Sesamin Inhibits PDGF-Mediated Proliferation of Vascular Smooth Muscle Cells by Upregulating p21 and p27

Isolation and Cultivation of Vascular Smooth Muscle Cells from the Mouse Circle of Willis

INTRODUCTION

Culturing cerebrovascular smooth muscle cells (CVSMCs) in vitro can provide a model for studying many cerebrovascular diseases. This study describes a convenient and efficient method to obtain mouse CVSMCs by enzyme digestion.

METHODS

Mouse circle of Willis was isolated, digested, and cultured with platelet-derived growth factor-BB (PDGF-BB) to promote CVSMC growth, and CVSMCs were identified by morphology, immunofluorescence analysis, and flow cytometry. The effect of PDGF-BB on vascular smooth muscle cell (VSMC) proliferation was evaluated by cell counting kit (CCK)-8 assay, morphological observations, Western blotting, and flow cytometry.

RESULTS

CVSMCs cultured in a PDGF-BB-free culture medium had a typical peak-to-valley growth pattern after approximately 14 days. Immunofluorescence staining and flow cytometry detected strong positive expression of the cell type-specific markers alpha-smooth muscle actin (α-SMA), smooth muscle myosin heavy chain 11 (SMMHC), smooth muscle protein 22 (SM22), calponin, and desmin. In the CCK-8 assay and Western blotting, cells incubated with PDGF-BB had significantly enhanced proliferation compared to those without PDGF-BB.

CONCLUSION

We obtained highly purified VSMCs from the mouse circle of Willis using simple methods, providing experimental materials for studying the pathogenesis and treatment of neurovascular diseases in vitro. Moreover, the experimental efficiency improved with PDGF-BB, shortening the cell cultivation period.

Inhibition of p90RSK Ameliorates PDGF-BB-Mediated Phenotypic Change of Vascular Smooth Muscle Cell and Subsequent Hyperplasia of Neointima

Platelet-derived growth factor type BB (PDGF-BB) regulates vascular smooth muscle cell (VSMC) migration and proliferation, which play critical roles in the development of vascular conditions. p90 ribosomal S6 kinase (p90RSK) can regulate various cellular processes through many different target substrates in several cell types, but the regulatory function of p90RSK on PDGF-BB-mediated cell migration and proliferation and subsequent vascular neointima formation has not yet been extensively examined. In this study, we investigated whether p90RSK inhibition protects VSMCs against PDGF-BB-induced cellular phenotypic changes and the molecular mechanisms underlying the effect of p90RSK inhibition on neointimal hyperplasia in vivo. Pretreatment of cultured primary rat VSMCs with FMK or BI-D1870, which are specific inhibitors of p90RSK, suppressed PDGF-BB-induced phenotypic changes, including migration, proliferation, and extracellular matrix accumulation, in VSMCs. Additionally, FMK and BI-D1870 repressed the PDGF-BB-induced upregulation of cyclin D1 and cyclin-dependent kinase-4 expression. Furthermore, p90RSK inhibition hindered the inhibitory effect of PDGF-BB on Cdk inhibitor p27 expression, indicating that p90RSK may induce VSMC proliferation by regulating the G0/G1 phase. Notably, treatment with FMK resulted in attenuation of neointima development in ligated carotid arteries in mice. The findings imply that p90RSK inhibition mitigates the phenotypic switch and neointimal hyperplasia induced by PDGF-BB.

The antinociceptive and anti-inflammatory potential and pharmacokinetic study of significant alkamides ingredients from Asarum Linn

ETHNOPHARMACOLOGICAL RELEVANCE

Asari Radix et Rhizoma (ARR), including 3 major plants of genus Asarum Linn, A. heterotropoides Fr. Schmidt var. mandshuricum (Maxim.) Kitag., A. sieboldii Miq. f. sieboldii and A. sieboldii Miq f. seoulense (Nakai) C. Y. Cheng et C. S. Yang, is one of the most important traditional herbal medicine in Asia with tremendous pharmacological activities. For a long time, researchers focus attention on studing asarinin and essential oils, the indicating ingredients of ARR, but paid less attention to another characteristic component, alkamides. The role of alkamides in the major efficacy of ARR medication remains to be elucidated.

AIM OF THE STUDY

This study aims to investigate the contribution of alkamides in the efficacy of ARR according to the evaluation of antinociceptive and anti-inflammatory effects and in vivo pharmacokinetics processes.

