title: Disruption of the NF-κB/NLRP3 connection by melatonin requires retinoid-related orphan receptor-α and blocks the septic response in mice.
abstract: We determined the NF-κB- and NOD-like receptor (NLR)P3-dependent molecular mechanisms involved in sepsis and evaluated the role of retinoid-related orphan receptor (ROR)-α in melatonin's anti-inflammatory actions. Western blot, RT-PCR, ELISA, and spectrophotometric analysis revealed that NF-κB and NLRP3 closely interact, leading to proinflammatory and pro-oxidant status in heart tissue of septic C57BL/6J mice. Moreover, mitochondrial oxygen consumption was reduced by 80% in septic mice. In vivo and in vitro analysis showed that melatonin administration blunts NF-κB transcriptional activity through a sirtuin1-dependent NF-κB deacetylation in septic mice. Melatonin also decreased NF-κB-dependent proinflammatory response and restored redox balance and mitochondrial homeostasis, thus inhibiting the NLRP3 inflammasome. In an important finding, the inhibition of NF-κB by melatonin, but not that of NLRP3, was blunted in RORα (sg/sg) mice, indicating that functional RORα transcription factor is necessary for the initiation of the innate immune response against inflammation. Our results are evidence of the NF-κB/NLRP3 connection during sepsis and identify NLRP3 as a novel molecular target for melatonin. The multiple molecular targets of melatonin in this study explain its potent anti-inflammatory efficacy against systemic innate immune activation and herald a promising therapeutic application for melatonin in the treatment of sepsis.
authors.affiliation: *Instituto de Biotecnología, Centro de Investigación Biomédica, Parque Tecnológico de Ciencias de la Salud, and Departamento de Fisiología, Facultad de Medicina, Universidad de Granada, Granada, Spain; and Unidad de Gestión Clínica de Laboratorios, Hospital Universitario San Cecilio, Granada, Spain.
authors.forename: José A
authors.initials: JA
authors.lastname: García
authors.affiliation: *Instituto de Biotecnología, Centro de Investigación Biomédica, Parque Tecnológico de Ciencias de la Salud, and Departamento de Fisiología, Facultad de Medicina, Universidad de Granada, Granada, Spain; and Unidad de Gestión Clínica de Laboratorios, Hospital Universitario San Cecilio, Granada, Spain.
authors.forename: Huayqui
authors.initials: H
authors.lastname: Volt
authors.affiliation: *Instituto de Biotecnología, Centro de Investigación Biomédica, Parque Tecnológico de Ciencias de la Salud, and Departamento de Fisiología, Facultad de Medicina, Universidad de Granada, Granada, Spain; and Unidad de Gestión Clínica de Laboratorios, Hospital Universitario San Cecilio, Granada, Spain.
authors.forename: Carmen
authors.initials: C
authors.lastname: Venegas
authors.affiliation: *Instituto de Biotecnología, Centro de Investigación Biomédica, Parque Tecnológico de Ciencias de la Salud, and Departamento de Fisiología, Facultad de Medicina, Universidad de Granada, Granada, Spain; and Unidad de Gestión Clínica de Laboratorios, Hospital Universitario San Cecilio, Granada, Spain.
authors.forename: Carolina
authors.initials: C
authors.lastname: Doerrier
authors.affiliation: *Instituto de Biotecnología, Centro de Investigación Biomédica, Parque Tecnológico de Ciencias de la Salud, and Departamento de Fisiología, Facultad de Medicina, Universidad de Granada, Granada, Spain; and Unidad de Gestión Clínica de Laboratorios, Hospital Universitario San Cecilio, Granada, Spain.
authors.forename: Germaine
authors.initials: G
authors.lastname: Escames
authors.affiliation: *Instituto de Biotecnología, Centro de Investigación Biomédica, Parque Tecnológico de Ciencias de la Salud, and Departamento de Fisiología, Facultad de Medicina, Universidad de Granada, Granada, Spain; and Unidad de Gestión Clínica de Laboratorios, Hospital Universitario San Cecilio, Granada, Spain.
authors.forename: Luis C
authors.initials: LC
authors.lastname: López
authors.affiliation: *Instituto de Biotecnología, Centro de Investigación Biomédica, Parque Tecnológico de Ciencias de la Salud, and Departamento de Fisiología, Facultad de Medicina, Universidad de Granada, Granada, Spain; and Unidad de Gestión Clínica de Laboratorios, Hospital Universitario San Cecilio, Granada, Spain dacuna@ugr.es.
authors.forename: Darío
authors.initials: D
authors.lastname: Acuña-Castroviejo
mesh_terms: D000818:Animals; D002352:Carrier Proteins / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D007113:Immunity, Innate / Q000187:drug effects* / Q000235:genetics; D008550:Melatonin / Q000494:pharmacology*; D051379:Mice; D008822:Mice, Transgenic; D016328:NF-kappa B / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D000071199:NLR Family, Pyrin Domain-Containing 3 Protein; D057094:Nuclear Receptor Subfamily 1, Group F, Member 1 / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D010084:Oxidation-Reduction / Q000187:drug effects; D018805:Sepsis / Q000235:genetics / Q000276:immunology / Q000378:metabolism* / Q000473:pathology
chemical_list: D002352:Carrier Proteins; D016328:NF-kappa B; D000071199:NLR Family, Pyrin Domain-Containing 3 Protein; C492716:Nlrp3 protein, mouse; D057094:Nuclear Receptor Subfamily 1, Group F, Member 1; C539739:Rora protein, mouse; D008550:Melatonin
keywords: bmal1; inflammasome; innate immunity; oxidative stress; sirtuin-1