Liquid chromatography-tandem mass spectrometry reveals an active response to DNA damage in human spermatozoa

Abstract

Objective: To investigate how endogenously elevated DNA fragmentation alters the human sperm proteome, and whether this fragmentation contributes to genomic deletions.

Design: Research study.

Setting: Commercial fertility clinic.

Patient(s): Men with low (0%-4%, n = 7) or high (≥16%, n = 6) sperm DNA fragmentation, as assessed by terminal deoxynucleotidyl transferase dUTP nick end labeling assay.

Intervention(s): None.

Main outcome measure(s): Global sperm proteome, single-nucleotide polymorphism genotyping array.

Result(s): A total of 78 significantly differentially abundant proteins (30 decreased, 48 increased) were observed in control vs. high DNA damage samples. DNA damage resulted in robust proteomic responses, including markers of oxidative stress and apoptosis, DNA damage repair proteins, and transcription/translation and protein turnover machinery. Several key sperm functional proteins were significantly decreased in ejaculates with high DNA damage. We were unable to substantiate a link between increased DNA fragmentation and genomic deletions in human spermatozoa.

Conclusion(s): Developing human spermatozoa initiate an active transcriptional response to endogenous DNA damage, which manifests as alterations in the sperm proteome.

Keywords: DNA damage; TUNEL; proteome; sperm.