Human Aortic Smooth Muscle Cells Migration Research Articles

Abstract 17078: A Potent Vasoconstrictor Kisspeptin-10 Induces Atherosclerotic Plaque Progression and Instability

Background: Recently, there is a great deal of research interest regarding the role and effects of kisspeptin-10 (KP-10), a potent vasoconstrictor and inhibitor of angiogenesis expressed in vascular endothelial cells (ECs), in cardiovascular disease. However, it still remains unknown whether KP-10 could affect atherogenesis. Objective and Methods: We aimed to clarify the effects of KP-10 on atherosclerosis. We evaluated the effects of KP-10 on human umbilical vein endothelial cells (HUVECs), human monocyte-derived macrophages, human aortic smooth muscle cells (HASMCs) in vitro , and aortic lesions in ApoE -/- mice in vivo . Results: GPR54, a KP-10 receptor, was expressed at higher levels in human monocytes, macrophages, HASMCs, and HUVECs. KP-10 significantly suppressed the proliferation of EAhy.926 ECs. KP-10 significantly increased the adhesion of THP1 monocytes to HUVECs associated with increased endothelial expressions of IL-6, MCP-1, TNF-α, ICAM-1, VCAM-1, and E-selectin. KP-10 significantly enhanced oxidized low-density lipoprotein-induced foam cell formation associated with increased expressions of CD36 and acyl-CoA:cholesterol acyltransferase-1 in human monocyte-derived macrophages. KP-10 significantly suppressed the migration and proliferation of HASMCs with inducing apoptosis via AKT, p38, and bax upregulation, but significantly enhanced the activities of MMP-2 and MMP-9 in HASMCs. Four-week-infusion of KP-10 into ApoE -/- mice significantly accelerated the development of aortic atherosclerotic lesions with increased monocyte/macrophage infiltration. Conclusions: Our results indicate that KP-10 accelerates atherogenesis by enhancing EC inflammatory responses and macrophage foam cell formation, In addition, KP-10 suppresses EC proliferation, VSMC migration and proliferation, but enhances MMP-2 and MMP-9 activities in VSMCs, which may contribute to plaque instability, leading to plaque rupture. Thus, KP-10 may serve as a novel therapeutic target for acute coronary syndrome.

Abstract 10859: Preventive Effects of Neopterin on Atherosclerosis

Introduction: Neopterin, a GTP metabolite produced by activated macrophages after stimulation by interferon-γ released by T cells, is expressed at high levels in the carotid atherosclerotic lesions in patients with angina pectoris. However, the modulatory effect of neopterin on atherogenesis has not yet been reported. Objective and Methods: We aimed to clarify the effects of neopterin on atherogenesis. We investigated the atheroprotective effects of neopterin on human umbilical vein endothelial cells (HUVECs), human monocyte-derived macrophages, human aortic smooth muscle cells (HASMCs) in vitro , and aortic lesions in ApoE -/- mice in vivo . Plasma neopterin levels were compared between 25 patients with acute coronary syndrome (ACS) and 15 healthy volunteers. Results: Neopterin attenuated TNF-α-mediated monocyte adhesion to HUVECs. Neopterin suppressed TNF-α-induced upregulation of MCP-1, ICAM-1, and VCAM-1 in HUVECs. Neopterin shifted the phenotype overwhelmingly to anti-inflammatory M2 rather than inflammatory M1 via NF-κB downregulation during differentiation of human monocytes into macrophages. Neoptein significantly suppressed oxidized LDL-induced foam cell formation associated with reduced CD36 expression and increased both expressions and activities of ABCA1 and ABCG1 in human monocyte-derived macrophages. Neopterin significantly suppressed angiotensin II-induced migration of HASMCs, but increased fibronectin and MMP2 expressions accompanied with enhanced MMP2 activity in HASMCs. Four-week-infusion of neopterin into ApoE -/- mice significantly retarded the development of aortic atherosclerotic lesions with reduced monocyte/macrophage infiltration and lowered plasma levels of total cholesterol. In addition, plasma neopterin levels were markedly increased in ACS patients than healthy volunteers, suggesting that neopterin increased to counteract the formation of atherothrombosis. Conclusions: Our results indicate that neopterin prevents atherogenesis by suppressing monocyte adhesion to endothelial cells, macrophage foam cell formation, and VSMC migration. Thus, neopterin could serve as a novel therapeutic target and potential biomarker for atherosclerotic cardiovascular diseases.

