Department of Biology, York University, 4700 Keele Street, Toronto, Ontario, Canada.
Mol Cell Proteomics. 2011 May;10(5):M110.004804. doi: 10.1074/mcp.M110.004804. Epub 2011 Feb 22.
Myogenesis is a well-characterized program of cellular differentiation that is exquisitely sensitive to the extracellular milieu. Systematic characterization of the myogenic secretome (i.e. the ensemble of secreted proteins) is, therefore, warranted for the identification of novel secretome components that regulate both the pluripotency of these progenitor mesenchymal cells, and also their commitment and passage through the differentiation program. Previously, we have successfully identified 26 secreted proteins in the mouse skeletal muscle cell line C2C12 (1). In an effort to attain a more comprehensive picture of the regulation of myogenesis by its extracellular milieu, quantitative profiling employing stable isotope labeling by amino acids in cell culture was implemented in conjunction with two parallel high throughput online reverse phase liquid chromatography-tandem mass spectrometry systems. In summary, 34 secreted proteins were quantified, 30 of which were shown to be differentially expressed during muscle development. Intriguingly, our analysis has revealed several novel up- and down-regulated secretome components that may have critical biological relevance for both the maintenance of pluripotency and the passage of cells through the differentiation program. In particular, the altered regulation of secretome components, including follistatin-like protein-1, osteoglycin, spondin-2, and cytokine-induced apoptosis inhibitor-1, along with constitutively expressed factors, such as fibulin-2, illustrate dynamic changes in the secretome that take place when differentiation to a specific lineage occurs.
成肌作用是一个特征明确的细胞分化程序，对外界环境非常敏感。因此，有必要对成肌分泌组（即分泌蛋白的集合）进行系统的特征描述，以鉴定调控这些多能前体细胞的全能性及其向分化程序的定向分化和通过的新型分泌组成分。此前，我们已经成功地鉴定了小鼠骨骼肌细胞系 C2C12 中的 26 种分泌蛋白（1）。为了更全面地了解细胞外环境对成肌作用的调控，我们采用了稳定同位素标记氨基酸在细胞培养中的定量分析方法，并结合了两个平行的高通量在线反相液相色谱-串联质谱系统。总的来说，我们定量了 34 种分泌蛋白，其中 30 种在肌肉发育过程中表现出差异表达。有趣的是，我们的分析揭示了几种新型的上调和下调的分泌组成分，它们可能对维持多能性和细胞通过分化程序具有重要的生物学意义。特别是，包括卵泡抑素样蛋白 1、骨桥蛋白、软骨素蛋白聚糖-2 和细胞因子诱导的凋亡抑制剂-1 在内的分泌组成分的调节变化，以及纤维蛋白-2 等组成型表达的因子，说明了当特定谱系发生分化时，分泌组会发生动态变化。
