Genomic expression profiling of TNFalpha treated BDC2.5 diabetogenic CD4+ T Cells

Tumor necrosis factor alpha (TNFalpha) plays an important role in immune regulation, inflammation, and autoimmunity. Chronic TNFalpha exposure has been shown to down-modulate T cell responses. In a mouse T cell hybridoma model, TNFalpha attenuated T cell receptor (TCR) signaling. We have confirmed that chronic TNFalpha and anti-TNFalpha exposure suppressed and increased T cell responses in BDC2.5 CD4+ T cells, respectively. The goal of this study is to analyze global transcriptional alterations resulting from TNFalpha treatment on TCR signaling pathways using cDNA microarrays. We found that genes involved in functional categories including T cell signaling, cell cycle, proliferation, ubiquitination, cytokine synthesis, calcium signaling, and apoptosis were modulated. Genes such as ubiquitin family genes, cytokine inducible SH2-containing genes, cyclin-dependent kinase inhibitors p21, p57, calmodulin family genes (calmodulin -V1, -V2, and ?V3) and calcium channel voltage- dependent, N type alpha1B subunit (CaV2.2) were induced by TNFalpha, while Vav2, Rho GTPase activating protein, calcium channel voltage dependent, L type alpha 1C subunit (CaV1.2), interleukin-1 (IL) receptor-associated kinase 1, and -V2 (IRAK-1and -2) and IL enhancer binding factor 3 were reduced by TNFalpha. Genes such as CaV1.2 and proliferating cell nuclear antigen, repressed by TNFalpha, were induced by anti-TNF treatment. Further, we showed that chronic TNFalpha exposure impaired NF-kappaB and AP-1 transactivation activity, leading to T cell unresponsiveness. Thus, our results present a detailed picture of transcriptional programs affected by chronic TNFalpha exposure, and provide candidate target genes, which may function to mediate TNFalpha induced T cell unresponsiveness. Set of arrays that are part of repeated experiments Keywords: Biological Replicate The experiments addressed the effect of TNF exposure. 8-12-week-old NOD.BDC2.5 transgenic mice were injected i.p. with PBS or 3 ug murine TNFalpha; on alternate days for three weeks. At day 24 of treatment, suspensions of LNs and/or splenocytes were stimulated with the indicated concentration of the mimotope (1047-7 peptide (YVAPVWVRME)) at a density of 7-8 x 106 cells/ml, in a final volume of 1 ml in 24-well plates. After prolonged in vitro culture, cells were harvested 12 hrs post transplantation. CD4+ T cells were purified by labeling of monoclonal Abs of surface markers, Vbeta4-FITC and CD4-PE and enriched by Magnetic beads selection followed by FACS sorting. The purity of CD4+ T cells ranged from 95% to 99% depending on individual CD4 T cells preparation. The data in column represents six independent repeated experiments with half of the slides being reverse replicates. We compared RNA from PBE treated group with TNF treated group without including reference RNA.