PLCβ3 mediates cortactin interaction with WAVE2 in MCP1-induced actin polymerization and cell migration.

Monocyte chemotactic protein 1 (MCP1) stimulates vascular smooth muscle cell (VSMC) migration in vascular wall remodeling. However, the mechanisms underlying MCP1-induced VSMC migration have not been understood. Here we identify the signaling pathway associated with MCP1-induced human aortic smooth muscle cell (HASMC) migration. MCP1, a G protein-coupled receptor agonist, activates phosphorylation of cortactin on S405 and S418 residues in a time-dependent manner, and inhibition of its phosphorylation attenuates MCP1-induced HASMC G-actin polymerization, F-actin stress fiber formation, and migration. Cortactin phosphorylation on S405/S418 is found to be critical for its interaction with WAVE2, a member of the WASP family of cytoskeletal regulatory proteins required for cell migration. In addition, the MCP1-induced cortactin phosphorylation is dependent on PLCβ3-mediated PKCδ activation, and siRNA-mediated down-regulation of either of these molecules prevents cortactin interaction with WAVE2, affecting G-actin polymerization, F-actin stress fiber formation, and HASMC migration. Upstream, MCP1 activates CCR2 and Gαq/11 in a time-dependent manner, and down-regulation of their levels attenuates MCP1-induced PLCβ3 and PKCδ activation, cortactin phosphorylation, cortactin-WAVE2 interaction, G-actin polymerization, F-actin stress fiber formation, and HASMC migration. Together these findings demonstrate that phosphorylation of cortactin on S405 and S418 residues is required for its interaction with WAVE2 in MCP1-induced cytoskeleton remodeling, facilitating HASMC migration.

Brahma-related gene 1 inhibits proliferation and migration of human aortic smooth muscle cells by directly up-regulating Ras-related associated with diabetes in the pathophysiologic processes of aortic dissection

ObjectiveTo elucidate the mechanisms of Brahma-related gene 1 (Brg1) involvement in the pathophysiologic processes of aortic dissection. MethodsSeventeen dissecting, 4 dilated, and 10 healthy human aorta samples were collected. Expression of Brg1 in the medium of aorta was evaluated by quantitative real-time polymerase chain reaction, Western blot, and immunohistochemical staining, respectively. The regulation effect of Brg1 on proliferation and migration of human aortic smooth muscle cells (HASMCs) was analyzed in 3 ways: using cell counting, a migration chamber, and a wound scratch assay. A polymerase chain reaction array was used for screening potential target genes of Brg1. A chromatin immunoprecipitation assay was adopted for direct deoxyribonucleic acid–protein binding detection. ResultsExpression levels of Brg1 were increased in aortic dissection and aortic dilation patients. In vitro results indicated that overexpression of Brg1 inhibited proliferation and migration of HASMCs. The candidate proliferation- and migration-related Brg1 target gene found was Ras-related associated with diabetes (RRAD), expression levels of which were enhanced in dissecting aortic specimens. The direct regulation effect of Brg1 on RRAD was verified by chromatin immunoprecipitation assay results. Furthermore, down-regulating RRAD significantly alleviated the suppression effects of Brg1 on proliferation and migration of HASMCs. ConclusionsOur study illustrated that Brg1 inhibited the proliferation and migration capacity of HASMCs, via the mechanism of direct up-regulation of RRAD, thus playing an important role in the pathophysiologic processes of aortic dissection.

Abstract 719: PFKFB3 Mediated Glycolysis in Vascular Smooth Muscle Cells Is Essential for Arterial Neointima Formation

