Nonglucuronidated Ezetimibe Disrupts CD13- and CD64-Coassembly in Membrane Microdomains and Decreases Cellular Cholesterol Content in Human Monocytes/Macrophages.

Ezetimibe (EZE) and glucuronidated EZE (EZE-Glu) differentially target Niemann-Pick C1-like 1 (NPC1L1) and CD13 (aminopeptidase-N) to inhibit intestinal cholesterol absorption and cholesterol processing in other cells, although the precise molecular mechanisms are not fully elucidated. Cellular effects of EZE, EZE-Glu, and the low-absorbable EZE-analogue S6130 were investigated on human monocyte-derived macrophages upon loading with atherogenic lipoproteins. EZE and S6130, but not EZE-Glu disturbed the colocalization of CD13 and its coreceptor CD64 (Fcγ receptor I) in membrane microdomains, and decreased the presence of both receptors in detergent-resistant membrane fractions.

Postprandial triglyceride-rich lipoproteins regulate perilipin-2 and perilipin-3 lipid-droplet-associated proteins in macrophages.

Lipid accumulation in macrophages contributes to atherosclerosis. Within macrophages, lipids are stored in lipid droplets (LDs); perilipin-2 and perilipin-3 are the main LD-associated proteins. Postprandial triglyceride (TG)-rich lipoproteins induce LD accumulation in macrophages.

Specific gene expression responses to parasite genotypes reveal redundancy of innate immunity in vertebrates.

Vertebrate innate immunity is the first line of defense against an invading pathogen and has long been assumed to be largely unspecific with respect to parasite/pathogen species. However, recent phenotypic evidence suggests that immunogenetic variation, i.e.

3β,5α,6β-Cholestanetriol and 25-hydroxycholesterol accumulate in ATP-binding cassette transporter G1 (ABCG1)-deficiency.

Objective: Oxysterols are oxidized derivatives of sterols that have cytotoxic effects and are potent regulators of diverse cellular functions. Efficient oxysterol removal by the sub-family G member 1 of the ATP-binding cassette transporters (ABCG1) is essential for cell survival and control of cellular processes. However, the specific role of ABCG1 in the transport of various oxysterol species has been not systematically investigated to date.

Neutral lipid stores and lipase PNPLA5 contribute to autophagosome biogenesis.

Background: Autophagy is a fundamental cell biological process whereby eukaryotic cells form membranes in the cytoplasm to sequester diverse intracellular targets. Although significant progress has been made in understanding the origins of autophagosomal organelles, the source of lipids that support autophagic membrane formation remain an important open question.

Results: Here we show that lipid droplets as cellular stores of neutral lipids including triglycerides contribute to autophagic initiation.

Paradoxical effects on force generation after efficient β1-adrenoceptor knockdown in reconstituted heart tissue.

Stimulation of myocardial β(1)-adrenoceptors (AR) is a major mechanism that increases cardiac function. We investigated the functional consequences of genetic β(1)-AR knockdown in three-dimensional engineered heart tissue (EHT). For β(1)-AR knockdown, short interfering RNA (siRNA) sequences targeting specifically the β(1)-AR (shB1) and a scrambled control (shCTR) were subcloned into a recombinant adeno-associated virus (AAV)-short hairpin RNA (shRNA) expression system.

DNA methyltransferase inhibition reverses epigenetically embedded phenotypes in lung cancer preferentially affecting polycomb target genes.

Purpose: Cancer cell phenotypes are partially determined by epigenetic specifications, such as DNA methylation. Metastasis development is a late event in cancerogenesis and might be associated with epigenetic alterations.

Experimental Design: An in vivo selection approach was used to generate highly aggressive non-small cell lung cancer (NSCLC) cell lines (A549 and HTB56) followed by genome-wide DNA methylation analysis.

Postgwas: advanced GWAS interpretation in R.

We present a comprehensive toolkit for post-processing, visualization and advanced analysis of GWAS results. In the spirit of comparable tools for gene-expression analysis, we attempt to unify and simplify several procedures that are essential for the interpretation of GWAS results. This includes the generation of advanced Manhattan and regional association plots including rare variant display as well as novel interaction network analysis tools for the investigation of systems-biology aspects.

