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SCAP deficiency facilitates obesity and insulin resistance through shifting adipose tissue macrophage polarization

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Author(s)
Jae-Ho LeeSun Hee LeeEun-Ho LeeJeong-Yong ChoDae-Kyu SongYoung Jae LeeTaeg Kyu KwonByung-Chul OhKae Won ChoTimothy F. OsborneTae-Il JeonSeung-Soon Im
Keimyung Author(s)
Song, Dae KyuKwon, Taeg KyuIm, Seung Soon
Department
Dept. of Physiology (생리학)
Dept. of Immunology (면역학)
Journal Title
J Adv Res
Issued Date
2023
Volume
45
Keyword
SCAPWhite adipose tissueMacrophagesCholesterol 25-hydroxylaseCholesterol efflux
Abstract
Introduction:
Sterol regulatory element binding protein (SREBP) cleavage-associating protein (SCAP) is a sterol-regulated escort protein that translocates SREBPs from the endoplasmic reticulum to the Golgi apparatus, thereby activating lipid metabolism and cholesterol synthesis. Although SCAP regulates lipid metabolism in metabolic tissues, such as the liver and muscle, the effect of macrophage-specific SCAP deficiency in adipose tissue macrophages (ATMs) of patients with metabolic diseases is not completely understood.

Objectives:
Here, we examined the function of SCAP in high-fat/high-sucrose diet (HFHS)-fed mice and investigated its role in the polarization of classical activated macrophages in adipose tissue.

Methods:
Macrophage-specific SCAP knockout (mKO) mice were generated through crossbreeding lysozyme 2-cre mice with SCAP floxed mice which were then fed HFHS for 12 weeks. Primary macrophages were derived from bone marrow cells and analyzed further.

Results:
We found that fat accumulation and the appearance of proinflammatory M1 macrophages were both higher in HFHS-fed SCAP mKO mice relative to floxed control mice. We traced the effect to a defect in the lipopolysaccharide-mediated increase in SREBP-1a that occurs in control but not SCAP mKO mice. Mechanistically, SREBP-1a increased expression of cholesterol 25-hydroxylase transcription, resulting in an increase in the production of 25-hydroxycholesterol (25-HC), an endogenous agonist of liver X receptor alpha (LXRα) which increased expression of cholesterol efflux to limit cholesterol accumulation and M1 polarization. In the absence of SCAP mediated activation of SREBP-1a, increased M1 macrophage polarization resulted in reduced cholesterol efflux downstream from 25-HC-dependent LXRα activation.

Conclusion:
Overall, the activation of the SCAP-SREBP-1a pathway in macrophages may provide a novel therapeutic strategy that ameliorates obesity by controlling cholesterol homeostasis in ATMs.
Keimyung Author(s)(Kor)
송대규
권택규
임승순
Publisher
School of Medicine (의과대학)
Type
Article
ISSN
2090-1232
Source
https://www.sciencedirect.com/science/article/pii/S2090123222001242
DOI
10.1016/j.jare.2022.05.013
URI
https://kumel.medlib.dsmc.or.kr/handle/2015.oak/44704
Appears in Collections:
1. School of Medicine (의과대학) > Dept. of Immunology (면역학)
1. School of Medicine (의과대학) > Dept. of Physiology (생리학)
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