A novel CD14high CD16high subset of peritoneal macrophages from cirrhotic patients is associated to an increased response to LPS

• First description of a CD14highCD16high M-DM subset in ascites fluid of cirrhotic patients.
• Basal hyperactivation of ERK and c-Jun correlates with CD14CD16 high expressing M-DM subsets.
• Basal hyperactivation of PKB correlates with CD16 low expressing M-DM.
• CD14 high-expressing subsets may be responsible for the enhanced response to LPS.
• Ascites M-DM produce higher amounts of IL-6, IL-10 and TNF-α, while lower levels of IL-1β and IL-12.

The aim of this study was to characterize monocyte-derived macrophages (M-DM) from blood and ascites of cirrhotic patients comparatively with those obtained from blood of healthy controls. The phenotypic profile based on CD14/CD16 expression was analyzed by flow cytometry. Cells were isolated and stimulated in vitro with LPS and heat killed Candida albicans. Phosphorylation of ERK, c-Jun, p38 MAPK, and PKB/Akt was analyzed by Western blotting. A novel CD14highCD16high M-DM subpopulation is present in ascites (∼33%). The CD14++CD16+ intermediate subset is increased in the blood of cirrhotic patients (∼from 4% to 11%) and is predominant in ascites (49%), while the classical CD14++CD16− subpopulation is notably reduced in ascites (18%). Basal hyperactivation of ERK and JNK/c-Jun pathways observed in ascites M-DM correlates with CD14/CD16 high expressing subsets, while PI3K/PKB does it with the CD16 low expressing cells. In vitro LPS treatment highly increases ERK1/2, PKB/Akt and c-Jun phosphorylation, while that of p38 MAPK is decreased in M-DM from ascites compared to control blood M-DM. Stimulation of healthy blood M-DM with LPS and C. albicans induced higher phosphorylation levels of p38 than those from ascites. Regarding cytokines secretion, in vitro activated M-DM from ascites of cirrhotic patients produced significantly higher amounts of IL-6, IL-10 and TNF-α, and lower levels of IL-1β and IL-12 than control blood M-DM. In conclusion, a new subpopulation of CD14highCD16high peritoneal M-DM has been identified in ascites of cirrhotic patients, which is very sensitive to LPS stimulation.

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