Role of protein kinase C in angiotensin II-induced renal vasoconstriction in genetically hypertensive rats

1996 ◽  
Vol 270 (6) ◽  
pp. F945-F952 ◽  
Author(s):  
X. Ruan ◽  
W. J. Arendshorst
Keyword(s):  
Blood Flow ◽  
Protein Kinase C ◽  
Angiotensin Ii ◽  
Ang Ii ◽  
Hypertensive Rats ◽  
Renal Vasoconstriction ◽  
Kinase C ◽  
Pkc Activation ◽  
Genetically Hypertensive

The renal vasculature of young spontaneously hypertensive rats (SHR) responds to angiotensin II (ANG II) with exaggerated vasoconstriction, due in part to defective buffering by the adenosine 3',5'-cyclic monophosphate (cAMP) pathway. In vitro studies suggest greater activation of phospholipase C and protein kinase C (PKC) in cultured mesangial cells and vascular smooth muscle cells. The present studies evaluated the role of PKC activation in renal vascular responses to ANG II receptor activation and the relative contributions in SHR vs. Wistar-Kyoto control rats (WKY). Renal blood flow was measured in 8-wk-old anesthetized SHR and WKY pretreated with indomethacin. ANG II (2 ng) injection into the renal artery produced a transient 45-50% maximum reduction of renal blood flow in both rat strains. Intrarenal infusion of either staurosporine or chelerythrine into the renal artery effectively attenuated the vasoconstriction elicited by ANG II in a dose-dependent manner, with maximum inhibition of 60-70%. The PKC inhibitory effects were significant and independent of strain. Coadministration of the PKC inhibitors produced maximal inhibition similar to that observed with one agent, suggesting action via a common pathway. In other studies, the linkage of the PKC pathway to the AT1 receptor was evaluated using sub and maximal doses of losartan to antagonize 50-80% of ANG II-induced vasoconstriction. The same degree of inhibition was observed when a PKC inhibitor was coadministered with losartan. These findings support the views that the PKC system is a major intracellular signaling pathway coupled to the AT1 receptor in renal resistance vessels and that PKC activation is involved to similar degrees in the renal vasoconstriction elicited by ANG II in young WKY and SHR. Exaggerated vascular reactivity to vasoconstrictor agents in genetically hypertensive animals is probably due to a defect in cAMP generation in the presence of a normally operating PKC pathway.

scholarly journals Rate of calcium entry determines the rapid changes in protein kinase C activity in angiotensin II-stimulated adrenal glomerulosa cells

1994 ◽  
Vol 297 (3) ◽  
pp. 523-528 ◽  
Author(s):  
I Kojima ◽  
N Kawamura ◽  
H Shibata
Keyword(s):  
Protein Kinase C ◽  
Angiotensin Ii ◽  
Protein Kinase ◽  
Specific Substrate ◽  
Ang Ii ◽  
Kinase C ◽  
Aldosterone Production ◽  
Glomerulosa Cells ◽  
Peptide Phosphorylation

The present study was conducted to monitor precisely the activity of protein kinase C (PKC) in adrenal glomerulosa cells stimulated by angiotensin II (ANG II). PKC activity in cells was monitored by measuring phosphorylation of a synthetic KRTLRR peptide, a specific substrate for PKC, immediately after the permeabilization of the cells with digitonin [Heasley and Johnson J. Biol. Chem. (1989) 264, 8646-8652]. Addition of 1 nM ANG II induced a gradual increase in KRTLRR peptide phosphorylation, which reached a peak at 30 min, and phosphorylation was sustained thereafter. When the action of ANG II was terminated by adding [Sar1,Ala8]ANG II, a competitive antagonist, both Ca2+ entry and KRTLRR phosphorylation ceased rapidly, whereas diacylglyercol (DAG) content was not changed significantly within 10 min. Similarly, when blockade of Ca2+ entry was achieved by decreasing extracellular Ca2+ to 1 microM or by adding 1 microM nitrendipine, KRTLRR peptide phosphorylation was decreased within 5 min. In addition, restoration of Ca2+ entry was accompanied by an immediate increase in KRTLRR peptide phosphorylation. Under the same condition, DAG content did not change significantly. We then examined the role of the PKC pathway in ANG II-induced aldosterone production. Ro 31-8220 inhibited ANG II-induced KRTLRR phosphorylation without affecting the activity of calmodulin-dependent protein kinase II. In the presence of Ro 31-8220, ANG II-mediated aldosterone production was decreased to approx. 50%. Likewise, intracellular administration of PKC19-36, a sequence corresponding to residues 19-36 of the regulatory domain of PKC known to inhibit PKC activity, attenuated ANG II-mediated activation of PKC and aldosterone output. These results indicate a critical role of Ca2+ entry in the regulation of PKC activity by ANG II.

