The pyrrolidinoindoline alkaloid Psm2 inhibits platelet aggregation and thrombus formation by affecting PI3K/Akt signaling

Gualou-Xiebai herb pair and its active ingredients act against atherosclerosis by suppressing VSMC-derived foam cell formation via regulating P2RY12-mediated lipophagy

BACKGROUND

Atherosclerosis (AS) is a chronic disease characterized by lipid accumulation in the aortic wall and the formation of foam cells overloaded with large lipids inclusions. Currently, Western medicine is primarily used to improve lipid metabolism disorders and reduce inflammatory reactions to delay AS progression, but these medicines come with serious side effects and drug resistance. Gualou-Xiebai (GLXB) is a renowned herb pair that has been proven effective against AS. However, the potential molecular mechanism through which GLXB exerts the anti-atherosclerotic effects of increasing lipophagy in vascular smooth muscle cells (VSMCs) remains unknown.

PURPOSE

This study aims to explore the role of lipophagy and the therapeutic mechanism of GLXB in AS.

METHODS

UPLC-Q-TOF-MS for the determination of the main components of GLXB-containing serum. An AS mouse model was established by feeding a high-fat diet (HFD) to ApoE-/- mice for 12 weeks. Ultrasonography monitoring was used to confirm the successful establishment of the AS model. Plaque areas and lipid deposition were evaluated using HE staining and aorta imagingafter GLXB treatment. Immunofluorescence staining and Western blotting were utilized to observe the P2RY12 and lipophagy levels in AS mice. VSMCs were stimulated with oxidized low-density lipoprotein (ox-LDL) to induce foam cell formation. The degree of lipophagy and the related molecular mechanisms were assessed after treating the VSMCs with GLXB-containing serum or si-P2RY12 transfection. The active components of GLXB-containing serum that act on P2RY12 were screened and verified by molecular docking and dual-luciferase reporter assays.

RESULTS

Seventeen components of GLXB were identified in rat serum by UPLC-Q-TOF-MS. GLXB significantly reduced lipid deposition in HFD-fed ApoE-/- mice and ox-LDL-induced VSMCs. GLXB strikingly increased lipophagy levels by downregulating P2RY12, p62, and plin2, upregulating LC3Ⅱ protein expression, and increasing the number of autophagosomes. Notably, the lipophagy inhibitor CQ and the P2RY12 receptor agonist ADPβ abolished the GLXB-induced increase in lipophagy. Last, we confirmed that albiflorin, apigenin, luteolin, kaempferol, 7,8-dihydroxyflavone, and hesperetin from GLXB significantly inhibited P2RY12.

CONCLUSION

GLXB activates lipophagy and inhibits lipid accumulation-associated VSMC-derived foam cell formation through suppressing P2RY12 activation, resulting in anti-atherosclerotic effects. The GLXB components albiflorin, apigenin, luteolin, kaempferol, 7,8-dihydroxyflavone, and hesperetin are the potential active effectors against P2RY12.

Therapeutic effects and molecular mechanisms of natural products in thrombosis

Thrombotic disorders, such as myocardial infarction and stroke, are the leading cause of death in the global population and have become a health problem worldwide. Drug therapy is one of the main antithrombotic strategies, but antithrombotic drugs are not completely safe, especially the risk of bleeding at therapeutic doses. Recently, natural products have received widespread interest due to their significant efficacy and high safety, and an increasing number of studies have demonstrated their antithrombotic activity. In this review, articles from databases, such as Web of Science, PubMed, and China National Knowledge Infrastructure, were filtered and the relevant information was extracted according to predefined criteria. As a result, more than 100 natural products with significant antithrombotic activity were identified, including flavonoids, phenylpropanoids, quinones, terpenoids, steroids, and alkaloids. These compounds exert antithrombotic effects by inhibiting platelet activation, suppressing the coagulation cascade, and promoting fibrinolysis. In addition, several natural products also inhibit thrombosis by regulating miRNA expression, anti-inflammatory, and other pathways. This review systematically summarizes the natural products with antithrombotic activity, including their therapeutic effects, mechanisms, and clinical applications, aiming to provide a reference for the development of new antithrombotic drugs.

