Druggable Sterol Metabolizing Enzymes in Infectious Diseases: Cell Targets to Therapeutic Leads.

Sterol biosynthesis via the mevalonate-isoprenoid pathway produces ergosterol (24β-methyl cholesta-5,7-dienol) necessary for growth in a wide-range of eukaryotic pathogenic organisms in eukaryotes, including the fungi, trypanosomes and amoebae, while their animal hosts synthesize a structurally less complicated product-cholesterol (cholest-5-enol). Because phyla-specific differences in sterol metabolizing enzyme architecture governs the binding and reaction properties of substrates and inhibitors while the order of sterol metabolizing enzymes involved in steroidogenesis determine the positioning of crucial chokepoint enzymes in the biosynthetic pathway, the selectivity and effectiveness of rationally designed ergosterol biosynthesis inhibitors toward ergosterol-dependent infectious diseases varies greatly. Recent research has revealed an evolving toolbox of mechanistically distinct tight-binding inhibitors against two crucial methylation-demethylation biocatalysts-the C24 sterol methyl transferase (absent from humans) and the C14-sterol demethylase (present generally in humans and their eukaryotic pathogens).

Unearthing the Janus-face cholesterogenesis pathways in cancer.

Cholesterol biosynthesis, primarily associated with eukaryotes, occurs as an essential component of human metabolism with biosynthetic deregulation a factor in cancer viability. The segment that partitions between squalene and the C-end cholesterol yields the main cholesterogenesis branch subdivided into the Bloch and Kandutsch-Russell pathways. Their importance in cell viability, in normal growth and development originates primarily from the amphipathic property and shape of the cholesterol molecule which makes it suitable as a membrane insert.

HBO1 is required for the maintenance of leukaemia stem cells.

Acute myeloid leukaemia (AML) is a heterogeneous disease characterized by transcriptional dysregulation that results in a block in differentiation and increased malignant self-renewal. Various epigenetic therapies aimed at reversing these hallmarks of AML have progressed into clinical trials, but most show only modest efficacy owing to an inability to effectively eradicate leukaemia stem cells (LSCs). Here, to specifically identify novel dependencies in LSCs, we screened a bespoke library of small hairpin RNAs that target chromatin regulators in a unique ex vivo mouse model of LSCs.

A nematode sterol C4α-methyltransferase catalyzes a new methylation reaction responsible for sterol diversity.

Primitive sterol evolution plays an important role in fossil record interpretation and offers potential therapeutic avenues for human disease resulting from nematode infections. Recognizing that C4-methyl stenol products [8(14)-lophenol] can be synthesized in bacteria while C4-methyl stanol products (dinosterol) can be synthesized in dinoflagellates and preserved as sterane biomarkers in ancient sedimentary rock is key to eukaryotic sterol evolution. In this regard, nematodes have been proposed to convert dietary cholesterol to 8(14)-lophenol by a secondary metabolism pathway that could involve sterol C4 methylation analogous to the C2 methylation of hopanoids (radicle-type mechanism) or C24 methylation of sterols (carbocation-type mechanism).

Discovery of Benzoylsulfonohydrazides as Potent Inhibitors of the Histone Acetyltransferase KAT6A.

A high-throughput screen for inhibitors of the histone acetyltransferase, KAT6A, led to identification of an aryl sulfonohydrazide derivative (CTX-0124143) that inhibited KAT6A with an IC of 1.0 μM. Elaboration of the structure-activity relationship and medicinal chemistry optimization led to the discovery of WM-8014 (), a highly potent inhibitor of KAT6A (IC = 0.

The influence of residential and workday population mobility on exposure to air pollution in the UK.

Traditional approaches of quantifying population-level exposure to air pollution assume that concentrations of air pollutants at the residential address of the study population are representative for overall exposure. This introduces potential bias in the quantification of human health effects. Our study combines new UK Census data comprising information on workday population densities, with high spatio-temporal resolution air pollution concentration fields from the WRF-EMEP4UK atmospheric chemistry transport model, to derive more realistic estimates of population exposure to NO, PM and O.

