TRPM8 in mouse sperm detects temperature changes and may influence the acrosome reaction

Abstract

Changes in the concentration of intracellular Ca(2+) ([Ca(2+) ]i) trigger and/or regulate principal sperm functions during fertilization, such as motility, capacitation, and the acrosome reaction (AR). Members of the large TRP channel family participate in a variety of Ca(2+) -dependent cell signaling processes. The eight TRPM channel members constitute one of the seven groups belonging to this family. Here we document using RT-PCR experiments the presence of Trpm2, 4, 7, and 8 in mouse spermatogenic cells. Trpm8 transcription is up-regulated after day 30. The localization of TRPM8 protein in mouse sperm was confirmed by immunocytochemistry and Western blots. Patch clamp recordings in testicular mouse sperm revealed TRPM8 agonist (menthol and icilin) activated currents sensitive to TRPM8 inhibitors N-(4-t-Butylphenyl)-4-(3-Chloropyridin-2-yl)tetrahydropyrazine-1(2H)-carboxamide (BCTC) and capsazepine. These findings are consistent with the presence of functional TRPM8 in mouse sperm. Furthermore, menthol induced a [Ca(2+) ]i increase and the AR in these cells, that were inhibited by capsazepine (20 µM) and BCTC (1.6 µM). Notably, the progesterone and zona pellucida-induced AR was significantly (>40%) inhibited by BCTC and capsazepine, suggesting the possible participation of TRPM8 channels in this reaction. TRPM family members present in sperm could be involved in other important signaling events, such as thermotaxis, chemotaxis, and mechanosensory transduction.

Cysteine-rich secretory protein 4 is an inhibitor of transient receptor potential M8 with a role in establishing sperm function

“…As shown previously, menthol addition resulted in the activation of current relative to the control (27), demonstrating TRPM8 stimulation ( Fig. 3 A, B, and D).…”

“…Several TRP channels have been localized to mouse or human sperm, including TRPC1-6 and TRPM8 (25,29,30). Given our recent data demonstrating the localization and functional analysis of TRMP8 on mouse sperm (27) and the considerable similarity of the current data to earlier investigations (26), we chose to analyze the affect of CRISP4 on TRPM8 in the first instance.…”

“…These data raise the potential for CRISP4, via the regulation of ion channels, to impact upon several aspects of sperm function. In the present study, we chose to focus on the TRP channel subset of Ca 2+ conducting channels in mammalian sperm (25)(26)(27).…”

Cl− Channels and Transporters in Sperm Physiology

“…Additionally, a voltage-sensitive H + channel involved in the intracellular pH (pH i ) regulation in human sperm and less importantly in mouse sperm (Kirichok and Lishko 2011 ), and ATP-gated channels of the purinergic family, P2X2, in mouse epididymal sperm have been recorded (Navarro et al 2011 ). Ionic currents with properties consistent with TRPM8 channels were recorded in testicular sperm Martinez-Lopez et al 2011 ). Intracellular Ca 2+ concentration [Ca 2+ ] i imaging experiments at different temperatures and membrane potential ( E m ) measurements suggested TRPM8-like channels are present in more mature mouse and human sperm (De Blas et al 2009 ;Martinez-Lopez et al 2011 ).…”

“…Ionic currents with properties consistent with TRPM8 channels were recorded in testicular sperm Martinez-Lopez et al 2011 ). Intracellular Ca 2+ concentration [Ca 2+ ] i imaging experiments at different temperatures and membrane potential ( E m ) measurements suggested TRPM8-like channels are present in more mature mouse and human sperm (De Blas et al 2009 ;Martinez-Lopez et al 2011 ).…”