Department of Obstetrics and Gynecology, University of Kentucky College of Medicine, Lexington, KY 40536, USA.
Bluegrass Fertility Center, KY 40509, USA.
Endocrinology. 2021 Sep 1;162(9). doi: 10.1210/endocr/bqab127.
FOS, a subunit of the activator protein-1 (AP-1) transcription factor, has been implicated in various cellular changes. In the human ovary, the expression of FOS and its heterodimeric binding partners JUN, JUNB, and JUND increases in periovulatory follicles. However, the specific role of the FOS/AP-1 remains elusive. The present study determined the regulatory mechanisms driving the expression of FOS and its partners and functions of FOS using primary human granulosa/lutein cells (hGLCs). Human chorionic gonadotropin (hCG) induced a biphasic increase in the expression of FOS, peaking at 1 to 3 hours and 12 hours. The levels of JUN proteins were also increased by hCG, with varying expression patterns. Coimmunoprecipitation analyses revealed that FOS is present as heterodimers with all JUN proteins. hCG immediately activated protein kinase A and p42/44MAPK signaling pathways, and inhibitors for these pathways abolished hCG-induced increases in the levels of FOS, JUN, and JUNB. To identify the genes regulated by FOS, high-throughput RNA sequencing was performed using hGLC treated with hCG ± T-5224 (FOS inhibitor). Sequencing data analysis revealed that FOS inhibition affects the expression of numerous genes, including a cluster of genes involved in the periovulatory process such as matrix remodeling, prostaglandin synthesis, glycolysis, and cholesterol biosynthesis. Quantitative PCR analysis verified hCG-induced, T-5224-regulated expression of a selection of genes involved in these processes. Consistently, hCG-induced increases in metabolic activities and cholesterol levels were suppressed by T-5224. This study unveiled potential downstream target genes of and a role for the FOS/AP-1 complex in metabolic changes and cholesterol biosynthesis in granulosa/lutein cells of human periovulatory follicles.
fos，激活蛋白-1（ap-1）转录因子的一个亚基，与各种细胞变化有关。在人类卵巢中，fos 及其异二聚体结合伴侣 jun、junb 和 jund 的表达在排卵前卵泡中增加。然而，fos/ap-1 的具体作用仍不清楚。本研究利用原代人颗粒细胞/黄体细胞（hglc）确定了驱动 fos 及其伴侣表达的调节机制和 fos 的功能。人绒毛膜促性腺激素（hcg）诱导 fos 表达呈双相增加，峰值在 1 至 3 小时和 12 小时。hcg 也增加了 jun 蛋白的水平，其表达模式不同。共免疫沉淀分析表明，fos 与所有 jun 蛋白形成异二聚体。hcg 立即激活蛋白激酶 a 和 p42/44mapk 信号通路，这些通路的抑制剂消除了 hcg 诱导的 fos、jun 和 junb 水平增加。为了鉴定受 fos 调节的基因，用 hcg ± t-5224（fos 抑制剂）处理 hglc 后进行高通量 rna 测序。测序数据分析表明，fos 抑制影响许多基因的表达，包括涉及排卵过程的基因簇，如基质重塑、前列腺素合成、糖酵解和胆固醇生物合成。定量 pcr 分析验证了 hcg 诱导、t-5224 调节的这些过程中涉及的一些基因的表达。一致地，t-5224 抑制了 hcg 诱导的代谢活性和胆固醇水平的增加。本研究揭示了 fos/ap-1 复合物在人排卵前卵泡颗粒细胞/黄体细胞代谢变化和胆固醇生物合成中的潜在下游靶基因和作用。
