HDL does not influence the polarization of human monocytes toward an alternative phenotype

Sophie Colin, Melanie Fanchon, Loic Belloy, Andrea E. Bochem, Corinne Copin, Bruno Derudas, Erik S. G. Stroes, G. Kees Hovingh, Jan A. Kuivenhoven, Geesje M. Dallinga-Thie*, Bart Staels, Giulia Chinetti-Gbaguidi

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

16 Citations (Scopus)

Abstract

BACKGROUND: Macrophages are crucial cells in the pathogenesis of atherosclerosis. Macrophages are plastic cells which can switch from a classical pro-inflammatory M1 to an alternative anti-inflammatory M2 macrophage phenotype, depending on the environmental stimuli. Because high-density lipoprotein (HDL) cholesterol levels are inversely correlated to cardiovascular disease and since HDL displays anti-inflammatory properties, we investigated whether HDL can affect alternative macrophage differentiation of primary human monocytes in the presence of interleukin (IL)-4, a M2 macrophage polarization driver, in vitro and ex vivo.

METHODS AND RESULTS: M2 macrophages are highly responsive to HDL stimulation, since the expression of pentraxin 3 (PTX3), a well known HDL target gene, is induced by HDL more strongly in M2 macrophages than in control unpolarized resting macrophages (RM). As expected, the expression of M2 markers, such as Mannose Receptor (MR), CD200 Receptor (CD200R), Coagulation factor XIII A1 (F13A1), IL-1 receptor antagonist (IL-1RA) and IL10, was induced in IL-4 polarized M2 macrophages compared to RM. However, incubation with HDL added in vitro did not modulate the gene expression of M2 macrophage polarization markers. Moreover, monocytes isolated from subjects with genetically low HDL levels, carrying ABCA1 or LCAT mutations, differentiated ex vivo into M2 macrophages without any difference in the alternative macrophage marker expression profile.

CONCLUSIONS: These in vitro and ex vivo results indicate that, contrary to mouse macrophages, HDL does not influence macrophage M2 polarization of human monocyte-derived macrophages. Thus, the anti-inflammatory properties of HDL in humans are probably not related to the enhancement of the M2 macrophage phenotype.

Original languageEnglish
Pages (from-to)179-184
Number of pages6
JournalInternational Journal of Cardiology
Volume172
Issue number1
DOIs
Publication statusPublished - 1-Mar-2014

Keywords

  • HDL
  • Human macrophages
  • Alternative polarization
  • Inflammation
  • HIGH-DENSITY-LIPOPROTEIN
  • CHOLESTEROL
  • MACROPHAGES
  • EXPRESSION
  • DISEASE
  • ALPHA
  • CELLS
  • ATHEROSCLEROSIS
  • INFLAMMATION
  • DEFICIENCY

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