Systemic and strict regulation of the glutathione redox state in mitochondria and cytosol is needed for zebrafish ontogeny

BACKGROUND

Redox control seems to be indispensable for proper embryonic development. The ratio between glutathione (GSH) and its oxidized disulfide (GSSG) is the most abundant cellular redox circuit.

METHODS

We used zebrafish harboring the glutaredoxin 1-redox sensitive green fluorescent protein (Grx1-roGFP) probe either in mitochondria or cytosol to test the hypothesis that the GSH:GSSG ratio is strictly regulated through zebrafish embryogenesis to sustain the different developmental processes of the embryo.

RESULTS

Following the GSSG:GSH ratio as a proxy for the GSH-dependent reduction potential (EhGSH) revealed increasing mitochondrial and cytosolic EhGSH during cleavage and gastrulation. During organogenesis, cytosolic EhGSH decreased, while that of mitochondria remained high. The similarity between EhGSH in brain and muscle suggests a central regulation. Modulation of GSH metabolism had only modest effects on the GSSG:GSH ratios of newly hatched larvae. However, inhibition of GSH reductase directly after fertilization led to dead embryos already 10 h later. Exposure to the emerging environmental pollutant Perfluorooctane Sulfonate (PFOS) disturbed the apparent regulated EhGSH as well.

CONCLUSIONS

Mitochondrial and cytosolic GSSG:GSH ratios are almost identical in different organs during zebrafish development indicating that the EhGSH might follow H2O2 levels and rather indirectly affect specific enzymatic activities needed for proper embryogenesis.

GENERAL SIGNIFICANCE

Our data confirm that vertebrate embryogenesis depends on strictly regulated redox homeostasis. Disturbance of the GSSG:GSH circuit, e.g. induced by environmental pollution, leads to malformation and death.

PD protects Müller cells through the SIRT1/NLRP3 inflammasome pathway

PURPOSE

Polydatin (PD) has widely pharmacological activities. However, the effects of PD on high glucose (HG)-induced Müller cells in diabetic retinopathy (DR) are rarely studied.

METHODS

The protective effects of PD were evaluated in HG-induced human retinal Müller cells. The levels of pro-angiogenic factors and pro-inflammatory factors were detected using the ELISA kits. The expressions of nucleotide-binding oligomerization domain-like receptor family pyrin domain-containing-3 (NLRP3) and sirtuin-1 (SIRT1) were determined by western blot.

RESULTS

PD inhibited proliferation and activation of HG-induced MIO-M1 cells. PD treatment reduced the levels of pro-angiogenic factors, pro-inflammatory factors, and oxidative stress, while these effects were attenuated by NLRP3 agonist ATP in HG-induced MIO-M1 cells. Furthermore, PD inhibited the activation of NLRP3 inflammasome by regulating the SIRT1 expression after HG stimulation, and knockdown of SIRT1 reversed the inhibition effects of PD on NLRP3 inflammasome, pro-angiogenic factors, pro-inflammatory factors, and oxidative stress in HG-induced MIO-M1 cells.

CONCLUSION

PD may inhibit HG-induced Müller cells proliferation and activation and suppress pro-angiogenic factors, pro-inflammatory factors, and oxidative stress through the SIRT1/NLRP3 inflammasome pathway. In summary, PD treatment may be an effective therapeutic strategy for DR.

Preclinical toxicological assessment of polydatin in zebrafish model

Polydatin (3,4',5-trihydroxystilbene-3-β-D-glucoside, piceid), a natural stilbenoid found in different plant sources, has gained increasing attention for its potential health benefits. However, prior to its widespread adoption in human therapeutics and consumer products, a comprehensive investigation of its toxicological effects is crucial. In this study, the toxicity of polydatin was investigated in a developmental toxicity test using zebrafish (Danio rerio) as a valuable model for preclinical assessments. We employed the Fish Embryo Test (FET test - OECD n°236) to investigate the effects of polydatin on survival, hatchability, development, and behavior of zebrafish embryo-larval stage. Remarkably, the results demonstrated that polydatin up to 435 μM showed no toxicity. Throughout the exposure period, zebrafish embryos exposed to polydatin exhibited normal development, with no significant mortality observed. Furthermore, hatching success and heartbeat rate were unaffected, and no morphological abnormalities were identified, signifying a lack of teratogenic effects and cardiotoxicity. Locomotion activity assessment revealed normal swimming patterns and response to stimuli, indicating no neurotoxic effects. Our study provides valuable insights into the toxicological profile of polydatin, suggesting that it may offer potential therapeutic benefits under a considerable concentration range. In addition, zebrafish model proves to be an efficient system for early-stage toxicological screening, guiding further investigations into the secure utilization of polydatin for human health and wellness.

Advances for pharmacological activities of Polygonum cuspidatum - A review

CONTEXT

Polygonum cuspidatum Sieb. et Zucc (Polygonaceae), the root of which is included in the Chinese Pharmcopoeia under the name 'Huzhang', has a long history as a medicinal plant and vegetable. Polygonum cuspidatum has been used in traditional Chinese medicine for the treatment of inflammation, hyperlipemia, etc.

