Zernichow Lillian, Abrink Magnus, Hallgren Jenny, Grujic Mirjana, Pejler Gunnar, Kolset Svein O
Department of Nutrition, Institute of Basic Medical Sciences, University of Oslo, Box 1046 Blindern, 0316 Oslo, Norway.
J Biol Chem. 2006 Sep 15;281(37):26792-801. doi: 10.1074/jbc.M512889200. Epub 2006 Jun 28.
It has recently been shown that serglycin is essential for maturation of mast cell secretory granules. However, serglycin is expressed also by other cell types, and in this study we addressed the role of serglycin in macrophages. Adherent cells were prepared from murine peritoneal cell populations and from spleens, and analyzed for proteoglycan synthesis by biosynthetic labeling with [35S]sulfate. Conditioned media from serglycin-/- peritoneal macrophages and adherent spleen cells displayed a 65-80% reduction of 35S-labeled proteoglycans, compared with corresponding material from serglycin+/+ cells, indicating that serglycin is the dominant secretory proteoglycan in macrophages of these origins. In contrast, the levels of intracellular proteoglycans were similar in serglycin+/+ and serglycin-/- cells, suggesting that serglycin is not stored intracellularly to a major extent in macrophages. This is in contrast to mast cells, in which serglycin is predominantly stored intracellularly. Transmission electron microscopy revealed that the absence of serglycin did not cause any major morphological effects on peritoneal macrophages, in contrast to dramatic defects in intracellular storage vesicles in peritoneal mast cells. Several secretory products were not found to be affected by the lack of serglycin. However, the secretion of tumor necrosis factor-alpha in response to lipopolysaccharide stimulation was markedly higher in serglycin-/- cultures than in those of serglycin+/+. The present report thus demonstrates that serglycin is the major proteoglycan secreted by peritoneal macrophages and suggests that the macrophage serglycin may have a role in regulating secretion of tumor necrosis factor-alpha.
最近研究表明，丝甘蛋白聚糖对肥大细胞分泌颗粒的成熟至关重要。然而，其他细胞类型也表达丝甘蛋白聚糖，在本研究中，我们探讨了丝甘蛋白聚糖在巨噬细胞中的作用。从鼠腹膜细胞群体和脾脏中制备贴壁细胞，并用[35S]硫酸盐进行生物合成标记分析蛋白聚糖的合成。与丝甘蛋白聚糖+/+细胞的相应物质相比，来自丝甘蛋白聚糖-/-腹膜巨噬细胞和贴壁脾细胞的条件培养基中35S标记的蛋白聚糖减少了65 - 80%，这表明丝甘蛋白聚糖是这些来源巨噬细胞中的主要分泌蛋白聚糖。相反，丝甘蛋白聚糖+/+和丝甘蛋白聚糖-/-细胞内的蛋白聚糖水平相似，这表明丝甘蛋白聚糖在巨噬细胞中并非主要在细胞内储存。这与肥大细胞形成对比，在肥大细胞中丝甘蛋白聚糖主要在细胞内储存。透射电子显微镜显示，与腹膜肥大细胞内储存囊泡的显著缺陷相比，丝甘蛋白聚糖的缺失对腹膜巨噬细胞没有造成任何主要的形态学影响。未发现几种分泌产物受丝甘蛋白聚糖缺乏的影响。然而，在脂多糖刺激下，丝甘蛋白聚糖-/-培养物中肿瘤坏死因子-α的分泌明显高于丝甘蛋白聚糖+/+培养物。本报告因此证明丝甘蛋白聚糖是腹膜巨噬细胞分泌的主要蛋白聚糖，并表明巨噬细胞丝甘蛋白聚糖可能在调节肿瘤坏死因子-α的分泌中发挥作用。
