title: Heat Sensing Receptor TRPV1 Is a Mediator of Thermotaxis in Human Spermatozoa.
abstract: The molecular bases of sperm thermotaxis, the temperature-oriented cell motility, are currently under investigation. Thermal perception relies on a subclass of the transient receptor potential [TRP] channels, whose member TRPV1 is acknowledged as the heat sensing receptor. Here we investigated the involvement of TRPV1 in human sperm thermotaxis. We obtained semen samples from 16 normozoospermic subjects attending an infertility survey programme, testis biopsies from 6 patients with testicular germ cell cancer and testis fine needle aspirates from 6 patients with obstructive azoospermia undergoing assisted reproductive technologies. Expression of TRPV1 mRNA was assessed by RT-PCR. Protein expression of TRPV1 was determined by western blot, flow cytometry and immunofluorescence. Sperm motility was assessed by Sperm Class Analyser. Acrosome reaction, apoptosis and intracellular-Ca2+ content were assessed by flow cytometry. We found that TRPV1 mRNA and protein were highly expressed in the testis, in both Sertoli cells and germ-line cells. Moreover, compared to no-gradient controls at 31°C or 37°C (Ctrl 31°C and Ctrl 37°C respectively), sperm migration towards a temperature gradient of 31-37°C (T gradient) in non-capacitated conditions selected a higher number of cells (14,9 ± 4,2×106 cells T gradient vs 5,1± 0,3×106 cells Ctrl 31°C and 5,71±0,74×106 cells Ctrl 37°C; P = 0,039). Capacitation amplified the migrating capability towards the T gradient. Sperms migrated towards the T gradient showed enriched levels of both TRPV1 protein and mRNA. In addition, sperm cells were able to migrate toward a gradient of capsaicin, a specific agonist of TRPV1, whilst capsazepine, a specific agonist of TRPV1, blocked this effect. Finally, capsazepine severely blunted migration towards T gradient without abolishing. These results suggest that TRPV1 may represent a facilitating mediator of sperm thermotaxis.
authors.affiliation: Department of Medicine, Unit of Andrology and Reproductive Medicine, University of Padova, Via Giustiniani, Padova, Italy.
authors.forename: Luca
authors.initials: L
authors.lastname: De Toni
authors.affiliation: Department of Medicine, Unit of Andrology and Reproductive Medicine, University of Padova, Via Giustiniani, Padova, Italy.
authors.forename: Andrea
authors.initials: A
authors.lastname: Garolla
authors.affiliation: Department of Medicine, Unit of Andrology and Reproductive Medicine, University of Padova, Via Giustiniani, Padova, Italy.
authors.forename: Massimo
authors.initials: M
authors.lastname: Menegazzo
authors.affiliation: Department of Medicine, Unit of Andrology and Reproductive Medicine, University of Padova, Via Giustiniani, Padova, Italy.
authors.forename: Sabina
authors.initials: S
authors.lastname: Magagna
authors.affiliation: Department of Medicine, Unit of Andrology and Reproductive Medicine, University of Padova, Via Giustiniani, Padova, Italy.
authors.forename: Andrea
authors.initials: A
authors.lastname: Di Nisio
authors.affiliation: Department of Medicine, Unit of Andrology and Reproductive Medicine, University of Padova, Via Giustiniani, Padova, Italy.|IRCCS-Istituto Oncologico Veneto [IOV], Via Gattamelata, Padova, Italy.
authors.forename: Iva
authors.initials: I
authors.lastname: Šabović
authors.affiliation: Department of Medicine, Unit of Andrology and Reproductive Medicine, University of Padova, Via Giustiniani, Padova, Italy.
authors.forename: Maria Santa
authors.initials: MS
authors.lastname: Rocca
authors.affiliation: Department of Medicine, University of Padova, Via Giustiniani, Padova, Italy.|Venetian Institute of Molecular Medicine, Via Orus 2, Padova, Italy.
authors.forename: Valentina
authors.initials: V
authors.lastname: Scattolini
authors.affiliation: Department of Physics and Astronomy "G. Galilei", University of Padova, Via Marzolo 8, Padova, Italy.
authors.forename: Andrea
authors.initials: A
authors.lastname: Filippi
authors.affiliation: Department of Medicine, Unit of Andrology and Reproductive Medicine, University of Padova, Via Giustiniani, Padova, Italy.
authors.forename: Carlo
authors.initials: C
authors.lastname: Foresta
mesh_terms: D000328:Adult; D053713:Azoospermia / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D002211:Capsaicin / Q000031:analogs & derivatives / Q000494:pharmacology; D006801:Humans; D007248:Infertility, Male / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D008297:Male; D009373:Neoplasms, Germ Cell and Embryonal / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D013081:Sperm Motility; D013094:Spermatozoa / Q000187:drug effects / Q000378:metabolism / Q000502:physiology*; D050916:TRPV Cation Channels / Q000235:genetics* / Q000378:metabolism; D000071442:Taxis Response / Q000187:drug effects; D013736:Testicular Neoplasms / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D055815:Young Adult
chemical_list: D050916:TRPV Cation Channels; C494482:TRPV1 protein, human; C071423:capsazepine; D002211:Capsaicin