Research progress of small molecule fluorescent probes for ferrous ion and heme / 药学学报

Small molecule fluorescent probes have gained widespread attention for their advantages of high selectivity, sensitivity, and easy to operate, and have played a critical role in the detection of various species. They have also demonstrated great potential in the field of biomedical research. Iron, as the most abundant transition metal in the human body, plays a vital role in many physiological functions. Due to the influence of the reductive microenvironment of cell, ferrous ion (Fe2+) is the main component of labile iron in living cells. Heme, consisting of Fe2+ and protoporphyrin IX, is one of the main signaling molecules that wrap biological iron in the human body, and also participates in many physiological and pathological processes. Therefore, the development of small molecule fluorescent probes for detecting Fe2+ and heme as effective monitoring tools will help to further understand their pathological and physiological functions, with potential applications in other fields. This review summarizes the research progress of small molecule fluorescent probes for Fe2+ and heme detection in recent years, and provides insights into future directions for their development.

Sinomenine promotes paired immunoglobulin-like receptor B expression to restrain macrophage classic activation / 药学学报

In this study, in vitro experiments were conducted to investigate that sinomenine inhibits the macrophage classic activation by up-regulating the expression of paired immunoglobulin-like receptor B (PIR-B). A macrophage model with classic activation was established by lipopolysaccharide and interferon-gamma co-stimulation. Real-time fluorescence reverse transcription-polymerase chain reaction was executed for evaluating the PIR-B gene expression, and Western blot for PIR-B protein expression, in macrophages, respectively. The tumor necrosis factor α and interleukin 8 in cell culture supernatant were measured by enzyme-linked immunosorbent assay. The flow cytometry was utilized to detect M1 macrophages. The PIR-B expression in situ was observed by laser scanning confocal microscope. The results showed that sinomenine significantly increased the expression of PIR-B, markedly reduced the percentage of M1 macrophages, and decreased the levels of tumor necrosis factor α and interleukin 8 in the culture supernatant. The above results indicated that sinomenine can significantly inhibit the macrophage classic activation, and its mechanism may be related to the increase of PIR-B expression in macrophages. This pharmacological effect helps explain the pharmacodynamic mechanism of sinomenine in treating rheumatoid arthritis.

JAK2V617F mutation and p-STAT5 protein expression in peripheral blood cells of patients with myeloproliferative neoplasm and their relations with clinical features / 中国实验血液学杂志

This study was aimed to explore the JAK2V617F mutation and p-STAT5 expression in patients with myeloproliferative neoplasm (MPN), and investigate their relations with clinical characteristics so as to provide theoretical basis for clinical practice and target therapy. Forty-five confirmed BCR-ABL-negative MPN patients and 15 healthy adults were enrolled in this study. Real-time fluorescent quantitative PCR and Western blot were respectively used to detect JAK2V617F mutation proportion and p-STAT5 expression level. In addition, their relations with clinical characteristics of MPN were analyzed. The results showed that the positive rate of JAK2V617F mutation in MPN patients was 73.3% (33/45), including 83.3% in polycythemia vera (PV) patients (20/24), 68.8% in essential thrombocythemia (ET) patients (11/16) and 40.0% in idiopathic myelofibrosis (IMF) patients (2/5). Mutation proportions of JAK2V617F in PV, ET and IMF patients were 0.472 ± 0.245, 0.216 ± 0.162, 0.435 ± 0.239 respectively; gray values of p-STAT5 protein in PV, ET and IMF patients were 1.396 ± 0.758, 0.760 ± 0.623, 0.792 ± 0.612 respectively. JAK2V617F mutation proportion and p-STAT5 protein expression level showed a linear correlation (P < 0.05). PV patients with higher JAK2V617F mutation proportion had higher white blood cell count, hemoglobin level and hematocrit, but lower platelet count; ET patients with higher mutation proportion showed older and higher white blood cell count, hemoglobin level and hematocrit, there was no significant difference between platelet count; IMF patients with higher JAK2V617F mutation proportion showed lower white blood cell count, platelet count, hemoglobin level and hematocrit. Patients with JAK2V617F positive mutation were more likely complicated by splenomegaly, bleeding and thrombotic events. It is concluded that the incidence rate of JAK2V617F mutation is high in patients with MPN. Higher mutation proportion always connected with higher expression of p-STAT5, and easily complicates by splenomegaly and thrombotic events.

