Abstract: Objective To investigate the effect of simulated microgravity on erythroid differentiation of K562 cells and explore
the possible mechanism. Methods The fourth generation rotating cell culture system was used to generate the simulated
microgravity environment. Benzidine staining was used to evaluate the cell inhibition rate, and real-time quantitative PCR
(qRT-PCR) was used to detect GATA-1, GATA-2, Ets-1, F-actin, β-Tubulin and vimentin mRNA expressions. The changes of
cytoskeleton were observed by fluorescence microscopy, and Western blotting was employed to assay F-actin, β-tubulin and
vimentin protein expression levels. Results Benzidine staining showed that simulated microgravity inhibited erythroid
differentiation of K562 cells. K562 cells treated with Hemin presented with increased mRNA expression of GATA-1 and
reduced GATA-2 and Ets-1 mRNA expressions. Simulated microgravity treatment of the cells resulted in down-regulated
GATA-1, F-actin, β-tubulin and vimentin mRNA expressions and up-regulated mRNA expressions of GATA-2 and Ets-1, and
reduced F-actin, β-tubulin and vimentin protein expressions. Exposure to simulated microgravity caused decreased
fluorescence intensities of cytoskeletal filament F-actin, β-tubulin and vimentin in the cells. Conclusion Simulated
microgravity inhibits erythroid differentiation of K562 cells possibly by causing cytoskeleton damages to result in
down-regulation of GATA-1 and up-regulation of GATA-2 and Ets-1 expressions.