Bicarbonate-Triggered In Vitro Capacitation of Boar Spermatozoa Conveys an Increased Relative Abundance of the Canonical Transient Receptor Potential Cation (TRPC) Channels 3, 4, 6 and 7 and of CatSper-gamma Subunit mRNA Transcripts

• Simple Summary The detection of sub-fertile boars has been a difficult task, and despite their prevalence being low, its impact is very significant because it implies economic drawbacks for artificial insemination (AI) centers and farms. Unfortunately, some crucial reproductive processes fall beyond the routine analysis performed in the porcine model, such as sperm capacitation, which is a necessary event for fertilization. A synergistic action of bicarbonate (HCO3-) with calcium (Ca2+) is needed to achieve capacitation. The transport of Ca2+ is mediated by CatSper channels and Canonical Transient Potential Channels (TRPC). We quantified mRNA transcripts of different subunits of CatSper (beta, gamma and delta) and TRPC (1, 3, 4, 6 and 7) before and after in vitro capacitation by HCO3- ions. Our results showed that in vitro capacitation using HCO3- increases the relative abundance of mRNA transcripts of almost all subunits of Ca2+ channels, except CatSper-delta and TRPC1, which were significantly reduced. More studies are needed to elucidate the specific roles of the TRPC channels at a physiological and functional level. Sperm capacitation is a stepwise complex biochemical process towards fertilization. It includes a crucial early calcium (Ca2+) transport mediated by CatSper channels and Canonical Transient Potential Channels (TRPC). We studied the relative abundance of mRNA transcripts changes of the CatSper beta, gamma and delta subunits and TRPC-channels 1, 3, 4, 6 and 7 in pig spermatozoa, after triggering in vitro capacitation by bicarbonate ions at levels present in vivo at the fertilization site. For this purpose, we analyzedfive5 ejaculate pools (from three fertile adult boars) before (control-fresh samples) and after in vitro exposure to capacitation conditions (37 mM NaHCO3, 2.25 mM CaCl2, 2 mM caffeine, 0.5% bovine serum albumin and 310 mM lactose) at 38 degrees C, 5% CO2 for 30 min. In vitro capacitation using bicarbonate elicits an increase in the relative abundance of mRNA transcripts of almost all studied Ca2+ channels, except CatSper-delta and TRPC1 (significantly reduced). These findings open new avenues of research to identify the specific role of each channel in boar sperm capacitation and elucidate the physiological meaning of the changes on sperm mRNA cargo.

Subject headings

NATURVETENSKAP  -- Biologi -- Biokemi och molekylärbiologi (hsv//swe)

NATURAL SCIENCES  -- Biological Sciences -- Biochemistry and Molecular Biology (hsv//eng)

Keyword

calcium channels; catSper subunits; TRPC; pig; capacitation

Publication and Content Type

ref (subject category)

art (subject category)