title: DNA damage, RAD9 and fertility/infertility of Echinococcus granulosus hydatid cysts.
abstract: Hydatidosis, caused by the larval stage of the platyhelminth parasite Echinococcus granulosus, affects human and animal health. Hydatid fertile cysts are formed in intermediate hosts (human and herbivores) producing protoscoleces, the infective form to canines, at their germinal layers. Infertile cysts are also formed, but they are unable to produce protoscoleces. The molecular mechanisms involved in hydatid cysts fertility/infertility are unknown. Nevertheless, previous work from our laboratory has suggested that apoptosis is involved in hydatid cyst infertility and death. On the other hand, fertile hydatid cysts can resist oxidative damage due to reactive oxygen and nitrogen species. On these foundations, we have postulated that when oxidative damage of DNA in the germinal layers exceeds the capability of DNA repair mechanisms, apoptosis is triggered and hydatid cysts infertility occurs. We describe a much higher percentage of nuclei with oxidative DNA damage in dead protoscoleces and in the germinal layer of infertile cysts than in fertile cysts, suggesting that DNA repair mechanisms are active in fertile cysts. rad9, a conserved gene, plays a key role in cell cycle checkpoint modulation and DNA repair. We found that RAD9 of E. granulosus (EgRAD9) is expressed at the mRNA and protein levels. As it was found in other eukaryotes, EgRAD9 is hyperphosphorylated in response to DNA damage. Our results suggest that molecules involved in DNA repair in the germinal layer of fertile hydatid cysts and in protoscoleces, such as EgRAD9, may allow preserving the fertility of hydatid cysts in the presence of ROS and RNS.
authors.affiliation: Programa Disciplinario de Biología Celular y Molecular, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Santiago, Chile.
authors.forename: Gonzalo
authors.initials: G
authors.lastname: Cabrera
authors.forename: María Eugenia
authors.initials: ME
authors.lastname: Cabrejos
authors.forename: Alessandra Loureiro
authors.initials: AL
authors.lastname: Morassutti
authors.forename: Carolina
authors.initials: C
authors.lastname: Cabezón
authors.forename: Juana
authors.initials: J
authors.lastname: Orellana
authors.forename: Ulf
authors.initials: U
authors.lastname: Hellman
authors.forename: Arnaldo
authors.initials: A
authors.lastname: Zaha
authors.forename: Norbel
authors.initials: N
authors.lastname: Galanti
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism*; D004249:DNA Damage; D004260:DNA Repair; D004443:Echinococcosis; D048209:Echinococcus granulosus / Q000033:anatomy & histology / Q000502:physiology*; D005298:Fertility / Q000502:physiology*; D015801:Helminth Proteins / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D006861:Hydrogen Peroxide / Q000378:metabolism; D008958:Models, Molecular; D008969:Molecular Sequence Data; D016877:Oxidants / Q000378:metabolism; D010084:Oxidation-Reduction; D018384:Oxidative Stress; D010802:Phylogeny; D017434:Protein Structure, Tertiary; D017382:Reactive Oxygen Species / Q000378:metabolism; D016415:Sequence Alignment
chemical_list: D018797:Cell Cycle Proteins; D015801:Helminth Proteins; D016877:Oxidants; D017382:Reactive Oxygen Species; C069930:rad9 protein; D006861:Hydrogen Peroxide