scholarly journals Anti-Malignant Ascites Effect of Total Diterpenoids from Euphorbiae ebracteolatae Radix Is Attributable to Alterations of Aquaporins via Inhibiting PKC Activity in the Kidney

Molecules ◽  
2021 ◽  
Vol 26 (4) ◽  
pp. 942
Author(s):  
Yuanbin Zhang ◽  
Dongfang Liu ◽  
Fan Xue ◽  
Hongli Yu ◽  
Hao Wu ◽  
...  
Keyword(s):  
Protein Kinase C ◽  
Antitumor Activity ◽  
Membrane Fraction ◽  
Collecting Duct ◽  
Human Kidney ◽  
Underlying Mechanism ◽  
Malignant Ascites ◽  
Kinase C ◽  
Collecting Duct Cells ◽  
Medullary Collecting Duct

This study evaluated the anti-ascites effect of total diterpenoids extracted from Euphorbiae ebracteolatae Radix (TDEE) on malignant ascitic mice and elucidated its underlying mechanism. TDEE was extracted by dichloromethane and subjected to column chromatography. The purity of six diterpenoids isolated from TDEE was determined to be 77.18% by HPLC. TDEE (3 and 0.6 g raw herbs/kg, p.o.) reduced ascites and increased urine output. Meanwhile, analysis of tumor cell viability, cycle and apoptosis indicated that TDEE had no antitumor activity. In addition, the expression levels of aquaporins (AQPs) and the membrane translocation levels of protein kinase C (PKC) α and PKCβ in kidney and cells were measured. TDEE reduced the levels of AQP1–4, and inhibited PKCβ expression in membrane fraction. Four main diterpenoids, except compound 2, reduced AQP1 level in human kidney-2 cells. Compounds 4 and 5 inhibited AQP2–4 expression in murine inner medullary collecting duct cells. The diterpenoid-induced inhibition of AQP1–4 expression was blocked by phorbol-12-myristate-13-acetate (PMA; agonist of PKC). The diterpenoids from TDEE are the main anti-ascites components. The anti-ascites effect of diterpenoids may be associated with alterations in AQPs in the kidneys to promote diuresis. The inhibition of AQP1–4 expression by TDEE is related to the inhibition of PKCβ activation.

Na(+)-H+ exchange is stimulated by protein kinase C activation in inner medullary collecting duct cells

1990 ◽  
Vol 259 (4) ◽  
pp. F666-F671 ◽  
Author(s):  
I. N. Slotki ◽  
J. H. Schwartz ◽  
E. A. Alexander
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Cell Activation ◽  
Phorbol Esters ◽  
Collecting Duct ◽  
Synthetic Analogue ◽  
Inner Medullary Collecting Duct ◽  
Kinase C ◽  
Medullary Collecting Duct ◽  
Free Media

In this study we investigated the role of protein kinases in activation of the Na(+)-H+ exchanger in inner medullary collecting duct (IMCD) cells. Monolayers, 24-48 h after achieving confluence, were made quiescent by 24 h incubation in 0.1% serum before study. Changes in pHi were measured with 2',7'-bis(carboxyethyl)-5(6)-carboxyfluorescein. Phorbol myristate acetate (PMA), a synthetic analogue of diacylglycerol (DAG), was used to stimulate protein kinase C (PKC). In nominally HCO3(-)-free media containing 110 mM Na+ and 1 mM Ca2+, PMA addition increased pHi from 7.29 +/- 0.08 to 7.54 +/- 0.07 after 20 min. The increment in pHi was completely inhibited by 1 mM amiloride or by replacement of extracellular Na+ with choline but not inhibited by 1 mM N-ethylmaleimide, an inhibitor of active proton transport. Downregulation of PKC by overnight incubation of monolayers with PMA also prevented the rise in pHi upon subsequent challenge with PMA. Another active analogue of DAG, 1,2-dioleoyl-rac-glycerol, caused an increment in pHi similar to that produced by PMA, whereas 4 alpha-phorbol, an inactive analogue, did not stimulate Na(+)-H+ exchange. Bradykinin (10(-6) M), a phospholipase C-activating hormone, also induces alkalinization of IMCD cells similar to that produced by phorbol esters. Neither vasopressin (10(-7) M), which induces cellular accumulation of adenosine 3-,5--cyclic monophosphate (cAMP) and activation of protein kinase A (PKA), nor 8-bromo-cAMP (1 mM) changed pHi. Therefore in the IMCD cell activation of PKC but not PKA stimulates a rise in pHi via the Na(+)-H+ exchanger.

