Protein -pyrrolation, which converts lysine residues to -pyrrole-l-lysine (pyrK), is a naturally occurring covalent modification. The pyrrolated proteins have a unique property of binding to DNA-staining agents, such as SYBR Green I (SG), and anti-DNA antibodies, suggesting a physiologically relevant modification that gives rise to DNA mimic protein. These properties of pyrrolated protein are suggested to be associated with innate and autoimmune responses.
View Article and Find Full Text PDFLysine N-pyrrolation, a posttranslational modification, which converts lysine residues to N-pyrrole-L-lysine, imparts electronegative properties to proteins, causing them to mimic DNA. Apolipoprotein E (apoE) has been identified as a soluble receptor for pyrrolated proteins (pyrP), and accelerated lysine N-pyrrolation has been observed in apoE-deficient (apoE) hyperlipidemic mice. However, the impact of pyrP accumulation consequent to apoE deficiency on the innate immune response remains unclear.
View Article and Find Full Text PDFActivation of corticotropin-releasing factor receptor 2β (CRFR2β) results in increased skeletal muscle mass and the prevention of muscle atrophy. Using a luciferase reporter assay, we screened 357 functional food factors that activate CRFR2β and, subsequently, confirmed that nobiletin (NBT) increases CRFR2β activity. Additionally, we found that NBT augments the activity of the endogenous peptide ligand urocortin 2 (Ucn2) in a concentration-dependent manner.
View Article and Find Full Text PDFLysine -pyrrolation converts lysine residues to -pyrrole-l-lysine (pyrK) in a covalent modification reaction that significantly affects the chemical properties of proteins, causing them to mimic DNA. pyrK in proteins has been detected , indicating that pyrrolation occurs as an endogenous reaction. However, the source of pyrK remains unknown.
View Article and Find Full Text PDFBiochem Biophys Res Commun
January 2020
Muscle myogenesis is an essential step for muscle development and recovery. During muscle fusion, multiple molecules are thought to be necessary for the formation of normal myotubes. Milk fat globule-EGF factor 8 (MFG-E8) and Gas6 are phosphatidylserine-recognizing bridging molecules that are secreted mainly from immune cells.
View Article and Find Full Text PDFLysine -pyrrolation, converting lysine residues to -pyrrole-l-lysine, is a recently discovered post-translational modification. This naturally occurring reaction confers electrochemical properties onto proteins that potentially produce an electrical mimic to DNA and result in specificity toward DNA-binding molecules such as anti-DNA autoantibodies. The discovery of this unique covalent protein modification provides a rationale for establishing the molecular mechanism and broad functional significance of the formation and regulation of -pyrrole-l-lysine-containing proteins.
View Article and Find Full Text PDFBackground: Xp11.2 translocation renal cell carcinoma (RCC) is a rare variety of a kidney neoplasm. We report a case of bilateral Xp11.
View Article and Find Full Text PDFScope: Modulating β -adrenergic receptor (β -AR) expression and activation is important for maintaining skeletal muscle function. In this study, two food factors, resveratrol (RSV) and genistein (GEN), that are able to regulate β -AR promoter activity and may improve skeletal muscle function are identified.
Methods And Results: Using luciferase reporter assay, 357 functional food factors as candidates for β -AR promoter activity have been screened and subsequently RSV and GEN increase β -AR promoter activity and β -AR mRNA expression.
J Nutr Sci Vitaminol (Tokyo)
October 2018
Maintaining skeletal muscle functions by controlling muscle metabolism is of utmost importance. β-Adrenergic receptor (β-AR), which is expressed in skeletal muscle, is a member of the G-protein-coupled receptor family that plays a critical role in the maintenance of muscle mass. In the present study, using luciferase reporter assays in β-AR-expressing HEK293 cells, we discovered several food factors that exhibited agonistic activity at mouse or human β-AR.
View Article and Find Full Text PDF(-)-Epigallocatechin-3-O-gallate (EGCG), the most abundant polyphenol in green tea, mediates the oxidative modification of proteins, generating protein carbonyls. However, the underlying molecular mechanism remains unclear. Here we analyzed the EGCG-derived intermediates generated upon incubation with the human serum albumin (HSA) and established that EGCG selectively oxidized the lysine residues via its oxidative deamination activity.
View Article and Find Full Text PDFAdvanced 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.
View Article and Find Full Text PDFBackground: Milk fat globule epidermal growth factor 8 (MFG-E8) is a protein that binds to apoptotic cells by recognizing phosphatidylserine and enhances the engulfment of apoptotic cells by macrophages. Many apoptotic cells are left unengulfed in the germinal centers of the spleen in the MFG-E8-deficient (MFG-E8(-/-)) mice, and these mice develop an autoimmune disease.
Results: We found that the MFG-E8 deficiency was accompanied by the increased production of immunoglobulins.
Cyclooxygenase-2 (Cox-2) is rapidly expressed by various stimuli and plays a key role in conversion of free arachidonic acid to prostaglandins. We have previously identified 4-hydroxy-2-nonenal (HNE), a lipid peroxidation-derived electrophile, as the potent Cox-2 inducer in rat epithelial RL34 cells and revealed that the HNE-induced Cox-2 expression resulted from the stabilization of Cox-2 mRNA that is mediated by the p38 mitogen-activated protein kinase signaling pathway. In the present study, we investigated an alternative regulatory mechanism of Cox-2 expression mediated by a transcription factor p53.
