Enhancement of autophagy by simvastatin through inhibition of Rac1-mTOR signaling pathway in coronary arterial myocytes

Yu Miao Wei, Xiang Li, Ming Xu, Justine M. Abais, Yang Chen, Christopher R. Riebling, Krishna M. Boini, Pin Lan Li, Yang Zhang

Research output: Contribution to journalArticle

Abstract

Background/Aims: In addition to their action of lowering blood cholesterol levels, statins modulate biological characteristics and functions of arterial myocytes such as viability, proliferation, apoptosis, survival and contraction. The present study tested whether simvastatin, as a prototype statin, enhances autophagy in coronary arterial myocytes (CAMs) to thereby exert their beneficial effects in atherosclerosis. Methods and Results: Using flow cytometry, we demonstrated that simvastatin significantly increased the autophagsome formation in CAMs. Western blot analysis confirmed that simvastatin significantly increased protein expression of typical autophagy markers LC3B and Beclin1 in these CAMs. Confocal microscopy further demonstrated that simvastatin increased fusion of autophagosomes with lysosomes, which was blocked by autophagy inhibitor 3-methyladenine or silencing of Atg7 genes. Simvastatin reduced mammalian target of rapamycin (mTOR) activity, which was reversed by Rac1-GTPase overexpression and the mTOR agonist phosphatidic acid. Moreover, both Rac1-GTPase overexpression and activation of mTOR by phosphatidic acid drastically blocked simvastatin-induced autophagosome formation in CAMs. Interestingly, simvastatin increased protein expression of a contractile phenotype marker calponin in CAMs, which was blocked by autophagy inhibitor 3-methyladenine. Simvastatin markedly reduced proliferation of CAMs under both control and proatherogenic stimulation. However, this inhibitory effect of simvastatin on CAM proliferation was blocked by by autophagy inhibitor 3-methyladenine or silencing of Atg7 genes. Lastly, animal experiments demonstrated that simvastatin increased protein expression of LC3B and calponin in mouse coronary arteries. Conclusion: Our results indicate that simvastatin inhibits the Rac1-mTOR pathway and thereby increases autophagy in CAMs which may stabilize CAMs in the contractile phenotype to prevent proliferation and growth of these cells.

Original languageEnglish (US)
Pages (from-to)925-937
Number of pages13
JournalCellular Physiology and Biochemistry
Volume31
Issue number6
DOIs
StatePublished - Jul 2013
Externally publishedYes

Fingerprint

Simvastatin
Autophagy
Sirolimus
Muscle Cells
Hydroxymethylglutaryl-CoA Reductase Inhibitors
Phosphatidic Acids
GTP Phosphohydrolases
Gene Silencing
Phenotype
Proteins
Lysosomes
Confocal Microscopy
Atherosclerosis
Coronary Vessels
Flow Cytometry
Western Blotting
Cholesterol
Cell Proliferation
Apoptosis

Keywords

  • Atherosclerosis
  • Autophagy
  • Coronary arterial myocyte
  • mTOR
  • Simvastatin

ASJC Scopus subject areas

  • Physiology

Cite this

Enhancement of autophagy by simvastatin through inhibition of Rac1-mTOR signaling pathway in coronary arterial myocytes. / Wei, Yu Miao; Li, Xiang; Xu, Ming; Abais, Justine M.; Chen, Yang; Riebling, Christopher R.; Boini, Krishna M.; Li, Pin Lan; Zhang, Yang.

In: Cellular Physiology and Biochemistry, Vol. 31, No. 6, 07.2013, p. 925-937.