Background: Mature vascular smooth muscle cells (VSMCs) exhibit limited proliferation and migration ability. However, in response to stresses, VSMCs undergo phenotypic modulation characterized by increased proliferation and motility. This phenotypic modulation is associated with several vascular diseases, including atherosclerosis, arterial neointima formation. Elevated glycolysis has been described in proliferative VSMCs. The isoform 3 of 6-phosphofructo-2-kinase/fructose-2, 6-bisphosphatase (PFKFB3) is a regulatory factor for VSMC glycolysis. PFKFB3 catalyze the synthesis of fructose 2, 6-bishosphate (F2, 6 BP). The latter is a powerful activator of 6-phosphofructo-1-kinase, the rate-limiting enzyme in glycolytic flux. It is unclear whether PFKFB3 mediated glycolysis play a role in VSMC phenotypic modulation andarterial neointima formation. Methods and results: PDGF treatment increased PFKFB3 expression in human aortic smooth muscle cells (HASMCs). This was accompanied with enhanced proliferation and migration of HASMCs. Knockdown of PFKFB3 with adenovirus carrying PFKFB3 short hairpin RNA suppressed PDGF-induced HASMC proliferation and migration. Examination of intracellular signaling indicated PI3K/Akt participated into PFKFB3-mediated glycolysis, and further cooperated with PFKFB3 to modulate phenotype of HASMCs. In a model of the left common carotid artery ligation, both PFKFB3 heterozygotes and mice with deficiency of PFKFB3 in VSMCs showed the decreased arterial neointima compared with controls mice. Conclusions: PFKFB3 mediates glycolysis and cooperates with PI3K/AKT, thereafter promoting proliferation and migration of VSMCs and leading to the formation of an increased arterial neointima. Thus, PFKFB3 is a promising therapeutic target for the treatment of atherosclerosis, arterial neointima and other peripheral arterial diseases.

Overexpression of mimecan in human aortic smooth muscle cells inhibits cell proliferation and enhances apoptosis and migration.

The pathogenesis of atherosclerosis is multifactorial. The proliferation and migration of vascular smooth muscle cells (VSMCs) are significant in the genesis and development of atherosclerosis plaques, and the degradation of VSMCs plays a crucial role in the process. Mimecan is a member of the Keratan sulfate family of proteoglycans, which are leucine-rich proteoglycans. It has been demonstrated that mimecan is associated with arteriogenesis and atherosclerosis. In the present study, the effect of mimecan on the characteristics of cultured human aortic smooth muscle cells (HASMCs) was investigated. In vitro, human mimecan was stably overexpressed in HASMCs using a lentiviral system. It was observed that the proliferation rate of HASMCs transduced with mimecan was lower compared with that of control cells; overexpression of mimecan induced HASMC apoptosis. To determine the effect of mimecan on HASMC migration, a Transwell cell culture chamber and sterile cloning cylinder assays were used, and it was noted that mimecan enhanced the migration of HASMCs horizontally and vertically. These data indicated that mimecan may be involved in the pathogenesis of atherosclerosis by regulating the proliferation, apoptosis and migration of VSMCs.

Dihydroaustrasulfone alcohol inhibits PDGF-induced proliferation and migration of human aortic smooth muscle cells through inhibition of the cell cycle.

Dihydroaustrasulfone alcohol is the synthetic precursor of austrasulfone, which is a marine natural product, isolated from the Taiwanese soft coral Cladiella australis. Dihydroaustrasulfone alcohol has anti-inflammatory, neuroprotective, antitumor and anti-atherogenic properties. Although dihydroaustrasulfone alcohol has been shown to inhibit neointima formation, its effect on human vascular smooth muscle cells (VSMCs) has not been elucidated. We examined the effects and the mechanisms of action of dihydroaustrasulfone alcohol on proliferation, migration and phenotypic modulation of human aortic smooth muscle cells (HASMCs). Dihydroaustrasulfone alcohol significantly inhibited proliferation, DNA synthesis and migration of HASMCs, without inducing cell death. Dihydroaustrasulfone alcohol also inhibited platelet-derived growth factor (PDGF)-induced expression of cyclin-dependent kinases (CDK) 2, CDK4, cyclin D1 and cyclin E. In addition, dihydroaustrasulfone alcohol inhibited PDGF-induced phosphorylation of extracellular signal-regulated kinase 1/2 (ERK1/2), whereas it had no effect on the phosphorylation of phosphatidylinositol 3-kinase (PI3K)/(Akt). Moreover, treatment with PD98059, a highly selective ERK inhibitor, blocked PDGF-induced upregulation of cyclin D1 and cyclin E and downregulation of p27kip1. Furthermore, dihydroaustrasulfone alcohol also inhibits VSMC synthetic phenotype formation induced by PDGF. For in vivo studies, dihydroaustrasulfone alcohol decreased smooth muscle cell proliferation in a rat model of restenosis induced by balloon injury. Immunohistochemical staining showed that dihydroaustrasulfone alcohol noticeably decreased the expression of proliferating cell nuclear antigen (PCNA) and altered VSMC phenotype from a synthetic to contractile state. Our findings provide important insights into the mechanisms underlying the vasoprotective actions of dihydroaustrasulfone alcohol and suggest that it may be a useful therapeutic agent for the treatment of vascular occlusive disease.

