scholarly journals Impaired membrane translocation of thrombin stimulated PKC epsilon by high glucose

1998 ◽  
Vol 157 (2) ◽  
pp. R7-10
Author(s):  
G Reining ◽  
S Baumgartner-Parzer ◽  
W Waldhausl
Keyword(s):  
Umbilical Vein ◽  
Area Under The Curve ◽  
Resting Cells ◽  
Kinase C ◽  
Pkc Epsilon ◽  
Pkc Isoforms ◽  
Membrane Bound ◽  
Pkc Alpha ◽  
Umbilical Vein Endothelial Cells

Hyperglycaemia is known to cause endothelial dysfunction and to promote diabetic angiopathy. Therefore, this study was designed to evaluate the effect of long term incubation (16 +/- 1 days) in 30 mM vs 5 mM glucose on ligand induced translocation of protein kinase C (PKC) in paired cultures of individual isolates of human umbilical vein endothelial cells (HUVECs). Cells were stimulated with increasing concentrations of thrombin (0.01, 0.1, 1, 10 and 100 nM) for 30 seconds in the presence of 5 mM and 30 mM glucose, respectively, and analyzed by immunoblotting for PKC-isoforms alpha and epsilon. Stimulation by thrombin of confluent cultures displayed a concentration dependent rise in membrane bound PKC alpha and epsilon. Translocation of PKC alpha by thrombin remained unaffected by high versus normal ambient glucose, whereas translocation of PKC epsilon in cells grown in 30mM glucose was reduced at maximal thrombin concentrations (area under the curve, AUC: 90.4 +/- 7% of control cells; p < 0.008; n = 6) versus control cultures kept in 5mM glucose. In the identical isolates translocation of PKC epsilon was not reduced by 30 mM mannitol used as osmotic control. No change was induced by long term incubation of resting cells with 30 mM vs 5 mM glucose as to total and membrane bound PKC alpha or PKC epsilon. The obtained data suggest modulation by 30 mM glucose of ligand induced PKC translocation in an isoform specific manner, whereas subcellular distribution of PKC isoforms in the absence of thrombin stimulation remains unaffected by 30 mM glucose.

scholarly journals Characterization of the interactions between procoagulant albumin and human endothelial cells

Blood ◽  
1993 ◽  
Vol 82 (9) ◽  
pp. 2684-2692
Author(s):  
KJ Faucette ◽  
LA Fitzgerald ◽  
L Liu ◽  
CJ Parker ◽  
GM Rodgers
Keyword(s):  
Endothelial Cells ◽  
Umbilical Vein ◽  
Quantitative Polymerase Chain Reaction ◽  
Scavenger Receptor ◽  
Kinase C ◽  
Normal Human ◽  
Membrane Bound ◽  
Polymerase Chain ◽  
Umbilical Vein Endothelial Cells

Normal human plasma contains procoagulant albumin (PC-Al), an anionic form of albumin that induces tissue factor (TF) activity in human umbilical vein endothelial cells (HUVEC) and monocytes. In this study, we investigated both the interactions between HUVEC and PC-Al and the mechanism by which PC-Al induces TF activity. Binding of PC-Al to HUVEC was specific and reversible. Further studies indicated that membrane- bound PC-Al was not internalized by HUVEC. A potential receptor on HUVEC was suggested by studies in which the capacity of a variety of reagents to inhibit the activity of PC-Al was quantitated. Induction of TF activity by PC-Al was antagonized by dextran sulfate, heparin, fucoidan, and concanavalin A but not by ovalbumin, polyglutamic acid, or polyvinyl sulfate. This competition profile bears similarities to those reported for scavenger receptors that have been identified on both HUVEC and monocytes. Involvement of protein kinase C (PKC) in the PC-Al-induced enhancement of TF activity was suggested by experiments in which staurosporine, an inhibitor of PKC, suppressed the activity of PC-Al. The induction of TF activity by PC-Al was further characterized by using a quantitative polymerase chain reaction assay. Increased TF mRNA was first seen after 1 hour of incubation with PC-Al. Maximal observed expression occurred at 2 hours, but at 5 hours, expression had significantly decreased. Monocytes could also be induced to express TF mRNA after a 2-hour incubation with PC-Al. These results suggest that the functionally relevant binding of PC-Al to HUVEC may be mediated through interactions with a membrane constituent that has some of the properties of a scavenger receptor and that this interaction augments TF activity by enhancing transcription of TF mRNA, at least in part, by a mechanism that is dependent on activation of PKC.

