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Activation of AMPK by Telmisartan Decreases Basal and PDGF-stimulated VSMC Proliferation via Inhibiting the mTOR/p70S6K Signaling Axis

Title
Activation of AMPK by Telmisartan Decreases Basal and PDGF-stimulated VSMC Proliferation via Inhibiting the mTOR/p70S6K Signaling Axis
Authors
Hwang, Yun-JinPark, Jung-HyunCho, Du-Hyong
Ewha Authors
박정현
SCOPUS Author ID
박정현scopus
Issue Date
2020
Journal Title
JOURNAL OF KOREAN MEDICAL SCIENCE
ISSN
1011-8934JCR Link

1598-6357JCR Link
Citation
JOURNAL OF KOREAN MEDICAL SCIENCE vol. 35, no. 35
Keywords
Vascular Smooth Muscle CellsProliferationAdenosine Monophosphate-activated Protein KinaseMammalian Target of Rapamycinp70 S6 KinaseTelmisartan
Publisher
KOREAN ACAD MEDICAL SCIENCES
Indexed
SCIE; SCOPUS; KCI WOS scopus
Document Type
Article
Abstract
Background: Telmisartan, an angiotensin II type 1 receptor blocker (ARB), is widely used to treat hypertension by blocking the renin-angiotensin-aldosterone system. Although abnormal proliferation of vascular smooth muscle cells (VSMCs) is a well-established contributor to the development of various vascular diseases, such as atherosclerosis, the effect of telmisartan on VSMC proliferation and its mechanism of action have not been fully revealed. Herein, we investigated the molecular mechanism whereby telmisartan inhibits rat VSMC proliferation. Methods: We measured VSMC proliferation by MTT assay, and performed inhibitor studies and western blot analyses using basal and platelet-derived growth factor (PDGF)-stimulated rat VSMCs. To elucidate the role of AMP-activated protein kinase (AMPK), we introduced dominant-negative (dn)-AMPK alpha 1 gene into VSMCs. Results: Telmisartan decreased VSMC proliferation, which was accompanied by decreased phosphorylations of mammalian target of rapamycin (mTOR) at Ser2448 (p-mTOR-Ser(2448)) and p70 S6 kinase (p70S6K) at Thr389 (p-p70S6K-Thr(389)) in doseand time-dependent manners. Telmisartan doseand time-dependently increased phosphorylation of AMPK at Thr172 (p-AMPK-Thr(172)). Co-treatment with compound C, a specific AMPK inhibitor, or ectopic expression of the dn-AMPK alpha 1 gene, significantly reversed telmisartan-inhibited VSMC proliferation, p-mTOR-Ser(2448) and p-p70S6K-Thr(389) levels. Among the ARBs tested (including losartan and fimasartan), only telmisartan increased p-AMPK-Thr(172) and decreased p-mTOR-Ser(2448), p-p70S6K-Thr(389), and VSMC proliferation. Furthermore, GW9662, a specific and irreversible peroxisome proliferator-activated receptor gamma (PPAR gamma) antagonist, did not affect any of the telmisartan-induced changes. Finally, telmisartan also exhibited inhibitory effects on VSMC proliferation by increasing p-AMPK-Thr(172) and decreasing p-mTOR-Ser(2448) and p-p70S6K-Thr(389) in a PDGF-induced in vitro atherosclerosis model. Conclusion: These results demonstrated that telmisartan-activated AMPK inhibited basal and PDGF-stimulated VSMC proliferation, at least in part, by downregulating the mTOR/p70S6K signaling axis in a PPAR gamma-independent manner. These observations suggest that telmisartan could be used to treat arterial narrowing diseases such as atherosclerosis and restenosis.
DOI
10.3346/jkms.2020.35.e289
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연구기관 > 의과학연구소 > Journal papers
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