Seminal vesicle secretion 2 acts as a protectant of sperm sterols and prevents ectopic sperm capacitation in mice.
Seminal vesicle secretion 2 (SVS2) is a protein secreted by the mouse seminal vesicle. We previously demonstrated that SVS2 regulates fertilization in mice; SVS2 is attached to a ganglioside GM1 on the plasma membrane of the sperm head and inhibits sperm capacitation in in vitro fertilization as a decapacitation factor. Furthermore, male mice lacking SVS2 display prominently reduced fertility in vivo, which indicates that SVS2 protects spermatozoa from some spermicidal attack in the uterus. In this study, we tried to investigate the mechanisms by which SVS2 controls in vivo sperm capacitation. SVS2-deficient males that mated with wild-type partners resulted in decreased cholesterol levels on ejaculated sperm in the uterine cavity. SVS2 prevented cholesterol efflux from the sperm plasma membrane and incorporated liberated cholesterol in the sperm plasma membrane, thereby reversibly preventing the induction of sperm capacitation by bovine serum albumin and methyl-beta-cyclodextrin in vitro. SVS2 enters the uterus and the uterotubal junction, arresting sperm capacitation in this area. Therefore, our results show that SVS2 keeps sterols on the sperm plasma membrane and plays a key role in unlocking sperm capacitation in vivo.
Misaki Marine Biological Station, School of Science, University of Tokyo, Miura, Japan.
Naoya
N
Araki
Department of Nuclear Medicine, University of Debrecen, Debrecen, Hungary.
György
G
Trencsényi
Department of Obstetrics and Gynecology, University of Debrecen, Debrecen, Hungary.
Zoárd T
ZT
Krasznai
Department of Biophysics and Cell Biology, University of Debrecen, Debrecen, Hungary.
Enikő
E
Nizsalóczki
Misaki Marine Biological Station, School of Science, University of Tokyo, Miura, Japan.
Ayako
A
Sakamoto
Department of Reproductive Biology, National Center for Child Health and Development, Tokyo, Japan.
Natsuko
N
Kawano
Department of Reproductive Biology, National Center for Child Health and Development, Tokyo, Japan.
Kenji
K
Miyado
Biomedical Engineering Center, Toin University of Yokohama, Yokohama, Japan.
Kaoru
K
Yoshida
Misaki Marine Biological Station, School of Science, University of Tokyo, Miura, Japan Center for Marine Biology, University of Tokyo, Miura, Japan yoshida@mmbs.s.u-tokyo.ac.jp.
Manabu
M
Yoshida
D000818:Animals; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism; D019610:Cytoprotection / Q000187:drug effects; D005187:Fallopian Tubes / Q000187:drug effects / Q000502:physiology; D005260:Female; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D011994:Recombinant Proteins / Q000494:pharmacology; D029607:Seminal Vesicle Secretory Proteins / Q000494:pharmacology* / Q000502:physiology; D013075:Sperm Capacitation / Q000187:drug effects*; D013094:Spermatozoa / Q000187:drug effects* / Q000378:metabolism; D013261:Sterols / Q000378:metabolism*
D011994:Recombinant Proteins; C520624:SVS2 protein, mouse; D029607:Seminal Vesicle Secretory Proteins; D013261:Sterols
SVS2; cholesterol efflux; seminal plasma; sperm capacitation