3-(7-Azaindolyl)-4-arylmaleimides as potent, selective inhibitors of glycogen synthase kinase-3

A novel series of acyclic 3-(7-azaindolyl)-4-(aryl/heteroaryl)maleimides was synthesized and evaluated for activity against GSK-3beta and selectivity versus PKC-betaII, as well as a broad panel of protein kinases. Compounds 14 and 17c potently inhibited GSK-3beta (IC(50)=7 and 26 nM, respectively) and exhibited excellent selectivity over PKC-betaII (325 and >385-fold, respectively). Compound 17c was also highly selective against 68 other protein kinases. In a cell-based functional assay, both 14 and 17c effectively increased glycogen synthase activity by inhibiting GSK-3beta.     

Aza-bicyclic amino acid sulfonamides as alpha(4)beta(1)/alpha(4)beta(7) integrin antagonists

The design, synthesis, and biological activity of novel alpha(4)beta(1) and alpha(4)beta(7) integrin antagonists, containing a bridged azabicyclic nucleus, are reported. Conformational analysis of targets containing an azabicyclo[2.2.2]octane carboxylic acid and known integrin antagonists indicated that this azabicycle would be a suitable molecular scaffold. Variation of substituents on the pendant arylsulfonamide and phenylalanine groups resulted in potent alpha(4)beta(1)-selective and dual alpha(4)beta(1)/alpha(4)beta(7) antagonists. Potent compounds 11i, 11h, and 14 were effective in the antigen-sensitized sheep model of asthma.     

Molecular basis of bitter taste

The sense of taste responds to a large variety of stimuli through specific transduction mechanisms. The molecular events in the perception of bitter taste are believed to start with the binding of specific water-soluble molecules to G-protein-coupled receptors encoded by the type 2 family of taste receptor genes and expressed at the surface of taste receptor cells. Recent advances in the identification and cloning of the complete repertoire of genes of this family in humans and rodents provide an opportunity to address unresolved questions in bitter taste. The functional characterization of some of the receptors that these genes encode suggests that it will be possible to understand more precisely their specific functions.     

Marked inhibition of retinal neovascularization in rats following soluble-flt-1 gene transfer

BACKGROUND: In mouse models of retinopathy of prematurity (ROP) inhibitors of vascular endothelial growth factor (VEGF) functions administered systemically completely block retinal neovascularization. In contrast, selective ocular VEGF depletion has achieved an approx. 50% inhibition of retinal neovascular growth. It is unclear whether a more complete inhibition of new blood vessel development can be obtained with an anti-VEGF therapy localized to the eye. Therefore, the objective of the present study was to determine the effect of local anti-VEGF therapy in a different animal model which closely mimics human ROP. METHODS: Rats were exposed to alternating cycles of high and low levels of oxygen for 14 days immediately after birth; thereafter, they were intravitreally injected with an adenoviral vector expressing a secreted form of the VEGF receptor flt-1 (Ad.sflt), which acts by sequestering VEGF. Contralateral eyes were injected with the control vector carrying the reporter gene expressing beta-galactosidase (Ad.betaGal). RESULTS: At the peak of retinal neovascular growth, i.e. post-natal day 21 (P21), we observed up to 97.5% decrease in retinal neovascularization in animals injected with Ad.sflt. At the end of observation (P28), no significant difference in retinal vessel number was detected in both oxygen-injured and normoxic Ad.sflt-treated retinas compared with untreated or Ad.betaGal-treated retinas. CONCLUSION: Adenoviral-mediated sflt-1 gene transfer induces a near-complete inhibition of ischemia-induced retinal neovascularization in rats without affecting pre-existing retinal vessels.     

Inhibition of Candida albicans secreted aspartic protease by a novel series of peptidomimetics,also active on the HIV-1 protease

Nineteen reduced amide, monohydroxy- or dihydroxyethylene-based transition-state peptidomimetics, known to be good inhibitors of the aspartic protease of HIV-1, were tested against a secreted aspartic protease (Sap2), purified from the culture medium of a virulent strain of Candida albicans. Ten of these compounds exhibited IC(50)s against Sap2 lower than 15 microM; the best inhibitor, Kyn-Val-Phe-Psi[OH-OH]-Phe-Val-Kyn, when added to the C. albicans culture, repressed the hydrolysis of bovine serum albumin (BSA), contained in the culture medium, and inhibited the growth of the fungus.     

