Proanthocyanidin A1 promotes the production of platelets to ameliorate chemotherapy-induced thrombocytopenia through activating JAK2/STAT3 pathway

Chemotherapy-induced thrombocytopenia (CIT) is a severe adverse drug reaction, and the main reason for CIT is the destruction of megakaryocytes (MKs, precursor cells of platelet) in bone marrow by chemotherapy. Peanut skin, the seed coat of Arachis hypogaea L., is a traditional Chinese medicine commonly used to treat thrombocytopenia. However, its active compounds and the mechanisms remain unclear.This study aims to clarify the active compounds of peanut skin to exhibit thrombogenic effects against CIT and their underlying mechanisms in vitro and in vivo.The bioassay-guided isolation based on the proliferation of MKs was used to explore the possible platelet-enhancing ingredients in peanut skin. HSCCC technique coupled with preparative HPLC was used to separate the active compounds. Dami cells and carboplatin-treated mice model were used to evaluate the thrombogenic effects of PS-1. Network pharmacology, molecular docking, dynamics simulation studies, kinase activity, surface plasmon resonance (SPR), cellular thermal shift assay (CETSA), isothermal dose-response fingerprint (ITDRFCETSA) and western blot analysis were performed to investigate the mechanisms of PS-1.Proanthocyanidin A1 (PS-1) and its stereoisomers (PS-2-4) were demonstrated to promote the proliferation of MKs (Dami cells), especially PS-1 (EC50 = 8.58 μM). Further studies demonstrated that PS-1 could induce the differentiation of Dami cells in dose/time-dependent manner. Biological target analysis showed that PS-1 directly bound to JAK2 (KD = 2.06 μM) to exert potent activating effect (EC50 = 0.66 μM). Oral administration of PS-1 (25 or 50 mg/kg) significantly improved CIT, but this effect was confirmed to be inhibited by JAK2 inhibitor AG490, indicating that PS-1 exerted its efficacy through JAK2 in vivo.Proanthocyanins (PS-1-4) derived from peanut skin were first clarified as platelet-enhancing ingredients to improve CIT. The underlying mechanism of PS-1 was proved to promote the proliferation and differentiation of MKs via JAK2/STAT3 pathway both in vitro and in vivo.