title: Lipocalin-type prostaglandin D synthase protects against oxidative stress-induced neuronal cell death.
abstract: L-PGDS [lipocalin-type PGD (prostaglandin D) synthase] is a dual-functional protein, acting as a PGD2-producing enzyme and a lipid transporter. L-PGDS is a member of the lipocalin superfamily and can bind a wide variety of lipophilic molecules. In the present study we demonstrate the protective effect of L-PGDS on H2O2-induced apoptosis in neuroblastoma cell line SH-SY5Y. L-PGDS expression was increased in H2O2-treated neuronal cells, and the L-PGDS level was highly associated with H2O2-induced apoptosis, indicating that L-PGDS protected the neuronal cells against H2O2-mediated cell death. A cell viability assay revealed that L-PGDS protected against H2O2-induced cell death in a concentration-dependent manner. Furthermore, the titration of free thiols in H2O2-treated L-PGDS revealed that H2O2 reacted with the thiol of Cys65 of L-PGDS. The MALDI-TOF (matrix-assisted laser-desorption ionization-time-of-flight)-MS spectrum of H2O2-treated L-PGDS showed a 32 Da increase in the mass relative to that of the untreated protein, showing that the thiol was oxidized to sulfinic acid. The binding affinities of oxidized L-PGDS for lipophilic molecules were comparable with those of untreated L-PGDS. Taken together, these results demonstrate that L-PGDS protected against neuronal cell death by scavenging reactive oxygen species without losing its ligand-binding function. The novel function of L-PGDS could be useful for the suppression of oxidative stress-mediated neurodegenerative diseases.
authors.affiliation: Laboratory of Biological Macromolecules, Graduate School of Life and Environmental Sciences, Osaka Prefecture University, Sakai, Osaka 599-8531, Japan.
authors.forename: Ayano
authors.initials: A
authors.lastname: Fukuhara
authors.forename: Mao
authors.initials: M
authors.lastname: Yamada
authors.forename: Ko
authors.initials: K
authors.lastname: Fujimori
authors.forename: Yuya
authors.initials: Y
authors.lastname: Miyamoto
authors.forename: Toshihide
authors.initials: T
authors.lastname: Kusumoto
authors.forename: Hidemitsu
authors.initials: H
authors.lastname: Nakajima
authors.forename: Takashi
authors.initials: T
authors.lastname: Inui
mesh_terms: D020816:Amino Acid Motifs; D017209:Apoptosis; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D003198:Computer Simulation; D003545:Cysteine / Q000737:chemistry; D019610:Cytoprotection; D053938:DNA Fragmentation; D006801:Humans; D006861:Hydrogen Peroxide / Q000737:chemistry / Q000494:pharmacology; D019746:Intramolecular Oxidoreductases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D054834:Lipocalins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D008958:Models, Molecular; D016297:Mutagenesis, Site-Directed; D009474:Neurons / Q000187:drug effects / Q000201:enzymology / Q000502:physiology*; D016877:Oxidants / Q000737:chemistry / Q000494:pharmacology; D010084:Oxidation-Reduction; D018384:Oxidative Stress; D017434:Protein Structure, Tertiary; D040681:Structural Homology, Protein; D014364:Tryptophan / Q000737:chemistry
chemical_list: D054834:Lipocalins; D016877:Oxidants; D014364:Tryptophan; D006861:Hydrogen Peroxide; D019746:Intramolecular Oxidoreductases; C022466:prostaglandin R2 D-isomerase; D003545:Cysteine