gw-3965 and Atherosclerosis

The Liver X Receptors (LXRs) are oxysterol-activated transcription factors that upregulate a suite of genes that together promote coordinated mobilization of excess cholesterol from cells and from the body. The LXRs, like other nuclear receptors, are anti-inflammatory, inhibiting signal-dependent induction of pro-inflammatory genes by nuclear factor-κB, activating protein-1, and other transcription factors. Synthetic LXR agonists have been shown to ameliorate atherosclerosis and a wide range of inflammatory disorders in preclinical animal models. Although this has suggested potential for application to human disease, systemic LXR activation is complicated by hepatic steatosis and hypertriglyceridemia, consequences of lipogenic gene induction in the liver by LXRα. The past several years have seen the development of multiple advanced LXR therapeutics aiming to avoid hepatic lipogenesis, including LXRβ-selective agonists, tissue-selective agonists, and transrepression-selective agonists. Although several synthetic LXR agonists have made it to phase I clinical trials, none have progressed due to unforeseen adverse reactions or undisclosed reasons. Nonetheless, several sophisticated pharmacologic strategies, including structure-guided drug design, cell-specific drug targeting, as well as non-systemic drug routes have been initiated and remain to be comprehensively explored. In addition, recent studies have identified potential utility for targeting the LXRs during therapy with other agents, such as glucocorticoids and rexinoids. Despite the pitfalls encountered to date in translation of LXR agonists to human disease, it appears likely that this accelerating field will ultimately yield effective and safe applications for LXR targeting in humans.

Topics: Animals; Atherosclerosis; Benzoates; Benzylamines; Gene Expression Regulation; Humans; Hydrocarbons, Fluorinated; Inflammation; Liver X Receptors; Models, Biological; Molecular Targeted Therapy; Sulfonamides

Several new drug targets of anti-atherosclerosis, emerging in the recent years, such as PPAR agonists, cholesteryl ester transfer protein (CETP) inhibitors, infusion of apolipoprotein A-I (apoA-I), liver X receptor (LXR) activators and phospholipid transfer protein (PLTP) inhibitors etc were reviewed.

Topics: Apolipoprotein A-I; Atherosclerosis; Benzoates; Benzylamines; Cholesterol Ester Transfer Proteins; DNA-Binding Proteins; Humans; Liver X Receptors; Molecular Structure; Orphan Nuclear Receptors; Oxazines; Peroxisome Proliferator-Activated Receptors; Phenylpropionates; Quinolines; Receptors, Cytoplasmic and Nuclear

Endothelial progenitor cells (EPCs) promote the maintenance of the endothelium by secreting vasoreparative factors. A population of EPCs known as early outgrowth cells (EOCs) is being investigated as novel cell-based therapies for the treatment of cardiovascular disease. We previously demonstrated that the absence of liver X receptors (LXRs) is detrimental to the formation and function of EOCs under hypercholesterolemic conditions. Here, we investigate whether LXR activation in EOCs is beneficial for the treatment of atherosclerosis. EOCs were differentiated from the bone marrow of wild-type (WT) and LXR-knockout (Lxrαβ-/-) mice in the presence of vehicle or LXR agonist (GW3965). WT EOCs treated with GW3965 throughout differentiation showed reduced mRNA expression of endothelial lineage markers (Cd144, Vegfr2) compared with WT vehicle and Lxrαβ-/- EOCs. GW3965-treated EOCs produced secreted factors that reduced monocyte adhesion to activated endothelial cells in culture. When injected into atherosclerosis-prone Ldlr-/- mice, GW3965-treated EOCs, or their corresponding conditioned media (CM) were both able to reduce aortic sinus plaque burden compared with controls. Furthermore, when human EOCs (obtained from patients with established CAD) were treated with GW3965 and the CM applied to endothelial cells, monocyte adhesion was decreased, indicating that our results in mice could be translated to patients. Ex vivo LXR agonist treatment of EOCs therefore produces a secretome that decreases early atherosclerosis in Ldlr-/- mice, and additionally, CM from human EOCs significantly inhibits monocyte to endothelial adhesion. Thus, active factor(s) within the GW3965-treated EOC secretome may have the potential to be useful for the treatment of atherosclerosis.