MATERIALS AND METHODS

For pharmacodynamic study, the analgesic and anti-inflammatory effects of alkamides-enriched fraction (ARRA) were comparatively evaluated by writhing test, hot plate test, and ear swelling test in mice after oral administration. For pharmacokinetic study, an UHPLC-MS/MS method was developed for the simultaneous determination of N-isobutyl-2E,4E,8Z,10Z/E-dodecatetraenamide (DDA) and other 6 major characteristic ingredients of ARR in rat plasma. The analytical method was validated and successfully applied to the pharmacokinetic study of ARR extract and DDA.

RESULTS

Pharmacodynamic study show that the ARR and ARRA can significantly inhibit the writhing times of mice caused by acetic acid administration, increase the pain threshold of thermal stimulation, and inhibit xylene treated ear swelling degree by reduce PGE₂ and TNF-α levels in the inflamed tissue. For pharmacokinetic study, the pharmacokinetic parameters of Vd/F and CL/F after intravenous administration in rats of DDA are 63.94 ± 32.12 L/kg and 0.33 ± 0.06 L/min/kg, respectively. The plasma drug concentration declined with the T_1/2 value of 2.25 ± 0.96 h, and the MRT_0-∞ was 2.23 ± 1.02 h. The absolute bioavailability of DDA after oral administration was calculated as 10.73%. DDA, methyleugenol, and asarinin have relatively high AUC_0-∞ values when the ethanol and water extract of ARR is orally administered.

CONCLUSIONS

ARRA is a kind of active ingredients with potential analgesic and anti-inflammatory effects that played a significant role in the major efficacy of ARR. DDA, the major compound of ARRA, has a high level of exposure in vivo, which could be is suitable for the pharmacokinetic marker or new quality marker of ARR.

A Comprehensive Review on Distribution, Pharmacological Properties, and Mechanisms of Action of Sesamin

Sesamin is a kind of fat-soluble lignan extracted from sesame seeds or other plants. It has attracted more and more attention because of its extensive pharmacological activities. In this study, we systematically summarized the pharmacological activities of sesamin including antioxidant, anti-inflammatory, anticancer, protection of liver and kidney, prevention of diabetes, hypertension, and atherosclerosis. Studies focus on the abilities of sesamin to attenuate oxidative stress by reducing the levels of ROS and MDA, to inhibit the release of pro-inflammatory cytokines (TNF-α, IL-1β, IL-6, etc.), and to induce apoptosis and autophagy in cancer cells through a variety of signaling pathways such as NF-κB, JNK, p38 MAPK, PI3K/AKT, caspase-3, and p53. By inhibiting the production of ROS, sesamin can also enhance the biological activities of NO in blood vessels, improve endothelial dysfunction and hypertension, and change the process of atherosclerotic lesion formation. In line with this, the various pharmacological properties of sesamin have been discussed in this review so that we can have a deeper understanding of the pharmacological activities of sesamin and clear the future development direction of sesamin.

The genus Asarum: A review on phytochemistry, ethnopharmacology, toxicology and pharmacokinetics

ETHNOPHARMACOLOGICAL RELEVANCE

In essentially every quadrant of the globe, many species of genus Asarum are used as a common herbal medicine and appear in many formulas or Kampo. Crude drug from several medicinal plants of genus Asarum (MA) known as Asari Radix et Rhizoma (ARR) has been proven to have the functions of dispelling cold, relieving pain, and reducing phlegm according to Traditional Chinese Medicine (TCM) theory for thousands of years.

AIM OF THE STUDY

This article reviews the ethnopharmacology, phytochemistry, pharmacology, toxicology and metabolic kinetics related research of genus Asarum to evaluate its ethnopharmacology use and future opportunities for research.

MATERIALS AND METHODS

Information on relevant studies of the genus Asarum was gathered via the Internet using Baidu Scholar, Web of Science, Elsevier, ResearchGate, ACS, Pudmed and Chinese National Knowledge Infrastructure (CNKI). Additionally, information was also obtained from some local books, PhD, MS's dissertations and Pharmacopeias.

RESULTS

The genus Asarum has played an important role in herbal treatment. At present, more than 277 compounds have been isolated or identified from genus Asarum. Among them, volatile oil and lignans are the major active constituents and important chemotaxonomic markers. Modern pharmacological studies indicated that genus Asarum and its active compounds possess a wide range of pharmacological effects, especially analgesic, anti-inflammatory, neuroprotective, cardiovascular protection, antitussive, immunosuppressive, anti-tumor, and microbicidal activities.

