Andrology. 2022 Sep 4. doi: 10.1111/andr.13289. Online ahead of print.
ABSTRACT
BACKGROUND: The cellular and molecular mechanisms of the events that help spermatozoa acquire their fertilizing capability during capacitation and acrosome reaction are not completely understood.
OBJECTIVE: This study was performed with a postulation that identification of sperm proteins and their changes during in vitro capacitation and acrosome reaction will unravel unknown molecular aspects of fertilization that impact male fertility.
MATERIALS AND METHODS: Spermatozoa collected from sequential conditions, i.e. separation of ejaculated spermatozoa by Percoll gradient centrifugation, in vitro capacitation, and acrosome reaction were processed for tandem mass spectrometric analysis, followed by protein identification, label-free quantitation, and statistical analysis.
RESULTS AND DISCUSSION: Collectively, a total of 1088 sperm proteins were identified. In comparison to ejaculated spermatozoa, 44 and 141 proteins were differentially expressed in capacitated and acrosome reacted spermatozoa, respectively. A large number of proteins were found downregulated, including clusterin, pyruvate dehydrogenase E1 component, semenogelin-1 and 2, heat shock protein 90, beta-microseminoprotein and keratin. It was expected as sperm-membrane-associated proteins are removed during capacitation. There were significant proteomic alterations in asthenozoospermia (AZS) compared to normozoospermia (NZS); however, variation was more noticeable among proteins of acrosome reacted spermatozoa and those released during the acrosome reaction. The processes enriched among downregulated proteins in AZS included acrosome assembly, binding of sperm to zona pellucida, nucleosome assembly, flagellated sperm motility, protein folding, oxidative phosphorylation, TCA cycle, chromatin silencing, gluconeogenesis, glycolytic process, and glycolysis.
CONCLUSION: The dynamic information generated about proteomic alterations in spermatozoa during capacitation and acrosome reaction and their variability in AZS will contribute not only towards enhancing our understanding of processes that prepare spermatozoa to acquire fertilization capability but also help in deciphering novel factors of male infertility. This article is protected by copyright. All rights reserved.
PMID:36057948 | DOI:10.1111/andr.13289
