Department of Clinical Laboratory, The Fourth Affiliated Hospital of Harbin Medical University, Harbin 150001, China.
J Cell Biochem. 2009 Dec 1;108(5):1076-83. doi: 10.1002/jcb.22336.
IL-13 is a central mediator of allergic inflammation and secreted by Th2 and bronchial smooth muscle cells (BSMC). However, little is known about the regulation of IL-13 secretion. To address it, a cDNA library of BSMC was screened for the proteins interacted with IL-13 by yeast two-hybridization. Besides IL-13 receptors, human sulfatase modifying factor 2 (SUMF2) was interacted with IL-13. Furthermore, SUMF2 and IL-13 were co-immunoprecipitated from BSMC, which was independent of IL-13 glycosylation. Interestingly, high levels of SUMF2 were expressed by BSMC, accompanied by significantly higher levels of intracellular IL-13, but lower levels of IL-13 secretion from BSMC. In contrast, little of SUMF2 was detected in lymphocytes, accompanied by lower levels of intracellular IL-13, but significantly higher levels of 12 kDa form of IL-13 secretion. Moreover, knockdown of SUMF2 expression by transfection with SUMF2-specific siRNA did not alter IL-13 mRNA transcription, but significantly reduced intracellular IL-13 levels, associated with increased levels of IL-13 secretion from BSMC. While induction of transient SUMF2 expression in lymphocytes failed to modulate IL-13 mRNA transcription. It significantly increased the contents of 12 kDa form of intracellular IL-13, accompanied by significantly reduced levels of IL-13 in their supernatants. In addition, blockage of N-glycosylation by treatment with tunicamycin eliminated 17 kDa form of intracellular IL-13, but failed to promote IL-13 secretion in BSMC. Collectively, our novel data clearly indicated that SUMF2 interacted with IL-13 and inhibited IL-13 secretion in BSMC and lymphocytes, which was independent of IL-13 glycosylation.
白细胞介素 13（IL-13）是过敏炎症的核心介质，由 Th2 和支气管平滑肌细胞（BSMC）分泌。然而，关于其分泌的调节知之甚少。为了解决这个问题，我们通过酵母双杂交筛选了 BSMC 的 cDNA 文库，以寻找与 IL-13 相互作用的蛋白质。除了 IL-13 受体，人类硫酸酯酶修饰因子 2（SUMF2）也与 IL-13 相互作用。此外，SUMF2 和 IL-13 从 BSMC 中共同免疫沉淀，这与 IL-13 的糖基化无关。有趣的是，BSMC 表达高水平的 SUMF2，同时细胞内 IL-13 水平显著升高，但从 BSMC 中分泌的 IL-13 水平较低。相比之下，淋巴细胞中检测到的 SUMF2 水平较低，同时细胞内 IL-13 水平较低，但 12 kDa 形式的 IL-13 分泌水平显著升高。此外，通过 SUMF2 特异性 siRNA 转染降低 SUMF2 表达不会改变 IL-13 mRNA 转录，但显著降低细胞内 IL-13 水平，与 BSMC 中 IL-13 分泌水平增加相关。而在淋巴细胞中诱导瞬时 SUMF2 表达未能调节 IL-13 mRNA 转录。它显著增加了细胞内 12 kDa 形式的 IL-13 含量，同时降低了其上清液中的 IL-13 水平。此外，用衣霉素处理阻断 N-糖基化消除了细胞内 17 kDa 形式的 IL-13，但未能促进 BSMC 中 IL-13 的分泌。总之，我们的新数据清楚地表明，SUMF2 与 IL-13 相互作用，并抑制 BSMC 和淋巴细胞中 IL-13 的分泌，这与 IL-13 的糖基化无关。
