Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 2 de 2
Filtrar
Más filtros

Bases de datos
Tipo de estudio
Tipo del documento
Asunto de la revista
País de afiliación
Intervalo de año de publicación
1.
Proc Natl Acad Sci U S A ; 119(18): e2202104119, 2022 05 03.
Artículo en Inglés | MEDLINE | ID: mdl-35486697

RESUMEN

The occurrence of intercellular channels formed by pannexin1 has been challenged for more than a decade. Here, we provide an electrophysiological characterization of exogenous human pannexin1 (hPanx1) cell­cell channels expressed in HeLa cells knocked out for connexin45. The observed hPanx1 cell­cell channels show two phenotypes: O-state and S-state. The former displayed low transjunctional voltage (Vj) sensitivity and single-channel conductance of ∼175 pS, with a substate of ∼35 pS; the latter showed a peculiar dynamic asymmetry in Vj dependence and single-channel conductance identical to the substate conductance of the O-state. S-state hPanx1 cell­cell channels were also identified between TC620 cells, a human oligodendroglioma cell line that endogenously expresses hPanx1. In these cells, dye and electrical coupling increased with temperature and were strongly reduced after hPanx1 expression was knocked down by small interfering RNA or inhibited with Panx1 mimetic inhibitory peptide. Moreover, cell­cell coupling was augmented when hPanx1 levels were increased with a doxycycline-inducible expression system. Application of octanol, a connexin gap junction (GJ) channel inhibitor, was not sufficient to block electrical coupling between HeLa KO Cx45-hPanx1 or TC620 cell pairs. In silico studies suggest that several arginine residues inside the channel pore may be neutralized by hydrophobic interactions, allowing the passage of DAPI, consistent with dye coupling observed between TC620 cells. These findings demonstrate that endogenously expressed hPanx1 forms intercellular cell­cell channels and their unique properties resemble those described in innexin-based GJ channels. Since Panx1 is ubiquitously expressed, finding conditions to recognize Panx1 cell­cell channels in different cell types might require special attention.


Asunto(s)
Conexinas , Proteínas del Tejido Nervioso , Animales , Conexinas/metabolismo , Humanos , Canales Iónicos , Mamíferos/metabolismo , Proteínas del Tejido Nervioso/genética , Proteínas del Tejido Nervioso/metabolismo
2.
Glia ; 63(7): 1185-99, 2015 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-25731866

RESUMEN

The mechanism of secondary damage spread after brain trauma remains unsolved. In this work, we redirected the attention to astrocytic communication pathways. Using an in vitro trauma model that consists of a scratch injury applied to an astrocyte monolayer, we found a significant and transient induction of connexin43 (Cx43) hemichannel activity in regions distal from the injury, which was maximal ∼1 h after scratch. Two connexin hemichannel blockers, La(3+) and the peptide Gap26, abolished the increased activity, which was also absent in Cx43 KO astrocytes. In addition, the scratch-induced increase of hemichannel activity was prevented by inhibition of P2 purinergic receptors. Changes in hemichannel activity took place with a particular spatial distribution, with cells located at ∼17 mm away from the scratch presenting the highest activity (dye uptake). In contrast, the functional state of gap junction channels (dye coupling) was not significantly affected. Cx43 hemichannel activity was also enhanced by the acute extracellular application of 60 mM K(+) . The increase in hemichannel activity was associated with an increment in apoptotic cells at 24 h after scratch that was totally prevented by Gap26 peptide. These findings suggest that Cx43 hemichannels could be a new approach to prevent or reduce the secondary cell damage of brain trauma.


Asunto(s)
Astrocitos/metabolismo , Conexina 43/metabolismo , Animales , Apoptosis/efectos de los fármacos , Apoptosis/fisiología , Astrocitos/efectos de los fármacos , Lesiones Encefálicas , Membrana Celular/efectos de los fármacos , Membrana Celular/metabolismo , Células Cultivadas , Fármacos del Sistema Nervioso Central/farmacología , Conexina 43/antagonistas & inhibidores , Conexina 43/genética , Espacio Extracelular/efectos de los fármacos , Espacio Extracelular/metabolismo , Ratones Noqueados , Péptidos/administración & dosificación , Potasio/metabolismo , Antagonistas del Receptor Purinérgico P2/farmacología , Ratas Sprague-Dawley , Receptores Purinérgicos P2/metabolismo
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA