Protein kinase B/AKT mediates insulin‐like growth factor 1‐induced phosphorylation and nuclear export of histone deacetylase 5 via NADPH oxidase 4 activation in vascular smooth muscle cells

2019 ◽  
Vol 234 (10) ◽  
pp. 17337-17350 ◽  
Author(s):  
Paulina Pietruczuk ◽  
Ashish Jain ◽  
Estelle R. Simo‐Cheyou ◽  
Madhu B. Anand‐Srivastava ◽  
Ashok K. Srivastava
2002 ◽  
Vol 3 (2) ◽  
pp. 131-144 ◽  
Author(s):  
Hitomi Yamada ◽  
Toshio Tsushima ◽  
Hitomi Murakami ◽  
Yasuko Uchigata ◽  
Yasuhiko Iwamoto

Hyperinsulinemia has been shown to be associated with diabetic angiopathy. Migration and proliferation of vascular smooth muscle cells (VSMC) are the processes required for the development of atherosclerosis. In this study, we attempted to determine whether insulin affects mitogenic signaling induced by plateletderived growth factor (PDGF) in a rat VSMC cell line (A10 cells). PDGF stimulated DNA synthesis which was totally dependent on Ras, because transfection of dominant negative Ras resulted in complete loss of PDGF-stimulated DNA synthesis. Initiation of DNA synthesis was preceded by activation of Raf-1, MEK and MAP kinases (Erk 1 and Erk2). Treatment of the cells with PD98059, an inhibitor of MAPK kinase (MEK) attenuated but did not abolish PDGF-stimulated DNA synthesis, suggesting that MAPK is required but not essential for DNA synthesis. PDGF also stimulated phosphorylation of protein kinase B (Akt/PKB) and p70 S6Kinase (p70S6K) in a wortmannin-sensitive manner. Rapamycin, an inhibitor of p70S6K, markedly suppressed DNA synthesis. Low concentrations of insulin (1-10 nmol/l) alone showed little mitogenic activity and no significant effect on MAPK activity. However, the presence of insulin enhanced both DNA synthesis and MAPK activation by PDGF. The enhancing effect of insulin was not seen in cells treated with PD98059. Insulin was without effect on PDGF-stimulated activations of protein kinase B (Akt/PKB) and p70S6K. We conclude that insulin, at pathophysiologically relevant concentrations, potentiates the PDGFstimulated DNA synthesis, at least in part, by potentiating activation of the MAPK cascade. These results are consistent with the notion that hyperinsulinemia is a risk factor for the development of atherosclerosis.


1999 ◽  
Vol 276 (6) ◽  
pp. H1927-H1934 ◽  
Author(s):  
Tomosaburo Takahashi ◽  
Takahiro Taniguchi ◽  
Hiroaki Konishi ◽  
Ushio Kikkawa ◽  
Yuichi Ishikawa ◽  
...  

Involvement of Akt/Protein kinase B (PKB), a serine/threonine kinase with a pleckstrin-homology domain, in angiotensin II (ANG II)-induced signal transduction was investigated in cultured vascular smooth muscle cells (VSMC). Stimulation of the cells with ANG II led to a marked increase in the kinase activity of Akt/PKB, which coincided with Ser-473 phosphorylation. ANG II-stimulated Akt/PKB activation was rapid, concentration dependent, and inhibited by the AT1-receptor antagonist CV-11974, but not by pertussis toxin. Akt/PKB activity was stimulated by the Ca2+ ionophore ionomycin, suggesting the possible involvement of Ca2+ in ANG II-stimulated Akt/PKB activation. However, blockade of Ca2+ mobilization by BAPTA-AM only partially inhibited ANG II-stimulated Akt/PKB activation. ANG II-stimulated Akt/PKB activation was inhibited by the tyrosine kinase inhibitors genistein and herbimycin A and by the phosphatidylinositol 3-kinase (PI3K) inhibitors wortmannin and LY-294002. These results indicate that ANG II stimulates Akt/PKB activity via AT1 receptors in VSMC and that the activities of tyrosine kinase and PI3K are required for this activation.


2010 ◽  
Vol 299 (6) ◽  
pp. H1959-H1967 ◽  
Author(s):  
Yuan Li ◽  
Louis-Olivier Lévesque ◽  
Madhu B. Anand-Srivastava

We showed previously that vascular smooth muscle cells (VMSC) from spontaneously hypertensive rats (SHR) exhibit increased proliferation. The present study was undertaken to examine whether the enhanced levels of endogenous angiotensin (ANG) II and endothelin (ET)-1 contribute to the enhanced proliferation of VSMC from SHR and to further investigate the underlying mechanisms responsible for this response. The enhanced proliferation of VSMC from SHR compared with Wistar-Kyoto (WKY) rats was attenuated by losartan, BQ-123, BQ-788, and AG-1478, inhibitors of AT1, ETA, ETB and epidermal growth factor (EGF-R) receptors, respectively. In addition, BQ-123 and BQ-788 also attenuated the enhanced production of superoxide anion (O2−) and NADPH oxidase activity. Furthermore, diphenyleneiodonium (DPI, inhibitor of NADPH oxidase), N-acetyl-l-cysteine (NAC, O2− scavenger), and PP2 (inhibitor of c-Src) also inhibited the augmented proliferation of VSMC from SHR to WKY levels. In addition, the enhanced phosphorylation of EGF-R in VSMC from SHR compared with WKY was also attenuated by inhibitors of AT1, ETA, ETB, and EGF-R but not by inhibitors of platelet-derived growth factor receptor or insulin-like growth factor receptor. Furthermore, the enhanced phosphorylation of ERK1/2 in VSMC from SHR was also attenuated by AT1, ETA, ETB, c-Src, and EGF-R inhibitors. The phosphorylation of c-Src was significantly augmented in VSMC from SHR compared with VSMC from WKY and was attenuated by DPI and NAC. These data suggest that endogenous vasoactive peptides, through increased oxidative stress and resultant activation of c-Src, transactivate EGF-R, which through mitogen-activated protein (MAP) kinase signaling may contribute to the hyperproliferation of VSMC from SHR.


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