Danthron as a novel IL-6R agonist promotes thrombopoiesis via the SRC/RAS/MAPK pathway

This study aimed to investigate the effects of danthron on promoting megakaryocyte (MK) differentiation and alleviating thrombocytopenia, as well as to elucidate its underlying mechanisms.

Cell proliferation and apoptosis of Meg-01 and K562 cells were evaluated by CCK-8, LDH release, and apoptosis assays. MK differentiation was assessed by Giemsa staining, phalloidin staining, and flow cytometry. A thrombocytopenia mouse model was induced by 4 Gy irradiation and treated intraperitoneally with danthron for 12 days, followed by hematological, histopathological, MK differentiation, and tail bleeding analyses. Potential targets and pathways were explored using network pharmacology, molecular docking, GO/KEGG enrichment, Western blotting, and inhibitor validation.

Danthron effectively promoted MK differentiation in vitro, inducing the expression of MK differentiation-related transcription factors NF-E2, RUNX1, MEIS1, and HIF-1β, without exhibiting significant cytotoxicity. In addition, danthron markedly accelerated the recovery of MK progenitors, MKs, and platelet levels in thrombocytopenic mice, and shortened tail bleeding time. These effects were associated with danthron directly targeting IL-6R and activating the downstream SRC/RAS/MAPK signaling pathway, whereas inhibition of IL-6R or ERK abrogated these effects.

This study uncovered danthron as a novel natural small-molecule agonist of IL-6R and demonstrated its therapeutic potential in thrombocytopenia. The effect of danthron is mediated by its capacity to promote MK differentiation and induce platelet production through targeting of IL-6R and activation of the downstream SRC/RAS/MAPK signaling pathway. These results highlight danthron as a promising candidate for thrombocytopenia therapy and underscore the therapeutic potential of targeting IL-6R signaling for hematopoietic regulation.