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21.
CD11b/CD18-dependent interactions of neutrophils with intestinal epithelium are mediated by fucosylated proteoglycans 总被引:6,自引:0,他引:6
CD11b/CD18-mediated adhesive interactions play a key role in regulating polymorphonuclear leukocytes (PMN)) migration across intestinal epithelium. However, the identity of epithelial ligands for migrating PMN remains obscure. In this study we investigated the role of carbohydrates in mediating adhesive interactions between T84 intestinal epithelial cells and CD11b/CD18 purified from PMN. Fucoidin, heparin/heparin sulfate, N-acetyl-D-glucosamine, mannose-6-phosphate, and laminarin were found to inhibit adhesion of T84 cells to CD11b/CD18. The most potent inhibitory effects were observed with fucoidin (50% inhibition at 1-5 x 10(-8) M). Binding assays demonstrated that fucoidin directly bound to CD11b/CD18 in a divalent cation- and sulfation-dependent fashion that was blocked by anti-CD11b mAbs. Experiments employing CD11b/CD18 as a probe to blot T84 cell fucosylated proteins purified via fucose-specific lectin column revealed several candidate CD11b/CD18 binding proteins with molecular masses of 95, 50, 30, 25, and 20 kDa. Fucosidase treatment of T84 cells resulted in significantly reduced cell adhesion to CD11b/CD18, while no inhibition was observed after neuraminidase treatment. Finally, significant inhibition of T84 cell adhesion to CD11b/CD18 was observed after blocking cell proteoglycan synthesis with p-nitrophenyl-beta-D-xylopyranoside. These findings implicate epithelial cell surface proteoglycans decorated with sulfated fucose moieties as ligands for CD11b/CD18 during PMN migration across mucosal surfaces. 相似文献
22.
As a 'double-edged sword', neutrophil (polymorphonuclear leukocyte) migration across epithelial-lined organs is an important component of host defense, but it also results in epithelial pathophysiology and disease symptoms. There have been significant advances in better understanding the mechanisms of how leukocytes cross the vascular endothelium to exit the bloodstream; however, many of the mechanisms that govern polymorphonuclear leukocyte transepithelial migration are different and we are only just beginning to understand them. Recent findings include new junctional adhesion molecules and carbohydrate moieties as receptors for migrating neutrophils. In addition, new insights into leukocyte-epithelial signaling events have emerged that are beginning to shed light on the role of SIRP-CD47 interactions in regulating the rate of neutrophil transepithelial migration and how neutrophils modulate epithelial barrier function. 相似文献
23.
Hisashi Koike Zen Kouchi Tadatoshi Kinouchi Tatsuya Maeda Hiroyuki Sorimachi Takaomi C. Saido Kei Maruyama Akira Okuyama Koichi Suzuki Shoichi Ishiura 《Cytotechnology》2000,33(1-3):213-219
Thimet oligopeptidase (TOP) is a thiol- andmetallo-dependent peptidase and has been shown to beone of the -secretase candidates. TOPexpressed in COS cells cleaved amyloid precursorprotein (APP) at the -secretase site, and wefound a proteolytic product of APP called secretedform of APP by -secretase (sAPP) in theconditioned media. Here we demonstrate thatsAPP was increased in conditioned media whenTOP was coexpressed in COS cells with APP and treatedwith an ADAM inhibitor SI-27. In addition, althoughTOP expressed in COS cell was localized at nuclei orGolgi apparatus, it exclusively colocalized at Golgiapparatus when APP was coexpressed with TOP. 相似文献
24.
25.
Light signaling plays a pivotal role in controlling plant morphogenesis, metabolism, growth and development. The central process of light signaling pathway is to build the link between light signals and the expression of genes involved. Although studies focused on light signaling toward metabolism have been documented well in the past several decades, most regulation networks of light signaling in a specific metabolic production largely remained unknown. Anthocyanin accumulation in plant tissues depends on the availability of light signals, but only little is known about the potential regulation network underlying light signal controls anthocyanin biosynthesis. Here, we briefly review the recent progress on the light-triggered anthocyanin biosynthesis via ANGUSTIFOLIA3 (AN3) and CONSTITUTIVE PHOTOMORPHOGENIC1 (COP1) network in Arabidopsis. 相似文献
26.
