scholarly journals Impaired insulin-stimulated myosin phosphatase Rho-interacting protein signaling in diabetic Goto-Kakizaki vascular smooth muscle cells

2012 ◽  
Vol 302 (9) ◽  
pp. C1371-C1381 ◽  
Author(s):  
Jin Hee Lee ◽  
Thomas Palaia ◽  
Louis Ragolia
Keyword(s):  
Type 2 Diabetes ◽  
Smooth Muscle ◽  
Vascular Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Vascular Smooth Muscle Cells ◽  
Muscle Cells ◽  
Myosin Phosphatase ◽  
Interacting Protein ◽  
Impaired Insulin

Insulin resistance associated with Type 2 diabetes contributes to impaired vasorelaxation and therefore contributes to the enhanced incidence of hypertension observed in diabetes. In this study, we examined the role of insulin on the association of the myosin-binding subunit of myosin phosphatase (MYPT1) to myosin phosphatase Rho-interacting protein (MRIP), a relatively novel member of the myosin phosphatase complex that directly binds RhoA in vascular smooth muscle cells (VSMCs). Through a series of molecular and cellular studies, we investigated whether insulin stimulates the binding of MRIP to MYPT1 and compared the results generated from VSMCs isolated from both Wistar-Kyoto (WKY) control and Goto-Kakizaki (GK) diabetic rats. We demonstrate for the first time that insulin stimulates the binding of MRIP to MYPT1 in a dose- and time-dependent manner, as determined by immunoprecipitation, implying a regulatory role for MRIP in insulin-induced vasodilation signaling via MYPT1 interaction. VSMCs from GK model of Type 2 diabetes had impaired insulin-induced MRIP/MYPT1 binding as well as reduced MRIP expression. Adenovirus-mediated overexpression of MRIP in GK VSMCs led to significantly improved insulin-stimulated MRIP/MYPT1 binding. Finally, insulin-stimulated MRIP translocation out of stress fibers, which was observed in control VSMCs, was impaired in GK VSMCs. We believe the impaired expression of MRIP, and therefore decreased insulin-stimulated MRIP/MYPT1 association, in the GK diabetic model may contribute to the impaired insulin-mediated vasodilation observed in the diabetic vasculature and provides a novel therapeutic strategy for the treatment of Type 2 diabetes.

Calcium homeostasis in vascular smooth muscle cells is altered in type 2 diabetes by Bcl-2 protein modulation of InsP3R calcium release channels

2012 ◽  
Vol 302 (1) ◽  
pp. H124-H134 ◽  
Author(s):  
Gopal V. Velmurugan ◽  
Carl White
Keyword(s):  
Type 2 Diabetes ◽  
Smooth Muscle ◽  
Vascular Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Vascular Smooth Muscle Cells ◽  
Single Cells ◽  
Muscle Cells ◽  
Expression Levels ◽  
Intracellular Ca

This study examines the extent to which the antiapoptotic Bcl-2 proteins Bcl-2 and Bcl-xLcontribute to diabetic Ca2+dysregulation and vessel contractility in vascular smooth muscle cells (VSMCs) through their interaction with inositol 1,4,5-trisphosphate receptor (InsP3R) intracellular Ca2+release channels. Measurements of intracellular ([Ca2+]i) and sarcoplasmic reticulum ([Ca2+]SR) calcium concentrations were made in primary cells isolated from diabetic ( db/db) and nondiabetic ( db/m) mice. In addition, [Ca2+]iand constriction were recorded simultaneously in isolated intact arteries. Protein expression levels of Bcl-xLbut not Bcl-2 were elevated in VSMCs isolated from db/db compared with db/m age-matched controls. In single cells, InsP3-evoked [Ca2+]isignaling was enhanced in VSMCs from db/db mice compared with db/m. This was attributed to alterations in the intrinsic properties of the InsP3R itself because there were no differences between db/db and db/m in the steady-state [Ca2+]SRor InsP3R expression levels. Moreover, in permeabilized cells the rate of InsP3R-dependent SR Ca2+release was increased in db/db compared with db/m VSMCs. The enhanced InsP3-dependent SR Ca2+release was attenuated by the Bcl-2 protein inhibitor ABT-737 only in diabetic cells. Application of ABT-737 similarly attenuated enhanced agonist-induced [Ca2+]isignaling only in intact aortic and mesenteric db/db vessels. In contrast, ABT-737 had no effect on agonist-evoked contractility in either db/db or db/m vessels. Taken together, the data suggest that in type 2 diabetes the mechanism for [Ca2+]idysregulation in VSMCs involves Bcl-2 protein-dependent increases in InsP3R excitability and that dysregulated [Ca2+]isignaling does not appear to contribute to increased vessel reactivity.

