At 24 h, the lipoteichoic acid (LTA) and LPS treatments showed concentration dependence (Figure 6). iron exporter. (-)-Epigallocatechin and lipopolysaccharides (LPSs) acted similarly on THP-1 cells, but the rates of the alterations of the examined proteins were different. LPS was more effective in increasing the pro-inflammatory cytokine production, meanwhile it caused less dramatic alterations in iron metabolism. LPS-treated cells produced a smaller amount of pro-inflammatory cytokines, but caused remarkable elevation of both cytosolic and mitochondrial iron storage proteins and intracellular iron content compared to LPS. These results prove that LPS molecules from different bacterial sources alter diverse molecular mechanisms in macrophages that prepossess the outcome of the bacterial infection. and Gram-negative bacterial strains, and LTA purified from the Gram-positive bacterium to reveal the differences between their effects on pro-inflammatory cytokine (IL-1, IL-6 and TNF) production, on soluble FKN secretion and on the iron transport and storage of THP-1 human monocytes. We found (-)-Epigallocatechin that LPS showed the most powerful effect on pro-inflammatory cytokine and FKN secretions and LPS was the least effective on IL-6 secretion, while LTA was found to have almost no effect on TNF- synthesis. The action of Gram-negative and Gram-positive bacterial cell wall components was time and concentration dependent. Although (-)-Epigallocatechin the two different types of LPS affected the iron content and heme concentration of THP-1 cells similarly, we found fundamental differences between the effects of LTA and LPS treatments on the expression of iron transport and storage proteins. Based on these results, we suppose that not only the type but the source of the bacterial cell wall components are essential in the mechanism of action on macrophages, considering inflammatory as well as iron metabolism regulatory activities. 2. Results 2.1. Bacterial Cell Wall Components Trigger the Secretion of Pro-Inflammatory Cytokines in THP-1 Cells Differently Bacterial infections activate different Toll-like receptors (TLRs) on (-)-Epigallocatechin macrophages and regulate the expression of pro-inflammatory cytokines via the NFB signaling pathway, but it seems that various bacterial strains may influence the production of inflammatory molecules differently [10,11]. We examined the IL-6, IL-1 and TNF- secretion of THP-1 cells treated with three bacterial cell wall components, mimicking infections. We utilized lipoteichoic acid (LTA) from and lipopolysaccharide (LPS) from and LTA, LPS and LPS. (B) IL-1 production of THP-1 cells treated with LTA and LPS isolated from different sources. (C) TNF- secretion of LTA- and LPS-treated THP-1 cells. The columns represent mean values and error bars represent standard deviation (SD) of three independent determinations (= 3). ELISA measurements were carried out in triplicate in each independent experiment. An asterisk * indicates 0.05 compared to the controls. A cross ? indicates 0.05 compared to LTA treatment and a double cross ? shows 0.05 compared to LPS treatment. We revealed that LPS was the most powerful activator of pro-inflammatory cytokine secretion at both examined time points (Figure 1ACC) compared to LPS and LTA. It seemed that LTA caused a weak inflammatory signal in the THP-1 cells in terms of IL-1 and TNF- secretion (Figure 1B,C), but was more effective in the case of IL-6 production compared to LPS (Figure 1A). These results suggest that in the case of Gram-positive infections, IL-6 is probably the major mediator of the inflammation, while Gram-negative bacteria primarily trigger TNF- secretion. 2.2. Lipopolysaccharide (LPS) and Lipoteichoic Acid (LTA) Activate Fractalkine Secretion and CX3CR1 Expression of THP-1 Cells Fractalkine (FKN) is released by endothelial cells in bacterial infection . FKN is involved in the recruitment of monocytes to the site of infection  and binds to its receptor CX3CR1 expressed by macrophages . The CX3CR1 signaling also regulates the NFB signaling pathway, affecting inflammatory functions of macrophages . Although LTA treatment increased FKN secretion of the THP-1 cells, the two LPS cell wall components were significantly more effective in Mouse monoclonal to ALCAM triggering FKN production (Figure 2A), suggesting that LPS generates a stronger immune response compared to LTA. We also found that, although at lower concentrations LPS was more effective on the FKN production of THP-1 cells, at a 1000 ng/mL concentration, there was no significant difference between the effects of and LPS (Figure 2A). Open in a separate window Figure 2 Concentration measurement of fractalkine of lipopolysaccharide (LPS)- and lipoteichoic acid (LTA)-treated THP-1 cells, relative mRNA expression and Western blot.