Folate Receptor Expression by Human Monocyte-Derived Macrophage Subtypes and Effects of Corticosteroids

Folate Receptor Expression by Human Monocyte-Derived Macrophage Subtypes and Effects of Corticosteroids

Warmink, Kelly (University Medical Center Utrecht)
Siebelt, Michiel (Erasmus MC)
Low, Philip S. (Purdue University)
Riemers, Frank M. (Universiteit Utrecht)
Wang, Bingbing (Purdue University)
Plomp, Saskia G.M. (Universiteit Utrecht)
Tryfonidou, Marianna A. (Universiteit Utrecht)
van Weeren, P. René (Universiteit Utrecht)
Weinans, H.H. (TU Delft Biomaterials & Tissue Biomechanics; University Medical Center Utrecht)
Korthagen, Nicoline M. (University Medical Center Utrecht; Universiteit Utrecht)

2022

OBJECTIVE: Folate receptor beta (FR-β) has been used as a clinical marker and target in multiple inflammatory diseases, including osteoarthritis (OA) and rheumatoid arthritis (RA). However, the conditions under which FR-β+ macrophages arise remain unclear and could be affected by corticosteroids. Therefore, we studied FR-β expression in vitro in macrophage subtypes and determined their response to triamcinolone acetonide (TA), a clinically often-used corticosteroid. DESIGN: Human monocyte-derived macrophages were differentiated to the known M0, M1, or M2 macrophage phenotypes. The phenotype and FR-β expression and plasticity of the macrophage subtypes were determined using flow cytometry, reverse transcription-quantitative polymerase chain reaction (RT-qPCR), and enzyme-linked immunosorbent assay (ELISA). RESULTS: FR-β expression was low in granulocyte-macrophage colony-stimulating factor (GM-CSF)-generated (M1-like) macrophages and high in macrophage colony-stimulating factor (M-CSF)-generated (M0 and M2-like) macrophages. FR-β expression remained high once the M0 or M2 macrophages were stimulated with pro-inflammatory stimuli (interferon-γ plus lipopolysaccharide) to induce M1-like macrophages. On the contrary, anti-inflammatory TA treatment skewed GM-CSF macrophage differentiation toward an M2 and FR-β+ phenotype. CONCLUSIONS: As corticosteroids skewed monocytes toward an FR-β-expressing, anti-inflammatory phenotype, even in an M1 priming GM-CSF environment, FR-β has potential as a biomarker to monitor success of treatment with corticosteroids. Without corticosteroid treatment, M-CSF alone induces high FR-β expression which remains high under pro-inflammatory conditions. This explains why pro-inflammatory FR-β+ macrophages (exposed to M-CSF) are observed in arthritis patients and correlate with disease severity.

corticosteroids
disease marker
FR-beta
M1/M2
macrophages

http://resolver.tudelft.nl/uuid:357b960b-4632-4135-8e77-ada1f01dfded

https://doi.org/10.1177/19476035221081469

1947-6043

Cartilage, 13 (1)

Institutional Repository

journal article

© 2022 Kelly Warmink, Michiel Siebelt, Philip S. Low, Frank M. Riemers, Bingbing Wang, Saskia G.M. Plomp, Marianna A. Tryfonidou, P. René van Weeren, H.H. Weinans, Nicoline M. Korthagen