Topics: Animals; Atherosclerosis; Benzoates; Benzylamines; Culture Media, Conditioned; Endothelial Progenitor Cells; Humans; Liver X Receptors; Mice; Mice, Knockout; Secretome

Liver X Receptor (LXR) is a potential drug target for atherosclerosis. One of the major challenges in taking LXR modulators to the clinic is steatosis. It was reported that sterol LXR agonists selectively activate LXR in the intestine and macrophage cells rather than in the liver. We hypothesize that sterol LXR agonists may selectively inhibit atherosclerosis without causing hepatic lipogenesis. Thus, based on LXR structure, 12 sterol compounds were designed and tested in a dual-luciferase reporter gene experiment. It was confirmed that compounds 4 and 6 were LXR agonists. Further experiments demonstrated that compounds 4 and 6 inhibit the formation of macrophage foam cells without inducing triglyceride accumulation in either hepatocytes or adipocytes. In vivo studies demonstrated that compound 4 promotes reverse cholesterol transport without inducing hepatic lipogenesis. Thus, we report that these compounds with sterol scaffolds can be promising leads for the treatment of atherosclerosis without inducing steatosis.

Topics: 3T3-L1 Cells; Animals; Atherosclerosis; Cell Differentiation; Dose-Response Relationship, Drug; Drug Discovery; HEK293 Cells; Hep G2 Cells; Hepatocytes; Humans; Lipogenesis; Liver X Receptors; Male; Mice; Mice, Inbred C57BL; Models, Molecular; Molecular Structure; RAW 264.7 Cells; Sterols; Structure-Activity Relationship

The rising prevalence of cardiovascular disease worldwide necessitates novel therapeutic approaches to manage atherosclerosis. Intravenously administered nanostructures are a promising noninvasive approach to deliver therapeutics that reduce plaque burden. The drug liver X receptor agonist GW3965 (LXR) can reduce atherosclerosis by promoting cholesterol efflux from plaque but causes liver toxicity when administered systemically at effective doses, thus preventing its clinical use. The ability of peptide amphiphile nanofibers containing apolipoprotein A1-derived targeting peptide 4F to serve as nanocarriers for LXR delivery (ApoA1-LXR PA) in vivo is investigated here. These nanostructures are found to successfully target atherosclerotic lesions in a mouse model within 24 h of injection. After 8 weeks of intravenous administration, the nanostructures significantly reduce plaque burden in both male and female mice to a similar extent as LXR alone in comparison to saline-treated controls. Furthermore, they do not cause increased liver toxicity in comparison to LXR treatments, which may be related to more controlled release by the nanostructure. These findings demonstrate the potential of supramolecular nanostructures as safe, effective drug nanocarriers to manage atherosclerosis.

Topics: Animals; Apolipoprotein A-I; Atherosclerosis; Benzoates; Benzylamines; Disease Models, Animal; Humans; Liver X Receptors; Mice; Molecular Targeted Therapy; Nanofibers; Nanostructures; Peptides; Surface-Active Agents

The signals that determine atherosclerosis-specific DNA methylation profiles are only partially known. We previously identified a 29-bp DNA motif (differential methylation motif [DMM]) proximal to CpG islands (CGIs) that undergo demethylation in advanced human atheromas. Those data hinted that the DMM docks modifiers of DNA methylation and transcription.. We sought to functionally characterize the DMM. We showed that the DMM overlaps with the RNA polymerase III-binding B box of. Collectively, the data suggest that a DMM is associated with 2 distinct methylation states: relatively low methylation of

Topics: Alu Elements; Atherosclerosis; Benzoates; Benzylamines; Binding Sites; CpG Islands; DNA Methylation; Epigenesis, Genetic; Gene Expression Profiling; Humans; Liver X Receptors; Nucleotide Motifs; Protein Binding; RNA, Long Noncoding; THP-1 Cells; Two-Hybrid System Techniques

