Thrombin stimulates VSMC proliferation through an EGFR-dependent pathway: involvement of MMP-2

Multistep Approach Points to Compounds Responsible for the Biological Activity and Safety of Hydrolates from Nine Lamiaceae Medicinal Plants on Human Skin Fibroblasts

As byproducts of essential oil distillation, hydrolates are used in natural cosmetics/biomedicine due to their beneficial skin effects. However, data on their safety with relevant biological targets, such as human skin cells, are scarce. Therefore, we have tested nine hydrolates from the Lamiaceae family with skin fibroblasts that are responsible for extracellular collagenous matrix builds. Thyme, oregano, and winter savoury hydrolates showed several times higher total phenolics, which correlated strongly with their radical scavenging and antioxidative capacity; there was no correlation between their viability profiles and the reducing sugar levels. No proteins/peptides were detected. All hydrolates appeared safe for prolonged skin exposure except for 10-fold diluted lavender, which showed cytotoxicity (~20%), as well as rosemary and lavandin (~10%) using viability, DNA synthesis, and cell count testing. Clary sage, oregano, lemon balm, and thyme hydrolates (10-fold diluted) increased fibroblast viability and/or proliferation by 10-30% compared with the control, while their viability remained unaffected by Mentha and winter savoury. In line with the STITCH database, increased viability could be attributed to thymol presence in oregano and thyme hydrolates in lemon balm, which is most likely attributable to neral and geranial. The proliferative effect of clary sage could be supported by alpha-terpineol, not linalool. The major volatile organic compounds (VOCs) associated with cytotoxic effects on fibroblasts were borneol, 1,8-cineole, and terpinene-4-ol. Further research with pure compounds is warranted to confirm the roles of VOCs in the observed effects that are relevant to cosmetic and wound healing aspects.

The Compatibility of Alisma and Atractylodes Affects the Biological Behaviours of VSMCs by Inhibiting the miR-128-5p/p21 Gene

Objective

The compatibility of Alisma and Atractylodes (AA) has been estimated to exhibit antiatherosclerotic effects, but the mechanism remains unclear. This study aimed to identify the role of AA in oxidized low-density lipoprotein (ox-LDL)-induced vascular smooth muscle cell (VSMC) behaviours and to explore the effects of microRNAs (miRNAs).

Methods

A scratch wound-healing assay was used to detect the migration of VSMCs, and immunocytochemistry and western blotting for SM22ɑ were used to evaluate phenotypic transformation. Bromodeoxyuridine (BrdU) immunocytochemistry and flow cytometry were applied to detect the proliferation of VSMCs. miRNA microarray profiling was performed using Lianchuan biological small RNA sequencing analysis. VSMCs were transfected with the miR-128-5p mimic and inhibitor, and the migration, phenotypic modulation, and proliferation of VSMCs were investigated. The 3'UTR-binding sequence site of miR-128-5p on the p21 gene was predicted and assessed by luciferase assays.

Result

AA and the extracellular regulated protein kinase 1/2 (ERK1/2) blocker U0126 markedly inhibited migration, elevated smooth muscle 22α (SM22α) expression, repressed VSMC proliferation, elevated miR-466f-3p and miR-425-3p expression, and suppressed miR-27a-5p and miR-128-5p expression in ox-LDL-induced VSMCs. miR-128-5p targets the tissue inhibitor of metalloproteinases (TIMPs), silent information regulator 2 (SIRT2), peroxisome proliferator-activated receptor (PPAR), and p21 genes, which are linked to the behaviours of VSMCs. The miR-128-5p mimic promoted the migration and proliferation of VSMCs and suppressed p21, p27, and SM22ɑ expression. The inhibitor increased p21, p27, and SM22ɑ expression and repressed the migration, phenotypic transformation, and proliferation of VSMCs. miR-128-5p directly targeted the 3'UTR-binding sequences of the p21 gene, negatively regulated p21 expression, and supported the proliferation of VSMCs.

Conclusion

Our research showed that the migration, phenotypic transformation, and proliferation of ox-LDL-induced VSMCs were repressed by AA through inhibiting miR-128-5p by targeting the p21 gene, which may provide an effective option for the treatment of atherosclerosis.

[The role of thrombin in the pathogenesis of atherosclerosis and its complications]

Thrombin is a key regulator of the homeostasis system. Also, it actively participates in progression of various systemic diseases, including atherosclerosis. There is a large amount of experimental and clinical data on the involvement of thrombin in the pathogenesis of ischemic heart disease (IHD). Thus, studying thrombin activity regulation is promising. Also, the question whether it is possible to use biomarkers of thrombin activity as predictors of cardiovascular complications in IHD patients is relevant. The present review focuses on major mechanisms of thrombin functioning, its role in development and progression of atherosclerosis, and available tests for evaluation of thrombin functional activity. Major clinical studies are discussed that evaluated the efficacy of thrombin inhibitors and protease-activated receptor antagonists.

Unique Angiogenesis From Cardiac Arterioles During Pericardial Adhesion Formation

Objectives

The molecular mechanisms underlying post-operative pericardial adhesions remain poorly understood. We aimed to unveil the temporal molecular and cellular mechanisms underlying tissue dynamics during adhesion formation, including inflammation, angiogenesis, and fibrosis.

