title: Interferon Gamma potentiates the injury caused by MPP(+) on SH-SY5Y cells, which is attenuated by the nitric oxide synthases inhibition.
abstract: This study examined whether the cytokine interferon (IFN) gamma plays a role in the injury of SH-SY5Y cells caused by MPP(+) (1-methyl-4-phenylpyridinium). First of all, IFN-gamma sensitized cells to the neurotoxin MPP(+), as determined by MTT (3-(4,5-dimethylthiazol-2-y1)-2,5-diphenyltetrazolium bromide) assay. MPP(+)-injured cells showed higher reactive oxygen species (ROS) levels, which was reinforced by IFN-gamma. The injury triggered a marked expression of the neuronal NOS (nNOS) enzyme. L-NAME [N(ω)-nitro-L-arginine methyl ester, a non-specific NOS inhibitor] reestablished the cell viability after IFN-gamma challenging, and recovered cells from MPP(+) injury (95.0 vs. 84.7 %; P < 0.05). Seven-NI (7-nitroindazole, a nNOS inhibitor) protected cells against the injury by MPP(+) co-administered with IFN-gamma. Both inhibitors restrained the apoptosis of SH-SY5Y cells caused by MPP(+)/IFN-gamma. Regarding oxidative stress, L-NAME and 7-NI attenuated the increase in ROS levels caused by MPP(+) (45.3 or 48.4 vs. 87.9 %, P < 0.05). Indeed, L-NAME was more effective than 7-NI for reducing oxidative stress caused by MPP(+) under IFN-gamma exposition. The nNOS gene silencing by small-interfering RNAs recovered cells challenged by IFN-gamma (24 h), or MPP(+) (8 h). In conclusion, IFN-gamma sensitizes cells to MPP(+)-induced injury, also causing an increase in ROS levels. Pretreating cells with L-NAME or 7-NI reverts both the oxidative stress and apoptosis triggered by the neurotoxin MPP(+). Taking together, our data reinforce that IFN-gamma and NOS enzymes play a role in oxidative stress and dopaminergic cell death triggered by MPP(+).
authors.affiliation: Laboratório de Tecnologias para Terapia Gênica, ASS 128, ICC Sul. Universidade de Brasília - UnB, Campus Darcy Ribeiro, FAV, Brasília, DF, 70910-970, Brazil.
authors.forename: Simoneide S
authors.initials: SS
authors.lastname: Titze-de-Almeida
authors.forename: Cátia Faria
authors.initials: CF
authors.lastname: Lustosa
authors.forename: Camila Hillesheim
authors.initials: CH
authors.lastname: Horst
authors.forename: Elaine Del
authors.initials: ED
authors.lastname: Bel
authors.forename: Ricardo
authors.initials: R
authors.lastname: Titze-de-Almeida
mesh_terms: D017209:Apoptosis / Q000235:genetics; D045744:Cell Line, Tumor; D006801:Humans; D007371:Interferon-gamma / Q000502:physiology*; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors*; D034741:RNA, Small Interfering; D060888:Real-Time Polymerase Chain Reaction; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D034741:RNA, Small Interfering; D007371:Interferon-gamma; D019001:Nitric Oxide Synthase