Angiogenic activity of sesamin through the activation of multiple signal pathways

Screening of herbal extracts binding with vascular endothelial growth factor by applying HerboChip platform

BACKGROUND

Traditional Chinese medicine (TCM) has been hailed as a rich source of medicine, but many types of herbs and their functions still need to be rapidly discovered and elucidated. HerboChip, a target-based drug screening platform, is an array of different fractions deriving from herbal extracts. This study was designed to identify effective components from TCM that interact with vascular endothelial growth factor (VEGF) as a target using HerboChip.

METHODS

Selected TCMs that are traditionally used as remedies for cancer prevention and wound healing were determined and extracted with 50% ethanol. Biotinylated-VEGF was hybridized with over 500 chips coated with different HPLC-separated fractions from TCM extracts and straptavidin-Cy5 was applied to identify plant extracts containing VEGF-binding fractions. Cytotoxicity of selected herbal extracts and their activities on VEGF-mediated angiogenic functions were evaluated.

RESULTS

Over 500 chips were screened within a week, and ten positive hits were identified. The interaction of the identified herbal extracts with VEGF was confirmed in cultured endothelial cells. The identified herbs promoted or inhibited VEGF-mediated cell proliferation, migration and tube formation. Results from western blotting analysis demonstrated the identified herbal extracts significantly affected VEGF-triggered phosphorylations of eNOS, Akt and Erk. Five TCMs demonstrated potentiating activities on the VEGF response and five TCMs revealed suppressive activities.

CONCLUSIONS

The current results demonstrated the applicability of the HerboChip platform and systematically elucidated the activity of selected TCMs on angiogenesis and its related signal transduction mechanisms.

The Potential Use of Vitamin D3 and Phytochemicals for Their Anti-Ageing Effects

Unlike other vitamins, vitamin D3 is synthesised in skin cells in the body. Vitamin D3 has been known as a bone-related hormone. Recently, however, it has been considered as an immune vitamin. Vitamin D3 deficiency influences the onset of a variety of diseases. Vitamin D3 regulates the production of proinflammatory cytokines such as tumour necrosis factor-α (TNF-α) through binding to vitamin D receptors (VDRs) in immune cells. Since blood levels of vitamin D3 (25-OH-D3) were low in coronavirus disease 2019 (COVID-19) patients, there has been growing interest in the importance of vitamin D3 to maintaining a healthy condition. On the other hand, phytochemicals are compounds derived from plants with over 7000 varieties and have various biological activities. They mainly have health-promoting effects and are classified as terpenoids, carotenoids, flavonoids, etc. Flavonoids are known as the anti-inflammatory compounds that control TNF-α production. Chronic inflammation is induced by the continuous production of TNF-α and is the fundamental cause of diseases like obesity, dyslipidaemia, diabetes, heart and brain diseases, autoimmune diseases, Alzheimer's disease, and cancer. In addition, the ageing process is induced by chronic inflammation. This review explains the cooperative effects of vitamin D3 and phytochemicals in the suppression of inflammatory responses, how it balances the natural immune response, and its link to anti-ageing effects. In addition, vitamin D3 and phytochemicals synergistically contribute to anti-ageing by working with ageing-related genes. Furthermore, prevention of ageing processes induced by the chronic inflammation requires the maintenance of healthy gut microbiota, which is related to daily dietary habits. In this regard, supplementation of vitamin D3 and phytochemicals plays an important role. Recently, the association of the prevention of the non-disease condition called "ME-BYO" with the maintenance of a healthy condition has been an attractive regimen, and the anti-ageing effect discussed here is important for a healthy and long life.

Sesame cake extract attenuates dextran sulfate sodium-induced colitis through inhibition of oxidative stress in mice

Inflammatory bowel disease (IBD) is a chronic inflammatory disease occurring in the gut causing chronic diarrhea and abdominal pain with severe complications. Sesame cake is a by-product of sesame oil production, possessing various beneficial properties; however, little is known about the effect of sesame cake extract (SCE) against IBD. The aim of this study was to investigate the protective effect of SCE against dextran sulfate sodium (DSS)-induced colitis in mice. Administration of SCE was first performed at 7 days before treating mice with 2.5% DSS to induce colitis for 7 days. SCE pretreatment improved symptoms of DSS-induced colitis. In addition, SCE ameliorated histopathological damages of the mucus layer in colon tissues and decreased pro-inflammatory cytokines in colitis-induced mice. SCE also suppressed apoptosis and oxidative stress in colitis-induced colon tissues. Together, these findings suggest that SCE could be potential nutraceuticals for treating colitis.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10068-023-01367-1.

