Discovery of P2Y2 Receptor Antagonist Scaffolds through Virtual High-Throughput Screening.

The human ATP- and UTP-activated P2Y2 receptor (P2Y2R) is a Gq protein-coupled receptor involved in several pathophysiological conditions including acute and chronic inflammation, cancer, and pain. Despite its potential as a novel drug target, only few P2Y2R antagonists have been developed so far, all of which suffer from severe drawbacks. These include (i) high polarity due to one or several negative charges resulting in low oral bioavailability, (ii) metabolic instability and generally poor pharmacokinetic properties, and/or (iii) lack of selectivity, which limits their utility for in vitro and in vivo studies aimed at target validation. In search of new druglike scaffolds for P2Y2R antagonists, we employed a structure-based virtual high-throughput screening approach utilizing the complex of a P2Y2R homology model with one of the most potent and selective orthosteric antagonists described so far, AR-C118925 (10). After virtual screening of 3.2 million molecules, 58 compounds were purchased and pharmacologically evaluated. Several novel antagonist scaffolds were discovered, and their binding modes at the human P2Y2R were analyzed by molecular docking studies. The investigated antagonists likely share a similar binding mode with 10 which includes accommodation of bulky, lipophilic groups in the putative orthosteric binding site of the P2Y2R. The discovered scaffolds and the elucidated structure-activity relationships provide a basis for the development of future drug candidates for the P2Y2R which have great potential as novel drugs.

P2Y12 antagonists: Approved drugs, potential naturally isolated and synthesised compounds, and related in-silico studies.

P2Y12 is a platelet surface protein which is responsible for the amplification of P2Y1 response. It plays a crucial role in platelet aggregation and thrombus formation through an ADP-induced platelet activation mechanism. Despite that P2Y12 platelets' receptor is an excellent target for developing antiplatelet agents, only five approved medications are currently in clinical use which are classified into thienopyridines and nucleoside-nucleotide derivatives. In the past years, many attempts for developing new candidates as P2Y12 inhibitors have been made. This review highlights the importance and the role of P2Y12 receptor as part of the coagulation cascade, its reported congenital defects, and the type of assays which are used to verify and measure its activity. Furthermore, an overview is given of the clinically approved medications, the potential naturally isolated inhibitors, and the synthesised candidates which were tested either in-vitro, in-vivo and/or clinically. Finally, we outline the in-silico attempts which were carried out using virtual screening, molecular docking and dynamics simulations in efforts of designing novel P2Y12 antagonists. Various phytochemical classes might be considered as a corner stone for the discovery of novel P2Y12 inhibitors, whereas a wide range of ring systems can be deliberated as leading scaffolds in that area synthetically and theoretically.

Lipids and Antiplatelet Therapy: Important Considerations and Future Perspectives.

Lipids play an essential role in platelet functions. It is known that polyunsaturated fatty acids play a role in increasing platelet reactivity and that the prothrombotic phenotype plays a crucial role in the occurrence of major adverse cardiovascular events. The ongoing increase in cardiovascular diseases' incidence emphasizes the importance of research linking lipids and platelet function. In particular, the rebound phenomenon that accompanies discontinuation of clopidogrel in patients receiving dual antiplatelet therapy has been associated with changes in the lipid profile. Our many years of research underline the importance of reduced HDL values for the risk of such a rebound effect and the occurrence of thromboembolic events. Lipids are otherwise a heterogeneous group of molecules, and their signaling molecules are not deposited but formed "on-demand" in the cell. On the other hand, exosomes transmit lipid signals between cells, and the profile of such changes can be monitored by lipidomics. Changes in the lipid profile are organ-specific and may indicate new drug action targets.

Structure activity relationship of 3-nitro-2-(trifluoromethyl)-2H-chromene derivatives as P2Y6 receptor antagonists.

