Zhang Jing, Bai Hanako, Kawahara Manabu, Balboula Ahmed Z, Takahashi Masashi
Graduate School of Global Food Resources, Hokkaido University, Sapporo, Japan.
Research Faculty of Agriculture, Hokkaido University, Sapporo, Japan.
Cell Tissue Res. 2025 Jul 24. doi: 10.1007/s00441-025-03997-9.
The corpus luteum (CL) is an ovarian structure that secretes progesterone (P4) following ovulation, playing a crucial role in regulating the estrous cycle and maintaining pregnancy. Luteolysis, the structural and functional degradation of the CL, occurs through apoptosis and autophagy. Recent studies suggest that the circadian clock (CC) system, particularly the gene NR1D1, is involved in these processes. This study investigated the role of NR1D1 in bovine CL regression using an ex vivo model treated with prostaglandin F (PGF), the NR1D1 agonist GSK4112, and the antagonist SR8278. CL samples were classified into four estrous cycle stages based on ovarian morphology and analyzed for P4 secretion, as well as gene and protein expression related to steroid synthesis, the CC system, autophagy, and apoptosis. P4 levels, steroid synthesis-related genes, and CC system-related genes, including NR1D1, were highly expressed in the mid and late stages of the CL, whereas autophagy- and apoptosis-related genes peaked during regression. Western blotting and immunofluorescence revealed increased expression of NR1D1 and BMAL1 in the mid and late stages, while LC3 and CTSB were most prominent during regression. PGF treatment reduced NR1D1 and BMAL1 expression, along with decreased P4 levels and increased apoptosis markers. GSK4112 suppressed steroid synthesis while upregulating autophagy- and apoptosis-related genes. Conversely, SR8278 reversed PGF-induced luteal regression, restoring P4 and steroidogenic gene expression while suppressing CTSB. These findings suggest that NR1D1 interacts with PGF to regulate CL regression, highlighting the CC system as a potential target for improving reproductive efficiency in cattle.
黄体（CL）是一种卵巢结构，在排卵后分泌孕酮（P4），在调节发情周期和维持妊娠中起关键作用。黄体溶解，即CL的结构和功能退化，通过凋亡和自噬发生。最近的研究表明，生物钟（CC）系统，特别是基因NR1D1，参与了这些过程。本研究使用前列腺素F（PGF）、NR1D1激动剂GSK4112和拮抗剂SR8278处理的体外模型，研究了NR1D1在牛CL退化中的作用。根据卵巢形态将CL样本分为四个发情周期阶段，并分析P4分泌以及与类固醇合成、CC系统、自噬和凋亡相关的基因和蛋白质表达。P4水平、类固醇合成相关基因和CC系统相关基因，包括NR1D1，在CL的中期和后期高度表达，而自噬和凋亡相关基因在退化期间达到峰值。蛋白质免疫印迹和免疫荧光显示，NR1D1和BMAL1在中期和后期表达增加，而LC3和CTSB在退化期间最为突出。PGF处理降低了NR1D1和BMAL1的表达，同时P4水平降低，凋亡标志物增加。GSK4112抑制类固醇合成，同时上调自噬和凋亡相关基因。相反，SR8278逆转了PGF诱导的黄体退化，恢复了P4和类固醇生成基因的表达，同时抑制了CTSB。这些发现表明，NR1D1与PGF相互作用以调节CL退化，突出了CC系统作为提高牛繁殖效率的潜在靶点。
