Rapid, Nongenomic Effects of Aldosterone in the Heart Mediated by ε Protein Kinase C

Abstract Aldosterone elevates Na+/K+/2Cl− cotransporter activity in rabbit cardiomyocytes within 15 min, an effect blocked by K-canrenoate and thus putatively mineralocorticoid receptor mediated. Increased cotransporter activity raises intracellular [Na+] sufficient to produce a secondary increase in Na+-K+ pump activity; when this increase in intracellular [Na+] is prevented, a rapid effect of aldosterone to lower pump activity is seen. Addition of transcription inhibitor actinomycin D did not change basal or aldosterone-induced lowered pump activity, indicating a direct, nongenomic action of aldosterone. We examined a possible role for protein kinase C (PKC) in the rapid nongenomic effects of aldosterone. Single ventricular myocytes and pipette solutions containing 10 mm intracellular [Na+] were used in patch clamp studies to measure Na+-K+ pump activity. Aldosterone lowered pump current, an effect abolished by ε PKC (εPKC) inhibition but neither αPKC nor scrambled εPKC; addition of εPKC activator peptide mimicked the rapid aldosterone effect. In rabbits chronically infused with aldosterone, the lowered pump current in cardiomyocytes was acutely (≤15 min) restored by εPKC inhibition. These studies show that rapid effects of aldosterone on Na+-K+ pump activity are nongenomic and specifically εPKC mediated; in addition, such effects may be prolonged (7 d) and long-lived (∼4 h isolated cardiomyocyte preparation time). The rapid, prolonged, long-lived effects can be rapidly (≤15 min) reversed by εPKC blockade, suggesting a hitherto unrecognized complexity of aldosterone action in the heart and perhaps by extension other tissues.

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Protein kinase C modulates cytosolic free calcium by stimulating calcium pump activity in Jurkat T cells

Cell Calcium ◽

10.1016/0143-4160(95)90015-2 ◽

1995 ◽

Vol 18 (6) ◽

pp. 526-541 ◽

Cited By ~ 30

Author(s):

M. Balasubramanyam ◽

J.P. Gardner

Keyword(s):

T Cells ◽

Protein Kinase C ◽

Protein Kinase ◽

Calcium Pump ◽

Free Calcium ◽

Jurkat T Cells ◽

Cytosolic Free Calcium ◽

Kinase C ◽

Pump Activity

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Protein kinase C-ζ modulates thromboxane A2-mediated apoptosis in adult ventricular myocytes via Akt

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.2002.282.1.h320 ◽

2002 ◽

Vol 282 (1) ◽

pp. H320-H327 ◽

Cited By ~ 12

Author(s):

Yukitaka Shizukuda ◽

Peter M. Buttrick

Keyword(s):

Protein Kinase C ◽

Protein Kinase ◽

Cardiac Myocytes ◽

Ventricular Myocytes ◽

Kinase Assay ◽

Dependent Manner ◽

Adult Rat ◽

Kinase C ◽

Adult Cardiac Myocytes ◽

Pkc Ζ

We hypothesized that thromboxane A2 (TxA2) receptor stimulation directly induces apoptosis in adult cardiac myocytes. To investigate this, we exposed cultured adult rat ventricular myocytes (ARVM) to a TxA2 mimetic [1S-[1α,2α(Z),3β(1E,3S*),4α]]-7-[3-[3-hydroxy-4-(4-iodophenoxy)-1-butenyl]-7-oxabicyclo[2.2.1]hept-2-yl]-5-heptenoic acid (I-BOP) for 24 h. Stimulation with I-BOP induced apoptosis in a dose-dependent manner and was completely prevented by a TxA2 receptor antagonist, SQ-29548. We further investigated the role of protein kinase C (PKC) in this process. TxA2 stimulation resulted in membrane translocation of PKC-ζ but not PKC-α, -βII, -δ, and -ε at 3 min and 1 h. The activation of PKC-ζ by I-BOP was confirmed using an immune complex kinase assay. Treatment of ARVM with a cell-permeable PKC-ζ pseudosubstrate peptide (ζ-PS) significantly attenuated apoptosis by I-BOP. In addition, I-BOP treatment decreased baseline Akt activity and its decrease was reversed by treatment with ζ-PS. The inhibition of phosphatidylinositol 3-kinase upstream of Akt by wortmannin or LY-294002 abolished the antiapoptotic effect of ζ-PS. Therefore, our results suggest that the activation of PKC-ζ modulates TxA2 receptor-mediated apoptosis at least, in part, through Akt activity in adult cardiac myocytes.

