Protein kinase R-like endoplasmic reticulum kinase and glycogen synthase kinase-3α/ß regulate foam cell formation.
J Lipid Res
; 55(11): 2320-33, 2014 Nov.
Article
in En
| MEDLINE
| ID: mdl-25183803
ABSTRACT
Evidence suggests a causative role for endoplasmic reticulum (ER) stress in the development of atherosclerosis. This study investigated the potential role of glycogen synthase kinase (GSK)-3α/ß in proatherogenic ER stress signaling. Thp1-derived macrophages were treated with the ER stress-inducing agents, glucosamine, thapsigargin, or palmitate. Using small-molecule inhibitors of specific unfolded protein response (UPR) signaling pathways, we found that protein kinase R-like ER kinase (PERK), but not inositol requiring enzyme 1 or activating transcription factor 6, is required for the activation of GSK3α/ß by ER stress. GSK3α/ß inhibition or siRNA-directed knockdown attenuated ER stress-induced expression of distal components of the PERK pathway. Macrophage foam cells within atherosclerotic plaques and isolated macrophages from ApoE(-/-) mice fed a diet supplemented with the GSK3α/ß inhibitor valproate had reduced levels of C/EBP homologous protein (CHOP). GSK3α/ß inhibition blocked ER stress-induced lipid accumulation and the upregulation of genes associated with lipid metabolism. In primary mouse macrophages, PERK inhibition blocked ER stress-induced lipid accumulation, whereas constitutively active S9A-GSK3ß promoted foam cell formation and CHOP expression, even in cells treated with a PERK inhibitor. These findings suggest that ER stress-PERK-GSK3α/ß signaling promotes proatherogenic macrophage lipid accumulation.
Key words
Full text:
1
Database:
MEDLINE
Main subject:
EIF-2 Kinase
/
Glycogen Synthase Kinase 3
/
Foam Cells
Limits:
Animals
/
Female
/
Humans
Language:
En
Journal:
J Lipid Res
Year:
2014
Type:
Article
Affiliation country:
Canada