Effect of methylation inhibitor on EphB4 gene expression, proliferation and apoptosis in CEM cells / 中国当代儿科杂志

<p><b>OBJECTIVE</b>To study the regulation of methylation inhibitor 5-aza-2'-deoxycytidine on transcription of EphB4 gene and effects on the proliferation and apoptosis of human acute lymphocyte leukemia cell line CEM.</p><p><b>METHODS</b>Bisulfite sequencing PCR was used to detect CpG island methylation density in EphB4 promoter. The expression of EphB4 mRNA and protein was determined by Q-PCR and Western blot. MTS assay and flow cytometry were used to detect the apoptosis of CEM cells after treatment with different concentrations of 5-aza-2'-deoxycytidine (1.0, 2.5 and 5 μmol/L).</p><p><b>RESULTS</b>Methylation of EphB4 gene promoter was detected in CEM cells (31.4%). The methylation level of EphB4 gene was down-regulated after treatment with various concentrations of 5-aza-2'-deoxycytidine. The EphB4 mRNA and protein expression in CEM cells increased after 5-aza-2'-deoxycytidine treatment. 5-Aza-2'-deoxycytidine significantly inhibited the cell growth in dose and time dependent manners. Early apoptosis rates of CEM cells increased from 4.1% to 24.8% 96 hrs after 5-aza-2'-deoxycytidine treatment. CEM cells in G1 phase decreased from 62.4% to 46.8%, cells in G2 phase increased from 2.1% to 16.2%, and CEM cells were arrested in G2 phase after treatment with 5 μmol/L 5-aza-2'-deoxycytidine for 96 hrs.</p><p><b>CONCLUSIONS</b>5-Aza-2'-deoxycytidine, an inhibitor of specific methylation transferase, can induce expression of the silent EphB4 gene in CEM cells, inhibit the proliferation of leukemia cells and induce cell apoptosis.</p>

Genetic polymorphism of GST gene in children with infectious mononucleosis and acute lymphocytic leukemia / 中国当代儿科杂志

<p><b>OBJECTIVE</b>To study the relationship between glutathione S-transferase genes GSTT1 and GSTM1 polymorphisms and the susceptibility to infectious mononucleosis (IM) and acute lymphocytic leukemia (ALL) in children.</p><p><b>METHODS</b>The case-control study involved 106 children with IM, 41 children with ALL and a control group of 100 children with non-hematologic and nontumorous diseases. The genetic polymorphisms of GSTT1 and GSTM1 were detected with multiplex polymerase chain reaction (PCR). Distribution of the genotypes in the children was analyzed.</p><p><b>RESULTS</b>The frequency of GSTT1 null genotype in children with IM was significantly higher than in the control group (P<0.05). The risk of IM in children carrying GSTT1 null genotype was 2.186 times higher than in those carrying GSTT1 non-null genotype. The children carrying both GSTT1 and GSTM1 null genotype had a higher risk of suffering from IM compared to those carrying only one of the null genotypes (OR=4.937). The frequency of GSTM1 null genotype in children with ALL was significantly higher than in the control group (P<0.05). The risk of ALL in children carrying GSTM1 null genotype was 2.242 times higher than in those in carrying GSTT1 non-null genotype. Children carrying both GSTT1 and GSTM1 null genotype had a higher risk of suffering from ALL compared with those carrying only one of the null genotypes (OR=8.552).</p><p><b>CONCLUSIONS</b>Children carrying GSTT1 or GSTM1 null genotype have a high risk of suffering from IM or ALL. Still more increased susceptibility to IM or ALL may occur in children who carry both GSTT1 and GSTM1 null genotype. GSTT1 and GSTM1 might play a potential role in the pathogenesis of both IM and ALL.</p>

