Project description:To characterize the molecular changes in myelodysplastic syndromes (MDS) and to explore novel genetic abnormalities occurring in these disorders through a genome-wide study in a series of MDS and MDS/MPN patients. A total of 285 abnormalities were identified in 71 patients. Three high-risk MDS cases displayed chromothripsis. In addition, cryptic deletions were identified in genomic regions where MDS-related genes, such as DNMT3A (2p23.3), TET2 (4q24), RUNX1 (21q22) and BCOR (Xp11.4), are located.
Project description:Recent studies have shown that epigenetic regulator are mutated in myelodysplastic syndrome (MDS) patients. Ezh2 is frequently mutated in hematopoietic malignant patients, however, the pathophysiological role of Ezh2 mutations has not been elucidated yet. In this study, we examined the function of Ezh2 in murine hematopoietic disease. Ezh2 deleted mice with myeloid malignancies including MDS, Myelodysplasia/myeloneoplasm(MDS/MPN), Myelodysplasia/myeloneoplasm_thrombocytosis(MDS/MPN_TC)
Project description:In this study, we assessed the effects of lysyl oxidase (LOX/LOXL) inhibition on the composition of extracellular matrix (ECM) produced by in vitro expanded bone marrow derived mesenchymal stromal cells (MSCs) of n=3 patients with myelodysplastic syndromes (MDS) and myeloproliferative neoplasms (MPN).
Project description:Kynureninase is a member of a large family of catalytically diverse but structurally homologous pyridoxal 5'-phosphate (PLP) dependent enzymes known as the aspartate aminotransferase superfamily or alpha-family. The Homo sapiens and other eukaryotic constitutive kynureninases preferentially catalyze the hydrolytic cleavage of 3-hydroxy-l-kynurenine to produce 3-hydroxyanthranilate and l-alanine, while l-kynurenine is the substrate of many prokaryotic inducible kynureninases. The human enzyme was cloned with an N-terminal hexahistidine tag, expressed, and purified from a bacterial expression system using Ni metal ion affinity chromatography. Kinetic characterization of the recombinant enzyme reveals classic Michaelis-Menten behavior, with a Km of 28.3 +/- 1.9 microM and a specific activity of 1.75 micromol min-1 mg-1 for 3-hydroxy-dl-kynurenine. Crystals of recombinant kynureninase that diffracted to 2.0 A were obtained, and the atomic structure of the PLP-bound holoenzyme was determined by molecular replacement using the Pseudomonas fluorescens kynureninase structure (PDB entry 1qz9) as the phasing model. A structural superposition with the P. fluorescens kynureninase revealed that these two structures resemble the "open" and "closed" conformations of aspartate aminotransferase. The comparison illustrates the dynamic nature of these proteins' small domains and reveals a role for Arg-434 similar to its role in other AAT alpha-family members. Docking of 3-hydroxy-l-kynurenine into the human kynureninase active site suggests that Asn-333 and His-102 are involved in substrate binding and molecular discrimination between inducible and constitutive kynureninase substrates.
Project description:Genomic studies in chronic myeloid malignancies, including myeloproliferative neoplasms (MPN), myelodysplastic syndromes (MDS) and MPN/MDS, have identified common mutations in genes encoding signaling, epigenetic, transcription and splicing factors. Analysis of 18 of these genes in a cohort of 224 chronic myelomonocytic leukemias (CMML), which is the most frequent MPN/MDS, identified at least one mutated gene in 95% of the patients, with some of the mutations affecting the disease phenotype. The number of mutated genes negatively affected progression-free and overall survival in multivariate analysis. Analysis of sorted progenitors indicated an early amplification of the CMML clone at the CD34+/CD38- stage of hematopoiesis, together with a premature granulomonocytic differentiation skewing. We interrogated the clone architecture by mutation-specific discrimination analysis of single-cell-derived colonies. The genetic classification of individual colonies allowed a designation of sub-clones and the assembly of putative evolutionary trees, indicating a linear acquisition of the studied mutations. Analysis of matched pre- and post-treatment samples demonstrated clonal persistence with limited and selective elimination of sub-clones. The disease was characterized by an amplification of multipotent and common myeloid progenitors in the CD34+ compartment, both fractions showing increased granulomonocytic differentiation at the expense of erythroid progenitors, contrasting with normal granulomonocytic progenitors. Altogether, early amplification of the leukemic clone and increased granulomonocytic differentiation of early progenitors may account for the specificity of CMML among myeloid neoplasms. This experiment correspond to the analysis of gene expression profiles in total CD34+ cells from the peripheral blood of 15 patients (Chronic Myelomonocytic Leukemia) and 4 healthy controls.
