Publication:
Antimicrobial host defence peptide, LL-37, as a potential vaginal contraceptive

Issued Date

2014-01-01

Resource Type

Article

ISSN

14602350
02681161

DOI

10.1093/humrep/deu018

Other identifier(s)

2-s2.0-84898944079

Rights

Mahidol University

Rights Holder(s)

SCOPUS

Bibliographic Citation

Human Reproduction. Vol.29, No.4 (2014), 683-696

Suggested Citation

Nopparat Srakaew, Charlene D. Young, Arpornrad Sae-Wu, Hongbin Xu, Krista L. Quesnel, Riccardo Di Brisco, Kessiri Kongmanas, Duriya Fongmoon, Greanggrai Hommalai, Wattana Weerachatyanukul, Susan H. Hall, Yong Lian Zhang, Luigi Panza, Laura Franchini, Federica Compostella, Terry W. Pearson, Robert E. Hancock, Richard J. Oko, Louis S. Hermo, Nongnuj Tanphaichitr Antimicrobial host defence peptide, LL-37, as a potential vaginal contraceptive. Human Reproduction. Vol.29, No.4 (2014), 683-696. doi:10.1093/humrep/deu018 Retrieved from: https://repository.li.mahidol.ac.th/handle/20.500.14594/34853

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Title

Antimicrobial host defence peptide, LL-37, as a potential vaginal contraceptive

Author(s)

Nopparat Srakaew
 Charlene D. Young
 Arpornrad Sae-Wu
 Hongbin Xu
 Krista L. Quesnel
 Riccardo Di Brisco
 Kessiri Kongmanas
 Duriya Fongmoon
 Greanggrai Hommalai
 Wattana Weerachatyanukul
 Susan H. Hall
 Yong Lian Zhang
 Luigi Panza
 Laura Franchini
 Federica Compostella
 Terry W. Pearson
 Robert E. Hancock
 Richard J. Oko
 Louis S. Hermo
 Nongnuj Tanphaichitr

Other Contributor(s)

Ottawa Hospital Research Institute
 University of Ottawa, Canada
 Mahidol University
 The University of North Carolina at Chapel Hill
 Chinese Academy of Sciences
 Universita degli Studi del Piemonte Orientale Amedeo Avogadro, Novara
 Universita degli Studi di Milano
 University of Victoria
 The University of British Columbia
 Queen's University, Kingston
 McGill University

Abstract

STUDY QUESTIONDoes antimicrobial peptide, LL-37, inhibit sperm fertilizing ability?SUMMARY ANSWEROur results indicate that LL-37 inhibits mouse and human sperm fertilizing ability.WHAT IS KNOWN ALREADYLL-37, a cationic antimicrobial peptide, exerts its microbicidal effects through the disruption of microbial cytoplasmic membranes following its interaction with microbial surface anionic phospholipids. ALL-38 (an LL-37 close analogue: LL-37 + Ala at the N-terminus) is produced in the vagina 2-6 h post-intercourse from its precursor hCAP-18, a seminal plasma component. At this time, motile sperm have already swum into the uterine cavity, thus unexposed to ALL-38. Since sperm contain a substantial amount of acidic sulfogalactosylglycerolipid (SGG) on their surface, treatment of sperm with LL-37 may cause their membrane disruption in an analogous manner to that occurring on microbial membranes.STUDY DESIGN, SIZE AND DURATIONMouse/human sperm treated (2-30 min) with LL-37 in a physiological concentration range (up to 10.8 μM) were assessed for SGG-dependent LL-37 binding, and parameters relevant to fertilizing ability, namely motility and intactness of the sperm acrosome and plasma membrane. Ability of mouse sperm to fertilize eggs in vitro was also evaluated. Each study was performed with greater than or equal to three different sperm samples. The efficacy of LL-37 to inhibit sperm fertilizing ability in vivo was determined in female mice (n = 26 each for LL-37 treatment and no treatment), using sperm retrieved from 26 males.PARTICIPANTS/MATERIALS, SETTING, METHODSHuman sperm samples were donated by fertile men. LL-37 was chemically synthesized and was biotinylated for sperm binding studies. Sperm motility was assessed by videomicroscopy and the acrosomal status by Coomassie blue staining of acrosome-intact mouse sperm or the exposure of CD46, an inner acrosomal membrane protein, of acrosome reacted human sperm. Sperm membrane permeabilization/disruption was assessed by the loss of hypo-osmotic swelling response, an incorporation of Sytox Green (a membrane impermeable fluorescent DNA dye), and electron microscopy. Mouse IVF was scored by the presence of two pronuclei in eggs 6 h post-insemination. Ability of mouse sperm to fertilize eggs in vivo was determined by the pregnancy outcome of female mice injected transcervically with sperm with or without LL-37.MAIN RESULTS AND THE ROLE OF CHANCEBiotinylated LL-37 bound to both mouse and human sperm and the binding was partially dependent on sperm surface SGG. Mouse and human sperm became immotile and underwent a premature acrosome reaction upon treatment with LL-37 at 3.6 and 10.8 μM, respectively. The initial action of LL-37 on both mouse and human sperm appeared to be through permeabilization/ disruption of sperm surface membranes evidenced by the loss of hypo-osmotic swelling response, Sytox Green staining and electron microscopy revealing ultrastructural damage. Mouse sperm treated with 3.6 μM LL-37 lost the ability to fertilize eggs both in vitro and in vivo. All 26 female mice inseminated with sperm and LL-37 did not become pregnant. No apparent damage to the reproductive tract was observed as revealed by histological characterization in LL-37-inseminated mice and these females resumed fecundity following mating with fertile males.LIMITATIONS, REASONS FOR CAUTIONDirect demonstration that LL-37 treated human sperm fail to fertilize eggs was limited by legal restrictions on obtaining human eggs for such use.WIDER IMPLICATIONS OF THE FINDINGSOur results reveal selective inhibitory effects of LL-37 on sperm fertilizing ability in mice without apparent impairment to the female reproductive tract. LL-37 is therefore a promising candidate to be developed into a vaginal contraceptive with microbicidal activity.STUDY FUNDING/COMPETING INTEREST(S)This work was supported by Grand Challenges Explorations grant from the Bill & Melinda Gates Foundation (OPP1024509), Canadian Institutes of Health Research (MOP119438 & CCI82413) and International Collaboration and Exchanges NSFC of China (No.30611120525). There are no competing interests to declare. © The Author 2014.

Keyword(s)

Medicine

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https://repository.li.mahidol.ac.th/handle/20.500.14594/34853

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