Project description:Cellular binary fate decisions require the progeny to silence genes associated with the alternative fate. The major subsets of alpha:beta T cells have been extensively studied as a model system for fate decisions. While the transcription factor RUNX3 is required for the initiation of Cd4 silencing in CD8 T cell progenitors, it is not required to maintain the silencing of Cd4 and other helper T lineage genes. The other runt domain containing protein, RUNX1, silences Cd4 in an earlier T cell progenitor, but this silencing is reversed whereas the gene silencing after RUNX3 expression is not reverse. Therefore, we hypothesized that RUNX3 and not RUNX1 recruits other factors that maintains the silencing of helper T lineage genes in CD8 T cells. To this end, we performed a proteomics screen of RUNX1 and RUNX3 to determine candidate silencing factors.
Project description:Myeloid-derived suppressor cells (MDSC) are a major barrier to anticancer responses. Although much is known about how MDSC promote tumor progression, little is known about how they develop. We hypothesized that MDSC develop as a consequence of tumor-induced downregulation of interferon regulatory factor-8 (IRF-8), a key myeloid developmental transcription factor. We showed that: 1) IRF8-deficiency in mice generated myeloid populations highly homologous to tumor-induced MDSC; 2) IRF-8 overexpression in mice reduced MDSC accumulation and retarded tumor growth; 3) MDSC-inducing factors, G-CSF or GM-CSF, facilitated IRF-8 downregulation via STAT3- or STAT5-dependent pathways, respectively; and 4) IRF-8 levels in MDSC-like subsets of breast cancer patients were depressed compared to healthy donors. Altogether, our data implicate IRF-8 as a novel MDSC-dependent transcription factor. Splenic CD11b+Gr-1high cell populations from tumor-bearing mice, IRF8 knockout mice or non-tumor-bearing control mice were purified in two independent experiments by flow cytometry (> 97% purity) and subjected to whole genome expression profiling using Illumina microarrays.
Project description:Myeloid derived Suppressor cells (MDSC) are heterogenous popluation of cells consists of two major subsets namely the monocytic Gr-1dull/int. and granulocytic (Gr-1high). These distinct two subsets use different mechanism to inhibit T cell response. In addition, how the function of these subsets is regulated is not known yet. The Gr-1dull/int. MDSC are suppressing T cells through IFNg dependent nitric oxide dependent manner. However, the exact suppressive mechanism of Gr-1high MDSC is not clear. Here we studied the role of a cytokine IFNg on the suppressive function of Gr-1high MDSC by comparing the gene expression of Gr-1high cells cultured alone versus those cultured with T cells which donot produce IFNgamma. CD11b+Gr-1high cells were purified from the splenocyte of CT-26 colon tumor bearing mice. The purified CD11b+Gr-1high MDSCs were cultured with IFNg-/- antigen specific T cells and re- sorted after 48h and RNA was extracted and gene expression was analyzed using topic-defined PIQORTM Immunology Microarrays.
Project description:We collected whole genome testis expression data from hybrid zone mice. We integrated GWAS mapping of testis expression traits and low testis weight to gain insight into the genetic basis of hybrid male sterility.
