MEL细胞系中铁对转铁蛋白受体mRNA和铁螯合酶mRNA表达的调节

Expression of transferrin receptor and ferrochelatase mRNAs in MEL cells

目的通过对ＭＥＬ细胞在二甲基亚砜（ＤＭＳＯ）诱导分化前后和不同的铁状态，观察转铁蛋白受体（ＴｆＲ）ｍＲＮＡ和铁螯合酶ｍＲＮＡ含量的变化。方法ＭＥＬ细胞体外培养，加ＤＭＳＯ向红系诱导分化，同时以未诱导细胞为对照，应用Ｎｏｒｔｈｅｒｎｂｌｏｔ检测ＴｆＲｍＲＮＡ和铁螯合酶ｍＲＮＡ含量，观察加入转铁蛋白、去铁胺或抗ＴｆＲ单抗和Ｅｐｏ后的作用。结果和结论①未诱导的ＭＥＬ细胞，随着细胞的增殖，ＴｆＲｍＲＮＡ含量增加；诱导的ＭＥＬ细胞，虽然随着细胞分化成熟而丧失增殖能力，但当存在血红素合成时，ＴｆＲｍＲＮＡ含量也增高，且增高幅度较非诱导组高。②未诱导的ＭＥＬ细胞，降低细胞内铁含量（培养液中加入去铁胺或抗ＴｆＲ单抗），可刺激ＴｆＲｍＲＮＡ表达，增加细胞内铁含量（培养液中加入转铁蛋白），则抑制ＴｆＲｍＲＮＡ的表达；诱导的ＭＥＬ细胞，相同条件的铁状态时，细胞内ＴｆＲｍＲＮＡ水平发生类似的改变，但变化的程度较小。③当培养液中加入Ｅｐｏ刺激红系细胞分化时，促进ＴｆＲｍＲＮＡ的表达。上述结果提示，在红系细胞，ＴｆＲｍＲＮＡ的表达除受细胞内铁调节外，也受细胞内血红素合成的影响。④未诱导的ＭＥＬ细胞，虽然细胞增生旺盛，但铁螯合酶ｍＲＮＡ?

Objective To investigate the changes of transferrin receptor (TfR) mRNA and ferrochelatase mRNA levels under different iron status of DMSO induced or non induced MEL cells. Methods MEL cells were induced with 1.5% DMSO. TfR mRNA and ferrochelatase mRNA were assayed by Northern blot after adding transferrin, deferrioxamine, anti TfR monoclonal antibody (McAb) or Epo, respectively. Results and conclusion ①TfR mRNA level increased with cell proliferation in non induced MEL cells, while in the induced MEL cells, although the proliferating capacity was losing with cell maturation, TfR mRNA level increased with hemoglobin synthesis and its amplitude was higher than that in non induced cells. ②In both non induced and induced MEL cells, TfR mRNA levels increased when intracellular iron level decreased; and vice versa. ③Stimulation of erythropoiesis by Epo increased the expression of TfR mRNA, indicating that its expression in erythroid cells was regulated by the level of intracellular iron and the synthesis of heme. ④The expression of ferrochelatase mRNA had no change in non induced MEL cells, but increased significantly in induced MEL cells. ⑤The level of intracellular iron in non induced and induced MEL cells had less effects on the expression of ferrochelatase mRNA.