Laminin-dependent integrin beta 1 signaling regulates milk protein synthesis via prolactin/STAT5 pathway in bovine mammary epithelial cells
Laminin-dependent integrin beta 1 signaling regulates milk protein synthesis via prolactin/STAT5 pathway in bovine mammary epithelial cells
复制标题
层粘连蛋白依赖性整合素β1信号通过催乳素/STAT5途径调节牛乳腺上皮细胞乳蛋白合成
DOI：
10.1016/j.bbrc.2020.01.086
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发表时间：
2020
影响因子：
3.1
通讯作者：
Zhao Feng
中科院分区：
文献类型：
--
作者：
Wang Baosheng;Men Jingjing;Wang Chunmei;Hou Xiaoming;Zhao Feng
乳蛋白合成的成功诱导依赖于催乳素/STAT5。在小鼠中，层粘连蛋白和β1整合素都是催乳素诱导的STAT5活性所必需的，从而导致β酪蛋白的转录激活。然而，β-1整合素促进牛乳蛋白质合成的机制尚不清楚。为了揭示整合素信号和产乳信号之间的相互作用，我们研究了层粘连蛋白通过与β1整合素相互作用在牛乳腺上皮细胞上介导生乳作用的机制。因此，用免疫荧光法检测了β-1整合素的定位。用实时定量聚合酶链式反应和蛋白印迹法检测细胞的mRNA和蛋白表达水平。结果表明，在贴壁的BMEC基底膜和基底膜表面均可检测到β1整合素的表达。然而，在没有层粘连蛋白激活的情况下，β1整合素的基础分布不足以增加β-酪蛋白的合成。胰岛素、氢化可的松和催乳素组成的促乳素激素组合刺激了整体的生乳效应，包括上调β1整合素的表达，激活催乳素/STAT5信号，从而增加β-酪蛋白的合成。在24小时催乳素作用下，含层粘连蛋白的BMEC中STAT5、β-1整合素和β-酪蛋白的丰度高于对照组。同时，通过阻断β-1整合素功能，抑制层粘连蛋白依赖的产乳作用，导致STAT5活性减弱，β-酪蛋白合成减少。这些结果表明，β-1整合素是层粘连蛋白依赖的催乳素/STAT5信号转导的关键介质，该信号转导调节β-酪蛋白表达所必需的STAT5活性。
Successful induction of milk protein synthesis relies on prolactin/STAT5. In mice, both laminin and β1 integrin were necessary for STAT5 activity induced by prolactin treatment, resulting in transcriptional activation of β-casein. However, the mechanism by which β1 integrin increases the bovine milk protein synthesis is not well known. In order to display the crosstalk between integrin signaling and lactogenic signaling, we investigated the mechanism by which laminin mediated lactogenic effects via interaction with β1 integrin on bovine mammary epithelial cells (BMECs). Therefore, localization of β1 integrin was examined by immunofluorescence. The mRNA and protein expression levels were determined by quantitative real-time PCR and western blotting. The results showed that β1 integrin were detected in basal mammary cells and basal membrane surface of adherent BMECs. However, basal distribution of β1 integrin was not sufficient to increase β-casein synthesis in the absence of integrin activation by laminin. A lactogenic hormone cocktail of insulin, hydrocortisone, and prolactin stimulated overall lactogenic effects, including upregulated expression of β1 integrin, activation of prolactin/STAT5 signaling, and consequent increase of β-casein synthesis. In response to a 24 h prolactin treatment, the abundance of STAT5, β1 integrin, and β-casein in BMECs with laminin was higher compared to that with a control substratum. Meanwhile, laminin-dependent lactogenic effects were inhibited by blocking β1 integrin function, resulting in attenuated STAT5 activity and decreased β-casein synthesis. These results indicated that β1 integrin was a key mediator of the laminin-dependent prolactin/STAT5 signaling, which regulated the sustained STAT5 activity necessary for β-casein expression in BMECs.