The pharmacological manipulation of liver X receptors (LXRs) has been an attractive therapeutic strategy for atherosclerosis treatment as they control reverse cholesterol transport and inflammatory response. This study presents the development and efficacy of nanoparticles (NPs) incorporating the synthetic LXR agonist GW3965 (GW) in targeting atherosclerotic lesions. Collagen IV (Col IV) targeting ligands are employed to functionalize the NPs to improve targeting to the atherosclerotic plaque, and formulation parameters such as the length of the polyethylene glycol (PEG) coating molecules are systematically optimized. In vitro studies indicate that the GW-encapsulated NPs upregulate the LXR target genes and downregulate proinflammatory mediator in macrophages. The Col IV-targeted NPs encapsulating GW (Col IV-GW-NPs) successfully reaches atherosclerotic lesions when administered for 5 weeks to mice with preexisting lesions, substantially reducing macrophage content (≈30%) compared to the PBS group, which is with greater efficacy versus nontargeting NPs encapsulating GW (GW-NPs) (≈18%). In addition, mice administered the Col IV-GW-NPs do not demonstrate increased hepatic lipid biosynthesis or hyperlipidemia during the treatment period, unlike mice injected with the free GW. These findings suggest a new form of LXR-based therapeutics capable of enhanced delivery of the LXR agonist to atherosclerotic lesions without altering hepatic lipid metabolism.

Topics: Animals; Atherosclerosis; Benzoates; Benzylamines; Cells, Cultured; Cholesterol; Collagen Type IV; Disease Models, Animal; Drug Carriers; Lipid Metabolism; Liver; Liver X Receptors; Macrophages; Mice; Mice, Inbred C57BL; Mice, Knockout; Nanomedicine; Nanoparticles; Polyethylene Glycols; Receptors, LDL; Triglycerides

Immunological complexity in atherosclerosis warrants targeted treatment of specific inflammatory cells that aggravate the disease. With the initiation of large phase III trials investigating immunomodulatory drugs for atherosclerosis, cardiovascular disease treatment enters a new era. We here propose a radically different approach: implementing and evaluating in vivo a combinatorial library of nanoparticles with distinct physiochemical properties and differential immune cell specificities. The library's nanoparticles are based on endogenous high-density lipoprotein, which can preferentially deliver therapeutic compounds to pathological macrophages in atherosclerosis. Using the apolipoprotein E-deficient (Apoe

Topics: Animals; Anti-Inflammatory Agents; Apolipoproteins E; Atherosclerosis; Autoradiography; Benzoates; Benzylamines; Disease Models, Animal; Drug Delivery Systems; Female; Gene Expression Regulation; Immunotherapy; Lipoproteins, HDL; Macrophages; Mice; Mice, Inbred C57BL; Mice, Knockout; Molecular Imaging; Nanomedicine; Nanoparticles; Positron-Emission Tomography; RNA, Messenger

A novel series of 1,3-bistrifluoromethylcarbinol derivatives that act as liver X receptor (LXR) β-selective agonists was discovered. Structure-activity relationship studies led to the identification of molecule 62, which was more effective (Emax) and selective toward LXRβ than T0901317 and GW3965. Furthermore, 62 decreased LDL-C without elevating the plasma TG level and significantly suppressed the lipid-accumulation area in the aortic arch in a Bio F1B hamster fed a diet high in fat and cholesterol. We demonstrated that our LXRβ agonist would be potentially useful as a hypolipidemic and anti-atherosclerotic agent. In this manuscript, we report the design, synthesis and pharmacology of 1,3-bistrifluoromethylcarbinol derivatives.

Topics: Animals; Atherosclerosis; Benzoates; Benzylamines; Cricetinae; Drug Design; Humans; Hydrocarbons, Fluorinated; Hypolipidemic Agents; In Vitro Techniques; Lipid Metabolism; Liver; Liver X Receptors; Male; Methanol; Mice; Orphan Nuclear Receptors; Structure-Activity Relationship; Sulfonamides

Liver X receptor (LXR) signaling pathways regulate lipid metabolism and inflammation, which has generated widespread interest in developing synthetic LXR agonists as potential therapeutics for the management of atherosclerosis. In this study, it is demonstrated that nanoparticles (NPs) containing the synthetic LXR agonist GW3965 (NP-LXR) exert anti-inflammatory effects and inhibit the development of atherosclerosis without causing hepatic steatosis. These NPs are engineered through self-assembly of a biodegradable diblock poly(lactide-co-glycolide)-b-poly(ethylene glycol) (PLGA-b-PEG) copolymer. NP-LXR is significantly more effective than free GW3965 at inducing LXR-target gene expression and suppressing inflammatory factors in macrophages in vitro and in vivo. Additionally, the NPs elicit negligible lipogenic gene stimulation in the liver. Using the Ldlr (-/-) mouse model of atherosclerosis, abundant colocalization of fluorescently labeled NPs within plaque macrophages following systemic administration is seen. Notably, six intravenous injections of NP-LXR over 2 weeks markedly reduce the CD68-positive cell (macrophage) content of plaques (by 50%) without increasing total cholesterol or triglycerides in the liver and plasma. Together, these findings identify GW3965-encapsulated PLGA-b-PEG NPs as a promising nanotherapeutic approach to combat atherosclerosis, providing the benefits of LXR agonists without their adverse effects on hepatic and plasma lipid metabolism.