Angiotensin-mediated phosphatidylcholine hydrolysis and protein kinase C activation in mesangial cells

1993 ◽  
Vol 265 (4) ◽  
pp. C1100-C1108 ◽  
Author(s):  
R. L. Barnett ◽  
L. Ruffini ◽  
L. Ramsammy ◽  
R. Pasmantier ◽  
M. M. Friedlaender ◽  
...  
Keyword(s):  
Protein Kinase C ◽  
Angiotensin Ii ◽  
Protein Kinase ◽  
Phospholipase D ◽  
Mesangial Cells ◽  
Ang Ii ◽  
Kinase C ◽  
Pi Hydrolysis ◽  
Pkc Activation ◽  
Protein Kinase C Activation

Angiotensin II (ANG II) in mesangial cells (MC) promotes phosphatidylinositol (PI) hydrolysis resulting in diacylglycerol (DAG)-mediated increases in protein kinase C (PKC) activity. The paucity of MC inositol lipid prompted us to consider whether phosphatidylcholine (PC) could sustain DAG formation. ANG II released choline and increased phosphatidylethanol (PEt) via PC-phospholipase D (PC-PLD). ANG II also stimulated phosphorylcholine consequent to PC-phospholipase C (PC-PLC) activation. ANG II-mediated PC hydrolysis augmented DAG for 30 min. PC breakdown was influenced by extracellular Ca2+, because Ni2+ partially inhibited ANG II-induced PEt and obliterated agonist-mediated DAG formation. The consequence of Ca2+ modulation of PC metabolism was investigated by measuring PKC activity. Ni2+ had no effect on early (PI-associated) activation by ANG II at 90 s but obviated translocation from cytosol to the membrane at 10 min. The pathway responsible for PC-associated DAG was studied in PKC downregulated cells. Whereas downregulation prevented PLD-mediated PEt elevation, ANG II-stimulated DAG formation in myristate-labeled cells was unaltered, indicating PC-PLC activation. In summary, ANG II stimulates PC-PLD and PC-PLC in MC. PC-PLD is tightly regulated by PKC, whereas PC-PLC is stringently controlled by extracellular Ca2+. ANG II mediated PC breakdown principally via PC-PLC provides a mechanism for maintaining elevated DAG levels and PKC activation.

scholarly journals Role of protein kinase C in renal vasoconstriction caused by angiotensin II

1990 ◽  
Vol 259 (3) ◽  
pp. C421-C426 ◽  
Author(s):  
H. Scholz ◽  
A. Kurtz
Keyword(s):  
Protein Kinase C ◽  
Angiotensin Ii ◽  
Protein Kinase ◽  
Rat Kidney ◽  
Channel Blockers ◽  
Ang Ii ◽  
Renal Vasoconstriction ◽  
Protein Kinase C Inhibitors ◽  
Kinase C ◽  
Renal Vascular

In this study we have examined the subcellar pathways along which angiotensin II (ANG II) causes renal vasoconstriction. Using the isolated perfused rat kidney model, we found that renal vasoconstriction produced by ANG II (100 pM) was not altered by the calmodulin antagonists calmidazolium (1 microM) and N-(6-aminohexyl)-5-chloro-1-naphthalensulfonamide (W-7, 10 microM) but was blunted by staurosporine (100 nM) and 1-(5-isoquinolinylsulfonyl)-2-methyl-piperazine (H-7, 50 microM), two structurally distinct putative protein kinase C inhibitors. The phorbol ester 4 alpha-phorbol 12,13-didecanoate (1-100 nM) did not alter renal vascular resistance, whereas phorbol 12-myristate 13-acetate (PMA, 1-100 nM) caused potent and dose-dependent vasoconstriction that was prevented by staurosporine (100 nM) and H-7 (50 microM). The vasoconstrictory effects of ANG II and PMA were attenuated by the calcium channel blockers verapamil (5 microM) and nifedipine (5 microM) and were reversibly inhibited when cobaltous chloride (2 mM) was added to the perfusate. Taken together, our findings support the concept that the renal vasoconstrictory effect of ANG II is essentially mediated by protein kinase C activation, which either requires or enhances the entrance of extracellular calcium.

scholarly journals Na+/K+ATPase activity inhibition and isoform-specific translocation of protein kinase C following angiotensin II administration in isolated eel enterocytes

2001 ◽  
Vol 168 (2) ◽  
pp. 339-346 ◽  
Author(s):  
S Marsigliante ◽  
A Muscella ◽  
S Greco ◽  
MG Elia ◽  
S Vilella ◽  
...  
Keyword(s):  
Protein Kinase C ◽  
Angiotensin Ii ◽  
Protein Kinase ◽  
Atpase Activity ◽  
Sodium Balance ◽  
Ang Ii ◽  
Isolated Enterocytes ◽  
Kinase C ◽  
Pkc Alpha ◽  
Pkc Activation