Various 6-alkynyl analogues of a known 3-nitro-2-(trifluoromethyl)-2H-chromene antagonist 3 of the Gq-coupled P2Y6 receptor (P2Y6R) were synthesized using a Sonogashira reaction to replace a 6-iodo group. The analogues were tested in a functional assay consisting of inhibition of calcium mobilization in P2Y6R-expressing astrocytoma cells elicited by native P2Y6R agonist UDP. 6-Ethynyl and 6-cyano groups were installed, and the alkynes were extended through both alkyl and aryl spacers. The most potent antagonists, with IC50 of ~1 µM, were found to be trialkylsilyl-ethynyl 7 and 8 (3-5 fold greater affinity than reference 3), t-butyl prop-2-yn-1-ylcarbamate 14 and p-carboxyphenyl-ethynyl 16 derivatives, and 3 and 8 displayed surmountable antagonism of UDP-induced production of inositol phosphates. Other chain-extended terminal carboxylate derivatives were less potent than the corresponding methyl ester derivatives. Thus, the 6 position in this chromene series is suitable for derivatization with flexibility of substitution, even with sterically extended chains, without losing P2Y6R affinity. However, a 3-carboxylic acid or 3-ester substitution did not serve as a nitro bioisostere, as the affinity was eliminated. These compounds provide additional ligand tools for the underexplored P2Y6R, which is a target for inflammatory, neurodegenerative and metabolic diseases.

On-Ticagrelor Platelet Reactivity and Clinical Outcome in Patients Undergoing Percutaneous Coronary Intervention for Acute Coronary Syndrome.

BACKGROUND: A strong association between on-thienopyridine platelet reactivity (PR) and the risk of both thrombotic and bleeding events in acute coronary syndrome (ACS) patients undergoing percutaneous coronary intervention (PCI) has been demonstrated. However, no study has analyzed the relationship between on-ticagrelor PR and clinical outcome in this clinical setting. OBJECTIVES: We aimed to investigate the relationship between on-ticagrelor PR, assessed by the vasodilator-stimulated phosphoprotein (VASP) index, and clinical outcome in patients with ACS undergoing PCI. METHODS: We performed a prospective, multicenter, observational study of patients undergoing PCI for ACS. PR was measured using the VASP index following ticagrelor loading dose. The primary study endpoint was the rate of Bleeding Academic Research Consortium (BARC) type ≥2 at 1 year. The key secondary endpoint was the rate of major adverse cardiovascular events (MACE) defined as the composite of cardiovascular death, myocardial infarction, stroke, and urgent revascularization. RESULTS: We included 570 ACS patients, among whom 33.9% had ST-elevation myocardial infarction. BARC type ≥2 bleeding occurred in 10.9% and MACE in 13.8%. PR was not associated with BARC ≥2 or with MACE (p = 0.12 and p = 0.56, respectively). No relationship between PR and outcomes was observed, neither when PR was analyzed quantitatively nor when it was analyzed qualitatively (low on-treatment PR [LTPR] vs. no LTPR). CONCLUSION: On-ticagrelor PR measured by the VASP was not associated with bleeding or thrombotic events in ACS patients undergoing PCI. PR measured by the VASP should not be used as a surrogate endpoint in studies on ticagrelor.

Pharmacokinetics, mass balance, and metabolism of [14C]vicagrel, a novel irreversible P2Y12 inhibitor in humans.

Vicagrel, a novel irreversible P2Y12 receptor inhibitor, is undergoing phase III trials for the treatment of acute coronary syndromes in China. In this study, we evaluated the pharmacokinetics, mass balance, and metabolism of vicagrel in six healthy male Chinese subjects after a single oral dose of 20 mg [14C]vicagrel (120 µCi). Vicagrel absorption was fast (Tmax = 0.625 h), and the mean t1/2 of vicagrel-related components was ~38.0 h in both plasma and blood. The blood-to-plasma radioactivity AUCinf ratio was 0.55, suggesting preferential distribution of drug-related material in plasma. At 168 h after oral administration, the mean cumulative excreted radioactivity was 96.71% of the dose, including 68.03% in urine and 28.67% in feces. A total of 22 metabolites were identified, and the parent vicagrel was not detected in plasma, urine, or feces. The most important metabolic spot of vicagrel was on the thiophene ring. In plasma pretreated with the derivatization reagent, M9-2, which is a methylated metabolite after thiophene ring opening, was the predominant drug-related component, accounting for 39.43% of the radioactivity in pooled AUC0-8 h plasma. M4, a mono-oxidation metabolite upon ring-opening, was the most abundant metabolite in urine, accounting for 16.25% of the dose, followed by M3-1, accounting for 12.59% of the dose. By comparison, M21 was the major metabolite in feces, accounting for 6.81% of the dose. Overall, renal elimination plays a crucial role in vicagrel disposition, and the thiophene ring is the predominant metabolic site.

Switching a Xanthine Oxidase Inhibitor to a Dual-Target Antagonist of P2Y1 and P2Y12 as an Oral Antiplatelet Agent with a Wider Therapeutic Window in Rats than Ticagrelor.

