Neutralization of EGFR resulted in a complete rescue of the suppressed PICD in AREG-stimulated monocytes and, more strikingly, selectively increased the PICD of infected, unstimulated CBMO but not PBMO (Figures 5(a) and 5(b)).
As shown in Figure 6, loss of AREG had no effect in control cells and did not affect PICD of PBMO. However, in line with our previous results, the proportion of CBMO that underwent PICD was found significantly increased upon AREG inhibition.
coli infection leads to TNF-[alpha] release, while PBMO displayed a distinctly increased TNF-[alpha] release compared to CBMO .
In line with the published literature, our data unveil 3-fold increased memFasL levels and 2-fold increased sFasL levels in response to infection in PBMO as compared to CBMO [45, 58, 59] which potentially contribute to the diminished PICD of neonatal monocytes (Figures 3(a) and 3(b)).
coli: Escherichia coli EGF: Epidermal growth factor EGFR: Epidermal growth factor receptor ELISA: Enzyme-linked immunosorbent assay FasL: Fas ligand FasR: Fas receptor FBS: Fetal bovine serum FITC: Fluorescein isothiocyanate FSC: Forward scatter IU: International unit IgG: Immunoglobulin G MAPK: Mitogen-activated protein kinase MFI: Mean fluorescence index MMP-2: Matrix metalloproteinase 2 MMP-9: Matrix metalloproteinase 9 MOI: Multiplicity of infection PBMC: Peripheral blood mononuclear cells PBMO: CD14-positive peripheral blood monocytes from adults PBS: Phosphate-buffered saline PBS-T: Phosphate-buffered saline Triton-X 100- supplemented PI: Propidium iodide PICD: Phagocytosis-induced cell death RT: Room temperature SD: Standard deviation S.