Molecular interplay between sperm and oocyte: a narrative review

Area of Science:

• Reproductive Biology
• Molecular Genetics
• Developmental Biology

Background:

• Fertilization involves complex sperm-oocyte interactions, including penetration of the cumulus oocyte complex and zona pellucida (ZP), and fusion with the oolemma.
• Oocyte activation triggers blocks to polyspermy at the ZP and oolemma, ensuring monospermy.
• Studying human fertilization is challenging due to ethical constraints and limited patient data.

Purpose of the Study:

• To review molecular mechanisms of mammalian sperm-oocyte interactions.
• To summarize genetic causes of infertility related to fertilization defects.
• To explore novel experimental approaches for human fertilization research and potential applications in diagnostics and contraception.

Main Methods:

• Comprehensive literature search of PubMed, Google Scholar, and Scopus.
• Inclusion of studies on mammalian fertilization, sperm-oocyte interactions, ZP, cumulus cells, polyspermy, and human infertility.
• Exclusion of non-mammalian species and non-peer-reviewed preprints.

Main Results:

• Mammalian fertilization knowledge largely comes from animal models, detailing cumulus dispersal, acrosomal protein translocation, and ZP cleavage for polyspermy block.
• Translating animal findings to human biology requires careful validation.
• Interdisciplinary approaches like humanized mouse models and artificial oocytes offer insights into human gamete interactions.

Conclusions:

• Advances in understanding sperm-oocyte interactions will aid in developing diagnostics and therapeutics for fertilization defects.
• These insights can guide the development of targeted, reversible contraceptives.