DNA microarray gene expression profile of T cells with the splice variants of TCRζ mRNA observed in systemic lupus erythematosus

We have reported that the TCRζ mRNA with alternatively spliced 3′ UTR (ζ mRNA/as-3′-untranslated region (UTR)) and ζ mRNA lacking exon 7 (ζ mRNA/exon 7-) observed in systemic lupus erythematosus patient T cells can lead to down-regulation of both ζ and TCR/CD3 complexes. To determine whether these T cells expressing decreased ζ exhibit differential transcription patterns, we transfected retrovirus vectors containing wild-type ζ cDNA, ζ cDNA/as-3′ UTR, and ζ cDNA/exon 7- into murine T cell hybridoma MA5.8 cells which lack ζ expression to construct the MA5.8 mutants WT, AS3′ UTR, and EX7-, respectively. FACS analyses demonstrated reduced cell surface expression of ζ 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-β2, 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 ζ and TCR/CD3 complexes were down-regulated may help to better understand the pathogenesis of systemic lupus erythematosus.