Essential oils purified from Schisandrae semen inhibits tumor necrosis factor-α-induced matrix metalloproteinase-9 activation and migration of human aortic smooth muscle cells.

BackgroundThe migration of vascular smooth muscle cells from the tunica media to the subendothelial region may be a key event in the development of atherosclerosis after arterial injury. In this study, we investigated the potential mechanisms underlying the anti-atherosclerotic effects of Schisandrae Semen essential oil (SSeo) in human aortic smooth muscle cells (HASMCs).MethodsMetalloproteinase-2/9 (MMP-2/9) activity was evaluated by gelatin zymography and gelatinase activity assay kit. The possible mechanisms underlying SSeo-mediated reduction of by tumor necrosis factor (TNF)-α-induced cell invasion and inhibition of secreted and cytosolic MMP-9 production in HASMCs were investigated.ResultsOur results indicate that SSeo treatment has an inhibitory effect on activation as well as expression of MMP-9 induced by TNF-α in HASMCs in a dose-dependent manner without significant cytotoxicity. SSeo attenuated nuclear translocation of TNF-α-mediated nuclear factor-kappa B (NF-κB) and blocked degradation of the NF-κB inhibitor proteins as well as the production of reactive oxygen species. SSeo also reduced TNF-α-induced production of pro-inflammatory mediators such as nitric oxide and prostaglandin E2 and inhibited inducible nitric oxide synthase and cyclooxygenase-2 expression in HASMCs. Furthermore, the Matrigel migration assay showed that SSeo effectively reduced TNF-α-induced HASMC migration compared with that in the control group.ConclusionsTaken together, these results suggest that SSeo treatment suppresses TNF-α-induced HASMC migration by selectively inhibiting MMP-9 expression, which was associated with suppression of the NF-κB signaling pathway. Taken together, these results suggest that SSeo has putative potential anti-atherosclerotic activity.

Statins meditate anti-atherosclerotic action in smooth muscle cells by peroxisome proliferator-activated receptor-γ activation

The peroxisome proliferator-activated receptor-γ (PPARγ) is an important regulator of lipid and glucose metabolism, and its activation is reported to suppress the progression of atherosclerosis. We have reported that 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors (statins) activate PPARγ in macrophages. However, it is not yet known whether statins activate PPARγ in other vascular cells. In the present study, we investigated whether statins activate PPARγ in smooth muscle cells (SMCs) and endothelial cells (ECs) and thus mediate anti-atherosclerotic effects. Human aortic SMCs (HASMCs) and human umbilical vein ECs (HUVECs) were used in this study. Fluvastatin and pitavastatin activated PPARγ in HASMCs, but not in HUVECs. Statins induced cyclooxygenase-2 (COX-2) expression in HASMCs, but not in HUVECs. Moreover, treatment with COX-2-siRNA abrogated statin-mediated PPARγ activation in HASMCs. Statins suppressed migration and proliferation of HASMCs, and inhibited lipopolysaccharide-induced expression of monocyte chemoattractant protein-1 (MCP-1) and tumor necrosis factor-α (TNF-α) in HASMCs. These effects of statins were abrogated by treatment with PPARγ-siRNA. Treatment with statins suppressed atherosclerotic lesion formation in Apoe−/− mice. In addition, transcriptional activity of PPARγ and CD36 expression were increased, and the expression of MCP-1 and TNF-α was decreased, in the aorta of statin-treated Apoe−/− mice. In conclusion, statins mediate anti-atherogenic effects through PPARγ activation in SMCs. These effects of statins on SMCs may be beneficial for the prevention of atherosclerosis.

