Assay for advanced glycation end products generating intracellular oxidative stress through binding to its receptor.

Advanced glycation end products (AGEs) are a heterogenous group of glycation adducts on amino acids produced with sugars or dicarbonyls. Intracellular inflammation triggered by binding of AGEs to receptor for AGEs (RAGE) is linked to some chronic diseases. Here, we established a competitive assay format to comprehensively quantify AGEs which bound to RAGE.

Microplate-based Assay for Screening of Advanced Glycation End Products Binding to Its Receptor.

Advanced Glycation End products (AGEs) are a group of amino-acid modifications produced with sugars or di-carbonyls. Some AGEs are known to affect health through binding to the receptor of AGEs (RAGE). Here, we propose a method for screening RAGE-binding AGEs by a competitive assay using purified RAGE and AGEs-specific antibody.

Co-expression of BirA with biotin bait achieves in vivo biotinylation of overexpressed stable N-glycosylated sRAGE in transgenic silkworms.

Here, we demonstrated the expression of the N-glycosylated extracellular ligand binding domain of receptor for advanced glycation end products (sRAGE) in middle silk glands (MSGs) of transgenic silkworms using the GAL4/UAS system. Over 1 mg of sRAGE was obtained from one transgenic silkworm. sRAGE purified from the silkworm exhibited good stability and maintained specific ligand-binding ability.

Screening, expression, and characterization of an anti-human oxidized low-density lipoprotein single-chain variable fragment.

Increased levels of oxidized low-density lipoprotein (OxLDL) in the blood circulation are correlated with atherosclerosis. Monoclonal antibody-based detection systems have been reported for OxLDL. We identified novel single-chain variable fragments (scFvs) having affinity for human OxLDL and related ligands.

Identification of C1q as a Binding Protein for Advanced Glycation End Products.

Advanced glycation end products (AGEs) make up a heterogeneous group of molecules formed from the nonenzymatic reaction of reducing sugars with the free amino groups of proteins. The abundance of AGEs in a variety of age-related diseases, including diabetic complications and atherosclerosis, and their pathophysiological effects suggest the existence of innate defense mechanisms. Here we examined the presence of serum proteins that are capable of binding glycated bovine serum albumin (AGEs-BSA), prepared upon incubation of BSA with dehydroascorbate, and identified complement component C1q subcomponent subunit A as a novel AGE-binding protein in human serum.

Fucoxanthin Derivatives: Synthesis and their Chemical Properties.

Novel fucoxanthin derivatives that could change the size of mixed micelles were synthesized. The mixed micelles under consideration consist of a bile acid and some additives. To change the affinity against a bile acid, we designed the synthesis of a fucoxanthin-lithocholic acid complex.

Lectin-like oxidized LDL receptor-1 is palmitoylated and internalizes ligands via caveolae/raft-dependent endocytosis.

Lectin-like oxidized low-density lipoprotein (LDL) receptor-1 (LOX-1) is an endothelial scavenger receptor that is important for oxidized low-density lipoprotein uptake. LOX-1 functions as an oligomer; however, little is known about the oligomeric complex and ligand processing after recognition by LOX-1. Here, we found that LOX-1 recognized and internalized ligands through the caveolae/raft-dependent endocytosis pathway in human coronary artery endothelial cells.

Identification of 4-hydroxy-2-nonenal-histidine adducts that serve as ligands for human lectin-like oxidized LDL receptor-1.

LOX-1 (lectin-like oxidized low-density lipoprotein receptor-1) is an endothelial scavenger receptor that is important for the uptake of OxLDL (oxidized low-density lipoprotein) and contributes to the pathogenesis of atherosclerosis. However, the precise structural motifs of OxLDL that are recognized by LOX-1 are unknown. In the present study, we have identified products of lipid peroxidation of OxLDL that serve as ligands for LOX-1.

Lipid peroxidation modification of protein generates Nepsilon-(4-oxononanoyl)lysine as a pro-inflammatory ligand.

4-Oxo-2(E)-nonenal (ONE), a peroxidation product of ω-6 polyunsaturated fatty acids, covalently reacts with lysine residues to generate a 4-ketoamide-type ONE-lysine adduct, N(ε)-(4-oxononanoyl)lysine (ONL). Using an ONL-coupled protein as the immunogen, we raised the monoclonal antibody (mAb) 9K3 directed to the ONL and conclusively demonstrated that the ONL was produced during the oxidative modification of a low density lipoprotein (LDL) in vitro. In addition, we observed that the ONL was present in atherosclerotic lesions, in which an intense immunoreactivity was mainly localized in the vascular endothelial cells and macrophage- and vascular smooth muscle cell-derived foam cells.

Lipid peroxidation generates body odor component trans-2-nonenal covalently bound to protein in vivo.

trans-2-Nonenal is an unsaturated aldehyde with an unpleasant greasy and grassy odor endogenously generated during the peroxidation of polyunsaturated fatty acids. 2-Nonenal covalently modified human serum albumin through a reaction in which the aldehyde preferentially reacted with the lysine residues. Modified proteins were immunogenic, and a specific monoclonal antibody (mAb) 27Q4 that cross-reacted with the protein covalently modified with 2-nonenal was raised from mouse.

