title: Novel aspirin-triggered neuroprotectin D1 attenuates cerebral ischemic injury after experimental stroke.
abstract: Acute ischemic stroke triggers complex neurovascular, neuroinflammatory and synaptic alterations. Aspirin and docosahexaenoic acid (DHA), an omega-3 essential fatty acid family member, have beneficial effects on cerebrovascular diseases. DHA is the precursor of neuroprotectin D1 (NPD1), which downregulates apoptosis and, in turn, promotes cell survival. Here we have tested the effect of aspirin plus DHA administration and discovered the synthesis of aspirin-triggered NPD1 (AT-NPD1) in the brain. Then we performed the total chemical synthesis of this molecule and tested in the setting of 2h middle cerebral artery occlusion (MCAo) in Sprague-Dawley rats. Neurological status was evaluated at 24h, 48 h, 72 h, and 7 days. At 3h post-stroke onset, an intravenous administration of 333 μg/kg of AT-NPD1 sodium salt (AT-NPD1-SS) or methyl-ester (AT-NPD1-ME) or vehicle (saline) as treatment was given. On day 7, ex vivo magnetic resonance imaging (MRI) of the brains was conducted on 11.7 T MRI. T2WI, 3D volumes, and apparent diffusion coefficient (ADC) maps were generated. In addition, infarct volumes and number of GFAP (reactive astrocytes), ED-1 (activated microglia/macrophages) and SMI-71-positive vessels were counted in the cortex and striatum at the level of the central lesion. All animals showed similar values for rectal and cranial temperatures, arterial blood gases, and plasma glucose during and after MCAo. Treatment with both AT-NPD1-SS and AT-NPD1-ME significantly improved neurological scores compared to saline treatment at 24h, 48 h, 72 h and 7 days. Total lesion volumes computed from T2WI images were significantly reduced by both AT-NPD1-SS and AT-NPD1-ME treatment in the cortex (by 44% and 81%), striatum (by 61% and 77%) and total infarct (by 48% and 78%, respectively). Brain edema, computed from T2WI in the cortex (penumbra) and striatum (core), was elevated in the saline group. In contrast, both AT-NPD1 decreased water content in the striatum on day 7. 3D volumes, computed from T2WI, were dramatically reduced with both AT-NPD1 and the lesion was mostly localized in the subcortical areas. Treatment with both AT-NPD1-SS and AT-NPD1-ME significantly reduced cortical (by 76% and 96%), subcortical (by 61% and 70%) and total (69% and 84%, respectively) infarct volumes as defined by histopathology. In conclusion, a novel biosynthetic pathway that leads to the formation of AT-NPD1 mediator in the brain was discovered. In addition, administration of synthetic AT-NPD1, in either its sodium salt or as the methyl ester, was able to attenuate cerebral ischemic injury which leads to a novel approach for pharmaceutical intervention and clinical translation.
authors.affiliation: Neuroscience Center of Excellence, School of Medicine, Louisiana State University Health Sciences Center, New Orleans, LA 70112, USA. nbazan@lsuhsc.edu
authors.forename: Nicolas G
authors.initials: NG
authors.lastname: Bazan
authors.forename: Tiffany N
authors.initials: TN
authors.lastname: Eady
authors.forename: Larissa
authors.initials: L
authors.lastname: Khoutorova
authors.forename: Kristal D
authors.initials: KD
authors.lastname: Atkins
authors.forename: Song
authors.initials: S
authors.lastname: Hong
authors.forename: Yan
authors.initials: Y
authors.lastname: Lu
authors.forename: Changde
authors.initials: C
authors.lastname: Zhang
authors.forename: Bokkyoo
authors.initials: B
authors.lastname: Jun
authors.forename: Andre
authors.initials: A
authors.lastname: Obenaus
authors.forename: Gabrielle
authors.initials: G
authors.lastname: Fredman
authors.forename: Min
authors.initials: M
authors.lastname: Zhu
authors.forename: Jeremy W
authors.initials: JW
authors.lastname: Winkler
authors.forename: Nicos A
authors.initials: NA
authors.lastname: Petasis
authors.forename: Charles N
authors.initials: CN
authors.lastname: Serhan
authors.forename: Ludmila
authors.initials: L
authors.lastname: Belayev
mesh_terms: D000818:Animals; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000494:pharmacology*; D001241:Aspirin / Q000494:pharmacology*; D002545:Brain Ischemia / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology; D004281:Docosahexaenoic Acids / Q000096:biosynthesis / Q000502:physiology*; D020244:Infarction, Middle Cerebral Artery / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D000894:Anti-Inflammatory Agents, Non-Steroidal; C487679:protectin D1; D004281:Docosahexaenoic Acids; D001241:Aspirin