Cellular functions of a cytosolic glycerophosphocholine phosphodiesterase GDE5

我们之前已经证明GDE 5是一种胞浆甘油磷酸胆碱（GPC）磷酸二酯酶。在这里，我们的特点是细胞功能的GDE 5在脂肪细胞中，因为GDE 5的表达是高度表达在3 T3-L1脂肪细胞分化。在3 T3-L1脂肪细胞中内源性GDE 5的敲低通过调节有丝分裂克隆扩增而出乎意料地显著抑制脂肪细胞分化。降低GDE 5丰度导致细胞内GPC水平显著增加。我们发现，降低GDE 5表达显著上调3 T3-L1细胞中蛋白聚糖如光蛋白聚糖和核心蛋白聚糖的mRNA表达。这些结果表明，降低GDE 5丰度通过细胞内GPC积累引起渗透压失衡，并抑制脂肪细胞的有丝分裂克隆扩增。这些提供了一个新的角色GDE 5渗透平衡，这取决于GPC磷酸二酯酶活性的洞察。

We previously showed that GDE5 is a cytosolic glycerophosphocholine (GPC) phosphodiesterase. Here, we characterized the cellular functions of GDE5 in adipocytes because GDE5 expression is highly expressed during 3T3-L1 adipocyte differentiation. Knockdown of endogenous GDE5 in 3T3-L1 adipocytes dramatically suppressed adipocye differentiation, unexpectedly, through a modulation of the mitotic clonal expansion. Decreasing GDE5 abundance resulted in a marked increase in intracellular GPC level. We showed that decreasing GDE5 expression significantly upregulated mRNA expression of proteoglycans such as lumican, and decorin in 3T3-L1 cells. These results suggest that decreasing GDE5 abundance caused osmotic imbalance by the intracellular GPC accumulation and inhibited the mitotic clonal expansion of adipocytes. These provide an insight into the novel roles of GDE5 in osmotic balance which depends on GPC phosphodiesterase activity.