Propofol Modulates Na+–Ca2+Exchange Activity via  Activation of Protein Kinase C in Diabetic Cardiomyocytes

2007 ◽  
Vol 106 (2) ◽  
pp. 302-311 ◽  
Author(s):  
Peter J. Wickley ◽  
Toshiya Shiga ◽  
Paul A. Murray ◽  
Derek S. Damron
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Sarcoplasmic Reticulum ◽  
Ventricular Myocytes ◽  
Cell Types ◽  
Intracellular Concentration ◽  
Diabetic Rat ◽  
Reverse Mode ◽  
Kinase C ◽  
Before And After

Background The authors' objective was to identify the role of the Na+-Ca2+ exchanger (NCX) in mediating the contractile dysfunction observed in diabetic cardiomyocytes before and after exposure to propofol. Methods Freshly isolated ventricular myocytes were obtained from normal and diabetic rat hearts. Intracellular concentration of Ca2+ and cell shortening were simultaneously measured in electrically stimulated, ventricular myocytes using fura-2 and video-edge detection, respectively. Postrest potentiation (PRP) and sarcoplasmic reticulum Ca2+ load were used to assess propofol-induced changes in the activity of the NCX. Results Propofol (10 microM) increased PRP in diabetic cardiomyocytes but had no effect on PRP in normal cardiomyocytes. Removal of sodium enhanced and KB-R7943 (reverse mode NCX inhibitor) blocked PRP in both normal and diabetic cardiomyocytes. In the absence of sodium, propofol enhanced PRP in diabetic cardiomyocytes but had no additional effect in normal cardiomyocytes. KB-R7943 completely blocked propofol-induced potentiation of peak intracellular concentration of Ca2+ and shortening in both cell types. Propofol increased sarcoplasmic reticulum Ca2+ load and prolonged removal of cytosolic Ca2+ in diabetic cardiomyocytes, but not in normal cardiomyocytes. Removal of sodium enhanced propofol-induced increases in sarcoplasmic reticulum Ca2+ load and further prolonged removal of cytosolic Ca2+, whereas KB-R7943 completely blocked propofol-induced increase in sarcoplasmic reticulum Ca2+ load. Protein kinase C inhibition with bisindolylmaleimide I prevented the propofol-induced increase in PRP and prolongation in Ca2+ removal. Conclusions These data suggest that propofol enhances PRP via activation of reverse mode NCX, but attenuates Ca2+ removal from the cytosol via inhibition of forward mode NCX in diabetic cardiomyocytes. The actions of propofol are mediated via a protein kinase C-dependent pathway.

Protein kinase C and preconditioning: role of the sarcoplasmic reticulum

2005 ◽  
Vol 289 (6) ◽  
pp. H2484-H2490 ◽  
Author(s):  
Ken Yamamura ◽  
Charles Steenbergen ◽  
Elizabeth Murphy
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Sarcoplasmic Reticulum ◽  
Ventricular Myocytes ◽  
Protein Phosphatase 1 ◽  
The Novel ◽  
Inhibitory Peptide ◽  
Adult Rat ◽  
Kinase C

Activation of protein kinase C (PKC) is cardioprotective, but the mechanism(s) by which PKC mediates protection is not fully understood. Inasmuch as PKC has been well documented to modulate sarcoplasmic reticulum (SR) Ca2+ and because altered SR Ca2+ handling during ischemia is involved in cardioprotection, we examined the role of PKC-mediated alterations of SR Ca2+ in cardioprotection. Using isolated adult rat ventricular myocytes, we found that addition of 1,2-dioctanoyl- sn-glycerol (DOG), to activate PKC under conditions that reduced myocyte death associated with simulated ischemia and reperfusion, also reduced SR Ca2+. Cell death was 57.9 ± 2.9% and 47.3 ± 1.8% in untreated and DOG-treated myocytes, respectively ( P < 0.05). Using fura 2 fluorescence to monitor Ca2+ transients and caffeine-releasable SR Ca2+, we examined the effect of DOG on SR Ca2+. Caffeine-releasable SR Ca2+ was significantly reduced (by ∼65%) after 10 min of DOG treatment compared with untreated myocytes ( P < 0.05). From our examination of the mechanism by which PKC alters SR Ca2+, we present the novel finding that DOG treatment reduced the phosphorylation of phospholamban (PLB) at Ser16. This effect is mediated by PKC-ε, because a PKC-ε-selective inhibitory peptide blocked the DOG-mediated decrease in phosphorylation of PLB and abolished the DOG-induced reduction in caffeine-releasable SR Ca2+. Using immunoprecipitation, we further demonstrated that DOG increased the association between protein phosphatase 1 and PLB. These data suggest that activated PKC-ε reduces SR Ca2+ content through PLB dephosphorylation and that reduced SR Ca2+ may be important in cardioprotection.

