The discovery, synthesis and biological evaluation of a novel series of 7-isoxazoloquinolines is described. Several analogs are shown to increase ApoA1 expression within the nanomolar range in the ...human hepatic cell line HepG2.
Mapping quantitative trait loci (QTLs) with high resolution facilitates identification and positional cloning of the underlying genes. The novel approach of advanced intercross lines (AILs) generates ...many more recombination events and thus can potentially narrow QTLs significantly more than do conventional backcrosses and F2 intercrosses. In this study, we carried out QTL analyses in (C57BL/6J x NZB/BlNJ) x C57BL/6J backcross progeny fed either chow or an atherogenic diet to detect QTLs that regulate high-density lipoprotein cholesterol (HDL)concentrations, and in (C57BL/6J x NZB/BlNJ) F11 AIL progeny to confirm and narrow those QTLs. QTLs for HDL concentrations were found on chromosomes 1, 5, and 16. AIL not only narrowed the QTLs significantly more than did a conventional backcross but also resolved a chromosome 5 QTL identified in the backcross into two QTLs, the peaks of both being outside the backcross QTL region. We tested 27 candidate genes and found significant mRNA expression differences for 12 (Nr1i3, Apoa2, Sap, Tgfb2, Fgfbp1, Prom, Ppargc1, Tcf1, Ncor2, Srb1, App, and Ifnar). Some of these underlay the same QTL, indicating that expression differences are common and not sufficient to identify QTL genes. All the major HDL QTLs in our study had homologous counterparts in humans, implying that their underlying genes regulate HDL in humans.
Interaction of pathogens with cells of the immune system results in activation of inflammatory gene expression. This response, although vital for immune defence, is frequently deleterious to the host ...due to the exaggerated production of inflammatory proteins. The scope of inflammatory responses reflects the activation state of signalling proteins upstream of inflammatory genes as well as signal-induced assembly of nuclear chromatin complexes that support mRNA expression. Recognition of post-translationally modified histones by nuclear proteins that initiate mRNA transcription and support mRNA elongation is a critical step in the regulation of gene expression. Here we present a novel pharmacological approach that targets inflammatory gene expression by interfering with the recognition of acetylated histones by the bromodomain and extra terminal domain (BET) family of proteins. We describe a synthetic compound (I-BET) that by 'mimicking' acetylated histones disrupts chromatin complexes responsible for the expression of key inflammatory genes in activated macrophages, and confers protection against lipopolysaccharide-induced endotoxic shock and bacteria-induced sepsis. Our findings suggest that synthetic compounds specifically targeting proteins that recognize post-translationally modified histones can serve as a new generation of immunomodulatory drugs.
Celotno besedilo
Dostopno za:
DOBA, IJS, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
A novel series of quinoline isoxazole BET family bromodomain inhibitors are discussed. Crystallography is used to illustrate binding modes and rationalize their SAR. One member, I-BET151 ...(GSK1210151A), shows good oral bioavailability in both the rat and minipig as well as demonstrating efficient suppression of bacterial induced inflammation and sepsis in a murine in vivo endotoxaemia model.
Natriuretic peptide receptors have been found in different heart preparations. However, the role of natriuretic peptides in the regulation of cardiac contractility remains largely elusive and was, ...therefore, studied here.
The rate of relaxation of electrically stimulated, isolated rat papillary muscles was enhanced (114.4±1.4%, P<0.01) after addition of C‐type natriuretic peptide (CNP; 1 μM). Time to peak tension decreased in parallel (88±3 and 75±2 msec before and 5 min after addition of CNP, respectively, P<0.01). On the other hand, the rate of contraction slowly decreased when CNP was added to the papillary muscles. These results show that CNP displays a positive lusitropic effect associated with a negative inotropic effect. The effects of CNP were mimicked by 8‐bromo‐guanosine 3′,5′ cyclic monophosphate.
Addition of CNP to isolated adult rat cardiomyocytes, induced a 25 fold increase in guanosine 3′,5′ cyclic monophosphate (cGMP) levels and stimulated the phosphorylation of phospholamban and troponin I, two proteins involved in the regulation of cardiac contractility. The levels of adenosine 3′,5′ cyclic monophosphate (cAMP) were not affected by the addition of CNP to the myocytes. The CNP‐dependent phospholamban phosphorylation was accompanied by the activation of the sarcoplasmic reticulum Ca2+‐ATPase.
In summary, CNP exerts a positive lusitropic effect, in rat papillary muscles. The putative mechanism involved in the lusitropism induced by this peptide, a cGMP‐dependent enhancement of the rate of relaxation with a slowly developing negative inotropic effect, seems different to that described for catecholamines.
