Ligustrazine attenuates the platelet-derived growth factor-BB-induced proliferation and migration of vascular smooth muscle cells by interrupting extracellular signal-regulated kinase and P38 mitogen-activated protein kinase pathways

Cellular microarrays for assessing single-cell phenotypic changes in vascular cell populations

Microengineering technologies provide bespoke tools for single-cell studies, including microarray approaches. There are many challenges when culturing adherent single cells in confined geometries for extended periods, including the ability of migratory cells to overcome confining cell-repellent surfaces with time. Following studies suggesting clonal expansion of only a few vascular smooth muscle cells (vSMCs) contributes to plaque formation, the investigation of vSMCs at the single-cell level is central to furthering our understanding of atherosclerosis. Herein, we present a medium throughput cellular microarray, for the tracking of single, freshly-isolated vSMCs as they undergo phenotypic modulation in vitro. Our solution facilitates long-term cell confinement (> 3 weeks) utilising novel application of surface functionalisation methods to define individual culture microwells. We demonstrate successful tracking of hundreds of native vSMCs isolated from rat aortic and carotid artery tissue, monitoring their proliferative capacity and uptake of oxidised low-density lipoprotein (oxLDL) by live-cell microscopy. After 7 days in vitro, the majority of viable SMCs remained as single non-proliferating cells (51% aorta, 78% carotid). However, a sub-population of vSMCs demonstrated high proliferative capacity (≥ 10 progeny; 18% aorta, 5% carotid), in line with reports that a limited number of medial SMCs selectively expand to populate atherosclerotic lesions. Furthermore, we show that, when exposed to oxLDL, proliferative cells uptake higher levels of lipoproteins, whilst also expressing greater levels of galectin-3. Our microwell array approach enables long-term characterisation of multiple phenotypic characteristics and the identification of new cellular sub-populations in migratory, proliferative adherent cell types.

Natural ingredients from Chinese materia medica for pulmonary hypertension

Pulmonary hypertension (PH) is a severe pathophysiological condition characterized by pulmonary artery remodeling and continuous increases in pulmonary artery pressure, which may eventually develop to right heart failure and death. Although newly discovered and incredible treatment strategies in recent years have improved the prognosis of PH, limited types of effective and economical drugs for PH still makes it as a life-threatening disease. Some drugs from Chinese materia medica (CMM) have been traditionally applied in the treatment of lung diseases. Accumulating evidence suggests active pharmaceutical ingredients (APIs) derived from those medicines brings promising future for the prevention and treatment of PH. In this review, we summarized the pharmacological effects of APIs derived from CMM which are potent in treating PH, so as to provide new thoughts for initial drug discovery and identification of potential therapeutic strategies in alternative medicine for PH.

Effects of ligustrazine on the expression of neurotransmitters in the trigeminal ganglion of a rat migraine model

Background

Migraine is one of the most common neurological diseases which has been treated by active substances from traditional Chinese medicine (TCM), such as ligustrazine, an extract of the Chinese herb Chuanxiong. However, the pathogenesis of migraine and the curative mechanisms of ligustrazine have remained unclear. The genes P2X3, TRPV1, ERK, and c-fos have been implicated to play a role. In this work, we attempted to elucidate the analgesic mechanism of ligustrazine using a classic migraine-representative rat model.

Methods

The migraine rat model was established by administration of nitroglycerin (NTG). Ligustrazine treatment was administered by intravenous injection. The animal's behavior was continuously recorded, and then trigeminal ganglions (TGs) were isolated. Total RNA was extracted from cells and total protein was extracted from TG. Quantitative real-time polymerase chain reaction (qRT-PCR) and western blot analyses were used to detect the levels of P2X3, TRPV1, c-Fos, and ERK in TG.

Results

Ligustrazine could reduce the neurological activities of NTG-induced migraine rats. The rats TG nerve showed varying degrees of expression of P2X3, TRPV1, c-Fos and ERK expression element. Ligustrazine could inhibit over-expression of P2X3, TRPV1, c-fos, and ERK in the TG nerve of NTG-induced migraine rats.

Conclusions

Our results demonstrated that ligustrazine had potent activity against NTG-induced migraine rats through inhibition of the c-fos/ERK signaling pathway. This work may provide a comprehensive basis for a better understanding of the pathogenesis of migraine and the curative mechanisms of ligustrazine.