CONCLUSIONS

Based on this review, therapeutic potential of genus Asarum has been demonstrated with the pharmacological effects on inflammation, CNS, respiratory regulation, cardiovascular diseases, cancer and microbial infection. The available literature showed that the major activities of the genus Asarum can be attributed to the active lignans and essential oils. Further in-depth studies on the aspects of the genus for mechanism of actions, metabolism, pharmacokinetics, toxicology, drug interactions, and clinical trials are still limited, thereby intensive research and assessments should be performed.

Cytokine-induced apoptosis inhibitor 1 (CIAPIN1) accelerates vascular remodelling via p53 and JAK2-STAT3 regulation in vascular smooth muscle cells

BACKGROUND AND PURPOSE

Abnormal vascular smooth muscle cell (VSMC) proliferation and migration lead to neointima formation, which eventually results in cardiovascular hyperplastic diseases. The molecular mechanisms underlying these cellular processes have not been fully understood. Cytokine-induced apoptosis inhibitor 1 (CIAPIN1) has been identified as an anti-apoptotic molecule, but little is known about its target genes and related pathways in VSMC dysfunction or its clinical implication in neointima formation following vascular injury.

EXPERIMENTAL APPROACH

Determination, using loss/gain-of-function approaches by gene delivery, of whether CIAPIN1 modulates VSMC proliferation, migration and neointima formation and the underlying mechanisms was carried out. Balloon injury or ligation and local delivery of lentivirus were performed on rat or mouse carotid arteries. Rat aortic smooth muscle cells, the primary cell, was used as the model to evaluate the effect of CIAPIN1 on proliferation and migration.

KEY RESULTS

CIAPIN1 was overexpressed in the neointimal region of rat arteries. CIAPIN1 deficiency markedly inhibited injury-induced or ligation-induced intimal hyperplasia and suppressed PDGF-BB-induced VSMC proliferation, migration and cell cycle progression, while overexpression promoted proliferation, migration and neointima formation. CIAPIN1 negatively regulated Tp53 transcription, which promoted cell cycle progression and migration via cyclin E1-CDK2/pRb/PCNA and the MMP2 pathway. CIAPIN1 also increased JAK2 expression, enhancing JAK2 and STAT3 phosphorylation by vascular injury, which forced phenotypic switching from contractile to synthetic state in injured arteries.

CONCLUSIONS AND IMPLICATIONS

These findings provide new insights into the mechanism by which CIAPIN1 regulates vascular remodelling and suggest a novel therapeutic target for treating vascular proliferative diseases.

Regulation of autophagy by controlling Erk1/2 and mTOR for platelet-derived growth factor-BB-mediated vascular smooth muscle cell phenotype shift

AIMS

Vascular smooth muscle cell (VSMC) phenotype shift is involved in the pathophysiology of vascular injury or platelet-derived growth factor (PDGF)-induced abnormal proliferation and migration of VSMCs. We aimed to investigate the underlying mechanism involved in PDGF-mediated signaling pathways and autophagy regulation followed by VSMC phenotype shift.

MAIN METHODS

The proliferation, migration and apoptosis of cultured rat aortic VSMCs were measured, and cells undergoing phenotype shift and autophagy were examined. Specific inhibitors for target proteins in signaling pathways were applied to clarify their roles in regulating cell functions.

KEY FINDINGS

PDGF-BB stimulation initiated autophagy activation and synthetic phenotype transition by decreasing α-smooth muscle-actin (SMA), calponin and myosin heavy chain (MHC) and increasing osteopontin (OPN) expression. However, U0126, a potent extracellular signal-regulated kinase 1/2 (Erk1/2) inhibitor, decreased PDGF-BB-induced LC3 expression, while rapamycin, an inhibitor of the mammalian target of rapamycin (mTOR), increased it. Furthermore, U0126 decreased the expresseion of autophagy-related genes (Atgs) such as beclin-1, Atg7, Atg5, and Atg12-Atg5 complex, indicating that Erk1/2 is a regulator of PDGF-BB-induced VSMC autophagy. Regardless of autophagy inhibition by U0126 or activation by rapamycin, the PDGF-BB-induced decrease in SMA, calponin and MHC and increase in OPN expression were inhibited. Furthermore, PDGF-BB-stimulated VSMC proliferation, migration and proliferating cell nuclear antigen (PCNA) expression were inhibited by U0126 and rapamycin.

SIGNIFICANCE

These findings suggest that PDGF-BB-induced autophagy is strongly regulated by Erk1/2, an mTOR-independent pathway, and any approach for targeting autophagy modulation is a potential therapeutic strategy for addressing abnormal VSMC proliferation and migration.

