Chronic Angiotensin II Augments Integrin-Dependent Cell Functions Via PKC and Map-Kinase Activation in Rat Vsmcs

Hypertension ◽  
2000 ◽  
Vol 36 (suppl_1) ◽  
pp. 707-707
Author(s):  
Kai Kappert ◽  
Florian Blaschke ◽  
Gunther Schmidt ◽  
Eckart Fleck ◽  
Ronald E Law ◽  
...  
Keyword(s):  
Angiotensin Ii ◽  
Protein Kinase ◽  
Map Kinase ◽  
Critical Role ◽  
Collagen I ◽  
Mitogen Activated Protein Kinase ◽  
Chronic Hypertension ◽  
Ang Ii ◽  
Kinase Activation ◽  
Cell Functions

P78 The activation of local and systemic renin-angiotensin-system is directly and indirectly involved in the mechanisms of vascular remodeling during chronic hypertension. The following study investigated the effect of chronic angiotensin II (AII) admininstration on cell- matrix interaction of VSMCs in vitro. Adhesion to vitronectin (VN) and collagen I (ColI) as well as migration of rat vascular smooth muscle cells (VSMCs) were significantly augmented by chronic treatment with AII for 48 hours and 72 hours. These changes were not due to an increase of the integrins on the cells surface known to be capable in binding vitronectin and collagen I: alpha1, alpha5, beta1 and beta5, as demonstrated by flow cytometry. Also the phosporylation of the focal adhesion kinase (FAK), known to play an important role in adhesion and spreading processes, was not affected after chronic stimulation with Ang II. Downregulation of PKC activity by phorbol-myristate acetate (PMA, 0.1μmol/L), or treatment with the PKC inhibitor calphostin C before treatment with AII significantly reduced the effect of AII on adhesion to VN and ColI (each p<0.05) and also inhibited the effect on VSMC migration (p<0.01). Inhibition of MAP-kinase activation with PD 98059 before treatment with AII demonstrated comparable effects. PD 98059 significantly reduced the increase in adhesion on both, VN and ColI and diminished the effect on PDGF-directed migration of rVSMCs. Theses data indicate that regulation of these functional alterations in integrin-dependent cellular behaviour after chronic AII treatment involved protein kinase C (PKC) and mitogen-activated protein kinase (MAPK)-activation. These data demonstrate that Ang II plays a critical role in augmenting cellular functions in VSMCs, which are important molecular events for the development of vascular hyperplasia .

scholarly journals Sodium Tanshinone IIA Sulfonate Prevents Angiotensin II-Induced Differentiation of Human Atrial Fibroblasts into Myofibroblasts

2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Tangting Chen ◽  
Miaoling Li ◽  
Xuehui Fan ◽  
Jun Cheng ◽  
Liqun Wang
Keyword(s):  
Angiotensin Ii ◽  
Critical Role ◽  
Water Soluble ◽  
Collagen I ◽  
Tanshinone Iia ◽  
Ang Ii ◽  
Induced Differentiation ◽  
Fibroblast Migration ◽  
Collagen Iii ◽  
Sodium Tanshinone Iia Sulfonate

Differentiation of atrial fibroblasts into myofibroblasts plays a critical role in atrial fibrosis. Sodium tanshinone IIA sulfonate (DS-201), a water-soluble derivative of tanshinone IIA, has been shown to have potent antifibrotic properties. However, the protective effects of DS-201 on angiotensin II- (Ang II-) induced differentiation of atrial fibroblasts into myofibroblasts remain to be elucidated. In this study, human atrial fibroblasts were stimulated with Ang II in the presence or absence of DS-201. Then, α-smooth muscle actin (α-SMA), collagen I, and collagen III expression and reactive oxygen species (ROS) generation were measured. The expression of transforming growth factor-β1 (TGF-β1) and the downstream signaling of TGF-β1, such as phosphorylation of Smad2/3, were also determined. The results demonstrated that DS-201 significantly prevented Ang II-induced human atrial fibroblast migration and decreased Ang II-induced α-SMA, collagen I, and collagen III expression. Furthermore, increased production of ROS and expression of TGF-β1 stimulated by Ang II were also significantly inhibited by DS-201. Consistent with these results, DS-201 significantly inhibited Ang II-evoked Smad2/3 phosphorylation and periostin expression. These results and the experiments involving N-acetyl cysteine (antioxidant) and an anti-TGF-β1 antibody suggest that DS-201 prevent Ang II-induced differentiation of atrial fibroblasts to myofibroblasts, at least in part, through suppressing oxidative stress and inhibiting the activation of TGF-β1 signaling pathway. All of these data indicate the potential utility of DS-201 for the treatment of cardiac fibrosis.

