Endogenous pannexin1 channels form functional intercellular cell–cell channels with characteristic voltage-dependent properties

Palacios-Prado, Nicolás; Soto, Paola; López, Ximena; Choi, Eun Ju; Márquez-Miranda, Valeria; Rojas, Mónica Maldonado; Duarte, Yorley; Lee, Jinu; González-Nilo, Fernando D.; Sáez, Juan C.

doi:10.1073/pnas.2202104119

Cited by 25 publications

(18 citation statements)

References 93 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Of note, recordings were conducted in symmetrical conditions, that is, using internal recording solutions (with high K + ) in both the cell attached patch and whole cell pipettes, arguing against an effect of high [K] o on inducing Px1 HC openings of large conductance (300-500 pS). Our data call for caution regarding the extrapolation of various Px1 HC configurations from dual whole cell recordings from pairs of electrically coupled cells via Px1 GJ channels (Palacios-Prado et al, 2022). In these recordings, a whole cell pipette monitors whole cell channel activity including that of Px1 GJ channels and unopposed Px1 HCs, and analysis of both unitary activities may be challenging.…”

Section: Discussionmentioning

confidence: 99%

“…For example, the unitary conductance of Cx43 HCs is about 220 pS, twice that of the gap junction channels, ~110 pS (Bukauskas et al, 2001; Bukauskas & Peracchia, 1997; Contreras et al, 2003). In contrast to Cx43 GJ, Px1 GJ channels may open with two main conductances, a prevalent voltage‐sensitive state of ~35 pS, and an infrequent and voltage‐insensitive state of ~170 pS (Palacios‐Prado et al, 2022). While early studies reported that when expressed exogenously in oocytes, human Px1 forms unopposed HCs that open with a maximum unitary conductance of ~500 pS (Bao et al, 2004; Qiu & Dahl, 2009), others have found that Px1 HCs have unitary conductances no larger than ~100 pS in excised outside out and inside out patches (Chiu et al, 2017; Ma et al, 2012), and there is still no general agreement on the single channel conductance of vertebrate unopposed Px1 HCs in the whole cell.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Single channel properties of pannexin‐1 and connexin‐43 hemichannels and P2X7 receptors in astrocytes cultured from rodent spinal cords

Garré

Bukauskas

Bennett

2022

Glia

View full text Add to dashboard Cite

Astrocytes express surface channels involved in purinergic signaling. Among these channels, pannexin-1 (Px1) and connexin-43 (Cx43) hemichannels (HCs) release ATP that acts directly, or through its derivatives, on neurons and glia via purinergic receptors. Although HCs are functional, that is, open and close under physiological and pathological conditions, single channel properties of Px1 HCs in astrocytes have not been defined. Here, we developed a dual voltage clamp technique in HeLa cells expressing human Px1-YFP, and then applied this system to rodent spinal astrocytes to compare their single channel properties with other surface channels, that is, Cx43 HCs and P2X7 receptors (P2X7Rs). Channels were recorded in cell attached patches and evoked with ramp cycles applied through another pipette in whole cell voltage clamp.The mean unitary conductances of Px1 HCs were comparable in HeLa Px1-YFP cells and spinal astrocytes, ~42 and ~48 pS, respectively. Based on their unitary conductance, voltage-dependence, and unitary activity after pharmacological and gene silencing, Px1 HCs in astrocytes could be distinguished from Cx43 HCs and P2X7Rs.Channel activity of Px1 HCs and P2X7Rs was greater than that of Cx43 HCs in control astrocytes during ramps. Unitary activity of Px1 HCs was decreased and that of Cx43HCs and P2X7Rs increased in astrocytes treated with fibroblast growth factor 1 (FGF-1). In summary, we resolved single channel properties of three different surface channels involved in purinergic signaling in spinal astrocytes, which were differentially modulated by FGF-1, a growth factor involved in neurodevelopment, inflammation and repair.

show abstract

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Single channel properties of pannexin‐1 and connexin‐43 hemichannels and P2X7 receptors in astrocytes cultured from rodent spinal cords

Garré

Bukauskas

Bennett

2022

Glia

View full text Add to dashboard Cite

show abstract

“…They have also been reported to contribute to the intracellular Ca 2+ homeostasis ( Shestopalov and Panchin, 2008 ). This single-membrane channel dogma was recently challenged by Palacios-Prado et al (2022) showing electrophysiological recordings of Panx1-mediated GJ-like direct cell-cell communication in transfected HeLa cells and in a human oligodendroglioma cell line naturally expressing Panx1. Whether primary cells and other cell lines show similar properties remains to be proven in the coming years.…”

Section: The Pannexin Protein Familymentioning

confidence: 99%

Pannexin1 channels—a potential therapeutic target in inflammation

Rusiecka

Tournier

Molica

et al. 2022

Front. Cell Dev. Biol.

