Prante Christian, Kuhn Joachim, Kleesiek Knut, Götting Christian
Institut für Laboratoriums- und Transfusionsmedizin, Herz- und Diabeteszentrum NRW, Universitätsklinik der Ruhr-Universität Bochum, Bad Oeynhausen, Germany.
Glycoconj J. 2009 Feb;26(2):219-27. doi: 10.1007/s10719-008-9180-2. Epub 2008 Sep 2.
Skeletal growth and tissue remodelling processes are characterized by an elevated collagen and proteoglycan biosynthesis. The xylosyltransferases I and II are the rate-limiting step enzymes in proteoglycan biosynthesis and serum xylosyltransferase (XT) activity has been shown to be a biomarker for the actual proteoglycan biosynthesis rate. Here, XT, alkaline phosphatase (ALP), bone ALP (BALP) activities were measured in 133 juvenile Caucasians. Serum XT activities in juveniles were elevated and significantly correlated with ALP and BALP. In an osteoblast-like cell model using SAOS-2 cells mineralization and bone nodule formation were induced and XT-I, XT-II and ALP were monitored. Induction of mineralization in SAOS-2 cells resulted in a long-term increase of XT-I mRNA and enzyme activity, which could be paralleled with elevated ALP activity. In addition, HGH and IGF-I treatment of SAOS-2 cells led to an increased expression of XT-I and ALP. These results point to skeletal growth and tissue remodeling as a cause of the high XT activity in children.
骨骼生长和组织重塑过程的特点是胶原蛋白和蛋白聚糖生物合成增加。木糖基转移酶I和II是蛋白聚糖生物合成中的限速酶，血清木糖基转移酶（XT）活性已被证明是实际蛋白聚糖生物合成速率的生物标志物。在此，对133名高加索青少年的XT、碱性磷酸酶（ALP）、骨碱性磷酸酶（BALP）活性进行了测量。青少年的血清XT活性升高，且与ALP和BALP显著相关。在使用SAOS-2细胞的成骨细胞样细胞模型中，诱导矿化和骨结节形成，并监测XT-I、XT-II和ALP。SAOS-2细胞矿化诱导导致XT-I mRNA和酶活性长期增加，这与ALP活性升高平行。此外，用生长激素（HGH）和胰岛素样生长因子-I（IGF-I）处理SAOS-2细胞导致XT-I和ALP表达增加。这些结果表明，骨骼生长和组织重塑是儿童XT活性高的原因。