Evidence for a role of protein kinase C-α in urine concentration

2004 ◽  
Vol 287 (2) ◽  
pp. F299-F304 ◽  
Author(s):  
Lijun Yao ◽  
Dan-Yang Huang ◽  
Imke L. Pfaff ◽  
Xin Nie ◽  
Michael Leitges ◽  
...  
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Collecting Duct ◽  
Sodium Reabsorption ◽  
Free Access ◽  
Wild Type ◽  
Urinary Osmolality ◽  
Kinase C ◽  
Medullary Collecting Duct ◽  
Lower Urinary

In mouse kidney, the conventional protein kinase C (PKC) isoenzyme α is expressed in glomeruli, the cortical collecting duct (intercalated cells only), and medullary collecting duct. To get insights on its function, PKC-α knockout (−/−) and wild-type (+/+) mice were studied. When provided free access to water, PKC-α −/− mice showed ∼50% greater urine flow rate and lower urinary osmolality in 24-h metabolic cage experiments despite a greater urinary vasopressin-to-creatinine ratio vs. PKC-α +/+ mice. Renal albumin excretion was not different. Clearance experiments under inactin/ketamine anesthesia revealed a modestly reduced glomerular filtration rate and showed a reduced absolute and fractional renal fluid reabsorption in PKC-α −/− mice. The sodium-restricting response to a low-sodium diet was unaffected in PKC-α −/− mice. Urinary osmolality was reduced to similar hypotonic levels in PKC-α −/− and +/+ mice during acute oral water loading or application of the vasopressin V2-receptor antagonist SR-121463. In comparison, the lower urinary osmolality observed in PKC-α −/− mice vs. wild-type mice under basal conditions persisted during water restriction for 36 h. In conclusion, PKC-α appears not to play a major role in renal sodium reabsorption but, consistent with its expression in the medullary collecting duct, contributes to urinary concentration in mice. Considering that PKC-βI and -βII are coexpressed with PKC-α in mouse medullary collecting duct, the present results indicate that conventional PKC isoenzymes cannot fully compensate for each other.

scholarly journals Cholinergic inhibition of Na-K-ATPase via activation of protein kinase C in Madin-Darby canine kidney cells.

1993 ◽  
Vol 4 (2) ◽  
pp. 195-205 ◽  
Author(s):  
L C Garg ◽  
P K Saha ◽  
D Mohuczy-Dominiak
Keyword(s):  
Atpase Activity ◽  
Mdck Cells ◽  
Collecting Duct ◽  
Madin Darby Canine Kidney ◽  
Cholinergic Agonists ◽  
Kinase C ◽  
Collecting Duct Cells ◽  
Medullary Collecting Duct ◽  
Darby Canine Kidney ◽  
Canine Kidney