Research output: Contribution to journalArticle

Wei, YM, Li, X, Xu, M, Abais, JM, Chen, Y, Riebling, CR, Boini, KM, Li, PL & Zhang, Y 2013, 'Enhancement of autophagy by simvastatin through inhibition of Rac1-mTOR signaling pathway in coronary arterial myocytes', Cellular Physiology and Biochemistry, vol. 31, no. 6, pp. 925-937. https://doi.org/10.1159/000350111
Wei, Yu Miao ; Li, Xiang ; Xu, Ming ; Abais, Justine M. ; Chen, Yang ; Riebling, Christopher R. ; Boini, Krishna M. ; Li, Pin Lan ; Zhang, Yang. / Enhancement of autophagy by simvastatin through inhibition of Rac1-mTOR signaling pathway in coronary arterial myocytes. In: Cellular Physiology and Biochemistry. 2013 ; Vol. 31, No. 6. pp. 925-937.
@article{36c058c015964413b61764b6b06bbd03,
title = "Enhancement of autophagy by simvastatin through inhibition of Rac1-mTOR signaling pathway in coronary arterial myocytes",
abstract = "Background/Aims: In addition to their action of lowering blood cholesterol levels, statins modulate biological characteristics and functions of arterial myocytes such as viability, proliferation, apoptosis, survival and contraction. The present study tested whether simvastatin, as a prototype statin, enhances autophagy in coronary arterial myocytes (CAMs) to thereby exert their beneficial effects in atherosclerosis. Methods and Results: Using flow cytometry, we demonstrated that simvastatin significantly increased the autophagsome formation in CAMs. Western blot analysis confirmed that simvastatin significantly increased protein expression of typical autophagy markers LC3B and Beclin1 in these CAMs. Confocal microscopy further demonstrated that simvastatin increased fusion of autophagosomes with lysosomes, which was blocked by autophagy inhibitor 3-methyladenine or silencing of Atg7 genes. Simvastatin reduced mammalian target of rapamycin (mTOR) activity, which was reversed by Rac1-GTPase overexpression and the mTOR agonist phosphatidic acid. Moreover, both Rac1-GTPase overexpression and activation of mTOR by phosphatidic acid drastically blocked simvastatin-induced autophagosome formation in CAMs. Interestingly, simvastatin increased protein expression of a contractile phenotype marker calponin in CAMs, which was blocked by autophagy inhibitor 3-methyladenine. Simvastatin markedly reduced proliferation of CAMs under both control and proatherogenic stimulation. However, this inhibitory effect of simvastatin on CAM proliferation was blocked by by autophagy inhibitor 3-methyladenine or silencing of Atg7 genes. Lastly, animal experiments demonstrated that simvastatin increased protein expression of LC3B and calponin in mouse coronary arteries. Conclusion: Our results indicate that simvastatin inhibits the Rac1-mTOR pathway and thereby increases autophagy in CAMs which may stabilize CAMs in the contractile phenotype to prevent proliferation and growth of these cells.",
keywords = "Atherosclerosis, Autophagy, Coronary arterial myocyte, mTOR, Simvastatin",
author = "Wei, {Yu Miao} and Xiang Li and Ming Xu and Abais, {Justine M.} and Yang Chen and Riebling, {Christopher R.} and Boini, {Krishna M.} and Li, {Pin Lan} and Yang Zhang",
year = "2013",
month = "7",
doi = "10.1159/000350111",
language = "English (US)",
volume = "31",
pages = "925--937",
journal = "Cellular Physiology and Biochemistry",
issn = "1015-8987",
publisher = "S. Karger AG",
number = "6",

}

TY - JOUR

T1 - Enhancement of autophagy by simvastatin through inhibition of Rac1-mTOR signaling pathway in coronary arterial myocytes

AU - Wei, Yu Miao

AU - Li, Xiang

AU - Xu, Ming

AU - Abais, Justine M.

AU - Chen, Yang

AU - Riebling, Christopher R.

AU - Boini, Krishna M.