Marine-Fungus-Derived Natural Compound 4-Hydroxyphenylacetic Acid Induces Autophagy to Exert Antithrombotic Effects in Zebrafish

Marine natural products are important sources of novel drugs. In this study, we isolated 4-hydroxyphenylacetic acid (HPA) from the marine-derived fungus Emericellopsis maritima Y39-2. The antithrombotic activity and mechanism of HPA were reported for the first time. Using a zebrafish model, we found that HPA had a strong antithrombotic activity because it can significantly increase cardiac erythrocytes, blood flow velocity, and heart rate, reduce caudal thrombus, and reverse the inflammatory response caused by Arachidonic Acid (AA). Further transcriptome analysis and qRT-PCR validation demonstrated that HPA may regulate autophagy by inhibiting the PI3K/AKT/mTOR signaling pathway to exert antithrombotic effects.

Deep sequencing of circulating miRNAs and target mRNAs level in deep venous thrombosis patients

Deep venous thrombosis is one of the most common peripheral vascular diseases that lead to major morbidity and mortality. The authors aimed to identify potential differentially expressed miRNAs and target mRNAs, which were helpful in understanding the potential molecule mechanism of deep venous thrombosis. The plasma samples of patients with deep venous thrombosis were obtained for the RNA sequencing. Differentially expressed miRNAs were identified, followed by miRNA-mRNA target analysis. Enrichment analysis was used to analyze the potential biological function of target mRNAs. GSE19151 and GSE173461 datasets were used for expression validation of mRNAs and miRNAs. 131 target mRNAs of 21 differentially expressed miRNAs were identified. Among which, 8 differentially expressed miRNAs including hsa-miR-150-5p, hsa-miR-326, hsa-miR-144-3p, hsa-miR-199a-5p, hsa-miR-199b-5p, hsa-miR-125a-5p, hsa-let-7e-5p and hsa-miR-381-3p and their target mRNAs (PRKCA, SP1, TP53, SLC27A4, PDE1B, EPHB3, IRS1, HIF1A, MTUS1 and ZNF652) were found associated with deep venous thrombosis for the first time. Interestingly, PDE1B and IRS1 had a potential diagnostic value for patients. Additionally, 3 important signaling pathways including p53, PI3K-Akt and MAPK were identified in the enrichment analysis of target mRNAs (TP53, PRKCA and IRS1). Identified circulating miRNAs and target mRNAs and related signaling pathways may be involved in the process of deep venous thrombosis.

The phytoestrogenic potential of flavonoid glycosides from Selaginella moellendorffii via ERα-dependent signaling pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Selaginella moellendorffii (SM) has been applied as an ethnic drug to treat conditions such as osteoporosis, idiopathic thrombocytopenic purpura, and chronic inflammation. It is known to be rich in flavonoids, including apigenin glycosides and unique elements of bioflavonoids.

AIM OF THE STUDY

To investigate estrogen-like constituents of SM and the possible mechanism.

MATERIALS AND METHODS

We identified the main components in liquid chromatography and liquid chromatography-mass spectrometry. The estrogenic effects were examined using a recombinant yeast screening assay, an E-screen cell proliferation assay, and an in vivo uterotrophic assay.

RESULTS

Flavonoid glycosides extract, some flavonoid glycosides, and apigenin showed estrogen agonistic activity in the yeast screening assay. They also induced cell proliferation in estrogen receptor-positive (ER+) cells but not in estrogen receptor-negative (ER-) cells. Consistently, the protein expression of ERα, phosphorylation protein kinase B (p-AKT), phosphatidylinositol 3 kinase (PI3K), phosphorylation mammalian target of rapamycin (p-mTOR), phosphorylation 38,000-Da protein (p-P38), and phosphorylation extracellular-regulated kinase 1/2 (p-ERK1/2) elevated following treatment with flavonoid glycoside extract (P < 0.01 or P < 0.05). These effects could be blocked by ER antagonist or ERα antagonist but not be blocked by ERβ antagonist. In vivo assay, flavonoid glycoside extract could significantly increase body weight, serum estradiol level, uterine wet weight, alter uterine morphology, and promote ERα protein expression (P < 0.01 or P < 0.05).