Recently, it was reported that muscarinic-type cholinergic receptors coupled to the phosphoinositide messenger system are present in the rabbit inner medullary collecting duct and Madin-Darby canine kidney (MDCK) cells. The receptor density in MDCK cells is 50 times more than that in inner medullary collecting duct cells. To examine if muscarinic receptor activation influences Na-K-ATPase, the effects of a cholinergic agonist, carbachol, on Na-K-ATPase activity in MDCK cells were measured. Carbachol inhibited Na-K-ATPase activity in a time- and concentration-dependent manner. A maximum of approximately 80% of the enzyme activity was inhibited in 160 min with an EC50 of 5 microM carbachol. The inhibition of Na-K-ATPase activity was reversible; up to 80% of the enzyme activity was recovered within 4 h after carbachol was removed. The inhibitory effect of carbachol was blocked by a muscarinic antagonist atropine and by inhibitors of protein kinase C (PKC), 1-(5-isoquinolinesulfonyl)-2-methyl-piperazine HCl, and N-(2-(methylamino)ethyl)-5-isoquinoline sulfonamide HCl. Direct activators of PKC, phorbol 12-myristate 13-acetate, N(n-heptyl)-5-chloro-1-naphthalene sulfonamide, and phosphatidyl serine, also inhibited Na-K-ATPase activity in MDCK cells, and their effect was also blocked by PKC inhibitors. These results indicate that cholinergic agonists inhibit Na-K-ATPase activity in MDCK cells by the activation of PKC. It is concluded that the inhibition of Na-K-ATPase by PKC may, in part, be responsible for the natriuretic action of cholinergic agonists, which have been shown to stimulate phosphoinositide hydrolysis in renal collecting duct cells.

Immunolocalization of protein kinase C isoenzymes α, βI, βII, δ, and ε in mouse kidney

2004 ◽  
Vol 287 (2) ◽  
pp. F289-F298 ◽  
Author(s):  
Stephanie Redling ◽  
Imke L. Pfaff ◽  
Michael Leitges ◽  
Volker Vallon
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Knockout Mice ◽  
Collecting Duct ◽  
Mouse Kidney ◽  
Laser Scanning Microscopy ◽  
Intercalated Cells ◽  
Cell Extracts ◽  
Kinase C ◽  
Medullary Collecting Duct

Localization of protein kinase C (PKC) isoenzymes α, βI, βII, δ, and ε was studied employing Western blot analysis and immunohistochemical methods including confocal laser-scanning microscopy in the kidney of two mice strains, namely, C57BL/6 and 129/Sv, which have recently been used as genetic backgrounds for respective knockout mice. Immunoblot analysis identified immunoreactive bands for each isoenzyme in total kidney cell extracts. Isoenzyme expression sites were identical for both strains. Glomeruli expressed PKC-α, -βI, and -ε. The latter isoenzme was also detected in apical aspects of proximal convoluted but not in proximal straight tubules. In contrast to rats, neither PKC-α nor PKC-βI was detectable in the proximal tubule. Immunofluorescence was observed in luminal membranes of medullary (MTAL) and cortical thick ascending limbs for PKC-βI and in MTAL for PKC-ε. The cortical collecting duct expressed PKC-α, -βI, and -δ in intercalated cells only. In the outer medullary collecting duct, PKC-α and -βI were detectable in principal cells, whereas PKC-δ was found in intercalated cells. In the inner medullary collecting duct, PKC-α, -βI, and -βII were detected. As described for the rat, the expression of PKC-βII was otherwise restricted to cortical and medullary interstitial cells. The specificity of all labeling was confirmed in respective PKC isoenzyme knockout mice. In summary, distinct expression patterns were shown for PKC isoenzymes α, βI, βII, δ, and ε in the mouse kidney.

Effect of phorbol myristate acetate on secretion of parathyroid hormone

1988 ◽  
Vol 254 (1) ◽  
pp. E63-E70 ◽  
Author(s):  
J. J. Morrissey
Keyword(s):  
Protein Kinase C ◽  
Parathyroid Hormone ◽  
Protein Kinase ◽  
Membrane Fraction ◽  
Hormone Secretion ◽  
Myristate Acetate ◽  
Kinase C ◽  
Low Calcium ◽  
Protein Kinase C Activity ◽  
High Calcium

