K+ regulates Ca2+ to drive inflammasome signaling

Dynamic visualization of ion flux in live cells

J. R. Yaron, S. Gangaraju, M. Y. Rao, X. Kong, L. Zhang, F. Su, Y. Tian, H. L. Glenn, Deirdre Meldrum

Research output: Contribution to journalArticle

49 Citations (Scopus)

Abstract

P2X7 purinergic receptor engagement with extracellular ATP induces transmembrane potassium and calcium flux resulting in assembly of the NLRP3 inflammasome in LPS-primed macrophages. The role of potassium and calcium in inflammasome regulation is not well understood, largely due to limitations in existing methods for interrogating potassium in real time. The use of KS6, a novel sensor for selective and sensitive dynamic visualization of intracellular potassium flux in live cells, multiplexed with the intracellular calcium sensor Fluo-4, revealed a coordinated relationship between potassium and calcium. Interestingly, the mitochondrial potassium pool was mobilized in a P2X signaling, and ATP dose-dependent manner, suggesting a role for mitochondrial sensing of cytosolic ion perturbation. Through treatment with extracellular potassium we found that potassium efflux was necessary to permit sustained calcium entry, but not transient calcium flux from intracellular stores. Further, intracellular calcium chelation with BAPTA-AM indicated that P2X induced potassium depletion was independent of calcium mobilization. This evidence suggests that both potassium efflux and calcium influx are necessary for mitochondrial reactive oxygen generation upstream of NLRP3 inflammasome assembly and pyroptotic cell death. We propose a model wherein potassium efflux is necessary for calcium influx, resulting in mitochondrial reactive oxygen generation to trigger the NLRP3 inflammasome.

Original languageEnglish (US)
Article numbere1954
JournalCell Death and Disease
Volume6
Issue number10
DOIs
StatePublished - Oct 1 2015

Fingerprint

Inflammasomes
Potassium
Ions
Calcium
Adenosine Triphosphate
Purinergic P2X7 Receptors
Oxygen

ASJC Scopus subject areas

  • Cell Biology
  • Immunology
  • Cancer Research
  • Cellular and Molecular Neuroscience

Cite this

K+ regulates Ca2+ to drive inflammasome signaling : Dynamic visualization of ion flux in live cells. / Yaron, J. R.; Gangaraju, S.; Rao, M. Y.; Kong, X.; Zhang, L.; Su, F.; Tian, Y.; Glenn, H. L.; Meldrum, Deirdre.

In: Cell Death and Disease, Vol. 6, No. 10, e1954, 01.10.2015.

Research output: Contribution to journalArticle

Yaron, JR, Gangaraju, S, Rao, MY, Kong, X, Zhang, L, Su, F, Tian, Y, Glenn, HL & Meldrum, D 2015, 'K+ regulates Ca2+ to drive inflammasome signaling: Dynamic visualization of ion flux in live cells', Cell Death and Disease, vol. 6, no. 10, e1954. https://doi.org/10.1038/cddis.2015.277
Yaron, J. R. ; Gangaraju, S. ; Rao, M. Y. ; Kong, X. ; Zhang, L. ; Su, F. ; Tian, Y. ; Glenn, H. L. ; Meldrum, Deirdre. / K+ regulates Ca2+ to drive inflammasome signaling : Dynamic visualization of ion flux in live cells. In: Cell Death and Disease. 2015 ; Vol. 6, No. 10.
@article{eb8ae6a3cab04bcc923f92ed40c37f62,
title = "K+ regulates Ca2+ to drive inflammasome signaling: Dynamic visualization of ion flux in live cells",
abstract = "P2X7 purinergic receptor engagement with extracellular ATP induces transmembrane potassium and calcium flux resulting in assembly of the NLRP3 inflammasome in LPS-primed macrophages. The role of potassium and calcium in inflammasome regulation is not well understood, largely due to limitations in existing methods for interrogating potassium in real time. The use of KS6, a novel sensor for selective and sensitive dynamic visualization of intracellular potassium flux in live cells, multiplexed with the intracellular calcium sensor Fluo-4, revealed a coordinated relationship between potassium and calcium. Interestingly, the mitochondrial potassium pool was mobilized in a P2X signaling, and ATP dose-dependent manner, suggesting a role for mitochondrial sensing of cytosolic ion perturbation. Through treatment with extracellular potassium we found that potassium efflux was necessary to permit sustained calcium entry, but not transient calcium flux from intracellular stores. Further, intracellular calcium chelation with BAPTA-AM indicated that P2X induced potassium depletion was independent of calcium mobilization. This evidence suggests that both potassium efflux and calcium influx are necessary for mitochondrial reactive oxygen generation upstream of NLRP3 inflammasome assembly and pyroptotic cell death. We propose a model wherein potassium efflux is necessary for calcium influx, resulting in mitochondrial reactive oxygen generation to trigger the NLRP3 inflammasome.",
author = "Yaron, {J. R.} and S. Gangaraju and Rao, {M. Y.} and X. Kong and L. Zhang and F. Su and Y. Tian and Glenn, {H. L.} and Deirdre Meldrum",
year = "2015",
month = "10",
day = "1",
doi = "10.1038/cddis.2015.277",
language = "English (US)",
volume = "6",
journal = "Cell Death and Disease",
issn = "2041-4889",
publisher = "Nature Publishing Group",
number = "10",

