TGF-β superfamily members modulate growth, branching, shaping, and patterning of the ureteric bud
TGF-β superfamily members modulate growth, branching, shaping, and patterning of the ureteric bud
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DOI：
10.1016/j.ydbio.2003.10.023
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发表时间：
2004-02-15
影响因子：
2.7
通讯作者：
Nigam, SK
中科院分区：
文献类型：
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作者：
Bush, KT;Sakurai, H;Nigam, SK
从后肾间充质(MM)来源的细胞分泌的条件培养液中分离出抑制输尿管芽(UB)生长的富含蛋白质的部分。洗脱图谱和免疫印迹显示存在转化生长因子-β超家族成员。用BMP2、BMP4、激活素或转化生长因子-β1处理培养的全胚胎肾脏，在肾脏的整体大小、UB分支的数量、分支的长度和角度以及UB茎的厚度方面都有统计学意义的差异。因此，输尿管树的模式被改变。然而，在器官培养中，LiF对整个胚胎肾脏的生长发育似乎只有微乎其微的影响。这些因素都以浓度依赖的方式直接抑制分离的UB的生长和分支，尽管程度不同。其中一些因子的拮抗剂降低了它们的抑制作用。对经转化生长因子-β1处理的UBS进行详细检查后，TUNEL染色显示TIPS中的细胞凋亡率仅略有增加，但整个过程中的增殖作用减弱。Ki67染色。这些数据表明，BMP2、BMP4、LIF、转化生长因子-β1和激活素(及其拮抗剂)对UB的生长和分支具有重要的直接调节作用，可能通过决定分支的数量以及分支发生的位置和方式来塑造不断增长的UB。为了支持这一概念，UBS在成纤维细胞生长因子7(FGF7)的存在下培养，它诱导形成球状结构，而茎和壶腹之间几乎没有区别[Mech.戴夫。109(2001)123]，以及转化生长因子-β超家族成员导致了瑞银的形成，茎和壶腹清晰。这表明，UB形态发生的正调节因子(即促进生长和分枝)和负调节因子(即抑制生长和抑制)可以协同作用形成细长的树枝状UB结构，类似于在完整发育的肾脏或全胚胎肾脏器官培养中观察到的结构。最后，纯化数据还表明，存在一种尚未鉴定的可溶性非肝素结合活性，可调节UB的生长和分支。这些数据表明，积极和消极的生长因子如何共同作用(可能是存在于间充质内的局部双极形态发生梯度)调节UB的矢状树枝模式，并在其发育过程中塑造分支，从而调节肾单位数量和小管/管口径。我们认为，在适当的基质环境中，当UB从快速分支阶段(由前馈机制控制)转变到分支减慢(负反馈)并最终停止时，转化生长因子-β类分子和其他非肝素结合抑制因子可以促进分支程序的“刹车”。(C)2003 Elsevier Inc.保留所有权利。
Protein-rich fractions inhibitory for isolated ureteric bud (UB) growth were separated from a conditioned medium secreted by cells derived from the metanephric mesenchyme (MM). Elution profiles and immunoblotting indicated the presence of members of the transforming growth factor-beta (TGF-beta) superfamily. Treatment of cultured whole embryonic kidney with BMP2, BMP4, activin, or TGF-beta1 leads to statistically significant differences in the overall size of the kidney, the number of UB branches, the length and angle of the branches, as well as in the thickness of the UB stalks. Thus, the pattern of the ureteric tree is altered. LIF, however, appeared to have only minimal effect on growth and development of the whole embryonic kidney in organ culture. The factors all directly inhibited, in a concentration-dependent fashion, the growth and branching of the isolated UB, albeit to different extents. Antagonists of some of these factors reduced their inhibitory effect. Detailed examination of TGF-beta1-treated UBs revedled only a slight increase in the amount of apoptosis in tips by TUNEL staining, but diminished proliferaltion throughout. by Ki67 staining. These data suggest an important direct modulatory role for BMP2, BMP4, LIF, TGF-beta1, and activin (as well as their antagonists) on growth and branching of the UB, possibly in shaping the growing UB by playing a role in determining the number of branches, as well as where and how the branches occur. In support of this notion, UBs cultured in the presence of fibroblast growth factor 7 (FGF7), which induces the formation of globular structures with little distinction between the stalk and ampullae [Mech. Dev. 109 (2001) 123], and TGF-beta superfamily members lead to the formation of UBs with clear stalks and ampullae. This indicates that positive (i.e., growth and branch promoting) and negative (i.e., growth and branch inhibiting) modulators of UB morphogenesis can cooperate in the formation of slender arborized UB structures similar to those observed in the intact developing kidney or in whole embryonic kidney organ culture. Finally, purification data also indicate the presence of an as yet unidentified soluble non-heparin-binding activity modulating UB growth and branching. The data suggest how contributions of positive and negative growth factors can together (perhaps as local bipolar morphogenetic gradients existing within the mesenchyme) modulate the vectoral arborization pattern of the UB and shape branches as they develop, thereby regulating both nephron number and tubule/duct caliber. We suggest that TGF-beta-like molecules and other non-heparin-binding inhibitory factors can, in the appropriate matrix context, facilitate "braking" of the branching program as the UB shifts from a rapid branching stage (governed by a feed-forward mechanism) to a stage where branching slows down (negative feedback) and eventually stops. (C) 2003 Elsevier Inc. All rights reserved.