Angiotensin II type 1 receptor-mediated activation of Ras in cultured rat vascular smooth muscle cells

1996 ◽  
Vol 271 (2) ◽  
pp. H595-H601 ◽  
Author(s):  
M. Okuda ◽  
Y. Kawahara ◽  
M. Yokoyama
Keyword(s):  
Smooth Muscle ◽  
Angiotensin Ii ◽  
Smooth Muscle Cells ◽  
Map Kinase ◽  
Vascular Smooth Muscle Cells ◽  
Ang Ii ◽  
Kinase Activation ◽  
Ras Activation ◽  
Fos Expression

Angiotensin II (ANG II), a potent growth-promoting factor of vascular smooth muscle cells (VSMC), induces activation of mitogen-activated protein (MAP) kinases and subsequent expression of the c-fos protooncogene in VSMC. However, it remains obscure whether ANG II induces activation of the ras protooncogene product (Ras), and if it does, whether Ras is involved in signaling from the ANG II receptor to the MAP kinase pathway in VSMC. In cultured VSMC, ANG II activated Ras comparably to epidermal growth factor. ANG II-induced Ras activation was detectable within 1 min and maximal at 2–5 min. The ANG II type 1 (AT1) receptor antagonist, CV-11974, completely inhibited this reaction. Pertussis toxin treatment of VSMC inhibited ANG II-induced Ras activation by approximately 70% but had no effect on ANG II-induced MAP kinase activation and c-fos expression. These results indicate that ANG II activates Ras via AT1 receptors, which are predominantly linked to a G protein of the Gi subfamily in VSMC1 and suggest that Ras activation may not be a prerequisite for ANG II-induced MAP kinase activation and c-fos expression in this cell type.

scholarly journals Identification of a Novel Mitogen-Activated Protein Kinase Kinase Activation Domain Recognized by the Inhibitor PD 184352

2002 ◽  
Vol 22 (21) ◽  
pp. 7593-7602 ◽  
Author(s):  
Amy M. Delaney ◽  
John A. Printen ◽  
Huifen Chen ◽  
Eric B. Fauman ◽  
David T. Dudley
Keyword(s):  
Protein Kinase ◽  
Map Kinase ◽  
Genetic Screen ◽  
Mitogen Activated Protein Kinase ◽  
Erk Signaling ◽  
Signaling Cascade ◽  
Kinase Activation ◽  
Basal Activity ◽  
Mitogen Activated Protein

ABSTRACT Utilizing a genetic screen in the yeast Saccharomyces cerevisiae, we identified a novel autoactivation region in mammalian MEK1 that is involved in binding the specific MEK inhibitor, PD 184352. The genetic screen is possible due to the homology between components of the yeast pheromone response pathway and the eukaryotic Raf-MEK-ERK signaling cascade. Using the FUS1::HIS3 reporter as a functional readout for activation of a reconstituted Raf-MEK-ERK signaling cascade, randomly mutagenized MEK variants that were insensitive to PD 184352 were obtained. Seven single-base-change mutations were identified, five of which mapped to kinase subdomains III and IV of MEK. Of the seven variants, only one, a leucine-to-proline substitution at amino acid 115 (Leu115Pro), was completely insensitive to PD 184352 in vitro (50% inhibitory concentration >10 μM). However, all seven mutants displayed strikingly high basal activity compared to wild-type MEK. Overexpression of the MEK variants in HEK293T cells resulted in an increase in mitogen-activated protein (MAP) kinase phosphorylation, a finding consistent with the elevated basal activity of these constructs. Further, treatment with PD 184352 failed to inhibit Leu115Pro-stimulated MAP kinase activation in HEK293T cells, whereas all other variants had some reduction in phospho-MAP kinase levels. By using cyclic AMP-dependent protein kinase (1CDK) as a template, an MEK homology model was generated, with five of the seven identified residues clustered together, forming a potential hydrophobic binding pocket for PD 184352. Additionally, the model allowed identification of other potential residues that would interact with the inhibitor. Directed mutation of these residues supported this region's involvement with inhibitor binding.

