title: Interleukin 4 induces the apoptosis of mouse microglial cells by a caspase-dependent mechanism.
abstract: Microglial cells are resident macrophages in the central nervous system (CNS) and become activated in many pathological conditions. Activation of microglial cells results in reactive microgliosis, manifested by an increase in cell number in the affected CNS regions. The control of microgliosis may be important to prevent pathological damage to the brain. The type 2 cytokine IL-4 has been reported to be protective in brain inflammation. However, its effect on microglial cell survival was not well understood. In this study, we report a dual effect of IL-4 on the survival of mouse microglial cells. In a 6h short term culture, IL-4 reduced the death of microglial cells induced by staurosporine. In contrast, in long term treatment (more than 48h), IL-4 increased the apoptotic death of both primary mouse microglial cells and a microglial cell line N9. Mechanistic studies revealed that, in microglial cells, IL-4 increased the levels of cleaved caspase 3 and PARP, which is down-stream of activated caspase 3. In addition, IL-4 down regulated the autophagy and the antiapoptotic protein Bcl-xL in microglial cells. On the other hand, the pre-incubation of microglial cells with IL-4 for 24h, attenuated the cell death induced by the neurotoxic peptide amyloid beta 1-42 (Aβ42). Our observations demonstrate a novel function of IL-4 in regulating the survival of microglial cells, which may have important significance in reduction of undesired inflammatory responses in the CNS.
authors.affiliation: Centro de Investigaciones en Bioquimica Clinica e Inmunologia-CONICET, Departamento de Bioquimica Clinica, Facultad de Ciencias Quimicas, Universidad Nacional de Cordoba, Haya de la Torre y Medina Allende, Ciudad Universitaria, Cordoba X5000HUA, Argentina.
authors.forename: Javier A
authors.initials: JA
authors.lastname: Soria
authors.forename: Daniela S
authors.initials: DS
authors.lastname: Arroyo
authors.forename: Emilia A
authors.initials: EA
authors.lastname: Gaviglio
authors.forename: Maria C
authors.initials: MC
authors.lastname: Rodriguez-Galan
authors.forename: Ji Ming
authors.initials: JM
authors.lastname: Wang
authors.forename: Pablo
authors.initials: P
authors.lastname: Iribarren
mesh_terms: D016229:Amyloid beta-Peptides / Q000633:toxicity; D000818:Animals; D017209:Apoptosis / Q000276:immunology*; D053148:Caspase 3 / Q000502:physiology*; D061945:Caspase Inhibitors; D002470:Cell Survival / Q000276:immunology; D002478:Cells, Cultured; D018836:Inflammation Mediators / Q000037:antagonists & inhibitors / Q000502:physiology; D015847:Interleukin-4 / Q000502:physiology*; D051379:Mice; D008810:Mice, Inbred C57BL; D017628:Microglia / Q000201:enzymology / Q000276:immunology* / Q000473:pathology; D010446:Peptide Fragments / Q000633:toxicity; D000071137:Poly (ADP-Ribose) Polymerase-1; D011065:Poly(ADP-ribose) Polymerases / Q000096:biosynthesis / Q000378:metabolism; D019311:Staurosporine / Q000494:pharmacology
chemical_list: D016229:Amyloid beta-Peptides; D061945:Caspase Inhibitors; D018836:Inflammation Mediators; D010446:Peptide Fragments; C075222:amyloid beta-protein (1-42); D015847:Interleukin-4; C499321:Parp1 protein, mouse; D000071137:Poly (ADP-Ribose) Polymerase-1; D011065:Poly(ADP-ribose) Polymerases; C505409:Casp3 protein, mouse; D053148:Caspase 3; D019311:Staurosporine