Role of Uremic Toxins in Early Vascular Ageing and Calcification

In patients with advanced chronic kidney disease (CKD), the accumulation of uremic toxins, caused by a combination of decreased excretion secondary to reduced kidney function and increased generation secondary to aberrant expression of metabolite genes, interferes with different biological functions of cells and organs, contributing to a state of chronic inflammation and other adverse biologic effects that may cause tissue damage. Several uremic toxins have been implicated in severe vascular smooth muscle cells (VSMCs) changes and other alterations leading to vascular calcification (VC) and early vascular ageing (EVA). The above mentioned are predominant clinical features of patients with CKD, contributing to their exceptionally high cardiovascular mortality. Herein, we present an update on pathophysiological processes and mediators underlying VC and EVA induced by uremic toxins. Moreover, we discuss their clinical impact, and possible therapeutic targets aiming at preventing or ameliorating the harmful effects of uremic toxins on the vasculature.

Health benefits of sesamin on cardiovascular disease and its associated risk factors

Sesamin, a major lignin isolated from sesame (Sesamum indicum) seeds and sesame oil, is known to possess antioxidant and anti-inflammatory properties. Several studies have revealed that oxidative stress and inflammation play a major role in a variety of cardiovascular diseases (CVDs). This comprehensive review summarizes the evidence on the effects of sesamin on CVD and its risk factors, principally due to its antioxidant properties. Specifically, this review highlights the mechanisms underlying the anti-hypertensive, anti-atherogenic, anti-thrombotic, anti-diabetic, and anti-obesity, lipolytic effects of sesamin both in vivo and in vitro, and identifies the signaling pathways targeted by sesamin and its metabolites. The data indicates that RAS/MAPK, PI3K/AKT, ERK1/2, p38, p53, IL-6, TNFα, and NF-κB signaling networks are all involved in moderating the various effects of sesamin on CVD and its risk factors. In conclusion, the experimental evidence suggesting that sesamin can reduce CVD risk is convincing. Thus, sesamin can be potentially useful as an adjuvant therapeutic agent to combat CVD and its multitude of risk factors.

Ursodeoxycholic acid inhibits intimal hyperplasia, vascular smooth muscle cell excessive proliferation, migration via blocking miR-21/PTEN/AKT/mTOR signaling pathway

Excessive migration and proliferation of vascular smooth muscle cells (VSMCs) are critical cellular events that lead to intimal hyperplasia in atherosclerosis and restenosis. In this study, we investigated the protective effects of ursodeoxycholic acid (UDCA) on intimal hyperplasia and VSMC proliferation and migration, and the underlying mechanisms by which these events occur. A rat unilateral carotid artery was ligated to induce vascular injury and the microRNA (miRNA) expression profiles were determined using miRNA microarray analysis. We observed that UDCA significantly reduced the degree of intimal hyperplasia and induced miR-21 dysregulation. Restoration of miR-21 by agomir-miR-21 reversed the protective effects of UDCA on intimal hyperplasia and proliferation in vivo. In vitro, UDCA suppressed PDGF-BB-induced VSMC proliferation, invasion and migration in a dose-dependent manner, whereas the suppressive effect of UDCA was abrogated by overexpression of miR-21 in PDGF-BB-incubated VSMCs. Furthermore, we identified that miR-21 in VSMCs targeted the phosphatase and tensin homolog (PTEN), a tumor suppressor gene, negatively modulated the AKT/mTOR pathway. More importantly, we observed that that UDCA suppressed AKT/mTOR signaling pathway in the carotid artery injury model, whereas this pathway was reactivated by overexpression of miR-21. Taken together, our findings indicated that UDCA inhibited intimal hyperplasia and VSMCs excessive migration and proliferation via blocking miR-21/PTEN/AKT/mTOR signaling pathway, which suggests that UDCA may be a promising candidate for the therapy of atherosclerosis.

