Objective: To explore the dynamic transcriptional regulatory network of primordial follicle fate in obese mice to elucidate the potential mechanism of primordial follicle depletion.
Design: Experimental study and transcriptomic analysis.
Animals: Healthy (n=15) and obese (n=15) female mice.
Interventions: Six-week-old CD-1 mice were divided into healthy and high-fat diet groups and fed continuously for 12 weeks. The diet of healthy mice contained 10% fat. The diet of high-fat mice contained 60% fat.
Main outcome measures: Primordial to primary follicle transition rate, gene expression changes, enriched Kyoto Encyclopedia of Genes and Genomes pathways, and ferroptosis.
Results: Primordial follicle depletion was increased in the ovaries of obese mice. We found that deposited fat around primordial and primary follicles of obese mice was higher than that for healthy mice. The proliferation of granulosa cells around primary follicles was increased in obese mice. In addition, we uncovered specific gene signatures associated with the primordial to primary follicle transition (PPT) in obese mice using laser capture microdissection RNA sequencing analysis. Gene set enrichment analysis indicated that ferroptosis, cell oxidation, vascular endothelial growth factor, and mammalian target of rapamycin signaling were increased significantly in the primordial follicles of obese mice. Notably, the ferritin, acyl CoA synthetase long-chain family member 4, and solid carrier family 7 member 11 associated proteins of the ferroptosis signaling pathway were significantly increased in the PPT phase of obese mice.
Conclusion: Our work suggests that ferroptosis is a key pathway activated within immature ovarian follicles in the context of obesity and that the process may be involved in the physiological regulation of the PPT as well.
Keywords: Primordial follicle; RNA sequencing; depletion; laser capture microdissection; obese.
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