ABSTRACT
Structure-activity relationship studies on a series of Boc-indole derivatives as LXR agonists are described. Compound 1 was identified as an LXR agonist through structure-based virtual screening followed by high-throughput gene profiling. Replacement of the indan linker portion in 1 with an open-chain linker resulted in compounds with similar or improved in vitro potency and cellular functional activity. The Boc group at the N-1 position of the indole moiety can be replaced with a benzoyl group. The SAR studies led to the identification of compound 8, a potent LXRbeta agonist with an EC50 of 12 nM in the cofactor recruitment assay.
Subject(s)
DNA-Binding Proteins/agonists , Indoles/chemistry , Indoles/pharmacology , Receptors, Cytoplasmic and Nuclear/agonists , Binding Sites , Cell Line , Hepatocytes/drug effects , Hepatocytes/metabolism , Humans , Liver X Receptors , Models, Molecular , Molecular Structure , Orphan Nuclear Receptors , Sterol Regulatory Element Binding Protein 1/genetics , Sterol Regulatory Element Binding Protein 1/metabolism , Structure-Activity Relationship , Up-RegulationABSTRACT
A structurally novel liver X receptor (LXR) agonist (1) was identified from internal compound collection utilizing the combination of structure-based virtual screening and high-throughput gene profiling. Compound 1 increased ABCA1 gene expression by eightfold and SREBP1c by threefold in differentiated THP-1 macrophage cell lines. Confirmation of its agonistic activity against LXR was obtained in the co-factor recruitment and reporter transactivation assays. Structure-activity relationship studies on compound 1 are described.
Subject(s)
DNA-Binding Proteins/agonists , Gene Expression Regulation/drug effects , Indoles/pharmacology , Macrophages/drug effects , Monocytes/drug effects , Receptors, Cytoplasmic and Nuclear/agonists , ATP Binding Cassette Transporter 1 , ATP-Binding Cassette Transporters/genetics , ATP-Binding Cassette Transporters/metabolism , Cell Line , Gene Expression Regulation/physiology , Humans , Indoles/chemical synthesis , Liver X Receptors , Macrophages/metabolism , Models, Chemical , Monocytes/cytology , Orphan Nuclear Receptors , Sterol Regulatory Element Binding Protein 1/genetics , Sterol Regulatory Element Binding Protein 1/metabolism , Structure-Activity RelationshipABSTRACT
Bacillus thuringiensis crystal proteins of the Cry34 and Cry35 classes function as binary toxins showing activity on the western corn rootworm, Diabrotica virgifera virgifera LeConte. We surveyed 6,499 B. thuringiensis isolates by hybridization for sequences related to cry35A genes, identifying 78 strains. Proteins of the appropriate molecular mass (ca. 44 kDa) for Cry35 were observed in 42 of the strains. Full-length, or nearly full-length, sequences of 34 cry34 genes and 16 cry35 genes were also obtained from cloning, PCR analysis, and DNA sequencing. These included representatives of all known Cry34A, Cry34B, Cry35A, and Cry35B classes, as well as a novel Cry34A/Cry35A-like pair. Bioassay analysis indicated that cry35-hybridizing strains not producing a ca. 14-kDa protein, indicative of Cry34, were not active on corn rootworms, and that the previously identified Cry34A/Cry35A pairs were more active than the Cry34B/Cry35B pairs. The cry35-hybridizing B. thuringiensis strains were found in locales and materials typical for other B. thuringiensis strains. Comparison of the sequences with the geographic origins of the strains showed that identical, or nearly identical, sequences were found in strains from both Australasia and the Americas. Sequence similarity searches revealed that Cry34 proteins are similar to predicted proteins in Photorhabdus luminescens and Dictyostelium discoidium, and that Cry35Ab1 contains a segment similar to beta-trefoil domains that may be a binding motif. The binary Cry34/Cry35 B. thuringiensis crystal proteins thus appear closely related to each other, are environmentally ubiquitous, and share sequence similarities consistent with activity through membrane disruption in target organisms.
