RESUMO
Stimulator of interferon genes (STING) is a dimeric transmembrane adapter protein that plays a key role in the human innate immune response to infection and has been therapeutically exploited for its antitumor activity. The activation of STING requires its high-order oligomerization, which could be induced by binding of the endogenous ligand, cGAMP, to the cytosolic ligand-binding domain. Here we report the discovery through functional screens of a class of compounds, named NVS-STGs, that activate human STING. Our cryo-EM structures show that NVS-STG2 induces the high-order oligomerization of human STING by binding to a pocket between the transmembrane domains of the neighboring STING dimers, effectively acting as a molecular glue. Our functional assays showed that NVS-STG2 could elicit potent STING-mediated immune responses in cells and antitumor activities in animal models.
Assuntos
Proteínas Adaptadoras de Transdução de Sinal , Proteínas de Membrana , Animais , Humanos , Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Bioensaio , Citosol , Imunidade Inata , Ligantes , Proteínas de Membrana/metabolismoRESUMO
The incidence of dengue fever epidemics has increased dramatically over the last few decades. However, no vaccine or antiviral therapies are available. Therefore, the need for safe and effective antiviral drugs has become imperative. The entry of dengue virus into a host cell is mediated by its major envelope (E) protein. The crystal structure of the E protein reveals a hydrophobic pocket that is presumably important for low-pH-mediated membrane fusion. High-throughput docking with this hydrophobic pocket was performed, and hits were evaluated in cell-based assays. Compound 6 was identified as one of the inhibitors and had an average 50% effective concentration of 119 nM against dengue virus serotype 2 in a human cell line. Mechanism-of-action studies demonstrated that compound 6 acts at an early stage during dengue virus infection. It arrests dengue virus in vesicles that colocalize with endocytosed dextran and inhibits NS3 expression. The inhibitors described in this report can serve as molecular probes for the study of the entry of flavivirus into host cells.
Assuntos
Antivirais/farmacologia , Vírus da Dengue/patogenicidade , Bibliotecas de Moléculas Pequenas , Internalização do Vírus/efeitos dos fármacos , Animais , Antivirais/química , Sítios de Ligação , Linhagem Celular , Cricetinae , Vírus da Dengue/efeitos dos fármacos , Vírus da Dengue/crescimento & desenvolvimento , Humanos , Modelos Moleculares , Relação Estrutura-Atividade , Proteínas do Envelope Viral/antagonistas & inibidoresRESUMO
Substrate-based tetrapeptide inhibitors with various warheads were designed, synthesized, and evaluated against the Dengue virus NS3 protease. Effective inhibition was achieved by peptide inhibitors with electrophilic warheads such as aldehyde, trifluoromethyl ketone, and boronic acid. A boronic acid has the highest affinity, exhibiting a K(i) of 43 nM.
Assuntos
Química Farmacêutica/métodos , Vírus da Dengue/enzimologia , Desenho de Fármacos , Peptídeos/farmacologia , Inibidores de Proteases/química , Proteínas não Estruturais Virais/antagonistas & inibidores , Proteínas não Estruturais Virais/química , Ácidos Borônicos/química , Relação Dose-Resposta a Droga , Inibidores Enzimáticos/farmacologia , Cetonas/química , Cinética , Modelos Químicos , Peptídeos/química , Inibidores de Proteases/farmacologia , RNA Helicases/antagonistas & inibidores , RNA Helicases/química , Serina Endopeptidases/química , Especificidade por Substrato , Fatores de TempoRESUMO
With the aim of discovering potent and selective dengue NS3 protease inhibitors, we systematically synthesized and evaluated a series of tetrapeptide aldehydes based on lead aldehyde 1 (Bz-Nle-Lys-Arg-Arg-H, K(i)=5.8 microM). In general, we observe that interactions of P(2) side chain are more important than P(1) followed by P(3) and P(4). Tripeptide and dipeptide aldehyde inhibitors also show low micromolar activity. Additionally, an effective non-basic, uncharged replacement of P(1) Arg is identified.