Prevention of neointimal formation after angioplasty using tetramethylpyrazine-coated balloon catheters in a rabbit iliac artery model

Background

Restenosis remains a clinical problem; drug-coated balloons (DCBs) have demonstrated high efficiency in this situation. DCBs prevent neointimal hyperplasia by inhibiting cell proliferation and migration. Tetramethylpyrazine (TMP) is a traditional Chinese medicine originally isolated from the rhizome of Ligusticum Walliichii, which can inhibit platelet aggregation and smooth muscle cell proliferation. We hypothesized that TMP-coated balloons (TCB) could reduce neointimal hyperplasia through the NF-κB signalling pathway.

Methods

Twenty-one New-Zealand White rabbits (2.5-3.0 kg, male) were fed high-fat diets; 36 bilateral iliac artery stenosis models were successfully established by balloon straining. Rabbits were randomly treated with TCB (n=20) or plain balloons (PBA, n=16) (3 died during model construction). Angiographies were recorded at baseline, the immediate period, and 4 weeks later. Animals were euthanized and arteries collected for histological analysis and immunohistochemical staining. Protein expression of proliferating cell nuclear antigen (PCNA) and nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) p65 of the vessel samples were analyzed using Western blotting.

Results

No difference existed in the baseline lesion characteristics or procedural results. Angiographic follow-up was successfully performed on 18 rabbits (TCB: n=20, PBA: n=16), except for 3 deaths related to the operation. Treatment with TCB was superior to that with PBA, with lower late lumen loss (0.45±0.23 vs. 0.84±0.17 mm, P<0.01). Pathological analysis confirmed the efficiency of TCB through decreasing the area stenosis rate compared with PBA (46.48%±8.22% vs. 75.24%±6.10%, P<0.01). As determined by Western blotting, significant reductions occurred in PCNA and NF-κB p65 protein intensity in the TCB group versus the PBA group (all P<0.01). TCB efficiently mitigated restenosis in the rabbit iliac artery model.

Conclusions

This study elucidated that TCB could restrain intimal hyperplasia of vessels by inhibiting the activation of the NF-κB pathway to reduce inflammatory response and decrease the rate of cell proliferation through suppressing PCNA expression.

7-O-methylpunctatin, a Novel Homoisoflavonoid, Inhibits Phenotypic Switch of Human Arteriolar Smooth Muscle Cells

Remodeling of arterioles is a pivotal event in the manifestation of many inflammation-based cardio-vasculopathologies, such as hypertension. During these remodeling events, vascular smooth muscle cells (VSMCs) switch from a contractile to a synthetic phenotype. The latter is characterized by increased proliferation, migration, and invasion. Compounds with anti-inflammatory actions have been successful in attenuating this phenotypic switch. While the vast majority of studies investigating phenotypic modulation were undertaken in VSMCs isolated from large vessels, little is known about the effect of such compounds on phenotypic switch in VSMCs of microvessels (microVSMCs). We have recently characterized a novel homoisoflavonoid that we called 7-O-methylpunctatin (MP). In this study, we show that MP decreased FBS-induced cell proliferation, migration, invasion, and adhesion. MP also attenuated adhesion of THP-1 monocytes to microVSMCs, abolished FBS-induced expression of MMP-2, MMP-9, and NF-κB, as well as reduced activation of ERK1/2 and FAK. Furthermore, MP-treated VSMCs showed an increase in early (myocardin, SM-22α, SM-α) and mid-term (calponin and caldesmon) differentiation markers and a decrease in osteopontin, a protein highly expressed in synthetic VSMCs. MP also reduced transcription of cyclin D1, CDK4 but increased protein levels of p21 and p27. Taken together, these results corroborate an anti-inflammatory action of MP on human microVSMCs. Therefore, by inhibiting the synthetic phenotype of microVSMCs, MP may be a promising modulator for inflammation-induced arteriolar pathophysiology.

Atheroprotective effects and molecular targets of bioactive compounds from traditional Chinese medicine

Traditional Chinese medicine (TCM) has served the Chinese people since antiquity, and is playing an important role in today's healthcare. However, there has been controversy in the use of these traditional herbs due to unclear components and absence of scientific proof. As China plans to modernize traditional medicine, successful attempts to better understand the molecular mechanisms of TCM have been made by focusing on isolating active ingredients from these remedies. In this review, we critically examined the current evidence on atheroprotective effects of bioactive compounds from TCM using in vitro or in vivo models in the past two decades. A total of 47 active compounds were included in our review, which were introduced in the order of chemical structures, source, model, efficacy and mechanism. Notablely, this review highlighted the cellular and molecular mechanisms of these active compounds in prevention and treatment of atherosclerosis. Two compounds were also involved in double-blind, randomized, placebo-controlled clinical trials (RCTs). Besides, we introduced the legislations of the People's Republic of China ensuring quality and safety of products used in TCM. In summary, studies on bioactive compounds from TCM will provide a new approach for better management of atherosclerosis.