MicroRNA-221 is overexpressed in the equine asthmatic airway smooth muscle and modulates smooth muscle cell proliferation

Airway wall remodeling, including hyperplasia and hypertrophy of smooth muscle (ASM) cells leading to an increased smooth muscle mass, is considered central to asthma. However, molecular pathways responsible for ASM remodeling remain poorly understood. MicroRNAs (miRNAs) have emerged as key regulators of inflammatory and repair processes affecting the lungs and can downregulate protein expression by inhibiting target mRNA translation. We therefore hypothesized that miRNAs are involved in ASM remodeling in asthma by modulating ASM proliferation. We have analyzed the expression of miRNAs in bronchial smooth muscle from asthmatic horses during disease exacerbation and remission and from controls. Their involvement in ASM cell proliferation was then studied. Our results shown that miR-26a, miR-133, and miR-221 were upregulated in ASM from horses with asthma exacerbation compared with asthma remission and controls. MiR-221 induced cell hyperproliferation and reduced the expression of contractile gene markers in ASM cells. These changes were associated with the decreased mRNA expression of cell cycle regulatory genes (p53, p21, and p27). In conclusion, we demonstrated for the first time an upregulation of miR-221 in asthmatic airway smooth muscle and confirm the involvement of miR-221 in ASM cell proliferation by regulation of the cell cycle arrest genes. Targeting miR-221 network genes may represent a novel approach for the treatment of ASM remodeling in asthma.

MicroRNA-451 inhibits vascular smooth muscle cell migration and intimal hyperplasia after vascular injury via Ywhaz/p38 MAPK pathway

Increasing evidence has indicated that intimal hyperplasia is a common event in the pathophysiology of many vascular diseases including atherosclerosis (AS). Recently, deregulated microRNAs (miRNAs) have been reported to be associated with the pathophysiology of AS. However, the biological function and regulatory mechanisms of miRNAs in intimal hyperplasia in AS remain largely unclear. The aim of this study was to investigate the effects of miRNAs on intimal hyperplasia and reveal the underlying mechanisms of their effects. Firstly, the model of rat vascular injury was successfully constructed in vivo. Then, the miRNAs expression profiles were analyzed by miRNA microarray. It was observed that miR-451 was significantly downregulated in injury carotid arteries. Subsequently, we investigated miR-451 function and found that upregulation of miR-451 by agomir-451 improves intimal thickening in rats following vascular injury. It was also observed that miR-451 was downregulated in the VSMCs following platelet-derived growth factor type BB (PDGF-BB) stimulation. The upregulation of miR-451 attenuated PDGF-BB-induced VSMCs injury, as evidenced by inhibition of proliferation, invasion and migration. Besides, overexpression of miR-451 blocked the activation of p38 MAPK signaling pathway in PDGF-BB treated VSMCs, as demonstrated by the downregulation of phosphorylated (p-) p38. In addition, Ywhaz, a positive regulator of p38 MAPK signaling pathway, was found to be a direct target of miR-451 in the VSMCs and this was validated using a luciferase reporter assay. Overexpression of Ywhaz partially abolished the inhibitory effects of miR-451 overexpression on PDGF-BB induced VSMCs injury. Collectively, these findings indicated that miR-451 protected intimal hyperplasia and PDGF-BB-induced VSMCs injury by Ywhaz/p38 MAPK pathway, and miR-451 may be considered as a potential therapeutic target in the treatment of AS.

Computer-aided drug design and inhibitive effect of a novel nitrogenous heterocyclic compound and its mechanism on glioma U251 cells and breast cancer MCF-7 cells

Background

Glioma and breast cancer are severe malignant cancerous tumors that highlight the importance of developing new anti-cancer drugs. The aim of this study was to explore the effects of a novel nitrogenous heterocyclic compound on glioma and breast cancer cells and to determine its mechanism of action.

Methods

We designed and synthesized a novel nitrogenous heterocyclic compound, 3-(4-amino-1H-benzo[d]imidazole-2-carboxamido)-4-oxo-3,4-dihydroimidazo[5,1-d][1,2,3,5] tetrazine-8-carboxamide, based on alkylglycerone phosphate synthase (AGPS) using computer-aided drug design (CADD), and we measured its effect on the proliferation, invasion, cell cycle and apoptosis of U251 glioma and MCF-7 breast cancer cells. In addition, the compound’s effect on the expression of tumor-related mRNA, circular RNAs (circRNAs) and long non-coding RNAs (lncRNAs) was explored.

Results

It was found that the nitrogenous heterocyclic compound could induce cell cycle arrest at the G2/M phase of U251/MCF-7 cells and activate apoptosis. Real-time PCR showed that the expression levels of tumor-related mRNA, circRNAs and lncRNAs were impacted.

Conclusion

We concluded that the nitrogenous heterocyclic compound inhibits the proliferation and invasion of U251 glioma and MCF-7 breast cancer cells through the induction of apoptosis and cell cycle arrest by regulating tumor-related genes.

