OBJECTIVETo investigate whether leptin receptor Lys109Arg polymorphism influences non-alcoholic fatty liver disease.

METHODSGenomic DNA samples were extracted from blood of subjects who had received a physical examination. Genotyping was performed using oligonucleotide microarray and these fluorescence labeled PCR-amplified fragments were hybridized to allele-specific oligonucleotide probes. The relevant mutation was confirmed by sequencing analysis.

RESULTSA total of 180 subjects (109 males and 71 females) were included in the study, 117 of them had fatty liver disease and the other 63 had no liver problems and served as healthy controls. There were 144 (80%) subjects with GG genotype (Arg109Arg), 33 (18.3%) with GA genotype (Lys109Arg) and 3 (1.7%) with AA genotype (Lys109Lys). The distribution of leptin receptor Lys109Arg polymorphism had no significant difference (P > 0.05) between the fatty liver disease patients (95GG, 21GA and 1AA) and the healthy control subjects (49GG, 12GA and 2AA). The abdominal wall fat was significantly thicker in AA genotype subjects (4.1+/-0.4) cm than that in GA (2.8+/-0.6) cm and GG genotype subjects (2.7+/-0.7) cm (F = 5.197, P = 0.006). The serum cholesterol levels in AA genotype subjects (5.1+/-0.4) mmol/L was significantly lower than that in AG (25.5+/-6.9) mmol/L and GG genotype (27.2+/-8.4) mmol/L subjects (F = 8.164, P = 0.005). There were no significant differences in age, body mass index, hip circumference, waist circumference, blood pressure (BP), percentage of body fat, blood protein, triglyceride, HDL and fasting blood glucose between AA, GG and GA genotype subjects.

CONCLUSIONLeptin receptor Lys109Arg polymorphism may be involved in the regulation of distribution of abdominal wall fat thickness and cholesterol metabolism. Whether leptin receptor Lys109Arg polymorphism is in any way related to fatty liver disease is still not known.

Adult ; Arginine ; chemistry ; genetics ; Fatty Liver ; etiology ; genetics ; Female ; Genotype ; Humans ; Lysine ; chemistry ; genetics ; Male ; Middle Aged ; Polymorphism, Genetic ; genetics ; Receptors, Cell Surface ; genetics ; Receptors, Leptin

Toll-like receptor (TLR) 3 is a member of the TLR family that confers innate immunity by recognizing viral pathogens. Herein, we report that the TLR3 isoform is expressed on human primary cells and cell lines. This isoform has 2, 520 bp cDNAs compared to the 2, 712 bp of full cDNA, is produced by deletion of an intron-like sequence within exon 4 and is co-expressed with wild type TLR3 in primary human astrocytes and glioblastoma cell lines. This finding suggests the TLR3 isoform in astrocytes may have a different immunological role for binding ligands during the immune response in brain.
Astrocytes/*physiology ; Cloning, Molecular ; Human ; Isomerism ; Membrane Glycoproteins/chemistry/*genetics ; Receptors, Cell Surface/chemistry/*genetics ; Support, Non-U.S. Gov't

Analysis of the T-cell receptor (TCR) repertoire of innate CD4+ T cells selected by major histocompatibility complex (MHC) class II-dependent thymocyte-thymocyte (T-T) interaction (T-T CD4+ T cells) is essential for predicting the characteristics of the antigens that bind to these T cells and for distinguishing T-T CD4+ T cells from other types of innate T cells. Using the TCRmini Tg mouse model, we show that the repertoire of TCRalpha chains in T-T CD4+ T cells was extremely diverse, in contrast to the repertoires previously described for other types of innate T cells. The TCRalpha chain sequences significantly overlapped between T-T CD4+ T cells and conventional CD4+ T cells in the thymus and spleen. However, the diversity of the TCRalpha repertoire of T-T CD4+ T cells seemed to be restricted compared with that of conventional CD4+ T cells. Interestingly, the frequency of the parental OT-II TCRalpha chains was significantly reduced in the process of T-T interaction. This diverse and shifted repertoire in T-T CD4+ T cells has biological relevance in terms of defense against diverse pathogens and a possible regulatory role during peripheral T-T interaction.
Amino Acid Sequence ; Animals ; Antigens, Surface/metabolism ; CD4-Positive T-Lymphocytes/cytology/*immunology/*metabolism ; Cell Communication ; Cell Differentiation/genetics/immunology ; Clonal Evolution ; Histocompatibility Antigens Class II/*immunology ; *Immunity, Innate ; Immunophenotyping ; Lymphocyte Count ; Mice ; Mice, Knockout ; Mice, Transgenic ; Peptide Fragments/chemistry ; Phenotype ; Receptors, Antigen, T-Cell/chemistry/*genetics/metabolism ; Receptors, Antigen, T-Cell, alpha-beta/chemistry/genetics ; Spleen/cytology ; Thymocytes/cytology/immunology/metabolism