The influence of phorbol myristate acetate (PMA), an activator of protein kinase c, on the secretion of parathyroid hormone from collagenase-dispersed bovine parathyroid cells was tested. The cells were incubated at low (0.5 mM) or high (2.0 mM) concentrations of calcium in the medium, and the hormone secreted into the medium was measured by a radioimmunoassay that recognizes both intact and C-terminal fragments of hormone. At low calcium, the secretory rate averaged 32 +/- 3.8 ng.h-1.(10(5) cells)-1. The addition of 1.6 microM PMA did not affect secretion. At high calcium there was a significant suppression of secretion by 38% to 19.8 +/- 3 ng.h-1.(10(5) cells)-1. The addition of 1.6 microM PMA significantly stimulated hormone secretion to 35.8 +/- 8 ng.h-1.(10(5) cells)-1, a rate indistinguishable from low calcium. This stimulatory effect of PMA at high calcium was seen at PMA concentrations as low as 1.6 nM, did not occur with a biologically inactive 4 alpha-isomer of phorbol ester, and was independent of changes in cellular adenosine 3',5'-cyclic monophosphate levels. Examination of 32P-labeled phosphoproteins by two-dimensional gel electrophoresis revealed acidic proteins of approximately 20,000 and 100,000 Da that were phosphorylated at low and high calcium + 1.6 microM PMA but not at high calcium alone. The protein kinase c activity associated with the membrane fraction of parathyroid cells significantly decreased 40% when the cells were incubated at high vs. low calcium. The data suggest that calcium may regulate parathyroid hormone secretion through changes in protein kinase c activity of the membrane fraction of the cell and protein phosphorylation.

scholarly journals Arginine Vasopressin Potentiates the Stimulatory Action of CRH on Pituitary Corticotropes via a Protein Kinase C–Dependent Reduction of the Background TREK-1 Current

Endocrinology ◽  
2015 ◽  
Vol 156 (10) ◽  
pp. 3661-3672 ◽  
Author(s):  
Andy K. Lee ◽  
Frederick W. Tse ◽  
Amy Tse
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Arginine Vasopressin ◽  
Underlying Mechanism ◽  
Sk Channels ◽  
Acth Secretion ◽  
Patch Clamp Technique ◽  
Stimulatory Action ◽  
Kinase C ◽  
Perforated Patch Clamp

The hypothalamic hormone arginine vasopressin (AVP) potentiates the stimulatory action of CRH on ACTH secretion from pituitary corticotropes, but the underlying mechanism is elusive. Using the perforated patch-clamp technique to monitor membrane potentials in mouse corticotropes, we found that AVP triggered a transient hyperpolarization that was followed by a sustained depolarization. The hyperpolarization was caused by intracellular Ca2+ release that in turn activated the small conductance Ca2+-activated K+ (SK) channels. The depolarization was due to the suppression of background TWIK-related K+ (TREK)-1 channels. Direct activation of protein kinase C (PKC) reduced the TREK-1 current, whereas PKC inhibition attenuated the AVP-mediated reduction of the TREK-1 current, implicating the involvement of PKC. The addition of CRH (which stimulates the protein kinase A pathway) in the presence of AVP, or vice versa, resulted in further suppression of the TREK-1 current. In corticotropes with buffered cytosolic Ca2+ concentration ([Ca2+]i), AVP evoked a sustained depolarization, and the coapplication of AVP and CRH caused a larger depolarization than that evoked by AVP or CRH alone. In cells with minimal perturbation of [Ca2+]i and background TREK-1 channels, CRH evoked a sustained depolarization that was superimposed with action potentials, and the subsequent coapplication of AVP and CRH triggered a transient hyperpolarization that was followed by a larger depolarization. In summary, AVP and CRH have additive effects on the suppression of the TREK-1 current, resulting in a more robust depolarization in corticotropes. We suggest that this mechanism contributes to the potentiating action of AVP on CRH-evoked ACTH secretion.

Sign in / Sign up

Export Citation Format

Share Document