Publications (3)14.39 Total impact
- [Show abstract] [Hide abstract] ABSTRACT: Systemic lupus erythematosus (SLE) is a systemic autoimmune disease of unknown etiology. Tyrosine phosphorylation and protein expression of the T-cell receptor zeta chain (zeta) have been reported to be significantly decreased in SLE T cells. In addition, zeta mRNA with alternatively spliced 3' untranslated region (zetamRNA/as-3'UTR) is detected predominantly in SLE T cells, and aberrant zeta mRNA accompanied by the mutations in the open reading frame including zeta mRNA lacking exon7 (zetamRNA/exon7-) is observed in SLE T cells. These zeta mRNA splice variant forms exhibit a reduction in the expression of TCR/CD3 complex and zeta protein on their cell surface due to the instability of zeta mRNA splice variant forms as well as the reduction in interleukin (IL)-2 production after stimulating with anti-CD3 antibody. Data from cDNA microarray showed that 36 genes encoding cytokines and chemokines, including IL-2, IL-15, IL-18, and TGF-beta2, were down-regulated in the MA5.8 cells transfected with the zeta mRNA splice variant forms. Another 16 genes were up-regulated and included genes associated with membranous proteins and cell damage granules, including the genes encoding poliovirus-receptor-related 2, syndecan-1, and granzyme A.
- [Show abstract] [Hide abstract] ABSTRACT: We have reported that the TCRzeta mRNA with alternatively spliced 3' UTR (zeta mRNA/as-3'-untranslated region (UTR)) and zeta mRNA lacking exon 7 (zeta mRNA/exon 7-) observed in systemic lupus erythematosus patient T cells can lead to down-regulation of both zeta and TCR/CD3 complexes. To determine whether these T cells expressing decreased zeta exhibit differential transcription patterns, we transfected retrovirus vectors containing wild-type zeta cDNA, zeta cDNA/as-3' UTR, and zeta cDNA/exon 7- into murine T cell hybridoma MA5.8 cells which lack zeta expression to construct the MA5.8 mutants WT, AS3' UTR, and EX7-, respectively. FACS analyses demonstrated reduced cell surface expression of zeta and TCR/CD3 complexes on the AS3' UTR mutant and the EX7- mutant in comparison to that on the WT mutant. Total RNA was collected after stimulating the MA5.8 mutants with anti-CD3 Ab. Reverse-transcribed cDNA was applied to the mouse cDNA microarray containing 8691 genes, and the results were confirmed by real-time PCR. The results showed that 36 genes encoding cytokines and chemokines, including IL-2, IL-15, IL-18, and TGF-beta2, were down-regulated in both the AS3' UTR mutant and the EX7- mutant. Another 16 genes were up-regulated in both, and included genes associated with membranous proteins and cell damage granules, including the genes encoding poliovirus receptor-related 2, syndecan-1, and granzyme A. Increased protein expression of these genes was confirmed by Western blot and FACS analyses. Identification of these responsive genes in T cells in which the zeta and TCR/CD3 complexes were down-regulated may help to better understand the pathogenesis of systemic lupus erythematosus.
- [Show abstract] [Hide abstract] ABSTRACT: The integrin alpha(E)beta(7) is expressed on intestinal intraepithelial T lymphocytes and CD8(+) T lymphocytes in inflammatory lesions near epithelial cells. Adhesion between alpha(E)beta(7)(+) T and epithelial cells is mediated by the adhesive interaction of alpha(E)beta(7) and E-cadherin; this interaction plays a key role in the damage of target epithelia. To explore the structure-function relationship of the heterophilic adhesive interaction between E-cadherin and alpha(E)beta(7), we performed cell aggregation assays using L cells transfected with an extracellular domain-deletion mutant of E-cadherin. In homophilic adhesion assays, L cells transfected with wild-type or a domain 5-deficient mutant formed aggregates, whereas transfectants with domain 1-, 2-, 3-, or 4-deficient mutants did not. These results indicate that not only domain 1, but domains 2, 3, and 4 are involved in homophilic adhesion. When alpha(E)beta(7)(+) K562 cells were incubated with L cells expressing the wild type, 23% of the resulting cell aggregates consisted of alpha(E)beta(7)(+) K562 cells. In contrast, the binding of alpha(E)beta(7)(+) K562 cells to L cells expressing a domain 5-deficient mutant was significantly decreased, with alpha(E)beta(7)(+) K562 cells accounting for only 4% of the cell aggregates, while homophilic adhesion was completely preserved. These results suggest that domain 5 is involved in heterophilic adhesion with alpha(E)beta(7), but not in homophilic adhesion, leading to the hypothesis that the fifth domain of E-cadherin may play a critical role in the regulation of heterophilic adhesion to alpha(E)beta(7) and may be a potential target for treatments altering the adhesion of alpha(E)beta(7)(+) T cells to epithelial cells in inflammatory epithelial diseases.
Saitama Medical University
Саитама, Saitama, Japan
- Research Center for Genomic Medicine