Vascular smooth muscle cell proliferation as a therapeutic target. Part 2: Natural products inhibiting proliferation

Many natural products have been so far tested regarding their potency to inhibit vascular smooth muscle cell proliferation, a process involved in atherosclerosis, pulmonary hypertension and restenosis. Compounds studied in vitro and in vivo as VSMC proliferation inhibitors include, for example indirubin-3'-monoxime, resveratrol, hyperoside, plumericin, pelargonidin, zerumbone and apamin. Moreover, taxol and rapamycin, the most prominent compounds applied in drug-eluting stents to counteract restenosis, are natural products. Numerous studies show that natural products have proven to yield effective inhibitors of vascular smooth muscle cell proliferation and ongoing research effort might result in the discovery of further clinically relevant compounds.

Chicoric acid prevents PDGF-BB-induced VSMC dedifferentiation, proliferation and migration by suppressing ROS/NFκB/mTOR/P70S6K signaling cascade

Phenotypic switch of vascular smooth muscle cells (VSMCs) is characterized by increased expressions of VSMC synthetic markers and decreased levels of VSMC contractile markers, which is an important step for VSMC proliferation and migration during the development and progression of cardiovascular diseases including atherosclerosis. Chicoric acid (CA) is identified to exert powerful cardiovascular protective effects. However, little is known about the effects of CA on VSMC biology. Herein, in cultured VSMCs, we showed that pretreatment with CA dose-dependently suppressed platelet-derived growth factor type BB (PDGF-BB)-induced VSMC phenotypic alteration, proliferation and migration. Mechanistically, PDGF-BB-treated VSMCs exhibited higher mammalian target of rapamycin (mTOR) and P70S6K phosphorylation, which was attenuated by CA pretreatment, diphenyleneiodonium chloride (DPI), reactive oxygen species (ROS) scavenger N-acetyl-l-cysteine (NAC) and nuclear factor-κB (NFκB) inhibitor Bay117082. PDGF-BB-triggered ROS production and p65-NFκB activation were inhibited by CA. In addition, both NAC and DPI abolished PDGF-BB-evoked p65-NFκB nuclear translocation, phosphorylation and degradation of Inhibitor κBα (IκBα). Of note, blockade of ROS/NFκB/mTOR/P70S6K signaling cascade prevented PDGF-BB-evoked VSMC phenotypic transformation, proliferation and migration. CA treatment prevented intimal hyperplasia and vascular remodeling in rat models of carotid artery ligation in vivo. These results suggest that CA impedes PDGF-BB-induced VSMC phenotypic switching, proliferation, migration and neointima formation via inhibition of ROS/NFκB/mTOR/P70S6K signaling cascade.

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Chicoric acid attenuated PDGF-BB-evoked VSMC phenotypic transformation, proliferation and migration.

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Chicoric acid antagonized the activated ROS/NFκB/mTOR/P70S6K signaling pathway in VSMCs.

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Chicoric acid treatment prevented intimal hyperplasia in rat models of carotid artery ligation.

Rubiarbonone C inhibits platelet-derived growth factor-induced proliferation and migration of vascular smooth muscle cells through the focal adhesion kinase, MAPK and STAT3 Tyr705 signalling pathways

BACKGROUND AND PURPOSE

The proliferation and migration of vascular smooth muscle cells (VSMCs) induced by platelet-derived growth factor (PDGF) are important steps in cardiovascular diseases, including neointimal lesion formation, myocardial infarction and atherosclerosis. Here, we evaluated the rubiarbonone C-mediated signalling pathways that regulate PDGF-induced VSMC proliferation and migration.

EXPERIMENTAL APPROACH

Cell proliferation and migration were measured in cells treated with rubiarbonone C followed by PDGF BB using the MTT assay, [³ H]-thymidine incorporation, flow cytometry and wound-healing migration assay, MMP gelatin zymography, a fluorescence assay for F-actin. Western blotting of molecules including MAPK, focal adhesion kinase (FAK) and STAT3 and an immunofluorescence assay using anti-PCNA and -STAT3 antibodies were performed to evaluate rubiarbonone C signalling pathway(s). The medial thickness of the carotid artery was evaluated using a mouse carotid ligation model.

KEY RESULTS

Rubiarbonone C inhibited PDGF-induced VSMC proliferation and migration and diminished the ligation-induced increase in medial thickness of the carotid artery. In PDGF-stimulated VSMCs rubiarbonone C decreased the following: (i) levels of cyclin-dependent kinases, cyclins, PCNA and hyperphosphorylated retinoblastoma protein; (ii) levels and activity of MMP2 and MMP9; (iii) activation of MAPK; (iv) F-actin reorganization, by reducing FAK activation; (v) activation of STAT3.

