Clostridium butyricum Supernatant Regulates the Expression of RORγt in HCT-116 Cells by Inhibiting the TLR2/MyD88/NF-κB Signaling Pathway.

In this study, we treated HCT-116 cells with Clostridium butyricum (C. butyricum) supernatant and observed its effects on the TLR2/MyD88/NF-κB signaling pathway and RORγt, to further explore the possible immune regulatory mechanism of C. butyricum. Our results showed that C. butyricum supernatant downregulated the mRNA and protein levels of TLR2, MyD88, NF-κBp65, and RORγt in HCT-116 cells and the protein levels of phospho-NF-κBp65. Partial blockage of TLR2 by CD282 weakened the inhibitory effects of C. butyricum supernatant on the above pathway components. Those component levels were still inhibited by C. butyricum supernatant after Pam3CSK4 activation of TLR2. In summary, C. butyricum supernatant can inhibit the TLR2/MyD88/NF-κB signaling pathway and the expression of RORγt in HCT-116 cells. These effects are at least partly achieved through inhibition of TLR2.