Chaetoglobosin F, a small molecule compound, possesses immunomodulatory properties on bone marrow-derived dendritic cells via TLR9 signaling pathway.

Chaetoglobosin F (Cha F), a cytochalasan-based alkaloid, was obtained from the EtOAc extract of a solid culture of Chaetomium globosum IFB-E019. Dendritic cells (DCs), the most potent antigen presenting cells, are considered as the major target in the modulation of excessive immune responses. Recognition of CpG-DNA by Toll-like receptor 9 (TLR9) on DCs is an important step in the pathogenesis of autoimmune diseases. However, the effect of Cha F on the maturation and immunostimulatory function of CpG-stimulated DCs remains unclear. This study investigated the effects of Cha F on bone marrow (BM)-derived DCs. We found that Cha F inhibits the CpG-induced DCs maturation and function by suppressing the expression of surface molecules (CD40, CD80, CD86 and MHC-II), reducing the production of cytokines and chemokines (IL-12 and CXCL-10), inhibiting the CpG-induced DCs-elicited allogeneic T-cell proliferation, and impairing the migration ability to chemokines. The Cha F-treated DCs were highly efficient at Ag capture, via mannose receptor-mediated endocytosis. Additionally, Cha F was also demonstrated to inhibit CpG-induced activation of MAPKs (p38 and JNK, but not ERK) and the nuclear translocation of NF-κB and STAT1. Furthermore, we confirmed that Cha F was able to suppress TLR9 expression of CpG-induced DCs. Collectively, these findings provide novel insight into the immunopharmacological functions of Cha F, especially with regard to their impact on CpG-induced DCs. These immunosuppressive properties of Cha F may prove useful in controlling DCs-associated autoimmune and/or inflammatory diseases.