Identification of Riluzole derivatives as novel calmodulin inhibitors with neuroprotective activity by a joint synthesis, biosensor, and computational guided strategy.

The development of new molecules for the treatment of calmodulin related cardiovascular or neurodegenerative diseases is an interesting goal. In this work, we introduce a novel strategy with four main steps: (1) chemical synthesis of target molecules, (2) Förster Resonance Energy Transfer (FRET) biosensor development and in vitro biological assay of new derivatives, (3) Cheminformatics models development and in vivo activity prediction, and (4) Docking studies. This strategy is illustrated with a case study. Firstly, a series of 4-substituted Riluzole derivatives 1-3 were synthetized through a strategy that involves the construction of the 4-bromoriluzole framework and its further functionalization via palladium catalysis or organolithium chemistry. Next, a FRET biosensor for monitoring Ca2+-dependent CaM-ligands interactions has been developed and used for the in vitro assay of Riluzole derivatives. In particular, the best inhibition (80%) was observed for 4-methoxyphenylriluzole 2b. Besides, we trained and validated a new Networks Invariant, Information Fusion, Perturbation Theory, and Machine Learning (NIFPTML) model for predicting probability profiles of in vivo biological activity parameters in different regions of the brain. Next, we used this model to predict the in vivo activity of the compounds experimentally studied in vitro. Last, docking study conducted on Riluzole and its derivatives has provided valuable insights into their binding conformations with the target protein, involving calmodulin and the SK4 channel. This new combined strategy may be useful to reduce assay costs (animals, materials, time, and human resources) in the drug discovery process of calmodulin inhibitors.

Identification of 6-hydroxy-5-phenyl sulfonylpyrimidin-4(1H)-one APJ receptor agonists.

Heart failure (HF) treatment remains a critical unmet medical need. Studies in normal healthy volunteers and HF patients have shown that [Pyr1]apelin-13, the endogenous ligand for the APJ receptor, improves cardiac function. However, the short half-life of [Pyr1]apelin-13 and the need for intravenous administration have limited the therapeutic potential for chronic use. We sought to identify potent, small-molecule APJ agonists with improved pharmaceutical properties to enable oral dosing in clinical studies. In this manuscript, we describe the identification of a series of pyrimidinone sulfones as a structurally differentiated series to the clinical lead (compound 1). Optimization of the sulfone series for potency, metabolic stability and oral bioavailability led to the identification of compound 22, which showed comparable APJ potency to [Pyr1]apelin-13 and exhibited an acceptable pharmacokinetic profile to advance to the acute hemodynamic rat model.

Human iPSC modeling of heart disease for drug development.

Human induced pluripotent stem cells (hiPSCs) have emerged as a promising platform for pharmacogenomics and drug development. In cardiology, they make it possible to produce unlimited numbers of patient-specific human cells that reproduce hallmark features of heart disease in the culture dish. Their potential applications include the discovery of mechanism-specific therapeutics, the evaluation of safety and efficacy in a human context before a drug candidate reaches patients, and the stratification of patients for clinical trials. Although this new technology has the potential to revolutionize drug discovery, translational hurdles have hindered its widespread adoption for pharmaceutical development. Here we discuss recent progress in overcoming these hurdles that should facilitate the use of hiPSCs to develop new medicines and individualize therapies for heart disease.

The first 3500 years of aspirin history from its roots - A concise summary.

Aspirin is currently the most widely used drug worldwide, and has been clearly one of the most important pharmacological achievements of the twentieth century. Historians of medicine have traced its birth in 1897, but the fascinating history of aspirin actually dates back >3500 years, when willow bark was used as a painkiller and antipyretic by Sumerians and Egyptians, and then by great physicians from ancient Greece and Rome. The modern history of aspirin precursors, salicylates, began in 1763 with Reverend Stone - who first described their antipyretic effects - and continued in the 19th century with many researchers involved in their extraction and chemical synthesis. Bayer chemist Felix Hoffmann synthesized aspirin in 1897, and 70 years later the pharmacologist John Vane elucidated its mechanism of action in inhibiting prostaglandin production. Originally used as an antipyretic and anti-inflammatory drug, aspirin then became, for its antiplatelet properties, a milestone in preventing cardiovascular and cerebrovascular diseases. The aspirin story continues today with the growing evidence of its chemopreventive effect against colorectal and other types of cancer, now awaiting the results of ongoing primary prevention trials in this setting. This concise review revisits the history of aspirin with a focus on its most remote origins.

