[Research progress on olfactory receptor].

The olfactory perception is the process that the olfactory receptor is activated by odorous molecules, which induce the transduction of signal in the cell and the chemical information is transduced into electrical impulses. After the changed signal is transmitted to the brain, the whole perception process completes. OR gene belongs to the multigene family. The coded olfactory receptor proteins belong to the G-protein-coupled receptor (GPCR) superfamily and therefore are invariably seven-transmembrane domain(7TM) protein. Olfactory receptor protein plays an important role in olfactory perception and signal transduction process.

[Polysaccharides activate signaling pathways of macrophage].

Polysaccharides extracted from various sources are natural active substances, which may lead to the activation of macrophage via multiple pathways and mechanisms. This article intends to illustrate the signaling pathways of polysaccharides from plants, fungi, algae and other sources, to identify the mechanisms on the molecular level, and to explore the novel target immunomodulatory agents.

Characterization of polysaccharide from Astragalus radix as the macrophage stimulator.

Astragalus polysaccharide (APS) was obtained by hot water extraction, alcohol precipitation, gel-permeation chromatography and ultrafiltration. Fluorescence material 2-aminoacridone (2-AMAC) labeled APS bind to macrophage in a time- dependent manner and the binding can be remarkably inhibited by APS. Furthermore, the effect of APS on RAW264.7 macrophage demonstrated APS increase the level of cytokines including TNF-α, GM-CSF and the production of NO. NF-κB protein levels are increased in response to APS. Blocking NF-κB with specific inhibitor resulted in decreased levels of NO and TNF-α. The results suggested that APS possess potent immunomodulatory activity by stimulating macrophage and could be used as an immunotherapeutic adjuvant.

[Advances in the study of tumor pH-responsive polymeric micelles for cancer drug targeting delivery].

This review presents the state of the art of pH-responsive polymeric micelles for cancer drug delivery. Solid tumors have a weakly acidic extracellular pH (pH < 7), and cancer cells have even more acidic pH in endosomes and lysosomes (pH 4-6). The pH-gradients in tumor can be explored for tumor targeting and drug release in cancer drug delivery by applying pH-responsive polymeric micelles. The pH-responsive polymeric micelles consist of a corona and a core, and are made of amphiphilic copolymers, in which there are pH-responsive polymeric blocks. Two types of pH-responsive polymers-protonizable polymers and acid-labile polymers have been mainly used to make pH-responsive micelles for drug delivery. The protonizable polymers are polybases or polyacids, and their water-soluble/insoluble or charge states undergo changes with the protonation or deprotonation stimulated by external acidity, while the acid-labile polymers change their physical properties by chemical reaction stimulated by the acidity. Polymeric micelles whose core or coronas respond to the tumor extracellular acidity can be explored for triggering the fast release of the carried drug, activating the targeting group and accelerating the endocytosis of drug-loaded polymeric micelles, and those whose core or coronas respond to the tumor lysosomal acidity can be used for facilitating their escape from the lysosomes and targeting the nucleus. Various in vivo and in vitro experiments demonstrated that pH-responsive polymeric micelles are effective for cellular targeting, internalization, fast drug release and nuclear localization, and hence enhancing the therapeutic efficacy and reducing the side effect of cancer chemical therapy.

Mutation analysis of a large Chinese pedigree with congenital preaxial polydactyly.

Mutations in the long-range limb-specific cis-regulator (ZRS) could cause ectopic shh gene expression and are responsible for preaxial polydactyly (PPD). In this study, we analyzed a large Chinese isolated autosomal dominant PPD pedigree. By fine mapping and haplotype construction, we located the linked region to a 1.7 cM interval between flanking markers D7S2465 and D7S2423 of chromosome 7q36. We directly sequenced the candidate loci in this linked region, including the coding regions of the five genes (HLXB9, LMBR1, NOM1, RNF32 and C7orf13), the regulatory element (ZRS) of shh, the whole intron 5 of LMBR1 which contained the ZRS, and 18 conserved noncoding sequences (CNSs). Interestingly, no pathogenic mutation was identified. By using real-time quantitative PCR (qPCR), we also excluded the ZRS duplication in this pedigree. Our results indicate that, at least, it is not the mutation in a functional gene, CNS region or duplication of ZRS that cause the phenotype of this pedigree. The etiology of this PPD family still remains unclear and the question whether another limb-specific regulatory element of shh gene exists in the noncoding region in this 1.7 cM interval remains open for future research.

