Cell‐to‐cell communication in intact taste buds through ATP signalling from pannexin 1 gap junction hemichannels

Dando, Robin; Roper, Stephen D.

doi:10.1113/jphysiol.2009.180083

Cited by 104 publications

(117 citation statements)

References 57 publications

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“…Although it is widely accepted that ATP-permeable channels in type II cells are formed by Panx1, no direct evidence has been obtained so far in support of this idea but solely inhibitory effects of CBX on ATP release (Huang et al, 2007;Dando and Roper, 2009;Murata et al, 2010). The existing biophysical and pharmacological data on Panx1 channels were basically obtained in studies of recombinant Panx1 that was expressed mainly in Xenopus oocytes and HEK-293 cells (e.g.…”

Section: Atp Release In Taste Cells From Panx1-null Micementioning

confidence: 99%

“…We see no physiological reason in the usage of redundant afferent output, especially AP-driven, to finalize non-redundant taste transduction. The important issue however remains: if Panx1 is not involved, why CBX inhibits ATP secretion stimulated by tastants in taste cells (Huang et al, 2007;Dando and Roper, 2009;Murata et al, 2010)? Although at the moment we do not have clear answer, an interesting possibility comes from the recent study by Abascal and Zardoya (Abascal and Zardoya, 2012) on leucine-rich repeat-containing 8 (LRRC8) proteins.…”

Section: Atp Release In Taste Cells From Panx1-null Micementioning

confidence: 99%

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Dispensable ATP permeability of Pannexin 1 channels in a heterologous system and in mammalian taste cells

Romanov

Bystrova

Rogachevskaya

et al. 2012

Journal of Cell Science

154

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SummaryAfferent output in type II taste cells is mediated by ATP liberated through ion channels. It is widely accepted that pannexin 1 (Panx1) channels are responsible for ATP release in diverse cell types, including taste cells. While biophysical evidence implicates slow deactivation of ion channels following ATP release in taste cells, recombinant Panx1 activates and deactivates rapidly. This inconsistency could indicate that the cellular context specifies Panx1 functioning. We cloned Panx1 from murine taste tissue, and heterologously expressed it in three different cell lines: HEK-293, CHO and neuroblastoma SK-N-SH cells. In all three cell lines, Panx1 transfection yielded outwardly rectifying anion channels that exhibited fast gating and negligible permeability to anions exceeding 250 Da. Despite expression of Panx1, the host cells did not liberate ATP upon stimulation, making it unclear whether Panx1 is involved in taste-related ATP secretion. This issue was addressed using mice with genetic ablation of the Panx1 gene. The ATP-biosensor assay revealed that, in taste cells devoid of Panx1, ATP secretion was robust and apparently unchanged compared with the control. Our data suggest that Panx1 alone forms a channel that has insufficient permeability to ATP. Perhaps, a distinct subunit and/or a regulatory circuit that is absent in taste cells is required to enable a high ATP-permeability mode of a native Panx1-based channel.

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Section: Atp Release In Taste Cells From Panx1-null Micementioning

confidence: 99%

Section: Atp Release In Taste Cells From Panx1-null Micementioning

confidence: 99%

Dispensable ATP permeability of Pannexin 1 channels in a heterologous system and in mammalian taste cells

Romanov

Bystrova

Rogachevskaya

et al. 2012

Journal of Cell Science

154

View full text Add to dashboard Cite

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“…For example, a potent ectonucleotidase, nucleoside triphosphate diphosphohydrolase 2 (NTPDase2), is expressed on the surface of certain cells within the taste bud. NTPDase2 catabolizes the taste transmitter ATP and its metabolite ADP (2,11,47). Acetylcholinesterase is also present in taste tissue (29), perhaps related to ACh released during taste stimulation (10) or to its trophic properties.…”

Section: Resultsmentioning

confidence: 99%

A permeability barrier surrounds taste buds in lingual epithelia

Dando

Pereira

Kurian

et al. 2015

American Journal of Physiology-Cell Physiology

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Epithelial tissues are characterized by specialized cell-cell junctions, typically localized to the apical regions of cells. These junctions are formed by interacting membrane proteins and by cytoskeletal and extracellular matrix components. Within the lingual epithelium, tight junctions join the apical tips of the gustatory sensory cells in taste buds. These junctions constitute a selective barrier that limits penetration of chemosensory stimuli into taste buds (Michlig et al. J Comp Neurol 502: 1003–1011, 2007). We tested the ability of chemical compounds to permeate into sensory end organs in the lingual epithelium. Our findings reveal a robust barrier that surrounds the entire body of taste buds, not limited to the apical tight junctions. This barrier prevents penetration of many, but not all, compounds, whether they are applied topically, injected into the parenchyma of the tongue, or circulating in the blood supply, into taste buds. Enzymatic treatments indicate that this barrier likely includes glycosaminoglycans, as it was disrupted by chondroitinase but, less effectively, by proteases. The barrier surrounding taste buds could also be disrupted by brief treatment of lingual tissue samples with DMSO. Brief exposure of lingual slices to DMSO did not affect the ability of taste buds within the slice to respond to chemical stimulation. The existence of a highly impermeable barrier surrounding taste buds and methods to break through this barrier may be relevant to basic research and to clinical treatments of taste.

