In this paper we characterize the function of Xylosyltransferase 2 (XylT2) in different tissues to investigate the role XylT2 has in the proteoglycan (PG) biochemistry of multiple organs. The results show that in all organs examined there is a widespread and significant decrease in total XylT activity in Xylt2 knock out mice (Xylt2−/−). This decrease results in increased organ weight differences in lung, heart, and spleen. These findings, in addition to our previous findings of increased liver and kidney weight with loss of serum XylT activity, suggest systemic changes in organ function due to loss of XylT2 activity. The Xylt2−/− mice have splenomegaly due to enlargement of the red pulp area and enhanced pulmonary response to bacterial liposaccharide. Tissue glycosaminoglycan composition changes are also found. These results demonstrate a role of XylT2 activity in multiple organs and their PG content. Because the residual XylT activity in the Xylt2−/− is due to xylosyltransferase 1 (XylT1), these studies indicate that both XylT1 and XylT2 have important roles in PG biosynthesis and organ homeostasis.

在本文中，我们描述了木糖基转移酶 2 (XylT2) 在不同组织中的功能，以研究 XylT2 在多个器官的蛋白多糖 (PG) 生物化学中的作用。结果表明，在所有检查的器官中，Xylt2 敲除小鼠 (Xylt2-/-) 的总 XylT 活性普遍显着降低。这种减少导致肺、心脏和脾脏器官重量差异的增加。这些发现，除了我们之前发现的肝脏和肾脏重量随着血清 XylT 活性的丧失而增加之外，还表明由于 XylT2 活性的丧失导致器官功能的系统性变化。Xylt2 _-/- 小鼠由于红髓区域扩大和对细菌脂糖的肺反应增强而出现脾肿大。还发现了组织糖胺聚糖组成的变化。这些结果证明了 XylT2 活性在多个器官及其 PG 含量中的作用。由于 Xylt2-/- 中残留的 XylT 活性是由于木糖基转移酶 1 (XylT1)，这些研究表明 XylT1 和 XylT2 在 PG 生物合成和器官稳态中都具有重要作用。