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Ca2+ mobilization by extracellular ATP in rat cardiac myocytes: regulation by protein kinase C and A

AJP Cell Physiology ◽

10.1152/ajpcell.1992.263.5.c933 ◽

1992 ◽

Vol 263 (5) ◽

pp. C933-C940 ◽

Cited By ~ 22

Author(s):

J. S. Zheng ◽

A. Christie ◽

M. N. Levy ◽

A. Scarpa

Keyword(s):

Protein Kinase C ◽

Protein Kinase ◽

Ventricular Myocytes ◽

Cell Voltage ◽

Extracellular Atp ◽

Camp Level ◽

Intracellular Camp ◽

Beta Adrenergic ◽

Kinase C ◽

Integrated Response

Activation of protein kinase C (PKC) modulates the mobilization of intracellular Ca2+ induced by extracellular ATP in rat ventricular myocytes. Pretreatment of myocytes with PKC activators attenuated both the ATP-induced Ca2+ transient and the noradrenergic potentiation of the Ca2+ response. Various PKC activators decreased both the basal cAMP level and the cAMP levels that had been elevated by norepinephrine, forskolin, or 3-isobutyl-1-methylxanthine. The inhibitory effects of PKC activators were reversed by the PKC inhibitor staurosporine. The ATP-induced Ca2+ response is an integrated response resulting from ATP eliciting an inward cation current (IATP), cellular depolarization, Ca2+ influx through Ca2+ channels, and Ca2+ release from the sarcoplasmic reticulum. We used the whole cell voltage-clamp technique to investigate which steps of this integrated response are affected by PKC. PKC activators did not significantly affect the IATP. In contrast, PKC activators decreased the basal Ca2+ current (ICa) or Ba2+ current and the beta-adrenergic-stimulated ICa. These results suggest that PKC-induced suppression of the ATP-induced Ca2+ response and the beta-adrenergic-potentiated Ca2+ response is achieved at least partially by decreasing the intracellular cAMP level and ICa.

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Arachidonic acid enhances contraction and intracellular Ca2+ transients in individual rat ventricular myocytes

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.1997.272.1.h350 ◽

1997 ◽

Vol 272 (1) ◽

pp. H350-H359 ◽

Cited By ~ 7

Author(s):

D. S. Damron ◽

B. A. Summers

Keyword(s):

Arachidonic Acid ◽

Protein Kinase C ◽

Protein Kinase ◽

Cardiac Muscle ◽

Ventricular Myocytes ◽

Contractile Function ◽

Receptor Activation ◽

K Channels ◽

Rat Ventricular Myocytes ◽

Kinase C

Modulation of intracellular free Ca2+ concentration ([Ca2+]i) by inotropic stimuli alters contractility in cardiac muscle. Arachidonic acid (AA), a precursor for eicosanoid formation, is released in response to receptor activation and myocardial ischemia and has been demonstrated to alter K+ and Ca2+ channel activity. We investigated the effects of AA on contractility by simultaneously measuring [Ca2+]i and shortening in single field-stimulated rat ventricular myocytes. [Ca2+]i transients were measured using fura 2, and myocyte shortening was assessed using video edge detection. AA stimulated a doubling in the amplitude of the [Ca2+]i transient and a twofold increase in myocyte shortening. In addition, AA stimulated a 30% increase in the time to 50% diastolic [Ca2+]i and a 35% increase in the time to 50% relengthening. These effects of AA were mediated by AA itself (56 +/- 5%) and by cyclooxygenase metabolites. Pretreatment with the protein kinase C inhibitors staurosporine and chelerythrine nearly abolished (> 90% inhibition) these AA-induced effects. Inhibition of voltagegated K+ channels with 4-aminopyridine mimicked the effects of AA. Addition of AA to the 4-aminopyridine-treated myocyte had no additional effect on parameters of contractile function. These data indicate that AA alters the amplitude and duration of Ca2- transients and myocyte shortening via protein kinase C-dependent inhibition of voltage-gated K+ channels. Release of AA by phospholipases in response to receptor activation by endogenous mediators or pathological stimuli may be involved in mediating inotropic responses in cardiac muscle.

