RESUMO
The complete biosynthetic pathways of the potent antifungals AS2077715 (1) and funiculosin (2) are reconstituted and characterized. A five-enzyme cascade, including a multifunctional flavin-dependent monooxygenease and a repurposed O-methyltransferase, is involved to perform the dearomatization, stereoselective ring contraction, and redox transformations to morph a hydroxyphenyl-containing precursor into the unusual all-cis cyclopentanetetraol moiety.
Assuntos
Antifúngicos , OxirreduçãoRESUMO
Val-boroPro (Talabostat, PT-100), a nonselective inhibitor of post-proline cleaving serine proteases, stimulates mammalian immune systems through an unknown mechanism of action. Despite this lack of mechanistic understanding, Val-boroPro has attracted substantial interest as a potential anticancer agent, reaching phase 3 trials in humans. Here we show that Val-boroPro stimulates the immune system by triggering a proinflammatory form of cell death in monocytes and macrophages known as pyroptosis. We demonstrate that the inhibition of two serine proteases, DPP8 and DPP9, activates the pro-protein form of caspase-1 independent of the inflammasome adaptor ASC. Activated pro-caspase-1 does not efficiently process itself or IL-1ß but does cleave and activate gasdermin D to induce pyroptosis. Mice lacking caspase-1 do not show immune stimulation after treatment with Val-boroPro. Our data identify what is to our knowledge the first small molecule that induces pyroptosis and reveals a new checkpoint that controls the activation of the innate immune system.
Assuntos
Ácidos Borônicos/farmacologia , Caspase 1/metabolismo , Dipeptidases/antagonistas & inibidores , Dipeptídeos/farmacologia , Dipeptidil Peptidases e Tripeptidil Peptidases/antagonistas & inibidores , Leucócitos Mononucleares/efeitos dos fármacos , Macrófagos/efeitos dos fármacos , Piroptose/efeitos dos fármacos , Inibidores de Serina Proteinase/farmacologia , Animais , Ácidos Borônicos/química , Caspase 1/deficiência , Linhagem Celular , Dipeptidases/metabolismo , Dipeptídeos/química , Dipeptidil Peptidases e Tripeptidil Peptidases/metabolismo , Relação Dose-Resposta a Droga , Humanos , Leucócitos Mononucleares/enzimologia , Leucócitos Mononucleares/patologia , Macrófagos/enzimologia , Macrófagos/patologia , Camundongos , Conformação Molecular , Inibidores de Serina Proteinase/química , Relação Estrutura-AtividadeRESUMO
4-Hydroxy-2-pyridone alkaloids have attracted attention for synthetic and biosynthetic studies due to their broad biological activities and structural diversity. Here, we elucidated the pathway and chemical logic of (-)-sambutoxin (1) biosynthesis. In particular, we uncovered the enzymatic origin of the tetrahydropyran moiety and showed that the p-hydroxyphenyl group is installed via a late-stage, P450-catalyzed oxidation of the phenylalanine-derived side chain rather than via a direct incorporation of tyrosine.