Dysregulated landscape of RNA-binding proteins in unexplained recurrent spontaneous abortion revealed by bulk and single-cell transcriptome

In recurrent spontaneous abortion (RSA), impaired decidualization due to decidual stromal cell (DS) apoptosis or pyroptosis disrupts pregnancy maintenance. RNA-binding proteins (RBPs) are crucial regulators of gene expression in reproductive disorders. However, the comprehensive profile and dynamic role of RBPs in DS cells during RSA are not fully understood. In this study, single-cell transcriptome sequencing (scRNA-seq) data originated from six decidua tissues of RSA group and five health controls were downloaded and analyzed by differentially expressed genes (DEGs) analysis, pseudotime analysis, functional enrichment analysis, RBPs regulatory program analysis, transcription factor regulatory network analysis, correlation analysis and etc. We employed bulk RNA-seq data (including three RSA decidua tissues and three decidua in normal early pregnancy) to confirm the results from scRNA-seq data. DS cells were the most abundant population in decidua and the primary dysregulated type in RSA, showing a reduced proportion. DS harbored the most DEGs, enriched in post-transcriptional regulation. RBPs served as effective markers for cell annotation and reflected pathological states. Decorin (DCN) and lectin galactoside-binding soluble 3 (LGALS3) were upregulated, while ribosomal protein S17 (RPS17) was downregulated across various cells. The DS subclusters RBP-DS_0, 2, and 4 were diminished in RSA, with RBP-DS_2 nearly absent. Pseudotime analysis revealed an aberrant DS differentiation trajectory from State1 (pseudotime starting point) to State2 linked to abnormal progression in RSA. The expression of DCN, LGALS3, and solute carrier family 3 member 2 (SLC3A2) in DS subpopulations was significantly elevated in RSA and peaked in State2 along the pseudotime. This study explores RBPs for cell annotation and clustering in decidual tissue. Our findings implicated the regulatory role of RBPs in RSA pathogenesis and highlighted three key RBPs (DCN, LGALS3, and SLC3A2) whose upregulation in DS subclusters during the progression of RSA may be associated with aberrant differentiation, suggesting their potential as biomarkers and therapeutic targets.