Signaling pathways involved in tumor necrosis factor α‐induced upregulation of the taurine transporter in Caco‐2 cells

Abstract

We have previously demonstrated that the taurine uptake and transporter (TAUT) mRNA expression were upregulated by tumor necrosis factor α (TNF-α) in Caco-2 cells. In this present study, the signaling molecules related to this upregulation were investigated. Pyrrolidine dithiocarbamate, a nuclear factor κB (NF-κB) inhibitor, repressed the upregulation of taurine uptake and TAUT mRNA expression. A reporter assay revealed that TNF-α-induced TAUT transcriptional activity through the NF-κB consensus-like sequence in the human TAUT promoter region. An electrophoretic mobility shift assay showed that NF-κB could bind to the NF-κB consensus-like sequence. The anti-TNF receptor 1 (TNFR1) antibody, but not the TNF receptor 2 (TNFR2) antibody, repressed this upregulation