Ceramides (CER) are involved in alcohol induced neuroinflammation. In a mouse model of chronic alcohol exposure, 16 CER and 18 sphingomyelin (SM) concentrations from whole brain lipid extracts were measured using ESI mass spectrometry. All 18 CER concentrations in alcohol exposed adults increased significantly; in juveniles, 6 CER decreased. In contrast, only three SM decreased in adult and one increased significantly in juvenile. Next, regional identification at 50 m spatial resolution from coronal sections was obtained with matrix assisted laser desorption/ionization mass spectrometry imaging (MALDI-MSI) by implanting silver nanoparticulate matrices followed by focused laser desorption. Most of the CER and SM quantified in whole brain extracts were detected in MALDI images. Coronal sections from three brain levels show qualitative regional changes in CER-SM ion intensities, as a function of group and brain region, in cortex, striatum, accumbens, habenula, and hippocampus. Highly correlated changes in certain white matter CER-SM pairs occur in regions across all groups, including the hippocampus and the lateral (but not medial) cerebellar cortex of adult mice. A more comprehensive lipidomic study was conducted on whole brain lipid extracts. In this study, we analyzed lipid composition of chronically ethanol exposed mouse brains from juveniles (JUV) and adults (ADU). Total lipid extractions for brains were fractionated into lipid classes by solid phase extraction. Each fraction was analyzed by electrospray ionization mass spectrometry (ESI-MS). A total of 380 lipids from 16 lipid classes were identified. The results were processed by multivariate analysis to highlight lipid class differences between control and alcohol consumption groups. The first important observation is that alcohol seems to have opposite markedly different effect on lipid content in juvenile brain compared with adult brain. Additionally, significant changes were observed in different lipid classes including sphingolipids, fatty acids, lysophosphatidylcholines, and other glycerophospholipids. Free fatty acids and lysophosphatidylcholines are both generated by phospholipase A2. Neuroinflammation and brain damage caused by chronic alcohol consumption or other neurodegenerative diseases have implicated phospholipase A2,including demyelination.
| Roux, Aurelie; Muller, Ludovic; Jackson, Shelley N et al. (2015) Chronic ethanol consumption profoundly alters regional brain ceramide and sphingomyelin content in rodents. ACS Chem Neurosci 6:247-59 |
