title: Vitellogenins increase stress resistance of Caenorhabditis elegans after Photorhabdus luminescens infection depending on the steroid-signaling pathway.
abstract: Resistance against environmental stress is a crucial factor in determining the lifespan of organisms. A central role herein has been recently attributed to the transport and storage of lipids with the vitellogenin family emerging as a potential key factor. Here we show that the knockdown of one out of five functional vitellogenin genes, encoding apolipoprotein B homologues, results in a reduced survival of the nematode Caenorhabditis elegans at 37 °C subsequent to infection with the bacterial pathogen Photorhabdus luminescens. An active steroid-signaling pathway, including supply of cholesterol by vitellogenins, steroid ligand formation by the cytochrome P450 dependent DAF-9, and activation of the nuclear hormone receptor DAF-12, in the presence of pathogenic bacteria was associated with reduced nuclear translocation of the forkhead transcription factor DAF-16 and increased antioxidative capacity. Taken together, the study provides functional evidence for a crucial role of vitellogenins and the steroid-signaling pathway in determination of resistance against bacteria.
authors.affiliation: Molecular Nutrition Research, Interdisciplinary Research Center, Justus-Liebig-University of Giessen, Heinrich-Buff-Ring 26-32, D-35392 Giessen, Germany.
authors.forename: Malaika
authors.initials: M
authors.lastname: Fischer
authors.forename: Charlotte
authors.initials: C
authors.lastname: Regitz
authors.forename: Rebecca
authors.initials: R
authors.lastname: Kull
authors.forename: Michael
authors.initials: M
authors.lastname: Boll
authors.forename: Uwe
authors.initials: U
authors.lastname: Wenzel
mesh_terms: D000818:Animals; D017173:Caenorhabditis elegans / Q000235:genetics / Q000276:immunology / Q000378:metabolism / Q000502:physiology*; D055785:Gene Knockdown Techniques; D016905:Gram-Negative Bacterial Infections / Q000276:immunology*; D020637:Photorhabdus / Q000276:immunology*; D015398:Signal Transduction; D013256:Steroids / Q000378:metabolism*; D013312:Stress, Physiological; D016019:Survival Analysis; D013696:Temperature; D014819:Vitellogenins / Q000235:genetics / Q000378:metabolism*
chemical_list: D013256:Steroids; D014819:Vitellogenins
keywords: Antioxidative defense; Intestinal innate immunity; Lipid transport; Pathogen resistance; Steroidal-signaling; Vitellogenins