title: Selenoprotein K is required for palmitoylation of CD36 in macrophages: implications in foam cell formation and atherogenesis.
abstract: Selk is an ER transmembrane protein important for calcium flux and macrophage activation, but its role in foam cell formation and atherosclerosis has not been evaluated. BMDMs from Selk(-/-) mice exhibited decreased uptake of modLDL and foam cell formation compared with WT controls, and the differences were eliminated with anti-CD36 blocking antibody. CD36 expression was decreased in TNF-α-stimulated Selk(-/-) BMDMs compared with WT controls. Fluorescence microscopy revealed TNF-α-induced clustering of CD36 in WT BMDMs indicative of lipid raft localization, which was absent in Selk(-/-) BMDMs. Fractionation revealed lower levels of CD36 reaching lipid rafts in TNF-α-stimulated Selk(-/-) BMDMs. Immunoprecipitation showed that Selk(-/-) BMDMs have decreased CD36 palmitoylation, which occurs at the ER membrane and is crucial for stabilizing CD36 expression and directing its localization to lipid rafts. To assess if this phenomenon had a role in atherogenesis, a HFD was fed to irradiated Ldlr(-/-) mice reconstituted with BM from Selk(-/-) or WT mice. Selk was detected in aortic plaques of controls, particularly in macrophages. Selk(-/-) in immune cells led to reduction in atherosclerotic lesion formation without affecting leukocyte migration into the arterial wall. These findings suggest that Selk is important for stable, localized expression of CD36 in macrophages during inflammation, thereby contributing to foam cell formation and atherogenesis.
authors: Center for Cardiovascular Research, John A. Burns School of Medicine, University of Hawaii, Honolulu, Hawaii 96813, USA.
authors: Svenja
authors: S
authors: Meiler
authors: Yvonne
authors: Y
authors: Baumer
authors: Zhi
authors: Z
authors: Huang
authors: Fukun W
authors: FW
authors: Hoffmann
authors: Gregory J
authors: GJ
authors: Fredericks
authors: Aaron H
authors: AH
authors: Rose
authors: Robert L
authors: RL
authors: Norton
authors: Peter R
authors: PR
authors: Hoffmann
authors: William A
authors: WA
authors: Boisvert
mesh_terms: D000818:Animals; D050197:Atherosclerosis / Q000209:etiology*; D018955:CD36 Antigens / Q000378:metabolism*; D002478:Cells, Cultured; D005487:Foam Cells / Q000502:physiology*; D008077:Lipoproteins, LDL / Q000378:metabolism; D054878:Lipoylation; D008264:Macrophages / Q000378:metabolism*; D051379:Mice; D008810:Mice, Inbred C57BL; D051140:Selenoproteins / Q000502:physiology*; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology
chemical_list: D018955:CD36 Antigens; D008077:Lipoproteins, LDL; D051140:Selenoproteins; D014409:Tumor Necrosis Factor-alpha