The Signaling Pathways Involved in the Antiatherosclerotic Effects Produced by Chinese Herbal Medicines

Cardiovascular diseases (CVDs) are considered to be the predominant cause of death in the world. Chinese herb medicines (CHMs) have been widely used for the treatment of CVDs in Asian countries for thousands of years. One reason of high efficacy of CHMs in treating CVDs is attributed to their inhibition in atherosclerosis (AS) development, a critical contributor to CVDs occurrence. Cumulative studies have demonstrated that CHMs alleviate atherogenesis via mediating pathophysiologic events involved in AS. However, there is deficiency in the summaries regarding antiatherogenic signal pathways regulated by CHMs. In this review, we focus on the signal cascades by which herb medicines and relevant extractives, derivatives, and patents improve proatherogenic processes including endothelium dysfunction, lipid accumulation, and inflammation. We mainly elaborate the CHMs-mediated signaling pathways in endothelial cells, macrophages, and vascular smooth muscle cells of each pathogenic event. Moreover, we briefly describe the other AS-related factors such as thrombosis, autophagy, immune response, and noncoding RNAs and effects of CHMs on them in the way of cascade regulation, which is helpful to further illustrate the molecular mechanisms of AS initiation and progression and discover newly effective agents for AS management.

Adiponectin and its receptors are involved in hypertensive vascular injury

Adipocyte-derived adiponectin (APN) is involved in the protection against cardiovascular disease, but the endogenous APN and its receptor expression in the perivascular adipocytes and their role in hypertensive vascular injury remain unclear. The present study aimed to detect endogenous APN and its receptor expression and their protective effects against hypertensive vascular injury. APN was mainly expressed in the perivascular adipocytes, while its receptors AdipoR1 and AdipoR2 were ubiquitously expressed in the blood vessels. Angiotensin II (Ang II)-induced hypertension resulted in a significant decrease of APN and AdipoR1 and AdipoR2 in the perivascular adipocytes and vascular cells. The migration assay used demonstrated that APN attenuated Ang II-induced vascular smooth muscle cells migration and p38 phosphorylation Furthermore, the in vivo study demonstrated that APN receptor agonist AdipoRon attenuated Ang II-induced hypertensive vascular hypertrophy and fibrosis. Taken together, the present study indicated that perivascular adipocytes-derived APN attenuated hypertensive vascular injury possibly via its receptor-mediated inhibition of p38 signaling pathway.

Cellular and Molecular Mechanisms of Diabetic Atherosclerosis: Herbal Medicines as a Potential Therapeutic Approach

An increasing number of patients diagnosed with diabetes mellitus eventually develop severe coronary atherosclerosis disease. Both type 1 and type 2 diabetes mellitus increase the risk of cardiovascular disease associated with atherosclerosis. The cellular and molecular mechanisms affecting the incidence of diabetic atherosclerosis are still unclear, as are appropriate strategies for the prevention and treatment of diabetic atherosclerosis. In this review, we discuss progress in the study of herbs as potential therapeutic agents for diabetic atherosclerosis.

Gene expression profiles and signaling mechanisms in α2B-adrenoceptor-evoked proliferation of vascular smooth muscle cells

BACKGROUND

α2-adrenoceptors are important regulators of vascular tone and blood pressure. Regulation of cell proliferation is a less well investigated consequence of α2-adrenoceptor activation. We have previously shown that α2B-adrenoceptor activation stimulates proliferation of vascular smooth muscle cells (VSMCs). This may be important for blood vessel development and plasticity and for the pathology and therapeutics of cardiovascular disorders. The underlying cellular mechanisms have remained mostly unknown. This study explored pathways of regulation of gene expression and intracellular signaling related to α2B-adrenoceptor-evoked VSMC proliferation.

RESULTS

The cellular mechanisms and signaling pathways of α2B-adrenoceptor-evoked proliferation of VSMCs are complex and include redundancy. Functional enrichment analysis and pathway analysis identified differentially expressed genes associated with α2B-adrenoceptor-regulated VSMC proliferation. They included the upregulated genes Egr1, F3, Ptgs2 and Serpine1 and the downregulated genes Cx3cl1, Cav1, Rhoa, Nppb and Prrx1. The most highly upregulated gene, Lypd8, represents a novel finding in the VSMC context. Inhibitor library screening and kinase activity profiling were applied to identify kinases in the involved signaling pathways. Putative upstream kinases identified by two different screens included PKC, Raf-1, Src, the MAP kinases p38 and JNK and the receptor tyrosine kinases EGFR and HGF/HGFR. As a novel finding, the Src family kinase Lyn was also identified as a putative upstream kinase.