CONCLUSIONS AND IMPLICATIONS

These findings suggest that rubiarbonone C inhibits the proliferation and migration of VSMCs by inhibiting the FAK, MAPK and STAT3 signalling pathways. Therefore, rubiarbonone C could be a good candidate for the treatment of cardiovascular disease.

Inhibition of Collagen-Induced Platelet Aggregation by the Secobutanolide Secolincomolide A from Lindera obtusiloba Blume

Atherothrombosis is one of the main underlying cause of cardiovascular diseases. In addition to treating atherothrombosis with antithrombotic agents, there is growing interest in the role of natural food products and biologically active ingredients for the prevention and treatment of cardiovascular diseases. This study aimed to investigate the effect of secolincomolide A (3) isolated from Lindera obtusiloba Blume on platelet activity and identify possible signaling pathways. In our study, the antiplatelet activities of 3 were measured by collagen-induced platelet aggregation and serotonin secretion in freshly isolated rabbit platelets. Interestingly, 3 effectively inhibited the collagen-induced platelet aggregation and serotonin secretion via decreased production of diacylglycerol, arachidonic acid, and cyclooxygenase-mediated metabolites such as thromboxane B₂ (TXB₂), and prostaglandin D₂ (PGD₂). In accordance with the antiplatelet activities, 3 prolonged bleeding time and attenuated FeCl₃-induced thrombus formation in arterial thrombosis model. Notably, 3 abolished the phosphorylation of phospholipase Cγ2 (PLCγ2), spleen tyrosine kinase (Syk), p47, extracellular signal-regulated kinase 1/2 (ERK1/2), protein kinase B (Akt) by inhibiting the activation of the collagen receptor, glycoprotein VI (GPVI). Taken together, our results indicate the therapeutic potential of 3 in antiplatelet action through inhibition of the GPVI-mediated signaling pathway and the COX-1-mediated AA metabolic pathways.

Adipose differentiation‑related protein knockdown inhibits vascular smooth muscle cell proliferation and migration and attenuates neointima formation

Vascular smooth muscle cells (VSMCs) have an important role in atherosclerosis development. Evidence has demonstrated that adipose differentiation-related protein (ADRP) is associated with foam cell formation and atherosclerosis progression. However, to the best of our knowledge, no previous studies have investigated the role of ADRP knockdown in platelet-derived growth factor (PDGF)-stimulated proliferation and migration of VSMCs in vitro. Furthermore, the effect of ADRP knockdown on neointima formation in vivo remains unclear. In the present study, primary human aortic VSMCs were incubated with PDGF following ADRP small interfering (si)RNA transfection. Cell viability, migration and cell cycle distribution were analyzed by MTT, wound healing and Transwell assays and flow cytometry, respectively. Extracellular signal-regulated kinase (ERK), phosphorylated (p)-ERK, Akt, p-Akt, proliferating cell nuclear antigen (PCNA), matrix metalloproteinase (MMP)-2 and MMP-9 protein levels were determined by western blotting. Apolipoprotein E^−/− mice fed an atherogenic diet were injected with siADRP or control siRNA twice a week. After 3 weeks of therapy, aortas were excised and ADRP mRNA and protein expression was determined. Neointima formation was assessed by hematoxylin and eosin staining. The results of the current study demonstrated that ADRP knockdown significantly inhibited PDGF-induced increases in VSMC viability, caused G1 phase cell cycle arrest and decreased PCNA expression. Knockdown of ADRP inhibited PDGF-induced migration of VSMCs by reducing MMP protein expression and activity. In addition, the present study also demonstrated that ADRP knockdown inhibited ERK and Akt signaling pathways in response to PDGF. Furthermore, siADRP administration suppressed neointima formation in the mouse model. The results of the present study indicate that ADRP may be a potential target for the treatment of atherosclerosis.

