Impaired tight junction sealing and precocious involution in mammary glands of PKN1 transgenic mice
Impaired tight junction sealing and precocious involution in mammary glands of PKN1 transgenic mice
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DOI：
10.1242/jcs.03467
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发表时间：
2007-07-01
影响因子：
4
通讯作者：
Theuring, Franz
中科院分区：
文献类型：
--
作者：
Fischer, Andreas;Stuckas, Heiko;Theuring, Franz
乳腺经历一系列复杂的变化，以在分娩时产生大量的乳汁分泌。为了验证 Rho 通路信号传导在分泌激活中发挥作用的假设，我们制备了在乳腺上皮细胞中表达 Rho 效应蛋白 PKN1 组成型激活形式的转基因小鼠。 PKN1 激活对妊娠后期没有影响，但会抑制分娩后的乳汁分泌，从而降低转基因母鼠养育一窝幼仔的能力。乳腺形态以及细胞凋亡和 IFGBP5 和 TGF beta 3 表达的增加表明这些动物的性早熟。此外，导管内注射[C-14]蔗糖证明，转基因乳腺在分娩时的紧密连接密封受到损害。与这一发现一致，在表达组成型激活的 PKN1 的 EpH4 乳腺上皮细胞中，响应糖皮质激素刺激的紧密连接密封受到严重损害，而显性失活 PKN1 突变体的表达导致体外紧密连接密封加速。 occludin 和 ZO1 在顶端细胞边界的正确定位证明了紧密连接的形成没有受到损害。我们的结果证明 PKN1 通过干扰糖皮质激素信号传导参与乳腺紧密连接密封的调节。
The mammary gland undergoes a complex set of changes to establish copious milk secretion at parturition. To test the hypothesis that signaling through the Rho pathway plays a role in secretory activation, transgenic mice expressing a constitutively activated form of the Rho effector protein PKN1 in the mammary epithelium were generated. PKN1 activation had no effect in late pregnancy but inhibited milk secretion after parturition, diminishing the ability of transgenic dams to support a litter. Mammary gland morphology as well as increased apoptosis and expression of IFGBP5 and TGF beta 3 suggest precocious involution in these animals. Furthermore, tight junction sealing at parturition was impaired in transgenic mammary glands as demonstrated by intraductal injection of [C-14] sucrose. Consistent with this finding, tight junction sealing in response to glucocorticoid stimulation was highly impaired in EpH4 mammary epithelial cells expressing constitutively activated PKN1, whereas expression of a dominant-negative PKN1 mutant resulted in accelerated tight junction sealing in vitro. Tight junction formation was not impaired as demonstrated by the correct localization of occludin and ZO1 at the apical cell borders. Our results provide evidence that PKN1 participates in the regulation of tight junction sealing in the mammary gland by interfering with glucocorticoid signaling.