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Mickus R, Raškevičius V, Sarapinienė I, Mikalayeva V, Prekeris R, Skeberdis VA. Phosphorylation-dependent allosteric regulation of Cx43 gap junction inhibitor potency. Biomed Pharmacother 2024; 174:116550. [PMID: 38593702 DOI: 10.1016/j.biopha.2024.116550] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2024] [Revised: 03/28/2024] [Accepted: 04/04/2024] [Indexed: 04/11/2024] Open
Abstract
Physiological and pathological processes such as homeostasis, embryogenesis, development, tumorigenesis, and cell movement depend on the intercellular communication through gap junctions (GJIC). Connexin (Cx)-based GJ channels are formed of two apposing hemichannels in the contiguous cells and provide a direct pathway for electrical and metabolic intercellular communication. The main modulators of GJ conductance are transjunctional voltage, intracellular pH, Ca2+, Mg2+, and phosphorylation. Chemical modulators of GJIC are being used in cases of various intercellular communication-dependent diseases. In this study, we used molecular docking, dual whole-cell patch-clamp, and Western blotting to investigate the impact of connexin phosphorylation on GJ chemical gating by α-pinene and other GJ inhibitors (octanol, carbenoxolone, mefloquine, intracellular pH, glycyrrhetinic acid, and sevoflurane) in HeLa cells expressing exogenous Cx43 (full length and truncated at amino acid 258) and other connexins typical of heart and/or nervous system (Cx36, Cx40, Cx45, and Cx47), and in cells expressing endogenous Cx43 (Novikoff and U-87). We found that Ca2+-regulated kinases, such as Ca2+/calmodulin-dependent kinase II, atypical protein kinase C, cyclin-dependent kinase, and Pyk2 kinase may allosterically modulate the potency of α-pinene through phosphorylation of Cx43 C-terminus. The identified new phenomenon was Cx isoform-, inhibitor-, and cell type-dependent. Overall, these results suggest that compounds, the potency of which depends on receptor phosphorylation, might be of particular interest in developing targeted therapies for diseases accompanied by high kinase activity, such as cardiac arrhythmias, epilepsy, stroke, essential tremor, inflammation, and cancer.
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Affiliation(s)
- Rokas Mickus
- Institute of Cardiology, Lithuanian University of Health Sciences, Kaunas LT-50162, Lithuania
| | - Vytautas Raškevičius
- Institute of Cardiology, Lithuanian University of Health Sciences, Kaunas LT-50162, Lithuania
| | - Ieva Sarapinienė
- Institute of Cardiology, Lithuanian University of Health Sciences, Kaunas LT-50162, Lithuania
| | - Valeryia Mikalayeva
- Institute of Cardiology, Lithuanian University of Health Sciences, Kaunas LT-50162, Lithuania
| | - Rytis Prekeris
- Department of Cell and Developmental Biology, University of Colorado Anschutz Medical Campus, Aurora, CO 80015, USA
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2
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Sharma V, Sharma A, Wadje BN, Bharate SB. Benzopyrone, a privileged scaffold in drug discovery: An overview of FDA-approved drugs and clinical candidates. Med Res Rev 2024. [PMID: 38532246 DOI: 10.1002/med.22032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2023] [Revised: 02/02/2024] [Accepted: 03/04/2024] [Indexed: 03/28/2024]
Abstract
Natural products have always served as an important source of drugs for treating various diseases. Among various privileged natural product scaffolds, the benzopyrone class of compounds has a substantial presence among biologically active compounds. One of the pioneering anticoagulant drugs, warfarin approved in 1954 bears a benzo-α-pyrone (coumarin) nucleus. The widely investigated psoriasis drugs, methoxsalen, and trioxsalen, also contain a benzo-α-pyrone nucleus. Benzo-γ-pyrone (chromone) containing drugs, cromoglic acid, and pranlukast were approved as treatments for asthma in 1982 and 2007, respectively. Numerous other small molecules with a benzopyrone core are under clinical investigation. The present review discusses the discovery, absorption, distribution, metabolism, excretion properties, and synthetic approaches for the Food and Drug Administration-approved and clinical-stage benzopyrone class of compounds. The role of the pyrone core in biological activity has also been discussed. The present review unravels the potential of benzopyrone core in medicinal chemistry and drug development.
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Affiliation(s)
- Venu Sharma
- Natural Products and Medicinal Chemistry Division, CSIR-Indian Institute of Integrative Medicine, Jammu, Jammu and Kashmir, India
| | - Ankita Sharma
- Natural Products and Medicinal Chemistry Division, CSIR-Indian Institute of Integrative Medicine, Jammu, Jammu and Kashmir, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, Uttar Pradesh, India
| | - Bhagyashri N Wadje
- Department of Natural Products and Medicinal Chemistry Division, CSIR-Indian Institute of Chemical Technology, Hyderabad, Telangana, India
| | - Sandip B Bharate
- Natural Products and Medicinal Chemistry Division, CSIR-Indian Institute of Integrative Medicine, Jammu, Jammu and Kashmir, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, Uttar Pradesh, India
- Department of Natural Products and Medicinal Chemistry Division, CSIR-Indian Institute of Chemical Technology, Hyderabad, Telangana, India
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3
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Sidell N, Rajakumar A. Retinoic Acid Action in Cumulus Cells: Implications for Oocyte Development and In Vitro Fertilization. Int J Mol Sci 2024; 25:1709. [PMID: 38338985 PMCID: PMC10855907 DOI: 10.3390/ijms25031709] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2023] [Revised: 01/15/2024] [Accepted: 01/22/2024] [Indexed: 02/12/2024] Open
Abstract
In the field of human in vitro fertilization (IVF), selecting the best oocyte for freezing or embryo for transfer remains an important focus of clinical practice. Although several techniques are and have been used for this goal, results have generally not been favorable and/or are invasive such that damage to some embryos occurs, resulting in a reduced number of healthy births. Therefore, the search continues for non-invasive oocyte and embryo quality markers that signal the development of high-quality embryos. Multiple studies indicate the important positive effects of retinoic acid (RA) on oocyte maturation and function. We previously showed that a high follicular fluid (FF) RA concentration at the time of oocyte retrieval in IVF protocols was associated with oocytes, giving rise to the highest quality embryos, and that cumulus granulosa cells (CGCs) are the primary source of follicle RA synthesis. Data also demonstrated that connexin-43 (Cx43), the main connexin that forms gap junctions in CGCs, is regulated by RA and that RA induces a rapid increase in gap junction communication. Here, we hypothesize that CGC RA plays a causal role in oocyte competency through its action on Cx43 and, as such, may serve as a biomarker of oocyte competence. Multiple studies have demonstrated the requirement for Cx43 in CGCs for the normal progression of folliculogenesis, and that the increased expression of this connexin is linked to the improved developmental competence of the oocyte. The data have shown that RA can up-regulate gap junction intercellular communication (GJIC) in the cumulus-oocyte complex via a non-genomic mechanism that results in the dephosphorylation of Cx43 and enhanced GJIC. Recognizing the positive role played by gap junctions in CGCs in oocyte development and the regulation of Cx43 by RA, the findings have highlighted the possibility that CGC RA levels may serve as a non-invasive indicator for selecting high-quality oocytes for IVF procedures. In addition, the data suggest that the manipulation of Cx43 with retinoid compounds could provide new pharmacological approaches to improve IVF outcomes in cases of failed implantation, recurrent miscarriage, or in certain diseases that are characterized by reduced fecundity, such as endometriosis.
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Affiliation(s)
- Neil Sidell
- Department of Gynecology & Obstetrics, Emory University School of Medicine, Atlanta, GA 30322, USA;
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4
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Fiori MC, Altenberg GA. Purification, Reconstitution, and Functional Analysis of Connexin Hemichannels. Methods Mol Biol 2024; 2801:1-16. [PMID: 38578409 DOI: 10.1007/978-1-0716-3842-2_1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/06/2024]
Abstract
Connexins are the proteins that form the gap junction channels that are essential for cell-to-cell communication. These channels are formed by head-to-head docking of hemichannels (each from one of two adjacent cells). Free "undocked" hemichannels at the plasma membrane are mostly closed, although they are still important under physiological conditions. However, abnormal and sustained increase in hemichannel activity due to connexin mutations or acquired conditions can produce or contribute to cell damage. For example, mutations of Cx26, a connexin isoform, can increase hemichannel activity and cause deafness. Studies using purified isolated systems under well-controlled conditions are essential for a full understanding of molecular mechanisms of hemichannel function under normal conditions and in disease, and here, we present methodology for the expression, purification, and functional analysis of hemichannels formed by Cx26.
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Affiliation(s)
- Mariana C Fiori
- Clinical Research Institute, Texas Tech University Health Sciences Center, Lubbock, TX, USA
| | - Guillermo A Altenberg
- Department of Cell Physiology and Molecular Biophysics, and Center for Membrane Protein Research, Texas Tech University Health Sciences Center, Lubbock, TX, USA.
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5
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Zhang M, Wang ZZ, Chen NH. Connexin 43 Phosphorylation: Implications in Multiple Diseases. Molecules 2023; 28:4914. [PMID: 37446576 DOI: 10.3390/molecules28134914] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2023] [Revised: 06/16/2023] [Accepted: 06/20/2023] [Indexed: 07/15/2023] Open
Abstract
Connexin 43 (Cx43) is most widely distributed in mammals, especially in the cardiovascular and nervous systems. Its phosphorylation state has been found to be regulated by the action of more than ten kinases and phosphatases, including mitogen-activated protein kinase/extracellular signaling and regulating kinase signaling. In addition, the phosphorylation status of different phosphorylation sites affects its own synthesis and assembly and the function of the gap junctions (GJs) to varying degrees. The phosphorylation of Cx43 can affect the permeability, electrical conductivity, and gating properties of GJs, thereby having various effects on intercellular communication and affecting physiological or pathological processes in vitro and in vivo. Therefore, clarifying the relationship between Cx43 phosphorylation and specific disease processes will help us better understand the disease. Based on the above clinical and preclinical findings, we present in this review the functional significance of Cx43 phosphorylation in multiple diseases and discuss the potential of Cx43 as a drug target in Cx43-related disease pathophysiology, with an emphasis on the importance of connexin 43 as an emerging therapeutic target in cardiac and neuroprotection.
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Affiliation(s)
- Meng Zhang
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica & Neuroscience Center, Chinese Academy of Medical Science and Peking Union Medical College, Beijing 100050, China
| | - Zhen-Zhen Wang
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica & Neuroscience Center, Chinese Academy of Medical Science and Peking Union Medical College, Beijing 100050, China
| | - Nai-Hong Chen
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica & Neuroscience Center, Chinese Academy of Medical Science and Peking Union Medical College, Beijing 100050, China
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6
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Martin EA, Michel JC, Kissinger JS, Echeverry FA, Lin YP, O'Brien J, Pereda AE, Miller AC. Neurobeachin controls the asymmetric subcellular distribution of electrical synapse proteins. Curr Biol 2023; 33:2063-2074.e4. [PMID: 37172585 PMCID: PMC10266475 DOI: 10.1016/j.cub.2023.04.049] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2022] [Revised: 01/27/2023] [Accepted: 04/19/2023] [Indexed: 05/15/2023]
Abstract
The subcellular positioning of synapses and their specialized molecular compositions form the fundamental basis of neural circuits. Like chemical synapses, electrical synapses are constructed from an assortment of adhesion, scaffolding, and regulatory molecules, yet little is known about how these molecules localize to specific neuronal compartments. Here, we investigate the relationship between the autism- and epilepsy-associated gene Neurobeachin, the neuronal gap junction channel-forming Connexins, and the electrical synapse scaffold ZO1. Using the zebrafish Mauthner circuit, we find Neurobeachin localizes to the electrical synapse independently of ZO1 and Connexins. By contrast, we show Neurobeachin is required postsynaptically for the robust localization of ZO1 and Connexins. We demonstrate that Neurobeachin binds ZO1 but not Connexins. Finally, we find Neurobeachin is required to restrict electrical postsynaptic proteins to dendrites, but not electrical presynaptic proteins to axons. Together, the results reveal an expanded understanding of electrical synapse molecular complexity and the hierarchical interactions required to build neuronal gap junctions. Further, these findings provide novel insight into the mechanisms by which neurons compartmentalize the localization of electrical synapse proteins and provide a cell biological mechanism for the subcellular specificity of electrical synapse formation and function.
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Affiliation(s)
- E Anne Martin
- Institute of Neuroscience, University of Oregon, Eugene, OR 97403, USA.
| | | | - Jane S Kissinger
- Institute of Neuroscience, University of Oregon, Eugene, OR 97403, USA
| | - Fabio A Echeverry
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Ya-Ping Lin
- Department of Ophthalmology & Visual Science, University of Texas Health Science Center at Houston, Houston, TX 77030, USA
| | - John O'Brien
- Department of Ophthalmology & Visual Science, University of Texas Health Science Center at Houston, Houston, TX 77030, USA
| | - Alberto E Pereda
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Adam C Miller
- Institute of Neuroscience, University of Oregon, Eugene, OR 97403, USA.
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7
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Puts R, Khaffaf A, Shaka M, Zhang H, Raum K. Focused Low-Intensity Pulsed Ultrasound (FLIPUS) Mitigates Apoptosis of MLO-Y4 Osteocyte-like Cells. Bioengineering (Basel) 2023; 10:bioengineering10030387. [PMID: 36978778 PMCID: PMC10045139 DOI: 10.3390/bioengineering10030387] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Revised: 03/01/2023] [Accepted: 03/15/2023] [Indexed: 03/30/2023] Open
Abstract
Long cytoplasmic processes of osteocytes orchestrate bone activity by integration of biochemical and mechanical signals and regulate load-induced bone adaptation. Low-Intensity Pulsed Ultrasound (LIPUS) is a clinically used technique for fracture healing that delivers mechanical impulses to the damaged bone tissue in a non-invasive and non-ionizing manner. The mechanism of action of LIPUS is still controversially discussed in the scientific community. In this study, the effect of focused LIPUS (FLIPUS) on the survival of starved MLO-Y4 osteocytes was investigated in vitro. Osteocytes stimulated for 10 min with FLIPUS exhibited extended dendrites, which formed frequent connections to neighboring cells and spanned longer distances. The sonicated cells displayed thick actin bundles and experienced increase in expression of connexin 43 (Cx43) proteins, especially on their dendrites, and E11 glycoprotein, which is responsible for the elongation of cellular cytoplasmic processes. After stimulation, expression of cell growth and survival genes as well as genes related to cell-cell communication was augmented. In addition, cell viability was improved after the sonication, and a decrease in ATP release in the medium was observed. In summary, FLIPUS mitigated apoptosis of starved osteocytes, which is likely related to the formation of the extensive dendritic network that ensured cell survival.
