Update on the proteomics of male infertility: A systematic review

Peer review under responsibility of Arab Association of Urology.

Abstract

Objective: To assess the role of differentially expressed proteins as a resource for potential biomarker identification of infertility, as male infertility is of rising concern in reproductive medicine and evidence pertaining to its aetiology at a molecular level particularly proteomic as spermatozoa lack transcription and translation. Proteomics is considered as a major field in molecular biology to validate the target proteins in a pathophysiological state. Differential expression analysis of sperm proteins in infertile men and bioinformatics analysis offer information about their involvement in biological pathways.

Materials and methods: Literature search was performed on PubMed, Medline, and Science Direct databases using the keywords ‘sperm proteomics’ and ‘male infertility’. We also reviewed the relevant cross references of retrieved articles and included them in the review process. Articles written in any language other than English were excluded.

Results: Of 575 articles identified, preliminary screening for relevant studies eliminated 293 articles. At the next level of selection, from 282 studies only 80 articles related to male infertility condition met the selection criteria and were included in this review.

Conclusion: In this molecular era, sperm proteomics has created a platform for enhanced understanding of male reproductive physiology as a potential tool for identification of novel protein biomarkers related to sperm function in infertile men. Therefore, it is believed that proteomic biomarkers can overcome the gaps in information from conventional semen analysis that are of limited clinical utility.

Keywords:

• Sperm proteomics
• Male infertility
• Spermatozoa
• Varicocele
• Biomarkers

Notes

Peer review under responsibility of Arab Association of Urology.

1 Abbreviations: ACPP, prostatic acid phosphatase/prostatic-specific acid phosphatase; ANXA7, annexin A7; AZGP1, zinc α2-glycoprotein 1; CLU, clusterin; CRISP(1)(3),cysteine-rich secretory protein (1) (3); CRISPLD(1)(2), CRISP LCCL domain-containing (1) (2); CST3, cystatin 3; 2D, two dimensional; DEP, differentially expressed protein; FN1, fibronectin 1; GO, gene ontology; HIST1H2BA, histone cluster 1 H2B family member A; HSP, heat shock protein; HSPA(2)(5), HSP family A (HSP70) member (2) (5); KLK3, kallikrein 3; LC–(MS), liquid chromatography–(mass spectrometry); LGALS3BP, galectin-3 binding protein; MALDI-TOF, matrix-assisted laser desorption ionisation time-of-flight; MIF, macrophage migration inhibitory factor; NSAF, normalised spectral abundance factor; (N)OA, (non-) obstructive azoospermia; OAT, oligoasthenozoospermia; ODF(1), outer dense fibre of sperm tails (1) (2); OS, oxidative stress; PAEP, progestogen-associated endometrial protein/glycodelin S; PGK2, phosphoglycerate kinase 2; PIP, prolactin induced protein; ROS, reactive oxygen species; SDS, sodium dodecyl sulphate; SEMG(1)(2), semenogelin (1) (2); SOD1, superoxide dismutase 1; SpC, spectral count; TEX101, testis-expressed protein 101; TUNEL, terminal deoxynucleotidyl transferase-mediated dUTP nick-end labelling; VDAC(2)(3), voltage-dependent anion channel (2) (3); ZPBP2, zona pellucida binding protein 2.