Proteome Mapping of Cervical Mucus and Its Potential as a Source of Biomarkers in Female Tract Disorders

Abstract

Cervical mucus (CM) is a viscous fluid that is produced by the cervical glands and functions as a uterine cervix plug. Its viscosity decreases during ovulation, providing a window for non-invasive sampling. This study focuses on proteomic characterization of CM to evaluate its potential as a non-invasively acquired source of biomarkers and in understanding of molecular (patho)physiology of the female genital tract. The first objective of this work was to optimize experimental workflow for CM processing and the second was to assess differences in the proteomic composition of CM during natural ovulatory cycles obtained from intrauterine insemination (IUI) cycles and in vitro fertilization (IVF) cycles with controlled ovarian hyperstimulation. Proteomic analysis of CM samples revealed 4370 proteins involved in processes including neutrophil degranulation, cellular stress responses, and hemostasis. Differential expression analysis revealed 199 proteins enriched in IUI samples and 422 enriched in IVF. The proteins enriched in IUI were involved in phosphatidic acid synthesis, responses to external stimulus, and neutrophil degranulation, while those enriched in IVF samples were linked to neutrophil degranulation, formation of a cornified envelope and hemostasis. Subsequent analyses clarified the protein composition of the CM and how it is altered by hormonal stimulation of the uterus.

Uterine Fluid Extracellular Vesicles Proteome Is Altered During the Estrous Cycle

“…It is well established that that protein composition of UF is altered by hormonal stimulation in humans compared to the natural cycle ( 40 ). Interestingly, our comparison with natural cycle–obtained EVs versus hormonal synchronized cycle EVs proteome also indicate shift in protein enrichment.…”

Multidimensional screening for a multifunctional cervix: Examining cervical gland area at cervical length screening to predict spontaneous preterm birth.

“…This connection may be applicable across several disciplines of obstetrics and gynecology, such as for birth outcomes after infertility or oncologic care. For instance, cervical mucus collected from patients following intrauterine insemination or in vitro fertilization features unique proteome profiles 34 . The composition of cervical mucus has proven predictive of PTB when it features abnormal proportions of inflammatory mediators, such as in the presence of dysbiotic vaginal flora 35 .…”

Advances in mass spectrometry technologies to characterize cervicovaginal microbiome functions that impact spontaneous preterm birth

“…67,68 Since then, the depth, accuracy and dynamic range of MS platforms has greatly increased and one recent study was able to detect over four thousand (4370) vaginal proteins in the cervical mucus. 69 Although these advances in MS methodology have been accompanied by increases in computational capacity and expansion of databases for protein and metabolite identification, database limitations currently still restrict the number of identifications. 70 However, as these issues are addressed, the number of correct identifications has the potential to expand dramatically.…”

“…The human cervicovaginal proteome was first investigated in 2007 where 150 proteins were detected, including largely metabolic (32%) and immune response‐related (22%) proteins 67,68 . Since then, the depth, accuracy and dynamic range of MS platforms has greatly increased and one recent study was able to detect over four thousand (4370) vaginal proteins in the cervical mucus 69 . Although these advances in MS methodology have been accompanied by increases in computational capacity and expansion of databases for protein and metabolite identification, database limitations currently still restrict the number of identifications 70 .…”