ADP-mediated platelet aggregation is signaled through G protein-coupled receptors P2Y1 and P2Y12 on the platelet. The clinical effectiveness of inhibiting P2Y12 has been well established, and preclinical studies indicated that the inhibition of P2Y1 could provide equivalent antithrombotic efficacy as P2Y12 antagonists and reduce bleeding risks. On the basis of the 2-phenyl-1H-imidazole scaffold of our previously reported xanthine oxidase inhibitor WSJ-557, we first achieved the transition from the xanthine oxidase inhibitors to dual-target antagonists against P2Y1 and P2Y12. We described the structure-activity relationships of the 2-phenyl-1H-imidazole compounds, which led to the identification of the most potent antiplatelet agents, 24w and 25w, both showing a rapid onset of action in pharmacokinetic study. Furthermore, the rat model suggested that 24w demonstrated a wider therapeutic window than ticagrelor, displaying equivalent and dose-dependent antithrombotic efficacy with lower blood loss compared to ticagrelor at same oral dose. These results supported that 24w and 25w could be promising drug candidates.

An evaluation of ticagrelor for the treatment of sickle cell anemia.

INTRODUCTION: Ticagrelor is an antiplatelet agent approved for the treatment of patients with an acute coronary syndrome or a history of myocardial infarction. Considering the evidence demonstrating that ticagrelor-mediated inhibition of platelet activation and aggregation have beneficial effects in the treatment of thrombotic conditions, clinical studies have been conducted to evaluate the use of this drug for the treatment of sickle cell disease (SCD), demonstrating satisfactory tolerability and safety. AREAS COVERED: Clinical investigation has characterized the pharmacokinetic and pharmacodynamical profile, as well as the efficacy and safety of ticagrelor to prevent painful vaso-occlusive crisis (painful episodes and acute chest syndrome) in SCD patients. EXPERT OPINION: While phase 1 and 2 clinical trials demonstrated satisfactory tolerability and safety, the conclusion of phase 3 clinical trials is crucial to prove the efficacy of ticagrelor as a therapeutic option for the treatment of SCD. Thus, it is expected that ticagrelor, especially in combination with other drugs, will improve the clinical profile and quality of life of patients with SCD.

Profiling of a suramin-derived compound library at recombinant human P2Y receptors identifies NF272 as a competitive but non-selective P2Y2 receptor antagonist.

Extracellular nucleotides mediate multiple physiological effects such as proliferation, differentiation, or induction of apoptosis through G protein-coupled P2Y receptors or P2X ion channels. Evaluation of the complete physiological role of nucleotides has long been hampered by a lack of potent and selective ligands for all P2 subtypes. Meanwhile, for most of the P2 receptors, selective ligands are available, but only a few potent and selective P2Y2 receptor antagonists are described. This limits the understanding of the role of P2Y2 receptors. The purpose of this study was to search for P2Y2 receptor antagonists by a combinatorial screening of a library of around 415 suramin-derived compounds. Calcium fluorescence measurements at P2Y2 receptors recombinantly expressed in human 1321N1 astrocytoma cells identified NF272 [8-(4-methyl-3-(3-phenoxycarbonylimino-benzamido)benzamido)-naphthalene-1,3,5-trisulfonic acid trisodium salt] as a competitive P2Y2 receptor antagonist with a Ki of 19 µM which is 14-fold more potent than suramin at this receptor subtype. The SCHILD analysis of competitive inhibition resulted in a pA2 value of 5.03 ± 0.22 (mean ± SEM) with a slope not significantly different from unity. Among uracil-nucleotide-preferring P2Y receptors, NF272 shows a moderate selectivity over P2Y4 (3.6-fold) and P2Y6 (5.7-fold). However, NF272 is equipotent at P2Y1, and even more potent at P2Y11 and P2Y12 receptors. Up to 250 µM, NF272 showed no cytotoxicity in MTT cell viability assays in 1321N1, HEK293, and OVCAR-3 cells. Further, NF272 was able to inhibit the ATP-induced calcium signal in OVCAR-3 cells demonstrated to express P2Y2 receptors. In conclusion, NF272 is a competitive but non-selective P2Y2 receptor antagonist with 14-fold higher potency than suramin lacking cytotoxic effects. Therefore, NF272 may serve as a lead structure for further development of P2Y2 receptor antagonists.

