Dual-target synergistic antithrombotic mechanism of a dabigatran etexilate analogue (HY023016).

Thrombin has long been considered a desirable antithrombotic target, but anti-thrombin therapy without anti-platelet therapy has never achieved the ideal effect. HY023016, derived from dabigatran etexilate, exhibited a potent antithrombotic efficacy. In the present study, mechanisms underlying this effect were explored. HY023016 strongly decreased the binding of thrombin to recombinant GPIbα N-terminal sequence, which was confirmed by surface plasmon resonance. Flow cytometry revealed that HY023016 selectively decreased the binding of antibody to GPIbα and inhibited the washed human platelet aggregation induced by thrombin. Fluorescence experiment showed that HY023016 remarkably inhibited exosite II by a loss of affinity for the γ'-peptide of fibrinogen. Using intravital microscopy, we observed and recorded the dynamic process of thrombus formation and found that HY023016 effectively prevented thrombus formation in rat arteriovenous shunt thrombosis model. On the basis of these findings, we propose that HY023016 provides a novel insight into the antithrombotic mechanism, which exerts synergistic anticoagulant and antiplatelet effects through thrombin and GPIbα.

Effect of Autophagy Regulated by Sirt1/FoxO1 Pathway on the Release of Factors Promoting Thrombosis from Vascular Endothelial Cells.

Factors promoting thrombosis such as von Willebrand factor (vWF) and P-selectin are essential for the development of atherosclerosis (AS) and arterial thrombosis. The processing, maturation and release of vWF are regulated by autophagy of vascular endothelial cells. The Sirt1/FoxO1 pathway is an important pathway to regulate autophagy of endothelial cells, therefore the Sirt1/FoxO1 pathway may be an important target for the prevention of thrombosis. We investigated the role of ox-LDL in the release of vWF and P-selectin and the expression of Sirt1 and FoxO1 by Western Blot, Flow Cytometry, ELISA, and tandem fluorescent mRFP-GFP-LC3. We found that vWF and P-selectin secretion increased and Sirt1/FoxO1 pathway was depressed in human umbilical vein endothelial cells (HUVEC) when treated with ox-LDL. Moreover, the expression of autophagy-related protein LC3-II/I and p62 increased. Then, we explored the relationship between autophagy regulated by the Sirt1/FoxO1 pathway and the secretion of vWF and P-selectin. We found that Sirt1/FoxO1, activated by the Sirt1 activators resveratrol (RSV) and SRT1720, decreased the secretion of vWF and P-selectin, which can be abolished by the autophagy inhibitor 3-MA. The expression of Rab7 increased when Sirt1/FoxO1 pathway was activated, and the accumulation of p62 was decreased. Autophagy flux was inhibited by ox-LDL and Sirt1/FoxO1 pathway might enhance autophagy flux through the promotion of the Rab7 expression. Taken together, our data suggest that by enhancing autophagy flux and decreasing the release of vWF and P-selectin, the Sirt1/FoxO1 pathway may be a promising target to prevent AS and arterial thrombosis.

Design, synthesis and antithrombotic evaluation of novel non-peptide thrombin inhibitors.

Ten derivatives of 4-((1,2,3,4-tetrahydrobenzo[4,5]imidazo[1,2-a]pyrazin-1-yl)methyl)benzimida-mide (I-1∼I-2, II-1∼II-8) were designed, synthesized and evaluated for their inhibitory effect on human thrombin. Compound II-7 (IC50=82.8nM), which showed the strongest thrombin inhibitory activity among the tested compounds, was chosen as the lead compound, and ten carbamate derivatives (II-9a∼II-13a, II-9b∼II-12b, II-14) were prepared and evaluated for their anticoagulant activity. The results indicate that most of the tested compounds exhibit a certain degree of inhibitory effect on thrombin-induced platelet aggregation, among which compounds II-11a (IC50=8.16µM) and II-14 (IC50=1.95µM) show better anti-platelet aggregation activity than the others. The in vivo experimental results in rat venous thrombosis model also demonstrate compounds II-11a and II-14 can significantly reduce thrombosis in a dose-response manner. It is worth pointing out that the enhanced potency of compound II-14 may be the synergetic effect of 2-hydroxymethyl-3,5,6-trimethylpyrazine (HTMP) and II-7 which are generated by hydrolysis in vivo.

