Vasopressin and phorbol ester-stimulated phosphatidylcholine metabolism in mesangial cells

1992 ◽  
Vol 262 (2) ◽  
pp. F185-F191 ◽  
Author(s):  
D. A. Troyer ◽  
O. F. Gonzalez ◽  
R. M. Padilla ◽  
J. I. Kreisberg
Keyword(s):  
Phosphatidic Acid ◽  
Phospholipase D ◽  
Myristic Acid ◽  
Culture Medium ◽  
Mesangial Cells ◽  
Additive Effects ◽  
Glomerular Mesangial Cells ◽  
Vasoactive Agents ◽  
Kinase C ◽  
Phosphatidylcholine Metabolism

We have studied the effects of the vasoactive agents phorbol 12-myristate 13-acetate (PMA) and vasopressin (VP) on phosphatidylcholine metabolism in cultured rat glomerular mesangial cells. PMA and VP stimulate the incorporation of [3H]choline into phosphatidylcholine and the release of [3H]choline into the culture medium. VP, but not PMA, also increases the release of phosphorylcholine into the medium. This suggests that PMA specifically stimulates phospholipase D, whereas VP stimulates phospholipases C and D. Experiments were also conducted to look for production of phosphatidic acid and diacylglycerol, products of phospholipase D- and C-mediated breakdown of phosphatidylcholine. Treatment of cells prelabeled with [3H]myristic acid for 2.5 min with PMA or VP increases the content of [3H]myristic acid in diacylglycerol and phosphatidic acid. A dual labeling study ([3H]myristic acid and [14C]arachidonic acid) suggests that phosphatidylcholine is an important source of diacylglycerol in cells treated with VP and PMA. When PMA or VP are added to [3H]myristic acid-labeled cells in the presence of ethanol, increased labeling of phosphatidylethanol is seen as early as 2.5 min. Desensitization of protein kinase C by overnight treatment of cells with PMA blocked subsequent VP-stimulated formation of phosphatidylethanol and release of [3H]choline. When cells were simultaneously treated with VP and PMA, additive effects on phosphatidylethanol formation and [3H]choline release were observed.

Endothelin stimulates phosphatidic acid formation in cultured rat mesangial cells: Role of a protein kinase C-regulated phospholipase D

1992 ◽  
Vol 150 (3) ◽  
pp. 578-585 ◽  
Author(s):  
Mark Kester ◽  
Michael S. Simonson ◽  
R. Guy McDermott ◽  
Elisabetta Baldi ◽  
Michael J. Dunn
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Phosphatidic Acid ◽  
Phospholipase D ◽  
Mesangial Cells ◽  
Acid Formation ◽  
Kinase C

Phorbol Esters Stimulate Phospholipase D Activity in C-6 Glioma Cells

1989 ◽  
Vol 16 (3) ◽  
pp. 257-262
Author(s):  
Lena Gustavsson ◽  
Christofer Lundqvist ◽  
Christer Ailing
Keyword(s):  
Arachidonic Acid ◽  
Phosphatidic Acid ◽  
Phospholipase D ◽  
Culture Medium ◽  
Phorbol Esters ◽  
Glioma Cells

The effects of phorbol esters on phospholipase D activity were studied in C-6 glioma cells. The cell lipids were prelabelled with [3H]-glycerol or [14C]-arachidonic acid. Phosphatidylethanol was formed during stimulation with 100nM 12-0-tetradecanoylphorbol-13-acetate (TPA), when ethanol was present in the culture medium. After 30 minutes of stimulation, phosphatidylethanol constituted 2.6% of the [3H]-glycerol-labelled lipids. Stimulating the cells with TPA in the absence of ethanol caused a significant increase in labelled phosphatidic acid. This increase was inhibited by ethanol. The present findings demonstrate that TPA stimulates phospholipase D activity in cultured C-6 glioma cells.

Synthesis and action of nitric oxide in rat glomerular mesangial cells

1991 ◽  
Vol 261 (4) ◽  
pp. F600-F606 ◽  
Author(s):  
P. J. Shultz ◽  
M. A. Tayeh ◽  
M. A. Marletta ◽  
L. Raij
Keyword(s):  
Nitric Oxide ◽  
Culture Medium ◽  
Mesangial Cells ◽  
Culture Media ◽  
Degradation Products ◽  
Specific Inhibitor ◽  
Cgmp Level ◽  
Glomerular Mesangial Cells ◽  
Intracellular Cgmp ◽  
Stimulation Of

