2. Academic Validation
  3. Abnormal cholesterol-cholesteryl ester metabolism impairs mouse oocyte quality during ovarian aging

Abnormal cholesterol-cholesteryl ester metabolism impairs mouse oocyte quality during ovarian aging

  • Cell Mol Biol Lett. 2025 Nov 24;30(1):140. doi: 10.1186/s11658-025-00811-w.
Sainan Zhang 1 2,  Bichun Guo 3,  Junshun Fang 3,  Shanshan Wang 3,  Yicen Liu 4,  Die Wu 3,  Nannan Kang 3,  Yang Zhang 3,  Xin Zhen 3,  Guijun Yan 3,  Lijun Ding 5 6 7 8 9 10 11,  Haixiang Sun 12 13 14,  Chuanming Liu 15 16
Affiliations

Affiliations

  • 1 Center for Reproductive Medicine and Obstetrics and Gynecology, Nanjing Drum Tower Hospital Clinical College of Nanjing Medical University, Nanjing, China.
  • 2 State Key Laboratory of Reproductive Medicine and Offspring Health, Nanjing Medical University, Nanjing, China.
  • 3 Center for Reproductive Medicine and Obstetrics and Gynecology, Nanjing Drum Tower Hospital, Affiliated Hospital of Medical School, Nanjing University, Nanjing, China.
  • 4 Center for Reproductive Medicine and Obstetrics and Gynecology, Joint Institute of Nanjing Drum Tower Hospital for Life and Health, College of Life Science, Nanjing Normal University, Nanjing, China.
  • 5 Center for Reproductive Medicine and Obstetrics and Gynecology, Nanjing Drum Tower Hospital Clinical College of Nanjing Medical University, Nanjing, China. [email protected].
  • 6 State Key Laboratory of Reproductive Medicine and Offspring Health, Nanjing Medical University, Nanjing, China. [email protected].
  • 7 Center for Reproductive Medicine and Obstetrics and Gynecology, Nanjing Drum Tower Hospital, Affiliated Hospital of Medical School, Nanjing University, Nanjing, China. [email protected].
  • 8 Center for Reproductive Medicine and Obstetrics and Gynecology, Joint Institute of Nanjing Drum Tower Hospital for Life and Health, College of Life Science, Nanjing Normal University, Nanjing, China. [email protected].
  • 9 Center for Molecular Reproductive Medicine, Nanjing University, Nanjing, China. [email protected].
  • 10 State Key Laboratory of Analytic Chemistry for Life Science, Nanjing University, Nanjing, China. [email protected].
  • 11 Clinical Center for Stem Cell Research, Nanjing Drum Tower Hospital, Nanjing University, Nanjing, China. [email protected].
  • 12 Center for Reproductive Medicine and Obstetrics and Gynecology, Nanjing Drum Tower Hospital Clinical College of Nanjing Medical University, Nanjing, China. [email protected].
  • 13 State Key Laboratory of Reproductive Medicine and Offspring Health, Nanjing Medical University, Nanjing, China. [email protected].
  • 14 Center for Reproductive Medicine and Obstetrics and Gynecology, Nanjing Drum Tower Hospital, Affiliated Hospital of Medical School, Nanjing University, Nanjing, China. [email protected].
  • 15 Center for Reproductive Medicine and Obstetrics and Gynecology, Nanjing Drum Tower Hospital Clinical College of Nanjing Medical University, Nanjing, China. [email protected].
  • 16 Center for Reproductive Medicine and Obstetrics and Gynecology, Nanjing Drum Tower Hospital, Affiliated Hospital of Medical School, Nanjing University, Nanjing, China. [email protected].
PMID: 41286604 DOI: 10.1186/s11658-025-00811-w
Abstract

Background: Ovarian aging-induced decline in oocyte quality has been a main issue in women of advanced maternal age. However, the potential mechanism remains elusive, and there are no effective strategies to ameliorate aged oocyte quality. The lipid metabolism of oocytes has drawn great attention, but the intrinsic regulation of oocyte quality by metabolites, metabolic Enzymes, and intracellular mediators is less well-characterized.

Methods: Targeted lipidomics was employed to detect the neutral lipids in oocytes during maturation. We used 4,4-difluoro-1,3,5,7,8-pentamethyl-4-bora-3a,4a-diaza-s-indacene (BODIPY 493/503) and Filipin to stain cholesteryl ester and free Cholesterol, respectively. The Cholesterol/Cholesteryl Ester Quantification Assay kit was used further to quantify cholesterol-related metabolites. Western blotting was performed to evaluate acyl-coenzyme A: cholesterol Acyltransferase 1/2 (ACAT1/2) expression. Immunofluorescence and quantitative real-time polymerase chain reaction (qRT-PCR) were conducted to validate the knockdown efficiency of ACAT1. Avasimibe treatment and ACAT1 small interfering RNA (siRNA) microinjection were performed to investigate the effect of impaired cholesterol-cholesteryl ester metabolism on oocyte quality. Single-oocyte RNA Sequencing was conducted to explore the mechanism. Mitochondrial membrane potential (MMP), adenosine triphosphate (ATP) production, Reactive Oxygen Species (ROS), and mitochondrial autophagosomes were detected to evaluate mitochondrial function and Mitophagy.

Results: There is a profound increase in the conversion of Cholesterol to cholesteryl ester in oocytes during maturation, which depends on ACAT1. Conversely, disturbing the homeostasis of cholesterol-cholesteryl ester metabolism by manipulating ACAT1 impairs oocyte quality, primarily manifested as decreased polar body extrusion (PBE), increased meiotic defects, and abnormal early embryonic development. Mechanistically, the impaired conversion of Cholesterol to cholesteryl ester reduces oocyte Mitophagy, leading to mitochondrial dysfunction, including reduced MMP and ATP production, and excessive accumulation of ROS. Notably, we also reveal that this metabolic homeostasis is impaired in aged oocytes, accompanied by decreased ACAT1 levels. Moreover, cholesteryl ester supplementation via Cholesterol conjugated to methyl-β-cyclodextrin (CCM) can effectively ameliorate aged oocyte quality by enhancing Mitophagy.

Conclusions: This study reveals the mechanism by which cholesterol-cholesteryl ester metabolism regulates oocyte quality and thus participates in the process of oocyte aging by influencing Mitophagy and mitochondrial function.

Keywords

ACAT1; Cholesterol–cholesteryl ester metabolism; Mitochondrial function; Mitophagy; Oocyte aging; Oocyte maturation.

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