Calcium-Catalyzed Synthesis of Fused Furo[2,3-b]furans and Substituted Furans from 2-Oxo Aldehydes and Cyclic Enols

We report here an atom-economical, syn-diastereoselective synthesis of naphtho-fused furo[2,3-b]furans along with naphthofurans at room temperature using readily available 2-naphthols and 2-oxo aldehydes using an alkaline earth catalyst [Ca(OTf)2]. 2-Oxo aldehydes having both aryl and alkyl substitutions reacted well. A good number of arenols responded to give fused furans, but selected arenols gave only furofurans. Synthetic applications and gram-scale synthesis were also demonstrated to strengthen this strategy.

The role of the ERK signaling pathway in promoting angiogenesis for treating ischemic diseases

The main treatment strategy for ischemic diseases caused by conditions such as poor blood vessel formation or abnormal blood vessels involves repairing vascular damage and encouraging angiogenesis. One of the mitogen-activated protein kinase (MAPK) signaling pathways, the extracellular signal-regulated kinase (ERK) pathway, is followed by a tertiary enzymatic cascade of MAPKs that promotes angiogenesis, cell growth, and proliferation through a phosphorylation response. The mechanism by which ERK alleviates the ischemic state is not fully understood. Significant evidence suggests that the ERK signaling pathway plays a critical role in the occurrence and development of ischemic diseases. This review briefly describes the mechanisms underlying ERK-mediated angiogenesis in the treatment of ischemic diseases. Studies have shown that many drugs treat ischemic diseases by regulating the ERK signaling pathway to promote angiogenesis. The prospect of regulating the ERK signaling pathway in ischemic disorders is promising, and the development of drugs that specifically act on the ERK pathway may be a key target for promoting angiogenesis in the treatment of ischemic diseases.

Sesamin Attenuates VEGFA-Induced Angiogenesis via Inhibition of Src and FAK Signaling in Chick Chorioallantoic Membrane Model and Human Endothelial EA.hy926 Cells

Sesamin, a major phytochemical in sesame seeds and oil, has been reported to have effects on physiological and pathological angiogenesis in several studies. Nevertheless, the underlying mechanisms of sesamin's effect on angiogenesis are not understood well enough. This study aimed to investigate its effect on both physiological and pathological angiogenesis using the in vivo chick chorioallantoic membrane (CAM) model and the in vitro human endothelial cell line, EA.hy926, model. Sesamin inhibited the VEGFA-induced pathological angiogenesis significantly, although no effect was seen on angiogenesis without induction. It reduced the formation of vascular branches in the VEGFA-treated CAMs and also the proliferation and migration of EA.hy926 endothelial cells induced by VEGFA. Sesamin impeded the VEGF-mediated activation of Src and FAK signaling proteins, which may be responsible for sesamin-mediated reduction of pathological angiogenesis. Moreover, the effect of sesamin on the expressions of angiogenesis-related genes was then investigated and it was found that both mRNA and protein expressions of Notch1, the key pathway in vascular development, induced by VEGFA, were significantly reduced by sesamin. Our results altogether suggested that sesamin, by inhibiting pathological angiogenesis, has the potential to be employed in the prevention or treatment of diseases with over-angiogenesis, such as cancers.

Inhibition Potencies of Phytochemicals Derived from Sesame Against SARS-CoV-2 Main Protease: A Molecular Docking and Simulation Study

The ongoing COVID-19 pandemic, caused by SARS-CoV-2, has now spread across the nations with high mortality rates and multifaceted impact on human life. The proper treatment methods to overcome this contagious disease are still limited. The main protease enzyme (Mpro, also called 3CLpro) is essential for viral replication and has been considered as one of the potent drug targets for treating COVID-19. In this study, virtual screening was performed to find out the molecular interactions between 36 natural compounds derived from sesame and the Mpro of COVID-19. Four natural metabolites, namely, sesamin, sesaminol, sesamolin, and sesamolinol have been ranked as the top interacting molecules to Mpro based on the affinity of molecular docking. Moreover, stability of these four sesame-specific natural compounds has also been evaluated using molecular dynamics (MD) simulations for 200 nanoseconds. The molecular dynamics simulations and free energy calculations revealed that these compounds have stable and favorable energies, causing strong binding with Mpro. These screened natural metabolites also meet the essential conditions for drug likeness such as absorption, distribution, metabolism, and excretion (ADME) properties as well as Lipinski's rule of five. Our finding suggests that these screened natural compounds may be evolved as promising therapeutics against COVID-19.

