuss possible mechanisms of disease. Mutations in GJB1, the gene for connexin 32 (Cx32) cause the second most common form of Charcot-Marie-Tooth disease (CMT1X). Though the only consistent phenotype in CMT1X patients is a peripheral demyelinating neuropathy, CNS signs and symptoms have been found in some patients. Recessive mutations in GJC2, the gene for Cx47, are one cause of Pelizaeus-Merzbacher-like disease (PMLD), which is characterized by nystagmus within the first 6 months of life, cerebellar ataxia by 4 years, and spasticity by 6 years of age. MRI imaging shows abnormal myelination. A different recessive GJC2 mutation causes a form of hereditary spastic paraparesis, which is a milder phenotype than PMLD. Dominant mutations in GJA1, the gene for Cx43, cause oculodentodigital dysplasia (ODDD), a pleitropic disorder characterized by oculo-facial abnormalities including micropthalmia, microcornia and hypoplastic nares, syndactyly of the fourth to fifth fingers and dental abnormalities. Neurologic manifestations, including spasticity and gait difficulties, are often but not universally seen. Recessive GJA1 mutations cause Hallermann-Streiff syndrome, a disorder showing substantial overlap with ODDD. This article is part of a Special Issue entitled: The Communicating junctions, composition, structure and functions.
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Affiliation(s)
- Charles K. Abrams
- Department of Neurology and Physiology & Pharmacology, SUNY Downstate Medical Center, 450 Clarkson Avenue, Brooklyn, NY 11203, 1-718-270-1270 Phone, 1-718-270-8944 Fax,
| | - Steven S. Scherer
- Department of Neurology, The University of Pennsylvania School of Medicine, Room 450 Stemmler Hall, 36th Street and Hamilton Walk, Philadelphia, PA 19104-6077, 215-573-3198,
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Opposing roles of connexin43 in glioma progression. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2012; 1818:2058-67. [DOI: 10.1016/j.bbamem.2011.10.022] [Citation(s) in RCA: 88] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2011] [Revised: 10/17/2011] [Accepted: 10/24/2011] [Indexed: 12/12/2022]
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Wasielewski B, Jensen A, Roth-Härer A, Dermietzel R, Meier C. Neuroglial activation and Cx43 expression are reduced upon transplantation of human umbilical cord blood cells after perinatal hypoxic-ischemic injury. Brain Res 2012; 1487:39-53. [PMID: 22796290 DOI: 10.1016/j.brainres.2012.05.066] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2012] [Accepted: 05/31/2012] [Indexed: 12/15/2022]
Abstract
Glial cells play a crucial role in the pathomechanism of perinatal hypoxic-ischemic brain injury (HI) and are involved in the maintenance of a chronic state of inflammation that causes delayed neuronal damage. Activation of astrocytes is one factor prolonging brain damage and contributing to the formation of a glial scar that limits neuronal plasticity. In this context, the major astrocytic gap junction protein Connexin 43 (Cx43) has been ascribed various functions including regulation of astrocytic migration and proliferation. Here, we investigate glial responses like microglia/macrophages and astrocytic activation in a rat model of neonatal HI and characterize changes of these parameters upon transplantation of human umbilical cord blood cells (hUCB). As an alleviation of motor function in lesioned rats has previously been described in transplanted animals, we analyze the putative correlation between motor function and glial activation over time. The lesion-induced impairment of motor function, assessed by forelimb use bias, muscle strength and distal spasticity, was alleviated upon transplantation of hUCB short and long term. HI induced an acute inflammatory reaction with activation of microglia/macrophages and reactive astrogliosis associated with perilesional upregulation of Cx43 that slowly declined during the chronic post-ischemic phase. hUCB transplantation accelerated the regression of inflammatory events, narrowed the perilesional astrocytic wall and led to a downregulation of the investigated astrocytic proteins. Thus, in the immature brain, hUCB may indirectly reduce secondary cell death upon hypoxia-ischemia and facilitate post-ischemic plasticity through the attenuation of reactive gliosis. This article is part of a Special Issue entitled Electrical Synapses.
