Primary human mDC1, mDC2, and pDC dendritic cells are differentially infected and activated by respiratory syncytial virus

Respiratory syncytial virus (RSV) causes recurrent infections throughout life. Vaccine development may depend upon understanding the molecular basis for induction of ineffective immunity. Because dendritic cells (DCs) are critically involved in early responses to infection, their interaction with RSV may determine the immunological outcome of RSV infection. Therefore, we investigated the ability of RSV to infect and activate primary mDCs and pDCs using recombinant RSV expressing green fluorescent protein (GFP). At a multiplicity of infection of 5, initial studies demonstrated ～6.8% of mDC1 and ～0.9% pDCs were infected. We extended these studies to include CD1c(-)CD141(+) mDC2, finding mDC2 infected at similar frequencies as mDC1. Both infected and uninfected cells upregulated phenotypic markers of maturation. Divalent cations were required for infection and maturation, but maturation did not require viral replication. There is evidence that attachment and entry/replication processes exert distinct effects on DC activation. Cell-specific patterns of RSV-induced maturation and cytokine production were detected in mDC1, mDC2, and pDC. We also demonstrate for the first time that RSV induces significant TIMP-2 production in all DC subsets. Defining the influence of RSV on the function of selected DC subsets may improve the likelihood of achieving protective vaccine-induced immunity.     

Discovery of a potent and selective 5-ht5A receptor antagonist by high-throughput chemistry

High-throughput screening of an array of biphenylmethylamines synthesised by high-throughput solid-phase chemistry resulted in the identification of compounds with high-affinity for the 5-ht5A receptor. The structure-activity relationship within this series and further array synthesis led to the identification of the biphenylmethylamine derivative 11, a potent and selective 5-ht5A receptor antagonist.     

Synthetic modification of the 2-oxypropionic acid moiety in 2-{4-[(7-chloro-2-quinoxalinyl)oxy]phenoxy}propionic acid (XK469), and consequent antitumor effects. Part 4

The criteria for the activity of 2-{4-[(7-chloro-2-quinoxalinyl)oxy]phenoxy}propionic acid (XK469) and 2-{4-[(7-bromo-2-quinolinyl)oxy]phenoxy}propionic acid (SH80) against transplanted tumors in mice established in previous studies, require a (7-halo-2-quinoxalinoxy)- or a (7-halo-2-quinolinoxyl)-residue, respectively, bridged via a 1,4-OC(6)H(4)O-linker to C(2) of propionic acid. The present work demonstrates that substitution of fluorine at the 3-position of the 1,4-OC(6)H(4)O-linker of XK469 leads to a 10-fold reduction in activity, whereas the corresponding 2-fluoro analog proved to be 100-fold less active than XK469. Moreover, the latter tolerated substitution of but a single, additional methyl group to the 2-position of the propionic acid moiety, that is, the isobutyric acid analog, without loss of significant in vivo activity. Indeed, an intact 2-oxypropionic acid moiety is a prerequisite for maximum antitumor activity of 1a.     

A yeast model system for functional analysis of the Niemann-Pick type C protein 1 homolog, Ncr1p

Niemann-Pick disease type C (NP-C) is a progressive, ultimately fatal, autosomal recessive neurodegenerative disorder. The major biochemical hallmark of the disease is the endocytic accumulation of low-density lipoprotein-derived cholesterol. The majority of NP-C patients have mutations in the Niemann-Pick type C1 gene, NPC1. This study focuses on the Saccharomyces cerevisiae homolog of the human NPC1 protein encoded by the NCR1 gene. Ncr1p localizes to the vacuole, the yeast equivalent to the mammalian endosome-lysosome system. Here, we identify the first phenotype caused by deletion of NCR1 from the yeast genome, resistance to the ether lipid drug, edelfosine. Our results indicate that edelfosine has a cytotoxic, rather than cytostatic, effect on wildtype yeast cells. We exploit the edelfosine resistance phenotype to assess the function of yeast Ncr1 proteins carrying amino acid changes corresponding to human NPC1 patient mutations. We find that one of these amino acid changes severely compromises Ncr1p function as assessed using the edelfosine resistance assay. These findings establish S. cerevisiae as a model system that can be exploited to analyze the molecular consequences of patient mutations in NPC1 and provide the basis for future genetic studies using yeast.