Berberine suppresses in vitro migration of human aortic smooth muscle cells through the inhibitions of MMP-2/9, u-PA, AP-1, and NF-κB

Berberine, a type of isoquinoline alkaloid isolated from Chinese medicinal herbs, has been reported to have various pharmacological activities. Studies have demonstrated that berberine has beneficial effects on vascular remodeling and alleviates restenosis after vascular injury. However, its mechanism of action on vascular smooth muscle cell migration is not fully understood. We therefore investigated the effect of berberine on human aortic smooth muscle cell (HASMC) migration. Boyden chamber assay was performed to show that berberine inhibited HASMC migration dosedependently. Real-time PCR and Western blotting analyses showed that levels of matrix metalloproteinase (MMP)-2, MMP-9, and urokinase-type plasminogen activator (u-PA) were reduced by berberine at both the mRNA and protein levels. Western blotting assay further confirmed that activities of c-Fos, c-Jun, and NF-κB were significantly attenuated. These results suggest that berberine effectively inhibited HASMC migration, possibly by down-regulating MMP-2, MMP-9, and u-PA; and interrupting AP-1 and NF-κB mediated signaling pathways. [BMB Reports 2014; 47(7): 388-392]

NFATc1 mediates Pak1 activation in the modulation of chemokine‐induced human aortic smooth muscle cell F‐actin stress fiber formation, migration, and proliferation and injury‐induced vascular wall remodeling (1158.5)

In addition to their role in cell proliferation, cyclin‐dependent kinases (CDKs) mediate cell migration; however the underlying mechanisms are not clear. Therefore, the objective of this study is to test whether cyclin/CDKs activate Pak1, an effector of Rac1, whose involvement in the modulation of cell migration and proliferation is well established. Monocyte chemotactic protein 1 (MCP1) induced Pak1 phosphorylation/activation in human aortic smooth muscle cells (HASMCs) in a time‐dependent but delayed manner. MCP1 also stimulated F‐actin stress fiber formation as well as the migration and proliferation of these cells and inhibition of Pak1 reversed these effects. MCP1 also induced cyclin D1 expression and CDK6/4 activities, and these effects were dependent on NFATc1 activation. Depletion of NFATc1, cyclin D1, CDK6, or CDK4 levels attenuated MCP1‐induced Pak1 phosphorylation/activation resulting in decreased HASMC F‐actin stress fiber formation, migration and proliferation. CDK4, which appeared to be activated downstream of CDK6, formed a complex with Pak1 in response to MCP1. Depletion/inhibition of Rac1 levels/activation abrogated MCP1‐induced NFATc1‐cyclin D1‐CDK6‐CDK4‐Pak1 signaling, and thereby, decreased HASMC F‐actin stress fiber formation, migration, and proliferation. In addition, smooth muscle‐specific deletion of NFATc1 led to decreased cyclin D1 expression and CDK6, CDK4, and Pak1 activities resulting in reduced neointima formation in response to injury. Thus, these observations reveal that Pak1 is a downstream effector of CDK4 and Rac1‐dependent NFATc1‐mediated cyclin D1 expression and CDK6 activity mediate this effect in the modulation of MCP1‐induced HASMC migration and proliferation in vitro and vascular wall remodeling in vivo.Grant Funding Source: NHLBI

Pelargonidin attenuates PDGF-BB-induced aortic smooth muscle cell proliferation and migration by direct inhibition of focal adhesion kinase

Pelargonidin is a natural red pigment found in fruits and vegetables, and has been reported to exhibit various effects potentially beneficial for human health. However, the possible preventive effects of pelargonidin toward atherosclerosis and mechanisms involved have not been investigated to date. Here, we compared the effects of pelargonidin and its glucoside-conjugated form, pelargonidin-3-glucoside (P3G), on proliferation and migration induced by platelet-derived growth factor (PDGF)-BB in human aortic smooth muscle cells (HASMCs). Pelargonidin, but not P3G, exhibited strong inhibitory effects against PDGF-BB-induced HASMC proliferation and migration, while suppressing PDGF-BB-induced ex vivo rat aortic ring sprouting. Immunoblot analysis revealed that pelargonidin inhibited PDGF-BB-induced phosphorylation of focal adhesion kinase (FAK) as well as F-actin reduction, whereas Src, mitogen-activated protein kinases (MAPKs) and Akt phosphorylation status were not altered. We also observed that the anti-proliferative and migratory effects of both pelargonidin and P3G corresponded with the extent of FAK inhibition. Both in vitro and ex vivo pull-down assays revealed that pelargonidin binds directly with FAK in an adenosine triphosphate-competitive manner, suggesting that FAK could be a molecular target of pelargonidin. Interestingly, pelargonidin did not exhibit inhibitory effects on the proliferation, migration or FAK phosphorylation of human umbilical vein endothelial cells (HUVECs). Taken together, our results suggest that pelargonidin exhibits potential preventive effects toward atherosclerosis through the attenuation of HASMC proliferation and migration, as well as aortic sprouting via the direct inhibition of FAK activity.

