Angelica sinensis polysaccharides promote extramedullary stress erythropoiesis via ameliorating splenic glycolysis and EPO/STAT5 signaling-regulated macrophages

Abstract

Background Extrinsic molecular mechanisms that regulate extramedullary stress erythropoiesis are still poorly understood, and the exploration of potential protective medication is needed. Materials and methods Peripheral blood parameters and BFU-E colony enumeration were measured. IHC staining was conducted to detect the proliferation of splenocytes and splenic F4/80 macrophages. The expression of β-catenin protein in RAW264.7 macrophages was assessed using immunofluorescence. The cell cycle of mouse spleen c-kit+ cells was analyzed by flow cytometry assay. Detection of Ccl2, Hk2, and Pgk1 mRNA expression by RT-qPCR. Cyclin D1 protein expression was assessed using Western blotting. IL-1 and EPO levels were determined by ELISA assay. Results In the 5-FU pre-administrated mouse, ASP rescued peripheral blood parameters such as RBC counts, HGB, HCT and MCH, and the BFU-E colony enumeration in the bone marrow. Meanwhile, ASP increased cellular proliferation in the splenic red pulp and cyclin D1 expression, ASP increased macrophage chemokine Ccl2 genetic expression and the number of F4/80 macrophages in the spleen and splenic BFU-E enumeration. Furthermore, ASP facilitated glycolytic genes including Hk2, Pgk1, Pkm, Pdk1 and Ldha via PI3K/Akt/HIF2α signaling in the spleen. Subsequently, ASP declined pro-proinflammatory factor IL-1β, whereas upregulating erythroid proliferation-associated genes Gdf15, Bmp4, Wnt2b, and Wnt8a. Moreover, ASP facilitated EPO/STAT5 signaling in splenic macrophages to enhance erythroid lineage Gata2, Gata1 genetic expression. Also, ASP facilitated erythroid differentiation via macrophage-mediated EpoR/STAT5 signaling. Conclusions ASP facilitate extramedullary stress erythropoiesis that suggest it might be a promising strategy for stress anemia treatment.