Silicone-urethane adhesive for improved coverslip mounting and leak-free preparation of living cell observation chambers.

Using a combination of silicone and urethane resin, we established a rapid technique for preparing living specimens for microscopy. One major advantage of this technique is that the coverslip is rigidly attached and does not detach during handling. As a result, it is possible to continuously observe living cells at high magnification and resolution using an oil immersion objective.

Oxidized LDL receptor LOX-1 binds to C-reactive protein and mediates its vascular effects.

Background: C-reactive protein (CRP) exerts biological activity on vascular endothelial cells. This activity may promote atherothrombosis, but the effects of this activity are still controversial. Lectin-like oxidized LDL receptor-1 (LOX-1), the oxidized LDL receptor on endothelial cells, is involved in endothelial dysfunction induced by oxidized LDL.

Expression and characterization of recombinant C-terminal biotinylated extracellular domain of human receptor for advanced glycation end products (hsRAGE) in Escherichia coli.

The receptor for advanced glycation end products (RAGE) is a multi-ligand receptor involved in the development of diabetic complications. Using an Escherichia coli expression system, we have successfully expressed and purified the C-terminal biotinylated extracellular domain of human RAGE (hsRAGE), which consists of three immunoglobulin-like domains carrying three putative disulfide bonds. Over 90% of hsRAGE was expressed in soluble form in trxB and gor mutant E.

Lectin-like oxidized low-density lipoprotein receptor (LOX-1) functions as an oligomer and oligomerization is dependent on receptor density.

Lectin-like oxidized low-density lipoprotein (LDL) receptor (LOX-1) exists as a homodimer formed by an intermolecular disulfide bond. Although the dimer is the minimum structural unit of LOX-1 on cell membranes, LOX-1 can form larger noncovalent oligomeric complexes. But, the functional unit of LOX-1 is not known.

In vitro system for high-throughput screening of random peptide libraries for antimicrobial peptides that recognize bacterial membranes.

Antibacterial peptides have been isolated from a wide range of species. Some of these peptides act on microbial membranes, disrupting their barrier function. With the increasing development of antibiotic resistance by bacteria, these antibacterial peptides, which have a new mode of action, have attracted interest as antibacterial agents.

Purification, crystallization and preliminary X-ray analysis of the ligand-binding domain of human lectin-like oxidized low-density lipoprotein receptor 1 (LOX-1).

Two different fragments of the ligand-binding domain of LOX-1, the major receptor for oxidized low-density lipoprotein (LDL) on endothelial cells, have been crystallized in different forms. One crystal form contains the disulfide-linked dimer, which is the form of the molecule present on the cell surface; the other contains a monomeric form of the receptor that lacks the cysteine residue necessary to form disulfide-linked homodimers. The crystal of the monomeric ligand-binding domain belongs to space group P2(1)2(1)2(1), with unit-cell parameters a = 56.

Crystal structure of human lectin-like, oxidized low-density lipoprotein receptor 1 ligand binding domain and its ligand recognition mode to OxLDL.

Lectin-like, oxidized low-density lipoprotein (LDL) receptor 1, LOX-1, is the major receptor for oxidized LDL (OxLDL) in endothelial cells. We have determined the crystal structure of the ligand binding domain of LOX-1, with a short stalk region connecting the domain to the membrane-spanning region, as a homodimer linked by an interchain disulfide bond. In vivo assays with LOX-1 mutants revealed that the "basic spine," consisting of linearly aligned arginine residues spanning over the dimer surface, is responsible for ligand binding.

Human lectin-like oxidized low-density lipoprotein receptor-1 functions as a dimer in living cells.

Lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1) is a unique scavenger receptor that plays important roles in atherogenesis and has been thought to function as a monomer. Using coimmunoprecipitation studies, we demonstrate that human LOX-1 (hLOX-1) forms constitutive homo-interactions in vivo. Western blot analysis of cell lysates under nonreducing or reducing conditions revealed one clear immunoreactive species corresponding to the size of a putative receptor dimer or a monomer, respectively, consistent with the presence of disulfide-linked hLOX-1 complexes.

Refolding and characterization of the functional ligand-binding domain of human lectin-like oxidized LDL receptor.

Lectin-like oxidized low-density lipoprotein receptor (LOX-1), a type II membrane protein that can recognize a variety of structurally unrelated macromolecules, plays an important role in host defense and is implicated in atherogenesis. To understand the interaction between human LOX-1 and its ligands, in this study the functional C-type lectin-like domain (CTLD) of LOX-1 was reconstituted at high efficiency from inactive aggregates in Escherichia coli using a refolding technique based on an artificial chaperone. The CD spectra of the purified domain suggested that the domain has alpha-helical structure and the blue shift of Trp residues was observed on refolding of the domain.