ABSTRACT
Oxidative low-density lipoprotein (Ox-LDL) is a key risk factor for the development of atherosclerosis, and it can stimulate the expression of a variety of inflammatory signals. As a new and highly sensitive inflammation index, OX40L may be a key to understanding the mechanisms that regulate interactions between cells within the vessel wall and inflammatory mediators during the development of atherosclerosis. To investigate whether Ox-LDL regulates OX40L expression through an oxidized LDL-1 receptor (LOX-1)-mediated mechanism, we investigated the effect of different concentrations of Ox-LDL (50, 100, 150 µg/mL) on endothelial cell proliferation and apoptosis. Stimulation with Ox-LDL increased OX40L protein 1.44-fold and mRNA 4.0-fold in endothelial cells, and these effects were inhibited by blocking LOX-1. These results indicate that LOX-1 plays an important role in the chronic inflammatory process in blood vessel walls. Inhibiting LOX-1 may reduce blood vessel inflammation and provide a therapeutic option to limit atherosclerosis progression.
Subject(s)
Humans , Apoptosis/drug effects , Cell Proliferation/drug effects , Human Umbilical Vein Endothelial Cells/drug effects , Lipoproteins, LDL/pharmacology , /metabolism , Scavenger Receptors, Class E/metabolism , Atherosclerosis/etiology , Atherosclerosis/prevention & control , Cell Cycle , Cells, Cultured , Human Umbilical Vein Endothelial Cells/cytology , Human Umbilical Vein Endothelial Cells/metabolism , Immunoblotting , Lipoproteins, LDL/metabolism , Lipoproteins, LDL/physiology , /genetics , Real-Time Polymerase Chain Reaction , Signal Transduction , Vasculitis/physiopathology , Vasculitis/prevention & controlABSTRACT
Astaxanthin, a high-value ketocarotenoid is mainly used in fish aquaculture. It also has potential in human health due to its higher antioxidant capacity than beta-carotene and vitamin E. The unicellular green alga Haematococcus pluvialis is known to accumulate astaxanthin in response to environmental stresses, such as high light intensity and salt stress. Carotenoid hydroxylase plays a key role in astaxanthin biosynthesis in H. pluvialis. In this paper, we report the characterization of a promoter-like region (-378 to -22 bp) of carotenoid hydroxylase gene by cloning, sequence analysis and functional verification of its 919 bp 5'-flanking region in H. pluvialis. The 5'-flanking region was characterized using micro-particle bombardment method and transient expression of LacZ reporter gene. Results of sequence analysis showed that the 5'-flanking region might have putative cis-acting elements, such as ABA (abscisic acid)-responsive element (ABRE), C-repeat/dehydration responsive element (C-repeat/DRE), ethylene-responsive element (ERE), heat-shock element (HSE), wound-responsive element (WUN-motif), gibberellin-responsive element (P-box), MYB-binding site (MBS) etc., except for typical TATA and CCAAT boxes. Results of 5' deletions construct and beta-galactosidase assays revealed that a highest promoter-like region might exist from -378 to -22 bp and some negative regulatory elements might lie in the region from -919 to -378 bp. Results of site-directed mutagenesis of a putative C-repeat/DRE and an ABRE-like motif in the promoter-like region (-378 to -22 bp) indicated that the putative C-repeat/DRE and ABRE-like motif might be important for expression of carotenoid hydroxylase gene.
Subject(s)
Chlorophyta/enzymology , Base Sequence , Binding Sites , Cloning, Molecular , Gene Deletion , Lac Operon , Mixed Function Oxygenases/biosynthesis , Molecular Sequence Data , Mutagenesis, Site-Directed , Mutation , Plasmids/metabolism , Promoter Regions, GeneticABSTRACT
Acute suppurative otitis media of guinea pigs had been induced by inoculation of Staphylococcus aureus in the bulla. The permeability of the round window membrane to endotoxin was investigated by detecting endotoxin of the perilymph, applied to the round window using limulus amebocyte lysate test. It was found that endotoxin could pass through round window membranes of animals. With inflammation of middle ear, the permeability of the round window membrane to endotoxin was increased. These results suggest that bacterial toxins and the consequential migration of chemical inflammatory mediators might act as promoting factors of round window membrane permeability