Abstract 18390: Ang II activates the RhoA Exchange Factor Arhgef1 in Humans

Circulation ◽  
2014 ◽  
Vol 130 (suppl_2) ◽  
Author(s):  
Maria-Luigia Carbone ◽  
Jérémy Brégeon ◽  
Nabila Devos ◽  
Anne Blanchard ◽  
Michel Azizi ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Rho Kinase ◽  
Renin Angiotensin System ◽  
Muscle Cells ◽  
Ang Ii ◽  
Kinase Signaling ◽  
Angiotensin System ◽  
Normotensive Subjects

Introduction: Although a causative role for RhoA-Rho kinase signaling has been recognized in the development of human hypertension, the molecular mechanism(s) as well as the RhoA exchange factors (GEFs) responsible for the over activation of RhoA remain unknown. Arhgef1 has been recently identified as a RhoA GEF involved in Ang II-mediated regulation of vascular tone and hypertension in mice. Hypothesis: Here we assessed the hypothesis that Arhgef1 is activated and involved in the activation of RhoA-Rho kinase signaling by Ang II in humans. Methods: We used in vitro stimulation of human coronary artery smooth muscle cells and human peripheral blood cells (PBMC) by Ang II (0.1 μmol/L), and PBMC isolated from normotensive subjects before and after activation of the renin-angiotensin system by a low-salt diet for 7 days (checked by the increase in plasma aldosterone and active renine). Activation of Arhgef1 was monitored by measuring its tyrosine phosphorylation by western blot and phosphorylation of the Rho kinase target MYPT was used to measure the activity of RhoA/Rho kinase signaling. Results: In vitro, Ang II induced activation of Arhgef1 in human vascular smooth muscle cells and PBMC. Silencing of Arhgef1 expression by siRNA in human vascular smooth muscle cells inhibited Ang II-induced activation of RhoA-Rho kinase signaling (0.67±0.12 vs 3.21±0.91relative to unstimulated condition, n=4, P<0.05). In normotensive subjects, activation of the renin-angiotensin system by a low-salt diet stimulated Arhgef1 activity in PBMC (1.26±0.12-fold over basal level, n=39, P<0.05). This activation was associated with an increase activity of RhoA-Rho kinase signaling (1.33±0.14-fold over basal level, n=39, P<0.05). Conclusions: Our results show that Ang II stimulates Arhgef1 activity and strongly suggest that Arhgef1 mediates Ang II-induced RhoA activation in humans. Moreover, we show for the first time that measurement of RhoA GEF activity in PBMC might be a useful method to evaluate RhoA GEF activity in humans.

scholarly journals MicroRNA-141 Inhibits the Proliferation of Penile Cavernous Smooth Muscle Cells Associated with Down-Regulation of the Rhoa/Rho Kinase Signaling Pathway

2018 ◽  
Vol 48 (1) ◽  
pp. 348-360 ◽  
Author(s):  
Ying Zhang ◽  
Linpei Jia ◽  
Wei Ji ◽  
Hai Li
Keyword(s):  
Smooth Muscle ◽  
Erectile Dysfunction ◽  
Smooth Muscle Cells ◽  
Signaling Pathway ◽  
Rho Kinase ◽  
Muscle Cells ◽  
Kinase Signaling ◽  
Kinase Signaling Pathway ◽  
Cavernous Smooth Muscle

Background/Aims: The role of the RhoA/Rho kinase signaling pathway in diabetes mellitus-induced erectile dysfunction has been partially understood. Methods: In the present study, we explored the changes of the RhoA/Rho associated kinase (ROCK) signaling pathway in diabetic erectile dysfunction in vivo and the effects of microRNA-141 on the RhoA/ROCK signaling pathway in vitro. Results: The mRNA and protein expressions of RhoA and ROCK2 were significantly increased while the expression of microRNA-141 was decreased in the penile cavernous smooth muscle cells of rats with diabetic erectile dysfunction. Moreover, increased expression of microRNA-141, decreased expressions of RhoA and ROCK2 (mRNA and protein), accelerated cell proliferation rate and reduced cell apoptosis were found in the microRNA-141 mimics group and the siRNA-Rho group. The microRNA-141 expression in the microRNA-141 inhibitors + siRNA-Rho group was significantly decreased. microRNA-141 specifically bound to Rho-3’-UTR and down-regulated the expression of Rho gene at the post transcriptional level. Conclusion: Decreased expression of miR-141 is associated with up-regulation of RhoA and ROCK2 in the RhoA/ROCK signaling pathway in rats with diabetic erectile dysfunction. miR-141 inhibits the growth of penile cavernous smooth muscle cells associated with down-regulation of the RhoA/ROCK signaling pathway in vitro.