CONCLUSIONS

ERα induction via mitogen-activated protein kinases (MAPK) and PI3K/Akt/mTOR pathways might be the possible mechanism underlying the phytoestrogen effect of SM, and the flavonoid glycosides might be the critical estrogenic constituents.

Elucidation of Phytochemicals Affecting Platelet Responsiveness in Dangguisu-san: Active Ingredient Prediction and Experimental Research Using Network Pharmacology

Plant-derived phytochemicals are emerging as novel agents for protection against chronic disorders. Dangguisu-san is a herbal prescription to invigorate the blood and relieve pain. Among the numerous active constituents of Dangguisu-san, those expected to be effective at inhibiting platelet aggregation were predicted using a network pharmacological method, and their efficacy was experimentally demonstrated. All four identified chemical components, namely chrysoeriol, apigenin, luteolin, and sappanchalcone, suppressed the aggregation of platelets to a certain extent. However, we report, for the first time, that chrysoeriol acts as a strong inhibitor of platelet aggregation. Although additional in vivo studies are needed, among the complex constituents of herbal medicines, the components that exert an inhibitory effect on platelet aggregation were predicted using a network pharmacological method and experimentally confirmed with human platelets.

Mechanism of platelet activation and potential therapeutic effects of natural drugs

BACKGROUND

Cardiovascular disease is one of the most concerning chronic diseases in the world. Many studies have shown that platelet overactivation is a very important factor in the occurrence and development of cardiovascular diseases. At present, the widely used antiplatelet drugs have some defects, such as drug resistance and adverse reactions.

PURPOSE

The purpose of this article is to summarize the main mechanisms and pathways of platelet activation, the main targets of antiplatelet aggregation, and the antiplatelet aggregation components of natural drugs and their mechanisms of action to provide new research ideas for the development and application of antiplatelet drugs.

STUDY DESIGN AND METHODS

In this review, we systematically searched the PubMed, Google Scholar, Web of Science, and CNKI databases and selected studies based on predefined eligibility criteria. We then assessed their quality and extracted data.

RESULTS

ADP, AA, THR, AF, collagen, SDF-1α, and Ca²⁺ can induce platelet aggregation and trigger thrombosis. Natural drugs have a good inhibitory effect on platelet activation. More than 50 kinds of natural drugs and over 120 kinds of chemical compounds, including flavonoids, alkaloids, saponins, terpenoids, coumarins, and organic acids, have significantly inhibited platelet activation activity. The MAPK pathway, cGMP-PKG pathway, cAMP-PKA pathway, PI3K-AKT pathway, PTK pathway, PLC pathway, and AA pathway are the main mechanisms and pathways of platelet activation.

CONCLUSION

Natural drugs and their active ingredients have shown good activity and application prospects in anti-platelet aggregation. We hope that this review provides new research ideas for the development and application of antiplatelet drugs.

Insights into potential mechanisms of asthma patients with COVID-19: A study based on the gene expression profiling of bronchoalveolar lavage fluid

Background

The 2019 novel coronavirus disease (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is currently a major challenge threatening the global healthcare system. Respiratory virus infection is the most common cause of asthma attacks, and thus COVID-19 may contribute to an increase in asthma exacerbations. However, the mechanisms of COVID-19/asthma comorbidity remain unclear.

Methods

The “Limma” package or “DESeq2” package was used to screen differentially expressed genes (DEGs). Alveolar lavage fluid datasets of COVID-19 and asthma were obtained from the GEO and GSV database. A series of analyses of common host factors for COVID-19 and asthma were conducted, including PPI network construction, module analysis, enrichment analysis, inference of the upstream pathway activity of host factors, tissue-specific analysis and drug candidate prediction. Finally, the key host factors were verified in the GSE152418 and GSE164805 datasets.

