Laboratory of Veterinary Biochemistry and Molecular Biology, College of Veterinary Medicine, Chungbuk National University, Cheongju, Chungbuk 361-763, Republic of Korea.
J Cell Biochem. 2012 Jan;113(1):194-203. doi: 10.1002/jcb.23344.
Calcium (Ca(2+)) is an important regulator of apoptotic signaling. Calbindin-D(9k) (CaBP-9k) and -D(28k) (CaBP-28k) have a high affinity for Ca(2+) ions. Uterine calbindins appear to be involved in the regulation of myometrial activity by intracellular Ca(2+). In addition, uterine calbindins are expressed in the mouse endometrium and are regulated by steroid hormones during implantation and development. The aim of the present study was to evaluate the regulation of apoptosis in the uteri of CaBP-9k, CaBP-28k, and CaBP-9k/28k knockout (KO) mice. Our findings indicated that Bax protein was enhanced in the uteri of CaBP-28k and CaBP-9k/28k KO mice compared to wild-type (WT) and CaBP-9k KO mice, but no difference was observed in Bcl-2 protein expression. The expressions of caspase 3, 6, and 7 proteins were higher in both CaBP-28k and CaBP-9k/28k KO mice than in WT and CaBP-9k KO mice. These results suggest that the absence of CaBP-28k increases apoptotic signaling. We also investigated the expression of endoplasmic reticulum (ER) stress genes by Western blot analysis in calbindin KO mice. C/EBP homologous protein and immunoglobulin heavy chain-binding protein protein levels were elevated in CaBP-28k KO mice compared to WT mice. When immature mice were treated with 17β-estradiol (E2) or progesterone (P4) for 3 days, we found that the expressions of Bax and caspase 3 protein were increased by E2 treatment in WT and CaBP-9k KO mice, and by P4 treatment in CaBP-28k KO mice. These results indicate that CaBP-28k blocks the up-regulation of apoptosis-related genes and ER stress genes, implying that CaBP-28k may decrease the expression of genes involved in apoptosis and ER stress in murine uterine tissue.
钙（Ca（2+））是凋亡信号的重要调节剂。钙结合蛋白-D（9k）（CaBP-9k）和-D（28k）（CaBP-28k）对 Ca（2+）离子具有高亲和力。子宫钙结合蛋白似乎参与了细胞内 Ca（2+）对子宫肌活动的调节。此外，子宫钙结合蛋白在小鼠子宫内膜中表达，并在着床和发育过程中受类固醇激素调节。本研究旨在评估 CaBP-9k、CaBP-28k 和 CaBP-9k/28k 敲除（KO）小鼠子宫中凋亡的调节。我们的研究结果表明，与野生型（WT）和 CaBP-9k KO 小鼠相比，CaBP-28k 和 CaBP-9k/28k KO 小鼠的 Bax 蛋白在子宫中增强，但 Bcl-2 蛋白表达无差异。在 CaBP-28k 和 CaBP-9k/28k KO 小鼠中，caspase 3、6 和 7 蛋白的表达均高于 WT 和 CaBP-9k KO 小鼠。这些结果表明，CaBP-28k 的缺失增加了凋亡信号。我们还通过 Western blot 分析研究了钙结合蛋白 KO 小鼠内质网（ER）应激基因的表达。与 WT 小鼠相比，CaBP-28k KO 小鼠中 C/EBP 同源蛋白和免疫球蛋白重链结合蛋白的水平升高。当未成熟小鼠用 17β-雌二醇（E2）或孕酮（P4）处理 3 天时，我们发现 E2 处理增加了 WT 和 CaBP-9k KO 小鼠中 Bax 和 caspase 3 蛋白的表达，而 P4 处理增加了 CaBP-28k KO 小鼠中 Bax 和 caspase 3 蛋白的表达。这些结果表明，CaBP-28k 阻断了与凋亡相关基因和 ER 应激基因的上调，这表明 CaBP-28k 可能降低了小鼠子宫组织中参与凋亡和 ER 应激的基因的表达。