Angiotensin II modulates frizzled-2 receptor expression in rat vascular smooth muscle cells

2005 ◽  
Vol 108 (6) ◽  
pp. 523-530 ◽  
Author(s):  
Giovanna CASTOLDI ◽  
Serena REDAELLI ◽  
Willy M. M. van de GREEF ◽  
Cira R. T. di GIOIA ◽  
Giuseppe BUSCA ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Angiotensin Ii ◽  
Vascular Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Vascular Smooth Muscle Cells ◽  
Muscle Cells ◽  
Ang Ii ◽  
Aortic Smooth Muscle

Ang II (angiotensin II) has multiple effects on vascular smooth muscle cells through the modulation of different classes of genes. Using the mRNA differential-display method to investigate gene expression in rat aortic smooth muscle cells in culture in response to 3 h of Ang II stimulation, we observed that Ang II down-regulated the expression of a member of the family of transmembrane receptors for Wnt proteins that was identified as Fzd2 [Fzd (frizzled)-2 receptor]. Fzds are a class of highly conserved genes playing a fundamental role in the developmental processes. In vitro, time course experiments demonstrated that Ang II induced a significant increase (P<0.05) in Fzd2 expression after 30 min, whereas it caused a significant decrease (P<0.05) in Fzd2 expression at 3 h. A similar rapid up-regulation after Ang II stimulation for 30 min was evident for TGFβ1 (transforming growth factor β1; P<0.05). To investigate whether Ang II also modulated Fzd2 expression in vivo, exogenous Ang II was administered to Sprague–Dawley rats (200 ng·kg−1 of body weight·min−1; subcutaneously) for 1 and 4 weeks. Control rats received normal saline. After treatment, systolic blood pressure was significantly higher (P<0.01), whereas plasma renin activity was suppressed (P<0.01) in Ang II- compared with the saline-treated rats. Ang II administration for 1 week did not modify Fzd2 expression in aorta of Ang II-treated rats, whereas Ang II administration for 4 weeks increased Fzd2 mRNA expression (P<0.05) in the tunica media of the aorta, resulting in a positive immunostaining for fibronectin at this time point. In conclusion, our data demonstrate that Ang II modulates Fzd2 expression in aortic smooth muscle cells both in vitro and in vivo.

Abstract 268: Angiotensin II Up-regulates Serum and Glucocorticoid Inducible Kinase 1 in Remodeled Blood Vessels

Hypertension ◽  
2012 ◽  
Vol 60 (suppl_1) ◽  
Author(s):  
Tarianna Stewart-Hutto ◽  
Sharon Francis
Keyword(s):  
Blood Pressure ◽  
Smooth Muscle ◽  
Angiotensin Ii ◽  
Protein Expression ◽  
Smooth Muscle Cells ◽  
Blood Vessels ◽  
Muscle Cells ◽  
Ang Ii ◽  
Induced Hypertension

Angiotensin II (Ang II) is a potent vasoconstrictor that activates vascular smooth muscle and in excess amounts is an important contributing factor in the development of hypertension. However, the downstream signaling pathways mediating the effects of Ang II in the vasculature is not fully known. The present study examines the regulation of serum- and glucocorticoid inducible kinase (SGK1) a serine/threonine kinase that has been implicated in hyperglycemia- and salt-induced hypertension. We hypothesized that SGK1 is up-regulated in pathologically remodeled blood vessels in the context of Ang II-induced hypertension and by Ang II in vascular smooth muscle cells in vitro . Therefore, we examined SGK1 protein expression in human aortic smooth muscle cells (HASM) stimulated with increasing doses of Ang II (0-100nM) in vitro. Our results demonstrated a dose-dependent increase in SGK1 protein expression. SGK1 expression was increased approximately 10-fold following 60 minutes of stimulation with 100nM Ang II. Next, we examined SGK1 expression in the vasculature in vivo in a mouse model of Ang II-induced hypertension. Based on immunohistochemistry, our data indicated that SGK1 was up-regulated in the medial layer of the aorta in mice infused with 0.7mg/kg/day Ang II, a dose that significantly increases blood pressure. Overall, these results indicate that Ang II up-regulates SGK1 in both smooth muscle cells and blood vessels. Our results also suggest that SGK1 may be responsible for the increase in blood pressure and remodeling of the blood vessels.

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