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Calmodulin kinase II and protein kinase C mediate the effect of increased intracellular calcium to augment late sodium current in rabbit ventricular myocytes

AJP Cell Physiology ◽

10.1152/ajpcell.00374.2011 ◽

2012 ◽

Vol 302 (8) ◽

pp. C1141-C1151 ◽

Cited By ~ 43

Author(s):

Jihua Ma ◽

Antao Luo ◽

Lin Wu ◽

Wei Wan ◽

Peihua Zhang ◽

...

Keyword(s):

Protein Kinase C ◽

Protein Kinase ◽

Ventricular Myocytes ◽

Sodium Current ◽

Dependent Manner ◽

Open Probability ◽

Late Sodium Current ◽

Kinase C ◽

Open Time ◽

Rabbit Ventricular Myocytes

An increase in intracellular Ca2+ concentration ([Ca2+]i) augments late sodium current ( INa.L) in cardiomyocytes. This study tests the hypothesis that both Ca2+-calmodulin-dependent protein kinase II (CaMKII) and protein kinase C (PKC) mediate the effect of increased [Ca2+]i to increase INa.L. Whole cell and open cell-attached patch clamp techniques were used to record INa.L in rabbit ventricular myocytes dialyzed with solutions containing various concentrations of [Ca2+]i. Dialysis of cells with [Ca2+]i from 0.1 to 0.3, 0.6, and 1.0 μM increased INa.L in a concentration-dependent manner from 0.221 ± 0.038 to 0.554 ± 0.045 pA/pF ( n = 10, P < 0.01) and was associated with an increase in mean Na+ channel open probability and prolongation of channel mean open-time ( n = 7, P < 0.01). In the presence of 0.6 μM [Ca2+]i, KN-93 (10 μM) and bisindolylmaleimide (BIM, 2 μM) decreased INa.L by 45.2 and 54.8%, respectively. The effects of KN-93 and autocamtide-2-related inhibitory peptide II (2 μM) were not different. A combination of KN-93 and BIM completely reversed the increase in INa.L as well as the Ca2+-induced changes in Na+ channel mean open probability and mean open-time induced by 0.6 μM [Ca2+]i. Phorbol myristoyl acetate increased INa.L in myocytes dialyzed with 0.1 μM [Ca2+]i; the effect was abolished by Gö-6976. In summary, both CaMKII and PKC are involved in [Ca2+]i-mediated augmentation of INa.L in ventricular myocytes. Inhibition of CaMKII and/or PKC pathways may be a therapeutic target to reduce myocardial dysfunction and cardiac arrhythmias caused by calcium overload.

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Enhancement of contraction and L-type Ca2+ current by murrayafoline-A via protein kinase C in rat ventricular myocytes

European Journal of Pharmacology ◽

10.1016/j.ejphar.2016.05.005 ◽

2016 ◽

Vol 784 ◽

pp. 33-41

Author(s):

Bojjibabu Chidipi ◽

Min-Jeong Son ◽

Joon-Chul Kim ◽

Jeong Hyun Lee ◽

Tran Quoc Toan ◽

...