Methods and Results

We visualized cell-based tissue dynamics during pericardial adhesion using histological evaluations. To determine the molecular mechanism, RNA-seq was performed. Chemical inhibitors were administered to confirm the molecular mechanism underlying adhesion formation. A high degree of adhesion formation was observed during the stages in which collagen production was promoted. Histological analyses showed that arterioles excessively sprouted from pericardial tissues after the accumulation of neutrophils on the heart surface in mice as well as humans. The combination of RNA-seq and histological analyses revealed that hyperproliferative endothelial and smooth muscle cells with dedifferentiation appeared in cytokine-exposed sprouting vessels and adhesion tissue but not in quiescent vessels in the heart. SMAD2/3 and ERK activation was observed in sprouting vessels. The simultaneous abrogation of PI3K/ERK or TGF-β/MMP9 signaling significantly decreased angiogenic sprouting, followed by inhibition of adhesion formation. Depleting MMP9-positive neutrophils shortened mice survival and decreased angiogenic sprouting and fibrosis in the adhesion. Our data suggest that TGF-β/matrix metalloproteinase-dependent tissue remodeling and PI3K/ERK signaling activation might contribute to unique angiogenesis with dedifferentiation of vascular smooth muscle cells from the contractile to the synthetic phenotype for fibrosis in the pericardial cavity.

Conclusions

Our findings provide new insights in developing prevention strategies for pericardial adhesions by targeting the recruitment of vascular cells from heart tissues.

Baicalin Alleviates Thrombin-Induced Inflammation in Vascular Smooth Muscle Cells

Atherosclerosis (AS) is a chronic inflammatory disease of the arterial intima. As AS represents the most common type of vascular disease, it affects millions of individuals and is a source of high morbidity and mortality rates worldwide. Overwhelming evidence indicates that AS-related inflammation is mediated by proinflammatory cytokines, chemokines, adhesion molecules and inflammatory signaling pathways, with each of these factors being shown to play critical roles during the entire progression of AS. While a number of drugs have been approved for use in the treatment of AS, their benefits are modest, which underscores the urgency for the development of new drug therapies. In part, these deficits in effective drugs can be attributable to the lack of a clear understanding of the molecular mechanisms of AS. In this study, we investigate the capacity for thrombin to trigger inflammation and induce cell proliferation in vascular smooth muscle cells (VSMCs). We then assessed the effects of baicalin and its potential mechanisms on VSMC inflammation as induced by thrombin. Baicalin, which is a natural bioactive compound of S. baicalensis Georgi (SBG), exerted a protective effect against thrombin-induced VSMC inflammation as resulting from the upregulation of PAR-1. This protection as exerted by baicalin appears to reside in its capacity to produce an inhibitory effect on the thrombin-induced activation of the ERK1/2 pathway. These findings suggest that baicalin may be a promising candidate for the treatment of atherosclerosis.

Matrix Metalloproteinases and Arterial Hypertension: Role of Oxidative Stress and Nitric Oxide in Vascular Functional and Structural Alterations

Various pathophysiological mechanisms have been implicated in hypertension, but those resulting in vascular dysfunction and remodeling are critical and may help to identify critical pharmacological targets. This mini-review article focuses on central mechanisms contributing to the vascular dysfunction and remodeling of hypertension, increased oxidative stress and impaired nitric oxide (NO) bioavailability, which enhance vascular matrix metalloproteinase (MMP) activity. The relationship between NO, MMP and oxidative stress culminating in the vascular alterations of hypertension is examined. While the alterations of hypertension are not fully attributable to these pathophysiological mechanisms, there is strong evidence that such mechanisms play critical roles in increasing vascular MMP expression and activity, thus resulting in abnormal degradation of extracellular matrix components, receptors, peptides, and intracellular proteins involved in the regulation of vascular function and structure. Imbalanced vascular MMP activity promotes vasoconstriction and impairs vasodilation, stimulating vascular smooth muscle cells (VSMC) to switch from contractile to synthetic phenotypes, thus facilitating cell growth or migration, which is associated with the deposition of extracellular matrix components. Finally, the protective effects of MMP inhibitors, antioxidants and drugs that enhance vascular NO activity are briefly discussed. Newly emerging therapies that address these essential mechanisms may offer significant advantages to prevent vascular remodeling in hypertensive patients.

miR-30b-5p Downregulation as a Predictive Biomarker of Coronary In-Stent Restenosis

In-stent restenosis (ISR) is one of the main limitations of percutaneous coronary intervention (PCI) therapy with drug-eluting stents (DES) implantation. The aim of this study was to determine if circulating microRNAs (miRNAs) have diagnostic capability for determining ISR in a cohort of matched patients. Blood samples were collected from 55 patients who underwent previously PCI and were readmitted for a new coronary angiography. Patients were divided into subgroups comprising patients who presented ISR or not (non-ISR). A microarray analysis determined that up to 49 miRNAs were differentially expressed between ISR and non-ISR patients. Of these, 10 miRNAs are related to vascular smooth muscle and endothelial cells proliferation, migration, and differentiation, well-known hallmarks of vascular remodeling. Additionally, we identified that the expression of miR-30b-5p is significantly lower in serum samples of ISR patients, as compared to non-ISR. A further analysis demonstrated that miR-30b-5p provides better values of the receiver operator characteristic curve than other miRNAs and biochemical parameters. Finally, the in-silico analysis suggests that miR-30b-5p is predicted to target 62 genes involved in different signaling pathways involved in vascular remodeling. In conclusion, we determined for the first time that circulating mi-R30b-5p can reliably prognose restenosis in patient with implanted DES, which could be potentially helpful in the establishment of an early diagnosis and therapy of ISR.