Macrophages and certain tumor cell lines can be induced to synthesize nitric oxide (NO) from L-arginine after stimulation with lipopolysaccharide (LPS) or cytokines. In the present study, we have found that culture medium collected after 24 h from unstimulated rat mesangial cells (MC) contains 6.3 +/- 1.2 microM of NO3-/NO2- (the degradation products of NO). These levels were significantly increased when MC were incubated with LPS (10 micrograms/ml) for 24 h (23.9 +/- 4.1, P less than 0.05). The specific inhibitor of NO synthesis, NG-monomethyl-L-arginine (L-NMMA) completely inhibited LPS-stimulated production of NO3-/NO2-, confirming that the NO3-/NO2- was derived from NO within the MC. Recent studies suggest that endothelium-derived relaxing factor (EDRF) produced by vascular endothelium is also NO, and we have previously shown that both EDRF and NO stimulate increases in MC guanosine 3',5'-cyclic monophosphate (cGMP). Thus we sought to determine whether NO synthesized by the MC could affect cGMP levels within the same cells. After 24-h incubation with LPS (10 micrograms/ml), intracellular cGMP level within the MC was 706.3 +/- 197 (SE) compared with 40.5 +/- 7 fmol/micrograms protein in control MC incubated in media alone (P less than 0.01). The changes in cGMP in response to LPS were inhibited by greater than 90% by L-NMMA. Similar to LPS, incubation of MC with the cytokine gamma-interferon also increased NO3-/NO2- in the culture media and increased cGMP levels within MC. The induction of NO synthesis within MC and the concomitant stimulation of MC cGMP may be important in the modulation of the effects of endotoxemia, as well as inflammation, within the glomerulus.

Activation of Glomerular Mesangial Cells by Hepatocyte Growth Factor Through Tyrosine Kinase and Protein Kinase C

1998 ◽  
Vol 55 (2) ◽  
pp. 227-234 ◽  
Author(s):  
Nicholas J Laping ◽  
Barbara A Olson ◽  
Robin E DeWolf ◽  
Christine R Albrightson ◽  
Todd Fredrickson ◽  
...  
Keyword(s):  
Protein Kinase C ◽  
Growth Factor ◽  
Protein Kinase ◽  
Hepatocyte Growth Factor ◽  
Tyrosine Kinase ◽  
Mesangial Cells ◽  
Glomerular Mesangial Cells ◽  
Kinase C ◽  
Hepatocyte Growth

Phospholipase D: enzymology, mechanisms of regulation, and function

1997 ◽  
Vol 77 (2) ◽  
pp. 303-320 ◽  
Author(s):  
J. H. Exton
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Phosphatidic Acid ◽  
G Protein ◽  
Phospholipase D ◽  
Tyrosine Kinases ◽  
Rho Proteins ◽  
Kinase C

Phospholipase D exists in various forms that differ in their regulation but predominantly hydrolyze phosphatidylcholine. The Ca(2+)-dependent isozymes of protein kinase C regulate phospholipase D in vitro and play a major role in its control by growth factors and G protein-linked agonists in vivo. Recent studies have demonstrated that small G proteins of the ADP-ribosylation factor (ARF) and Rho families activate the enzyme in vitro, and evidence is accumulating that they also are involved in its control in vivo. Both types of G protein play important roles in cellular function, and the possible mechanisms by which they are activated by agonists are discussed. There is also emerging evidence of the control of phospholipase D and Rho proteins by soluble tyrosine kinases and novel serine/threonine kinases. The possible role of these kinases in agonist regulation of phospholipase D is discussed. The function of phospholipase D in cells is still poorly defined. Postulated roles of phosphatidic acid produced by phospholipase D action include the activation of Ca(2+)-independent isoforms of protein kinase C, the regulation of growth and the cytoskeleton in fibroblasts, and control of the respiratory burst in neutrophils. Another important function of phosphatidic acid is to act as a substrate for a specific phospholipase A2 to generate lysophosphatidic acid, which is becoming increasingly recognized as a major intercellular messenger. Finally, it is possible that the phospholipid changes induced in various cellular membranes by phospholipase D may per se play an important role in vesicle trafficking and other membrane-associated events.

Lipid A activation of glomerular mesangial cells: mimicry of the bioactive lipid, phosphatidic acid

1992 ◽  
Vol 262 (2) ◽  
pp. C328-C338 ◽  
Author(s):  
S. L. Bursten ◽  
W. E. Harris ◽  
K. Resch ◽  
D. H. Lovett
Keyword(s):  
Phosphatidic Acid ◽  
Positive Feedback ◽  
Lipid A ◽  
Mesangial Cells ◽  
Biologically Active ◽  
Transferase Activity ◽  
Acyl Transferase ◽  
Glomerular Mesangial Cells ◽  
Cellular Activation ◽  
Acyl Transferase Activity

