Low human and murine Mcl-1 expression leads to a pro-apoptotic plaque phenotype enriched in giant-cells

Sci Rep. 2019 Oct 10;9(1):14547. doi: 10.1038/s41598-019-51020-3.

Abstract

The anti-apoptotic protein myeloid cell leukemia 1 (Mcl-1) plays an important role in survival and differentiation of leukocytes, more specifically of neutrophils. Here, we investigated the impact of myeloid Mcl-1 deletion in atherosclerosis. Western type diet fed LDL receptor-deficient mice were transplanted with either wild-type (WT) or LysMCre Mcl-1fl/fl (Mcl-1-/-) bone marrow. Mcl-1 myeloid deletion resulted in enhanced apoptosis and lipid accumulation in atherosclerotic plaques. In vitro, Mcl-1 deficient macrophages also showed increased lipid accumulation, resulting in increased sensitivity to lipid-induced cell death. However, plaque size, necrotic core and macrophage content were similar in Mcl-1-/- compared to WT mice, most likely due to decreased circulating and plaque-residing neutrophils. Interestingly, Mcl-1-/- peritoneal foam cells formed up to 45% more multinucleated giant cells (MGCs) in vitro compared to WT, which concurred with an increased MGC presence in atherosclerotic lesions of Mcl-1-/- mice. Moreover, analysis of human unstable atherosclerotic lesions also revealed a significant inverse correlation between MGC lesion content and Mcl-1 gene expression, coinciding with the mouse data. Taken together, these findings suggest that myeloid Mcl-1 deletion leads to a more apoptotic, lipid and MGC-enriched phenotype. These potentially pro-atherogenic effects are however counteracted by neutropenia in circulation and plaque.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • 3T3 Cells
  • Animals
  • Apoptosis*
  • Atherosclerosis / genetics
  • Atherosclerosis / metabolism
  • Cell Differentiation
  • Gene Deletion
  • Giant Cells / cytology*
  • Humans
  • Immunohistochemistry
  • Lipids / chemistry
  • Macrophages / metabolism
  • Male
  • Mice
  • Mice, Inbred C57BL
  • Mice, Transgenic
  • Myeloid Cell Leukemia Sequence 1 Protein / genetics
  • Myeloid Cell Leukemia Sequence 1 Protein / metabolism*
  • Neutrophils / metabolism
  • Phenotype
  • Plaque, Atherosclerotic / metabolism

Substances

  • Lipids
  • MCL1 protein, human
  • Mcl1 protein, mouse
  • Myeloid Cell Leukemia Sequence 1 Protein