Yuwei Wang Xuefeng Shan Zhi Liang Youlan Shan Wenxiang Huang Dazhi Zhang Aizhong Zen Xin Zhou Yao Zhao Xuyang Gong Ge Xu Xiuyu Zhang Juan Chen Ailong Huang 《PloS one》2015,10(6)
Background
Viral genotype shift in chronic hepatitis B (CHB) patients during antiviral therapy has been reported, but the underlying mechanism remains elusive.Methods
38 CHB patients treated with ADV for one year were selected for studying genotype shift by both deep sequencing and Sanger sequencing method.Results
Sanger sequencing method found that 7.9% patients showed mixed genotype before ADV therapy. In contrast, all 38 patients showed mixed genotype before ADV treatment by deep sequencing. 95.5% mixed genotype rate was also obtained from additional 200 treatment-naïve CHB patients. Of the 13 patients with genotype shift, the fraction of the minor genotype in 5 patients (38%) increased gradually during the course of ADV treatment. Furthermore, responses to ADV and HBeAg seroconversion were associated with the high rate of genotype shift, suggesting drug and immune pressure may be key factors to induce genotype shift. Interestingly, patients with genotype C had a significantly higher rate of genotype shift than genotype B. In genotype shift group, ADV treatment induced a marked enhancement of genotype B ratio accompanied by a reduction of genotype C ratio, suggesting genotype C may be more sensitive to ADV than genotype B. Moreover, patients with dominant genotype C may have a better therapeutic effect. Finally, genotype shifts was correlated with clinical improvement in terms of ALT.Conclusions
Our findings provided a rational explanation for genotype shift among ADV-treated CHB patients. The genotype and genotype shift might be associated with antiviral efficiency. 相似文献27.
Leukocyte cell surface sialyl Lewis x (sLex) and related epitopes play an important role in cell rolling and adhesion during diapedesis via interaction with E-selectin. Here, we present evidence that Mac-1 (CD11b/CD18, CR-3) is a major neutrophil glycoprotein decorated with sLex and ligation of these carbohydrate moieties by anti-sLex antibody significantly impairs neutrophil functions. First, Western blot analysis shows that both CD11b and CD18 subunit of purified Mac-1 are decorated with sLex moieties. A significant co-localization of CD11b and sLex moieties is observed at neutrophil secondary granules. With stimulation of formyl-Met-Leu-Phe (fMLP), neutrophil surface labeling with anti-sLex antibody follows an identical up-regulation pattern of Mac-1. Second, protein-binding assays indicate that sLex moieties on Mac-1 are critical for binding interaction of Mac-1 to E-selectin. Removal of sLex moieties completely abolishes Mac-1-E-selectin binding. Finally, ligation of Mac-1 sLex by anti-sLex antibody induces a significant degranulation of neutrophil secondary granules at the absence of chemoattractant stimulation. This “dysregulated” degranulation induced by anti-sLex antibody strongly inhibits neutrophil transmigration in response to fMLP. In summary, Mac-1 sLex moieties play a critical role in regulating β2 integrin functions during neutrophil transmigration and degranulation. 相似文献
28.
Neves FO Abreu PA Vasconcellos SA de Morais ZM Romero EC Nascimento AL 《Archives of microbiology》2007,188(5):523-532
This study examined four genes encoding for predicted membrane proteins selected from the genome sequences of Leptospira interrogans. Genes were cloned and the proteins expressed in E. coli. Immunoblotting analysis of the recombinants with sera from early and convalescent phases of a leptospirosis patient showed
that two proteins, namely Lp29 and Lp49, were reactive with serum from both phases of the illness. These data were further
confirmed in enzyme-linked immunosorbent assay using sera from both phases of seventeen confirmed leptospirosis specimens,
suggesting that these proteins are presented to the host immune system during infection. In the early phase, anti-Lp29 IgM
was detected in all sera when microscopic agglutination tests (MAT), the reference method for diagnosis of leptospirosis,
were negative. The gene encoding Lp49 is conserved among five tested leptospiral pathogenic serovars, while Lp29 is present
in serovars that are predominant in urban settings. These recombinant antigens might be valuable for serodiagnosis of both
phases of leptospirosis. 相似文献
29.