scholarly journals Angiotensin II type 2 receptor activation induces RhoA inhibition through Phosphorylation of its Serine 188 in Vascular Smooth Muscle Cells

2006 ◽  
Vol 20 (4) ◽  
Author(s):  
Malvyne Rolli‐Derkinderen ◽  
Christophe Guilluy ◽  
Laurent Loufrani ◽  
Daniel Henrion ◽  
Gervaise Loirand ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Angiotensin Ii ◽  
Vascular Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Vascular Smooth Muscle Cells ◽  
Muscle Cells ◽  
Receptor Activation

scholarly journals Angiotensin II Type 2 Receptors Stimulate Collagen Synthesis in Cultured Vascular Smooth Muscle Cells

Hypertension ◽  
2000 ◽  
Vol 36 (5) ◽  
pp. 845-850 ◽  
Author(s):  
Mizuo Mifune ◽  
Hiroyuki Sasamura ◽  
Ryoko Shimizu-Hirota ◽  
Hitoshi Miyazaki ◽  
Takao Saruta
Keyword(s):  
Smooth Muscle ◽  
Angiotensin Ii ◽  
Vascular Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Vascular Smooth Muscle Cells ◽  
Collagen Synthesis ◽  
Muscle Cells

scholarly journals 2-Methoxyestradiol blocks the RhoA/ROCK1 pathway in human aortic smooth muscle cells

2015 ◽  
Vol 309 (12) ◽  
pp. E995-E1007 ◽  
Author(s):  
Lisa Rigassi ◽  
Federica Barchiesi Bozzolo ◽  
Eliana Lucchinetti ◽  
Michael Zaugg ◽  
Jürgen Fingerle ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Vascular Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Vascular Smooth Muscle Cells ◽  
Light Chain ◽  
Myosin Light Chain ◽  
Molecular Mechanisms ◽  
Muscle Cells ◽  
Myosin Phosphatase ◽  
Downstream Signaling

2-Methoxyestradiol (2-ME), a metabolite of estradiol with little affinity for estrogen receptors, inhibits proliferation of vascular smooth muscle cells; however, the molecular mechanisms underlying this effect are incompletely understood. Our previous work shows that 2-ME inhibits initiation (blocks phosphorylation of ERK and Akt) and progression (reduces cyclin expression and increases expression of cyclin inhibitors) of the mitogenic pathway and interferes with mitosis (disrupts tubulin organization). Because the RhoA/ROCK1 pathway (RhoA → ROCK1 → myosin phosphatase targeting subunit → myosin light chain) is involved in cytokinesis, herein we tested the concept that 2-ME also blocks the RhoA/ROCK1 pathway. Because of the potential importance of 2-ME for preventing/treating vascular diseases, experiments were conducted in female human aortic vascular smooth muscle cells. Microarray transcriptional profiling suggested an effect of 2-ME on the RhoA/ROCK1 pathway. Indeed, 2-ME blocked mitogen-induced GTP-bound RhoABC expression and membrane-bound RhoA, suggesting interference with the activation of RhoA. 2-ME also reduced ROCK1 expression, suggesting reduced production of the primary downstream signaling kinase of the RhoA pathway. Moreover, 2-ME inhibited RhoA/ROCK1 pathway downstream signaling, including phosphorylated myosin phosphatase targeting subunit and myosin light chain; the ROCK1 inhibitor H-1152 mimicked these effects of 2-ME; both 2-ME and H-1152 blocked cytokinesis. 2-ME also reduced the expression of tissue factor, yet another downstream signaling component of the RhoA/ROCK1 pathway. We conclude that 2-ME inhibits the pathway RhoA → ROCK1 → myosin phosphatase targeting subunit → myosin light chain, and this likely contributes to the reduced cytokinesis in 2-ME treated HASMCs.

Sign in / Sign up

Export Citation Format

Share Document