Hypoxia and PGE(2) regulate MiTF-CX during cervical ripening.

Area of Science:

• Reproductive biology
• Molecular endocrinology
• Cellular signaling

Background:

• Cervical closure mechanisms during pregnancy are poorly understood.
• Interleukin-8 (IL-8) is implicated in cervical remodeling and labor.
• IL-8 gene expression is transcriptionally repressed by microphthalmia-associated transcription factor (MiTF-CX) in the pregnant cervix.

Purpose of the Study:

• To investigate the role of hypoxia and hypoxia-inducible factor-1α (HIF-1α) in regulating MiTF-CX and cervical ripening.
• To elucidate the molecular pathways linking hypoxia to cervical changes during pregnancy.

Main Methods:

• Analysis of human cervical tissues from pregnant women before and after cervical ripening.
• Investigation of hypoxia and hypoxia mimetics effects on gene expression and protein localization.
• Assessment of differentiated embryo chondrocyte-expressed gene 1 (DEGs1) binding to the MiTF-CX promoter.
• Evaluation of ectopic MiTF-CX overexpression effects on IL-8 expression.
• Analysis of cyclooxygenase-2 (COX-2) and prostaglandin E(2) (PGE2) roles.

Main Results:

• HIF-1α stabilization and nuclear translocation observed during cervical ripening.
• Hypoxia and hypoxia mimetics induced DEGs1, which repressed MiTF-CX.
• Ectopic MiTF-CX abrogated hypoxia-induced IL-8 upregulation.
• HIF-1α activation led to COX-2 induction and PGE2-mediated repression of MiTF-CX.

Conclusions:

• Hypoxia and HIF-1α stabilization drive cervical ripening by upregulating DEGs1, causing MiTF-CX loss and IL-8 expression.
• Hypoxia also induces COX-2, leading to PGE2-mediated MiTF-CX downregulation in cervical stromal cells.
• These findings highlight a critical role for hypoxia and HIF-1α in the physiological process of cervical ripening during pregnancy.