Results

192 overlapping host factors were obtained by analyzing the intersection of asthma and COVID-19. FN1, UBA52, EEF1A1, ITGB1, XPO1, NPM1, EGR1, EIF4E, SRSF1, CCR5, PXN, IRF8 and DDX5 as host factors were tightly connected in the PPI network. Module analysis identified five modules with different biological functions and pathways. According to the degree values ranking in the PPI network, EEF1A1, EGR1, UBA52, DDX5 and IRF8 were considered as the key cohost factors for COVID-19 and asthma. The H₂O₂, VEGF, IL-1 and Wnt signaling pathways had the strongest activities in the upstream pathways. Tissue-specific enrichment analysis revealed the different expression levels of the five critical host factors. LY294002, wortmannin, PD98059 and heparin might have great potential to evolve into therapeutic drugs for COVID-19 and asthma comorbidity. Finally, the validation dataset confirmed that the expression of five key host factors were statistically significant among COVID-19 groups with different severity and healthy control subjects.

Conclusions

This study constructed a network of common host factors between asthma and COVID-19 and predicted several drugs with therapeutic potential. Therefore, this study is likely to provide a reference for the management and treatment for COVID-19/asthma comorbidity.

Palmatine Derivatives as Potential Antiplatelet Aggregation Agents via Protein Kinase G/Vasodilator-Stimulated Phosphoprotein and Phosphatidylinositol 3-Kinase/Akt Phosphorylation

Sixty palmatine (PMT) derivatives were synthesized and evaluated for antiplatelet aggregation taking berberine as the lead, and the structure-activity relationship was first systematically described. Among them, compound 2v showed the best potency in reducing adenosine diphosphate (ADP)-induced platelet aggregation in a dose-dependent manner. It greatly suppressed ADP-induced platelet aggregation, activation, and Akt phosphorylation in vitro and ex vivo after oral administration to mice. It also effectively inhibited carrageenan-induced thrombus formation in the mouse tail and lung, as well as reduced the serum P-selectin level. Compound 2v might simultaneously bind to protein kinase G to improve vasodilator-stimulated phosphoprotein phosphorylation and bind to phosphatidylinositol 3-kinase to inhibit Akt phosphorylation, which synergically reduced platelet aggregation, thereby achieving antithrombotic efficacy. Therefore, PMT derivatives constituted a novel family of antiplatelet aggregation agents with the advantage of a good safety profile, worthy of further investigation.

Fibroblast growth factor-21 as a novel metabolic factor for regulating thrombotic homeostasis

Fibroblast growth factor-21 (FGF-21) performs a wide range of biological functions in organisms. Here, we report for the first time that FGF-21 suppresses thrombus formation with no notable risk of bleeding. Prophylactic and therapeutic administration of FGF-21 significantly improved the degree of vascular stenosis and reduced the thrombus area, volume and burden. We determined the antithrombotic mechanism of FGF-21, demonstrating that FGF-21 exhibits an anticoagulant effect by inhibiting the expression and activity of factor VII (FVII). FGF-21 exerts an antiplatelet effect by inhibiting platelet activation. FGF-21 enhances fibrinolysis by promoting tissue plasminogen activator (tPA) expression and activation, while inhibiting plasminogen activator inhibitor 1 (PAI-1) expression and activation. We further found that FGF-21 mediated the expression and activation of tPA and PAI-1 by regulating the ERK1/2 and TGF-β/Smad2 pathways, respectively. In addition, we found that FGF-21 inhibits the expression of inflammatory factors in thrombosis by regulating the NF-κB pathway.

Regulation of Key Antiplatelet Pathways by Bioactive Compounds with Minimal Bleeding Risk

Cardiovascular disease is strongly influenced by platelet activation. Platelet activation and thrombus formation at atherosclerotic plaque rupture sites is a dynamic process regulated by different signaling networks. Therefore, there are now focused efforts to search for novel bioactive compounds which target receptors and pathways in the platelet activation process while preserving normal hemostatic function. The antiplatelet activity of numerous fruits and vegetables and their multiple mechanisms of action have recently been highlighted. In this review, we review the antiplatelet actions of bioactive compounds via key pathways (protein disulfide isomerase, mitogen-activated protein kinases, mitochondrial function, cyclic adenosine monophosphate, Akt, and shear stress-induced platelet aggregation) with no effects on bleeding time. Therefore, targeting these pathways might lead to the development of effective antiplatelet strategies that do not increase the risk of bleeding.

