Quantitative Glycopeptide Changes in Rat Sperm During Epididymal Transit

Area of Science:

• Reproductive Biology
• Glycomics
• Proteomics

Background:

• Mammalian sperm undergo significant changes during epididymal transit to gain fertilizing potential.
• Alterations in the sperm glycome, particularly sialic acid content, influence cell adhesion and signaling, vital for successful fertilization.
• Limited information exists on sialic acid changes on sperm during epididymal transit.

Purpose of the Study:

• To identify N-linked sialylated glycoproteins on rat epididymal sperm.
• To investigate the regulation of these glycoproteins during epididymal transit.
• To understand the role of sialylated glycoproteins in sperm maturation.

Main Methods:

• Enrichment of sialylated glycopeptides from caput, corpus, and cauda sperm using titanium dioxide beads.
• Enzymatic deglycosylation with PNGase F to release N-linked glycopeptides.
• Analysis of glycopeptides using liquid chromatography tandem-mass spectrometry (LC-MS/MS).

Main Results:

• Identification of 92 unique N-linked sialylated glycopeptides from 65 proteins, including ADAM, Basigin, and TEX101.
• Label-free quantification revealed that 48 out of 92 identified glycopeptides were regulated during epididymal transit.
• The protein TEX101 showed PNGase F-resistant deglycosylation, indicating unique characteristics.

Conclusions:

• Changes in the N-linked sialoglycoprotein profile are a significant aspect of sperm maturation in rats.
• These glycomic alterations are dynamically regulated during epididymal transit.
• The findings provide insights into the molecular mechanisms of sperm maturation and fertilizing capacity.