This study investigates the differentiation of monocytes into M1 and M2 macrophages, highlighting the role of specific growth factors and cytokines. The methodology includes the use of GM-CSF and M-CSF to polarize monocytes, followed by analysis of their morphological changes and cytokine production.
Specific growth factors and cytokines regulate the differentiation of monocytes — innate immune system cells — into pro-inflammatory M1 or anti-inflammatory M2 macrophages.
To study monocyte differentiation, seed peripheral blood mononuclear cells in a plastic multi-well plate containing a suitable medium. Incubate to allow the monocytes to attach to the plate surface while the non-adherent mononuclear cells remain suspended. Remove the non-adherent cells.
Add medium containing growth factor granulocyte-macrophage colony-stimulating factor, GM-CSF, to one set of wells and medium containing macrophage colony-stimulating factor, M-CSF, to the other.
GM-CSF binds to its heterodimeric receptor on the monocyte cell surface, leading to monocyte expansion and differentiation into M1-like macrophages, coupled with pro-inflammatory cytokine release.
M-CSF binds to its homodimeric receptor on the monocyte cell surface, triggering monocyte proliferation, differentiation into M2-like macrophages, and anti-inflammatory cytokine release.
Incubate the M1-like macrophages with lipopolysaccharide, LPS, and the cytokine Interferon‐gamma, IFN‐γ.
LPS and IFN‐γ treatment yields fully polarized and mature pro-inflammatory M1 macrophages with enhanced pro-inflammatory cytokine and reactive oxygen species release.
Conversely, incubation with interleukin-4 stimulates the maturation and polarization of M2-like macrophages into the anti-inflammatory M2 phenotype, along with enhanced anti-inflammatory cytokine production.
Visualize the macrophages under a light microscope. M1 macrophages appear elongated and stretched, while M2 macrophages exhibit a rounded morphology.
To initiate macrophage differentiation, dilute the cells to a 5 x 106 cells per milliliter of serum-free medium concentration, and seed 2 milliliters of cells into individual wells of a 6-well plate. Place the plate in the cell culture incubator for two to three hours to allow the cells to adhere to the well bottoms.
At the end of the incubation, wash the wells three times with 1 milliliter of serum-free medium per wash, and add 2 milliliters of complete RPMI medium supplemented with 50 nanograms per milliliter of GM-CSF, or 50 nanograms per milliliter of M-CSF, for M1 or M2 differentiation respectively, to each well of adherent cells.
Three days after polarization initiation, carefully replace 1 milliliter of supernatant from each well, with 1 milliliter of fresh complete medium supplemented with the appropriate growth factors.
On day 6 of culture, add 50 nanograms per milliliter of interferon-gamma and 10 nanograms per milliliter of LPS to the GM-CSF-treated wells, and 20 nanograms per milliliter of IL4 to the M-CSF-treated wells.
Check the morphology of the monocyte-derived cell cultures regularly by light microscopy to ensure that the smaller monocytes are differentiating into larger macrophage-like cells.
繁體中文
