Cl- is required for HCO3- entry necessary for sperm capacitation in guinea pig: involvement of a Cl-/HCO3- exchanger (SLC26A3) and CFTR.
Our previous study demonstrated the involvement of cystic fibrosis transmembrane conductance regulator (CFTR) in transporting bicarbonate that is necessary for sperm capacitation; however, whether its involvement is direct or indirect remains unclear. The present study investigated the possibility of a Cl-/HCO3- exchanger (solute carrier family 26, number 3 [SLC26A3]) operating with CFTR during guinea pig sperm capacitation. Incubating sperm in media with various concentrations of Cl- resulted in varied percentages of capacitated sperm in a concentration-dependent manner. Depletion of Cl-, even in the presence of HCO3-, abolished sperm capacitation and vice versa, indicating the involvement of both anions in the process. Capacitation-associated HCO3--dependent events, including increased intracellular pH, cAMP production, and protein tyrosine phosphorylation, also depend on Cl- concentrations. Similar Cl- dependence and inhibitor sensitivity were observed for sperm-hyperactivated motility and for sperm-egg fusion. The expression and localization of CFTR and SLC26A3 were demonstrated using immunostaining and Western blot analysis. Taken together, our results indicate that Cl- is required for the entry of HCO3- that is necessary for sperm capacitation, implicating the involvement of SLC26A3 in transporting HCO3-, with CFTR providing the recycling pathway for Cl-.
Chen
Wen Ying
WY
Unit of Reproductive Physiology, Institute of Reproductive Health, Zhejiang Academy of Medical Sciences, Hangzhou 310013, China.
Xu
Wen Ming
WM
Chen
Zhang Hui
ZH
Ni
Ya
Y
Yuan
Yu Ying
YY
Zhou
Si Chang
SC
Zhou
Wen Wei
WW
Tsang
Lai Ling
LL
Chung
Yiu Wa
YW
Höglund
Pia
P
Chan
Hsiao Chang
HC
Shi
Qi Xian
QX
D020101:Acrosome Reaction / Q000187:drug effects / Q000502:physiology; D000818:Animals; D017920:Antiporters / Q000037:antagonists & inhibitors / Q000378:metabolism*; D001639:Bicarbonates / Q000493:pharmacokinetics / Q000494:pharmacology*; D015153:Blotting, Western; D002712:Chlorides / Q000493:pharmacokinetics / Q000494:pharmacology*; D000242:Cyclic AMP / Q000378:metabolism; D019005:Cystic Fibrosis Transmembrane Conductance Regulator / Q000037:antagonists & inhibitors / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D005260:Female; D005455:Fluorescent Antibody Technique; D006168:Guinea Pigs; D006863:Hydrogen-Ion Concentration; D008297:Male; D013075:Sperm Capacitation / Q000187:drug effects / Q000502:physiology*; D013084:Sperm-Ovum Interactions / Q000502:physiology; D013094:Spermatozoa / Q000187:drug effects / Q000378:metabolism*; D000076988:Sulfate Transporters
D017920:Antiporters; D001639:Bicarbonates; D002712:Chlorides; C489860:Slc26a3 protein, mouse; D000076988:Sulfate Transporters; D019005:Cystic Fibrosis Transmembrane Conductance Regulator; D000242:Cyclic AMP