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Affiliation(s)
- Regina Puts
- Center for Biomedicine, Charité-Universitätsmedizin, 12203 Berlin, Germany
- Berlin Institute of Health (BIH) Center for Regenerative Therapies, Charité-Universitätsmedizin, 13353 Berlin, Germany
| | - Aseel Khaffaf
- Center for Biomedicine, Charité-Universitätsmedizin, 12203 Berlin, Germany
| | - Maria Shaka
- Center for Biomedicine, Charité-Universitätsmedizin, 12203 Berlin, Germany
| | - Hui Zhang
- Center for Biomedicine, Charité-Universitätsmedizin, 12203 Berlin, Germany
| | - Kay Raum
- Center for Biomedicine, Charité-Universitätsmedizin, 12203 Berlin, Germany
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8
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Lee SN, Cho HJ, Jeong H, Ryu B, Lee HJ, Kim M, Yoo J, Woo JS, Lee HH. Cryo-EM structures of human Cx36/GJD2 neuronal gap junction channel. Nat Commun 2023; 14:1347. [PMID: 36906653 PMCID: PMC10008584 DOI: 10.1038/s41467-023-37040-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2022] [Accepted: 02/28/2023] [Indexed: 03/13/2023] Open
Abstract
Connexin 36 (Cx36) is responsible for signal transmission in electrical synapses by forming interneuronal gap junctions. Despite the critical role of Cx36 in normal brain function, the molecular architecture of the Cx36 gap junction channel (GJC) is unknown. Here, we determine cryo-electron microscopy structures of Cx36 GJC at 2.2-3.6 Å resolutions, revealing a dynamic equilibrium between its closed and open states. In the closed state, channel pores are obstructed by lipids, while N-terminal helices (NTHs) are excluded from the pore. In the open state with pore-lining NTHs, the pore is more acidic than those in Cx26 and Cx46/50 GJCs, explaining its strong cation selectivity. The conformational change during channel opening also includes the α-to-π-helix transition of the first transmembrane helix, which weakens the protomer-protomer interaction. Our structural analyses provide high resolution information on the conformational flexibility of Cx36 GJC and suggest a potential role of lipids in the channel gating.
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Affiliation(s)
- Seu-Na Lee
- Department of Life Sciences, Korea University, Seoul, 02841, Republic of Korea
| | - Hwa-Jin Cho
- Department of Chemistry, College of Natural Sciences, Seoul National University, Seoul, 08826, Korea
| | - Hyeongseop Jeong
- Center for Research Equipment, Korea Basic Science Institute, Chungcheongbuk-do, 28119, Korea
| | - Bumhan Ryu
- Research Solution Center, Institute for Basic Science, Daejeon, 34126, Republic of Korea
| | - Hyuk-Joon Lee
- Department of Life Sciences, Korea University, Seoul, 02841, Republic of Korea
| | - Minsoo Kim
- Department of Physics, Sungkyunkwan University, Suwon, 16419, South Korea
| | - Jejoong Yoo
- Department of Physics, Sungkyunkwan University, Suwon, 16419, South Korea
| | - Jae-Sung Woo
- Department of Life Sciences, Korea University, Seoul, 02841, Republic of Korea.
| | - Hyung Ho Lee
- Department of Chemistry, College of Natural Sciences, Seoul National University, Seoul, 08826, Korea.
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Mulchandani V, Banerjee A, Vadlamannati AV, Kumar S, Das Sarma J. Connexin 43 trafficking and regulation of gap junctional intercellular communication alters ovarian cancer cell migration and tumorigenesis. Biomed Pharmacother 2023; 159:114296. [PMID: 36701988 DOI: 10.1016/j.biopha.2023.114296] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2022] [Revised: 01/16/2023] [Accepted: 01/20/2023] [Indexed: 01/27/2023] Open
Abstract
Ovarian cancer persists to be the most lethal gynecological malignancy, demanding rigorous treatments involving radio-chemotherapy that trigger toxicity and consequently mortality among patients. An improved understanding of the disease progression may pioneer curative therapies. Mouse epithelial ovarian cancer cell lines, ID8 and ID8-VEGF (overexpressing VEGF) were intraperitoneally injected in C57BL/6 female mice to develop a Syngeneic Ovarian cancer mouse model. It was observed that ID8-VEGF cells were able to induce aggressive tumor growth in mice compared to ID8 cells. Furthermore, results of the current in vitro study comparing ID8 and ID8-VEGF demonstrated that highly tumorigenic ID8-VEGF had reduced gap junctional intercellular communication (GJIC) due to intracellular Connexin 43 (Cx43) expression. Additionally, ID8 cells with reduced tumorigenic capability expressed significant GJIC. Furthermore, loss of GJIC in ID8-VEGF cells induced shorter tunneling nanotube formations, while ID8 cells develops longer tunneling nanotube to maintain cellular crosstalk. The administration of a pharmacological drug 4-phenylbutyrate (4PBA) ensured the restoration of GJIC in both the ovarian cancer cell lines. Additionally, 4PBA treatment significantly inhibited the migration of ovarian cancer cell lines and tumor formation in ovarian cancer mice models. In summary, the 4PBA-mediated restoration of GJIC suppressed migration (in vitro) and tumorigenesis (in vivo) of ovarian cancer cells. The present study suggests that Cx43 assembled GJIC and its supportive signaling pathways are a prospective target for restricting ovarian cancer progression.
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Affiliation(s)
- Vaishali Mulchandani
- Department of Biological Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur 741246, India
| | - Anurag Banerjee
- Department of Biological Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur 741246, India
| | - Arunima Vijaya Vadlamannati
- Department of Biological Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur 741246, India
| | - Saurav Kumar
- Department of Biological Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur 741246, India
| | - Jayasri Das Sarma
- Department of Biological Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur 741246, India; Department of Ophthalmology, University of Pennsylvania, Philadelphia, USA.
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Chang CWT, Poudyal N, Verdugo DA, Peña F, Stehberg J, Retamal MA. KI04 an Aminoglycosides-Derived Molecule Acts as an Inhibitor of Human Connexin46 Hemichannels Expressed in HeLa Cells. Biomolecules 2023; 13:411. [PMID: 36979346 PMCID: PMC10046693 DOI: 10.3390/biom13030411] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2023] [Revised: 02/12/2023] [Accepted: 02/16/2023] [Indexed: 02/24/2023] Open
Abstract
BACKGROUND Connexins (Cxs) are proteins that help cells to communicate with the extracellular media and with the cytoplasm of neighboring cells. Despite their importance in several human physiological and pathological conditions, their pharmacology is very poor. In the last decade, some molecules derived from aminoglycosides have been developed as inhibitors of Cxs hemichannels. However, these studies have been performed in E. coli, which is a very simple model. Therefore, our main goal is to test whether these molecules have similar effects in mammalian cells. METHODS We transfected HeLa cells with the human Cx46tGFP and characterized the effect of a kanamycin-derived molecule (KI04) on Cx46 hemichannel activity by time-lapse recordings, changes in phosphorylation by Western blot, localization by epifluorescence, and possible binding sites by molecular dynamics (MD). RESULTS We observed that kanamycin and KI04 were the most potent inhibitors of Cx46 hemichannels among several aminoglycosides, presenting an IC50 close to 10 μM. The inhibitory effect was not associated with changes in Cx46 electrophoretic mobility or its intracellular localization. Interestingly, 5 mM DTT did not reverse KI04 inhibition, but the KI04 effect completely disappeared after washing out KI04 from the recording media. MD analysis revealed two putative binding sites of KI04 in the Cx46 hemichannel. RESULTS These results demonstrate that KI04 could be used as a Cx46 inhibitor and could help to develop future selective Cx46 inhibitors.
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Affiliation(s)
- Cheng-Wei T. Chang
- Department of Chemistry and Biochemistry, Utah State University, Logan, UT 84322-0300, USA
| | - Naveena Poudyal
- Department of Chemistry and Biochemistry, Utah State University, Logan, UT 84322-0300, USA
| | - Daniel A. Verdugo
- Laboratorio de Neurobiología, Facultad de Medicina y Facultad de Ciencias de la Vida, Instituto de Ciencias Biomédicas, Universidad Andres Bello, Santiago 7780272, Chile
| | - Francisca Peña
- Laboratorio de Neurobiología, Facultad de Medicina y Facultad de Ciencias de la Vida, Instituto de Ciencias Biomédicas, Universidad Andres Bello, Santiago 7780272, Chile
| | - Jimmy Stehberg
- Laboratorio de Neurobiología, Facultad de Medicina y Facultad de Ciencias de la Vida, Instituto de Ciencias Biomédicas, Universidad Andres Bello, Santiago 7780272, Chile
| | - Mauricio A. Retamal
- Center for Membrane Protein Research, Department of Cell Physiology and Molecular Biophysics, Texas Tech University Health Sciences Center, Lubbock, TX 79430-6551, USA
- Programa de Comunicación Celular en Cáncer, Facultad de Medicina Clínica Alemana, Universidad del Desarrollo, Santiago 7610496, Chile
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11
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Zhao GL, Zhou H, Guo YH, Zhong SM, Zhou H, Li F, Lei B, Wang Z, Miao Y. Modulation of Rac1/PAK1/connexin43-mediated ATP release from astrocytes contributes to retinal ganglion cell survival in experimental glaucoma. Glia 2023; 71:1502-1521. [PMID: 36794533 DOI: 10.1002/glia.24354] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Revised: 01/31/2023] [Accepted: 02/02/2023] [Indexed: 02/17/2023]
Abstract
Connexin43 (Cx43) is a major gap junction protein in glial cells. Mutations have been found in the gap-junction alpha 1 gene encoding Cx43 in glaucomatous human retinas, suggestive of the involvement of Cx43 in the pathogenesis of glaucoma. However, how Cx43 is involved in glaucoma is still unknown. We showed that increased intraocular pressure in a glaucoma mouse model of chronic ocular hypertension (COH) downregulated Cx43, which was mainly expressed in retinal astrocytes. Astrocytes in the optic nerve head where they gather and wrap the axons (optic nerve) of retinal ganglion cells (RGCs) were activated earlier than neurons in COH retinas and the alterations in astrocytes plasticity in the optic nerve caused a reduction in Cx43 expression. A time course showed that reductions of Cx43 expression were correlated with the activation of Rac1, a member of the Rho family. Co-immunoprecipitation assays showed that active Rac1, or the downstream signaling effector PAK1, negatively regulated Cx43 expression, Cx43 hemichannel opening and astrocyte activation. Pharmacological inhibition of Rac1 stimulated Cx43 hemichannel opening and ATP release, and astrocytes were identified to be one of the main sources of ATP. Furthermore, conditional knockout of Rac1 in astrocytes enhanced Cx43 expression and ATP release, and promoted RGC survival by upregulating the adenosine A3 receptor in RGCs. Our study provides new insight into the relationship between Cx43 and glaucoma, and suggests that regulating the interaction between astrocytes and RGCs via the Rac1/PAK1/Cx43/ATP pathway may be used as part of a therapeutic strategy for managing glaucoma.
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Affiliation(s)
- Guo-Li Zhao
- State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Fudan University, Shanghai, China
| | - Hong Zhou
- State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Fudan University, Shanghai, China
| | - Yun-Hui Guo
- State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Fudan University, Shanghai, China
| | - Shu-Min Zhong
- State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Fudan University, Shanghai, China
| | - Han Zhou
- State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Fudan University, Shanghai, China
| | - Fang Li
- State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Fudan University, Shanghai, China
| | - Bo Lei
- Institute of Neuroscience and Third Affiliated Hospital, Henan Provincial People's Hospital, Henan Eye Institute, Henan Eye Hospital, People's Hospital of Zhengzhou University, Zhengzhou University, Zhengzhou, China
| | - Zhongfeng Wang
- State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Fudan University, Shanghai, China
| | - Yanying Miao
- State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Fudan University, Shanghai, China
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12
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Retamal MA, Altenberg GA. Role and Posttranslational Regulation of Cx46 Hemichannels and Gap Junction Channels in the Eye Lens. Front Physiol 2022; 13:864948. [PMID: 35431975 PMCID: PMC9006113 DOI: 10.3389/fphys.2022.864948] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2022] [Accepted: 03/14/2022] [Indexed: 12/31/2022] Open
Abstract
Connexins are a family of proteins that can form two distinct types of channels: hemichannels and gap junction channels. Hemichannels are composed of six connexin subunits and when open allow for exchanges between the cytoplasm and the extracellular milieu. Gap junction channels are formed by head-to-head docking of two hemichannels in series, each one from one of two adjacent cells. These channels allow for exchanges between the cytoplasms of contacting cells. The lens is a transparent structure located in the eye that focuses light on the retina. The transparency of the lens depends on its lack of blood irrigation and the absence of organelles in its cells. To survive such complex metabolic scenario, lens cells express Cx43, Cx46 and Cx50, three connexins isoforms that form hemichannels and gap junction channels that allow for metabolic cooperation between lens cells. This review focuses on the roles of Cx46 hemichannels and gap junction channels in the lens under physiological conditions and in the formation of cataracts, with emphasis on the modulation by posttranslational modifications.
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Affiliation(s)
- Mauricio A. Retamal
- Universidad del Desarrollo, Centro de Fisiología Celular e Integrativa, Clínica Alemana Facultad de Medicina, Santiago, Chile
- Universidad del Desarrollo, Programa de Comunicación Celular en Cáncer, Clínica Alemana Facultad de Medicina, Santiago, Chile
- Department of Cell Physiology and Molecular Biophysics, and Center for Membrane Protein Research, School of Medicine, Texas Tech University Health Sciences Center, Lubbock, TX, United States
- *Correspondence: Mauricio A. Retamal, ; Guillermo A. Altenberg,
| | - Guillermo A. Altenberg
- Department of Cell Physiology and Molecular Biophysics, and Center for Membrane Protein Research, School of Medicine, Texas Tech University Health Sciences Center, Lubbock, TX, United States
- *Correspondence: Mauricio A. Retamal, ; Guillermo A. Altenberg,
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González-Casanova JE, Durán-Agüero S, Caro-Fuentes NJ, Gamboa-Arancibia ME, Bruna T, Bermúdez V, Rojas-Gómez DM. New Insights on the Role of Connexins and Gap Junctions Channels in Adipose Tissue and Obesity. Int J Mol Sci 2021; 22:ijms222212145. [PMID: 34830025 PMCID: PMC8619175 DOI: 10.3390/ijms222212145] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Revised: 11/05/2021] [Accepted: 11/05/2021] [Indexed: 12/20/2022] Open
Abstract
Due to the inability to curb the excessive increase in the prevalence of obesity and overweight, it is necessary to comprehend in more detail the factors involved in the pathophysiology and to appreciate more clearly the biochemical and molecular mechanisms of obesity. Thus, understanding the biological regulation of adipose tissue is of fundamental relevance. Connexin, a protein that forms intercellular membrane channels of gap junctions and unopposed hemichannels, plays a key role in adipogenesis and in the maintenance of adipose tissue homeostasis. The expression and function of Connexin 43 (Cx43) during the different stages of the adipogenesis are differentially regulated. Moreover, it has been shown that cell–cell communication decreases dramatically upon differentiation into adipocytes. Furthermore, inhibition of Cx43 degradation or constitutive overexpression of Cx43 blocks adipocyte differentiation. In the first events of adipogenesis, the connexin is highly phosphorylated, which is likely associated with enhanced Gap Junction (GJ) communication. In an intermediate state of adipocyte differentiation, Cx43 phosphorylation decreases, as it is displaced from the membrane and degraded through the proteasome; thus, Cx43 total protein is reduced. Cx is involved in cardiac disease as well as in obesity-related cardiovascular diseases. Different studies suggest that obesity together with a high-fat diet are related to the production of remodeling factors associated with expression and distribution of Cx43 in the atrium.
