1. Molecular alterations in the TCR signaling pathway in patients with aplastic anemia.
- Author
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Li B, Guo L, Zhang Y, Xiao Y, Wu M, Zhou L, Chen S, Yang L, Lu X, and Li Y
- Subjects
- 3' Untranslated Regions genetics, Adaptor Proteins, Signal Transducing genetics, Adolescent, Adult, Aged, Aged, 80 and over, Alternative Splicing, Anemia, Aplastic pathology, CD28 Antigens genetics, CD3 Complex genetics, CTLA-4 Antigen genetics, Child, Female, Humans, Male, Middle Aged, Polymorphism, Single Nucleotide, Proto-Oncogene Proteins c-cbl genetics, Reverse Transcriptase Polymerase Chain Reaction, Young Adult, Anemia, Aplastic genetics, Gene Expression, Receptors, Antigen, T-Cell genetics, Signal Transduction genetics
- Abstract
Background: A previous study has demonstrated a significantly increased CD3ζ gene expression level in aplastic anemia (AA). However, the mechanism underlying the upregulated CD3ζ mRNA expression level and that of T cell activation signaling molecules in AA patients remains unclear. Thus, we investigated the expression levels of the CD3ζ, CD28, CTLA-4, and Cbl-b genes, the SNP rs231775 in the CTLA-4 gene, and the distribution of the CD3ζ 3'-UTR splice variant in AA patients., Methods: CD3ζ 3'-UTR splice variants were identified in peripheral blood mononuclear cells (PBMCs) from 48 healthy individuals and 67 patients with AA [37 cases of severe aplastic anemia (SAA) and 30 cases of non-sever aplastic anemia (NSAA)] by RT-PCR. CD3ζ, CD28, CTLA-4, and Cbl-b gene expression was analyzed by real-time quantitative PCR. The SNP rs231775 in CTLA-4 gene was analyzed by PCR-RFLP., Results: CD3ζ and CD28 expression was significantly higher, while CTLA-4 and Cbl-b expression was significantly lower in AA patients compared with healthy individuals. Significantly higher CD3ζ expression was found in the NSAA subgroup compared with the SAA subgroup. 64 % of the AA samples had the same genotype (WT(+)AS(+)CD3ζ 3'-UTR); 22 % of the AA patients had a WT(+)AS(-)CD3ζ 3'-UTR genotype, and 14 % of the AA patients had a WT(-)AS(+)CD3ζ 3'-UTR genotype. The CD3ζ expression level of WT(-)AS(+) subgroup was the highest in the SAA patients. A significantly higher frequency of the GG genotype (mutant type, homozygous) of SNP rs231775 in CTLA-4 gene was found in the AA patients. Positive correlation between the CTLA-4 and Cbl-b gene expression levels was found in healthy individuals with the AA and AG genotypes, but not in the AA patients., Conclusions: This is the first study analyzing the expression characteristics of the CD28, CTLA-4, and Cbl-b genes in AA. Our results suggest that aberrant T cell activation may be related to the first and second signals of T cell activation in AA. The GG genotype of SNP rs231775 in CTLA-4 gene might be associated with AA risk in the Chinese population. The characteristics of CD3ζ 3'-UTR alternative splicing may be an index for evaluating the T cell activation status in AA patients, particularly in SAA patients.
- Published
- 2016
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