title: iPLA2β knockout mouse, a genetic model for progressive human motor disorders, develops age-related neuropathology.
abstract: Calcium-independent phospholipase A2 group VIa (iPLA2β) preferentially releases docosahexaenoic acid (DHA) from the sn-2 position of phospholipids. Mutations of its gene, PLA2G6, are found in patients with several progressive motor disorders, including Parkinson disease. At 4 months, PLA2G6 knockout mice (iPLA2β(-/-)) show minimal neuropathology but altered brain DHA metabolism. By 1 year, they develop motor disturbances, cerebellar neuronal loss, and striatal α-synuclein accumulation. We hypothesized that older iPLA2β(-/-) mice also would exhibit inflammatory and other neuropathological changes. Real-time polymerase chain reaction and Western blotting were performed on whole brain homogenate from 15 to 20-month old male iPLA2β(-/-) or wild-type (WT) mice. These older iPLA2β(-/-) mice compared with WT showed molecular evidence of microglial (CD-11b, iNOS) and astrocytic (glial fibrillary acidic protein) activation, disturbed expression of enzymes involved in arachidonic acid metabolism, loss of neuroprotective brain derived neurotrophic factor, and accumulation of cytokine TNF-α messenger ribonucleic acid, consistent with neuroinflammatory pathology. There was no evidence of synaptic loss, of reduced expression of dopamine active reuptake transporter, or of accumulation of the Parkinson disease markers Parkin or Pink1. iPLA2γ expression was unchanged. iPLA2β deficient mice show evidence of neuroinflammation and associated neuropathology with motor dysfunction in later life. These pathological biomarkers could be used to assess efficacy of dietary intervention, antioxidants or other therapies on disease progression in this mouse model of progressive human motor diseases associated with a PLA2G6 mutation.
authors.affiliation: Brain Physiology and Metabolism Section, Laboratory of Neurosciences, National Institute on Aging, National Institutes of Health, Bldg. 9, Room 1S126, 9000 Rockville Pike, Bethesda, MD, 20892, USA, helene.blanchard@nih.gov.
authors.forename: Helene
authors.initials: H
authors.lastname: Blanchard
authors.forename: Ameer Y
authors.initials: AY
authors.lastname: Taha
authors.forename: Yewon
authors.initials: Y
authors.lastname: Cheon
authors.forename: Hyung-Wook
authors.initials: HW
authors.lastname: Kim
authors.forename: John
authors.initials: J
authors.lastname: Turk
authors.forename: Stanley I
authors.initials: SI
authors.lastname: Rapoport
mesh_terms: D000375:Aging / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D004195:Disease Models, Animal; D018450:Disease Progression; D054522:Group VI Phospholipases A2 / Q000172:deficiency* / Q000235:genetics; D008297:Male; D051379:Mice; D018345:Mice, Knockout; D019957:Motor Skills Disorders / Q000235:genetics / Q000378:metabolism* / Q000473:pathology
chemical_list: D054522:Group VI Phospholipases A2; C516476:Pla2g6 protein, mouse