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Affiliation(s)
- Jorge Enrique González-Casanova
- Facultad de Ciencias de la Salud, Instituto de Ciencias Biomédicas, Universidad Autónoma de Chile, Santiago 8910060, Chile; (J.E.G.-C.); (N.J.C.-F.)
| | - Samuel Durán-Agüero
- Facultad de Ciencias Para el Cuidado de la Salud, Universidad San Sebastián, Sede Los Leones, Lota 2465, Providencia, Santiago 7500000, Chile;
| | - Nelson Javier Caro-Fuentes
- Facultad de Ciencias de la Salud, Instituto de Ciencias Biomédicas, Universidad Autónoma de Chile, Santiago 8910060, Chile; (J.E.G.-C.); (N.J.C.-F.)
| | - Maria Elena Gamboa-Arancibia
- Facultad de Química y Biología, Universidad de Santiago de Chile, Av. Libertador Bernardo O’higgins 3363, Estación Central, Santiago 9170022, Chile;
| | - Tamara Bruna
- Centro de Investigación Austral Biotech, Facultad de Ciencias, Universidad Santo Tomás, Avenida Ejercito 146, Santiago 8320000, Chile;
| | - Valmore Bermúdez
- Facultad de Ciencias de la Salud, Universidad Simón Bolívar, Barranquilla 080002, Colombia;
| | - Diana Marcela Rojas-Gómez
- Escuela de Nutrición y Dietética, Facultad de Medicina, Universidad Andres Bello, Santiago 8370321, Chile
- Correspondence: ; Tel.: +56-226618559
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Mitochondria and the Tumour Microenvironment in Blood Cancer. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2021; 1329:181-203. [PMID: 34664240 DOI: 10.1007/978-3-030-73119-9_10] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/10/2023]
Abstract
The bone marrow (BM) is a complex organ located within the cavities of bones. The main function of the BM is to produce all the blood cells required for a normal healthy blood system. As with any major organ, many diseases can arise from errors in bone marrow function, including non-malignant disorders such as anaemia and malignant disorders such as leukaemias. This article will explore the role of the bone marrow, in normal and diseased haematopoiesis, with an emphasis on the requirement for intercellular mitochondrial transfer in leukaemia.
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Association Between Adenosine A 2A Receptors and Connexin 43 Regulates Hemichannels Activity and ATP Release in Astrocytes Exposed to Amyloid-β Peptides. Mol Neurobiol 2021; 58:6232-6248. [PMID: 34476674 DOI: 10.1007/s12035-021-02538-z] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Accepted: 08/17/2021] [Indexed: 12/31/2022]
Abstract
Increasing evidence implicates astrocytes and the associated purinergic modulation in Alzheimer's disease (AD), characterized by cognitive deficits involving the extracellular amyloid-β peptides (Aβ) accumulation. Aβ can affect astrocytic gliotransmitters release, namely ATP, which is rapidly metabolized into adenosine by ecto-5'-nucleotidase, CD73, resulting in adenosine A2A receptors (A2AR) activation that bolsters neurodegeneration. AD's brains exhibit an upregulation of A2AR and of connexin 43 (Cx43), which in astrocytes forms hemichannels that can mediate ATP release. However, a coupling between astrocytic A2AR and Cx43 remains to be established. This was now investigated using astrocytic primary cultures exposed to Aβ1-42 peptides. Aβ triggered ATP release through Cx43 hemichannels, a process blocked by A2AR antagonists and mimicked by selective A2AR activation. A2AR directly regulated hemichannels activity and prevented Cx43 upregulation and phosphorylation observed in Aβ1-42-exposed astrocytes. Moreover, a proximity ligand assay revealed a physical association between astrocytic A2AR and Cx43. Finally, the blockade of CD73-mediated extracellular formation of ATP-derived adenosine prevented the Aβ-induced increase of Cx43 hemichannel activity and of ATP release. Overall, the data identify a feed-forward loop involving astrocytic A2AR and Cx43 hemichannels, whereby A2AR increase Cx43 hemichannel activity leading to increased ATP release, which is converted into adenosine by CD73, sustaining the increased astrocytic A2AR activity in AD-like conditions.
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Retamal MA, Fernandez-Olivares A, Stehberg J. Over-activated hemichannels: A possible therapeutic target for human diseases. Biochim Biophys Acta Mol Basis Dis 2021; 1867:166232. [PMID: 34363932 DOI: 10.1016/j.bbadis.2021.166232] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2021] [Revised: 07/21/2021] [Accepted: 07/26/2021] [Indexed: 12/14/2022]
Abstract
In our body, all the cells are constantly sharing chemical and electrical information with other cells. This intercellular communication allows them to respond in a concerted way to changes in the extracellular milieu. Connexins are transmembrane proteins that have the particularity of forming two types of channels; hemichannels and gap junction channels. Under normal conditions, hemichannels allow the controlled release of signaling molecules to the extracellular milieu. However, under certain pathological conditions, over-activated hemichannels can induce and/or exacerbate symptoms. In the last decade, great efforts have been put into developing new tools that can modulate these over-activated hemichannels. Small molecules, antibodies and mimetic peptides have shown a potential for the treatment of human diseases. In this review, we summarize recent findings in the field of hemichannel modulation via specific tools, and how these tools could improve patient outcome in certain pathological conditions.
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Affiliation(s)
- Mauricio A Retamal
- Universidad del Desarrollo, Programa de Comunicación Celular en Cáncer, Santiago, Chile; Universidad del Desarrollo, Centro de Fisiología Celular e Integrativa, Santiago, Chile.
| | | | - Jimmy Stehberg
- Laboratorio de Neurobiología, Instituto de Ciencias Biomédicas, Facultad de medicina y Facultad de Ciencias de la Vida, Universidad Andres Bello, Santiago, Chile
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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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18
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Acosta ML, Mat Nor MN, Guo CX, Mugisho OO, Coutinho FP, Rupenthal ID, Green CR. Connexin therapeutics: blocking connexin hemichannel pores is distinct from blocking pannexin channels or gap junctions. Neural Regen Res 2021; 16:482-488. [PMID: 32985469 PMCID: PMC7996017 DOI: 10.4103/1673-5374.290097] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Compounds that block the function of connexin and pannexin protein channels have been suggested to be valuable therapeutics for a range of diseases. Some of these compounds are now in clinical trials, but for many of them, the literature is inconclusive about the molecular effect on the tissue, despite evidence of functional recovery. Blocking the different channel types has distinct physiological and pathological implications and this review describes current knowledge of connexin and pannexin protein channels, their function as channels and possible mechanisms of the channel block effect for the latest therapeutic compounds. We summarize the evidence implicating pannexins and connexins in disease, considering their homeostatic versus pathological roles, their contribution to excesive ATP release linked to disease onset and progression.
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Affiliation(s)
- Monica L Acosta
- School of Optometry and Vision Science; New Zealand National Eye Centre, University of Auckland; Centre for Brain Research, Faculty of Medical and Health Sciences, The University of Auckland; Brain Research New Zealand-Rangahau Roro Aotearoa, Auckland, New Zealand
| | - Mohd N Mat Nor
- School of Optometry and Vision Science, University of Auckland, Auckland, New Zealand; Faculty of Medicine, Universiti Sultan Zainal Abidin, Terengganu, Malaysia
| | - Cindy X Guo
- School of Optometry and Vision Science, University of Auckland, Auckland, New Zealand
| | - Odunayo O Mugisho
- Department of Ophthalmology, University of Auckland; Buchanan Ocular Therapeutics Unit, Department of Ophthalmology; New Zealand National Eye Centre, University of Auckland, Auckland, New Zealand
| | - Frazer P Coutinho
- Department of Ophthalmology, University of Auckland, Auckland, New Zealand
| | - Ilva D Rupenthal
- Department of Ophthalmology, University of Auckland; Buchanan Ocular Therapeutics Unit, Department of Ophthalmology; New Zealand National Eye Centre, University of Auckland, Auckland, New Zealand
| | - Colin R Green
- Department of Ophthalmology; New Zealand National Eye Centre, University of Auckland, Auckland, New Zealand
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Connexins-Therapeutic Targets in Cancers. Int J Mol Sci 2020; 21:ijms21239119. [PMID: 33266154 PMCID: PMC7730856 DOI: 10.3390/ijms21239119] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Revised: 11/24/2020] [Accepted: 11/26/2020] [Indexed: 12/11/2022] Open
Abstract
Connexins (Cx) are members of a protein family that forms intercellular channels localised in gap junction (GJ) plaques and single transmembrane channels called hemichannels. They participate in intercellular communication or communication between the intracellular and extracellular environments. Connexins affect cell homeostasis, growth and differentiation by enabling the exchange of metabolites or by interfering with various signalling pathways. Alterations in the functionality and the expression of connexins have been linked to the occurrence of many diseases. Connexins have been already linked to cancers, cardiac and brain disorders, chronic lung and kidney conditions and wound healing processes. Connexins have been shown either to suppress cancer tumour growth or to increase tumorigenicity by promoting cancer cell growth, migration and invasiveness. A better understanding of the complexity of cancer biology related to connexins and intercellular communication could result in the design of novel therapeutic strategies. The modulation of connexin expression may be an effective therapeutic approach in some types of cancers. Therefore, one important challenge is the search for mechanisms and new drugs, selectively modulating the expression of various connexin isoforms. We performed a systematic literature search up to February 2020 in the electronic databases PubMed and EMBASE. Our search terms were as follows: connexins, hemichannels, cancer and cancer treatment. This review aims to provide information about the role of connexins and gap junctions in cancer, as well as to discuss possible therapeutic options that are currently being studied.
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Raloxifene as Treatment for Various Types of Brain Injuries and Neurodegenerative Diseases: A Good Start. Int J Mol Sci 2020; 21:ijms21207586. [PMID: 33066585 PMCID: PMC7589740 DOI: 10.3390/ijms21207586] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Revised: 10/10/2020] [Accepted: 10/12/2020] [Indexed: 02/06/2023] Open
Abstract
Recent studies have shown that the selective estrogen receptor modulator (SERM) raloxifene had pronounced protective effects against progressing brain damage after traumatic brain injury (TBI) in mice. These studies, indicating beneficial effects of raloxifene for brain health, prompted the study of the history and present state of knowledge of this topic. It appears that, apart from raloxifene, to date, four nonrelated compounds have shown comparable beneficial effects—fucoidan, pifithrin, SMM-189 (5-dihydroxy-phenyl]-phenyl-methanone), and translocator protein (TSPO) ligands. Raloxifene, however, is ahead of the field, as for more than two decades it has been used in medical practice for various chronic ailments in humans. Thus, apart from different types of animal and cell culture studies, it has also been assessed in various human clinical trials, including assaying its effects on mild cognitive impairments. Regarding cell types, raloxifene protects neurons from cell death, prevents glial activation, ameliorates myelin damage, and maintains health of endothelial cells. At whole central nervous system (CNS) levels, raloxifene ameliorated mild cognitive impairments, as seen in clinical trials, and showed beneficial effects in animal models of Parkinson’s disease. Moreover, with stroke and TBI in animal models, raloxifene showed curative effects. Furthermore, raloxifene showed healing effects regarding multiple sclerosis (MS) and amyotrophic lateral sclerosis (ALS) in cell culture. The adverse biological signals typical of these conditions relate to neuronal activity, neurotransmitters and their receptors, plasticity, inflammation, oxidative stress, nitric oxide, calcium homeostasis, cell death, behavioral impairments, etc. Raloxifene favorably modulates these signals toward cell health—on the one hand, by modulating gene expression of the relevant proteins, for example by way of its binding to the cell nuclear estrogen receptors ERα and ERβ (genomic effects) and, on the other hand (nongenomic effects) by modulation of mitochondrial activity, reduction of oxidative stress and programmed cell death, maintaining metabolic balance, degradation of Abeta, and modulation of intracellular cholesterol levels. More specifically regarding Alzheimer’s disease, raloxifene may not cure diagnosed Alzheimer’s disease. However, the onset of Alzheimer’s disease may be delayed or arrested by raloxifene’s capability to attenuate mild cognitive impairment. Mild cognitive impairment is a condition that may precede diagnosis of Alzheimer’s disease. In this review, relatively new insights are addressed regarding the notion that Alzheimer’s disease can be caused by bacterial (as well as viral) infections, together with the most recent findings that raloxifene can counteract infections of at least some bacterial and viral strains. Thus, here, an overview of potential treatments of neurodegenerative disease by raloxifene is presented, and attention is paid to subcellular molecular biological pathways that may be involved.
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21
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Silva HVR, da Silva AM, Lee PC, Brito BF, Silva AR, da Silva LDM, Comizzoli P. Influence of Microwave-Assisted Drying on Structural Integrity and Viability of Testicular Tissues from Adult and Prepubertal Domestic Cats. Biopreserv Biobank 2020; 18:415-424. [PMID: 32780644 DOI: 10.1089/bio.2020.0048] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Anhydrous preservation is a promising approach for storage of living biomaterials at nonfreezing temperatures. Using the domestic cat model, the objectives of this study were to characterize changes in histology, DNA integrity, and viability of testicular tissues from adult versus prepubertal individuals during microwave-assisted drying. Testes from each age group were cut into small pieces before reversible membrane permeabilization, exposure to trehalose, and microwave-assisted drying during different time periods. In Experiment 1, water content was monitored for up to 40 minutes of drying. Tissues from adult or prepubertal cats experienced similar decreases of water content during the first 10 minutes. Desiccation progressed slowly between 10 and 20 minutes and then remained stable. In Experiment 2, structural properties were explored at 5, 10, and 20 minutes of desiccation. Percentages of normal seminiferous tubules were lower after 20 minutes drying in adult (43%) than in prepubertal tissues (61%). At the same time point, the proportion of cell degeneration was higher in adult (53%) than prepubertal tissues (28%). Percentages of intact DNA in tissues remained above 85% regardless of the microwave time in both age groups. Lastly, adult and prepubertal tissues only lost 33% of viability in both age groups. Collective results demonstrated for the first time that normal morphology, incidence of degeneration, DNA integrity, and viability of testicular tissues remained at acceptable levels during microwave-assisted drying for 20 minutes. Overall, prepubertal testicular tissues appeared to be more resilient to microwave-assisted desiccations than adult tissues. Importantly, water loss in the presence of trehalose after 20 minutes of desiccation already is compatible with long-term storage of testicular tissues at temperatures above -20°C, which is one step closer to future storage at supra-zero temperatures.