Do adult rat ventricular myocytes express protein kinase C-alpha?

1997 ◽  
Vol 272 (5) ◽  
pp. H2485-H2491 ◽  
Author(s):  
V. Rybin ◽  
S. F. Steinberg
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Ventricular Myocytes ◽  
Chromatographic Purification ◽  
Adult Rat ◽  
Pkc Delta ◽  
Kinase C ◽  
Pkc Epsilon ◽  
Pkc Isoforms ◽  
Pkc Alpha

Although calcium-insensitive protein kinase C (PKC) isoforms (PKC-epsilon and PKC-delta) are consistently detected in adult ventricular myocytes, the evidence that adult ventricular myocytes also express calcium-sensitive PKC-alpha is inconsistent. The current study used four different anti-PKC-alpha-antibodies to resolve some of the uncertainties regarding the immunodetection of PKC-alpha in adult ventricular myocytes. Three of the antibodies used in this study barely (GIBCO-BRL) or rather faintly (Transduction Laboratories and Seikagaku America) recognize PKC-alpha in crude preparations from adult ventricular myocytes. Although each of these antibodies recognizes a prominent 80-kDa band, which is similar in size to PKC-alpha, this represents nonspecific immunoreactivity and should not be confused with PKC-alpha. This conclusion is based on peptide-blocking experiments (GIBCO-BRL), the absence of the requisite sensitivity to calcium- and phorbol 12-myristate 13-acetate-induced translocation (Seikagaku America and Transduction Laboratories), and/or the failure to copurify with PKC-alpha on DEAE-Sephacel chromatography. Nevertheless, an antibody from Upstate Biotechnology clearly recognizes PKC-alpha and not other unrelated nonspecific immunoreactive species in crude preparations from adult ventricular myocytes. Each of the antisera used in this study could detect PKC-alpha immunoreactivity following chromatographic purification of the samples to enrich for PKC-alpha and remove nonspecific immunoreactive proteins. These results suggest that PKC-alpha is expressed by adult ventricular myocytes and argue that differences in the sensitivity and/or specificity of available antisera contribute to at least some of the confusion regarding PKC-alpha expression in adult ventricular myocytes.

scholarly journals Characterization of the interactions between procoagulant albumin and human endothelial cells

Blood ◽  
1993 ◽  
Vol 82 (9) ◽  
pp. 2684-2692 ◽  
Author(s):  
KJ Faucette ◽  
LA Fitzgerald ◽  
L Liu ◽  
CJ Parker ◽  
GM Rodgers
Keyword(s):  
Endothelial Cells ◽  
Umbilical Vein ◽  
Quantitative Polymerase Chain Reaction ◽  
Scavenger Receptor ◽  
Kinase C ◽  
Normal Human ◽  
Membrane Bound ◽  
Polymerase Chain ◽  
Umbilical Vein Endothelial Cells

