RESUMO
Utilizing a phenotypic screen, we identified chemical matter that increased astrocytic apoE secretion in vitro. We designed a clickable photoaffinity probe based on a pyrrolidine lead compound and carried out probe-based quantitative chemical proteomics in human astrocytoma CCF-STTG1 cells to identify liver x receptor ß (LXRß) as the target. Binding of the small molecule ligand stabilized LXRß, as shown by cellular thermal shift assay (CETSA). In addition, we identified a probe-modified peptide by mass spectrometry and proposed a model where the photoaffinity probe is bound in the ligand-binding pocket of LXRß. Taken together, our findings demonstrated that the lead chemical matter bound directly to LXRß, and our results highlight the power of chemical proteomic approaches to identify the target of a phenotypic screening hit. Additionally, the LXR photoaffinity probe and lead compound described herein may serve as valuable tools to further evaluate the LXR pathway.
Assuntos
Apolipoproteínas E/metabolismo , Astrócitos/metabolismo , Receptores X do Fígado/metabolismo , Astrócitos/citologia , Linhagem Celular , Humanos , Ligantes , Ligação Proteica , ProteômicaRESUMO
γ-Secretase, a four-subunit transmembrane aspartic proteinase, is a highly valued drug target in Alzheimer's disease and cancer. Despite significant progress in structural studies, the respective molecular mechanisms and binding modes of γ-secretase inhibitors (GSIs) and modulators (GSMs) remain uncertain. Here, we developed biotinylated cleavable-linker photoprobes based on the BMS-708163 GSI to study its interaction with γ-secretase. Comparison of four cleavable linkers indicated that the hydrazine-labile N-1-(4,4-dimethyl-2,6-dioxocyclohexylidene)ethyl (Dde) linker was cleaved most efficiently to release photolabeled and affinity-captured presenilin-1 (PS1), the catalytic subunit of γ-secretase. Peptide mapping showed that the BMS-708163-based probe photoinserted at L282 of PS1. This insertion site was consistent with the results of molecular dynamics simulations of the γ-secretase complex with inhibitor. Taken together, this work reveals the binding site of a GSI and offers insights into the mechanism of action of this class of inhibitors.
Assuntos
Secretases da Proteína Precursora do Amiloide/antagonistas & inibidores , Inibidores Enzimáticos/farmacologia , Sondas Moleculares/farmacologia , Oxidiazóis/farmacologia , Sulfonamidas/farmacologia , Secretases da Proteína Precursora do Amiloide/metabolismo , Sítios de Ligação/efeitos dos fármacos , Inibidores Enzimáticos/química , Humanos , Simulação de Dinâmica Molecular , Sondas Moleculares/síntese química , Sondas Moleculares/química , Estrutura Molecular , Oxidiazóis/química , Sulfonamidas/síntese química , Sulfonamidas/químicaRESUMO
INTRODUCTION: To determine whether single nucleotide polymorphisms (SNPs) in FAS and related genes are associated with acute kidney injury (AKI) in patients with acute respiratory distress syndrome (ARDS). METHODS: We studied 401 (Caucasian N = 310 and African-American N = 91) patients aged ≥ 13 years with ALI who enrolled in the Fluid and Catheter Treatment Trial (FACTT) between 2000 and 2005 from 20 North American centers. We genotyped 367 SNPs in 45 genes of the Fas/Fas ligand pathway to identify associations between SNPs in Fas pathway genes and the development of AKI by day 2 after enrollment in FACTT, adapting Acute Kidney Injury Network (AKIN) criteria. Written informed consent was obtained from participants or legally authorized surrogates in the original FACTT study and available to use for secondary analysis. RESULTS: In Caucasian patients, we identified associations between two SNPs and the incidence of AKI (stage 1 and above): rs1050851 and rs2233417; both are found within the gene for nuclear factor of kappa light polypeptide gene enhancer in B-cells inhibitor, alpha (NFKBIA). For rs1050851 and rs2233417, the odds ratios (ORs) were 2.34 (95 % confidence interval (CI) = 1.58-3.46, p = 1.06 × 10(-5), FDR = 0.003) and 2.46 (CI = 1.61-3.76, p = 1.81 × 10(-5), FDR = 0.003) for each minor allele, respectively. The associations were stronger still for AKIN stage 2-3 with respective ORs 4.00 (CI = 2.10-7.62, p = 1.05 × 10(-5), FDR = 0.003) and 4.03 (CI = 2.09-7.77, p = 1.88 × 10(-5), FDR = 0.003) for each minor allele homozygote. We observed no significant association between these SNPs and AKI in the smaller subset of African Americans. CONCLUSION: In Caucasian patients with ALI, the presence of minor alleles in two SNPs in NFKBIA was strongly associated with the development of AKI. TRIAL REGISTRATION: NCT00281268 . Registered 20/01/2006.
Assuntos
Injúria Renal Aguda/genética , Proteína Ligante Fas/genética , Polimorfismo de Nucleotídeo Único , Injúria Renal Aguda/etiologia , Negro ou Afro-Americano/genética , Alelos , Feminino , Estudos de Associação Genética , Predisposição Genética para Doença/genética , Humanos , Proteínas I-kappa B/genética , Masculino , Pessoa de Meia-Idade , Inibidor de NF-kappaB alfa , Polimorfismo de Nucleotídeo Único/genética , Síndrome do Desconforto Respiratório/complicações , Síndrome do Desconforto Respiratório/genética , Transdução de Sinais/genética , População Branca/genéticaRESUMO
Nitric oxide (NO) is an important signaling molecule in the human body, playing a crucial role in cell and neuronal communication, regulation of blood pressure, and in immune activation. However, overproduction of NO by the neuronal isoform of nitric oxide synthase (nNOS) is one of the fundamental causes underlying neurodegenerative disorders and neuropathic pain. Therefore, developing small molecules for selective inhibition of nNOS over related isoforms (eNOS and iNOS) is therapeutically desirable. The aims of this review focus on the regulation and dysregulation of NO signaling, the role of NO in neurodegeneration and pain, the structure and mechanism of nNOS, and the use of this information to design selective inhibitors of this enzyme. Structure-based drug design, the bioavailability and pharmacokinetics of these inhibitors, and extensive target validation through animal studies are addressed.