Anthocyanidins, novel FAK inhibitors, attenuate PDGF-BB-induced aortic smooth muscle cell migration and neointima formation

Abnormal migration of human aortic smooth muscle cells (HASMCs) causes intimal thickening of the aorta, a pivotal step in atherosclerotic development. Although many studies have demonstrated that high anthocynidins intake confers protective effects against atherosclerosis, the direct molecular targets, and mechanisms of action responsible remain unclear. Here, we investigated the preventive effect of anthocyanidins on atherosclerosis and the underlying mechanisms involved. We analysed six major anthocyanidins, and found that petunidin exhibited the most potent inhibitory effects against platelet-derived growth factor (PDGF)-BB-induced HASMC migration in the Boyden chamber and wound healing assays. Petunidin also suppressed PDGF-BB-induced ex vivo rat aortic sprouting and in vivo rat neointima formation. Western blot analysis showed that petunidin inhibited PDGF-BB-induced phosphorylation of focal adhesion kinase (FAK) at the low concentration of 5 µM, whereas phosphorylation of Src, mitogen-activated protein kinases, and Akt was only slightly inhibited at 20 µM. In vitro and ex vivo FAK activity assays demonstrated that petunidin directly suppresses FAK activity by binding in an ATP non-competitive manner. Moreover, anthocyanidins that reduced HASMC migration also inhibited PDGF-BB-induced FAK phosphorylation, F-actin reduction, and FAK activity, and directly bound with FAK. PDGF-BB-induced migration, F-actin reduction by HASMCs, and ex vivo aortic sprouting were all inhibited by treatment with a commercial FAK inhibitor, PF-228. The results of the present study demonstrate that anthocyanidins can directly bind with and suppress the activity of FAK with atherosclerosis-preventive effects.

Protective effect of the ultra-filtration extract from Xin Mai Jia on human aortic smooth muscle cell injury induced by hydrogen peroxide

The aim of the present study was to explore whether an ultra-filtration extract from Xin Mai Jia (XMJ), a Chinese medicinal formulation, has a protective effect on human aortic smooth muscle cell (HASMC) injury models induced by hydrogen peroxide (H2O2), and to consider the mechanism and efficacy of the therapeutic action of XMJ on atherosclerosis. HASMCs were injured by H2O2 and then exposed to various concentrations of XMJ. The morphological changes, growth, proliferation, migration and cytokine release of HASMCs were detected using 2,3-bis-(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide (XTT), an enzyme-linked immunosorbent assay and a scratch adhesion test. H2O2 significantly promoted the proliferation of HASMCs. The ultra-filtration extract from XMJ was observed to significantly attenuate the morphological changes of injured HASMCs, reduce the expression levels of intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1), interleukin (IL)-1, IL-6 and nuclear factor (NF)-κB, and increase the expression levels of matrix metalloproteinase (MMP)-2 and tissue inhibitor of metalloproteinase (TIMP). XMJ has clear anti-inflammatory and antioxidant effects, and significantly inhibits the proliferation and migration of HASMCs.

Lipocalin-2 elicited by advanced glycation end-products promotes the migration of vascular smooth muscle cells

Advanced glycation end-products (AGEs) play key roles in the development of diabetic vascular complications by activating the proliferation and migration of vascular smooth muscle cells. Here, we identified an increase of the migratory properties of human aortic smooth muscle cells (HASMC) through AGE-induced expression of lipocalin-2 (LCN2). Because the AGE-elicited expression of LCN2 was diminished by an antibody against the AGE receptor (RAGE), diphenylene iodonium (DPI), N-acetyl cysteine, LY294002, and SP600125, we suggest that AGEs enhance the expression of LCN2 via a RAGE-NADPH oxidase-reactive oxygen species pathway, leading to the phosphorylation of PI3K-Akt and JNK in HASMCs. In addition, a chromatin immunoprecipitation assay and promoter assay revealed that CCAAT/enhancer binding protein β is crucial for AGE-induced expression of LCN2. However, any other AGE-related signaling pathway, including ERK1/2, p38, NF-κB, and AP-1, did not affect the AGE- induced expression of LCN2. Knockdown of LCN2 expression by shRNA showed that AGE-elicited LCN2 expression enhanced the invasive and migratory properties of HASMCs, but showed no effect on cell proliferation. Considering the importance of HASMC migration in the development of atherosclerosis, our study provides a novel insight into diabetic vascular complications.