The combination of two natural medicines, Chuanxiong and Asarum: A review of the chemical constituents and pharmacological activities

Traditional Chinese medicine has been clinically used in China for many years, with experimental studies and clinical trials having demonstrated that it is safe and valid. Among many traditional natural medicines, Chuanxiong and Asarum have been proven to be effective in the treatment of relieving pain. Actually, as well as analgesic, they have common attributes, such as anti-inflammatory, cardiovascular benefits, and anticancer activities, with volatile oils being their major components. Furthermore, Chuanxiong and Asarum have been combined as drug pairs in the same prescription for thousands of years, with examples being Chuanxiong Chatiao San and Chuanxiongxixintang. More interestingly, their combination has better therapeutic effects on diseases than a single drug. After the combination of Chuanxiong and Asarum forms a blend, a series of changes take place in their chemical components, such as the contents of the main active ingredients, ferulic acid and ligustilide, increased significantly after this progress. At the same time, the pharmacological effects of the combination appearing to be more powerful, such as synergistic analgesic. This review focuses on the chemical constituents and pharmacological activities of Chuanxiong, Asarum, and Chuanxiong Asarum compositions.

Immunomodulatory and anti-inflammatory effects of sesamin: mechanisms of action and future directions

Inflammation is associated with the development and progression of various disorders including atherosclerosis, diabetes mellitus and cancer. Sesamin, a fat-soluble lignan derived from Sesamum indicum seeds and oil, has received increased attention due to its wide array of pharmacological properties including its immunomodulatory and anti-inflammatory potential. To date, no review has been conducted to summarize or analyze the immunomodulatory and anti-inflammatory roles of sesamin. Herein, we provide a comprehensive review of experimental findings that were reported with regards to the ability of sesamin to modulate inflammation, cellular and humoral adaptive immune responses and Th1/Th2 paradigm. The potential influence of sesamin on the cytotoxic activity of NK cells against cancer cells is also highlighted. The molecular mechanisms and the signal transduction pathways underlying such effects are underscored. The metabolism, pharmacokinetics, absorption, tissue distribution and bioavailability of sesamin in different species, including humans, are reviewed. Moreover, we propose future preclinical and clinical investigations to further validate the potential preventive and/or therapeutic efficacy of sesamin against various immune-related and inflammatory conditions. We anticipate that sesamin may be employed in future therapeutic regimens to enhance the efficacy of treatment and dampen the adverse effects of synthetic chemical drugs currently used to alleviate immune-related and inflammatory conditions.

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.

Crocetin promotes angiogenesis in human endothelial cells through PI3K-Akt-eNOS signaling pathway

Previous studies proved the pro-angiogenic effect of Crocetin, a natural carotenoid dicarboxylic acid, in both in vivo and in vitro models. However, the exact mechanism of Crocetin action has not completely been elucidated yet. The current experiment was designed to find the activity of PI3K-Akt-eNOS axis after the treatment of endothelial cells with Crocetin in vitro. Human Umbilical Vein Endothelial Cells (HUVECs) were incubated with various concentrations of Crocetin (1, 5, 25, 50, and 100 µM) over a period of 72 h. Crocetin significantly increased HUVECs viability after 72 h as compared with the control group. We also found that Crocetin promoted the formation of the capillary-like structure compared to the control (p<0.05). Moreover, an improved migration rate and increased MMP-9 activity were observed in HUVECs that received 50 µM Crocetin (p<0.05). Crocetin enhanced the uptake of Ac-LDL which is correlated with increased lipid metabolism. Based on the data from the current experiment, protein level of VEGFR-1, -2 and p-Akt/Akt, p-eNOS/eNOS ratios were increased 72 h after the treatment of HUVECs with Crocetin (p<0.05). In contrast, the transcription level of VEGF was reduced in Crocetin-treated cells. These data demonstrated that Crocetin promotes HUVECs angiogenesis potential by the modulation of VEGF signaling pathway and increased cell viability. The PI3K/Akt/eNOS axis is required for a Crocetin-associated activity in endothelial cells.

Sesamin Enhances Nrf2-Mediated Protective Defense against Oxidative Stress and Inflammation in Colitis via AKT and ERK Activation

Ulcerative colitis (UC) is a major form of inflammatory bowel disease (IBD) with high incidence and prevalence in many countries. Patients with UC usually suffer from a lifetime of debilitating physical symptoms. Therefore, developing effective therapeutic strategy that can manage this disease better and improve patients' life quality is in urgent need. Sesamin (SSM) is a lignan derived from sesame seeds. In this study, the protective effect of SSM against UC and the underlying mechanism were investigated in vitro and in vivo. Our data showed that SSM protected Caco-2 cells from H₂O₂-induced oxidative stress injury via GSH-mediated scavenging of reactive oxygen species (ROS). Dual luciferase reporter assay showed that the transcriptional activity of nuclear factor erythroid-related factor 2 (Nrf2) was significantly increased by SSM, and the ability of SSM to activate Nrf2-targeted genes was further confirmed in Caco-2 cells using western blot and quantitative real-time PCR (qRT-PCR). In contrast, Nrf2 knockdown abolished the protective effect of SSM. Additionally, we found that SSM also activated advanced protein kinase B (AKT) and extracellular signal-regulated kinase (ERK) in Caco-2 cells, while either AKT or ERK inhibition can prevent SSM-mediated nuclear translocation of Nrf2. Furthermore, SSM displayed a better protective effect against dextran sulfate sodium- (DSS-) induced UC compared with 5-aminosalicylic acid (5-ASA) in C57BL/6 mice. The enhanced Nrf2 signaling and activated AKT/ERK were also observed in the colon of mice after SSM administration. These results first demonstrate the protective effect of SSM against UC and indicate that the effect is associated with AKT/ERK activation and subsequent Nrf2 signaling enhancement. This study provides a new insight into the medicinal value of SSM and proposes it as a new natural nutrition for better managing the symptoms of UC.

