ABSTRACT
B-cell activating factor (BAFF) from the TNF family is critical for B-cell survival and maturation. In this study, we identified a Yangtze alligator (Alligator sinensis, Alligatoridae) BAFF cDNA, designated as asBAFF, using reverse transcription polymerase chain reaction (RT-PCR) and rapid amplification of cDNA ends (RACE). The open reading frame of this cDNA encodes a 287-amino acid protein containing a predicted transmembrane domain and a furin protease cleavage site, similar to mammalian and avian BAFF. The amino acid identity between biologically soluble asBAFF (assBAFF) and csBAFF, hsBAFF, and msBAFF is 94, 76, and 71%, respectively. Real-time quantitative PCR analysis showed that the asBAFF gene is strongly expressed in the spleen. Since BAFF is always expressed as inclusion bodies in bacteria, it is difficult to purify. To enhance the soluble expression of assBAFF in Escherichia coli, we fused the extracellular region of the asBAFF gene to a small ubiquitin-related modifier gene (SUMO). Purified assBAFF was able to promote the survival of splenic lymphocytes and co-stimulate the proliferation of mouse B cells with anti-mouse IgM. These findings suggest that asBAFF plays an important role in the survival and proliferation of Yangtze alligator B cells, and because it is evolutionarily highly conserved, functional cross-reactivity exists between mammalian and Yangtze alligator BAFF.
Subject(s)
Alligators and Crocodiles/genetics , B-Cell Activating Factor/genetics , B-Cell Activating Factor/metabolism , Alligators and Crocodiles/classification , Amino Acid Sequence , Animals , B-Cell Activating Factor/chemistry , Base Sequence , Cell Proliferation/genetics , Escherichia coli/genetics , Gene Expression Regulation , Lymphocytes/cytology , Mice , Models, Molecular , Molecular Sequence Data , Open Reading Frames , Phylogeny , Protein Structure, Tertiary , Sequence Homology, Amino Acid , Spleen/cytologyABSTRACT
In clinical practice, we have found that cognitive impairment frequently occurs in chronic obstructive pulmonary disease (COPD) patients, but little is known about its pathophysiological mechanism. Given that brain-derived neurotrophic factor (BDNF) is affected by many factors such as smoking, infection, hypoperfusion and hypoxia, the present study was to explore the expression of BDNF in COPD rats. The rat COPD model was established by passive smoking and intratracheal instillation of lipopolysaccharide (LPS). Rats with the same age and gender ratios were divided into 4 groups: the control group (n = 6), the smoking group (n = 6), the LPS group (n = 6) and the smoking + LPS group (n = 6, COPD model). Level of BDNF in serum was measured by ELISA. And the expression of BDNF in the hippocampus was assessed using the immunohistochemistry and image analysis. The results showed that BDNF in the hippocampus and serum significantly increased in the smoking, LPS and smoking + LPS groups, compared to that in the control group. However, the expression of BDNF was less in the smoking + LPS group than that in the smoking or LPS group both in the hippocampus and serum. In conclusion, the expression of BDNF in the hippocampus and serum is highly increased in the COPD group. Smoking and intratracheal instillation of LPS induce the increase of BDNF level in the hippocampus and serum.
