Puerarin attenuates high-glucose-and diabetes-induced vascular smooth muscle cell proliferation by blocking PKCbeta2/Rac1-dependent signaling.
ABSTRACT Oxidative stress has been implicated in several steps leading to the development of diabetic vascular complications. The purpose of this study was to determine the efficacy and the possible mechanism of puerarin on high-glucose (HG; 25 mM)-induced proliferation of cultured rat vascular smooth muscle cells (VSMCs) and neointimal formation in a carotid arterial balloon injury model of obese Zucker rats. Our data demonstrated that puerarin significantly inhibited rat VSMC proliferation as well as reactive oxygen species (ROS) generation and NADPH oxidase activity induced by HG treatment. Further studies revealed that HG treatment resulted in phosphorylation and membrane translocation of PKCbeta2 as well as Rac1, p47phox, and p67phox subunits, leading to NADPH oxidase activation. Puerarin treatment remarkably disrupted the phosphorylation and membrane translocation of PKCbeta2 as well as Rac1, p47phox, and p67phox subunits. Blocking PKCbeta2 by infection with AdDNPKCbeta2 also abolished HG-induced phosphorylation and membrane translocation of Rac1, p47phox, and p67phox subunits as well as ROS production and NADPH oxidase activation in VSMCs. In vivo neointimal formation of obese Zucker rats evoked by balloon injury was evidently attenuated by the administration of puerarin. These results demonstrate that puerarin may exert inhibitory effects on HG-induced VSMC proliferation via interfering with PKCbeta2/Rac1-dependent ROS pathways, thus resulting in the attenuation of neointimal formation in the context of hyperglycemia in diabetes mellitus.
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ABSTRACT: Several studies demonstrate that estradiol can prevent arterial calcification. However, little is known regarding the effect of puerarin, a phytoestrogen extracted from Radix Puerariae, on arterial calcification. The aim of the present study was to determine whether puerarin reduced osteoblastic differentiation of calcifying vascular smooth muscle cells (CVSMCs). The CVSMCs were isolated from mice aorta and treated with different concentrations of puerarin. The alkaline phosphatase (ALP) activity, osteocalcin secretion and Runx2 expression were determined. To examine whether estrogen receptors (ERs) PI3K and Akt play a role in this effect, ICI182789, phosphoinositide 3-kinase (PI3K) inhibitor, LY294002, or the Akt inhibitor, 1L-6-hydroxymethyl-chiro-inositol 2-(R)-2-O-methyl-3-O-octadecylcarbonate (HIMO) was used. Our results showed puerarin could inhibit ALP activity, osteocalcin secretion and Runx2 expression in CVSMCs. Puerarin could induce the activation of Akt. Furthermore, pretreatment of ICI182780, LY294002, HIMO could abolish the effect of puerarin on ALP activity in CVSMCs. Our experiment demonstrated that puerain could attenuate the osteoblastic differentiation of VSMCs through the ER/PI3K-Akt signal pathway.The American Journal of Chinese Medicine 01/2014; 42(2):337-47. · 2.28 Impact Factor
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ABSTRACT: Diabetes mellitus (DM) is a complex syndrome which leads to multiple dysfunctions including vascular disorders. Hyperglycemia is considered to be a key factor responsible for the development of diabetic vascular complications and can mediate their adverse effects through multiple pathways. One of those mechanisms is the activation of protein kinase C (PKC). This important regulatory enzyme is involved in a signal transduction of several vascular functions including vascular smooth muscle contractility. Many studies have shown that hyperglycemia in DM results in oxidative stress. Overproduction of reactive oxygen species (ROS) by different oxidases and the mitochondrial electron transport chain (ETC), advanced glycation end products, polyol pathway flux, and hyperglicemia-induced rising in diacylglycerol (DAG) contribute to the activation of PKC. Activation of endothelial PKC in DM leads to endothelium-dependent vasodilator dysfunction. The main manifestations of this are inhibition of vasodilatation mediated by nitric oxide (NO), endothelium-derived hyperpolarizing factor (EDHF) and prostacyclin, and activation of vasoconstriction mediated by endothelin-1 (ET-1), prostaglandin E2 (PGE2) and thromboxane A2 (TXA2). Activated PKC in DM also increases vascular endothelial growth factor (VEGF) expression and activates NADPH oxidases leading to raised ROS production. On the other hand, PKC in DM is involved in enhancement of vascular contractility in an endothelium-independent manner by inactivation of K(+) channels and Ca(2+) sensitization of myofilaments in vascular smooth muscle cells. This shows that PKC is a potential therapeutic target for treating vascular diabetic complications.International journal of cardiology 04/2014; 174:230-242. · 6.18 Impact Factor
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ABSTRACT: Diabetes exacerbates abnormal vascular smooth muscle cell (VSMC) accumulation in response to arterial wall injury. Vinpocetine has been shown to improve vascular remolding; however, little is known about the direct effects of vinpocetine on vascular complications mediated by diabetes. The objective of this study was to determine the effects of vinpocetine on hyperglycemia-facilitated neointimal hyperplasia and explore its possible mechanism. Nondiabetic and diabetic rats were subjected to balloon injury of the carotid artery followed by 3-week treatment with either vinpocetine (10 mg/kg/day) or saline. Morphological analysis and proliferating cell nuclear antigen (PCNA) immunostaining were performed on day 21. Rat VSMCs proliferation was determined with 5-ethynyl-20-deoxyuridine cell proliferation assays. Chemokinesis was monitored with scratch assays, and production of reactive oxygen species (ROS) was assessed using a 2',7'-dichlorodihydrofluorescein diacetate (H2DCFDA) flow cytometric assay. Apoptosis was detected by annexin V-FITC/PI flow cytometric assay. Cell signaling was assessed by immunblotting. Vinpocetine prevented intimal hyperplasia in carotid arteries in both normal (I/M ratio: 93.83 ± 26.45% versus 143.2 ± 38.18%, P<0.05) and diabetic animals (I/M ratio: 120.5 ± 42.55% versus 233.46 ± 33.98%, P<0.05) when compared to saline. The in vitro study demonstrated that vinpocetine significantly inhibited VSMCs proliferation and chemokinesis as well as ROS generation and apoptotic resistance, which was induced by high glucose (HG) treatment. Vinpocetine significantly abolished HG-induced phosphorylation of Akt and JNK1/2 without affecting their total levels. For downstream targets, HG-induced phosphorylation of IκBα was significantly inhibited by vinpocetine. Vinpocetine also attenuated HG-enhanced expression of PCNA, cyclin D1 and Bcl-2. Vinpocetine attenuated neointimal formation in diabetic rats and inhibited HG-induced VSMCs proliferation, chemokinesis and apoptotic resistance by preventing ROS activation and affecting MAPK, PI3K/Akt, and NF-κB signaling.PLoS ONE 01/2014; 9(5):e96894. · 3.53 Impact Factor