Recovery of Sesamin, Sesamolin, and Minor Lignans From Sesame Oil Using Solid Support-Free Liquid-Liquid Extraction and Chromatography Techniques and Evaluation of Their Enzymatic Inhibition Properties

In this study, an integrated process for the recovery of sesamin and sesamolin, two high added-value lignans of sesame oil (SO) was developed, using synchronous extraction and chromatography techniques. The extraction of SO phenolic content was studied using two different extraction techniques: Annular centrifugal extraction (ACE) and centrifugal partition extraction (CPE). The derived data of each experiment were compared in terms of revealing the yields, time, and solvents consumption showing that CPE is the most effective technique, concerning the solvent consumption. The isolation of lignans was achieved using centrifugal partition chromatography (CPC) both on semi-preparative and preparative scale. The biphasic system used for this purpose consisted of the following solvents: n-Hex/EtOAc/EtOH/H₂O in proportion 2:3:3:2 (v/v/v/v) and direct recovery of the two major lignans sesamin and sesamolin was achieved. In parallel the CPC analysis resulted in the isolation of four minor lignans of sesame oil, i.e., samin, sesamol, sesaminol, and episesaminol. Structure elucidation of isolated lignans was based on HRMS/MS and NMR experiments. High-performance liquid chromatography (HPLC) was employed for quantitative analysis of the obtained extracts to determine the purity of the isolated compounds as well. The results of this study demonstrated that sesamin and sesamolin were recovered in purity higher than 95%, verifying the effectiveness of the purposed separation methodology. Finally, due to the general application of sesame oil in cosmetic industry, all the pure compounds were evaluated for their tyrosinase, elastase, collagenase, and hyaluronidase inhibition activity.

Sesamin Protects the Femoral Head From Osteonecrosis by Inhibiting ROS-Induced Osteoblast Apoptosis in Rat Model

Glucocorticoids intake has become the most common pathogenic factor for osteonecrosis of the femoral head (ONFH). Annually, tens of millions of patients suffer from pain related to ONFH. Researchers have proposed several underlying mechanisms of ONFH, including osteocyte apoptosis, cell differentiation disorder, and angiogenesis hindrance. Sesamin, isolated from Sesamum indicum seeds, was reported could affect osteocyte inflammation and differentiation in osteoarthritis and osteoporosis. We investigated the underlying influence of sesamin on ONFH rat model. Fifteen male Sprague-Dawley rats were randomly divided into three groups. The ONFH model group only received the methylprednisolone (MPS) and lipopolysaccharide (LPS) injection to promote the development of ONFH. The sesamin treatment group was injected with sesamin, MPS, and LPS. The control group was untreated. Rats from above groups were sacrificed 4 weeks later. The effect of sesamin on ONFH rats was validated by H&E staining. TUNEL staining showed that femoral head necrosis was attenuated by sesamin. Furthermore, the phosphorylation of Akt was increased and the downstream cellular apoptosis signal pathway was inhibited. Intracellular ROS level was decreased after sesamin treatment. In conclusion, our findings suggest that sesamin protects the femoral head from osteonecrosis by inhibiting ROS-induced osteoblast apoptosis.

The extract of Polygoni Cuspidati Rhizoma et Radix suppresses the vascular endothelial growth factor-induced angiogenesis

BACKGROUND

Polygoni Cuspidati Rhizoma et Radix (PCRR; the root and rhizome of Polygonum cuspidatum Sieb. et Zucc) is a traditional Chinese medicine for the treatment of inflammation, hyperlipemia, favus, jaundice and scald.

HYPOTHESIS/PURPOSE

The extract of PCRR inhibits vascular endothelial growth factor (VEGF)-induced angiogenesis. The hypothesis is supported by analysis of PCRR extract and investigation of pharmacological role and signaling mechanism of PCRR extract in regulating angiogenic responses.

