Apoptosis in human endometrium: apoptotic detection methods and signaling

Area of Science:

• Reproductive Biology
• Cellular Biology
• Gynecology

Background:

• Apoptosis is recognized in the human endometrium during the late secretory and menstruating phases.
• The regulation of endometrial apoptosis during the menstrual cycle is not fully elucidated.

Purpose of the Study:

• To investigate the cyclic expression of Bcl-2, Sp-3, c-Jun, Fas, and Fas ligand in human endometrial glandular cells.
• To explore the potential roles of Sp-3 and c-Jun as transcriptional factors for Bcl-2.
• To understand the involvement of mitochondrial and death-receptor pathways in endometrial apoptosis.

Main Methods:

• Analysis of Bcl-2, Sp-3, c-Jun, Fas, and Fas ligand expression throughout the menstrual cycle.
• Assessment of caspase-3, -8, and -9 activities during different phases.
• Correlation of protein expression patterns with apoptotic events.

Main Results:

• Bcl-2 expression peaked in the late proliferative phase and decreased during the secretory phase, coinciding with increased apoptosis.
• Sp-3 and c-Jun expression patterns mirrored Bcl-2, suggesting their role in its transcription.
• Fas and Fas ligand were coexpressed throughout the cycle, with heightened Fas ligand expression in the secretory to menstruating phases.
• Caspase activities were elevated from the secretory to menstruating phases.

Conclusions:

• Bcl-2 transcription, potentially regulated by Sp-3 and c-Jun, is upregulated during the proliferative phase, inhibiting apoptosis.
• During the secretory phase, endometrial glandular cells undergo apoptosis through both death-receptor and mitochondrial pathways, indicated by decreased Bcl-2 and activated caspases.