Gene network of erythropoietic cells
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Specimen part
View SamplesIn order to elucidate the molecular mechanism giving rise to the rare In(Lu) type of Lu(a-b-) blood group phenotype we compared the transcriptome of normal and In(Lu) erythroblasts at different stages of maturation. Many erythroid-specific genes had reduced transcript levels suggesting the phenotype resulted from a transcription factor abnormality. A search for mutations in erythroid transcription factors revealed mutations in the promoter or coding sequence of EKLF in 21 of 24 individuals with the In(Lu) phenotype. In all cases the mutant EKLF allele occurred in the presence of a normal EKLF allele. Individuals with the In(Lu) phenotype have no reported pathology indicating that one functional EKLF allele is sufficient to sustain human erythropoiesis. These data provide the first description of inactivating mutations in human EKLF and the first demonstration of a blood group phenotype resulting from mutations in a transcription factor.
Mutations in EKLF/KLF1 form the molecular basis of the rare blood group In(Lu) phenotype.
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View SamplesWe used high density oligonucleotide arrays to identify molecular correlates of genetically and clinically distinct subgroups of B-cell chronic lymphocytic leukemia (B-CLL). Gene expression profiling was used to profile the five most frequent genomic aberrations, namely deletions affecting chromosome bands 13q14, 11q22-q23, 17p13 and 6q21, and gains of genomic material affecting chromosome band 12q13. A strikingly high degree of correlation between loss or gain of genomic material and the amount of transcripts from the affected regions leads to the hypothesis of gene dosage as a significant pathogenic factor. Furthermore, the influence of the immunoglobulin variable heavy chain (VH) mutation status was determined. A clear distinction in the expression profiles of unmutated and mutated VH samples exists, which can be discovered using unsupervised learning methods. However, when samples were separated by gender, this separation could only be detected in samples from male patients.
Microarray gene expression profiling of B-cell chronic lymphocytic leukemia subgroups defined by genomic aberrations and VH mutation status.
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View SamplesThe mitogen-activated protein kinase (MAPK) p38alpha controls inflammatory responses and cell proliferation. Using mice carrying conditional p38alpha alleles, we investigated its function in postnatal development and tumorigenesis. When p38alpha is specifically deleted in the mouse embryo, fetuses develop to term but die shortly after birth, likely due to lung dysfunction. Fetal hematopoietic cells and embryonic fibroblasts deficient in p38alpha display increased proliferation, resulting from sustained activation of the c-Jun N-terminal kinase (JNK)/c-Jun pathway. Importantly, in chemical-induced liver cancer development, mice with liver-specific deletion of p38alpha show enhanced hepatocyte proliferation and tumor development that also correlates with JNK/c-Jun upregulation. Furthermore, increased proliferation of p38alpha-deficient hepatocytes and tumor cells is suppressed by inactivation of JNK or c-Jun. These results reveal a novel mechanism whereby p38alpha negatively regulates cell proliferation through antagonizing the JNK/c-Jun pathway in multiple cell types and in liver cancer development.
p38alpha suppresses normal and cancer cell proliferation by antagonizing the JNK-c-Jun pathway.
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View SamplesThe non-coding Xist RNA triggers silencing of one of the two female X chromosomes during X inactivation in mammals. Gene silencing by Xist is restricted to special developmental contexts found in cells of the early embryo and specific hematopoietic precursors. The absence of critical silencing factors might explain why Xist cannot silence outside these contexts. Here, we show that Xist can also initiate silencing in a lymphoma model. Using the tumor context we identify the special AT rich binding protein SATB1 as an essential silencing factor. We show that loss of SATB1 in tumor cells abrogates the silencing function of Xist. In normal female lymphocytes Xist localizes along SATB1 filaments and, importantly, forced Xist expression can relocalize SATB1 into the Xist cluster. This reciprocal influence on localization suggests a molecular interaction between Xist and SATB1. SATB1 and its close homologue SATB2 are expressed during the initiation window for X inactivation in embryonic stem cells and are recruited to surround the Xist cluster. Furthermore, ectopic expression SATB1 or SATB2 enables gene silencing by Xist in embryonic fibroblasts, which normally do not provide an initiation context. Thus, SATB1 functions as a crucial initiation factor and may act to organize genes for silencing by Xist during the initiation of X inactivation.
