Multi-target regulation of pro-inflammatory cytokine production by transcription factor Blimp-1.

OBJECTIVE: Cytokine storm syndrome is a fatal condition related to infectious and autoimmune diseases. Here, we aim to investigate the regulatory mechanisms of Blimp-1 on multiple cytokine production. METHODS: The Blimp1 shRNA was transfected into RAW264.7 macrophages, followed by Toll-like receptor (TLR) ligand stimulation. The mRNA and protein levels of cytokines were detected by real-time PCR and flow cytometric bead array. The nuclear translocation of AP-1 and NF-κB p65 was measured by immunofluorescence staining. The transcriptional activity was detected by luciferase reporter assay with 5 × NF-κB reporter or with IL6 promoter reporter. RESULTS: Blimp-1 significantly inhibited the expression and secretion of IL-1ß, IL-6, and IL-18 in macrophages during stimulation with a variety of TLR ligands. The immunofluorescence staining results showed that Blimp-1 strictly controlled the nuclear translocation of NF-κB p65 in LPS-challenged macrophages. Furthermore, Blimp-1 directly inhibited the transcriptional activity of NF-κB and the transcription of IL6 gene. CONCLUSION: Blimp-1 represses the production of multiple pro-inflammatory cytokines by directly binding the genomic region and restricting the nuclear translocation and transcriptional activity of NF-κB. This finding may provide potential therapeutic strategies for the cytokine storm-related diseases.