In the eel, angiotensin II (Ang II) has a role at the level of both gill chloride and kidney tubular cells, regulating sodium balance and therefore osmoregulation. The present study extends these findings to another important osmoregulatory organ - the intestine. Enterocytes were obtained from sea-water (SW)-acclimated eels to investigate the role of Ang II on the intestinal Na+/K+ATPase activity, because in SW-acclimated animals the intestine represents an important site of water and NaCl transport from the mucosal to the serosal side. This paper demonstrates that isolated enterocytes stimulated with increasing Ang II concentrations (0.01-100 nM) showed a dose-dependent inhibition of the Na+/K+ATPase activity. The threshold decrease was at 0.01 nM Ang II; it reached a maximum at 10 nM (81.5% inhibition) and did not decrease further with the use of higher hormone doses. These hormonal effects were blocked by a specific competitive antagonist of the AT1 receptor subtype, DuP-753 (100% inhibition at 10 microM), indicating that these effects are mediated by an AT1-like receptor. Isolated enterocytes stimulated with 10 nM Ang II showed a transient increase in intracellular calcium ([Ca2+]i), followed by a lower sustained phase. Removal of extracellular Ca2+ did not reduce the initial transient response and completely abolished the plateau phase. The inhibition of the Na+/K+ATPase activity was dependent on protein kinase C (PKC) activation since PKC antagonists (calphostin C and staurosporine) abolished the inhibitory effect of Ang II, and the PKC activator phorbol 12-myristate 13-acetate reduced transporter activity. Western blot analysis with antibodies to PKC alpha, beta I, beta II, gamma, delta, epsilon, iota, eta and zeta isoforms showed that eel enterocytes expressed the conventional isoforms (alpha and beta I), the novel isoforms (delta and eta) and the atypical isoforms (zeta and iota). Ang II stimulated the translocation from the cytosol to the plasma membrane of PKC alpha, PKC delta and PKC eta isoforms. In conclusion, our results suggest that Ang II modulates intestinal Na+/K+ATPase in SW-acclimated eels via calcium mobilization and PKC activation.

scholarly journals Role of tyrosine kinase and protein kinase C in the steroidogenic actions of angiotensin II, α-melanocyte-stimulating hormone and corticotropin in the rat adrenal cortex

1995 ◽  
Vol 305 (2) ◽  
pp. 433-438 ◽  
Author(s):  
S Kapas ◽  
A Purbrick ◽  
J P Hinson
Keyword(s):  
Protein Kinase C ◽  
Angiotensin Ii ◽  
Protein Kinase ◽  
Tyrosine Kinase ◽  
Zona Glomerulosa ◽  
Aldosterone Secretion ◽  
Melanocyte Stimulating Hormone ◽  
Kinase C ◽  
Stimulating Hormone

The role of protein kinases in the steroidogenic actions of alpha-melanocyte-stimulating hormone (alpha-MSH), angiotensin II (AngII) and corticotropin (ACTH) in the rat adrenal zona glomerulosa was examined. Ro31-8220, a potent selective inhibitor of protein kinase C (PKC), inhibited both AngII- and alpha-MSH-stimulated aldosterone secretion but had no effect on aldosterone secretion in response to ACTH. The effect of Ro31-8220 on PKC activity was measured in subcellular fractions. Basal PKC activity was higher in cytosol than in membrane or nuclear fractions. Incubation of the zona glomerulosa with either alpha-MSH or AngII resulted in significant increases in PKC activity in the nuclear and cytosolic fractions and decreases in the membrane fraction. These effects were all inhibited by Ro31-8220. ACTH caused a significant increase in nuclear PKC activity only, and this was inhibited by Ro31-8220 without any significant effect on the steroidogenic response to ACTH, suggesting that PKC translocation in response to ACTH may be involved in another aspect of adrenal cellular function. Tyrosine phosphorylation has not previously been considered to be an important component of the response of adrenocortical cells to peptide hormones. Both AngII and alpha-MSH were found to activate tyrosine kinase, but ACTH had no effect, observations that have not been previously reported. Tyrphostin 23, a specific antagonist of tyrosine kinases, inhibited aldosterone secretion in response to AngII and alpha-MSH, but not ACTH. These data confirm the importance of PKC in the adrenocortical response to AngII and alpha-MSH, and, furthermore, indicate that tyrosine kinase may play a critical role in the steroidogenic actions of AngII and alpha-MSH in the rat adrenal zona glomerulosa.