OBJECTIVE

This article reviews the pharmacological action and the clinical applications of Polygonum cuspidatum and its extracts, whether in vivo or in vitro. We also summarized the main phytochemical constituents and pharmacokinetics of Polygonum cuspidatum and its extracts.

METHODS

The data were retrieved from major medical databases, such as CNKI, PubMed, and SinoMed, from 2014 to 2022. Polygonum cuspidatum, pharmacology, toxicity, clinical application, and pharmacokinetics were used as keywords.

RESULTS

The rhizomes, leaves, and flowers of Polygonum cuspidatum have different phytochemical constituents. The plant contains flavonoids, anthraquinones, and stilbenes. Polygonum cuspidatum and the extracts have anti-inflammatory, antioxidation, anticancer, heart protection, and other pharmacological effects. It is used in the clinics to treat dizziness, headaches, traumatic injuries, and water and fire burns.

CONCLUSIONS

Polygonum cuspidatum has the potential to treat many diseases, such as arthritis, ulcerative colitis, asthma, and cardiac hypertrophy. It has a broad range of medicinal applications, but mainly focused on root medication; its aerial parts should receive more attention. Pharmacokinetics also need to be further investigated.

The neurotrophic activities of brain-derived neurotrophic factor are potentiated by binding with apigenin, a common flavone in vegetables, in stimulating the receptor signaling

AIMS

We aimed to identify the neurotrophic activities of apigenin (4',5,7-trihydroxyflavone) via its coordination with brain-derived neurotrophic factor (BNDF) and an elevated signaling of tyrosine kinase receptor B (Trk B receptor).

METHODS

The direct binding of apigenin to BDNF was validated by ultrafiltration and biacore assay. Neurogenesis, triggered by apigenin and/or BDNF, was determined in cultured SH-SY5Y cells and rat cortical neurons. The amyloid-beta (Aβ)25-35 -induced cellular stress was revealed by propidium iodide staining, mitochondrial membrane potential, bioenergetic analysis, and formation of reactive oxygen species levels. Activation of Trk B signaling was tested by western blotting.

RESULTS

Apigenin and BDNF synergistically maintained the cell viability and promoted neurite outgrowth of cultured neurons. In addition, the BDNF-induced neurogenesis of cultured neurons was markedly potentiated by applied apigenin, including the induced expressions of neurofilaments, PSD-95 and synaptotagmin. Moreover, the synergy of apigenin and BDNF alleviated the (Aβ)25-35 -induced cytotoxicity and mitochondrial dysfunction. The synergy could be accounted by phosphorylation of Trk B receptor, and which was fully blocked by a Trk inhibitor K252a.

CONCLUSION

Apigenin potentiates the neurotrophic activities of BDNF through direct binding, which may serve as a possible treatment for its curative efficiency in neurodegenerative diseases and depression.

The extract of Curcumae Longae Rhizoma suppresses angiogenesis via VEGF-induced PI3K/Akt-eNOS-NO pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Curcumae Longae Rhizoma (CLR) is a safe natural herbal medicine, and which has been widely used for centuries as functional food and health products, but its effects on angiogenesis and related underlying mechanism remain unclear.

AIM OF THE STUDY

The abnormal angiogenesis is closely related with various diseases, and therefore the precise control of angiogenesis is of great importance. The well-known angiogenic factor, vascular endothelial growth factor (VEGF), mediates angiogenesis and induces multiple signalling pathways via binding to VEGF receptor (VEGFR). The attenuation of VEGF-triggered angiogenic-related signalling pathways may relieve various diseases through suppression of angiogenesis. Here, we aimed to elucidate that CLR extract could exert striking anti-angiogenic activities both in vitro and in vivo.

MATERIALS AND METHODS

The viability of human umbilical vascular endothelial cell (HUVEC) was examined by LDH and MTT assays. Migrative and invasive ability of the endothelial cells were independently evaluated by wound healing and transwell assays. The activities of CLR extract on in vitro angiogenesis was tested by tube formation assay. In vivo vascularization was determined by using zebrafish embryo model in the present of CLR extract. Western blotting was applied to determine the phosphorylated levels of VEGFR2, PI3K, AKT and eNOS. Besides, the levels of nitric oxide (NO) and reactive oxygen species (ROS) were separately evaluated by Griess assay and 2'7'-dichlorofluorescein diacetate reaction. In addition, the cell migrative ability of cancer cell was estimated by using cultured human colon carcinoma cells (HT-29 cell line), and immunofluorescence assay was applied to evaluate the effect of CLR extract on nuclear translocation of NF-κB p65 subunit in the VEGF-treated HT-29 cultures.

RESULTS

CLR extract significantly suppressed a series of VEGF-mediated angiogenic responses, including endothelial cell proliferation, migration, invasion, and tube formation. Moreover, CLR extract reduced in vivo sub-intestinal vessel formation in zebrafish embryo model. Mechanistically, the extract of CLR attenuated the VEGF-triggered signalling, as demonstrated by decreased level of phosphorylated VEGFR2 and subsequently inactivated its downstream regulators, e.g. phospho-PI3K, phospho-AKT and phospho-eNOS. The production of NO and formation of ROS were markedly inhibited in HUVECs. Furthermore, CLR extract suppressed cell migration and NF-κB translocation in cultured HT-29 cells.

