Mechanism of human papillomavirus binding to human spermatozoa and fertilizing ability of infected spermatozoa

Carlo Foresta; Cristina Patassini; Alessandro Bertoldo; Massimo Menegazzo; Felice Francavilla; Luisa Barzon; Alberto Ferlin

doi:10.1371/journal.pone.0015036

Male Fertility Male Factor Causes

Mechanism of human papillomavirus binding to human spermatozoa and fertilizing ability of infected spermatozoa

Foresta C, Patassini C, Bertoldo A, Menegazzo M, Francavilla F, Barzon L, Ferlin A

Published March 7, 2011 PloS one

DOI 10.1371/journal.pone.0015036 PMID 21408100 PMC PMC3051064

RRM Academy Synopsis

HPV protein binds human sperm and reaches hamster eggs in lab tests

HPV capsid protein L1 binds syndecan-1 on the head of human sperm, a 2011 laboratory study of sperm from volunteers reports. Sperm engineered to carry HPV genes delivered them into hamster eggs, which transcribed them. Sperm exposed to L1 also carried that protein into the eggs.

Key Findings

Fluorescence in situ hybridization found an HPV DNA signal in about 25% of sperm from a man whose semen carried HPV16, located in the sperm head.
Immunofluorescence placed the capsid protein L1 in the sperm head, mainly at the equatorial region, and the signal persisted there after the acrosome reaction.
Sperm expressed syndecan-1 mainly at the equatorial region, L1 and syndecan-1 colocalized there, and treatment with heparinase III abolished HPV binding to sperm.
Sperm transfected with HPV E6/E7 genes penetrated hamster eggs, with a lower mean number of sperm per egg than control sperm; eggs then showed viral gene transcription by RT-PCR.
Sperm exposed to HPV16 L1 capsid protein also penetrated hamster eggs and transferred the L1 protein into them.

Interpretation

This laboratory study tested sperm from volunteer donors using the hamster egg-human sperm penetration test, in which human sperm penetrate hamster eggs. The authors note that sperm engineered to carry HPV genes is an artificial model, so they also tested sperm exposed to the L1 protein directly and got the same result. The findings support larger studies of how HPV affects sperm and early embryo development.

RRM Context

Restorative reproductive medicine evaluates both partners, since the cause of a problem may sit with either one. The authors' earlier study found HPV in the semen of asymptomatic young men, and infected sperm had reduced motility. Semen infection is one male-side factor a cause-based evaluation can consider. This paper adds a laboratory mechanism for how the virus attaches to sperm.

Our editorial summary of this paper, not the article's abstract.

Abstract

Human papillomaviruses (HPVs) are agents of the most common sexually transmitted diseases in females and males. Precise data about the presence, mechanism of infection and clinical significance of HPV in the male reproductive tract and especially in sperm are not available. Here we show that HPV can infect human sperm, it localizes at the equatorial region of sperm head through interaction between the HPV capsid protein L1 and syndecan-1. Sperm transfected with HPV E6/E7 genes and sperm exposed to HPV L1 capsid protein are capable to penetrate the oocyte and transfer the virus into oocytes, in which viral genes are then activated and transcribed. These data show that sperm might function as vectors for HPV transfer into the oocytes, and open new perspectives on the role of HPV infection in males and are particularly intriguing in relation to assisted reproduction techniques.

Topics

Male Fertility › Male Factor Causes › Lifestyle and Environment · General Gynecology › Infections › Vaginal and Cervical Infections

Carlo Foresta, Cristina Patassini, Alessandro Bertoldo, Massimo Menegazzo, Felice Francavilla, Luisa Barzon, Alberto Ferlin

C Foresta, C Patassini, A Bertoldo, M Menegazzo, F Francavilla, L Barzon, A Ferlin

PMID 21408100 21408100 DOI 10.1371/journal.pone.0015036 10.1371/journal.pone.0015036 Foresta et al. 2011, Foresta 2011

Mechanism of human papillomavirus binding to human spermatozoa and fertilizing ability of infected spermatozoa

HPV protein binds human sperm and reaches hamster eggs in lab tests

Key Findings

Interpretation

RRM Context

Abstract

Topics

By this author

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