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Affiliation(s)
- Bianca Wasielewski
- Department of Neuroanatomy and Molecular Brain Research, Ruhr-University Bochum, D-44801 Bochum, Germany
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Rosenberg M, Lutz M, Kühl C, Will R, Eckstein V, Krebs J, Katus HA, Frey N. Coculture with hematopoietic stem cells protects cardiomyocytes against apoptosis via paracrine activation of AKT. J Transl Med 2012; 10:115. [PMID: 22672705 PMCID: PMC3408384 DOI: 10.1186/1479-5876-10-115] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2011] [Accepted: 06/06/2012] [Indexed: 02/08/2023] Open
Abstract
Background Previous experimental studies concluded that stem cells (SC) may exert their beneficial effects on the ischemic heart by paracrine activation of antiapoptotic pathways. In order to identify potential cardioprotective mediators, we performed a systematic analysis of the differential gene expression of hematopoietic SC after coculture with cardiomyocytes (CM). Methods After 48 h of coculture with neonatal rat ventricular CM (NRVCM), two consecutive cell sorting steps generated a highly purified population of conditioned murine hematopoietic SC (>99%). Next, a genome-wide microarray analysis of cocultured vs. monocultured hematopoietic SC derived from three independent experiments was performed. The analysis of differentially expressed genes was focused on products that are secretable and/or membrane-bound and potentially involved in antiapoptotic signalling. Results We found CCL-12, Macrophage Inhibitory Factor, Fibronectin and connexin 40 significantly upregulated in our coculture model. An ELISA of cell culture supernatants was performed to confirm secretion of candidate genes and showed that coculture supernatants revealed markedly higher CCL-12 concentrations. Moreover, we stimulated NRVCM with concentrated coculture supernatants which resulted in a significant reduction of apoptosis compared to monoculture-derived supernatant. Mechanistically, NRVCMs stimulated with coculture supernatants showed a higher level of AKT-phosphorylation, consistent with enhanced antiapoptotic signaling. Conclusion In summary, our results show that the interaction between hematopoietic SC and NRVCM led to a modified gene expression and induction of antiapoptotic pathways. These findings may thus at least in part explain the cardioprotective effects of hematopoietic SC.
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Affiliation(s)
- Mark Rosenberg
- Department of Internal Medicine III (Cardiology and Angiology), University Medical Center Schleswig-Holstein, Campus Kiel, Schittenhelmstr, 12, D-24105, Kiel, Germany
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DU-145 prostate carcinoma cells that selectively transmigrate narrow obstacles express elevated levels of Cx43. Cell Mol Biol Lett 2011; 16:625-37. [PMID: 21910090 PMCID: PMC6275569 DOI: 10.2478/s11658-011-0027-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2011] [Accepted: 09/06/2011] [Indexed: 12/16/2022] Open
Abstract
The formation of aqueous intercellular channels mediating gap junctional intercellular coupling (GJIC) is a canonical function of connexins (Cx). In contrast, mechanisms of GJIC-independent involvement of connexins in cancer formation and metastasis remain a matter of debate. Because of the role of Cx43 in the determination of carcinoma cell invasive potential, we addressed the problem of the possible Cx43 involvement in early prostate cancer invasion. For this purpose, we analysed Cx43-positive DU-145 cell subsets established from the progenies of the cells most readily transmigrating microporous membranes. These progenies displayed motile activity similar to the control DU-145 cells but were characterized by elevated Cx43 expression levels and GJIC intensity. Thus, apparent links exist between Cx43 expression and transmigration potential of DU-145 cells. Moreover, Cx43 expression profiles in the analysed DU-145 subsets were not affected by intercellular contacts and chemical inhibition of GJIC during the transmigration. Our observations indicate that neither cell motility nor GJIC determines the transmigration efficiency of DU-145 cells. However, we postulate that selective transmigration of prostate cancer cells expressing elevated levels of Cx43 expression may be crucial for the "leading front" formation during cancer invasion.
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Avila MA, Sell SL, Hawkins BE, Hellmich HL, Boone DR, Crookshanks JM, Prough DS, DeWitt DS. Cerebrovascular connexin expression: effects of traumatic brain injury. J Neurotrauma 2011; 28:1803-11. [PMID: 21895483 PMCID: PMC3172862 DOI: 10.1089/neu.2011.1900] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Traumatic brain injury (TBI) results in dysfunction of the cerebrovasculature. Gap junctions coordinate vasomotor responses and evidence suggests that they are involved in cerebrovascular dysfunction after TBI. Gap junctions are comprised of connexin proteins (Cxs), of which Cx37, Cx40, Cx43, and Cx45 are expressed in vascular tissue. This study tests the hypothesis that TBI alters Cx mRNA and protein expression in cerebral vascular smooth muscle and endothelial cells. Anesthetized (1.5% isoflurane) male Sprague-Dawley rats received sham or fluid-percussion TBI. Two, 6, and 24 h after, cerebral arteries were harvested, fresh-frozen for RNA isolation, or homogenized for Western blot analysis. Cerebral vascular endothelial and smooth muscle cells were selected from frozen sections using laser capture microdissection. RNA was quantified by ribonuclease protection assay. The mRNA for all four Cx genes showed greater expression in the smooth muscle layer compared to the endothelial layer. Smooth muscle Cx43 mRNA expression was reduced 2 h and endothelial Cx45 mRNA expression was reduced 24 h after injury. Western blot analysis revealed that Cx40 protein expression increased, while Cx45 protein expression decreased 24 h after injury. These studies revealed significant changes in the mRNA and protein expression of specific vascular Cxs after TBI. This is the first demonstration of cell type-related differential expression of Cx mRNA in cerebral arteries, and is a first step in evaluating the effects of TBI on gap junction communication in the cerebrovasculature.
