Differential functions of calpain 1 during epithelial cell death and adipocyte differentiation in mammary gland involution
Differential functions of calpain 1 during epithelial cell death and adipocyte differentiation in mammary gland involution
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DOI：
10.1042/bj20130847
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发表时间：
2014-04-15
影响因子：
4.1
通讯作者：
Vina, Juan R.
中科院分区：
文献类型：
--
作者：
Arnandis, Teresa;Ferrer-Vicens, Ivan;Vina, Juan R.
钙蛋白酶在断奶早期在乳腺中被激活，切割主要位于细胞膜上的几种蛋白质，但也在其他细胞器如溶酶体、线粒体和细胞核中。通过免疫荧光和Western印迹分析，我们已经证明了calpain-1和calpain-2的核转位，以及在小叶肺泡室的上皮细胞中的几个细胞质核孔蛋白的裂解。在体内和体外钙蛋白酶抑制防止这种核孔蛋白降解。此外，钙蛋白酶-1也存在于非上皮乳腺组织细胞的细胞核中，伴随着脂肪细胞的再分化。钙蛋白酶-1被内化在细胞核内，并被发现存在于核染色质富集部分，与组蛋白H3相关。此外，我们已经证明，在体内和体外，组蛋白H3的N-末端残基的切割由钙蛋白酶-1。钙蛋白酶-1与H3 K4 me 3（在Lys处三甲基化的组蛋白H3（4））和H3 K27 me 3（在Lys处三甲基化的组蛋白H3（27））共定位于核周边，这是细胞分化所必需的二价表观遗传信号。使用ChIP检测，我们可以确认钙蛋白酶-1存在于脂肪组织中表达的关键基因的启动子中，如Cebpa（CCAAT/增强子结合蛋白α）和Lep（瘦素）。本研究的结果突出了钙蛋白酶-1在妊娠/哺乳周期后断奶腺体中的双重作用，控制程序性细胞死亡和参与脂肪细胞分化过程中的表观遗传程序。
Calpains become activated in the mammary gland early during weaning, cleaving several proteins located mainly in the cell membrane, but also in other organelles such as lysosomes, mitochondria and nuclei. By immunofluorescence and Western blot analysis, we have demonstrated the nuclear translocation of calpain-1 and calpain-2, together with the cleavage of several cytoplasmic nucleoporins in epithelial cells of the lobulo-alveolar compartment. In vivo and in vitro calpain inhibition prevented this nucleoporin degradation. In addition, calpain-1 was also present in the nucleus of non-epithelial mammary tissue cells, concomitant with adipocyte re-differentiation. Calpain-1 was internalized within nuclei and found to be present in the nuclear chromatin-enriched fraction, associated with histone H3. Furthermore, we have demonstrated, both in vivo and in vitro, the cleavage of the N-terminal residue of histone H3 by calpain-1. Calpain-1 co-localized with both H3K4me3 (histone H3 trimethylated at Lys(4)) and H3K27me3 (histone H3 trimethylated at Lys(27)) at the nuclear periphery, a bivalent epigenetic signal essential for cell differentiation. Using ChIP assays we could confirm the presence of calpain-1 in the promoters of key genes expressed in adipose tissue, such as Cebpa (CCAAT/enhancer-binding protein alpha) and Lep (leptin). The results of the present study highlight a dual role for calpain-1 in the weaned gland after the pregnancy/lactation cycle, controlling programmed cell death and participating in the epigenetic programme during adipocyte differentiation.