Inhibitors of histone acetyltransferases KAT6A/B induce senescence and arrest tumour growth.

Acetylation of histones by lysine acetyltransferases (KATs) is essential for chromatin organization and function. Among the genes coding for the MYST family of KATs (KAT5-KAT8) are the oncogenes KAT6A (also known as MOZ) and KAT6B (also known as MORF and QKF). KAT6A has essential roles in normal haematopoietic stem cells and is the target of recurrent chromosomal translocations, causing acute myeloid leukaemia.

Synthesis and Biological Activity of Sterol 14α-Demethylase and Sterol C24-Methyltransferase Inhibitors.

Sterol 14α-demethylase (SDM) is essential for sterol biosynthesis and is the primary molecular target for clinical and agricultural antifungals. SDM has been demonstrated to be a valid drug target for antiprotozoal therapies, and much research has been focused on using SDM inhibitors to treat neglected tropical diseases such as human African trypanosomiasis (HAT), Chagas disease, and leishmaniasis. Sterol C24-methyltransferase (24-SMT) introduces the C24-methyl group of ergosterol and is an enzyme found in pathogenic fungi and protozoa but is absent from animals.

Identification of natural RORγ ligands that regulate the development of lymphoid cells.

Mice deficient in the nuclear hormone receptor RORγt have defective development of thymocytes, lymphoid organs, Th17 cells, and type 3 innate lymphoid cells. RORγt binds to oxysterols derived from cholesterol catabolism, but it is not clear whether these are its natural ligands. Here, we show that sterol lipids are necessary and sufficient to drive RORγt-dependent transcription.

Discovery of an ergosterol-signaling factor that regulates Trypanosoma brucei growth.

Ergosterol biosynthesis and homeostasis in the parasitic protozoan Trypanosoma brucei was analyzed by RNAi silencing and inhibition of sterol C24β-methyltransferase (TbSMT) and sterol 14α-demethylase [TbSDM (TbCYP51)] to explore the functions of sterols in T. brucei growth. Inhibition of the amount or activity of these enzymes depletes ergosterol from cells at <6 fg/cell for procyclic form (PCF) cells or <0.

Inertia in an ombrotrophic bog ecosystem in response to 9 years' realistic perturbation by wet deposition of nitrogen, separated by form.

Wet deposition of nitrogen (N) occurs in oxidized (nitrate) and reduced (ammonium) forms. Whether one form drives vegetation change more than the other is widely debated, as field evidence has been lacking. We are manipulating N form in wet deposition to an ombrotrophic bog, Whim (Scottish Borders), and here report nine years of results.

Synthesis of 1,2,3-triazole linked galactopyranosides and evaluation of cholera toxin inhibition.

We report the synthesis of a series of bivalent 1,2,3-triazole linked galactopyranosides as potential inhibitors of cholera toxin (CT). The inhibitory activity of the bivalent series was examined (ELISA) and the series showed low inhibitory activity (millimolar IC(50)s). Conversely, the monomeric galactotriazole analogues were strong inhibitors of cholera toxin (IC(50) = 71-75 μM).

An analysis of total gaseous mercury (TGM) concentrations across the UK from a rural sampling network.

Total gaseous mercury was collected at ten sites, which comprise part of the UK rural heavy metals monitoring network, between 2005 and 2008. Using the gold amalgam technique to capture total gaseous mercury, samples were analysed using a Tekran 2537A mercury vapour analyser. The data showed no upward or downward trend in atmospheric mercury concentrations over the period, with 4 year average concentrations between 1.

Survey research techniques.

This article is an introduction to the basics of survey research. It discusses the strengths and weaknesses of different types of surveys, explains basic statistical concepts and offers guidance in preparing a research article for publication.

Effect of antagonism of the parathyroid hormone (PTH)/PTH-related protein receptor on decidualization in rat uterus.

Parathyroid hormone-related protein (PTHrP) was detected at 32.8 +/- 3.9 pmol 1-1 in uterine luminal fluid from immature rats treated with oestradiol.