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“…Expression of Panx1 in xenopus oocytes revealed maxi anion currents upon membrane depolarization with KCl, and patch clamp studies demonstrated the permeability of these channels to ATP [154]. This observation has since prompted multiple studies investigating the role of Panx1 channels in ATP release from a number of cell types including: astrocytes, glial cells and neurons in the central nervous system [155][156][157][158][159][160], T-cells [161][162][163], airway epithelia [164,165], taste cells [166], keratinocytes [167], circulating erythrocytes [30,53], and vascular smooth muscle cells and endothelial cells [11,168]. While Panx1 channels constitute ATP release channels that function under physiological conditions, there have also been reports implicating these proteins in apoptosis and cell death [78], as well as in activation of T-cells during inflammation [161][162][163].…”

Section: Pannexin Channelsmentioning

confidence: 99%

“…Since their identification in 2000, Panx1 channels have been characterized as ATP release channels that may play a pivotal role in supporting purinergic signaling in a multitude of cell types [11,30,78,[161][162][163][164][165][166]205,[242][243][244]. Importantly, Panx1 channels mediate ATP release from vascular smooth muscle and endothelial cells [11,205], circulating erythrocytes [30,53], airway epithelial cells [164], astrocytes [158,159,244] and T-cells [161,162].…”

Section: Introductionmentioning

confidence: 99%

Function and Regulation of Pannexin 1 Channels in the Vascular Endothelium

Lohman¹

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The nucleotide adenosine 5'-triphosphate (ATP) has classically been considered the cell's primary energy currency; however, a novel role for ATP as an extracellular autocrine/paracrine signaling molecule has evolved over the past century. Purinergic signaling is now known to regulate a plethora of physiological and pathophysiological processes in almost every organ system. In the vasculature, ATP and its metabolites elicit dual control over blood vessel tone and tissue perfusion, and purinergic signaling events have been implicated in vascular pathologies including atherosclerosis and inflammation.While the importance of extracellular ATP in the vascular system is well recognized, the mechanism(s) mediating the regulated release of the purine from vascular cells are less well understood and are a key target of current investigation. One such ATP-liberation mechanism has been ascribed to the recently identified pannexin (Panx) channels, namely Panx1. Initially, we characterized the expression and localization profiles of Panx isoforms across the systemic vasculature, identifying predominant representation by the Panx1 isoform in both smooth muscle (SMC) and endothelial cells (EC) comprising the blood vessel wall, with more heterogeneous expression profiles observed in specialized vascular systems including the heart, lung and kidney. In particular, the Panx1 isoform is highly expressed in ECs regardless of blood vessel type or size, while Panx1 expression is limited to SMCs of small arteries and arterioles. Panx1 forms hexameric channels in the plasma membrane of ECs, functioning to release ATP in response to a number of stimuli. However, prolonged Panx1 channel activity is extremely detrimental to cell viability. Here we report a novel negative regulatory mechanism that may govern the activity of Panx1 channels in ECs, by which the bioactive gas nitric oxide (NO) covalently modifies two cysteine (Cys) residues in the channel by a process termed S- reinforce the dual effect of purines on peripheral resistance and blood pressure. Purinergic Control of Vascular InflammationWhile the foundation for purinergic control of vascular functions was initially characterized extensively in the context of vascular reactivity and overall blood flow and pressure regulation, it has become increasingly clear that extracellular ATP also plays important regulatory roles in the vascular inflammatory response. Vascular inflammation can be characterized as acute (physiological) or chronic (pathological) in nature.The acute vascular inflammatory response is an innate process of inflammatory cell homing to infected or damaged tissues resulting from integrated cross-talk between circulating leukocytes and the vascular endothelium, primarily at the level of postcapillary venules [61]. This process has been highly studied and is now known to occur in a step-wise manner beginning with local recruitment, rolling (fast and slow), adhesion and final extravasation into the surrounding tissue (reviewed in [62...

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Cell‐to‐cell communication in intact taste buds through ATP signalling from pannexin 1 gap junction hemichannels

Cited by 104 publications

References 57 publications

Dispensable ATP permeability of Pannexin 1 channels in a heterologous system and in mammalian taste cells

Dispensable ATP permeability of Pannexin 1 channels in a heterologous system and in mammalian taste cells

A permeability barrier surrounds taste buds in lingual epithelia

Function and Regulation of Pannexin 1 Channels in the Vascular Endothelium

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