LAUSR

The Th2 cytokine IL-4 triggers a signaling cascade which activates transcription by STAT6. The goals of the present study are to define the transcriptomic response of mouse spleen B cells (mSBC) to IL-4 used as single stimulus, its specificity compared to human peripheral blood B cells (hPBBC) and to mouse spleen T cells (mSTC), and the pathways affected. Oligonucleotide-based microarrays were performed using two references, the untreated sample and the cells cultured without IL-4, an experimental design which reduces the potential confounding effect of cellular stress during culture. Specificity was addressed by comparing the response of mSBC and our previously published study on hPBBC, of similar design, and a study by other authors on mSTC. We detected an mSBC-specific response (including novel genes, e.g., Sertad4, Lifr, Pmepa1, Epcam, Tbxas1; and common genes, e.g., Usp2, Cst7, Grtp1, and Casp6), an hPBBC-specific response (e.g., CCL17, MTCL1, GCSAM, HOMER2, IL2RA), and a common mSBC/hPBBC response (e.g., CISH, NFIL3, SOCS1, VDR, CDH1). In contrast, the mSBC and mSTC responses were largely divergent. Gene set enrichment analysis (GSEA) was applied for the first time to identify the pathways affected. Both in mSBC and hPBBC, IL-4 activated Myc, the transcriptional machinery itself, cell cycle, mitochondria and respiratory chain, ribosome, proteasome and antigen presentation, and Wnt signaling, and inhibited GPCR signaling. However, significant differences were found in histone demethylation, Nod signaling, and Rho signaling, which were downregulated in mSBC, and in chromatin condensation, which was downregulated in hPBBC. These findings may have therapeutic implications for the treatment of allergic diseases and parasitic infections.