Abstract Normal human plasma contains procoagulant albumin (PC-Al), an anionic form of albumin that induces tissue factor (TF) activity in human umbilical vein endothelial cells (HUVEC) and monocytes. In this study, we investigated both the interactions between HUVEC and PC-Al and the mechanism by which PC-Al induces TF activity. Binding of PC-Al to HUVEC was specific and reversible. Further studies indicated that membrane- bound PC-Al was not internalized by HUVEC. A potential receptor on HUVEC was suggested by studies in which the capacity of a variety of reagents to inhibit the activity of PC-Al was quantitated. Induction of TF activity by PC-Al was antagonized by dextran sulfate, heparin, fucoidan, and concanavalin A but not by ovalbumin, polyglutamic acid, or polyvinyl sulfate. This competition profile bears similarities to those reported for scavenger receptors that have been identified on both HUVEC and monocytes. Involvement of protein kinase C (PKC) in the PC-Al-induced enhancement of TF activity was suggested by experiments in which staurosporine, an inhibitor of PKC, suppressed the activity of PC-Al. The induction of TF activity by PC-Al was further characterized by using a quantitative polymerase chain reaction assay. Increased TF mRNA was first seen after 1 hour of incubation with PC-Al. Maximal observed expression occurred at 2 hours, but at 5 hours, expression had significantly decreased. Monocytes could also be induced to express TF mRNA after a 2-hour incubation with PC-Al. These results suggest that the functionally relevant binding of PC-Al to HUVEC may be mediated through interactions with a membrane constituent that has some of the properties of a scavenger receptor and that this interaction augments TF activity by enhancing transcription of TF mRNA, at least in part, by a mechanism that is dependent on activation of PKC.

scholarly journals Effects of insulin on the translocation of protein kinase C-θ and other protein kinase C isoforms in rat skeletal muscles

1995 ◽  
Vol 308 (1) ◽  
pp. 177-180 ◽  
Author(s):  
K Yamada ◽  
A Avignon ◽  
M L Standaert ◽  
D R Cooper ◽  
B Spencer ◽  
...  
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Skeletal Muscles ◽  
Phorbol Esters ◽  
Kinase C ◽  
Pkc Epsilon ◽  
Pkc Isoforms ◽  
Pkc Alpha

Protein kinase C (PKC)-theta is a newly recognized major PKC isoform in skeletal muscle. In this study we found that insulin provoked rapid biphasic increases in membrane-associated immunoreactive PKC-theta, as well as PKC-alpha, PKC-beta and PKC-epsilon, in rat soleus muscles incubated in vitro. Effects of insulin on PKC isoforms in the soleus were comparable in magnitude with those of phorbol esters. Increases in membrane-associated PKC-theta, PKC-alpha, PKC-beta and PKC-epsilon were also observed in rat gastrocnemius muscles after insulin treatment in vivo. Our findings suggest that PKC-theta, like other diacylglycerol-sensitive PKC isoforms (alpha, beta and epsilon), may play a role in insulin action in skeletal muscles.

scholarly journals Protein kinase C-theta isoenzyme selective stimulation of the transcription factor complex AP-1 in T lymphocytes.

1996 ◽  
Vol 16 (4) ◽  
pp. 1842-1850 ◽  
Author(s):  
G Baier-Bitterlich ◽  
F Uberall ◽  
B Bauer ◽  
F Fresser ◽  
H Wachter ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Transcriptional Activation ◽  
Dominant Negative ◽  
Dominant Negative Mutant ◽  
Kinase C ◽  
Pkc Isoforms ◽  
Pkc Alpha ◽  
Transcriptional Complex ◽  
Induced Signal ◽  
Transcription Factor Complex

