title: NOX5 in human spermatozoa: expression, function, and regulation.
abstract: Physiological and pathological processes in spermatozoa involve the production of reactive oxygen species (ROS), but the identity of the ROS-producing enzyme system(s) remains a matter of speculation. We provide the first evidence that NOX5 NADPH oxidase is expressed and functions in human spermatozoa. Immunofluorescence microscopy detected NOX5 protein in both the flagella/neck region and the acrosome. Functionally, spermatozoa exposed to calcium ionophore, phorbol ester, or H(2)O(2) exhibited superoxide anion production, which was blocked by addition of superoxide dismutase, a Ca(2+) chelator, or inhibitors of either flavoprotein oxidases (diphenylene iododonium) or NOX enzymes (GKT136901). Consistent with our previous overexpression studies, we found that H(2)O(2)-induced superoxide production by primary sperm cells was mediated by the non-receptor tyrosine kinase c-Abl. Moreover, the H(V)1 proton channel, which was recently implicated in spermatozoa motility, was required for optimal superoxide production by spermatozoa. Immunoprecipitation experiments suggested an interaction among NOX5, c-Abl, and H(V)1. H(2)O(2) treatment increased the proportion of motile sperm in a NOX5-dependent manner. Statistical analyses showed a pH-dependent correlation between superoxide production and enhanced sperm motility. Collectively, our findings show that NOX5 is a major source of ROS in human spermatozoa and indicate a role for NOX5-dependent ROS generation in human spermatozoa motility.
authors.affiliation: Department of Molecular Biophysics and Physiology, Rush University Medical Center, Chicago, Illinois 60612, USA.
authors.forename: Boris
authors.initials: B
authors.lastname: Musset
authors.forename: Robert A
authors.initials: RA
authors.lastname: Clark
authors.forename: Thomas E
authors.initials: TE
authors.lastname: DeCoursey
authors.forename: Gabor L
authors.initials: GL
authors.lastname: Petheo
authors.forename: Miklos
authors.initials: M
authors.lastname: Geiszt
authors.forename: Yumin
authors.initials: Y
authors.lastname: Chen
authors.forename: John E
authors.initials: JE
authors.lastname: Cornell
authors.forename: Carlton A
authors.initials: CA
authors.lastname: Eddy
authors.forename: Robert G
authors.initials: RG
authors.lastname: Brzyski
authors.forename: Amina
authors.initials: A
authors.lastname: El Jamali
mesh_terms: D002460:Cell Line; D015971:Gene Expression Regulation, Enzymologic; D006801:Humans; D008297:Male; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D000074664:NADPH Oxidase 5; D019255:NADPH Oxidases / Q000235:genetics / Q000378:metabolism*; D013081:Sperm Motility; D013094:Spermatozoa / Q000166:cytology / Q000201:enzymology* / Q000378:metabolism; D013481:Superoxides / Q000378:metabolism*
chemical_list: D008565:Membrane Proteins; D013481:Superoxides; D000074664:NADPH Oxidase 5; D019255:NADPH Oxidases; C431571:NOX5 protein, human