Bone Morphogenetic Protein 6 Attenuates Psoriasis Pathogenesis by Suppressing Th17 Cell Differentiation

Bone morphogenetic protein (BMP) signaling has multiple functions in immune cells, especially in the differentiation of T cells. Previously, we found that BMP6 can dramatically promote the IFN-γ production in Th1. However, the interactions between BMP6 and Th17 cells remain poorly characterized. The evidence implicates dysregulated Th17 cell differentiation as a pivotal mechanism in psoriatic pathogenesis, yet the therapeutic potential of BMP6 in this autoimmune disease needs to be further explored. This study aimed to evaluate the potentially beneficial role of BMP6 in the Th17-induced psoriatic models and investigate its possible mechanisms. Th17 cells were intervened with BMP6 in vitro. The differentiation of Th17 was observed through multi-platform assessment combining flow cytometry, qRT-PCR, and ELISA. Signaling pathway activation was evaluated by Western blotting. RNAseq was used to further discover the impact of BMP6 on Th17. For in vivo experiments, the psoriatic model of C57BL/6 mice was established and treated with BMP6 i.d., and the Th17 cells were evaluated by flow cytometry. BMP6 treatment suppressed Th17 differentiation via the Smad1/5/9 pathway and impaired mitochondrial metabolism of Th17. In the imiquimod-induced psoriatic murine model, pharmacological BMP6 administration significantly attenuated disease progression and downregulated pathogenic Th17 cell frequency in lesional skin. Our finding elucidates the potential mechanism underlying the inhibitory effects of BMP6 in Th17-induced autoimmune diseases and furnish a theoretical foundation for its clinical application.