CONCLUSIONS

These preclinical findings demonstrate that the extract of CLR remarkably attenuates angiogenesis and which has great potential as a natural drug candidate with excellent anti-angiogenic activity.

Resveratrol, an Inhibitor Binding to VEGF, Restores the Pathology of Abnormal Angiogenesis in Retinopathy of Prematurity (ROP) in Mice: Application by Intravitreal and Topical Instillation

Retinopathy of prematurity (ROP) is a severe eye disease leading to blindness. Abnormal vessel formation is the pathological hallmark of neovascular ROP. In forming vessels, vascular endothelial growth factor (VEGF) is an important stimulator. The current anti-ROP therapy has focused on bevacizumab, a monoclonal antibody against VEGF, and pazopanib, a tyrosine kinase inhibitor on the VEGF receptor (VEGFR). Several lines of evidence have proposed that natural compounds may be more effective and safer for anti-VEGF function. Resveratrol, a common natural compound, binds to VEGF and blocks its interaction with VEGFR, thereafter suppressing angiogenesis. Here, we evaluate the efficacy of intravitreal injection, or topical instillation (eye drops), of resveratrol into the eyes of mice suffering from oxygen-induced retinopathy, i.e., developing ROP. The treatment of resveratrol significantly relieved the degree of vascular distortion, permeability and hyperplasia; the efficacy could be revealed by both methods of resveratrol application. In parallel, the treatments of resveratrol inhibited the retinal expressions of VEGF, VEGFR and CD31. Moreover, the applied resveratrol significantly relieved the damage caused by oxygen radicals through upregulating the level of superoxide dismutase (SOD) and downregulating the level of malondialdehyde (MDA) in the retina. Taken together, the potential therapeutic benefit of resveratrol in pro-angiogenic diseases, including retinopathy, can be considered.

A novel long-term intravenous combined with local treatment with human amnion-derived mesenchymal stem cells for a multidisciplinary rescued uremic calciphylaxis patient and the underlying mechanism

Calciphylaxis is a rare disease characterized histologically by microvessel calcification and microthrombosis, with high mortality and no proven therapy. Here, we reported a severe uremic calciphylaxis patient with progressive skin ischemia, large areas of painful malodorous ulcers, and mummified legs. Because of the worsening symptoms and signs refractory to conventional therapies, treatment with human amnion-derived mesenchymal stem cells (hAMSCs) was approved. Pre-clinical release inspections of hAMSCs, efficacy, and safety assessment including cytokine secretory ability, immunocompetence, tumorigenicity, and genetics analysis in vitro were introduced. We further performed acute and long-term hAMSC toxicity evaluations in C57BL/6 mice and rats, abnormal immune response tests in C57BL/6 mice, and tumorigenicity tests in neonatal Balbc-nu nude mice. After the pre-clinical research, the patient was treated with hAMSCs by intravenous and local intramuscular injection and external supernatant application to the ulcers. When followed up to 15 months, the blood-based markers of bone and mineral metabolism improved, with skin soft tissue regeneration and a more favorable profile of peripheral blood mononuclear cells. Skin biopsy after 1-month treatment showed vascular regeneration with mature non-calcified vessels within the dermis, and 20 months later, the re-epithelialization restored the integrity of the damaged site. No infusion or local treatment-related adverse events occurred. Thus, this novel long-term intravenous combined with local treatment with hAMSCs warrants further investigation as a potential regenerative treatment for uremic calciphylaxis with effects of inhibiting vascular calcification, stimulating angiogenesis and myogenesis, anti-inflammatory and immune modulation, multi-differentiation, re-epithelialization, and restoration of integrity.

Guanxinkang Decoction Attenuates the Inflammation in Atherosclerosis by Regulating Efferocytosis and MAPKs Signaling Pathway in LDLR-/- Mice and RAW264.7 Cells

