Plasticity of Human THP–1 Cell Phagocytic Activity during Macrophagic Differentiation

Abstract

Studies of the role of macrophages in phagocytosis are of great theoretical and practical importance for understanding how these cells are involved in the organism's defense response and in the development of various pathologies. Here we investigated phagocytic plasticity of THP-1 (acute monocytic human leukemia) cells at different stages (days 1, 3, and 7) of phorbol ester (PMA)-induced macrophage differentiation. Analysis of cytokine profiles showed that PMA at a concentration of 100 nM induced development of the proinflammatory macrophage population. The functional activity of macrophages was assessed on days 3 and 7 of differentiation using unlabeled latex beads and latex beads conjugated with ligands (gelatin, mannan, and IgG Fc fragment) that bind to the corresponding specific receptors. The general phagocytic activity increased significantly (1.5-2.0-fold) in the course of differentiation; phagocytosis occurred mostly through the Fc receptors, as shown previously for M1 macrophages. On day 7, the levels of phagocytosis of gelatin- and Fc-covered beads were high; however, the intensity of ingestion of mannan-conjugated beads via mannose receptors increased 2.5-3.0-fold as well, which indicated formation of cells with an alternative phenotype similar to that of M2 macrophages. Thus, the type and the plasticity of phagocytic activity at certain stages of macrophage differentiation can be associated with the formation of functionally mature morphological phenotype. This allows macrophages to exhibit their phagocytic potential in response to specific ligands. These data are of fundamental importance and can be used to develop therapeutic methods for correcting the M1/M2 macrophage ratio in an organism.

Modulation of calcium signaling pathway by hepatitis C virus core protein stimulates NLRP3 inflammasome activation

“…We assessed the formation of ASC-specks in cells treated with rHCV-core or purified recombinant green fluorescence protein (rGFP, control). As phagocytic cells, THP-1 macrophages readily internalize cell-free macromolecules in a fashion similar to KCs [27, 55], and immunofluorescence staining of recombinant core or fluorescence analysis of rGFP in cells demonstrated the uptake of each protein by treated THP-1 macrophages. We found that rHCV-core but not rGFP triggered ASC-speck formation after cell uptake (Fig 4C).…”

Macrophages Modulated by Red/NIR Light: Phagocytosis, Cytokines, Mitochondrial Activity, Ca2+ Influx, Membrane Depolarization and Viability

“…After inoculation into 96-well microtiter plates at 1 9 10 5 cells per well, macrophages were incubated in colorless DMEM under normal conditions for 24 h prior to the light treatment. Then, macrophages were incubated with zymosan (Sigma-Aldrich, China) for phagocytosis stimulation (100 nM (37)) and/or were irradiated. After 3 or 24 h, the phagocytosis activity was assessed using nitro blue tetrazolium (NBT) reduction test in cells with zymosan.…”

“…The light-evoked phagocytosis was compared with activation by an effective dose of zymosan, a known pharmacological stimulator of phagocytosis (Kurynina et al, 2018). Zymosan is used in standard techniques to stimulate the maximum activity of macrophages (e.g., in a generally accepted technique of NBT).…”

“…1a and the representative images in Figure S2, see Supporting Information). The light-evoked phagocytosis was compared with that activated by an effective dose of zymosan, a known pharmacological stimulator of phagocytosis and respiratory burst in macrophages (37). The maximal enhancement of a respiratory burst caused by zymosan was 215% (by 3.15 times), when measured 3 h after application, both with and without light irradiation (Fig.…”

Carnosine Stimulates Macrophage-Mediated Clearance of Senescent Skin Cells Through Activation of the AKT2 Signaling Pathway by CD36 and RAGE

“…THP-1 cells were cultured in RPMI medium 1640 (GIBCO, Life Technologies Corporation, NY, United States) containing 10% FBS at 37°C in a humidified atmosphere containing 5% CO 2 . Macrophages (Mφ) were acquired from THP-1 cells by induction with 200 ng/ml PMA for 6 h as previously described (Tsai et al, 2017;Kaneko et al, 2018;Kurynina et al, 2018) but with minor modification.…”