Insulin Rescued MCP-1-Suppressed Cholesterol Efflux to Large HDL2 Particles via ABCA1, ABCG1, SR-BI and PI3K/Akt Activation in Adipocytes

Runlu Sun, Pu Fang, Jieyu Jiang, Canxia Huang, Junjie Wang, Qi Guo, Hongwei Li, Xiaoying Wu, Xiangkun Xie, Yuan Jiang, Qian Chen, Jinlan Bao, Jingfeng Wang, Hong Wang, Yuling Zhang

Research output: Contribution to journalArticlepeer-review

5 Scopus citations

Abstract

PURPOSE: Intracellular cholesterol imbalance plays an important role in adipocyte dysfunction of obesity. However, it is unclear whether obesity induced monocyte chemoattractant protein-1 (MCP-1) causes the adipocyte cholesterol imbalance. In this study, we hypothesize that MCP-1 impairs cholesterol efflux of adipocytes to HDL2 and insulin rescues this process.

METHODS: We recruited coronary artery disease (CAD) patients with obesity and overweight to analyze the association between MCP-1 and HDL2-C by Pearson correlation coefficients. We performed [ 3H]-cholesterol efflux assay to demonstrate the effect of MCP-1 and insulin on cholesterol efflux from 3T3-L1 adipocytes to large HDL2 particles. Western blot, RT-qPCR, cell-surface protein assay, and confocal microscopy were performed to determine the regulatory mechanism.

RESULTS: Plasma MCP-1 concentrations were negatively correlated with HDL2-C in CAD patients with obesity and overweight (r = -0.60, p < 0.001). In differentiated 3T3-L1 adipocytes, MCP-1 reduced cholesterol efflux to large HDL2 particles by 55.4% via decreasing ATP-binding cassette A1 (ABCA1), ABCG1, and scavenger receptor class B type I (SR-BI) expression. Intriguingly, insulin rescued MCP-1 mediated-inhibition of cholesterol efflux to HDL2 in an Akt phosphorylation-dependent manner. The rescue efficacy of insulin was 138.2% for HDL2. Moreover, insulin increased mRNA and protein expression of ABCA1, ABCG1, and SR-BI at both transcriptional and translational levels via the PI3K/Akt activation.

CONCLUSIONS: These findings indicate that MCP-1 impairs cholesterol efflux to large HDL2 particles in adipocytes, which is reversed by insulin via the upregulation of ABCA1, ABCG1, and SR-BI. Therefore, insulin might improve cholesterol imbalance by an anti-inflammatory effect in adipocytes.

CLINICAL TRIAL REGISTRATION NUMBER: ChiCTR2000033297; Date of registration: 2020/05/ 27; Retrospectively registered.

Original languageEnglish
Pages (from-to)665-678
Number of pages14
JournalCardiovascular Drugs and Therapy
Volume36
Issue number4
DOIs
StatePublished - Aug 2022

Keywords

  • Adipocytes
  • Cholesterol efflux; large HDL2 particles
  • Insulin
  • MCP-1
  • Cholesterol/metabolism
  • Humans
  • Adipocytes/metabolism
  • Phosphatidylinositol 3-Kinases/metabolism
  • ATP Binding Cassette Transporter, Subfamily G, Member 1/genetics
  • Proto-Oncogene Proteins c-akt/metabolism
  • Scavenger Receptors, Class B/genetics
  • Overweight/metabolism
  • Cholesterol, HDL
  • Chemokine CCL2/metabolism
  • ATP-Binding Cassette Transporters/genetics
  • ATP Binding Cassette Transporter 1/genetics
  • Obesity/drug therapy

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