Guanxinkang decoction (GXK), a traditional Chinese medicinal drug, is used to treat cardiovascular disease. The aim of the study was to investigate the effects of GXK on inflammation in LDLR^−/− mice and RAW264.7 cells. Fed with high fat diet for 12 weeks, the mice were randomly divided into six groups, then administered with oral 0.9% saline or GXK (7.24, 14.48, and 28.96 g/kg) or Atorvastatin (1.3 mg/kg) for 12 weeks. RAW 264.7 cells were induced with ox-LDL or ox-LDL plus different concentrations of GXK (1.25, 2.5, and 5 μg/ml), or ox-LDL plus GXK plus MAPKs activators. Serum lipid profiles and inflammatory cytokines were detected by ELISA, gene expression by RT-qPCR, plaque sizes by Oil Red O, α-SMA, caspase 3, NF-κB p65 and TNF-α production by immunofluorescence staining, and protein expression by Western Blot. The phagocytic ability of cells was determined by neutral red uptake assay. Efferocytosis-related proteins (AML, MERTK, TYRO3 and MFGE8) and MAPKs pathways were detected by Western Blot. Compared to mice fed with high fat diet, the mice with GXK showed lower cholesterol, triglyceride, low-density lipoprotein cholesterol, IL-1β, IL-6, and TNF-α, smaller plaque sizes, higher α-SMA, and lower caspase 3 and NF-κB p65 in aortic roots. RAW264.7 cells treated with ox-LDL plus GXK had lower IL-1β, IL-6, and TNF-α. GXK also increased the phagocytic ability of cells. High levels of AML, MERTK, TYRO3 and MFGE8, and decreased levels of iNOS, VCAM-1, LOX-1 and MCP-1, and phosphorylation of ERK1/2, JNK, p38, and NF-κB were detected in GXK-treated group. MAPKs activators reversed the effects of GXK in repressing inflammation and promoting phagocytosis. These results suggested that GXK could attenuate atherosclerosis and resolve inflammation via efferocytosis and MAPKs signaling pathways in LDLR^−/− mice and RAW264.7 cells.

Old dog, new tricks: Polydatin as a multitarget agent for current diseases

Polydatin (PD) is a natural single-crystal product that is primarily extracted from the traditional plant Polygonum cuspidatum Sieb. et Zucc. Early research showed that PD exhibited a variety of biological activities. PD has attracted increasing research interest since 2014, but no review comprehensively summarized the new findings. A great gap between its biological activities and drug development remains. It is necessary to summarize new findings on the pharmacological effects of PD on current diseases. We propose that PD will most likely be used in cardiac and cerebral ischaemia/reperfusion-related diseases and atherosclerosis in the future. The present work classified these new findings according to diseases and summarized the main effects of PD via specific mechanisms of action. In summary, we found that PD played a therapeutic role in a variety of diseases, primarily via five mechanisms: antioxidative effects, antiinflammatory effects, regulation of autophagy and apoptosis, maintenance of mitochondrial function, and lipid regulation.

Gambogic amide inhibits angiogenesis by suppressing VEGF/VEGFR2 in endothelial cells in a TrkA-independent manner

CONTEXT

Gambogic amide (GA-amide) is a non-peptide molecule that has high affinity for tropomyosin receptor kinase A (TrkA) and possesses robust neurotrophic activity, but its effect on angiogenesis is unclear.

OBJECTIVE

The study investigates the antiangiogenic effect of GA-amide on endothelial cells (ECs).

MATERIALS AND METHODS

The viability of endothelial cells (ECs) treated with 0.1, 0.15, 0.2, 0.3, 0.4, and 0.5 μM GA-amide for 48 h was detected by MTS assay. Wound healing and angiogenesis assays were performed on cells treated with 0.2 μM GA-amide. Chicken eggs at day 7 post-fertilization were divided into the dimethyl sulfoxide (DMSO), bevacizumab (40 μg), and GA-amide (18.8 and 62.8 ng) groups to assess the antiangiogenic effect for 3 days. mRNA and protein expression in cells treated with 0.1, 0.2, 0.4, 0.8, and 1.2 μM GA-amide for 6 h was detected by qRT-PCR and Western blots, respectively.

RESULTS

GA-amide inhibited HUVEC (IC₅₀ = 0.1269 μM) and NhEC (IC₅₀ = 0.1740 μM) proliferation, induced cell apoptosis, and inhibited the migration and angiogenesis at a relatively safe dose (0.2 μM) in vitro. GA-amide reduced the number of capillaries from 56 ± 14.67 (DMSO) to 20.3 ± 5.12 (62.8 ng) in chick chorioallantoic membrane (CAM) assay. However, inactivation of TrkA couldn't reverse the antiangiogenic effect of GA-amide. Moreover, GA-amide suppressed the expression of VEGF and VEGFR2, and decreased activation of the AKT/mTOR and PLCγ/Erk1/2 pathways.

CONCLUSIONS

Considering the antiangiogenic effect of GA-amide, it might be developed as a useful agent for use in clinical combination therapies.

Resveratrol Attenuates Meningitic Escherichia coli-Mediated Blood-Brain Barrier Disruption

Meningitic Escherichia coli can infiltrate the central nervous system (CNS), consequently increasing the levels of proinflammatory cytokines and chemokines and deteriorating the integrity of the blood-brain barrier (BBB). Resveratrol has emerged in recent years as a compound with antioxidant and anti-inflammatory properties. However, it is still unknown how resveratrol affects meningitic E. coli-induced CNS dysfunction. Here, by using in vivo and in vitro BBB models, we demonstrated that resveratrol treatment significantly inhibited meningitic E. coli invasion of the BBB, protected the integrity of the BBB, and reduced neuroinflammation and lethality. In mechanism, resveratrol inhibited bacterial penetration of the BBB by attenuating the upregulation of caveolin-1 (CAV-1), a class of lipid rafts maintaining endothelial cell function. Resveratrol treatment also maintained BBB permeability by suppressing the ERK1/2-VEGFA signaling cascade. In vivo treatment of resveratrol decreased the production of inflammatory cytokines and improved the survival rate in mice challenged with meningitic E. coli. These findings collectively indicated that resveratrol could attenuate meningitic E. coli-induced CNS injury, which might constitute a new approach for future prevention and treatment of E. coli meningitis.