Berberine and Its Main Metabolite Berberrubine Inhibit Platelet Activation Through Suppressing the Class I PI3Kβ/Rasa3/Rap1 Pathway

Background: Berberine (BBR), a natural product, was reported to inhibit platelet aggregation; however, the molecular mechanisms remain unclear. This study aims to investigate the effects and mechanisms of BBR in inhibiting platelet activation and thrombus formation. Methods: Flow cytometry, immunofluorescence, and Western blot were used to determine the inhibitory effects and mechanisms of BBR and its main metabolite berberrubine (M2) on platelet activation in vitro and ex vivo. Purified integrin αIIbβ3, class I PI3K kit, and molecular docking were used to identify the possible targets of BBR and M2. A carrageenan-induced mouse thrombosis model was used to evaluate the effects of BBR on thrombus formation in vivo. Results: In vitro, BBR and M2 significantly inhibited ADP-induced integrin αIIbβ3 activation, reduced the level of P-selectin on the platelet membrane, and suppressed the binding of fibrinogen to the platelets. In this process, BBR and M2 greatly suppressed the PI3K/Akt pathway and inhibited Rasa3 membrane translocation and Rap1 activation. Furthermore, BBR and M2 selectively inhibited class I PI3Kβ, perhaps through binding to its active site. The activities of BBR were stronger than those of M2. After oral administration, BBR significantly inhibited the PI3K/Akt pathway and Rap1 activation and suppressed ADP-induced platelet activation and carrageenan-induced thrombosis in mice without prolonging bleeding time. Conclusions: We reveal for the first time the possible targets and mechanisms of BBR and M2 in inhibiting platelet activation. Our research may support the future clinical application of BBR as an antiplatelet drug in the prevention or treatment of thrombotic diseases.

FXII regulates the formation of deep vein thrombosis via the PI3K/AKT signaling pathway in mice

Deep vein thrombosis (DVT) is a common peripheral vascular disease, which may result in pulmonary embolism and is accompanied by endothelial injury. However, the pathogenesis of DVT remains unclear. Coagulation factor XII (FXII), as an important coagulation factor, has been reported to be closely associated with thrombosis. However, the association between FXII protein and DVT formation is not yet fully understood. The present study examined the effects of FXII protein on DVT formation and aimed to reveal the underlying mechanism. In the present study, histological characterization of the femoral vein tissue was examined by hematoxylin and eosin staining. The damage to the femoral vein tissue was examined by TUNEL assay. Superoxide dismutase (SOD) and malondialdehyde (MDA) concentrations were examined using ELISA. Tumor necrosis factor (TNF)‑α, interleukin (IL)‑6, IL‑8 and phosphoinositide 3‑kinase (PI3K)/AKT signaling were determined by ELISA, immunohistochemical staining and western blot analysis. The results demonstrated that thrombosis, FXII protein, cell apoptosis and the SOD concentrations were decreased, while the MDA concentrations were increased in mice with DVT compared with the control or sham groups. TNF‑α, IL‑6, IL‑8 and PI3K/AKT signaling was also upregulated in the mice with DVT. Furthermore, the knockdown of FXII significantly upregulated the SOD concentrations and downregulated thrombosis and cell apoptosis, as well as the MDA concentrations in mice with DVT. The knockdown of FXII also significantly downregulated the protein expression of TNF‑α, IL‑6 and IL‑8, and the activation of PI3K/AKT signaling. Additionally, LY294002 pre‑treatment markedly downregulated thrombosis and cell apoptosis and the MDA content, whereas it upregulated the SOD concentrations in mice with DVT. LY294002 pre‑treatment also significantly downregulated the TNF‑α, IL‑6 and IL‑8 protein levels. Taken together, the present study demonstrates that FXII protein promotes DVT via the activation of PI3K/AKT signaling by inducing an inflammatory response. Targeting FXII protein may thus prove to be a potential approach for the treatment of DVT.

