ABSTRACT
Inflammatory bowel disease (IBD) is characterized by abnormal immune responses, including elevated proinflammatory cytokines, such as tumor necrosis factor-α (TNFα) and interleukin-6 (IL-6) in the gastrointestinal (GI) tract. This study presents the synthesis and anti-inflammatory evaluation of 2,4,5-trimethylpyridin-3-ol analogues, which exhibit dual inhibition of TNFα- and IL-6-induced inflammation. Analysis using in silico methods, including 3D shape-based target identification, modeling, and docking, identified G protein-coupled estrogen receptor 1 (GPER) as the molecular target for the most effective analogue, 6-26, which exhibits remarkable efficacy in ameliorating inflammation and restoring colonic mucosal integrity. This was further validated by surface plasmon resonance (SPR) assay results, which showed direct binding to GPER, and by the results showing that GPER knockdown abolished the inhibitory effects of 6-26 on TNFα and IL-6 actions. Notably, 6-26 displayed no cytotoxicity, unlike G1 and G15, a well-known GPER agonist and an antagonist, respectively, which induced necroptosis independently of GPER. These findings suggest that the GPER-selective compound 6-26 holds promise as a therapeutic candidate for IBD.
Subject(s)
Inflammatory Bowel Diseases , Receptors, Estrogen , Receptors, G-Protein-Coupled , Receptors, G-Protein-Coupled/antagonists & inhibitors , Receptors, G-Protein-Coupled/metabolism , Receptors, G-Protein-Coupled/agonists , Inflammatory Bowel Diseases/drug therapy , Inflammatory Bowel Diseases/metabolism , Humans , Animals , Receptors, Estrogen/metabolism , Receptors, Estrogen/antagonists & inhibitors , Intestinal Mucosa/metabolism , Intestinal Mucosa/drug effects , Intestinal Mucosa/pathology , Interleukin-6/metabolism , Tumor Necrosis Factor-alpha/metabolism , Mice , Molecular Docking Simulation , Anti-Inflammatory Agents/pharmacology , Anti-Inflammatory Agents/therapeutic use , Anti-Inflammatory Agents/chemistry , Anti-Inflammatory Agents/chemical synthesis , Pyridines/pharmacology , Pyridines/chemical synthesis , Pyridines/chemistry , Pyridines/therapeutic use , Mice, Inbred C57BL , Structure-Activity RelationshipABSTRACT
Prions are infectious protein particles known to cause prion diseases. The biochemical entity of the pathogen is the misfolded prion protein (PrPSc) that forms insoluble amyloids to impair brain function. PrPSc interacts with the non-pathogenic, cellular prion protein (PrPC) and facilitates conversion into a nascent misfolded isoform. Several small molecules have been reported to inhibit the aggregation of PrPSc but no pharmacological intervention was well established thus far. We, here, report that acylthiosemicarbazides inhibit the prion aggregation. Compounds 7x and 7y showed almost perfect inhibition (EC50 = 5 µM) in prion aggregation formation assay. The activity was further confirmed by atomic force microscopy, semi-denaturing detergent agarose gel electrophoresis and real-time quaking induced conversion assay (EC50 = 0.9 and 2.8 µM, respectively). These compounds also disaggregated pre-existing aggregates in vitro and one of them decreased the level of PrPSc in cultured cells with permanent prion infection, suggesting their potential as a treatment platform. In conclusion, hydroxy-2-naphthoylthiosemicarbazides can be an excellent scaffold for the discovery of anti-prion therapeutics.