Efficacy of Conversion Surgery Following Apatinib Plus Paclitaxel/S1 for Advanced Gastric Cancer With Unresectable Factors: A Multicenter, Single-Arm, Phase II Trial

Objective: Conversion therapy (surgical resection after chemotherapy) is a promising option for unresectable gastric cancer (GC) patients. Addition of anti-angiogenesis drug improves response to chemotherapy. Hence, this study explored the feasibility and efficacy of preoperative paclitaxel (PTX)/S1 chemotherapy combined with apatinib for unresectable GC. Methods: Thirty-one eligible patients with a single unresectable factor were enrolled in this multi-center, single-arm trial. Apatinib (500 mg qd) was administered continuously, while PTX (130 mg/m²) on day 1 and S1 (80 mg/m²) on day 1-14 were given every 3 weeks. The treatment was given for three cycles preoperatively, but the last cycle did not include apatinib. The primary objective measurements included R0 resection rate, objective response rate (ORR) and morbidity of preoperative treatment. Results: Among the 31 patients, 30 patients were evaluable for tumor response, the ORR to preoperative treatment was 73.3%. Eighteen of 30 patients underwent surgery, and R0 resection was achieved in 17 patients. The patients who underwent the conversion surgery had a superior OS compared with those who did not (3 years OS: 52.9 vs 8.3%, p = 0.001). The surgery was operated after apatinib had stopped for a median duration of 4 weeks. Neither anastomotic leakage nor wound healing complications was observed. No increased bleeding event was observed compared with historical data. During preoperative treatment, grade 3 or 4 toxicities were experienced by 58.1% of the patients. Conclusion: Chemotherapy in combination with apatinib demonstrated higher rates of conversion and R0 resection and a superior survival benefit in initial unresectable GC. It is safe and reasonable to suspend apatinib for 4 weeks before the gastrectomy.

An Optimized Extract, Named Self-Growth Colony, from Platelet-Rich Plasma Shows Robust Skin Rejuvenation and Anti-Ageing Properties: A Novel Technology in Development of Cosmetics

INTRODUCTION

Inspired by application of platelet-rich plasma (PRP) in skin treatment during injuries, an extracting method was developed here to recover high amounts of cytokines and growth factors from PRP; this prepared extract was named as self-growth colony (SGC).

METHODS

In optimization of SGC preparation, various parameters were tested, for example, centrifugation force, freeze-thaw, sonication, and inclusion of calcium chelator. The amounts of cytokines and growth factors, including platelet factor 4, β-thromboglobulin, epidermal growth factor, vascular endothelial growth factor, platelet-derived growth factor, were measured by ELISA assay.

RESULTS

By comparing to PRP, the prepared SGC contained a significant higher amount of measured growth factors. In addition, the degradation of growth factors within SGC during the storage was calibrated, which showed better stability as compared to that of PRP preparation. Having possible application in skin care, the optimized SGC was chemically standardized by using the enrichment of growth factors. Application of SGC in cultured keratinocytes stimulated the wound healing of injured cultures. In line to this notion, SGC was applied onto human skin, and thereafter the robust improvement of skin properties was revealed.

CONCLUSIONS

The potential application of SGC in treating skin rejuvenation and ageing, as well as its elaborated application for medical purpose, that is, wound healing, was illustrated.

The binding of kaempferol-3-O-rutinoside to vascular endothelial growth factor potentiates anti-inflammatory efficiencies in lipopolysaccharide-treated mouse macrophage RAW264.7 cells

BACKGROUND

Vascular Endothelial Growth Factors (VEGFs) are a group of growth factor in regulating development and maintenance of blood capillary. The VEGF family members include VEGF-A, placenta growth factor (PGF), VEGF-B, VEGF-C and VEGF-D. VEGF receptor activation leads to multiple complex signaling pathways, particularly in inducing angiogenesis. Besides, VEGF is produced by macrophages and T cells, which is playing roles in inflammation. In macrophages, VEGF receptor-3 (VEGFR-3) and its ligand VEGF-C are known to attenuate the release of pro-inflammatory cytokines.

METHODS

Immunoprecipitation and molecular docking assays showed the binding interaction of kaempferol-3-O-rutinoside and VEGF-C. Western blotting and qRT-PCR methods were applied to explore the potentiating effect of kaempferol-3-O-rutinoside in VEGF-C-mediated expressions of proteins and genes in endothelial cells and LPS-induced macrophages. Enzyme-linked immunosorbent assay (ELISA) was employed to reveal the release of proinflammatory cytokines in LPS-induced macrophages. Immunofluorescence assay was performed to determine the effect of kaempferol-3-O-rutinoside in regulating nuclear translocation of NF-κB p65 subunit in the VEGF-C-treated cultures. In addition, Transwell® motility assay was applied to detect the ability of cell migration after drug treatment in LPS-induced macrophages.