SATB1 defines the developmental context for gene silencing by Xist in lymphoma and embryonic cells.
Specimen part
View SamplesPatients with the genetic skin blistering disease recessive dystrophic epidermolysis bullosa (RDEB) develop aggressive and metastatic cutaneous squamous cell carcinoma which is the principal cause of premature mortality in this patient group. We performed gene expression profiling of RDEB-SCC cells compared to RDEB keratinocytes in order to identify tumor-specific molecules that could potentially be exploited for detection, diagnosis, and therapy of this devastating disease.
Extracellular Vesicles as Biomarkers for the Detection of a Tumor Marker Gene in Epidermolysis Bullosa-Associated Squamous Cell Carcinoma.
Specimen part, Disease
View SamplesPrimary human cytomegalovirus (HCMV) infection usually goes unnoticed, causing mild or no symptoms in immunocompetent individuals. Some rare severe clinical cases have however been reported without investigation of host immune responses or viral virulence. In this present study, we investigate, for the first time, phenotypic and functional features together with gene expression profiles in immunocompetent adults experiencing a severe primary HCMV infection. Twenty PHIP were enrolled as well as 26 HCMV-seronegative and 39 HCMV-seropositive healthy controls. PHIP had a huge lymphocytosis marked by massive expansion of NK and T cell compartments. Interestingly, PHIP mounted efficient innate and adaptive immune responses with a deep HCMV imprint, revealed mainly by the expansion of NKG2C+ NK cells, CD16+ V2- T cells and conventional HCMV-specific CD8+ T cells. The main effector lymphocytes were activated and displayed an early immune phenotype that developed toward a more mature differentiated status. We suggest that both huge lymphocytosis and excessive lymphocyte activation could contribute to a massive cytokine production known to mediate tissue damage observed in PHIP. Taken together, these findings bring new insights into the comprehensive understanding of immune mechanisms involved during primary HCMV-infection in immunocompetent individuals.
Severe Symptomatic Primary Human Cytomegalovirus Infection despite Effective Innate and Adaptive Immune Responses.
Disease
View SamplesComparison of wild type Populus to transgenics expressing either a miRNA-resistant Populus ortholog of ATHB15/CORONA or miRNA-resistant Populus ortholog of REVOLUTA
The Populus class III HD ZIP, popREVOLUTA, influences cambium initiation and patterning of woody stems.
Specimen part
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Conversion of Human Gastric Epithelial Cells to Multipotent Endodermal Progenitors using Defined Small Molecules.
Specimen part
View SamplesEndodermal stem/progenitor cells have diverse potential applications in research and regenerative medicine, so a readily available source could have widespread uses. Here we describe derivation of human induced endodermal progenitor cells (hiEndoPCs) from gastrointestinal epithelial cells using a cocktail of defined small molecules along with support from tissue-specific mesenchymal feeders. The hiEndoPCs show clonal expansion in culture and give rise to hepatocytes, pancreatic endocrine cells, and intestinal epithelial cells when treated with defined soluble molecules directing differentiation. The hiEndoPC-derived hepatocytes are able to rescue liver failure in Fah-/-Rag2-/- mice after transplantation, and, unlike hESCs, transplanted hiEndoPCs do not give rise to teratomas. Since human gastric epithelial cells are readily available from donors of many ages, this conversion strategy can generate clonally expandable cell populations with a variety of potential applications, including personalized drug screening and therapeutic strategies for liver failure and diabetes.
Conversion of Human Gastric Epithelial Cells to Multipotent Endodermal Progenitors using Defined Small Molecules.
Specimen part
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