Secretory expression and biological activity analysis of an anti-H5 single-chain antibody from Pichia pastoris / 病毒学报

In our previous study, a panel of 52 broadly cross-reactive H5-specific monoclonal antibodies (MAbs) were generated and characterized. The 13D4, one of these MAbs, has been demonstrated to protect mice against lethal challenge by 4 strains of H5N1 avian influenza virus representing the currently prevailing genetic populations, clades 1, 2.1, 2.2, and 2.3. Here, we further cloned the gene of the 13D4 MAb and constructed a single-chain variable fragment. Then, the 13D4 single-chain antibody (scFv) was expressed in secretory maner in Pichia pastoris. The supernatant of the culture was concentrated and subjected to ammonium sulfate precipitation. The purity of the 13D4 scFv was around 90% in SDS-PAGE following ion-exchange chromatography. We further investigated its binding property using hemagglutination inhibition (HI) test and blocking ELISA. The results indicated that the 13D4 scFv shared the same binding sites and comparable HI titer with the prototype murine 13D4 Mab. In conclusion, an anti-H5 single-chain wide-spectrum neutralizing antibody is prepared successfully in yeast system.

Progress of study on JAK2V617F mutation in myeloproliferative neoplasm / 中国实验血液学杂志

Myeloproliferative neoplasms (MPN) are clonal hematopoietic stem cell diseases characterized by proliferation of one or more myeloid cell lineages in the bone marrow and increased mature and immature cells in peripheral blood. As the most important discovery in recent studies of MPN, JAk2V617F mutation is considered to closely relate with the pathogenesis of MPN. The mutated JAK2 lost self-inhibition, and then, the sustained activation leads to a series of disorders in downstream signal transduction pathways, eventually resulting in malignant cell proliferation. A variety of methods have been used in quantitative/qualitative detection of JAK2V617F mutation, and researches about JAK2V617F mutation and its clinical features have also made some progress. However, it must be noted that there are still some unsolved problems, such as the role of JAk2V617F mutation in pathogenesis of MPN needs further exploration, effective targeted therapy for JAK2 is a attractive topic, and the application of JAK2V617F mutation in disease diagnosis also requires a deep research. In this review, the latest progress from different aspects is summarized briefly, including JAK2 and JAK2V617F mutation, effects of JAK2V617F mutation on the pathogenesis, clinical correlation of JAK2V617F with MPN, and targeting therapy.

The preliminary analysis of the recognition epitopes of anti-HEV monoclonal antibodies on HEV ORF2 / 病毒学报

Western blot, capture-PCR, blocking ELISA and synthetic polypeptides were used to systematically study the recognition epitopes on HEV ORF2 of 23 anti-HEV monoclonal antibodies(McAbs) which were previously generated in our laboratory directed against HEV ORF2. Results showed that seven McAbs recognized linear epitopes that located at aa408-458 of HEV ORF2 and 16 conformation-dependent McAbs, most of which recognized the surface epitopes of native HEV, located at aa459-606 of HEV ORF2. The systematical study of the recognition epitopes of anti-HEV McAbs on HEV ORF2 provides important information for the investigation of virus receptor and HEV infection mechanism, as well as its vaccine and diagnostics development.

Identification of peptide mimotopes of an abroad-spectrum neutralizing epitope of highly pathogenic avian influenza hemagglutinin / 病毒学报

A monoclonal antibody (8H5), which showed strong neutralization activity against 33 strains of H5N1 viruses isolated from hosts at various regions from 2002 to 2006, was characterized in our lab recently. This result indicated the presence of highly conserved neutralizing site on hemagglutinin (HA) of various H5N1 subtypes. In the present study, the peptide phage display technique was applied to generate mimotope of the conserved neutralizing epitope recognized by 8H5 mAb. Five peptides displayed on phage were identified to specifically bind to 8H5 mAb. One of the five peptides, 123, was further displayed on the virus-like particle assembled from aa 1-149 fragment of HBcAg. The chimeric particle HBc-T123 conserved the specific binding to 8H5 mAb, and competed with H5N1 viruses for 8H5 mAb. The antiserum induced by HBc-T123 intensively stained on SF21 cells infected by recombinant baculovirus containing HA gene of YU22 virus, indicating the production of cross-reactive antibody to H5N1 HA.

