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ORIGINAL RESEARCH article

Front. Cell Dev. Biol.
Sec. Molecular and Cellular Reproduction
Volume 12 - 2024 | doi: 10.3389/fcell.2024.1275116

The sperm-specific K + channel Slo3 is inhibited by albumin and steroids contained in reproductive fluids

Provisionally accepted
Christoph Brenker Christoph Brenker 1*Johannes Lorenz Johannes Lorenz 1Clara Eisenhardt Clara Eisenhardt 1Alexandra Kulle Alexandra Kulle 2Paul-Martin Holterhus Paul-Martin Holterhus 2Manfred Fobker Manfred Fobker 3Wolfgang Boenigk Wolfgang Boenigk 4Verena Nordhoff Verena Nordhoff 1Hermann M. Behre Hermann M. Behre 5Timo Strünker Timo Strünker 1
  • 1 Centre of Reproductive Medicine and Andrology, University Hospital Münster, University of Münster, Münster, North Rhine-Westphalia, Germany
  • 2 Division of Pediatric Endocrinology and Diabetes, Department of Pediatrics, Christian-Albrechts-University, Kiel, Schleswig-Holstein, Germany
  • 3 Center for Laboratory Medicine, University Hospital Münster, Münster, North Rhine-Westphalia, Germany
  • 4 Max Planck Institute for Neurobiology of Behaviour – caesar, Bonn, Germany
  • 5 Fertility Centre, University Hospital Münster, Münster, North Rhine-Westphalia, Germany

The final, formatted version of the article will be published soon.

    To locate and fertilize the egg, sperm probe the varying microenvironment prevailing at different stages during their journey across the female genital tract. To this end, they are equipped with a unique repertoire of mostly sperm-specific proteins. In particular, the flagellar Ca 2+ channel CatSper has come into focus as a polymodal sensor used by human sperm to register ligands released into the female genital tract. Here, we provide the first comprehensive study on the pharmacology of the sperm-specific human Slo3 channel, shedding light on its modulation by reproductive fluids and their constituents. We show that seminal fluid and contained prostaglandins and Zn 2+ do not affect the channel, whereas human Slo3 is inhibited in a nongenomic fashion by diverse steroids as well as by albumin, which are both released into the oviduct along with the egg. This indicates that not only CatSper but also Slo3 harbours promiscuous ligand-binding sites that can accommodate structurally diverse molecules, suggesting that Slo3 is involved in chemosensory signalling in human sperm.

    Keywords: Human sperm, ion channel, sperm signaling, reproductive tract, Follicular Fluid

    Received: 09 Aug 2023; Accepted: 19 Jul 2024.

    Copyright: © 2024 Brenker, Lorenz, Eisenhardt, Kulle, Holterhus, Fobker, Boenigk, Nordhoff, Behre and Strünker. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

    * Correspondence: Christoph Brenker, Centre of Reproductive Medicine and Andrology, University Hospital Münster, University of Münster, Münster, North Rhine-Westphalia, Germany

    Disclaimer: All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article or claim that may be made by its manufacturer is not guaranteed or endorsed by the publisher.