STUDY DESIGN

The PCRR ethanolic extract was examined for its inhibitory effects on angiogenesis based on VEGF-treated human umbilical vein endothelial cells and in zebrafish model METHODS: The effects and signaling mechanism of a standardized ethanolic extract of PCRR were tested on cell proliferation, migration and tube formation in VEGF-treated human umbilical vein endothelial cells, and which was further validated in zebrafish embryo model.

RESULTS

The treatment of PCRR extract in cultured endothelial cells inhibited VEGF-induced cell proliferation, cell migration and tube formation in a dose-dependent manner and also suppressed the formation of sub-intestinal vessels in zebrafish embryos. Moreover, the applied PCRR extract suppressed VEGF-induced phosphorylations of VEGF receptor 2 (VEGFR2) and JNK. Thus, the site of effect triggered by PCRR was proposed to be mediated by VEGFR2. To further support this notion, the phosphorylations of Erk, Akt and eNOS, induced by VEGF, were markedly reduced under the challenge of PCRR extract: the reductions were subsequently further decreased in the present of inhibitors of Erk, Akt and eNOS. In parallel, the formation of ROS induced by VEGF in cultured endothelial cells was markedly reduced in the present of PCRR extract.

CONCLUSION

Collectively, our studies demonstrated the pharmacological role and signaling mechanism of PCRR in regulation of angiogenic responses, which supported further evaluation and development of PCRR as a potential therapeutic agent for the treatment and prevention of diseases related with angiogenesis.

Effects of metformin on inflammation and short-term memory in streptozotocin-induced diabetic mice

The aim of the present study was to analyze the action of metformin on short-term memory, glial cell activation and neuroinflammation caused by experimental diabetic encephalopathy in C57BL/6 mice. Diabetes was induced by the intraperitoneal injection of a dose of 90mg/kg of streptozotocin on two successive days. Mice with blood glucose levels ≥200dl/ml were considered diabetic and were given metformin hydrochloride at doses of 100mg/kg and 200mg/kg (by gavage, twice daily) for 21 days. On the final day of treatment, the mice underwent a T-maze test. On the 22nd day of treatment all the animals were anesthetized and euthanized. Diabetic animals treated with metformin had a higher spatial memory score. The hippocampus of the diabetic animals presented reactive gliosis, neuronal loss, NF-kB signaling activation, and high levels of IL-1 and VEGF. In addition, the T-maze test scores of these animals were low. Treatment with metformin reduced the expression of GFAP, Iba-1 (astrocyte and microglial markers) and the inflammation markers (p-IKB, IL-1 and VEGF), while enhancing p-AMPK and eNOS levels and increasing neuronal survival (Fox-1 and NeuN). Treatment with metformin also improved the spatial memory scores of diabetic animals. In conclusion, the present study showed that metformin can significantly reduce neuroinflammation and can decrease the loss of neurons in the hippocampus of diabetic animals, which can subsequently promote improvements in spatial memory.

Pro-angiogenic activity of notoginsenoside R1 in human umbilical vein endothelial cells in vitro and in a chemical-induced blood vessel loss model of zebrafish in vivo

OBJECTIVE

This study aimed at investigating whether notoginsenoside R1 (R1), a unique saponin found in Panax notoginseng could promote angiogenic activity on human umbilical vein endothelial cells (HUVECs) and elucidate their potential molecular mechanisms. In addition, vascular restorative activities of R1 was assessed in a chemically-induced blood vessel loss model in zebrafish.

METHODS

The in vitro angiogenic effect of R1 was compared with other previously reported angiogenic saponins Rg1 and Re. The HUVECs proliferation in the presence of R1 was determined by cell proliferation kit II (XTT) assay. R1, Rg1 and Re-induced HUVECs invasion across polycarbonate membrane was stained with Hoechst-33342 and quantified microscopically. Tube formation assay using matrigelcoated wells was performed to evaluate the pro-angiogenic actions of R1. In order to understand the mechanism underlying the pro-angiogenic effect, various pathway inhibitors such as SU5416, wortmannin (wort) or L-Nω-nitro- L-arginine methyl ester hydrochloride (L-NAME), SH-6 were used to probe the possible involvement of signaling pathway in the R1 mediated HUVECs proliferation. In in vivo assays, zebrafish embryos at 21 hpf were pre-treated with vascular endothelial growth factor (VEGF) receptor kinase inhibitor II (VRI) for 3 h only and subsequently post-treated with R1 for 48 h, respectively. The intersegmental vessels (ISVs) in zebrafish were assessed for the restorative effect of R1 on defective blood vessels.