Localization of a novel gene for congenital nonsyndromic simple microphthalmia to chromosome 2q11-14.

Microphthalmia is a clinically and genetically heterogeneous disorder of eye development. The genetic basis of nonsyndromic microphthalmia is not yet fully understood. Previous studies indicated that disease pedigrees from different genetic backgrounds could be attributed to completely different gene loci. To investigate the etiology in a large autosomal-dominant inherited simple microphthalmia (nanophthalmia) pedigree, which is the first genetically analyzed Chinese microphthalmia pedigree, we performed a whole-genome scan using 382 micro-satellite DNA markers after the exclusion of reported candidates associated with microphthalmia. Strong evidence indicated that microphthalmia in this family was mapped to an unreported new locus on chromosome 2q. A significantly positive two-point LOD score was obtained with a maximum 3.290 at a recombination fraction of 0.00 for marker D2S2265. Subsequent haplotype analysis and recombination data further confined the disease-causing gene to a 15-cM interval between D2S1890 and D2S347 on 2q11-14. Our results further underlined the degree of heterogeneity in microphthalmia from Chinese background and localized a novel gene which regulates eye embryogenesis.

Lycium barbarum polysaccharides regulate phenotypic and functional maturation of murine dendritic cells.

Lycium barbarum polysaccharides (LBPs) have been known to have a variety of immunomodulatory functions including activation of T cells, B cells and NK cells. Dendritic cells (DC) are potent antigen-presenting cells that play pivotal roles in the initiation of the primary immune response. However, little is known about the immunomodulatory effects of LBPs on murine bone marrow derived dendritic cells (BMDC). In the present study, the effects of LBPs on the phenotypic and functional maturation of murine BMDC were investigated in vitro. Compared to the BMDC that were only subjected to treatment with RPMI1640, the co-expression of I-A/I-E, CD11c and secretion of IL-12 p40 by BMDC stimulated with LBPs (100 microg/ml) were increased. In addition, the endocytosis of FITC-dextran by LBPs-treated BMDC (100 microg/ml) was impaired, whereas the activation of proliferation of allogenic lymphocytes by BMDC was enhanced. Our results strongly suggest that LBPs are capable of promoting both the phenotypic and functional maturation of murine BMDC in vitro.

[Stimulation by Lycium bararum polysaccharides of the maturation of dendritic cells in murine bone marrow].

OBJECTIVE: To study the effect of Lycium bararum polysaccharides (LBPs) stimulation on the maturation of murine bone marrow derived dendritic cells (BMDCs). METHODS: Murine bone marrow cells were cultured in GM-CSF and IL-4 for 5 days, then were purified with a MACS column. Respectively, BMDCs were stimulated with LBPs, LPS and RPMI1640 for 2 days. Cell phenotypes and antigens uptake by BMDCs were analyzed by flow cytometry. Cytokines released by BMDCs were detected. The antigen presenting by BMDCs was evaluated by mixed lymphocyte responses. RESULT: Compared with to the BMDCs that only subjected to RPMI 1640, the expression of I-A/I-E, CD11c and secretion of IL-12 by BMDCs stimulated with LBPs were increased, the phagocytosis of FITC-dextran by BMDCs stimulated with LBPs was impaired but the activation of proliferation of allogenic lymphocytes by BMDCs was strengthened. CONCLUSION: LBPs promote not only the maturation of cultured murine BMDCs in vitro, but also the immune response initiation induced by BMDCs.

