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Connexin46 in the nucleus of cancer cells: a possible role as transcription modulator
(Springer Science and Business Media LLC, 2025-03-27)
Ainoa Fernández-Olivares
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Viviana P Orellana
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Jesús Llanquinao
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NUÑEZ VASQUEZ, GONZALO ESTEBAN
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Pablo Pérez-Moreno
Scopus© Citations 1 10
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The role of astrocytes in depression, its prevention, and treatment by targeting astroglial gliotransmitter release
(2024)
Yorley Duarte
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Daisy Quintana-Donoso
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Rodrigo Moraga-Amaro
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Ivanka Dinamarca
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Yordan Lemunao
<jats:p>The role of ventral hippocampus (vHipp) astroglial gliotransmission in depression was studied using chronic restraint stress (CRS) and chronic unpredictable mild stress (CUMS) rodent models. CRS increased Cx43 hemichannel activity and extracellular glutamate levels in the vHipp and blocking astroglial Cx43 hemichannel-dependent gliotransmission during CRS prevented the development of depression and glutamate buildup. Moreover, the acute blockade of Cx43 hemichannels induced antidepressant effects in rats previously subjected to CRS or CUMS. This antidepressant effect was prevented by coinjection of glutamate and D-serine. Furthermore, Cx43 hemichannel blockade decreased postsynaptic NMDAR currents in vHipp slices in a glutamate and D-serine-dependent manner. Notably, chronic microinfusion of glutamate and D-serine, L-serine, or the NMDAR agonist NMDA, into the vHipp induced depressive-like symptoms in nonstressed rats. We also identified a small molecule, cacotheline, which blocks Cx43 hemichannels and its systemic administration induced rapid antidepressant effects, preventing stress-induced increases in astroglial Cx43 hemichannel activity and extracellular glutamate in the vHipp, without sedative or locomotor side effects. In conclusion, chronic stress increases Cx43 hemichannel-dependent release of glutamate and D-/L-serine from astrocytes in the vHipp, overactivating postsynaptic NMDARs and triggering depressive-like symptoms. This study highlights the critical role of astroglial gliotransmitter release in chronic stress-induced depression and suggests it can be used as a target for the prevention and treatment of depression.</jats:p>
Scopus© Citations 5 8
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Release of gliotransmitters through astroglial connexin 43 hemichannels is necessary for fear memory consolidation in the basolateral amygdala
(2012)
Jimmy Stehberg
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Rodrigo Moraga‐Amaro
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Christian Salazar
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Alvaro Becerra
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Cesar Echeverría
Scopus© Citations 201 1
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KI04 an Aminoglycosides-Derived Molecule Acts as an Inhibitor of Human Connexin46 Hemichannels Expressed in HeLa Cells
(2023)
Cheng-Wei T. Chang
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Naveena Poudyal
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Daniel A. Verdugo
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Francisca Peña
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Jimmy Stehberg
<jats:p>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.</jats:p>
2Scopus© Citations 3
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Peptides and peptide-derived molecules targeting the intracellular domains of Cx43: Gap junctions versus hemichannels
(2013)
Jegan Iyyathurai
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Catheleyne D'hondt
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Nan Wang
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Marijke De Bock
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Bernard Himpens
5Scopus© Citations 86
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Over-activated hemichannels: A possible therapeutic target for human diseases
(2021)
Mauricio A. Retamal
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Ainoa Fernandez-Olivares
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Jimmy Stehberg
Scopus© Citations 11 13
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Extracellular Cysteines Are Critical to Form Functional Cx46 Hemichannels
(2022)
Ainoa Fernández-Olivares
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Eduardo Durán-Jara
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Daniel A. Verdugo
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Mariana C. Fiori
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Guillermo A. Altenberg
<jats:p>Connexin (Cxs) hemichannels participate in several physiological and pathological processes, but the molecular mechanisms that control their gating remain elusive. We aimed at determining the role of extracellular cysteines (Cys) in the gating and function of Cx46 hemichannels. We studied Cx46 and mutated all of its extracellular Cys to alanine (Ala) (one at a time) and studied the effects of the Cys mutations on Cx46 expression, localization, and hemichannel activity. Wild-type Cx46 and Cys mutants were expressed at comparable levels, with similar cellular localization. However, functional experiments showed that hemichannels formed by the Cys mutants did not open either in response to membrane depolarization or removal of extracellular divalent cations. Molecular-dynamics simulations showed that Cys mutants may show a possible alteration in the electrostatic potential of the hemichannel pore and an altered disposition of important residues that could contribute to the selectivity and voltage dependency in the hemichannels. Replacement of extracellular Cys resulted in “permanently closed hemichannels”, which is congruent with the inhibition of the Cx46 hemichannel by lipid peroxides, through the oxidation of extracellular Cys. These results point to the modification of extracellular Cys as potential targets for the treatment of Cx46-hemichannel associated pathologies, such as cataracts and cancer, and may shed light into the gating mechanisms of other Cx hemichannels.</jats:p>
Scopus© Citations 6 2
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GABAergic Regulation of Astroglial Gliotransmission through Cx43 Hemichannels
(2022)
Ivanka Jiménez-Dinamarca
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Rachel Reyes-Lizana
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Yordan Lemunao-Inostroza
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Kevin Cárdenas
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Raimundo Castro-Lazo
<jats:p>Gamma-Aminobutyric acid (GABA) is the primary inhibitory neurotransmitter in the brain. It is produced by interneurons and recycled by astrocytes. In neurons, GABA activates the influx of Cl- via the GABAA receptor or efflux or K+ via the GABAB receptor, inducing hyperpolarization and synaptic inhibition. In astrocytes, the activation of both GABAA and GABAB receptors induces an increase in intracellular Ca2+ and the release of glutamate and ATP. Connexin 43 (Cx43) hemichannels are among the main Ca2+-dependent cellular mechanisms for the astroglial release of glutamate and ATP. However, no study has evaluated the effect of GABA on astroglial Cx43 hemichannel activity and Cx43 hemichannel-mediated gliotransmission. Here we assessed the effects of GABA on Cx43 hemichannel activity in DI NCT1 rat astrocytes and hippocampal brain slices. We found that GABA induces a Ca2+-dependent increase in Cx43 hemichannel activity in astrocytes mediated by the GABAA receptor, as it was blunted by the GABAA receptor antagonist bicuculline but unaffected by GABAB receptor antagonist CGP55845. Moreover, GABA induced the Cx43 hemichannel-dependent release of glutamate and ATP, which was also prevented by bicuculline, but unaffected by CGP. Gliotransmission in response to GABA was also unaffected by pannexin 1 channel blockade. These results are discussed in terms of the possible role of astroglial Cx43 hemichannel-mediated glutamate and ATP release in regulating the excitatory/inhibitory balance in the brain and their possible contribution to psychiatric disorders.</jats:p>
17Scopus© Citations 9
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Cx46 hemichannel modulation by nitric oxide: Role of the fourth transmembrane helix cysteine and its possible involvement in cataract formation
(2019)
RETAMAL LUCERO, MAURICIO ANTONIO
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Orellana Villena, Viviana Paulina
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Nicolás J. Arévalo
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Cristóbal G. Rojas
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Rodolfo J. Arjona
17 1Scopus© Citations 12
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4-Hydroxynonenal induces Cx46 hemichannel inhibition through its carbonylation
(2020)
Mauricio A. Retamal
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Mariana C. Fiori
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Ainoa Fernandez-Olivares
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Sergio Linsambarth
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Francisca Peña
Scopus© Citations 17 5

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