RESULTS

R1 could stimulate the proliferation of HUVECs. In the chemoinvasion assay, R1 significantly increased the number of cross-membrane HUVECs. In addition, R1 markedly enhanced the tube formation ability of HUVECs. The proliferative effects of these saponins on HUVECs were effectively blocked by the addition of SU5416 (a VEGF-KDR/Flk-1 inhibitor). Similarly, pre-treatment with wort [a phosphatidylinositol 3-kinase (PI3K)-kinase inhibitor], L-NAME [an endothelial nitric oxide synthase (eNOS) inhibitor] or SH-6 (an Akt pathway inhibitor) significantly abrogated the R1 induced proliferation of HUVECs. In chemicallyinduced blood vessel loss model in zebrafish, R1 significantly rescue the damaged ISVs.

CONCLUSION

R1, similar to Rg1 and Re, had been showed pro-angiogenic action, possibly via the activation of the VEGF-KDR/Flk-1 and PI3K-Akt-eNOS signaling pathways. Our findings also shed light on intriguing pro-angiogenic effect of R1 under deficient angiogenesis condition in a pharmacologic-induced blood vessels loss model in zebrafish. The present study in vivo and in vitro provided scientific evidence to explain the ethnomedical use of Panax notoginseng in the treatment of cardiovascular diseases, traumatic injuries and wound healing.

Specific activation of insulin-like growth factor-1 receptor by ginsenoside Rg5 promotes angiogenesis and vasorelaxation

Ginsenoside Rg5 is a compound newly synthesized during the steaming process of ginseng; however, its biological activity has not been elucidated with regard to endothelial function. We found that Rg5 stimulated in vitro angiogenesis of human endothelial cells, consistent with increased neovascularization and blood perfusion in a mouse hind limb ischemia model. Rg5 also evoked vasorelaxation in aortic rings isolated from wild type and high cholesterol-fed ApoE(-/-) mice but not from endothelial nitric-oxide synthase (eNOS) knock-out mice. Angiogenic activity of Rg5 was highly associated with a specific increase in insulin-like growth factor-1 receptor (IGF-1R) phosphorylation and subsequent activation of multiple angiogenic signals, including ERK, FAK, Akt/eNOS/NO, and Gi-mediated phospholipase C/Ca(2+)/eNOS dimerization pathways. The vasodilative activity of Rg5 was mediated by the eNOS/NO/cGMP axis. IGF-1R knockdown suppressed Rg5-induced angiogenesis and vasorelaxation by inhibiting key angiogenic signaling and NO/cGMP pathways. In silico docking analysis showed that Rg5 bound with high affinity to IGF-1R at the same binding site of IGF. Rg5 blocked binding of IGF-1 to its receptor with an IC50 of ∼90 nmol/liter. However, Rg5 did not induce vascular inflammation and permeability. These data suggest that Rg5 plays a novel role as an IGF-1R agonist, promoting therapeutic angiogenesis and improving hypertension without adverse effects in the vasculature.

Phytochemical profile of Paulownia tomentosa (Thunb). Steud

Paulownia tomentosa, a member of the plant family Paulowniaceae and a rich source of biologically active secondary metabolites, is traditionally used in Chinese herbal medicine. Flavonoids, lignans, phenolic glycosides, quinones, terpenoids, glycerides, phenolic acids, and miscellaneous other compounds have been isolated from different parts of P. tomentosa plant. Recent interest in this species has focused on isolating and identifying of prenylated flavonoids, that exhibit potent antioxidant, antibacterial, and antiphlogistic activities and inhibit severe acute respiratory syndrome coronavirus papain-like protease. They show cytotoxic activity against various human cancer cell lines and inhibit the effects of human cholinesterase, butyrylcholinesterase, and bacterial neuraminidases. Most of the compounds considered here have never been isolated from any other species of plant. This review summarizes the information about the isolated compounds that are active, their bioactivities, and the structure-activity relationships that have been worked out for them.

In vivo angiogenesis screening and mechanism of action of novel tanshinone derivatives produced by one-pot combinatorial modification of natural tanshinone mixture from Salvia miltiorrhiza

Background

Natural products present in low quantity in herb medicines constitute an important source of chemical diversity. However, the isolation of sufficient amounts of these low abundant constituents for structural modification has been a challenge for several decades and subsequently halts research on the utilization of this important source of chemical entities for drug discovery and development. And, pro-angiogenic therapies are being explored as options to treat cardio-cerebral vascular diseases and wound healing recently. The present study investigates the pro-angiogenic potential of tanshinone derivatives produced by one-pot synthesis using zebrafish model.

