title: Effects of Astragalus polysaccharide on the erythroid lineage and microarray analysis in K562 cells.
abstract: BACKGROUND
  Astragalus polysaccharide (APS), obtained from Astragalus membranaceus, displays a range of activities in many systems, including the promotion of immune responses, anti-inflammation, and the protection of vessels. It possesses potent pharmacological activity on differentiation to the erythroid lineage.
  
  
  OBJECTIVE
  To investigate the effects of APS on the erythroid differentiation and the mechanism of action by microarray analysis in K562 cells.
  
  
  METHODS
  Benzidine staining, semi-quantitative RT-PCR, Western blot and microarray methods were used to survey the effects of APS on inducing erythroid differentiation and the changes of gene expression profile in K562 cells.
  
  
  RESULTS
  Of the 13.2% positive cells detected by benzidine staining, the induction was the highest with 200 microg/ml APS on 72h. Ggamma-mRNA expression and fetal hemoglobin synthesis were significantly up-regulated. Microarray analysis showed that 31 genes were up-regulated and 108 genes were down-regulated. These differential expression genes generally regulate protein binding, cellular metabolic process, the cell proliferation, and transcriptional activator activity. The gamma-globin gene was up-regulated, the genes related with erythroid differentiation such as LMO2, Runx1 and GTF2I were up-regulated, while Bklf, Eklf, EPHB4 and Sp1 were down-regulated.
  
  
  CONCLUSIONS
  Our studies indicate that APS indicate potent activities on the erythroid differentiation by modulating genes of LMO2, Klf1, Klf3, Runx1, EphB4 and Sp1, increasing gamma-globin mRNA expression and fetal hemoglobin synthesis in K562 cells.
authors.affiliation: Department of Neonatology, Nanfang Hospital Affiliated Nanfang Medical University, 1838 Guang Zhou Da Dao North, Guangzhou 510515, Guangdong, PR China.
authors.forename: Min
authors.initials: M
authors.lastname: Yang
authors.forename: Xin-Hua
authors.initials: XH
authors.lastname: Qian
authors.forename: Dan-Hua
authors.initials: DH
authors.lastname: Zhao
authors.forename: Su-Zhen
authors.initials: SZ
authors.lastname: Fu
mesh_terms: D027885:Astragalus propinquus; D019070:Cell Lineage / Q000187:drug effects* / Q000502:physiology; D049109:Cell Proliferation / Q000187:drug effects; D041905:Erythroid Cells / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D006801:Humans; D020014:K562 Cells; D011134:Polysaccharides / Q000302:isolation & purification / Q000494:pharmacology*; D040081:Protein Array Analysis / Q000379:methods*
chemical_list: D011134:Polysaccharides