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The Bioactive Phenolic Agents Diaryl Ether CVB2-61 and Diarylheptanoid CVB4-57 as Connexin Hemichannel Blockers. Pharmaceuticals (Basel) 2022; 15:ph15101173. [PMID: 36297285 PMCID: PMC9611528 DOI: 10.3390/ph15101173] [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: 08/02/2022] [Revised: 09/07/2022] [Accepted: 09/15/2022] [Indexed: 11/16/2022] Open
Abstract
Inflammation mediators enhance the activity of connexin (Cx) hemichannels, especially in the epithelial and endothelial tissues. As potential release routes for injury signals, such as (oligo)nucleotides, Cx hemichannels may contribute to long-lasting inflammation. Specific inhibition of Cx hemichannels may therefore be a mode of prevention and treatment of long-lasting, chronic sterile inflammation. The activity of Cx hemichannels was analysed in N2A and HeLa cells transfected with human Cx26 and Cx46 as well as in Calu-3 cells, using dye uptake as functional assay. Moreover, the possible impacts of the bioactive phenolic agents CVB2-61 and CVB4-57 on the barrier function of epithelial cells was analysed using Calu-3 cells. Both agents inhibited the dye uptake in N2A cells expressing Cx26 (>5 µM) and Cx46 (>20 µM). In Calu-3 cells, CVB2-61 and CVB4-57 reversibly inhibited the dye uptake at concentrations as low as 5 µM, without affecting the gap junction communication and barrier function, even at concentrations of 20 µM. While CVB2-61 or CVB4-57 maintained a reduced dye uptake in Calu-3 cells, an enhancement of the dye uptake in response to the stimulation of adenosine signalling was still observed after removal of the agents. The report shows that CVB2-61 and CVB4-57 reversibly block Cx hemichannels. Deciphering the mechanisms of the interactions of these agents with Cx hemichannels could allow further development of phenolic compounds to target Cx hemichannels for better and safer treatment of pathologies that involve Cx hemichannels.
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Güiza J, García A, Arriagada J, Gutiérrez C, González J, Márquez-Miranda V, Alegría-Arcos M, Duarte Y, Rojas M, González-Nilo F, Sáez JC, Vega JL. Unnexins: Homologs of innexin proteins in Trypanosomatidae parasites. J Cell Physiol 2021; 237:1547-1560. [PMID: 34779505 DOI: 10.1002/jcp.30626] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2021] [Revised: 10/05/2021] [Accepted: 10/26/2021] [Indexed: 11/07/2022]
Abstract
Large-pore channels, including those formed by connexin, pannexin, innexin proteins, are part of a broad family of plasma membrane channels found in vertebrates and invertebrates, which share topology features. Despite their relevance in parasitic diseases such as Chagas and malaria, it was unknown whether these large-pore channels are present in unicellular organisms. We identified 14 putative proteins in Trypanosomatidae parasites as presumptive homologs of innexin proteins. All proteins possess the canonical motif of the innexin family, a pentapeptide YYQWV, and 10 of them share a classical membrane topology of large-pore channels. A sequence similarity network analysis confirmed their closeness to innexin proteins. A bioinformatic model showed that a homolog of Trypanosoma cruzi (T. cruzi) could presumptively form a stable octamer channel with a highly positive electrostatic potential in the internal cavities and extracellular entrance due to the notable predominance of residues such as Arg or Lys. In vitro dye uptake assays showed that divalent cations-free solution increases YO-PRO-1 uptake and hyperosmotic stress increases DAPI uptake in epimastigotes of T. cruzi. Those effects were sensitive to probenecid. Furthermore, probenecid reduced the proliferation and transformation of T. cruzi. Moreover, probenecid or carbenoxolone increased the parasite sensitivity to antiparasitic drugs commonly used in therapy against Chagas. Our study suggests the existence of innexin homologs in unicellular organisms, which could be protein subunits of new large-pore channels in unicellular organisms.