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.

Significant Discovery of Tetrahydrothieno[3,2-c]pyridine-2-carboxamide Analogs as Potent P2Y12 Receptor Antagonists.

A series of analogs containing tetrahydrothieno[3,2-c]pyridine-2-carboxamide as a building block with numerous alicyclic and aromatic amines were synthesized. All analogs were characterized by spectral analysis and evaluated for their in vitro antiplatelet activity. 4-Fluorophenyl amide derivatives (compounds 8-11) have been found to be most active in the series with respect to prasugrel and aspirin, a third generation antiplatelet agents (P2Y12 receptor antagonists). Docking study also manifested the admirable binding mode of in vitro active compounds 10 and 11 with the target protein. The results may provide a new perception for future pharmacophore with simple design strategy and avoid tedious synthesis of clopidogrel and prasugrel.

A novel composition of ticagrelor by solid dispersion technique for increasing solubility and intestinal permeability.

The aim of this study is to improve the bioavailability of ticagrelor, BCS class 4 drug, using solid dispersion technique, and to evaluate the potential of ticagrelor loaded-solid dispersion, as a new formulation. The solid dispersion formulation was prepared via solvent evaporation method using ethanol. TPGS and Neusilin® US2 selected via screening studies were used for preparing formulation. The results of scanning electron microscopy, differential scanning calorimetry and powder X-ray diffraction showed that the crystallinity of the ticagrelor was completely transformed to an amorphous form and maintained in the solid dispersion formulation. The released amount of the optimized solid dispersion significantly increased by 2.2- and 34-fold in comparison with physical mixture (Ticagrelor:TPGS:Neusilin® US2 = 1:2:2, w/w/w) and commercial product (Brilinta®) in distilled water at 90 min, respectively. The absorptive permeability was improved (1.4-fold) and the efflux ratio was decreased (0.45-fold) by formulation containing TPGS acting as a P-gp inhibitor compared to pure drug. The solid dispersion formulation improved the peak plasma concentration (Cmax) and relative bioavailability compared to that of pure drug as 238.09 ±â€¯25.96% and 219.78 ±â€¯36.33%, respectively, after oral administration in rats. Thus, we successfully prepared the solid dispersion formulation for enhancing oral bioavailability of ticagrelor, and then this formulation would be recommended as a practical oral pharmaceutical product.

Design, synthesis, and biological evaluation of 2-(phenoxyaryl)-3-urea derivatives as novel P2Y1 receptor antagonists.

A novel series of 2-(phenoxyaryl)-3-urea derivatives were designed, synthesized, and biologically evaluated for their anti-thrombotic activity. Most of compounds exhibited good inhibition against P2Y1 receptor. Among them, three compounds 11, 12, and 13 demonstrated good P2Y1 receptor antagonistic potency in vitro (IC50 = 0.62 µM, 0.82 µM, and 0.21 µM, respectively). In antiplatelet aggregation study, four compounds 2, 3, 9, and 13 showed good antiplatelet activity. The possible binding modes of compounds with P2Y1 receptor were also explored by molecular docking simulation. The docking studies demonstrated that compound 13 interacted well with Phe119 through hydrophobic interaction and modestly improved the P2Y1 receptor antagonistic activity, making it justifiable for further investigation.

Designing Natural Product Hybrids Bearing Triple Antiplatelet Profile and Evaluating Their Human Plasma Stability.

Cardiovascular diseases (CVDs) are becoming major contributors to the burden of disease due to genetic and environmental factors. Despite current standard oral care, cardiovascular risk remains relatively high. A triple antiplatelet therapy with a cyclooxygenase-1 (COX-1) inhibitor, a P2Y12 receptor antagonist, and a protease-activated receptor-1 (PAR-1) antagonist has been established in the secondary prevention of atherothrombosis in patients with acute myocardial infraction and in those with peripheral artery disease. However, due to the combinatorial use of three different drugs, patients receiving this triple therapy are exposed to enhanced risk of bleeding. Conforming to polypharmacology principles, the discovery of a single compound that can simultaneously block the three platelet activation pathways (PAR-1, P2Y12, and COX-1) is of importance. Natural products have served as an inexhaustible source of bioactive compounds presenting a diverse pharmaceutical profile, including anti-inflammatory, antioxidant, anticancer, and antithrombotic activity. Indeed, principal component analysis indicated that natural products have the potential to inhibit the three aforementioned pathways, though existed reports refer to single inhibition mechanism on specific receptor(s) implicated in platelet activation. We thus set out to explore possibilities that take advantage of this potential of natural products and shape the basis to produce novel compounds that could simultaneously target PAR-1, P2Y12, and COX-1 platelet activation pathways. Polyunsaturated fatty acids (PUFAs) have multiple effects leading to improvements in blood pressure and cardiac function and arterial compliance. A promising approach to achieve the desirable goal is the bioconjugation of natural products with PUFAs. Herein, we describe the principles that should be followed to develop molecular hybrids bearing triple antiplatelet activity profile.