scholarly journals Sprouty-4 negatively regulates cell spreading by inhibiting the kinase activity of testicular protein kinase

2005 ◽  
Vol 387 (3) ◽  
pp. 627-637 ◽  
Author(s):  
Yoshikazu TSUMURA ◽  
Jiro TOSHIMA ◽  
Onno C. LEEKSMA ◽  
Kazumasa OHASHI ◽  
Kensaku MIZUNO
Keyword(s):  
Protein Kinase ◽  
Map Kinase ◽  
Inhibitory Activity ◽  
Kinase Activity ◽  
Cultured Cells ◽  
Critical Role ◽  
Cell Spreading ◽  
Inhibitory Effect ◽  
Mitogen Activated Protein Kinase ◽  
Mitogen Activated Protein

TESK1 (testicular protein kinase 1) is a serine/threonine kinase that phosphorylates cofilin and plays a critical role in integrin-mediated actin cytoskeletal reorganization and cell spreading. We previously showed that TESK1 interacts with Sprouty-4 (referred to as Spry4), an inhibitor of growth factor-induced Ras/MAP (mitogen-activated protein) kinase signalling, but the functional role of this interaction has remained unknown. In the present study, we show that Spry4 inhibits the kinase activity of TESK1 by binding to it through the C-terminal cysteine-rich region. Expression of Spry4 in cultured cells suppressed integrin-mediated cell spreading, and TESK1 reversed the inhibitory effect of Spry4 on cell spreading. Furthermore, Spry4 suppressed integrin- and TESK1-mediated cofilin phosphorylation during the spreading of cells on laminin. These findings suggest that Spry4 suppresses cell spreading by inhibiting the kinase activity of TESK1. Although tyrosine phosphorylation is required for the inhibitory activity of Spry4 on a Ras/MAP kinase pathway, mutation of the corresponding tyrosine residue (Tyr-75 in human Spry4) to an alanine had no apparent effect on its inhibitory actions on TESK1 activity and cell spreading, which suggests a novel cellular function of Spry to regulate the actin cytoskeleton, independent of its inhibitory activity on the Ras/MAP kinase signalling.

scholarly journals Angiotensin II Activates Mitogen-Activated Protein Kinase Via Protein Kinase C and Ras/Raf-1 Kinase in Bovine Adrenal Glomerulosa Cells

Endocrinology ◽  
1998 ◽  
Vol 139 (4) ◽  
pp. 1801-1809 ◽  
Author(s):  
Ying Tian ◽  
Roger D. Smith ◽  
Tamas Balla ◽  
Kevin J. Catt
Keyword(s):  
Protein Kinase C ◽  
Angiotensin Ii ◽  
Protein Kinase ◽  
Time Course ◽  
Mitogen Activated Protein Kinase ◽  
Ang Ii ◽  
Mapk Activation ◽  
Kinase C ◽  
Mitogen Activated Protein ◽  
Glomerulosa Cells

Abstract Angiotensin II (Ang II) stimulates growth and mitogenesis in bovine adrenal glomerulosa cells, but little is known about the signaling pathways that mediate these responses. An analysis of the growth-promoting pathways in cultured bovine adrenal glomerulosa cells revealed that Ang II, acting via the AT1 receptor, caused rapid but transient activation of mitogen-activated protein kinase (MAPK), with an ED50 of 10–50 pm. Although neither Ca2+ influx nor Ca2+ release from intracellular stores was sufficient to activate MAPK, Ca2+ appeared to play a permissive role in this response. A major component of Ang II-induced MAPK activation was insensitive to pertussis toxin (PTX), although a minor PTX-sensitive component could not be excluded. Ang II also induced the rapid activation of ras and raf-1 kinase with time-courses that correlated with that of MAPK. Activation of protein kinase C (PKC) by phorbol 12-myristate 13-acetate was sufficient to activate both MAPK and raf-1 kinase. However, whereas PKC depletion had no effect on Ang II-induced raf-1 kinase activation, it attenuated Ang II-induced MAPK activation. Ang II also stimulated a mobility shift of raf-1, reflecting hyperphosphorylation of the kinase. However, unlike its activation, raf-1 hyperphosphorylation was dependent on PKC and its time-course correlated not with activation, but rather with deactivation of the kinase. Taken together, these findings indicate that Ang II stimulates multiple pathways to MAPK activation via PKC and ras/raf-1 kinase in bovine adrenal glomerulosa cells.

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