Transcription factor specificity protein 1 modulates TGFβ1/Smad signaling to negatively regulate SIGIRR expression by human M1 macrophages stimulated with substance P

In conclusion, TGFβ1 may be an intermediary between SP/NK1R activation and SIGIRR expression in Sp1 siRNA-transfected macrophages. In addition, Sp1 modulates TGFβ1/Smad signaling and negatively regulates SIGIRR protein production by macrophages after SP stimulation.