出版社：American Society for Biochemistry and Molecular Biology
摘要：Globoid cell leukodystrophy (Krabbe disease) is an inheritedneurological disorder caused by the pathogenomic accumulationof psychosine (galactosylsphingosine), a substrate for the deficientenzyme galactocerebroside ß-galactosidase. This studyunderscores the mechanism of action of psychosine in the regulationof oligodendrocyte cell death via the generation of lysophosphatidylcholine(LPC) and arachidonic acid (AA) by the activation of secretoryphospholipase A2 (sPLA2). There was a significant increase inthe level of LPC, indicating a phospholipase A2 (PLA2)-dependentpathobiology, in the brains of Krabbe disease patients and thoseof twitcher mice, an animal model of Krabbe disease. In vitrostudies of the treatment of primary oligodendrocytes and theoligodendrocyte MO3.13 cell line with psychosine also showedthe generation of LPC and the release of AA in a dose- and time-dependentmanner, indicating psychosine-induced activation of PLA2. Studieswith various pharmacological inhibitors of cytosolic phospholipaseA2 and sPLA2 and psychosine-mediated induction of sPLA2 enzymaticactivity in media supernatant suggest that psychosine-inducedrelease of AA and generation of LPC is mainly contributed bysPLA2. An inhibitor of sPLA2, 7,7-dimethyl eicosadienoic acid,completely attenuated the psychosine-mediated accumulation ofLPC levels, release of AA, and generation of reactive oxygenspecies, and blocked oligodendroyte cell death, as evident fromcell survival, DNA fragmentation, and caspase 3 activity assays.This study documents for the first time that psychosine-inducedcell death is mediated via the sPLA2 signaling pathway and thatinhibitors of sPLA2 may hold a therapeutic potential for protectionagainst oligodendrocyte cell death and resulting demyelinationin Krabbe disease.Supplementary key words twitcher • apopoptosis • sPLA2 inhibitor • LPC
Abbreviations: AA, arachidonic acid; CAT, chloramphenicol acetyltransferase; CNS, central nervous system; cPLA2, cytosolic phospholipase A2; DCFDA, 6-carboxy 2', 7'-dichlorodihydrofluorescein diacetate; DEDA, 7,7-dimethyl eicosadienoic acid; iPLA2, calcium-independent phospholipase A2; LPC, lysophosphatidylcholine; NAC, N-acetylcysteine; PLA2, phospholipase A2; ROS, reactive oxygen species; sPLA2, secretory phospholipase A2; TNF, tumor necrosis factor-
, tumor necrosis factor-
