Identification of a novel macrophage phenotype that develops in response to atherogenic phospholipids via Nrf2

Alexandra Kadl, Akshaya K. Meher, Poonam R. Sharma, Monica Y. Lee, Amanda C. Doran, Scott R. Johnstone, Michael R. Elliott, Florian Gruber, Jenny Han, Wenshu Chen, Thomas Kensler, Kodi S. Ravichandran, Brant E. Isakson, Brian R. Wamhoff, Norbert Leitinger

Research output: Contribution to journalArticle

Abstract

Rationale: Macrophages change their phenotype and biological functions depending on the microenvironment. In atherosclerosis, oxidative tissue damage accompanies chronic inflammation; however, macrophage phenotypic changes in response to oxidatively modified molecules are not known. Objective: To examine macrophage phenotypic changes in response to oxidized phospholipids that are present in atherosclerotic lesions. Methods and results: We show that oxidized phospholipid-treated murine macrophages develop into a novel phenotype (Mox) that is strikingly different from the conventional M1 and M2 macrophage phenotypes. Compared to M1 and M2, Mox macrophages show a different gene expression pattern, as well as decreased phagocytotic and chemotactic capacity. Treatment with oxidized phospholipids induces both M1 and M2 macrophages to switch to the Mox phenotype. Whole-genome expression array analysis and subsequent gene ontology clustering revealed that the Mox phenotype was characterized by abundant overrepresentation of Nrf2-mediated expression of redox-regulatory genes. In macrophages isolated from Nrf2-/- mice, oxidized phospholipid-induced gene expression and regulation of redox status were compromised. Moreover, we found that Mox macrophages comprise 30% of all macrophages in advanced atherosclerotic lesions of low-density lipoprotein receptor knockout (LDLR-/-) mice. Conclusions: Together, we identify Nrf2 as a key regulator in the formation of a novel macrophage phenotype (Mox) that develops in response to oxidative tissue damage. The unique biological properties of Mox macrophages suggest this phenotype may play an important role in atherosclerotic lesion development as well as in other settings of chronic inflammation.

Original languageEnglish (US)
Pages (from-to)737-746
Number of pages10
JournalCirculation research
Volume107
Issue number6
DOIs
StatePublished - Sep 17 2010

Keywords

  • Nrf2
  • atherosclerosis
  • macrophages
  • oxidized phospholipids

ASJC Scopus subject areas

  • Physiology
  • Cardiology and Cardiovascular Medicine

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  • Cite this

    Kadl, A., Meher, A. K., Sharma, P. R., Lee, M. Y., Doran, A. C., Johnstone, S. R., Elliott, M. R., Gruber, F., Han, J., Chen, W., Kensler, T., Ravichandran, K. S., Isakson, B. E., Wamhoff, B. R., & Leitinger, N. (2010). Identification of a novel macrophage phenotype that develops in response to atherogenic phospholipids via Nrf2. Circulation research, 107(6), 737-746. https://doi.org/10.1161/CIRCRESAHA.109.215715