Purification and Characterization of Novel Collagen Peptides against Platelet Aggregation and Thrombosis from Salmo salar

Collagen is a rich source of bioactive peptides and is widely distributed in the skin and bone tissue. In this study, collagen from Salmo salar skin was hydrolyzed with Alcalase or Protamex followed by simulated digestion, YMC ODS-A C18 separation, and ESI-MS/MS analysis. A total of 19 peptides were identified and synthesized for investigation of their antiplatelet activities. Hyp-Gly-Glu-Phe-Gly (OGEFG) and Asp-Glu-Gly-Pro (DEGP) exhibited the most potent activity against ADP-induced platelet aggregation among them with IC₅₀ values of 277.17 and 290.00 μM, respectively, and inhibited the release of β-TG and 5-HT in a dose-dependent manner significantly. Single oral administration of OGEFG and DEGP also inhibited thrombus formation in a ferric chloride-induced arterial thrombosis model at a dose of 200 μmol/kg body weight and did not prolong the bleeding time or cause an immune response in mice. Therefore, our findings indicated that collagen peptides had a potential to be developed into an effective specific medical food in the prevention of thrombotic diseases.

A novel di-peptide Met-Glu from collagen hydrolysates inhibits platelet aggregation and thrombus formation via regulation of Gq-mediated signaling

Increasing evidence has shown that collagen peptides had various biological activities. In this study, a novel antiplatelet peptide Met-Glu (ME) was separated and identified from silver carp skin by YMC ODS-A C18 separation and ESI-MS/MS analysis. Peptide ME inhibited platelet aggregation and secretion of platelet granules induced by ADP, thrombin and collagen, and significantly attenuated ferric chloride-induced thrombus formation in rats. It did not prolong the bleeding time in mice even at the dose of 300 μmol/kg body weight that showed potent anti-thrombosis effects. Additionally, peptide ME targeted at Gq-protein to downregulate the phosphorylation of PLCβ, an important upstream effector of PI3K/Akt and Erk/MAPK signaling to inhibit intracellular calcium ion mobilization. These results suggest that peptide ME inhibited thrombosis in vivo and inhibited Gq-mediated signaling in platelets, indicating the possibility that ME could potentially be developed as a novel therapeutic agent in the prevention and treatment of thrombotic diseases. PRACTICAL APPLICATIONS: Cardiovascular diseases (CVDs) are the leading cause of mortality and morbidity worldwide. The proximal cause of CVDs is intravascular thrombosis formation, which mostly results from platelet activation, aggregation, and granules secretion. Traditional drugs in the prevention of thrombotic disease, such as aspirin and clopidogrel, are still limited for their side effects, especially bleeding complications. Collagen is a natural source for bioactive peptides and our previous study has shown that collagen peptides could inhibit platelet aggregation in vitro. Understanding the mechanism of collagen peptides on regulation of platelet activation and their in vivo anti-thrombosis activities were important for the development of novel-specific medical food in the prevention of thrombotic diseases.