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Affiliation(s)
| | - Andréia Maria da Silva
- Laboratory of Animal Germplasm Conservation, Federal Rural University of Semi-Arid, Mossoró, Brazil
| | - Pei-Chih Lee
- Smithsonian Conservation Biology Institute, National Zoological Park, Washington, District of Columbia, USA
| | - Bruna Farias Brito
- Laboratory of Carnivores Reproduction, State University of Ceará, Fortaleza, Brazil
| | | | | | - Pierre Comizzoli
- Smithsonian Conservation Biology Institute, National Zoological Park, Washington, District of Columbia, USA
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Pan L, Ni H, Jin W, Su X. Inhibition of ERK or Akt ameliorates intimal hyperplasia via up-regulation of Cx37 and down-regulation of Cx43 in balloon injury rat model. Cardiovasc Diagn Ther 2020; 10:658-666. [PMID: 32968622 DOI: 10.21037/cdt-20-345] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Background Connexins (Cxs) are reported to participate in atherosclerosis associated intimal hyperplasia (IH), while their function involved in the balloon injury (BI) induced IH and restenosis is less reported. Methods Forty-eight male Sprague-Dawley rats were randomly assigned to not injured (NI) group and BI group, which were further administrated with ERK-inhibitor U0216 and Akt-inhibitor MIK2206. Western blot and RT-PCR were utilized to detect the expression of Cx30, Cx37, Cx40, and Cx43 at 6 hours, 24 hours, 7 days, and 14 days post-surgery. H&E staining and related intima area, media area, and luminal area measurement were applied to indicate neointima formation and IH. ERK and Akt phosphorylation levels and proliferating cell nuclear antigen (PCNA) immunostaining were also detected. Results Among the four Cxs detected, Cx37 showed down-regulated, and Cx43 showed up-regulated temporal expression pattern in BI rats with confirmed neointima formation. Up-regulated p-ERK (P<0.01) and p-Akt (P<0.01) can be detected in BI rats compared with NI rats. Meanwhile, U0216 and MIK2206 can significantly reduce Cx43 expression and increase CX37 expression accompanied with reduced neointima formation and PCNA staining (P<0.05 or P<0.01) in BI rats. Conclusions ERK or Akt inhibition can alleviate BI-induced IH via up-regulation of Cx37 and down-regulation of Cx43.
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Affiliation(s)
- Lemen Pan
- Department of Vascular Surgery, the First Affiliated Hospital of Wenzhou Medical University, Wenzhou, China
| | - Haizhen Ni
- Department of Vascular Surgery, the First Affiliated Hospital of Wenzhou Medical University, Wenzhou, China
| | - Wenxu Jin
- Department of Vascular Surgery, the First Affiliated Hospital of Wenzhou Medical University, Wenzhou, China
| | - Xiang Su
- Department of Vascular Surgery, the First Affiliated Hospital of Wenzhou Medical University, Wenzhou, China
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Rozas-Villanueva MF, Casanello P, Retamal MA. Role of ROS/RNS in Preeclampsia: Are Connexins the Missing Piece? Int J Mol Sci 2020; 21:ijms21134698. [PMID: 32630161 PMCID: PMC7369723 DOI: 10.3390/ijms21134698] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2020] [Revised: 06/18/2020] [Accepted: 06/28/2020] [Indexed: 12/15/2022] Open
Abstract
Preeclampsia is a pregnancy complication that appears after 20 weeks of gestation and is characterized by hypertension and proteinuria, affecting both mother and offspring. The cellular and molecular mechanisms that cause the development of preeclampsia are poorly understood. An important feature of preeclampsia is an increase in oxygen and nitrogen derived free radicals (reactive oxygen species/reactive nitrogen species (ROS/RNS), which seem to be central players setting the development and progression of preeclampsia. Cell-to-cell communication may be disrupted as well. Connexins (Cxs), a family of transmembrane proteins that form hemichannels and gap junction channels (GJCs), are essential in paracrine and autocrine cell communication, allowing the movement of signaling molecules between cells as well as between the cytoplasm and the extracellular media. GJCs and hemichannels are fundamental for communication between endothelial and smooth muscle cells and, therefore, in the control of vascular contraction and relaxation. In systemic vasculature, the activity of GJCs and hemichannels is modulated by ROS and RNS. Cxs participate in the development of the placenta and are expressed in placental vasculature. However, it is unknown whether Cxs are modulated by ROS/RNS in the placenta, or whether this potential modulation contributes to the pathogenesis of preeclampsia. Our review addresses the possible role of Cxs in preeclampsia, and the plausible modulation of Cxs-formed channels by ROS and RNS. We suggest these factors may contribute to the development of preeclampsia.
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Affiliation(s)
- María F. Rozas-Villanueva
- Centro de Fisiología Celular e Integrativa, Facultad de Medicina Clínica Alemana, Universidad del Desarrollo, Santiago 7690000, Chile;
- Programa de Doctorado en Ciencias e Innovación en Medicina, Facultad de Medicina, Clínica Alemana Universidad del Desarrollo, Santiago 7690000, Chile
| | - Paola Casanello
- Department of Obstetrics, School of Medicine, Pontificia Universidad Católica de Chile, Santiago 7690000, Chile;
- Department of Neonatology, School of Medicine, Pontificia Universidad Católica de Chile, Santiago 7690000, Chile
| | - Mauricio A. Retamal
- Centro de Fisiología Celular e Integrativa, Facultad de Medicina Clínica Alemana, Universidad del Desarrollo, Santiago 7690000, Chile;
- Programa de Comunicación Celular de Cáncer, Facultad de Medicina Clínica Alemana, Universidad del Desarrollo, Santiago 7690000, Chile
- Correspondence:
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Mauro AK, Berdahl DM, Khurshid N, Clemente L, Ampey AC, Shah DM, Bird IM, Boeldt DS. Conjugated linoleic acid improves endothelial Ca2+ signaling by blocking growth factor and cytokine-mediated Cx43 phosphorylation. Mol Cell Endocrinol 2020; 510:110814. [PMID: 32259635 PMCID: PMC7253345 DOI: 10.1016/j.mce.2020.110814] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Revised: 03/13/2020] [Accepted: 03/31/2020] [Indexed: 12/21/2022]
Abstract
Sustained Ca2+ burst signaling is crucial for endothelial vasodilator production and is disrupted by growth factors and cytokines. Conjugated linoleic acid (CLA), a Src inhibitor in certain preparations, is generally regarded as safe during pregnancy by the FDA. Multiple CLA preparations; t10, c12 or c9, t11 CLA, or a 1:1 mixture of the two were administered before growth factor or cytokine treatment. Growth factors and cytokines caused a significant decrease in Ca2+ burst numbers in response to ATP stimulation. Both t10, c12 CLA and the 1:1 mixture rescued VEGF165 or TNFα inhibited Ca2+ bursts and correlated with Src-specific phosphorylation of connexin 43. VEGF165, TNFα, and IL-6 in combination at physiologic concentrations revealed IL-6 amplified the inhibitory effects of lower dose of VEGF165 and TNFα. Again, the 1:1 CLA mixture was most effective at rescue of function. Therefore, CLA formulations may be a promising treatment for endothelial dysfunction in diseases such as preeclampsia.
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Affiliation(s)
- Amanda K Mauro
- Perinatal Research Laboratories, Department of Obstetrics & Gynecology, University of Wisconsin - Madison, School Medicine and Public Health, Madison, WI, 53715, USA
| | - Danielle M Berdahl
- Perinatal Research Laboratories, Department of Obstetrics & Gynecology, University of Wisconsin - Madison, School Medicine and Public Health, Madison, WI, 53715, USA; Division of Maternal Fetal Medicine, Department of Obstetrics & Gynecology, University of Wisconsin - Madison, School Medicine and Public Health, Madison, WI, 53715, USA
| | - Nauman Khurshid
- Perinatal Research Laboratories, Department of Obstetrics & Gynecology, University of Wisconsin - Madison, School Medicine and Public Health, Madison, WI, 53715, USA; Division of Maternal Fetal Medicine, Department of Obstetrics & Gynecology, University of Wisconsin - Madison, School Medicine and Public Health, Madison, WI, 53715, USA
| | - Luca Clemente
- Perinatal Research Laboratories, Department of Obstetrics & Gynecology, University of Wisconsin - Madison, School Medicine and Public Health, Madison, WI, 53715, USA
| | - Amanda C Ampey
- Perinatal Research Laboratories, Department of Obstetrics & Gynecology, University of Wisconsin - Madison, School Medicine and Public Health, Madison, WI, 53715, USA
| | - Dinesh M Shah
- Division of Maternal Fetal Medicine, Department of Obstetrics & Gynecology, University of Wisconsin - Madison, School Medicine and Public Health, Madison, WI, 53715, USA
| | - Ian M Bird
- Perinatal Research Laboratories, Department of Obstetrics & Gynecology, University of Wisconsin - Madison, School Medicine and Public Health, Madison, WI, 53715, USA; Department of Pediatrics, University of Wisconsin - Madison, School Medicine and Public Health, Madison, WI, 53715, USA
| | - Derek S Boeldt
- Perinatal Research Laboratories, Department of Obstetrics & Gynecology, University of Wisconsin - Madison, School Medicine and Public Health, Madison, WI, 53715, USA.
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Zhou Y, Sun M, Tang Y, Chen Y, Zhu C, Yang Y, Wang C, Yu G, Tang Z. Responses of the proteome in testis of mice exposed chronically to environmentally relevant concentrations of Microcystin-LR. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2020; 187:109824. [PMID: 31654863 DOI: 10.1016/j.ecoenv.2019.109824] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2019] [Revised: 10/13/2019] [Accepted: 10/15/2019] [Indexed: 06/10/2023]
Abstract
Microcystin-LR (MC-LR), a widespread environmental contaminant, has been shown to have potent acute testicular toxicity. However, magnitudes of toxic effects, induced by MCs, depend on route and magnitude of exposure to the toxin. In the present study, male mice were orally exposed 1, 10 or 100 μg/L MC-LR for 90 or 180 days, and pathological approach and the isobaric tags for relative and absolute quantitation (iTRAQ)-based proteomics were employed with testes. Proteomics revealed that a number of differentially altered proteins may be involved in MC-LR-induced chronic testicular toxicity. The biological process analysis indicated the altered proteins played an important role in biological adhesion, cellular process, response to stimulus or rhythmic process. The cellular component analysis revealed that most of the proteins with altered expression associated with cell part, extracellular region, extracellular region part, membrane, membrane part, organelle or organelle part. The molecular function showed that these proteins were critical in molecular transducer activity. Integrity analyses provide first compelling evidence that MC-LR significantly cause dysfunction of blood-testis barrier (BTB) through affecting tight junctions and gap junctions. Moreover, phosphatidylinositol 3-kinase (PI3K)/AKT eventually contributed to injury result from chronic low-level MC-LR treatment. Identification of proteins in testis responsive to MC-LR provides insights into molecular mechanisms of chronic toxicity of MCs.
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Affiliation(s)
- Yuan Zhou
- Department of Biochemistry and Molecular Biology, Nanjing University of Chinese Medicine, Nanjing, 210023, Jiangsu, China
| | - Menghan Sun
- Department of Physiology, Nanjing University of Chinese Medicine, Nanjing, 210023, Jiangsu, China
| | - Ye Tang
- Department of Physiology, Nanjing University of Chinese Medicine, Nanjing, 210023, Jiangsu, China
| | - Yu Chen
- Research Center of Endocrine and Metabolic Diseases, Affiliated Hospital of Integrated Traditional Chinese and Western Medicine, Nanjing University of Chinese Medicine, Jiangsu Province Academy of Traditonal Chinese Medicine, Nanjing, 210023, Jiangsu, China
| | - Chan Zhu
- Department of Physiology, Nanjing University of Chinese Medicine, Nanjing, 210023, Jiangsu, China
| | - Yan Yang
- Department of Physiology, Nanjing University of Chinese Medicine, Nanjing, 210023, Jiangsu, China
| | - Changming Wang
- Department of Physiology, Nanjing University of Chinese Medicine, Nanjing, 210023, Jiangsu, China
| | - Guang Yu
- Department of Biochemistry and Molecular Biology, Nanjing University of Chinese Medicine, Nanjing, 210023, Jiangsu, China.
| | - Zongxiang Tang
- Department of Physiology, Nanjing University of Chinese Medicine, Nanjing, 210023, Jiangsu, China.
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Wu X, Zhang W, Li Y, Lin X. Structure and Function of Cochlear Gap Junctions and Implications for the Translation of Cochlear Gene Therapies. Front Cell Neurosci 2019; 13:529. [PMID: 31827424 PMCID: PMC6892400 DOI: 10.3389/fncel.2019.00529] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2019] [Accepted: 11/13/2019] [Indexed: 12/23/2022] Open
Abstract
Connexins (Cxs) are ubiquitous membrane proteins that are found throughout vertebrate organs, acting as building blocks of the gap junctions (GJs) known to play vital roles in the normal function of many organs. Mutations in Cx genes (particularly GJB2, which encodes Cx26) cause approximately half of all cases of congenital hearing loss in newborns. Great progress has been made in understanding GJ function and the molecular mechanisms for the role of Cxs in the cochlea. Data reveal that multiple types of Cxs work together to ensure normal development and function of the cochlea. These findings include many aspects not proposed in the classic K+ recycling theory, such as the formation of normal cochlear morphology (e.g., the opening of the tunnel of Corti), the fine-tuning of the innervation of nerve fibers to the hair cells (HCs), the maturation of the ribbon synapses, and the initiation of the endocochlear potential (EP). New data, especially those collected from targeted modification of major Cx genes in the mouse cochlea, have demonstrated that Cx26 plays an essential role in the postnatal maturation of the cochlea. Studies also show that Cx26 and Cx30 assume very different roles in the EP generation, given that only Cx26 is required for normal hearing. This article will review our current understanding of the molecular structure, cellular distribution, and major functions of cochlear GJs. Potential implications of the knowledge of cochlear GJs on the design and implementation of translational studies of cochlear gene therapies for Cx mutations are also discussed.
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Affiliation(s)
- Xuewen Wu
- Department of Otolaryngology, Head-Neck and Surgery, Xiangya Hospital of Central South University, Changsha, China
- Department of Otolaryngology, Emory University School of Medicine, Atlanta, GA, United States
| | - Wenjuan Zhang
- Department of Otolaryngology, Wuhan Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Yihui Li
- Department of Pharmacy, Changsha Hospital of Traditional Medicine, Changsha, China
| | - Xi Lin
- Department of Otolaryngology, Emory University School of Medicine, Atlanta, GA, United States
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Yeo JH, Choi EJ, Lee J. Inhibition of gap junctional intercellular communication by an anti-migraine agent, flunarizine. PLoS One 2019; 14:e0222326. [PMID: 31513635 PMCID: PMC6742374 DOI: 10.1371/journal.pone.0222326] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2019] [Accepted: 08/27/2019] [Indexed: 02/08/2023] Open
Abstract
Gap junctions (GJs), which consist of proteins called connexins, are intercellular channels that allow the passage of ions, second messengers, and small molecules. GJs and connexins are considered as emerging therapeutic targets for various diseases. Previously, we screened numerous compounds using our recently developed iodide yellow fluorescent protein gap junctional intercellular communication (I-YFP GJIC) assay and found that flunarizine (FNZ), used for migraine prophylaxis and as an add-on therapy for epilepsy, inhibits GJIC in LN215 human glioma cells. In this study, we confirmed that FNZ inhibits GJIC using the I-YFP GJIC assay. We demonstrated that FNZ inhibits GJ activities via a mechanism that is independent of calcium channels and dopaminergic D2, histaminergic H1, or 5-HT receptors. In addition, we showed that FNZ significantly increases connexin 43 (Cx43) phosphorylation on the cell surface, but does not alter the total amount of Cx43. The beneficial effects of FNZ on migraines and epilepsy might be related to GJ inhibition.