RESULTS

We identified kaempferol-3-O-rutinoside, a flavonoid commonly found in vegetable and fruit, was able to act on cultured macrophages in inhibiting inflammatory response, and the inhibition was mediated by its specific binding to VEGF-C. The kaempferol-3-O-rutinoside-bound VEGF-C showed high potency to trigger the receptor activation. In LPS-treated cultured macrophages, applied kaempferol-3-O-rutinoside potentiated inhibitory effects of exogenous applied VEGF-C on the secretions of pro-inflammatory cytokines, i.e. IL-6 and TNF-α, as well as expressions of nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2). This inhibition was in parallel to transcription and translocation of NF-κB. Moreover, the binding of kaempferol-3-O-rutinoside with VEGF-C suppressed the LPS-induced migration of macrophage.

CONCLUSION

Taken together, our results suggested the pharmacological roles of kaempferol-3-O-rutinoside in VEGF-C-mediated anti-inflammation.

Piceatannol, a Natural Analog of Resveratrol, Exerts Anti-angiogenic Efficiencies by Blockage of Vascular Endothelial Growth Factor Binding to Its Receptor

Piceatannol is also named as trans-3,4,3′,5′-tetrahydroxy-stilbene, which is a natural analog of resveratrol and a polyphenol existing in red wine, grape and sugar cane. Piceatannol has been proved to possess activities of immunomodulatory, anti-inflammatory, antiproliferative and anticancer. However, the effect of piceatannol on VEGF-mediated angiogenesis is not known. Here, the inhibitory effects of piceatannol on VEGF-induced angiogenesis were tested both in vitro and in vivo models of angiogenesis. In human umbilical vein endothelial cells (HUVECs), piceatannol markedly reduced the VEGF-induced cell proliferation, migration, invasion, as well as tube formation without affecting cell viability. Furthermore, piceatannol significantly inhibited the formation of subintestinal vessel in zebrafish embryos in vivo. In addition, we identified the underlying mechanism of piceatannol in triggering the anti-angiogenic functions. Piceatannol was proposed to bind with VEGF, thus attenuating VEGF in activating VEGF receptor and blocking VEGF-mediated downstream signaling, including expressions of phosphorylated eNOS, Erk and Akt. Furthermore, piceatannol visibly suppressed ROS formation, as triggered by VEGF. Moreover, we further determined the outcome of piceatannol binding to VEGF in cancer cells: piceatannol significantly suppressed VEGF-induced colon cancer proliferation and migration. Thus, these lines of evidence supported the conclusion that piceatannol could down regulate the VEGF-mediated angiogenic functions with no cytotoxicity via decreasing the amount of VEGF binding to its receptors, thus affecting the related downstream signaling. Piceatannol may be developed into therapeutic agents or health products to reduce the high incidence of angiogenesis-related diseases.

Ligamentum flavum fibrosis and hypertrophy: Molecular pathways, cellular mechanisms, and future directions

Hypertrophy of ligamentum flavum (LF), along with disk protrusion and facet joints degeneration, is associated with the development of lumbar spinal canal stenosis (LSCS). Of note, LF hypertrophy is deemed as an important cause of LSCS. Histologically, fibrosis is proved to be the main pathology of LF hypertrophy. Despite the numerous studies explored the mechanisms of LF fibrosis at the molecular and cellular levels, the exact mechanism remains unknown. It is suggested that pathophysiologic stimuli such as mechanical stress, aging, obesity, and some diseases are the causative factors. Then, many cytokines and growth factors secreted by LF cells and its surrounding tissues play different roles in activating the fibrotic response. Here, we summarize the current status of detailed knowledge available regarding the causative factors, pathology, molecular and cellular mechanisms implicated in LF fibrosis and hypertrophy, also focusing on the possible avenues for anti-fibrotic strategies.

High-throughput screening suggests glutathione synthetase as an anti-tumor target of polydatin using human proteome chip

Polydatin (PD) is a bio-active ingredient with known anti-tumor effects. However, its specific protein targets yet have not been systematically screened, and the molecular anti-tumor mechanism is still unclear. Here, proteomic-chip was efficiently used to screen potential targets of PD. First, we investigated through animal experiment and proteomics studies, and found that polydatin play an important role in tumor cells. Then, the red-green fluorescent of polydatin was compared comprehensively to screen its targets on chip, followed by bioinformatics analysis. Glutathione synthetase (GSS) was selected as candidate research target. After a series of molecular biological experiments GSS was confirmed a target protein for PD in vitro. Moreover, we also found that PD can significantly inhibit the activity of GSS in vitro and live cells. Our findings reveal that PD could be a selective small-molecule GSS enzyme activity inhibitor and GSS could be a potential therapeutic target in cancer.