T-lymphocyte stimulation requires activation of several protein kinases, including the major phorbol ester receptor protein kinase C (PKC), ultimately leading to induction of lymphokines, such as interleukin-2 (IL-2). The revelant PKC isoforms which are involved in the activation cascades of nuclear transcription factors involved in IL-2 production have not yet been clearly defined. We have examined the potential role of two representative PKC isoforms in the induction of the IL-2 gene, i.e., PKC-alpha and PKC-theta, the latter being expressed predominantly in hematopoietic cell lines, particularly T cells. Similar to that of PKC-alpha, PKC-theta overexpression in murine EL4 thymoma cells caused a significant increase in phorbol 12-myristate 13-acetate (PMA)-induced transcriptional activation of full-length IL-2-chloramphenicol acetyltransferase (CAT) and NF-AT-CAT but not of NF-IL2A-CAT or NF-kappaB promoter-CAT reporter gene constructs. Importantly, the critical AP-1 enhancer element was differentially modulated by these two distinct PKC isoenzymes, since only PKC-theta but not PKC-alpha overexpression resulted in an approximately 2.8-fold increase in AP-1-collagenase promoter CAT expression in comparison with the vector control. Deletion of the AP-1 enhancer site in the collagenase promoter rendered it unresponsive to PKC-theta. Expression of a constitutively active mutant PKC-theta A148E (but not PKC-alpha A25E) was sufficient to induce activation of AP-1 transcription factor complex in the absence of PMA stimulation. Conversely, a catalytically inactive PKC-theta K409R (but not PKC-alpha K368R) mutant abrogated endogenous PMA-mediated activation of AP-1 transcriptional complex. Dominant negative mutant Ha-RasS17N completely inhibited the PKC-O A148E-induced signal, PKC-O. Expression of a constitutively active mutant PKC-O A148E (but not PKC-alpha A25E) was sufficient to induce activation of AP-1 transcription factor complex in the absence of PMA stimulation. Conversely, a catalytically inactive PKC-O K409R (but not PKC-alpha K368R) mutant abrogated endogenous PMA-mediated activation of AP-1 transcriptional complex. Dominant negative mutant Ha-enRasS17N completely inhibited in the PKC-O A148E-induced signal, identifying PKC-theta as a specific constituent upstream of or parallel to Ras in the signaling cascade leading to AP transcriptional activation.

scholarly journals Secretome of Senescent Adipose-Derived Mesenchymal Stem Cells Negatively Regulates Angiogenesis

2020 ◽  
Vol 21 (5) ◽  
pp. 1802 ◽  
Author(s):  
Andrey Ratushnyy ◽  
Mariia Ezdakova ◽  
Ludmila Buravkova
Keyword(s):  
Replicative Senescence ◽  
Umbilical Vein ◽  
Chorioallantoic Membrane ◽  
Dot Blot ◽  
In Ovo ◽  
Angiogenic Potential ◽  
Associated Proteins ◽  
Migration Capacity ◽  
Umbilical Vein Endothelial Cells

Nowadays, paracrine regulation is considered as a major tool of mesenchymal stem cell (MSC) involvement in tissue repair and renewal in adults. Aging results in alteration of tissue homeostasis including neovascularization. In this study, we examined the influence of replicative senescence on the angiogenic potential of adipose-derived MSCs (ASCs). Angiogenic activity of conditioned medium (CM) from senescent and “young” ASCs was evaluated in chorioallantoic membrane (CAM) assay in ovo using Japanese quail embryos. Also, the formation of capillary-like tubes by human umbilical vein endothelial cells (HUVECs) in 3D basement membrane matrix “Matrigel” and HUVEC migration capacity were analyzed. Multiplex, dot-blot and gene expression analysis were performed to characterize transcription and production of about 100 angiogenesis-associated proteins. The results point to decreased angiogenic potential of senescent ASC secretome in ovo. A number of angiogenesis-associated proteins demonstrated elevation in CM after long-term cultivation. Meanwhile, VEGF (key positive regulator of angiogenesis) did not change transcription level and concentration in CM. Increasing both pro- (FGF-2, uPA, IL-6, IL-8 etc.) and antiangiogenic (IL-4, IP-10, PF4, Activin A, DPPIV etc.) factors was observed. Some proangiogenic genes were downregulated (IGF1, MMP1, TGFB3, PDGFRB, PGF). Senescence-associated secretory phenotype (SASP) modifications after long-term cultivation lead to attenuation of angiogenic potential of ASC.

