Fan Chen

Hainan Medical College, Haikou, Yunnan, China

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Publications (9)14.32 Total impact

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    ABSTRACT: Novel antibacterial agents against Mycobacterium tuberculosis (MTB) are crucial due to the high infection and mortality rates associated with the disease. Our previous study confirmed that aptamers from a whole bacterium obtained by the Systematic Evolution of Ligands by Exponential Enrichment method specifically bound to the MTB virulent strain (H37Rv). In the present study, the function of aptamers against MTB in a mouse model was further determined. It was demonstrated that the NK2 aptamer has marked inhibitory effects on the adhesion/invasion of H37Rv to macrophages in vitro and stimulates intracellular IFN-γ production in CD4+ T-cells. The aptamer pool exhibited the strongest inhibitory effect on H37Rv adhesion/invasion to CD8+ T-cells in vitro compared with all aptamers-treated and control groups. Histopathological examination of lung biopsy specimens revealed a correlation between aptamer presence and lower pulmonary alveoli fusion, swelling and more prominent air spaces. Acid-fast staining of biopsy specimens from the lungs of the mice demonstrated parallel treatment effects. Results of the present study indicate that the 10th pool aptamers and NK2 may play an active role against H37Rv, however, the effect was different in vivo and in vitro. The treatment effect of 10th pool aptamers was found to be better in comparison to NK2 in vivo. Additional target sites involved in pathogenicity of H37Rv were also revealed and the NK2 binding site and aptamers, including the 10th pool aptamers, may antagonize these sites. Further studies are required to screen for other valuable aptamers which may be used as therapeutic drugs in combination with NK2.
    Molecular Medicine Reports 12/2012; 7(2). DOI:10.3892/mmr.2012.1229 · 1.48 Impact Factor
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    ABSTRACT: Fibroblast growth factor receptor 2 (FGFR2), a recently described risk factor for breast cancer, plays important roles in cell growth, invasiveness, motility, and angiogenesis. In attempt to investigate whether FGFR2 polymorphisms are associated with a risk of breast cancer in Chinese women of the Han nationality, we genotyped single-nucleotide polymorphisms (SNPs) of seven FGFR2 sites (rs2981582, rs17102287, rs17542768, rs10510097, rs11200012, rs3750817, rs2981578) in 816 women including 388 breast cancer patients and 428 healthy controls via the polymerase chain reaction single-strand conformation polymorphism procedure as well as sequence detection. Our results suggest that the A allele and AA genotype of SNP rs2981578 appear to be protective factors associated with breast cancer, while the CT genotype of SNP rs3750817 is a putative risk factor.
    Immunogenetics 08/2011; 64(1):71-6. DOI:10.1007/s00251-011-0564-2 · 2.49 Impact Factor
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    ABSTRACT: There is an urgent need to develop new anti-tuberculosis drugs due to the rising tendency in tuberculosis (TB) around the world. It is known that Mycobacterium tuberculosis (M. tuberculosis) generally infects mammalian host via aerosol route. The pathogenic process has been fully studied that it can initially invade alveolar macrophage, then established stable residence within those phagocytic cells, suggesting that one of the possible ways to prevent this pathogen is to inhibit its invasion and growth in the macrophage. Aptamers from SELEX (Systematic Evolution of Ligands by Exponential Enrichment) have been used to rival virulent M. tuberculosis (H37Rv) in our previous work, and the materials to which aptamers bound were proved to be some outer membrane proteins of H37Rv. In the present study, the interaction between M. tuberculosis and macrophage in the presence of aptamers was investigated in more details. The results suggested that the selective aptamers significantly inhibited H37Rv invasion of macrophage in vitro, and the effect correspond to the binding affinity of these aptamers to H37Rv. The values of equilibrium dissociation constant (Kd) was calculated by flow cytometry, all in the nanomolar range, showed much higher affinity to H37Rv than M. bovis Bacillus Guerin (BCG). Moreover, the aptamer-treated H37Rv can stimulate IFN-γ, IL-15 and IL-17 secretion of macrophages compared with H37Rv (no treated). In summary, our data indicated that the NK2 aptamer not only acted as anti-tuberculosis agent by inhibiting virulent M. tuberculosis (H37Rv) invasion of macrophage, but also might be used as molecular probe for exploring the interaction between the outer membrane of M. tuberculosis and macrophage.
    Molecular Biology Reports 06/2011; 39(3):2157-62. DOI:10.1007/s11033-011-0963-3 · 1.96 Impact Factor
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    ABSTRACT: Objective To explore the effect of hepatocyte growth factor signaling pathway activation on Plasmodium berghei infection.
    Asian Pacific Journal of Tropical Medicine 03/2010; 3(3):169-172. DOI:10.1016/S1995-7645(10)60001-6 · 0.93 Impact Factor
