| 1. |
- Gidlöf, Olof, et al.
(författare)
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Inhibition of the long non-coding RNA NEAT1 protects cardiomyocytes from hypoxia in vitro via decreased pri-miRNA processing
- 2020
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Ingår i: Cell Death and Disease. - : Springer Science and Business Media LLC. - 2041-4889. ; 11:8
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Tidskriftsartikel (refereegranskat)abstract
- While restoration of coronary blood flow to the ischemic heart is the most effective strategy for reducing infarct size, reperfusion injury represents a significant limiting factor on clinical outcomes in myocardial infarction patients. Ischemic preconditioning (IPC) has been shown to inhibit reperfusion injury and represents an attractive model for studying cardioprotective signal transduction pathways. Long non-coding RNAs (lncRNAs) are a structurally and functionally heterogenous class of RNA transcripts with unknown roles in IPC-induced cardioprotection. Through microarray-based expression profiling of 31,423 lncRNAs in cardiac tissue from IPC mice, we identified the nuclear transcript Neat1 to be rapidly and robustly decreased in response to IPC. siRNA-mediated knock down of Neat1 reduced apoptosis and necrosis in murine cardiomyocytes (CM) and human iPS-derived CMs in response to prolonged hypoxia and hypoxia-reoxygenation, assessed with Annexin V/propidium iodide-staining, a Caspase 3/7 activity assay, LDH release, and western blot for cleaved Caspase 3. Mechanistically, Neat1 was shown to regulate processing of pro-apoptotic microRNA-22 (miR-22) in murine and human CM nuclei using a luciferase reporter assay. Hypoxia-induced downregulation of Neat1 was shown to result in accumulation of unprocessed pri-miRNA and decreased availability of biologically active miRNA, including miR-22. Addition of exogenous synthetic miR-22 reversed the protective effect of Neat1 knock down in human iPS-CM. In conclusion, we have identified the nuclear lncRNA Neat1 as part of a conserved oxygen-sensitive feedback mechanism by regulation of miRNA processing and a potential target in cardioprotection.
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| 2. |
- Gidlöf, Olof, et al.
(författare)
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Ischemic Preconditioning Confers Epigenetic Repression of Mtor and Induction of Autophagy Through G9a-Dependent H3K9 Dimethylation
- 2016
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Ingår i: Journal of the American Heart Association. - 2047-9980. ; 5:12
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Ischemic preconditioning (IPC) protects the heart from prolonged ischemic insult and reperfusion injury through a poorly understood mechanism. Post-translational modifications of histone residues can confer rapid and drastic switches in gene expression in response to various stimuli, including ischemia. The aim of this study was to investigate the effect of histone methylation in the response to cardiac ischemic preconditioning.METHODS AND RESULTS: We used cardiac biopsies from mice subjected to IPC to quantify global levels of 3 of the most well-studied histone methylation marks (H3K9me2, H3K27me3, and H3K4me3) with Western blot and found that H3K9me2 levels were significantly increased in the area at risk compared to remote myocardium. In order to assess which genes were affected by the increase in H3K9me2 levels, we performed ChIP-Seq and transcriptome profiling using microarray. Two hundred thirty-seven genes were both transcriptionally repressed and enriched in H3K9me2 in the area at risk of IPC mice. Of these, Mtor (Mechanistic target of rapamycin) was chosen for mechanistic studies. Knockdown of the major H3K9 methyltransferase G9a resulted in a significant decrease in H3K9me2 levels across Mtor, increased Mtor expression, as well as decreased autophagic activity in response to rapamycin and serum starvation.CONCLUSIONS: IPC confers an increase of H3K9me2 levels throughout the Mtor gene-a master regulator of cellular metabolism and a key player in the cardioprotective effect of IPC-leading to transcriptional repression via the methyltransferase G9a. The results of this study indicate that G9a has an important role in regulating cardiac autophagy and the cardioprotective effect of IPC.
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| 3. |
- Haniffa, Muzlifah, et al.
(författare)
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A roadmap for the Human Developmental Cell Atlas
- 2021
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Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 597:7875, s. 196-205
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Tidskriftsartikel (refereegranskat)abstract
- This Perspective outlines the Human Developmental Cell Atlas initiative, which uses state-of-the-art technologies to map and model human development across gestation, and discusses the early milestones that have been achieved. The Human Developmental Cell Atlas (HDCA) initiative, which is part of the Human Cell Atlas, aims to create a comprehensive reference map of cells during development. This will be critical to understanding normal organogenesis, the effect of mutations, environmental factors and infectious agents on human development, congenital and childhood disorders, and the cellular basis of ageing, cancer and regenerative medicine. Here we outline the HDCA initiative and the challenges of mapping and modelling human development using state-of-the-art technologies to create a reference atlas across gestation. Similar to the Human Genome Project, the HDCA will integrate the output from a growing community of scientists who are mapping human development into a unified atlas. We describe the early milestones that have been achieved and the use of human stem-cell-derived cultures, organoids and animal models to inform the HDCA, especially for prenatal tissues that are hard to acquire. Finally, we provide a roadmap towards a complete atlas of human development.