OCT4 regulated neointimal formation in injured mouse arteries by matrix metalloproteinase 2-mediated smooth muscle cells proliferation and migration

The excessive proliferation and migration of vascular smooth muscle cells (VSMCs) play vital roles in neointimal hyperplasia and vascular restenosis. In the present study, we aimed to investigate the function and mechanism of octamer-binding transcription factor 4 (OCT4, a key transcription factor for maintaining stem cells in de-differentiated state) on neointima formation in response to vascular injury. Quantitative reverse-transcription polymerase chain reaction and western blot results displayed a significant increase of OCT4 levels in injured carotid arteries. Immunohistochemistry and immunofluorescence assays confirmed that the increased OCT4 expression was primarily localized in α-SMA-positive VSMCs from neointima, and colocalized with PCNA in the nuclei of VSMCs. Adenovirus-mediated OCT4 overexpression in injured carotid arteries exacerbated intimal thickening, while OCT4 knockdown significantly inhibited intimal thickening. In-vitro experiments confirmed that the increased OCT4 expression in VMSCs could be induced by platelet-derived growth factor-BB (PDGF-BB) in a time-dependent manner. Overexpression of OCT4 greatly promoted VSMCs proliferation and migration, while OCT4 knockdown significantly retarded the PDGF-BB-induced excessive proliferation and migration of VSMCs. Bioinformatics analysis, dual-luciferase reporter assay, and chromatin immunoprecipitation assay confirmed that OCT4 could upregulate matrix metalloproteinases 2 (MMP2) expression through promoting its transcription. Moreover, knockdown of MMP2 significantly attenuated OCT4-mediated VSMCs proliferation and migration. These results indicated that OCT4 facilitated neointimal formation in response to vascular injury by MMP2-mediated VSMCs proliferation and migration, and targeting OCT4 in VSMCs might be a novel therapeutic strategy for vascular restenosis.

Proliferation of Vascular Smooth Muscle Cells under ox-LDL Is Regulated by Alismatis rhizoma Decoction via InhibitingERK1/2 and miR-17∼92a Cluster Activation

Context: Alismatis rhizome decoction (AD) exhibits antiatherosclerotic activities. The activity of AD against vascular smooth muscle cell (VSMC) proliferation remains unclear. Objective. The mechanisms and effects of AD on oxidized low-density lipoprotein (ox-LDL)-induced VSMC proliferation were explored. Materials and methods. The male SD rats were fed with AD (2.56 g/mL) or 0.9% NaCl by oral gavage 4 mL twice daily for 7 d. Then, AD-containing serum (ADcs) was collected. MTS assay was applied to measure the VSMC viability. The proliferation of VSMCs was detected by 5-bromodeoxyuridine (BrdU) immunocytochemistry. The microRNA (miRNA) profiling was performed, and the target genes of miRNAs were searched from the TargetScan 7.2 database. The expressions of matrix metalloproteinases-2/9 (MMP-2/9), cyclin D1/E, cyclin-dependent kinase inhibitor 1B (p27), extracellular regulated protein kinases 1/2 (ERK1/2), and ERK1/2 phosphorylation were examined by western blotting or quantitative reverse transcription PCR. Results. The ox-LDL-induced miR-17-92a expression promoted VSMC proliferation. AD and the ERK1/2 inhibitor U0126 (10 μmol/L) inhibited VSMC proliferation and reduced the overexpression of miR-17∼92a. AD was found to inhibit phosphorylation of ERK1/2 and reduced the expression of MMP-2/9 in VSMCs. The expression of cyclin D1/E was suppressed, and p27 was elevated following treatment with AD as well as ERK1/2 inhibitor. According to the TargetScan 7.2 database, the target genes of miR-17∼92a act on tissue inhibitors of metalloproteinases (TIMPs)-MMPs, p27/21 cyclins, and peroxisome-proliferator-activated receptor α (PPARα) ATP-binding cassette transporter (ABC) A1/G1, which are involved in the process of atherosclerosis. Conclusions. AD inhibits ox-LDL-induced VSMC proliferation via inhibiting ERK1/2 and miR-17∼92a activation. The results provide the multitarget mechanisms for application of AD in the treatment of atherosclerosis. It would be helpful to the treatment of cardiovascular and cerebral diseases.

Long non-coding RNA LINC00299 knockdown inhibits ox-LDL-induced T/G HAVSMC injury by regulating miR-135a-5p/XBP1 axis in atherosclerosis

BACKGROUND

Atherosclerosis (AS) is a highly relevant social problem. Long noncoding RNA (lncRNA) long intergenic non-coding00299 (LINC00299) participates in the regulation of AS development. Therefore, this study was to explore the potential role and mechanism of LINC00299 in AS.

METHODS

Human aortic vascular smooth muscle cells (T/G HA-VSMCs) were treated with oxidized low-density lipoprotein (ox-LDL). Cell viability and migration were measured by 3-(4, 5-dimethyl-2-thiazolyl)-2, 5-diphenyl-2-H-tetrazolium bromide (MTT) and transwell assays, severally. The activities of SOD and MDA were detected by total superoxide dismutase assay kit and malondialdehyde assay kit. The protein levels of ki67, matrix metalloproteinase 9 (MMP9) and X-box binding protein 1 (XBP1) were detected by western blot assay. The expression levels of LINC00299, microRNA-135a-5p (miR-135a-5p) and XBP1 were detected by real-time quantitative polymerase chain reaction (RT-qPCR). The binding relationship between miR-135a-5p and LINC00299 or XBP1 was predicted by miRcode and Starbase3.0 then verified by the dual-luciferase reporter assay.