Discovery and SAR study of 2-(1-propylpiperidin-4-yl)-3H-imidazo[4,5-c]pyridine-7-carboxamide: A potent inhibitor of poly(ADP-ribose) polymerase-1 (PARP-1) for the treatment of cancer.

A series of imidazo[4,5-c]pyridine-7-carboxamide derivatives as poly(ADP-ribose) polymerase (PARP) inhibitors have been developed. All target compounds were evaluated for their PARP-1 inhibitory activity and some were further assessed for cellular potency. These efforts led to identification of a novel PARP-1 inhibitor 2-(1-propylpiperidin-4-yl)-3H-imidazo[4,5-c]pyridine-7-carboxamide 11a (XZ-120312). 11a displayed strong inhibition against the PARP-1 enzyme with an IC50 of 8.6±0.6 nM and excellent potentiation of temozolomide cytotoxicity in cancer cell lines SW-620, MDA-MB-468 and A549 by 4.0, 3.0 and 7.7 times, respectively.

Design, synthesis and antithrombotic evaluation of novel dabigatran etexilate analogs, a new series of non-peptides thrombin inhibitors.

Thrombin is a serine protease that plays a key role in blood clotting, which makes it a promising target for the treatment of thrombotic diseases. Dabigatran is direct potent thrombin inhibitor. Based on bioisosteric and scaffold hopping principle, two dabigatran mimics (I-1 and II-1) in which the benzamidine moiety of dabigatran was replaced by a tricyclic fused scaffold were designed, synthesized and evaluated for their in vitro activities for inhibiting thrombin. The results reveal that compounds I-1 (IC50=9.20nM) and II-1 (IC50=7.48nM) are potent direct thrombin inhibitors and the activity is in the range of reference drug. On this basis, twenty-two ester and carbamate derivatives of I-1 or II-1 were prepared and evaluated for their anticoagulant activity. Prodrugs I-4a (IC50=0.73µM), I-4b (IC50=0.75µM), II-2a (IC50=1.44µM) and II-2b (IC50=0.91µM) display excellent effects of inhibiting thrombin induced-platelet aggregation. Moreover, compounds I-9 and II-4, which contain a cleavable moiety with anti-platelet activity, show the best anticoagulant efficacy among the tested compounds in the rat venous thrombosis model. The compounds which have better in vitro and in vivo activity were subjected to rat tail bleeding test, and the result demonstrates that compound I-9 is less likely to have bleeding risk than dabigatran etexilate.

Design, Synthesis, and Biological Evaluation of Dabigatran Etexilate Mimics, a Novel Class of Thrombin Inhibitors.

Human α-thrombin is a particularly promising target for anticoagulant therapy, and identification of oral small-molecular inhibitors of thrombin remains a research focus. On the basis of the X-ray crystal structure of human α-thrombin and its inhibitor dabigatran, we designed and synthesized a series of dabigatran etexilate mimics containing a novel tricyclic fused scaffold. The biological evaluations reveal that all of the compounds possess moderate activity of antiplatelet aggregation induced by thrombin in vitro. Moreover, compound I-8, which contains 2-hydroxymethyl-3,5,6-trimethylpyrazine (HTMP), a cleavable moiety with antiplatelet activity, shows the best anticoagulant effect among the tested compounds in vivo. Those synthesized compounds that have better in vitro activity were subjected to bleeding complication tests, and the results demonstrate that the novel compounds are less likely to have bleeding risk than dabigatran etexilate.

Synthesis and pharmacological evaluation of novel limonin derivatives as anti-inflammatory and analgesic agents with high water solubility.