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Affiliation(s)
- Juan Güiza
- Laboratory of Gap Junction Proteins and Parasitic Diseases (GaPaL), Instituto Antofagasta, Universidad de Antofagasta, Antofagasta, Chile
| | - Aníbal García
- Laboratory of Gap Junction Proteins and Parasitic Diseases (GaPaL), Instituto Antofagasta, Universidad de Antofagasta, Antofagasta, Chile
| | - Javiera Arriagada
- Laboratory of Gap Junction Proteins and Parasitic Diseases (GaPaL), Instituto Antofagasta, Universidad de Antofagasta, Antofagasta, Chile
| | - Camila Gutiérrez
- Laboratory of Gap Junction Proteins and Parasitic Diseases (GaPaL), Instituto Antofagasta, Universidad de Antofagasta, Antofagasta, Chile
| | - Jorge González
- Centro de Investigación en Inmunología y Biotecnología Biomédica de Antofagasta (CIIBBA), Universidad de Antofagasta, Antofagasta, Chile.,Molecular Parasitology Unit, Medical Technology Department, Faculty of Health Sciences, Universidad de Antofagasta, Antofagasta, Chile
| | | | | | - Yorley Duarte
- Center for Bioinformatics and Integrative Biology, Facultad de Ciencias de la Vida, Universidad Andres Bello, Santiago, Chile
| | - Maximiliano Rojas
- Center for Bioinformatics and Integrative Biology, Facultad de Ciencias de la Vida, Universidad Andres Bello, Santiago, Chile
| | - Fernando González-Nilo
- Center for Bioinformatics and Integrative Biology, Facultad de Ciencias de la Vida, Universidad Andres Bello, Santiago, Chile.,Instituto de Neurosciencias, Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile
| | - Juan C Sáez
- Instituto de Neurosciencias, Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile
| | - José L Vega
- Laboratory of Gap Junction Proteins and Parasitic Diseases (GaPaL), Instituto Antofagasta, Universidad de Antofagasta, Antofagasta, Chile.,Centro de Investigación en Inmunología y Biotecnología Biomédica de Antofagasta (CIIBBA), Universidad de Antofagasta, Antofagasta, Chile
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Schadzek P, Stahl Y, Preller M, Ngezahayo A. Analysis of the dominant mutation N188T of human connexin46 (hCx46) using concatenation and molecular dynamics simulation. FEBS Open Bio 2019; 9:840-850. [PMID: 31034164 PMCID: PMC6487695 DOI: 10.1002/2211-5463.12624] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2018] [Revised: 02/06/2019] [Accepted: 02/26/2019] [Indexed: 11/27/2022] Open
Abstract
Connexins (Cx) are proteins that form cell-to-cell gap junction channels. A mutation at position 188 in the second extracellular loop (E2) domain of hCx46 has been linked to an autosomal dominant zonular pulverulent cataract. As it is dominantly inherited, it is possible that the mutant variant affects the co-expressed wild-type Cx and/or its interaction with other cellular components. Here, we proposed to use concatenated hCx46wt-hCx46N188T and hCx46N188T-hCx46wt to analyze how hCx46N188T affected co-expressed hCx46wt to achieve a dominant inheritance. Heterodimer hCx46wt-hCx46N188T formed fewer gap junction plaques compared to homodimer hCx46wt-hCx46wt, while the hCx46N188T-hCx46N188T homodimer formed almost no gap junction plaques. Dye uptake experiments showed that hemichannels of concatenated variants were similar to hemichannels of monomers. Molecular dynamics simulations revealed that for docking, the N188 of a protomer was engaged in hydrogen bonds (HBs) with R180, N189, and D191 of the counterpart protomer of the adjacent hemichannel. T188 suppressed the formation of HBs between protomers. Molecular dynamics simulations of an equimolar hCx46wt/hCx46N188T gap junction channel revealed a reduced number of HBs between protomers, suggesting reduction of gap junction channels between lens fibers co-expressing the variants.
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Affiliation(s)
- Patrik Schadzek
- Institute of Cell Biology and BiophysicsDepartment of Cell Physiology and BiophysicsLeibniz University HannoverGermany
| | - Yannick Stahl
- Institute of Cell Biology and BiophysicsDepartment of Cell Physiology and BiophysicsLeibniz University HannoverGermany
| | - Matthias Preller
- Institute for Biophysical ChemistryHannover Medical School (MHH)Germany
- Centre for Structural Systems Biology, DESY‐CampusHamburgGermany
| | - Anaclet Ngezahayo
- Institute of Cell Biology and BiophysicsDepartment of Cell Physiology and BiophysicsLeibniz University HannoverGermany
- Center for System Neurosciences (ZSN)HannoverGermany
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An Overview of the Focus of the International Gap Junction Conference 2017 and Future Perspectives. Int J Mol Sci 2018; 19:ijms19092823. [PMID: 30231591 PMCID: PMC6164644 DOI: 10.3390/ijms19092823] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2018] [Accepted: 09/17/2018] [Indexed: 12/21/2022] Open
Abstract
This Special Issue relates to the 18th biannual International Gap Junction Conference (IGJC2017), held at the Crowne Plaza Hotel, Glasgow, U.K., from the 29 July⁻2 August 2017 [...].
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