Sperm cholesterol content modifies sperm function and trpv1‐mediated sperm migration

Transient receptor potential channels‐vanilloid receptor 1 (TRPV1) regulates thermotaxis in sperm‐oriented motility. We investigated the role of membrane cholesterol (Chol) on TRPV1‐ mediated human sperm migration. Semen samples were obtained from five normozoospemic healthy volunteers. Sperm membrane Chol content, quantified by liquid chromatography‐mass spectrometry, was modified by incubating cells with 2‐hydroxypropyl‐ß‐cyclodextrin (CD) or the complex between CD and Chol (CD:Chol). The effect on sperm migration on a 10 μM capsaicin gradient (CPS), a TRPV1 agonist, was then investigated. Motility parameters were evaluated by Sperm Class Analyser. Intracellular calcium concentration and acrosome reaction were measured by staining with calcium orange and FITC‐conjugated anti‐CD46 antibody, respectively. TRPV1‐ Chol interaction was modelled by computational molecular‐modelling (MM). CD and CD:Chol, respectively, reduced and increased membrane Chol content in a dose‐dependent manner, resulting in a dose‐dependent increase and reduction of sperm migration in a CPS gradient. MM confirmed a specific interaction of Chol with a TRPV1 domain that appeared precluded to the Chol epimer epicholesterol (Epi‐Chol). Accordingly, CD:Epi‐Chol was significantly less efficient than CD:Chol, in reducing sperm migration under CPS gradient. Chol inhibits TRPV1‐mediated sperm function by directly interacting with a consensus sequence of the receptor.