PDGF-induced mitogenic signaling is not mediated through protein kinase C and c-fos pathway in VSM cells

1993 ◽  
Vol 264 (1) ◽  
pp. C71-C79 ◽  
Author(s):  
R. V. Sharma ◽  
R. C. Bhalla
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Dna Synthesis ◽  
Thymidine Incorporation ◽  
Cytosolic Calcium ◽  
Platelet Derived Growth Factor ◽  
Kinase C ◽  
Pdgf Stimulation ◽  
Pkc Activation

This study examines the role of protein kinase C (PKC) in platelet-derived growth factor (PDGF)-induced vascular smooth muscle (VSM) cell proliferation and initial signaling events. A 24-h pretreatment of VSM cells with 200 nM phorbol 12-myristate 13-acetate (PMA) completely abolished immunologically reactive PKC activity. Depletion of PKC activity from VSM cells did not attenuate PDGF-stimulated [3H]thymidine incorporation compared with control cells. Similarly, acute activation of PKC by treatment with 200 nM PMA for 10 min had no effect on PDGF-mediated [3H]thymidine incorporation. Both PMA and PDGF increased c-fos induction to the same magnitude; however, treatment with PMA did not induce DNA synthesis in these cells. In PKC-depleted cells PDGF-mediated c-fos induction was reduced by 50-60%, while DNA synthesis in response to PDGF stimulation was not reduced. PKC depletion did not alter PDGF-stimulated increase in cytosolic calcium levels, 125I-PDGF binding, or receptor autophosphorylation. On the basis of these results, we conclude that PKC activation and c-fos induction do not play a significant role in PDGF-mediated mitogenesis in VSM cells.

scholarly journals Role of protein kinase C in Ca channel blocker-induced renal arteriolar dilation in spontaneously hypertensive rats

2005 ◽  
Vol 54 (2) ◽  
pp. 102-108 ◽  
Author(s):  
Koichi Hayashi ◽  
Shu Wakino ◽  
Yuri Ozawa ◽  
Koichiro Homma ◽  
Takeshi Kanda ◽  
...  
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Spontaneously Hypertensive Rats ◽  
Channel Blocker ◽  
Ca Channel ◽  
Hypertensive Rats ◽  
Spontaneously Hypertensive ◽  
Kinase C

scholarly journals Protein Kinase C-ε Induces Caveolin-Dependent Internalization of Vascular Adenosine 5′-Triphosphate–Sensitive K + Channels

Hypertension ◽  
2008 ◽  
Vol 52 (3) ◽  
pp. 499-506 ◽  
Author(s):  
Jundong Jiao ◽  
Vivek Garg ◽  
Baofeng Yang ◽  
Terry S. Elton ◽  
Keli Hu
Keyword(s):  
Smooth Muscle ◽  
Protein Kinase C ◽  
Angiotensin Ii ◽  
Protein Kinase ◽  
Cell Surface ◽  
Small Interfering Rna ◽  
Caveolin 1 ◽  
Kinase C ◽  
Interfering Rna ◽  
Pkc Activation

Vascular ATP-sensitive K + (K ATP ) channels are critical regulators of arterial tone and, thus, blood flow in response to local metabolic needs. They are important targets for clinically used drugs to treat hypertensive emergency and angina. It is known that protein kinase C (PKC) activation inhibits K ATP channels in vascular smooth muscles. However, the mechanism by which PKC inhibits the channel remains unknown. Here we report that caveolin-dependent internalization is involved in PKC-ε–mediated inhibition of vascular K ATP channels (Kir6.1 and SUR2B) by phorbol 12-myristate 13-acetate or angiotensin II in human embryonic kidney 293 cells and immortalized human saphenous vein vascular smooth muscle cells. We showed that Kir6.1 substantially overlapped with caveolin-1 at the cell surface. Cholesterol depletion with methyl-β-cyclodextrin significantly reduced, whereas overexpression of caveolin-1 largely enhanced, PKC-induced inhibition of Kir6.1/SUR2B currents. Importantly, we demonstrated that activation of PKC-ε caused internalization of K ATP channels, the effect that was blocked by depletion of cholesterol with methyl-β-cyclodextrin, expression of dominant-negative dynamin mutant K44E, or knockdown of caveolin-1 with small interfering RNA. Moreover, patch-clamp studies revealed that PKC-ε–mediated inhibition of the K ATP current induced by PMA or angiotensin II was reduced by a dynamin mutant, as well as small interfering RNA targeting caveolin-1. The reduction in the number of plasma membrane K ATP channels by PKC activation was further confirmed by cell surface biotinylation. These studies identify a novel mechanism by which the levels of vascular K ATP channels could be rapidly downregulated by internalization. This finding provides a novel mechanistic insight into how K ATP channels are regulated in vascular smooth muscle cells.

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