Salvianolic acids from antithrombotic Traditional Chinese Medicine Danshen are antagonists of human P2Y1 and P2Y12 receptors.

Many hemorheologic Traditional Chinese Medicines (TCMs) that are widely-used clinically lack molecular mechanisms of action. We hypothesized that some of the active components of hemorheologic TCMs may function through targeting prothrombotic P2Y1 and/or P2Y12 receptors. The interactions between 253 antithrombotic compounds from TCM and these two G protein-coupled P2Y receptors were evaluated using virtual screening. Eleven highly ranked hits were further tested in radioligand binding and functional assays. Among these compounds, salvianolic acid A and C antagonized the activity of both P2Y1 and P2Y12 receptors in the low µM range, while salvianolic acid B antagonized the P2Y12 receptor. These three salvianolic acids are the major active components of the broadly-used hemorheologic TCM Danshen (Salvia militorrhiza), the antithrombotic molecular mechanisms of which were largely unknown. Thus, the combination of virtual screening and experimental validation identified potential mechanisms of action of multicomponent drugs that are already employed clinically.

Tools and drugs for uracil nucleotide-activated P2Y receptors.

P2Y receptors (P2YRs) are a family of G protein-coupled receptors activated by extracellular nucleotides. Physiological P2YR agonists include purine and pyrimidine nucleoside di- and triphosphates, such as ATP, ADP, UTP, UDP, nucleotide sugars, and dinucleotides. Eight subtypes exist, P2Y1, P2Y2, P2Y4, P2Y6, P2Y11, P2Y12, P2Y13, and P2Y14, which represent current or potential future drug targets. Here we provide a comprehensive overview of ligands for the subgroup of the P2YR family that is activated by uracil nucleotides: P2Y2 (UTP, also ATP and dinucleotides), P2Y4 (UTP), P2Y6 (UDP), and P2Y14 (UDP, UDP-glucose, UDP-galactose). The physiological agonists are metabolically unstable due to their fast hydrolysis by ectonucleotidases. A number of agonists with increased potency, subtype-selectivity and/or enzymatic stability have been developed in recent years. Useful P2Y2R agonists include MRS2698 (6-01, highly selective) and PSB-1114 (6-05, increased metabolic stability). A potent and selective P2Y2R antagonist is AR-C118925 (10-01). For studies of the P2Y4R, MRS4062 (3-15) may be used as a selective agonist, while PSB-16133 (10-06) is a selective antagonist. Several potent P2Y6R agonists have been developed including 5-methoxyuridine 5'-O-((Rp)α-boranodiphosphate) (6-12), PSB-0474 (3-11), and MRS2693 (3-26). The isocyanate MRS2578 (10-08) is used as a selective P2Y6R antagonist, although its reactivity and low water-solubility are limiting. With MRS2905 (6-08), a potent and metabolically stable P2Y14R agonist is available, while PPTN (10-14) represents a potent and selective P2Y14R antagonist. The radioligand [3H]UDP can be used to label P2Y14Rs. In addition, several fluorescent probes have been developed. Uracil nucleotide-activated P2YRs show great potential as drug targets, especially in inflammation, cancer, cardiovascular and neurodegenerative diseases.

Demystifying P2Y1 Receptor Ligand Recognition through Docking and Molecular Dynamics Analyses.

We performed a molecular modeling analysis of 100 nucleotide-like bisphosphates and 46 non-nucleotide arylurea derivatives previously reported as P2Y1R binders using the recently solved hP2Y1R structures. We initially docked the compounds at the X-ray structures and identified the binding modes of representative compounds highlighting key patterns in the structure-activity relationship (SAR). We subsequently subjected receptor complexes with selected key agonists (2MeSADP and MRS2268) and antagonists (MRS2500 and BPTU) to membrane molecular dynamics (MD) simulations (at least 200 ns run in triplicate, simulation time 0.6-1.6 µs per ligand system) while considering alternative protonation states of nucleotides. Comparing the temporal evolution of the ligand-protein interaction patterns with available site-directed mutagenesis (SDM) data and P2Y1R apo state simulation provided further SAR insights and suggested reasonable explanations for loss/gain of binding affinity as well as the most relevant charged species for nucleotide ligands. The MD analysis also predicted local conformational changes required for the receptor inactive state to accommodate nucleotide agonists.

