AUTHOR=Sun Ningyu , Chen Yuanyuan , Lu Lu , Yan Hua , Zhou Jing , Li Kai , Zhang Wuwen , Yuan Lihua , Heng Boon Chin , Zeng Weiwei , Shi Yin , Tong Guoqing , Yin Ping 

TITLE=Peptidomic analysis of follicular fluid in patients with polycystic ovarian syndrome

JOURNAL=Frontiers in Cell and Developmental Biology

VOLUME=11

YEAR=2023

URL=https://www.frontiersin.org/journals/cell-and-developmental-biology/articles/10.3389/fcell.2023.1289063

DOI=10.3389/fcell.2023.1289063

ISSN=2296-634X

ABSTRACT=<p><bold>Objective:</bold> The aim of this study was to analyze and compare the differential expression of peptides within the follicular fluid of polycystic ovary syndrome (PCOS) patients <italic>versus</italic> normal women by using peptidomics techniques. The underlying mechanisms involved in PCOS pathogenesis will be explored, together with screening and identification of potential functional peptides via bioinformatics analysis.</p><p><bold>Materials and methods:</bold> A total of 12 patients who underwent <italic>in vitro</italic> fertilization and embryo transfer (IVF-ET) at the Reproductive Medicine Center of Shuguang Hospital Affiliated to Shanghai University of Traditional Chinese Medicine from 1 September 2022 to 1 November 2022 were included in this study. The follicular fluid of PCOS patients (<italic>n</italic> = 6) and normal women (<italic>n</italic> = 6) were collected. The presence and concentration differences of various peptides were detected by the LC-MS/MS method. GO and KEGG analysis were performed on the precursor proteins of the differentially-expressed peptides, and protein network interaction analysis was carried out to identify functionally-relevant peptides among the various peptides.</p><p><bold>Results:</bold> A variety of peptides within the follicular fluid of PCOS <italic>versus</italic> normal patients were detected by peptidomics techniques. Altogether, 843 upregulated peptides and 236 downregulated peptides were detected (absolute fold change ≥2 and <italic>p</italic> &lt; 0.05). Of these, 718 (718 = 488 + 230) peptides were only detected in the PCOS group, while 205 (205 = 174 + 31) were only detected in the control group. Gene Ontology enrichment and pathway analysis were performed to characterize peptides through their precursor proteins. We identified 18 peptides from 7 precursor proteins associated with PCOS, and 4 peptide sequences were located in the functional domains of their corresponding precursor proteins.</p><p><bold>Conclusion:</bold> In this study, differences in the follicular development of PCOS <italic>versus</italic> normal patients were revealed from the polypeptidomics of follicular development, which thus provided new insights for future studies on the pathological mechanisms of PCOS development.</p>