Department of Biotechnology, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 464-8603, Japan.
Cytotechnology. 2015 Aug;67(4):633-9. doi: 10.1007/s10616-014-9717-0. Epub 2014 Apr 9.
Interleukin-10 (IL-10) expression was significantly elevated upon stimulation with lipopolysaccharide (LPS) when the sialic acid-recognizing Ig-superfamily lectin Siglec-5 or -9 was overexpressed in RAW264 cells. During the course to clarify the mechanism for this activation, we found that IL-10 promoter proximal region up to -500 bp led to transactivation similar to that up to -1,500 bp. Among the transcription factors that activate the mouse IL-10 promoter so far reported, the level of C/EBPβ was increased in Siglec-9-expressing cells. Transient expression of the C/EBPβ major isoform LAP led to an increase in the expression of IL-10 in Siglec-9-expressing cells, but not in mock-transfected control RAW264 cells upon stimulation with LPS, as assessed by either a luciferase assay or the production of IL-10. Without LPS, the IL-10 promoter was activated by transiently expressed LAP in Siglec-9-expressing cells, however, the magnitude of transactivation was less than that with the LPS stimulation. The knockdown of C/EBPβ down-regulated the production of IL-10. Taken together, these results suggest that one of the reasons for the stimulation of IL-10 expression in Siglec-9-expressing cells may be an increase in intracellular C/EBPβ level.
当 RAW264 细胞中过度表达唾液酸识别 Ig 超家族凝集素 Siglec-5 或 Siglec-9 时，用脂多糖 (LPS) 刺激后白细胞介素 10 (IL-10) 的表达显著升高。在阐明这种激活机制的过程中，我们发现 IL-10 启动子近端区域高达 -500bp 导致与高达 -1500bp 的转录激活相似。迄今为止，在已报道的激活小鼠 IL-10 启动子的转录因子中，Siglec-9 表达细胞中 C/EBPβ 的水平增加。瞬时表达 C/EBPβ 主要同工型 LAP 导致 LPS 刺激时 Siglec-9 表达细胞中 IL-10 的表达增加，但在模拟转染对照 RAW264 细胞中则不然，如通过荧光素酶测定或 IL-10 的产生来评估。没有 LPS 时，IL-10 启动子在 Siglec-9 表达细胞中被瞬时表达的 LAP 激活，但转录激活的幅度小于 LPS 刺激。C/EBPβ 的敲低下调了 IL-10 的产生。综上所述，这些结果表明 Siglec-9 表达细胞中 IL-10 表达的刺激的一个原因可能是细胞内 C/EBPβ 水平的增加。