A novel series of water-soluble derivatives of limonin were synthesized by introducing various tertiary amines onto the C (7)-position of limonin. Ten target compounds were characterized and screened for their anti-inflammatory and analgesic activity in vivo. Compound 3c exhibited the strongest analgesic and anti-inflammatory activity among the limonin and its derivatives tested; its analgesic activity is more potent than that of aspirin and its anti-inflammatory activity is stronger than that of naproxen.

NLRP3 inflammasome sequential changes in Staphylococcus aureus-induced mouse model of acute rhinosinusitis.

The NLR pyrin domain containing 3 (NLRP3) inflammasome plays a crucial role in lung disease and may have a similar role in upper respiratory tract inflammation. We therefore constructed a C57BL/6 mouse model of acute rhinosinusitis induced by Staphylococcus aureus and investigated the role of the NLRP3 inflammasome in this model. Mice were classified as non-inoculated group (group A) and inoculated groups (groups B, C, D and E, sacrificed 1, 3, 7 and 14 days after inoculation, respectively). Hematoxylin-eosin staining showed that each group had inflammatory cell infiltration, except group A. The damage of the nasal mucosa was aggravated gradually over time. Western blot and immunofluorescence showed that the structural proteins of the NLRP3 inflammasome (NLRP3, ASC (apoptosis-associated speck-like protein containing CARD), procaspase-1) in groups B, C, D and E were increased gradually. But they were reduced in group B compared with group A, except for NLRP3. Western blot showed that the cleavage fragment of procaspase-1, p20 in groups B, C, D and E was increased gradually. Real-time PCR showed that the corresponding mRNAs of the structural proteins were changed the same as their proteins. IL-1ß mRNA and mature IL-1ß protein were increased gradually in groups A, B, C, D and E. These results indicate that NLRP3 inflammasome activation was associated with the acute rhinosinusitis, and that there was a positive correlation between the expression level of the NLRP3 inflammasome and the severity of acute rhinosinusitis.

Effects of IL-17 on expression of GRO-α and IL-8 in fibroblasts from nasal polyps.

Recent studies indicated that interleukin (IL)-17, growth-related oncogene (GRO)-α and IL-8 play an important role in the pathogenesis of nasal polyps. However, the effects of the increased amount of IL-17 and the production of GRO-α and IL-8 in human nasal polyp fibroblasts are not completely understood. This study aimed to determine the effects of the increased IL-17 on the changes of GRO-α and IL-8 expression in human nasal polyp fibroblasts and further investigate the mechanism of neutrophil infiltration in nasal polyps. Nasal polyp fibroblasts were isolated from six cases of human nasal polyps, and the cells were stimulated with five different concentrations of IL-17. Real-time fluorescence quantitative polymerase chain reaction (RT-PCR) was used to detect the mRNA expression of GRO-α and IL-8. The mRNA of GRO-α and IL-8 was expressed in unstimulated controls and remarkably increased by stimulation with IL-17. Moreover, the levels of GRO-α and IL-8 produced by fibroblasts were increased gradually with the increases in IL-17 concentrations. The present study showed that nasal fibroblasts can produce GRO-α and IL-8, and their production is remarkably enhanced by IL-17 stimulation, thereby clarifying the mechanism of the IL-17 mediated neutrophil infiltration in nasal polyps. These findings might provide a rationale for using IL-17 inhibitors as a treatment for nasal inflammatory diseases such as nasal polyps.

Design, synthesis and antithrombotic evaluation of novel dabigatran prodrugs containing methyl ferulate.

A novel series of prodrugs containing dabigatran and methyl (E)-3-(4-hydroxy-2-methoxyphenyl)propenoate (methyl ferulate) were synthesized. All of them reveal the effect of thrombin-induced anti-platelet aggregation in vitro. In addition, in vivo experiment shows that one of the target compounds, X-2 (ED50=3.7 ± 1.0 µmol/kg) possesses a more potent activity for inhibiting venous thrombosis than that of dabigatran etexilate (ED50=7.8 ± 1.5 µmol/kg).

Inhibition of IL-4/STAT6/IRF4 signaling reduces the epithelial-mesenchymal transition in eosinophilic chronic rhinosinusitis with nasal polyps.

