Liu Ke, Wei Huimei, Nong Weihua, Peng Huo, Li Youzhu, Lei Xiaocan, Zhang Shun
Department of Reproductive Medical Center, The Affiliated Hospital of Guilin Medical University, Guilin, Guangxi, 541001, China; Clinical Anatomy & Reproductive Medicine Application Institute, Hengyang Medical College, University of South China, Hengyang Hunan, 421001, China.
Department of Reproductive Medical Center, The Affiliated Hospital of Guilin Medical University, Guilin, Guangxi, 541001, China; Gynecology Department, Maoming People's Hospital, Maoming, 525000, China.
Free Radic Biol Med. 2024 Nov 20;225:776-793. doi: 10.1016/j.freeradbiomed.2024.10.312. Epub 2024 Nov 1.
Decreased nicotinamide adenine dinucleotide (NAD) content has been shown to contribute to metabolic dysfunction during aging, including polycystic ovary syndrome (PCOS). However, the effect of NAD on ovulatory dysfunction in PCOS by regulating glycolysis has not been reported. Based on the observations of granulosa cells (GCs) transcriptome data from the Gene Expression Omnibus (GEO) database, the signal pathways including glycolysis and nicotinate-nicotinamide metabolism were significantly enriched, and most genes of the above pathway like LDHA and SIRT2 were down-regulated in PCOS patients. Therefore, the PCOS rat model was established by combining letrozole with a high-fat diet (HFD), we demonstrate that in vivo supplementation of nicotinamide mononucleotide (NMN) significantly improves the ovulatory dysfunction by facilitating the follicular development, promoting luteal formation, as well the fertility in PCOS rats. Furthermore, target energy metabolomics and transcriptome results showed that NMN supplementation ameliorates the lactate production by activating glycolytic process in the ovary. In vitro, when NAD synthesis and SIRT2 expression were inhibited, lactate content in KGN cells was decreased and LDHA expression was significantly inhibited. We confirmed that FK866 can enhance the acetylation of LDHA on 293T cells by Co-immunoprecipitation (Co-IP) assay. We also observed that inhibition of NAD synthesis can reduce the activity and increase the apoptosis of KGN cells. Overall, these benefits of NMN were elucidated and the Nampt/SIRT2/LDHA pathway mediated lactate production in granulosa cells played an important role in the improvement of follicular development disorders in PCOS. This study will provide experimental evidence for the clinical application of NMN in the treatment of PCOS in the future.
烟酰胺腺嘌呤二核苷酸（NAD）含量降低已被证明会导致衰老过程中的代谢功能障碍，包括多囊卵巢综合征（PCOS）。然而，NAD通过调节糖酵解对PCOS排卵功能障碍的影响尚未见报道。基于对基因表达综合数据库（GEO）中颗粒细胞（GCs）转录组数据的观察，包括糖酵解和烟酸 - 烟酰胺代谢在内的信号通路显著富集，且PCOS患者中上述通路的大多数基因如LDHA和SIRT2表达下调。因此，通过来曲唑与高脂饮食（HFD）联合建立PCOS大鼠模型，我们证明在体内补充烟酰胺单核苷酸（NMN）可通过促进卵泡发育、促进黄体形成以及提高PCOS大鼠的生育能力，显著改善排卵功能障碍。此外，靶向能量代谢组学和转录组结果表明，补充NMN可通过激活卵巢中的糖酵解过程来改善乳酸生成。在体外，当NAD合成和SIRT2表达受到抑制时，KGN细胞中的乳酸含量降低，LDHA表达显著受到抑制。我们通过免疫共沉淀（Co - IP）试验证实FK866可增强293T细胞上LDHA的乙酰化。我们还观察到抑制NAD合成可降低KGN细胞的活性并增加其凋亡。总体而言，阐明了NMN的这些益处，且颗粒细胞中Nampt/SIRT2/LDHA途径介导的乳酸生成在改善PCOS卵泡发育障碍中起重要作用。本研究将为未来NMN在PCOS治疗中的临床应用提供实验依据。
