P-637 pseudo-targeted metabolomics of follicular fluid reveals ovarian GPD1L-mediated glycerophospholipid metabolism dysfunction in patients with biochemical premature ovarian insufficiency
Authors: Zhao X , Wu J , Tian Y , Wang J , Fang Y , Lan Y , Yang X , Xin Z 
Published: June 2023

Abstract

Study question
Does the metabolic profile of follicular fluid from patients with biochemical premature ovarian insufficiency (bPOI) differ from that of healthy women?

Summary answer
The metabolic signature of follicular fluid reveals a significant decrease of phosphatidic acid (PA), phosphatidylcholine (PC), lysophosphatidylcholine (lysoPC) and lysophosphatidylethanolamine (lysoPE) in bPOI patients.

What is known already
Metabolites in follicular fluid have attracted extensive attention as they are important components of the microenvironment during follicular development and oocyte maturation. Studies on follicular fluid metabolomics may enhance the understanding of the pathogenesis of ovarian aging, particularly premature ovarian insufficiency. Although a variety of metabolites have been suggested to be related to cell senescence, their specific roles in regulating follicular atresia remain unclear.

Study design, size, duration
An observational study of follicular fluid samples collected from 120 women undergoing in vitro fertilization and embryo transfer was conducted. All enrolled women were classified into two groups: one with 60 bPOI patients and the other with 60 healthy controls. Each group was further subdivided into two subgroups (young and aged group, 30 women for each section).

Participants/materials, setting, methods
The follicular fluids of mature follicles (diameter over 17 millimeters) were isolated and collected for pseudo-targeted metabolic analysis. The intensities of captured metabolites were utilized for further bioinformatic analysis. The correlation between the significant differential metabolites screened and their clinical outcomes were analyzed. In vitro experiments were used to demonstrate the cellular function of mainly regulated signaling pathway.

Main results and the role of chance
A total of 608 metabolites were identified in 120 follicular fluid samples. There were significant differences in 143 metabolites between the bPOI and healthy controls. As revealed by metabolic pathway analysis, glycerophospholipid metabolism was the most enriched pathway in bPOI follicular fluids. The intensities of several glycerophospholipid-associated metabolites PA, PC, lysoPC and lysoPE were positively correlated with the ovarian reserve indicator anti-Müllerian hormone (AMH), female age, as well as the expression level of glycerol-3-phosphatedehydrogenase 1-like (GPD1L), a key enzyme of this pathway, in granulosa cells. Furthermore, knockdown of GPD1L induced mitochondria dysfunction and granulosa cell apoptosis via GPD1L/PKCε/ATF2/NEAT1 pathway, as well as led to follicular atresia and impaired the quality of oocytes.

Limitations, reasons for caution
The validity of differential intensified metabolites we detected as biomarkers for clinical diagnosis needs to be confirmed in a large-scale study. And the multiple effects of glycerophospholipid metabolic pathway posed on follicular development need to be study in-depth.

Wider implications of the findings
Our results suggested that a highly coordinated follicular metabolism exhibits a strong relationship with the quality of follicles. An understanding of the mechanisms underlying ovarian aging will provide a theoretical basis, as well as new ideas for POI diagnosis, treatment and intervention.

Trial registration number
Not applicable.