Synthesis, Biological Evaluation, and Molecular Modeling Studies of New Thiadiazole Derivatives as Potent P2X7 Receptor Inhibitors.

Daniel T G Gonzaga,G Q Pinho,Helena C Castro,Rennan P P Leme,Carlos R Rodrigues,Luiz C S Pinheiro,Murilo L Bello,Caroline R C Reis,Robson X Faria,Lucas V B Hoelz,João C M Mafra,Felipe H Oliveira,Hellen V C M De Souza,N L Von Ranke,Nubia Boechat,Juliana P Salles

doi:10.3389/fchem.2019.00261

Abstract

Twenty new 2-(1H-pyrazol-1-yl)-1,3,4-thiadiazole analogs were synthetized to develop P2X7 receptor (P2X7R) inhibitors. P2X7R inhibition in vitro was evaluated in mouse peritoneal macrophages, HEK-293 cells transfected with hP2X7R (dye uptake assay), and THP-1 cells (IL-1β release assay). The 1-(5-phenyl-1,3,4-thiadiazol-2-yl)-1H-pyrazol-5-amine derivatives 9b, 9c, and 9f, and 2-(3,5-dimethyl-1H-pyrazol-1-yl)-5-(4-fluorophenyl)-1,3,4-thiadiazole (11c) showed inhibitory effects with IC50 values ranging from 16 to 122 nM for reduced P2X7R-mediated dye uptake and 20 to 300 nM for IL-1β release. In addition, the in vitro ADMET profile of the four most potent derivatives was determined to be in acceptable ranges concerning metabolic stability and cytotoxicity. Molecular docking and molecular dynamics simulation studies of the molecular complexes human P2X7R/9f and murine P2X7R/9f indicated the putative intermolecular interactions. Compound 9f showed affinity mainly for the Arg268, Lys377, and Asn266 residues. These results suggest that 2-(1H-pyrazol-1-yl)-1,3,4-thiadiazole analogs may be promising novel P2X7R inhibitors with therapeutic potential.

Highlights

Another important activity associated with P2X7 receptor (P2X7R) is the maturation and release of interleukin-1β (IL-1β), which is a cytokine related to inflammation and pain signaling (Skaper et al, 2010)
The synthesis of a series of novel thiadiazole derivatives targeting P2X7R led to the discovery of potent inhibitors, such as 9f (IC50 = 16 nM)
Derivative 9f showed acceptable in vitro inhibitory action against P2X7R; pharmacokinetic, pharmacodynamic, and toxicological properties in silico; and anti-inflammatory activity in vivo

Summary

INTRODUCTION

Pyrazole (Küçükgüzel and Senkardes, 2015; Faria et al, 2017) and the 1,3,4-thiadiazole derivatives show several biological activities (Hu et al, 2014), including anti-viral (Gan et al, 2017), anti-bacterial (Aggarwal et al, 2014), anti-tumoral (Rai et al, 2015), anti-inflammatory (El-Sehemi et al, 2014), anti-cancer (Raj et al, 2015), anti-convulsant (Raj et al, 2017), anti-depressant (Can et al, 2018), and other effects (Pérez-Fernéndez et al, 2014; Shawali, 2014; Ansari et al, 2017; Karrouchi et al, 2018). Thiadiazole 9f stability was evaluated in liver microsomes from male mice and humans according to Faria et al in 2018 (Faria et al, 2018) Both solutions contained a final protein concentration of 0.5 mg/ml (0.1 M phosphate buffer) at pH 7.4. Three-dimensional models of the human and mouse P2X7Rs (hP2X7R and mP2X7R) with lipid membrane and water molecules, both in apo and in complex with the inhibitor, were used to study the MD of the free (hP2X7RAPO and mP2X7RAPO) and bound (hP2X7R9f and mP2X7R9f) aqueous systems. During the last 150 ns of the MD simulation, the intermolecular hydrogen bond (H-bond) interactions of compound 9f with the amino acids of the hP2X7 and mP2X7 receptors were analyzed This calculation was performed using the G_HBOND program of the GROMACS 5.1.4 package (Abraham et al, 2015). The PYMOL 1.5.0.3 software was used to make the images of the porcupine projections (DeLano, 2002; Delano and Bromberg, 2004; Karasawa and Kawate, 2016)

DISCUSSION

CONCLUSION

ETHICS STATEMENT