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: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:To assess if human induced pluripotent stem cell-derived mesenchymal stem cells (hiPSC-MSCs) could be induce to acquire dermal papilla (DP) properties (especially hair inductive capacity), hiPSCs were initially programmed in serum-free MSC medium with FGF, TGFbeta and PDGF. Subsequently, hiMSCs were exposed to retinoic acid and activators of WNT, BMP and FGF signaling pathways. Global gene expression profiles were compared among primarily cultured human DP cells, hiPSC-MSCs before and after induction. Human dermal papillae were microdissected and cultured from different donors. Induction from hiPSCs to MSCs and subsequent sorting of CD271+CD90+ subpopulation and thier induction to DP was performed using WD39 hiPSC lines in two independent experimentations to generate hiPSC-MSC-1,hiPSC-MSC-2 ipDPSC-1 and ipDPSC-2. Funding: The Human Stem Cells Informatization Project of the Ministry of Health, Labour and Welfare, Japan
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:It remains controversial whether human induced pluripotent stem cells (hiPSCs) are distinct from human embryonic stem cells (hESCs) in their molecular signatures and differentiation properties. We examined the gene expression and DNA methylation of 49 hiPSC and 10 hESC lines and identified no molecular signatures that distinguished hiPSCs from hESCs. Comparisons of the in vitro directed neural differentiation of 40 hiPSC and four hESC lines showed that most hiPSC clones were comparable to hESCs. However, in seven hiPSC clones, significant amount of undifferentiated cells persisted even after neural differentiation and resulted in teratoma formation when transplantated into mouse brains. These differentiation-defective hiPSC clones were marked by higher expression of several genes, including those expressed from long terminal repeats of human endogenous retroviruses. These data demonstrated that many hiPSC clones are indistinguishable from hESCs, while some defective hiPSC clones need to be eliminated prior to their application for regenerative medicine. We extracted total RNA from 10 hESCs and 40 hiPSCs, and hybridized them to Agilent gene expression microarrays.