Therapeutic potential of quercetin as a cardiovascular agent.

Flavonoids are integral components of various vegetation and in foods; consequently, they represent an inevitable part of the diet. Historical and epidemiological proof recommend that diet plans consisting of flavonoids such as quercetin have positive health benefits, especially on the heart. Flavonoids have been proven to be active against hypertension, inflammation, diabetes and vascular diseases. Quercetin exhibits significant heart related benefits as inhibition of LDL oxidation, endothelium-independent vasodilator effects, reduction of adhesion molecules and other inflammatory markers, the protective effect on nitric oxide and endothelial function under conditions of oxidative stress, prevention of neuronal oxidative and inflammatory damage and platelet antiaggregant effects. Searching for experimental evidence to validate the cardioprotective effects of quercetin, we review here the recent detailed in vivo studies. Quercetin and its derivatives lead to an enhancement in heart features, indicating the prospective for quercetin to be used therapeutically in the treatment of cardiac diseases. Several evidence-based studies suggest mechanisms to observe cardiovascular diseases such as aging effects, hypertension, angiotensin-converting enzyme activity and endothelial-dependent and independent functions. Different animal models including human are also used to elucidate the in vivo role of quercetin in cardiovascular diseases. The role of quercetin and its derivatives may go beyond their existence in food and has potential as a lead molecule in drug development programs.

An anti-PDGFRß aptamer for selective delivery of small therapeutic peptide to cardiac cells.

Small therapeutic peptides represent a promising field for the treatment of pathologies such as cardiac diseases. However, the lack of proper target-selective carriers hampers their translation towards a potential clinical application. Aptamers are cell-specific carriers that bind with high affinity to their specific target. However, some limitations on their conjugation to small peptides and the functionality of the resulting aptamer-peptide chimera exist. Here, we generated a novel aptamer-peptide chimera through conjugation of the PDGFRß-targeting Gint4.T aptamer to MP, a small mimetic peptide that via targeting of the Cavß2 subunit of the L-type calcium channel (LTCC) can recover myocardial function in pathological heart conditions associated with defective LTCC function. The conjugation reaction was performed by click chemistry in the presence of N,N,N',N',N"-pentamethyldiethylenetriamine as a Cu (I) stabilizing agent in a DMSO-free aqueous buffer. When administered to cardiac cells, the Gint4.T-MP aptamer-peptide chimera was successfully internalized in cells, allowing the functional targeting of MP to LTCC. This approach represents the first example of the use of an internalizing aptamer for selective delivery of a small therapeutic peptide to cardiac cells.

An Aza resveratrol-chalcone derivative 6b protects mice against diabetic cardiomyopathy by alleviating inflammation and oxidative stress.

Inflammation and oxidative stress play a crucial role in the development of diabetic cardiomyopathy (DCM). We previously had synthesized an Aza resveratrol-chalcone derivative 6b, of which effectively suppressing lipopolysaccharide (LPS)-induced inflammatory response in macrophages. This study aimed to investigate the potential protective effect of 6b on DCM and underlying mechanism. In H9c2 myocardial cells, 6b potently decreased high glucose (HG)-induced cell fibrosis, hypertrophy and apoptosis, alleviating inflammatory response and oxidant stress. In STZ-induced type 1 diabetic mice (STZ-DM1), orally administration with 6b for 16 weeks significantly attenuated cardiac hypertrophy, apoptosis and fibrosis. The expression of inflammatory cytokines and oxidative stress biomarkers was also suppressed by 6b distinctly, without affecting blood glucose and body weight. The anti-inflammatory and antioxidative activities of 6b were mechanistic associated with nuclear factor-kappa B (NF-κB) nucleus entry blockage and Nrf2 activation both in vitro and in vivo. The results indicated that 6b can be a promising cardioprotective agent in treatment of DCM via inhibiting inflammation and alleviating oxidative stress. This study also validated the important role of NF-κB and Nrf2 taken in the pathogenesis of DCM, which could be therapeutic targets for diabetic comorbidities.

