Involvement of PDGF in pressure-induced mesangial cell proliferation through PKC and tyrosine kinase pathways

1999 ◽  
Vol 277 (1) ◽  
pp. F105-F112 ◽  
Author(s):  
Hiroaki Kato ◽  
Akihiko Osajima ◽  
Yasuhito Uezono ◽  
Masahiro Okazaki ◽  
Yuki Tsuda ◽  
...  

In glomerular hypertension, mesangial cells (MC) are subjected to at least two physical forces: mechanical stretch and high transmural pressure. Increased transmural pressure, as well as mechanical stretch, promotes MC proliferation, which may enhance glomerulosclerosis. The exact mechanism of this effect is not fully understood. We examined the effects of transmural pressure alone on cell proliferation and DNA synthesis and investigated the role of platelet-derived growth factor (PDGF) and basic fibroblast growth factor (bFGF), candidates for mediation of glomerular diseases, in the pressure-induced events. Pressure was applied to cultured MC placed in a sealed chamber using compressed helium gas. Application of pressure resulted in a time-dependent (∼2 h) and pressure level-dependent (∼80 mmHg) increase in cell number (1.4-fold) and [3H]thymidine incorporation (2.7-fold). Pressure-induced DNA synthesis was significantly suppressed by inhibitors of phospholipase C (2-nitro-4-carboxyphenyl- N, N-diphenylcarbamate), protein kinase C [1-(5-isoquinolinylsulfonyl)-2-methylpiperazine and chelerythrine], or tyrosine kinases (genistein). Pressure caused a rapid but transient formation of inositol 1,4,5-trisphosphate, which was blocked by the phospholipase C inhibitor. Pressure also promoted a rapid increase in tyrosine kinase activity. Pressure increased mRNA levels of PDGF-B, with a peak at 6 h, but not those of PDGF-A or bFGF. Pressure-induced DNA synthesis was partially inhibited by a neutralizing anti-PDGF antibody but not by an antibody against bFGF or nonimmune IgG. Our results indicated that pressure by itself increases DNA synthesis and proliferation of cultured rat MC possibly through activation of protein kinase C and tyrosine kinases, and PDGF-B could be partially involved in these pathways.

1998 ◽  
Vol 55 (2) ◽  
pp. 227-234 ◽  
Author(s):  
Nicholas J Laping ◽  
Barbara A Olson ◽  
Robin E DeWolf ◽  
Christine R Albrightson ◽  
Todd Fredrickson ◽  
...  

2000 ◽  
Vol 350 (2) ◽  
pp. 413-419 ◽  
Author(s):  
Luz DEL CARMEN MEDINA ◽  
José VÁZQUEZ-PRADO ◽  
J. Adolfo GARCÍA-SÁINZ

The effect of epidermal growth factor (EGF) and platelet-derived growth factor (PDGF) on the phosphorylation and function of α1b-adrenoceptors transfected into Rat-1 fibroblasts was studied. EGF and PDGF increased the phosphorylation of these adrenoceptors. The effect of EGF was blocked by tyrphostin AG1478 and that of PDGF was blocked by tyrphostin AG1296, inhibitors of the intrinsic tyrosine kinase activities of the receptors for these growth factors. Wortmannin, an inhibitor of phosphoinositide 3-kinase, blocked the α1b-adrenoceptor phosphorylation induced by EGF but not that induced by PDGF. Inhibition of protein kinase C blocked the adrenoceptor phosphorylation induced by EGF and PDGF. The ability of noradrenaline to increase [35S]guanosine 5´-[γ-thio]triphosphate ([35S]GTP[S]) binding in membrane preparations was used as an index of the functional coupling of the α1b-adrenoceptors and G-proteins. Noradrenaline-stimulated [35S]GTP[S] binding was markedly decreased in membranes from cells pretreated with EGF or PDGF. Our data indicate that: (i) activation of EGF and PDGF receptors induces phosphorylation of α1b-adrenoceptors, (ii) phosphatidylinositol 3-kinase is involved in the EGF response, but does not seem to play a major role in the action of PDGF, (iii) protein kinase C mediates this action of both growth factors and (iv) the phosphorylation of α1b-adrenoceptors induced by EGF and PDGF is associated with adrenoceptor desensitization.


1991 ◽  
Vol 2 (9) ◽  
pp. 719-726 ◽  
Author(s):  
M Presta ◽  
L Tiberio ◽  
M Rusnati ◽  
P Dell'Era ◽  
G Ragnotti

Basic fibroblast growth factor (bFGF) induces a protein kinase C (PKC)-dependent mitogenic response in transformed fetal bovine aortic endothelial GM 7373 cells. A long-lasting interaction of bFGF with the cell is required to induce cell proliferation. bFGF-treated cells are in fact committed to proliferate only after they have entered the phase S of the cell cycle, 12-14 h after the beginning of bFGF treatment. Before that time, the mitogenic response to bFGF is abolished by 1) removal of extracellular bFGF by suramin, 2) addition of neutralizing anti-bFGF antibodies to the culture medium, 3) inhibition of PKC activity by the protein kinase inhibitor H-7, and 4) down-regulation of PKC by cotreatment with phorbol ester. Thus the requirement for a prolonged interaction of bFGF with the cell reflects the requirement for a prolonged activation of PKC. Similar conclusions can be drawn for the PKC activators 12-O-tetradecanoyl phorbol 13-acetate and 1,2-dioctanoyl-sn-glycerol. The two molecules require 16 and 6 h, respectively, of activation of PKC to induce 50% of maximal cell proliferation. The requirement for a long-lasting activation of PKC appears to be a mechanism for the control of cell proliferation capable of discriminating among transient nonmitogenic stimuli and long-lasting mitogenic stimuli.


