Semaphorin3A released from human dental pulp cells inhibits the increase in interleukin-6 and CXC chemokine ligand 10 production induced by tumor necrosis factor-α through suppression of nuclear factor-κB activation

Human dental pulp cells (HDPCs) play an important role in pulpitis. Semaphorin3A (Sema3A), which is an axon guidance molecule, is a member of the secretory semaphorin family. Recently, Sema3A has been reported to be an osteoprotective factor and to be involved in the immune response. However, the role of Sema3A in dental pulp inflammation remains unknown. The aim of this study was to reveal the existence of Sema3A in human dental pulp tissue and the effect of Sema3A which is released from tumor necrosis factor (TNF)-α-stimulated HDPCs on production of proinflammatory cytokines, such as interleukin (IL)-6 and CXC chemokine ligand 10 (CXCL10), from HDPCs stimulated with TNF-α. Sema3A was detected in inflamed pulp as compared to normal pulp. HDPCs expressed Neuropilin-1(Nrp1) which is Sema3A receptor. TNF-α increased the levels of IL-6 and CXCL10 in HDPCs in time-dependent manner. Sema3A inhibited production of these two cytokines from TNF-α-stimulated HDPCs. TNF-α induced soluble Sema3A production from HDPCs. Moreover, antibody-based neutralization of Sema3A further promoted production of IL-6 and CXCL10 from TNF-α-stimulated HDPCs. Sema3A inhibited nuclear factor (NF)-κB P65 phosphorylation and inhibitor κBα degradation in TNF-α-stimulated HDPCs. These results indicated that Sema3A is induced in human dental pulp, and TNF-α acts on HDPCs to produce Sema3A, which partially inhibits the increase in IL-6 and CXCL10 production induced by TNF-α, and that the inhibition leads to suppression of NF-κB activation. Therefore, it is suggested that Sema3A may regulate inflammation in dental pulp and be novel antiinflammatory target molecule for pulpitis.     

N-alkyl-[1,1′-biphenyl]-2-sulfonamide derivatives as novel broad spectrum anti-epileptic drugs with efficacy equivalent to that of sodium valproate

In order to develop phenyl sulfonamides as a novel class of anti-epileptic drugs (AED) for both general and partial seizure, we initiated in vivo screening of our chemical library in the mice MES and sc-PTZ models and found compounds 1 and 2 as lead compounds. Optimization of 1 and 2 led to the discovery of compound 21, which showed potent anticonvulsant effect in MES, scPTZ and rat amygdala kindling models. These findings indicate that compound 21 could be a useful new broad spectrum AED like sodium valproate and provide an opportunity to struggle current therapy-resistant epilepsy.     

Discovery of the imidazo[1,5-a][1,2,4]-triazolo[1,5-d][1,4]benzodiazepine scaffold as a novel,potent and selective GABAA α5 inverse agonist series

Through iterative design cycles we have discovered a number of novel new classes where the imidazo[1,5-a][1,2,4]-triazolo[1,5-d][1,4]benzodiazepine was deemed the most promising GABA_A α5 inverse agonist class with potential for cognitive enhancement. This class combines a modest subtype binding selectivity with inverse agonism and has the most favourable molecular properties for further lead optimisation towards a central nervous system (CNS) acting medicine.     

Synthesis and in vitro evaluations of 6-(hetero)-aryl-imidazo[1,2-b]pyridazine-3-sulfonamide’s as an inhibitor of TNF-α production

Tumor necrosis factor-α is an important pro-inflammatory cytokine having a key role in hosts defensive process of immune systems and its over expression led to a diverse range of inflammatory diseases such as Rheumatoid arthritis, Cronh’s disease, psoriasis, etc. This paper describes our medicinal chemistry efforts on imidazo[1,2-b]pyridazine scaffold: design, synthesis and biological evaluation. By the introducing sulfonamide functionality at 3 positions and substituting 6 positions with (hetero)-aryl groups’, a small library of compounds was prepared. All synthesized compounds were screened for lipopolysaccharide (LPS) mediated TNF-α production inhibitory activity. Biological data revealed that the majority of the compounds of this series showed moderate to potent TNF-α production inhibitory activity. Compound 5u and 5v are the most potent compounds from the series with activity of IC₅₀?=?0.5?µM and 0.3?µM respectively. A short SAR demonstrates that 3-sulfonyl-4-arylpiperidine-4-carbonitrile moiety on imidazo[1,2-b]pyridazine showed better activity compared to the 3-(4-aryllpiperazin-1-yl) sulfonyl) in hPBMC assay. The molecular modeling studies revealed that the potent TNF-α production inhibitory activity 5v due to the extra stability of complex because of an extra pi-pi (π-π) stacking, hydrogen-bonding interactions.     