BACKGROUND: Previous studies have shown that epithelial-to-mesenchymal transition (EMT) in nasal epithelial cells is critical for tissue remodeling of chronic rhinosinusitis with nasal polyps (CRSwNP). However, the precise mechanism underlying the EMT remains poorly understood. This study aimed to investigate the role of interleukin-4 (IL-4)/signal transducer and activator of transcription 6 (STAT6)/interferon regulatory factor 4 (IRF4) signaling pathway on EMT in eosinophilic CRSwNP. METHODS: We performed quantitative real-time polymerase chain reaction, immunohistochemistry, immunofluorescent staining, and Western blotting to evaluate the expression of STAT6, IRF4, and EMT markers in sinonasal mucosal samples. Effects of IL-4-induced EMT were determined using primary human nasal epithelial cells (hNECs) from patients with eosinophilic CRSwNP. Wound scratch assay, cell morphology, Western blotting, and immunofluorescence cytochemistry were performed to evaluate EMT, and EMT-related markers. Next, human THP-1 monocytic cells were stimulated by phorbolate-12-myristate-13-acetate to differentiate into M0 and were subsequently polarized into M1 with lipopolysaccharide and interferon-γ, M2 with IL-4. The markers of the macrophage phenotype were assessed by Western blotting. The co-culture system was built to explore the interaction between macrophages (THP-1 cells) and hNECs. After co-culture with M2 macrophages, EMT-related markers of primary hNECs were evaluated by immunofluorescence cytochemistry and Western blotting. Enzymelinked immunosorbent assays were used to detect transforming growth factor beta 1 (TGF-ß1) in THP-1-derived supernatants. RESULTS: STAT6 and IRF4 mRNA and protein expression were significantly upregulated in both eosinophilic and noneosinophilic nasal polyps compared with control tissues. The expression of STAT6 and IRF4 in eosinophilic nasal polyps was higher than those in noneosinophilic nasal polyps. STAT6 and IRF4 were not only expressed in epithelial cells but also in macrophages. The number of STAT6+CD68+ cells and IRF4+CD68+ cells in eosinophilic nasal polyps was higher than those in noneosinophilic nasal polyps and control tissues. EMT was enhanced in eosinophilic CRSwNP compared to the healthy controls and noneosinophilic CRSwNP. IL-4-stimulated human nasal epithelial cells exhibited EMT characteristics. The hNECs co-cultured with M2 macrophages demonstrated high levels of EMT-related markers. The TGF-ß1 level was significantly induced by IL-4 and elevated (M2) rather than control macrophages. The inhibition of STAT6 by AS1517499 reduced the expression of IRF4 in epithelial cells and macrophages and counteracted IL-4-induced EMT in epithelial cells. CONCLUSION: In eosinophilic nasal polyps, IL-4 induces STAT6 signaling to upregulate IRF4 expression in epithelial cells and macrophages. IL-4 promotes EMT of hNECs through the STAT6/IRF4 signaling pathway. IL-4-induced M2 macrophages enhanced EMT of hNECs. Inhibition of STAT6 can downregulate the expression of IRF4 and suppress the EMT process, thus providing a new strategy for the treatment of nasal polyps.

Anti-inflammatory Effect of a Limonin Derivative In Vivo and Its Mechanisms in RAW264.7 Cells.