Lipid A, the active component of bacterial endotoxin, stimulates multiple cell types, including glomerular mesangial cells (MC), and yet the molecular mechanisms of cell activation remain unclear. Lipid A, in its monosaccharyl form, structurally resembles the biologically active lipid phosphatidic acid (PA). Given this, it was postulated that lipid A activates cells by acting as a structural and functional mimetic of PA. Lipid A was found to specifically stimulate an MC lyso-PA acyl transferase activity, leading to enhanced synthesis of sn-2-unsaturated forms of PA. Sn-2-unsaturated PA itself, in contrast to sn-2-saturated PA, also stimulated the lyso-PA acyl transferase activity, a positive feedback feature previously noted with lyso-lecithin acyl transferase. Structure-function correlations demonstrated that the phosphate moieties in both PA and lipid A were necessary to feedback stimulation of lyso-PA acyl transferase (AT), as dephosphorylated lipid A and 2-unsaturated 1,2-sn-diacylglycerol had no stimulatory effect on lyso-PA AT. The biologic relevance of the lipid A and PA-mediated increases in lyso-PA acyl transferase activity was shown, whereby limited exposure to these lipids rapidly induced identical MC morphologic and functional alterations characteristic of cellular activation. By mimicking the stimulatory action of PA, per se, on lyso-PA acyl transferase activity, lipid A may initiate a positive feedback cycle of acylation, yielding increased amounts of PA enriched in unsaturated fatty acids. This newly synthesized PA may subsequently act as the proximal mediator of cellular activation.

Mechanical stretch/relaxation of cultured rat mesangial cells induces protooncogenes and cyclooxygenase

1994 ◽  
Vol 267 (2) ◽  
pp. C482-C490 ◽  
Author(s):  
Y. Akai ◽  
T. Homma ◽  
K. D. Burns ◽  
T. Yasuda ◽  
K. F. Badr ◽  
...  
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Mesangial Cells ◽  
Calcium Influx ◽  
Regulation Of Gene Expression ◽  
Calcium Content ◽  
Mechanical Stretch ◽  
Glomerular Mesangial Cells ◽  
Cell Functions ◽  
Kinase C

In cultured rat glomerular mesangial cells, continuous cycles of stretching and relaxation (stretch/relaxation) stimulate cell proliferation, protein synthesis, and prostaglandin production. We examined regulation of gene expression that may underlie these alterations in cell functions. Stretch/relaxation caused time-dependent induction of the immediate early genes, c-fos and zif 268/egr-1, with maximal increases occurring between 15 and 30 min. The mitogen-inducible prostaglandin G2/H2 synthase (PGH2S-2) gene was also induced within 30 min of stretch/relaxation, with concomitant increases in the immunoreactive PGH2S-2 protein. These gene inductions were preceded by transient translocation of protein kinase C activity from cytosol to membrane as well as by increases in 45Ca2+ uptake and total cellular calcium content. The stretch/relaxation-induced expression was suppressed by protein kinase C inhibition, whereas less profound inhibition was observed with inhibition of calcium influx in low (100 nM) calcium buffer. These findings indicate that in mesangial cells mechanical stress induces expression of the protooncogenes and the mitogen-inducible cyclooxygenase primarily through protein kinase C-dependent mechanisms.

scholarly journals Mesangial cell proteoglycans: synthesis and metabolism.

1992 ◽  
Vol 2 (10) ◽  
pp. S88
Author(s):  
M Davies ◽  
G J Thomas ◽  
L D Shewring ◽  
R M Mason
Keyword(s):  
Culture Medium ◽  
Mesangial Cell ◽  
Dermatan Sulfate ◽  
Mesangial Cells ◽  
Core Protein ◽  
Glomerular Mesangial Cells ◽  
Cellular Processes ◽  
Specialized Function ◽  
In Cells

In cultures of human adult glomerular mesangial cells, large chondroitin sulfate proteoglycans (CSPG) and small dermatan sulfate proteoglycans (DSPG) are synthesized. The large CSPG has a core protein, M(r) of 400,000 (major) and M(r) of 500,000 (minor), and binds to hyaluronic acid to form large aggregates. The two small DSPGs (Mr of approximately 350,000 and M(r) of approximately 200,000) were related to biglycan and decorin, respectively. The majority of these proteoglycans were located in the culture medium, but a hydrophobic form of the CSPG was extracted from the cell layer. Mesangial cells in the growing phase synthesized and secreted all three types of proteoglycans, but in cells arrested in G0 by serum deprivation the incorporation of (35S)sulfate in CSPG was drastically reduced. In the same cells stimulated to proliferate by replacing the medium with one containing serum, the synthesis of CSPG dramatically enhanced. The synthesis of CSPG and DSPG was also elevated in cells cocultured with cytokines but in contrast was significantly reduced when cultured in medium containing hyperglycemic levels of glucose. Finally, preliminary experiments are reported that indicate that CSPG and DSPG bind to low-density lipoproteins in vitro. These observations suggest a possible specialized function for proteoglycans in cellular processes characteristic of glomerular disease.

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