Abstract
1. It has been demonstrated that oxidized low-density lipoprotein (OX-LDL) is a risk factor in atherosclerosis by stimulating vascular smooth muscle cell (VSMC) proliferation. However, the mechanisms of OX-LDL-induced cell proliferation are not completely understood. Therefore, we investigated the effect of OX-LDL on cell proliferation associated with mitogen-activated protein kinase (MAPK) activation in rat cultured VSMCs. 2. Both native-LDL (N-LDL) and OX-LDL induced a time- and concentration-dependent incorporation of [ 3H]-thymidine in VSMCs. 3. OX-LDL induced time- and concentration-dependent phosphorylation of p42/p44 MAPK. Pretreatment of these cells with pertussis toxin or U73122 attenuated the OX-LDL-induced responses. 4. Pretreatment with PMA for 24 h, preincubation with a PKC inhibitor staurosporine or the tyrosine kinase inhibitors, genistein and herbimycin A for 1 h, substantially reduced [ 3H]-thymidine incorporation and p42/p44 MAPK phosphorylation induced by OX-LDL. 5. Removal of Ca 2+ by BAPTA/AM or depletion of the internal Ca 2+ pool by thapsigargin significantly inhibited OX-LDL-induced [ 3H]-thymidine incorporation and p42/p44 MAPK phosphorylation. 6. OX-LDL-induced [ 3H]-thymidine incorporation and p42/p44 MAPK phosphorylation was inhibited by PD98059 (an inhibitor of MEK1/2) and SB203580 (an inhibitor of p38 MAPK) in a concentration-dependent manner. 7. Overexpression of dominant negative mutants of Ras (H-Ras-15A) and Raf (Raf-N4) significantly suppressed MEK1/2 and p42/p44 MAPK activation induced by OX-LDL and PDGF-BB, indicating that Ras and Raf may be required for activation of these kinases. 8. These results suggest that the mitogenic effect of OX-LDL is mediated through a PTX-sensitive G protein-coupled receptor that involves the activation of the Ras/Raf/MEK/MAPK pathway similar to that of PDGF-BB in rat cultured VSMCs.
| Original language | English |
|---|---|
| Pages (from-to) | 1531-1541 |
| Number of pages | 11 |
| Journal | British Journal of Pharmacology |
| Volume | 132 |
| Issue number | 7 |
| Publication status | Published - 2001 |
| Externally published | Yes |
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Keywords
- Cell proliferation
- MEK
- Mitogen-activated protein kinase
- Protein kinase C
- Tyrosine kinase
- Vascular smooth muscle cell
ASJC Scopus subject areas
- Pharmacology
Cite this
Mitogenic effect of oxidized low-density lipoprotein on vascular smooth muscle cells mediated by activation of Ras/Raf/MEK/MAPK pathway. / Yang, C. M.; Chien, C. S.; Hsiao, L. D.; Pan, S. L.; Wang, C. C.; Chiu, C. T.; Lin, C. C.
In: British Journal of Pharmacology, Vol. 132, No. 7, 2001, p. 1531-1541.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Mitogenic effect of oxidized low-density lipoprotein on vascular smooth muscle cells mediated by activation of Ras/Raf/MEK/MAPK pathway
AU - Yang, C. M.
AU - Chien, C. S.
AU - Hsiao, L. D.
AU - Pan, S. L.
AU - Wang, C. C.
AU - Chiu, C. T.
AU - Lin, C. C.
