title: Soluble products of Escherichia coli induce mitochondrial dysfunction-related sperm membrane lipid peroxidation which is prevented by lactobacilli.
abstract: Unidentified soluble factors secreted by E. coli, a frequently isolated microorganism in genitourinary infections, have been reported to inhibit mitochondrial membrane potential (ΔΨm), motility and vitality of human spermatozoa. Here we explore the mechanisms involved in the adverse impact of E. coli on sperm motility, focusing mainly on sperm mitochondrial function and possible membrane damage induced by mitochondrial-generated reactive oxygen species (ROS). Furthermore, as lactobacilli, which dominate the vaginal ecosystem of healthy women, have been shown to exert anti-oxidant protective effects on spermatozoa, we also evaluated whether soluble products from these microorganisms could protect spermatozoa against the effects of E. coli. We assessed motility (by computer-aided semen analysis), ΔΨm (with JC-1 dye by flow cytometry), mitochondrial ROS generation (with MitoSOX red dye by flow cytometry) and membrane lipid-peroxidation (with the fluorophore BODIPY C11 by flow cytometry) of sperm suspensions exposed to E. coli in the presence and in the absence of a combination of 3 selected strains of lactobacilli (L. brevis, L. salivarius, L. plantarum). A Transwell system was used to avoid direct contact between spermatozoa and microorganisms. Soluble products of E. coli induced ΔΨm loss, mitochondrial generation of ROS and membrane lipid-peroxidation, resulting in motility loss. Soluble factors of lactobacilli prevented membrane lipid-peroxidation of E. coli-exposed spermatozoa, thus preserving their motility. In conclusion, sperm motility loss by soluble products of E. coli reflects a mitochondrial dysfunction-related membrane lipid-peroxidation. Lactobacilli could protect spermatozoa in the presence of vaginal disorders, by preventing ROS-induced membrane damage.
authors.affiliation: Andrology Unit, Department of Life, Health and Environment Sciences, University of L'Aquila, L'Aquila, Italy ; San Raffaele Sulmona Institute, Sulmona, Italy.
authors.forename: Arcangelo
authors.initials: A
authors.lastname: Barbonetti
authors.affiliation: Andrology Unit, Department of Life, Health and Environment Sciences, University of L'Aquila, L'Aquila, Italy.
authors.forename: Maria Rosaria Caterina
authors.initials: MR
authors.lastname: Vassallo
authors.affiliation: Immunopathology Laboratory, Department of Life, Health and Environment Sciences, University of L'Aquila, L'Aquila, Italy.
authors.forename: Benedetta
authors.initials: B
authors.lastname: Cinque
authors.affiliation: Andrology Unit, Department of Life, Health and Environment Sciences, University of L'Aquila, L'Aquila, Italy.
authors.forename: Silvia
authors.initials: S
authors.lastname: Filipponi
authors.affiliation: Institute of Microbiology, University 'La Sapienza', Rome, Italy.
authors.forename: Paola
authors.initials: P
authors.lastname: Mastromarino
authors.affiliation: Immunopathology Laboratory, Department of Life, Health and Environment Sciences, University of L'Aquila, L'Aquila, Italy.
authors.forename: Maria Grazia
authors.initials: MG
authors.lastname: Cifone
authors.affiliation: Andrology Unit, Department of Life, Health and Environment Sciences, University of L'Aquila, L'Aquila, Italy.
authors.forename: Sandro
authors.initials: S
authors.lastname: Francavilla
authors.affiliation: Andrology Unit, Department of Life, Health and Environment Sciences, University of L'Aquila, L'Aquila, Italy.
authors.forename: Felice
authors.initials: F
authors.lastname: Francavilla
mesh_terms: D001685:Biological Factors / Q000737:chemistry / Q000494:pharmacology*; D019610:Cytoprotection / Q000187:drug effects; D004926:Escherichia coli / Q000737:chemistry* / Q000502:physiology; D005260:Female; D006801:Humans; D007778:Lactobacillus / Q000737:chemistry / Q000502:physiology*; D015227:Lipid Peroxidation / Q000187:drug effects*; D008297:Male; D053078:Membrane Potential, Mitochondrial / Q000187:drug effects; D008928:Mitochondria / Q000187:drug effects / Q000378:metabolism*; D051336:Mitochondrial Membranes / Q000187:drug effects; D017382:Reactive Oxygen Species / Q000378:metabolism; D055101:Semen Analysis; D013094:Spermatozoa / Q000187:drug effects* / Q000382:microbiology / Q000502:physiology / Q000648:ultrastructure
chemical_list: D001685:Biological Factors; D017382:Reactive Oxygen Species