Topics: Animals; Anti-Inflammatory Agents; Atherosclerosis; Benzoates; Benzylamines; Cell Line; Gene Expression Regulation; Inflammation; Liver; Liver X Receptors; Male; Mice, Inbred C57BL; Nanoparticles; Orphan Nuclear Receptors; Plaque, Atherosclerotic

Liver X receptor (LXR) activators decrease atherosclerosis in mice. LXR activators (1) directly upregulate genes involved in reverse cholesterol transport and (2) exert anti-inflammatory effects mediated by transrepression of nuclear factor-κB target genes. We investigated whether myeloid cell deficiency of ATP-binding cassette transporters A1 and G1 (ABCA1/G1), principal targets of LXR that promote macrophage cholesterol efflux and initiate reverse cholesterol transport, would abolish the beneficial effects of LXR activation on atherosclerosis.. LXR activator T0901317 substantially reduced inflammatory gene expression in macrophages lacking ABCA1/G1. Ldlr(-/-) mice were transplanted with Abca1(-/-)Abcg1(-/-) or wild-type bone marrow (BM) and fed a Western-type diet for 6 weeks with or without T0901317 supplementation. Abca1/g1 BM deficiency increased atherosclerotic lesion complexity and inflammatory cell infiltration into the adventitia and myocardium. T0901317 markedly decreased lesion area, complexity, and inflammatory cell infiltration in the Abca1(-/-)Abcg1(-/-) BM-transplanted mice. To investigate whether this was because of macrophage Abca1/g1 deficiency, Ldlr(-/-) mice were transplanted with LysmCreAbca1(fl/fl)Abcg1(fl/fl) or Abca1(fl/fl)Abcg1(fl/fl) BM and fed Western-type diet with or without the more specific LXR agonist GW3965 for 12 weeks. GW3965 decreased lesion size in both groups, and the decrease was more prominent in the LysmCreAbca1(fl/fl)Abcg1(fl/fl) group.. The results suggest that anti-inflammatory effects of LXR activators are of key importance to their antiatherosclerotic effects in vivo independent of cholesterol efflux pathways mediated by macrophage ABCA1/G1. This has implications for the development of LXR activators that lack adverse effects on lipogenic genes while maintaining the ability to transrepress inflammatory genes.

Topics: Animals; Anti-Inflammatory Agents; Aorta; Atherosclerosis; ATP Binding Cassette Transporter 1; ATP Binding Cassette Transporter, Subfamily G, Member 1; ATP-Binding Cassette Transporters; Benzoates; Benzylamines; Biological Transport; Bone Marrow Transplantation; Cholesterol; Cytokines; Disease Models, Animal; Female; Gene Expression Regulation; Hydrocarbons, Fluorinated; Inflammation Mediators; Lipopolysaccharides; Lipoproteins; Liver X Receptors; Macrophages; Male; Mice; Mice, Inbred C57BL; Mice, Knockout; Myocardium; Orphan Nuclear Receptors; Receptors, LDL; Sulfonamides

Topics: Animals; Anti-Inflammatory Agents; Atherosclerosis; ATP Binding Cassette Transporter 1; ATP Binding Cassette Transporter, Subfamily G, Member 1; ATP-Binding Cassette Transporters; Benzoates; Benzylamines; Female; Hydrocarbons, Fluorinated; Lipoproteins; Liver X Receptors; Macrophages; Male; Orphan Nuclear Receptors; Receptors, LDL; Sulfonamides

LXRs have been of interest as targets for the treatment of atherosclerosis for over a decade. In recent years, LXR modulators have also garnered interest for potential use in the treatment of inflammation, Alzheimer's disease (AD), dermatological conditions, hepatic steatosis, and oncology. To date, no LXR modulator has successfully progressed beyond phase I clinical trials. In this Perspective, we summarize published medicinal chemistry efforts in the context of the available crystallographic data, druglikeness, and isoform selectivity. In addition, we discuss the challenges that need to be overcome before an LXR modulator can reach clinical use.

