RESUMO
The immunoproteasome subunit LMP7 (ß5i)/LMP2 (ß1i) dual blockade has been reported to suppress B cell differentiation and activation, suggesting that the dual inhibition of LMP7/LMP2 is a promising approach for treating autoimmune diseases. In contrast, the inhibition of the constitutive proteasome subunit ß5c correlates with cytotoxicity against non-immune cells. Therefore, LMP7/LMP2 dual inhibitors with high selectivity over ß5c may be desirable for treating autoimmune diseases. In this study, we present the optimization and discovery of α-amido boronic acids using cryo-electron microscopy (cryo-EM). The exploitation of structural differences between the proteasome subunits led to the identification of a highly selective LMP7/LMP2 dual inhibitor 19. Molecular dynamics simulation based on cryo-EM structures of the proteasome subunits complexed with 19 explained the inhibitory activity profile. In mice immunized with 4-hydroxy-3-nitrophenylacetyl conjugated to ovalbumin, results indicate that 19 is orally bioavailable and shows promise as potential treatment for autoimmune diseases.
Assuntos
Ácidos Borônicos , Microscopia Crioeletrônica , Complexo de Endopeptidases do Proteassoma , Inibidores de Proteassoma , Complexo de Endopeptidases do Proteassoma/metabolismo , Complexo de Endopeptidases do Proteassoma/química , Animais , Inibidores de Proteassoma/farmacologia , Inibidores de Proteassoma/química , Inibidores de Proteassoma/síntese química , Camundongos , Ácidos Borônicos/química , Ácidos Borônicos/farmacologia , Ácidos Borônicos/síntese química , Humanos , Relação Estrutura-Atividade , Cisteína Endopeptidases/metabolismo , Estrutura Molecular , Simulação de Dinâmica Molecular , Descoberta de DrogasRESUMO
Non-alcoholic steatohepatitis (NASH) is a fast-growing liver disease in the Western world. Currently, only a few animal models show both the metabolic and histological features of human NASH. We aimed to explore murine NASH models in a time dependent manner that exhibit metabolic, histological and transcriptomic hallmarks of human NASH. For this, the murine strains C57BL/6J, ob/ob, and KK-Ay were used and three types of nutritional regimes were administered: normal chow diet (NCD); high-fat, high-fructose, and high-cholesterol diet (fast food diet; FFD); or choline-deficient, L-amino acid-defined, high-fat diet (CDAHFD), for 2, 4, 8, 12, 18, 24, and 30â weeks. All strains under the FFD and CDAHFD regimes developed steatohepatitis. Among the strains treated with FFD, the non-alcoholic fatty liver disease (NAFLD) activity score, fibrosis progression and metabolic abnormalities such as hyperinsulinemia and obesity were more pronounced in ob/ob mice than in C57BL/6J and KK-Ay mice. In ob/ob mice fed FFD, the development of hepatic crown-like structures was confirmed. Furthermore, molecular pathways involved in steatohepatitis and fibrosis showed significant changes from as early as 2â weeks of starting the FFD regime. Ob/ob mice fed FFD showed metabolic, histological, and transcriptomic dysfunctions similar to human NASH, suggesting their potential as an experimental model to discover novel drugs for NASH.