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 Role of MicroRNA-145 in DNA Damage Signalling and Senescence in Vascular Smooth Muscle Cells of Type 2 Diabetic Patients

Cells ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 919
Author(s):  
Karen E. Hemmings ◽  
Kirsten Riches-Suman ◽  
Marc A. Bailey ◽  
David J. O’Regan ◽  
Neil A. Turner ◽  
...  
Keyword(s):  
Dna Damage ◽  
Smooth Muscle ◽  
Vascular Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Vascular Smooth Muscle Cells ◽  
Muscle Cells ◽  
Expression Levels ◽  
Elevated Expression ◽  
Dna Damage Signalling

Increased cardiovascular morbidity and mortality in individuals with type 2 diabetes (T2DM) is a significant clinical problem. Despite advancements in achieving good glycaemic control, this patient population remains susceptible to macrovascular complications. We previously discovered that vascular smooth muscle cells (SMC) cultured from T2DM patients exhibit persistent phenotypic aberrancies distinct from those of individuals without a diagnosis of T2DM. Notably, persistently elevated expression levels of microRNA-145 co-exist with characteristics consistent with aging, DNA damage and senescence. We hypothesised that increased expression of microRNA-145 plays a functional role in DNA damage signalling and subsequent cellular senescence specifically in SMC cultured from the vasculature of T2DM patients. In this study, markers of DNA damage and senescence were unambiguously and permanently elevated in native T2DM versus non-diabetic (ND)-SMC. Exposure of ND cells to the DNA-damaging agent etoposide inflicted a senescent phenotype, increased expression of apical kinases of the DNA damage pathway and elevated expression levels of microRNA-145. Overexpression of microRNA-145 in ND-SMC revealed evidence of functional links between them; notably increased secretion of senescence-associated cytokines and chronic activation of stress-activated intracellular signalling pathways, particularly the mitogen-activated protein kinase, p38α. Exposure to conditioned media from microRNA-145 overexpressing cells resulted in chronic p38α signalling in naïve cells, evidencing a paracrine induction and reinforcement of cell senescence. We conclude that targeting of microRNA-145 may provide a route to novel interventions to eliminate DNA-damaged and senescent cells in the vasculature and to this end further detailed studies are warranted.

scholarly journals Role of microRNA-145 in DNA damage signalling and senescence in vascular smooth muscle cells of Type 2 diabetic patients

2020 ◽  
Author(s):  
Karen E Hemmings ◽  
Kirsten Riches-Suman ◽  
Marc A Bailey ◽  
David J O’Regan ◽  
Neil A Turner ◽  
...  
Keyword(s):  
Dna Damage ◽  
Smooth Muscle ◽  
Vascular Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Vascular Smooth Muscle Cells ◽  
Muscle Cells ◽  
Expression Levels ◽  
Elevated Expression ◽  
Dna Damage Signalling

AbstractIncreased cardiovascular morbidity and mortality in individuals with type 2 diabetes (T2DM) is a significant clinical problem. Despite advancements in achieving good glycaemic control, this patient population remains susceptible to macrovascular complications. We previously discovered that vascular smooth muscle cells (SMC) cultured from T2DM patients exhibit persistent phenotypic aberrancies distinct from those of individuals without a diagnosis of T2DM. Notably, persistently elevated expression levels of microRNA-145 co-exist with characteristics consistent with aging, DNA damage and senescence. We hypothesised that increased expression of microRNA-145 plays a functional role in DNA damage signalling and subsequent cellular senescence specifically in SMC cultured from the vasculature of T2DM patients. In this study, markers of DNA damage and senescence were unambiguously and permanently elevated in native T2DM versus non-diabetic (ND)-SMC. Exposure of ND cells to the DNA-damaging agent etoposide inflicted a senescent phenotype, increased expression of apical kinases of the DNA damage pathway and elevated expression levels of microRNA-145. Overexpression of microRNA-145 in ND-SMC revealed evidence of functional links between them; notably increased secretion of senescence-associated cytokines and chronic activation of stress-activated intracellular signalling pathways, particularly the mitogen-activated protein kinase, p38α. Exposure to conditioned media from microRNA-145 overexpressing cells resulted in chronic p38α signalling in naïve cells, evidencing a paracrine induction and reinforcement of cell senescence. We conclude that targeting of microRNA-145 may provide a route to novel interventions to eliminate DNA-damaged and senescent cells in the vasculature and to this end further detailed studies are warranted.

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.

Ets-1 is an early response gene activated by ET-1 and PDGF-BB in vascular smooth muscle cells

1998 ◽  
Vol 274 (2) ◽  
pp. C472-C480 ◽  
Author(s):  
Shinji Naito ◽  
Shunichi Shimizu ◽  
Shigeto Maeda ◽  
Jianwei Wang ◽  
Richard Paul ◽  
...  
Keyword(s):  
Gene Expression ◽  
Smooth Muscle ◽  
Vascular Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Vascular Smooth Muscle Cells ◽  
Inositol Phosphate ◽  
Muscle Cells ◽  
Tetraacetic Acid ◽  
Acetoxymethyl Ester ◽  
Intracellular Ca

Ets-1 is a transcription factor that activates expression of matrix-degrading proteinases such as collagenase and stromelysin. To study the control of ets-1 gene expression in rat vascular smooth muscle cells (VSMC), cells were exposed to factors known to regulate VSMC migration and proliferation. Platelet-derived growth factor-BB (PDGF-BB), endothelin-1 (ET-1), and phorbol 12-myristate 13-acetate (PMA) induced a dose-dependent expression of ets-1 mRNA. These effects were abrogated by inhibition of protein kinase C (PKC) by H-7 or chronic PMA treatment. Ets-1 mRNA was superinduced by PDGF-BB and ET-1 in the presence of cycloheximide. The chelation of intracellular Ca2+ by 1,2-bis(2-aminophenoxy)ethane- N, N, N′, N′-tetraacetic acid-acetoxymethyl ester and the depletion of endoplasmic reticulum intracellular Ca2+concentration ([Ca2+]i) by thapsigargin inhibited PDGF-BB- and ET-1-induced ets-1 mRNA, whereas ethylene glycol-bis(β-aminoethyl ether)- N, N, N′, N′-tetraacetic acid had no effect. However, [Ca2+]irelease alone was not sufficient to increase ets-1 mRNA. Forskolin blocked ET-1-, PDGF-BB-, and PMA-induced ets-1 mRNA, as well as inositol phosphate formation, consistent with an effect through impairment of PKC activation. Inhibitors of ets-1 gene expression, such as H-7 and herbimycin A, inhibited the ET-1 induction of collagenase I mRNA. We propose that ets-1 may be an important element in the orchestration of matrix proteinase expression and of vascular remodeling after arterial injury.

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
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