CD36 is a multi-ligand scavenger receptor present on the surface of a number of cells such as platelets, monocytes/macrophages, endothelial and smooth muscle cells. Monocyte/macrophage CD36 has been shown to play a critical role in the development of atherosclerotic lesions by its capacity to bind and endocytose oxidized low density lipoproteins (OxLDL), and it is implicated in the formation of foam cells. However, the significance of CD36 in atherosclerosis has recently been called into question by different studies, and therefore its exact role still needs to be clarified. The aim of this article is to carefully review the importance of CD36 as an essential component in the pathogenesis of atherosclerosis. © 2007 European Society of Cardiology. Published by Elsevier B.V. All rights reserved.Keywords: CD36; Vascular; Monocyte/macrophages; OxLDL; Atherosclerosis Atherosclerosis is a progressive chronic inflammatory disease characterised by a gradual thickening and hardening of arteries that ultimately leads to a reduction in the lumen diameter and potentially to ischemia following plaque rupture. A first stage of the disease is the presence of dysfunctional endothelial cells (EC) which via activated adhesion molecules and expressed chemokines recruit circulating monocytes and a subpopulation of lymphocytes (CD4/CD8) into the intima. Endothelial dysfunction may be induced by oxidized low density lipoproteins (OxLDL). Indeed, LDL when infiltrating into the intima can be readily oxidized by resident macrophages or endothelial cells. Moreover, C-reactive protein (CRP) and OxLDL can act synergistically to increase monocytes inflammatory properties (through MCP-1, PGE2, MMP-1 production) and attract further circulating monocytes through the release of MCP-1 to adhere to the activated dysfunctional endothelial cells and extravasate to the intima to scavenge OxLDL [1]. One of the involvements of CD36 in lesion development is its ability to bind and endocytose OxLDL into macrophages, as a scavenger receptor, and ultimately be implicated in the differentiation of resident macrophages into foam cells that constitute the atherosclerotic lesion core.CD36 is an 88-kD membrane glycoprotein that was first identified on monocytes by monoclonal antibody OKM5 [2] and then subsequently isolated from blood platelets [3,4]. This membrane glycoprotein is expressed by many celltypes including microvasculature endothelial [5] and smooth muscle cells (SMC) [6]. Functional and structural characterisation showed CD36 to be a member of the scavenger receptor class B family with a capacity to bind OxLDL as well as various other ligands. The importance of monocytic CD36 in the initiation and perpetuation of atherosclerotic lesions was shown over this past decade by its effect in significantly reducing the size of vascular lesions when
Unbiased metagenomic sequencing holds significant potential as a diagnostic tool for the simultaneous detection of any previously genetically described viral nucleic acids in clinical samples. Viral genome sequences can also inform on likely phenotypes including drug susceptibility or neutralization serotypes. In this study, different variables of the laboratory methods often used to generate viral metagenomics libraries on the efficiency of viral detection and virus genome coverage were compared. A biological reagent consisting of 25 different human RNA and DNA viral pathogens was used to estimate the effect of filtration and nuclease digestion, DNA/RNA extraction methods, pre-amplification and the use of different library preparation kits on the detection of viral nucleic acids. Filtration and nuclease treatment led to slight decreases in the percentage of viral sequence reads and number of viruses detected. For nucleic acid extractions silica spin columns improved viral sequence recovery relative to magnetic beads and Trizol extraction. Pre-amplification using random RT-PCR while generating more viral sequence reads resulted in detection of fewer viruses, more overlapping sequences, and lower genome coverage. The ScriptSeq library preparation method retrieved more viruses and a greater fraction of their genomes than the TruSeq and Nextera methods. Viral metagenomics sequencing was able to simultaneously detect up to 22 different viruses in the biological reagent analyzed including all those detected by qPCR. Further optimization will be required for the detection of viruses in biologically more complex samples such as tissues, blood, or feces.
Obesity induced by Western diets is associated with type 2 diabetes mellitus and cardiovascular diseases, although underlying mechanisms are unclear. We investigated a murine model of diet-induced obesity to determine the effect of transient potential receptor vanilloid 1 (TRPV1) deletion on hypertension and metabolic syndrome. Wild-type and TRPV1 knockout mice were fed normal or high-fat diet from 3 to 15 weeks. High-fat diet-fed mice from both genotypes became obese, with similar increases in body and adipose tissue weights. High-fat diet-fed TRPV1 knockout mice showed significantly improved handling of glucose compared with high-fat diet-fed wild-type mice. Hypertension, vascular hypertrophy, and altered nociception were observed in high-fat diet-fed wild-type but not high-fat diet-fed TRPV1 knockout mice. Wild-type, but not high-fat diet-fed TRPV1 knockout, mice demonstrated remodeling in terms of aortic vascular hypertrophy and increased heart and kidney weight, although resistance vessel responses were similar in each. Moreover, the wild-type mice had significantly increased plasma levels of leptin, interleukin 10 and interleukin 1β, whereas samples from TRPV1 knockout mice did not show significant increases. Our results do not support the concept that TRPV1 plays a major role in influencing weight gain. However, we identified a role of TRPV1 in the deleterious effects observed with high-fat feeding in terms of inducing hypertension, impairing thermal nociception sensitivity, and reducing glucose tolerance. The observation of raised levels of adipokines in wild-type but not TRPV1 knockout mice is in keeping with TRPV1 involvement in stimulating the proinflammatory network that is central to obesity-induced hypertension and sensory neuronal dysfunction.
Human tumor suppressor protein p53 plays a major role in the cell cycle, orchestrating a number of important genes involved in cell-cycle control and apoptosis, and seems to be one of the most important molecules protecting cells from malignant transformation. Mutations in the p53 gene are observed in about 50% of primary tumors, inducing defective p53 protein no longer capable of binding DNA and of activating transcription. Certain DNA viruses are thought to act in a similar way and may also contribute to the progression of invasive cancer in infected tissue. One of the most effective strategies employed by these viruses is the inhibition of p53 protein by interaction with viral oncoproteins, implying a direct but also an indirect role of these viruses in the impairment of p53 structure and function. This article provides a summary of current knowledge concerning p53 tumor suppressor protein and reviews the different mechanisms adopted by different DNA viruses in undermining p53 function.
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