A series of 5-(5,6)-dihydrouracil substituted 8-hydroxy-[1,6]naphthyridine-7-carboxylic acid 4-fluorobenzylamide inhibitors of HIV-1 integrase and viral replication in cells

Introduction of a 5,6-dihydrouracil functionality in the 5-position of N-(4-fluorobenzyl)-8-hydroxy-[1,6]naphthyridine-7-carboxamide 1 led to a series of highly active HIV-1 integrase inhibitors. These compounds displayed low nanomolar activity in inhibiting both the strand transfer process of HIV-1 integrase and viral replication in cells. Compound 11 is a 150-fold more potent antiviral agent than 1, with a CIC(95) of 40 nM in the presence of human serum. It displays good pharmacokinetics when dosed in rats and dogs.     

Substance P stimulates cyclooxygenase-2 and prostaglandin E2 expression through JAK-STAT activation in human colonic epithelial cells

Substance P (SP) via its neurokinin-1 receptor (NK-1R) regulates several gastrointestinal functions. We previously reported that NK-1R-mediated chloride secretion in the colon involves formation of PG. PGE2 biosynthesis is controlled by cyclooxygenase-1 (COX-1) and COX-2, whose induction involves the STATs. In this study, we examined whether SP stimulates PGE2 production and COX-2 expression in human nontransformed NCM460 colonocytes stably transfected with the human NK-1R (NCM460-NK-1R cells) and identified the pathways involved in this response. SP exposure time and dose dependently induced an early (1-min) phosphorylation of JAK2, STAT3, and STAT5, followed by COX-2 expression and PGE2 production by 2 h. Pharmacologic experiments showed that PGE2 production is dependent on newly synthesized COX-2, but COX-1 protein. Inhibition of protein kinase Ctheta (PKCtheta), but not PKCepsilon and PKCdelta, significantly reduced SP-induced COX-2 up-regulation, and JAK2, STAT3, and STAT5 phosphorylation. Pharmacological blockade of JAK inhibited SP-induced JAK2, STAT3, and STAT5 phosphorylation; COX-2 expression; and PGE2 production. Transient transfection with JAK2 short-interferring RNA reduced COX-2 promoter activity and JAK2 phosphorylation, while RNA interference of STAT isoforms showed that STAT5 predominantly mediates SP-induced COX-2 promoter activity. Site-directed mutation of STAT binding sites on the COX-2 promoter completely abolished COX-2 promoter activity. Lastly, COX-2 expression was elevated in colon of mice during experimental colitis, and this effect was normalized by administration of the NK-1R antagonist CJ-12,255. Our results demonstrate that SP stimulates COX-2 expression and PGE2 production in human colonocytes via activation of the JAK2-STAT3/5 pathway.     

Termination and activation of store‐operated cyclic AMP production

Diverse pathophysiological processes (e.g. obesity, lifespan determination, addiction and male fertility) have been linked to the expression of specific isoforms of the adenylyl cyclases (AC1‐AC10), the enzymes that generate cyclic AMP (cAMP). Our laboratory recently discovered a new mode of cAMP production, prominent in certain cell types, that is stimulated by any manoeuvre causing reduction of free [Ca²⁺] within the lumen of the endoplasmic reticulum (ER) calcium store. Activation of this ‘store‐operated’ pathway requires the ER Ca²⁺ sensor, STIM1, but the identity of the enzymes responsible for cAMP production and how this process is regulated is unknown. Here, we used sensitive FRET‐based sensors for cAMP in single cells combined with silencing and overexpression approaches to show that store‐operated cAMP production occurred preferentially via the isoform AC3 in NCM460 colonic epithelial cells. Ca²⁺ entry via the plasma membrane Ca²⁺ channel, Orai1, suppressed cAMP production, independent of store refilling. These findings are an important first step towards defining the functional significance and to identify the protein composition of this novel Ca²⁺/cAMP crosstalk system.     