The interplay between folding-facilitating mechanisms in Trypanosoma cruzi endoplasmic reticulum

Lectin (calreticulin [CRT])-N-glycan-mediated quality control of glycoprotein folding is operative in trypanosomatid protozoa but protein-linked monoglucosylated N-glycans are exclusively formed in these microorganisms by UDP-Glc:glycoprotein glucosyltransferase (GT)-dependent glucosylation. The gene coding for this enzyme in the human pathogen Trypanosoma cruzi was identified and sequenced. Even though several of this parasite glycoproteins have been identified as essential components of differentiation and mammalian cell invasion processes, disruption of both GT-encoding alleles did not affect cell growth rate of epimastigote form parasites and only partially affected differentiation and mammalian cell invasion. The cellular content of one of the already identified T. cruzi glycoprotein virulence factors (cruzipain, a lysosomal proteinase) only showed a partial (5-20%) decrease in GT null mutants in spite of the fact that >90% of all cruzipain molecules interacted with CRT during their folding process in wild-type cells. Although extremely mild cell lysis and immunoprecipitation procedures were used, no CRT-cruzipain interaction was detected in GT null mutants but secretion of the proteinase was nevertheless delayed because of a lengthened interaction with Grp78/BiP probably caused by the detected induction of this chaperone in GT null mutants. This result provides a rationale for the absence of a more drastic consequence of GT absence. It was concluded that T. cruzi endoplasmic reticulum folding machinery presents an exquisite plasticity that allows the parasite to surmount the absence of the glycoprotein-specific folding facilitation mechanism.     

Interleukin secretion, proteoglycan and procollagen alpha(1)(I) gene expression in Crouzon fibroblasts treated with basic fibroblast growth factor

The present study provides the first evidence that fibroblasts obtained from patients affected by Crouzon syndrome, a rare craniosynostosis, despite mutations in the high-affinity bFGF receptor retain their capacity to respond to bFGF. The growth factor reduces IL-1 secretion, downregulates biglycan and procollagen alpha(1)(I), and increases betaglycan expression. Since betaglycan is a co-receptor for bFGF signalling, an alternative signal transduction pathway is suggested in Crouzon fibroblasts, to explain the documented changes in ECM macromolecule production.     

Backbone dynamics of human Cu,Zn superoxide dismutase and of its monomeric F50E/G51E/E133Q mutant: the influence of dimerization on mobility and function

The backbone assignment of reduced human dimeric Cu,Zn superoxide dismutase (SOD) was performed on a sample 100% enriched in (15)N, (13)C and 70% enriched in (2)H. (15)N T(1), T(2), and T(1)(rho) and (15)N-(1)H NOE assignment was performed at 600 MHz proton frequency on both wild-type SOD and the monomeric F50E/G51E/E133Q mutant. This allowed a comparison of the mobility in the subnanosecond and in the millisecond to microsecond time scales of the two systems. Both proteins are rather rigid, although some breathing of the beta sheets is detected in the wild type dimer. The monomer displays large mobility in the loops in the first part of the sequence, in loop IVa where point mutations have been introduced and at the C-terminus. The dimeric wild type is rigidified at loop IVa and at the C-terminus. Only loop VII shows a higher mobility in the dimer (besides some individual NH moieties). Conformational equilibria are displayed in the monomeric form around cysteines 57 and 146, thus explaining the disorder of arginine 143 which is the most important residue in guiding O(2)(-) toward the copper ion. The larger mobility in the wild type form with respect to the monomer in the picosecond to nanosecond time scale of helix alpha1 and loop VIIb, which provides the correct electrostatic driving force for O(2)(-) in the active channel, has been discussed in terms of favoring the activity of SOD.