Protein kinase C-epsilon is the likely mediator of mucin exocytosis in human colonic cell lines

1997 ◽  
Vol 272 (1) ◽  
pp. G31-G37 ◽  
Author(s):  
D. H. Hong ◽  
J. F. Forstner ◽  
G. G. Forstner
Keyword(s):  
Protein Kinase C ◽  
Cell Line ◽  
Cell Lines ◽  
Mucin Secretion ◽  
T84 Cells ◽  
Kinase C ◽  
Pkc Epsilon ◽  
Pkc Alpha ◽  
Colonic Cells ◽  
Ht 29

The phorbol ester, phorbol 12-myristate 13-acetate (PMA), induces mucin secretion in the colonic tumor cell line T84 in a Ca(2+)-independent manner. To determine whether a specific protein kinase C (PKC) isoform is involved in colonic cells, we compared PMA-dependent mucin secretion by three human colonic tumor cell lines (T84, HT-29/A1, and LS 180) with the expression of PKC isoforms alpha, beta, delta, epsilon, and zeta, previously identified in human colon (L. A. Davidson, Y. H. Jiang, J. D. Derr, H. Aukema, J. R. Lupton, and R. S. Chapkin. Arch. Biochem. Biophys. 312:547-553, 1994). In each cell line PMA (10(-7) M) caused mucin secretion within 30 min. PMA-dependent mucin secretion was three to four times greater from HT-29/A1 and T84 cells than from LS 180 cells. All three-cell lines contained mRNA for PKC-alpha, PKC-epsilon, and PKC-zeta but not PKC-beta or -delta. Each cell line also expressed PKC-alpha, -epsilon, and -zeta protein. PKC-epsilon expression (mRNA and protein) was three to four times greater in HT-29/A1 and T84 cells than in LS 180 cells, correlating with PMA-responsive mucin secretion, whereas all cell lines contained similar levels of PKC-alpha mRNA and protein. When cells were stimulated by PMA, only PKC-epsilon was translocated from cytosol to membrane fractions early enough to stimulate mucin secretion. Because PKC-epsilon is also a Ca(2+)-independent isoform, it is likely to mediate mucin exocytosis in colonic cells.

PDGF and IL-1 induce and activate specific protein kinase C isoforms in mesangial cells

1996 ◽  
Vol 271 (1) ◽  
pp. F108-F113 ◽  
Author(s):  
M. B. Ganz ◽  
B. Saksa ◽  
R. Saxena ◽  
K. Hawkins ◽  
J. R. Sedor
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
De Novo ◽  
Mesangial Cells ◽  
De Novo Synthesis ◽  
Kinase C ◽  
Pkc Isoforms ◽  
Alpha Beta ◽  
Pkc Alpha

In vitro and in vivo data suggest a remarkable plasticity in the differentiated phenotype of intrinsic glomerular cells, which after injury express new structures and functions. We have shown that a protein kinase C (PKC) isoform, beta II, is expressed in diseased but not normal glomeruli. Since intrarenal cytokine synthesis has been implicated in the pathogenesis of progressive glomerular injury, we have hypothesized that these mediators induce a change in isoform profile. To test this hypothesis in vitro, we have determined whether platelet-derived growth factor (PDGF) and interleukin-1 (IL-1) alter the expression or activation of PKC isoforms in cultured mesangial cells (MCs). By immunoblot and ribonuclease (RNase) protection assays, both PDGF and IL-1 induce as early as 2 h de novo synthesis of PKC-beta II. Since MCs constitutively express PKC-alpha, -beta I, and -zeta, we also determined whether IL-1 or PDGF alter the activity of these isoforms. PDGF maximally induced translocation of PKC-alpha (10 min), -beta I (90 min), -epsilon (120 min), and -zeta (120 min) from the cytosolic to the membrane fraction. IL-1, in contrast, did not alter the distribution of alpha, beta I, or epsilon at any time measured but did induce PKC-zeta translocation. These data suggest inflammatory mediators regulate PKC isoform activity in diseased glomeruli both by de novo synthesis of unexpressed isoforms and by activation of constitutively expressed PKC isoforms.