Wedelolactone, a plant coumarin, prevents vascular smooth muscle cell proliferation and injury-induced neointimal hyperplasia through Akt and AMPK signaling

Wedelolactone (WDL) is a natural compound derived from Chinese herbal medicine Eclipta prostrate L, and has been reported to exhibit various effects potentially beneficial for human health. However, the possible preventive effects of WDL toward vascular remodeling and mechanisms involved have not been investigated to date. In this study, we investigated the effects of WDL on proliferation induced by platelet-derived growth factor (PDGF) in primary rat aortic smooth muscle cells (VSMCs) and on neointimal hyperplasia resulted from balloon injury in rats. WDL exhibited strong inhibitory effects against PDGF-induced VSMC proliferation. Cell cycle analysis revealed that WDL induced G0/G1 arrest and prevented cell cycle from entering S phase. Immunoblot analysis suggested that the cell cycle arrest induced by WDL was through Akt suppression and adenosine 5'-monophosphate-activated protein kinase (AMPK) activation, with a subsequent cyclin-dependent kinase inhibitor p21 induction and cyclin D1 inhibition. We also observed that WDL notably reduced neointima-to-media area ratio of balloon-injured rat common carotid arteries (CCAs) in comparison with those untreated balloon-injured CCAs. The regulation of WDL on protein expressions of Akt, AMPK and cyclin D1 in vivo were also consistent with that in vitro. Taken together, our results suggest WDL exhibits potential preventive effects toward vascular remodeling and neointimal hyperplasia through the reduction of VSMC proliferation via inhibition of Akt and activation of AMPK.

FoxR2 promotes glioma proliferation by suppression of the p27 pathway

FoxR2 plays an important role in the development of many human tumors. However, the effects of FoxR2 on tumorigenicity of human glioma remain unclear. In this study, we investigated the roles of FoxR2 in cell proliferation and invasion of glioma. We found that overexpression of FoxR2 promoted the proliferation, migration and invasion of glioma cells. Knockout of FoxR2 induced G1 arrest by decreasing the expression levels of cyclin D1, cyclin E and p-Rb. Mechanistically, upregulation of FoxR2 increased the level and activity of MMP-2 and decreased the expression of p27. Furthermore, overexpression of FoxR2 decreased the nuclear accumulation of p27. Taken together, these results indicate that upregulation of FoxR2 may confer enhanced tumorigenicity in glioma cells.

Effects and Mechanism of Imatinib in Inhibiting Colon Cancer Cell Proliferation

Background

This study investigated the effects and mechanism of imatinib in inhibiting colon cancer cell proliferation.

Material/Methods

The SW480 cells were divided into 4 imatinib-treated groups: 0 μM, 1.25 μM, 2.5 μM, and 5μM. We analyzed the apoptosis and cell cycle of the 4 groups. The gene and protein expressions of p21, p27, HGF, and GAPDH were measured by RT-PCR and Western blot.

Results

Compared with the 0-μM imatinib-treated group, the apoptosis of 1.25-μM, 2.5-μM, and 5.0-μM treated groups was significantly induced (P<0.05, all). The G1 phase was significantly up-regulated in the 1.25-μM, 2.5-μM, and 5.0-μM treated groups compared with the 0-μM imatinib-treated group (P<0.05, respectively), but the S and G2 phase of 3 imatinib-treated groups were significantly down-regulated (P<0.05, all). The gene and protein expressions of p27 and HGF were significantly different among the 4 groups (P<0.05, all).

Conclusions

Imatinib inhibits proliferation of colon cancer cells by reducing HGF and increasing p27 in a dose-dependent manner.

Arborinane Triterpenoids from Rubia philippinensis Inhibit Proliferation and Migration of Vascular Smooth Muscle Cells Induced by the Platelet-Derived Growth Factor

The abnormal proliferation and migration of vascular smooth muscle cells (VSMCs) are associated with cardiovascular diseases and related complications. Such deleterious proliferation and migration events are triggered by cytokines and growth factors, and among them, platelet-derived growth factor (PDGF) is recognized as the most potent inducer. Despite the genus Rubia being researched to identify valuable commercial and medicinal virtues, Rubia philippinensis has rarely been investigated. Nine arborinane-type triterpenoids (1-9) were identified from this underutilized plant species. In particular, 4 was identified as the first arborinane derivative carrying a ketocarbonyl motif at C-19. The presence of the cyclopentanone moiety and the associated configurational assignment were determined by utilizing NOE and coupling constant analysis. These compounds were assessed for their inhibitory potential on PDGF-induced proliferation and the migration of VSMCs. Treatment with 5 μM compound 5 (62.6 ± 10.7%) and compound 9 (41.1 ± 4.7%) impeded PDGF-stimulated proliferation without exerting cytotoxicity. Compound 7 exhibited antimigration activity in a dose-dependent manner (38.5 ± 3.0% at 10 μM, 57.6 ± 3.2% at 30 μM). These results suggest that the arborinane-type triterpenoids may be a pertinent starting point for the development of cardiovascular drugs capable of preventing the intimal accumulation of VSMCs.