Protein kinase C-α and the regulation of diverse cell responses

2017 ◽  
Vol 8 (3-4) ◽  
pp. 143-153 ◽  
Author(s):  
Rishi Kant Singh ◽  
Sanjay Kumar ◽  
Pramod Kumar Gautam ◽  
Munendra Singh Tomar ◽  
Praveen Kumar Verma ◽  
...  
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Cellular Localization ◽  
Cellular Transformation ◽  
Cell Types ◽  
Adapter Proteins ◽  
Cellular Functions ◽  
Cell Responses ◽  
Kinase C ◽  
Cellular Compartments

AbstractProtein kinase C (PKC) comprises a family of lipid-sensitive enzymes that have been involved in a broad range of cellular functions. PKC-α is a member of classical PKC with ubiquitous expression and different cellular localization. This unique PKC isoform is activated by various signals which evoke lipid hydrolysis, after activation it interacts with various adapter proteins and is localized to specific cellular compartments where it is devised to work. The universal expression and activation by various stimuli make it a perfect player in uncountable cellular functions including differentiation, proliferation, apoptosis, cellular transformation, motility, adhesion and so on. However, these functions are not intrinsic properties of PKC-α, but depend on cell types and conditions. The activities of PKC-α are managed by the various pharmacological activators/inhibitors and antisense oligonucleotides. The aim of this review is to elaborate the structural feature, and provide an insight into the mechanism of PKC-α activation and regulation of its key biological functions in different cellular compartments to develop an effective pharmacological approach to regulate the PKC-α signal array.

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

2002 ◽  
Vol 282 (1) ◽  
pp. H320-H327 ◽  
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.

Mitogen stimulation of Na+-H+ exchange: differential involvement of protein kinase C

1987 ◽  
Vol 253 (2) ◽  
pp. C219-C229 ◽  
Author(s):  
L. L. Muldoon ◽  
G. A. Jamieson ◽  
A. C. Kao ◽  
H. C. Palfrey ◽  
M. L. Villereal
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Cell Types ◽  
Intact Cells ◽  
Kinase C ◽  
Protein Kinase C Activity ◽  
Human Fibroblast Strains ◽  
Stimulation Of

The mitogen-induced activation of Na+-H+ exchange was investigated in two cultured human fibroblast strains (HSWP and WI-38 cells) that, based on previous studies, differed in their response to the tumor-promoting phorbol ester 12-O-tetradecanoylphorbol-13-acetate (TPA) (L. M. Vincentini and M. L. Villereal, Proc. Natl. Acad. Sci. USA 82: 8053-8056, 1985). The role of protein kinase C in the activation of Na+-H+ exchange was investigated by comparing the effects of TPA on Na+ influx, in vitro phosphorylation, and in vivo phosphorylation in both cell types. Although both cell types have significant quantities of protein kinase C activity that can be activated by TPA in intact cells, the addition of TPA to intact cells stimulates Na+ influx in WI-38 cells but not in HSWP cells, indicating that in HSWP cells the stimulation of protein kinase C is not sufficient to activate the Na+-H+ exchanger. Cells were then depleted of protein kinase C activity by chronic treatment with high doses of TPA. Both HSWP and WI-38 cells were rendered protein kinase C deficient by this treatment as determined by in vitro and in vivo phosphorylation studies. Protein kinase C-deficient HSWP cells lose the ability for TPA to inhibit the serum-induced activation of Na+-H+ exchange, but there is no reduction in the stimulation of Na+ influx by serum, bradykinin, vasopressin, melittin, or vanadate, indicating that protein kinase C activity is not necessary for the mitogen-induced activation of Na+-H+ exchange in HSWP cells by agents known to stimulate phosphatidylinositol turnover (G. A. Jamieson and M. Villereal. Arch. Biochem. Biophys. 252: 478-486, 1987). In contrast, depletion of protein kinase C activity in WI-38 cells significantly reduces both the TPA- and the serum-induced activation of the Na+-H+ exchange system, suggesting that protein kinase C activity is necessary for at least a portion of the mitogen-induced activation of the Na+-H+ exchanger in WI-38 cells. These results indicate that the mechanisms for regulating Na+-H+ exchange can differ dramatically between different types of fibroblasts.

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

1992 ◽  
Vol 263 (5) ◽  
pp. C933-C940 ◽  
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.

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

1997 ◽  
Vol 272 (1) ◽  
pp. H350-H359 ◽  
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.

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

2012 ◽  
Vol 302 (8) ◽  
pp. C1141-C1151 ◽  
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.

scholarly journals Effect of secretagogues on chromogranin A synthesis in bovine cultured chromaffin cells. Possible regulation by protein kinase C

1989 ◽  
Vol 260 (3) ◽  
pp. 915-922 ◽  
Author(s):  
J P Simon ◽  
M F Bader ◽  
D Aunis
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Chromogranin A ◽  
Chromaffin Cells ◽  
Cell Types ◽  
Term Treatment ◽  
Synthesis Rate ◽  
Kinase C ◽  
Long Term Treatment ◽  
Bovine Chromaffin Cells

Chromogranin A is a major component of storage granules in many different secretory cell types. After [35S]methionine labelling of proteins from cultured bovine chromaffin cells, chromogranin A was immunoprecipitated with specific antibodies, and the radioactivity incorporated into chromogranin A was determined and used as an index of its synthesis rate. Depolarization of cells with nicotine or high K+ evoked a Ca2+-dependent increase in chromogranin A synthesis, whereas muscarine, which does not evoke significant Ca2+ influx from bovine chromaffin cells, had no effect on chromogranin A synthesis. Forskolin, an activator of adenylate cyclase, affected neither the basal nor the nicotine-stimulated rate of chromogranin A synthesis. In contrast, 12-O-tetradecanoylphorbol 13-acetate (TPA), an activator of protein kinase C, significantly enhanced the incorporation of radioactivity into chromogranin A. Sphingosine, an inhibitor of protein kinase C, abolished both nicotine-stimulated and TPA-induced chromogranin A synthesis. In addition, long-term treatment of chromaffin cells with TPA decreased protein kinase C activity and inhibited the nicotine-stimulated chromogranin A synthesis. These results suggest that protein kinase C may play an important role in the control of chromogranin A synthesis.

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