Cyclical mechanical stretch enhances angiopoietin-2 and Tie2 receptor expression in cultured human umbilical vein endothelial cells

2003 ◽  
Vol 104 (4) ◽  
pp. 421-428 ◽  
Author(s):  
Hang CHANG ◽  
Bao-Wei WANG ◽  
Peiliang KUAN ◽  
Kou-Gi SHYU
Keyword(s):  
Endothelial Cells ◽  
Umbilical Vein ◽  
Mechanical Stretch ◽  
Receptor Proteins ◽  
Herbimycin A ◽  
Tie2 Receptor ◽  
Kinase C ◽  
Umbilical Vein Endothelial Cells ◽  
Angiopoietin 2 ◽  
Angiopoietin 1

Endothelial cells are essential for neovascularization. Angiopoietins and Tie receptors are required for a normal vasculature. How cyclical mechanical stretch affects the expression of components of the angiopoietin system is not known. In this study, we investigated the regulation of angiopoietins and Tie receptors by cyclical mechanical stretch in cultured human umbilical vein endothelial cells (HUVECs). HUVECs grown on a flexible membrane base were stretched by vacuum to 20% elongation, at 60cycles/min. The levels of angiopoietin-2 protein began to increase as early as 2h after stretch was initially applied, reached a maximum of 2.7-fold over the control value by 6h. The Tie2 receptor protein showed the same pattern as Ang-2. These increases in angiopoietin-2 and Tie2 receptor proteins at 6h were blocked by the addition (30min before stretch) of the protein kinase C inhibitor Gö6976 (16nM) or the tyrosine kinase inhibitor herbimycin A (24µM). Similar to protein expression, the levels of angiopoietin-2 and Tie2 receptor mRNAs in HUVECs increased 3.1-fold and 2.5-fold respectively after stretch for 6h. These increases were also blocked by Gö6976 or herbimycin A. Cyclical mechanical stretch increased (and Gö6976 or herbimycin A abrogated these increases) the immunohistochemical labelling of angiopoietin-2 and Tie2 receptor after a 6h stretch. The levels of angiopoietin-1 and Tie1 receptor proteins, mRNAs and immunohistochemical staining were unaffected by cyclical mechanical stretch. Thus cyclical mechanical stretch activates the expression of angiopoietin-2 and the Tie2 receptor, but not angiopoietin-1 or the Tie1 receptor, in cultured HUVECs. This mechanical effect is probably mediated by the tyrosine kinase and protein kinase C pathways.

scholarly journals Nerve growth factor activates calcium-insensitive protein kinase C-ɛ in PC-12 rat pheochromocytoma cells

1993 ◽  
Vol 295 (3) ◽  
pp. 767-772 ◽  
Author(s):  
M Ohmichi ◽  
G Zhu ◽  
A R Saltiel
Keyword(s):  
Protein Kinase C ◽  
Nerve Growth Factor ◽  
Growth Factor ◽  
Protein Kinase ◽  
Kinase Activity ◽  
Pheochromocytoma Cells ◽  
Pc 12 Cells ◽  
Kinase C ◽  
Pkc Epsilon ◽  
Pkc Alpha

Protein kinase C (PKC) family members were examined in PC-12 rat pheochromocytoma cells to evaluate their role in the action of nerve growth factor (NGF). Immunoblot analysis of whole cell lysates using antibodies against various PKC isoforms revealed that PC-12 cells contained PKC-alpha, -delta, -epsilon and zeta. Assay of the protein kinase activity in these different anti-PKC immunoprecipitates demonstrated that NGF stimulated the kinase activity of PKC-epsilon, but not PKC-alpha, -delta and -zeta. Both histone phosphorylation and autophosphorylation of PKC-epsilon were increased by treatment of PC-12 cells with NGF. This increased phosphorylation observed in vitro is rapid, occurring maximally at 2.5 min and declining thereafter. Moreover, this effect of NGF is dose-dependent over physiological concentrations of the growth factor. Although the mechanistic basis for this specificity in PKC activation is not clear, NGF acutely stimulated the production of diacylglycerol without causing corresponding changes in intracellular Ca2+ concentrations. These results suggest that NGF may selectively stimulate the Ca(2+)-insensitive epsilon isoform of PKC by a phosphatidylinositol-independent mechanism.

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