Interferon-γ suppresses activin A/NF-E2 induction of erythroid gene expression through the NF-κB/c-Jun pathway.

Interferon (IFN)-γ is a proinflammatory cytokine that is linked to erythropoiesis inhibition and may contribute to anemia. However, the mechanism of IFN-γ-inhibited erythropoiesis is unknown. Activin A, a member of the transforming growth factor (TGF)-β superfamily, induces the erythropoiesis of hematopoietic progenitor cells.

Basic fibroblast growth factor inhibits p38-mediated cell differentiation and growth inhibition by activin A but not by histone deacetylase inhibitors in CML cells.

The p38 mitogen-activated protein kinase (p38) is involved in multiple cellular functions such as cell proliferation and differentiation. Previously, we found that activin A mediated hemoglobin synthesis and cell growth inhibition through p38, whereas, basic fibroblast growth factor (bFGF) inactivated p38 to antagonize the activin A effects. In this study, we selected three structurally different histone deacetylase (HDAC) inhibitors, apicidin, MS275, and sodium butyrate that activate p38, to probe the signal pathway from activin A to p38 in chronic myeloid leukemia (CML)-derived K562 cells.

Activin A induces erythroid gene expressions and inhibits mitogenic cytokine-mediated K562 colony formation by activating p38 MAPK.

Activin A, a member of the transforming growth factor (TGF)-beta superfamily, is involved in the regulation of erythroid differentiation. Previous studies have shown that activin A inhibited the colony-forming activity of mouse Friend erythroleukemia cells, however, the mechanism remains unknown. First, we show herein that activin A induced the expression and activated the promoters of alpha-globin and zeta-globin in K562 cells, confirming that activin A induces erythroid differentiation in K562 cells.