Entero virus 71 (EV71) causes hand, foot, and mouth disease (HFMD) and occasionally leads to severe neurological complications and even death. Scavenger receptor class B member 2 (SCARB2) is a functional receptor for EV71, that mediates viral attachment, internalization, and uncoating. However, the exact binding site of EV71 on SCARB2 is unknown. In this study, we generated a monoclonal antibody (mAb) that binds to human but not mouse SCARB2. It is named JL2, and it can effectively inhibit EV71 infection of target cells. Using a set of chimeras of human and mouse SCARB2, we identified that the region containing residues 77-113 of human SCARB2 contributes significantly to JL2 binding. The structure of the SCARB2-JL2 complex revealed that JL2 binds to the apical region of SCARB2 involving α-helices 2, 5, and 14. Our results provide new insights into the potential binding sites for EV71 on SCARB2 and the molecular mechanism of EV71 entry.
Amino Acid Sequence ; Animals ; Antibodies, Monoclonal ; chemistry ; genetics ; metabolism ; Binding Sites ; Cell Line ; Crystallography, X-Ray ; Enterovirus A, Human ; drug effects ; genetics ; growth & development ; immunology ; Fibroblasts ; drug effects ; virology ; Gene Expression ; HEK293 Cells ; Humans ; Immunoglobulin Fab Fragments ; chemistry ; genetics ; metabolism ; Lysosome-Associated Membrane Glycoproteins ; chemistry ; genetics ; immunology ; Mice ; Models, Molecular ; Protein Binding ; Protein Conformation, alpha-Helical ; Protein Conformation, beta-Strand ; Protein Interaction Domains and Motifs ; Receptors, Scavenger ; chemistry ; genetics ; immunology ; Receptors, Virus ; chemistry ; genetics ; immunology ; Recombinant Fusion Proteins ; chemistry ; genetics ; immunology ; Sequence Alignment ; Sequence Homology, Amino Acid ; Sf9 Cells ; Spodoptera ; Thermodynamics

Changes in microparticles (MP) from red blood cell (RBC) concentrates in the context of irradiation have not been investigated. The aim of this study was to evaluate how irradiation affects the number of MPs within transfusion components. Twenty RBC concentrates, within 14 days after donation, were exposed to gamma rays (dose rate: 25 cGy) from a cesium-137 irradiator. Flow cytometry was used to determine the numbers of MPs derived from RBC concentrates before and 24 hr after irradiation. The mean number of MPs (±standard deviation) in RBC concentrates was 21.9×10(9)/L (±22.7×10(9)/L), and the total number of MPs ranged from 2.6×10(9)/L to 96.9×10(9)/L. The mean number of MPs increased to 22.6×10(9)/L (±31.6×10(9)/L) after irradiation. Before irradiation, the CD41-positive and CD235a-positive MPs constituted 9.5% (1.0×10(9)/L) and 2.2% (263×10(6)/L) of total MPs, respectively. After irradiation, CD41-positive MPs increased to 12.1% (1.5×10(9)/L) (P=0.014), but the CD235a-positive MPs decreased to 2.0% (214×10(6)/L) of the total MPs (P=0.369). Irradiation increases the number of CD41-positive MPs within RBC concentrates, suggesting the irradiation of RBC concentrates could be associated with thrombotic risk of circulating blood through the numerical change.
Cell-Derived Microparticles/chemistry/*metabolism/radiation effects ; Erythrocytes/*cytology/radiation effects ; Flow Cytometry ; Gamma Rays ; Humans ; Membrane Glycoproteins/metabolism ; Metalloendopeptidases/metabolism ; Platelet Membrane Glycoprotein IIb/metabolism

The present study was designed to target fish for potential bioactive components contained in a Huang Lian Jie Du decoction (HLJDD) and identify the underlying mechanisms of action for the treatment of sepsis at the molecular level. he bioactive components database of HLJDD was constructed and the sepsis-associated targets were comprehensively investigated. The 3D structures of the PAFR and TXA2R proteins were established using the homology modelling (HM) method, and the molecular effects for sepsis treatment were analysed by comparing the bioactive components database and the sepsis targets using computational biology methods. The results of the screening were validated with biological testing against the human oral epidermal carcinoma cell line KB in vitro. We found that multiple bioactive compounds contained in the HLJDD interacted with multiple targets. We also predicted the promising compound leads for sepsis treatment, and the first 28 compounds were characterized. Several compounds, such as berberine, berberrubine and epiberberine, dose-dependently inhibited PGE2 production in human KB cells, and the effects were similar in the presence or absence of TPA. This study demonstrates a novel approach to identifying natural chemical compounds as new leads for the treatment of sepsis.
Anti-Inflammatory Agents, Non-Steroidal ; pharmacokinetics ; Berberine ; analogs & derivatives ; pharmacokinetics ; Dinoprostone ; biosynthesis ; Drugs, Chinese Herbal ; chemistry ; pharmacokinetics ; Humans ; KB Cells ; Platelet Membrane Glycoproteins ; drug effects ; Protein Transport ; Receptors, G-Protein-Coupled ; drug effects ; Receptors, Thromboxane A2, Prostaglandin H2 ; drug effects ; Sepsis ; drug therapy ; metabolism ; Tetradecanoylphorbol Acetate ; pharmacokinetics