PY - 2001
Y1 - 2001
N2 - 1. It has been demonstrated that oxidized low-density lipoprotein (OX-LDL) is a risk factor in atherosclerosis by stimulating vascular smooth muscle cell (VSMC) proliferation. However, the mechanisms of OX-LDL-induced cell proliferation are not completely understood. Therefore, we investigated the effect of OX-LDL on cell proliferation associated with mitogen-activated protein kinase (MAPK) activation in rat cultured VSMCs. 2. Both native-LDL (N-LDL) and OX-LDL induced a time- and concentration-dependent incorporation of [ 3H]-thymidine in VSMCs. 3. OX-LDL induced time- and concentration-dependent phosphorylation of p42/p44 MAPK. Pretreatment of these cells with pertussis toxin or U73122 attenuated the OX-LDL-induced responses. 4. Pretreatment with PMA for 24 h, preincubation with a PKC inhibitor staurosporine or the tyrosine kinase inhibitors, genistein and herbimycin A for 1 h, substantially reduced [ 3H]-thymidine incorporation and p42/p44 MAPK phosphorylation induced by OX-LDL. 5. Removal of Ca 2+ by BAPTA/AM or depletion of the internal Ca 2+ pool by thapsigargin significantly inhibited OX-LDL-induced [ 3H]-thymidine incorporation and p42/p44 MAPK phosphorylation. 6. OX-LDL-induced [ 3H]-thymidine incorporation and p42/p44 MAPK phosphorylation was inhibited by PD98059 (an inhibitor of MEK1/2) and SB203580 (an inhibitor of p38 MAPK) in a concentration-dependent manner. 7. Overexpression of dominant negative mutants of Ras (H-Ras-15A) and Raf (Raf-N4) significantly suppressed MEK1/2 and p42/p44 MAPK activation induced by OX-LDL and PDGF-BB, indicating that Ras and Raf may be required for activation of these kinases. 8. These results suggest that the mitogenic effect of OX-LDL is mediated through a PTX-sensitive G protein-coupled receptor that involves the activation of the Ras/Raf/MEK/MAPK pathway similar to that of PDGF-BB in rat cultured VSMCs.
AB - 1. It has been demonstrated that oxidized low-density lipoprotein (OX-LDL) is a risk factor in atherosclerosis by stimulating vascular smooth muscle cell (VSMC) proliferation. However, the mechanisms of OX-LDL-induced cell proliferation are not completely understood. Therefore, we investigated the effect of OX-LDL on cell proliferation associated with mitogen-activated protein kinase (MAPK) activation in rat cultured VSMCs. 2. Both native-LDL (N-LDL) and OX-LDL induced a time- and concentration-dependent incorporation of [ 3H]-thymidine in VSMCs. 3. OX-LDL induced time- and concentration-dependent phosphorylation of p42/p44 MAPK. Pretreatment of these cells with pertussis toxin or U73122 attenuated the OX-LDL-induced responses. 4. Pretreatment with PMA for 24 h, preincubation with a PKC inhibitor staurosporine or the tyrosine kinase inhibitors, genistein and herbimycin A for 1 h, substantially reduced [ 3H]-thymidine incorporation and p42/p44 MAPK phosphorylation induced by OX-LDL. 5. Removal of Ca 2+ by BAPTA/AM or depletion of the internal Ca 2+ pool by thapsigargin significantly inhibited OX-LDL-induced [ 3H]-thymidine incorporation and p42/p44 MAPK phosphorylation. 6. OX-LDL-induced [ 3H]-thymidine incorporation and p42/p44 MAPK phosphorylation was inhibited by PD98059 (an inhibitor of MEK1/2) and SB203580 (an inhibitor of p38 MAPK) in a concentration-dependent manner. 7. Overexpression of dominant negative mutants of Ras (H-Ras-15A) and Raf (Raf-N4) significantly suppressed MEK1/2 and p42/p44 MAPK activation induced by OX-LDL and PDGF-BB, indicating that Ras and Raf may be required for activation of these kinases. 8. These results suggest that the mitogenic effect of OX-LDL is mediated through a PTX-sensitive G protein-coupled receptor that involves the activation of the Ras/Raf/MEK/MAPK pathway similar to that of PDGF-BB in rat cultured VSMCs.
KW - Cell proliferation
KW - MEK
KW - Mitogen-activated protein kinase
KW - Protein kinase C
KW - Tyrosine kinase
KW - Vascular smooth muscle cell
UR - http://www.scopus.com/inward/record.url?scp=0035067083&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0035067083&partnerID=8YFLogxK
M3 - Article
C2 - 11264247
AN - SCOPUS:0035067083
VL - 132
SP - 1531
EP - 1541
JO - British Journal of Pharmacology
JF - British Journal of Pharmacology
SN - 0007-1188
IS - 7
ER -