Bromoenol lactone inhibits voltage-gated Ca 2+ and transient receptor potential canonical channels

Saikat Chakraborty, Zachary C. Berwick, Paula J. Bartlett, Sanjay Kumar, Andrew P. Thomas, Michael Sturek, Johnathan D. Tune, Alexander G. Obukhov

Research output: Contribution to journalArticle

15 Citations (Scopus)

Abstract

Circulating hormones stimulate the phospholipase Cβ (PLC)/Ca 2+ influx pathway to regulate numerous cell functions, including vascular tone. It was proposed previously that Ca 2+- independent phospholipase A 2 (iPLA 2)-dependent store-operated Ca 2+ influx channels mediate hormone-induced contractions in isolated arteries, because bromoenol lactone (BEL), a potent irreversible inhibitor of iPLA 2, inhibited such contractions. However, the effects of BEL on other channels implicated in mediating hormone-induced vessel contractions, specifically voltage-gated Ca 2+ (Ca V1.2) and transient receptor potential canonical (TRPC) channels, have not been defined clearly. Using isometric tension measurements, we found that thapsigargin-induced contractions were ~34% of those evoked by phenylephrine or KCl. BEL completely inhibited not only thapsigargin- but also phenylephrine- and KCl-induced ring contractions, suggesting that Ca V1.2 and receptor-operated TRPC channels also may be sensitive to BEL. Therefore, we investigated the effects of BEL on heterologously expressed Ca V1.2 and TRPC channels in human embryonic kidney cells, a model system that allows probing of individual protein function without interference from other signaling elements of native cells. We found that low micromolar concentrations of BEL inhibited Ca V1.2, TRPC5, TRPC6, and heteromeric TRPC1-TRPC5 channels in an iPLA 2-independent manner. BEL also attenuated PLC activity, suggesting that the compound may inhibit TRPC channel activity in part by interfering with an initial PLC-dependent step required for TRPC channel activation. Conversely, BEL did not affect endogenous voltage-gated K +channels in human embryonic kidney cells. Our findings support the hypothesis that iPLA 2-dependent store-operated Ca 2+influx channels and iPLA 2-independent hormone-operated TRPC channels can serve as smooth muscle depolarization triggers to activate Ca V1.2 channels and to regulate vascular tone.

Original languageEnglish (US)
Pages (from-to)329-340
Number of pages12
JournalJournal of Pharmacology and Experimental Therapeutics
Volume339
Issue number2
DOIs
StatePublished - Nov 1 2011

Fingerprint

Transient Receptor Potential Channels
Phospholipases A
Type C Phospholipases
Hormones
Thapsigargin
Phenylephrine
Blood Vessels
Kidney
Voltage-Gated Potassium Channels
6-(bromomethylene)tetrahydro-3-(1-naphthaleneyl)-2H-pyran-2-one
Smooth Muscle
Arteries

ASJC Scopus subject areas

  • Molecular Medicine
  • Pharmacology

Cite this

Bromoenol lactone inhibits voltage-gated Ca 2+ and transient receptor potential canonical channels. / Chakraborty, Saikat; Berwick, Zachary C.; Bartlett, Paula J.; Kumar, Sanjay; Thomas, Andrew P.; Sturek, Michael; Tune, Johnathan D.; Obukhov, Alexander G.

In: Journal of Pharmacology and Experimental Therapeutics, Vol. 339, No. 2, 01.11.2011, p. 329-340.

Research output: Contribution to journalArticle

Chakraborty, Saikat ; Berwick, Zachary C. ; Bartlett, Paula J. ; Kumar, Sanjay ; Thomas, Andrew P. ; Sturek, Michael ; Tune, Johnathan ; Obukhov, Alexander. / Bromoenol lactone inhibits voltage-gated Ca 2+ and transient receptor potential canonical channels. In: Journal of Pharmacology and Experimental Therapeutics. 2011 ; Vol. 339, No. 2. pp. 329-340.
@article{17eef937cdb549fabb51df4b64256ec5,
title = "Bromoenol lactone inhibits voltage-gated Ca 2+ and transient receptor potential canonical channels",
abstract = "Circulating hormones stimulate the phospholipase Cβ (PLC)/Ca 2+ influx pathway to regulate numerous cell functions, including vascular tone. It was proposed previously that Ca 2+- independent phospholipase A 2 (iPLA 2)-dependent store-operated Ca 2+ influx channels mediate hormone-induced contractions in isolated arteries, because bromoenol lactone (BEL), a potent irreversible inhibitor of iPLA 2, inhibited such contractions. However, the effects of BEL on other channels implicated in mediating hormone-induced vessel contractions, specifically voltage-gated Ca 2+ (Ca V1.2) and transient receptor potential canonical (TRPC) channels, have not been defined clearly. Using isometric tension measurements, we found that thapsigargin-induced contractions were ~34{\%} of those evoked by phenylephrine or KCl. BEL completely inhibited not only thapsigargin- but also phenylephrine- and KCl-induced ring contractions, suggesting that Ca V1.2 and receptor-operated TRPC channels also may be sensitive to BEL. Therefore, we investigated the effects of BEL on heterologously expressed Ca V1.2 and TRPC channels in human embryonic kidney cells, a model system that allows probing of individual protein function without interference from other signaling elements of native cells. We found that low micromolar concentrations of BEL inhibited Ca V1.2, TRPC5, TRPC6, and heteromeric TRPC1-TRPC5 channels in an iPLA 2-independent manner. BEL also attenuated PLC activity, suggesting that the compound may inhibit TRPC channel activity in part by interfering with an initial PLC-dependent step required for TRPC channel activation. Conversely, BEL did not affect endogenous voltage-gated K +channels in human embryonic kidney cells. Our findings support the hypothesis that iPLA 2-dependent store-operated Ca 2+influx channels and iPLA 2-independent hormone-operated TRPC channels can serve as smooth muscle depolarization triggers to activate Ca V1.2 channels and to regulate vascular tone.",
author = "Saikat Chakraborty and Berwick, {Zachary C.} and Bartlett, {Paula J.} and Sanjay Kumar and Thomas, {Andrew P.} and Michael Sturek and Tune, {Johnathan D.} and Obukhov, {Alexander G.}",
year = "2011",
month = "11",
day = "1",
doi = "10.1124/jpet.111.183673",
language = "English (US)",
volume = "339",
pages = "329--340",
journal = "Journal of Pharmacology and Experimental Therapeutics",
issn = "0022-3565",
publisher = "American Society for Pharmacology and Experimental Therapeutics",
number = "2",