Topics: Anticholesteremic Agents; Atherosclerosis; Benzoates; Benzylamines; Binding Sites; Crystallography, X-Ray; Humans; Hydrocarbons, Fluorinated; Liver X Receptors; Models, Molecular; Molecular Structure; Orphan Nuclear Receptors; Protein Isoforms; Protein Structure, Tertiary; Sulfonamides

Liver X receptors (LXRs) are essential for the regulation of intestinal cholesterol absorption. Because two isoforms exist, LXRα and LXRβ, with overlapping but not identical functions, we investigated whether LXRα and LXRβ exert different effects on intestinal cholesterol absorption.. Wild-type (WT), LXRα(-/-) and LXRβ(-/-) mice were fed control diet, 0.2% cholesterol-enriched diet or 0.2% cholesterol-enriched diet plus the LXR agonist GW3965.. When fed a control diet, all three genotypes showed similar levels of cholesterol absorption. Of interest, a significant increase in cholesterol absorption was found in the LXRα(-/-) mice, but not in the WT or LXRβ(-/-) animals, when fed a diet enriched with 0.2% cholesterol or 0.2% cholesterol + GW3965. Reduced faecal neutral sterol excretion and a hydrophobic bile acid profile were also observed in LXRα(-/-) mice. Greater increases in the apolipoprotein (apo)B-containing lipoproteins in serum were seen in the LXRα(-/-) mice. A 0.2% cholesterol +GW3965 diet suppressed intestinal Npc1l1 protein expression to the same extent for all genotypes, while Abca1 and Abcg5 were elevated to the same degree.. In the intestine, LXRα and LXRβ seem to exert similar effects on expression of cholesterol-transporting proteins such as Npc1l1. Selective activation of LXRβ may generate effects such as increased cholesterol absorption and elevated serum levels of apoB-containing lipoproteins, which seem to be counteracted by LXRα. Therefore, an intestinal LXRβ-specific pathway might exist in terms of cholesterol transportation in addition to the main pathway.

Topics: Analysis of Variance; Animals; Atherosclerosis; ATP Binding Cassette Transporter, Subfamily G, Member 5; ATP-Binding Cassette Transporters; Benzoates; Benzylamines; Bile; Cholesterol; Cholesterol, Dietary; Intestinal Absorption; Intestine, Small; Lipid Metabolism; Lipoproteins; Liver; Liver X Receptors; Male; Membrane Transport Proteins; Mice; Mice, Knockout; Models, Animal; Orphan Nuclear Receptors; Protein Isoforms; Real-Time Polymerase Chain Reaction; RNA, Messenger

Liver X receptor (LXR) agonists are atheroprotective but often induce hypertriglyceridaemia and liver steatosis. We investigated the effect of a novel high-affinity LXR activator, AZ876, on plasma lipids, inflammation and atherosclerosis, and compared the effects with another LXR agonist, GW3965.. APOE*3Leiden mice were fed an atherogenic diet alone or supplemented with either AZ876 (5 or 20µmol·kg(-1) ·day(-1) ) or GW3965 (17µmol·kg(-1) ·day(-1) ) for 20 weeks. Total cholesterol and triglyceride levels were measured using commercial kits. Plasma cytokines were determined by using bead-based multiplex suspension array kits with the Luminex technology. Atherosclerosis was assessed histochemically and lesion composition was assessed by immunohistochemical methods.. Low-dose AZ876 had no effect on plasma or liver lipids, whereas high-dose AZ876 increased plasma triglycerides (+110%) and reduced cholesterol (-16%) compared with controls. GW3965 increased plasma triglycerides (+70%). Low-dose AZ876 reduced lesion area (-47%); and high-dose AZ876 strongly decreased lesion area (-91%), lesion number (-59%) and severity. In either dose, AZ876 did not affect lesion composition. GW3965 reduced atherosclerosis and collagen content of lesions (-23%; P < 0.01). High-dose AZ876 and GW3965, but not low-dose AZ876, reduced inflammation as reflected by lower cytokine levels and vessel wall activation.. We have identified a novel LXR agonist that when given in a low dose inhibits the progression of atherosclerosis without inducing anti-inflammatory effects, liver steatosis or hypertriglyceridaemia. Therefore, the primary protective action of a low-dose AZ876 is likely to be an increased reverse cholesterol transport.