RESULTS

Ox-LDL induced cell viability, oxidative damage and migration of T/G HA-VSMCs. LINC00299 knockdown weakened ox-LDL-induced T/G HA-VSMCs injury. Mechanical analysis confirmed that LINC00299 improved XBP1 expression by interacting with miR-135a-5p. Furthermore, rescue assays showed that LINC00299 regulated ox-LDL-induced T/G HA-VSMCs injury through the miR-135a-5p/XBP1 axis.

CONCLUSIONS

Our studies revealed the regulatory function of LINC00299/miR-135a-5p/XBP1 axis in AS development, suggesting a potential therapeutic strategy for AS treatment.

Role of Extracellular Matrix in Pathophysiology of Patent Ductus Arteriosus: Emphasis on Vascular Remodeling

The ductus arteriosus (DA) is a shunt vessel between the aorta and the pulmonary artery during the fetal period that is essential for the normal development of the fetus. Complete closure usually occurs after birth but the vessel might remain open in certain infants, as patent ductus arteriosus (PDA), causing morbidity or mortality. The mechanism of DA closure is a complex process involving an orchestration of cell-matrix interaction between smooth muscle cells (SMC), endothelial cells, and extracellular matrix (ECM). ECM is defined as the noncellular component secreted by cells that consists of macromolecules such as elastin, collagens, proteoglycan, hyaluronan, and noncollagenous glycoproteins. In addition to its role as a physical scaffold, ECM mediates diverse signaling that is critical in development, maintenance, and repair in the cardiovascular system. In this review, we aim to outline the current understandings of ECM and its role in the pathophysiology of PDA, with emphasis on DA remodeling and highlight future outlooks. The molecular diversity and plasticity of ECM present a rich array of potential therapeutic targets for the management of PDA.

Salvia miltiorrhiza-derived miRNAs suppress vascular remodeling through regulating OTUD7B/KLF4/NMHC IIA axis

Objective: Abnormal proliferation and migration of vascular smooth muscle cells (VSMCs) are essential for vascular remodeling. Natural compounds with diterpene chinone or phenolic acid structure from Salvia miltiorrhiza, an eminent medicinal herb widely used to treat cardiovascular diseases in China, can effectively attenuate vascular remodeling induced by vascular injury. However, it remains unknown whether Salvia miltiorrhiza-derived miRNAs can protect VSMCs from injury by environmental stimuli. Here, we explored the role and underlying mechanisms of Salvia miltiorrhiza-derived Sal-miR-1 and 3 in the regulation of VSMC migration and monocyte adhesion to VSMCs induced by thrombin. Methods: A mouse model for intimal hyperplasia was established by the ligation of carotid artery and the injured carotid arteries were in situ-transfected with Sal-miR-1 and 3 using F-127 pluronic gel. The vascular protective effects of Sal-miR-1 and 3 were assessed via analysis of intimal hyperplasia with pathological morphology. VSMC migration and adhesion were analyzed by the wound healing, transwell membrane assays, and time-lapse imaging experiment. Using loss- and gain-of-function approaches, Sal-miR-1 and 3 regulation of OTUD7B/KLF4/NMHC IIA axis was investigated by using luciferase assay, co-immunoprecipitation, chromatin immunoprecipitation, western blotting, etc. Results:Salvia miltiorrhiza-derived Sal-miR-1 and 3 can enter the mouse body after intragastric administration, and significantly suppress intimal hyperplasia induced by carotid artery ligation. In cultured VSMCs, these two miRNAs inhibit thrombin-induced the migration of VSMCs and monocyte adhesion to VSMCs. Mechanistically, Sal-miR-1 and 3 abrogate OTUD7B upregulation by thrombin via binding to the different sites of the OTUD7B 3'UTR. Most importantly, OTUD7B downregulation by Sal-miR-1 and 3 attenuates KLF4 protein levels via decreasing its deubiquitylation, whereas decreased KLF4 relieves its repression of transcription of NMHC IIA gene and thus increases NMHC IIA expression levels. Further, increased NMHC IIA represses VSMC migration and monocyte adhesion to VSMCs via maintaining the contractile phenotype of VSMCs. Conclusions: Our studies not only found the novel bioactive components from Salvia miltiorrhiza but also clarified the molecular mechanism underlying Sal-miR-1 and 3 inhibition of VSMC migration and monocyte adhesion to VSMCs. These results add important knowledge to the pharmacological actions and bioactive components of Salvia miltiorrhiza. Sal-miR-1 and 3-regulated OTUD7B/KLF4/NMHC IIA axis may represent a therapeutic target for vascular remodeling.

