Design, synthesis and preclinical evaluation of bio-conjugated amylinomimetic peptides as long-acting amylin receptor agonists.

Pramlintide is an equipotent amylin analogue that reduces food intake and body weight in obese subjects and has been clinically approved as an adjunctive therapy for the treatment of adult diabetic patients. However, due to its extremely short half-life in vivo, a regimen of multiple daily administrations is required for achieving clinical effectiveness. Herein is described the development of prototypical long-acting pramlintide bioconjugates, in which pramlintide's disulfide-linked macrocycle was replaced by a cyclic thioether motif. This modification enabled stable chemical conjugation to a half-life extending antibody. In contrast to pramlintide (t1/2 < 0.75 h), bioconjugates 35 and 38 have terminal half-lives of ∼2 days in mice and attain significant exposure levels that are maintained up to 7 days. Single dose subcutaneous administration of 35 in lean mice, given 18-20 h prior to oral acetaminophen (AAP) administration, significantly reduced gastric emptying (as determined by plasma AAP levels). In a separate study, similar administration of 35 in fasted lean mice effected a reduction in food intake for up to 48 h. These data are consistent with durable amylinomimetic responses and provide the basis for further development of such long-acting amylinomimetic conjugates for the potential treatment of obesity and associated pathologies.

Integrated expressional analysis: application to the drug discovery process.

Microarray technology enables high-throughput testing of gene expression to investigate various neuroscience related questions. This in turn creates a demand for scalable methods to confirm microarray results and the opportunity to use this information to discover and test novel pathways and therapeutic applications. Discovery of new central nervous system (CNS) treatments requires a comprehensive understanding of multiple aspects including the biology of a target, the pathophysiology of a disease/disorder, and the selection of successful lead compounds as well as efficient biomarker and drug disposition strategies such as absorption (how a drug is absorbed), distribution (how a drug spreads through an organism), metabolism (chemical conversion of a drug, if any, and into which substances), and elimination (how is a drug eliminated) (ADME). Understanding of the toxicity is also of paramount importance. These approaches, in turn, require novel high-content integrative assay technologies that provide thorough information about changes in cell biology. To increase efficiency of profiling, characterization, and validation, we established a new screening strategy that combines high-content image-based testing on Array Scan (Cellomics) with a confocal system and the multiplexed TaqMan RT-PCR method for quantitative mRNA expression analysis. This approach could serve as an interface between high-throughput microarray testing and specific application of markers discovered in the course of a microarray experiment. Markers could pinpoint activation or inhibition of a molecular pathway related, for instance, to neuronal viability. We demonstrate the successful testing of the same cell population in an image-based translocational assay followed by poly(A) mRNA capture and multiplexed single tube RT-PCR. In addition, Ciphergen ProteinChip analysis can be performed on the supernatant, thus allowing significant complementarity in the data output and interpretation by also including the capture and initial analysis of proteins in the integrative approach presented. We have determined various conditions including the number of cells, RT and PCR optimization, which are necessary for successful detection and consequent assay integration. We also show the successful convergence of various different approaches and multiplexing of different targets within a single real-time PCR tube. This novel integrative technological approach has utility for CNS drug discovery, target and biomarker identification, selection and characterization as well as for the study of toxicity- and adverse event-associated molecular mechanisms.

A novel, potent dual inhibitor of the leukocyte proteases cathepsin G and chymase: molecular mechanisms and anti-inflammatory activity in vivo.

Certain leukocytes release serine proteases that sustain inflammatory processes and cause disease conditions, such as asthma and chronic obstructive pulmonary disease. We identified beta-ketophosphonate 1 (JNJ-10311795; RWJ-355871) as a novel, potent dual inhibitor of neutrophil cathepsin G (K(i) = 38 nm) and mast cell chymase (K(i) = 2.3 nm). The x-ray crystal structures of 1 complexed with human cathepsin G (1.85 A) and human chymase (1.90 A) reveal the molecular basis of the dual inhibition. Ligand 1 occupies the S(1) and S(2) subsites of cathepsin G and chymase similarly, with the 2-naphthyl in S(1), the 1-naphthyl in S(2), and the phosphonate group in a complex network of hydrogen bonds. Surprisingly, however, the carboxamido-N-(naphthalene-2-carboxyl)piperidine group is found to bind in two distinct conformations. In cathepsin G, this group occupies the hydrophobic S(3)/S(4) subsites, whereas in chymase, it does not; rather, it folds onto the 1-naphthyl group of the inhibitor itself. Compound 1 exhibited noteworthy anti-inflammatory activity in rats for glycogen-induced peritonitis and lipopolysaccharide-induced airway inflammation. In addition to a marked reduction in neutrophil influx, 1 reversed increases in inflammatory mediators interleukin-1alpha, interleukin-1beta, tissue necrosis factor-alpha, and monocyte chemotactic protein-1 in the glycogen model and reversed increases in airway nitric oxide levels in the lipopolysaccharide model. These findings demonstrate that it is possible to inhibit both cathepsin G and chymase with a single molecule and suggest an exciting opportunity in the treatment of asthma and chronic obstructive pulmonary disease.

Novel indolylindazolylmaleimides as inhibitors of protein kinase C-beta: synthesis, biological activity, and cardiovascular safety.

Novel indolylindazolylmaleimides were synthesized and examined for kinase inhibition. We identified low-nanomolar inhibitors of PKC-beta with good to excellent selectivity vs other PKC isozymes and GSK-3beta. In a cell-based functional assay, 8f and 8i effectively blocked IL-8 release induced by PKC-betaII (IC(50) = 20-25 nM). In cardiovascular safety assessment, representative lead compounds bound to the hERG channel with high affinity, potently inhibited ion current in a patch-clamp experiment, and caused a dose-dependent increase of QT(c) in guinea pigs.

Macrocyclic bisindolylmaleimides as inhibitors of protein kinase C and glycogen synthase kinase-3.

Efficient methods were developed to synthesize a novel series of macrocyclic bisindolylmaleimides containing linkers with multiple heteroatoms. Potent inhibitors (single digit nanomolar IC(50)) for PKC-beta and GSK-3beta were identified, and compounds showed good selectivity over PKC-alpha, -gamma, -delta, -epsilon, and -zeta. Representative compound 5a also had high selectivity in a screening panel of 10 other protein kinases. In cell-based functional assays, several compounds effectively blocked interleukin-8 release induced by PKC-betaII and increased glycogen synthase activity by inhibiting GSK-3beta.