Vilariño-García Teresa, Pérez-Pérez Antonio, Santamaría-López Esther, Prados Nicolás, Fernández-Sánchez Manuel, Sánchez-Margalet Víctor
Department of Medical Biochemistry, Molecular Biology and Immunology. Medical School, Virgen Macarena University Hospital, University of Seville, Seville, Spain.
Valencian Infertility Institute (IVI), Seville, Spain.
Endocr Connect. 2020 Jun;9(6):479-488. doi: 10.1530/EC-20-0062.
Polycystic ovary syndrome (PCOS) is a complex metabolic disorder associated with ovulatory dysfunction, hyperandrogenism, obesity, and insulin resistance, that leads to subfertility. Sam68 is an RNA-binding protein with signaling functions that is ubiquitously expressed, including gonads. Sam68 is recruited to leptin signaling, mediating different leptin actions.
We aimed to investigate the role of Sam68 in leptin signaling, mediating the effect on aromatase expression in granulosa cells and the posible implication of Sam68 in the leptin resistance in PCOS.
Granulosa cells were from healthy donors (n = 25) and women with PCOS (n = 25), within the age range of 20 to 40 years, from Valencian Infertility Institute (IVI), Seville, Spain. Sam68 expression was inhibited by siRNA method and overexpressed by expression vector. Expression level was analysed by qPCR and immunoblot. Statistical significance was assessed by ANOVA followed by different post-hoc tests. A P value of <0.05 was considered statistically significant.
We have found that leptin stimulation increases phosphorylation and expression level of Sam68 and aromatase in granulosa cells from normal donors. Downregulation of Sam68 expression resulted in a lower activation of MAPK and PI3K pathways in response to leptin, whereas overexpression of Sam68 increased leptin stimulation of signaling, enhancing aromatase expression. Granulosa cells from women with PCOS presented lower expression of Sam68 and were resistant to the leptin effect on aromatase expression.
These results suggest the participation of Sam68 in leptin receptor signaling, mediating the leptin effect on aromatase expression in granulosa cells, and point to a new target in leptin resistance in PCOS.
多囊卵巢综合征（PCOS）是一种复杂的代谢紊乱疾病，与排卵功能障碍、高雄激素血症、肥胖和胰岛素抵抗相关，可导致生育力低下。Sam68是一种具有信号传导功能的RNA结合蛋白，在包括性腺在内的全身广泛表达。Sam68被募集到瘦素信号通路中，介导不同的瘦素作用。
我们旨在研究Sam68在瘦素信号通路中的作用，介导其对颗粒细胞中芳香化酶表达的影响，以及Sam68在PCOS瘦素抵抗中的可能作用。
颗粒细胞来自西班牙塞维利亚瓦伦西亚不孕症研究所（IVI）年龄在20至40岁之间的健康供体（n = 25）和PCOS女性（n = 25）。采用小干扰RNA（siRNA）方法抑制Sam68表达，并通过表达载体使其过表达。通过定量聚合酶链反应（qPCR）和免疫印迹分析表达水平。采用方差分析（ANOVA）及不同的事后检验评估统计学意义。P值<0.05被认为具有统计学意义。
我们发现瘦素刺激可增加正常供体颗粒细胞中Sam68和芳香化酶的磷酸化及表达水平。Sam68表达下调导致对瘦素反应时丝裂原活化蛋白激酶（MAPK）和磷脂酰肌醇-3激酶（PI3K）通路的激活降低，而Sam68过表达则增加瘦素对信号传导的刺激，增强芳香化酶表达。PCOS女性的颗粒细胞中Sam68表达较低，并且对瘦素对芳香化酶表达的作用具有抗性。
这些结果表明Sam68参与瘦素受体信号传导，介导瘦素对颗粒细胞中芳香化酶表达的作用，并指出了PCOS瘦素抵抗中的一个新靶点。