Kaempferol, a Major Flavonoid in Ginkgo Folium, Potentiates Angiogenic Functions in Cultured Endothelial Cells by Binding to Vascular Endothelial Growth Factor

Kaempferol is a major flavonoid in Ginkgo Folium and other edible plants, which is being proposed here to have roles in angiogenesis. Angiogenesis is important in both physiological and pathological development. Here, kaempferol was shown to bind with vascular endothelial growth factor (VEGF), probably in the heparin binding domain of VEGF: this binding potentiated the angiogenic functions of VEGF in various culture models. Kaempferol potentiated the VEGF-induced cell motility in human umbilical vein endothelial cells (HUVECs), as well as the sub-intestinal vessel sprouting in zebrafish embryos and formation of microvascular in rat aortic ring. In cultured HUVECs, application of kaempferol strongly potentiated the VEGF-induced phosphorylations of VEGFR2, endothelial nitric oxide synthase (eNOS) and extracellular signal-regulated kinase (Erk) in time-dependent and concentration-dependent manners, and in parallel the VEGF-mediated expressions of matrix metalloproteinases (MMPs), MMP-2 and MMP-9, were significantly enhanced. In addition, the potentiation effect of kaempferol was revealed in VEGF-induced migration of skin cell and monocyte. Taken together, our results suggested the pharmacological roles of kaempferol in potentiating VEGF-mediated functions should be considered.

Nanodrug with ROS and pH Dual-Sensitivity Ameliorates Liver Fibrosis via Multicellular Regulation

Liver fibrosis currently represents a global health problem without effective pharmacotherapeutic strategies. The clinical translation of polydatin, a promising natural anti-fibrotic drug candidate with broad anti-inflammatory and antioxidant capabilities, remains a major challenge due to its limited water solubility and tissue absorption. Herein, a polydatin-loaded micelle (PD-MC) based on reactive oxygen species (ROS) and pH dual-sensitive block polymer PEG-P(PBEM-co-DPA) is developed. The micelle exerts great potential in improving the biocompatibility of polydatin and shows highly efficient liver-targeted drug release in response to the fibrotic microenvironment. Both in vitro and in vivo studies demonstrate that PD-MC can significantly suppress inflammatory response and oxidative stress, reduce hepatocyte apoptosis, and avert activation of macrophages and hepatic stellate cells. More excitingly, the blank micelle itself promotes the hepatic ROS consumption at the pathologic site to provide anti-inflammatory benefits. These favorable therapeutic virtues of targeting multiple cell types endow PD-MC with remarkable efficacy with minimal side effects in liver fibrosis treatment. Thus, PD-MC holds great potential to push forward the clinical application of polydatin in pharmacotherapeutic approaches against liver fibrosis.

Synergy of Ginkgetin and Resveratrol in Suppressing VEGF-Induced Angiogenesis: A Therapy in Treating Colorectal Cancer

Ginkgetin, a biflavone from Ginkgo biloba leaf, and resveratrol, a polyphenol found in grape and wine, are two phytochemicals being identified for its binding to vascular endothelial growth factor (VEGF): the binding, therefore, resulted in the alteration of the physiological roles of VEGF-mediated angiogenesis. The bindings of ginkgetin and resveratrol were proposed on different sites of VEGF, but both of them suppressed the angiogenic properties of VEGF. The suppressive activities of ginkgetin and resveratrol in VEGF-mediated angiogenesis were supported by several lines of evidence including (i) inhibiting the formation of sub-intestinal vessel in zebrafish embryos and microvascular sprouting in rat aortic ring; and (ii) suppressing the phosphorylations of VEGFR2, Akt, eNOS, and Erk as well as expressions of matrix metalloproteinases (MMPs), MMP-2, and MMP-9 in human umbilical vein endothelial cells (HUVECs). Here, we showed the synergy of ginkgetin and resveratrol in suppressing the VEGF-induced endothelial cell proliferation, migration, invasion, and tube formation. The synergy of ginkgetin and resveratrol was further illustrated in HT-29 colon cancer xenograft nude mice. Ginkgetin and resveratrol, when applied together, exerted a synergistic anti-tumor effect of 5-fluorouracil with decreasing microvessel density of tumors. In parallel, the combination of ginkgetin and resveratrol synergistically relieved the 5-fluorouracil-induced inflammatory response by suppressing expressions of COX-2 and inflammatory cytokines. Thus, the anti-angiogenic roles of ginkgetin and/or resveratrol could provide effective therapeutic strategy in cancer, similar to that of Avastin, in suppressing the VEGF-mediated angiogenesis during cancer development.