View Article and Find Full Text PDFCovalent modification of proteins exerts significant effects on their chemical properties and has important functional and regulatory consequences. We now report the identification and verification of an electrically-active form of modified proteins recognized by a group of small molecules commonly used to interact with DNA. This previously unreported property of proteins was initially discovered when the γ-ketoaldehydes were identified as a source of the proteins stained by the DNA intercalators.
View Article and Find Full Text PDFMilk fat globule epidermal growth factor 8 (MFG-E8) is a protein that binds to apoptotic cells by recognizing phosphatidylserine and enhances the engulfment of apoptotic cells by macrophages. Many apoptotic cells are left unengulfed in the germinal centers of the spleen in the MFG-E8-deficient (MFG-E8(-/-)) mice, and these mice develop an autoimmune disease resembling human systemic lupus erythematosus. We found that the MFG-E8 deficiency was accompanied by the increased production of immunoglobulins.
View Article and Find Full Text PDFBackground: Advanced glycation end products (AGEs) can act as neoantigens to trigger immune responses.
Results: Natural IgM antibodies against AGEs recognize multiple molecules, including DNA and chemically modified proteins.
Conclusion: There is a close relationship between the formation of AGEs and innate immune responses.
Acrolein shows a facile reactivity with the ε-amino group of lysine to form N(ε)-(3-formyl-3,4-dehydropiperidino)lysine (FDP-lysine) as the major product. In addition, FDP-lysine generated in the acrolein-modified protein could function as an electrophile, reacting with thiol compounds, to form an irreversible thioether adduct. In the present study, to establish the utility of this irreversible conjugate, we attempted to use it as an immunogen to raise a monoclonal antibody (mAb), which specifically recognized protein-bound thiol compounds.
View Article and Find Full Text PDFAcrolein, a ubiquitous pollutant in the environment, is endogenously formed through oxidation reactions and is believed to be involved in cytopathological effects observed during oxidative stress. Acrolein exerts these effects because of its facile reactivity with biological materials, particularly proteins. In the present study, we quantitatively analyzed the acrolein-specific adducts generated during lipid peroxidation-modification of proteins and identified the acrolein adduct most abundantly generated in the in vitro oxidized low-density lipoproteins (LDL).
View Article and Find Full Text PDFLipid peroxidation in tissue and in tissue fractions represents a degradative process, which is the consequence of the production and the propagation of free radical reactions primarily involving membrane polyunsaturated fatty acids, and has been implicated in the pathogenesis of numerous diseases, including systemic lupus erythematosus (SLE). We have found that bovine serum albumin incubated with peroxidized polyunsaturated fatty acids significantly cross-reacted with the sera from MRL-lpr mice, a representative murine model of SLE. To identify the active substances responsible for the generation of autoantigenic epitopes recognized by the SLE sera, we performed the activity-guiding separation of a principal source from 13-hydroperoxy-9Z,11E-octadecadienoic acid and identified 4-oxo-2-nonenal (ONE), a highly reactive aldehyde originating from the peroxidation of ω6 polyunsaturated fatty acids, as the source of the autoantigenic epitopes.
View Article and Find Full Text PDFObjective: This study was designed to determine the relative activity of angiogenesis-related genes in the regulation of tumorigenicity and subsequent metastases of urothelial cell carcinomas (UC) of the urinary bladder.
Methods: We selected the clones with the highest and lowest expression level of basic fibroblast growth factor (bFGF), vascular endothelial growth factor (VEGF)/vascular permeability factor or interleukin-8 (IL-8) in the highly tumorigenic and metastatic human UC cell line 253J B-V. Tumorigenicity and production of spontaneous lymph node metastases were evaluated 1, 2, 4, 8 and 12 weeks after orthotopic implantation of each specific expression clone into the urinary bladder of athymic nude mice.
Silica gel was used as core particles to design a simple preparation for controlled delivery system with a high drug content. Drug loading was carried out by immersing the silica gel in a pre-heated drug solution or suspension. HPLC, SEM, DSC, PXRD analysis and N2 adsorption studies evaluated the drug-loading process.
View Article and Find Full Text PDFWe report our clinical findings on 12 tumors (11 patients) successfully resected by partial nephrectomy with a microwave tissue coagulator (MTC) without renal pedicle clamping, including laparoscopic operation in 4 patients. All patients presented with a renal tumor detected incidentally by ultrasonography or computed tomography. The mean size of renal tumor was 1.
View Article and Find Full Text PDFJ Colloid Interface Sci
December 2003
A series of aluminum-containing kanemite (Al-kanemite) samples with several Si/Al molar ratios were synthesized. The Al-kanemite samples were pillared with silica. X-ray diffractograms showed that the layered structure of the Al-kanemite samples was maintained at Si/Al= infinity approximately 10 but was broken at Si/Al = 5, 2.
View Article and Find Full Text PDFThe aim of this study is to investigate the effect of geometric structure and surface wettability of glidant on tablet hardness. Geometric structure is defined, in this work, as three-dimensional structure such as porosity, particle size and specific surface area. A variety of silica was incorporated in direct compressive fillers as glidant and mixed powder was compressed in single punch tablet machine with and without 0.
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