Uch37 is a de-ubiquitinating enzyme that is activated by Rpn13 and involved in the proteasomal degradation of proteins. The full-length Uch37 was shown to exhibit low iso-peptidase activity and is thought to be auto-inhibited. Structural comparisons revealed that within a homo-dimer of Uch37, each of the catalytic domains was blocking the other's ubiquitin (Ub)-binding site. This blockage likely prevented Ub from entering the active site of Uch37 and might form the basis of auto-inhibition. To understand the mode of auto-inhibition clearly and shed light on the activation mechanism of Uch37 by Rpn13, we investigated the Uch37-Rpn13 complex using a combination of mutagenesis, biochemical, NMR, and small-angle X-ray scattering (SAXS) techniques. Our results also proved that Uch37 oligomerized in solution and had very low activity against the fluorogenic substrate ubiquitin-7-amino-4-methylcoumarin (Ub-AMC) of de-ubiquitinating enzymes. Uch37Δ(Hb,Hc,KEKE), a truncation removal of the C-terminal extension region (residues 256-329) converted oligomeric Uch37 into a monomeric form that exhibited iso-peptidase activity comparable to that of a truncation-containing the Uch37 catalytic domain only. We also demonstrated that Rpn13C (Rpn13 residues 270-407) could disrupt the oligomerization of Uch37 by sequestering Uch37 and forming a Uch37-Rpn13 complex. Uch37 was activated in such a complex, exhibiting 12-fold-higher activity than Uch37 alone. Time-resolved SAXS (TR-SAXS) and FRET experiments supported the proposed mode of auto-inhibition and the activation mechanism of Uch37 by Rpn13. Rpn13 activated Uch37 by forming a 1:1 stoichiometric complex in which the active site of Uch37 was accessible to Ub.
Binding Sites ; Catalytic Domain ; Chromatography, Gel ; Crystallography, X-Ray ; Humans ; Membrane Glycoproteins ; chemistry ; genetics ; metabolism ; Nuclear Magnetic Resonance, Biomolecular ; Protein Binding ; Protein Conformation ; Protein Multimerization ; Scattering, Small Angle ; Ubiquitin Thiolesterase ; chemistry ; genetics ; metabolism ; Ultracentrifugation

Unlike the well-established picture for the entry of enveloped viruses, the mechanism of cellular entry of non-enveloped eukaryotic viruses remains largely mysterious. Picornaviruses are representative models for such viruses, and initiate this entry process by their functional receptors. Here we present the structural and functional studies of SCARB2, a functional receptor of the important human enterovirus 71 (EV71). SCARB2 is responsible for attachment as well as uncoating of EV71. Differences in the structures of SCARB2 under neutral and acidic conditions reveal that SCARB2 undergoes a pivotal pH-dependent conformational change which opens a lipid-transfer tunnel to mediate the expulsion of a hydrophobic pocket factor from the virion, a pre-requisite for uncoating. We have also identified the key residues essential for attachment to SCARB2, identifying the canyon region of EV71 as mediating the receptor interaction. Together these results provide a clear understanding of cellular attachment and initiation of uncoating for enteroviruses.
Acids ; chemistry ; Amino Acid Sequence ; Animals ; Capsid Proteins ; chemistry ; genetics ; metabolism ; Enterovirus A, Human ; genetics ; metabolism ; physiology ; HEK293 Cells ; Host-Pathogen Interactions ; Humans ; Hydrogen-Ion Concentration ; Lysosome-Associated Membrane Glycoproteins ; chemistry ; genetics ; metabolism ; Molecular Docking Simulation ; Molecular Sequence Data ; Protein Binding ; Protein Conformation ; Protein Interaction Mapping ; Protein Structure, Tertiary ; RNA, Viral ; genetics ; metabolism ; Receptors, Scavenger ; chemistry ; genetics ; metabolism ; Sequence Homology, Amino Acid ; Sf9 Cells ; Static Electricity ; Virion ; genetics ; metabolism ; Virus Attachment