CONCLUSIONS

α2B-adrenoceptors may mediate their pro-proliferative effects in VSMCs by promoting the activity of bFGF and PDGF and the growth factor receptors EGFR, HGFR and VEGFR-1/2. The Src family kinase Lyn was also identified as a putative upstream kinase. Lyn is known to be expressed in VSMCs and has been identified as an important regulator of GPCR trafficking and GPCR effects on cell proliferation. Identified Ser/Thr kinases included several PKC isoforms and the β-adrenoceptor kinases 1 and 2. Cross-talk between the signaling mechanisms involved in α2B-adrenoceptor-evoked VSMC proliferation thus appears to involve PKC activation, subsequent changes in gene expression, transactivation of EGFR, and modulation of kinase activities and growth factor-mediated signaling. While many of the identified individual signals were relatively small in terms of effect size, many of them were validated by combining pathway analysis and our integrated screening approach.

Mechanisms and Clinical Application of Tetramethylpyrazine (an Interesting Natural Compound Isolated from Ligusticum Wallichii): Current Status and Perspective

Tetramethylpyrazine, a natural compound from Ligusticum wallichii (Chuan Xiong), has been extensively used in China for cardiovascular and cerebrovascular diseases for about 40 years. Because of its effectiveness in multisystems, especially in cardiovascular, its pharmacological action, clinical application, and the structural modification have attracted broad attention. In this paper its mechanisms of action, the clinical status, and synthetic derivatives will be reviewed briefly.

Oleanolic acid suppresses vascular smooth muscle cell proliferation by increasing lincRNA-p21 expression

Arteriosclerosis poses a significant risk to human health and involves the thickening and hardening of the walls of arteries. Accumulated evidence demonstrates that aberrant proliferation of vascular smooth muscle cells (VSMCs) accounts for the onset and progression of arteriosclerosis. Suppression of their proliferation has been demonstrated to be an effective anti-arteriosclerosis strategy. Long non-coding RNAs (lncRNAs) have recently been observed to be implicated in the proliferation of VSMCs and arteriosclerosis. In this study, we observed that oleanolic acid (OA), a natural compound from plants, inhibited the proliferation of VSMCs. The expression of lincRNA-p21, an arteriosclerosis-associated lncRNA, was demonstrated to be elevated by OA treatment. Suppression of lincRNA-p21 rescued the effect of OA on the proliferation of VSMCs. Collectively, targeting lncRNA is a promising strategy for arteriosclerosis prevention and treatment, and OA ameliorates arteriosclerosis by increasing lncRNA levels.

A Novel Protective Function of 5-Methoxytryptophan in Vascular Injury

5-Methoxytryptophan (5-MTP), a 5-methoxyindole metabolite of tryptophan metabolism, was recently shown to suppress inflammatory mediator-induced cancer cell proliferation and migration. However, the role of 5-MTP in vascular disease is unknown. In this study, we investigated whether 5-MTP protects against vascular remodeling following arterial injury. Measurements of serum 5-MTP levels in healthy subjects and patients with coronary artery disease (CAD) showed that serum 5-MTP concentrations were inversely correlated with CAD. To test the role of 5-MTP in occlusive vascular disease, we subjected mice to a carotid artery ligation model of neointima formation and treated mice with vehicle or 5-MTP. Compared with vehicle-treated mice, 5-MTP significantly reduced intimal thickening by 40% 4 weeks after ligation. BrdU incorporation assays revealed that 5-MTP significantly reduced VSMC proliferation both in vivo and in vitro. Furthermore, 5-MTP reduced endothelial loss and detachment, ICAM-1 and VCAM-1 expressions, and inflammatory cell infiltration in the ligated arterial wall, suggesting attenuation of endothelial dysfunction. Signaling pathway analysis indicated that 5-MTP mediated its effects predominantly via suppressing p38 MAPK signaling in endothelial and VSMCs. Our data demonstrate a novel vascular protective function of 5-MTP against arterial injury-induced intimal hyperplasia. 5-MTP might be a therapeutic target for preventing and/or treating vascular remodeling.