title: Tandem Mass Spectrometry Multiplex Analysis of Glucosylceramide and Galactosylceramide Isoforms in Brain Tissues at Different Stages of Parkinson Disease.
abstract: Previous studies demonstrated that Parkinson disease (PD) is associated with a decreased activity of the glucocerebrosidase (GCase) enzyme in brain tissues. The objective of this study was to determine if GCase deficiency is associated with the accumulation of its glucosylceramide (GluCer) substrate in PD brain tissues. An ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method was developed, optimized, and validated for the multiplex analysis of GluCer isoforms (C18:0, C20:0, C22:0, C24:1, and C24:0) in brain tissue samples. These molecules were chromatographically separated from their isobaric galactosylceramide (GalCer) counterparts using normal phase chromatography. The analysis was performed by tandem mass spectrometry in the multiple reaction monitoring (MRM) acquisition mode. Limits of detection ranging from 0.4 to 1.1 nmol/g brain tissue were established for the different GluCer isoforms analyzed. For the first time, GluCer isoform levels were analyzed in temporal cortex brain tissue samples from 26 PD patients who were divided into three PD disease stages (IIa, III, and IV) according to the Unified Staging System for Lewy Body Disorders. These specimens were compared with brain tissue samples from 12 controls and 6 patients with Incidental Lewy Body Disease. No significant GluCer concentration differences were observed between the 5 sample groups. The GluCer isoform levels were also normalized with their matching GalCer isoforms. The normalized results showed a trend for GluCer levels which increased with PD severity. However, the differences observed between the groups were not significant, owing likely to the high standard deviations measured.
authors.affiliation: Division of Medical Genetics, Department of Pediatrics, Centre de Recherche-CHUS, Faculty of Medicine and Health Sciences, Université de Sherbrooke , 3001, 12th Avenue North, Sherbrooke, Quebec, Canada , J1H 5N4.
authors.forename: Michel
authors.initials: M
authors.lastname: Boutin
authors.affiliation: Division of Human Genetics, Cincinnati Children's Hospital Medical Center , R Building Room1401, 3333 Burnet Avenue, Cincinnati, Ohio 45229, United States.
authors.forename: Ying
authors.initials: Y
authors.lastname: Sun
authors.affiliation: Department of Pathology, Molecular and Cellular Pathology Division, University of Alabama at Birmingham , 1670 University Boulevard, VH G019H, Birmingham, Alabama 35294, United States.|Birmingham VA Medical Center , Birmingham, Alabama 35233, United States.
authors.forename: John J
authors.initials: JJ
authors.lastname: Shacka
authors.affiliation: Division of Medical Genetics, Department of Pediatrics, Centre de Recherche-CHUS, Faculty of Medicine and Health Sciences, Université de Sherbrooke , 3001, 12th Avenue North, Sherbrooke, Quebec, Canada , J1H 5N4.
authors.forename: Christiane
authors.initials: C
authors.lastname: Auray-Blais
mesh_terms: D000818:Animals; D001921:Brain / Q000378:metabolism*; D002851:Chromatography, High Pressure Liquid; D004195:Disease Models, Animal; D005699:Galactosylceramides / Q000032:analysis* / Q000737:chemistry; D005963:Glucosylceramides / Q000032:analysis* / Q000737:chemistry; D006801:Humans; D051379:Mice; D018345:Mice, Knockout; D015394:Molecular Structure; D010300:Parkinson Disease / Q000175:diagnosis / Q000378:metabolism*; D053719:Tandem Mass Spectrometry
chemical_list: D005699:Galactosylceramides; D005963:Glucosylceramides