Chronic granulomatous disease (CGD) is a rare genetic disease, which is caused by defects in the NADPH oxidase complex (gp91phox, p22phox, p40phox, p47phox, and p67phox) of phagocytes. This defect results in impaired production of superoxide anions and other reactive oxygen species (ROS), which are necessary for killing bacterial and fungal microorganisms and leads to recurrent, life-threatening bacterial and fungal infections and granulomatous inflammation. The dihydrorhodamine (DHR) flow cytometry assay is a useful diagnostic tool for CGD that can detect absent or reduced NADPH oxidase activity in stimulated phagocytes. We report a patient with X-linked CGD carrying a novel mutation of the CYBB gene whose chimerism status following hematopoietic stem cell transplantation (HSCT) has been rapidly determined using the DHR assay. The level of DHR activity correlates well with short tandem repeat PCR analysis. Considering the advantages of this simple, rapid, and cost-effective procedure, serial measurement of DHR assay would facilitate the rapid determination of a patient's engraftment status, as a supplementary monitoring tool of chimerism status following HSCT.
Base Sequence ; *Chimerism ; DNA Mutational Analysis ; Flow Cytometry ; Granulomatous Disease, Chronic/*diagnosis/*enzymology/genetics/surgery ; *Hematopoietic Stem Cell Transplantation ; Homozygote ; Humans ; Infant, Newborn ; Male ; Membrane Glycoproteins/chemistry/*genetics ; Mutation ; NADPH Oxidase/chemistry/*genetics ; Polymerase Chain Reaction ; Rhodamines/chemistry/metabolism

Leukocyte immunoglobulin-like receptors (LILRs), also called CD85s, ILTs, or LIRs, are important mediators of immune activation and tolerance that contain tandem immunoglobulin (Ig)-like folds. There are 11 (in addition to two pseudogenes) LILRs in total, two with two Ig-like domains (D1D2) and the remaining nine with four Ig-like domains (D1D2D3D4). Thus far, the structural features of the D1D2 domains of LILR proteins are well defined, but no structures for the D3D4 domains have been reported. This is a very important field to be studied as it relates to the unknown functions of the D3D4 domains, as well as their relative orientation to the D1D2 domains on the cell surface. Here, we report the crystal structures of the D3D4 domains of both LILRB1 and LILRB2. The two Ig-like domains of both LILRB1-D3D4 and LILRB2-D3D4 are arranged at an acute angle (∼60°) to form a bent structure, resembling the structures of natural killer inhibitory receptors. Based on these two D3D4 domain structures and previously reported D1D2/HLA I complex structures, two alternative models of full-length (four Ig-like domains) LILR molecules bound to HLA I are proposed.
Amino Acid Sequence ; Antigens, CD ; chemistry ; Crystallography, X-Ray ; Histocompatibility Antigens Class I ; chemistry ; Humans ; Immunoglobulins ; chemistry ; Leukocyte Immunoglobulin-like Receptor B1 ; Membrane Glycoproteins ; chemistry ; Models, Molecular ; Peptides ; chemistry ; metabolism ; Protein Binding ; Protein Structure, Tertiary ; Receptors, Immunologic ; chemistry ; Signal Transduction

OBJECTIVETo investigate the levels of lipopolysaccharide binding protein (LBP) in serum and ascites of cirrhotic patients, and determine their diagnostic value for spontaneous bacterial peritonitis (SBP).

METHODSCirrhotic patients were divided into groups according to diagnosis of SBP, ascites without SBP, no ascites. To explore the significance of LBP in clinically suspect SBP cases, the ascites without SBP group was sub-divided into two groups according to the symptoms of abdominal pain or elevated white blood cell (WBC) count, and abdominal pain combined with elevated WBC count. Two control groups were composed of patients with intraperitoneal pus and a group of healthy, non-cirrhotic individuals. The LBP levels in serum and ascites were determined by enzyme-linked immunosorbent assay (ELISA). The ascites routine, ascites culture and albumin assay were carried out in the Second Affiliated Hospital of Chongqing Medical University. Data between the two groups were compared using the t-test or nonparametric test of independent samples, and the areas under the curve were compared using the Z test. Results The levels of LBP in serum and pus were significantly higher in the intraperitoneal pus group than in the cirrhosis group with ascites (P less than 0.01).