Release of the cytokines colony-stimulating factor-1, granulocyte-macrophage colony-stimulating factor, and IL-6 by cloned murine vascular smooth muscle cells

Vascular smooth muscle cells were cultured from the mesenteric arteries of MRL lpr/lpr, MRL +/+, CBA/J, or C3H/HeJ mice and evaluated for their ability to synthesize a range of cytokines. Vascular smooth muscle cells of MRL +/+, MRL lpr/lpr, and CBA/J origin released biologically significant amounts of CSF-1 and IL-6 and relatively low but detectable amounts of granulocyte macrophage-CSF (GM-CSF) but not IL-2, IL-3, or IL-4. Vascular smooth muscle cells of C3H/HeJ origin produced lower amounts of CSF-1 and IL-6, and GM-CSF was barely detectable. Production of these cytokines did not require the exogenous growth factors present in FCS and occurred, although at lower levels, in serum-free medium supplemented with insulin, transferrin, and albumin. Cloned lines of MRL +/+ vascular smooth muscle cells, with electron microscopic and immunochemical properties of vascular smooth muscle cells, produced CSF-1, IL-6, and GM-CSF, establishing that vascular smooth muscle cells were a direct source of CSF-1, IL-6, and GM-CSF. These observations highlight the need for experiments to directly address the question of whether vascular smooth muscle cells constitutively produce these cytokines under physiologic conditions in vivo and suggest that vascular smooth muscle cells may participate actively in inflammation by releasing cytokines that are active on lympho-hemopoietic and other cells.     

Comparison of the biochemical and kinetic properties of the type 1 receptor tyrosine kinase intracellular domains. Demonstration of differential sensitivity to kinase inhibitors.

Epidermal growth factor receptor (EGFR), ErbB-2, and ErbB-4 are members of the type 1 receptor tyrosine kinase family. Overexpression of these receptors, especially ErbB-2 and EGFR, has been implicated in multiple forms of cancer. Inhibitors of EGFR tyrosine kinase activity are being evaluated clinically for cancer therapy. The potency and selectivity of these inhibitors may affect the efficacy and toxicity of therapy. Here we describe the expression, purification, and biochemical comparison of EGFR, ErbB-2, and ErbB-4 intracellular domains. Despite their high degree of sequence homology, the three enzymes have significantly different catalytic properties and substrate kinetics. For example, the catalytic activity of ErbB-2 is less stable than that of EGFR. ErbB-2 uses ATP-Mg as a substrate inefficiently compared with EGFR and ErbB-4. The three enzymes have very similar substrate preferences for three optimized peptide substrates, but differences in substrate synergies were observed. We have used the biochemical and kinetic parameters determined from these studies to develop an assay system that accurately measures inhibitor potency and selectivity between the type 1 receptor family. We report that the selectivity profile of molecules in the 4-anilinoquinazoline series can be modified through specific aniline substitutions. Moreover, these compounds have activity in whole cells that reflect the potency and selectivity of target inhibition determined with this assay system.     

Messenger RNA species synthesized in vitro by the virion-associated RNA polymerase of vesicular stomatitis virus.

The virion-associated RNA-dependent RNA polymerase of vesicular stomatitis virus (VSV) synthesizes in vitro two size classes of RNA products similar to those observed in VSV-infected cells. One RNA product sediments at 31S with an approximate molecular weight of 2.1 X 106. The smaller products consist of at least three classes of RNA sedimenting at 17S, 14.5S, and 12S with molecular weights of 0.7 X 106, 0.52 X 106, and 0.37 X 106, respectively. Hybridization experiments show that both the 31S and 12-18S RNA products are complementary to the genome RNA, and that each class is transcribed from different nucleotide sequences. From the molecular weights of the RNA species and the hybridization experiments, it seems that almost the entire VSV genome RNA is transcribed in vitro.     

Corollin,coronillin and coronarian: Three new 3-nitropropanoyl-d-glucopyranoses from Coronilla varia

Three new 3-nitropropanoyl-d-glucopyranoses, 2,3,6-tri(3-nitropropanoyl)-α-d-glucopyranose (corollin), 1,2,6-tri(3-nitropropanoyl)-α-d-glucopyranose (coronillin) and 2,6-di(3-nitropropanoyl)-α-d-glucopyranose (coronarian) were isolated from the aerial parts of Coronilla varia. Structural assignments were made on the basis of 220 MHz NMR spectra.