Polarized macrophage functions are affected differentially after CSF-1R inhibition with PLX5622.

PLX5622 is a colony stimulating factor 1 receptor (CSF-1R) inhibitor that is known to deplete microglial cells in vivo. Recently its effects on macrophages (Mφ) were also observed in vivo. Therefore, we performed this study to assess its in vitro effects on the differentiation and functions of polarized Mφ derived from different tissues.

Granulocyte macrophage colony stimulating factor exerts dominant effects over macrophage colony stimulating factor during macrophage differentiation in vitro to induce an inflammatory phenotype.

Background: Macrophages (Mφ) can exist along a spectrum of phenotypes that include pro-inflammatory (M1) or anti-inflammatory (M2) immune cells. Mφ colony stimulating factor (M-CSF) and granulocyte Mφ colony stimulating factor (GM-CSF) are cytokines important in hematopoiesis, polarization and activation of Mφ.

Methods And Results: To gain a greater understanding of the relationship between GM-CSF and M-CSF, we investigated an in vitro model of differentiation to determine if GM-CSF and M-CSF can antagonize each other, in terms of Mφ phenotype and functions.