Avian influenza A virus continues to pose a global threat with occasional H5N1 human infections, which is emphasized by a recent severe human infection caused by avian-origin H7N9 in China. Luckily these viruses do not transmit efficiently in human populations. With a few amino acid substitutions of the hemagglutinin H5 protein in the laboratory, two H5 mutants have been shown to obtain an air-borne transmission in a mammalian ferret model. Here in this study one of the mutant H5 proteins developed by Kawaoka's group (VN1203mut) was expressed in a baculovirus system and its receptor-binding properties were assessed. We herein show that the VN1203mut had a dramatically reduced binding affinity for the avian α2,3-linkage receptor compared to wild type but showed no detectable increase in affinity for the human α2,6-linkage receptor, using Surface Plasmon Resonance techonology. Further, the crystal structures of the VN1203mut and its complexes with either human or avian receptors demonstrate that the VN1203mut binds the human receptor in the same binding manner (cis conformation) as seen for the HAs of previously reported 1957 and 1968 pandemic influenza viruses. Our receptor binding and crystallographic data shown here further confirm that the ability to bind the avian receptor has to decrease for a higher human receptor binding affinity. As the Q226L substitution is shown important for obtaining human receptor binding, we suspect that the newly emerged H7N9 binds human receptor as H7 has a Q226L substitution.
Air Microbiology ; Crystallography, X-Ray ; Glycosylation ; Hemagglutinin Glycoproteins, Influenza Virus ; chemistry ; genetics ; metabolism ; Humans ; Influenza A Virus, H5N1 Subtype ; chemistry ; metabolism ; Influenza A Virus, H7N9 Subtype ; chemistry ; Models, Molecular ; Mutant Proteins ; chemistry ; genetics ; metabolism ; Protein Binding ; Protein Stability ; Receptors, Cell Surface ; genetics ; metabolism ; Solubility ; Surface Plasmon Resonance ; Temperature

OBJECTIVEThis study examined the effect of high concentration of phenylalanine (Phe) on Nogo-66 receptor (NgR) expression in the cortical neurons of rats in vitro in order to investigate whether NgR is involved in the etiology of Phe-induced brain damage.

METHODSNeurons from the cerebral cortex of embryonic rats were cultured for 3 days and then were treated with 0.9 mM Phe. After 12, 24 and 48 hrs of Phe treatment, mRNA and protein expression of NgR was detected by real-time PCR and Western blot respectively. Growth cones and growth axons of neurons were detected by immunofluorescence and immunohistochemistry respectively after 12 and 24 hrs of Phe treatment.

RESULTSThe length of growth axons of neurons was significantly shorter after 12 and 24 hrs of Phe treatment compared with the control group without Phe treatment (P<0.05). Growth cones collapse occurred in 12.5+/-9.7% and 24.1+/-4.5% of neurons respectively after 12 and 24 hrs of Phe treatment but only in 3.5+/-1.5% in the control group (P<0.01). The protein level of NgR after 12, 24 and 48 hrs of Phe treatment was up-regulated, with 9.0, 9.4 and 12.6 times as the control. mRNA level of NgR in the Phe treatment group did not differ from control.

CONCLUSIONSHigh concentration of Phe can induce an increased NgR protein expression in cortical neurons, and the increased NgR expression may contribute to the growth cones collapse and the inhibitory activities of axon regeneration after injury.