A potential new limonoid derivative, (12S,12aS)-6,6,8a,12a-tetramethyl-12-(5-(4-(piperidin-1-yl)butanoyl)furan-3-yl)decahydro-1H,3H-oxireno[2,3-d]pyrano[4',3':3,3a]isobenzofuro[5,4-f]isochromene-3,8,10(6H,9aH)-trione (I-C-1), has been screened for its anti-inflammatory activity. This study aimed to demonstrate the anti-inflammatory activities of I-C-1 and to further explore the underlying mechanisms of these activities in RAW264.7 macrophages. We verified the anti-inflammatory activity of I-C-1 in vivo by a carrageenan-induced paw edema model in rats and cotton pellet-induced granuloma in mice. Further, we found that I-C-1 significantly inhibited levels of pro-inflammatory cytokines such as interleukin (IL)-1ß, IL-6, and tumor necrosis factor (TNF)-α in lipopolysaccharide (LPS)-induced RAW264.7 cells. I-C-1 demonstrated strong inhibition of the NF-κB activation through repression of the IKKα and IKKß phosphorylations, as well as a significant suppression of the phosphatidylinositol 3-kinase (PI3K)/serine-threonine kinase (Akt) pathway, an upstream of the NF-κB pathway. Additionally, we verified the inhibitory effect of I-C-1 on PI3K phosphorylation by immunofluorescence assay and compared the effects of I-C-1 with the PI3K inhibitor LY294002 in IL-1ß, IL-6, and TNF-α levels. The data indicated that I-C-1 likely acts as an inhibitor of PI3K, exerting anti-inflammatory effects by inhibiting the PI3K/AKT/NF-κB signaling pathway. Based on these findings, we believe that I-C-1 has the potential to be further developed as a potential therapeutic agent for inflammatory-related diseases.

Effects of Blocking NLRP3 Inflammasome on Type II Innate Lymphoid Cell Response in Allergic Rhinitis.

Background: Type 2 innate lymphoid cells (ILC2s) and NLRP3 inflammasome are related to allergic and inflammatory responses. NLRP3 inflammasome inhibitor MCC950 was demonstrated to ameliorate allergic rhinitis (AR) in animal models. Objective: To elucidate the effect of MCC950 on ILC2 responses in AR. Methods: NLRP3 inflammasome, ILC2s, IL-5+ILC2s, IL-13+ILC2s, and Th2-related factors were examined in 30 AR patients. ILC2s were identified as Lin-CRTH2+CD127+lymphocytes. ILC2s isolated from PBMCs were stimulated with LPS plus ATP. The effect of MCC950, IL-1ß, and IL-18 on ILC2 responses was detected by flow cytometry. AR models were established in 60 BALB/c mice. Nasal symptoms and ILC2 responses in the AR models after MCC950 treatment were detected. Human nasal epithelial cells were stimulated with IL-13 (10 ng/mL) and treated with MCC950 (10 µM). Results: AR patients showed activated NLRP3 inflammasome and increased ILC2 responses compared to controls. NLRP3 inflammasome levels in the AR patients were positively related to the proportion of ILC2s, IL-5+ILC2s, and IL-13+ILC2s in total PBMCs. MCC950 treatment or IL-1ß/IL-18 suppression inhibited ILC2 proliferation and Th2-related factors (GATA3, RORα, IL-5, and IL-13). MCC950 administration alleviated frequencies of nasal rubbing and sneezes in the AR models. ILC2s, IL-5+ILC2s, and IL-13+ILC2s in mice were reduced by MCC950. MCC950 inhibited NLRP3 inflammasome in the in vitro models of AR. Conclusion: MCC950 inhibited ILC2 responses in AR and mice models, suggesting that blocking NLRP3 inflammasome may be a promising target for AR clinical treatment.

Design and performance study of grease spool-less relief valve.

The high resistance characteristic of the grease delivery process makes the centralized lubrication system easy to cause pipeline blockage during the grease supply process. The main objective of the present article is to design a non-spool relief valve device based on the round pipe. The plug shape characteristics of the grease flow in the tube are established by combining the hydrodynamic equation and the grease rheological model. The mathematical model, whose relationship between velocity and flow is derived, is established with the core pipe of the grease spool-less relief valve of flow resistance, so the factors affecting grease pipe flow are obtained. The numerical simulation method is used to simulate the lipid overflow process of the simplified model with different influence parameters. Tecplot 360 EX 2015 R1 is used as a post-processing software to derive velocity and pressure clouds for grease flow in a circular tube, to investigate the factors influencing the relief pressure and relief capacity of the relief valve, to derive general rules for grease relief pressure, grease relief capacity and grease flow pattern distribution, and to establish an evaluation model for the relief pressure and relief capacity of the relief valve. The performance research test platform of the grease spool-less relief valve is built, and NLGI1 lithium grease is selected to carry out the experimental study on the performance of the grease relief valve under different influence parameters. The safety, stability, and feasibility of the overflow valve working with the pumping system are verified.

