Investigation of male infertility using quantitative comparative proteomics

Area of Science:

• Proteomics
• Male Reproductive Biology
• Biomarker Discovery

Background:

• Male factors contribute significantly to infertility, necessitating molecular insights.
• Understanding sperm protein expression differences is crucial for diagnosing male infertility.

Purpose of the Study:

• To compare sperm proteomes of fertile men, infertile men, and those with in vitro fertilization (IVF) failure.
• To identify differentially expressed proteins as potential biomarkers for male infertility.

Main Methods:

• Differential proteomics using isobaric tags for relative and absolute quantitation (iTRAQ) labeling.
• Liquid chromatography-mass spectrometry (LC-MS) analysis for protein identification and quantification.
• Validation of candidate biomarkers via multiple reactions monitoring mass spectrometry (MRM-MS) and Western blot.

Main Results:

• A total of 348 unique proteins were identified and quantified.
• 33 proteins were differentially expressed in the IVF-failure group compared to the fertile group.
• Four proteins—semenogelin 1 (SEMG1), prolactin-induced protein (PIP), glyceraldehyde-3-phosphate dehydrogenase (GAPDHS), and phosphoglycerate kinase 2 (PGK2)—were consistently altered in infertile and IVF-failure groups.

Conclusions:

• The study identified specific protein alterations associated with male infertility.
• A panel of proteins, including SEMG1, PIP, GAPDHS, and PGK2, shows promise as potential diagnostic biomarkers for male infertility.
• Further research is warranted to validate these protein markers for clinical application.