View full text Add to dashboard Cite

An exaggerated inflammatory response is the hallmark of a plethora of disorders. ATP is a central signaling molecule that orchestrates the initiation and resolution of the inflammatory response by enhancing activation of the inflammasome, leukocyte recruitment and activation of T cells. ATP can be released from cells through pannexin (Panx) channels, a family of glycoproteins consisting of three members, Panx1, Panx2, and Panx3. Panx1 is ubiquitously expressed and forms heptameric channels in the plasma membrane mediating paracrine and autocrine signaling. Besides their involvement in the inflammatory response, Panx1 channels have been shown to contribute to different modes of cell death (i.e., pyroptosis, necrosis and apoptosis). Both genetic ablation and pharmacological inhibition of Panx1 channels decrease inflammation in vivo and contribute to a better outcome in several animal models of inflammatory disease involving various organs, including the brain, lung, kidney and heart. Up to date, several molecules have been identified to inhibit Panx1 channels, for instance probenecid (Pbn), mefloquine (Mfq), flufenamic acid (FFA), carbenoxolone (Cbx) or mimetic peptides like 10Panx1. Unfortunately, the vast majority of these compounds lack specificity and/or serum stability, which limits their application. The recent availability of detailed structural information on the Panx1 channel from cryo-electron microscopy studies may open up innovative approaches to acquire new classes of synthetic Panx1 channel blockers with high target specificity. Selective inhibition of Panx1 channels may not only limit acute inflammatory responses but may also prove useful in chronic inflammatory diseases, thereby improving human health. Here, we reviewed the current knowledge on the role of Panx1 in the initiation and resolution of the inflammatory response, we summarized the effects of Panx1 inhibition in inflammatory pathologies and recapitulate current Panx1 channel pharmacology with an outlook towards future approaches.

show abstract

“…However, when the N-linked glycosylation site is altered, preventing this post-translational modification, structural biology data suggests gap junction formation is possible [ 125 ]. One recent article argued that gap junction-forming innexins contain N-glycosylation sites at their extracellular loops and could form gap junction types of channels [ 126 ]. Using TC620 cells, an oligodendroglioma cell line, dye and electrical cell coupling were shown; the cell-to-cell coupling was reduced when Panx-1 was either knocked down by siRNA or inhibited by an inhibitory peptide [ 126 ].…”

Section: Hiv and Panx-1 Interactionsmentioning

confidence: 99%

“…One recent article argued that gap junction-forming innexins contain N-glycosylation sites at their extracellular loops and could form gap junction types of channels [ 126 ]. Using TC620 cells, an oligodendroglioma cell line, dye and electrical cell coupling were shown; the cell-to-cell coupling was reduced when Panx-1 was either knocked down by siRNA or inhibited by an inhibitory peptide [ 126 ]. However, Panx-1′s capacity to form gap junctions is still an open question.…”

Section: Hiv and Panx-1 Interactionsmentioning

confidence: 99%

The Role of Pannexin-1 Channels in HIV and NeuroHIV Pathogenesis

Hernandez

Eugenin

2022

Cells

View full text Add to dashboard Cite

The human immunodeficiency virus-1 (HIV) enters the brain shortly after infection, leading to long-term neurological complications in half of the HIV-infected population, even in the current anti-retroviral therapy (ART) era. Despite decades of research, no biomarkers can objectively measure and, more importantly, predict the onset of HIV-associated neurocognitive disorders. Several biomarkers have been proposed; however, most of them only reflect late events of neuronal damage. Our laboratory recently identified that ATP and PGE2, inflammatory molecules released through Pannexin-1 channels, are elevated in the serum of HIV-infected individuals compared to uninfected individuals and other inflammatory diseases. More importantly, high circulating ATP levels, but not PGE2, can predict a decline in cognition, suggesting that HIV-infected individuals have impaired ATP metabolism and associated signaling. We identified that Pannexin-1 channel opening contributes to the high serological ATP levels, and ATP in the circulation could be used as a biomarker of HIV-associated cognitive impairment. In addition, we believe that ATP is a major contributor to chronic inflammation in the HIV-infected population, even in the anti-retroviral era. Here, we discuss the mechanisms associated with Pannexin-1 channel opening within the circulation, as well as within the resident viral reservoirs, ATP dysregulation, and cognitive disease observed in the HIV-infected population.

show abstract

Endogenous pannexin1 channels form functional intercellular cell–cell channels with characteristic voltage-dependent properties

Cited by 25 publications

References 93 publications

Single channel properties of pannexin‐1 and connexin‐43 hemichannels and P2X7 receptors in astrocytes cultured from rodent spinal cords

Single channel properties of pannexin‐1 and connexin‐43 hemichannels and P2X7 receptors in astrocytes cultured from rodent spinal cords

Pannexin1 channels—a potential therapeutic target in inflammation

The Role of Pannexin-1 Channels in HIV and NeuroHIV Pathogenesis

Contact Info

Product

Resources

About