Macarena Hernández-Jiménez1, Diego Martínez-López2, Enrique Gabandé-Rodríguez2, Adrian Martín-Segura2, Ignacio Lizasoain2, María D Ledesma2, Carlos G Dotti2, María A Moro1. 1. From the Unidad de Investigación Neurovascular, Departamento de Farmacología, Facultad de Medicina, Universidad Complutense and Instituto de Investigación Hospital 12 de Octubre (i+12), Madrid, Spain (M.H.-J., D.M.-L., I.L., M.A.M.); and Centro de Biología Molecular Severo Ochoa, CSIC, Madrid, Spain (E.G.-R., A.M.-S., M.D.L., C.G.D.). neurona@ucm.es. 2. From the Unidad de Investigación Neurovascular, Departamento de Farmacología, Facultad de Medicina, Universidad Complutense and Instituto de Investigación Hospital 12 de Octubre (i+12), Madrid, Spain (M.H.-J., D.M.-L., I.L., M.A.M.); and Centro de Biología Molecular Severo Ochoa, CSIC, Madrid, Spain (E.G.-R., A.M.-S., M.D.L., C.G.D.).
Abstract
BACKGROUND AND PURPOSE: 3β-Hydroxysteroid-Δ24 reductase (DHCR24) or selective alzheimer disease indicator 1 (seladin-1), an enzyme of cholesterol biosynthetic pathway, has been implicated in neuroprotection, oxidative stress, and inflammation. However, its role in ischemic stroke remains unexplored. The aim of this study was to characterize the effect of seladin-1/DHCR24 using an experimental stroke model in mice. METHODS: Dhcr24(+/-) and wild-type (WT) mice were subjected to permanent middle cerebral artery occlusion. In another set of experiments, WT mice were treated intraperitoneally either with vehicle or U18666A (seladin-1/DHCR24 inhibitor, 10 mg/kg) 30 minutes after middle cerebral artery occlusion. Brains were removed 48 h after middle cerebral artery occlusion for infarct volume determination. For protein expression determination, peri-infarct region was obtained 24 h after ischemia, and Western blot or cytometric bead array was performed. RESULTS: Dhcr24(+/-) mice displayed larger infarct volumes after middle cerebral artery occlusion than their WT littermates. Treatment of WT mice with the seladin-1/DHCR24 inhibitor U18666A also increased ischemic lesion. Inflammation-related mediators were increased after ischemia in Dhcr24(+/-) mice compared with WT counterparts. Consistent with a role of cholesterol in proper function of glutamate transporter EAAT2 in membrane lipid rafts, we found a decreased association of EAAT2 with lipid rafts after ischemia when DHCR24 is genetically deleted or pharmacologically inhibited. Accordingly, treatment with U18666A decreases [(3)H]-glutamate uptake in cultured astrocytes. CONCLUSIONS: These results support the idea that lipid raft integrity, ensured by seladin-1/DHCR24, plays a crucial protective role in the ischemic brain by guaranteeing EAAT2-mediated uptake of glutamate excess.
BACKGROUND AND PURPOSE: 3β-Hydroxysteroid-Δ24 reductase (DHCR24) or selective alzheimer disease indicator 1 (seladin-1), an enzyme of cholesterol biosynthetic pathway, has been implicated in neuroprotection, oxidative stress, and inflammation. However, its role in ischemic stroke remains unexplored. The aim of this study was to characterize the effect of seladin-1/DHCR24 using an experimental stroke model in mice. METHODS:Dhcr24(+/-) and wild-type (WT) mice were subjected to permanent middle cerebral artery occlusion. In another set of experiments, WT mice were treated intraperitoneally either with vehicle or U18666A (seladin-1/DHCR24 inhibitor, 10 mg/kg) 30 minutes after middle cerebral artery occlusion. Brains were removed 48 h after middle cerebral artery occlusion for infarct volume determination. For protein expression determination, peri-infarct region was obtained 24 h after ischemia, and Western blot or cytometric bead array was performed. RESULTS:Dhcr24(+/-) mice displayed larger infarct volumes after middle cerebral artery occlusion than their WT littermates. Treatment of WT mice with the seladin-1/DHCR24 inhibitor U18666A also increased ischemic lesion. Inflammation-related mediators were increased after ischemia in Dhcr24(+/-) mice compared with WT counterparts. Consistent with a role of cholesterol in proper function of glutamate transporter EAAT2 in membrane lipid rafts, we found a decreased association of EAAT2 with lipid rafts after ischemia when DHCR24 is genetically deleted or pharmacologically inhibited. Accordingly, treatment with U18666A decreases [(3)H]-glutamate uptake in cultured astrocytes. CONCLUSIONS: These results support the idea that lipid raft integrity, ensured by seladin-1/DHCR24, plays a crucial protective role in the ischemic brain by guaranteeing EAAT2-mediated uptake of glutamate excess.
Authors: Henna Martiskainen; Kaisa M A Paldanius; Teemu Natunen; Mari Takalo; Mikael Marttinen; Stina Leskelä; Nadine Huber; Petra Mäkinen; Enni Bertling; Hiramani Dhungana; Mikko Huuskonen; Paavo Honkakoski; Pirta Hotulainen; Kirsi Rilla; Jari Koistinaho; Hilkka Soininen; Tarja Malm; Annakaisa Haapasalo; Mikko Hiltunen Journal: J Neuroinflammation Date: 2017-11-07 Impact factor: 8.322