Identification of a Testicular Odorant Receptor Mediating Human Sperm Chemotaxis

Abstract

Although it has been known for some time that olfactory receptors (ORs) reside in spermatozoa, the function of these ORs is unknown. Here, we identified, cloned, and functionally expressed a previously undescribed human testicular OR, hOR17-4. With the use of ratiofluorometric imaging, Ca2+ signals were induced by a small subset of applied chemical stimuli, establishing the molecular receptive fields for the recombinantly expressed receptor in human embryonic kidney (HEK) 293 cells and the native receptor in human spermatozoa. Bourgeonal was a powerful agonist for both recombinant and native receptor types, as well as a strong chemoattractant in subsequent behavioral bioassays. In contrast, undecanal was a potent OR antagonist to bourgeonal and related compounds. Taken together, these results indicate that hOR17-4 functions in human sperm chemotaxis and may be a critical component of the fertilization process.

Possible ability of bovine follicular fluid to attract migrating bull spermatozoa

“…In the human,16, 21, 22, 23 rabbit,10 and mouse,15 sperm chemotaxis to the follicular fluid and egg‐related material has been observed, but the mechanism of sperm chemotaxis is not sufficiently understood. In this study, it was investigated whether bull sperm can be attracted to the BFF.…”

Le chimiotactisme du spermatozoïde est régulé par la fixation de la progestérone sur le canal calcique CATSPER

“…Plusieurs voies de signalisation ont été décrites comme participant au chimiotactisme du spermatozoïde chez les mammifères. La présence de récepteurs olfactifs sur le spermatozoïde a été démontrée et leur activation par des molécules odorantes comme le « bourgeonal » est capable de modifier la trajectoire des spermatozoïdes [14]. La voie de signalisation en aval du récepteur active classiquement une protéine G, puis l'adényl-cyclase de l'ordre de 100 pM, le maximum de potentialisation étant atteint pour des concentrations de l'ordre 100 nM.…”

Olfaction in the kidney: ‘smelling’ gut microbial metabolites

“…2009) and the chemotaxis of sperm (Spehr et al . 2003), and we have recently shown that olfactory receptors are expressed in the kidney. One of the novel renal G‐protein‐coupled receptors we are interested in is olfactory receptor 78 (Olfr78; Pluznick et al .…”