Isolation, characterization, and function of EBAF/LEFTY B: role in infertility

Area of Science:

• Reproductive biology
• Molecular endocrinology
• Cytokine signaling

Background:

• The human endometrium undergoes cyclic remodeling for embryo implantation.
• Embryonic bleeding-associated factor (EBAF)/LEFTY B is a TGF-β superfamily cytokine involved in tissue remodeling.

Purpose of the Study:

• To investigate the role of EBAF/LEFTY B in human endometrial remodeling, decidualization, and embryo implantation.
• To explore the clinical relevance of EBAF/LEFTY B expression in infertile patients.

Main Methods:

• Cell transfection to study EBAF/LEFTY B protein processing and function.
• Analysis of EBAF/LEFTY B expression in human endometrium across the menstrual cycle.
• Generation of transgenic mice to assess the impact of EBAF/LEFTY B overexpression on implantation.
• Investigation of EBAF/LEFTY B's effect on decidual protein expression and transcription factors (FOXO1, ETS1).

Main Results:

• EBAF/LEFTY B is expressed at low levels during endometrial receptivity and maximally during menstruation.
• EBAF/LEFTY B induces tissue remodeling via matrix metalloproteinase-mediated collagenolysis.
• Premature EBAF/LEFTY B increase during the implantation window was observed in some infertile patients.
• EBAF/LEFTY B overexpression in mice impaired embryo implantation.
• EBAF/LEFTY B inhibits key decidual proteins (IGFBP-1, PRL) by regulating FOXO1 and ETS1 transcription factors.

Conclusions:

• EBAF/LEFTY B plays a critical role in regulating endometrial receptivity, decidualization, and successful embryo implantation.
• Aberrant EBAF/LEFTY B expression may contribute to implantation failure in infertile women.
• EBAF/LEFTY B represents a potential therapeutic target for improving fertility outcomes.