The Effects of Tcf-1 Gene Silence on Marrow CD4⁺ T Cells from Aplastic Anemia Patients.

As T-cell special expression gene, T cell factor 1 (Tcf-1) has an HMG-BOX domain be cognized as a transcription factor. We have found from our previous studies that Tcf-1 mRNA expression level in bone marrow (BM) CD4⁺ T cells from aplastic anemia (AA) patients is markedly higher than that of normal people. It is presumed that up-expression of Tcf-1 gene can be closely related to abnormal functions of BM CD4⁺ T cells from AA patients. Therefore in the current study, we discussed the effects of Tcf-1 gene silence on the BM CD4⁺ T cells from AA patients. Three shRNA expression vectors psiRNA1, psiRNA2 and psiRNA3 were constructed with psiRNA-hH1neo G2 plasmid. They were respectively transfected into Jurkat cells in which there was rather high expression level of Tcf-1 gene, then Tcf-1 mRNA of Jurkat cells was assayed by semi-quantitative reverse-transcription polymerase chain reaction (RT-PCR). All three plasmid-derived siRNAs could effectively reduce the expression level of Tcf-1 mRNA in transfected Jurkat cells, but the plasmid-derived siRNA psiRNA2 was found to be the most effective inhibitor of Tcf-1 expression. Next, the selected psiRNA2 were transfected into the BM CD4⁺ T cells from six AA patients. It was found that the expression level of Tcf-1 mRNA in BM CD4⁺ T cells from these patients was reduced by 45.0%. At the same time, the expression levels of c-myc and CD44 mRNA in BM CD4⁺ T cells from these AA patients were also decreased to different extents, 47.7% and 53.7%, respectively. These results indicate that Tcf-1 gene can regulate downstream target genes such as c-myc and CD44 to participate in over-proliferation and activation of BM CD4⁺ T cells from AA patients. It is likely worthwhile to carry out the in-depth study against Tcf-1 in AA therapy.