Robledo M M, Ursa M A, Sánchez-Madrid F, Teixidó J
Centro de Investigaciones Biológicas, Departamento de Immunología, Madrid, Spain.
Br J Haematol. 1998 Aug;102(3):804-11. doi: 10.1046/j.1365-2141.1998.00820.x.
Bone marrow stromal cells are required for sustained haemopoiesis. Transforming growth factor-beta (TGF-beta) is a multifunctional cytokine present in the bone marrow microenvironment which regulates the expression of several cytokines, cytokine receptors and cell adhesion elements. The TGF-beta receptors type I and II, and endoglin, mediate TGF-beta1 binding to the membrane of human bone marrow stromal cells. [125I]TGF-beta1-affinity labelling experiments showed that three different anti-endoglin monoclonal antibodies co-immunoprecipitated a 68 kD TGF-beta1-labelled polypeptide together with TGF-beta1/endoglin complexes. Here, we have shown that the 68 kD receptor corresponds to the type I receptor, indicating that endoglin and the type I receptor associate on the membrane of these cells upon ligand binding. The expression of endoglin by stromal cells was found to be up-regulated by TGF-beta1, but not by IL-1beta. The association of endoglin with signalling components of the TGF-beta receptor system on the membrane of bone marrow stromal cells might modulate TGF-beta1 access to the signalling pathways, and therefore it could regulate TGF-beta1-mediated stromal cellular responses.
持续造血需要骨髓基质细胞。转化生长因子-β（TGF-β）是存在于骨髓微环境中的一种多功能细胞因子，可调节多种细胞因子、细胞因子受体和细胞黏附分子的表达。I型和II型TGF-β受体以及内皮糖蛋白介导TGF-β1与人骨髓基质细胞膜的结合。[125I]TGF-β1亲和标记实验表明，三种不同的抗内皮糖蛋白单克隆抗体与TGF-β1/内皮糖蛋白复合物共同免疫沉淀出一种68kD的TGF-β1标记多肽。在此，我们已表明68kD受体对应于I型受体，这表明内皮糖蛋白和I型受体在配体结合后在这些细胞的膜上缔合。发现基质细胞中内皮糖蛋白的表达受TGF-β1上调，但不受IL-1β上调。内皮糖蛋白与骨髓基质细胞膜上TGF-β受体系统的信号成分的缔合可能会调节TGF-β1进入信号通路，因此它可以调节TGF-β1介导的基质细胞反应。
