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:<p>Non-coding regions comprise most of the human genome and harbor a significant fraction of risk alleles for neuropsychiatric diseases, yet their functions remain poorly defined. We created a high-resolution map of non-coding elements involved in human cortical neurogenesis by contrasting chromatin accessibility and gene expression in the germinal zone and cortical plate of the developing cerebral cortex. To obtain a high resolution depiction of chromatin structure and gene expression in developing human fetal cortex, we dissected the post-conception week (PCW) 15-17 human neocortex into two major anatomical divisions to distinguish between proliferating neural progenitors and post mitotic neurons: (1) GZ: the neural progenitor-enriched region encompassing the ventricular zone (VZ), subventricular zone (SVZ), and intermediate zone (IZ) and (2) CP: the neuron-enriched region containing the subplate (SP), cortical plate (CP), and marginal zone (MZ). Tissues were obtained from three independent donors and three to four technical replicates from each tissue were processed for ATAC-seq to define the landscape of accessible chromatin and RNA-seq for genome-wide gene expression profiling.</p>
Project description:Gene regulation in mammals involves a complex interplay between promoter and distal regulatory elements that function in concert to drive precise spatio-temporal gene expression programs. However, the dynamics of distal gene regulatory elements and its function in transcriptional reprogramming that underlies neurogenesis and neuronal activity remain largely unknown. Here we use a combinatorial analysis of genomewide datasets for chromatin accessibility (FAIRE-Seq) and enhancer mark H3K27ac to reveal a highly dynamic nature of chromatin accessibility during neurogenesis that gets restricted to certain genomic regions as neurons acquire a post-mitotic, terminally differentiated state. We further reveal that the distal open regions serve as target sites of distinct transcription factors that function in a stage-specific manner to contribute to the transcriptional program underlying neuronal commitment and maturation. A prolonged NMDA-driven neural activity results in epigenetic reprogramming at a large number of distal regulatory elements as well as dramatic reorganization of super-enhancers that in turn mediate critical transcriptional responses. Taken together, these findings reveal dynamics of distal regulatory landscape during neurogenesis and uncover novel regulatory elements that function in concert with epigenetic mechanisms and transcription factors to generate transcriptome underlying neuronal development and function. FAIRE-Seq and H3K27ac profiles for three stages on neuronal differentation viz. neuronal progenitors, day 1 neurons and day 10 neurons, were generated to understand the dynamics of accessible and ehancer chromatin landscape. Along with this we also generated RNASeq and H3K27ac profiles for day 10 neurons upon control and NMDA treatment.
Project description:We aim to profile the dynamic changes of chromatin accessibility (openness) to transcription factors during cortical neuron differentiation from human iPSCs. We used ATAC-seq to map open chromatins in iPSCs, neural stem cells (NSCs) at day 27 and day 33 of neural induction (designated as iN-d30 for simplicity), and neurons at day 41 (iN-d41). We found that there were robust dynamic changes of open chromatins that are corresponding to cell stage-specific gene function both at genome-wide level and at individual loci of interest to neurodevelopment and psychiatric disorders, with NSC (iN-d30) gaining most (89%) of the neuron specific open chromatin peaks. Open chromatin peaks shared by different cell stages were overrepresented in core promoters, while the peaks specific to each cell stage or showing dynamic change of openness were enriched in introns and intergenic sequences. The dynamic change of open chromatins is orchestrated by specific sets of transcription factors (TFs) in each cell stage, providing epigenomic support the central role of NEUROD1 and NEUROG2 in cortical neuron differentiation.
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. Two-condition experiment, Normoxic MSCs vs. Hypoxic MSCs.
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: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 methylation profiling of immortalized human mesenchymal stem cells comparing HPV E6/E7-transfected MSCs cells with human telomerase reverse transcriptase (hTERT)- and HPV E6/E7-transfected MSCs. hTERT may increase gene methylation in MSCs. Goal was to determine the effects of different transfected genes on global gene methylation in MSCs.