Animals ; Blotting, Western ; Cerebral Cortex ; chemistry ; drug effects ; GPI-Linked Proteins ; Immunohistochemistry ; Myelin Proteins ; analysis ; genetics ; Nogo Receptor 1 ; Phenylalanine ; pharmacology ; Polymerase Chain Reaction ; RNA, Messenger ; analysis ; Rats ; Rats, Sprague-Dawley ; Receptors, Cell Surface ; analysis ; genetics

Staphylococcus aureus is the most important Gram-positive colonizer of human skin and nasal passage, causing high morbidity and mortality. SD-repeat containing protein D (SdrD), an MSCRAMM (Microbial Surface Components Recognizing Adhesive Matrix Molecules) family surface protein, plays an important role in S. aureus adhesion and pathogenesis, while its binding target and molecular mechanism remain largely unknown. Here we solved the crystal structures of SdrD N2-N3 domain and N2-N3-B1 domain. Through structural analysis and comparisons, we characterized the ligand binding site of SdrD, and proposed a featured sequence motif of its potential ligands. In addition, the structures revealed for the first time the interactions between B1 domain and N2-N3 domain among B domain-containing MSCRAMMs. Our results may help in understanding the roles SdrD plays in S. aureus adhesion and shed light on the development of novel antibiotics.
Amino Acid Sequence ; Bacterial Proteins ; chemistry ; genetics ; metabolism ; Binding Sites ; Calcium ; chemistry ; metabolism ; Calcium-Binding Proteins ; chemistry ; genetics ; metabolism ; Hydrogen Bonding ; Ligands ; Molecular Sequence Data ; Protein Binding ; Protein Structure, Tertiary ; Receptors, Cell Surface ; chemistry ; metabolism ; Recombinant Proteins ; biosynthesis ; chemistry ; genetics ; Sequence Alignment ; Staphylococcus aureus ; metabolism

The serine protease urokinase-type plasminogen activator (uPA) is implicated in pericellular proteolysis in a variety of physiological and pathological processes including angiogenesis and tumor metastasis. The kringle domain of uPA (UK1) has proven to be an anti-angiogenic molecule with unknown mechanism and amino terminal fragment of uPA (u-ATF) with additional growth factor-like domain can be used for blocking interaction of uPA and uPA receptor. Here, we compared anti-angiogenic activities of these two molecules in vitro and in vivo. The recombinant u-ATF from E. coli and refolded in vitro was found to bind to uPAR with high affinity, whereas E. coli-derived UK1 showed no binding by Biacore analysis. In contrast to UK1 having potent inhibitory effect, u-ATF exhibited low inhibitory effect on bovine capillary endothelial cell growth (ED(50)>320 nM). Furthermore, u-ATF inhibition of VEGF-induced migration of human umbilical vein endothelial cell was far less sensitive (IC(50)= 600 nM) than those observed with UK1, and angiogenesis inhibition was marginal in chorioallantoic membrane. These results suggest that kringle domain alone is sufficient for potent anti- angiogenic activity and additional growth factor-like domain diverts this molecule in undergoing different mechanism such as inhibition of uPA/uPAR interaction rather than undergoing distinct anti- angiogenic mechanism driven by kringle domain.
Animals ; Biosensing Techniques ; Cattle ; Cell Division/drug effects ; Cell Movement/*drug effects ; Cells, Cultured ; Chickens ; Cricetinae ; Endothelial Cells/*cytology/*drug effects ; Humans ; Kinetics ; *Kringles ; Ligands ; Peptide Fragments/*chemistry/genetics/metabolism/*pharmacology ; Protein Binding ; Receptors, Cell Surface/metabolism ; Receptors, Urokinase Plasminogen Activator ; Urokinase-Type Plasminogen Activator/*chemistry/genetics/pharmacology ; Vascular Endothelial Growth Factor A/pharmacology

BACKGROUNDTo investigate the interaction between the host cell and the truncated S fragments to identify the receptor-binding domain of the spike (S) protein of SARS-associated coronavirus (SARS-CoV).

METHODSTwo different fragments S260-600 and S397-796 of the SARS-CoV S protein were expressed in Escherichia coli (E.coli) using a pET expression vector, respectively. The two recombinant proteins were separately verified by Western blot, purified by nickel-affinity chromatography, and incubated with Vero cells, a susceptible cell line of SARS-CoV infection, for cell binding assay. After the sequential probing with sera from convalescent SARS-patients and FITC-labeled anti-human IgG, the cells were analyzed by flow cytometry. The NIH 3T3 cell, a non-permissive cell line of SARS-CoV infection, was used as controls.

