Application Of Mass Spectrometry In The Study Of Endometrial Biomarkers In Polycystic Ovary Syndrome

Objective:Polycystic ovary syndrome is a complex endocrine and metabolic disease,It has a variety of clinical manifestations,such as abnormal ovulation,infertility and high risk of pregnancy complications,the pathogenesis is not clear.Endometrium is closely related to pregnancy.The purpose of this study is to explore potential biomarkers of PCOS endometrium by mass spectrometry,and to integrate molecular information and cell function information through bioinformatics analysis,so as to provide clues for the study of the pathogenic mechanism of PCOS.Methods:The endometrial biopsy tissues of of infertile women with PCOS were taken as the samples,and the endometrial biopsy tissues of other infertile patients were taken as the control group,liquid chromatography-tandem mass spectrometry(LC-MS/MS)was used for proteomics studies to screen differentially expressed protein molecules.Through bioinformatics analysis,locate the biological pathways where differential proteins mainly play a role,so as to explain their correlation with PCOS disease performance.matrix-assisted laser desorption ionization mass spectrometry imaging(MALDI-MSI)was used to study small molecule metabolites,the distribution profiles of each molecule on tissue sections were obtained by mass spectrometry imaging,and the position information and abundance information of each small molecule were visually displayed.Results:In the proteomic study using LC-MS/MS technology,431 differentially expressed proteins were found in PCOS group,including 290 up-expressed proteins(FC FC≥2.0,P<0.05)and 141 down-expressed proteins(FC≤0.5,P<0.05).KEGG enrichment analysis of the differential proteins showed that tryptophan metabolism,tyrosine metabolism,ribosome biogenesis,phenylalanine metabolism,glycosaminoglycan biosynthesis-keratin sulfate,glycine serine and threonine metabolism,other types of O-glycan biosynthesis,retinol metabolism,neuroactive receptor-ligand interaction and other biological pathways were significantly enriched.An in-depth analysis of the tryptophan metabolic pathway revealed that two up-regulated proteins(amine oxidase[flavin-containing]A,amine oxidase[flavin-containing]B)and two down-regulated proteins(kynurenine-3-monooxygenase,HCG23341 protein)were involved in the tryptophan-kynurenine metabolic pathway.They may cause changes in the concentration of 3-hydroxy-L-kynurenine,L-kynurenine and their downstream metabolites Amine oxidase[flavin-containing]A and amine oxidase[flavin-containing]B also act on serotonin,a product of the tryptophan-serotonin metabolic pathway,catalyzing its degradation.In-depth analysis of the O-glycan chain synthesis process revealed that the differential protein beta-1,4-galactosyltransferase 1 was involved in the biosynthesis of O-fucose chains.The differential proteins glucoside xylosyltransferase 1 and glucoside xylosyltransferase 2 are involved in the biosynthesis of O-glucose chains.Abnormal O-glycan chain synthesis suggests that this reaction may affect the glycosylation of related proteins.In the study of small molecule metabolites(50-1000 m/z)by MALDI-MSI technology in the mode of reflecting positive ions,the molecular distribution on the mass spectrometry imaging maps of each molecule is relatively uniform,there is no tendency to aggregate,and the imaging results are clear.It suggests that the function of small molecule metabolites is dispersed.Through the preliminary analysis of the experimental results,it is found that there may be several differentially expressed molecules,which need further experimental verification.Conclusion:1)There are 431 differentially expressed proteins in PCOS endometrium,which can be used as target molecules to participate in the study of PCOS biomarkers and pathogenesis;2)PCOS endometrium may have abnormal tryptophan metabolism,O-glycan chain synthesis,and affect immune response,inflammatory response,cell proliferation and glycosylation through the production of downstream products;3)There may be alterations of small molecule metabolites in PCOS endometrium,MALDI-MSI can be used as a technical means to study small metabolite biomarkers in PCOS endometrium.