COL6A1 knockdown suppresses cell proliferation and migration in human aortic vascular smooth muscle cells

Vascular smooth muscle cell (VSMC) migration is an important pathophysiological signature of neointimal hyperplasia. The aim of the present study was to investigate the effects of collagen type VI α1 chain (COL6A1) on VSMC migration. COL6A1 expression was silenced in platelet-derived growth factor (PDGF-BB)-stimulated VSMCs. Cell counting kit-8, wound healing and Transwell assays were used to measure cell viability, migration and invasion, respectively. Reverse transcription-quantitative PCR and western blot analysis were performed to analyze the expression of factors associated with metastasis. COL6A1 silencing attenuated PDGF-BB-induced increases in cell viability and invasive abilities of VSMCs, in addition to partially reversing the increased expression of fibronectin (FN), matrix metalloproteinase (MMP)-2 and MMP-9 induced by PDGF-BB stimulation. The silencing of COL6A also overturned PDGF-BB-induced reduction in tissue inhibitor of metalloproteinase 2 expression in VSMCs. PDGF-BB activated the AKT/mTOR pathway, which was also inhibited by COL6A1 knockdown. Taken together, these findings suggest that COL6A1 silencing inhibited VSMC viability and migration by inhibiting AKT/mTOR activation.

Mechanisms of PAR-1 mediated kinase receptor transactivation: Smad linker region phosphorylation

Protease activated receptors (PARs) transactivate both epidermal growth factor receptors (EGFR) and transforming growth factor (TGF)-β receptors (TGFBR1) in vascular smooth muscle leading to the increased expression of genes (CHST11 and CHSY1) which are rate limiting for the enzymes that mediate hyperelongation of glycosaminoglycan (GAG) chains on the lipid-binding proteoglycan, biglycan. This is an excellent model to investigate mechanisms of transactivation as the processes are biochemically distinct. EGFR transactivation is dependent on the classical matrix metalloprotease (MMP) based triple membrane bypass mechanism and TGFBR1 transactivation is dependent on Rho/ROCK signalling and integrins. We have shown that all kinase receptor signalling is targeted towards phosphorylation of the linker region of the transcription factor, Smad2. We investigated the mechanisms of thrombin mediated kinase receptor transactivation signalling using anti-phospho antibodies and Western blotting and gene expression by RT-PCR. Thrombin stimulation of phospho-Smad2 (Ser 245/250/255) and of phospho-Smad2(Thr220) via EGFR transactivation commences quickly and extends out to at least 4 h whereas transactivation via TGFBR1 is delayed for 120 min but also persists for at least 4 h. Signalling of thrombin stimulated Smad linker region phosphorylation is approximately equally inhibited by the MMP inhibitor, GM6001 and the ROCK inhibitor, Y27632, and similarly expression of CHST11 and CHSY1 is approximately equally inhibited by GM6001 and Y27632. The data establishes Smad linker region phosphorylation as a central target of all transactivation signalling of GAG gene expression and thus an upstream kinase may be a target to prevent all transactivation signalling and its pathophysiological consequences.

Exosome-Mediated Transfer of ACE (Angiotensin-Converting Enzyme) From Adventitial Fibroblasts of Spontaneously Hypertensive Rats Promotes Vascular Smooth Muscle Cell Migration

Migration of vascular smooth muscle cells (VSMCs) is pivotal for vascular remodeling in hypertension. Vascular adventitial fibroblasts (AFs) are important in the homeostasis of vascular structure. This study is designed to investigate the roles of AF exosomes (AFE) in VSMC migration and underling mechanism. Primary VSMCs and AFs were obtained from the aorta of spontaneously hypertensive rats (SHR) and Wistar-Kyoto (WKY) rats. VSMC migration was evaluated with Boyden chamber assay and wound healing assay. AFE from WKY rats and SHR were isolated and identified. AFE from SHR promoted but AFE from WKY rats had no significant effect on VSMC migration. The effects of AFE on VSMC migration were prevented by an exosome inhibitor GW4869, an AT₁R (Ang II [angiotensin II] type 1 receptor) antagonist losartan, or an inhibitor of ACE (angiotensin-converting enzyme) captopril. ACE contents and activity were much higher in AFE from SHR than those from WKY rats. There were no significant difference in Ang II and AT₁R mRNA and protein levels between AFE from SHR and AFE from WKY rats. AFE from SHR increased Ang II and ACE contents and ACE activity in VSMCs of WKY rats and SHR. The changes of Ang II contents and ACE activity were prevented by captopril. ACE knockdown in AFs reduced ACE contents and activity in AFE from SHR and inhibited AFE-induced migration of VSMCs of WKY rats and those of SHR. These results indicate that exosomes from AFs of SHR transfer ACE to VSMCs, which increases Ang II levels and activates AT₁R in VSMCs and thereby promotes VSMC migration.

Matrix metalloproteinase-2-induced epidermal growth factor receptor transactivation impairs redox balance in vascular smooth muscle cells and facilitates vascular contraction

Increased reactive oxygen species (ROS) formation may enhance matrix metalloproteinase (MMP)-2 activity and promote cardiovascular dysfunction. We show for the first time that MMP-2 is upstream of increased ROS formation and activates signaling mechanisms impairing redox balance. Incubation of vascular smooth muscle cells (VSMC) with recombinant MMP-2 increased ROS formation assessed with dihydroethidium (DHE) by flow cytometry. This effect was blocked by the antioxidant apocynin or by polyethylene glycol-catalase (PEG-catalase), and by MMP inhibitors (doxycycline or GM6001). Next, we showed in HEK293 cells that MMP-2 transactivates heparin-binding epidermal growth factor (HB-EGF) leading to EGF receptor (EGFR) activation and increased ROS concentrations. This effect was prevented by the EGFR kinase inhibitor Ag1478, and by phospholipase C (PLC) or protein kinase C (PKC) inhibitors (A778 or chelerythrine, respectively), confirming the involvement of EGFR pathway in MMP-2-induce responses. Next, we showed that intraluminal exposure of aortas to MMP-2 increased vascular MMP-2 levels detected by immunofluorescence and gelatinolytic activity (by in situ zimography) in association with increased ROS formation. This effect was inhibited by MMP inhibitors (phenanthroline or doxycycline) and by apocynin or PEG-catalase. MMP-2 also increased aortic contractility to phenylephrine and this effect was prevented by MMP inhibitor GM6001 and by apocynin or PEG-catalase, showing again that increased ROS formation mediates functional effects of MMP-2. These results show that MMP-2 activates the EGFR and triggers downstream signaling pathways increasing ROS formation and promoting vasoconstriction. These findings may have various implications for cardiovascular diseases.

