Wilms tumor (nephroblastoma) is a pediatric kidney tumor that arises from renal progenitor cells. Since the blastemal type is associated with adverse prognosis, we characterized such Wilms tumors by exome and transcriptome analysis. We detected novel, recurrent somatic mutations affecting the SIX1/2 SALL1 pathway implicated in kidney development, the DROSHA/DGCR8 microprocessor genes as well as alterations in MYCN and TP53, the latter being strongly associated with dismal outcome. The DROSHA mutations impair the RNase III domains, while DGCR8 exhibits stereotypic E518K mutations in the RNA binding domain - both may skew miRNA representation. SIX1 and SIX2 mutations affect a single hotspot (Q177R) in the homeodomain indicative of a dominant effect. In larger cohorts, these mutations cluster in blastemal and chemotherapy-induced regressive tumors that likely derive from blastemal cells and these are characterized by generally higher SIX1/2 expression. These findings broaden the spectrum of human cancer genes and may open new avenues for stratification and therapeutic leads for Wilms tumors.
Mutations in the SIX1/2 pathway and the DROSHA/DGCR8 miRNA microprocessor complex underlie high-risk blastemal type Wilms tumors.
Sex
View SamplesAnalysis of the expression profile of adult mice heterozygous for Pitx2 isoform C.
PITX2c is expressed in the adult left atrium, and reducing Pitx2c expression promotes atrial fibrillation inducibility and complex changes in gene expression.
Age, Specimen part
View SamplesThis experiment was specifically designed to measure neural targets of Shh signaling, we sought to profile the genes upregulated by Hh signaling in the ventral neural tube to obtain a valid dataset. To obtain ventral-specific markers, we generated retinoic acid-treated EBs grown in the presence or absence of HH-Ag. We did not observe induction of ventral Hh markers in RA-treated constitutive Gli1FLAG EBs and used these for the control, baseline set. The presence of FoxA2, Nkx2.9 and Nkx6.1 amongst the top 10 genes based on expression levels suggests that profiling significantly enriches for Hh-dependent cell types. As expected, the benchmark standard Gli1 was not up-regulated in our array, since it is constitutively expressed in the control as well.
Genomic characterization of Gli-activator targets in sonic hedgehog-mediated neural patterning.
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View SamplesOBJECTIVE: To characterize the hormonal milieu and adipose gene expression in response to catch-up growth (CUG), a growth pattern associated with obesity and diabetes risk, in a mouse model of low birth weight (LBW). RESEARCH DESIGN AND METHODS: ICR mice were food restricted by 50% from gestational days 12.5-18.5, reducing offspring birth weight by 25%. During the suckling period, dams were either fed ad libitum, permitting CUG in offspring, or food restricted, preventing CUG. Offspring were killed at age 3 weeks, and gonadal fat was removed for RNA extraction, array analysis, RT-PCR, and evaluation of cell size and number. Serum insulin, thyroxine (T4), corticosterone, and adipokines were measured.
Accelerated postnatal growth increases lipogenic gene expression and adipocyte size in low-birth weight mice.
Sex, Age, Specimen part
View SamplesInsulin resistance in skeletal muscle is a key phenotype associated with type 2 diabetes (T2D) and is even present in offspring of diabetic parents. However, molecular mediators of insulin resistance remain unclear. We find that the top-ranking gene set in expression analysis of muscle from humans with T2D and normoglycemic insulin resistant subjects with parental family history (FH+) of T2D is increased expression of actin cytoskeleton genes regulated by serum response factor (SRF) and its coactivator MKL1. Furthermore, the SRF activator STARS is upregulated in FH+ and T2D and inversely correlated with insulin sensitivity. These patterns are recapitulated in insulin resistant mice, and linked to alterations in two other regulators of this pathway: reduced G-actin and increased nuclear localization of MKL1. Both genetic and pharmacologic manipulation of STARS/MKL1/SRF pathway significantly alter insulin action: 1) Overexpression of MKL1 or reduction in G-actin decreased insulin-stimulated Akt phosphorylation; 2) reduced STARS expression increased insulin signalling and glucose uptake, and 3) SRF inhibition by CCG-1423 reduced nuclear MKL1, improved glucose uptake, and improved glucose tolerance in insulin resistant mice in vivo. Thus, SRF pathway alterations are a signature of insulin resistance which may also contribute to T2D pathogenesis and be a novel therapeutic target.
Increased SRF transcriptional activity in human and mouse skeletal muscle is a signature of insulin resistance.
Sex, Age, Specimen part
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