Perilipin 2 (PLIN2)-deficiency does not increase cholesterol-induced toxicity in macrophages

PLoS One. 2012;7(3):e33063. doi: 10.1371/journal.pone.0033063. Epub 2012 Mar 12.

Abstract

Interventions on macrophages/foam cells to redirect intracellular cholesterol towards efflux pathways could become a very valuable addition to our therapeutic arsenal against atherosclerosis. However, certain manipulations of the cholesteryl ester cycle, such as the inhibition of ACAT1, an ER-resident enzyme that re-esterifies cholesterol, are not well tolerated. Previously we showed that targeting perilipin-2 (PLIN2), a major lipid droplet (LD)-associated protein in macrophages, prevents foam cell formation and protects against atherosclerosis. Here we have assessed the tolerance of PLIN2-deficient bone marrow derived macrophages (BMM) to several lipid loading conditions similar to the found during atherosclerosis development, including exposure to modified low-density lipoprotein (mLDL) and 7-ketocholesterol (7-KC), a free cholesterol (FC) metabolite, in media with or without cholesterol acceptors. BMM isolated from mice that do or do not express PLIN2 were tested for apoptosis (TUNEL and cleaved caspase-3), ER stress (CHOP induction and XBP-1 splicing), and inflammation (TNF-α and IL-6 mRNA levels). Like in other cell types, PLIN2 deficiency impairs LD buildup in BMM. However, while most stress parameters were elevated in macrophages under ACAT inhibition and 7-KC loading, PLIN2 inactivation was well tolerated. The data support the safety of targeting PLIN2 to prevent foam cell formation and atherosclerosis.

Publication types

  • Comparative Study
  • Research Support, N.I.H., Extramural

MeSH terms

  • Analysis of Variance
  • Animals
  • Apoptosis / physiology
  • Atherosclerosis / metabolism*
  • Atherosclerosis / prevention & control
  • Azo Compounds
  • Blotting, Western
  • Cell Culture Techniques
  • Cholesterol, LDL / metabolism*
  • Cholesterol, LDL / toxicity
  • DNA Primers / genetics
  • Endoplasmic Reticulum Stress / physiology
  • Foam Cells / metabolism
  • In Situ Nick-End Labeling
  • Interleukin-6 / metabolism
  • Ketocholesterols / metabolism
  • Macrophages / metabolism*
  • Membrane Proteins / deficiency*
  • Mice
  • Mice, Inbred C57BL
  • Perilipin-2
  • Reverse Transcriptase Polymerase Chain Reaction
  • Tumor Necrosis Factor-alpha / metabolism

Substances

  • Azo Compounds
  • Cholesterol, LDL
  • DNA Primers
  • Interleukin-6
  • Ketocholesterols
  • Membrane Proteins
  • Perilipin-2
  • Plin2 protein, mouse
  • Tumor Necrosis Factor-alpha
  • oil red O
  • 7-ketocholesterol