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Affiliation(s)
| | | | - Bridget E. Hawkins
- Charles Allen Laboratories, Department of Anesthesiology, University of Texas Medical Branch, Galveston, Texas
| | - Helen L. Hellmich
- Charles Allen Laboratories, Department of Anesthesiology, University of Texas Medical Branch, Galveston, Texas
| | - Debbie R. Boone
- Charles Allen Laboratories, Department of Anesthesiology, University of Texas Medical Branch, Galveston, Texas
| | - Jeanna M. Crookshanks
- Charles Allen Laboratories, Department of Anesthesiology, University of Texas Medical Branch, Galveston, Texas
| | - Donald S. Prough
- Charles Allen Laboratories, Department of Anesthesiology, University of Texas Medical Branch, Galveston, Texas
| | - Douglas S. DeWitt
- Charles Allen Laboratories, Department of Anesthesiology, University of Texas Medical Branch, Galveston, Texas
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Lee J, Yim YS, Ko SJ, Kim DG, Kim CH. Gap junctions contribute to astrocytic resistance against zinc toxicity. Brain Res Bull 2011; 86:314-8. [PMID: 21884763 DOI: 10.1016/j.brainresbull.2011.08.011] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2011] [Revised: 08/14/2011] [Accepted: 08/16/2011] [Indexed: 10/17/2022]
Abstract
Astrocytic gap junctions have been implicated in the regulation of cell viability. High amounts of extracellular zinc, which is released during ischemia, seizure, and brain trauma, can be cytotoxic to astrocytes. We tested whether gap junction coupling between astrocytes plays an important role in modulating zinc toxicity in hippocampal astrocytes. Zinc induces cell death in a dose-dependent manner in primary cultured hippocampal astrocytes. Two gap junction inhibitors, 18β-glycyrrhetinic acid and arachidonic acid, had no effect on zinc-induced cell death in low-confluence culture, where physical separation prevents gap junctions from forming. However, these inhibitors can potentiate zinc toxicity in high-confluence astrocyte cultures. Zinc toxicity was substantially suppressed upon connexin 43 overexpression, whereas knockdown caused a significant enhancement of the toxicity in high-confluence cultures. These data suggest that gap junctions in hippocampal astrocytes provide a protective role against zinc toxicity.
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Affiliation(s)
- Jinu Lee
- College of Pharmacy, Yonsei Institute of Pharmaceutical Sciences, Yonsei University, 162-1 Songdo-dong, Yeonsu-gu, Inchon 406-840, Republic of Korea.
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Abstract
Cx (connexin) proteins are components of gap junctions which are aqueous pores that allow intercellular exchange of ions and small molecules. Mutations in Cx genes are linked to a range of human disorders. In the present review we discuss mutations in β-Cx genes encoding Cx26, Cx30, Cx30.3 and Cx31 which lead to skin disease and deafness. Functional studies with Cx proteins have given insights into disease-associated mechanisms and non-gap junctional roles for Cx proteins.