Effect of integrin alpha2beta1 on invasion and migration of neuroblastoma cells / 中国当代儿科杂志

<p><b>OBJECTIVE</b>To study the effect of integrin alpha2beta1 on invasion and migration of SK-N-SH neuroblastoma cells.</p><p><b>METHODS</b>Neuroblastoma SK-N-SH cell line was cultured in the modified eagle's medium. The effects of monoclonal antibodies to integrin alpha2 and integrin beta1 on migration and invasion were measured by inclined test and polycarbonate filters incorporated in modified Transwell chambers respectively. The migration and invasion cells were stained with Gimsa staining and counted under a 200 multiplied microscope. The blocking rate of migration and invasion of cells was calculated.</p><p><b>RESULTS</b>The number of migrated SK-N-SH cells in the anti-alpha2 and anti-beta1 treatment groups (50.9+/-10.5 and 54.3+/-9.0 respectively) was significantly less than that in the control group without monoclonal antibody treatment (98.1+/-7.4) (P<0.01), with a blocking rate of cell migration of 48.1% and 44.5% respectively. The invasion to matrigel of SK-N-SH cells exposed monoclonal antibodies to integrin alpha2 and integrin beta1 was significantly blocked compared with the control SK-N-SH cells, with the number of invasion cells in the anti-alpha2 and anti-beta1 treatment groups of 25.3 +/- 4.4 and 18.8 +/- 3.9 respectively vs 41.5 +/- 4.8 in the control group (P<0.01). The blocking rate of cell invasion in the anti-alpha2 and anti-beta1 treatment groups was 39.0% and 54.7% respectively.</p><p><b>CONCLUSIONS</b>Integrin alpha2beta1 may promote migration and invasion of neuroblastoma cells.</p>

Effect of endogeneous gangliosides on integrin alpha2beta1-mediated adhesion of neuroblastoma cells to collagen / 中国当代儿科杂志

<p><b>OBJECTIVE</b>To study the effect of endogeneous gangliosides (Gls) on integrin alpha2beta1-mediated adhesion of neuroblastoma cells to collagen (Col).</p><p><b>METHODS</b>Neuroblastoma SK-N-SH cell line was cultured in the modified eagle's medium with the presence of 10 mum D-threo-1-phenyl-2-decanolamino-3-morphinolin-1-propanol (D-PDMP), an inhibitor of glucosylceramide synthase. Flow cytometry was used to detect the expression of integrin alpha2beta1 in the cell line. The effects of Mg2(+) and monoclonal antibodies to integrin alpha2beta1 on the adhesion of the cell line to immobilized Col were observed. The adhesion cell number was measured with the BCA method and presented with absorptance A570.</p><p><b>RESULTS</b>There was a high expression of integrin alpha2beta1 in the SK-N-SH cell line without D-PDMP treatment. Endogenous Gls in the cells were almost depleted after 6-day exposure to D-PDMP, but the integrin alpha2beta1 expression was not significantly changed. 1 mmoL/L Mg2(+) treatment increased significantly the number of adhesion cells in the SK-N-SH cell line. The adhesion to Col of the SK-N-SH cells exposed to D-PDMP which Gls was depleted was significantly reduced compared with the control SK-N-SH cells treated with 1 mmoL/L Mg2(+) (A570: 0.33 +/- 0.016 vs 0.57 +/- 0.033; P < 0.01). After endogeneous Gls was added into the Gls-depleted SK-N-SH cells, the adhesion of the cells was restored (A570: 0.52 +/- 0.035). The adhesion of SK-N-SH cells was significantly blocked by anti-alpha2 and anti-beta1 monoclonal antibodies, with A570 of 0.31 +/- 0.018 and 0.36 +/- 0.021 respectively.</p><p><b>CONCLUSIONS</b>Endogenous tumor Gls increases neuroblastoma cell adhesion to Col by regulating the function of integrin alpha2beta1, but has no effects on the integrin expression. It is suggested that tumor Gls may play a role in migration, invasion and metastasis of tumor cells.</p>