British Journal of Pharmacology (1999) 128, 206–212; doi:10.1038/sj.bjp.0702766
Epigenetic mechanisms of gene regulation have a profound role in normal development and disease processes. An integral part of this mechanism occurs through lysine acetylation of histone tails which ...are recognized by bromodomains. While the biological and structural characterization of many bromodomain containing proteins has advanced considerably, the therapeutic tractability of this protein family is only now becoming understood. This paper describes the discovery and molecular characterization of potent (nM) small molecule inhibitors that disrupt the function of the BET family of bromodomains (Brd2, Brd3, and Brd4). By using a combination of phenotypic screening, chemoproteomics, and biophysical studies, we have discovered that the protein–protein interactions between bromodomains and acetylated histones can be antagonized by selective small molecules that bind at the acetylated lysine recognition pocket. X-ray crystal structures of compounds bound into bromodomains of Brd2 and Brd4 elucidate the molecular interactions of binding and explain the precisely defined stereochemistry required for activity.
Modification of the hydantoin ring in the previously described lead compound 2a has led to the discovery of compound 12a, tadalafil, a highly potent and highly selective PDE5 inhibitor. The ...replacement of the hydantoin in compound 2a by a piperazinedione ring led to compound cis- 11a which showed similar PDE5 inhibitory potency. Introduction of a 3,4-methylenedioxy substitution on the phenyl ring in position 6 led to a potent PDE5 inhibitor cis- 11c with increased cellular potency. Optimization of the chain on the piperazinedione ring led to the identification of the racemic cis- N-methyl derivative 11i. High diastereospecificity for PDE5 inhibition was observed in the piperazinedione series with the cis-(6R,12aR) enantiomer displaying the highest PDE5 inhibitory activity. The piperazinedione 12a, tadalafil (GF196960), has been identified as a highly potent PDE5 inhibitor (IC50 = 5 nM) with high selectivity for PDE5 vs PDE1−4 and PDE6. Compound 12a displays 85-fold greater selectivity vs PDE6 than sildenafil 1. 12a showed profound and long-lasting blood pressure lowering activity (30 mmHg/>7 h) in the spontaneously hypertensive rat model after oral administration (5 mg/kg).
Starting from ethyl β-carboline-3-carboxylate (β-CCE), 1, a modest inhibitor of type 5 phosphodiesterase (PDE5), a series of functionalized tetrahydro-β-carboline derivatives has been identified as a ...novel chemical class of potent and selective PDE5 inhibitors. Optimization of the side chain on the hydantoin ring of initial lead compound 2 and of the aromatic ring on position 5 led to the identification of compound 6e, a highly potent and selective PDE5 inhibitor, with greater selectivity for PDE5 vs PDE1−4 than sildenafil. Compound 6e demonstrated a long-lasting and significant blood pressure lowering effect after iv administration in the spontaneously hypertensive rat model but showed only moderate oral in vivo efficacy.
Staurosporine is the most potent inhibitor of protein kinase C (PKC) described in the literature with a half-maximal inhibitory
concentration (IC50) of 10 nM. Nevertheless, this natural product is ...poorly selective when assayed against other protein kinases.
In order to obtain specific PKC inhibitors, a series of bisindolylmaleimides has been synthesized. Structure-activity relationship
studies allowed the determination of the substructure responsible for conferring high potency and lack of selectivity in the
staurosporine molecule. Several aminoalkyl bisindolylmaleimides were found to be potent and selective PKC inhibitors (IC50
values from 5 to 70 nM). Among these compounds GF 109203X has been chosen for further studies aiming at the characterization
of this chemical family. GF 109203X was a competitive inhibitor with respect to ATP (Ki = 14 +/- 3 NM) and displayed high
selectivity for PKC as compared to five different protein kinases. We further determined the potency and specificity of GF
109203X in two cellular models: human platelets and Swiss 3T3 fibroblasts. GF 109203X efficiently prevented PKC-mediated phosphorylations
of an Mr = 47,000 protein in platelets and of an Mr = 80,000 protein in Swiss 3T3 cells. In contrast, in the same models,
the PKC inhibitor failed to prevent PKC-independent phosphorylations. GF 109203X inhibited collagen- and alpha-thrombin-induced
platelet aggregation as well as collagen-triggered ATP secretion. However, ADP-dependent reversible aggregation was not modified.
In Swiss 3T3 fibroblasts, GF 109203X reversed the inhibition of epidermal growth factor binding induced by phorbol 12,13-dibutyrate
and prevented 3H thymidine incorporation into DNA, only when this was elicited by growth promoting agents which activate
PKC. Our results illustrate the potential of GF 109203X as a tool for studying the involvement of PKC in signal transduction
pathways.
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