1990 ◽  
Vol 73 (1) ◽  
pp. 98-105 ◽  
Author(s):  
Ian F. Pollack ◽  
Margaret S. Randall ◽  
Matthew P. Kristofik ◽  
Robert H. Kelly ◽  
Robert G. Selker ◽  
...  

✓ To evaluate the role of protein kinase C-mediated pathways in the proliferation of malignant gliomas, this study examined the effect of a protein kinase C (PKC)-activating phorbol ester (12-O-tetradecanoyl-13-phorbol acetate or TPA) and a protein kinase C inhibitor (polymyxin B) on deoxyribonucleic acid (DNA) synthesis of malignant glioma cells in vitro. A serum-free chemically defined medium, MCDB 105, was employed for all studies. Two established human malignant glioma cell lines (T98G and U138), two rat glioma lines (9L and C6), and two low-passage human glioma lines (obtained from surgical specimens) were studied. With the exception of the C6 line, all tumors responded in a dose-dependent fashion to nanomolar concentrations of TPA with a median effective dose that varied from 0.5 ng/ml for the U138 glioma to 1 ng/ml for the T98G glioma. At optimal concentrations (5 to 10 ng/ml), TPA produced a two- to five-fold increase in the rate of DNA synthesis (p < 0.05) as assessed by incorporation of 3H-thymidine. However, TPA had no additive effect on the mitogenic response produced by epidermal growth factor (EGF) or platelet-derived growth factor (PDGF). Inhibition of PKC using the antibiotic polymyxin B (20 µg/ml) abolished the TPA-induced mitogenic response in the five responsive lines tested. In two tumors (U138 and 9L), polymyxin B also eliminated EGF-, PDGF-, and serum-induced DNA synthesis as well as abolishing baseline DNA synthesis. These cells remained viable, however, as assessed by trypan blue exclusion; after removal of polymyxin B from the medium, they were able to resume DNA synthesis in response to TPA and serum. In the three other tumors (T98G and the two low-passage human glioma lines), growth factor-induced and serum-induced DNA synthesis were inhibited by approximately 25% to 85%. It is concluded that PKC-mediated pathways affect DNA synthesis in the human malignant glial tumors studied. The response of the glioma cells to TPA is similar to the responses seen in fetal astrocytes, but differs significantly from those reported for normal adult glial cultures. Because the response of the 9L glioma to TPA is similar to the responses seen in the human tumors, the 9L rat glioma model may prove useful for examining the role of PKC-mediated pathways in controlling glioma growth in vivo.


1988 ◽  
Vol 8 (8) ◽  
pp. 3345-3356 ◽  
Author(s):  
K L Gould ◽  
T Hunter

We have shown previously that pp60c-src is a substrate for protein kinase C in vivo and that the target of protein kinase C phosphorylation in mammalian pp60c-src is serine 12. We now demonstrate that in addition to tumor promoters, all activators of phosphatidylinositol turnover that we have tested in fibroblasts (platelet-derived growth factor, fibroblast growth factor, serum, vasopressin, sodium orthovanadate, and prostaglandin F2 alpha) lead to the phosphorylation of pp60c-src at serine 12. In addition to stimulating serine 12 phosphorylation in pp60c-src, platelet-derived growth factor treatment of quiescent fibroblasts induces phosphorylation of one or two additional serine residues and one tyrosine residue within the N-terminal 16 kilodaltons of the enzyme and activates its immune complex protein-tyrosine kinase activity.


1994 ◽  
Vol 143 (2) ◽  
pp. 221-226 ◽  
Author(s):  
T Takano ◽  
K Takada ◽  
H Tada ◽  
S Nishiyama ◽  
N Amino

Abstract Long-term administration of lithium is one of the well-known causes of goiter. It can stimulate DNA synthesis in rat thyroid cells (FRTL-5) treated with thyroid-stimulating hormone (TSH). To investigate the mitogenic signal transduction system activated by lithium, lithium-induced DNA synthesis and Ca2+ influx were studied using two protein kinase inhibitors, genistein as a specific tyrosine kinase inhibitor and staurosporine as a potent inhibitor of protein kinase C. Genistein but not staurosporine blocked the DNA synthesis induced by lithium in TSH-primed cells but neither compound had any effect on the Ca2+ entry stimulated by lithium. Genistein clearly attenuated the phosphotyrosine content of the 175 kDa substrate in the presence of lithium but staurosporine failed to do so. Moreover, lithium could also stimulate DNA synthesis in protein kinase C down-regulated cells. These data demonstrate that lithium may require the activation of a particular genistein-sensitive kinase, possibly a tyrosine kinase, to induce cell proliferation. It is suggested that the phorbol ester-sensitive protein kinase C family might not participate in the mitogenic signal transduction pathway activated by lithium. Journal of Endocrinology (1994) 143, 221–226


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