Effect of Endogeneous Gangliosides on pp125 Focal Adhesion Kinase Expression during Adhesion of SK-N-SH Neuroblastoma Cells to Collagen / 实用儿科临床杂志

Objective To explore effect of endogeneous gangliosides(Gls) and integrin ?2?1 on protein phosphotyrosine expression of pp125 focal adhesion kinase (pp125FAK) after adhesion of SK-N-SH neuroblastoma cells to collagen(Col).Methods SK-N-SH cell line with high expression of integrin ?2?1 was cultured in presence of D-threo-1-phenyl-2-decanolamino-3-morphinoline-1-propanol(D-PDMP).Effect of endogeneous Gls,anti-?2 and anti-?1 monoclonal antibody on protein phosphotyrosine expression of pp125FAK during adhesion of SK-N-SH cells to Col were determined by immunoprecipitate and Western blotting.Results After 6 days,endogenous Gls in cells were almost depleted.Gls-depletion,anti?2 and anti-?1 monoclonal antibody were able to decrease pp125FAK expression of SK-N-SH cells adherent to Col respectively.GD2,the major component of neuroblastoma cell Gls could reco-ver pp125FAK expression to a certain degree.Conclusions Endogenous tumor Gls regulate protein phosphotyrosine expression of pp125FAK during adhesion of neuroblastoma cells to Col.It is suggested that tumor Gls may increase signal transduction of tumor cell integrin ?2?1 by increasing tyrosine phosphorylation of pp125FAK.

Establishment and application of human papillomavirus type 16 pseudovirions neutralization assay / 生物工程学报

Human papillomaviruses (HPV) are causally associated with cervical cancer and genital warts. Lack of permissive and productive cell cultures for HPV has hindered the study of HPV and evaluation of virus-neutralizing antibodies. So generation of infectious virions in vitro is highly desirable. In this report, we got high titer infectious HPV16 pseudovirions by calcium phosphate co-transfection of codon optimized HPV16 capsid genes L1 and L2 and reporter plasmids into 293FT cell line. Electron micrograph indicated that the pseudovirions were morphologically similar with the intact HPV16 virions. To evaluate the feasibility of using the pseudovirions to identify neutralizing monoclonal antibodies (mAbs), pseudovirions were incubated with 2-fold gradient dilution of the well identified mAbs V5, E70, U4 and D9 and then used to infect 293FT cells preplated in 96-well tissue culture plate. The infection of pseudovirions could be inhibited by neutralizing mAbs V5, E70 and U4 that recognize surface conformational epitopes on L1 VLP, but not by mAb D9 that is reactive to a linear epitope buried in VLP, which indicated that the pseudovirions could be used to evaluate the neutralization efficiency of mono- and polyclonal antibodies. The pseudovirions were then employed to identify neutralizing mAbs from 18 mAbs generated previously in our lab, 8 of which were conformational and 10 were linear. PD1 and 3D10, both of which recognized conformational epitopes on L1 VLP, had obviously strong neutralizing efficiency, with the neutralizing titer reached 81,920 and 20,480 respectively, while none of the linear mAbs were neutralizing, which reflected that rare linear mAbs have neutralization activity. The mechanism of PD1 and 3D10 block the infection of HPV16 pseudovirions need to be further studied. The technologies about generation of HPV16 pseudovirions and screening neutralizing mAb in our report are economical and efficient, can be easily used in large scale. They pave the way for rapid and precise evaluation of the protection efficiency of our prophylactic HPV vaccine being developed now.

