Systems-level proteomic profiling reveals modular control of human cervical remodeling during pregnancy†.

Cervical remodeling (CR) is essential for pregnancy maintenance and successful parturition, yet its molecular regulation in humans remains incompletely defined. This study aimed to present a high-resolution, longitudinal proteomic atlas of the human CR across normal gestation. A retrospective study was conducted using cervical tissue samples collected during nonpregnancy and at three trimesters. The study cohort included 10 healthy controls and 31 pregnant women with uncomplicated singleton pregnancies. Proteomic analyses were performed using data-independent acquisition mass spectrometry. Then, we carried out comparative proteomic analyses across adjacent gestational stages and unsupervised clustering of all quantified proteins based on their expression dynamics. Subsequently, we systematically characterized the dynamic regulation of collagen. Finally, protein-protein interaction networks based on temporally regulated proteins were constructed. We quantified 6092 proteins, revealing stage-specific shifts in immune regulation, extracellular matrix remodeling, and hormone responsiveness. Systematic evaluation of five canonical hypotheses for functional progesterone withdrawal identified receptor downregulation and hormone-binding protein sequestration as the dominant mechanisms within cervical tissue. Collagen composition and organization were progressively disrupted, accompanied by coordinated remodeling of hyaluronan, enzymatic expression levels, and elastic fiber components. Network-based analyses uncovered modular regulatory architectures and stage-specific rewiring of protein interactions. Finally, we infer fibronectin 1 (FN1), matrix-metalloproteases 9 (MMP9), and estrogen receptor 1 (ESR1) protein as central regulator molecules for CR. Our study provides a temporal framework to dissect stage-specific molecular events that drive CR. These findings establish a comprehensive proteomic framework for understanding human CR and highlight novel targets for predicting and modulating CR disorders.