TRPM8 IN HUMAN SPERM.

TREVIÑO CL; DE BLAS GA; OCAMPO AY; SERRANO CJ; CASTELLANO LE; HERNÁNDEZ-GONZÁLEZ EO; CHIRINOS M; LARREA F; BELTRÁN C; DARSZON A

Holderness School, Holderness, New Hampshire. USA.

Congreso; Gordon Research Conference: Fertilization & Activation Of Development; 2009

Gordon Research Conference

The transient receptor potential channel (TRP) family includes more than 30 proteins; they participate in diverse Ca2+ dependent processes. TRPs are functionally diverse, involving thermal, chemical and mechanical transducers which modulate the concntration of intracellular Ca2+ ([Ca2+]i). Ca2+ triggers and/or regulates principal sperm functions during fertilization such as motility, capacitation and the acrosome reaction (AR). Tehe presence of the TRPM subfamily is sperm has not been explored. Here we document with RT-PCR experiments the presence of TRPM8 in human sperm. Western blot and immunocitochemistry confirmed the presence of this channel in these cells. We also examined the participation of TRPM8 in sperm functions using specific agonists (menthol and temperature) and antagonists (BCTC and capsazepine). First we evaluated sperm motility using a computer-aided sperm analysis sytem (CASA) and found that menthol (1 mM) did not significantly alter human sperm motility parameters. In contrast, menthol potently induced the AR in human sperm. This induction was inhibited about 70% by capsazepine (20 μM) and 80% by BCTC (1.6 μM). Consistently, menthol and a temperature decrease, they both induced [Ca2+]i increases in human sperm, while the TRPM8 antagonists, capsazepine (20 μM) and BCTC (1.6 μM) inhibited these changes. Progesterone and ZP3 are the natural AR inducers of human sperm; we explored the ability of TRPM8 antagonists to block this induction. Progesterone and ZP3-induced AR was only weakly inhibited by BCTC and capsazepine, suggesting TRPM8 induces the AR by a different signaling pathway and/or a possible involvement for this channel in other signaling events such as thermotaxis or chemotaxis.