RESUMO
Synthesis of doubly 3-O-coumarylmethyl-substituted thiodigalactosides from bis-3-O-propargyl-thiodigalactoside resulted in highly selective and high affinity galectin-3 inhibitors. Mutant studies, structural analysis, and molecular modeling revealed that the coumaryl substituents stack onto arginine side chains. One inhibitor displayed efficacy in a murine model of bleomycin-induced lung fibrosis similar to that of a known nonselective galectin-1/galectin-3 inhibitor, which strongly suggests that blocking galectin-3 glycan recognition is an important antifibrotic drug target.
Assuntos
Cumarínicos/química , Galactosídeos/química , Galectina 3/antagonistas & inibidores , Polissacarídeos/metabolismo , Fibrose Pulmonar/metabolismo , Tiogalactosídeos/química , Animais , Bleomicina , Cumarínicos/síntese química , Cumarínicos/farmacologia , Galactosídeos/síntese química , Galactosídeos/farmacologia , Galectina 3/genética , Galectina 3/metabolismo , Humanos , Camundongos , Modelos Moleculares , Mutação , Ligação Proteica , Fibrose Pulmonar/induzido quimicamente , Fibrose Pulmonar/patologia , Relação Estrutura-Atividade , Tiogalactosídeos/síntese química , Tiogalactosídeos/farmacologiaRESUMO
Discovery of glycan-competitive galectin-3-binding compounds that attenuate lung fibrosis in a murine model and that block intracellular galectin-3 accumulation at damaged vesicles, hence revealing galectin-3-glycan interactions involved in fibrosis progression and in intracellular galectin-3 activities, is reported. 3,3'-Bis-(4-aryltriazol-1-yl)thiodigalactosides were synthesized and evaluated as antagonists of galectin-1, -2, -3, and -4 N-terminal, -4 C-terminal, -7 and -8 N-terminal, -9 N-terminal, and -9 C-terminal domains. Compounds displaying low-nanomolar affinities for galectins-1 and -3 were identified in a competitive fluorescence anisotropy assay. X-ray structural analysis of selected compounds in complex with galectin-3, together with galectin-3 mutant binding experiments, revealed that both the aryltriazolyl moieties and fluoro substituents on the compounds are involved in key interactions responsible for exceptional affinities towards galectin-3. The most potent galectin-3 antagonist was demonstrated to act in an assay monitoring galectin-3 accumulation upon amitriptyline-induced vesicle damage, visualizing a biochemically/medically relevant intracellular lectin-carbohydrate binding event and that it can be blocked by a small molecule. The same antagonist administered intratracheally attenuated bleomycin-induced pulmonary fibrosis in a mouse model with a dose/response profile comparing favorably with that of oral administration of the marketed antifibrotic compound pirfenidone.