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Rodríguez-Sinovas A, Sánchez JA, Fernandez-Sanz C, Ruiz-Meana M, Garcia-Dorado D. Connexin and pannexin as modulators of myocardial injury. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2011; 1818:1962-70. [PMID: 21839721 DOI: 10.1016/j.bbamem.2011.07.041] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2011] [Revised: 07/20/2011] [Accepted: 07/28/2011] [Indexed: 01/02/2023]
Abstract
Multicellular organisms have developed a variety of mechanisms that allow communication between their cells. Whereas some of these systems, as neurotransmission or hormones, make possible communication between remote areas, direct cell-to-cell communication through specific membrane channels keep in contact neighboring cells. Direct communication between the cytoplasm of adjacent cells is achieved in vertebrates by membrane channels formed by connexins. However, in addition to allowing exchange of ions and small metabolites between the cytoplasms of adjacent cells, connexin channels also communicate the cytosol with the extracellular space, thus enabling a completely different communication system, involving activation of extracellular receptors. Recently, the demonstration of connexin at the inner mitochondrial membrane of cardiomyocytes, probably forming hemichannels, has enlarged the list of actions of connexins. Some of these mechanisms are also shared by a different family of proteins, termed pannexins. Importantly, these systems allow not only communication between healthy cells, but also play an important role during different types of injury. The aim of this review is to discuss the role played by both connexin hemichannels and pannexin channels in cell communication and injury. This article is part of a Special Issue entitled: The Communicating junctions, composition, structure and characteristics.
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43
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Magnotti LM, Goodenough DA, Paul DL. Deletion of oligodendrocyte Cx32 and astrocyte Cx43 causes white matter vacuolation, astrocyte loss and early mortality. Glia 2011; 59:1064-74. [PMID: 21538560 PMCID: PMC3094483 DOI: 10.1002/glia.21179] [Citation(s) in RCA: 78] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2010] [Accepted: 03/29/2011] [Indexed: 12/15/2022]
Abstract
CNS glia exhibit a variety of gap junctional interactions: between neighboring astrocytes, between neighboring oligodendrocytes, between astrocytes and oligodendrocytes, and as 'reflexive' structures between layers of myelin in oligodendrocytes. Together, these junctions are thought to form a network facilitating absorption and removal of extracellular K(+) released during neuronal activity. In mice, loss of the two major oligodendrocyte connexins causes severe demyelination and early mortality, while loss of the two major astrocyte connexins causes mild dysmyelination and sensorimotor impairment, suggesting that reflexive and/or oligo-oligo coupling may be more important for the maintenance of myelin than other forms. To further explore the functional relationships between glial connexins, we generated double knockout mice lacking one oligodendrocyte and one astrocyte connexin. Cx32-Cx43 dKO animals develop white matter vacuolation without obvious ultrastructural abnormalities in myelin. Progressive loss of astrocytes but not oligodendrocytes or microglia accompanies sensorimotor impairment, seizure activity and early mortality at around 16 weeks of age. Our data reveal an unexpected role for connexins in the survival of white matter astrocytes, requiring the expression of particular isoforms in both oligodendrocytes and astrocytes.
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Affiliation(s)
- Laura M. Magnotti
- Department of Neurobiology, Harvard Medical School, 220 Longwood Ave., Boston, MA 02115
| | - Daniel A. Goodenough
- Department of Cell Biology, Harvard Medical School, 220 Longwood Ave., Boston, MA 02115
| | - David L. Paul
- Department of Neurobiology, Harvard Medical School, 220 Longwood Ave., Boston, MA 02115
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44
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Fang X, Huang T, Zhu Y, Yan Q, Chi Y, Jiang JX, Wang P, Matsue H, Kitamura M, Yao J. Connexin43 hemichannels contribute to cadmium-induced oxidative stress and cell injury. Antioxid Redox Signal 2011; 14:2427-39. [PMID: 21235398 PMCID: PMC3096519 DOI: 10.1089/ars.2010.3150] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
We investigated the potential involvement of connexin hemichannels in cadmium ions (Cd(2+))-elicited cell injury. Transfection of LLC-PK1 cells with a wild-type connexin43 (Cx43) sensitized them to Cd(2+)-elicited cell injury. The cell susceptibility to Cd(2+) was increased by depletion of glutathione (GSH) with DL-buthionine-[S,R]-sulfoximine, and decreased by N-acetyl-cysteine or glutathione reduced ethyl ester. Fibroblasts derived from Cx43 wild-type (Cx43+/+) and knockout (Cx43-/-) fetal littermates displayed different susceptibility to Cd(2+). Cd(2+) induced a higher concentration of reactive oxygen species, a stronger activation c-Jun N-terminal kinase, and significantly more severe cell injury in Cx43+/+ fibroblasts, as compared with Cx43-/- fibroblasts. Cd(2+) caused a reduction in intracellular GSH, whereas it elevated extracellular GSH. This effect of Cd(2+) was more dramatic in Cx43+/+ than Cx43-/- fibroblasts. Treatment of Cx43+/+ fibroblasts with Cd(2+) caused a Cx43 hemichannel-dependent influx of Lucifer Yellow and efflux of ATP. Collectively, our study demonstrates that Cx43 sensitizes cells to Cd(2+)-initiated cytotoxicity, possibly through hemichannel-mediated effects on intracellular oxidative status.