Effect of parathyroid hormone-related protein (PTHrP) on the contractility of the myometrium and localization of PTHrP in the uterus of pregnant rats.

The effect of parathyroid hormone-related protein (PTHrP) on the contractility of uterine segments taken from pregnant rats and the localization of PTHrP in the uterus during pregnancy were investigated. PTHrP(1-34) had a potent inhibitory effect on spontaneous contractions of the longitudinal layer of uterine myometrium taken from rats at day 4 of pregnancy (IC50 1.6 nmol l-1).

Effect of treatment of dairy cows with slow-release bovine somatotropin during the periparturient period on minerals in plasma and milk and on parathyroid hormone-related protein in milk.

Slow-release bST was given to dairy cows as a single injection prior to calving to determine whether such treatment prevented parturient hypocalcemia or modified the concentrations of Ca and parathyroid hormone-related protein in milk during the periparturient period. Cows were treated about 1 wk prepartum, and serial blood and milk samples were taken from these and similar prepartum control cows over a 3-wk period. Plasma growth hormone concentrations in the bST-treated group reached a peak 2 d after administration and then declined linearly to control concentrations over a 14-d period.

Foscarnet inhibits vascular smooth muscle contraction.

Foscarnet inhibited noradrenaline and calcium-mediated contractions of the isolated perfused tail artery of the rat. When the noradrenaline contractile response was split into two components, where the first was due to the release of calcium from intracellular stores and the second to the influx of calcium from the extracellular fluid, foscarnet (30 microM) inhibited only the first component of the response. Foscarnet did not inhibit the calcium influx component of the noradrenaline contraction, nor did it affect the inhibition of this component by the L-type calcium channel antagonists verapamil and nicardipine.

Production of parathyroid hormone-related protein by the rat mammary gland in pregnancy and lactation.

Production of parathyroid hormone-related protein by the rat mammary gland in pregnancy and lactation. Am. J.

Oestrogen enhancement of the myometrial response to exogenous parathyroid hormone-related protein (PTHrP), and tissue localization of endogenous PTHrP and its mRNA in the virgin rat uterus.

Classical pharmacological studies have shown that oestrogen dominance in humans and other animals can increase the responsiveness of the uterus to many locally acting peptides. Parathyroid hormone-related protein (PTHrP) has been shown to be expressed in the pregnant and non-pregnant rat uterus and exogenous PTHrP is known to relax uterine contraction in vitro. We investigated whether oestrogen dominance can influence the responsiveness of the uterine horn to PTHrP, and further studied the localization of PTHrP mRNA and protein in the rat uterine horn using in-situ hybridization and immunohistochemistry.

The interaction of phosphine with haemoglobin and erythrocytes.

1. Phosphine progressively converts oxyhaemoglobin to methaemoglobin and hemichrome species, with the product formed being time- and concentration-dependent. 2.

Functional and morphological changes induced by tunicamycin in dividing and confluent endothelial cells.

Cultured bovine aortic endothelial cells treated with tunicamycin, an inhibitor of glycoprotein synthesis, developed a concentration-dependent inhibition of N-acetylglucosamine-1-phosphate transferase activity, and this inhibition was correlated with a substantial decrease in [3H]mannose incorporation by the cells. Endothelial cells were very sensitive to tunicamycin, and changes in their morphology occurred as a result of the inhibition of glycoprotein synthesis. The cells became elongated, the surface irregular, roughened, and granular, and there was an increase in the interstitial space between the cells.

Clodronate inhibits contraction and prevents the action of L-type calcium channel antagonists in vascular smooth muscle.

Clodronate (dichloromethylenebisphosphonate) decreased vasoconstriction of the isolated perfused rat tail artery mediated by norepinephrine and by Ca2+ in a K(+)-depolarizing solution. The norepinephrine contractile response was divided into two components by sequential manipulation of the composition of the perfusion fluid, where the first component is due to the release of Ca2+ from intracellular stores and the second to the influx of Ca2+ from extracellular fluid. Clodronate (20 microM) decreased only the first component of the response at a norepinephrine concentration of 50 nM, and both components of the response at a higher norepinephrine concentration (100 nM).