Human endometrial proteins with cyclic changes in the expression during the normal menstrual cycle: characterization...

Area of Science:

• Proteomics
• Molecular Biology
• Gynecology

Background:

• The human endometrium undergoes dynamic changes throughout the menstrual cycle.
• Understanding the molecular basis of these cyclic changes is crucial for reproductive health.
• Previous studies have identified some, but not all, key proteins involved in endometrial cycling.

Purpose of the Study:

• To characterize 21 distinct endometrial proteins exhibiting cyclic expression patterns.
• To identify novel proteins associated with the proliferative and secretory phases of the menstrual cycle.
• To explore the potential of these proteins as biomarkers for specific endometrial phases.

Main Methods:

• Two-dimensional (2-D) electrophoresis was used to separate and visualize endometrial proteins.
• Proteins of interest were excised, concentrated using one-dimensional (1-D) SDS-polyacrylamide gel electrophoresis, and digested with trypsin.
• Tryptic fragments were analyzed using reverse-phase high-performance liquid chromatography (RP-HPLC) and partial amino-terminal sequencing.

Main Results:

• Identified cytoskeletal proteins (vimentins, keratin, tropomyosin, tubulin), proliferating cell nuclear antigen, and beta-galactoside binding lectin in the proliferative phase.
• Identified creatine kinase B, an isocitrate dehydrogenase-homologous protein, annexin IV precursor, 14-3-3 protein homologue (stratifin), and 21K tumor protein in the secretory phase.
• Two proteins remained unidentified, and four were present in insufficient quantities for characterization.

Conclusions:

• Most identified endometrial proteins show novel associations with menstrual cycle phases.
• These cycle-related proteins, particularly those identified in the proliferative and secretory phases, may serve as valuable clinical indicators.
• Further research could validate these proteins as biomarkers for assessing endometrial status.