Objective-To investigate whether high-density lipoproteins (HDLs) suppress chemokine (CCL2, CCL5, and CX 3 CL1) and chemokine receptor (CCR2 and CX 3 CR1) expression, a mechanism for the atheroprotective properties of HDLs. Methods and Results-Apolipoprotein (apo) EϪ/Ϫ mice were fed a high-fat diet for 12 weeks. Before being euthanized, the mice received 5 consecutive daily injections of lipid-free apoA-I, 40 mg/kg, or saline (control). The injection of apoA-I reduced CCR2 and CX 3 CR1 expression in plaques compared with controls (PϽ0.05). ApoA-I-injected mice had lower plasma CCL2 and CCL5 levels. Hepatic CCL2, CCL5, and CX 3 CL1 levels were also reduced (PϽ0.05). In vitro studies found that reconstituted HDL (rHDL) reduced monocyte CCR2 and CX 3 CR1 expression and inhibited their migration toward CCL2 and CX 3 CL1 (PϽ0.05). Preincubation with rHDL reduced CCL2, CCL5, and CX 3 CL1 expression in monocytes and human coronary artery endothelial cells. The stimulation of CX 3 CR1 with peroxisome proliferator-activated receptor ␥ agonist CAY10410 was suppressed by preincubation with rHDL but did not affect the peroxisome proliferator-activated receptor ␥ antagonist (GW9664)-mediated increase in CCR2. In monocytes and human coronary artery endothelial cells, rHDL reduced the expression of the nuclear p65 subunit, IB kinase activity, and the phosphorylation of IB␣ (PϽ0.05). Key Words: high-density lipoproteins Ⅲ inflammation Ⅲ chemokines Ⅲ chemokine receptors Ⅲ atherosclerosis H igh-density lipoproteins (HDLs) are atheroprotective. 1 Human and animal intervention studies have found that infusion of reconstituted HDL (rHDL) or overexpression of apolipoprotein (apo) A-I reduces atherosclerotic plaque size 2 and macrophage and lipid content. [3][4][5][6] The mechanisms for this have been predominantly attributed to reverse cholesterol transport. However, HDLs also have potent anti-inflammatory properties. 7 For example, HDLs reduce endothelial expression of adhesion molecules, such as vascular cell adhesion molecule-1 and intercellular adhesion molecule-1. This project seeks to investigate if HDLs also reduce the expression of chemokines and their receptors, which are key mediators of inflammatory processes and atherosclerotic lesion development. Conclusion-Lipid-freeIn the early stages of atherosclerosis, chemokines and chemokine receptors are critical for the recruitment of circulating monocytes to the endothelium and assist in their migration into the artery wall. 8 The monocytes differentiate into macrophages and express more chemokines, thereby exacerbating the disease process. 8 The importance of the chemokine receptors (CCR2 and CX 3 CR1) and the chemokines (CCL2 [monocyte chemotactic protein-1], CCL5 [regulated upon activation, normal T-cell expressed, and secreted (RANTES)], and CX 3 CL1 [fractalkine]) in atherosclerosis has been demonstrated in human studies and animal knockout models. For example, CCR2Ϫ/Ϫ and CX 3 CR1 Ϫ/Ϫ mice, crossed with apoE Ϫ/Ϫ mice, develop smaller atherosclerotic plaques 9 -11 ; and ...

BackgroundMicrobiome/host interactions describe characteristics that affect the host's health. Shotgun metagenomics includes sequencing a random subset of the microbiome to analyze its taxonomic and metabolic potential. Reconstruction of DNA fragments into genomes from metagenomes (called metagenome-assembled genomes) assigns unknown fragments to taxa/function and facilitates discovery of novel organisms. Genome reconstruction incorporates sequence assembly and sorting of assembled sequences into bins, characteristic of a genome. However, the microbial community composition, including taxonomic and phylogenetic diversity may influence genome reconstruction. We determine the optimal reconstruction method for four microbiome projects that had variable sequencing platforms (IonTorrent and Illumina), diversity (high or low), and environment (coral reefs and kelp forests), using a set of parameters to select for optimal assembly and binning tools.MethodsWe tested the effects of the assembly and binning processes on population genome reconstruction using 105 marine metagenomes from 4 projects. Reconstructed genomes were obtained from each project using 3 assemblers (IDBA, MetaVelvet, and SPAdes) and 2 binning tools (GroopM and MetaBat). We assessed the efficiency of assemblers using statistics that including contig continuity and contig chimerism and the effectiveness of binning tools using genome completeness and taxonomic identification.ResultsWe concluded that SPAdes, assembled more contigs (143,718 ± 124 contigs) of longer length (N50 = 1632 ± 108 bp), and incorporated the most sequences (sequences-assembled = 19.65%). The microbial richness and evenness were maintained across the assembly, suggesting low contig chimeras. SPAdes assembly was responsive to the biological and technological variations within the project, compared with other assemblers. Among binning tools, we conclude that MetaBat produced bins with less variation in GC content (average standard deviation: 1.49), low species richness (4.91 ± 0.66), and higher genome completeness (40.92 ± 1.75) across all projects. MetaBat extracted 115 bins from the 4 projects of which 66 bins were identified as reconstructed metagenome-assembled genomes with sequences belonging to a specific genus. We identified 13 novel genomes, some of which were 100% complete, but show low similarity to genomes within databases.ConclusionsIn conclusion, we present a set of biologically relevant parameters for evaluation to select for optimal assembly and binning tools. For the tools we tested, SPAdes assembler and MetaBat binning tools reconstructed quality metagenome-assembled genomes for the four projects. We also conclude that metagenomes from microbial communities that have high coverage of phylogenetically distinct, and low taxonomic diversity results in highest quality metagenome-assembled genomes.Electronic supplementary materialThe online version of this article (10.1186/s12864-017-4294-1) contains supplementary material, which is available to authorized users.

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