Synthesis and preclinical characterization of 1-(6′-deoxy-6′-[18F]fluoro-β-d-allofuranosyl)-2-nitroimidazole (β-6′-[18F]FAZAL) as a positron emission tomography radiotracer to assess tumor hypoxia

Positron emission tomography (PET) using fluorine-18 (¹⁸F)-labeled 2-nitroimidazole radiotracers has proven useful for assessment of tumor oxygenation. However, the passive diffusion-driven cellular uptake of currently available radiotracers results in slow kinetics and low tumor-to-background ratios. With the aim to develop a compound that is actively transported into cells, 1-(6′-deoxy-6′-[¹⁸F]fluoro-β-d-allofuranosyl)-2-nitroimidazole (β-[¹⁸F]1), a putative nucleoside transporter substrate, was synthetized by nucleophilic [¹⁸F]fluoride substitution of an acetyl protected labeling precursor with a tosylate leaving group (β-6) in a final radiochemical yield of 12 ± 8% (n = 10, based on [¹⁸F]fluoride starting activity) in a total synthesis time of 60 min with a specific activity at end of synthesis of 218 ± 58 GBq/μmol (n = 10). Both radiolabeling precursor β-6 and unlabeled reference compound β-1 were prepared in multistep syntheses starting from 1,2:5,6-di-O-isopropylidene-α-d-allofuranose. In vitro experiments demonstrated an interaction of β-1 with SLC29A1 and SLC28A1/2/3 nucleoside transporter as well as hypoxia specific retention of β-[¹⁸F]1 in tumor cell lines. In biodistribution studies in healthy mice β-[¹⁸F]1 showed homogenous tissue distribution and excellent metabolic stability, which was unaffected by tissue oxygenation. PET studies in tumor bearing mice showed tumor-to-muscle ratios of 2.13 ± 0.22 (n = 4) at 2 h after administration of β-[¹⁸F]1. In ex vivo autoradiography experiments β-[¹⁸F]1 distribution closely matched staining with the hypoxia marker pimonidazole. In conclusion, β-[¹⁸F]1 shows potential as PET hypoxia radiotracer which merits further investigation.     

4-([1,2,4]Triazolo[1,5-a]pyridin-6-yl)-5(3)-(6-methylpyridin-2-yl)imidazole and -pyrazole derivatives as potent and selective inhibitors of transforming growth factor-β type I receptor kinase

A series of 4-([1,2,4]triazolo[1,5-a]pyridin-6-yl)-5(3)-(6-methylpyridin-2-yl)imidazoles and -pyrazoles 14a–c, 15a–c, 16a, 16b, 19a–d, 21a, and 21b has been synthesized and evaluated for their ALK5 inhibitory activity in an enzyme assay and in a cell-based luciferase reporter assay. Among them, the pyrazole derivative 21b inhibited ALK5 phosphorylation with an IC₅₀ value of 0.018 μM and showed 95% inhibition at 0.03 μM in a luciferase reporter assay using HaCaT cells permanently transfected with p3TP-luc reporter construct. The 21b showed a high selectivity index of 284 against p38α MAP kinase. The binding pose of 21b generated by docking analysis reveals that it fits well into the ATP binding cavity of ALK5 by forming several hydrogen bond interactions.     

5-(5-(6-[(11)C]methyl-3,6-diazabicyclo[3.2.0]heptan-3-yl)pyridin-2-yl)-1H-indole as a potential PET radioligand for imaging cerebral α7-nAChR in mice

The radiosynthesis and in vivo evaluation of 5-(5-(6-[(11)C]methyl-3,6-diazabicyclo[3.2.0]heptan-3-yl)pyridin-2-yl)-1H-indole [(11)C]rac-(1), a potential PET tracer for α7 nicotinic acetylcholine receptors (α7-nAChR), are described. Syntheses of the nonradioactive standard rac-1 and corresponding desmethyl precursor 7 were achieved in several reaction steps. Radiomethylation of 7 with [(11)C]CH(3)I afforded [(11)C]rac-1 in an average radiochemical yield of 30 ± 5% (n=5) with high radiochemical purity and an average specific radioactivity of 444 ± 74 GBq/μmol (n=5). The total synthesis time was 30 min from end-of-bombardment. Biodistribution studies in mice showed that [(11)C]rac-1 penetrates the blood-brain barrier and specifically labels neuronal α7-nAChRs.     

Discovery of 5-(2-chloro-4′-(1H-imidazol-1-yl)-[1,1′-biphenyl]-4-yl)-1H-tetrazole as potent and orally efficacious S-nitrosoglutathione reductase (GSNOR) inhibitors for the potential treatment of COPD

Endogenous nitrosothiols (SNOs) including S-nitrosoglutathione (GSNO) serve as reservoir for bioavailable nitric oxide (NO) and mediate NO-based signaling, inflammatory status and smooth muscle function in the lung. GSNOR inhibition increases pulmonary GSNO and induces bronchodilation while reducing inflammation in lung diseases. In this letter, design, synthesis and structure–activity relationships (SAR) of novel imidazole-biaryl-tetrazole based GSNOR inhibitors are described. Many potent inhibitors (30, 39, 41, 42, 44, 45 and 58) were identified with low nanomolar activity (IC₅₀s: <15?nM) along with adequate metabolic stability. Lead compounds 30 and 58 exhibited good exposure and oral bioavailability in mouse pharmacokinetic (PK) study. Compound 30 was selected for further profiling and revealed comparable mouse and rat GSNOR potency, high selectivity against alcohol dehydrogenase (ADH) and carbonyl reductase (CBR1) family of enzymes, low efflux ratio and permeability in PAMPA, a high permeability in CALU-3 assay, significantly low hERG activity and minimal off-target activity. Further, an in vivo efficacy of compound 30 is disclosed in cigarette smoke (CS) induced mouse model for COPD.