Elevated aminopeptidase N affects sperm motility and early embryo development.

Area of Science:

• Reproductive Biology
• Enzymology
• Sperm Physiology

Background:

• Aminopeptidase N (APN) is an ectopeptidase found in mammalian semen.
• APN is known to negatively affect male fertility by altering sperm motility.
• This enzyme constitutes a significant portion of seminal plasma proteins and is transferred to sperm.

Purpose of the Study:

• To investigate the molecular mechanism of Aminopeptidase N (APN).
• To elucidate the role of APN in regulating sperm functions and male fertility.
• To understand the impact of APN on early embryonic development.

Main Methods:

• In vitro incubation of epididymal mouse spermatozoa with recombinant mouse APN.
• Measurement of APN activity, sperm motility parameters (motility, hyperactivated motility, speed), viability, and acrosome reaction.
• Assessment of early embryonic development following exposure to altered APN activity.

Main Results:

• Supplementation with recombinant APN significantly increased APN activity in sperm culture medium.
• Increased APN activity altered sperm motility, hyperactivated motility, swimming speeds, viability, and acrosome reaction.
• Elevated APN activity negatively impacted early embryonic development, potentially due to increased sperm toxicity, independent of protein tyrosine phosphorylation and PKA activity.

Conclusions:

• Aminopeptidase N (APN) plays a crucial role in regulating sperm functions and early embryonic development.
• Increased APN activity in semen can lead to adverse effects on male fertility.
• Understanding APN's role is vital for addressing male infertility causes.