Figure 4
Fig. 4. Pollution-induced trained immunity is characterized by enhanced secretion of inflammatory mediators in monocytes. Impact of in vitro overnight exposure to the particulate pollutant SRM1648a in monocytes was assessed 6 days later by measuring the levels of pro-inflammatory cytokines including TNF, IL-6, G-CSF, GM-CSF, and IL-1β upon stimulation with LPS or HDM (A). The levels of chemokines, IL-8, MIP-1α, MIP-1β, GRO, and IP-10 were also measured in monocytes after training with SRM1648a pollutant and then LPS or HDM stimulation (B). Training with the SRM1648a pollutant did not induce MCP-1 and MDC secretion; whereas MCP-3 level was increased in monocytes stimulated with HDM but not LPS (C). Release of FGF-2 and EGF was higher in supernatants from monocytes trained with the SRM1648a pollutant compared to untrained control group after LPS or HDM stimulation (C). The data were obtained from 2 independent Luminex experiments in which statistical significance was determined using non-parametric Wilcoxon sum test. Blue dots represent the average values of Luminex data form monocyte culture supernatants obtained from 5 donors without training with SRM1648a pollutant (control group). Red dots represent the average values of Luminex data form monocyte culture supernatants obtained from the same 5 donors as of control group but after training with SRM1648a. EGF: Epidermal Growth Factor; FGF 2: Fibroblast Growth Factor 2; G-CSF: Granulocyte Colony Stimulating Factor; GM-CSF: Granulocyte-Monocyte Colony Stimulating Factor; GRO-α: Growth-Related Oncogene Alpha; IP10: Interferon gamma-induced Protein 10; MCP: Monocyte-Chemotactic Protein; MDC: Macrophage-Derived Chemokine; MIP: Macrophage Inflammatory Protein.