Pharmacological actions of miltirone in the modulation of platelet function

Salvia miltiorrhiza Bunge contains various active constituents, some of which have been developed as commercially available medicine. Moreover, some other ingredients in Salvia miltiorrhiza play roles in anti-platelet activity. The aim of the present study was to investigate the effects and the underlying mechanism of miltirone, a lipophilic compound of Salvia miltiorrhiza Bunge. The ability of miltirone to modulate platelet function was investigated by a variety of in vitro and in vivo experiments. Platelet aggregation and dense granule secretion induced by various agonists were measured with platelet aggregometer. Clot retraction and spreading were imaged by digital camera and fluorescence microscope. Ferric chloride-induced carotid injury model and pulmonary thromboembolism model were used to check miltirone antithrombotic effect in vivo. To elucidate the mechanisms of anti-platelet activity of miltirone, flow cytometry and western blotting were performed. Miltirone (2, 4, 8 µM) was shown to suppress platelet aggregation, dense granule, and α granule secretion in a dose-dependent manner. Meanwhile, miltirone inhibited the clot retraction and spreading of washed platelets. It reduced the phosphorylation of PLCγ2, PKC, Akt, GSK3β and ERK1/2 in the downstream signal pathway of collagen receptor. It also reduced the phosphorylation of Src and FAK in the integrin αIIbβ3-mediated "outside-in" signaling, while it did not suppress the phosphorylation of β3. In addition, miltirone prolonged the occlusion time and reduced collagen/epinephrine-induced pulmonary thrombi. Miltirone suppresses platelet "inside-out" and "outside-in" signaling by affecting PLCγ₂/PKC/ERK1/2, PI3K/Akt, and Src/FAK signaling. Therefore, miltirone might represent a potential anti-platelet candidate for the prevention of thrombotic disorders.

Effects of diosgenin and its derivatives on atherosclerosis

The effects of diosgenin are discussed with respect to endothelial dysfunction, lipid profile, macrophage foam cell formation, VSMC viability, thrombosis and inflammation during the formation of atherosclerosis.

Amides, Isoquinoline Alkaloids and Dipeptides from the Aerial Parts of Piper mullesua

One undescribed amide, pipermullesine A, two undescribed isoquinoline alkaloids, pipermullesines B and C, and six undescribed dipeptides, pipermullamides A-F, along with 28 known compounds, were isolated from the aerial parts of Piper mullesua. The structures of the undescribed compounds were elucidated based on the analysis of 1D and 2D NMR and MS data. Furthermore, the structures of pipermullesines A-C were confirmed by single crystal X-ray diffraction analysis. All isolates were evaluated for inhibitory activity against platelet aggregation induced by thrombin (IIa) or platelet-activating factor (PAF). (-)-Mangochinine, pellitorine, and (2E,4E)-N-isobutyl-2,4-dodecadienamide showed weak inhibitory activity against rabbit platelet aggregation induced by PAF, with IC50 values of 470.3 µg/mL, 614.9 µg/mL, and 579.7 µg/mL, respectively.

Ligustrazine inhibits platelet activation via suppression of the Akt pathway

Aberrant activation of platelets has a critical role in thrombotic vascular events, including atherosclerosis, arterial thrombosis and myocardial infarction. The process of platelet activation is associated with multiple intracellular signaling pathways, including the phosphoinositide 3‑kinase/AKT serine/threonine kinase (Akt) pathway. The well‑known medicinal herb Rhizoma Ligusticum Wallichii (RLW) has long been used in China to clinically treat various cardiovascular disorders. As the most pharmacologically active component of RLW, ligustrazine has been demonstrated to possess a potent antiplatelet activity. However, the precise mechanisms mediating the bioactivities of ligustrazine have not been thoroughly elucidated. The present study evaluated the effects of ligustrazine hydrochloride (LH; the clinical‑grade form of ligustrazine) on platelet activation and investigated the underlying molecular mechanisms. In vitro and ex vivo platelet activation models were used, established by stimulating rat platelet‑rich plasma either with the platelet activator adenosine diphosphate (ADP) or with the specific Akt pathway activator insulin‑like growth factor‑1 (IGF‑1). The results demonstrated that treatment with LH significantly and dose‑dependently inhibited ADP‑induced platelet aggregation, in addition to thromboxane A2 (TXA2) secretion and intracellular Ca2+ mobilization in platelets, in vitro and ex vivo. In addition, LH markedly suppressed ADP‑induced Akt phosphorylation in vitro and ex vivo. Furthermore, LH markedly inhibited IGF‑1‑induced Akt phosphorylation, platelet aggregation, TXA2 formation and Ca2+ mobilization in vitro. Finally, LH was able to reverse adrenaline‑induced shortening of bleeding time. Taken together, these results suggested that ligustrazine possesses a broad range of antiplatelet activities without apparent hemorrhagic side-effects, and suppression of Akt signaling may be one of the mechanisms by which ligustrazine exerts its antiplatelet activities.

