Yunnan Province Key Laboratory for Porcine Gene Editing and Xenotransplantation, Yunnan Agricultural University, Kunming, China.
State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, China.
Biol Res. 2024 Sep 4;57(1):60. doi: 10.1186/s40659-024-00545-7.
Infertility is a growing global health concern affecting millions of couples worldwide. Among several factors, an extreme body weight adversely affects reproductive functions. Leptin is a well-known adipokine that serves as an endocrine signal between adiposity and fertility. However, the exact mechanisms underlying the effects of high leptin level on female reproduction remain unclear.
Transgenic pigs overexpressing leptin (♀) were produced by backcrossing and screened for leptin overexpression. The growth curve, fat deposition, reproductive performance, apoptosis, serum hormones and cholesterol production, RNA sequencing, and single-nucleus RNA sequencing (snRNA-seq) of the leptin-overexpressing pigs and wild-type group were evaluated.
Transgenic pigs overexpressing leptin (♀) were obtained, which exhibited significantly reduced body weight, body size, and back fat thickness. These pigs manifested a late onset of puberty (330 ± 54.3 vs. 155 ± 14.7 days), irregular estrous behavior characterized by increased inter-estrous interval (29.2 ± 0 vs. 21.3 ± 0.7 days), and more number of matings until pregnancy (at least 3 times). This reproductive impairment in leptin pigs was related to hormonal imbalances characterized by increased levels of FSH, LH, prolactin, E2, P4, and TSH, altered steroidogenesis such as increased levels of serum cholesterol esters along with steroidogenic markers (StAR, CYP19A), and ovarian dysfunctions manifested by neutrophilic infiltration and low expression of caspase-3 positive cells in the ovaries. Moreover, bulk RNA sequencing of the ovaries also revealed neutrophilic infiltration followed by upregulation of inflammation-related genes. Furthermore, snRNA-seq reflected that leptin overexpression triggered immune response, suppressed follicle development and luteinization, resulting in metabolic dysfunction and hormone imbalance in the ovary.
Low body weight in leptin overexpressing pigs adversely affects the reproductive performance, causing delayed puberty, irregular estrous cycles, and reduced breeding efficiency. This is linked to metabolic imbalances, an increased immune response, and altered ovarian functions. This study provides a theoretical basis for the complex mechanisms underlying leptin, and infertility by employing leptin-overexpressing female pigs.
不孕症是一个日益严重的全球健康问题，影响着全球数以百万计的夫妇。在诸多因素中，极度的体重会对生殖功能产生不利影响。瘦素是一种众所周知的脂肪细胞因子，它作为肥胖和生育能力之间的内分泌信号。然而，高瘦素水平对女性生殖的影响的确切机制尚不清楚。
通过回交和筛选瘦素过表达，生产出了过表达瘦素的转基因猪（♀）。评估了过表达瘦素的猪和野生型猪的生长曲线、脂肪沉积、繁殖性能、细胞凋亡、血清激素和胆固醇生成、RNA 测序和单核 RNA 测序（snRNA-seq）。
获得了过表达瘦素的转基因猪（♀），这些猪的体重、体型和背部脂肪厚度明显减少。这些猪的青春期开始时间较晚（330±54.3 天对 155±14.7 天），发情行为不规则，发情间隔增加（29.2±0 天对 21.3±0.7 天），配种次数更多才能怀孕（至少 3 次）。瘦素猪的这种生殖障碍与激素失衡有关，表现为 FSH、LH、催乳素、E2、P4 和 TSH 水平升高，胆固醇酯等类固醇生成改变，以及卵巢功能障碍，表现为中性粒细胞浸润和卵巢中 caspase-3 阳性细胞表达降低。此外，卵巢的 bulk RNA 测序也显示中性粒细胞浸润后炎症相关基因上调。此外，snRNA-seq 反映出瘦素过表达触发了免疫反应，抑制了卵泡发育和黄体化，导致卵巢代谢功能障碍和激素失衡。
瘦素过表达的猪体重过低会对生殖性能产生不利影响，导致青春期延迟、发情周期不规则和繁殖效率降低。这与代谢失衡、免疫反应增强和卵巢功能改变有关。本研究通过使用过表达瘦素的雌性猪，为瘦素和不孕症的复杂机制提供了理论依据。