RESULTSThe recombinant proteins S260-600 and S397-796 were efficiently expressed in an insoluble form in E.coli. The appropriate expression of the proteins was confirmed by Western blotting using both SARS patients' sera and anti-6 x histidine antibody. The flow cytometry results showed that the both proteins were able to bind Vero cells, but the binding ability of S260-600 was somewhat stronger than that of S397-796. In contrast, the S260-600 protein did not bind NIH3T3 cells.

CONCLUSIONBoth S260-600 and S397-796 exhibited different receptor binding activity. The S260-600 fragment probably contains the important receptor binding domain and could be a potential candidate for the development of SARS vaccine and anti-SARS therapeutics.

Animals ; Binding, Competitive ; Blotting, Western ; Cercopithecus aethiops ; Escherichia coli ; genetics ; metabolism ; Membrane Glycoproteins ; chemistry ; genetics ; metabolism ; Mice ; NIH 3T3 Cells ; Peptide Fragments ; chemistry ; genetics ; metabolism ; Protein Binding ; Receptors, Cell Surface ; metabolism ; Recombinant Proteins ; isolation & purification ; metabolism ; SARS Virus ; genetics ; metabolism ; Spike Glycoprotein, Coronavirus ; Vero Cells ; Viral Envelope Proteins ; chemistry ; genetics ; metabolism

The present study was designed to investigate polymorphism in Duffy binding protein (DBP) gene of Plasmodium vivax isolates of Korea. Thirty samples were obtained from P. vivax patients in Yonchon-gun, Kyonggi-do in 1998. The PCR products of the samples were subjected to sequencing and hybridization analyses of the regions II and IV of P. vivax DBP gene. Two genotypes, SK-1 and SK-2, were identified on the basis of amino acid substitution and deletion. The genotype of 10 isolates was SK-1 and that of 20 isolates was SK-2. Most of the predicted amino acids in the region II of DBP gene were conserved between the Korean isolates and Belem strain except for 4-5 amino acid substitutions. In the region IV of DBP, a 6-bp insert that was shown in the Sal-1 allele type was found in SK-1, and a 27-bp insert that was shown in the Papua New Guinea allele type was found in SK-2. In conclusion, the present findings suggest that two genotypes of P. vivax coexist in the endemic area of Korea.
Amino Acid Sequence ; Animals ; *Antigens, Protozoan ; Base Sequence ; Carrier Proteins/*analysis/chemistry/*genetics ; DNA, Protozoan/genetics ; Genotype ; Human ; Korea ; Malaria, Vivax/parasitology ; Molecular Sequence Data ; Plasmodium vivax/*genetics/isolation & purification ; Polymerase Chain Reaction ; *Polymorphism (Genetics) ; *Protozoan Proteins ; Receptors, Cell Surface/*analysis/chemistry/*genetics ; Support, Non-U.S. Gov't

OBJECTIVETo identify the disease-causing mutation in a Chinese family with brachydactyly type B (BDB).

METHODSGenomic DNA was extracted from peripheral blood samples of family members. Exons 8 and 9 of the ROR2 gene were amplified by polymerase chain reaction (PCR) and sequenced directly. Furthermore, the PCR products showing mutation were cloned into pMD18T vector and the insert fragments were sequenced.

RESULTSA 1398-1399 insA heterozygous mutation was detected in the patient. This mutation had been found in German families with BDB.

CONCLUSIONTo the authors' knowledge, it is the first report on identification of the ROR2 pathogenic mutation in Chinese patients with BDB.

Amino Acid Sequence ; Base Sequence ; China ; DNA ; chemistry ; genetics ; DNA Mutational Analysis ; Family Health ; Female ; Fingers ; abnormalities ; Foot Deformities, Congenital ; classification ; genetics ; Hand Deformities, Congenital ; classification ; genetics ; Humans ; Male ; Mutagenesis, Insertional ; Mutation ; Pedigree ; Receptor Tyrosine Kinase-like Orphan Receptors ; Receptors, Cell Surface ; genetics ; Sequence Deletion ; Toes ; abnormalities