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Affiliation(s)
- Xin Fang
- Department of Molecular Signaling, University of Yamanashi, Chuo, Yamanashi, Japan
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45
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Decrock E, Vinken M, Bol M, D'Herde K, Rogiers V, Vandenabeele P, Krysko DV, Bultynck G, Leybaert L. Calcium and connexin-based intercellular communication, a deadly catch? Cell Calcium 2011; 50:310-21. [PMID: 21621840 DOI: 10.1016/j.ceca.2011.05.007] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2011] [Revised: 05/03/2011] [Accepted: 05/05/2011] [Indexed: 10/18/2022]
Abstract
Ca(2+) is known as a universal messenger mediating a wide variety of cellular processes, including cell death. In fact, this ion has been proposed as the 'cell death master', not only at the intracellular but also at the intercellular level. The most direct form of intercellular spread of cell death is mediated by gap junction channels. These channels have been shown to propagate cell death as well as cell survival signals between the cytoplasm of neighbouring cells, reflecting the dual role of Ca(2+) signals, i.e. cell death versus survival. Its precursor, the unopposed hemichannel (half of a gap junction channel), has recently joined in as a toxic pore connecting the intracellular with the extracellular environment and allowing the passage of a range of substances. The biochemical nature of the so-called intercellular cell death molecule, transferred through gap junctions or released/taken up via hemichannels, remains elusive but several studies pinpoint Ca(2+) itself or its messenger inositol trisphosphate as the responsible masters in crime. Although direct evidence is still lacking, indirect data including Ca(2+) involvement in intercellular communication and cell death, and effects of intercellular communication on intracellular Ca(2+) homeostasis, support this hypothesis. In addition, hemichannels and their molecular building blocks, connexin or pannexin proteins, may exert their effects on Ca(2+)-dependent cell death at the intracellular level, independently from their channel functions. This review provides a cutting edge overview of the current knowledge and underscores the intimate connection between intercellular communication, Ca(2+) signalling and cell death.
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Affiliation(s)
- Elke Decrock
- Department of Basic Medical Sciences - Physiology Group, Faculty of Medicine and Health Sciences, Ghent University, B-9000 Ghent, Belgium
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Heat shock protein 90 mediates anti-apoptotic effect of diazoxide by preventing the cleavage of Bid in hypothermic preservation rat hearts. J Heart Lung Transplant 2011; 30:928-34. [PMID: 21620734 DOI: 10.1016/j.healun.2011.04.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2010] [Revised: 03/11/2011] [Accepted: 04/19/2011] [Indexed: 11/24/2022] Open
Abstract
BACKGROUND Successful organ preservation is the premise for clinical organ transplantation. The present study investigated whether heat shock protein 90 (Hsp90) is important in the anti-apoptotic effect of diazoxide in hypothermic preservation rat hearts. METHODS Isolated rat hearts were preserved in Celsior solution, with or without diazoxide, for 3 to 9 hours, followed by 60 minutes of reperfusion. Cell apoptosis was assessed by terminal deoxynucleotide transferase-mediated deoxy uridine triphosphate nick-end labeling. The left ventricular developed pressure (LVDP) was recorded. Expression of Hsp90 protein and cleavage of Bid were detected by Western blot and polymerase chain reaction. RESULTS After hypothermic preservation for 3 to 9 hours, the LVDP recovery rate significantly decreased and cardiomyocyte apoptosis index increased in a time-dependent manner. When compared with the 9-hour preservation group, Celsior solution supplemented with diazoxide significantly enhanced the LVDP recovery rate and decreased the apoptosis index. The cleavage of Bid increased after 9 hours of hypothermic preservation, which was inhibited by Celsior solution supplemented with diazoxide. Hypothermic preservation of rat hearts for 9 hours decreased the expression of Hsp90, whereas diazoxide supplementation significantly increased the expression of Hsp90. The Hsp90 inhibitor 17-allylamino-17-demethoxy-geldanamycin inhibited the diazoxide-induced decrease in cleavage of Bid, improvement of cardiac function, and decrease of apoptosis. Hsp90 inhibitor had no effect on the diazoxide-induced increase of total Cx43 protein expression in hearts preserved 9 hours, but inhibited the diazoxide-induced increase of mitochondrial Cx43 protein level. CONCLUSION Hsp90 might mediate diazoxide-induced cardioprotection against apoptosis in hypothermic preservation heart by preventing the cleavage of Bid.