Interface domain of hepatitis E virus capsid protein homodimer / 生物工程学报

Hepatitis E is a main cause of acute viral hepatitis in developing countries where it occurs as sporadic cases and in epidemics form. The causative agent, hepatitis E virus, is transmitted primarily by the fecal-oral route. The approximately 7.5 kb positive-sense single-strand RNA genome includes three open reading frames (ORFs), one of which (ORF2) is postulated to encode the major viral capsid protein (pORF2) of 660 amino acid residues. We earlier showed that a bacterially expressed peptide, designated as NE2, located from amino acid residues 394 to 606 of ORF2, was found to aggregate into homodimer to at least hexamer. To understand the interface domains within this peptide vital for dimerization and formation of major neutralizing epitopes, NE2 protein underwent terminal-truncated and site-directed mutation. The hydrophobic region, ORF2 aa597-aa602 (AVAVLA), played a key role in oligomerization. Any amino acid residue of this region replaced with glutamic acid residue, the peptide can not refold as homodimer and/or oligomer. The immunoreactivities of these mutant peptides, blotted with anti-HEV neutralizing monoclonal antibody (8C11) and convalescent human sera, show associated to the formation of homodimer. The intermolecular contact region on homodimer was investigated by chemical cross-linking of two site-directed cysteines. When the alanine on aa597 site mutated with cysteine, two different homodimers were found in SDS-PAGE analysis. One (42kD) can be disassociated with 8mol/L urea, which is postulated to form by virtue of hydrophobic interaction, and the other (60kD) falls apart with the reductant DTT present. The exact conformation, generating the cross-linking reaction of cysteines, was further investigated by induced-oxidation on monomer and hydrophobic homodimer of A597C protein with GSH/GSSG. And the results revealed, it is the conformation of hydrophobic homodimer that induces the disulfide bond come into being, instead of the one of monomer. So the aa597 site was verified to be located on interface domain of hydrophobically interacting homodimeric complex. To evaluate the biological significance of hydrophobicity of interface domain, we searched natural variations as to the region on all available databases with NCBI blast program. All variations on these amino acid residues kept higher hydrophobicity, which suggests that the hydrophobic domain is critical for the assemblage and propagation of HEV. NE2 N-terminal deletions up to aa458 had no effect on dimerization and took no exact part in formation of major neutralizing epitopes, but the fragment may act as helper for the formation of major neutralizing epitopes on NE2. Interestingly, the C-terminus aa605-aa660 of ORF2 can also act as helper instead of the N-terminus of NE2. This study suggests an interface domain of NE2 might be vital for HEV capsomer assembly and formation of major neutralizing epitopes. These results may offer clues to the rational design of recombinant anti-HEV vaccine.

Particulate recombinant hepatitis E virus capsid protein and its antigenicity and immunogenicity / 生物工程学报

An E. coli expressed recombinant antigen NE2 was reported to aggregate into homo-oligomer, and can induce protective antibodies on rhesus monkey, but its immunogenicty was much weak after being purified. In this study, three N-terminal extension mutant of NE2 were expressed in E. coli, one of which named HEV 239 was found to aggregate into particle. HEV 239 antigen had good reactivity with sera of hepatitis E patients. The reactivity of HEV 239 against neutralization monoclonal antibody 8C11 was similar as NE2 antigen, while the reactivity of it against another neutralization monoclonal antibody 8H3 is much better than NE2 antigen, which indicated better antigenicity of HEV 239 than NE2. The diameter of purified HEV 239 particulate antigen was between 15 nm to 30 nm. The ED50 of immunization of HEV 239 particle adsorbed by aluminum adjuvant to BALB/c mice was between 0.08 microg to 0.25 microg. In contrast, the seraconversion rate of mice immunized by NE2 antigen adsorbed by aluminium adjuvant was only 25% on 60 microg vaccination. These results suggested that HEV 239 antigen particle has better immunogenicity as well as antigenicity than those of NE2 antigen, so it is a better vaccine candidate against HEV.