}

TY - JOUR

T1 - Bromoenol lactone inhibits voltage-gated Ca 2+ and transient receptor potential canonical channels

AU - Chakraborty, Saikat

AU - Berwick, Zachary C.

AU - Bartlett, Paula J.

AU - Kumar, Sanjay

AU - Thomas, Andrew P.

AU - Sturek, Michael

AU - Tune, Johnathan D.

AU - Obukhov, Alexander G.

PY - 2011/11/1

Y1 - 2011/11/1

N2 - Circulating hormones stimulate the phospholipase Cβ (PLC)/Ca 2+ influx pathway to regulate numerous cell functions, including vascular tone. It was proposed previously that Ca 2+- independent phospholipase A 2 (iPLA 2)-dependent store-operated Ca 2+ influx channels mediate hormone-induced contractions in isolated arteries, because bromoenol lactone (BEL), a potent irreversible inhibitor of iPLA 2, inhibited such contractions. However, the effects of BEL on other channels implicated in mediating hormone-induced vessel contractions, specifically voltage-gated Ca 2+ (Ca V1.2) and transient receptor potential canonical (TRPC) channels, have not been defined clearly. Using isometric tension measurements, we found that thapsigargin-induced contractions were ~34% of those evoked by phenylephrine or KCl. BEL completely inhibited not only thapsigargin- but also phenylephrine- and KCl-induced ring contractions, suggesting that Ca V1.2 and receptor-operated TRPC channels also may be sensitive to BEL. Therefore, we investigated the effects of BEL on heterologously expressed Ca V1.2 and TRPC channels in human embryonic kidney cells, a model system that allows probing of individual protein function without interference from other signaling elements of native cells. We found that low micromolar concentrations of BEL inhibited Ca V1.2, TRPC5, TRPC6, and heteromeric TRPC1-TRPC5 channels in an iPLA 2-independent manner. BEL also attenuated PLC activity, suggesting that the compound may inhibit TRPC channel activity in part by interfering with an initial PLC-dependent step required for TRPC channel activation. Conversely, BEL did not affect endogenous voltage-gated K +channels in human embryonic kidney cells. Our findings support the hypothesis that iPLA 2-dependent store-operated Ca 2+influx channels and iPLA 2-independent hormone-operated TRPC channels can serve as smooth muscle depolarization triggers to activate Ca V1.2 channels and to regulate vascular tone.

AB - Circulating hormones stimulate the phospholipase Cβ (PLC)/Ca 2+ influx pathway to regulate numerous cell functions, including vascular tone. It was proposed previously that Ca 2+- independent phospholipase A 2 (iPLA 2)-dependent store-operated Ca 2+ influx channels mediate hormone-induced contractions in isolated arteries, because bromoenol lactone (BEL), a potent irreversible inhibitor of iPLA 2, inhibited such contractions. However, the effects of BEL on other channels implicated in mediating hormone-induced vessel contractions, specifically voltage-gated Ca 2+ (Ca V1.2) and transient receptor potential canonical (TRPC) channels, have not been defined clearly. Using isometric tension measurements, we found that thapsigargin-induced contractions were ~34% of those evoked by phenylephrine or KCl. BEL completely inhibited not only thapsigargin- but also phenylephrine- and KCl-induced ring contractions, suggesting that Ca V1.2 and receptor-operated TRPC channels also may be sensitive to BEL. Therefore, we investigated the effects of BEL on heterologously expressed Ca V1.2 and TRPC channels in human embryonic kidney cells, a model system that allows probing of individual protein function without interference from other signaling elements of native cells. We found that low micromolar concentrations of BEL inhibited Ca V1.2, TRPC5, TRPC6, and heteromeric TRPC1-TRPC5 channels in an iPLA 2-independent manner. BEL also attenuated PLC activity, suggesting that the compound may inhibit TRPC channel activity in part by interfering with an initial PLC-dependent step required for TRPC channel activation. Conversely, BEL did not affect endogenous voltage-gated K +channels in human embryonic kidney cells. Our findings support the hypothesis that iPLA 2-dependent store-operated Ca 2+influx channels and iPLA 2-independent hormone-operated TRPC channels can serve as smooth muscle depolarization triggers to activate Ca V1.2 channels and to regulate vascular tone.

UR - http://www.scopus.com/inward/record.url?scp=80054787641&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=80054787641&partnerID=8YFLogxK

U2 - 10.1124/jpet.111.183673

DO - 10.1124/jpet.111.183673

M3 - Article

C2 - 21795434

AN - SCOPUS:80054787641

VL - 339

SP - 329

EP - 340

JO - Journal of Pharmacology and Experimental Therapeutics

JF - Journal of Pharmacology and Experimental Therapeutics

SN - 0022-3565

IS - 2

ER -