Knockdown of AMPKα2 Promotes Pulmonary Arterial Smooth Muscle Cells Proliferation via mTOR/Skp2/p27(Kip1) Signaling Pathway.
It has been shown that activation of adenosine monophosphate-activated protein kinase (AMPK) suppresses proliferation of a variety of tumor cells as well as nonmalignant cells. In this study, we used post-transcriptional gene silencing with small interfering RNA (siRNA) to specifically examine the effect of AMPK on pulmonary arterial smooth muscle cells (PASMCs) proliferation and to further elucidate its underlying molecular mechanisms. Our results showed that knockdown of AMPKα2 promoted primary cultured PASMCs proliferation; this was accompanied with the elevation of phosphorylation of mammalian target of rapamycin (mTOR) and S-phase kinase-associated protein 2 (Skp2) protein level and reduction of p27(Kip1). Importantly, prior silencing of mTOR with siRNA abolished AMPKα2 knockdown-induced Skp2 upregulation, p27(Kip1) reduction as well as PASMCs proliferation. Furthermore, pre-depletion of Skp2 by siRNA also eliminated p27(Kip1) downregulation and PASMCs proliferation caused by AMPKα2 knockdown. Taken together, our study indicates that AMPKα2 isoform plays an important role in regulation of PASMCs proliferation by modulating mTOR/Skp2/p27(Kip1) axis, and suggests that activation of AMPKα2 might have potential value in the prevention and treatment of pulmonary arterial hypertension.
Department of Respiratory and Critical Care Medicine, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an 710061, China. ke19870912@163.com.
Rui
R
Ke
Department of Respiratory and Critical Care Medicine, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an 710061, China. liulu290@126.com.
Lu
L
Liu
Department of Respiratory and Critical Care Medicine, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an 710061, China. zhuyanting0816@163.com.
Yanting
Y
Zhu
Department of Respiratory and Critical Care Medicine, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an 710061, China. wdm19870914@163.com.
Shaojun
S
Li
Department of Respiratory and Critical Care Medicine, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an 710061, China. xiexinming1986@163.com.
Xinming
X
Xie
Department of Respiratory and Critical Care Medicine, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an 710061, China. lifangwei80@163.com.
Fangwei
F
Li
Department of Respiratory and Critical Care Medicine, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an 710061, China. wyshzl@163.com.
Yang
Y
Song
Department of Respiratory and Critical Care Medicine, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an 710061, China. yanglanmed@163.com.
Lan
L
Yang
Division of Allergy and Clinical Immunology, Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, MD 21224, USA. lgao2@jhmi.edu.
Li
L
Gao
Department of Respiratory and Critical Care Medicine, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an 710061, China. manxiangli@hotmail.com.
Manxiang
M
Li
D055372:AMP-Activated Protein Kinases / Q000235:genetics*; D000818:Animals; D049109:Cell Proliferation; D002478:Cells, Cultured; D050760:Cyclin-Dependent Kinase Inhibitor p27 / Q000378:metabolism; D055785:Gene Knockdown Techniques / Q000379:methods*; D009131:Muscle, Smooth, Vascular / Q000166:cytology*; D032389:Myocytes, Smooth Muscle / Q000166:cytology*; D010766:Phosphorylation; D011651:Pulmonary Artery / Q000166:cytology*; D051381:Rats; D044786:S-Phase Kinase-Associated Proteins / Q000378:metabolism; D015398:Signal Transduction; D058570:TOR Serine-Threonine Kinases / Q000378:metabolism
C493962:Cdkn1b protein, rat; D044786:S-Phase Kinase-Associated Proteins; D050760:Cyclin-Dependent Kinase Inhibitor p27; C546845:mTOR protein, rat; C543928:Prkaa2 protein, rat; D058570:TOR Serine-Threonine Kinases; D055372:AMP-Activated Protein Kinases
AMPK; Skp2; mTOR; proliferation; pulmonary arterial smooth muscle cells