Mitogenic effect of oxidized low-density lipoprotein on vascular smooth muscle cells mediated by activation of Ras/Raf/MEK/MAPK pathway

C. M. Yang, C. S. Chien, L. D. Hsiao, S. L. Pan, C. C. Wang, C. T. Chiu, C. C. Lin

Research output: Contribution to journalArticle

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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 languageEnglish
Pages (from-to)1531-1541
Number of pages11
JournalBritish Journal of Pharmacology
Volume132
Issue number7
Publication statusPublished - 2001
Externally publishedYes

Fingerprint

Mitogen-Activated Protein Kinase Kinases
Mitogen-Activated Protein Kinases
Vascular Smooth Muscle
Smooth Muscle Myocytes
Mitogen-Activated Protein Kinase 1
Thymidine
Phosphorylation
Cell Proliferation
oxidized low density lipoprotein
Inbred BB Rats
Thapsigargin
Staurosporine
Genistein
Pertussis Toxin
p38 Mitogen-Activated Protein Kinases
G-Protein-Coupled Receptors
Protein-Tyrosine Kinases
Atherosclerosis
Phosphotransferases

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 journalArticle

Yang, C. M. ; Chien, C. S. ; Hsiao, L. D. ; Pan, S. L. ; Wang, C. C. ; Chiu, C. T. ; Lin, C. C. / Mitogenic effect of oxidized low-density lipoprotein on vascular smooth muscle cells mediated by activation of Ras/Raf/MEK/MAPK pathway. In: British Journal of Pharmacology. 2001 ; Vol. 132, No. 7. pp. 1531-1541.
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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

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