A genome-wide association study identifies a gene network of ADAMTS genes in the predisposition to pediatric stroke.

Pediatric stroke is a rare but highly penetrant disease with a strong genetic background. Although there are an increasing number of genome-wide association studies (GWASs) for stroke in adults, such studies for stroke of pediatric onset are lacking. Here we report the results of the first GWAS on pediatric stroke using a large cohort of 270 family-based trios.

Evolutionary dynamics of co-segregating gene clusters associated with complex diseases.

Background: The distribution of human disease-associated mutations is not random across the human genome. Despite the fact that natural selection continually removes disease-associated mutations, an enrichment of these variants can be observed in regions of low recombination. There are a number of mechanisms by which such a clustering could occur, including genetic perturbations or demographic effects within different populations.

SR-PSOX at sites predisposed to atherosclerotic lesion formation mediates monocyte-endothelial cell adhesion.

Objective: The scavenger receptor SR-PSOX/CXCL16, which is identical to the chemokine CXCL16, is thought to be involved in atherogenesis. However, the presence and function of SR-PSOX/CXCL16 in the endothelium of atherosclerotic arteries has not been substantiated.

Methods And Results: In rabbit aorta immunocytochemistry revealed SR-PSOX/CXCL16 primarily in the endothelium at sites predisposed to lesion formation, in the endothelium of early atherosclerotic lesions, and mainly in intimal macrophages of more developed lesions, indicating that SR-PSOX/CXCL16-expression shifts during atherogenesis.

Topography of lipid droplet-associated proteins: insights from freeze-fracture replica immunogold labeling.

Lipid droplets are not merely storage depots for superfluous intracellular lipids in times of hyperlipidemic stress, but metabolically active organelles involved in cellular homeostasis. Our concepts on the metabolic functions of lipid droplets have come from studies on lipid droplet-associated proteins. This realization has made the study of proteins, such as PAT family proteins, caveolins, and several others that are targeted to lipid droplets, an intriguing and rapidly developing area of intensive inquiry.

Lipid droplet associated proteins: an emerging role in atherogenesis.

Coronary heart disease and stroke, caused by rupture of atherosclerotic plaques in the arterial wall, are the major causes of death in industrialized countries. A key event in the pathogenesis of atherosclerosis is the transformation of smooth muscle cells and in particular of macrophages into foam cells, a result of massive accumulation of lipid droplets. It is well known that the formation of these lipid droplets is a result of the uninhibited uptake of modified lipoproteins by scavenger receptors.

Apolipoprotein E induces antiinflammatory phenotype in macrophages.

Objective: Apolipoprotein E (apoE) exerts potent antiinflammatory effects. Here, we investigated the effect of apoE on the functional phenotype of macrophages.

Methods And Results: Human apoE receptors very-low-density lipoprotein receptor (VLDL-R) and apoE receptor-2 (apoER2) were stably expressed in RAW264.

Lipid droplet growth by fusion: insights from freeze-fracture imaging.

An understanding of how lipid droplets grow in the cell is important to current human health issues. Homotypic fusion of small lipid droplets to create larger ones is one proposed mechanism though the evidence for this process continues to be debated. By applying the technique of freeze-fracture electron microscopy to cells that have been stimulated to accumulate lipid droplets, we here present images which suggest that at least some large lipid droplets may indeed result from amalgamation of multiple smaller ones.

Identification and functional analyses of molecular haplotypes of the human osteoprotegerin gene promoter.

Objective: Osteoprotegerin (OPG) has been reported to be involved in the development of atherosclerotic disease, and OPG gene variation has been associated with plasma OPG levels and different cardiovascular disease phenotypes. However, the genetic architecture of the OPG promoter and its transcriptional regulation are poorly characterized.

Methods And Results: We identified 1008 bp of the OPG 5'-flanking region to be sufficiently transcriptionally active in osteosarcoma cell lines and generated serial promoter deletion constructs.

Susceptibility genes & modifiers for cardiac arrhythmias.