Nucleoligands-repurposing G Protein-coupled Receptor Ligands to Modulate Nuclear-localized G Protein-coupled Receptors in the Cardiovascular System.

There is significant evidence that internal pools of G protein-coupled receptors (GPCRs) exist and may be affected by both endogenous signaling molecules and hydrophobic pharmaceutical ligands, once assumed to only affect cell surface versions of these receptors. Here, we discuss evidence that the biology of nuclear GPCRs in particular is complex, rich, and highly interactive with GPCR signaling from the cell surface. Caging existing GPCR ligands may be an excellent means of further stratifying the phenotypic effects of known pharmacophores such as ß-adrenergic, angiotensin II, and type B endothelin receptor ligands in the cardiovascular system. We describe some synthetic strategies we have used to design ligands to go from in cellulo to in vivo experiments. We also consider how surface and intracellular GPCR signaling might be integrated and ways to dissect this. If they could be selectively targeted, nuclear GPCRs and their associated nucleoligands would represent a completely novel area for exploration by Pharma.

Synthetic Modification within the "RPRL" Region of Apelin Peptides: Impact on Cardiovascular Activity and Stability to Neprilysin and Plasma Degradation.

Apelin is an important mammalian peptide hormone with a range of physiological roles, especially in the cardiovascular system. The apelinergic system is a promising target for treatment of disease, but this remains to be realized due to rapid proteolysis of apelin-derived peptides by proteases, including neprilysin (NEP). The synthetic analogues modified within the NEP degradation site ("RPRL" motif) showed improved in vitro proteolytic stability while maintaining receptor-binding affinities, with three candidate peptides retaining full cardiovascular activities for potential therapeutic application. Many such analogues proved physiologically inactive even with relatively conservative modifications, highlighting the importance of this region for full agonist activity of this peptide hormone.

Synthetic Approaches to the New Drugs Approved During 2015.

New drugs introduced to the market every year represent privileged structures for particular biological targets. These new chemical entities (NCEs) provide insight into molecular recognition while serving as leads for designing future new drugs. This annual review describes the most likely process-scale synthetic approaches to 29 new chemical entities (NCEs) that were approved for the first time in 2015.

CDDO and Its Role in Chronic Diseases.

There has been a continued interest in translational research focused on both natural products and manipulation of functional groups on these compounds to create novel derivatives with higher desired activities. Oleanolic acid, a component of traditional Chinese medicine used in hepatitis therapy, was modified by chemical processes to form 2-cyano-3,12-dioxoolean-1,9-dien-28-oic acid (CDDO). This modification increased anti-inflammatory activity significantly and additional functional groups on the CDDO backbone have shown promise in treating conditions ranging from kidney disease to obesity to diabetes. CDDO's therapeutic effect is due to its upregulation of the master antioxidant transcription factor Nuclear factor erythroid 2-related factor 2 (Nrf2) through conformational change of Nrf2-repressing, Kelch-like erythroid cell-derived protein with CNC homology-associated protein 1 (Keap1) and multiple animal and human studies have verified subsequent activation of Nrf2-controlled antioxidant genes via upstream Antioxidant Response Element (ARE) regions. At the present time, positive results have been obtained in the laboratory and clinical trials with CDDO derivatives treating conditions such as lung injury, inflammation and chronic kidney disease. However, clinical trials for cancer and cardiovascular disease have not shown equally positive results and further exploration of CDDO and its derivatives is needed to put these shortcomings into context for the purpose of future therapeutic modalities.

Benzothiazole Sulfinate: a Water-Soluble and Slow-Releasing Sulfur Dioxide Donor.

Sulfur dioxide (SO2) has long been considered a toxic environmental pollutant and byproduct of industrial processing. Recently it has become evident that SO2 may also have regulatory functions in mammalian pulmonary systems. However, the study of these effects has proven to be challenging due to the difficulty in administering SO2 in a reliable manner. In this work, we report the discovery of a new pH-dependent and water-soluble SO2 donor, benzothiazole sulfinate (BTS). We have found BTS to have slow and sustained SO2 release at physiological pH. Additionally, we have explored its vasorelaxation properties as compared to the authentic SO2 gas solutions. The slow release of BTS should make it a useful tool for the study of endogenously generated SO2.

