IFNβ autocrine feedback is required to sustain TLR induced production of MCP-1 in macrophages

Chemokines, including MCP-1, are crucial to mounting an effective immune response due to their ability to recruit other immune cells. We show that sustained LPS or poly(I:C)-stimulated MCP-1 production requires an IFN beta-mediated feedback loop. Consistent with this, exogenous IFN beta was able to induce MCP-1 transcription in the absence of other stimuli. Blocking IFN beta signaling with Ruxolitinib, a JAK inhibitor, inhibited MCP-1 transcription. The MCP-1 promoter contains potential STAT binding sites and we demonstrate that STAT1 is recruited upon IFNb stimulation. Furthermore we find that IL-10 knockout increases MCP-1 production in response to LPS, which may reflect an ability of IL-10 to repress IFN beta production. Overall, these results show the importance of the balance between IFN beta and IL-10 in the regulation of MCP-1.