Premium
P2‐058: A GLYCOMICS APPROACH FOR ANALYZING CEREBROSPINAL FLUID
Author(s) -
Gaunitz Stefan,
SchedinWeiss Sophia,
Winblad Bengt,
Tjernberg Lars
Publication year - 2014
Publication title -
alzheimer's and dementia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.713
H-Index - 118
eISSN - 1552-5279
pISSN - 1552-5260
DOI - 10.1016/j.jalz.2014.05.732
Subject(s) - glycomics , glycan , chemistry , chromatography , glycosylation , derivatization , membrane , pngase f , biochemistry , mass spectrometry , glycoprotein
Background: AD is characterized by deleterious deposits of Ab and t proteins, which are central to AD pathogenesis. In addition to these pathophysiological changes, AD is also characterized by abnormal glucose metabolism that precedes neuropathological changes. Despite these data, the underlying molecular mechanism behind the potential cause and effect relationship between decreased glucosemetabolism and increased Ab deposition is unknown. In this context, we hypothesized that decreased glucose metabolism may result in decreased Ab clearance and hence its increased deposition in AD brain. Here, it is noteworthy that Liver X receptor (LXR)-mediated Apolipoprotein E (APOE) lipidation and secretion plays a major role in cerebral Ab clearance. Therefore, we aimed to investigate glycolytic control of LXR-APOE pathway and identify its positive modulators for therapeutic purpose. Methods: The astrocytes expressing human APOE2/E3/E4 isoforms (from Dr. David Holtzman, Washington University) were used. The astrocytes were treated for 24 hrs with known LXR and RXR agonists (GW3965 and Bexarotene, respectively), either in presence or absence of inhibitors of glucose uptake and glycolysis (cytochalasin B and 2-deoxy-D-glucose, respectively). Furthermore, astrocytes were also treated with various FDA-approved drugs with potential to enhance glycolysis and in turn activating the LXR-APOE pathway. The uptake of glucose and the production of lactate were measured as markers of glycolysis. The level of secreted APOE was measured using human APOE ELISA, while lipidation status of APOE was measured using non-denaturing gel electrophoresis followed bywestern blotting.Results:The treatment of APOE3 astrocytes with Bexarotene increased APOE lipidation and secretion, which was inhibited by co-treatment with Cytochalasin B and 2-deoxy-D-glucose (Fig.1A). Furthermore, astrocytes were also treated with three drugs from three different categories viz., a b-blocker (Drug 1, 5mM), an anti-cancer agent (Drug 2, 5mM) and an anti-inflammatory agent (Drug 3, 2mM). The Drug 1 and 2 significantly enhanced glucose uptake and lactate production by astrocytes (Fig.1B). Interestingly, these two drugs also significantly enhanced APOE secretion (Fig.1B). The experiments with other drug molecules in APOE3 as well as APOE2 and E4 astrocytes are ongoing. Conclusions: Our data so far suggests potential role of glucose metabolism in APOE lipidation and secretion by astrocytes, further emphasizing our hypothesis.