Project description:Gene expression profiling of immortalized human mesenchymal stem cells with hTERT/E6/E7 transfected MSCs. hTERT may change gene expression in MSCs. Goal was to determine the gene expressions of immortalized MSCs.
Project description:Although information on the molecular pathogenesis of Waldenström’s Macroglobulinemia (WM) has greatly improved in recent years, the exact cellular origin and the mechanisms behind WM transformation from IgM MGUS remain undetermined. Here, we undertook an integrative phenotypic, molecular and genomic approach to study clonal B-cells from newly-diagnosed patients with IgM MGUS (n=22), smoldering (n=17), and symptomatic WM (n=10). Through principal-component-analysis of multidimensional flow cytometry data, we demonstrated overlapping phenotypic profiles between clonal B-cells from IgM MGUS, smoldering and symptomatic WM patients. Similarly, virtually no genes were significantly deregulated between FACS-sorted clonal B-cells from the three disease stages. Interestingly, while the transcriptome of the Waldenström’s clone was highly deregulated as compared to CD25-CD22+ normal B-cells, significantly less genes were differentially expressed and specific WM pathways down-regulated while comparing the transcriptome of the Waldenström’s clone vs. its normal phenotypic counterpart: CD25+CD22+dim B-cells. The frequency of specific copy number abnormalities [+4, del(6q23.3-6q25.3), +12, and +18q11-18q23] progressively increased from IgM MGUS and smoldering WM vs. symptomatic WM (18% vs. 20% and 73%, respectively; P =.008), suggesting a multistep transformation of clonal B-cells that albeit benign (i.e.: IgM MGUS and smoldering WM), already harbor the phenotypic and molecular signatures of the malignant Waldenström’s clone. Normal bone marrow CD25+ B-cells, Clonal B-Cells from IgM Monoclonal Gammopathy of Undetermined Significance, and Clonal B-Cells from Waldenström's Macroglobulinemia
Project description:Transcriptional profiling of human mesenchymal stem cells comparing normoxic MSCs cells with hypoxic MSCs cells. Hypoxia may inhibit senescence of MSCs during expansion. Goal was to determine the effects of hypoxia on global MSCs gene expression.
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:Gene expression profiling of immortalized human mesenchymal stem cells with hTERT/E6/E7 transfected MSCs. hTERT may change gene expression in MSCs. Goal was to determine the gene expressions of immortalized MSCs. One-condition experment, gene expression of 3A6