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Affiliation(s)
- Joo Hye Yeo
- College of Pharmacy, Yonsei Institute of Pharmaceutical Sciences, Yonsei University, Songdogwahak-ro, Yeonsu-gu, Korea
| | - Eun Ju Choi
- College of Pharmacy, Yonsei Institute of Pharmaceutical Sciences, Yonsei University, Songdogwahak-ro, Yeonsu-gu, Korea
| | - Jinu Lee
- College of Pharmacy, Yonsei Institute of Pharmaceutical Sciences, Yonsei University, Songdogwahak-ro, Yeonsu-gu, Korea
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28
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Zhou Y, Chen Y, Hu X, Guo J, Shi H, Yu G, Tang Z. Icariin attenuate microcystin-LR-induced gap junction injury in Sertoli cells through suppression of Akt pathways. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2019; 251:328-337. [PMID: 31091496 DOI: 10.1016/j.envpol.2019.04.114] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2018] [Revised: 03/27/2019] [Accepted: 04/24/2019] [Indexed: 06/09/2023]
Abstract
Microcystin-leucine-arginine (MC-LR) can cause male reproductive disorder. However, the underlying mechanism are not yet entirely elucidated. In this study, we aimed to investigated the effects of MC-LR on the integrity of blood-testis barrier (BTB) and the related molecular mechanisms. Both in vivo and in vitro experiments revealed that MC-LR caused disruption of BTB and gap junctions between Sertoli cells respectively, which was paralleled by the alteration of connexin43 (Cx43). Our data demonstrated that MC-LR decreased gap junction intercellular communication (GJIC) and impaired Cx43 expression by activating the phosphatidylinositol 3-kinase/Akt cascades. In addition, a possible protective effect of Icariin (ICA), a flavonoid isolated from Chinese medicinal herb, against MC-LR toxicity was investigated. The ICA prevented the degradation of GJIC and impairment of Cx43 induced by MC-LR via suppressing the Akt pathway. Together, our results confirmed that the expression of Cx43 induced by MC-LR was regulated in vivo and in vitro, which was involved in the destruction of BTB. Additionally, ICA seems to be able to mitigate the MC-LR toxic effects.
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Affiliation(s)
- Yuan Zhou
- School of Medicine and Life Sciences, Nanjing University of Chinese Medicine, Nanjing, 210023, Jiangsu, China
| | - Yu Chen
- Research Center of Endocrine and Metabolic Diseases, Affiliated Hospital of Integrated Traditional Chinese and Western Medicine, Nanjing University of Chinese Medicine, Jiangsu Province Academy of Traditional Chinese Medicine, Nanjing, 210023, Jiangsu, China
| | - Xueqin Hu
- School of Medicine and Life Sciences, Nanjing University of Chinese Medicine, Nanjing, 210023, Jiangsu, China
| | - Jun Guo
- School of Medicine and Life Sciences, Nanjing University of Chinese Medicine, Nanjing, 210023, Jiangsu, China
| | - Hao Shi
- School of Medicine and Life Sciences, Nanjing University of Chinese Medicine, Nanjing, 210023, Jiangsu, China
| | - Guang Yu
- School of Medicine and Life Sciences, Nanjing University of Chinese Medicine, Nanjing, 210023, Jiangsu, China
| | - Zongxiang Tang
- School of Medicine and Life Sciences, Nanjing University of Chinese Medicine, Nanjing, 210023, Jiangsu, China.
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Cx46 hemichannel modulation by nitric oxide: Role of the fourth transmembrane helix cysteine and its possible involvement in cataract formation. Nitric Oxide 2019; 86:54-62. [DOI: 10.1016/j.niox.2019.02.007] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2018] [Revised: 02/08/2019] [Accepted: 02/20/2019] [Indexed: 01/09/2023]
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30
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Pogoda K, Kameritsch P. Molecular regulation of myoendothelial gap junctions. Curr Opin Pharmacol 2019; 45:16-22. [DOI: 10.1016/j.coph.2019.03.006] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2018] [Revised: 02/14/2019] [Accepted: 03/15/2019] [Indexed: 11/16/2022]
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Kameritsch P, Kiemer F, Mannell H, Beck H, Pohl U, Pogoda K. PKA negatively modulates the migration enhancing effect of Connexin 43. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2019; 1866:828-838. [PMID: 30769008 DOI: 10.1016/j.bbamcr.2019.02.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2018] [Revised: 01/31/2019] [Accepted: 02/01/2019] [Indexed: 12/22/2022]
Abstract
Connexin 43 (Cx43) expression is associated with an increased cell migration and related changes of the actin cytoskeleton (enhanced filopodia formation). These effects are mediated by the C-terminal cytoplasmic part of Cx43 in a channel-independent manner. Since this part has been shown to interact with a variety of proteins and has multiple phosphorylation sites we analyzed here a potential role of the protein kinase A (PKA) for the Cx43 mediated increase in cell migration. Mutation of the PKA-phosphorylation site (substitution of three serines by alanine or glycine) resulted in a further increase in cell motility compared to wild-type Cx43, but with a loss of directionality. Likewise, cell motility was enhanced by PKA inhibition only in Cx43 expressing cells, while reduced in the presence of the PKA activator forskolin. In contrast, cell motility remained unaffected by stimulation with forskolin in cells expressing Cx43 with the mutated PKA phosphorylation site (Cx43-PKA) as well as in Cx-deficient cells. Moreover, PKA activation resulted in increased binding of PKA and VASP to Cx43 associated with an enhanced phosphorylation of VASP, an important regulatory protein of cell polarity and directed migration. Functionally, we could confirm these results in endothelial cells endogenously expressing Cx43. A Tat-Cx43 peptide containing the PKA phosphorylation site abolished the PKA dependent reduction in endothelial cell migration. Our results indicate that PKA dependent phosphorylation of Cx43 modulates cell motility and plays a pivotal role in regulating directed cell migration.
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Affiliation(s)
- Petra Kameritsch
- Walter Brendel Centre of Experimental Medicine, Ludwig-Maximilians-Universität München and Munich University Hospital, Großhaderner Str. 9, 82152 Planegg, Martinsried, Germany; DZHK (German Centre for Cardiovascular Research), partner site Munich Heart Alliance, Biedersteiner Str. 29, 80802 München, Germany.
| | - Felizitas Kiemer
- Walter Brendel Centre of Experimental Medicine, Ludwig-Maximilians-Universität München and Munich University Hospital, Großhaderner Str. 9, 82152 Planegg, Martinsried, Germany.
| | - Hanna Mannell
- Walter Brendel Centre of Experimental Medicine, Ludwig-Maximilians-Universität München and Munich University Hospital, Großhaderner Str. 9, 82152 Planegg, Martinsried, Germany.
| | - Heike Beck
- Walter Brendel Centre of Experimental Medicine, Ludwig-Maximilians-Universität München and Munich University Hospital, Großhaderner Str. 9, 82152 Planegg, Martinsried, Germany.
| | - Ulrich Pohl
- Walter Brendel Centre of Experimental Medicine, Ludwig-Maximilians-Universität München and Munich University Hospital, Großhaderner Str. 9, 82152 Planegg, Martinsried, Germany; DZHK (German Centre for Cardiovascular Research), partner site Munich Heart Alliance, Biedersteiner Str. 29, 80802 München, Germany; Munich Cluster for Systems Neurology (SyNergy), Feodor-Lynen-Str. 17, 81377 München, Germany.
| | - Kristin Pogoda
- Walter Brendel Centre of Experimental Medicine, Ludwig-Maximilians-Universität München and Munich University Hospital, Großhaderner Str. 9, 82152 Planegg, Martinsried, Germany; DZHK (German Centre for Cardiovascular Research), partner site Munich Heart Alliance, Biedersteiner Str. 29, 80802 München, Germany.
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Sinyuk M, Mulkearns-Hubert EE, Reizes O, Lathia J. Cancer Connectors: Connexins, Gap Junctions, and Communication. Front Oncol 2018; 8:646. [PMID: 30622930 PMCID: PMC6308394 DOI: 10.3389/fonc.2018.00646] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2018] [Accepted: 12/10/2018] [Indexed: 12/21/2022] Open
Abstract
Despite concerted clinical and research efforts, cancer is a leading cause of death worldwide. Surgery, radiation, and chemotherapy have remained the most common standard-of-care strategies against cancer for decades. However, the side effects of these therapies demonstrate the need to investigate adjuvant novel treatment modalities that minimize the harm caused to healthy cells and tissues. Normal and cancerous cells require communication amongst themselves and with their surroundings to proliferate and drive tumor growth. It is vital to understand how intercellular and external communication impacts tumor cell malignancy. To survive and grow, tumor cells, and their normal counterparts utilize cell junction molecules including gap junctions (GJs), tight junctions, and adherens junctions to provide contact points between neighboring cells and the extracellular matrix. GJs are specialized structures composed of a family of connexin proteins that allow the free diffusion of small molecules and ions directly from the cytoplasm of adjacent cells, without encountering the extracellular milieu, which enables rapid, and coordinated cellular responses to internal and external stimuli. Importantly, connexins perform three main cellular functions. They enable direct gap junction intercellular communication (GJIC) between cells, form hemichannels to allow cell communication with the extracellular environment, and serve as a site for protein-protein interactions to regulate signaling pathways. Connexins themselves have been found to promote tumor cell growth and invasiveness, contributing to the overall tumorigenicity and have emerged as attractive anti-tumor targets due to their functional diversity. However, connexins can also serve as tumor suppressors, and therefore, a complete understanding of the roles of the connexins and GJs in physiological and pathophysiological conditions is needed before connexin targeting strategies are applied. Here, we discuss how the three aspects of connexin function, namely GJIC, hemichannel formation, and connexin-protein interactions, function in normal cells, and contribute to tumor cell growth, proliferation, and death. Finally, we discuss the current state of anti-connexin therapies and speculate which role may be most amenable for the development of targeting strategies.
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Affiliation(s)
- Maksim Sinyuk
- Department of Biological, Geological, and Environmental Sciences, Cleveland State University, Cleveland, OH, United States
- Department of Cellular and Molecular Medicine, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, United States
| | - Erin E. Mulkearns-Hubert
- Department of Cellular and Molecular Medicine, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, United States
| | - Ofer Reizes
- Department of Biological, Geological, and Environmental Sciences, Cleveland State University, Cleveland, OH, United States
- Department of Cellular and Molecular Medicine, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, United States
- Cleveland Clinic Lerner College of Medicine, Cleveland Clinic, Cleveland, OH, United States
- Case Comprehensive Cancer Center, Case Western University, Cleveland, OH, United States
| | - Justin Lathia
- Department of Biological, Geological, and Environmental Sciences, Cleveland State University, Cleveland, OH, United States
- Department of Cellular and Molecular Medicine, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, United States
- Cleveland Clinic Lerner College of Medicine, Cleveland Clinic, Cleveland, OH, United States
- Case Comprehensive Cancer Center, Case Western University, Cleveland, OH, United States
- Rose Ella Burkhardt Brain Tumor and Neuro-Oncology Center, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, United States
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Beamish IV, Hinck L, Kennedy TE. Making Connections: Guidance Cues and Receptors at Nonneural Cell-Cell Junctions. Cold Spring Harb Perspect Biol 2018; 10:a029165. [PMID: 28847900 PMCID: PMC6211390 DOI: 10.1101/cshperspect.a029165] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
The field of axon guidance was revolutionized over the past three decades by the identification of highly conserved families of guidance cues and receptors. These proteins are essential for normal neural development and function, directing cell and axon migration, neuron-glial interactions, and synapse formation and plasticity. Many of these genes are also expressed outside the nervous system in which they influence cell migration, adhesion and proliferation. Because the nervous system develops from neural epithelium, it is perhaps not surprising that these guidance cues have significant nonneural roles in governing the specialized junctional connections between cells in polarized epithelia. The following review addresses roles for ephrins, semaphorins, netrins, slits and their receptors in regulating adherens, tight, and gap junctions in nonneural epithelia and endothelia.
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Affiliation(s)
- Ian V Beamish
- Department of Neurology & Neurosurgery, Montréal Neurological Institute, McGill University, Montréal, Quebec H3A 2B4, Canada
| | - Lindsay Hinck
- Department of Molecular, Cell and Developmental Biology, University of California, Santa Cruz, California 95064
| | - Timothy E Kennedy
- Department of Neurology & Neurosurgery, Montréal Neurological Institute, McGill University, Montréal, Quebec H3A 2B4, Canada
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Russo TA, Stoll D, Nader HB, Dreyfuss JL. Mechanical stretch implications for vascular endothelial cells: Altered extracellular matrix synthesis and remodeling in pathological conditions. Life Sci 2018; 213:214-225. [PMID: 30343127 DOI: 10.1016/j.lfs.2018.10.030] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2018] [Revised: 10/09/2018] [Accepted: 10/17/2018] [Indexed: 10/28/2022]
Abstract
AIMS Cardiovascular diseases such as hypertension, thrombosis and atherosclerosis are responses to mechanical forces applied to the endothelium. Endothelial cells respond to hemodynamic mechanical forces such as cellular mechanical stretching. We investigated the expression of glycosaminoglycans, proteoglycans and other extracellular matrix molecules in endothelial cells subjected to various mechanical stimuli. MAIN METHODS Endothelial cells were subjected to mechanical stretch in a vacuum system FlexCell™ to 5% (physiological condition) and 15% (pathological condition), for 4 h or 24 h. Culture plates not subjected to strain were used as controls. Subsequently, ECs were subjected to immunofluorescence, real-time PCR, PCR array, glycosaminoglycans biosynthesis using metabolic radiolabeling with 35S-sulfate and cell behavior assays (adhesion, migration and capillary tube formation). KEY FINDINGS Mechanical stretch induced changes in endothelial cell morphology. Pathological consequences of mechanical stretch included inhibited migration in 2-fold and capillary-like tube formation in 2-fold, when compared to physiological condition after 4 h of ECs exposure; it also reduced total sulfated glycosaminoglycans synthesis thereabout 1.5-fold. Pathological mechanical stretch conditions induced higher expression after 24 h of ECs exposure to mechanical stretch of syndecan-4 (3.5-fold), perlecan (9.1-fold), decorin (5.7-fold), adhesive proteins as fibronectin (5.6-fold) and collagen III α1 (2.2-fold) and growth factors, including VEGF-A (7.3-fold) and TGFβ-1 (14.6-fold) and TGFβ-3 (4.3-fold). SIGNIFICANCE Exposure of endothelial cells to mechanical stretch influenced remodeling of the extracellular matrix as well as cell-matrix interactions. These studies improve understanding of how vascular biology is affected by mechanical forces and how these molecules behave in cardiovascular diseases.
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Affiliation(s)
- T A Russo
- Department of Biochemistry, Molecular Biology Division, Carl Peter von Dietrich Laboratory, Escola Paulista de Medicina, Universidade Federal de São Paulo, Brazil
| | - D Stoll
- Department of Nephrology, Escola Paulista de Medicina, Universidade Federal de São Paulo, Brazil
| | - H B Nader
- Department of Biochemistry, Molecular Biology Division, Carl Peter von Dietrich Laboratory, Escola Paulista de Medicina, Universidade Federal de São Paulo, Brazil
| | - J L Dreyfuss
- Department of Biochemistry, Molecular Biology Division, Carl Peter von Dietrich Laboratory, Escola Paulista de Medicina, Universidade Federal de São Paulo, Brazil..