Nuclear Factor of Activated T Cells c1 Mediates p21-activated Kinase 1 Activation in the Modulation of Chemokine-induced Human Aortic Smooth Muscle Cell F-actin Stress Fiber Formation, Migration, and Proliferation and Injury-induced Vascular Wall Remodeling

Recent literature suggests that cyclin-dependent kinases (CDKs) mediate cell migration. However, the mechanisms were not known. Therefore, the objective of this study is to test whether cyclin/CDKs activate Pak1, an effector of Rac1, whose involvement in the modulation of cell migration and proliferation is well established. Monocyte chemotactic protein 1 (MCP1) induced Pak1 phosphorylation/activation in human aortic smooth muscle cells (HASMCs) in a delayed time-dependent manner. MCP1 also stimulated F-actin stress fiber formation in a delayed manner in HASMCs, as well as the migration and proliferation of these cells. Inhibition of Pak1 suppressed MCP1-induced HASMC F-actin stress fiber formation, migration, and proliferation. MCP1 induced cyclin D1 expression as well as CDK6 and CDK4 activities, and these effects were dependent on activation of NFATc1. Depletion of NFATc1, cyclin D1, CDK6, or CDK4 levels attenuated MCP1-induced Pak1 phosphorylation/activation and resulted in decreased HASMC F-actin stress fiber formation, migration, and proliferation. CDK4, which appeared to be activated downstream of CDK6, formed a complex with Pak1 in response to MCP1. MCP1 also activated Rac1 in a time-dependent manner, and depletion/inhibition of its levels/activation abrogated MCP1-induced NFATc1-cyclin D1-CDK6-CDK4-Pak1 signaling and, thereby, decreased HASMC F-actin stress fiber formation, migration, and proliferation. In addition, smooth muscle-specific deletion of NFATc1 led to decreased cyclin D1 expression and CDK6, CDK4, and Pak1 activities, resulting in reduced neointima formation in response to injury. Thus, these observations reveal that Pak1 is a downstream effector of CDK4 and Rac1-dependent, NFATc1-mediated cyclin D1 expression and CDK6 activity mediate this effect. In addition, smooth muscle-specific deletion of NFATc1 prevented the capacity of vascular smooth muscle cells for MCP-1-induced activation of the cyclin D1-CDK6-CDK4-Pak1 signaling axis, affecting their migration and proliferation in vitro and injury-induced neointima formation in vivo.

Persimmon peel extract attenuates PDGF-BB-induced human aortic smooth muscle cell migration and invasion through inhibition of c-Src activity

The unregulated migration and invasion of human aortic smooth muscle cells (HASMCs) into the intima is a crucial step in the development of atherosclerosis. Recently, the oriental persimmon extract (Diospyros kaki Thunb. cv. Fuyu) has been investigated for its anti-atherogenic properties, but the molecular mechanisms involved remain unclear. We investigated the inhibitory effects of persimmon peel and flesh extract on the platelet-derived growth factor (PDGF) BB-induced MMP-1 expression using Western blot, and abnormal migration and invasion of HASMCs using a modified Boyden chamber assay and a wound healing assay. We also evaluated the inhibitory effects of persimmon peel extract on aortic vessel thickening using a rat aortic sprouting assay. Persimmon peel (PPE), but not flesh extract (PFE), inhibited PDGF-BB-induced MMP-1 expression, cell migration and invasion in HASMCs, while suppressing the rat aortic sprouting. Western blot and in vitro kinase assay data demonstrated that PPE inhibited Src kinase activity and subsequently attenuated PDGF-BB-induced phosphorylation of MAPK and Akt signalling pathways. Taken together, our results indicate that persimmon peel might possess a potential anti-atherogenic effect through attenuation of ASMCs migration and invasion and aortic sprouting by direct inhibition of the c-Src kinase activity.