An Efficient Chemical Synthesis of Scutellarein: An in Vivo Metabolite of Scutellarin.

Scutellarein (2), which is an important in vivo metabolite of scutellarin (1), was synthesized from 3,4,5-trimethoxyphenol (3) in high yield in four steps. This strategy relies on acetylation, aldolization, cyclization and hydrolysis reactions, respectively.

Chemical Structure-Related Drug-Like Criteria of Global Approved Drugs.

The chemical structure of a drug determines its physicochemical properties, further determines its ADME/Tox properties, and ultimately affects its pharmacological activity. Medicinal chemists can regulate the pharmacological activity of drug molecules by modifying their structure. Ring systems and functional groups are important components of a drug. The proportion of non-hydrocarbon atoms among non-hydrogen atoms reflects the heavy atoms proportion of a drug. The three factors have considerable potential for the assessment of the drug-like properties of organic molecules. However, to the best of our knowledge, there have been no studies to systematically analyze the simultaneous effects of the number of aromatic and non-aromatic rings, the number of some special functional groups and the proportion of heavy atoms on the drug-like properties of an organic molecule. To this end, the numbers of aromatic and non-aromatic rings, the numbers of some special functional groups and the heavy atoms proportion of 6891 global approved small drugs have been comprehensively analyzed. We first uncovered three important structure-related criteria closely related to drug-likeness, namely: (1) the best numbers of aromatic and non-aromatic rings are 2 and 1, respectively; (2) the best functional groups of candidate drugs are usually -OH, -COOR and -COOH in turn, but not -CONHOH, -SH, -CHO and -SO3H. In addition, the -F functional group is beneficial to CNS drugs, and -NH2 functional group is beneficial to anti-infective drugs and anti-cancer drugs; (3) the best R value intervals of candidate drugs are in the range of 0.05-0.50 (preferably 0.10-0.35), and R value of the candidate CNS drugs should be as small as possible in this interval. We envision that the three chemical structure-related criteria may be applicable in a prospective manner for the identification of novel candidate drugs and will provide a theoretical foundation for designing new chemical entities with good drug-like properties.

Improved oral absorption of cilostazol via sulfonate salt formation with mesylate and besylate.

OBJECTIVE: Cilostazol is a Biopharmaceutical Classification System class II drug with low solubility and high permeability, so its oral absorption is variable and incomplete. The aim of this study was to prepare two sulfonate salts of cilostazol to increase the dissolution and hence the oral bioavailability of cilostazol. METHODS: Cilostazol mesylate and cilostazol besylate were synthesized from cilostazol by acid addition reaction with methane sulfonic acid and benzene sulfonic acid, respectively. The salt preparations were characterized by nuclear magnetic resonance spectroscopy. The water contents, hygroscopicity, stress stability, and photostability of the two cilostazol salts were also determined. The dissolution profiles in various pH conditions and pharmacokinetic studies in rats were compared with those of cilostazol-free base. RESULTS: The two cilostazol salts exhibited good physicochemical properties, such as nonhygroscopicity, stress stability, and photostability, which make it suitable for the preparation of pharmaceutical formulations. Both cilostazol mesylate and cilostazol besylate showed significantly improved dissolution rate and extent of drug release in the pH range 1.2-6.8 compared to the cilostazol-free base. In addition, after oral administration to rats, cilostazol mesylate and cilostazol besylate showed increases in C max and AUC t of approximately 3.65- and 2.87-fold and 3.88- and 2.94-fold, respectively, compared to cilostazol-free base. CONCLUSION: This study showed that two novel salts of cilostazol, such as cilostazol mesylate and cilostazol besylate, could be used to enhance its oral absorption. The findings warrant further preclinical and clinical studies on cilostazol mesylate and cilostazol besylate at doses lower than the usually recommended dosage, so that it can be established as an alternative to the marketed cilostazol tablet.

Crystal Structure of G Protein-coupled Receptor Kinase 5 in Complex with a Rationally Designed Inhibitor.