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Zhao J, Wu M, Chen S, Ji Z, Zheng X. TGF-β1 and connexin-43 expression in neurogenic bladder from rats with sacral spinal cord injury. Neurourol Urodyn 2018; 37:2502-2509. [PMID: 30070388 DOI: 10.1002/nau.23767] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2018] [Accepted: 06/19/2018] [Indexed: 12/22/2022]
Abstract
AIMS Sacral spinal cord injury (SCI) could induce underactive bladder (UAB). Malfunction of connexin 43 (CX43) regulated by TGF-β1 might involve in urinary bladder dysfunction. We studied the changes of CX43 and TGF-β1/Smad3 signaling in detrusor of neurogenic bladder (NB) in sacral SCI rats. METHODS Sacral SCI was produced by hemisection (SSCH) or transection (SSCT) of spinal cord between L4 and L5 in female Wistar rats. BBB scores, residual urine volume and bladder weight as well as characteristic cystometric parameters at 6th week were used to confirm the successful establishment of NB. Western blotting and qRT-PCR were used to exam the protein and mRNA expression levels of CX43, CX45, TGF-β1, and Smad3 in detrusor. RESULTS BBB scores were significantly decreased, with the lowest in SSCT rats (P < 0.01). The residual urine volume, mean bladder weight, and cystometric parameters were increased, with the highest in SSCT rats. CX43 and phospho-CX43 protein levels were significantly decreased, but those of TGF-β1, Smad3, and phospho-Smad3 were significantly increased. It was the protein and mRNA levels of CX43 but not those of CX45 which were decreased in negative accordance with those of TGF-β1 and Smad3. Those changes were more significant in SSCT than in SSCH rats. CONCLUSIONS This study indicates that voiding dysfunction is related to the decreased CX43 function in detrusor from NB. TGF-β1/Smad3 signaling might be involved in the down-regulation of CX43 in SCI rats. Early regulation of CX43 might be beneficial to patients with voiding dysfunction.
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Affiliation(s)
- Jimao Zhao
- Department of Urology, Beijing Friendship Hospital, Capital Medical University, Beijing, China
| | - Menghua Wu
- Department of Urology, Beijing Youan Hospital, Capital Medical University, Beijing, China
| | - Siyang Chen
- Department of Urology, Beijing Friendship Hospital, Capital Medical University, Beijing, China
| | - Zhengguo Ji
- Department of Urology, Beijing Friendship Hospital, Capital Medical University, Beijing, China
| | - Xin Zheng
- Department of Urology, Beijing Youan Hospital, Capital Medical University, Beijing, China
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36
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Kam CY, Dubash AD, Magistrati E, Polo S, Satchell KJF, Sheikh F, Lampe PD, Green KJ. Desmoplakin maintains gap junctions by inhibiting Ras/MAPK and lysosomal degradation of connexin-43. J Cell Biol 2018; 217:3219-3235. [PMID: 29959233 PMCID: PMC6123000 DOI: 10.1083/jcb.201710161] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2017] [Revised: 04/26/2018] [Accepted: 06/11/2018] [Indexed: 12/13/2022] Open
Abstract
Desmosomal mutations result in potentially deadly cardiocutaneous disease caused by electrical conduction defects and disruption of gap junctions. Kam et al. demonstrate a mechanism whereby loss of the intermediate filament anchoring protein desmoplakin stimulates Cx43 turnover by increasing K-Ras expression, marking Cx43 for lysosomal degradation through ERK1/2 phosphorylation. Desmoplakin (DP) is an obligate component of desmosomes, intercellular adhesive junctions that maintain the integrity of the epidermis and myocardium. Mutations in DP can cause cardiac and cutaneous disease, including arrhythmogenic cardiomyopathy (ACM), an inherited disorder that frequently results in deadly arrhythmias. Conduction defects in ACM are linked to the remodeling and functional interference with Cx43-based gap junctions that electrically and chemically couple cells. How DP loss impairs gap junctions is poorly understood. We show that DP prevents lysosomal-mediated degradation of Cx43. DP loss triggered robust activation of ERK1/2–MAPK and increased phosphorylation of S279/282 of Cx43, which signals clathrin-mediated internalization and subsequent lysosomal degradation of Cx43. RNA sequencing revealed Ras-GTPases as candidates for the aberrant activation of ERK1/2 upon loss of DP. Using a novel Ras inhibitor, Ras/Rap1-specific peptidase (RRSP), or K-Ras knockdown, we demonstrate restoration of Cx43 in DP-deficient cardiomyocytes. Collectively, our results reveal a novel mechanism for the regulation of the Cx43 life cycle by DP in cardiocutaneous models.
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Affiliation(s)
- Chen Yuan Kam
- Department of Pathology, Northwestern University Feinberg School of Medicine, Chicago, IL
| | - Adi D Dubash
- Department of Pathology, Northwestern University Feinberg School of Medicine, Chicago, IL
| | | | - Simona Polo
- Fondazione Istituto FIRC di Oncologia Molecolare, Milan, Italy.,Dipartimento di Oncologia ed Emato-oncologia, Universita' degli Studi di Milano, Milan, Italy
| | - Karla J F Satchell
- Department of Microbiology-Immunology, Northwestern University Feinberg School of Medicine, Chicago, IL.,Robert H. Lurie Comprehensive Cancer Center, Northwestern University, Chicago, IL
| | - Farah Sheikh
- Department of Medicine, University of California, San Diego, La Jolla, CA
| | - Paul D Lampe
- Translational Research Program, Public Health Sciences Division, Fred Hutchinson Research Center, Seattle, WA
| | - Kathleen J Green
- Department of Pathology, Northwestern University Feinberg School of Medicine, Chicago, IL .,Department of Dermatology, Northwestern University Feinberg School of Medicine, Chicago, IL.,Robert H. Lurie Comprehensive Cancer Center, Northwestern University, Chicago, IL
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Ek-Vitorín JF, Pontifex TK, Burt JM. Cx43 Channel Gating and Permeation: Multiple Phosphorylation-Dependent Roles of the Carboxyl Terminus. Int J Mol Sci 2018; 19:E1659. [PMID: 29867029 PMCID: PMC6032060 DOI: 10.3390/ijms19061659] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2018] [Revised: 05/22/2018] [Accepted: 05/31/2018] [Indexed: 12/18/2022] Open
Abstract
Connexin 43 (Cx43), a gap junction protein seemingly fit to support cardiac impulse propagation and synchronic contraction, is phosphorylated in normoxia by casein kinase 1 (CK1). However, during cardiac ischemia or pressure overload hypertrophy, this phosphorylation fades, Cx43 abundance decreases at intercalated disks and increases at myocytes' lateral borders, and the risk of arrhythmia rises. Studies in wild-type and transgenic mice indicate that enhanced CK1-phosphorylation of Cx43 protects from arrhythmia, while dephosphorylation precedes arrhythmia vulnerability. The mechanistic bases of these Cx43 (de)phosphoform-linked cardiac phenotypes are unknown. We used patch-clamp and dye injection techniques to study the channel function (gating, permeability) of Cx43 mutants wherein CK1-targeted serines were replaced by aspartate (Cx43-CK1-D) or alanine (Cx43-CK1-A) to emulate phosphorylation and dephosphorylation, respectively. Cx43-CK1-D, but not Cx43-CK1-A, displayed high Voltage-sensitivity and variable permselectivity. Both mutants showed multiple channel open states with overall increased conductivity, resistance to acidification-induced junctional uncoupling, and hemichannel openings in normal external calcium. Modest differences in the mutant channels' function and regulation imply the involvement of dissimilar structural conformations of the interacting domains of Cx43 in electrical and chemical gating that may contribute to the divergent phenotypes of CK1-(de)phospho-mimicking Cx43 transgenic mice and that may bear significance in arrhythmogenesis.
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Affiliation(s)
- José F Ek-Vitorín
- Department of Physiology, University of Arizona, P.O. Box 245051, Tucson, AZ 85724, USA.
| | - Tasha K Pontifex
- Department of Physiology, University of Arizona, P.O. Box 245051, Tucson, AZ 85724, USA.
| | - Janis M Burt
- Department of Physiology, University of Arizona, P.O. Box 245051, Tucson, AZ 85724, USA.
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García IE, Villanelo F, Contreras GF, Pupo A, Pinto BI, Contreras JE, Pérez-Acle T, Alvarez O, Latorre R, Martínez AD, González C. The syndromic deafness mutation G12R impairs fast and slow gating in Cx26 hemichannels. J Gen Physiol 2018; 150:697-711. [PMID: 29643172 PMCID: PMC5940247 DOI: 10.1085/jgp.201711782] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2017] [Revised: 11/13/2017] [Accepted: 03/21/2018] [Indexed: 12/27/2022] Open
Abstract
Mutations in connexin 26 hemichannels that cause syndromic deafness have a gain-of-function phenotype that is poorly understood. García et al. show that one such mutation impairs fast and slow gating in these hemichannels because of an interaction between the N terminus and intracellular loop. Mutations in connexin 26 (Cx26) hemichannels can lead to syndromic deafness that affects the cochlea and skin. These mutations lead to gain-of-function hemichannel phenotypes by unknown molecular mechanisms. In this study, we investigate the biophysical properties of the syndromic mutant Cx26G12R (G12R). Unlike wild-type Cx26, G12R macroscopic hemichannel currents do not saturate upon depolarization, and deactivation is faster during hyperpolarization, suggesting that these channels have impaired fast and slow gating. Single G12R hemichannels show a large increase in open probability, and transitions to the subconductance state are rare and short-lived, demonstrating an inoperative fast gating mechanism. Molecular dynamics simulations indicate that G12R causes a displacement of the N terminus toward the cytoplasm, favoring an interaction between R12 in the N terminus and R99 in the intracellular loop. Disruption of this interaction recovers the fast and slow voltage-dependent gating mechanisms. These results suggest that the mechanisms of fast and slow gating in connexin hemichannels are coupled and provide a molecular mechanism for the gain-of-function phenotype displayed by the syndromic G12R mutation.
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Affiliation(s)
- Isaac E García
- Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile.,Laboratory of Molecular Physiology and Biophysics, Facultad de Odontología, Universidad de Valparaíso, Valparaíso, Chile
| | - Felipe Villanelo
- Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile.,Computational Biology Laboratory, Fundación Ciencia & Vida, Santiago, Chile
| | - Gustavo F Contreras
- Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile
| | - Amaury Pupo
- Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile
| | - Bernardo I Pinto
- Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile
| | - Jorge E Contreras
- Department of Pharmacology, Physiology, and Neuroscience, New Jersey Medical School, Rutgers University, Newark, NJ
| | - Tomás Pérez-Acle
- Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile.,Computational Biology Laboratory, Fundación Ciencia & Vida, Santiago, Chile
| | - Osvaldo Alvarez
- Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile.,Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Santiago, Chile
| | - Ramon Latorre
- Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile
| | - Agustín D Martínez
- Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile
| | - Carlos González
- Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile
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Pecoraro M, Ciccarelli M, Fiordelisi A, Iaccarino G, Pinto A, Popolo A. Diazoxide Improves Mitochondrial Connexin 43 Expression in a Mouse Model of Doxorubicin-Induced Cardiotoxicity. Int J Mol Sci 2018. [PMID: 29518932 PMCID: PMC5877618 DOI: 10.3390/ijms19030757] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Doxorubicin (DOXO) administration induces alterations in Connexin 43 (Cx43) expression and localization, thus, inducing alterations in chemical and electrical signal transmission between cardiomyocytes and in intracellular calcium homeostasis even evident after a single administration. This study was designed to evaluate if Diazoxide (DZX), a specific opener of mitochondrial KATP channels widely used for its cardioprotective effects, can fight DOXO-induced cardiotoxicity in a short-time mouse model. DZX (20 mg/kg i.p.) was administered 30 min before DOXO (10 mg/kg i.p.) in C57BL/6j female mice for 1–3 or seven days once every other day. A recovery of cardiac parameters, evaluated by Echocardiography, were observed in DZX+DOXO co-treated mice. Western blot analysis performed on heart lysates showed an increase in sarco/endoplasmic reticulum Ca2+-ATPase (SERCAII) and a reduction in phospholamban (PLB) amounts in DZX+DOXO co-treated mice. A contemporary recovery of intracellular Ca2+-signal, detected spectrofluorometrically by means of FURA-2AM, was observed in these mice. Cx43 expression and localization, analyzed by Western blot and confirmed by immunofluorescence analysis, showed that DZX co-treatement increases Cx43 amount both on sarcoplasmic membrane and on mitochondria. In conclusion, our data demonstrate that, in a short-time mouse model of DOXO-induced cardiotoxicity, DZX exerts its cardioprotective effects also by enhancing the amount Cx43.
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Affiliation(s)
- Michela Pecoraro
- Department of Pharmacy, University of Salerno, Via Giovanni Paolo II, 84084 Fisciano, Italy.
| | - Michele Ciccarelli
- Department of Medicine and Surgery, University of Salerno, 84084 Baronissi, Italy.
| | - Antonella Fiordelisi
- Department of Advanced Biomedical Sciences, Federico II University, 80138 Naples, Italy.
| | - Guido Iaccarino
- Department of Medicine and Surgery, University of Salerno, 84084 Baronissi, Italy.
| | - Aldo Pinto
- Department of Pharmacy, University of Salerno, Via Giovanni Paolo II, 84084 Fisciano, Italy.
| | - Ada Popolo
- Department of Pharmacy, University of Salerno, Via Giovanni Paolo II, 84084 Fisciano, Italy.
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40
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Maarouf N, Sancho M, Fürstenhaupt T, Tran CH, Welsh DG. Structural analysis of endothelial projections from mesenteric arteries. Microcirculation 2018; 24. [PMID: 27809400 DOI: 10.1111/micc.12330] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2016] [Accepted: 10/31/2016] [Indexed: 01/31/2023]
Abstract
OBJECTIVE Endothelial and smooth muscle cells must communicate with one another to regulate arterial diameter. A key structure driving heterocellular communication is the endothelial projection, a thin extension that crosses the internal elastic lamina (IEL) making contact with smooth muscle. This study sought to define the precise structural composition of endothelial projections in the mesenteric circulation. METHODS Third- and fourth-order mesenteric arteries from hamster were prepared for electron microscopy. Electron tomographic approaches were used to generate 3-D compositional models of endothelial projections. RESULTS Endothelial projections were categorized based upon their proximity to smooth muscle or how many projections projected through an IEL hole. Irrespective of the initial categorization, endothelial projections were largely devoid of organelles except for sparse membranous structures observed near the tip, close to potential smooth muscle contact sites. Unexpectedly, it was the base of projections which were rich with organelles including the endoplasmic reticulum, ribosomes, vesicles, caveolae, and mitochondria. CONCLUSIONS Electron tomographic techniques suggest that the base of endothelial projections is likely a dynamic site for signal regulation and contractile control. As projections are largely devoid of membranous organelles, their principal function appears to ensure electrical contact between the two cell layers.
