TY - JOUR
T1 - Antimicrobial peptide LL-37 and its truncated forms, GI-20 and GF-17, exert spermicidal effects and microbicidal activity against Neisseria gonorrhoeae
AU - Kiattiburut, Wongsakorn
AU - Zhi, Ruina
AU - Lee, Seung Gee
AU - Foo, Alexander C.
AU - Hickling, Duane R.
AU - Keillor, Jeffrey W.
AU - Goto, Natalie K.
AU - Li, Weihua
AU - Conlan, Wayne
AU - Angel, Jonathan B.
AU - Wang, Guangshun
AU - Tanphaichitr, Nongnuj
PY - 2018
Y1 - 2018
N2 - STUDY QUESTION: Do the truncated LL-37 peptides, GI-20 and GF-17, have spermicidal activity and microbicidal effects on the sexually transmitted infection (STI) pathogen Neisseria gonorrhoeae with equivalent potency to LL-37? SUMMARY ANSWER: GI-20 and GF-17 exhibited spermicidal effects on both mouse and human sperm as well as microbicidal action on N. gonorrhoeae with the same efficacy as LL-37. WHAT IS KNOWN ALREADY: The antimicrobial peptide LL-37 exerts microbicidal activity against various STI pathogens as well as spermicidal effects on both mouse and human sperm. STUDY DESIGN, SIZE, DURATION: Spermicidal activities of GI-20 and GF-17 were evaluated in vitro in mouse and human sperm and in vivo in mice. Finally, in vitro antimicrobial effects of LL-37, GI-20 and GF-17 on an STI pathogen, N. gonorrhoeae were determined. All experiments were repeated three times or more. In particular, sperm samples from different males were used on each experimental day. PARTICIPANTS/MATERIALS, SETTING, METHODS: The plasma membrane integrity of peptide-treated sperm was assessed by cellular exclusion of Sytox Green, a membrane impermeable fluorescent DNA dye. Successful mouse in vitro fertilization was revealed by the presence of two pronuclei in oocytes following co-incubation with capacitated untreated/peptide-pretreated sperm. Sperm plus each peptide were transcervically injected into female mice and the success of in vivo fertilization was scored by the formation of 2-4 cell embryos 42 h afterward. Reproductive tract tissues of peptide pre-exposed females were then assessed histologically for any damage. Minimal inhibitory/ bactericidal concentrations of LL-37, GI-20 and GF-17 on N. gonorrhoeae were determined by a standard method. MAIN RESULTS AND THE ROLE OF CHANCE: Like LL-37, treatment of sperm with GI-20 and GF-17 resulted in dose-dependent increases in sperm plasma membrane permeabilization, reaching the maximum at 18 and 3.6 μM for human and mouse sperm, respectively (P < 0.0001, as compared with untreated sperm). Mouse sperm treated with 3.6 μM GI-20 or GF-17 did not fertilize oocytes either in vitro or in vivo. Moreover, reproductive tract tissues of female mice pre-exposed to 3.6 μM GI-20 or GF-17 remained intact with no lesions, erosions or ulcerations. At 1.8-7.2 μM, LL-37, GI-20 and GF-17 exerted bactericidal effects on N. gonorrhoeae. LARGE SCALE DATA: N/A LIMITATIONS, REASONS FOR CAUTION: Direct demonstration of the inhibitory effects of GI-20 and GF-17 on human in vitro and in vivo fertilization cannot be performed due to ethical issues. WIDER IMPLICATIONS OF THE FINDINGS: Like LL-37, GI-20 and GF-17 acted as spermicides and microbicides against N. gonorrhoeae, without adverse effects on female reproductive tissues. With lower synthesis costs, GI-20 and GF-17 are attractive peptides for further development into vaginal spermicides/microbicides. STUDY FUNDING/COMPETING INTEREST(S): This work was supported by Canadian Institutes of Health Research (MOP119438 and CCI82413 to N.T.) and NIH (R01 AI105147 to G.W.). There are no competing interests to declare.