From UTP to AR-C118925, the discovery of a potent non nucleotide antagonist of the P2Y2 receptor.

The G protein-coupled P2Y2 receptor, activated by ATP and UTP has been reported as a potential drug target for a wide range of important clinical conditions, such as tumor metastasis, kidney disorders, and in the treatment of inflammatory conditions. However, pharmacological studies on this receptor have been impeded by the limited reported availability of stable, potent and selective P2Y2R antagonists. This article describes the design and synthesis of AR-C118925, a potent and selective non-nucleotide antagonist of the P2Y2 receptor discovered using the endogenous P2Y2R agonist UTP as the chemical starting point.

Identification of novel selective P2Y6 receptor antagonists by high-throughput screening assay.

AIMS: The P2Y6 nucleotide receptor is widely involved in inflammatory responses, and is a promising molecular target for the treatment of inflammatory diseases. Although several P2Y6 receptor antagonists have been developed and evaluated thus far, none has successfully been developed into a therapeutic drug. In this study, we explored new promising compounds that inhibit the human P2Y6 receptor. MAIN METHODS: High-throughput screening (HTS) was used to study the effects of various compounds on human P2Y6 receptors expressed in 1321N1 human astrocytoma cells by monitoring intracellular Ca2+ concentration ([Ca2+]i) levels using an FDSS7000 real-time fluorescence detector. IL-8 concentration was measured by enzyme-linked immunosorbent assay. KEY FINDINGS: Among structurally diverse chemical libraries totalling 141,700 compounds, 43 compounds with an inhibitory activity against the P2Y6 receptor were identified. Further studies using a dose-response assay, receptor selectivity assay, and chemokine measurement assay revealed the selective P2Y6 receptor inhibitor TIM-38, which inhibited UDP-induced [Ca2+]i elevation in a dose-dependent manner. TIM-38 had an IC50 value of 4.3µM and inhibited P2Y6 without affecting the response induced by four other human P2Y or muscarinic receptors. In addition, TIM-38 inhibited UDP-induced interleukin-8 release in a dose-dependent manner without affecting releases caused by other stimulus such as interleukin-1ß or tumour necrosis factor-α. Analyses of TIM-38 derivatives revealed that the nitro moiety is vital to P2Y6 receptor inhibition. SIGNIFICANCE: TIM-38 acts as a novel structural antagonist of P2Y6 receptor and may be a good lead compound for developing a P2Y6 receptor-targeted anti-inflammatory drug.

Investigating the binding mechanism of novel 6-aminonicotinate-based antagonists with P2Y12 by 3D-QSAR, docking and molecular dynamics simulations.

P2Y12 receptor is an attractive target for the anti-platelet therapies, treating various thrombotic diseases. In this work, a total of 107 6-aminonicotinate-based compounds as potent P2Y12 antagonists were studies by a molecular modeling study combining three-dimensional quantitative structure-activity relationship (3D-QSAR), molecular docking and molecular dynamics (MD) simulations to explore the decisive binding conformations of these antagonists with P2Y12 and the structural features for the activity. The optimum CoMFA and CoMSIA models identified satisfactory robustness and good predictive ability, with R2 = .983, q2 = .805, [Formula: see text] = .881 for CoMFA model, and R2 = .935, q2 = .762, [Formula: see text] = .690 for CoMSIA model, respectively. The probable binding modes of compounds and key amino acid residues were revealed by molecular docking. MD simulations and MM/GBSA free energy calculations were further performed to validate the rationality of docking results and to compare the binding modes of several compound pairs with different activities, and the key residues (Val102, Tyr105, Tyr109, His187, Val190, Asn191, Phe252, His253, Arg256, Tyr259, Thr260, Val279, and Lys280) for the higher activity were pointed out. The binding energy decomposition indicated that the hydrophobic and hydrogen bond interactions play important roles for the binding of compounds to P2Y12. We hope these results could be helpful in design of potent and selective P2Y12 antagonists.