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Affiliation(s)
- Nadia Maarouf
- Department of Physiology and Pharmacology, Hotchkiss Brain Institute, Libin Cardiovascular Institute, University of Calgary, Calgary, AB, Canada
| | - Maria Sancho
- Department of Physiology and Pharmacology, Hotchkiss Brain Institute, Libin Cardiovascular Institute, University of Calgary, Calgary, AB, Canada.,Department of Physiology and Pharmacology, University of Western Ontario, London, ON, Canada
| | - Tobias Fürstenhaupt
- Department of Physiology and Pharmacology, Hotchkiss Brain Institute, Libin Cardiovascular Institute, University of Calgary, Calgary, AB, Canada
| | - Cam Ha Tran
- Department of Physiology and Pharmacology, Hotchkiss Brain Institute, Libin Cardiovascular Institute, University of Calgary, Calgary, AB, Canada
| | - Donald G Welsh
- Department of Physiology and Pharmacology, Hotchkiss Brain Institute, Libin Cardiovascular Institute, University of Calgary, Calgary, AB, Canada.,Department of Physiology and Pharmacology, University of Western Ontario, London, ON, Canada
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41
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Corticosterone impairs gap junctions in the prefrontal cortical and hippocampal astrocytes via different mechanisms. Neuropharmacology 2018; 131:20-30. [DOI: 10.1016/j.neuropharm.2017.12.003] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2017] [Revised: 11/28/2017] [Accepted: 12/03/2017] [Indexed: 01/20/2023]
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Protein Kinase C Enhances Electrical Synaptic Transmission by Acting on Junctional and Postsynaptic Ca 2+ Currents. J Neurosci 2018; 38:2796-2808. [PMID: 29440551 DOI: 10.1523/jneurosci.2619-17.2018] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2017] [Revised: 01/15/2018] [Accepted: 02/02/2018] [Indexed: 11/21/2022] Open
Abstract
By synchronizing neuronal activity, electrical transmission influences the coordination, pattern, and/or frequency of firing. In the hemaphroditic marine-snail, Aplysia calfornica, the neuroendocrine bag cell neurons use electrical synapses to synchronize a 30 min afterdischarge of action potentials for the release of reproductive hormone. During the afterdischarge, protein kinase C (PKC) is activated, although its impact on bag cell neuron electrical transmission is unknown. This was investigated here by monitoring electrical synapses between paired cultured bag cell neurons using dual whole-cell recording. Voltage clamp revealed a largely voltage-independent junctional current, which was enhanced by treating with a PKC activator, PMA, before recording. We also examined the transfer of presynaptic action potential-like waveforms (generated in voltage clamp) to the postsynaptic cell (measured in current clamp). For control pairs, the presynaptic spike-like waveforms mainly evoked electrotonic potentials; however, when PKC was triggered, these stimuli consistently produced postsynaptic action potentials. To assess whether this involved changes to postsynaptic responsiveness, single bag cell neurons were injected with junctional-like current mimicking that evoked by a presynaptic action potential. Unlike control neurons, which were less likely to spike, cells in PMA always fired action potentials to the junctional-like current. Furthermore, PKC activation increased a postsynaptic voltage-gated Ca2+ current, which was recruited even by modest depolarization associated with an electrotonic potential. Whereas PKC inhibits gap junctions in most systems, bag cell neurons are rather unique, as the kinase potentiates the electrical synapse; in turn, this synergizes with augmented postsynaptic Ca2+ current to promote synchronous firing.SIGNIFICANCE STATEMENT Electrical coupling is a fundamental form of communication. For the bag cell neurons of Aplysia, electrical synapses coordinate a prolonged burst of action potentials known as the afterdischarge. We looked at how protein kinase C, which is upregulated with the afterdischarge, influences information transfer across the synapse. The kinase activation increased junctional current, a remarkable finding given that this enzyme is largely considered inhibitory for gap junctions. There was also an augmentation in the ability of a presynaptic neuron to provoke postsynaptic action potentials. This increased excitability was, in part, due to enhanced postsynaptic voltage-dependent Ca2+ current. Thus, protein kinase C improves the fidelity of electrotonic transmission and promotes synchronous firing by modulating both junctional and membrane conductances.
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43
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Cerychova R, Pavlinkova G. HIF-1, Metabolism, and Diabetes in the Embryonic and Adult Heart. Front Endocrinol (Lausanne) 2018; 9:460. [PMID: 30158902 PMCID: PMC6104135 DOI: 10.3389/fendo.2018.00460] [Citation(s) in RCA: 78] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/10/2018] [Accepted: 07/26/2018] [Indexed: 12/12/2022] Open
Abstract
The heart is able to metabolize any substrate, depending on its availability, to satisfy its energy requirements. Under normal physiological conditions, about 95% of ATP is produced by oxidative phosphorylation and the rest by glycolysis. Cardiac metabolism undergoes reprograming in response to a variety of physiological and pathophysiological conditions. Hypoxia-inducible factor 1 (HIF-1) mediates the metabolic adaptation to hypoxia and ischemia, including the transition from oxidative to glycolytic metabolism. During embryonic development, HIF-1 protects the embryo from intrauterine hypoxia, its deletion as well as its forced expression are embryonically lethal. A decrease in HIF-1 activity is crucial during perinatal remodeling when the heart switches from anaerobic to aerobic metabolism. In the adult heart, HIF-1 protects against hypoxia, although its deletion in cardiomyocytes affects heart function even under normoxic conditions. Diabetes impairs HIF-1 activation and thus, compromises HIF-1 mediated responses under oxygen-limited conditions. Compromised HIF-1 signaling may contribute to the teratogenicity of maternal diabetes and diabetic cardiomyopathy in adults. In this review, we discuss the function of HIF-1 in the heart throughout development into adulthood, as well as the deregulation of HIF-1 signaling in diabetes and its effects on the embryonic and adult heart.
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Affiliation(s)
- Radka Cerychova
- Laboratory of Molecular Pathogenetics, Institute of Biotechnology of the Czech Academy of Sciences, Prague, Czechia
- Faculty of Science, Charles University, Prague, Czechia
| | - Gabriela Pavlinkova
- Laboratory of Molecular Pathogenetics, Institute of Biotechnology of the Czech Academy of Sciences, Prague, Czechia
- *Correspondence: Gabriela Pavlinkova
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44
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Redox-mediated regulation of connexin proteins; focus on nitric oxide. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2018; 1860:91-95. [DOI: 10.1016/j.bbamem.2017.10.006] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/08/2017] [Revised: 08/25/2017] [Accepted: 10/06/2017] [Indexed: 12/14/2022]
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45
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Connexin 43 and ATP-sensitive potassium channels crosstalk: a missing link in hypoxia/ischemia stress. Cell Tissue Res 2017; 371:213-222. [PMID: 29185069 DOI: 10.1007/s00441-017-2736-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2017] [Accepted: 11/06/2017] [Indexed: 12/28/2022]
Abstract
Connexin 43 (Cx43) is a gap junction protein expressed in various tissues and organs of vertebrates. Besides functioning as a gap junction, Cx43 also regulates diverse cellular processes like cell growth and differentiation, cell migration, cell survival, etc. Cx43 is critical for normal cardiac functioning and is therefore abundantly expressed in cardiomyocytes. On the other hand, ATP-sensitive potassium (KATP) channels are metabolic sensors converting metabolic changes into electrical activity. These channels are important in maintaining the neurotransmitter release, smooth muscle relaxation, cardiac action potential repolarization, normal physiology of cellular repolarization, insulin secretion and immune function. Cx43 and KATP channels are part of the same signaling pathway, regulating cell survival during stress conditions and ischemia/hypoxia preconditioning. However, the underlying molecular mechanism for their combined role in ischemia/hypoxia preconditioning is largely unknown. The current review focuses on understanding the molecular mechanism responsible for the coordinated role of Cx43 and KATP channel protein in protecting cardiomyocytes against ischemia/hypoxia stress.
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46
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Leybaert L, Lampe PD, Dhein S, Kwak BR, Ferdinandy P, Beyer EC, Laird DW, Naus CC, Green CR, Schulz R. Connexins in Cardiovascular and Neurovascular Health and Disease: Pharmacological Implications. Pharmacol Rev 2017; 69:396-478. [PMID: 28931622 PMCID: PMC5612248 DOI: 10.1124/pr.115.012062] [Citation(s) in RCA: 164] [Impact Index Per Article: 23.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Connexins are ubiquitous channel forming proteins that assemble as plasma membrane hemichannels and as intercellular gap junction channels that directly connect cells. In the heart, gap junction channels electrically connect myocytes and specialized conductive tissues to coordinate the atrial and ventricular contraction/relaxation cycles and pump function. In blood vessels, these channels facilitate long-distance endothelial cell communication, synchronize smooth muscle cell contraction, and support endothelial-smooth muscle cell communication. In the central nervous system they form cellular syncytia and coordinate neural function. Gap junction channels are normally open and hemichannels are normally closed, but pathologic conditions may restrict gap junction communication and promote hemichannel opening, thereby disturbing a delicate cellular communication balance. Until recently, most connexin-targeting agents exhibited little specificity and several off-target effects. Recent work with peptide-based approaches has demonstrated improved specificity and opened avenues for a more rational approach toward independently modulating the function of gap junctions and hemichannels. We here review the role of connexins and their channels in cardiovascular and neurovascular health and disease, focusing on crucial regulatory aspects and identification of potential targets to modify their function. We conclude that peptide-based investigations have raised several new opportunities for interfering with connexins and their channels that may soon allow preservation of gap junction communication, inhibition of hemichannel opening, and mitigation of inflammatory signaling.
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Affiliation(s)
- Luc Leybaert
- Physiology Group, Department of Basic Medical Sciences, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium (L.L.); Translational Research Program, Fred Hutchinson Cancer Research Center, Seattle, Washington (P.D.L.); Institute for Pharmacology, University of Leipzig, Leipzig, Germany (S.D.); Department of Pathology and Immunology, Department of Medical Specialization-Cardiology, University of Geneva, Geneva, Switzerland (B.R.K.); Department of Pharmacology and Pharmacotherapy, Semmelweis University, Budapest, Hungary (P.F.); Pharmahungary Group, Szeged, Hungary (P.F.); Department of Pediatrics, University of Chicago, Chicago, Illinois (E.C.B.); Department of Anatomy and Cell Biology, University of Western Ontario, Dental Science Building, London, Ontario, Canada (D.W.L.); Cellular and Physiological Sciences, Faculty of Medicine, The University of British Columbia, Vancouver, British Columbia, Canada (C.C.N.); Department of Ophthalmology and The New Zealand National Eye Centre, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand (C.R.G.); and Physiologisches Institut, Justus-Liebig-Universität Giessen, Giessen, Germany (R.S.)
| | - Paul D Lampe
- Physiology Group, Department of Basic Medical Sciences, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium (L.L.); Translational Research Program, Fred Hutchinson Cancer Research Center, Seattle, Washington (P.D.L.); Institute for Pharmacology, University of Leipzig, Leipzig, Germany (S.D.); Department of Pathology and Immunology, Department of Medical Specialization-Cardiology, University of Geneva, Geneva, Switzerland (B.R.K.); Department of Pharmacology and Pharmacotherapy, Semmelweis University, Budapest, Hungary (P.F.); Pharmahungary Group, Szeged, Hungary (P.F.); Department of Pediatrics, University of Chicago, Chicago, Illinois (E.C.B.); Department of Anatomy and Cell Biology, University of Western Ontario, Dental Science Building, London, Ontario, Canada (D.W.L.); Cellular and Physiological Sciences, Faculty of Medicine, The University of British Columbia, Vancouver, British Columbia, Canada (C.C.N.); Department of Ophthalmology and The New Zealand National Eye Centre, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand (C.R.G.); and Physiologisches Institut, Justus-Liebig-Universität Giessen, Giessen, Germany (R.S.)
| | - Stefan Dhein
- Physiology Group, Department of Basic Medical Sciences, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium (L.L.); Translational Research Program, Fred Hutchinson Cancer Research Center, Seattle, Washington (P.D.L.); Institute for Pharmacology, University of Leipzig, Leipzig, Germany (S.D.); Department of Pathology and Immunology, Department of Medical Specialization-Cardiology, University of Geneva, Geneva, Switzerland (B.R.K.); Department of Pharmacology and Pharmacotherapy, Semmelweis University, Budapest, Hungary (P.F.); Pharmahungary Group, Szeged, Hungary (P.F.); Department of Pediatrics, University of Chicago, Chicago, Illinois (E.C.B.); Department of Anatomy and Cell Biology, University of Western Ontario, Dental Science Building, London, Ontario, Canada (D.W.L.); Cellular and Physiological Sciences, Faculty of Medicine, The University of British Columbia, Vancouver, British Columbia, Canada (C.C.N.); Department of Ophthalmology and The New Zealand National Eye Centre, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand (C.R.G.); and Physiologisches Institut, Justus-Liebig-Universität Giessen, Giessen, Germany (R.S.)
| | - Brenda R Kwak
- Physiology Group, Department of Basic Medical Sciences, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium (L.L.); Translational Research Program, Fred Hutchinson Cancer Research Center, Seattle, Washington (P.D.L.); Institute for Pharmacology, University of Leipzig, Leipzig, Germany (S.D.); Department of Pathology and Immunology, Department of Medical Specialization-Cardiology, University of Geneva, Geneva, Switzerland (B.R.K.); Department of Pharmacology and Pharmacotherapy, Semmelweis University, Budapest, Hungary (P.F.); Pharmahungary Group, Szeged, Hungary (P.F.); Department of Pediatrics, University of Chicago, Chicago, Illinois (E.C.B.); Department of Anatomy and Cell Biology, University of Western Ontario, Dental Science Building, London, Ontario, Canada (D.W.L.); Cellular and Physiological Sciences, Faculty of Medicine, The University of British Columbia, Vancouver, British Columbia, Canada (C.C.N.); Department of Ophthalmology and The New Zealand National Eye Centre, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand (C.R.G.); and Physiologisches Institut, Justus-Liebig-Universität Giessen, Giessen, Germany (R.S.)
| | - Peter Ferdinandy
- Physiology Group, Department of Basic Medical Sciences, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium (L.L.); Translational Research Program, Fred Hutchinson Cancer Research Center, Seattle, Washington (P.D.L.); Institute for Pharmacology, University of Leipzig, Leipzig, Germany (S.D.); Department of Pathology and Immunology, Department of Medical Specialization-Cardiology, University of Geneva, Geneva, Switzerland (B.R.K.); Department of Pharmacology and Pharmacotherapy, Semmelweis University, Budapest, Hungary (P.F.); Pharmahungary Group, Szeged, Hungary (P.F.); Department of Pediatrics, University of Chicago, Chicago, Illinois (E.C.B.); Department of Anatomy and Cell Biology, University of Western Ontario, Dental Science Building, London, Ontario, Canada (D.W.L.); Cellular and Physiological Sciences, Faculty of Medicine, The University of British Columbia, Vancouver, British Columbia, Canada (C.C.N.); Department of Ophthalmology and The New Zealand National Eye Centre, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand (C.R.G.); and Physiologisches Institut, Justus-Liebig-Universität Giessen, Giessen, Germany (R.S.)
| | - Eric C Beyer
- Physiology Group, Department of Basic Medical Sciences, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium (L.L.); Translational Research Program, Fred Hutchinson Cancer Research Center, Seattle, Washington (P.D.L.); Institute for Pharmacology, University of Leipzig, Leipzig, Germany (S.D.); Department of Pathology and Immunology, Department of Medical Specialization-Cardiology, University of Geneva, Geneva, Switzerland (B.R.K.); Department of Pharmacology and Pharmacotherapy, Semmelweis University, Budapest, Hungary (P.F.); Pharmahungary Group, Szeged, Hungary (P.F.); Department of Pediatrics, University of Chicago, Chicago, Illinois (E.C.B.); Department of Anatomy and Cell Biology, University of Western Ontario, Dental Science Building, London, Ontario, Canada (D.W.L.); Cellular and Physiological Sciences, Faculty of Medicine, The University of British Columbia, Vancouver, British Columbia, Canada (C.C.N.); Department of Ophthalmology and The New Zealand National Eye Centre, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand (C.R.G.); and Physiologisches Institut, Justus-Liebig-Universität Giessen, Giessen, Germany (R.S.)