[Mechanism of oligochitosan-induced macrophage activation].

OBJECTIVE: To study the mechanism of oligochitosan-induced macrophage activation. METHODS: Oligochitosan was chemically modified with fluorophore 2-aminoacridone (2-AMAC). The cellular events of 2-AMAC-oligochitosan-macrophage interaction were analyzed with confocal laser microscopy and the fluorescence intensity of cells was analyzed by BD LSR flow cytometer. The mechanism of oligochitosan uptake by macrophages was studied by competitive inhibition test and the effect of calcium, trypsin and colchicine on oligochitosan recognition and internalization were also determined. RT-PCR was performed to investigate the level of TNF-alpha secretion. RESULT: Macrophage could bind and uptake oligochitosan, which was dependent on the temperature: the uptake proceeded rapidly at 37 degrees C and at 4 degrees C macrophage could only bind oligochitosan. EDTA decreased oligochitosan uptake. Trypsin treatment significantly reduced the internalization, and uptake was recovered by trypsin termination. Colchicine significantly inhibited the internalization process and was dose dependent. 0.1 mol/L mannose inhibited TNF-alpha expression induced by oligochitosan. CONCLUSION: Macrophage could uptake oligochitosan via mannose receptor mediated pinocytosis. Mannose receptor is crucial for the oligochitosan-induced macrophages activation.

Regulation on maturation and function of dendritic cells by Astragalus mongholicus polysaccharides.

Astragalus mongholicus polysaccharides(ASP) isolated from one of the Chinese herbs-A. mongholicus which are known to have a variety of immunomodulatory activity. However, little is known about their immunomodulatory effects on murine bone marrow (BM)-derived dendritic cells (DC). DC are professional antigen presenting cells, which are pivotal for initiation of primary immune response. In this study, the regulatory effects of ASP on maturation and function of cultured murine BM-derived DC were investigated in vitro. ASP (10, 50, 100, 250 microg/ml) could increase the co-expression of CD-11c and MHC class II molecules on DC surface, and the 100 microg/ml is the optimal dose. The ability of unstimulated DC to uptake FITC-dextran was higher than that of ASP- or LPS-treated DC. We analyzed the concentration of IL-12 secreted by DC using ELISA. ASP-treated DC secreted a higher level of IL-12 than untreated DC. And ASP- or LPS-treated DC displayed a more mature morphology, with long protrusions, while untreated-DC displayed shorter protrusions than stimulated DC.

[Interaction between polysaccharides and interferon-gamma using an improved ELISA approach].

OBJECTIVE: To establish an ELISA approach to study the interaction of polysaccharides with cytokine in vitro. METHODS: The heparin BSA complexes (HBC) were synthesized with a chemistry method and separated using a 1 X 90 cm column of Separose 4B. After identification of the complex via SDS-PAGE,the wells of ELISA plates were coated with HBC and the interaction of HBC with interferon-gamma (IFN-gamma) was detected. The effects of heparin, low molecular weight heparin (LMW heparin), chondroitin sulfate (CS), hyaluronic acid (HA) and carrageenans on the binding of HBC to IFN-gamma were tested in this system. RESULT: Human recombinant IFN-gamma bound to heparin in a concentration dependent manner, the binding of IFN-gamma to HBC was detected at the concentration of 0.25 ng, and saturated at around 2 ng. Free heparin, LMW heparin, CS,HA and carrageenans competed for the binding of IFN-gamma to HBC with significant different ability. The IC(50)concentrations of heparin and LMW heparin were 2.40 microg/ml and 18.60 microg/ml respectively. CONCLUSION: IFN-gamma is a cytokine with high binding affinity to heparin and carrageenans family but poor to CS-A and CS-C. ELISA is a simple, sensitive approach to detect the interaction of polysaccharides with cytokine in vitro.