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MMP-2 is activated by reactive oxygen species and promotes cardiovascular diseases.

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We show here that MMP-2 is upstream of reactive oxygen species formation.

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This effect involves epidermal growth factor receptor transactivation.

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MMP-2 impairs redox balance and contributes to vascular contraction.

Cinnamaldehyde protects VSMCs against ox-LDL-induced proliferation and migration through S arrest and inhibition of p38, JNK/MAPKs and NF-κB

Cinnamaldehyde (Cin), as a traditional flavor constituent isolated from the bark of Cinnamonum cassia Presl, has been commonly used for - digestive, cardiovascular and immune system diseases. The pathology of vascular smooth muscle cells (VSMCs) accelerated the progression of atherosclerosis. In our study, we found that cinnamaldehyde significantly suppressed ox-LDL-induced VSMCs proliferation, migration and inflammatory cytokine overproduction, as well as foam cell formation in VSMCs and macrophages. Moreover, cinnamaldehyde inhibited the phosphorylation of p38, JNK and p65 NF-κB and increased heme oxygenase-1 (HO-1) activity. In addition, cinnamaldehyde reduced monocyte chemotactic protein-1 (MCP-1), matrix metalloproteinase-2 (MMP-2) and lectin-like oxidized low density lipoprotein receptor-1 (LOX-1) expression. Furthermore, cinnamaldehyde arrested cell cycle in S phase. Thus, results indicated that cinnamaldehyde antagonized the ox-LDL-induced VSMCs proliferation, migration, inflammation and foam cell formation through regulation of HO-1, MMP-2, LOX-1 and blockage of cell cycle, and - suppression of p38, JNK/MAPK and NF-κB signaling pathways.

Modulation of binding to vascular endothelial growth factor and receptor by heparin derived oligosaccharide

We investigated the mechanism of heparin-derived oligosaccharide on the proliferation of vascular smooth muscle cell (VSMC) induced by vascular endothelial growth factor (VEGF). Expression levels of VEGFR 1 and VEGFR 2 were examined by RT-PCR, and the corresponding protein expression levels were detected by Western blotting and immunocytochemistry. Western blotting was taken to identify the expression levels of mechanism proteins. The binding of VEGF and VEGFR 2 was measured by co-IP. Besides, HS competition assay was to detect the ability of HDO to compete with Heparin for VEGF165. HDO showed an inhibitory effect on the expression of VEGFR1/2 proteins and PKC, MAPK, PI3K/Akt pathways. In addition, HDO affected the binding of VEGF-VEGFR, which may be one of the most important mechanisms of HDO suppress the cell proliferation induced by growth factors. Thus HDO showed the ability as a VEGF antagonist.

EGFR is a pivotal regulator of thrombin-mediated inflammation in primary human nucleus pulposus culture

We found that the coagulation and cytokine pathways were important mechanisms involve in the degeneration of intervertebral discs (IVD) using a microarray approach to analyze gene expression in different grades of specimens. Furthermore, using a cytokine/chemokine array, a significant increase in CXCL8 expression was observed in human nucleus pulposus (NP) cells after thrombin treatment. The enhancement of CXCL8 expression by thrombin was activated by the PAR1 receptor. Importantly, analysis of degenerated human NP tissue samples showed that EGFR expression positively correlated with the grade of tissue degeneration. In NP cells, thrombin caused an increase in phosphorylation of the EGFR at the Tyr1068, and treatment with the pharmacological EGFR inhibitor, AG1473 effectively blocked thrombin-enhanced CXCL8 production. Surprisingly, inhibition of STAT3 for 24 h decreased expression of EGFR. Treatment with thrombin also increased Akt and GSK3α/β activation; this activation was also blocked by EGFR inhibitor. Although c-Src, ERK, and FAK were activated by thrombin, only c-Src and ERK were involved in the STAT3/CXCL8 induction. Our findings indicate that stimulation of an inflammatory response in NP cells by thrombin is part of a specific pathophysiology that modulates the EGFR activation through activation of Src/ERK/STAT3 signaling.

RNA sequencing to determine the contribution of kinase receptor transactivation to G protein coupled receptor signalling in vascular smooth muscle cells

G protein coupled receptor (GPCR) signalling covers three major mechanisms. GPCR agonist engagement allows for the G proteins to bind to the receptor leading to a classical downstream signalling cascade. The second mechanism is via the utilization of the β-arrestin signalling molecule and thirdly via transactivation dependent signalling. GPCRs can transactivate protein tyrosine kinase receptors (PTKR) to activate respective downstream signalling intermediates. In the past decade GPCR transactivation dependent signalling was expanded to show transactivation of serine/threonine kinase receptors (S/TKR). Kinase receptor transactivation enormously broadens the GPCR signalling paradigm. This work utilizes next generation RNA-sequencing to study the contribution of transactivation dependent signalling to total protease activated receptor (PAR)-1 signalling. Transactivation, assessed as gene expression, accounted for 50 percent of the total genes regulated by thrombin acting through PAR-1 in human coronary artery smooth muscle cells. GPCR transactivation of PTKRs is approximately equally important as the transactivation of the S/TKR with 209 and 177 genes regulated respectively, via either signalling pathway. This work shows that genome wide studies can provide powerful insights into GPCR mediated signalling pathways.