Topics: Aniline Compounds; Animals; Apolipoprotein E3; Atherosclerosis; Benzoates; Benzylamines; Cholesterol; Cytokines; Dose-Response Relationship, Drug; Fatty Liver; Female; Humans; Hypertriglyceridemia; Inflammation; Lipid Metabolism; Lipids; Liver; Liver X Receptors; Mice; Mice, Inbred C57BL; Mice, Transgenic; Orphan Nuclear Receptors; Thiazoles; Triglycerides

Liver X receptors (LXRs) are transcription factors involved in the regulation of cholesterol homeostasis. LXR ligands have athero-protective properties independent of their effects on cholesterol metabolism. Platelets are involved in the initiation of atherosclerosis and despite being anucleate express nuclear receptors. We hypothesized that the athero-protective effects of LXR ligands could be in part mediated through platelets and therefore explored the potential role of LXR in platelets. Our results show that LXR-β is present in human platelets and the LXR ligands, GW3965 and T0901317, modulated nongenomically platelet aggregation stimulated by a range of agonists. GW3965 caused LXR to associate with signaling components proximal to the collagen receptor, GPVI, suggesting a potential mechanism of LXR action in platelets that leads to diminished platelet responses. Activation of platelets at sites of atherosclerotic lesions results in thrombosis preceding myocardial infarction and stroke. Using an in vivo model of thrombosis in mice, we show that GW3965 has antithrombotic effects, reducing the size and the stability of thrombi. The athero-protective effects of GW3965, together with its novel antiplatelet/thrombotic effects, indicate LXR as a potential target for prevention of athero-thrombotic disease.

Topics: Animals; Atherosclerosis; Benzoates; Benzylamines; Calcium; Flow Cytometry; Humans; Hydrocarbons, Fluorinated; Immunoblotting; Immunoprecipitation; Ligands; Liver X Receptors; Mice; Mice, Inbred C57BL; Orphan Nuclear Receptors; Platelet Aggregation; Platelet Glycoprotein GPIIb-IIIa Complex; Platelet Membrane Glycoproteins; Sulfonamides; Thrombosis

A series of phenyl sulfone substituted quinoxaline were prepared and the lead compound 13 (WYE-672) was shown to be a tissue selective LXR Agonist. Compound 13 demonstrated partial agonism for LXRbeta in kidney HEK-293 cells but did not activate Gal4 LXRbeta fusion proteins in huh-7 liver cells. Although 13 showed potent binding affinity to LXRbeta (IC(50) = 53 nM), it had little binding affinity for LXRalpha (IC(50) > 1.0 microM) and did not recruit any coactivator/corepressor peptides in the LXRalpha multiplex assay. However, compound 13 showed good agonism in THP-1 cells with respect to increasing ABCA1 gene expression and good potency on cholesterol efflux in THP-1 foam cells. In an eight-week lesion study in LDLR -/- mice, compound 13 showed reduction of aortic arch lesion progression and no plasma or hepatic triglyceride increase. These results suggest quinoxaline 13 may have an improved biological profile for potential use as a therapeutic agent.

Topics: Animals; Area Under Curve; Atherosclerosis; ATP Binding Cassette Transporter 1; ATP-Binding Cassette Transporters; Cell Line; Cholesterol; Duodenum; Half-Life; Humans; Kidney; Liver; Liver X Receptors; Male; Mice; Mice, Inbred C57BL; Mice, Knockout; Models, Molecular; Organ Specificity; Orphan Nuclear Receptors; Quinoxalines; Radioligand Assay; Structure-Activity Relationship; Sulfones; Transcriptional Activation; Triglycerides