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Jiao L, Zhang J, Li Z, Liu H, Chen Y, Xu S. Edaravone alleviates delayed neuronal death and long-dated cognitive dysfunction of hippocampus after transient focal ischemia in Wistar rat brains. Neuroscience 2011; 182:177-83. [PMID: 21241778 DOI: 10.1016/j.neuroscience.2011.01.017] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2010] [Revised: 01/06/2011] [Accepted: 01/07/2011] [Indexed: 01/02/2023]
Abstract
Edaravone is currently being used in acute ischemic stroke both in clinical and experimental research as a potent antioxidant. Here we explore the effects of edaravone on delayed neuronal death (DND) and long-dated cognitive dysfunction of hippocampus after cerebral ischemia-reperfusion (IR) injury and explain the underlying mechanisms and pathways. Our findings suggested that edaravone not only significantly alleviated delayed neuronal death and cognitive dysfunction of hippocampus after cerebral focal ischemia, but also markedly decreased malondialdehyde (MDA) levels. In addition, edaravone increased superoxide dismutase (SOD) levels and reduced the levels of inflammatory cytokines such as IL-1β and TNF-α expression; edaravone, also suppressed glial fibrillary acidic protein (GFAP) proliferation at days 3, 7 and 30 after reperfusion. Overall, the consensus emerging from this body of data indicated that edaravone exerts a later neuroprotective effect to hippocampus through its ability to inhibit inflammation, suppression of astrocyte activation and scavenging free radicals in stroke events.
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Affiliation(s)
- L Jiao
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, PR China
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Qi J, Chi L, Bynum D, Banes AJ. Gap junctions in IL-1β-mediated cell survival response to strain. J Appl Physiol (1985) 2011; 110:1425-31. [PMID: 21212244 DOI: 10.1152/japplphysiol.00477.2010] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Mechanical stimuli play important roles in proliferation and differentiation of connective tissue cells, and development and homeostatic maintenance of tissues. However, excessive mechanical loading to a tissue can injure cells and disrupt the matrix, as occurs in tendinopathy. Tendinopathy is a common clinical problem in athletes and in many occupational settings due to overuse of the tendon. Moreover, interleukin (IL)-1β is generally considered to be a "bad" cytokine, activating NF-κb and cell death and inducing matrix metalloproteinase (MMPs 1, 2, 3) expression and matrix destruction. However, activated NF-κB can also drive a cell survival pathway. We have reported that cyclic strain induced tenocyte death in three-dimensional (3D) cultures, and IL-1β could promote cell survival under strain. Therefore, it was hypothesized that 1) cyclic strain could induce cell death in tenocytes as observed in pathologic tendons in vivo; 2) a gene expression profile indicative of tendinopathy could be identified; and 3) low-dose IL-1β could protect cells from strain-induced, tendinopathy-like changes. Human tenocytes were cultured in 3D type I collagen hydrogels and subjected to 3.5% elongation at 1 Hz for 1 h/day for up to 5 days with or without IL-1β. Real-time RT-PCR data showed that cyclic strain regulated the expression of tendinopathy marker genes in a manner similar to that found in pathological tendons from patients and that addition of IL-1β reversed the gene expression changes to control levels. Results of further studies showed that IL-1β may modulate cell survival through upregulating the expression of connexin 43, which is involved in the modulation of cell death/survival in a variety of cells and tissues. The elucidation of the mechanisms underlying strain-induced cell death and recovery from strain injury will facilitate our understanding of the pathogenesis of tendinopathy and may lead to the discovery of new molecular targets for early diagnosis and treatment of tendinopathy.
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Affiliation(s)
- Jie Qi
- Flexcell International, Hillsborough, NC 27278, USA
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Homkajorn B, Sims N, Muyderman H. Connexin 43 regulates astrocytic migration and proliferation in response to injury. Neurosci Lett 2010; 486:197-201. [DOI: 10.1016/j.neulet.2010.09.051] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2010] [Revised: 09/15/2010] [Accepted: 09/16/2010] [Indexed: 11/16/2022]
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Antiarrhythmic effect mediated by κ-opioid receptor is associated with Cx43 stabilization*. Crit Care Med 2010; 38:2365-76. [DOI: 10.1097/ccm.0b013e3181fa0437] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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