Metanephrogenic mesenchyme-to-epithelium transition induces profound expression changes of ion channels
Metanephrogenic mesenchyme-to-epithelium transition induces profound expression changes of ion channels
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DOI：
10.1152/ajprenal.2000.279.1.f65
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发表时间：
2000-07-01
影响因子：
4.2
通讯作者：
Horster, MF
中科院分区：
文献类型：
--
作者：
Huber, SM;Braun, GS;Horster, MF
指定上皮细胞类型的质膜转运蛋白的表达模式是在个体发生过程中获得的。为了研究后肾性间充质向上皮转化的过程，我们解剖了分支输尿管芽及其相邻的间充质囊胚（小鼠胚胎期E14）并将其移植到胶原基质上。在培养中，诱导的间充质细胞凝聚、聚集并转化为逗号形和s形体。在体外凝集过程中，转录因子Pax-2蛋白下调，上皮标志物E-cadherin和β -catenin蛋白上调。此外，Wilms肿瘤抑制蛋白WT-1在凝结时被检测到，并在S期下调，在S长臂中持续表达，膜片钳，将上皮前凝聚间充质细胞（n = 7）的全细胞电导（G，以nS/10 pF计）与管状近端S形体上皮（n = 6）进行比较。单细胞RT-PCR证实，这两个阶段均表达E-cadherin和WT-1 mRNA，进一步证实了所记录细胞的上皮和肾源性承诺。间充质细胞呈现全细胞电流（G = 6.7 +/- 1.3），反转电位（V-rev，单位mV）接近Cl- (E-Cl)平衡电位（V-rev = -40 +/- 7），提示Cl-电导分数较高。与之形成鲜明对比的是，s形体细胞（G = 4.0 +/- 1.1）电流的V-rev值为E-K (V-rev = -82 +/- 6)，表明其K+电导分数较高。此外，K+选择性全细胞尾电流分析和单通道记录显示K+通道表达的变化。此外，Kir6.1 K+通道mRNA和蛋白在两个阶段都下调，而K(v)LQT K+通道mRNA在整个阶段都丰富。总之，后肾性间质向上皮的转变伴随着质膜离子通道传导的深刻重组。
The expression patterns of plasma membrane transporters that specify the epithelial cell type are acquired with ontogeny. To study this process during metanephrogenic mesenchyme-to-epithelium transition, branching ureteric buds with their adjacent mesenchymal blastema (mouse embryonic day E14) were dissected and explanted on a collagen matrix. In culture, induced mesenchymal cells condensed, aggregated, and converted to the comma- and S-shaped body. During in vitro condensation and aggregation, transcription factor Pax-2 protein was downregulated while the epithelial markers E-cadherin and beta-catenin proteins were upregulated. In addition, Wilms' tumor suppressor protein WT-1 was detectable upon condensation and downregulated in the S stage, where expression persisted in the long arm of the S. Patch-clamp, whole cell conductance (G, in nS/10 pF) of preepithelial condensed mesenchymal cells (n = 7) was compared with that of tubular proximal S-shaped-body epithelium (n = 6). Both stages expressed E-cadherin and WT-1 mRNA, as demonstrated by single-cell RT-PCR, testifying further to the epithelial as well as the nephrogenic commitment of the recorded cells. Mesenchymal cells exhibited whole cell currents (G = 6.7 +/- 1.3) with reversal potentials (V-rev, in mV) near equilibrium potential for Cl- (E-Cl) (V-rev = -40 +/- 7) suggestive of a high fractional Cl- conductance. Currents of the S-shaped-body cells (G = 4.0 +/- 1.1), in sharp contrast, had a V-rev at E-K (V-rev = -82 +/- 6) indicating a high fractional K+ conductance. Further, analysis of K+-selective whole cell tail currents and single-channel recording revealed a change in K+ channel expression. Also, Kir6.1 K+ channel mRNA and protein were downregulated between both stages, whereas K(v)LQT K+ channel mRNA was abundant throughout. In conclusion, metanephrogenic mesenchyme-to-epithelium transition is accompanied by a profound reorganization of plasma membrane ion channel conductance.