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Published byEmma Jefferson Modified over 9 years ago
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Elevated Levels of Cholesterol Metabolites in NPC Phenotype Cells Daniel Witter Scripps/ Oxford Lab Glycobiology Institute Oxford University
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Niemann-Pick C Disease GSL storage disease Cholesterol accumulation Intracellular mistrafficking Neurodegeneration Upregulated microglia and astrocyte activity
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Cholesterol oxidation
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Reactive Oxygen Species >Superoxide O 2 - >Hydrogen Peroxide H 2 O 2 >Hydroxyl radical OH >Singlet Molecular Oxygen 1 O 2 >Ozone? O 3
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Atheronals 5-6 secosterol oxidation products Steroid nucleus is cleaved Ketoaldehyde 1 Aldol 2 Produced by singlet molecular oxygen and possibly ozone
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Where are atheronals? Found in serum Found in atherosclerotic plaques Found in brain tissue Need cholesterol and inflammation together
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Biological significance of atheronals Macrophage recruitment Upregulation of SR-A Monocyte differentiation ß-amyloid misfolding
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Cholesterol accumulation in NPC disease Wild type NPC1 null Filipin labeled B-lymphoblasts bar=5µm
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Finding Atheronals in NPC Cells ROS generation--light activated hematoporphyrin IX Lipid extraction Derivatization with 2,4-DNPH HPLC
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mAU minutes Aldol Isocratic gradient--85% acetonitrile; 12%water w/ 0.1%TFA; 3%methanol Untreated NPC cells
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HPLC Wild type NPC mAU minutes aldol Isocratic gradient--85% acetonitrile; 12%water w/ 0.1%TFA; 3%methanol
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Microscopy Fluorescent dansyl amide derivatized atheronal
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ATHERONAL LOCALIZATION RAW macrophages treated with 50 µM DA aldol for 60 minutes, followed by 15 minute paraformaldehyde fix, 60 minute block, and 60 minute stain with FITC anti-GM130.
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ATHERONAL LOCALIZATION RAW macrophages treated with 50 µM DA aldol for 60 minutes, followed by 15 minute paraformaldehyde fix, 60 minute block, and 60 minute stain with FITC anti-calnexin.
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ATHERONAL LOCALIZATION RAW macrophages treated with 50 µM DA aldol for 60 minutes, followed by 15 minute paraformaldehyde fix, 60 minute block, and 10 minute stain with DiI.
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ATHERONAL LOCALIZATION Live RAW macrophage treated with 50 µM DA aldol for 1 hr. LiveRAW macrophage treated with 50 µM DA aldol for 2 hr.
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Conclusions Atheronal levels are higher in NPC cells ROS raise atheronal levels Atheronals appear to localize in the ER
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Future Work IF microscopy Lipid raft isolation Glutathione depletion Other cell lines
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Acknowledgements Paul Wentworth/ Raymond Dwek John Offer Jorge Nieva Emyr Lloyd-Evans GBI State of Florida
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