Hu Longxiao, Li Dandan, Wei Qingqing, Kang Li, Sun Yi, Jiang Yunliang
College of Animal Science and Technology, Shandong Agricultural University, Taian 271017, China.
College of Animal Science and Technology, Shandong Agricultural University, Taian 271017, China; Shandong Provincial Key laboratory for Livestock Germplasm Innovation & Utilization, Shandong Agricultural University, Taian 271017, China.
Poult Sci. 2024 Dec;103(12):104501. doi: 10.1016/j.psj.2024.104501. Epub 2024 Nov 2.
Insulin-like growth factor binding protein-2 (IGFBP-2), a binding protein of insulin-like growth factor (IGF) system, regulates the activity of IGFs and also influences cellular function with endogenous activity. In mammals, IGFBP-2 is reported to affect ovarian follicle development and steroidogenesis; however, its role in the chicken ovary is unknown. In this study, we investigated the mRNA expression and function of a novel IGFBP-2 transcript and the effect of reproductive hormones and insulin-like growth factor 1 (IGF1) on its expression in the ovarian granulosa cells of chicken follicles. The mRNA expression of IGFBP-2 was significantly increased in granulosa cells after follicle selection and was higher in hierarchical granulosa cells (Post-GCs) than in pre-hierarchical granulosa cells (Pre-GCs). IGFBP-2 promoted the proliferation and inhibited the apoptosis of both Pre-GCs and Post-GCs, enhanced the mRNA expression of genes involved in progesterone (P4) synthesis in Pre-GCs. However, in Post-GCs, IGFBP-2 inhibited the mRNA expression of these genes and suppressed P4 secretion. The mRNA expression of IGFBP-2 was inhibited by estradiol (E2) and follicle-stimulating hormone (FSH), but enhanced by P4 in Pre-GCs. In Post-GCs, FSH and IGF1 stimulated the mRNA expression of IGFBP-2 synergistically. Knockdown of IGFBP-2 attenuated the stimulatory effect of IGF1 on the mRNA expression of the side chain cleavage enzyme cytochrome P450 family 11 subfamily A member 1 (CYP11A1). These findings indicate that IGFBP-2 is regulated by FSH and IGF1, exerts different functions in Pre-GCs and Post-GCs in regulating IGF1 and plays an important role in chicken follicle development by affecting granulosa cell proliferation and P4 synthesis.
胰岛素样生长因子结合蛋白2（IGFBP - 2）是胰岛素样生长因子（IGF）系统的一种结合蛋白，它调节IGF的活性，还以内源活性影响细胞功能。在哺乳动物中，据报道IGFBP - 2会影响卵巢卵泡发育和类固醇生成；然而，其在鸡卵巢中的作用尚不清楚。在本研究中，我们调查了一种新型IGFBP - 2转录本的mRNA表达和功能，以及生殖激素和胰岛素样生长因子1（IGF1）对其在鸡卵泡卵巢颗粒细胞中表达的影响。卵泡选择后，颗粒细胞中IGFBP - 2的mRNA表达显著增加，且在分级颗粒细胞（Post - GCs）中高于分级前颗粒细胞（Pre - GCs）。IGFBP - 2促进Pre - GCs和Post - GCs的增殖并抑制其凋亡，增强Pre - GCs中参与孕酮（P4）合成的基因的mRNA表达。然而，在Post - GCs中，IGFBP - 2抑制这些基因的mRNA表达并抑制P4分泌。在Pre - GCs中，雌二醇（E2）和促卵泡激素（FSH）抑制IGFBP - 2的mRNA表达，但P4增强其表达。在Post - GCs中，FSH和IGF1协同刺激IGFBP - 2的mRNA表达。敲低IGFBP - 2减弱了IGF1对侧链裂解酶细胞色素P450家族11亚家族A成员1（CYP11A1）mRNA表达的刺激作用。这些发现表明，IGFBP - 2受FSH和IGF1调节，在调节IGF1方面，在Pre - GCs和Post - GCs中发挥不同功能，并通过影响颗粒细胞增殖和P4合成在鸡卵泡发育中起重要作用。
