Reverse cholesterol transport promoted by HDL-apoA-I is an important mechanism of protection against atherosclerosis. We have previously identified apoA-I mimetic peptides by synthesizing analogs of ...the 22 amino acid apoA-I consensus sequence (apoA-I
cons) containing non-natural aliphatic amino acids. Here we examined the effect of different aliphatic non-natural amino acids on the structure–activity relationship (SAR) of apoA-I mimetic peptides. These novel apoA-I mimetics, with long hydrocarbon chain (C
5–8) amino acids incorporated in the amphipathic α helix of the apoA-I
cons, have the following properties: (i) they stimulate in vitro cholesterol efflux from macrophages via ABCA1; (ii) they associate with HDL and cause formation of pre-β HDL particles when incubated with human and mouse plasma; (iii) they associate with HDL and induce pre-β HDL formation in vivo, with a corresponding increase in ABCA1-dependent cholesterol efflux capacity ex vivo; (iv) at high dose they associate with VLDL and induce hypertriglyceridemia in mice. These results suggest our peptide design confers activities that are potentially anti-atherogenic. However a dosing regimen which maximizes their therapeutic properties while minimizing adverse effects needs to be established.
Niacin is an effective drug for raising HDL cholesterol. However, niacin must be taken in large doses and significant side effects are often observed, including facial flushing, loss of glucose ...tolerance, and liver toxicity. An anthranilic acid was identified as an agonist of the niacin receptor. In order to improve efficacy and provide structural diversity, replacements for the anthranilic acid were investigated and several compounds with improved properties were identified.
High-density lipoprotein (HDL)-targeting therapies, including reconstituted HDL (rHDL), are attractive agents for treating dyslipidemia and atherosclerosis, as they may increase HDL levels and ...enhance therapeutic activities associated with HDL, including reverse cholesterol transport (RCT). Using CSL-111, a rHDL consisting of native human apolipoprotein AI (hApoAI) and phospholipids, we characterized the acute effects of rHDL administration in C57Bl/6 mice to (i) further our understanding of the mechanism of action of rHDL, and (ii) evaluate the usefulness of the mouse as a preclinical model for HDL-targeting therapies. After a single injection of CSL-111, there was a dose- and time-dependent increase of hApoAI, human pre-β HDL, total cholesterol, and triglycerides in serum, consistent with the effects of CSL-111 in humans. However, unlike in humans, there was no measurable increase in cholesteryl esters. Evaluated ex vivo, the ATP binding cassette A1 (ABCA1)- and scavenger receptor type BI (SR-BI)-dependent cholesterol efflux capacity of serum from CSL-111-treated mice was increased compared with serum from vehicle-treated animals. Fractionation by size exclusion chromatography of lipoproteins in serum from treated mice revealed hApoAI in particles the size of endogenous HDL and slightly larger, cholesterol-enriched particles of all sizes, including sizes distinct from endogenous HDL or CSL-111 itself, and triglyceride-enriched particles the size of very-low-density lipoprotein (VLDL). These results suggest that in mouse blood CSL-111 is remodeled and generates enhanced cholesterol efflux capacity which increases mobilization of free cholesterol from peripheral tissues. Our findings complement the previous reports on CSL-111 in human participants and provide data with which to evaluate the potential utility of mouse models in mechanistic studies of HDL-targeting therapies.
Novel 1-(2-aminopyrazin-3-yl)methyl-2-thioureas are described as inhibitors of MK-2. These compounds demonstrate potent in vitro activity against the enzyme with IC
50 values as low as 15
nM, and ...suppress expression of TNFα in THP-1 cells and in vivo in an acute inflammation model in mice.
Novel 1-(2-aminopyrazin-3-yl)methyl-2-thioureas are described as inhibitors of mitogen-activated protein kinase-activated protein kinase 2 (MK-2). These compounds demonstrate potent in vitro activity against the enzyme with IC
50 values as low as 15
nM, and suppress expression of TNFα in THP-1 cells and in vivo in an acute inflammation model in mice. The synthesis, structure–activity relationship (SAR), and biological evaluation of these compounds are discussed.
Altered lipoprotein metabolism in P2Y 13 knockout mice Blom, Daniël; Yamin, Ting-ting; Champy, Marie-France ...
Biochimica et biophysica acta. Molecular and cell biology of lipids,
2010, Letnik:
1801, Številka:
12
Journal Article
Recenzirano
The purinergic receptor P2Y
13 has been shown to play a role in the uptake of holo-HDL particles in
in vitro hepatocyte experiments. In order to determine the role of P2Y
13 in lipoprotein metabolism
...in vivo, we ablated the expression of this gene in mice. Here we show that P2Y
13 knockout mice have lower fecal concentrations of neutral sterols (−
27%
±
2.1% in males) as well as small decreases in plasma HDL (−
13.1%
±
3.2% in males; −
17.5%
±
4.0% in females) levels. In addition, significant decreases were detected in serum levels of fatty acids and glycerol in female P2Y
13 knockout mice. Hepatic mRNA profiling analyses showed increased expression of SREBP-regulated cholesterol and fatty acid biosynthesis genes, while fatty acid β-oxidation genes were significantly decreased. Liver gene signatures also identified changes in PPARα-regulated transcript levels. With the exception of a small increase in bone area, P2Y
13 knockout mice do not show any additional major abnormalities, and display normal body weight, fat mass and lean body mass. No changes in insulin sensitivity and oral glucose tolerance could be detected. Taken together, our experiments assess a role for the purinergic receptor P2Y
13 in the regulation of lipoprotein metabolism and demonstrate that modulating its activity could be of benefit to the treatment of dyslipidemia in people.