Canstatin stimulates migration of rat cardiac fibroblasts via secretion of matrix metalloproteinase-2

Type IV collagen, a nonfibrillar type, is ubiquitously expressed in the basement membrane around cardiomyocytes. Canstatin, a cleaved product of α2 chain of type IV collagen, is an antiangiogenic factor. Because it has not been clarified whether canstatin exerts other biological activities in heart, we investigated the effects of canstatin on adult rat cardiac fibroblasts. Cell migration was determined by Boyden chamber assay. Western blotting was performed to detect secretion of matrix metalloproteinase-2 (MMP-2) and MMP-9 and phosphorylation of extracellular signal-regulated kinase (ERK). Localization of MMP-2 was detected by immunofluorescence staining. Canstatin (250 ng/ml) significantly increased migration, secretion, and activity of MMP-2 but not MMP-9. CTTHWGFTLC peptide, an MMP inhibitor and small interfering RNA (siRNA) against MMP-2 suppressed the canstatin-induced (250 ng/ml, 24 h) migration. Canstatin (250 ng/ml, 30 min) significantly increased phosphorylation of ERK. PD98059, a MEK inhibitor, significantly suppressed the canstatin-induced (250 ng/ml, 24 h) migration but not secretion of MMP-2. An increase in MMP-2 expression was observed in cytoplasm of the canstatin-treated (250 ng/ml) cardiac fibroblasts (within 30 min). Canstatin induced actin stress fiber formation, which was inhibited by Y-27632, a Rho-associated kinase inhibitor. Y-27632 also suppressed the canstatin-induced (250 ng/ml, 24 h) MMP-2 secretion. Canstatin (250 ng/ml, 30 min) failed to induce ERK phosphorylation in MMP-2 siRNA-treated cardiac fibroblasts. In conclusion, this study revealed a novel function of canstatin for inducing cell migration of adult rat cardiac fibroblasts at least in part by ERK phosphorylation through MMP-2 secretion, possibly via actin cytoskeletal change.

Wnt signaling contributes to vascular calcification by induction of matrix metalloproteinases

BACKGROUND

Vascular calcifications such as arteriosclerosis, which is characterized by a calcificiation of the tunica media, represent major comorbidities e.g. in patients with chronic kidney disease (CKD). An essential step during the development of arteriosclerosis is the transdifferentiation/calcification of vascular smooth muscle cells (VSMC) resembling osteogenesis. The matrix metalloproteinases (MMP)-2 and -9 were shown to promote these VSMC calcifications and their inhibition is of therapeutic value to prevent arteriosclerosis in preclinical studies. Aiming for an understanding of the underlying regulatory mechanisms of MMPs we here investigated, if the MMP-mediated VSMC calcification involves altered signaling of the Wnt pathway, which is known to impact osteogenesis.

METHODS

We used an experimental in vitro model of vascular calcification. Transdifferentiation/calcification of murine VSMC was induced by elevated calcium and phosphorus levels. Calcification was assessed by calcium and alkaline phosphatase measurements. Activation/activity of the gelatinases MMP-2 and MMP-9 was assessed by conversion of fluorescence-labelled substrates. Activation of the Wnt pathway was analysed by a reporter gene assay.

RESULTS

Besides pro-calcifying culture conditions, also activation of Wnt signaling by a specific agonist (under normal culture conditions) stimulated VSMC-calcification accompanied by enhanced expression and secretion of the gelatinases MMP-2 and -9. Vice versa, recombinant MMP-2 and -9 induced a time-delayed activation of Wnt signaling after 72 h in VSMC but showed no direct effects after 24-48 h. These effects were blocked by pharmacological inhibition of MMPs or of Wnt signaling.

CONCLUSIONS

Our study suggests that the pro-calcifying environment in CKD induces Wnt signaling in VSMC which in turn contributes to the induction of MMPs which then foster the development of arteriosclerosis. Thus, besides MMP inhibition, the inhibition of Wnt signaling in VSMC might represent a therapeutic target for the prevention of vascular calcifications.

Alpha1a-Adrenoceptor Genetic Variant Triggers Vascular Smooth Muscle Cell Hyperproliferation and Agonist Induced Hypertrophy via EGFR Transactivation Pathway

