STIM1 controls T cell mediated immune regulation and inflammation in chronic infection. Mus musculus

Influence of STIM1 on the transcriptome of CD4+ T cell subsets STIM1 is critical for the regulation of the intracellular Ca2+ homeostasis in CD4+ T cell. Loss of function mutations in STIM1 in patients result in severe immuno deficiency and recurrent infections. Using conditional knock out mice for STIM1, we investigated the role of STIM1 in T cells during chronic infections by in-vivo and in-vitro experiments. We found that STIM1 is required for T cell-mediated immunity to chronic infection with Mycobacterium tuberculosis (Mtb) as STIM1-deficient mice succumb to infection faster than littermate controls, have increased mycobacterial burdens and severe pulmonary infiltration with myeloid and lymphoid cells .Using the Affymetrix Mouse Exon 1.0 platform, we analyzed the influence of STIM1 expression on the transcriptom of CD4+T cells in-vitro. We found that STIM1 is required for the regulation of apoptosis related genes after TCR stimulation as well as for the induction of a transcriptonal program that polarizes naive CD4+ T cells into inducible CD4+ T regulatory cells (iTreg). Together with our in-vivo findings, these experiments reveal that STIM1 is essential for immune regulation to prevent an injurious inflammatory response during chronic infection. Overall design: For microarry analysis, CD4+ T cells from WT or Stim1CD4 mice were isolated and stimulated with anti- CD3 and anti-CD28 antibodies for 48h in the presence or absence of TGFβ. Total RNA was isolated using the RNeasy micro RNA isolation kit (Quiagen). Biotin-labeled amplified aRNA was prepared and hybridized to 1.0 Exon expression chips (Affymetrix) according to the manufacturer’s protocols. The values in the sample data tables were derived from the Expression Console Software (Affymetrix) by performing a gene-level normalization and signal summarization on the raw CEL files (gene-level analysis). Obtained CHP files were subsequently analyzed and visualized using TAC software (Affymetrix) and IPA pathway analysis software (Qiagen). 3 age matched mice per group and condition were used, no technical replicates were used.