Modulation of proliferation, apoptosis and inflammation of Caco-2 epithelial cells and THP-1 macrophage-like monocytes in LPS stimulated co-culture model.

BACKGROUND AND OBJECTIVES Epithelial cells and macrophages play major roles in modulating the state of inlammatory response regulated by intracellular signaling pathways. The aim of this study was to characterize changes in cell proliferation, apoptosis and inflammation related intracellular signalling pathways MAPKs and NF-κB in Caco-2 epithelial cells and THP-1 macrophage-like monocytes contacted and filter-seperated co-cultures in the presence of LPS stimulation. METHODS We assessed the apoptosis and inflammation by measuring caspase-3 activity, TNF-α and IL-10 cytokines, total and phosphorylated forms of intracellular signalling pathway molecules p53, JNK, Jun, ERK, p38, NF-κB p65 and IkB. RESULTS The contacted co-culture of Caco-2 and THP-1 cells represented higher levels of JNK, jun and p38 MAPK pathway proteins associated with cell proliferation, whereas apoptosis related molecule caspase-3 and p53 increased in the filter-separated co-culture condition. Also, the contacted co-culture condition led to proinflammatory changes in NF-κB signalling pathways and cytokine responses with high phosphorylated NF-κB p65 and TNF-α, and low I-κB and IL-10 levels. CONCLUSION Epithelia - monocytes co-culture stimulated with LPS regulated cell proliferation and inflammation in a contact dependent manner, whereas apoptosis was associated with non-contacted cell culture condition. Thus, co-culture models are important models for explaining the immunopathologies in the mucosal areas (Fig. 5, Ref. 30).