Discovery of the First Selective IDO2 Inhibitor As Novel Immunotherapeutic Avenues for Rheumatoid Arthritis.

Indoleamine 2,3-dioxygenase 2 (IDO2), a closely related homologue of well-studied immunomodulatory enzyme IDO1, has been identified as a pathogenic mediator of inflammatory autoimmunity in preclinical models. Therapeutic targeting IDO2 in autoimmune diseases has been challenging due to the lack of small-molecule IDO2 inhibitors. Here, based on our previously developed IDO1/IDO2 dual inhibitor, guided by the homology model of the IDO2 structure, we discovered compound 22, the most potent inhibitor targeting IDO2 with good in vitro inhibitory activity (IDO2 IC50 = 112 nM). Notably, treatment with 22 alleviated disease severity and reduced inflammatory cytokines in both the collagen-induced arthritis (CIA) mice model and adjuvant arthritis (AA) rat model. Our study offered for the first time a selective small-molecule IDO2 inhibitor 22 with IC50 at the nanomolar level, which may be used not only as a candidate compound for the treatment of autoimmune diseases but also as a tool compound for further IDO2-related mechanistic study.

Dropouts From Sublingual Immunotherapy and the Transition to Subcutaneous Immunotherapy in House Dust Mite-Sensitized Allergic Rhinitis Patients.

Purpose: Both subcutaneous immunotherapy (SCIT) and sublingual immunotherapy (SLIT) are effective in reducing symptoms and medication scores and inducing long-term efficacy in patients with allergic rhinitis (AR). However, SLIT has been associated with poor patient adherence. This study investigates the factors impacting dropout rates from SLIT in house dust mite (HDM)-sensitized AR patients. Methods: A retrospective study was performed to analyze dropout rates and reasons in AR patients receiving Dermatophagoides farinae (Der f) SLIT with a follow-up period of 2 years. Results: A total of 719 HDM-sensitized AR patients received Der f-SLIT. Dropout rates increased with time and most occurred after 1 year of SLIT. By month 24, 654 (91%) patients had discontinued SLIT. The dropout rates by month 24 were 100, 90.1, and 91.1% in children <5 years old, children aged 5-18 years old, and adults ≥ 18 years old, respectively. Combination with allergic asthma and mono- or multi-sensitization to other aeroallergens did not affect the dropout rates. The most common self-reported reasons for dropouts were refusal of continuation, dissatisfaction with the efficacy, transition to SCIT, and adverse effects. Refusal of continuation increased with age, whereas transition to SCIT decreased with age. Ninety-seven cases transitioned from SLIT to SCIT, and the transition rates increased with time. Comorbid allergic asthma did not affect the transition rates. However, multi-sensitization was associated with a slightly higher rate of transition to SCIT. The most common reason for the transition was dissatisfaction with the efficacy (54.6%), which was only reported by patients older than 5 years. For children who began SLIT at younger than 5 years old, the most common reason (81.2%) for transition was age reaching 5 years. Conclusions: HDM-SLIT has a very high dropout rate, which is mainly due to refusal of continuation and dissatisfaction with the efficacy. Transitioning from SLIT to SCIT may help keep these patients on AIT and thus increase adherence and long-term efficacy.

Synthesis of novel ligustrazine derivatives as NA+/H+ exchange inhibitors.

A novel series of 3,5,6-trimethylpyrazine-2-methoxy (or methylamino) substituted benzoyl-guanidine derivatives were designed and synthesized as Na(+)/H(+) exchange (NHE) inhibitors. In this study, compounds with electron-withdrawing substituents on the benzene ring seemed to improve NHE-1 inhibitory activities. Compounds 6d, 6k, and 6l were found to be potent inhibitors of NHE-1 (IC(50)=3.0±1.6, 3.0±1.4, and 1.6±0.4 nmol/l, resp.). Furthermore, they showed a remarkable reduction of infarct size in the rat myocardial infarction model in vivo.

