Wang Dan, Nie Huan, Ozhegov Evgeny, Wang Lin, Zhou Aimin, Li Yu, Sun Xue-Long
Department of Chemistry, Chemical and Biomedical Engineering and Center for Gene Regulation of Health and Disease (GRHD), Cleveland State University, 2121 Euclid Avenue, Cleveland, OH 44115, USA.
School of Life Science and Technology, Harbin Institute of Technology, Harbin, Heilongjiang 150000, People's Republic of China.
Glycobiology. 2015 Sep;25(9):1007-15. doi: 10.1093/glycob/cwv038. Epub 2015 Jun 1.
Sialic acids (SAs) are widely expressed on immune cells and their levels and linkages named as sialylation status vary upon cellular environment changes related to both physiological and pathological processes. In this study, we performed a global profiling of the sialylation status of macrophages and their release of SAs in the cell culture medium by using flow cytometry, confocal microscopy and liquid chromatography tandem mass spectrometry (LC-MS/MS). Both flow cytometry and confocal microscopy results showed that cell surface α-2,3-linked SAs were predominant in the normal culture condition and changed slightly upon treatment with atorvastatin for 24 h, whereas α-2,6-linked SAs were negligible in the normal culture condition but significantly increased after treatment. Meanwhile, the amount of total cellular SAs increased about three times (from 369 ± 29 to 1080 ± 50 ng/mL) upon treatment as determined by the LC-MS/MS method. On the other hand, there was no significant change for secreted free SAs and conjugated SAs in the medium. These results indicated that the cell surface α-2,6 sialylation status of macrophages changes distinctly upon atorvastatin stimulation, which may reflect on the biological functions of the cells.
唾液酸（SAs）在免疫细胞上广泛表达，其水平以及被称为唾液酸化状态的连接方式会随着与生理和病理过程相关的细胞环境变化而改变。在本研究中，我们通过流式细胞术、共聚焦显微镜和液相色谱串联质谱法（LC-MS/MS）对巨噬细胞的唾液酸化状态及其在细胞培养基中释放的SAs进行了全面分析。流式细胞术和共聚焦显微镜的结果均显示，在正常培养条件下，细胞表面α-2,3连接的SAs占主导，用阿托伐他汀处理24小时后变化不大，而α-2,6连接的SAs在正常培养条件下可忽略不计，但处理后显著增加。同时，通过LC-MS/MS方法测定，处理后细胞内总SAs的量增加了约三倍（从369±29增加到1080±50 ng/mL）。另一方面，培养基中分泌的游离SAs和结合SAs没有显著变化。这些结果表明，巨噬细胞的细胞表面α-2,6唾液酸化状态在阿托伐他汀刺激后发生明显变化，这可能反映在细胞的生物学功能上。
