Inflammatory Cytokine-Induced HIF-1 Activation Promotes Epithelial-Mesenchymal Transition in Endometrial Epithelial...

Area of Science:

• Reproductive Biology
• Cellular Biology
• Gynecology

Background:

• The endometrium experiences dynamic changes during the menstrual cycle, including oxygen fluctuations and inflammatory conditions.
• Chronic endometritis, characterized by persistent endometrial inflammation, is linked to implantation failure and miscarriage.
• Embryo implantation is hypothesized to involve epithelial-mesenchymal transition (EMT) in endometrial epithelial cells, but inflammation's role is unclear.

Purpose of the Study:

• To investigate how intrauterine oxygen levels, hypoxia-inducible factor (HIF), and inflammation affect endometrial epithelial cell differentiation and function.
• To elucidate the mechanisms by which inflammatory cytokines influence HIF activity and EMT in endometrial epithelial cells.

Main Methods:

• Utilized an immortalized human endometrial epithelial cell line (EM-E6/E7/TERT).
• Exposed cells to pro-inflammatory cytokines and lipopolysaccharide (LPS) under varying oxygen conditions.
• Assessed HIF-1α protein and mRNA levels, EMT marker expression, and cell migration.

Main Results:

• Pro-inflammatory cytokines significantly increased HIF-1α protein accumulation and mRNA levels.
• Inflammatory cytokines enhanced hypoxia-induced HIF-1α accumulation.
• Combined exposure to inflammatory cytokines and hypoxia upregulated EMT-inducing factors and increased cell migration.

Conclusions:

• Pro-inflammatory factors (cytokines, LPS) synergize with hypoxia to activate HIF-1 in endometrial epithelial cells.
• This synergistic activation promotes EMT, potentially contributing to implantation issues.
• Understanding these inflammatory pathways is crucial for addressing early pregnancy complications.