RESULTSThe level of serum LBP was significantly higher in the cirrhosis group with SBP than in the cirrhosis group without SBP but with ascites and the cirrhosis group with no ascites (P less than 0.01). There was no significant difference in the level of ascites LBP in the cirrhosis group with SBP and the cirrhosis group without SBP but with ascites (P more than 0.05). In the clinically suspect cases with SBP, the levels of LBP in serum and ascites were significantly higher than those in the cirrhosis group without SBP but with ascites (228.00 mug/ml vs. 80.95 mug/ml and 22.50 mug/ml vs. 11.45 mug/ml, P less than 0.05). Determination of serum LBP had a higher sensitivity than the determination of ascites LBP or ascites WBC.

CONCLUSIONGram-negative bacteria infection in the intra-abdominal cavity causes serum and body fluid levels of LBP to increase significantly. Patients with cirrhosis complicated with SBP have significantly elevated levels of serum LBP. The serum and ascites LBP levels are significantly elevated in SBP patients with suspected clinical diagnosis. Measurements of both the serum LBP and ascites LBP may have diagnostic value for SBP.

Acute-Phase Proteins ; metabolism ; Adult ; Aged ; Ascites ; diagnosis ; microbiology ; Ascitic Fluid ; chemistry ; Bacterial Infections ; complications ; diagnosis ; Carrier Proteins ; blood ; metabolism ; Case-Control Studies ; Female ; Humans ; Liver Cirrhosis ; complications ; microbiology ; Male ; Membrane Glycoproteins ; blood ; metabolism ; Middle Aged ; Peritonitis ; complications ; diagnosis ; microbiology

The primary determinant of influenza virus infectivity is the type of linkage between sialic acid and oligosaccharides on the host cells. Hemagglutinin of avian influenza viruses preferentially binds to sialic acids linked to galactose by an alpha-2,3 linkage whereas hemagglutinin of human influenza viruses binds to sialic acids with an alpha-2,6 linkage. The distribution patterns of influenza receptors in the avian respiratory tracts are of particular interest because these are important for initial viral attachment, replication, and transmission to other species. In this study, we examined the distribution patterns of influenza receptors in the respiratory tract of chickens, ducks, pheasants, and quails because these species have been known to act as intermediate hosts in interspecies transmission. Lectin histochemistry was performed to detect receptor-bearing cells. Cell-specific distribution of the receptors was determined and expression densities were compared. We observed species-, site-, and cell-specific variations in receptor expression. In general, receptor expression was the highest in quails and lowest in ducks. Pheasants and quails had abundant expression of both types of receptors throughout the respiratory tract. These results indicate that pheasants and quails may play important roles as intermediate hosts for the generation of influenza viruses with pandemic potential.
Animals ; Cell Membrane/metabolism/virology ; Hemagglutinin Glycoproteins, Influenza Virus/metabolism ; Host-Pathogen Interactions ; Influenza A virus/*metabolism ; Influenza in Birds/metabolism/transmission ; Lectins/metabolism ; Poultry/metabolism/*virology ; Poultry Diseases/metabolism ; Receptors, Cell Surface/analysis/chemistry/metabolism ; Receptors, Virus/*analysis/metabolism ; Respiratory System/*chemistry ; Sialic Acids/metabolism ; Species Specificity ; Specific Pathogen-Free Organisms

OBJECTIVETo observe the effects of a biotic elicitor fungal hyphae extract, an abiotic elicitor methyl jasmonate and their synergistic action on the accumulation of phenolic acids and tanshinones in Salvia miltiorrhiza hairy root.

METHODDifferent elicitors were added to S. miltiorrhiza hairy root, which was subcultured for 21 days, the dry weight and contents of phenolic acids and tanshinones were determined at different harvest-time.

RESULTS. miltiorrhiza hairy root growth was significantly inhibited by all three treatments and the accumulation of cryptotanshinone and dihydrotanshinone were promoted by each elicition. As for the accumulation of phenolic acids, there were differences between fungal elicitor and methyl jasmonate treatments, they were promoted by methyl jasmonate while inhibited in a certain extent by fungal hyphae extract.

CONCLUSIONFungal elicitor, methyl jasmonate and their synergistic action have significant influence on accumulation of components in S. miltiorrhiza hairy root, and the effect varies between phenolic acids and tanshinones. There is no correlation between production of water-soluble ingredients and fat-soluble components on the whole under three different treatments.

Acetates ; pharmacology ; Cyclopentanes ; pharmacology ; Diterpenes, Abietane ; metabolism ; Fungal Proteins ; metabolism ; pharmacology ; Hydroxybenzoates ; metabolism ; Membrane Glycoproteins ; metabolism ; pharmacology ; Oxylipins ; pharmacology ; Phytophthora ; chemistry ; metabolism ; Plant Extracts ; metabolism ; Plant Roots ; drug effects ; growth & development ; metabolism ; microbiology ; Salvia miltiorrhiza ; drug effects ; growth & development ; metabolism ; microbiology