Non-canonical progesterone signaling in granulosa cell function

Area of Science:

• Reproductive Biology
• Endocrinology
• Cell Biology

Background:

• Progesterone (P4) is known to suppress ovarian follicle growth.
• The classic nuclear progesterone receptor (PGR) is not expressed in granulosa cells of developing follicles.
• Alternative P4 binding proteins, like PGRMC1, are present in these cells.

Purpose of the Study:

• To investigate the role of PGRMC1 as a functional receptor for progesterone in ovarian granulosa cells.
• To determine if PGRMC1 mediates P4's effects on granulosa cell mitosis and apoptosis.
• To explore the clinical relevance of PGRMC1 in reproductive disorders.

Main Methods:

• Assessing P4 binding and functional effects in granulosa cells with varying PGRMC1 expression.
• Utilizing PGRMC1-depleted cell models to evaluate P4-dependent cellular responses.
• Generating genetically modified mice with conditional PGRMC1 depletion in granulosa cells.
• Analyzing the impact of PGRMC1 on gene expression and T-cell-specific transcription factor pathways.

Main Results:

• PGRMC1 binds P4 with high affinity and mediates P4's anti-mitotic and anti-apoptotic actions in granulosa cells.
• PGRMC1 depletion abrogates P4's effects on granulosa cell proliferation and survival.
• Conditional depletion of PGRMC1 in mouse granulosa cells impairs follicle development.
• Altered PGRMC1 expression is linked to infertility, premature ovarian failure, and PCOS.

Conclusions:

• PGRMC1 functions as a key receptor for progesterone in ovarian granulosa cells.
• PGRMC1 mediates P4's regulation of granulosa cell proliferation, survival, and follicle development.
• Dysregulation of PGRMC1 is implicated in various human reproductive pathologies.