| | - Dale W Laird
- Physiology Group, Department of Basic Medical Sciences, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium (L.L.); Translational Research Program, Fred Hutchinson Cancer Research Center, Seattle, Washington (P.D.L.); Institute for Pharmacology, University of Leipzig, Leipzig, Germany (S.D.); Department of Pathology and Immunology, Department of Medical Specialization-Cardiology, University of Geneva, Geneva, Switzerland (B.R.K.); Department of Pharmacology and Pharmacotherapy, Semmelweis University, Budapest, Hungary (P.F.); Pharmahungary Group, Szeged, Hungary (P.F.); Department of Pediatrics, University of Chicago, Chicago, Illinois (E.C.B.); Department of Anatomy and Cell Biology, University of Western Ontario, Dental Science Building, London, Ontario, Canada (D.W.L.); Cellular and Physiological Sciences, Faculty of Medicine, The University of British Columbia, Vancouver, British Columbia, Canada (C.C.N.); Department of Ophthalmology and The New Zealand National Eye Centre, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand (C.R.G.); and Physiologisches Institut, Justus-Liebig-Universität Giessen, Giessen, Germany (R.S.)
| | - Christian C Naus
- Physiology Group, Department of Basic Medical Sciences, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium (L.L.); Translational Research Program, Fred Hutchinson Cancer Research Center, Seattle, Washington (P.D.L.); Institute for Pharmacology, University of Leipzig, Leipzig, Germany (S.D.); Department of Pathology and Immunology, Department of Medical Specialization-Cardiology, University of Geneva, Geneva, Switzerland (B.R.K.); Department of Pharmacology and Pharmacotherapy, Semmelweis University, Budapest, Hungary (P.F.); Pharmahungary Group, Szeged, Hungary (P.F.); Department of Pediatrics, University of Chicago, Chicago, Illinois (E.C.B.); Department of Anatomy and Cell Biology, University of Western Ontario, Dental Science Building, London, Ontario, Canada (D.W.L.); Cellular and Physiological Sciences, Faculty of Medicine, The University of British Columbia, Vancouver, British Columbia, Canada (C.C.N.); Department of Ophthalmology and The New Zealand National Eye Centre, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand (C.R.G.); and Physiologisches Institut, Justus-Liebig-Universität Giessen, Giessen, Germany (R.S.)
| | - Colin R Green
- Physiology Group, Department of Basic Medical Sciences, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium (L.L.); Translational Research Program, Fred Hutchinson Cancer Research Center, Seattle, Washington (P.D.L.); Institute for Pharmacology, University of Leipzig, Leipzig, Germany (S.D.); Department of Pathology and Immunology, Department of Medical Specialization-Cardiology, University of Geneva, Geneva, Switzerland (B.R.K.); Department of Pharmacology and Pharmacotherapy, Semmelweis University, Budapest, Hungary (P.F.); Pharmahungary Group, Szeged, Hungary (P.F.); Department of Pediatrics, University of Chicago, Chicago, Illinois (E.C.B.); Department of Anatomy and Cell Biology, University of Western Ontario, Dental Science Building, London, Ontario, Canada (D.W.L.); Cellular and Physiological Sciences, Faculty of Medicine, The University of British Columbia, Vancouver, British Columbia, Canada (C.C.N.); Department of Ophthalmology and The New Zealand National Eye Centre, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand (C.R.G.); and Physiologisches Institut, Justus-Liebig-Universität Giessen, Giessen, Germany (R.S.)
| | - Rainer Schulz
- Physiology Group, Department of Basic Medical Sciences, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium (L.L.); Translational Research Program, Fred Hutchinson Cancer Research Center, Seattle, Washington (P.D.L.); Institute for Pharmacology, University of Leipzig, Leipzig, Germany (S.D.); Department of Pathology and Immunology, Department of Medical Specialization-Cardiology, University of Geneva, Geneva, Switzerland (B.R.K.); Department of Pharmacology and Pharmacotherapy, Semmelweis University, Budapest, Hungary (P.F.); Pharmahungary Group, Szeged, Hungary (P.F.); Department of Pediatrics, University of Chicago, Chicago, Illinois (E.C.B.); Department of Anatomy and Cell Biology, University of Western Ontario, Dental Science Building, London, Ontario, Canada (D.W.L.); Cellular and Physiological Sciences, Faculty of Medicine, The University of British Columbia, Vancouver, British Columbia, Canada (C.C.N.); Department of Ophthalmology and The New Zealand National Eye Centre, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand (C.R.G.); and Physiologisches Institut, Justus-Liebig-Universität Giessen, Giessen, Germany (R.S.)
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Chen W, Feng J, Tong W. Phosphorylation of astrocytic connexin43 by ERK1/2 impairs blood-brain barrier in acute cerebral ischemia. Cell Biosci 2017; 7:43. [PMID: 28852468 PMCID: PMC5568205 DOI: 10.1186/s13578-017-0170-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2017] [Accepted: 08/10/2017] [Indexed: 12/19/2022] Open
Abstract
Background Connexins are a family of transmembrane proteins that form gap junctions, which are important for diffusion of cytosolic factors such as ions and second messenger signaling molecules. Our previous study has shown that Connexin40 (Cx40), one dominant connexin expressed in brain, was involved in brain injury. In this study, Cx43, another dominant connexin in brain, was investigated. Using bilateral common carotid artery occlusion-induced ischemia rat model, we tested the expression and phosphorylation level of Cx43 as well as heteromeric Cx40/Cx43 complex formation in brain after ischemia induction. We screened total 16 kinase inhibitors to identify the kinase for Cx43 phosphorylation and confirmed the result using siRNA targeting the specific kinase. Finally, we explored the role of the identified kinase in brain damage using in vivo rat model. Results We discovered that phosphorylation of Cx43 increased after ischemia. The formation of Cx40/Cx43 heteromeric complex on membrane also increased. Inhibition of ERK activity resulted in inhibition of Cx43 phosphorylation on astrocytes. In in vivo model, application of ERK inhibitor and siRNA prevented brain damage and protected blood–brain barrier integrity in rat. Conclusion Our study provides evidence that Cx43 phosphorylation by ERK is implicated in ischemia induced brain damage.
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Affiliation(s)
- Wei Chen
- The People's Hospital of Pu Dong New Area, 490 South Chuanhuan Road, Chuansha new town, Shanghai, 201299 People's Republic of China
| | - Jiugeng Feng
- Department of Neurosurgery, The First Affiliated Hospital of NanChang University, Yong Wai Zheng Street 17, Nanchang, 330006 China
| | - Wusong Tong
- The People's Hospital of Pu Dong New Area, 490 South Chuanhuan Road, Chuansha new town, Shanghai, 201299 People's Republic of China
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Gao Q, Katakowski M, Chen X, Li Y, Chopp M. Human Marrow Stromal Cells Enhance Connexin43 Gap Junction Intercellular Communication in Cultured Astrocytes. Cell Transplant 2017; 14:109-17. [PMID: 15881420 DOI: 10.3727/000000005783983205] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Human marrow stromal cells (hMSCs) provide functional benefit in rats subjected to stroke. Astrocytes are coupled into a cellular network via gap junction channels, predominantly composed of connexin-43 (Cx43) proteins. Astrocytes are believed to play a vital role in neuroprotection by providing energy substrates to neurons and by regulating the concentrations of K+ and neurotransmitters via gap junctions. We therefore investigated the effect of factors secreted by hMSCs on gap junction intercellular communication (GJIC), expression of Cx43, and phosphorylation of Cx43 in an astrocyte cell culture system. Exposing rat cortical astrocytes to various concentrations of hMSC conditioned medium, we demonstrate that hMSCs produce soluble factors that significantly increase astrocytic GJIC, measured by the scrape-loading dye transfer method. Immunohistochemistry and Western blot showed increased Cx43 expression concomitant with altered GJIC. As the PI3K/Akt signaling pathway has been demonstrated to alter gap junction expression and GJIC, we selectively blocked phosphoinositide 3-kinase (PI3K). Addition of the PI3K inhibitor LY294002 decreased GJIC and Cx43 expression in astrocytes. These inhibitory effects of LY294002 were countered by the addition of hMSC conditioned media. Furthermore, coculturing hMSCs with rat astrocytes increased astrocyte GJIC in a manner dependent upon the hMSC/astrocyte ratio. These findings demonstrate that hMSCs secrete soluble factors that increase GJIC of astrocytes through upregulation of Cx43, and indicate a mechanistic role for PI3K.
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Affiliation(s)
- Qi Gao
- Department of Neurology, Henry Ford Health Sciences Center, Detroit, MI 48202, USA
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Ampey BC, Ampey AC, Lopez GE, Bird IM, Magness RR. Cyclic Nucleotides Differentially Regulate Cx43 Gap Junction Function in Uterine Artery Endothelial Cells From Pregnant Ewes. Hypertension 2017; 70:401-411. [PMID: 28559397 PMCID: PMC5507815 DOI: 10.1161/hypertensionaha.117.09113] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2017] [Revised: 02/03/2017] [Accepted: 05/08/2017] [Indexed: 12/20/2022]
Abstract
Supplemental Digital Content is available in the text. Cell–cell communication is dependent on GJ (gap junction) proteins such as Cx43 (connexin 43). We previously demonstrated the importance of Cx43 function in establishing the enhanced pregnancy vasodilatory phenotype during pregnancy in uterine artery endothelial cells from pregnant (P-UAEC) ewes. Cx43 is regulated by elevating cAMP and PKA (protein kinase A)–dependent Cx43 S365 phosphorylation–associated trafficking and GJ open gating, which is opposed by PKC (protein kinase C)–dependent S368 phosphorylation-mediated GJ turnover and closed gating. However, the role of cyclic nucleotide-mediated signaling mechanisms that control Cx43 and GJ function in P-UAECs is unknown. We hypothesize that cAMP will mediate increases in S365 phosphorylation, thereby, enhancing GJ trafficking and open gating, while cGMP will stimulate S368, but not S365, phosphorylation to enhance GJ turnover and closed gating in P-UAECs. Treatment with 8-Bromo (8-Br)-cAMP signal significantly (P<0.05) increased nonphosphorylated S365 signal and total Cx43 phosphorylation, but not S368 phosphorylation, while 8-Br-cGMP significantly (P<0.05) increased Cx43 C-terminus-S365 signal, S368, and total Cx43 phosphorylation. Inhibition of PKA, but not PKG (protein kinase G), abrogated the 8-Br-cAMP–stimulated increase in nonphosphorylated S365 and total Cx43 phosphorylation and inhibited S368 below basal levels, whereas inhibition of PKG blocked (P<0.05) the 8-bromo-cGMP-stimulated rises in nonphosphorylated S365, total Cx43, and S368 phosphorylation levels in P-UAECs. Functional studies showed that 8-Br-cAMP increased dye transfer and sustained calcium bursts, while 8-Br-cGMP decreased both. Thus, in P-UAECs, only 8-Br-cAMP and not 8-Br-cGMP effectively enhances nonphosphorylated S365 and total Cx43 expression that correspondingly reduces S368 phosphorylation, allowing increased GJ communication. This provides new insights into the regulatory mechanisms behind Cx43 function and GJ communication.
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Affiliation(s)
- Bryan C Ampey
- From the Department of Obstetrics and Gynecology, Perinatal Research Labs University of Wisconsin, Madison (B.C.A., A.C.A., G.E.L., I.M.B., R.R.M.); and Department of Obstetrics and Gynecology, Perinatal Research Center Tampa, University of South Florida, (R.R.M.)
| | - Amanda C Ampey
- From the Department of Obstetrics and Gynecology, Perinatal Research Labs University of Wisconsin, Madison (B.C.A., A.C.A., G.E.L., I.M.B., R.R.M.); and Department of Obstetrics and Gynecology, Perinatal Research Center Tampa, University of South Florida, (R.R.M.)
| | - Gladys E Lopez
- From the Department of Obstetrics and Gynecology, Perinatal Research Labs University of Wisconsin, Madison (B.C.A., A.C.A., G.E.L., I.M.B., R.R.M.); and Department of Obstetrics and Gynecology, Perinatal Research Center Tampa, University of South Florida, (R.R.M.)
| | - Ian M Bird
- From the Department of Obstetrics and Gynecology, Perinatal Research Labs University of Wisconsin, Madison (B.C.A., A.C.A., G.E.L., I.M.B., R.R.M.); and Department of Obstetrics and Gynecology, Perinatal Research Center Tampa, University of South Florida, (R.R.M.)
| | - Ronald R Magness
- From the Department of Obstetrics and Gynecology, Perinatal Research Labs University of Wisconsin, Madison (B.C.A., A.C.A., G.E.L., I.M.B., R.R.M.); and Department of Obstetrics and Gynecology, Perinatal Research Center Tampa, University of South Florida, (R.R.M.).
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50
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Biswas J, Gupta S, Verma DK, Singh S. Streptozotocin alters glucose transport, connexin expression and endoplasmic reticulum functions in neurons and astrocytes. Neuroscience 2017; 356:151-166. [PMID: 28527957 DOI: 10.1016/j.neuroscience.2017.05.018] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2017] [Revised: 05/09/2017] [Accepted: 05/09/2017] [Indexed: 12/25/2022]
Abstract
The study was undertaken to explore the cell-specific streptozotocin (STZ)-induced mechanistic alterations. STZ-induced rodent model is a well-established experimental model of Alzheimer's disease (AD) and in our previous studies we have established it as an in vitro screening model of AD by employing N2A neuronal cells. Therefore, STZ was selected in the present study to understand the STZ-induced cell-specific alterations by utilizing neuronal N2A and astrocytes C6 cells. Both neuronal and astrocyte cells were treated with STZ at 10, 50, 100 and 1000μM concentrations for 48h. STZ exposure caused significant decline in cellular viability and augmented cytotoxicity of cells involving astrocytes activation. STZ treatment also disrupted the energy metabolism by altered glucose uptake and its transport in both cells as reflected with decreased expression of glucose transporters (GLUT) 1/3. The consequent decrease in ATP level and decreased mitochondrial membrane potential was also observed in both the cells. STZ caused increased intracellular calcium which could cause the initiation of endoplasmic reticulum (ER) stress. Significant upregulation of ER stress-related markers were observed in both cells after STZ treatment. The cellular communication of astrocytes and neurons was altered as reflected by increased expression of connexin 43 along with DNA fragmentation. STZ-induced apoptotic death was evaluated by elevated expression of caspase-3 and PI/Hoechst staining of cells. In conclusion, study showed that STZ exert alike biochemical alterations, ER stress and cellular apoptosis in both neuronal and astrocyte cells.
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Affiliation(s)
- Joyshree Biswas
- Toxicology Division, CSIR-Central Drug Research Institute, Lucknow 226031, India
| | - Sonam Gupta
- Toxicology Division, CSIR-Central Drug Research Institute, Lucknow 226031, India
| | - Dinesh Kumar Verma
- Toxicology Division, CSIR-Central Drug Research Institute, Lucknow 226031, India
| | - Sarika Singh
- Toxicology Division, CSIR-Central Drug Research Institute, Lucknow 226031, India.
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