Polydatin Encapsulated Poly [Lactic-co-glycolic acid] Nanoformulation Counteract the 7,12-Dimethylbenz[a] Anthracene Mediated Experimental Carcinogenesis through the Inhibition of Cell Proliferation

In the present study, the authors have attempted to fabricate Polydatin encapsulated Poly [lactic-co-glycolic acid] (POL-PLGA-NPs) to counteract 7,12-dimethyl benzyl anthracene (DMBA) promoted buccal pouch carcinogenesis in experimental animals. The bio-formulated POL-PLGA-NPs were characterized by dynamic light scattering (DLS), Fourier transform infrared (FTIR) spectroscopy, X-ray powder diffraction (XRD) pattern analysis, and transmission electron microscope (TEM). In addition, the nano-chemopreventive potential of POL-PLGA-NPs was assessed by scrutinizing the neoplastic incidence and analyzing the status of lipid peroxidation, antioxidants, phase I, phase II detoxification status, and histopathological changes and in DMBA-treated animals. In golden Syrian hamsters, oral squamous cell carcinoma (OSCC) was generated by painting with 0.5% DMBA in liquid paraffin three times a week for 14 weeks. After 100% tumor formation was observed, high tumor volume, tumor burden, and altered levels of biochemical status were observed in the DMBA-painted hamsters. Intra-gastric administration of varying concentration of POL-PLGA-NPs (7.5, 15, and 30 mg/kg b.wt) to DMBA-treated hamsters assumedly prevents oncological incidences and restores the status of the biochemical markers. It also significantly enhances the apoptotic associated and inhibits the cancer cell proliferative markers expression (p53, Bax, Bcl-2, cleaved caspase 3, cyclin-D1). The present study reveals that POL-PLGA-NPs is a penitential candidate for nano-chemopreventive, anti-lipid peroxidative, and antioxidant potential, and also has a modulating effect on the phase I and Phase II detoxification system, which is associated with reduced cell proliferation and induced apoptosis in experimental oral carcinogenesis.

Binding of Resveratrol to Vascular Endothelial Growth Factor Suppresses Angiogenesis by Inhibiting the Receptor Signaling

Resveratrol is a polyphenol commonly found in plants and food health products, such as grape and red wine, and was identified for its binding to vascular endothelial growth factor (VEGF) by using HerboChips screening. The binding, therefore, resulted in alterations of VEGF binding to its receptor and revealed the roles of VEGF in angiogenesis. Several lines of evidence gave support to the inhibitory activities of resveratrol in VEGF-triggered angiogenesis. In human umbilical vein endothelial cells (HUVECs), compared with a VEGF-induced group, resveratrol, at a high concentration, suppressed VEGF-mediated endothelial cell proliferation, cell migration, cell invasion, and tube formation by 80 ± 9.01%, 140 ± 3.78%, 110 ± 7.51%, and 120 ± 10.26%, respectively. Moreover, resveratrol inhibited the subintestinal vessel formation in zebrafish embryo. In signaling cascades, application of resveratrol in HUVECs reduced the VEGF-triggered VEGF receptor 2 phosphorylation and c-Jun N-terminal kinase phosphorylation. Moreover, the VEGF-mediated phosphorylations of endothelial nitric oxide synthase, protein kinase B, and extracellular signal-regulated kinase were obviously decreased by (3 ± 0.37)-, (2 ± 0.27)- and (6 ± 0.23)-fold, respectively, in the presence of resveratrol at high concentration. Parallelly, the VEGF-induced reactive oxygen species formation was significantly decreased by 50 ± 7.88% to 120 ± 14.82% under resveratrol treatment. Thus, our results provided support to the antiangiogenic roles of resveratrol, as well as its related signaling mechanisms, in attenuating the VEGF-mediated responses. The present results supported possible development of resveratrol, which should be considered as a therapeutic agent in terms of prevention and clinical treatment of diseases related to angiogenesis.

Cardioprotection and improvement in endothelial-dependent vasodilation during late-phase of whole body hypoxic preconditioning in spontaneously hypertensive rats via VEGF and endothelin-1

The present study was designed to investigate the effect of late phase of whole body hypoxic preconditioning on endothelial-dependent vasorelaxation and cardioprotection from ischemia-reperfusion injury in spontaneously hypertensive rats (SHR). Hypoxic preconditioning was performed by subjecting rats to four episodes of alternate exposure to low O₂ (8%) and normal air O₂ of 10 min each. After 24 h, the mesenteric arteries and hearts were isolated to determine the vascular function and cardioprotection from ischemia-reperfusion (I/R) injury on the Langendorff apparatus. There was a significant impairment in acetylcholine-induced relaxation in norepinephrine precontracted arteries (endothelium-dependent function) and increase in I/R-induced myocardial injury in SHR in comparison to Wistar Kyoto rats (WKY). However, hypoxic preconditioning significantly restored endothelium-dependent relaxation in SHR and attenuated I/R injury in both SHR and WKY. Hypoxic preconditioning also led to an increase in the levels of endothelin-1 (not endothelin-2 or -3), vascular endothelial growth factor-A (VEGF-A) and HIF-1α levels. Pretreatment with bevacizumab (anti-VEGF-A) and bosentan (endothelin receptor blocker) significantly attenuated hypoxic preconditioning-induced restoration of endothelium-dependent relaxation and cardioprotection from I/R injury. These interventions also attenuated the levels of VEGF-A and HIF-1α without modulating the endothelin-1 levels. It may be concluded that an increase in the endothelin-1 levels with a subsequent increase in HIF-1α and VEGF expression may possibly contribute in improving endothelium-dependent vasorelaxation and protecting hearts from I/R injury in SHR during late phase of whole body hypoxic preconditioning.