Methodology/Principal Findings

In order to address the difficulty of chemical modification of low abundant constituents in herb medicines, a novel one-pot combinatorial modification was used to diversify a partially purified tanshinone mixture from Salvia miltiorrhiza. This led to the isolation of ten new imidazole-tanshinones (Compounds 1–10) and one oxazole-tanshinone (Compound 11), the structures of which were characterized by spectroscopic methods in combination with single-crystal X-ray crystallographic analysis. The angiogenesis activities of the new tanshinone derivatives were determined in an experimental model of chemical-induced blood vessels damage in zebrafish. Of all the tested new derivatives, compound 10 exhibited the most potent vascular protective and restorative activity with an EC₅₀ value of 0.026 µM. Moreover, the mechanism underlying the pro-angiogenesis effect of 10 probably involved the VEGF/FGF-Src-MAPK and PI3K-P38 signalling pathways by gene expression analysis and a blocking assay with pathways-specific kinase inhibitors.

Conclusions/Significance

Taken together, our study demonstrated the more distinctive pro-angiogenic properties of 10 than other tanshinones and revealed 10 has potential for development as a pro-angiogenic agent for diseases associated with insufficient angiogenesis. Our results highlighted the great potential of adopting a newly modified one-pot approach to enhance the chemical diversity and biological activities of constituents from natural products regardless of their abundances.

Hepatocyte growth factor stimulated angiogenesis without inflammation: differential actions between hepatocyte growth factor, vascular endothelial growth factor and basic fibroblast growth factor

Based on the potent angiogenic effects of hepatocyte growth factor (HGF), therapeutic angiogenesis using human HGF plasmid DNA increased tissue perfusion and reduced symptoms in patients with critical limb ischemia (CLI) in randomized placebo-controlled clinical trials. To explore further the potent angiogenic activity of HGF, the present study compared the effects of HGF, vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF) on angiogenesis and vascular inflammation. All of HGF, VEGF and bFGF significantly induced the formation of capillary blood vessel and granulation tissue in the rat paper disc model as an in vivo animal model of angiogenesis. However, although HGF, bFGF and VEGF significantly increased the growth of vascular endothelial cells, bFGF alone, but not HGF or VEGF, significantly increased the growth of vascular smooth muscle cells (VSMCs) in the in vitro proliferation assay. In addition, bFGF, but not HGF or VEGF, significantly activated an essential transcription factor for inflammation, NFκB, and gene expression of its downstream inflammation-related cytokines (IL-8 and MCP-1) in VSMCs, accompanied by an increase in the vascular permeability in the rat paper disc model. Thus, the present results indicated that HGF induced angiogenesis without vascular inflammation, different from bFGF and VEGF. These different properties between HGF, VEGF and bFGF might affect the efficiency of therapeutic angiogenesis.

Syringaresinol causes vasorelaxation by elevating nitric oxide production through the phosphorylation and dimerization of endothelial nitric oxide synthase

Nitric oxide (NO) produced by endothelial NO synthase (eNOS) plays an important role in vascular functions, including vasorelaxation. We here investigated the pharmacological effect of the natural product syringaresinol on vascular relaxation and eNOS-mediated NO production as well as its underlying biochemical mechanism in endothelial cells. Treatment of aortic rings from wild type, but not eNOS(-/-) mice, with syringaresinol induced endothelium-dependent relaxation, which was abolished by addition of the NOS inhibitor N(G)-monomethyl-L-arginine. Treatment of human endothelial cells and mouse aortic rings with syringaresinol increased NO production, which was correlated with eNOS phosphorylation via the activation of Akt and AMP kinase (AMPK) as well as elevation of intracellular Ca(2+) levels. A phospholipase C (PLC) inhibitor blocked the increases in intracellular Ca(2+) levels, AMPK-dependent eNOS phosphorylation, and NO production, but not Akt activation, in syringaresinol- treated endothelial cells. Syringaresinol-induced AMPK activation was inhibited by co-treatment with PLC inhibitor, Ca(2+) chelator, calmodulin antagonist, and CaMKKβ siRNA. This compound also increased eNOS dimerization, which was inhibited by a PLC inhibitor and a Ca(2+)-chelator. The chemicals that inhibit eNOS phosphorylation and dimerization attenuated vasorelaxation and cGMP production. These results suggest that syringaresinol induces vasorelaxation by enhancing NO production in endothelial cells via two distinct mechanisms, phosphatidylinositol 3-kinase/Akt- and PLC/Ca(2+)/CaMKKβ-dependent eNOS phosphorylation and Ca(2+)-dependent eNOS dimerization.