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    ABSTRACT: This study reports that Escherichia coli phosphatidylcholine-positive (PC+) strain Top10/ptac66 (PC+ PE+), in which borrelial PC synthase (PCS) directly condenses exogenous choline with CDP-diacylglycerol (CDP-DAG) to form PC, displayed not only stronger resistance to antimicrobial peptides cecropin P1 and indolicidin, but also decreased ability to attract macrophages to the abdominal cavity of infected mice in the 36 h following infection, compared with the control strain Top10/ptac85 (PC- PE+). Rabbit sera raised against the PC+ strains Top10/ptac66 (PC+ PE+) and AD93/ptac67 (PC+ PE-) recognized a different set of periplasmic proteins and lipopolysaccharides,compared with those detected by antisera to the PC- strains Top10/ptac85 and AD93 (PC- PE-) . Electron microscopy also showed that the morphology of cell wall of Top10/ptac66 was different from that of the control strain Top10/ptac85. Enhancement of bacterial resistance to antimicrobe peptides, alteration of bacterial antigenicity and evasion of macrophage attacks in mice suggest that PC in the bacterial membrane may play a role in bacterial evasion of the innate or adaptive immune response of the host.
    Canadian Journal of Microbiology 11/2009; 55(11):1328-34. DOI:10.1139/w09-082 · 1.18 Impact Factor
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    ABSTRACT: The major histocompatibility complex (MHC) class I-related molecules A (MICA) is a stress-inducible cell surface antigen that is recognized by intestinal epithelial Vdelta1 gammadelta T cells, natural killer (NK) cells and CD8(+) T cells with NKG2D receptor participating in the immunological reaction in the intestinal mucosa. The present study aimed to investigate the functions of the MICA*A5.1 allele in the development of ulcerative colitis (UC) in the Chinese population. The microsatellite polymorphisms of MICA were genotyped in 124 unrelated Chinese patients with UC and 172 ethnically matched healthy controls using a semiautomatic fluorescently labelled polymerase chain reaction. MICA*A5.1-expressing Raji cells were generated by gene transfection. Cytotoxicity of NK cells to Raji cells expressing different MICA molecules was detected using the lactate dehydrogenase method. Soluble MICA in the culture supernatant was detected by enzyme-linked immunosorbent assay. The frequency of MICA*A5.1 was significantly higher in UC patients compared with the healthy controls (29.0% versus 17.4%, P = 0.001, corrected P = 0.005, OR = 1.936, 95% CI 1.310-2.863) and the frequency of a MICA*A5.1/A5.1 homozygous genotype was increased in UC patients (18.5% versus 7% in healthy controls, P = 0.0032, corrected P = 0.048, OR = 3.036, 95% CI 1.447-6.372). Raji cells with MICA*A5.1 expression produced more soluble MICA (t = 5.75, P < 0.01) than Raji cells with full-length MICA expression in culture supernatant. Raji cells with MICA*A5.1 expression were more resistant to killing by NK cells than Raji cells with full-length MICA expression. The MICA*A5.1 allele and MICA*A5.1/A5.1 genotype are significantly associated with Chinese UC patients in central China. MICA*A5.1 may play a role in the development of UC by producing more soluble MICA and resistance to NK cells.
    Immunology 09/2009; 128. DOI:10.1111/j.1365-2567.2008.02953.x · 3.74 Impact Factor
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    ABSTRACT: Interleukin-5 (IL-5) involves in the development of airway inflammation and hyperresponsiveness through activation of eosinophils. Thus, inhibition of IL-5 expression seems to be an attractive approach for asthma therapy. In this study, an antisense IL-5 gene transferred by recombinant adeno-associated virus (asIL-5) was constructed to transfect murine allergic asthma model. Our results showed that asIL-5 efficiently inhibited the IL-5 mRNA expression and significantly attenuated the inflammation in lung tissues. Significant decreasing of eosinophils and inflammatory cells were found in peripheral blood and bronchoalveolar lavage fluid (BALF). In addition, significant inhibition of airway hyperresponsiveness (AHR) was also found in the mice treated with asIL-5. These observations demonstrate that antisense oligonucleotid against IL-5 delivered by adeno-associated virus system is possibly an efficacious therapeutic strategy for allergic asthma and other eosinophil-related disorders.
    Asian Pacific journal of allergy and immunology / launched by the Allergy and Immunology Society of Thailand 04/2009; 27(1):35-41. · 1.26 Impact Factor
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    ABSTRACT: Interleukin-5 (IL-5) accompanies the development of airway inflammation and hyperresponsiveness through the activation of eosinophils. Therefore, interference of IL-5 expression in lung tissue seems to be an accepted approach in asthma therapy. In this study, we designed a small interfering RNA (siRNA) to inhibit the expression of IL-5. The siRNAs against IL-5 were constructed in a lentivirus expressing system, and 1.5x10(6) IFU (inclusion-forming unit) lentiviruses were administered intratracheally to ovalbumin (OVA)-sensitized murine asthmatic models. Our results show that lentivirus-delivered siRNA against IL-5 efficiently inhibited the IL-5 messenger ribonucleic acid (mRNA) expression and significantly attenuated the inflammation in lung tissue. Significant decrease of eosinophils and inflammatory cells were found in peripheral blood, bronchoalveolar lavage fluid (BALF), and lung tissue. In addition, significant inhibition of airway hyperresponsiveness (AHR) was found in the mice treated with siRNA against IL-5. These observations demonstrate that siRNA delivered by means of the lentivirus system is possibly an efficacious therapeutic approach for asthma.
    Journal of Zhejiang University SCIENCE B 01/2009; 10(1):22-8. DOI:10.1631/jzus.B0820226 · 1.29 Impact Factor