Epithelial Cells Attenuate Toll-Like Receptor-Mediated Inflammatory Responses in Monocyte-Derived Macrophage-Like Cells to Mycobacterium tuberculosis by Modulating the PI3K/Akt/mTOR Signaling Pathway

Figure 6

Impact of PI3K/Akt/GSK3β/mTOR signaling in U937 cells in response to H37Rv infection. In the presence or absence of PI3K inhibitor LY294002, the coculture model of A549/U937 cells was infected with H37Rv mycobacteria from the upper chamber (A549 cells, AI), lower chamber (U937 cells, UI), or both chambers (A549 and U937 cells, CI) at a MOI of 3 for 18 h before the culture medium and U937 cells were harvested for analysis. (a) Representative blots of immunoblotting assay for the indicated components of PI3K/Akt/GSK3β/mTOR signaling showed an involvement of Akt, GSK3β, and mTOR signaling in U937 cells of the coinfection model. (b) The fold of changes of proteins of interest in (a) semiquantitatively determined by densitometric assay using ImageJ software Fiji from three independent experiments; the ability of A549 cell-mediated reduction of Akt, GSK3β, and mTOR signaling activity in U937 cells was lost in the presence of LY294002. Error bars represent the standard deviation (SD) from three independent experiments. Compared to noninfection (NI) control, and ; compared to the absence of LY294002, and . NI: noninfected control; AI: infection was performed on A549 cell alone; UI: infection was performed on U937 alone; CI: infection was performed on both A549 cells and U937 cells.

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