Chlamydia pneumoniae is detected by macrophages and other APCs via TLRs and can exacerbate developing atherosclerotic lesions, but how that occurs is not known. Liver X receptors (LXRs) centrally control reverse cholesterol transport, but also negatively modulate TLR-mediated inflammatory pathways. We isolated peritoneal macrophages from wild-type, TLR2, TLR3, TLR4, TLR2/4, MyD88, TRIF, MyD88/TRIF, and IFN regulatory factor 3 (IRF3) KO mice, treated them with live or UV-killed C. pneumoniae in the presence or absence of oxidized LDL, then measured foam cell formation. In some experiments, the synthetic LXR agonist GW3965 was added to macrophages infected with C. pneumoniae in the presence of oxidized LDL. Both live and UV-killed C. pneumoniae induced IRF3 activation and promoted foam cell formation in wild-type macrophages, whereas the genetic absence of TLR2, TLR4, MyD88, TRIF, or IRF3, but not TLR3, significantly reduced foam cell formation. C. pneumoniae-induced foam cell formation was significantly reduced by the LXR agonist GW3965, which in turn inhibited C. pneumoniae-induced IRF3 activation, suggesting a bidirectional cross-talk. We conclude that C. pneumoniae facilitates foam cell formation via activation of both MyD88-dependent and MyD88-independent (i.e., TRIF-dependent and IRF3-dependent) pathways downstream of TLR2 and TLR4 signaling and that TLR3 is not involved in this process. This mechanism could at least partly explain why infection with C. pneumoniae accelerates the development of atherosclerotic plaque and lends support to the proposal that LXR agonists might prove clinically useful in suppressing atherogenesis.

Topics: Animals; Atherosclerosis; Benzoates; Benzylamines; Chlamydia Infections; Chlamydophila pneumoniae; DNA-Binding Proteins; Foam Cells; Interferon Regulatory Factor-3; Lipoproteins, LDL; Liver X Receptors; Mice; Mice, Knockout; Myeloid Differentiation Factor 88; NF-kappa B; Orphan Nuclear Receptors; Receptors, Cytoplasmic and Nuclear; Signal Transduction; Toll-Like Receptors

A series of phenyl acetic acid based quinolines was prepared as LXR modulators. An SAR study in which the C-3 and C-8 positions of the quinoline core were varied led to the identification of two potent LXR agonists 23 and 27. Both compounds displayed good binding affinity for LXRbeta and LXRalpha, and increased expression of ABCA1 in THP-1 cells. These two compounds also had desirable pharmacokinetic profiles in mice and displayed in vivo efficacy in a 12-week Apo E knockout mouse lesion model.

Topics: Animals; Apolipoproteins E; Atherosclerosis; Carboxylic Acids; CHO Cells; Chromatography, High Pressure Liquid; Cricetinae; Cricetulus; DNA-Binding Proteins; Humans; Indicators and Reagents; Liver X Receptors; Magnetic Resonance Spectroscopy; Male; Mice; Mice, Inbred C57BL; Mice, Knockout; Orphan Nuclear Receptors; Phenylacetates; Quinolines; Receptors, Cytoplasmic and Nuclear; Recombinant Proteins; Solvents; Spectrometry, Mass, Electrospray Ionization; Structure-Activity Relationship; Transcriptional Activation

A structure-based approach was used to optimize our new class of quinoline LXR modulators leading to phenyl acetic acid substituted quinolines 15 and 16. Both compounds displayed good binding affinity for LXRbeta and LXRalpha and were potent activators in LBD transactivation assays. The compounds also increased expression of ABCA1 and stimulated cholesterol efflux in THP-1 cells. Quinoline 16 showed good oral bioavailability and in vivo efficacy in a LDLr knockout mouse model for lesions.

Topics: Animals; Anticholesteremic Agents; Atherosclerosis; ATP Binding Cassette Transporter 1; ATP-Binding Cassette Transporters; Binding Sites; Biological Availability; Cell Line; Cholesterol; DNA-Binding Proteins; Drug Stability; Female; Humans; In Vitro Techniques; Ligands; Liver X Receptors; Male; Mice; Mice, Inbred C57BL; Microsomes, Liver; Models, Molecular; Molecular Structure; Orphan Nuclear Receptors; Phenylacetates; Protein Structure, Tertiary; Quinolines; Receptors, Cytoplasmic and Nuclear; Structure-Activity Relationship; Transcriptional Activation