AU - Li, Pin Lan

AU - Zhang, Yang

PY - 2013/7

Y1 - 2013/7

N2 - Background/Aims: In addition to their action of lowering blood cholesterol levels, statins modulate biological characteristics and functions of arterial myocytes such as viability, proliferation, apoptosis, survival and contraction. The present study tested whether simvastatin, as a prototype statin, enhances autophagy in coronary arterial myocytes (CAMs) to thereby exert their beneficial effects in atherosclerosis. Methods and Results: Using flow cytometry, we demonstrated that simvastatin significantly increased the autophagsome formation in CAMs. Western blot analysis confirmed that simvastatin significantly increased protein expression of typical autophagy markers LC3B and Beclin1 in these CAMs. Confocal microscopy further demonstrated that simvastatin increased fusion of autophagosomes with lysosomes, which was blocked by autophagy inhibitor 3-methyladenine or silencing of Atg7 genes. Simvastatin reduced mammalian target of rapamycin (mTOR) activity, which was reversed by Rac1-GTPase overexpression and the mTOR agonist phosphatidic acid. Moreover, both Rac1-GTPase overexpression and activation of mTOR by phosphatidic acid drastically blocked simvastatin-induced autophagosome formation in CAMs. Interestingly, simvastatin increased protein expression of a contractile phenotype marker calponin in CAMs, which was blocked by autophagy inhibitor 3-methyladenine. Simvastatin markedly reduced proliferation of CAMs under both control and proatherogenic stimulation. However, this inhibitory effect of simvastatin on CAM proliferation was blocked by by autophagy inhibitor 3-methyladenine or silencing of Atg7 genes. Lastly, animal experiments demonstrated that simvastatin increased protein expression of LC3B and calponin in mouse coronary arteries. Conclusion: Our results indicate that simvastatin inhibits the Rac1-mTOR pathway and thereby increases autophagy in CAMs which may stabilize CAMs in the contractile phenotype to prevent proliferation and growth of these cells.

AB - Background/Aims: In addition to their action of lowering blood cholesterol levels, statins modulate biological characteristics and functions of arterial myocytes such as viability, proliferation, apoptosis, survival and contraction. The present study tested whether simvastatin, as a prototype statin, enhances autophagy in coronary arterial myocytes (CAMs) to thereby exert their beneficial effects in atherosclerosis. Methods and Results: Using flow cytometry, we demonstrated that simvastatin significantly increased the autophagsome formation in CAMs. Western blot analysis confirmed that simvastatin significantly increased protein expression of typical autophagy markers LC3B and Beclin1 in these CAMs. Confocal microscopy further demonstrated that simvastatin increased fusion of autophagosomes with lysosomes, which was blocked by autophagy inhibitor 3-methyladenine or silencing of Atg7 genes. Simvastatin reduced mammalian target of rapamycin (mTOR) activity, which was reversed by Rac1-GTPase overexpression and the mTOR agonist phosphatidic acid. Moreover, both Rac1-GTPase overexpression and activation of mTOR by phosphatidic acid drastically blocked simvastatin-induced autophagosome formation in CAMs. Interestingly, simvastatin increased protein expression of a contractile phenotype marker calponin in CAMs, which was blocked by autophagy inhibitor 3-methyladenine. Simvastatin markedly reduced proliferation of CAMs under both control and proatherogenic stimulation. However, this inhibitory effect of simvastatin on CAM proliferation was blocked by by autophagy inhibitor 3-methyladenine or silencing of Atg7 genes. Lastly, animal experiments demonstrated that simvastatin increased protein expression of LC3B and calponin in mouse coronary arteries. Conclusion: Our results indicate that simvastatin inhibits the Rac1-mTOR pathway and thereby increases autophagy in CAMs which may stabilize CAMs in the contractile phenotype to prevent proliferation and growth of these cells.

KW - Atherosclerosis

KW - Autophagy

KW - Coronary arterial myocyte

KW - mTOR

KW - Simvastatin

UR - http://www.scopus.com/inward/record.url?scp=84879495351&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84879495351&partnerID=8YFLogxK

U2 - 10.1159/000350111

DO - 10.1159/000350111

M3 - Article

C2 - 23817226

AN - SCOPUS:84879495351

VL - 31

SP - 925

EP - 937

JO - Cellular Physiology and Biochemistry

JF - Cellular Physiology and Biochemistry

SN - 1015-8987

IS - 6

ER -