Mobilisation of Ca2+ stores and flagellar regulation in human sperm by S-nitrosylation: a role for NO synthesised in the female reproductive tract

Gisela Machado-Oliveira, Linda Lefievre, Christopher Ford, M. Belen Herrero, Christopher Barratt, Thomas J. Connolly, Katherine Nash, Aduen Morales-Garcia, Jackson Kirkman-Brown, Steve Publicover

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    Generation of NO by nitric oxide synthase (NOS) is implicated in gamete interaction and fertilisation. Exposure of human spermatozoa to NO donors caused mobilisation of stored Ca2+ by a mechanism that did not require activation of guanylate cyclase but was mimicked by S-nitroso-glutathione (GSNO; an S-nitrosylating agent). Application of dithiothreitol, to reduce protein -SNO groups, rapidly reversed the actions of NO and GSNO on [Ca2+](i). The effects of NO, GSNO and dithiothreitol on sperm protein S-nitrosylation, assessed using the biotin switch method, closely paralleled their actions on [Ca2+](i). Immunofluorescent staining revealed constitutive and inducible NOS in human oviduct and cumulus (the cellular layer investing the oocyte). 4,5-diaminofluorescein (DAF) staining demonstrated production of NO by these tissues. Incubation of human sperm with oviduct explants induced sperm protein S-nitrosylation resembling that induced by NO donors and GSNO. Progesterone (a product of cumulus cells) also mobilises stored Ca2+ in human sperm. Pre-treatment of sperm with NO greatly enhanced the effect of progesterone on [Ca2+](i), resulting in a prolonged increase in flagellar excursion. We conclude that NO regulates mobilisation of stored Ca2+ in human sperm by protein S-nitrosylation, that this action is synergistic with that of progesterone and that this synergism is potentially highly significant in gamete interactions leading to fertilisation.

    Original languageEnglish
    Pages (from-to)3677-3686
    Number of pages10
    Issue number22
    Early online date8 Oct 2008
    Publication statusPublished - 2008


    • Calcium
    • Cumulus
    • Motility
    • Nitric oxide
    • Oviduct
    • Sperm
    • Human
    • Nitric oxide synthase
    • Mitochondrial permeability transition
    • Adenine nucleotide translocase
    • Sensitive guanylyl cyclase
    • Human spermatozoa
    • Acrosome reaction
    • In vitro
    • Cumulus cells
    • L-arginine
    • Embryonic development

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