Cardiac arrhythmias in the absence of structural heart diseases can be subdivided in those cases which are acquired and those which are linked to genetic defects on cardiac ion channels and regulatory subunits. Although acquired arrhythmias do not contain any obviously genetic component the observation of frequently occurring single nucleotide polymorphism (SNPs) identified in cardiac ion channel genes lead to the question if these natural variants can influence the development of acquired forms of cardiac arrhythmias and thus serve as genetic susceptibility markers. This review summarizes the results of genetic association and linkage studies in drug induced long-QT syndrome and atrial and ventricular fibrillation and discusses advantages and future directions of this topic in cardiac research.

TIP47, a lipid cargo protein involved in macrophage triglyceride metabolism.

Objective: Uptake of lipids by macrophages (MPhi) leads to lipid droplet accumulation and foam cell formation. The PAT family proteins are implicated in lipid droplet formation, but the precise function of the 47-kDa tail interacting protein (TIP47), a member of this family, is poorly defined. The present study was performed to determine the function of TIP47 in MPhi lipid metabolism.

Osteopontin gene variation and cardio/cerebrovascular disease phenotypes.

We aimed at associating common osteopontin (OPN) gene variants with cardiovascular disease phenotypes.We scanned the OPN gene in 190 chromosomes from myocardial infarction (MI) patients and identified five variants in the promoter, three synonymous and one non-synonymous variant. All variants were investigated in case-control studies for MI (ECTIM: 990 cases, 900 controls) and brain infarction (BI) (GENIC: 466 cases, 444 controls).

Compartmentalization of proteins in lipid droplet biogenesis.

Our existing understanding of the structure, protein organization and biogenesis of the lipid droplet has relied heavily on microscopical techniques that lack resolution and the ability to preserve native cellular and protein composition. The electron microscopic technique of freeze-fracture replica immunogold labeling (FRIL) overcomes these problems, and is currently providing new perspectives in the field. Because of the property of frozen lipids to deflect the fracture plane, en face views of the lipid droplet and its component layers are revealed for high resolution visualization.

Molecular genetic analysis of a human insulin-like growth factor 1 promoter P1 variation.

Insulin-like growth factor 1 (IGF1) exerts important endocrine and paracrine functions in the cardiovascular system. We identified the common variant -1411C>T in the IGF1 upstream promoter P1, located within several overlapping transcription factor binding sites. Using transient transfection assays, we identified this site as a functional enhancer.

Atorvastatin therapy is associated with reduced levels of N-terminal prohormone brain natriuretic peptide and improved cardiac function in patients with heart failure.

Background: Statins have been suggested to improve cardiac function, but the evidence underlying beneficial effects of statins in heart failure (HF) is insufficient. We analyzed plasma N-terminal prohormone brain natriuretic peptide (NT-proBNP) levels and cardiac function in patients with HF of various etiologies, and who were treated with or without statins.

Hypothesis: Statin treatment is associated with improved cardiac function in HF.

Genes, diet and public health.

Common chronic diseases such as coronary heart disease (CHD), diabetes, cancer, hypertension and obesity are significantly influenced by dietary and other behavioural habits. There is increasing scientific evidence that genetic factors (SNPs), conferring either protection or risk, also contribute importantly to the incidence of these diseases. SNPs are of particular interest because they influence disease in a complex but largely unknown manner by interacting with environmental and lifestyle factors.

Vascular remodeling in ApoE-deficient mice: diet dependent modulation after carotid ligation.

Vascular remodeling is influenced by trauma and proatherogenic factors such as cholesterol. It has been shown that cholesterol exerts a direct effect on vessel wall structure. In this study we evaluated the effects of vascular trauma and cholesterol treatment on vascular remodeling and plaque integrity in carotid ligated ApoE-deficient mice.

Molecular investigation of the functional relevance of missense variants of ICAM-1.

In genome-wide studies, the intercellular adhesion molecule-1 (ICAM-1) locus has been associated with cardiovascular and inflammatory bowel diseases. To determine the functional relevance of five missense ICAM-1 variants (G241R; I316V; P352L; K469E; R478W), we generated wild-type and variant proteins [M2(241R); M3(469E); M4(352L); M5(478W); M6(316V); M7(352L/469E)] and transiently transfected CV1 cells. Reverse transcription PCR, western blot, and ELISA did not reveal any differences in mRNA and protein expression levels for any construct.