Project description:We have sequenced miRNA libraries from human embryonic, neural and foetal mesenchymal stem cells. We report that the majority of miRNA genes encode mature isomers that vary in size by one or more bases at the 3’ and/or 5’ end of the miRNA. Northern blotting for individual miRNAs showed that the proportions of isomiRs expressed by a single miRNA gene often differ between cell and tissue types. IsomiRs were readily co-immunoprecipitated with Argonaute proteins in vivo and were active in luciferase assays, indicating that they are functional. Bioinformatics analysis predicts substantial differences in targeting between miRNAs with minor 5’ differences and in support of this we report that a 5’ isomiR-9-1 gained the ability to inhibit the expression of DNMT3B and NCAM2 but lost the ability to inhibit CDH1 in vitro. This result was confirmed by the use of isomiR-specific sponges. Our analysis of the miRGator database indicates that a small percentage of human miRNA genes express isomiRs as the dominant transcript in certain cell types and analysis of miRBase shows that 5’ isomiRs have replaced canonical miRNAs many times during evolution. This strongly indicates that isomiRs are of functional importance and have contributed to the evolution of miRNA genes
Project description:Transcriptional profiling of Homo sapiens inflammatory skin diseases (whole skin biospies): Psoriasis (Pso), vs Atopic Dermatitis (AD) vs Lichen planus (Li), vs Contact Eczema (KE), vs Healthy control (KO) In recent years, different genes and proteins have been highlighted as potential biomarkers for psoriasis, one of the most common inflammatory skin diseases worldwide. However, most of these markers are not psoriasis-specific but also found in other inflammatory disorders. We performed an unsupervised cluster analysis of gene expression profiles in 150 psoriasis patients and other inflammatory skin diseases (atopic dermatitis, lichen planus, contact eczema, and healthy controls). We identified a cluster of IL-17/TNFα-associated genes specifically expressed in psoriasis, among which IL-36γ was the most outstanding marker. In subsequent immunohistological analyses IL-36γ was confirmed to be expressed in psoriasis lesions only. IL-36γ peripheral blood serum levels were found to be closely associated with disease activity, and they decreased after anti-TNFα-treatment. Furthermore, IL-36γ immunohistochemistry was found to be a helpful marker in the histological differential diagnosis between psoriasis and eczema in diagnostically challenging cases. These features highlight IL-36γ as a valuable biomarker in psoriasis patients, both for diagnostic purposes and measurement of disease activity during the clinical course. Furthermore, IL-36γ might also provide a future drug target, due to its potential amplifier role in TNFα- and IL-17 pathways in psoriatic skin inflammation. In recent years, different genes and proteins have been highlighted as potential biomarkers for psoriasis, one of the most common inflammatory skin diseases worldwide. However, most of these markers are not psoriasis-specific but also found in other inflammatory disorders. We performed an unsupervised cluster analysis of gene expression profiles in 150 psoriasis patients and other inflammatory skin diseases (atopic dermatitis, lichen planus, contact eczema, and healthy controls). We identified a cluster of IL-17/TNFα-associated genes specifically expressed in psoriasis, among which IL-36γ was the most outstanding marker. In subsequent immunohistological analyses IL-36γ was confirmed to be expressed in psoriasis lesions only. IL-36γ peripheral blood serum levels were found to be closely associated with disease activity, and they decreased after anti-TNFα-treatment. Furthermore, IL-36γ immunohistochemistry was found to be a helpful marker in the histological differential diagnosis between psoriasis and eczema in diagnostically challenging cases. These features highlight IL-36γ as a valuable biomarker in psoriasis patients, both for diagnostic purposes and measurement of disease activity during the clinical course. Furthermore, IL-36γ might also provide a future drug target, due to its potential amplifier role in TNFα- and IL-17 pathways in psoriatic skin inflammation.