Background and Aims: In the interleukin-10-deficient (Il10-/-) mouse model of IBD, 10 quantitative trait loci (QTL) have been shown to be associated with colitis susceptibility by linkage analyses on experimental crosses of highly susceptible C3H/HeJBir (C3Bir)-Il10-/- and partially resistant C57BL/6J (B6)-Il10-/- mice. The strongest locus (C3Bir-derived cytokine deficiency-induced colitis susceptibility [Cdcs]1 on Chromosome [Chr] 3) controlled multiple colitogenic subphenotypes and contributed the vast majority to the phenotypic variance in cecum and colon. This was demonstrated by interval-specific Chr 3 congenic mice wherein defined regions of Cdcs1 from C3Bir or B6 were bred into the IL-10-deficient reciprocal background and altered the susceptible or resistant phenotype. Furthermore, this locus likely acts by inducing innate hypo- and adaptive hyperresponsiveness, associated with impaired NFB responses of macrophages. The aim of the present study was to dissect the complexity of Cdcs1 by further development and characterization of reciprocal Cdcs1 congenic strains and to identify potential candidate genes in the congenic interval. Material and Methods: In total, 15 reciprocal congenic strains were generated from Il10-/- mice of either C3H/HeJBir or C57BL/6J backgrounds by 10 cycles of backcrossing. Colitis activity was monitored by histological grading. Candidate genes were identified by fine mapping of congenic intervals, sequencing, microarray analysis and a high-throughput real-time RT-PCR approach using bone marrow-derived macrophages. Results: Within the originally identified Cdcs1-interval, three independent regions were detected that likely contain susceptibility-determining genetic factors (Cdcs1.1, Cdcs1.2, and Cdcs1.3). Combining results of candidate gene approaches revealed Fcgr1, Cnn3, Larp7, and Alpk1 as highly attractive candidate genes with polymorphisms in coding or regulatory regions and expression differences between susceptible and resistant mouse strains. Conclusions: Subcongenic analysis of the major susceptibility locus Cdcs1 on mouse chromosome 3 revealed a complex genetic structure. Candidate gene approaches revealed attractive genes within the identified regions with homologs that are located in human susceptibility regions for IBD.
Cdcs1 a major colitis susceptibility locus in mice; subcongenic analysis reveals genetic complexity.
Sex, Specimen part
View SamplesBased on studies in knockout mice, several inhibitory factors such as TGF-beta, IL-10, or CTLA-4 have been implicated as gate keepers of adaptive immune responses. Lack of these inhibitory molecules leads to massive inflammatory responses mainly mediated by activated T cells. In humans, the integration of these inhibitory signals for keeping T cells at a resting state is less well understood. To elucidate this regulatory network we assessed early genome-wide transcriptional changes during serum deprivation in human mature CD4+ T cells. The most striking observation was a "TGF-beta loss signature" defined by downregulation of many known TGF-beta target genes. Moreover, numerous novel TGF-beta target genes were identified that are under the suppressive control of TGF-beta. Expression of these genes was upregulated once TGF-beta signaling was lost during serum deprivation and again suppressed upon TGF-beta reconstitution. Constitutive TGF-beta signaling was corroborated by demonstrating phosphorylated SMAD2/3 in resting human CD4+ T cells in situ, which were dephosphorylated during serum deprivation and re-phosphorylated by minute amounts of TGF-beta. Loss of TGF-beta signaling was particularly important for T cell proliferation induced by low-level T cell receptor and costimulatory signals. We suggest TGF-beta to be the most prominent factor actively keeping human CD4+ T cells at a resting state.
Human resting CD4+ T cells are constitutively inhibited by TGF beta under steady-state conditions.
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View SamplesPurpose: CEBPA mutations are found as either biallelic (biCEBPA) or monoallelic (moCEBPA). We set out to explore whether the kind of CEBPA mutation is of prognostic relevance in cytogenetically normal AML (CN-AML).
Acute myeloid leukemia with biallelic CEBPA gene mutations and normal karyotype represents a distinct genetic entity associated with a favorable clinical outcome.
Specimen part
View SamplesPatients with cytogenetically normal acute myeloid leukemia (CN-AML) show heterogeneous treatment outcomes. We used gene expression profiling to develop a gene signature that predicts overall survival (OS) in CN-AML. Based on data from 163 patients treated in the German AMLCG 1999 trial and analyzed on oligonucleotide microarrays, we used supervised principal component analysis to identify 86 probe sets (representing 66 different genes) which correlated with OS, and defined a prognostic score based on this signature. When applied to an independent cohort of 79 CN-AML patients, this continuous score remained a significant predictor for OS (hazard ratio [HR], 1.85; P=0.002), EFS (HR, 1.73; P=0.001), and RFS (HR, 1.76; P=0.025). It kept its prognostic value in multivariate analyses adjusting for age, FLT3 ITD and NPM1 status. In a validation cohort of 64 CN-AML patients treated on CALGB study 9621, the score also predicted OS (HR, 4.11; P<0.001), EFS (HR, 2.90; P<0.001), and RFS (HR, 3.14, P<0.001) and retained its significance in a multivariate model for OS. In summary, we present a novel gene expression signature that offers additional prognostic information for patients with CN-AML.
An 86-probe-set gene-expression signature predicts survival in cytogenetically normal acute myeloid leukemia.
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