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| 4. |
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| 5. |
- Kahn, Robin, et al.
(författare)
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Neutrophil-derived proteinase 3 induces kallikrein-independent release of a novel vasoactive kinin.
- 2009
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Ingår i: Journal of immunology. - : The American Association of Immunologists. - 1550-6606 .- 0022-1767. ; 182:12, s. 7906-7915
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Tidskriftsartikel (refereegranskat)abstract
- The kinin-forming pathway is activated on endothelial cells and neutrophils when high-molecular weight kininogen (HK) is cleaved by plasma kallikrein liberating bradykinin, a potent mediator of inflammation. Kinins are released during inflammatory conditions such as vasculitis, associated with neutrophil influx around blood vessels. Some patients with vasculitis have elevated plasma levels of neutrophil-derived proteinase 3 (PR3) and anti-PR3 Abs. This study investigated if neutrophil-derived PR3 could induce activation of the kinin pathway. PR3 incubated with HK, or a synthetic peptide derived from HK, induced breakdown and release of a novel tridecapeptide termed PR3-kinin, NH(2)-MKRPPGFSPFRSS-COOH, consisting of bradykinin with two additional amino acids on each terminus. The reaction was specific and inhibited by anti-PR3 and alpha(1)-antitrypsin. Recombinant wild-type PR3 incubated with HK induced HK breakdown, whereas mutated PR3, lacking enzymatic activity, did not. PR3-kinin bound to and activated human kinin B(1) receptors, but did not bind to B(2) receptors, expressed by transfected HEK293 cells in vitro. In human plasma PR3-kinin was further processed to the B(2) receptor agonist bradykinin. PR3-kinin exerted a hypotensive effect in vivo through both B(1) and B(2) receptors as demonstrated using wild-type and B(1) overexpressing rats as well as wild-type and B(2) receptor knockout mice. Neutrophil extracts from vasculitis patients and healthy controls contained comparable amounts of PR3 and induced HK proteolysis, an effect that was abolished when PR3 was immunoadsorbed. Neutrophil-derived PR3 can proteolyze HK and liberate PR3-kinin, thereby initiating kallikrein-independent activation of the kinin pathway.
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| 6. |
- Lechman, Eric R, et al.
(författare)
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miR-126 Regulates Distinct Self-Renewal Outcomes in Normal and Malignant Hematopoietic Stem Cells.
- 2016
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Ingår i: Cancer Cell. - : Elsevier BV. - 1878-3686 .- 1535-6108. ; 29:2, s. 214-228
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Tidskriftsartikel (refereegranskat)abstract
- To investigate miRNA function in human acute myeloid leukemia (AML) stem cells (LSC), we generated a prognostic LSC-associated miRNA signature derived from functionally validated subpopulations of AML samples. For one signature miRNA, miR-126, high bioactivity aggregated all in vivo patient sample LSC activity into a single sorted population, tightly coupling miR-126 expression to LSC function. Through functional studies, miR-126 was found to restrain cell cycle progression, prevent differentiation, and increase self-renewal of primary LSC in vivo. Compared with prior results showing miR-126 regulation of normal hematopoietic stem cell (HSC) cycling, these functional stem effects are opposite between LSC and HSC. Combined transcriptome and proteome analysis demonstrates that miR-126 targets the PI3K/AKT/MTOR signaling pathway, preserving LSC quiescence and promoting chemotherapy resistance.
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| 7. |
- Pinto, Dalila, et al.
(författare)
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Functional impact of global rare copy number variation in autism spectrum disorders.
- 2010
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Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 466:7304, s. 368-372
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Tidskriftsartikel (refereegranskat)abstract
- The autism spectrum disorders (ASDs) are a group of conditions characterized by impairments in reciprocal social interaction and communication, and the presence of restricted and repetitive behaviours. Individuals with an ASD vary greatly in cognitive development, which can range from above average to intellectual disability. Although ASDs are known to be highly heritable ( approximately 90%), the underlying genetic determinants are still largely unknown. Here we analysed the genome-wide characteristics of rare (<1% frequency) copy number variation in ASD using dense genotyping arrays. When comparing 996 ASD individuals of European ancestry to 1,287 matched controls, cases were found to carry a higher global burden of rare, genic copy number variants (CNVs) (1.19 fold, P = 0.012), especially so for loci previously implicated in either ASD and/or intellectual disability (1.69 fold, P = 3.4 x 10(-4)). Among the CNVs there were numerous de novo and inherited events, sometimes in combination in a given family, implicating many novel ASD genes such as SHANK2, SYNGAP1, DLGAP2 and the X-linked DDX53-PTCHD1 locus. We also discovered an enrichment of CNVs disrupting functional gene sets involved in cellular proliferation, projection and motility, and GTPase/Ras signalling. Our results reveal many new genetic and functional targets in ASD that may lead to final connected pathways.
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