SIRT6 regulates redox homeostasis in human mesenchymal stem cells by the transactivation of NRF2
Ontology highlight
ABSTRACT: We investigated the effect of SIRT6-knockout on gene expression and H3K4me3 modification profile in human mesenchymal stem cells. RNAs isolated from SIRT6+/+ and SIRT6-/- hMSCs at early and late passages were sequenced, respectively. And, H3K4me3 ChIP-seq was performed upon the SIRT6 deleted hMSC and WT at early stage, respectively.
Project description:Chromatin remodeling proteins are frequently dysregulated in human cancer, yet little is known about how they control tumorigenesis. Here, we uncover an epigenetic program mediated by the NAD+-dependent histone deacetylase Sirtuin 6 (SIRT6) that is critical for suppression of pancreatic ductal adenocarcinoma (PDAC), one of the most lethal malignancies. SIRT6 inactivation accelerates PDAC progression and metastasis via upregulation of Lin28b, a negative regulator of the let-7 microRNA. SIRT6 loss results in histone hyperacetylation at the Lin28b promoter, Myc recruitment, and pronounced induction of Lin28b and downstream let-7 target genes, HMGA2, IGF2BP1 and IGF2BP3. This epigenetic program defines a distinct subset representing 30-40% of human PDAC, characterized by poor prognosis and an exquisite dependence on Lin28b for tumor growth. Thus, we identify SIRT6 as an important PDAC tumor suppressor, and uncover the Lin28b pathway as a potential therapeutic target in a molecularlydefined PDAC subset. ChIP-Seq experiments to examine H3K56ac histone modifications in murine PDAC cells that are Sirt6 wild type (WT), Sirt6 knock-out (KO), and Sirt6 KO cells engineered to express Sirt6 WT (Sirt6 KO + Sirt6 WT Restored).
Project description:Unraveling complex signaling programs animating developmental lineage-decisions is pivotal to differentiate human pluripotent stem cells (hPSC) into pure populations of desired lineages for regenerative medicine. Developmental signals are strikingly temporally dynamic: BMP and Wnt initially specify primitive streak (progenitor to endoderm) yet 24 hours later suppress endoderm and induce mesoderm. At lineage bifurcations we show mutually-exclusive embryonic lineages are segregated through cross-repressive signals: TGFM-NM-2 and BMP/MAPK duel to respectively specify pancreas versus liver from endoderm. Unilateral endodermal differentiation requires blockade of alternative fates at every stage, revealing a universal developmental strategy for efficient differentiation and anterior-posterior patterning of diverse hPSC lines into highly-pure endodermal populations. This culminated in hPSC-derived hepatic progenitors that, for the first time, engraft long-term in genetically-unconditioned mouse livers and secrete human albumin. Finally, thirty transcriptional and chromatin state maps capturing endoderm commitment revealed endodermal enhancers reside in an unanticipated diversity of "pre-enhancer" chromatin states before activation. Endoderm RNA-seq and ChIP-seq data sets
Project description:We report the differential roles of an HDAC inhibitor-TSA during hESC nerual commitment. In the initiation of hESC differentiation, TSA could inhibit the downregulation of pluripotency genes to maintain pluripotency, whereas in the neural commitment stage, TSA could promote neural gene expression to assist hESC nerual determination. Examination of gene expression patterns in hESCs, day 4 or day 8 differentiated cells without or with TSA treatment
Project description:The extremely low efficiency of human embryonic stem cell (hESC) derivation using somatic cell nuclear transfer (SCNT) limits potential application. Blastocyst formation from human SCNT embryos occurs at a low rate and with only some oocyte donors. We previously showed in mice that reduction of histone H3 lysine 9 trimethylation (H3K9me3) through ectopic expression of the H3K9me3 demethylase Kdm4d greatly improves SCNT embryo development. Here we show that overexpression of a related H3K9me3 demethylase KDM4A improves human SCNT, and that, as in mice, H3K9me3 in the human somatic cell genome is an SCNT reprogramming barrier. Overexpression of KDM4A significantly improves the blastocyst formation rate in human SCNT embryos by facilitating transcriptional reprogramming, allowing derivation of NTESCs from all oocyte donors tested using adult AMD patient somatic nuclei donors. This conserved mechanistic insight has potential applications for improving SCNT in a variety of contexts, including regenerative medicine. Here we perform RNA-seq based transcriptome profiling in human Donor (fibroblast cells), in vitro fertilized embryos at 8-cell stages (IVF_8Cell), somatic cell nuclear transfer embryos at 8-cell stages (SCNT_8Cell), SCNT assisted by KDM4A 8-cell embryos (SCNT_KDM4A_8Cell). Besides, we also perform RNA-seq in Control human ES cells (CTR_hES) and SCNT assisted by KDM4A derived human ES cells (NTK) with duplicates.Â
Project description:Huntington’s disease (HD) is a devastating neurological disorder that is caused by an expansion of the poly-Q tract in exon 1 of the Huntingtin gene (HTT). HTT is an evolutionarily conserved and ubiquitously expressed protein that has been linked to a variety of functions including transcriptional regulation, mitochondrial function, and vesicle transport. This large protein has numerous caspase and calpain cleavage sites and can be decorated with several post-translational modifications such as phosphorylations, acetylations, sumoylations, and palmitoylations. However, the exact function of HTT and the role played by its modifications in the cell is still not well understood. Scrutiny of HTT function has been focused on a single, full length, mRNA. In this study, we report the discovery of 5 novel HTT mRNA splice isoforms that are expressed in normal and HD-hESC lines as well as cortical neurons differentiated from hESCs. Interestingly, none of the novel isoforms generates a truncated protein. Instead, 4 of the 5 new isoforms specifically eliminate domains and modifications to generate smaller HTT proteins. The fifth novel isoform incorporates a previously unreported additional exon, dubbed 41b, which is hominid-specific and introduces a potential phosphorylation site in the protein. The discovery of this hominid-specific isoform may shed light on human-specific pathogenic mechanisms of HTT, which could not be investigated with current mouse models of the disease. Furthermore, it provides a new human-specific target for drug screening in Huntington’s disease. We performed RNAseq of human embryonic stem cells in pluripotency conditions to check expression of multiple HTT isoforms.