Synthesis and Na(+)/H(+) exchanger-1 inhibitory activity of substituted (quinolinecarbonyl)guanidine derivatives.

The Na(+)/H(+) exchanger (NHE) is a protein expressed in many mammalian cell types. It is involved in intracellular pH (pH(i)) homeostasis by exchanging extracellular Na(+) for intracellular H(+). To date, nine NHE isoforms (NHE1-NHE9) have been identified. NHE1 is the most predominant isoform expressed in mammalian cardiac muscle. A novel series of substituted (quinolinecarbonyl)guanidine derivatives were designed and synthesized as NHE inhibitors. Most compounds can inhibit NHE1-mediated platelet swelling in a concentration-dependent manner, among which compound 7f was the most active and more potent than cariporide. Furthermore, compound 7f has also been demonstrated to exhibit the in vivo cardioprotective effects against SD rat myocardial ischemic-reperfusion injury superior to those of cariporide.

Optimization of P2Y12 Antagonist Ethyl 6-(4-((Benzylsulfonyl)carbamoyl)piperidin-1-yl)-5-cyano-2-methylnicotinate (AZD1283) Led to the Discovery of an Oral Antiplatelet Agent with Improved Druglike Properties.

P2Y12 antagonists are widely used as antiplatelet agents for the prevention and treatment of arterial thrombosis. Based on the scaffold of a known P2Y12 antagonist AZD1283, a series of novel bicyclic pyridine derivatives were designed and synthesized. The cyclization of the ester substituent on the pyridine ring to the ortho-methyl group led to lactone analogues of AZD1283 that showed significantly enhanced metabolic stability in subsequent structure-pharmacokinetic relationship studies. The metabolic stability was further enhanced by adding a 4-methyl substituent to the piperidinyl moiety. Compound 58l displayed potent inhibition of platelet aggregation in vitro as well as antithrombotic efficacy in a rat ferric chloride model. Moreover, 58l showed a safety profile that was superior to what was observed for clopidogrel in a rat tail-bleeding model. These results support the further evaluation of compound 58l as a promising drug candidate.

A novel limonin derivate modulates inflammatory response by suppressing the TLR4/NF-κB signalling pathway.

In our previous studies, we have demonstrated that a novel water-soluble derivative of limonin, (12S,12aS,Z)-8-((2-(diethylamino)ethoxy)imino)-12-(furan-3-yl)-6,6,8a,12a-tetramethyldodecahydro-1H,3H-oxireno[2,3-d]pyrano[4',3':3,3a]isobenzofuro[5,4-f]isochromene-3,10(9aH)-dione (V-A-4), exhibited strong anti-inflammatory activity both in vitro and in vivo. The purpose of this study was to further explore the underlying mechanisms of such activity demonstrated by V-A-4. The protective effect of V-A-4 on the alleviation of xylene-induced ear swelling and carrageenan-induced subcutaneous air pouch model was detected in vivo. Furthermore, the in vitro effects of V-A-4 and its mechanisms of action were determined by colorimetric COX (ovine) inhibitor-screening assay and in lipopolysaccharide (LPS)-stimulated RAW264.7 cells. This study showed that V-A-4 does not exert anti-inflammatory effect through the inhibition of COX-1 or COX-2. Rather, it is exerted through the suppression of the secretion of nitric oxide (NO) and tumor necrosis factor-α (TNF-α), as well as through the infiltration of inflammatory cells. V-A-4 demonstrated strong inhibition of NF-κB activation through repression of IKKα and IKKß phosphorylations, which in turn leads to the phosphorylation and degradation of IκBα in LPS-induced RAW264.7 cells. Moreover, toll-like receptor 4 (TLR4) pathway was involved in the anti-inflammatory effect of V-A-4, which also played an important role in the down-regulation of LPS-mediated miR-146a and miR-155 expressions. These results encourage further development of V-A-4 as a potential candidate for the treatment of inflammatory diseases.