}

TY - JOUR

T1 - K+ regulates Ca2+ to drive inflammasome signaling

T2 - Dynamic visualization of ion flux in live cells

AU - Yaron, J. R.

AU - Gangaraju, S.

AU - Rao, M. Y.

AU - Kong, X.

AU - Zhang, L.

AU - Su, F.

AU - Tian, Y.

AU - Glenn, H. L.

AU - Meldrum, Deirdre

PY - 2015/10/1

Y1 - 2015/10/1

N2 - P2X7 purinergic receptor engagement with extracellular ATP induces transmembrane potassium and calcium flux resulting in assembly of the NLRP3 inflammasome in LPS-primed macrophages. The role of potassium and calcium in inflammasome regulation is not well understood, largely due to limitations in existing methods for interrogating potassium in real time. The use of KS6, a novel sensor for selective and sensitive dynamic visualization of intracellular potassium flux in live cells, multiplexed with the intracellular calcium sensor Fluo-4, revealed a coordinated relationship between potassium and calcium. Interestingly, the mitochondrial potassium pool was mobilized in a P2X signaling, and ATP dose-dependent manner, suggesting a role for mitochondrial sensing of cytosolic ion perturbation. Through treatment with extracellular potassium we found that potassium efflux was necessary to permit sustained calcium entry, but not transient calcium flux from intracellular stores. Further, intracellular calcium chelation with BAPTA-AM indicated that P2X induced potassium depletion was independent of calcium mobilization. This evidence suggests that both potassium efflux and calcium influx are necessary for mitochondrial reactive oxygen generation upstream of NLRP3 inflammasome assembly and pyroptotic cell death. We propose a model wherein potassium efflux is necessary for calcium influx, resulting in mitochondrial reactive oxygen generation to trigger the NLRP3 inflammasome.

AB - P2X7 purinergic receptor engagement with extracellular ATP induces transmembrane potassium and calcium flux resulting in assembly of the NLRP3 inflammasome in LPS-primed macrophages. The role of potassium and calcium in inflammasome regulation is not well understood, largely due to limitations in existing methods for interrogating potassium in real time. The use of KS6, a novel sensor for selective and sensitive dynamic visualization of intracellular potassium flux in live cells, multiplexed with the intracellular calcium sensor Fluo-4, revealed a coordinated relationship between potassium and calcium. Interestingly, the mitochondrial potassium pool was mobilized in a P2X signaling, and ATP dose-dependent manner, suggesting a role for mitochondrial sensing of cytosolic ion perturbation. Through treatment with extracellular potassium we found that potassium efflux was necessary to permit sustained calcium entry, but not transient calcium flux from intracellular stores. Further, intracellular calcium chelation with BAPTA-AM indicated that P2X induced potassium depletion was independent of calcium mobilization. This evidence suggests that both potassium efflux and calcium influx are necessary for mitochondrial reactive oxygen generation upstream of NLRP3 inflammasome assembly and pyroptotic cell death. We propose a model wherein potassium efflux is necessary for calcium influx, resulting in mitochondrial reactive oxygen generation to trigger the NLRP3 inflammasome.

UR - http://www.scopus.com/inward/record.url?scp=84975292510&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84975292510&partnerID=8YFLogxK

U2 - 10.1038/cddis.2015.277

DO - 10.1038/cddis.2015.277

M3 - Article

VL - 6

JO - Cell Death and Disease

JF - Cell Death and Disease

SN - 2041-4889

IS - 10

M1 - e1954

ER -