Cortistatin Inhibits Migration and Proliferation of Human Vascular Smooth Muscle Cells and Decreases Neointimal Formation on Carotid Artery Ligation

Proliferation and migration of smooth muscle cells (SMCs) are key steps for the progression of atherosclerosis and restenosis. Cortistatin is a multifunctional neuropeptide belonging to the somatostatin family that exerts unique functions in the nervous and immune systems. Cortistatin is elevated in plasma of patients experiencing coronary heart disease and attenuates vascular calcification. To investigate the occurrence of vascular cortistatin and its effects on the proliferation and migration of SMCs in vitro and in vivo and to delimitate the receptors and signal transduction pathways governing its actions. SMCs from mouse carotid and human aortic arteries and from human atherosclerotic plaques highly expressed cortistatin. Cortistatin expression positively correlated with the progression of arterial intima hyperplasia. Cortistatin inhibited platelet-derived growth factor-stimulated proliferation of human aortic SMCs via binding to somatostatin receptors (sst2 and sst5) and ghrelin receptor, induction of cAMP and p38-mitogen-activated protein kinase, and inhibition of Akt activity. Moreover, cortistatin impaired lamellipodia formation and migration of human aortic SMCs toward platelet-derived growth factor by inhibiting, in a ghrelin-receptor-dependent manner, Rac1 activation and cytosolic calcium increases. These effects on SMC proliferation and migration correlated with an inhibitory action of cortistatin on the neointimal formation in 2 models of carotid arterial ligation. Endogenous cortistatin seems to play a critical role in regulating SMC function because cortistatin-deficient mice developed higher neointimal hyperplasic lesions than wild-type mice. Cortistatin emerges as a natural endogenous regulator of SMCs under pathological conditions and an attractive candidate for the pharmacological management of vascular diseases that course with neointimal lesion formation.

Protein Kinase N1 Is a Novel Substrate of NFATc1-mediated Cyclin D1-CDK6 Activity and Modulates Vascular Smooth Muscle Cell Division and Migration Leading to Inward Blood Vessel Wall Remodeling

Toward understanding the mechanisms of vascular wall remodeling, here we have studied the role of NFATc1 in MCP-1-induced human aortic smooth muscle cell (HASMC) growth and migration and injury-induced rat aortic wall remodeling. We have identified PKN1 as a novel downstream target of NFATc1-cyclin D1/CDK6 activity in mediating vascular wall remodeling following injury. MCP-1, a potent chemoattractant protein, besides enhancing HASMC motility, also induced its growth, and these effects require NFATc1-dependent cyclin D1 expression and CDK4/6 activity. In addition, MCP-1 induced PKN1 activation in a sustained and NFATc1-cyclin D1/CDK6-dependent manner. Furthermore, PKN1 activation is required for MCP-1-induced HASMC growth and migration. Balloon injury induced PKN1 activation in NFAT-dependent manner and pharmacological or dominant negative mutant-mediated blockade of PKN1 function or siRNA-mediated down-regulation of its levels substantially suppressed balloon injury-induced smooth muscle cell migration and proliferation resulting in reduced neointima formation. These novel findings suggest that PKN1 plays a critical role in vascular wall remodeling, and therefore, it could be a promising new target for the next generation of drugs for vascular diseases, particularly restenosis following angioplasty, stent implantation, or vein grafting.

Melittin has an inhibitory effect on TNF-α-induced migration of human aortic smooth muscle cells by blocking the MMP-9 expression

Matrix metalloproteinases-9 (MMP-9) plays an important role in the pathogenesis of atherosclerosis and migration of vascular smooth muscle cells (VSMCs) after an arterial injury. In this study, we investigated the potential molecular mechanisms underlying the anti-atheroscleroic effects of melittin, a major component of bee venom, in human aortic smooth muscle cells (HASMCs). Melttin significantly suppressed MMP-9 and MMP-2 secretion, as well as TNF-α-induced MMP-9 expression in the HASMCs. In addition, we found that the inhibitory effects of melittin on TNF-α-induced MMP-9 protein expression are associated with the inhibition of MMP-9 transcription levels. Mechanistically, Melittin suppressed TNF-α-induced MMP-9 activity by inhibiting the phosphorylation of p38 and ERK1/2, but did not affect the phosphorylation of JNK and Akt. Reporter gene and western blotting assays showed that melittin inhibits MMP-9 transcriptional activity by blocking the activation of NF-κB via IκBα signaling pathway. Moreover, the matrigel migration assay showed that melittin reduced TNF-α-induced HASMC migration. These results suggest that melittin suppresses TNF-α-induced HASMC migration through the selective inhibition of MMP-9 expression and provide a novel role of melittin in the anti-atherosclerotic action.