►P2Y13 knockout mice have lower fecal concentrations of neutral sterols. ►P2Y13 knockout mice have small decreases in plasma HDL levels. ►Female P2Y13 KO mice have lower plasma fatty acid and glycerol levels. ►P2Y13 KO have normal body weight, fat mass, insulin sensitivity and OGTT.
A series of betamethasone 17α-carbamates were designed, synthesized, and evaluated for their ability to dissociate the two main functions of the glucocorticoid receptor, that is, transactivation and ...transrepression, in rat cell lines. A number of alkyl substituted betamethasone 17α-carbamates were identified with excellent affinity for the glucocorticoid receptor (e.g.,
7, GR IC
50 5.1
nM) and indicated dissociated profiles in functional assays of transactivation (rat tyrosine aminotransferase, TAT, and rat glutamine synthetase, GS) and transrepression (human A549 cells, MMP-1 assay). Gratifyingly, the in-vivo profile of these compounds, for example,
7, also indicated potent anti-inflammatory activity with impaired effects on glucose, insulin, triglycerides, and body weight. Taken together, these results indicate that dissociated glucocorticoid receptor modulators can be identified in rodents.
Compound
15 displayed the profile of a dissociated glucocorticoid in vitro and reduced inflammation in a mouse.
A series of novel ligands for the glucocorticoid receptor containing two heterocycles ...were synthesized. These compounds were investigated for a dissociative profile using transrepression and transactivation assays. Several compounds were tested in vivo and showed the ability to reduce inflammation in a mouse.
The p38 MAP kinase signal transduction pathway is an important regulator of proinflammatory cytokine production and inflammation. Defining the roles of the various p38 family members, specifically ...p38alpha and p38beta, in these processes has been difficult. Here we use a chemical genetics approach using knock-in mice in which either p38alpha or p38beta kinase has been rendered resistant to the effects of specific inhibitors along with p38beta knock-out mice to dissect the biological function of these specific kinase isoforms. Mice harboring a T106M mutation in p38alpha are resistant to pharmacological inhibition of LPS-induced TNF production and collagen antibody-induced arthritis, indicating that p38beta activity is not required for acute or chronic inflammatory responses. LPS-induced TNF production, however, is still completely sensitive to p38 inhibitors in mice with a T106M point mutation in p38beta. Similarly, p38beta knock-out mice respond normally to inflammatory stimuli. These results demonstrate conclusively that specific inhibition of the p38alpha isoform is necessary and sufficient for anti-inflammatory efficacy in vivo.
The p38 MAP kinase signal transduction pathway is an important regulator of proinflammatory cytokine production and inflammation.
Defining the roles of the various p38 family members, specifically ...p38α and p38β, in these processes has been difficult. Here
we use a chemical genetics approach using knock-in mice in which either p38α or p38β kinase has been rendered resistant to
the effects of specific inhibitors along with p38β knock-out mice to dissect the biological function of these specific kinase
isoforms. Mice harboring a T106M mutation in p38α are resistant to pharmacological inhibition of LPS-induced TNF production
and collagen antibody-induced arthritis, indicating that p38β activity is not required for acute or chronic inflammatory responses.
LPS-induced TNF production, however, is still completely sensitive to p38 inhibitors in mice with a T106M point mutation in
p38β. Similarly, p38β knock-out mice respond normally to inflammatory stimuli. These results demonstrate conclusively that
specific inhibition of the p38α isoform is necessary and sufficient for anti-inflammatory efficacy in vivo .
The enzymes that catalyze the oxidative metabolism of arachidonic acid have provided fertile ground for the development of useful therapeutic agents for nearly a quarter century. Inhibitors of the ...enzyme cyclooxygenase prevent the formation of the prostaglandins and thromboxanes and are clinically useful antiinflammatories and peripheral analgesics. More recently it has been discovered that the enzyme 5-lipoxygenase is the first step in the formation of a series of biologically important metabolites of arachidonic acid, the leukotrienes. Evidence suggests that an inhibitor of 5-lipoxygenase may be a useful therapeutic agent in the treatment of asthma, immediate hypersensitivity, and inflammation. Various antioxidants have been examined as inhibitors of 5-lipoxygenase in vitro. We were intrigued by recent reports that the 2,3-dihydro-5-benzofuranol ring system maximizes the stereoelectronic effects necessary for efficient hydrogen atom abstraction by peroxyl radicals. In this study we describe the synthesis of over 50 new 2,3-dihydro-5-benzofuranols and their biological evaluation as inhibitors of leukotriene biosynthesis in isolated human polymorphonuclear leukocytes. We show that the 2,3-dihydro-5-benzofuranol ring system, although not a potent inhibitor of leukotriene biosynthesis in itself, can provide a useful template for the design of antioxidant-based inhibitors of leukotriene biosynthesis. Furthermore, within a structural class the potency of a given analogue can be predicted on the basis of its overall calculated lipophilicity (log P). The data are interpreted in terms of a model in which the observed inhibition by this class of inhibitors is dependent on the intrinsic ability of the antioxidant to reduce the enzyme and on the fraction of the inhibitor that is partitioned into the membrane.
PDF
