Molecular and cellular characterization of macrophage-like polarization states
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Citation
Abstract
BACKGROUND: Macrophages are necessary for body homeostasis, being essential in the innate and adaptive immune system. They contribute to the removal of cellular debris and pathogen clearance, as well as being involved in regulating inflammation and tissue repair. High plasticity of these cells allows the phenotype of a macrophage to be determined on its environment resulting in either a pro-inflammatory phenotype, classified as M1, or a pro-fibrotic phenotype, classified as M2.
OBJECTIVE: This study focuses on investigating and characterizing the differentiation potential of two myelogenous leukemia cell lines, U937 and K562, towards a macrophage-like state.
METHODS: The aim was to establish conditions to promote differentiation of U937 and K562 cell lines into M1- and M2-like polarized macrophages. Each protocol was set independently by determining appropriate timepoints and stimuli concentrations. Cellular characterization was assessed immunophenotypically through flow cytometry analysis, and morphologically through Giemsa staining.
RESULTS: Our findings show that successful differentiation of U937 into polarized M1- and M2-like macrophage phenotypes was achieved upon specific stimuli. However, a clear polarization towards M1- or M2-like phenotypes was not observed in K562 cells, as the expected surface markers were absent.
CONCLUSION: In this study, we delineated an optimized reproducible protocol to differentiate U937 into polarized macrophages. We also made significant progress in understanding and characterizing the differentiation steps of K562 cells, although additional refinement is required to validate M1- and M2-like polarization in this cell
line.
Description
2025