Using proteomics and single-cell sequencing to analyze the pathogenesis of recurrent implantation failure associated...

Recurrent implantation failure (RIF) affects about 10% of infertility patients and may involve mid-luteal phase endometrial natural killer (NK) cells. The pathogenesis of NK cells in RIF remains unclear.

Our study integrated proteomics data from endometrial tissues of six RIF patients and six controls, with single-cell sequencing insights.

Our proteomics analysis identified 1366 differentially expressed proteins (DEPs) between RIF and control groups, highlighting alterations in cellular processes, such as cytoplasmic translation and mRNA processing. Functional enrichment analysis revealed significant associations with pathways involved in amyotrophic lateral sclerosis and proteasomes. The DEPs were transformed into differentially expressed genes1 (DEGs1) by ID-transformation. 33 candidate genes were detected when ID-transformed 1210 DEGs1 were intersected with 752 DEGs2 from NK cells. After that, the proteomics sequencing data validation showed that the expression of AMPD3, H6PD, and PAK2 was consistent and significantly different from the GSE111974 dataset and classified as crucial genes. In addition, analysis of single-cell sequencing data annotated fibroblast-like stromal cells, NK cells, T cells, and endothelial cells, and these three essential genes showed that they were expressed in NK cells. Crossing the signaling pathways of key genes with those enriched for DEPs yielded the 'Escherichia coli infection' possibly associated with RIF. Finally, the transcription factor HR had a strong regulatory effect on the PAK2.

Finally, identifying three key genes (AMPD3, H6PD and PAK2) associated with RIF and the regulatory solid roles of HR and PAK2 provided a basis for understanding the molecular mechanism of RIF. Our findings may pave the way for developing targeted therapies to improve pregnancy outcomes in patients with RIF.