Synergistic activation of CatSper Ca2+ channels in human sperm by oviductal ligands and endocrine disrupting chemicals
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Synergistic activation of CatSper Ca2+ channels in human sperm by oviductal ligands and endocrine disrupting chemicals. / Brenker, C.; Rehfeld, A.; Schiffer, C.; Kierzek, M.; Kaupp, U. B.; Skakkebæk, N. E.; Strünker, T.
In: Human Reproduction, Vol. 33, No. 10, 2018, p. 1915-1923.Research output: Contribution to journal › Journal article › Research › peer-review
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TY - JOUR
T1 - Synergistic activation of CatSper Ca2+ channels in human sperm by oviductal ligands and endocrine disrupting chemicals
AU - Brenker, C.
AU - Rehfeld, A.
AU - Schiffer, C.
AU - Kierzek, M.
AU - Kaupp, U. B.
AU - Skakkebæk, N. E.
AU - Strünker, T.
PY - 2018
Y1 - 2018
N2 - STUDY QUESTION: Does the chemosensory activation of CatSper Ca2+ channels in human sperm give rise to additive, sub-additive or even synergistic actions among agonists? SUMMARY ANSWER: We show that oviductal ligands and endocrine disrupting chemicals (EDCs) activate human CatSper highly synergistically. WHAT IS KNOWN ALREADY: In human sperm, the sperm-specific CatSper channel controls the intracellular Ca2+ concentration and, thereby, several crucial stages toward fertilization. CatSper is activated by oviductal ligands and structurally diverse EDCs. The chemicals mimic the action of the physiological ligands, which might interfere with the precisely coordinated sequence of events underlying fertilization. STUDY DESIGN, SIZE, DURATION: For both oviductal ligands and EDCs, we examined in quantitative terms whether stimulation of human sperm in vitro with mixtures results in additive, sub-additive or synergistic actions. PARTICIPANTS/MATERIALS, SETTING, METHODS: We studied activation of CatSper in sperm of healthy volunteers, using kinetic Ca2+ fluorimetry and patch-clamp recordings. The combined action of progesterone and prostaglandins and of the EDCs benzylidene camphor sulfonic acid (BCSA) and α-Zearalenol was evaluated by curve-shift analysis, curvilinear isobolographic analysis and the combinationindex method. MAIN RESULTS AND THE ROLE OF CHANCE: Analysis of the action of progesterone/prostaglandin and BCSA/α-Zearalenol mixtures in human sperm by fluorimetry revealed that the oviductal ligands and EDCs both evoke Ca2+ influx via CatSper in a highly synergistic fashion. Patch-clamp recordings of CatSper currents in human sperm corroborated the synergistic ligand-activation of the channel. LIMITATIONS, REASONS FOR CAUTION: This is an in vitro study. Future studies have to assess the physiological relevance in vivo. WIDER IMPLICATIONS OF THE FINDINGS: These findings indicate that the fertilization process is orchestrated by multiple oviductal CatSper agonists that act in concert to control the behavior of sperm. Moreover, our results substantiate the concerns regarding the negative impact of EDCs on male reproductive health. So far, safety thresholds like the "No Observed Adverse Effect Level (NOAEL)" or "No Observed Effect Concentration (NOEC)" are set for individual EDCs. Our finding that EDCs act synergistically in human sperm challenges the validity of this procedure. STUDY FUNDING/COMPETING INTEREST(S): This work was supported by the German Research Foundation (SFB 645; CRU326), the Cells-in-Motion (CiM) Cluster of Excellence, Münster, (FF-2016-17), the 'Innovative Medical Research' of the University of Münster Medical School (BR121507), an EDMaRC research grant from the Kirsten and Freddy Johansen's Foundation, and the Innovation Fund Denmark (InnovationsFonden; 14-2013-4). The authors have no competing financial interests.
AB - STUDY QUESTION: Does the chemosensory activation of CatSper Ca2+ channels in human sperm give rise to additive, sub-additive or even synergistic actions among agonists? SUMMARY ANSWER: We show that oviductal ligands and endocrine disrupting chemicals (EDCs) activate human CatSper highly synergistically. WHAT IS KNOWN ALREADY: In human sperm, the sperm-specific CatSper channel controls the intracellular Ca2+ concentration and, thereby, several crucial stages toward fertilization. CatSper is activated by oviductal ligands and structurally diverse EDCs. The chemicals mimic the action of the physiological ligands, which might interfere with the precisely coordinated sequence of events underlying fertilization. STUDY DESIGN, SIZE, DURATION: For both oviductal ligands and EDCs, we examined in quantitative terms whether stimulation of human sperm in vitro with mixtures results in additive, sub-additive or synergistic actions. PARTICIPANTS/MATERIALS, SETTING, METHODS: We studied activation of CatSper in sperm of healthy volunteers, using kinetic Ca2+ fluorimetry and patch-clamp recordings. The combined action of progesterone and prostaglandins and of the EDCs benzylidene camphor sulfonic acid (BCSA) and α-Zearalenol was evaluated by curve-shift analysis, curvilinear isobolographic analysis and the combinationindex method. MAIN RESULTS AND THE ROLE OF CHANCE: Analysis of the action of progesterone/prostaglandin and BCSA/α-Zearalenol mixtures in human sperm by fluorimetry revealed that the oviductal ligands and EDCs both evoke Ca2+ influx via CatSper in a highly synergistic fashion. Patch-clamp recordings of CatSper currents in human sperm corroborated the synergistic ligand-activation of the channel. LIMITATIONS, REASONS FOR CAUTION: This is an in vitro study. Future studies have to assess the physiological relevance in vivo. WIDER IMPLICATIONS OF THE FINDINGS: These findings indicate that the fertilization process is orchestrated by multiple oviductal CatSper agonists that act in concert to control the behavior of sperm. Moreover, our results substantiate the concerns regarding the negative impact of EDCs on male reproductive health. So far, safety thresholds like the "No Observed Adverse Effect Level (NOAEL)" or "No Observed Effect Concentration (NOEC)" are set for individual EDCs. Our finding that EDCs act synergistically in human sperm challenges the validity of this procedure. STUDY FUNDING/COMPETING INTEREST(S): This work was supported by the German Research Foundation (SFB 645; CRU326), the Cells-in-Motion (CiM) Cluster of Excellence, Münster, (FF-2016-17), the 'Innovative Medical Research' of the University of Münster Medical School (BR121507), an EDMaRC research grant from the Kirsten and Freddy Johansen's Foundation, and the Innovation Fund Denmark (InnovationsFonden; 14-2013-4). The authors have no competing financial interests.
KW - CatSper
KW - Combined drug actions
KW - Curveshift analysis
KW - Endocrine disrupting chemicals
KW - Human sperm
KW - Isobolographic analysis
KW - Progesterone
KW - Prostaglandins
U2 - 10.1093/humrep/dey275
DO - 10.1093/humrep/dey275
M3 - Journal article
C2 - 30189007
AN - SCOPUS:85055840931
VL - 33
SP - 1915
EP - 1923
JO - Human Reproduction
JF - Human Reproduction
SN - 0268-1161
IS - 10
ER -
ID: 209547059