AB - STUDY QUESTION: Do the truncated LL-37 peptides, GI-20 and GF-17, have spermicidal activity and microbicidal effects on the sexually transmitted infection (STI) pathogen Neisseria gonorrhoeae with equivalent potency to LL-37? SUMMARY ANSWER: GI-20 and GF-17 exhibited spermicidal effects on both mouse and human sperm as well as microbicidal action on N. gonorrhoeae with the same efficacy as LL-37. WHAT IS KNOWN ALREADY: The antimicrobial peptide LL-37 exerts microbicidal activity against various STI pathogens as well as spermicidal effects on both mouse and human sperm. STUDY DESIGN, SIZE, DURATION: Spermicidal activities of GI-20 and GF-17 were evaluated in vitro in mouse and human sperm and in vivo in mice. Finally, in vitro antimicrobial effects of LL-37, GI-20 and GF-17 on an STI pathogen, N. gonorrhoeae were determined. All experiments were repeated three times or more. In particular, sperm samples from different males were used on each experimental day. PARTICIPANTS/MATERIALS, SETTING, METHODS: The plasma membrane integrity of peptide-treated sperm was assessed by cellular exclusion of Sytox Green, a membrane impermeable fluorescent DNA dye. Successful mouse in vitro fertilization was revealed by the presence of two pronuclei in oocytes following co-incubation with capacitated untreated/peptide-pretreated sperm. Sperm plus each peptide were transcervically injected into female mice and the success of in vivo fertilization was scored by the formation of 2-4 cell embryos 42 h afterward. Reproductive tract tissues of peptide pre-exposed females were then assessed histologically for any damage. Minimal inhibitory/ bactericidal concentrations of LL-37, GI-20 and GF-17 on N. gonorrhoeae were determined by a standard method. MAIN RESULTS AND THE ROLE OF CHANCE: Like LL-37, treatment of sperm with GI-20 and GF-17 resulted in dose-dependent increases in sperm plasma membrane permeabilization, reaching the maximum at 18 and 3.6 μM for human and mouse sperm, respectively (P < 0.0001, as compared with untreated sperm). Mouse sperm treated with 3.6 μM GI-20 or GF-17 did not fertilize oocytes either in vitro or in vivo. Moreover, reproductive tract tissues of female mice pre-exposed to 3.6 μM GI-20 or GF-17 remained intact with no lesions, erosions or ulcerations. At 1.8-7.2 μM, LL-37, GI-20 and GF-17 exerted bactericidal effects on N. gonorrhoeae. LARGE SCALE DATA: N/A LIMITATIONS, REASONS FOR CAUTION: Direct demonstration of the inhibitory effects of GI-20 and GF-17 on human in vitro and in vivo fertilization cannot be performed due to ethical issues. WIDER IMPLICATIONS OF THE FINDINGS: Like LL-37, GI-20 and GF-17 acted as spermicides and microbicides against N. gonorrhoeae, without adverse effects on female reproductive tissues. With lower synthesis costs, GI-20 and GF-17 are attractive peptides for further development into vaginal spermicides/microbicides. STUDY FUNDING/COMPETING INTEREST(S): This work was supported by Canadian Institutes of Health Research (MOP119438 and CCI82413 to N.T.) and NIH (R01 AI105147 to G.W.). There are no competing interests to declare.
KW - Antimicrobial peptide
KW - GF-17
KW - GI-20
KW - LL-37
KW - Lactobacillus crispatus
KW - Microbicide
KW - Neisseria gonorrhoeae
KW - Sperm-fertilizing ability
KW - Spermicide
KW - Vaginal contraceptive
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U2 - 10.1093/humrep/dey315
DO - 10.1093/humrep/dey315
M3 - Article
C2 - 30357408
AN - SCOPUS:85056576964
VL - 33
SP - 2175
EP - 2183
JO - Human Reproduction
JF - Human Reproduction
SN - 0268-1161
IS - 12
ER -