α_1a Adrenergic receptors (α_1aARs) are the predominant AR subtype in human vascular smooth muscle cells (SMCs). α_1aARs in resistance vessels are crucial in the control of blood pressure, yet the impact of naturally occurring human α_1aAR genetic variants in cardiovascular disorders remains poorly understood. To this end, we present novel findings demonstrating that 3D cultures of vascular SMCs expressing human α_1aAR-247R (247R) genetic variant demonstrate significantly increased SMC contractility compared with cells expressing the α_1aAR-WT (WT) receptor. Stable expression of 247R genetic variant also triggers MMP/EGFR-transactivation dependent serum- and agonist-independent (constitutive) hyperproliferation and agonist-dependent hypertrophy of SMCs. Agonist stimulation reduces contractility Using pathway-specific inhibitors we determined that the observed hyperproliferation of 247R-expressing cells is triggered via β-arrestin1/Src/MMP-2/EGFR/ERK-dependent mechanism. MMP-2-specific siRNA inhibited 247R-triggered hyperproliferation indicating MMP-2 involvement in 247R-triggered hyperproliferation in SMCs. β-arrestin1-specific shRNA also inhibited 247R-triggered hyperproliferation but did not affect hypertrophy in 247R-expressing SMCs, indicating that agonist-dependent hypertrophy is independent of β-arrestin1. Our data reveal that in different cardiovascular cells the same human receptor genetic variant can activate alternative modulators of the same signaling pathway. Thus, our findings in SMCs demonstrate that depending on the type of cells expressing the same receptor (or receptor variant), different target-specific inhibitors could be used to modulate aberrant hyperproliferative or hypertrophic pathways in order to restore normal phenotype.

Inhibitory effects of fermented extract of Ophiopogon japonicas on thrombin-induced vascular smooth muscle cells

Ophiopogon japonicus is known to have various pharmacological effects. The present study investigated the effects of an extract of fermented Ophiopogon japonicas (FEOJ) on thrombin‑treated vascular smooth muscle cells (VSMCs). FEOJ treatment inhibited the proliferation of VSMCs treated with thrombin as indicated by an MTT assay. These inhibitory effects were associated with decreased phosphorylation of AKT, reduced expression of cyclin D1 and increased expression of p27KIP1 in thrombin‑induced VSMCs. In addition, FEOJ treatment suppressed the thrombin‑stimulated migration of VSMCs as demonstrated by a wound‑healing migration assay. Furthermore, zymographic analyses demonstrated that treatment of FEOJ with VSMCs suppressed the thrombin‑induced expression of matrix metalloproteinase (MMP)‑2, which was attributed to the reduction of nuclear factor (NF)‑κB binding activity. Collectively, these results demonstrated that FEOJ induced p27KIP1 expression, reduced cyclin D1 expression and AKT phosphorylation, and inhibited MMP‑2 expression mediated by downregulation of NF‑κB binding activity in thrombin‑treated VSMCs, which led to growth inhibition and repression of migration. These results supported the use of FEOJ for the prevention of vascular diseases and provided novel insight into the underlying mechanism of action.

Salusin-β contributes to vascular remodeling associated with hypertension via promoting vascular smooth muscle cell proliferation and vascular fibrosis

Vascular smooth muscle cell (VSMC) proliferation and vascular fibrosis are closely linked with hypertension and atherosclerosis. Salusin-β is a bioactive peptide involved in the pathogenesis of atherosclerosis. However, it is still largely undefined whether salusin-β is a potential candidate in the VSMC proliferation and vascular fibrosis. Experiments were carried out in human vascular smooth muscle cells (VSMCs) and in rats with intravenous injection of lentivirus expressing salusin-β. In vitro, salusin-β promoted VSMCs proliferation, which was attenuated by adenylate cyclase inhibitor SQ22536, PKA inhibitor Rp-cAMP, epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor AG1478, ERK inhibitor U0126 or cAMP response element binding protein (CREB) inhibitor KG501. It promoted the phosphorylation of ERK1/2, CREB and EGFR, which were abolished by SQ22536 or Rp-cAMP. Furthermore, epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor AG1478 diminished the salusin-β-evoked ERK1/2 and CREB phosphorylation. On the other hand, salusin-β increased collagen-I, collagen-III, fibronectin and connective tissue growth factor (CTGF) mRNA and phosphorylation of Smad2/3, which were prevented by ALK5 inhibitor A83-01. In vivo, salusin-β overexpression increased the media thickness, media/lumen ratio coupled with ERK1/2, CREB, EGFR and Smad2/3 phosphorylation, as well as the mRNA of collagen-I, collagen-III, fibronectin, transforming growth factor-β1 (TGF-β1) and CTGF in arteries. Moreover, salusin-β overexpression in rats caused severe hypertension. Intravenous injection of salusin-β dose-relatedly increased blood pressure, but excessive salusin-β decreased blood pressure and heart rate. These results indicate that salusin-β promotes VSMC proliferation via cAMP-PKA-EGFR-CREB/ERK pathway and vascular fibrosis via TGF-β1-Smad pathway. Increased salusin-β contributes to vascular remodeling and hypertension.

The hemostatic system as a regulator of inflammation in atherosclerosis

Atherosclerosis is a chronic inflammatory disease of the arterial vessel wall. As part of a tightly connected cross-talk between inflammation and coagulation, there is growing evidence that the coagulation system plays a pivotal role in the development and progression of atherosclerosis. We here discuss the presence of coagulation factors in atherosclerotic lesions and the overall effects of hypercoagulability and hypocoagulability on atherosclerotic lesion formation. Moreover, we focus on the unifying common pathway of coagulation, which can be initiated by the intrinsic and extrinsic pathway of coagulation, and discuss the functions of the coagulation factors FX, thrombin, and FXIII as regulators of inflammation in atherosclerosis. In particular, we review the non-hemostatic and immune-modulatory functions of these factors in endothelial and smooth muscle cells, as well as monocytes/macrophages, but also other cells, such as dendritic cells and T cells, that may control the inflammatory process of atherosclerosis. Their multiple roles in coagulation, but also their non-hemostatic functions in different cell types in inflammation and immunity, may harbor great potential for the development of novel therapeutic approaches for treating cardiovascular disease.