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.

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

Mesangial cell-reduced Ca2+ signaling in high glucose is due to inactivation of phospholipase C-β3 by protein kinase C

2005 ◽  
Vol 289 (5) ◽  
pp. F1078-F1087 ◽  
Author(s):  
Helena Frecker ◽  
Snezana Munk ◽  
Hong Wang ◽  
Catharine Whiteside
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Phospholipase C ◽  
High Glucose ◽  
Mesangial Cells ◽  
Fold Increase ◽  
Glomerular Mesangial Cells ◽  
Kinase C ◽  
Normal Glucose ◽  
Intracellular Ca

In high glucose, glomerular mesangial cells (MCs) demonstrate impaired Ca2+ signaling in response to seven-transmembrane receptor stimulation. To identify the mechanism, we first postulated decreased release from intracellular stores. Intracellular Ca2+ was measured in fluo-3-loaded primary cultured rat MCs using confocal fluorescence microscopy. In high glucose (HG) 30 mM for 48 h, the 25 nM ionomycin-stimulated intracellular Ca2+ response was reduced to 82% of that observed in normal glucose (NG). In NG 5.6 mM, Ca2+ responses to endothelin (ET)-1 and platelet-derived growth factor (PDGF) were unchanged in cells cultured in 50 nM Ca2+ vs. 1.8 mM Ca2+. Depletion of intracellular Ca2+ stores with thapsigargin eliminated ET-1-stimulated Ca2+ responses. Incubation in 30 mM glucose (HG) for 48 h or stimulation with phorbol myristate acetate (PMA) for 10 min eliminated the Ca2+ response to ET-1 but had no effect on the PDGF response. Downregulation of protein kinase C (PKC) with 24-h PMA or inhibition with Gö6976 in HG normalized the Ca2+ response to ET-1. Because ET-1 and PDGF stimulate Ca2+ signaling through different phospholipase C pathways, we hypothesized that, in HG, PKC selectively phosphorylates and inhibits PLC-β3. Using confocal immunofluorescence imaging, in NG, a 1.6- to 1.7-fold increase in PLC-β3 Ser1105 phosphorylation was observed following PMA or ET-1 stimulation for 10 min. In HG, immunofluorescent imaging and immunoblotting showed increased PLC-β3 phosphorylation, without change in total PLC-β3, which was reversed with 24-h PMA or Gö6976. We conclude that reduced Ca2+ signaling in HG cannot be explained by reduced Ca2+ stores but is due to conventional PKC-dependent phosphorylation and inactivation of PLC-β3.

scholarly journals Regulation of capacitative calcium influx in cultured human mesangial cells: roles of protein kinase C and calmodulin.

1996 ◽  
Vol 7 (7) ◽  
pp. 983-990
Author(s):  
P Menè ◽  
F Pugliese ◽  
G A Cinotti
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Mesangial Cells ◽  
Calcium Influx ◽  
Resting Cells ◽  
Cellular Mechanisms ◽  
Direct Role ◽  
Human Mesangial Cells ◽  
Kinase C

Sustained Ca2+ influx follows discharge of intracellularly stored Ca2+ in a variety of cell types previously equilibrated in Ca(2+)-free media, including cultured human mesangial cells. This Ca2+ influx pathway has been referred to as capacitative Ca2+ entry or Ca2+ release-activated Ca2+ influx (iCRAC). This study investigated two cellular mechanisms potentially controlling iCRAC in human mesangial cells, protein kinase C (PKC), a key signalling kinase activated by vasoconstrictors that release Ca2+ from internal stores, and calmodulin, a Ca(2+)-binding protein that may couple Ca2+ release to the putative channel(s). The PKC activator phorbol myristate acetate (PMA) dose-dependently inhibited both Ca2+ influx in resting cells and iCRAC, assessed by microfluorometry in fura-2-loaded monolayers, when added before or after 1 uM angiotensin II (AngII) (Ca2+ influx at 1 mM (Ca2+)e +278 +/- 56%/+80 +/- 8%, at 10 mM + 473 +/- 59%/+250 +/- 24% (Ca2+)e, -/+ PMA, respectively, P < 0.05). PMA did not affect 5 uM ionomycin-induced iCRAC, possibly because it downregulated Ca2+ release by AngII but not by ionomycin, suggesting a key role of released Ca2+ in triggering subsequent Ca2+ influx. This was confirmed by buffering the (Ca2+)i elevation induced by AngII with intracellularly trapped 1,2-bis-(0-Aminophenoxy)-ethane-N,N,N',N'-tetraacetic acid (BAPTA), which abolished any subsequent iCRAC. Moreover, the calmodulin inhibitors calmidazolium (10 uM), trifluoperazine (0.1 mM), or W-7 (0.1 mM) significantly inhibited AngII- or ionomycin-activated iCRAC (+106 +/- 38/229 +/- 53, +58 +/- 9/195 +/- 29, +161 +/- 38/180 +/- 40% at 1/10 mM (Ca2+)e, all P < 0.05), but did not affect basal Ca2+ entry, consistent with a direct role of cytoplasmic Ca2+ in the regulation of ion gating. These results indicate that iCRAC is under the control of both PKC and calmodulin, and that the site of regulation is distal to the emptying of Ca2+ stores. iCRAC may represent a key mechanism for the control of Ca(2+)-regulated mesangial functions.

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