Combination of Circulating miRNA-320a/b and D-Dimer Improves Diagnostic Accuracy in Deep Vein Thrombosis Patients

BACKGROUND D-dimer tests have been widely used to rule-out deep venous thrombosis (DVT), but with low specificity. Circulating microRNAs (miRNAs) are novel promising biomarkers in diverse diseases. The purpose of our study was to identify the diagnostic abilities of circulating miRNA-320a/b and to assess their correlation with plasma D-dimer in DVT and post-thrombotic syndrome (PTS) patients. MATERIAL AND METHODS Plasma samples were taken from 30 DVT patients, 30 PTS patients, and 30 age- and sex-matched healthy volunteers. Quantitative real-time PCR (qPCR) assay and turbidimetric immunoassay were conducted to assess the concentrations of miRNA-320a/b and D-dimer in plasma. RESULTS Circulating miRNA-320a and miRNA-320b were significantly upregulated in DVT patients with fold changes of 1.58 and 1.79, respectively. The receiver operating characteristic (ROC) curve analysis showed area under the curve (AUC) values of 0.70 (95% CI: 0.56-0.83) for miRNA-320a and 0.79 (95% CI: 0.67-0.90) for miRNA-320b. Moreover, plasma levels of miRNA-320b were associated with D-dimer values (r=0.52, 95% CI: 0.19-0.74) in DVT. However, no significant changes in plasma miRNA-320a/b and D-dimer were detected in PTS patients. CONCLUSIONS Compared with controls, circulating miRNA-320a/b was differentially expressed in DVT. Simultaneous detection of miRNA-320a/b with D-dimer may improve diagnostic accuracy of DVT.

Modified Abietane Diterpenoids from Whole Plants of Selaginella moellendorffii

A new modified abietane diterpenoid, (3S,4S,5R,10S)-18(4→3)-abeo-3,4,12,18-tetrahydroxy-8,11,13-abietatrien-7-one (1), and two novel dimers, selaginedorffones A (2) and B (3), featuring a new cyclohexene moiety that was biogenetically constructed from two modified abietane diterpenoids through a Diels-Alder reaction were obtained from a methanolic extract of Selaginella moellendorffii, a traditional Chinese herb. The structures of 1-3 were identified by a combination of NMR spectroscopic analysis and ECD calculations. In the present study, diterpenoids were identified from S. moellendorffii for the first time, which supports the presence of diterpene synthases in this plant. These three diterpenoids (1-3) were evaluated for their growth-inhibitory activities against several human cancer cell lines. Of these substances, selaginedorffone B (3) showed cytotoxicity against the MCF-7 human-breast-cancer-cell line (IC₅₀ 9.0 μM).

Circulating microRNA expression and their target genes in deep vein thrombosis: A systematic review and bioinformatics analysis

BACKGROUND

Clinically, D-dimer is the only established biomarker for the diagnosis of deep vein thrombosis (DVT). However, low specificity discounts its diagnostic value. Several publications have illustrated the differentially expressed circulating microRNAs (miRNAs) and their potential diagnostic values for DVT patients. Therefore, we systematically evaluated present researches and further performed bioinformatics analysis, to provide new insights into the diagnosis and underlying mechanisms of miRNAs in DVT.

METHODS

Databases PubMed, Web of Science, and Embase were searched from January 2000 to April 2017. Articles on circulating miRNAs expression in DVT were retrieved and reference lists were handpicked. Bioinformatics analysis was conducted for further evaluation.

RESULTS

Eventually, the eligibility criteria for inclusion in this study were met by 3 articles, which consisted of 13 specially expressed miRNAs and 149 putative target genes. Two representative KEGG pathways, vascular endothelial growth factor and phosphatidylinositol 3'-kinase (PI3K)-Akt signaling pathway, seemed to participate in the regulatory network of thrombosis.

CONCLUSIONS

Despite the potential diagnostic value and regulation effect, the results of circulating miRNAs used as biomarkers for DVT are not so encouraging. More in-depth and larger sample investigations are needed to explore the diagnostic and therapeutic values of miRNAs for DVT.