Big flies, small repeats: the "Thr-Gly" region of the period gene in Diptera

The region of the clock gene period (per) that encodes a repetitive tract of threonine-glycine (Thr-Gly) pairs has been compared between Dipteran species both within and outside the Drosophilidae. All the non- Drosophilidae sequences in this region are short and present a remarkably stable picture compared to the Drosophilidae, in which the region is much larger and extremely variable, both in size and composition. The accelerated evolution in the repetitive region of the Drosophilidae appears to be mainly due to an expansion of two ancestral repeats, one encoding a Thr-Gly dipeptide and the other a pentapeptide rich in serine, glycine, and asparagine or threonine. In some drosophilids the expansion involves a duplication of the pentapeptide sequence, but in Drosophila pseudoobscura both the dipeptide and the pentapeptide repeats are present in larger numbers. In the nondrosophilids, however, the pentapeptide sequence is represented by one copy and the dipeptide by two copies. These observations fulfill some of the predictions of recent theoretical models that have simulated the evolution of repetitive sequences.      

Cloning and characterization of ADAMTS11, an aggrecanase from the ADAMTS family.

Aggrecan is responsible for the mechanical properties of cartilage. One of the earliest changes observed in arthritis is the depletion of cartilage aggrecan due to increased proteolytic cleavage within the interglobular domain. Two major sites of cleavage have been identified in this region at Asn(341)-Phe(342) and Glu(373)-Ala(374). While several matrix metalloproteinases have been shown to cleave at Asn(341)-Phe(342), an as yet unidentified protein termed "aggrecanase" is responsible for cleavage at Glu(373)-Ala(374) and is hypothesized to play a pivotal role in cartilage damage. We have identified and cloned a novel disintegrin metalloproteinase with thrombospondin motifs that possesses aggrecanase activity, ADAMTS11 (aggrecanase-2), which has extensive homology to ADAMTS4 (aggrecanase-1) and the inflammation-associated gene ADAMTS1. ADAMTS11 possesses a number of conserved domains that have been shown to play a role in integrin binding, cell-cell interactions, and extracellular matrix binding. We have expressed recombinant human ADAMTS11 in insect cells and shown that it cleaves aggrecan at the Glu(373)-Ala(374) site, with the cleavage pattern and inhibitor profile being indistinguishable from that observed with native aggrecanase. A comparison of the structure and expression patterns of ADAMTS11, ADAMTS4, and ADAMTS1 is also described. Our findings will facilitate the study of the mechanisms of cartilage degradation and provide targets to search for effective inhibitors of cartilage depletion in arthritic disease.     

Discovery of N-propylurea 3-benzylpiperidines as selective CC chemokine receptor-3 (CCR3) antagonists

The discovery of novel and selective small molecule antagonists of the CC Chemokine Receptor-3 (CCR3) is presented. Simple conversion from a 4- to 3-benzylpiperidine gave improved selectivity for CCR3 over the serotonin 5HT(2A) receptor. Chiral resolution and exploration of mono- and disubstitution of the N-propylurea resulted in several 3-benzylpiperidine N-propylureas with CCR3 binding IC(50)s under 5 nM. Data from in vitro calcium mobilization and chemotaxis assays for these compounds ranged from high picomolar to low nanomolar EC(50)s and correlated well with antagonist binding IC(50)s.     

CCR3 antagonists: a potential new therapy for the treatment of asthma. Discovery and structure-activity relationships

CCR3 antagonist leads with IC(50) values in the microM range were converted into low nM binding compounds that displayed in vitro inhibition of human eosinophil chemotaxis induced by human eotaxin. In particular, 4-benzylpiperidin-1-yl-n-propylureas and erythro-3-(4-benzyl-2-(alpha-hydroxyalkyl)piperidin-1-yl)-n-propylureas (obtained via Beak reaction of N-BOC-4-benzylpiperidine) exhibited single digit nanomolar IC(50) values for CCR3.     

Rational design, synthesis and structure-activity relationships of a cyclic succinate series of TNF-alpha converting enzyme inhibitors. Part 2: lead optimization

Modifications of the lead TACE inhibitor 1 (N-hydroxy-trans-2-[[4-(4-quinolinyloxymethyl)anilinyl]carbonyl]-1-cyclohexanecarboxamide) at the cyclohexyl ring and the quinoline moiety led to the identification of a series of piperidine containing TACE inhibitors with potent activity in the inhibition of TNF-alpha release in the whole blood assay (WBA). The most potent analogue IM491 [N-hydroxy-(5S,6S)-1-methyl-6-[[4-(2-methyl-4-quinolinylmethoxy)anilinyl]carbonyl]-5-piperidinecarboxamide] exhibited an IC(50) value of 20 nM in WBA with excellent selectivity over MMP-1, -2 and -9 and is orally bioavailable with an F value of 43% in beagle dogs.     

Alpha-ketoamides, alpha-ketoesters and alpha-diketones as HCV NS3 protease inhibitors

Peptide-based alpha-ketoamides, alpha-ketoesters and alpha-diketones were designed, synthesized and evaluated against HCV NS3 protease. Alpha-ketoamides have the highest affinity among the three classes, with 8 being the most potent inhibitor with an IC50 of 340 nM.     

Capped diaminopropionamide-glycine dipeptides are inhibitors of CC chemokine receptor 2 (CCR2)

A new series of CCR2 antagonists has been discovered that incorporates intramolecular hydrogen bonding as a strategy for rigidifying the scaffold. The structure-activity relationship was established through initial systematic modification of substitution pattern and chain length, followed by independent optimization of three different substituents (benzylamine, carboxamide, and benzamide). Several of the acyclic compounds display 10-30 nM binding affinity for CCR2. Moreover, these antagonists are able to block both MCP-1-induced Ca(2+) flux and monocyte chemotaxis, and are selective for binding to CCR2 over CCR1 and CCR3.