Isoform-specific modulation of coronary artery PKC by glucocorticoids

K. K. Maddali, Donna Hope Korzick, J. R. Turk, D. K. Bowles

Research output: Contribution to journalArticle

12 Citations (Scopus)

Abstract

Glucocorticoids (GC) exert diverse cellular effects in response to both acute and chronic stress, the functional consequences of which have been implicated in the development of cardiovascular pathology such as hypertension and atherosclerosis. However, the mechanisms by which GCs activate divergent signaling pathways are poorly understood. The present study examined the direct effects of natural (cortisol) and synthetic (dexamethasone) GCs on protein kinase C (PKC) isoform expression in coronary arteries. Porcine right coronary arteries were treated in vitro for 18 h in the presence and absence of either dexamethasone (10, 100, or 500 nM) or cortisol (50, 125, 250, or 500 nM). PKC isoform levels and subcellular distribution were determined by immmunoblotting of whole cell homogenates and immunocytofluorescence using PKC-α, -βII, -ε, -δ, and -ζ specific antibodies. Dexamethasone caused a ∼4-fold increase in PKC-α, a ∼2.5-fold increase in PKC-βII, and a 2-fold increase in PKC-ε (p < 0.05). In contrast, dexamethasone had no effect on PKC-δ or PKC- ζ levels. Dexamethasone also caused an increase in the activity of PKC-α (285%), -βII (170%), and -ε (210%). Cortisol produced similar effects on PKC isoform expression. Confocal microscopy revealed that while dexamethasone altered localization patterns for PKC-α, -βII, and -ε, no such effect was observed for PKC-δ or PKC-ζ. The stimulatory effects of dexamethasone and cortisol on coronary PKC levels and translocation were prevented by the GC receptor (GR) blocker, RU486. These results demonstrate, for the first time, that GCs modulate coronary PKC expression and subcellular distribution in an isoform-specific manner through a GR-dependent mechanism.

Original languageEnglish (US)
Pages (from-to)153-162
Number of pages10
JournalVascular Pharmacology
Volume42
Issue number4
DOIs
StatePublished - Jan 1 2005

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Protein Kinase C
Glucocorticoids
Coronary Vessels
Protein Isoforms
Dexamethasone
Hydrocortisone
Glucocorticoid Receptors
Confocal Microscopy
Atherosclerosis
Swine
Pathology
Hypertension

All Science Journal Classification (ASJC) codes

  • Physiology
  • Molecular Medicine
  • Pharmacology

Cite this

Maddali, K. K. ; Korzick, Donna Hope ; Turk, J. R. ; Bowles, D. K. / Isoform-specific modulation of coronary artery PKC by glucocorticoids. In: Vascular Pharmacology. 2005 ; Vol. 42, No. 4. pp. 153-162.
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Isoform-specific modulation of coronary artery PKC by glucocorticoids. / Maddali, K. K.; Korzick, Donna Hope; Turk, J. R.; Bowles, D. K.

In: Vascular Pharmacology, Vol. 42, No. 4, 01.01.2005, p. 153-162.

Research output: Contribution to journalArticle

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AU - Maddali, K. K.

AU - Korzick, Donna Hope

AU - Turk, J. R.

AU - Bowles, D. K.

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N2 - Glucocorticoids (GC) exert diverse cellular effects in response to both acute and chronic stress, the functional consequences of which have been implicated in the development of cardiovascular pathology such as hypertension and atherosclerosis. However, the mechanisms by which GCs activate divergent signaling pathways are poorly understood. The present study examined the direct effects of natural (cortisol) and synthetic (dexamethasone) GCs on protein kinase C (PKC) isoform expression in coronary arteries. Porcine right coronary arteries were treated in vitro for 18 h in the presence and absence of either dexamethasone (10, 100, or 500 nM) or cortisol (50, 125, 250, or 500 nM). PKC isoform levels and subcellular distribution were determined by immmunoblotting of whole cell homogenates and immunocytofluorescence using PKC-α, -βII, -ε, -δ, and -ζ specific antibodies. Dexamethasone caused a ∼4-fold increase in PKC-α, a ∼2.5-fold increase in PKC-βII, and a 2-fold increase in PKC-ε (p < 0.05). In contrast, dexamethasone had no effect on PKC-δ or PKC- ζ levels. Dexamethasone also caused an increase in the activity of PKC-α (285%), -βII (170%), and -ε (210%). Cortisol produced similar effects on PKC isoform expression. Confocal microscopy revealed that while dexamethasone altered localization patterns for PKC-α, -βII, and -ε, no such effect was observed for PKC-δ or PKC-ζ. The stimulatory effects of dexamethasone and cortisol on coronary PKC levels and translocation were prevented by the GC receptor (GR) blocker, RU486. These results demonstrate, for the first time, that GCs modulate coronary PKC expression and subcellular distribution in an isoform-specific manner through a GR-dependent mechanism.

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