Project description:During cerebellar development, the main portion of the cerebellar plate neuroepithelium (NE) gives birth to Purkinje cells and interneurons, while the germinal zone at its dorsal edge, called the rhombic lip (RL), generates granule cells and cerebellar nuclei neurons. However, it remains elusive how these components work together to generate the intricate structure of the cerebellar anlage. In this study, we found that a polarized cerebellar anlage structure self-organizes in three-dimensional (3D) human ES cell (hESC) culture. This NE is capable of differentiating into electrophysiologically functional Purkinje cells. The addition of FGF19 promotes spontaneous generation of dorsoventrally polarized NE structures containing cerebellar and basal plates. Furthermore, further addition of SDF1 promoted the generation of stratified cerebellar plate NE with RL-like germinal zones self-forming at the edge. Thus, hESC-derived cerebellar progenitors exhibit substantial self-organizing potential for generating a polarized structure reminiscent of the early human cerebellar anlage at the first trimester. Examination of mRNA profile in two different treated human ES cells .
Project description:SIRT6 has been implicated in a range of biological processes including inflammation, aging and the control of metabolism. Hence inhibitors or activators of SIRT6 have the potential to be therapeutics for a number of indications. Genome wide expression studies were used to investigate the effect of overexpression of SIRT6 and mutant SIRT6 on a wide range of NFκB dependent gene expression HEK293 cells were transfected with expression vectors encoding wild type SIRT6 or the H133W mutant followed by stimulation with TNFα for one hour.
Project description:Generation of research quality, clinically relevant cell types in vitro from human pluripotent stem cells (hPSCs) requires detailed understanding of the equivalent cell types in humans. Here we analyzed 130 human fetal samples at 6-20 weeks of development and identified the stages in which human cKIT+ primordial germ cells (PGCs), the precursors of gametes, undergo whole genome epigenetic reprogramming and ultimately initiation of imprint erasure with loss of both 5mC and 5-hydroxy-mC at differentially methylated regions. Using five alternate in vitro differentiation strategies combined with a single-cell microfluidic analysis, high throughput RNA sequencing and a bona fide human cKIT+ PGC signature, we show that hPSC differentiation generates a rare cKIT+ PGC subtype found in both the human fetal gonad and mouse embryo. Taken together, our study creates a resource of human germ line ontogeny that is absolutely essential for future studies aimed at interpreting in vitro differentiation of the human germ line. cKIT+ cells analyzed from 2 biological samples for testes and 2 samples for ovaries at 16 and 16.5 weeks. 3 biological replicates of TRA-1-60+ cells sorted from H1 hESCs
Project description:Total RNA extracted from differentiated mesenchymal stem cells at four time points (T1,T2,T3,T4) and sequenced using Illumina Hi-seq 2000 platform to generate RNA sequencing with 101bp in read length. Nearly 50 million raw reads were yielded from each sample respectively. We used FastQC to confirm the quality of raw fastq sequencing data, and SOAPfuse software to detect fusion transcripts. Discovering fusion genes from muscle differentiated mesenchymal stem cells
Project description:To find the SIRT6 and SIRT7 binding proteins, we expressed V5-tagged SIRT6 and SIRT7 and pulled down this protein with anti-V5 agarose affinity gel. Sirtuins are a family of NAD-dependent deacetylases which deacetylate not only histones but also a wide range of target proteins. Sirtuins are conserved from yeast to mammal, and are known to regulate many processes such as cellular metabolism, apoptosis, cellular senescence, cell cycle, and organism-level aging. Among the members of sirtuins showing different subcellular localization, SIRT1, SIRT6 and SIRT7 are localized in nucleus. Whereas many functions and interacting proteins of SIRT1 have been studied, functions of SIRT6 and SIRT7 are not extensively revealed yet. Since it is important to understand the molecular function of SIRT6 and SIRT7, we here aimed to identify interacting proteins in mammalian cells.<br>Extra primary submitter: <a href="mailto:nglee@postech.ac.kr" target="_top">Namgyu Lee</a>, Department of Life Sciences, Pohang University of Science and Technology, Pohang, 790-784, Republic of Korea<br>Lab head: <a href="mailto:kchoi@postech.ac.kr" target="_top">Kwan Yong Choi</a>, Department of Life Sciences and Division of Integrative Biosciences and Biotechnology, Pohang University of Science and Technology, Pohang, 790-784, Republ ic of Korea