Keyword(s):

Protein Kinase C ◽

Protein Kinase ◽

Ventricular Myocytes ◽

Rat Ventricular Myocytes ◽

Kinase C

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Regulation of Na+-K+ Pump Activity: Pathways Between Receptors and Effectors

Physiology ◽

10.1152/physiologyonline.1995.10.6.253 ◽

1995 ◽

Vol 10 (6) ◽

pp. 253-259 ◽

Cited By ~ 1

Author(s):

AM Bertorello ◽

AI Katz

Keyword(s):

Protein Kinase C ◽

Protein Kinase ◽

Short Term ◽

Dependent Protein Kinase ◽

Regulatory Pathways ◽

Kinase C ◽

Intracellular Signals ◽

Pump Activity ◽

Dependent Protein ◽

A Subunit

Short-term regulation of membrane Na+ -K+-ATPase activity is achieved by complex networks of receptor-mediated intracellular signals. Such regulatory pathways include activation of cyclic AMP-dependent protein kinase or protein kinase C and involve reversible phosphorylation of the catalytic (a) subunit of the enzyme directly, of additional mediators like eicosanoids and the actin cytoskeleton, or both.

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A new chapter in cardiac PKC signaling studies: searching for isoform-specific molecular targets. Focus on: “Isoenzyme-selective regulation of SERCA2 gene expression by protein kinase C in neonatal rat ventricular myocytes”

AJP Cell Physiology ◽

10.1152/ajpcell.00120.2003 ◽

2003 ◽

Vol 285 (1) ◽

pp. C19-C21 ◽

Cited By ~ 25

Author(s):

Peipei Ping

Keyword(s):

Gene Expression ◽

Protein Kinase C ◽

Protein Kinase ◽

Ventricular Myocytes ◽

Molecular Targets ◽

Neonatal Rat ◽

Rat Ventricular Myocytes ◽

Kinase C ◽

Pkc Signaling ◽

Neonatal Rat Ventricular Myocytes

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Aldosterone stimulates vacuolar H+-ATPase activity in renal acid-secretory intercalated cells mainly via a protein kinase C-dependent pathway

AJP Cell Physiology ◽

10.1152/ajpcell.00076.2011 ◽

2011 ◽

Vol 301 (5) ◽

pp. C1251-C1261 ◽

Cited By ~ 33

Author(s):

Christian Winter ◽

Nicole B. Kampik ◽

Luca Vedovelli ◽

Florina Rothenberger ◽

Teodor G. Păunescu ◽

...

Keyword(s):

Protein Kinase C ◽

Protein Kinase ◽

Atpase Activity ◽

Intracellular Signaling ◽

Collecting Duct ◽

Intercalated Cells ◽

Nongenomic Action ◽

Kinase C ◽

Urinary Acidification ◽

Stimulation Of

Urinary acidification in the collecting duct is mediated by the activity of H+-ATPases and is stimulated by various factors including angiotensin II and aldosterone. Classically, aldosterone effects are mediated via the mineralocorticoid receptor. Recently, we demonstrated a nongenomic stimulatory effect of aldosterone on H+-ATPase activity in acid-secretory intercalated cells of isolated mouse outer medullary collecting ducts (OMCD). Here we investigated the intracellular signaling cascade mediating this stimulatory effect. Aldosterone stimulated H+-ATPase activity in isolated mouse and human OMCDs. This effect was blocked by suramin, a general G protein inhibitor, and GP-2A, a specific Gαq inhibitor, whereas pertussis toxin was without effect. Inhibition of phospholipase C with U-73122, chelation of intracellular Ca2+ with BAPTA, and blockade of protein kinase C prevented the stimulation of H+-ATPases. Stimulation of PKC by DOG mimicked the effect of aldosterone on H+-ATPase activity. Similarly, aldosterone and DOG induced a rapid translocation of H+-ATPases to the luminal side of OMCD cells in vivo. In addition, PD098059, an inhibitor of ERK1/2 activation, blocked the aldosterone and DOG effects. Inhibition of PKA with H89 or KT2750 prevented and incubation with 8-bromoadenosine-cAMP mildly increased H+-ATPase activity. Thus, the nongenomic modulation of H+-ATPase activity in OMCD-intercalated cells by aldosterone involves several intracellular pathways and may be mediated by a Gαq protein-coupled receptor and PKC. PKA and cAMP appear to have a modulatory effect. The rapid nongenomic action of aldosterone may participate in the regulation of H+-ATPase activity and contribute to final urinary acidification.

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