Ellagic acid, a phenolic compound, exerts anti-angiogenesis effects via VEGFR-2 signaling pathway in breast cancer

Anti-angiogenesis targeting VEGFR-2 has been considered as an important strategy for cancer therapy. Ellagic acid is a naturally existing polyphenol widely found in fruits and vegetables. It was reported that ellagic acid interfered with some angiogenesis-dependent pathologies. Yet the mechanisms involved were not fully understood. Thus, we analyzed its anti-angiogenesis effects and mechanisms on human breast cancer utilizing in-vitro and in-vivo methodologies. The in-silico analysis was also carried out to further analyze the structure-based interaction between ellagic acid and VEGFR-2. We found that ellagic acid significantly inhibited a series of VEGF-induced angiogenesis processes including proliferation, migration, and tube formation of endothelial cells. Besides, it directly inhibited VEGFR-2 tyrosine kinase activity and its downstream signaling pathways including MAPK and PI3K/Akt in endothelial cells. Ellagic acid also obviously inhibited neo-vessel formation in chick chorioallantoic membrane and sprouts formation of chicken aorta. Breast cancer xenografts study also revealed that ellagic acid significantly inhibited MDA-MB-231 cancer growth and P-VEGFR2 expression. Molecular docking simulation indicated that ellagic acid could form hydrogen bonds and aromatic interactions within the ATP-binding region of the VEGFR-2 kinase unit. Taken together, ellagic acid could exert anti-angiogenesis effects via VEGFR-2 signaling pathway in breast cancer.

Integrin α(5) interacts with EGFR, is necessary for FcɛRI signaling and is necessary for allergic inflammation in relation with angiogenesis

Recent reports have suggested role for epidermal growth factor receptor (EGFR) in asthma and skin inflammation. Integrin(s) are known to be necessary for the transactivation of EGFR. The roles of EGFR and integrin(s) in allergic inflammation were investigated. Antigen stimulation induced activation of EGFR and interaction between EGFR and integrin α(5) in Rat Basophilic Leukemia (RBL2H3) cells and bone marrow-derived mouse mast cells (BMMCs). Flow cytometry revealed increased phosphorylation of EGFR on cell surfaces. Antigen stimulation induced interaction between EGFR and FcɛRI in both RBL2H3 cells and BMMCs. Blocking of EGFR or integrin α exerted negative effects on rac1 activity and secretion of β-hexosaminidase in both RBL2H3 cells and BMMCs. EGFR and integrin α(5) were found to be necessary for IgE-dependent cutaneous anaphylaxis. FAK (focal adhesion kinase), interacted with EGFR and with FcɛRI upon antigen stimulation, and it was necessary for the increased secretion of β-hexosaminidase in both RBL2H3 cells and BMMCs. EGFR and integrin α(5) were necessary for interactions between activated RBL2H3 cells, BMMCs and rat aortic endothelial cells (RAECs). Conditioned medium of antigen-stimulated RBL2H3 cells promoted RAECs tube formation, rat aortic ring formation and blood vessel formation. Conditioned medium of antigen-stimulated BMMCs also had the same effects on RAECs. This enhanced angiogenic potential of RAECs was dependent on EGFR and integrin α(5). In conclusion, EGFR, via interaction with FcɛRI and integrin α(5), is necessary for allergic inflammation associated with cellular interaction.

N-benzyl-5-phenyl-1H-pyrazole-3-carboxamide promotes vascular endothelial cell angiogenesis and migration in the absence of serum and FGF-2

AIM

To investigate the effect of N-benzyl-5-phenyl-1H-pyrazole-3-carboxamide (BPC) on angiogenesis in human umbilical vein endothelial cells (HUVECs).

METHODS

Capillary-like tube formation on matrigel and cell migration analyses were performed in the absence of serum and fibroblast growth factor (FGF-2). Reactive oxygen species (ROS) were measured using a fluorescent probe, 2', 7'- dichlorodihydrofluorescein (DCHF). The nitric oxide (NO) production of HUVECs was examined using a NO detection kit. Morphological observation under a phase contrast microscope, a viability assay using 3-[4, 5-dimethylthiazol-2-yl]-2, 5-diphenyl-tetrazolium (MTT) and a lactate dehydrogenase (LDH) activity analysis by a detection kit were performed to evaluate the toxicity of BPC on HUVECs in the presence of serum and FGF-2. The level of hypoxia-inducible factor 1α (HIF-1α) and the release of vascular endothelial growth factor (VEGF) were measured by Western blot and ELISA, respectively.

RESULTS

In the absence of serum and FGF-2, cells treated with BPC (5-20 μmol/L) rapidly aligned with one another and formed tube-like structures within 12 h. In the presence of serum and FGF-2, cells treated with BPC for 24, 48 and 72 h had no changes in morphology, viability or LDH release compared with the control group. Cell migration in the BPC-treated group was significantly increased compared with the control group. During this process, NO production and ROS level were elevated dramatically, and the levels of HIF-1α and VEGF were increased dependent on the generation of ROS.

CONCLUSION

BPC most effectively promoted angiogenesis and migration in HUVECs in the absence of FGF-2 and serum.