Hypothalamic EAP1 (enhanced at puberty 1) is required for menstrual cyclicity in nonhuman primates

Area of Science:

• Neuroendocrinology
• Reproductive Biology
• Molecular Genetics

Background:

• Mammalian reproductive cyclicity depends on gonadotropin-releasing hormone (GnRH) release from the hypothalamus.
• Neuronal and glial inputs regulate GnRH secretion, but transcriptional control remains unclear.
• Enhanced at puberty 1 (EAP1) is a candidate gene regulating neuroendocrine reproductive function.

Purpose of the Study:

• To investigate the role of EAP1 in the neuroendocrine control of reproductive cyclicity in higher primates.
• To determine if EAP1 is essential for maintaining menstrual cyclicity in female rhesus monkeys.

Main Methods:

• Lentiviral-mediated RNA interference (RNAi) was used to knock down EAP1 expression in the medial basal hypothalamus-arcuate nucleus region of female rhesus monkeys.
• Control groups included animals receiving unrelated small interfering RNA (siRNA) or EAP1 siRNA delivered outside the target region.

Main Results:

• Region-specific knockdown of EAP1 in the medial basal hypothalamus-arcuate nucleus resulted in the cessation of menstrual cyclicity.
• Control interventions did not disrupt normal menstrual cycles, confirming the specificity of the EAP1 effect.
• These findings extend previous observations from rodent models to higher primates.

Conclusions:

• Region-specific expression of EAP1 within the hypothalamus is essential for maintaining menstrual cyclicity in female primates.
• EAP1 may regulate reproductive cyclicity by acting as a transcriptional repressor, potentially inhibiting genes involved in neuroendocrine control.
• Further research is needed to elucidate the precise cellular mechanisms by which EAP1 influences reproductive function.