G protein-coupled receptor kinases (GRKs) regulate cell signaling by initiating the desensitization of active G protein-coupled receptors. The two most widely expressed GRKs (GRK2 and GRK5) play a role in cardiovascular disease and thus represent important targets for the development of novel therapeutic drugs. In the course of a GRK2 structure-based drug design campaign, one inhibitor (CCG215022) exhibited nanomolar IC50 values against both GRK2 and GRK5 and good selectivity against other closely related kinases such as GRK1 and PKA. Treatment of murine cardiomyocytes with CCG215022 resulted in significantly increased contractility at 20-fold lower concentrations than paroxetine, an inhibitor with more modest selectivity for GRK2. A 2.4 Å crystal structure of the GRK5·CCG215022 complex was determined and revealed that the inhibitor binds in the active site similarly to its parent compound GSK180736A. As designed, its 2-pyridylmethyl amide side chain occupies the hydrophobic subsite of the active site where it forms three additional hydrogen bonds, including one with the catalytic lysine. The overall conformation of the GRK5 kinase domain is similar to that of a previously determined structure of GRK6 in what is proposed to be its active state, but the C-terminal region of the enzyme adopts a distinct conformation. The kinetic properties of site-directed mutants in this region are consistent with the hypothesis that this novel C-terminal structure is representative of the membrane-bound conformation of the enzyme.

Ligustrazine derivatives. Part 8: design, synthesis, and preliminary biological evaluation of novel Ligustrazinyl amides as cardiovascular agents.

A series of novel Ligustrazinyl amides was designed, synthesized and evaluated for their protective effect on the injured vascular endothelial cells. The preliminary results demonstrated that some compounds possessed more potent activities than that of Ligustrazine in stimulating replication of the injured human umbilical vascular endothelial cells (HUVECs) that is damaged by hydrogen peroxide. Among the active compounds, compounds 8i, 8t and 8u exhibited the highest potency with low EC50 values of 0.037, 0.070 and 0.055 mM, respectively. Structure-activity relationships were briefly discussed.

Discovery of potent, selective chymase inhibitors via fragment linking strategies.

Chymase plays an important and diverse role in the homeostasis of a number of cardiovascular processes. Herein, we describe the identification of potent, selective chymase inhibitors, developed using fragment-based, structure-guided linking and optimization techniques. High-concentration biophysical screening methods followed by high-throughput crystallography identified an oxindole fragment bound to the S1 pocket of the protein exhibiting a novel interaction pattern hitherto not observed in chymase inhibitors. X-ray crystallographic structures were used to guide the elaboration/linking of the fragment, ultimately leading to a potent inhibitor that was >100-fold selective over cathepsin G and that mitigated a number of liabilities associated with poor physicochemical properties of the series it was derived from.

Ligustrazine derivatives. Part 6: design, synthesis and evaluation of novel ligustrazinyl acylguanidine derivatives as potential cardiovascular agents.

A series of novel Ligustrazinyl acylguanidines was designed, synthesized and evaluated for their protective effect on injured vascular endothelial cell (ECV-304). The preliminary results demonstrated that some compounds possessed more potent activities than that of Ligustrazine in stimulating replication of the injured endothelial cell. Among the active compounds, compounds 8b, 8f and 8l displayed remarkable antioxidative activity with low EC(50) values of 0.097, 0.059 and 0.094 mM, respectively. Structure-activity relationships were briefly discussed.

Ligustrazine derivatives. Part 4: design, synthesis, and biological evaluation of novel ligustrazine-based stilbene derivatives as potential cardiovascular agents.

A series of novel stilbene derivatives containing ligustrazinyl moiety was designed, synthesized, and assayed for their protective effects on damaged endothelial cells. The results showed that most ligustrazinyl stilbene derivatives exhibited high protective effects on the human umbilical vascular endothelial cells (HUVECs) damaged by hydrogen peroxide in comparison with Ligustrazine. The stilbene derivatives A6, A9, A11, A21, A24, A25, and A27 exhibited high potency with low EC(50) values ranged from 0.0249 µm to 0.0898 mm. Compound A27 displayed EC(50) 0.0249 µm, which is 30,000 times higher than that of Ligustrazine, presenting a most promising lead for further investigation. Structure-activity relationships were briefly discussed.