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C‐Reactive Protein polarizes human macrophages to a M1 phenotype
Author(s) -
Devaraj Sridevi,
Jialal Ishwarlal
Publication year - 2011
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.25.1_supplement.616.5
Inflammation is pivotal in atherosclerosis and macrophages are key cells. Monocytes can develop into classically (M1) or alternatively (M2) activated cells. Several studies point to a pro‐inflammatory role for C‐reactive protein (CRP), but there is no data examining the direct effect of CRP on macrophage phenotype and this was the aim of the study. Monocytes were incubated with CRP(0–50ug/mL) and differentiated into macrophages for 7 days. Phenotypic characterization of M1 and M2 cells from subjects was done using flow cytometry. CRP treatment increased the population of M1 macrophages (TNF/IL12/CCR2/IL‐1); boiled CRP had no effect. Human CRP injection in rats in vivo increased polarization to M1 macrophages when compared to HuSA. When macrophages were primed with IL‐4 to a M2 phenotype and then CRP was added, this significantly increased secretion of the pro‐inflammatory TNF‐á, MCP‐1 and IL‐1 and conversion of macrophages from M2 to M1 type. CRP failed to prime monocytes to an M1 phenotype in presence of CD32siRNA/CD64 siRNA/DN‐NFKb. These results further support a role for CRP in promoting differentiation of monocytes towards a pro‐inflammatory M1 phenotype via Fc gamma receptors and NFKb.